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1. HV POWER INPUT gt SWITCH MODE PFC CONTROL gt POWER SUPPLY dc BUS BRAKE 3 PHASE IGBT E POWER MODULE NJ TO FROM GATE b TO CONTROL L DRIVERS BOARD c RM PHASE CURRENT PHASE VOLTAGE BUS CURRENT BUS VOLTAGE MONITOR BOARD ID BLOCK ZERO CROSS BACK EMF SENSE Figure 4 5 3 Phase AC High Voltage Power Stage 4 4 1 1 Electrical Characteristics of the 3 Phase AC BLDC High Voltage Power Stage The electrical characteristics in Table 4 2 apply to operation at 25 C with a 160 Vdc power supply voltage DRMO028 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 67 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design Table 4 2 Electrical Characteristics of Power Stage Characteristic Symbol Min Typ Max Units dc input voltage Vdc 140 160 230 V ac input voltage Vac 100 208 240 V Quiescent current loc 70 mA Min logic 1 input voltage Vin 2 0 V Max logic 0 input voltage Vit E 0 8 V Input resistance Rin 10kQ Analog output range Vout 0 3 3 V Bus current sense voltage Isense 563 mV A Bus voltage sense voltage VBus 8 09 mV V Peak output current lpk 2 8 A ea dissipation Pai __ 50 nt dissipation 100 Total power dissipation Pdiss 85
2. Y Lj 7 er L8 is 3 PC Master S W START STOP SPEED RS232 switch potentiometer 4 gt ji treated PER EE Tg c i BEP T Nr Hou Samet 9 3 JP 13 4 a z 0135 10 OW ee n UR Quv 31 LL to power stage board Figure 6 4 Controller Board 6 4 1 5 EVM Board Settings EVM board settings are the same for all hardware platforms CAUTION Remember the MMDS MCU clock must be set to 4 MHz Change the crystal oscillator or set oscillator W1 to MMDS and set for 4 MHz in the debugger 6 4 2 Software Setup In order to run the sensorless BLDC application the following software is needed e Metrowerks compiler for HCO8 installed on your PC computer e Sensorless BLDC application HCO8 software files located in bldc_zerocrosO8MR3z2 directory DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 117 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc For application PC master software remote control the following software is needed e PC master software for PC installed on your PC computer e Sensorless BLDC application PC master software control files located in bldc_zerocrosO8MR32 pc_master directory Both the HC08 and PC master software control files for the sensorless BLDC applic
3. 89 Application State Transitions 90 Stand by State RE a MERARAAERA RIS DEEREEKEREAET C RICH 93 PAD NBI EORR IO ER 94 Back EMF 5 97 R nning RERO T TII CT eR T 101 Leod d d EE PEE dag dd x 102 Fault Siate a tas tne caradeseeeaosenadaedeadcee pecan 103 High Voltage Hardware System Configuration 114 Low Voltage Evaluation Motor Hardware System 115 Low Voltage Hardware System Configuration 116 ERO Board auda dA IE 6d ed a ad de d Rd ee 117 Execute Make 121 PC Master Software Control 124 Follow up for Software Customizing to Customer Motor 128 Follow up for Advanced Software Customizing 129 Follow up for Software Customizing Trouble Shouting 129 PC Master Software Parameters Tuning Control Window 130 PC Master Software Parameters Tuning Control Window 131 PC Master Software Current Parameters Tuning Window 141 PC Master Software Start Parameters Tuning Window 149 PC Master Software Speed Parameters Tuning Window 154 DRMO28 Rev 0 10 MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference M
4. 4 4 2 Optoisolation Board Motorola s embedded motion control series optoisolation board links signals from a controller to a high voltage power stage The board isolates the controller and peripherals that may be attached to the controller from dangerous voltages that are present on the power stage The optoisolation board s galvanic isolation barrier also isolates control signals from high noise in the power stage and provides a noise robust systems architecture Signal translation is virtually one for one Gate drive signals are passed from controller to power stage via high speed high dv dt digital optocouplers Analog feedback signals are passed back through HCNR201 high linearity analog optocouplers Delay times are typically Designer Reference Manual DRMO28 Rev 0 68 Hardware Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design High Voltage Hardware Set Components 250 ns for digital signals and 2 us for analog signals Grounds are separated by the optocouplers galvanic isolation barrier Both input and output connections are made via 40 pin ribbon cable connectors The pin assignments for both connectors are the same For example signal PWM_AT appears on pin 1 of the input connector and also on pin 1 of the output connector In addition to the usual motor control signals an MC68HC705JJ7CDW serves as a Serial link which allows cont
5. Supplied as ECCTR908MR32 DRMO028 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 61 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design Described in MC68HC908MR3 2 Control Board User s Manual Motorola document order number MEMCMR32CBUM D see References 3 e M1 1 823810 Motor Supplied in kit with IB23810 Motor as ECMTREVAL Evaluation Motor Board Kit e U2 3 Phase AC BLDC Low Voltage Power Stage Supplied in kit with IB23810 Motor as ECMTREVAL Evaluation Motor Board Kit Described in Motorola Embedded Motion Control Evaluation Motor Board User s Manual Motorola document order number MEMCEVMBUM D see References 6 The individual modules are described in some sections below More detailed descriptions of the boards can be found in comprehensive User s Manuals belonging to each board References 3 6 These manuals are available on on the World Wide Web at http www motorola com The User s Manual incorporates the schematic of the board description of individual function blocks and a bill of materials An individual board can be ordered from Motorola as a standard product 4 2 3 Low Voltage Hardware Set Configuration The system configuration for low voltage hardware set is shown in Figure 4 3 Designer Reference Manual DRMO28 Rev 0 62 Hardware Design MOTOROLA For More Information
6. 40 3 16 BLDC Commutation with Back EMF Zero Crossing Sensing 42 3 17 BLDC Commutation Time with Zero Crossing Sensing 43 3 18 Vectors of Magnetic 47 3 19 Back EMF at Start 48 3 20 Calculation of the Commutation Times During the Starting Back EMF Acquisition 49 4 1 High Voltage Hardware System Configuration 59 4 2 Low Voltage Evaluation Motor Hardware System 61 4 3 Low Voltage Hardware System Configuration 63 4 4 MC68HC908MR32 Control Board 65 Designer Reference Manual MOTOROLA 9 For More Information On This Product Go to www freescale com Designer Reference Manual Freescale Semiconductor Inc List of Figures 4 5 4 6 5 1 5 10 5 11 5 12 5 13 6 1 6 2 6 3 6 4 6 5 6 6 6 7 6 8 6 9 6 10 6 11 6 12 6 13 6 14 3 Phase AC High Voltage Power 67 BOEK DIOUTI Mr 73 Data Flow aai E ORC tia 78 Main Data Flow Part 2 Alignment Starting Running METTE TTA 80 Closed Loop Control System 81 Main Software Flowchart 84 Main Software Flowchart Main Software Loop 86 Software Flowchart Interrupts
7. MOTOROLA User Guide 133 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 6 5 3 Parameters File Selection NOTE As explained before see Software Setup one of the following files is used for most of software parameters configuration bIldc_zerocrosO8MR32 sources const_cust_hv h definitions for software customizing for high voltage 230 115 Vac power board bIidc_zerocrosO8MR32 sources const_cust_evm h definitions for software customizing for EVM motor board 12 V low power bldc_zerocrosO8MR32 sources const_cust_lv h definitions for software customizing for low voltage 12 Vdc power board According to hardware used the designated file see Table 6 1 must be selected by including bldc_zerocrosO8MR32 sources code_fun c program language functions The following parameter settings will be provided in the selected file Therefore it will be referred to as const_cost_x h in the following sections 6 5 3 1 Software Customizing to Power Stage NOTE The hardware boards parameters customizing is provided in the const_cust_x h file Skip this section when standard modular motion control development hardware boards are used without any changes When low voltage power stage ECLOVACBLDC is configured for 42 V some const_cust_x h changes are needed For setting follow the labels MUST_IF_HW_CHANGE_nn in file const_cust_x h from nn 1 Detailed descript
8. Rev 0 4 MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control DRM028 Rev 0 List of Sections Section 1 Introduction 13 Section 2 System Description 15 Section 3 BLDC Motor Control 23 Section 4 Hardware 57 Section 5 Software Design 75 Section 6 User 109 Appendix A lt 161 Appendix B 163 Designer Reference Manual MOTOROLA 5 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc List of Sections Designer Reference Manual DRMO28 Rev 0 6 MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control DRM028 Rev 0 1 2 1 3 2 1 2 2 2 3 3 1 3 2 3 3 3 4 4 1 4 2 4 3 4 4 4 5 4 6 Table of Contents Section 1 Introduction COMETE 13 Application 13 Benefits of the 13 Section 2 System Description e quc C os ad one cl ee gt C
9. define DUTY PWM MAX 0 942 Modified maximal measurable voltage is 55 V so set define VOLT_HW MAX 55 0 Maximum limit of dc bus voltage should be set according to motor or application requirements but VOLT_MAX_FAULT_V gt 42V define VOLT MAX FAULT V 63 0 Board modified to 42 V has maximal measurable current unchanged define CURR HW MAX A 2 93 define CURR HW MIN A 2 93 Maximum limit of dc bus current should remain unchanged or set according to motor or application requirements define CURR MAX FAULT A 45 0 DRMO28 Rev 0 136 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor When the software parameters are set for the hardware you should follow the settings in Software Customizing to Motor Voltage and Current Settings 6 5 4 Software Customizing to Motor Voltage and Current Settings The software parameter settings according to customer motor are described in this section NOTE _ First of all voltage and current settings need to be done For settings which must be done follow the labels MUST_CHANGE_nn and MUST CHANGE EXPER in file const cust x h where 1 For changes which can be done but usually are not necessary follow the labels CAN CHANGE and CAN CHANGE EXPER in file const cust x h Detailed description starts here 6 5 4 1 Maximal and Minimal Voltage Li
10. 12 Vdc or 42 V Hardware Boards Characteristics Maximum dc bus voltage 16 0 V or 55 0 V Maximal output current 50 0A Motor Brake Set Manufactured EM Brno Czech Republic EM Brno SM40N Motor type 3 phase star connected BLDC motor Pole Number 6 Motor Characteristics Speed range 3000 rpm at 12 V Maximum electrical power 150W Phase voltage 3 6 5 V Phase current 17 A SG40N 3 Phase BLDC Motor Brake Type Nominal Voltage 3 x 27 V Brake Characteristics Nominal Current 2 6 A Pole Number 6 Nominal Speed 1500 rpm Speed range 2500 rpm Input voltage 12 Vdc Maximum dc bus voltage 15 8 V Drive Characteristics Over current over voltage and Proteger under voltage fault protection Load Characteristic Type Varying Designer Reference Manual DRM028 Rev 0 22 System Description MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control Section 3 BLDC Motor Control 3 1 Contents 3 2 Brushless DC Motor Control 23 3 3 Used Control 38 3 4 Application 50 3 2 Brushless DC Motor Control Theory 3 2 1 BLDC Motor Targeted by
11. 55 Implementation This section describes the design of the software blocks of the drive The software will be described in terms of Data Flow e Main Software Flowchart e State Diagram For more information on the control technique used see 3 3 Used Control Technique The control algorithm obtains values from the user interface and sensors processes them and generates 3 phase PWM signals for motor control as can be seen on the data flow analysis shown in Figure 5 1 and Figure 5 2 Designer Reference Manual MOTOROLA Software Design For More Information On This Product Go to www freescale com 75 Freescale Semiconductor Inc 5 3 1 Software Variables and Defined Constants Software Design Important system variables are listed in Table 5 1 Table 5 1 Software Variables Name Type Representing Range Description Sys1 Sys1 Def 8flags System variable 1 lt 0 Speed Min U8 U8 Speed Range Max RPM Minimal speed system units Sp Input lt 0 255 gt Speed input variable used for required speed calculation Coef Speed Inp Coeficient Sp Inp to Speed Desired calculation lt 0 Speed Desired U8 Speed Range Max RPM Desired speed Structure Speed PI regulator parameters Minimal commutation period of the speed U16 UNIT_PERIOD_T2_US range g at Speed Range Max RPM P
12. Commutation time period to discharge coil current us MUST CHANGE 7 define PER DIS US 300 0 Range lt 0 minimal commutation period COEF_TOFF gt It is the maximal allowed current decay period determined by motor winding and maximal current Must be PER DIS US lt minimal motor commutation period us COEF TOFF where COEF TOFF is commutation Toff period coefficient from const h file explained in the section 3 3 Used Control Technique NOTE DIS US is too high it can cause commutation errors at high speed Half Commutation advancing Coefficient CAN CHANGE 9 define COEF HLFCMT 0 375 Range lt 0 1 gt COEF_HLFCMT multiplied by commutation period determines the time from back EMF zero crossing to motor commutation So it sets the electrical angle from back EMF zero crossing to motor commutation step The software controls BLDC motor with a 6 step commutation six commutations per one electrical rotation which means 60 between commutations For ideal commutation with no advancing no field weakening the back EMF zero crossing should be just in the middle between commutations which means that the electrical angle ZC Cmt angle between back EMF zero crossing and commutation is 30 COEF HnPCMT ZC tmt angle 60 EQ 6 6 ZC Cmt angle 15 for COEF_HLFCMT 0 25 ZC Cmt angle 22 5 for COEF_HLFCMT 0 375 ZC Cmt angle 30 for COEF_HLFCMT 0 5 Designer Reference Manual D
13. Freescale Semiconductor Inc Software Design Implementation Notes e The value T2 e g T2 T Cmt Per HlfCmt is calculated using a 16 bit addition with no saturation So the time duration up to 65 536 UNIT PERIOD T2 US from actual time TACNTH TACNTL can be timed at any TACNTH TACNTL timer A counter value e The timer unit UNIT PERIOD T2 US of timer A is determined by the MCU bus frequency 8 MHz with 4 MHz oscillator and default software setting and timer prescaler set in TASC So the default software value is 2 us The timer 2 interrupt function is provided by function TIMACh3_Int DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 107 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Designer Reference Manual DRMO28 Rev 0 108 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control 6 1 Contents Section 6 User Guide 6 2 Application Suitability Ce 11275 6 4 Application Hardware and Software Configuration 6 5 Software Parameters Setting and Tuning f r Customer ca duced crea o4 CCP RERO dee ERROR 6 2 Application Suitability Guide This application suitability guide deals with issues
14. Motorola 2000 Motorola Embedded Motion Control Evaluation Motor Board User s Manual document order number MEMCEVMBUM D Motorola 2000 Motorola Embedded Motion Control 3 Phase BLDC Low Voltage Power Stage User s Manual document order number MEMC3PBLDCLVUM D Motorola 2000 User s Manual for PC Master Software Motorola 2000 found on the World Wide Web at http e www motorola com 68HC908MR32 68HC908MR16 Advance Information document order number MC68HC908MR32 D Motorola Low Cost High Efficiency Sensorless Drive for Brushless DC Designer Reference Manual MOTOROLA References 161 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc References Motor using MC68HC 7 05MC4 document order number AN1627 Motorola Designer Reference Manual DRMO28 Rev 0 162 References MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control DRM028 Rev 0 Appendix B Glossary AC Alternative Current ACIM AC Induction Motor A D converter analog to digital converter ADC analog to digital converter see A D converter back EMF back Electro Motive Force in this document it means the voltage inducted into motor winding due to rotor movement BLDC Brushless DC motor CW CodeWarrior compillers produced by Metro
15. according to the following equation SPEED MAX RPM lt SPEED RANGE MAX RPM EQ 6 10 Minimal speed of the drive rpm MUST CHANGE 12 EXPER define SPEED MIN RPM 500 0 Range 0 SPEED RANGE MAX RPM DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 151 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc SPEED_MIN_RPM determines the minimal desired speed It must be changed for any motor accommodation The minimal speed is also determined by the back EMF zero crossing technique Usually SPEED MIN RPM 0 07 to 0 5 SPEED MAX RPM EQ 6 11 Therefore for low speed requirements minimal speed SPEED MIN RPM must be evaluated experimentally NOTE SPEED MIN RPM can be evaluated with PC master software tuning file tuning bldc pmp Minimal PWM Duty cycle limit CAN CHANGE 11 define DUTY MIN 0 250 Range 0 1 DUTY PWM MIN determines minimal PWM duty cycle limit and in this way it restricts minimal voltage on the motor Therefore DUTY PWM MIN must be changed if its default setting creates a higher voltage than is physically necessary to run with a speed close to SPEED MIN RPM CAUTION Ifthe motor is unable to run down to the speed set in SPEED MIN RPM then decrease DUTY PWM MIN constant Speed PI regulator constants MUST CHANGE 13 EXPER define SPEED PIREG P GAINSCALELEFT 0 Range 0 8 MUST CHANGE 14 EXPE
16. const cust x h Number of commutations per motor revolution MUST CHANGE 9 define COMMUT REV 18 0 Range 0 255 Designer Reference Manual DRMO28 Rev 0 150 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor COMMUT_REV period must be changed for any motor accommodation Set the number of commutations according to the number of rotor poles there are six commutations for one electrical angle revolution Therefore 6 motor poles COMMUT_REV 2 EQ 6 9 Maximal speed range rpm MUST CHANGE 10 define SPEED RANGE MAX RPM 3000 0 Range O infinity Determines scaling of speed variables SPEED RANGE MAX RPM must be changed for any motor accommodation as the software calculates the internal speed variables using this constant For proper speed control it is important to set SPEED RANGE MAX RPM higher then maximal actual motor speed even during speed transient Maximal speed of the drive rpm MUST CHANGE 11 define SPEED MAX RPM 2500 0 Range 0 SPEED RANGE MAX RPM SPEED MAX RPM determines the maximal desired speed It must be changed for any motor accommodation The software calculates the internal speed variables using SPEED RANGE MAX RPM constant For proper speed control it is important that SPEED MAX RPM and SPEED RANGE MAX RPM constants relation must be set
17. protection feature that prevents the motor from unexpected starts e Start the motor Start Motor button To start the motor with PC master software control mode two conditions must be fulfilled START STOP switch on the controller board must be set to STAHT and Start Motor button on PC master software control page must be pressed down e Stop the motor Stop Motor button e Set the required speed of the motor via bar graph e Clear failures Clear Failures button PC master software displays the following information e Required speed of the motor e Actual speed of the motor e dc bus current Temperature of the power stage e Fault status no fault over voltage under voltage or over current in dc bus e Motor status running stopped Hardware board identification is not implemented in the software Therefore the PC master software control window displays Power Stage board Optoisolation board Not Recognized If the fault status is different from the no faults when over current over voltage or under voltage fault the red LED blinks and the motor is stopped This state can be exited by application RESET or Clear Failures button on the PC master software control page It is strongly recommended that you inspect the entire application to locate the source of fault before starting it again Designer Reference Manual MOTOROLA User Guide 125 For More Information On This Product Go to www freescale
18. www freescale com Freescale Semiconductor Inc User Guide Application Hardware and Software Configuration 6 4 3 Software Execution 6 4 3 1 Build To build the BLDC sensorless with the back EMF zero crossing application open the bldc_zerocross mcep project file and execute the Make command as shown in Figure 6 5 This will build and link the application and all needed Metrowerks libraries Metrowerks CodeWarrior File Edit Search 07259 Debug DSP56800 Window Help res Bele hielo ace Add Files Create New Group uu heck Syntay 5 Codec Precompile fe Disassemble HA Depender EEC Source Bring Up To Date Ctrl U 12 files Step ti FBreak Figure 6 5 Execute Make Command 6 4 3 2 Execute from Evaluation Board To execute the application from MMDS evaluation board KITMMDSMR32 choose the Project Debug command in the Code Warrior IDE This will start real time debugger load firmware and application software to evaluation board MMDS The application should then be started from the real time debugger IDE by the Run Start command For more help with these commands refer to the CodeWarrior tutorial documentation located in the CodeWarrior installation directory DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 121 For More Information On This Product Go to www freescale com F
19. 375 at Running state Per Toff n 1 Per ZCrosFlt Coef Toff and Per Dis minimum Per ZCros0O Per ZCros n T ZCrosO T ZCros n e f back EMF zero crossing is missed then Corrective Calculation 2 is made T ZCros n CmtT n Toff n Per ZCros n T ZCros n T ZCros n 1 T ZCros n T ZCrosO Per ZCrosFlt n 1 2 T ZCros n 1 2 T ZCrosO HlfCmt n 1 2 Per ZCrosFlt n l Advance angle Coef HlfCmt Per ZCrosFlt n The best commutation was get with Advance angle 60Deg 1 8 7 5Deg which means Coef HlfCmt 0 375 at Running state Per ZCrosO Per ZCros n T ZCrosO T ZCros n Where T Cmt time of the last commutation T2 Time of the Timer 2 event for Timer Setting T ZCros Time of the last zero crossing T ZCrosO Time of the previous zero crossing Per Toff Period of the zero crossing off Per ZCros Period between zero crossings estimates required commutation period Per ZCros0 Pervious period between zero crossings Per ZCrosFlt Estimated period of commutation filtered Designer Reference Manual DRMO28 Rev 0 44 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Used Control Technique Per HlfCmt Period from zero crossing to commutation half commutation The required commutation timing is provided by setting commutation constants Coef HlfCmt COEF TOFF 3 3 1 4 Start
20. CR_F 1 CURRENT MEASUREMENT CMD_F 1 PC_F 1 ISR MES Figure 5 10 Back EMF Acquisition DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 97 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Service of Commutation As already explained the motor phase commutation is performed in the OC interrupt service routine The phase commutated flag PC_F 1 indicates this action to the scheduler which allows the performed commutation to be serviced Detailed explanation of this state is in Processes Commutation and Zero Crossing Preset and Set Service of Received Back EMF Zero Crossing The back EMF zero crossing is detected by PWM middle function block Then the appropriate flag captured received the zero crossing event ICR_F is set by PWM centre interrupt service routine This indicates to the scheduler that the zero crossing event must be served The following actions are taken 1 Commutation parameters are recalculated more precisely based on the received feedback 2 Commutation time is preset to the output compare register of timer 2 For a better understanding of how the commutation process works see 3 3 1 Sensorless Commutation Control see 3 3 1 5 Starting Commutation Time Calculation BEMF Zero Crossing Sensing Interrupt Service Routine This ISR is used to evaluate the back EMF zero crossing Back EMF is evaluated her
21. CURR Hw MAX A 100 02 ManualMode CURR PIREG P GAIN 1128 777 DEC 1000 CURR PIREG P GAINSCALE 0 DEC 1000 CURR PIREG I GAIN 128 DEC 1000 ff CURR_PIREG_I_GAINSCALE 0 DEC 1000 PER T ALIGN 5 486 4 ms 1000 commands StartStop bit BIN 500 xl Done COMM speed 9600 bps modify variables here Figure 6 10 PC Master Software Parameters Tuning Control Window Start the PC master software parameters tuning application Designer Reference Manual DRMO28 Rev 0 130 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor oldc_zerocrosO8MR32 pc_master tuning_bldc pmp After you start the PC master software you can choose which parameters you are going to tune current start up speed parameters see Figure 6 10 Then you can press control page to make the control window visible and provide control in the same way as in PC Master Software Remote Operating Mode Or you can display the oscilloscope window see Figure 6 11 You can then modify the variable values in the variable window Figure 6 11 which is visible for both control page or oscilloscope page turned on The variables can be modified according to their defined limits Bi xd File Edit View Scope Item Project Help 4 4 BY Tahoma x 8 u elel JE a aaa gu pe i 221 3ph BLDC motor on HCOSMR32 EMS 1 Cu
22. DRMO28 Rev 0 156 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor Range lt 1 255 gt The final PWM period is defined by setting SET PER PWM The PWM period us is PWM period PERIOD US SET PER PWM 2 EQ 6 14 With default software setting oscillator clock etc The final PWM frequency Hz is 10 PWmMfrequency Seer PER PWM EQ 6 15 With default software setting Settings for some important PWM frequencies are listed in Table 6 3 Table 6 3 PWM Frequency Setting SET PER FREQUENCY PWM PERIOD PWM US 16 0 31 250 Hz 32 us 25 0 20 000 Hz 50 us 32 0 default 15 625 Hz 64 us 128 0 3 90625 Hz 256 us CAUTION Current measurement sampling period is synchronized with PWM Therefore changing PWM frequency automatically changes the current sampling period This apart from other things effects the current regulator Therefore after changing PWM frequency changing or checking current sampling period is strongly recommended 6 5 7 2 Current Sampling Period Current sampling period should usually be changed in two cases 1 When PWM frequency is changed 2 Motors with externally low electrical constant If the motor electrical constant is lower than default current sampling period of 128 us the current regulator may not work properly DRMO
23. Evaluation Motor Hardware Set Configuration 6 4 1 3 Low Voltage Hardware Set Configuration The system configuration for low voltage hardware set is shown in Figure 6 3 DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 115 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc PC Computer RS232 40w flat PC Master U2 ribbon U1 cable 3ph AC BLDC lind Low Voltage Controller Board GND Power Stage HC908MR32 12VDC ECLOVACBLDC ECCTR908MR32 m T ETT M40 rl npe 9 lt KITMMDSO8MR32 ats ECMTRLOVBLDC PC Computer Not Connected Not Connected RS232 emulator Figure 6 3 Low Voltage Hardware System Configuration NOTE _ All the system parts are described in section Section 4 Hardware Design They can be ordered as a standard products For the the supply and in detail document references shown see section 4 2 3 Low Voltage Hardware Set Configuration 6 4 1 4 Controller Board Settings Controller board settings are the same for all hardware platforms Jumpers JP3 and JP7 must be connected with the other jumpers disconnected See Figure 6 4 Designer Reference Manual DRMO28 Rev 0 116 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Application Hardware and Software Configuration a am oa OF Ne b
24. Go to www freescale com Freescale Semiconductor Inc Software Design Main Software Flowchart 3 2 5 Back EMF Sensing Circuit The zero crossing selection is provided by the multiplexer setting As shown in Figure 5 2 the commutation and back EMF zero crossing selection process is split into two actions e Preset commutation and zero crossing selection The preset means setting the buffered registers and RAM variables for commutation e Set commutation and zero crossing selection The setting means loading the registers with buffered variables The implementation is described in Implementation Notes 5 6 2 BLDC Commutation and Zero Crossing Selection 5 4 Main Software Flowchart DRMO028 Rev 0 The main software flowchart incorporates the main routine entered from the reset and interrupt states The main routine includes initializing the MCU and the main loop The flowcharts are shown in Figure 5 4 Figure 5 5 and Figure 5 6 MCU Initialization is entered only after system reset It provides initialization of system registers ports and CPU clock The MCU Initialization is provided in MCUInit function After MCU Initialization the Application Initialization is executed as Appinit function which performs the following actions First the zero current offset of the dc bus current measurement path is calibrated This offset on the ADC input should be 1 65 V at zero current This is implemented in the hardware de
25. Hardware and Software Configuration 113 Tuning for Customer 126 Appendix A References Appendix B Glossary DRMO28 Rev 0 8 MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control DRM028 Rev 0 List of Figures Figure Title Page 2 1 System 16 3 1 BLDC Motor Cross 1 24 3 2 3 Phase Voltage System 24 3 3 BLDC Motor Back and Magnetic Flux 26 24 Classical 2 27 3 5 Power Stage Motor Topology 28 3 6 Phase Voltage 31 3 7 Mutual Inductance 32 3 8 Detail of Mutual Inductance 33 3 9 Mutual Capacitance 34 3 10 Distributed Back EMF by Unbalanced Capacity COUPIO ita viene 35 3 11 Balanced Capacity 36 3 12 Back EMF Sensing Circuit 37 3 13 The Zero Crossing Detection 38 3 14 Commutation Control 5 39 d AINME minannar a PADOS n REEE
26. MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control Section 2 System Description 2 1 Contents 2 2 System 15 20 System Specification 17 2 2 System Concept The application block diagram is shown in Figure 2 1 The sensorless rotor position technique detects the zero crossing points of back EMF induced in the motor windings The phase back EMF zero crossing points are sensed while one of the three phase windings is not powered The information obtained is processed in order to commutate the energized phase pair and control the phase voltage using pulse width modulation The back EMF zero crossing detection enables position recognition The resistor network is used to step down sensed voltages to a 0 3 3 V level Zero crossing detection is synchronized with the middle of center aligned PWM signals by the software in order to filter high voltage spikes produced by switching the IGBTs MOSFETs The software selects by MUX command the phase comparator output that corresponds to the current commutation step The multiplexer MUX circuit selects this signal which is then transferred to the MCU input The voltage drop resistor is used to measure the dc bus current which is chopped by the pulse width modulator PWM The signal obtained
27. Minimal Voltage Limits Setting under a different label CAN CHANGE 1 6 5 3 4 Current Setting Hardware Customizing Maximal measurable current determined by hardware current sensing A MUST IF HW CHANGE 4 define CURR HW MAX A 2 93 Range O infinity DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 135 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Minimal measurable current determined by hardware current sensing A MUST IF HW CHANGE 5 define CURR HW MIN A 2 93 Range infinity O gt CURR_HW_MAX_A and CURR_HW_MIN_A must be changed when current sensing range is different from default hardware Maximal limit of dc bus current allowable for the hardware A MUST IF HW CHANGE 6 define CURR MAX FAULT A 1 5 Range 0 CURRENT RANGE MAX A CURR MAX FAULT A determines the maximal current when the drive fault state should be entered So it must be set to the maximum current allowed for the power stage or the motor see also Maximal and Minimal Current Limits Setting 6 5 3 5 Example of Software Customizing to Hardware Let s have low voltage power stage ECLOVACBLDC modified to 42 V from 12 V as described in its documentation So software must be customized for hardware changes Because of low voltage set the const cust lv h must be modified 1 Designer Reference Manual Maximal PWM duty cycle remains the same
28. OR PCMODE amp CLEARFAIL FAILURE 0 OR RESET Figure 5 13 Fault State 5 6 Implementation Notes 5 6 1 Software Files The software files and structure are described in section 6 4 2 1 Application HC08 Software Files DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 103 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design 5 6 2 BLDC Commutation and Zero Crossing Selection The required BLDC motor voltage system commutation is provided using the MC68HCO8MR32 PWM block The zero crossing selection is provided by setting port F pins PTF1 PTF3 connected to the multiplexer As shown in Data Flow the commutation and back EMF zero crossing selection process is split into two actions 1 Preset BLDC commutation and BEMF zero crossing selection 2 Set BLDC commutation and BEMF zero crossing selection 5 6 2 1 Preset BLDC Commutation and BEMF Zero Crossing Selection In each phase of the 6 step commutation two PWM channels bottom and top switch are active and the other four PWM channels are logical 0 The commutation preset is accomplished by setting the buffered registers PVAL1H PVAL1L through PVAL6H PVALE6L To preset the active PWM channel the MSB bits of the dedicated PVALXH registers are set to 0 To preset the PWM channel to the logical 0 the MSB bits of the dedicated PVALXH registers are set to 1 This is due to the signature bit fu
29. On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design System Configuration and Documentation PC Computer RS232 40w flat PC Master U2 ribbon U1 cable 3ph AC BLDC lind Low Voltage Controller Board GND Power Stage HC908MR32 12VDC ECLOVACBLDC ECCTR908MR32 m T ETT M40 re 9 lt KITMMDSO8MR32 ate ECMTRLOVBLDC PC Computer Not Connected Not Connected RS232 emulator Figure 4 3 Low Voltage Hardware System Configuration All the system parts are supplied and documented according to the following references e EVM1 Modular Development System with EM08MR32 Daughter Board Supplied as KITMMDSO08MR32 Described in Manual supplied with kit e 01 Controller Board for MC68HC908MR32 Supplied as ECCTR908MR32 Described in MC68HC908MR3 2 Control Board User s Manual Motorola document order number MEMCMR32CBUM D see References 3 e U2 3 Phase AC BLDC Low Voltage Power Stage Supplied as ECLOVACBLDC DRMO028 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 63 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design Described in Motorola Embedded Motion Control 3 Phase BLDC Low Voltage Power Stage User s Manual Motorola document order number MEMC3PBLDCLVUM D3 see References 7 MB1 Motor Brake SM40N SG40N S
30. Rev 0 Designer Reference Manual MOTOROLA Introduction 13 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Introduction Once using the semiconductor components it is opened to replace classical universal and DC motors with maintenance free electrically commutated BLDC motors This brings many advantages of BLDC motors when the system costs could be maintained equivalent The advantages of BLDC motor versus universal and DC motors are high efficiency e reliability no brushes low noise easy to drive features To control the BLDC motor the rotor position must be known at certain angles in order to align the applied voltage with the back EMF which is induced in the stator winding due to the movement of the permanent magnets on the rotor Although some BLDC drives uses sensors for position sensing there is a trend to use sensorless control The position is then evaluated from voltage or current going to the motor One of the sensorless technique is sensorless BLDC control with back EMF electromotive force zero crossing sensing The advantages of this control are e Save cost of the position sensors amp wiring e be used where there is impossibility or expansive to make additional connections between position sensors and the control unit Low cost system medium demand for control MCU power Designer Reference Manual DRMO28 Rev 0 14 Introduction
31. Routine Explained in 5 5 5 Back EMF Acquisition State Error Handler Explained in 5 5 5 Back EMF Acquisition State Over Current Explained in 5 5 5 Back EMF Acquisition State Designer Reference Manual DRMO28 Rev 0 100 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design State Diagram MOTOR STOP IS REQUIRED T3 TIME OUT DIS SPEED CONTROL T8 F 1 CURRENT MEASUREMENT IS DONE DONE P etia MEASUREMENTS F 1 HANDLER DONE ERROR HANDLER B DONE PHASE HAS BEEN COMMUTATED PC F 1 RECEIVED THE ZERO CROSSING EVENT ICRF 1 DONE DONE SERVICE OF COMMUTATION SERVICE OF RECEIVED BACK EMF ZERO CROSSING FEEDBACK IRRECOVERABLE COMMUTATION ERROR OVER CURRENT TIMER2 TIM A CH3 INTERRUPT P il PWM RELOAD INTERRUPT PWM CENTER DONE De ene BEMF ZERO CROSSING SENSING ISR PHASE HAS BEEN TIMER1 TIM A CH1 INTERRUPT COMMUTATED PC_F 1 CURRENT MEASUREMENT ICR F 1 IS DONE CURRENT MEASUREMENT CMD F 1 ISR gt Figure 5 11 Running State DRM028 Rev 0 Designer Reference Manual MOTOROLA Software Design 101 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design 5 5 7 Stop State When motor stop is required the PWM signals are disabled and the power switches are switched o
32. State 3 3 1 5 Starting Commutation Time Calculation Even the sub states of the commutation process in the starting back EMF acquisition state remain the same as in the running state The required commutation timing depends on application state starting state running state So the commutation time calculation is the same as that described in Running Commutation Time Calculation but the following computation coefficients are different coefficient Coef HlfCmt 0 125 with advanced angle Advance angle 60Deg 3 8 22 5Deg at Starting state DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 49 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control 3 3 2 Speed Control Coef Toff 0 5 at Running state Per Dis 150 with default s w setting The speed close loop control is provided by a well known PI regulator The required speed is calculated from speed input variable as explained in Process Desired Speed Setting The actual speed is calculated from the average of two back EMF zero crossing periods time intervals received from the sensorless commutation control block The speed regulator output is a PWM duty cycle The speed controller works with the constant execution sampling period PER_T3_RUN_US A detailed explanation is provided in Processs Speed Control 3 4 Application Control The application can be controlled in two
33. T2 US Usually it is not recommended to change PER CMT MAX US The change is only necessary if the commutation period at start up is to long Alignment to Start Increment of the regulators output CAN CHANGE 7 EXPER define START INCR OOUTREG 20 0 Range 128 127 Designer Reference Manual DRMO28 Rev 0 146 User Guide For More Information On This Product Go to www freescale com MOTOROLA 28 Rev 0 Freescale Semiconductor Inc User Guide Tuning for Customer Motor START_INCR_OOUTREG should not necessarily be changed for a motor accommodation It can be set experimentally If the motor has a low torque increase the value If the motor starts with a high speed then slows down by regulator decrease the value START_INCR_OOUTREG can be evaluated with PC master software tuning file tuning_bldc pmp Number of successive feedbacks necessary to enter the Running state CAN CHANGE 8 EXPER define I_CNTR_FOK 0x03 Range lt 0 255 gt The motor starts spinning with Starting Back EMF Acquisition state The software enters regular Running state with speed regulation after CNTR FOK back EMF successive commutation steps are done Usually it is not recommended to change I CNTR FOK but it can be evaluated when there are problems with motor start up I CNTR FOK can be evaluated with PC master software tuning file uning bldc pmp
34. We suggest using PC master software with tuning file tuning bldc pmp for start up parameters evaluation You can use this procedure 1 Ensure that the Alignment current and regulator were properly set Alignment Current and Current Regulator Setting 6 5 4 3 in const cust x h 2 Ensure that PER DIS US and COEF HLFOCMT are properly set in const cust x h 3 Set define PER CMT START US in const cust x h according to Table 6 2 4 Ensure PER CMT START US PER CMT MAX US 2 5 Set define START INCR OOUTREG 20 0 in const cust x h 6 In order to disable speed regulator temporarily change the software by clearing speed regulator parameters 7 define SPEED PIREG P GAIN 0 64 Designer Reference Manual MOTOROLA User Guide 147 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc define SPEED_PIREG_ _ GAIN 8 in const cust x h file 9 Build and run the code see Software Execution Build and Execute from Evaluation Board 10 Start the PC master software tuning project 11 Select Start Parameters Tuning subproject see Software Parameters Tuning with PC Master Software Project File in order to be able to modify the start parameters 12 You can see the actual zero crossing commutation period on the Start Parameters Tuning New Scope or measure the phase a b and c voltages on a real oscilloscope Designer Reference Manual DRMO28 Rev 0 148 User Guide MO
35. basic modes e Manual mode e PC master software mode In manual mode it is controlled by an on board start stop switch and speed potentiometer In PC master mode it is controlled from a computer using PC master software In both modes the individual variables can be observed using the PC master software 3 4 1 PC Master Software Designer Reference Manual PC master software was designed to provide the debugging diagnostic and demonstration tools for developing algorithms and applications It consists of components running on PCs and parts running on the target MCU connected by an RS232 serial port A small program is resident in the MCU that communicates with the PC master software to parse commands return status information and process control information from the PC The PC master software uses Microsoft Internet Explorer as a user interface on the PC DRMO28 Rev 0 50 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Application Control 3 4 1 1 Communication with PC Master Software Specifications SCI communication protocol with a default of 9 6 Kbaud is used for communication as described in User s Manual for PC Master Software Motorola 2000 found on the World Wide Web at http e www motorola com PC master software controls and senses the status of the application with PC master software BLDC dem
36. commutation time is defined by the start commutation period Per CmtStart This allows starting the motor such that minimal speed defined by state when back EMF can be sensed and is achieved Designer Reference Manual MOTOROLA BLDC Motor Control 45 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Designer Reference Manual during several commutations while producing the required torque Until the back EMF feedback is locked the commutation process explained in Running assures that commutations are done in advance so that successive back EMF zero crossing events are not missed After several successive back EMF zero crossings e Exact commutation time can be calculated e Commutation process is adjusted e Control flow continues to the Running state The BLDC motor is then running with regular feedback and the speed controller can be used to control the motor speed by changing the PWM duty cycle value DRMO28 Rev 0 46 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Used Control Technique MOTOR IS RUNNING MOTOR IS STARTING AT STEADY STATE CONDITION WITH REGULAR BACK EMF FEEDBACK STATOR ROTOR MAGNETIC a FIELD CREATED BY x ALIGNMENT STATE The rotor position is stabilized by BORDER OF applying PWM signals to on
37. desired speed held in register Speed Desired is calculated from the following formula Speed Desired Sp Input Coef Speed Inp 255 Speed Min U8 5 3 8 Processs Speed Control The general principle of the speed PI control loop is illustrated in Figure 5 3 REFERENCE PWM SPEED SPEED DUTY CYCLE Speed Desired ERROR PI OutReg_U8 CONTROLLED R M CONTROLLER SYSTEM ACTUAL MOTOR SPEED 256 Per Speed MAX Range Per ZCrosFIt T2 Figure 5 3 Closed Loop Control System The speed closed loop control is characterized by the feedback of the actual motor speed The actual motor speed is calculated from zero crossing period Actual motor speed 256 Per Speed MAX Range Per ZCrosFIt T2 DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 81 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design This information is compared with the reference set point and the error signal is generated The magnitude and polarity of the error signal corresponds to the difference between the actual and desired speeds Based on the speed error the PI controller generates the corrected motor voltage in order to compensate for the error The speed regulator parameters gain internal and input output variables are located in the structure PIParamsScl_U8_ Speed The speed controller works with a constant execution sampling period T
38. drive is controlled remotely from a PC through the serial communication interface SCI channel of the MCU device via an RS 232 physical interface The drive is enabled by the RUN STOP switch which can be used to safely stop the application at any time For the PC master software remote control it is necessary to have PC master software installed on your PC computer Start the PC master software application oldc_zerocrosO8MR32 pc_master BLDC pmp After you start the PC master software press control page to make the control window visible Figure 6 6 illustrates the PC master software Control Window DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 123 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc After you start the PC master software the algorithm block description window appears instead of the PC master control window therefore press control page If the PC master software project pmp file is unable to control the application it is possible that the wrong load map bin bldc_zerocros0O amp mr32_MMDS map file has been selected PC master software uses the load map to determine addresses for global variables being monitored Once the PC master project has been launched this option may be selected in the PC master window under Project Select Other Map FileReload Ef BLDC pmp PCMaster l x Fil
39. increase or decrease by PC master software 16 Repeat step 15 until the motor starts well If the motor starts against a high start up torque or if Alignment state current is low DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 149 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 20 21 it is recommended to change START_INCR_OOUTREG by PC master software If it is a problem to start the motor then CNTR FOK can also be changed from default 0x03 but not recommended If the motor starts and continues running after you repeatedly start stop the start up parameters are set properly Open const cust x h and modify parameters with the final variable values PER CMT START US START INCR OOUTREG evaluated with PC master software Change the software back to normal set speed regulator parameters to define SPEED PIREG GAIN 64 define SPEED PIREG GAIN 0 in const cust x h file to enable speed regulation Build the code see Software Execution and Build 6 5 6 Software Customizing to Motor Speed Control Setting When the motor commutation setting is done the speed control parameters need to be set For settings which must be done follow the labels MUST CHANGE nn MUST CHANGE EXPER file const cust x h For changes which can be done but usually are not necessary follow the labels CAN CHANGE nn CAN CHANGE EXPER file
40. is limited at Per Cmt Max Service of received back EMF zero crossing The commutation time T2 n is evaluated from the captured back EMF zero crossing time T ZCros n Per ZCros n T ZCros n T ZCros n 1 T ZCros n T ZCrosO Per ZCrosFlt n 1 2 Per 7 1 2 ZCrosO HlfCmt n 1 2 Per ZCrosFlt n l Advance angle 1 2 Per ZCrosFlt n C CMT ADVANCE Per ZCrosFlt n Coef HlfCmt Per ZCrosFlt n DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 43 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control The best commutation was get with Advance_angle 60Deg 1 8 7 5Deg which means Coef HlfCmt 0 375 at Running state with default s w setting Per Toff n 1 Per ZCrosFlt Coef Toff and Per Dis minimum Coef Toff 0 375 at Running state Per Dis 150 with default s w setting Per ZCrosO Per ZCros n T ZCrosO T ZCros n T2 n T ZCros n HlfCmt n e fnoback EMF zero crossing was captured during preset commutation period T2P n then Corrective Calculation 1 is made T ZCros n CmtT n 1 Per ZCros n T ZCros n T ZCros n 1 T ZCros n T ZCrosO Per ZCrosFlt n 1 2 Per ZCros n 1 2 Per ZCrosO HlfCmt n 1 2 Per ZCrosFlt n l Advance angle Coef HlfCmt Per ZCrosFlt n The best commutation was get with Advance angle 60Deg 1 8 7 5Deg which means Coef HlfCmt 0
41. stage It supports a wide variety of algorithms for both ac induction and brushless dc BLDC motors Input connections are made via 40 pin ribbon cable connector J14 Power connections to the motor are made on output connector J13 Phase A phase B and phase C are labeled PH_A Ph_B and Ph_C on the board Power requirements are met with a single external 140 to Designer Reference Manual DRM028 Rev 0 66 Hardware Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design High Voltage Hardware Set Components 230 volt dc power supply or an ac line voltage Either input is supplied through connector J11 Current measuring circuitry is set up for 2 93 amps full scale Both bus and phase leg currents are measured A cycle by cycle over current trip point is set at 2 69 amps The high voltage ac power stage has both a printed circuit board and a power substrate The printed circuit board contains IGBT gate drive circuits analog signal conditioning low voltage power supplies power factor control circuitry and some of the large passive power components All of the power electronics which need to dissipate heat are mounted on the power substrate This substrate includes the power IGBTs brake resistors current sensing resistors a power factor correction MOSFET and temperature sensing diodes Figure 4 5 shows a block diagram
42. the PWM period in order to synchronize the current measurement with PWM Current controller period n PWM frequency The BLDC motor rotor position with flux vectors during alignment is shown in Figure 3 15 VCC Alignment flux vector Phase A N Phase B Phase C S VCC Starting flux vector Figure 3 15 Alignment 3 3 1 2 Running The commutation process is a series of states which assure The back EMF zero crossing is successfully captured The new commutation time is calculated The commutation is performed The following processes need to be provided Designer Reference Manual DRMO28 Rev 0 40 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com DRM028 Rev 0 Freescale Semiconductor Inc BLDC Motor Control Used Control Technique BLDC motor commutation service e Back EMF zero crossing moment capture service e Calculation of commutation time e Interactions between these commutation processes From diagrams an overview of how the commutation works can be understood After commuting the motor phases there is a time interval Per_Toff n when the shape of back EMF must stabilized after the commutation the fly back diodes are conducting the decaying phase current therefore sensing of the back EMF is not possible Then the new commutation time T2 n is preset The new commutation will be performed at this time if the back EMF zero cr
43. the phase to phase back EMF crosses zero The motor drive model consists of a normal 3 phase power stage plus a brushless dc motor Power for the system is provided by a voltage source Six semiconductor switches yp controlled elsewhere allow the rectangular voltage waveforms see Figure 3 2 to be applied The semiconductor switches and diodes are simulated as ideal devices The natural voltage level of the whole model is put at one half of the dc bus voltage This simplifies the mathematical expressions Designer Reference Manual DRMO28 Rev 0 28 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Brushless DC Motor Control Theory 3 2 4 1 Stator Winding Equations The BLDC motor is usually very symmetrical All phase resistances phase and mutual inductances flux linkages can be thought of as equal to or as a function of the position with a 120 displacement The electrical BLDC motor model then consists of a set of the following stator voltage equations EQ 3 1 Usa sa Ysa d Rslisp tH Psp EQ 3 1 Usc Yso The task of this section is to explain the background of the back EMF sensing and to demonstrate how the zero crossing events can be detected Parasitic effects that negatively influence the back EMF detection are discussed and their nature analyzed 3 2 4 2 Indirect Back EMF Sensin
44. to modify the current regulator 6 Youcan see the actual current and required alignment current DRMO28 Rev 0 140 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor on the Current Parameters Tuning New Scope or measure the powered motor coil current on real oscilloscope 7 Set PC master software control mode and start the motor see Application Control and PC Master Software Remote Operating Mode If tuning_bldc pmp PCMaster E lel xl File Edit View Scope Item Project Help se e 20 e pps ae a CB zl elel E E 8 3ph BLDC motor on HCOSMR32 EMA 1 Current Parameters Tuning Actual Current CURR_ALIGN_A f Click here for Current Parameters Tuning control page TTTT TTTT TTTT TTTT TTTTTTTTT click here display oscilloscope TT TTTT 516600 516650 516700 516750 516800 515850 516900 516950 Time ms Name ER Value Unit 01 PCMasterMode ALIGN A 1 0 485322 CURR HW MAX 02 command 010 Actual Current 0 0118371 CURR Hw MAX A 02 ManualMode CURR PIREG P GAIN DEC PIREG P GAINSCALE DEC PIREG I GAIN DEC CURR PIREG I GAINSCALE DEC PER T ALIGN MS ms commands StartStop BIN Done COM4 speed 9600 bps Scope Bad
45. which may be encountered when tailoring application using customer motor 6 2 1 Minimal Application Speed NOTE DRMO028 Rev 0 As it is known the back EMF voltage is proportionally dependent on motor speed Since the sensorless back EMF zero crossing sensing technique is based on back EMF voltage it has some minimal speed limitations The motor start up is solved by starting back EMF acquisition state but minimal operation speed is limited The minimal speed depends on many factors of the motor and hardware design and differs for any application This is because the back EMF zero crossing is disturbed and effected by the zero crossing comparator threshold as explained below and in the sections 6 2 4 2 Effect of Mutual Inductance and 6 2 4 1 Effect of Mutual Phase Capacitance Usually the minimal speed for reliable operation is from 7 to 20 of the motor s nominal speed Designer Reference Manual MOTOROLA User Guide For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 6 2 2 Maximal Application Speed NOTE The maximal motor speed is limited by the minimal commutation period 6 maximal speed rpm mi commutation parlod LS GOMMUT REV EQ 6 1 COMMUT REV commutations per motor revolution must be set according to rotor poles COMMUT REV 5 EQ 6 2 where p rotor poles The minimal commutation period is determined by execution time of the soft
46. 028 Rev 0 Designer Reference Manual MOTOROLA User Guide 157 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc For current sampling period setting follow the label CAN CHANGE PERCURSAMP n in const h file Current sampling period setting is provided by CAN CHANGE FPWM n CAN CHANGE PERCURSAMP n define SET PER CS 2 0 Range lt 1 gt The final current sampling period us is Current sampling period PWM period SET PER CS EQ 6 16 current sampling period PWM period SET PER CS us PER CS T1 US PERIOD PWM US SET PER CS us 6 5 7 3 Current Sampling Instant Time period from a PWM reload event middle of central aligned PWM to current sampling time shift of A D conversion with PWM us CAN CHANGE PERCURSAMP n define PER CS US 5 0 Range PERIOD PWM US 2 PERIOD PWM US 2 Usually it is not recommended to change PER PWM CS US butit can be evaluated when there are problems with back EMF zero crossing noise It is necessary to set SET PER CS according to the following equation PERIOD PWM US 2 PERIOD PWM US lt PER PWM CS US lt 2 EQ 6 17 6 5 8 Conclusion Software Parameters Setting and Tuning If all the points in Tuning for Customer Motor are done the software should be customized to customer motor If the software customizing of your motor was not successful it is recommended that you read Application S
47. 10 270 330 Figure 3 2 3 Phase Voltage System The easy to create rectangular shape of applied voltage ensures the simplicity of control and drive But the rotor position must be known at certain angles in order to align the applied voltage with the back EMF voltage induced due to movement of the PM The alignment between Designer Reference Manual DRM028 Rev 0 24 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com DRM028 Rev 0 Freescale Semiconductor Inc BLDC Motor Control Brushless DC Motor Control Theory back EMF and commutation events is very important In this condition the motor behaves as a dc motor and runs at the best working point Thus simplicity of control and good performance make this motor a natural choice for low cost and high efficiency applications Figure 3 3 shows a number of waveforms e Magnetic flux linkage e Phase back EMF voltage e Phase to phase back EMF voltage Magnetic flux linkage can be measured However in this case it was calculated by integrating the phase back EMF voltage which was measured on the non fed motor terminals of the BLDC motor As can be seen the shape of the back EMF is approximately trapezoidal and the amplitude is a function of the actual speed During speed reversal the amplitude changes its sign and the phase sequence changes Designer Reference Manual MOTOROLA BLDC Motor Control 25 For More Inform
48. 3 5 Simple comparison of these two levels can provide the required zero crossing detection As shown in Figure 3 5 the branch voltage of phase B can be sensed between the power stage output B and the zero voltage level Thus back EMF voltage is obtained and the zero crossing can be recognized When Lep Lap this general expressions can also be found uy backup Where EQ 3 7 There are two necessary conditions which must be met Top and bottom switches in diagonal have to be driven with the same PWM signal current goes through the non fed phase that is used to sense the back EMF Figure 3 6 shows branch and motor phase winding voltages during a 0 360 electrical interval Shaded rectangles designate the validity of the equation EQ 3 7 In other words the back EMF voltage can be sensed during designated intervals Designer Reference Manual DRMO28 Rev 0 30 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Brushless DC Motor Control Theory uSa EJ Back EMF can be sensed Figure 3 6 Phase Voltage Waveform However simple this solution looks in reality it is more difficult because the sensed branch voltage also contains some ripples 3 2 4 3 Effect of Mutual Inductance As shown in previous equations EQ 3 4 through EQ 3 6 the mutual inductances play an imp
49. 32 Using a real time debugger supplied with the Metrowerks compiler the evaluation board is connected to the controller board ECCTRMR32 via an emulator connector This solution is recommended for software evaluation 2 Programmed MCU MC68HC908MR32 Where a daughter board module with MC68HC908MR32 processor is plugged into the controller board ECCTRMR32 instead of the emulator cable the processor must be programmed in an external programmer This solution is recommended for final tests Figure 6 1 Figure 6 2 and Figure 6 3 show the configuration with MMDS evaluation board All the system parts are described in Section 4 Hardware Design They can be ordered as a standard products For the the supply and in detail document references see Section 4 Hardware Design Designer Reference Manual MOTOROLA User Guide 113 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 6 4 1 1 High Voltage Hardware Set Configuration The system configuration for a high voltage hardware set is shown in Figure 6 1 12VDC PC Computer RS232 GND PC Master 40w flat ribbon cable 40w flat ribbon cable 3ph AC BLDC High Voltage Power Stage Controller Board HC908MR32 ECCTR908MR32 Optoisolation Board ECOPT 100 240VAC 49 61 Hz ECOPTHIVACBLDC KITMMDS08MR32 ECMTRHIVBLDC PC Computer Not C
50. ABLED RUN CONDITION START SWITCH IS ON AND PCMode 0 OR PCMode AND StartCtrl AND SWITCH IS ON Stop F 0 CLEAR FAILURE START SWITCH SET OFF OR PCMode AND CLEAR FAIL ALIGN STATE FAILURE 0 PWM ENABLED OVER CURRENT ai TIMEOUT EXPIRED FAULT STATE PWM DISABLED IRRECOVERABLE COMMUTATION ERROR BACK EMF ACQUISITION STATE COMMUTATION PWM ENABLED COMMUTATION IS LOCKED WITH BACK EMF FEEDBACK RUNNING STATE OVER VOLTAGE COMMUTATION PWM ENABLED STOP STATE MOTOR STOP IS REQUIRED PWM DISABLED Stop F 1 DONE Figure 5 7 Application State Transitions Designer Reference Manual DRMO28 Rev 0 90 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design State Diagram 5 5 1 Initialize MCU This state is entered after the MCU is reset and performs the following actions e MCU ports are configured for the application e Some application system variables are initialized e MCU clock PLL is locked e Hardware boards used are identified and parameters initialized e PC master communication software is initialized with SCI port e ADC is initialized and the state is exited 5 5 2 Initialize Application This state is used as an application reset called following a return from fault or stop states In this state the following actions are done e Current measureme
51. C Commutation with Back EMF Zero Crossing Sensing Flowchart 3 8 1 8 Running Commutation Time Calculation Designer Reference Manual Commutation time calculation is shown in Figure 3 17 DRMO28 Rev 0 42 BLDC Motor Control For More Information On This Product Go to www freescale com MOTOROLA Freescale Semiconductor Inc BLDC Motor Control Used Control Technique T_Cmt n 2 T Cmt n 1 T Cmt n T2 n 3 T2 n 2 T2 n 1 T2 n n 2 n 1 n Y 2 Per ZCrosFlt n 1 Y Y ee R COMMUTATION IS PRESET ZERO CROSSING COMMUTATED AT PRESET TIME NO DETECTION SIGNAL BACK BMF FEEDBACK WAS RECEIVED CORRECTIVE CALCULATION 1 ra gt T_Cmt n 1 ZERO CROSSING DETECTION SIGNAL BACK EMF FEEDBACK RECEIVED AND EVALUATED gt lt T ZCros n 1 T ZCrosI n Per ZCrosO n Per ZCros n 2 Per ZCros n 1 Per ZCros n Per HlfCmt n Per Toff n T_Cmt n 1 Y COMMUTATED WHEN BACK EMF ZERO CROSSING ZERO CROSSING IS MISSED DETECTION SIGNAL BEST CORRECTION CALCULATION 2 Per 2 Per HlfCmt n a gt lt Figure 3 17 BLDC Commutation Time with Zero Crossing Sensing The following calculations are made to calculate the commutation time T2 n during the Running state e Service of commutation The commutation time T2 n is predicted T2 n T Cmt n 2 Per ZCrosFlt n 1 If 2 Per ZCrosFlt Per Cmt Max then result
52. CCELERATION ZERO CROSSING SENSING Only when regular eedback can not A be used T_ZCros COMMUTATION HAS BEEN PERFORMED FLAG E PC Speed Desired PlParamsScl U8 Speed PROCESS COMUTATION TIMES CALCULATION T2 TIMER 2 Per_Speed_MAX_Range Per ZCrosFIt PROCESS PRESET COMMUTATION AND ZERO CROSSING PROCESS SPEED CONTROL PWM MODULE VIRTUAL TIMER 3 V TASC2 TIMER2 TIMEOUT B PROCESS ACTUAL TIME SET COMMUTATION AND PROCESS ALIGNMENT CONTROL ZERO CROSSING SELECTION TIMER1 INIT Curr Align BACK EMF PlParamsScl S8 Curr ZERO CROSSING MULTIPLEXER Figure 5 2 Main Data Flow Part 2 Alignment Starting Running Control Designer Reference Manual DRMO028 Rev 0 80 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Data Flow 5 3 6 Process Commutation Time Calculation Corrective Calculation 1 Corrective Calculation 2 These processes provide calculations of commutation time intervals periods Per_ZCros Per_ZCrosFIt from captured time T_Cmt T_ZCros T_ZCros0 and sets Timer 2 with variable T2 These calculations are described in 3 3 1 5 Starting Commutation Time Calculation and 3 3 1 3 Running Commutation Time Calculation 5 3 7 Process Desired Speed Setting The
53. CMTRHIVBLDC The individual modules are described in some sections below More detailed descriptions of the boards can be found in comprehensive User s Manuals belonging to each board References 3 4 5 These manuals are available on on the World Wide Web at http www motorola com The User s Manual incorporates the schematic of the board description of individual function blocks and a bill of materials An individual board can be ordered from Motorola as a standard product DRMO28 Rev 0 60 Hardware Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design System Configuration and Documentation 4 2 2 Low Voltage Evaluation Motor Hardware Set Configuration The system configuration for a low voltage evaluation motor hardware set is shown in Figure 4 2 PC Computer RS232 PC Master 40w flat ribbon cable 12 GND Evaluation Motor Board Controller Board HC908MR32 12VDC ECCTR908MR32 M1 ECMTREVAL KITMMDSO8MR32 IB23810 PC Computer RS232 emulator Figure 4 2 Low Voltage Evaluation Motor Hardware System Configuration All the system parts are supplied and documented according to the following references e EVM1 Modular Development System with EM08MR32 Daughter Board Supplied as KITMMDSO8MR32 Described in Manual supplied with kit e 01 Controller Board for MC68HC908MR32
54. ED MIN RPM 1000 DEC 1000 DEC DEC DEC SPEED RANGE MAX RPM 1000 1000 1000 0 265625 1000 COMM speed 9600 bps scope Running modify values here Figure 6 14 PC Master Software Speed Parameters Tuning Window Designer Reference Manual 5 Build and run the code see Software Execution Build and Execute from Evaluation Board 6 Start the PC master software tuning project 7 Select Speed Parameters Tuning subproject see Software Parameters Tuning with PC Master Software Project File in order to be able to modify the current regulator 8 You can see the actual speed and desired speed on the Speed Parameters Tuning New Scope or measure the phase voltage period on real oscilloscope DRMO28 Rev 0 154 User Guide For More Information On This Product Go to www freescale com MOTOROLA Freescale Semiconductor Inc 10 18 19 20 21 28 Rev 0 User Guide Tuning for Customer Motor Set PC master software control mode and start motor see Application Control and PC Master Software Remote Operating Mode Set the speed to the middle of minimal and maximal speed Increase step by step the proportional gain SPEED_PIREG_P_GAIN with PC master software until speed noise or oscillation appears or up to 128 If SPEED_PIREG_P_GAIN is set to 128 increase proportional gains in SPEED_PIREG_P_GAINSCALELEFT further with PC master software steps 0 1 2 8 otherwise lea
55. ENT DETECTION b IRRECOVERABLE OVER CURRENT ALIGN TIME OUT EXPIRED TIMER1 TIM A CH1 INTERRUPT CURRENT MEASUREMENT ISR CURRENT MEASUREMENT IS DONE CMD_F 1 DONE Figure 5 9 Align State Scheduler The scheduler handles the state transitions in the align state The dc bus current measurement is done in OC interrupt service routine in order to keep synchronization with PWM cycle After measurement is made the scheduler allows calculation by the current controller and Designer Reference Manual DRMO28 Rev 0 94 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design State Diagram the over current detection The CMD_F current measurement done flag indicates that the new value of dc bus current is ready to be processed by the current controller The time out software timer 3 of this state is defined in the software by the constants PER_T_ALIGN and PER_BASE_T3_ALIGN Current Controller The current controller subroutine is called every PER_CS_T1_US us 128 us with default software setting after a new value of the dc bus current has been obtained CMD_F 1 It sets all six PVALx register pairs to get the right PWM ratio for the required current Timer 1 Interrupt Once the synchronization of OC function with the PWM cycle has been achieved it must be maintained because the current measurement is init
56. Freescale Semiconductor Inc BLDC Motor Control NOTE Designer Reference Manual UVC Cap Figure 3 9 Mutual Capacitance Model Let us focus on the situation when the motor phase A is switched from negative dc bus rail to positive and the phase B is switched from positive to negative This is described by these conditions EQ 3 8 Sap Sg lt PWM 1 1 1 1 Uva 2 gt xe 72d EQ 3 8 lcac lccp lc The voltage that disturbs the back EMF sensing utilizing the free not powered motor phase C can be calculated based the equation 1 1 UyC 5 Uceb FUcac t 2Rc Uce Rc 5 3 9 The final expression for disturbing voltage can be found as follows Mb poa Can Op cap 2 Cac Cop fic 2 Cov Cac EQ 3 10 EQ 3 10 expresses the fact that only the unbalance of the mutual capacitance not the capacitance itself disturbs the back EMF sensing When both capacities are equal they are balanced the disturbances disappear This is demonstrated in Figure 3 10 and Figure 3 11 DRMO28 Rev 0 34 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Brushless DC Motor Control Theory 8 Single 379 2 50MS s ee E Ch Zoom VOX Vert 00 T m TIRE chi 99V HE UV o
57. Freescale Semiconductor Inc le oye MOTOROTA digital dna intelligence everywhere Sensorless BLDC Motor Control Using the MC68HC908MHR32 Designer Reference Manual M68HC08 Microcontrollers DRM028 D Rev 0 03 2003 MOTOROLA COM SEMICONDUCTORS For More Information On This Product o to www freescale com Freescale Semiconductor Inc For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Sensorless BLDC Motor Control Using the MC68HC908MR32 Designer Reference Manual Rev 0 by Libor Prokop Motorola Czech System Laboratories Roznov pod Radhostem Czech Republic DRMO028 Rev 0 Designer Reference Manual MOTOROLA 3 For More Information On This Product to www freescale com Freescale Semiconductor Inc Revision history To provide the most up to date information the revision of our documents on the World Wide Web will be the most current Your printed copy may be an earlier revision To verify you have the latest information available refer to http www motorola com semiconductors The following revision history table summarizes changes contained in this document For your convenience the page number designators have been linked to the appropriate location Revision history Revision mee Page Date Level Description Number s February 2003 1 Initial release N A Designer Reference Manual DRMO28
58. NING CONTROL PROCESS FAULT CONTROL FAULT STOP Volt_Max_Fault Curr_Max_Fault FFLAG1 FFLAG2 Figure 5 1 Main Data Flow Part1 5 3 4 Process Fault Control Fault Stop The process provides fault control and fault stop as described in Fault State Stand By Align State 5 5 5 Back EMF Acquisition State and Running State The processes alignment starting and running control are displayed in Figure 5 2 The processes are described in the following subsections 5 3 5 Process Back EMF Zero Crossing Sensing Back EMF zero crossing process provides e Back EMF zero crossing sampling in synchronization with PWM Designer Reference Manual DRMO28 Rev 0 78 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Data Flow e Evaluates the zero crossing e Records its time in T_ZCros Further explanation is provided in Data Flow and Figure 5 6 DRM028 Rev 0 Designer Reference Manual MOTOROLA Software Design 79 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design TIMER 2 BACK EMF T CMT ACTUAL TIME ZERO CROSSING INPUT Sp_Input Speed_Min_U8 Coef_Speed_Inp PROCESS DESIRED SPEED SETTING V_TASC2 CORRECTIVE CALCULATION 1 OF COMMUTATION PARAMTERS CORRECTIVE CALCULATION 2 PROCESS OF COMMUTATION PARAMETERS BACK EMF A
59. OLO IL ae 15 System 15 System Specification 17 Section 3 BLDC Motor Control da 23 Brushless DC Motor Control 23 Used Control 38 Applicaton DOT aud ace an CA oC JR CR ERE RR 50 Section 4 Hardware Design idk eae ee ee a eee 57 System Configuration and Documentation 57 All HW Sets 64 High Voltage Hardware Set 66 Low Voltage Evaluation Motor Hardware Set Components 70 Low Voltage Hardware Set Components 72 Designer Reference Manual MOTOROLA 7 For More Information On This Product Go to www freescale com Designer Reference Manual Freescale Semiconductor Inc Table of Contents 53 5 2 5 3 5 4 5 5 5 6 6 1 6 2 6 3 6 4 6 5 Section 5 Software Design dlc T Com 75 Lidits Pie MEME Ree ek 75 gt ech 75 Main Software Flowchart 83 State 89 Implementation 103 Section 6 User Guide COMES eedan E a a a 109 Application Suitability 109 O ee A ER A TIT 112 Application
60. PEED REGULATOR CONSTANTS CURR PIREG P GAINSCALELEFT CURR PIREG P GAIN CURR PIREG GAINSCALELEFT PIREG I GAIN Figure 6 7 Follow up for Software Customizing to Customer Motor Designer Reference Manual DRMO28 Rev 0 128 User Guide For More Information On This Product Go to www freescale com MOTOROLA Freescale Semiconductor Inc User Guide Tuning for Customer Motor PWM Frequency and Current Sampling Period Setting SET PWM FREQUENCY SET_PER_PWM SET CURRENT SAMPLING PERIOD SET_PER_CS SET PERIOD FROM PWM RELOAD TO CURRENT SAMPLING SET_PER_CS Figure 6 8 Follow up for Advanced Software Customizing Decision on the Motor Suitability MEASURE FREE PHASE BACK EMF VOLTAGE FOR THE MOTOR MUTUAL CAPACITANCE EFFECT MEASURE FREE PHASE BACK EMF VOLTAGE FOR THE MOTOR INDUCTANCE CAPACITANCE EFFECT Decision on the Application Suitability CHECK MINIMAL APPLICATION SPEED CHECK MAXIMAL MOTOR SPEED Figure 6 9 Follow up for Software Customizing Trouble Shouting 6 5 1 Software Parameters Tuning with PC Master Software Project File Sensorless BLDC software is provided with a PC master software project file for on line software parameters tuning See Figure 6 10 This file supports e Remote application control e Key software parameters modification for Current parameters tuning Start up parameters tuning Speed
61. PIREG P GAIN 0 SPEED PIREG GAINSCALERIGHT 7 SPEED PIREG GAIN 0 3 Ensure that COMMUT REV SPEED RANGE MAX RPM SPEED MAX RPM are set properly in const cust x h 4 Set SPEED MIN RPM as required should be SPEED MIN RPM gt SPEED MAX 5 for reliable commutation at low speed Designer Reference Manual MOTOROLA User Guide 153 For More Information On This Product Go to www freescale com If tuning bldc pmp PCMaster E File Edit view Scope Item Project Help Freescale Semiconductor Inc 18 x 8 3ph BLDC motor on HCOSMR32 H um 1 Current Parameters Tuning New Scope 2 Start Parameters Tuning New Scope al 3 Speed Parameters Tuning New Scope eg IAxis Click here for Speed Parameters Tuning StartStop ClearFail 01 PCMasterMode 02 command 010 02 ManualMode commands 0 9 0 8 0 7 0 6 0 5 04 0 3 e Fe e gt MS s memi sf B z 02 Sp Control SPEED PIREG P GAIN Actual Speed Desired Speed OutReg Integral 1 E E click here to dis r control page click here to display i oscilloscope SPEED_PIREG_P_GAINSCALE SPEED_PIREG_I_GAIN SPEED_PIREG_I_GAINSCALE SPEED_MIN_RPM 14500 14750 15250 15500 Time ms 15750 16000 500 500 COEF_SPEED_INP SPE
62. R define SPEED PIREG P GAIN 128 Range 0 255 where the current regulator proportional gain is SPEED PIREG P GAINSCALELEFT KP SPEED PIREG P GAIN 2 x EQ 6 12 MUST CHANGE 15 EXPER define SPEED PIREG I GAINSCALERIGHT 0 Range 0 8 MUST CHANGE 16 EXPER define SPEED PIREG I GAIN 64 Designer Reference Manual DRMO28 Rev 0 152 User Guide MOTOROLA For More Information On This Product Go to www freescale com DRM028 Rev 0 Freescale Semiconductor Inc User Guide Tuning for Customer Motor Range lt 0 255 gt where the current regulator integral gain is SPEED PIREG I GAINSCALERIGHT KI SPEED PIREG I GAIN 2 EQ 6 13 These constants can be calculated according to regulators theory The speed sampling regulator execution period is PER_T3_RUN_US 2 560 ms at default software setting Another recommended solution is experimental setting SPEED_PIREG_P_GAINSCALELEFT SPEED_PIREG_P_GAIN SPEED PIREG GAINSCALERIGHT SPEED_PIREG_I_GAIN can be evaluated with PC master software tuning file tuning bldc pmp We suggest using PC master software with tuning file tuning bldc pmp for regulator parameters evaluation You can use this procedure 1 Ensure that the start up and commutation parameters were set properly Start up Constants and Maximal Commutation Period 6 5 4 3 in const cust x h 2 Setconst cust x h SPEED PIREG P GAINSCALELEFT 0 SPEED
63. R PIREG I GAINSCALELEFT 0 Range lt 0 8 gt MUST CHANGE 5 EXPER define CURR PIREG I GAIN 64 Range 0 255 where the current regulator integral gain is KP CUR PIREG 1 GAIN 2CURR PIREG 1 GAINSCALELEFT EQ 6 5 These constants can be calculated according to regulators theory The current sampling regulator execution period is PER CS T1 US 128 us at the default software setting Normally it does not need to be changed if change is required see PWM Frequency and Current Sampling Period Setting Another recommended solution is an experimental setting CURR PIREG P GAINSCALELEFT CURR PIREG P GAIN PIREG GAINSCALELEFT CURR 1 GAIN can be evaluated with PC master software tuning file tuning bldc pmp We suggest using PC master software with tuning file tuning bldc pmp for regulator parameters evaluation You can use this procedure 1 Set const cust x h CURR PIREG P GAINSCALELEFT 0 CURR PIREG P GAIN 0 CURR PIREG GAINSCALELEFT 0 CURR PIREG GAIN 0 2 Temporarily change the software in code start c file label TUNING 1 enable goto Align it will cause infinite time for alignment state where the current is tuned Build and run the code see Software Execution Build Execute from Evaluation Board 4 Start the PC master software tuning project 5 Select Current Parameters Tuning subproject see Software Parameters Tuning with PC Master Software Project File in order to be able
64. RMO28 Rev 0 144 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor In the real system the ZC Cmt angle is a little bit greater than the theoretical calculation This is due to the response time of the hardware back EMF zero crossing sensing Therefore the default software setting is COEF_HLFCMT 0 375 Normally COEF_HLFCMT should only be changed if you need a different commutation angle time from back EMF zero crossing to commutation For example for motor field weakening The relation between COEF_HLFCMT and the commutation can also be defined by Advance_angle which is the electrical angle shift from ideal commutation Advance angle 30 Deg ZC Cmt angle 9 a 4 EQ 6 7 COEF HLFCMT 1 Advance angle 2 Bn EQ 6 8 Advance angle 15 for COEF_HLFCMT 0 25 Advance angle 7 5 for COEF HLFCMT 0 375 Advance angle 0 for COEF_HLFCMT 0 5 The relation between back EMF zero crossing and the commutation is explained in the section 3 3 1 3 Running Commutation Time Calculation 6 5 5 2 Start up Constants and Maximal Commutation Period Constants defining start up need to be changed according to the drive dynamics Start Commutation Period us MUST CHANGE 8 EXPER define PER CMT START US 4000 0 Range 0 PER CMT MAX US 2 PER CMT START USis the period used to calculate the first star
65. ROSSINGS EB d E i po 54 f IDEAL COMMUTATION PATTERN WHEN POSITION IS KNOWN C roe REAL COMMUTATION PATTERN WHEN POSITION IS ESTIMATED zm FIRST SECOND THIRD FOURTH insciis ALIGN STARTING BACK EMF ACQUISITION RUNNING Figure 3 19 Back EMF at Start Up Figure 3 20 illustrates the sequence of the commutations during the starting back EMF acquisition state The commutation times T2 1 and T2 2 are calculated without any influence of back EMF feedback The commutation time calculations are explained in the following section Designer Reference Manual DRMO28 Rev 0 48 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Used Control Technique 1 T cmt 2 T cmt 3 T2 1 T2 2 T2 n n 1 n 2 n 3 Y 2 Per ZCrosFlt n 1 Y pud 2 Per CmtStart COMMUTATION IS PRESET ZERO CROSSING DETECTION SIGNAL COMMUTATED AT PRESENT TIME NO BACK EMF FEEDBACK WAS RECEIVED CORRECTIVE CALCULATION 1 T ZCros 0 T2 n ZERO CROSSING DETECTION SIGNAL CTION SIG COMMUTED WHEN CORRECT BACK EMF FEEDBACK per_HlfCmt n f RECEIVED AND EVALUATED 4 gt T ZCros n T2 n Y ZERO CROSSING ZERO GROSSING IS MESED DETECTION SIGNAL a CORRECTIVE CALCULATION 2 Per Toff n Per HlfCmt n Figure 3 20 Calculation of the Commutation Times During the Starting Back EMF Acquisition
66. Rev 0 132 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor MUST CHANGE nn Label for changes which must be set changed when adapting software for a motor MUST CHANGE nn EXPER Label for changes which must be set changed when adapting software for a motor the setting can be done experimentally MUST IF HW CHANGE nn Label for changes which must be set changed when a power stage board different from high voltage power board is used CAN CHANGE nn Label for changes which can be set changed when adapting software for a motor but usually the setting is not needed CAN CHANGE nn EXPER Label for changes which can be set changed when adapting software for a motor but usually the setting is not needed the setting can be done experimentally 6 5 2 2 Labels in the File const h The other parameters like motor PWM frequency and current sampling period can be set in the file const h The required steps are marked CAN CHANGE FPWM n Label for definitions which should be modified when changing PWM frequency CAN CHANGE PERCURSAMP n ILabel for definitions which should be corrected when changing current sampling period Let s follow the next sections or the labels in the source code to customize the software DRMO028 Rev 0 Designer Reference Manual
67. T X H INTO CODE FUN C FILE Y Y LV for 42V MODIFY R207 R522 R523 R524 SET VOLT HW MAX SET VOLT MAX FAULT V IN CONST CUST LV H FILE SET DUTY PWM MAX SET VOLT HW MAX SET VOLT MAX FAULT V SET CURR HW MAX A SET CURR HW MIN A SET CURR MAX FAULT A IE Voltage and Current Settings SET MAXIMAL FAULT VOLTAGE VOLT MAX FAULT V SET MINIMAL FAULT VOLTAGE VOLT MIN FAULT V SET VOLT 120 THRESHOLD V ONLY FOR HV SET MAXIMAL FAULT CURRENT CURR MAX FAULT A SET NUMBER OF CURRENT FAULTS I CNTR OVC d Alignment Current and Regulator Settings SET ALIGNMENT STATE CURRENT CURR ALIGN A SET CURRENT REGULATOR CURR PIREG P GAINSCALELEFT CURR PIREG P GAIN CURR PIREG GAINSCALELEFT PIREG I GAIN p Start Up Control Settings SET COIL DISCHARGE PERIOD PER DIS US SET COMMUTATION ADVANCING COEFFICIENT COEF HLFCMT SET ALIGNMENT TO START INCREMENT START INCR OOUTREG SET COMMUTATION START PERIOD PER CMT START US AND MAXIMAL PER CMT MAX US SET NUMBER OF SUCCESSIVE BEMF ZERO CROSSINGS TO ENTER RUNNING STATE I CNTR FOK i Speed Control Settings SET COMMUTATIONS PER ROTOR MECHANICAL REVOLUTION COMMUT REV SET MAXIMAL SPEED VARIABLES RANGE SPEED RANGE MAX RPM SET MAXIMAL REQUIRED SPEED SPEED MAX RPM SET MINIMAL REQUIRED SPEED SPEED MIN RPM SET S
68. TOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor If tuning_bldc pmp PCMaster j E l81 xi File Edit View Scope Item Project Help zaop sme asa gj Fe 1e 8 3ph BLDC motor on HCO8MR32 19 1 Current Parameters Tuning pow 2 New Scope ZCros Period IS 2 Start Parameters Tuning Be mA 3 5peeqmarameters Tuning fe Ne pe click here to di Click here for control page Start Parameters Tuning click here to display oscilloscope 22500 22750 23 23250 23500 23750 24000 24250 Time ms Name Period 01 PCMasterMode Startstop 02 command 010 ClearFail b 0 BIN 500 02 ManualMode PER T ALIGN MS 486 4 ms 1000 PER CMT START US 2000 micros 1000 START INCR OOUTREGSS8 5 DEC 1000 I Cntr FOK 3 DEC 1000 ZCros Period 11954 us 100 commands Ready COM4 speed 9600 bps Scope Running modify values here Figure 6 13 PC Master Software Start Parameters Tuning Window 13 Set PC master software control mode see Application Control and PC Master Software Remote Operating Mode 14 Start motor see Application Control and PC Master Software Remote Operating Mode 15 If the software signalizes errors usually commutation error clear the errors stop the motor and change PER CMT START US
69. TOROLA Freescale Semiconductor Inc System Description System Specification The A D converter is also used to sense the dc bus voltage and the drive temperature The dc bus voltage is stepped down to a 3 3 V signal level by a resistor network The six IGBTs copack with built in fly back diode or MOSFETs and gate drivers create a compact power stage The drivers provide the level shifting that is required to drive the high side switch The PWM technique is used to control motor phase voltage 2 3 System Specification The concept of the application is that of a speed closed loop drive using back EMF zero crossing technique for position detection It serves as an example of a sensorless BLDC motor control system using Motorola s MC68HC908MR32 MCU It also illustrates the usage of dedicated motor control on chip peripherals The system for BLDC motor control consists of hardware and software The application uses universal modular motion control development hardware boards which are provided by Motorola for customer development support For a description of these hardware boards refer to Appendix A References 3 4 5 6 7 and the World Wide Web at http www motorola com There are three board and motor hardware sets for the application 1 High Voltage Hardware Set For variable line voltage 115 230 Vac and medium power phase current lt 2 93 A 2 Low Voltage Evaluation Motor Hardware Set For automotive volta
70. TRL FLAG IF RUN CONDITIONS SET STOP_F FLAG YE Stop_F Flag NO DC Bus over voltage SET FAILURE B VOLTAGEFAILURE Stop_F Flag or Failure YES ALIGNMENT STATE TIME ALIGNMENT TIMERS APPLY VOLTAGE CURRENT CONTROL LOOP IF STOP OR FAULT CONDITION STOP MOTOR EXIT RUNNING STATE Stop_F Flag or Failure NO STARTING ACQUISITION STATE PWM INCREMENT OF STARTINCROUTREGS8 SET SPEED REGULATOR INTEGRAL PORTION ACCORDING TO CUR RENT REGULATOR FIRST COMMUTATION STEP SECOND COMMUTATION STEP ACQUISITION STATE MOTOR COMMUTATION LOOP IF ILCNTR_FOK SUCCESSIVE CORRECT COMMUTATIONS EXIT STARTING AQ STATE IF STOP OR FAULT CONDITION STOP MOTOR EXIT RUNNING STATE RUNNING SET TIMER PERIOD FOR SPEED REGULATOR VIRTUAL TIMERS MOTOR COMMUTATION CONTROL LOOP MOTOR SPEED CONTROL LOOP IF STOP OR FAULT CONDITION STOP MOTOR EXIT RUNNING STATE Figure 5 5 Main Software Flowchart Main Software Loop Designer Reference Manual DRMO28 Rev 0 Software Design For More Information On This Product Go to www freescale com MOTOROLA DRM028 Rev 0 Freescale Semiconductor Inc Software Design Main Software Flowchart When the start is successfully completed the Running function is called from main During the Running state the com
71. This Application The brushless dc motor BLDC motor is also referred to as an electronically commutated motor There are no brushes on the rotor and commutation is performed electronically at certain rotor positions The stator magnetic circuit is usually made from magnetic steel sheets Stator phase windings are inserted in the slots distributed winding as shown in Figure 3 1 or it can be wound as one coil on the magnetic pole Magnetization of the permanent magnets and their displacement on the rotor are chosen in such a way that the back EMF the voltage induced into the stator winding due to rotor movement shape is trapezoidal This allows a rectangular shaped 3 phase voltage system see Figure 3 2 to be used to create a rotational field with low torque ripples DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 23 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control STATOR STATOR WINDING IN SLOTS SHAFT ROTOR AIR GAP PERMANENT MAGNETS Figure 3 1 BLDC Motor Cross Section The motor can have more than just one pole pair per phase This defines the ratio between the electrical revolution and the mechanical revolution The BLDC motor shown has three pole pairs per phase which represent three electrical revolutions per one mechanical revolution VOLTAGE PHASE A PHASE B PHASE C ELECTRICAL ANGLE 2
72. age evaluation hardware and motor set are listed in Table 2 3 It is targeted first of all to software evaluation with small motors Table 2 3 Low Voltage Evaluation Hardware Set Specifications Hardware Boards Characteristics Input voltage 12 Vdc Maximum dc bus voltage 16 0 V Maximal output current 4 0A Motor Characteristics Motor type 4 poles three phase star connected BLDC motor Speed range 5000 rpm at 60 V Maximal line voltage 60 V Phase current 2A Drive Characteristics Output torque 0 140 Nm at 2 A Speed range 1400 rpm Input voltage 12 Vdc Maximum dc bus voltage 15 8 V Over current over voltage and Protection under voltage fault protection Load Characteristic Type Varying This hardware set is dedicated for medium power phase current lt 50 A and automotive voltage The specifications for a low voltage hardware and motor set are listed in Table 2 4 The hardware power stage board is dedicated for 12 V but can be simply configured to a 42 V supply described in documentation for the ECLOVACBLDC board The supplied motor is targeted for 12 V Designer Reference Manual MOTOROLA System Description For More Information On This Product Go to www freescale com 21 Freescale Semiconductor Inc System Description Table 2 4 Low Voltage Hardware Set Specifications Input voltage
73. al capacitance is very small Its influence is only significant during the PWM switching when the system experiences very high du dt The effect of mutual capacitance is described in section 3 2 4 4 Effect of Mutual Phase Capacitance Note that the configuration of the end turns of the phase windings has a significant impact Therefore it must be properly managed to preserve the balance of the mutual capacity This is especially important for prototype motors that are usually hand wound Failing to maintain balance of the mutual capacitance can easily disqualify such motors from using sensorless techniques based on the back EMF sensing Usually the BLDC motors with windings wound on separate poles show minor presence of the mutual capacitance Thus the disturbance is insignificant 6 2 4 2 Effect of Mutual Inductance NOTE CAUTION DRMO028 Rev 0 The negative effect on back EMF sensing of mutual inductance is not to such a degree as unbalanced mutual capacitance However it can be noticed on the sensed phase The difference of the mutual inductances between the coils which carry the phase current and the coil used for back EMF sensing causes the PWM pulses to be superimposed onto the detected back EMF voltage The effect of mutual inductance is described in section 3 2 4 3 Effect of Mutual Inductance The BLDC motor with stator windings distributed in the slots has technically higher mutual inductances than other types There
74. ale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control Section 1 Introduction 1 1 Contents 1 2 Application 13 1 3 Benefits of the 13 1 2 Application Functionality This Reference Design describes the design of a low cost sensorless 3 phase brushless dc BLDC motor control with back EMF electromotive force zero crossing sensing It is based on Motorola s MC68HC908MR32 microcontroller which is dedicated for motor control applications The system is designed as a motor drive system for medium power three phase BLDC motors and is targeted for applications in automotive industrial and appliance fields e g compressors air conditioning units pumps or simple industrial drives The reference design incorporates both hardware and software parts of the system including hardware schematics 1 3 Benefits of the Solution The design of very low cost variable speed BLDC motor control drives has become a prime focus point for the appliance designers and semiconductor suppliers Today more and more variable speed drives are put in appliance or automotive products to increase the whole system efficiency and the product performance Using of the control systems based on semiconductor components and MCUs is mandatory to satisfy requirements for high efficiency performance and cost of the system DRM028
75. alignment period ends Build the code see Software Execution Build You can also tune regulator dynamic characteristics of current transients steps 17 to 26 or finish the regulators tuning Run the code see Software Execution and Execute from Evaluation Board Start the PC master software tuning project Select Current Parameters Tuning subproject see Software Parameters Tuning with PC Master Software Project File in order to be able to modify the current regulator You can see the actual current and required alignment current on the Current Parameters Tuning New Scope or measure the powered motor coil current on real oscilloscope Set PC master software control mode and start motor see Application Control and PC Master Software Remote Operating Mode DRMO28 Rev 0 142 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor 22 Observe the current transient at Alignment start then stop motor or reset software 23 Then modify the regulator parameters with PC master software as in steps 8 9 10 and 11 24 Repeat steps 21 to 23 until regulation is improved 25 Open const cust x h and modify the regulator parameters with the final variable values evaluated with PC master software 26 Build the code see Software Execution and Build The last Alignment setting constant is Alignment Time per
76. an deliver peak currents up to 46 amps In combination with one of Motorola s embedded motion control series control boards it provides a software development platform that allows algorithms to be written and tested without the need to design and build a power stage It supports a wide variety of algorithms for controlling BLDC motors and PM Synchronous motors Input connections are made via 40 pin ribbon cable connector J13 Power connections to the motor are made with fast on connectors J16 J17 and J18 They are located along the back edge of the board and are labeled Phase A Phase B and Phase C Power requirements are met with a 12 volt power supply that has a 10 to 16 volt tolerance Fast on connectors J19 and J20 are used for the power supply J19 is labeled 12V and is located on the back edge of the board J20 is labeled OV and is located along the front edge Current measuring circuitry is set up for 50 amps full scale Both bus and phase leg currents are measured A cycle by cycle overcurrent trip point is set at 46 amps DRMO28 Rev 0 Hardware Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design Low Voltage Hardware Set Components The LV BLDC power stage has both a printed circuit board and a power substrate The printed circuit board contains MOSFET gate drive circuits analog signal conditioning low voltage power supplies and some of t
77. anual Sensorless BLDC Motor Control Table 4 5 5 1 6 1 6 2 6 3 DRM028 Rev 0 List of Tables Title Page Software Specifications 18 High Voltage Hardware Set Specifications 20 Low Voltage Evaluation Hardware Set Specifications 21 Low Voltage Hardware Set Specifications 22 PC Master Software Communication Commands 51 PC Master Software API 52 Electrical Characteristics of Control Board 66 Electrical Characteristics of Power Stage 68 Electrical Characteristics 69 Electrical Characteristics of the EVM Motor Board 71 Characteristics of the BLDC 71 Electrical Chatacteristics of the 3 Ph BLDC Low Voltage Power Stage 74 solware Variables 76 Required Software Configuration for Dedicated Hardware 118 Sit dub PRG daen EASRA Red aE EA Da 146 PWM Frequency 157 Designer Reference Manual MOTOROLA 11 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc List of Tables Designer Reference Manual DRM028 Rev 0 12 MOTOROLA For More Information On This Product Go to www freescale com Freesc
78. ation On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Phase Magnetic Flux Linkage Phase Back EMF Cbot Abot Bhots _ NATURAL COMMUTATION POINT s 4 ACTING POWER SWITCH IN THE POWER STAGE Phase Phase Back EMF Figure 3 3 BLDC Motor Back EMF and Magnetic Flux Designer Reference Manual The filled areas in the tops of the phase back EMF voltage waveforms indicate the intervals where the particular phase power stage commutations occur The power switches are cyclically commutated through the six steps therefore this technique is sometimes called six step commutation control The crossing points of the phase back EMF voltages represent the natural commutation points In normal operation the commutation is performed here Some control techniques advance the commutation by a defined angle in order to control the drive above the pulse width modulator PWM voltage control DRMO28 Rev 0 26 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Brushless DC Motor Control Theory 3 2 2 3 Phase BLDC Power Stage The voltage for 3 phase BLDC motor is provided by a 3 phase power stage controlled by digital signals Its topology is the one as for the AC induction motor refer to Fig
79. ation are delivered together in the bldc_zerocrosO8MR32 directory It consists of files listed in Application HC08 Software Files 6 4 2 1 Application HC08 Software Files The application HCO8 software files are e Mlidc zerocros08MR32Wbldc zerocross mocp application project file bIdc_zerocrosO8MR32 sources const_cust_hv h definitions for software customizing for high voltage 230 115 Vac power board e zerocros08MR32 sources const cust evm h definitions for software customizing for EVM motor board 12 V low power bldc_zerocrosO8MR32 sources const_cust_lv h definitions for software customizing for low voltage 12 Vdc power board NOTE Change the code fun c file to include include one of const cust hv h const cust evmm h or const cust lv h files according to the hardware platform used See Table 6 1 Table 6 1 Required Software Configuration for Dedicated Hardware Platform Hardware Dedicated Required Software Platform Customizing File Configuration include const cust hv h into code fun c High voltage hardware const cust hv h done with default software setting Designer Reference Manual DRMO28 Rev 0 118 User Guide MOTOROLA For More Information On This Product Go to www freescale com 28 Rev 0 Freescale Semiconductor Inc User Guide Application Hardware and Software Configuration Table 6 1 Required Software Configuration for Dedicate
80. ax cA Curr Range Max cA S16 lt 32768 32767 gt Current range maximum A 10 2 Designer Reference Manual DRMO28 Rev 0 52 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Application Control Type S8 signed 8 bit U8 unsigned 8 bit S16 signed 16bit U16 unsigned 16bit The system registers Sys3 Motor_Ctrl Motor_Status Failure flags are described by definitions of Sys3 Def Motor Ctrl Def Motor Status Def Failure Def typedef union struct unsigned int HV 1 BITO High Voltage board Flag unsigned int LV 1 BIT1 Low Voltage board unsigned int EVMm 1 BIT2 EVMm board unsigned int BIT3 do BIT3 RESERVED unsigned int PCMode 1 BIT4 PCMaster manual mode Flag unsigned int BIT5 1 BITS RESERVED unsigned int BIT6 1 BIT6 RESERVED unsigned int Alignment 1 BIT7 Alignment state Proceeding B Alignment PCMode EVMm LV HV char R Sys3 Def System register 3 Definition typedef union struct unsigned int StartCtrl 1 Switch Start set to START Flag unsigned int BIT1 1 BIT1 RESERVED unsigned int BIT2 1 BIT2 RESERVED unsigned int BIT3 1 BIT5 RESERVED unsigned int BIT4 1 BIT4 RESERVED unsigned int BIT5 1 BIT6 RESERVED unsi
81. ble connector Motor feedback signals can be connected to Hall sensor encoder connector Power is supplied Designer Reference Manual DRMO28 Rev 0 64 Hardware Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design All HW Sets Components through the 40 pin ribbon cable from the optoisolation board or low voltage power stage The control board is designed to run in two configurations It can be connected to an M68EM08MR32 emulator via an M68CBLO8A impedance matched ribbon cable or it can operate using the daughter board The M68EMO8MR32 emulator board may be used in either an MMDS05 08 or MMEVS05 08 emulation system Figure 4 4 shows a block diagram of the board s circuitry FORWARD REVERSE SPEED SWITCH TACHOMETER Ld START STOP INPUT VF SWITCH EFFECT INPUTS 3 RESET EMULATOR Se naa PROCESSOR a CONNECTOR 8 2 OPTION SWITCHES REGULATED de POWER POWER SUPPLY PWM LEDs 6 12 Vdc OPTO POWER DRIVER I O CONNECTOR E Fi N 40 PIN RIBBON OVERCURRENT P RSENFITENP BACK EMF CONNECTOR OVERVOLTAGE SENSE INPUTS INPUTS INPUTS PWM 6 MISC POWER AND OUTPUTS CONTROL I O Figure 4 4 MC68HC908MR32 Control Board 4 3 1 1 Electrical Characteristics of the MC68HC908MR32 Control Boar
82. com Freescale Semiconductor Inc 6 5 Tuning for Customer Motor This section describes how to modify the software parameters for any BLDC motor and some hardware adaptations The software parameters can be evaluated from a PC computer using PC master software so the first subsection describes tuning the PC master software project file A follow up for software customizing to a customer motor is shown in Figure 6 7 Before starting the software modification for a customer motor and application it is recommended that you check the application and motor suitability This is explained in the section 6 2 Application Suitability Guide The Parameters File Selection must be made according to Hardware Configuration used If a modified hardware power stage is used the appropriate constants in const_cust_x h file must be set as described in the section 6 5 3 1 Software Customizing to Power Stage If a low voltage board with a modification for 42 V is used the constants VOLT_HW_MAX and VOLT_MAX_FAULT_V must be changed If one of the three standard power stages is used the software customizing to power stage is not needed For software customizing to customer motor and application a setting must be made as explained in 6 5 4 Software Customizing to Motor Voltage and Current Settings 6 5 4 3 Alignment Current and Current Regulator Setting 6 5 5 Software Customizing to Motor Commutation and Start up Control Se
83. commended for software evaluation 2 Programmed MCU MC68HC908MR32 Where a daughter board module with MC68HC908MR32 processor is plugged into the controller board ECCTRMR32 instead of the emulator cable the processor must be programmed in an external programmer This solution is recommended for final tests Figure 4 1 Figure 4 2 and Figure 4 3 show the configuration with MMDS evaluation board The sections 4 3 All HW Sets Components 4 4 High Voltage Hardware Set Components 4 5 Low Voltage Evaluation Motor Hardware Set Components and 4 6 Low Voltage Hardware Set Components will describe the individual boards Designer Reference Manual DRMO28 Rev 0 58 Hardware Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design System Configuration and Documentation 4 2 1 High Voltage Hardware Set Configuration The system configuration for a high voltage hardware set is shown in Figure 4 1 12VDC PC Computer RS232 GND PC Master 40w flat ribbon cable 40w flat ribbon cable 3ph AC BLDC High Voltage Power Stage Controller Board HC908MR32 ECCTR908MR32 Optoisolation Board ECOPT 100 240VAC 49 61 Hz ECOPTHIVACBLDC KITMMDS08MR32 ECMTRHIVBLDC PC Computer Not Connected Not Connected RS232 emulator Figure 4 1 High Voltage Hardware System Configu
84. commutation stage This zero crossing detection signal is transferred to the timer input pin The comparator control and zero crossing signals plus the voltage waveforms are shown in Figure 3 13 DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 37 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Phase Selection Tek 10 0 5 2 Acqs MUX Command is ins T piene evan a H 2 da Phase Comparator Output TU Zero crossing edge 34 unen zc a Branch Voltage RET WV Ps i TUI II i Back EMF zero crossing detection 1 500mV Ch2 5007 5 00 Ch2 f 2 6 V Ch3 5 00 V 810 500 Reference Level Commutation Signal 90 Zero Crossing Signal Figure 3 13 The Zero Crossing Detection 3 3 Used Control Technique 3 3 1 Sensorless Commutation Control This section concentrates on sensorless BLDC motor commutation with back EMF zero crossing technique In order to start and run the BLDC motor the control algorithm has to go through the following states Alignment e Starting Back EMF Acquisition Running Figure 3 14 shows the transitions between the states First the rotor is aligned to a known position then the rotation is started without the position feedback When the rotor moves back EMF is acquired so the Designer Refe
85. d The electrical characteristics in Table 4 1 apply to operation at 25 C DRM028 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 65 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design Table 4 1 Electrical Characteristics of Control Board Characteristic Symbol Min Typ Max Units dc power supply voltage Vdc 10 8 12 16 5 V Quiescent current lec 80 mA Min logic 1 input voltage V EM MR32 IH RM y Max logic 0 input voltage V __ 2 MR32 IL Sie Propagation delay t _ Hall sensor encoder input 209 iy Analog input range Vin 0 5 0 V RS 232 connection speed 9600 Baud PWM sink current lpk 20 mA 1 When operated and powered separately from other Embedded Motion Control tool set products 4 4 High Voltage Hardware Set Components 4 4 1 3 Phase AC BLDC High Voltage Power Stage Motorola s embedded motion control series high voltage HV ac power stage is a 180 watt one fourth horsepower 3 phase power stage that will operate off of dc input voltages from 140 to 230 volts and ac line voltages from 100 to 240 volts In combination with one of the embedded motion control series control boards and an optoisolation board it provides a software development platform that allows algorithms to be written and tested without the need to design and build a power
86. d Hardware Platform Hardware Dedicated Required Software Platform Customizing File Configuration Low voltage evaluation const_cust_evmm include const_cust_evmm h motor hardware h into code fun c Low voltage hardware const cust lv h into code fun c e bidc_zerocrosO8MR32 sources code_fun c program C language functions e bIdc_zerocrosO8MR32 sources code_fun h program C language functions header e bIdc_zerocrosO8MR32 sources const h main program definitions bldc_zerocrosO8MR32 sources mr32io h MC68HC908MR32 registers definitions file bldc_zerocrosO8MR32 sources mr32_bit h MCHC908MR32 register bits definitions file e bIdc_zerocrosO8MR32 sources bldc08 c main program e _ bldc_zerocrosO8MR32 sources code_start c motor alignment and starting back EMF acquisition state functions e bldc_zerocrosO8MR32 sources code_start h motor alignment and starting back EMF acquisition state function header e Abldc zerocros08MR32 sourcesWcode run c motor running state function e bIdc_zerocrosO8MR32 sources code_run h motor running state function header e zerocros08MR32Nsources code isr c program interrupt functions e zerocros08MR32sources code isr h program interrupt functions header Designer Reference Manual MOTOROLA User Guide 119 For More Information On This Product Go to www freescale com F
87. d for operating the test setup minimizes the possibility of electrical shock e Operation in lab setups that have grounded tables and or chairs should be avoided e Wearing safety glasses avoiding ties and jewelry using shields and operation by personnel trained in high voltage lab techniques are also advisable e Power transistors the PFC coil and the motor can reach temperatures hot enough to cause burns When powering down due to storage in the bus capacitors dangerous voltages are present until the power on LED is off DRMO28 Rev 0 112 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Application Hardware and Software Configuration 6 4 Application Hardware and Software Configuration 6 4 1 Hardware Configuration NOTE DRMO028 Rev 0 As mentioned the software can be configured to run on one of the three hardware and motor platforms High Voltage Hardware Set Configuration e Low Voltage Evaluation Motor Hardware Set Configuration e Low Voltage Hardware Set Configuration The hardware setups are shown in Figure 6 1 Figure 6 2 and Figure 6 3 These setups are described in following subsections see Hardware and Drive Specifications for each platform characteristics The supplied controller boards for MC68HC908MR32 ECCTRMR32 allows two possibilities for software execution 1 MMDS Evaluation Board KITMMDSMR
88. e Edit View Explorer Item Project Help SOE Hale Ha gl eaea i 22 3ph BLDC motor on HCO8MR24 ri Designed By Motorola Czech System Laboratories Roznov p Radh Czech Republi MOTOROLA 3ph BLDC motor on HC908MR32 PC Master Mode Start Stop Motor Motor Stopped nac 492 rpm 2 500 rp DC bus current 69 mA comm period 6172 us Temperature 1315 Real Failures speed No Failures click here comm period uS 500 rpm to display Identified hardware Power stage board Not recognized control page Optoisolation board Not recognized CPU HC908MR32 z controfpage 1 Period Ready Designer Reference Manu TBoardldent 0 1 Dae Tdant nyff Ib COMM speed 9600 bps Figure 6 6 PC Master Software Control Window The following control actions are supported e Setting PC master software manual control mode PC Master Mode Radio button al DRMO28 Rev 0 124 User Guide For More Information On This Product Go to www freescale com MOTOROLA 28 Rev 0 Freescale Semiconductor Inc User Guide Application Hardware and Software Configuration Application control from PC master software requires that PC master software control mode must be set Before changing PC master software manual control mode by PC Master Mode Radio button the controller board START STOP switch must be set to STOP This is a
89. e in order to synchronize zero crossing capture with the middle of central aligned PWM This technique rejects the noise caused by PWM from the back EMF signal When this ISR is initiated then three samples of the zero crossing input BEMF_IN are taken and the state is evaluated Based on the expected edge V_TASC2 ELS2A_ELS2B and the evaluated state of the BEMF_IN pin the zero crossing event is verified If it is accepted then the captured time is stored in variable T_ZCros and the PWM ISR is finished The appropriate flag captured received the zero crossing event ICR_F is set Current Measurement Interrupt Service Routine Designer Reference Manual DRM028 Rev 0 98 Software Design MOTOROLA For More Information On This Product Go to www freescale com 5 5 6 Running State DRM028 Rev 0 Freescale Semiconductor Inc Software Design State Diagram The output compare function is used to synchronize initiating the dc bus current sampling with the PWM cycle and also for the commutation timing Error Handler If the BLDC motor is controlled properly commutation events must be locked to the back EMF zero crossing feedback When that feedback is lost commutation time is derived from previous commutation events If feedback does not recover during a defined number of commutations constant C_MaxErr then the situation is evaluated as irrecoverable commutation error and the fault state is entered Measu
90. eak in the sequential execution of a program to respond to signals from peripheral devices by executing a subroutine input output I O Input output interfaces between a computer system and the external world A CPU reads an input to sense the level of an external signal and writes to an output to change the level on an external signal KITMMDSO8MR32 MMDS 68HC908MR32 16 developement kit logic 1 A voltage level approximately equal to the input power voltage logic 0 A voltage level approximately equal the ground voltage Vss 68 8 A Motorola family of 8 bit MCUs MC Motor Control MCU Microcontroller Unit A complete computer system including a CPU memory a clock oscillator and input output I O on a single integrated circuit MW Metrowerks Corporation Designer Reference Manual DRM028 Rev 0 164 Glossary MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Glossary PCM PC master software for communication between PC computer and system phase locked loop PLL A clock generator circuit in which a voltage controlled oscillator produces an oscillation which is synchronized to a reference signal PMP PC master software project file PVAL PWM value register of motor control PWM module of MC68HC908MR32 microcontroller It defines the duty cycle of generated PWM signal PWM Pulse Width Modu
91. eared when the software evaluates the start condition When Stop F is cleared the software checks the over voltage condition and the application starts The system Alignment and Starting Back EMF Acquisition states are provided by Alignment and Start functions in the code start c file both are called from main The functionality during the start and running state is described in 3 3 1 Sensorless Commutation Control During the starting back EMF acquisition state the commutation time Designer Reference Manual DRMO28 Rev 0 84 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Main Software Flowchart preset calculations are prepared in the StrtCmtPreset function and commutation time set calculations are provided by the StrtCmtSet function DRM028 Rev 0 Designer Reference Manual MOTOROLA Software Design 85 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc YES FAULT STATE STOP MOTOR WAIT UNTIL FAULT CLEAR y APPLICATION INITIALIZATION CURRENT OFFSET CALIBRATION SYSTEM REGISTERS INITIALIZATION PWM INITIALIZATION TIMER 1 CURRENT SENSING TO PWM SYNCHRONIZATION ADC MEASUREMENT INIT Software Design STAND BY CHECK START STOP SWITCH IF PC MASTER S W MODE CHECK STARTC
92. ement and virtual timer 3 service where timer 1 is providing the timer 3 time base When over current is discovered the OVC_F flag is set Finally the ADC is set according to the Nxt Chnl variable to prepare speed potentiometer or temperature sensing This interrupt is provided by the TIMACh1 Int function Interrupt Timer 2 sets commutation actions If commutation is enabled CmtE_F flag is set the following actions are done e PWM commutation step e Synchronization of timer 1 for current measurement with PWM Designer Reference Manual MOTOROLA Software Design 87 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design e Phase commutated flag PC_F is set e Actual time from timer counter register commutation time is recorded in T Cmt This interrupt is provided by the TIMACh3_Int function Interrupt PWM Reload provides back EMF zero crossing sensing The zero crossing input is sampled 2 or 3 times The back EMF state value is compared with expecting rising falling edge If the value corresponds with expecting edge the zero crossing get flag ICR F is set and the actual time from timer counter register zero crossing time is recorded in T ZCros This interrupt is provided by PWMMC_Int function in code isr c Designer Reference Manual DRMO28 Rev 0 88 Software Design MOTOROLA For More Information On This Product Go to www freescale co
93. er ZCrosFIt U16 UNIT PERIOD T2 US Zero crossing period filtered T2 vd x UNIT PERIOD T2 US Timer 2 variable T ZCros U16 UNIT PERIOD T2 US Zero crossing time n T ZCrosO UNIT PERIOD T2 US Zero crossing time n 1 T Cmt U16 UNIT PERIOD T2 US Commutation time Curr Range Max cA Curr S8 Curr Range Max cA dc bus current Curr Range Max cA Curr Align S8 Curr Range Max cA Required current during alignment state PIParamsScl S8 Currr Structure Current PI regulator parameters VOLT RANGE MAX Volt U8 VOLT RANGE MAX dc bus voltage V TASC2 U8 Back EMF zero crossing expecting edge V MUX Preset value of back EMF zero crossing phase multiplexer Designer Reference Manual DRMO28 Rev 0 76 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Data Flow Type S8 signed 8 bit U8 unsigned 8 bit S16 signed 16bit U16 unsigned 16bit union 16 bits access or 2 8bit access The system registers Sys1 flags are described by definitions of Sys3_Def typedef union struct unsigned int PC 1 BITO Phase Commutation Flag unsigned int Off F 1 BIT1 Offset timeout flag Offset timeout can be measured unsigned int ICR F 1 BIT2 Input Capture was succesfuly Received Flag unsigned int Rmp F 1 BIT3 Speed Ramp Flag motor ramping unsigned
94. es on both 230 Vac and 115 Vac mains Table 2 2 High Voltage Hardware Set Specifications Hardware Boards Characteristics Input voltage 230 Vac or 115 Vac Maximum dc bus voltage 407 V Maximal output current 2 93A Motor Brake Set Manufactured EM Brno Czech Republic EM Brno SM40V Motor type 3 phase star connected BLDC motor Pole Number 6 Motor Characteristics Speed range 2500 rpm at 310 V Maximum electrical power nem Phase voltage 3 220 V Phase current 0 55 A 0 9 RE BLDC Motor Nominal Voltage 3x 27 V Brake Characteristics Nominal Current 2 6 Pole Number 6 Nominal Speed 1500 rpm lt 2500 rpm Drive Characteristics Speed range determined by motor used Maximum dc bus voltage 380 V Optoisolation Required Over current over voltage and under voltage fault protection Load Characteristic Type Varying DRMO28 Rev 0 20 System Description For More Information On This Product Go to www freescale com MOTOROLA Freescale Semiconductor Inc 2 3 2 2 Low Voltage Evaluation Hardware Set Specification 2 3 2 3 Low Voltage Hardware Set Specification DRM028 Rev 0 System Description System Specification This hardware set is dedicated for 12 V voltage and very low power phase current lt 4 A The specifications for a low volt
95. eters with PC master software as in steps 11 to 14 26 Change SPEED MIN RPM if problems occur at low speed 27 Repeat steps 21 to 25 until regulation is improved 28 Open const cust x h and modify the regulator parameters with the final variable values evaluated with PC master software 29 Build the code see Software Execution and Build Most important software settings are described in previous sections but for some applications PWM frequency must be modified It is described in PWM Frequency and Current Sampling Period Setting Once you set the speed control and the motor is running in all start speed up and slow down conditions the software parameters are set for the motor Remember that all parameters are set in const cust x h Then it is possible to program the FLASH memory of the MC68HC908MR32 device 6 5 7 PWM Frequency and Current Sampling Period Setting PWM frequency and current sampling period settings are not usually needed The PWM frequency also affects the current sampling period Consequently the current regulation setting should be done while understanding their mutual dependency Therefore the PWM frequency setting is provided in the file const h instead of const cust x h 6 5 7 1 PWM Frequency For the PWM frequency setting follow the label CAN CHANGE FPWM n in const h file The PWM frequency setting is provided by CAN CHANGE FPWM 1 define SET PER 32 0 Designer Reference Manual
96. ff The state diagram for this state is shown in Figure 5 12 MOTOR STOP IS REQUIRED STOP_F 1 TIMER1 TIM A CH1 INTERRUPT MOTOR IS STOPPED CURRENT MEASUREMENT PWM IS OFF DONE CURRENT MEASUREMENT F 1 ISR E c c Figure 5 12 STOP State 5 5 8 Fault State If over voltage over current or commutation fault occurs the motor control PWM s are disabled and control enters the fault state where it remains until RESET or clear failure start switch set OFF or PCMode amp ClearFail The fault state is indicated by the Red LED diode blinking Clear Failure Test Designer Reference Manual DRMO28 Rev 0 102 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Implementation Notes The failure Failure 0 is tested In manual mode PCMode 0 the switch in the stop position clears the failure In PC master software mode PCMode 1 the failure is cleared by ClearFail flag or the switch in the stop position If start condition is valid Strt_F is set Stop_F is cleared and the next state entered See Figure 5 13 TIMER1 TIM A CH1 INTERRUPT MOTOR IS STOPPED PWM IS OFF CURRENT MEASUREMENT IS DONE WAIT FOR DONE CURRENT MEASUREMENT CMD_F 1 CLEAR FAILURE va CLEAR FAILURE TEST ERROR INDICATION RED LED IS BLINKING C CLEAR FAILURE START SWITCH SET OFF
97. fore this effect is more significant On the other hand the BLDC motor with windings wound on separate poles shows minor presence of the effect of mutual inductance However noticeable this effect it does not degrade the back EMF zero crossing detection because it is cancelled at the zero crossing point Additional simple filtering helps to reduce ripples further Designer Reference Manual MOTOROLA User Guide 111 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 6 3 Warning Designer Reference Manual This application operates in an environment that includes dangerous voltages and rotating machinery Be aware that the application power stage and optoisolation board are not electrically isolated from the mains voltage they are live with risk of electric shock when touched An isolation transformer should be used when operating off an ac power line If an isolation transformer is not used power stage grounds and oscilloscope grounds are at different potentials unless the oscilloscope is floating Note that probe grounds and therefore the case of a floated oscilloscope are subjected to dangerous voltages The user should be aware that e Before moving scope probes making connections etc it is generally advisable to power down the high voltage supply To avoid inadvertently touching live parts use plastic covers e When high voltage is applied using only one han
98. g Let us assume a usual situation where the BLDC motor is driven in six step commutation mode using PWM technique where both top and bottom switches in the diagonal are controlled using the same signal so called hard switching PWM technique The motor phases A and B are powered and phase C is free having no current So the phase C can be used to sense the back EMF voltage This is described by the following conditions Sap Sge PWM 1 _ 4l Uva 506 5 ig ig i dig dig di ise 0 di e 0 EQ 3 2 UbackEMF a UbackEMF b UbackEMF c 0 The branch voltage uy can be calculated using the above conditions 1 Usc 3 gt UbackEMF x Lac Lo EQ 3 3 DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 29 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control After evaluation the expression of the branch voltage uy is as follows 3 1 di 5 e 5 Lac a Ls EQ 3 4 The same expressions can also be found for phase A and B 3 1 di 5 5 Loa Lo EQ 3 5 5 UpackEME b Le EQ 3 6 The first member in the equation EQ 3 6 demonstrates the possibility to indirectly sense the back EMF between the free not powered phase terminal and the zero point defined at half of the dc bus voltage see Figure
99. ge 12 V and very low power phase current lt 4 A 3 Low Voltage Hardware Set For automotive voltage 12 V or possibly 42 V and medium power phase current lt 50 A DRM028 Rev 0 Designer Reference Manual MOTOROLA System Description 17 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc System Description 2 3 1 Software Specification The application software is practically the same for all three hardware platforms The only modification needed is to include one of three constants that customize the hardware and motor parameter settings The software written in C language specifications are listed in Table 2 1 A useful feature of the software is serial communication with PC master software protocol via RS232 The PC master software is PC computer software which allows reading and setting of all the system variables and can also run html script pages to control the application from the PC Another feature of the BLDC control software is on line parameter modification with PC master software which can be used for software parameter tuning to a customer motor Table 2 1 Software Specifications 3 phase trapezoidal BLDC motor control star or delta connected Sensorless with back EMF zero crossing commutation Control Algorithm control Speed closed loop control Motoring mode Target Processor MC68HC908MR32 Language C language wit
100. gned int BIT6 1 BIT6 RESERVED unsigned int ClearFail 1 BIT7 Clear failure Status poB ClearFail StartCtrl char R Motor Ctrl Def PC master software Motor Control Flags Definition typedef union struct DRM028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 53 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control unsigned int Switch Start 1 BITO Switch START STOP set to START Flag unsigned int Running 1 BIT1 Motor is running Alignment Start or Running state unsigned int BIT2 1 BIT2 RESERVED unsigned int V120 1 BIT3 120 V DC Bus detected only for HV DC Bus unsigned int BIT4 1 BIT4 RESERVED unsigned int BIT5 1 BIT5 RESERVED unsigned int BIT6 1 BIT6 RESERVED unsigned int BIT7 1 BIT7 RESERVED B x x v120 Running Switch Start char R Motor Status Def PC master software Motor Status Flags register Definition typedef union struct unsigned int OverCurrent 1 BITO Over Current Failure unsigned int OverHeating 1 BIT1 Over Heating unsigned int VoltageFailure 1 BIT2 Over Voltage unsigned int BIT3 2 BIT5 RESERVED unsigned int BIT4 he BIT4 RESERVED unsigned int BIT5 zd BIT6 RESERVED
101. h some arithmetical functions in assembler Compiler Metrowerks ANSI C cC Compiler for 8 Manual interface start stop switch speed potentiometer Application control LED indication Control PC master software remote interface via RS232 using PC computer MCU Oscillator Frequency 4 MHz with default software setting MCU Bus Frequency 8 MHz with default software setting Minimal BLDC Motor Commutation Period Without PC Master Software Communication 333 us with default software setting and COEF_HLFCMT 0 450 Designer Reference Manual DRMO28 Rev 0 System Description MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc System Description System Specification Table 2 1 Software Specifications Minimal BLDC Motor Commutation 520 us with default software setting and COEF_HLFCMT Period with PC 0 450 Master Software Control Software is prepared to run on three optional board and motor hardware sets High voltage hardware set at variable line voltage 115 230 Vac Targeted TE Hardware software customizing file const_cust_hv h Low voltage evaluation motor hardware set software customizing file const_cust_evmm h Low voltage hardware set software customizing file const_cust_lv h Configuration to one of the three required hardware sets is provided by inclusion of dedicated s
102. he large passive power components This board also has a 68HC705JJ7 microcontroller used for board configuration and identification All of the power electronics that need to dissipate heat are mounted on the power substrate This substrate includes the power MOSFETs brake resistors current sensing resistors bus capacitors and temperature sensing diodes Figure 4 5 shows a block diagram POWER INPUT BIAS 3 POWER BRAKE MOSFET SIGNALS POWER MODULE TO FROM GATE CONTROL L DRIVERS nue SM him E PHASE CURRENT PHASE VOLTAGE d em BUS CURRENT BUS VOLTAGE MONITOR BOARD ID BLOCK ZERO CROSS BACK EMF SENSE Figure 4 6 Block Diagram 4 6 1 1 Electrical Characteristics of the 3 Ph BLDC Low Voltage Power Stage The electrical characteristics in Table 4 6 apply to operation at 25 C with a 12 Vdc supply voltage DRMO028 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 73 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design Table 4 6 Electrical Chatacteristics of the 3 Ph BLDC Low Voltage Power Stage Characteristic Symbol Min Typ Max Units Motor Supply Voltage Vac 10 12 16 V Quiescent current loc 175 mA Min logic 1 input voltage Vin 2 0 V Max logic 0 input
103. he period is timed by timer 3 with the constant PER_T3_RUN_US PWM duty cycle is set for all six PWM channels according to regulator output OutReg_U8 The maximum duty cycle is at OutReg_U8 255 The implementation is described in Implementation Notes 5 6 3 BLDC Speed Control and Calculation 5 3 9 Process Alignment Control The process alignment control controls the current Curr using the PI regulator during alignment state see 5 5 State Diagram The dc bus current is regulated to required value Curr_Align The current regulator parameters gain internal and input output variables are located in the structure PlParamsScl S8 Curr The current controller works with a constant execution sampling period The period is timed by timer1 with the constant PER CS T1 US 5 3 10 Processes Commutation and Zero Crossing Preset and Set Designer Reference Manual The processes commutation and zero crossing preset and set provides the BLDC commutation and zero crossing selection Here the BLDC commutation means generation of the six step commutation which creates the voltage system shown in Figure 3 2 The required BLDC motor voltage system and commutation is provided using the MC68HCO08MR32 PWM block The zero crossing selection means the selection of the required zero crossing phase as described in 3 2 4 2 Indirect Back EMF Sensing and DRMO28 Rev 0 82 Software Design MOTOROLA For More Information On This Product
104. iated here Over Current Detection The dc bus current is periodically sensed and the over current condition is evaluated After a defined number successive over current events CNTR_OVC the control flow enters into the fault state 5 5 5 Back EMF Acquisition State DRM028 Rev 0 The back EMF acquisition state provides the functionality described in 3 3 1 4 Starting Back EMF Acquisition and 3 3 1 5 Starting Commutation Time Calculation Figure 5 10 shows the state transitions for the state First Commutation After the align state time out expires voltage is applied to another phase pair The first commutation is made and the PWM duty cycle is constant This value has been defined by the current controller during the Aalign state The calculation of the commutation time is explained in 3 3 1 5 Starting Commutation Time Calculation Designer Reference Manual MOTOROLA Software Design 95 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Second Commutation The commutation time T2 is calculated from the previous commutation time and the start commutation period Per_CmtStart This time is set to timer 2 Then the new PWM multiplexer logic data is readied for when the commutation interrupt performs the next commutation The calculation of the commutation time is explained in 3 3 1 5 Starting Commutation Time Calculation Measuremen
105. ing Back EMF Acquisition DRMO028 Rev 0 The back EMF sensing technique enables a sensorless detection of the rotor position however the drive must be first started without this feedback This is due to the fact that the amplitude of the induced voltage is proportional to the motor speed Hence the back EMF cannot be sensed at a very low speed and a special start up algorithm must be performed In order to start the BLDC motor the adequate torque must be generated The motor torque is proportional to the multiplication of the stator magnetic flux the rotor magnetic flux and the sine of the angle between these magnetic fluxes It implies for BLDC motors the following 1 The level of phase current must be high enough 2 The angle between the stator and rotor magnetic fields must be 90 30 The first condition is satisfied during the alignment state by maintaining dc bus current at a level sufficient to start the motor In the starting back EMF acquisition state the same value of PWM duty cycle is used as the one which has stabilized the dc bus current during the align state The second condition is more difficult to fulfill without any position feedback information After the alignment state the stator and the rotor magnetic fields are aligned 0 angle Therefore two fast commutations faster than the rotor can follow must be applied to create an angular difference in the magnetic fields see Figure 3 18 The
106. int Stop F 1 BIT4 Motor is going or is stopped unsigned int Strt 1 BIT5 Start Phase Flag unsigned int Run F 1 BIT6 Motor Running with back EMF feedback Flag unsigned int FOK F 1 BIT7 Feedback within the righ time Flag B FOK F Run F Strt F Stop F Rmp F ICR F Off F PC F char R Sysi Def System register 1 Definition Main data flow is displayed in Figure 5 1 The processes are described in the following subsections 5 3 2 Process Measurement The process provides measurement of analog values using ADC The measured inputs are dc bus current dc bus voltage and speed input The measurement is provided by the measurement handler The state diagram is explained in State Diagram 5 3 3 Start Stop Switch Reading and Start Stop Decision The process reads the start stop switch and provides start condition and clear failure decisions as explained in Stand By and Fault State DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 77 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design PC MASTER SOFTWARE PC Mode Start Ctrl Switch_Start Running A D CONVERTERS TIMER 1 PROCESS SPEED INPUT DC BUS VOLTAGE AND DC BUS CURRENT MEASUREMENT START STOP SWITCH START STOP SWITCH READING AND START STOP DECISION Sp_Input VOLTAGE CURRENT PROCESS ALIGNMENT STARTING RUN
107. iod ms MUST CHANGE 6 EXPER define PER T ALIGN MS 1000 0 Range 0 PER BASE ALIGN 05 1000 255 gt This period can be set experimentally This constant can also be evaluated using PC master software tuning file This period must be high enough to let the rotor stabilize during Alignment state It is recommended that you begin with large values such as 20 000 ms then it can be lowered The period should be set to ensure that the rotor and therefore also the current is stabilized at the end of Alignment state 6 5 5 Software Customizing to Motor Commutation and Start up Control Setting NOTE DRMO028 Rev 0 When all voltage and current settings are done the motor commutation and start up parameters need to be set For settings which must be done follow the labels MUST CHANGE nn MUST CHANGE EXPER file const cust x h For changes which can be done but usually are not necessary follow the labels CAN CHANGE nn CAN CHANGE EXPER file const cust x h Thanks to the Motorola patented start up technique the start parameters setting is quite simple and reliable However in order to reliably start the motor the commutation control constants must be properly set Detailed description starts here Designer Reference Manual MOTOROLA User Guide 143 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 6 5 5 1 Commutation Parameters
108. ion starts here An example of software customizing to power stage is shown in Example of Software Customizing to Hardware 6 5 3 2 Maximal PWM Duty Cycle Designer Reference Manual Maximal PWM duty cycle DRMO28 Rev 0 134 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor MUST IF HW CHANGE 1 define DUTY PWM MAX 0 96 Range 0 1 Proportional value of maximal PWM duty cycle is determined by power stage boards used DUTY PWM MAX must be set for any hardware customizing Some hardware boards need maximal duty cycle 1 in order to charge high side drivers for power inverters 6 5 3 3 Voltage Setting Hardware Customizing Maximal measurable voltage determined by hardware voltage sensing V MUST IF HW CHANGE 2 define VOLT_HW MAX 407 0 Range lt 0 infinity VOLT_HW_MAX must be changed when voltage sensing range is different from default hardware Maximum limit of dc bus voltage allowable for the hardware V MUST IF HW CHANGE 3 define VOLT MAX FAULT V 380 0 Range 0 VOLT RANGE MAX VOLT MAX FAULT V determines the maximal voltage when the drive fault state should be entered So the constant VOLT MAX FAULT V must be set according to maximal voltage limit of the power stage or the motor using the lower value Therefore setting this constant is also mentioned in Maximal and
109. is rectified and amplified 0 3 3 V with 1 65 V offset The internal MCU analog to digital A D converter and zero crossing detection are synchronized with the PWM signal This synchronization avoids spikes when the IGBTs or MOSFETs are switched and simplifies the electric circuit DRM028 Rev 0 Designer Reference Manual MOTOROLA System Description 15 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc System Description Power line DC Bus Voltage Current Temperature PC Master Required Speed Required Alignment Current DC Bus Current amp DC Bus Voltage Sensing 3 BEMF Voltage Zero Crossing Comparators Zero MUX Crossing Command signal Digital Outputs PWM Generator with Dead Time Crossing Zero Crossing Time moment Zero Crossing Period Position Recognition Commutation Control Commutation Period Actual Speed Speed PI Regulator Actual Current I jCurrent I Regulator for Alignment Figure 2 1System Concept HC08MR32 During the rotor alignment state the dc bus current is controlled by the current PI regulator In the other states motor running the phase voltage PWM duty cycle is controlled by the speed PI regulator Designer Reference Manual DRM028 Rev 0 16 System Description For More Information On This Product Go to www freescale com MO
110. is set Stop F is cleared and the next state entered Designer Reference Manual DRMO28 Rev 0 92 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design State Diagram CURRENT MEASUREMENT AND CURRENT CALIBRATION WHEN PWM IS OFF CURRENT IS HIGHER THAN LIMIT ERROR IN HARDWARE START CONDITION TEST START CONDITION START SWITCH CHANGED FROM STOP TO START OR START AND PC MODE AND START CTRL OVER VOLTAGE OR UNDER VOLTAGE SPEED INPUT AND DC BUS VOLTAGE MEASUREMENTS DONE Figure 5 8 Stand by State Speed input and dc bus voltage measurements The dc bus voltage is measured after the start switch is turned ON This prevents the measurement being disturbed by the power turn ON Where that dc bus voltage is not within the limits the control flow enters into the fault state DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 93 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design 5 5 4 Align State In the align state the rotor position is stabilized by applying PWM signals to only two motor phases no commutation When preset time out expires then this state is finished See Figure 5 9 RUN CONDITION STOP_F 0 CURRENT MEASUREMENT IS DONE CURRENT CONTROLLER ALIGN TIME OUT rena b _ 0 OVER CURR
111. lation reset To force a device to a known condition SCI See serial communication interface module SCI serial communications interface module SCI A module that supports asynchronous communication serial peripheral interface module SPI A module that supports synchronous communication software Instructions and data that control the operation of a microcontroller software interrupt SWI An instruction that causes an interrupt and its associated vector fetch SPI See serial peripheral interface module SPI SR switched reluctance motor timer A module used to relate events in a system to a point in time DRMO028 Rev 0 Designer Reference Manual MOTOROLA Glossary 165 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual DRMO28 Rev 0 166 Glossary MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc For More Information On This Product Go to www freescale com Freescale Semiconductor Inc HOW TO REACH US USA EUROPE LOCATIONS NOT LISTED Motorola Literature Distribution P O Box 5405 Denver Colorado 80217 1 303 675 2140 or 1 800 441 2447 JAPAN Motorola Japan Ltd SPS Technical Information Center 3 20 1 Minami Azabu Minato ku Tokyo 106 8573 Japan 81 3 3440 3569 ASIA PACIFIC Motorola Semiconductors H K Ltd Silico
112. les The actual speed of the motor can be calculated from Per Speed MAX Range and zero crossing period Per ZCrosFIt T2 Actual speed rpm Speed Range Max RPM Per Speed MAX Range Per ZCrosFIt T2 The variable Commut Rev can be used for calculation of the BLDC motor commutation period Commutation Period s 60 Actual Speed rpm Commut Rev The variable Curr Range Max cA determines scaling of the current variables So the actual dc bus current is dc bus current A Curr 256 Curr Range Max cA 100 DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 55 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Designer Reference Manual DRM028 Rev 0 56 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control Section 4 Hardware Design 4 1 Contents 4 2 System Configuration and Documentation 57 4 3 All HW Sets 64 43 All HW Sets 64 44 High Voltage Hardware Set 66 4 5 Low Voltage Evaluation Motor Hardware Set Components 70 4 6 Low Voltage Hardware Set Components 72 4 2 System Configuration and Documentation The a
113. ly two STATOR POLE 6 T b motor phases ROTOR MOVEMENT DURING ONE COMMUTATION DIRECTION OF eas ies eu PHASE CURRENT e two fast faster then the rotor can move commutations are applied to create an angular difference of the stator magnetic field and rotor magnetic field ZERO CROSSING PHASE WINDING EDGE INDICATOR The back EMF feedback is tested When the back EMF zero crossing is recognized the time of new commutation is evaluated Until at least two successive back EMF zero crossings are received the exact commutation time can not be calculated Therefore the commutation is done in advance in order to assure that successive back EMF zero crossing events would not be missed RUNNING After several back EMF zero crossing events the exact commutation time is calculated The commutation process is adjusted Motor is running with regular back EMF feedback Figure 3 18 Vectors of Magnetic Fields DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 47 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Figure 3 19 demonstrates the back EMF during the start up The amplitude of the back EMF varies according to the rotor speed During the starting back EMF acquisition state the commutation is done in advance In the running state the commutation is done at the right moments PHASE BACK EMFS BACK EMF ZERO C
114. m Freescale Semiconductor Inc Software Design State Diagram INTERRUPT INTERRUPT PWMRELOAD N TIMER 1 TIM A CH1 BEMF ZERO CROSSING SENSING ISR CURRENT MEASUREMENT ISR y START ADC DC BUS CURRENT CHANNEL SENSE ZERO CROSSING INPUT SERVE VIRTUAL TIMERS TAKE 3 ZC INPUT SAMPLES CURR VALUE FROM ADC BEMF STATE S1 amp S2 52853 IF CURR gt CURR MAX FAULT SET OVC F OVERCUR FLAG SET NEXT ADC CHANNEL NXT_CHNL po NO INTERRUPT TIMER 2 A CH3 _ COMMUTATION ISR IF CMTE_F COMMUTATION ENABLED SET ZERO CROSSING GET DO MOTOR COMMUTATION STEP SET ICR_F ZERO CROS GET TIMER 1 CURRENT SENSING TO PWM SYNCHRONIZATION SET PC PHASE COMMUTATED T_CMT TIMER 2 ACTUAL TIME BEMF state V_TASC fal edge V_TASC ris edge NO YES ZERO CROSSING SELECTION C RTI C RTI Figure 5 6 Software Flowchart Interrupts 5 5 State Diagram The motor control application can be in one of the eight states shown in Figure 5 7 Each of these states is described in the subsections following the figure DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 89 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design RESET INITIALIZE APPLICATION STAND BY STATE PWM DIS
115. mits Setting Most of voltage limit settings do not necessarily need to be done Maximal limit of dc bus voltage V CAN CHANGE 1 define VOLT MAX FAULT V 380 0 Range 0 VOLT RANGE MAX VOLT MAX FAULT V determines the maximal voltage when the drive fault state should be entered So the constants VOLT MAX FAULT V must be set according to maximal voltage limit of the motor or the power stage using the lower value Therefore the setting of this constants is also mentioned in Voltage Setting Hardware Customizing under a different label MUST IF HW CHANGE 3 It should be changed when there are problems with over voltage Minimal limit of dc bus voltage V CAN CHANGE 2 EXPER define VOLT MIN FAULT V 100 0 Range 0 VOLT RANGE MAX DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 137 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc VOLT_MIN_FAULT_V determines the minimal voltage when the drive fault state should be entered So the constants VOLT_MIN_FAULT_V must be set according to minimal voltage limits of the motor application It should be changed when there are problems with under voltage Dc bus voltage threshold mains 120V 230V V CAN CHANGE 10 define VOLT 120 THRESHOLD V 150 Range lt 0 VOLT_RANGE_MAX gt 120 V voltage threshold setting should only be used for high voltage hardware It determines if 120 or 230 V mains v
116. modify values here Figure 6 12 PC Master Software Current Parameters Tuning Window 8 Increase step by step the proportional gain CURR_PIREG_P_GAIN with PC master software until current noise or oscillation appears or up to 128 DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 141 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 15 16 18 19 20 21 Designer Reference Manual If CURR_PIREG_P_GAIN is set to 128 do further proportional gain increase CURR PIREG P GAINSCALELEFT with PC master software steps O 1 2 8 otherwise leave CURR PIREG P GAINSCALELEFT as 0 Increase step by step the integral gain PIREG GAIN with PC master software up to current oscillation or noise or up to 128 If CURR PIREG I GAIN is set to 128 do further integral gain increases to CURR PIREG GAINSCALELEFT with PC master software steps O 1 2 8 otherwise leave CURR PIREG GAINSCALELEFT as 0 You can further evaluate the setting of the regulator parameters in order to get a smoother current waveform or until the regulation seems to be performing well Open const cust x h and modify the regulator parameters with the final variable values evaluated with PC master software Change the software back to normal in code start c file label TUNING 1 remove goto modify as comment goto Align it will allow finishing Alignment state when
117. mutation time preset calculations are provided by the CmtPreset function and commutation time set calculations are provided by the CmtSet function During the Running Start or Alignment states the DecideStop function is called to check drive stop conditions and can set the Stop_F flag When the stop flag is set the MotorStop function is called to stop the motor and running start or alignment state is left The software enters stand by state Also the commutation error Cntr_Err gt MAX_ZC_ERR and over current OverCurrent flag 1 fault are checked in ERRHndl and OVCurrent functions during the Running Start or Alignment states If any error is detected the function MotorStop function is called Then the software enters Fault state through the Fault function This is only left when the failures are cleared variable Failure 0 This decision is provided DecideCleSto function called from ErrorStop In manual control the failures are cleared by setting the Start Stop switch to Stop In case of PC master software control the failures are cleared by the ClearFail flag from the software When the failures are cleared the software enters Application Initialization Besides the main loop there are three interrupts timer 1 timer 2 and PWM reload interrupts They are described in Figure 5 6 Interrupt Timer 1 is periodically called with period PER_CS_T1 The interrupt function provides dc bus current measur
118. n Harbour Centre 2 Dai King Street Tai Po Industrial Estate Tai Po N T Hong Kong 852 26668334 TECHNICAL INFORMATION CENTER 1 800 521 6274 HOME PAGE http motorola com semiconductors Information in this document is provided solely to enable system and software implementers to use Motorola products There are no express or implied copyright licenses granted hereunder to design or fabricate any integrated circuits or integrated circuits based on the information in this document Motorola reserves the right to make changes without further notice to any products herein Motorola makes no warranty representation or guarantee regarding the suitability of its products for any particular purpose nor does Motorola assume any liability arising out of the application or use of any product or circuit and specifically disclaims any and all liability including without limitation consequential or incidental damages Typical parameters which may be provided in Motorola data sheets and or specifications can and do vary in different applications and actual performance may vary over time All operating parameters including Typicals must be validated for each customer application by customer s technical experts Motorola does not convey any license under its patent rights nor the rights of others Motorola products are not designed intended or authorized for use as components in systems intended for surgical implant into the body or othe
119. nctionality as described in 68HC908MHR32 68HC9908MH16 Advance Information Motorola document order number MC68HC908MR32 D This commutation preset is provided by the function Commut In Commut the function field Set PWM P Step Cmt calls one of Shft PWMO 5 functions according to P Step Cmt value so the PVALXH registers are set as required This will not effect the PWM signals until LDOK bit is set Also the back EMF zero crossing selection preset is provided in this function by setting V variable according to P Step Cmt value 5 6 2 2 Set BLDC Commutation and BEMF Zero Crossing Selection The commutation set is provided in timer 2 interrupt function TIMACh3 Int in the code_isr c file The PWMEN is toggled and LDOK bit set in order to immediately restart the PWM generator and reload the PWM with the buffered PVAL1H PVAL1L through PVAL6H Designer Reference Manual DRMO28 Rev 0 104 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Implementation Notes PVALE6L registers Then the back EMF zero crossing selection set is provided by setting PORTF according to V_MUX variable 5 6 3 BLDC Speed Control and Calculation Desired speed calculation and PWM duty cycle setting is quite simple but there are some C language syntax tricks Also the scaling aspect needs to be taken into consideration 5 6 3 1 Desired Speed Calc
120. nsing Circuit An example of the possible implementation of the back EMF sensing circuit is shown in Figure 3 12 Designer Reference Manual DRMO28 Rev 0 36 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Brushless DC Motor Control Theory DC_BUS PHASEA PHASEB PHASE m 560k 560k 560k 560k 560k IHI AAV na 3 WN AN 560 560 560k 1 2x27k gt gt MUX ZERO CROSSING gt DETECTION Fin lt 207 Z20 lt ne SIGNAL ee e COMMAND Figure 3 12 Back EMF Sensing Circuit Diagram As explained in the theoretical part of this designer reference manual the phase zero crossing event can be detected at the moment when the branch voltage of a free phase crosses the half dc bus voltage level The resistor network is used to step down sensed voltages down to a 0 15 V voltage level The comparators sense the zero voltage difference in the input signal The multiple resistors reduce the voltage across each resistor component to an acceptable level A simple RC filter prevents the comparators from being disturbed by high voltage spikes produced by IGBT switching The multiplexer MUX selects the phase comparator output which corresponds to the current
121. nt path calibrated and checked for error e Some application system variables initialized e Some MCU peripherals are configured timer OC function PWM e PWM outputs for motor control are turned OFF Timer 1 Tim A Ch1 is synchronized with the PWM cycle e Speed input dc bus voltage and temperature measurement is initialized e Ready LED is turned ON and the state is exited 5 5 3 Stand By State diagram for this software is shown in Figure 5 8 DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 91 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Current measurement and current calibration when PWM is OFF Before testing of the start switch dc bus current is measured when PWM is OFF This way the dc bus current measurement path is calibrated The calibrated value OffsetO Curr is used for the final current calculation This offset on the ADC input should ideally be 1 65 V at 0 dc bus current If the sensed value exceeds the limit Offset Max Curr when PWM is OFF this indicates some hardware error and the control flow enters into the fault state Start condition test The start condition is tested If in manual mode PCMode 0 the start condition is a movement in the switch from stop to start In PC master software mode PCMode 1 the start condition in switch start position and StartCtrl 1 If start condition valid then Strt F
122. oftware customizing files The software pack contains the files const_cust_hv h const cust lv h and const_cust_evm h with predefined parameter settings for running on one of the optional board Software and motor hardware sets The required hardware must be Configuration selected in code fun c file by one of these files include and Parameters Where software is configuration for different customer Setting f motors the software configuration for any motor is provided in the dedicated customizing file according to the hardware board used PWM frequency 15 626 kHz with default software setting possibly changeable in const h file 2 3 2 Hardware and Drive Specifications The other system specifications are determined by hardware boards and motor characteristics The boards and their connections are shown in Section 4 Hardware Design and Section 6 User Guide 6 4 1 Hardware Configuration The hardware set specifications are discussed in the following subsections 2 3 2 1 High Voltage Hardware Set Specification This hardware set is dedicated for medium power phase current lt 2 93 A and main voltage The specifications for a high voltage hardware DRM028 Rev 0 Designer Reference Manual MOTOROLA System Description 19 For More Information On This Product Go to www freescale com Designer Reference Manual Freescale Semiconductor Inc System Description and motor set are listed in Table 2 2 The hardware operat
123. oltage will be detected by software But the VOLT 120 THRESHOLD V detection has no importance for the software functionality For low voltage hardware the VOLT 120 THRESHOLD V should be set to O 6 5 4 2 Maximal and Minimal Current Limits Setting Most of current limits settings do not necessarily need to be done Current offset limit for fault during calibration initialization V CAN CHANGE 4 define OFFSET MAX CURR V 1 65 0 225 Range 0 5 When PWM is off the default hardware determined offset should be 1 65 V The actual offset is checked during current calibration The fault offset limit should be OFFSET MAX CURR V Default h w offset minimal allowed offset error EQ 6 3 OFFSET MAX CURR V should only be changed if there are over current problems during current offset calibration at MCU initialization Maximal limit of dc bus current A CAN CHANGE 3 define CURR MAX FAULT A 1 5 Range 0 CURRENT RANGE MAX A Designer Reference Manual DRMO28 Rev 0 138 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor CURR_MAX_FAULT_A should be changed for a motor with maximal allowable current lower than the board Initial value for OVer Current Counter CAN CHANGE 5 define I_CNTR_OVC 0x04 Range lt 0 255 gt CNTR OVC determines the number of current samples with curren
124. onnected Not Connected RS232 emulator Figure 6 1 High Voltage Hardware System Configuration NOTE Itis strongly recommended to use opto isolation optocouplers and optoisolation amplifiers during development time to avoid any damage to the development equipment NOTE Allthe system parts are described in Section 4 Hardware Design They can be ordered as a standard products For the the supply and in detail document references shown see section 4 2 1 High Voltage Hardware Set Configuration 6 4 1 2 Low Voltage Evaluation Motor Hardware Set Configuration The system configuration for a low voltage evaluation motor hardware set is shown in Figure 6 2 Designer Reference Manual DRMO28 Rev 0 114 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Application Hardware and Software Configuration PC Computer RS232 PC Master 40w flat 12 GND Controller Board HC908MR32 ECCTR908MR32 Motor EVM1 ECMTREVAL Evaluation Motor Board 12VDC 3 M1 KITMMDSO8MR32 IB23810 PC Computer RS232 emulator Figure 6 2 Low Voltage Evaluation Motor Hardware System Configuration NOTE Allthe system parts are described in section Section 4 Hardware Design They can be ordered as a standard products For the the supply and in detail document references shown see section 4 2 2 Low Voltage
125. onstration suitcase communication commands PC master software BLDC demonstration suitcase communication bytes After reset the BLDC control MCU software is in manual mode In order to control the system from PC master software it is necessary to set PC master software mode and then to provide the MCU software control from PC master software via application interface variables 3 4 1 2 PC Master Software BLDC Control MCU Software API Communication Commands DRM028 Rev 0 Commands defined for the BLDC control MCU software are listed in Table 3 1 The commands are very simple If the software executes the command it responds with OK byte OO If it is unable to execute the command it responds with failed code 55 The commands Set PC master software mode Set manual mode can only be executed when the START STOP switch on the demonstration suitcase is set to STOP and the motor is stopped Otherwise a failed response is sent Table 3 1 PC Master Software Communication Commands Comman Data Respon Response Command d Byte s Descriptio Suitcase Action Code s Byte n Set PC master 01 Nore Setting of PC master 00 OK software mode software mode 55 Failed 1 Microsoft is a registered trademark of Microsoft Corporation in the United States and or other countries Designer Reference Manual MOTOROLA BLDC Motor Control 51 For More Information On This Product Go to
126. orates a 3 phase High Voltage BLDC motor and attached BLDC motor brake The BLDCmotor has six poles The incremental position encoder is coupled to the motor shaft and position Hall sensors are mounted between motor and brake They allow sensing of the position if required by the control algorithm Detailed motor brake specifications are listed in Table 2 2 Section 2 4 5 Low Voltage Evaluation Motor Hardware Set Components 4 5 1 EVM Motor Board Designer Reference Manual Motorola s embedded motion control series EVM motor board is a 12 volt 4 amp surface mount power stage that is shipped with an MCG IB23810 H1 brushless dc motor In combination with one of the embedded motion control series control boards it provides a software development platform that allows algorithms to be written and tested without the need to design and build a power stage It supports algorithms that use Hall sensors encoder feedback and back EMF electromotive force signals for sensorless control The EVM motor board does not have overcurrent protection that is independent of the control board so some care in its setup and use is required if a lower impedance motor is used With the motor that is supplied in the kit the power output stage will withstand a full stall condition without the need for overcurrent protection Current measuring circuitry is set up for 4 amps full scale In a 25 C ambient operation at up to 6 amps continuous RMS output current is
127. ortant role here The difference of the mutual inductances between the coils which carry the phase current and the coil used for back EMF sensing causes the PWM pulses to be superimposed onto the detected back EMF voltage In fact it is produced by the high rate of change of phase current transferred to the free phase through the coupling of the mutual inductance Figure 3 7 shows the real measured branch voltage The red curves highlight the effect of the difference in the mutual inductances This difference is not constant DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 31 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control NOTE CAUTION Designer Reference Manual Figure 3 7 Mutual Inductance Effect Due to the construction of the BLDC motor both mutual inductances vary They are equal at the position that corresponds to the back EMF zero crossing detection The branch waveform detail is shown in Figure 3 8 Channel 1 in Figure 3 8 shows the disturbed branch voltage The superimposed ripples clearly match the width of the PWM pulses and thus prove the conclusions from the theoretical analysis The effect of the mutual inductance corresponds well in observations carried out on the five different BLDC motors These observations were made during the development of the sensorless technique The BLDC motor with stator
128. os Chi gv Figure 3 10 Distributed Back EMF by Unbalanced Capacity Coupling Channel 1 in Figure 3 11 shows the disturbed branch voltage while the other phase channel 2 is not affected because it faces balanced mutual capacitance The unbalance was purposely made by adding a small capacitor on the motor terminals in order to better demonstrate the effect After the unbalance was removed the branch voltage is clean without any spikes DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 35 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Tek Single Seq 2 50MS s PEN 4 Ch22oom 1 0XVert 0 1 Tm Chi 5 00V Mig 5 00V 200gs Ch247 8V Figure 3 11 Balanced Capacity Coupling NOTE Theconfiguration of the phase windings end turns has significant impact therefore it needs to be properly managed to preserve the balance in the mutual capacity This is important especially for prototype motors that are usually hand wound CAUTION Failing to maintain balance in the mutual capacitance can easily disqualify such a motor from using sensorless techniques based on the back EMF sensing Usually the BLDC motors with windings wound on separate poles show minor presence of the mutual capacitance Thus the disturbance is also insignificant 3 2 5 Back EMF Se
129. ossing is not captured If the back EMF zero crossing is captured before the preset commutation time expires then the exact calculation of the commutation time T2 n is made based on the captured zero crossing time T ZCros n The new commutation is performed at this new time If for any reason the back EMF feedback is lost within one commutation period corrective actions are taken in order to return to the regular states The flowchart explaining the principle of BLDC commutation control with back EMF zero crossing sensing is shown in Figure 3 16 Designer Reference Manual MOTOROLA BLDC Motor Control 41 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control COMMUTATION DONE BEMF ZERO CROSSING DETECTED BETWEEN PREVIOUS COMMUTATIONS CORRECTIVE CALCULATION 1 YES m SERVICE OF COMMUTATION PRESET COMMUTATION WAIT FOR PER_TOFF UNTIL PHASE CURRENT DECAYS TO ZERO BEMF ZERO CROSSING MISSED BEMF ZERO CROSSING DETECTED HAS COMMUTATION TIME EXPIRED YES BEMF ZERO CROSSING MISSED CORRECTIVE CALCULATION 2 CORRECTED SETTING OF COMMUTATION TIME SERVICE OF RECEIVED BEMF ZERO CROSSING CORRECTED SETTING OF COMMUTATION TIME Y HAS COMMUTATION TIME EXPIRED MAKE MOTOR COMMUTATION Figure 3 16 BLD
130. parameters tuning e PC master software oscilloscope windows with required variables The remote application control uses the same control page as described in PC Master Software Remote Operating Mode Moreover the tuning file incorporates subprojects for a dedicated system variables DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 129 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc setting and PC master software oscilloscope windows for watching dedicated parameters variables NOTE For software parameter tuning with PC master software it is necessary to have PC master software installed on your PC computer click here for Current click here for Start click here for Speed Parameters Tuning Parameters Tuning Parameters Tuning if tuning_bldc mp PCMaster l8 x DLDC motor on HC9USMK iv PC Master Mode Bh Mew Scop Start Stop Motor Motor Running jou c 1395 rpm 1400 rpm DC bus current 95 mA comm period 3 585 us Temperature Real Failures speed 1 395 rpm comm period 3 585 us 400 rpm click here Identified hardware to display Power stage board Not recognized control page Optoisolation board Not recognized CPU HC908MR32 value Unit 01 PCMasterMode CURR ALIGN A 0 485322 CURR HW MAX A 100 02 command 010 Actual Current 0 0118371
131. pplication is designed to drive the 3 phase BLDC motor The HW is a modular system composed from board and motor There are three possible hardware options High Voltage Hardware Set Configuration e Low Voltage Evaluation Motor Hardware Set Configuration e Low Voltage Hardware Set Configuration The following subsection shows the system configurations They systems consists of the following modules see also Figure 4 1 Figure 4 2 Figure 4 3 For all hardware options e MC68HC908MR32 Control Board For High Voltage Hardware Set cofiguration DRM028 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 57 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design e 3 Phase AC BLDC High Voltage Power Stage e Optoisolation Board e 3 phase BLDC High Voltage Motor with Motor Brake For Low Voltage Evaluation Motor Hardware Set configuration EVM Motor Board e 3 Low Voltage EVM BLDC Motor Low Voltage Hardware Set configuration 3 Ph AC BLDC Low Voltage Power Stage e 3 phase BLDC Low Voltage Motor with Motor Brake The supplied controller boards for MC68HC908MR32 ECCTRMR32 allows two possibilities for software execution 1 MMDS Evaluation Board KITMMDSMR32 Using a real time debugger supplied with the Metrowerks compiler the evaluation board is connected to the controller board ECCTRMR32 via an emulator connector This solution is re
132. r applications intended to support or sustain life or for any other application in which the failure of the Motorola product could create a situation where personal injury or death may occur Should Buyer purchase or use Motorola products for any such unintended or unauthorized application Buyer shall indemnify and hold Motorola and its officers employees subsidiaries affiliates and distributors harmless against all claims costs damages and expenses and reasonable attorney fees arising out of directly or indirectly any claim of personal injury or death associated with such unintended or unauthorized use even if such claim alleges that Motorola was negligent regarding the design or manufacture of the part MOTOROLA Motorola and the Stylized M Logo are registered in the U S Patent and Trademark Office digital dna is a trademark of Motorola Inc All other product or service names are the property of their respective owners Motorola Inc is an Equal Opportunity Affirmative Action Employer Motorola Inc 2003 DRMO28 D For More Information On This Product Go to www freescale com
133. ration All the system parts are supplied and documented according to the following references e EVM1 Modular Development System with EM08MR32 Daughter Board Supplied as KITMMDSO8MR32 Described in Manual supplied with kit e 01 Controller Board for MC68HC908MR32 Supplied as ECCTR908MR32 DRMO028 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 59 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design NOTE Designer Reference Manual Described in MC68HC908MR3 2 Control Board User s Manual Motorola document order number MEMCMR32CBUM D see References 3 e 02 3 Phase AC BLDC High Voltage Power Stage Supplied in kit with optoisolation board as ECOPTHIVACBLDC Described in 3 Phase AC Brushless DC High Voltage Power Stage User s Manual Motorola document order number MEMC3PBLDCPSUM D see References 4 e U3 Optoisolation Board Supplied with 3 phase AC BLDC high voltage power stage as ECOPTHIVACBLDC Or supplied alone as ECOPT ECOPT optoisolation board Described in Optoisolation Board User s Manual Motorola document order number MEMCOBUM D see References 5 It is strongly recommended to use opto isolation optocouplers and optoisolation amplifiers during development time to avoid any damage to the development equipment e MB1 Motor Brake SM40V SG40N Supplied as E
134. reescale Semiconductor Inc NOTE NOTE Remember the MMDS MCU clock must be set to 4 MHz Change the crystal oscillator or set oscillator W1 to MMDS and set 4 MHz in the real time debugger MMDS0508 arget signals 4 MHz Once the application is running move the RUN STOP switch to the RUN position and set the required speed with the SPEED potentiometer If successful the BLDC motor will be spinning If the RUN STOP switch is set to the RUN position when the application starts toggle the RUN STOP switch between the STOP and RUN positions to enable motor spinning This is a protection feature that prevents the motor from starting when the application is executed from CodeWarrior 6 4 3 3 Execute from Pre programmed MCU NOTE When the software is built the S record file bldc zerocros08mr32 MMDS sx is generated in oldc_zerocrosO8MR32 bin bldc_zerocrosO8mr32_ MMDS sx The software must be built see Build to generate by linker the bldc zerocros08mr32 MMDS sx file last update This S record file can be used for programming of MC68HC908MR32 MCU devices An external programmer e g Motorola M68HCOS8 serial programmer must be used to program the device The programmed MCU with MC68HC908MR32 daughter board module can then be plugged into the controller board ECCTRMR32 instead of the emulator cable 6 4 4 Application Control Designer Reference Manual This BLDC sensorless motor control application can opera
135. reescale Semiconductor Inc e bidc_zerocrosO8MR32 sources ram c general RAM definitions e bIdc_zerocrosO8MR32 sources ram h general RAM declarations header e bIdc_zerocrosO8MR32 sources ram_bit h general RAM bits definitions header e bIdc_zerocrosO8MR32 sources ram_cust_param c RAM variables for software customizing definitions e bIldc_zerocrosO8MR32 sources ram_cust_param h RAM variables for software customizing header declarations e bldc_zerocrosO8MR32 sources tab_cust c constants tables definitions e bldc_zerocrosO8MR32 sources tab_cust h constants tables definitions header bldc_zerocrosO8MR32 sources pcmaster c PC master software communication subroutines e bIldc_zerocrosO8MR32 sources pcmaster h PC master software communication subroutines header e Abldc zerocros08MR32Nsourcesicode asm asm program assembler functions e bIdc_zerocrosO8MR32 sources code_asm h program assembler functions header e bIdc_zerocrosO8MR32 prms default prm linker command file 6 4 2 2 Application PC Master Software Control Files The application PC master software control files are e bildc_zerocrosO8MR32 pc_master BLDC pmp PC master software project file e bIdc_zerocrosO8MR32 pc_master source directory with PC master software control page files Designer Reference Manual DRMO28 Rev 0 120 User Guide MOTOROLA For More Information On This Product Go to
136. rement Handler The measurement handler assures that the measurement process is done in the right order The dc bus voltage speed command and temperature are scanned sequentially After the state has run three times all the values for dc bus current dc bus voltage speed input and temperature are updated dc bus current is scanned with a constant time period in the current measurement ISR but the over current condition is evaluated in the main software loop After a defined number I OVC Cnt of successive over current events the control flow enters into the fault state The BLDC motor is run with regular feedback The speed controller is used to control the motor speed by changing the value of PWM duty cycle Figure 5 11 shows the state transitions Measurements Handler Explained in 5 5 5 Back EMF Acquisition State Service of Commutation Explained in 5 5 5 Back EMF Acquisition State Service of Received Back EMF Zero Crossing Designer Reference Manual MOTOROLA Software Design 99 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design Explained in 5 5 5 Back EMF Acquisition State The difference is that the commutation parameters are recalculated with different constants see 3 3 1 3 Running Commutation Time Calculation BEMF Zero Crossing Interrupt Service Routine Explained in 5 5 5 Back EMF Acquisition State Current Measurement Interrupt Service
137. rence Manual DRMO28 Rev 0 38 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Used Control Technique position is known and can be used to calculate the speed and processing of the commutation in the running state C START MOTOR ALIGNMENT ALIGNMENT TIME EXPIRED STARTING BACK EMF ACQUISITION MINIMAL CORRECT COMMUTATIONS DONE YES RUNNING Figure 3 14 Commutation Control Stages 3 3 1 1 Alignment Before the motor starts there is a short time depending on the motor s electrical time constant when the rotor position is stabilized by applying PWM signals to only two motor phases no commutation The current controller keeps current within predefined limits This state is necessary in order to create a high start up torque When the preset time out expires then this state is finished DRM028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control The current controller subroutine with PI regulator is called to control dc bus current It sets the correct PWM ratio for the required current The current PI controller works with constant execution sampling period This period should be a multiple of
138. roller software to identify the power board Power requirements for controller side circuitry are met with a single external 12 Vdc power supply Power for power stage side circuitry is supplied from the power stage through the 40 pin output connector 4 4 2 1 Electrical Characteristics of the Optoisolation Board The electrical characteristics in Table 4 3 apply to operation at 25 C and a 12 Vdc power supply voltage Table 4 3 Electrical Characteristics Characteristic Symbol Min Typ Max Units Notes Power Supply Voltage Vdc 10 12 30 V Quiescent Current lec 700 2000 500 mA dc dc converter Min Logic 1 Input Voltage 2 0 V HCT logic Max Logic 0 Input Voltage 0 8 V HCT logic Analog Input Range Vin 0 3 3 V Input Resistance Rin 10 Analog Output Range Vout 0 3 3 V Digital Delay Time 0 25 us Analog Delay Time tADLY 2 us 1 Power supply powers optoisolation board only 2 Current consumption of optoisolation board plus DSP EMV board powered from this power supply 3 Maximum current handled by dc dc converters DRMO28 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 69 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Hardware Design 4 4 3 3 phase BLDC High Voltage Motor with Motor Brake The High Voltage BLDC motor brake set incorp
139. rrent Parameters Tuning 2 New cope Actual Current CURR ALIGN A 51 19 2 Start eters Tuning E New 5 050 3 5peed lt Tuning 6 New Scope 045 0 10 click here to display TT TTTT 0 05 E 0 00 516450 515500 516 516600 516650 516700 516750 516800 516850 516900 516950 Time ms Value Unit 01 PCMasterMode 10 485322 CURR HW MAX 02 command 010 Actual Current 0 0118371 CURR Hw MAX A 02 ManualMode CURR PIREG P GAIN DEC CURR PIREG P GAINSCALE DEC PIREG I GAIN DEC CURR_PIREG_I_GAINSCALE DEC PER_T_ALIGN_MS StartStop COM4 speed 9600 bps Scope Bad modify values here Figure 6 11 PC Master Software Parameters Tuning Control Window DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 131 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc NOTE The software parameters can be temporarily modified and evaluated using the PC master software tuning file But the parameter settings are not stored in the non volatile memory after reset the software loads parameters from const_cust_x h file When you finish the software parameters evaluation you must open one of the const_cust_hv h const cust evmm h and const cust lv h files and manually modify the paramete
140. rs according to the final variable values evaluated otherwise you will get default setting after the MCU reset 6 5 2 Software Parameters Setting Follow up The software is provided with three parameters sets files const cust hv h const cust evmm h and const cust lv h configured for three hardware and motor kits HV LV and EVM as was described before But the software can be configured for other 3 phase trapezoidal BLDC motors or possibly other hardware board parameters The motor control drive usually needs setting tuning for e Current voltage parameters e Dynamic parameters The parameter configurations must be set in source code before compilation However some parameters can also be temporarily changed using PC master software experimental setting Finally when an appropriate parameter value is found it can be set in the source code The software parameters settings are described in the subsections below and in the software code by comments You should proceed with some steps to customize the software according to your motor or hardware characteristics The source code is commented with descriptive labels to simplify the process 6 5 2 1 Labels in the Files const cust hv h const cust evm h const cust lv h Designer Reference Manual Most of the software parameter settings are provided in one of these files const cust hv h const cust evmm h or const cust lv h The required steps are marked DRMO28
141. s 5 W 4 5 2 3 phase Low Voltage EVM BLDC Motor The EVM Motor Board is shipped with an MCG IB23810 H1 brushless dc motor Motor brake specifications are listed in Table 2 3 Section 2 Other detailed motor characteristics are in Table 4 5 this section They apply to operation at 25 C Table 4 5 Characteristics of the BLDC motor Characteristic Symbol Min Typ Max Units Terminal Voltage Vi 60 V Speed V 5000 RPM Torque Constant 0 08 Nm A DRMO28 Rev 0 Designer Reference Manual MOTOROLA Hardware Design For More Information On This Product Go to www freescale com 71 Freescale Semiconductor Inc Hardware Design Table 4 5 Characteristics of the BLDC motor Voltage Constant Ke 8 4 V kKRPM Winding Resistance 2 8 Q Winding Inductance L 8 6 m mH Continuous Current lcs 2 A Peak Current los 5 9 A Inertia dis 0 075 kgcm Thermal Resistance 3 6 C W 4 6 Low Voltage Hardware Set Components 4 6 1 3 Ph AC BLDC Low Voltage Power Stage Designer Reference Manual Motorola s embedded motion control series low voltage LV brushless DC BLDC power stage is designed to run 3 ph BLDC and PM Synchronous motors It operates from a nominal 12 volt motor supply and delivers up to 30 amps of rms motor current from a dc bus that c
142. sign in order to be able to measure negative and positive current values The status registers are initialized and PWM generator is started Also timer 1 is started at the right moment to be synchronized with the PWM generator This way the current measurement is executed at the defined moment of the PWM signal Designer Reference Manual MOTOROLA Software Design 83 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design MCU INITIALIZATION SYSTEM REGISTERS INITIALIZATION PORTS INITIALIZATION PLL CPU CLOCK INITIALIZATION PCMASTER SOFTWARE PORT INITIALIZATION APPLICATION INITIALIZATION CURRENT OFFSET CALIBRATION SYSTEM REGISTERS INITIALIZATION PWM INITIALIZATION TIMER 1 CURRENT SENSING TO PWM SYNCHRONIZATION ADC MEASUREMENT INITIALIZATION MAIN S W LOOP SEEFIGURE 5 5 Figure 5 4 Main Software Flowchart In the Stand By state function the start stop switch is checked using StSWReadStart function The DecideStaSto function is called to decide if the application should start The start condition differs if manual or PC master software mode is set When in manual mode PCMode 0 the start condition is the switch in the start position When PC master software mode PCMode 1 the start condition is a start request from PC master software StartCtrl 1 In both modes Stop F is cl
143. t commutation period PER CMT START US period must be changed for any motor accommodation It can be set experimentally If the motor displays errors during Starting Back EMF Acquisition state beginning DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 145 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Running state or has a low start up torque DO decrease or increase the PER_CMT_START_US value Table 6 2 shows typical setting examples Must be PER_CMT_START_US lt PER_CMT_MAX_US 2 NOTE Setting this constant is an empirical process It is difficult to use a precise formula because there are many factors involved which are difficult to obtain in the case of a real drive motor and load mechanical inertia motor electromechanical constants and sometimes also the motor load So they need to be set with a specific motor PER_CMT_START_US can be evaluated with PC master software tuning file tuning bldc pmp Table 6 2 Start up Period First to Seco Second to Thi Typical rd Motor Size ee E Commutation Commutation Step Period Step Period Slow motor high load and 8000 0 us 8 ms 8 16 ms motor mechanical inertia Fast motor high load and 2000 0 us Bie Dd Wis motor mechanical inertia Maximal commutation period limit us CAN CHANGE 6 EXPER define PER CMT MAX US 65536 0 Range 0 65535 UNIT PERIOD
144. t value CURR MAX FAULT A needed before entering the drive fault state The current sampling period is PER CS T1 US 128 us at default software and PWM frequency setting CNTR_OVC should normally not be changed Lower value of CNTR OVC secures a fast safer over current switch off High value of I CNTR secures an unexpected over current switch off 6 5 4 3 Alignment Current and Current Regulator Setting The current during alignment state before motor starts A MUST CHANGE 1 EXPER define CURR ALIGN A 0 55 Range 0 CURRENT RANGE MAX A It is recommended that nominal motor current value be set Sometimes when power source is not able to deliver the required current it is necessary to set a lower value then nominal motor current NOTE CUHRR ALIGN A can be evaluated with PC master software tuning file tuning bldc pmp It might also be necessary to set the current PI regulator constants MUST CHANGE 2 EXPER define CURR PIREG P GAINSCALELEFT 0 Range 0 8 MUST CHANGE 3 EXPER define CURR PIREG P GAIN 128 Range 0 255 where the current regulator proportional gain is KP CUR PIREG P GAIN 2CURR OUREG P GAINSCALELEFT E 6 4 MUST CHANGE 4 EXPER DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 139 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc NOTE Designer Reference Manual define CUR
145. te in two modes 1 Manual Operating Mode 2 PC Master Software Remote Operating Mode DRMO28 Rev 0 122 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Application Hardware and Software Configuration 6 4 4 1 Manual Operating Mode In the manual operating mode the drive is controlled by the RUN STOP switch and the required speed is set by the SPEED potentiometer The RUN STOP switch enables disables motor spinning The yellow LED will light whenever the application software correctly executes so it will also light when motor spinning is disabled or at a fault state When motor spinning is enabled and starts spinning alignment or starting back EMF acquisition state only the yellow LED lights When motor rotation is enabled and the motor runs with speed closed loop running state the green LED lights yellow LED also lights e over current or over voltage fault occurs the internal fault logic is asserted and the application enters a fault state indicated by a red LED blinking yellow LED lights This state can be exited only by an application RESET or setting RUN STOP switch to STOP NOTE Itis strongly recommended that you inspect the entire application to locate the source of the fault before starting again 6 4 4 2 PC Master Software Remote Operating Mode In the PC master software remote operating mode the
146. ts Handler As explained in Scheduler and Over Current Detection the dc bus current is scanned and over current condition is evaluated Where there is an over current the control enters the fault state see Fault State The voltage and the speed commands are scanned too When this state is finished the values of dc bus current dc bus voltage and speed command are updated Designer Reference Manual DRMO28 Rev 0 96 Software Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design State Diagram PWM DUTY CYCLE IS LEFT AT VALIE FOUND BY THE CURRENT CONTROLLER DURING THE ALIGN STATE FIRST COMMUTATION COMMUTATIONS ARE LOCKED TO THE BACK BMF FEEDBACK DONE START_F 0 CURRENT MEASUREMENT IS DONE SECOND COMMUTATION CMD_F 1 CURRENT MEASUREMENT DONE IS DONE DONE MEASUREMENTS HANDLER MEASUREMENTS HANDLER ERROR HANDLER DONE PHASE HAS BEEN COMMUTATED PC_F 1 DONE RECEIVED THE ZERO CROSSING EVENT DONE ICR_F 1 DONE SERVICE OF COMMUTATION SERVICE OF RECEIVED BACK EMF ZERO CROSSING FEEDBACK IRRECOVERABLE COMMUTATION ERROR IRRECOVERABLE OVER CURRENT 2 TIM A CH3 INTERRUPT PWM RELOAD INTERRUPT PWM CENTER vet COMMUTATION ISR TIMER TIM A CH1 INTERRUPT BEMF ZERO CROSSING P ad SENSING ISR PHASE HAS BEEN CURRENT MEASUREMENT MER BN IS DONE
147. tting 6 5 6 Software Customizing to Motor Speed Control Setting Accomplishing the above steps should be sufficient for most applications However in some cases there may be a need for advanced software customizing see Figure 6 8 with changes to motor PWM Designer Reference Manual DRMO28 Rev 0 126 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor frequency or to the current regulator sampling period as explained in the section 6 5 7 PWM Frequency and Current Sampling Period Setting If there s still a problem running the motor check if the motor is suitable for sensorless control with back EMF zero crossing see Figure 6 9 as described in the section 6 2 4 Motor Suitability Then again check the application suitability DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 127 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Decision on the Application Suitability CHECK MINIMAL APPLICATION SPEED CHECK MAXIMAL MOTOR SPEED OK Selection of the Power Stage HV EVM LV INCLUDE INCLUDE INCLUDE CONST CUST CONST CUST EVMM H CONST INTO CODE FUN C FILE INTO CODE FUN C FILE INTO CODE FUN C FILE Modified H W INCLUDE APPROPRIATE CONS
148. uitability Guide since the Designer Reference Manual DRMO28 Rev 0 158 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Tuning for Customer Motor software may not be suitable for some applications Some important recommendations can also be found under the Caution and Note labels in this designer reference manual DRMO028 Rev 0 Designer Reference Manual MOTOROLA User Guide 159 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual DRMO28 Rev 0 160 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control DRM028 Rev 0 Appendix A References Sensorless BLDC Motor Control on MC68HC908MR32 Software Porting to Customer Motor document order number AN2356 D Motorola 2002 Motion Control Development Tools found on the World Wide Web at http e www motorola com Motorola Embedded Motion Control MC68HC908MR32 Control Board User s Manual document order number MEMCMR32CBUM D Motorola 2000 Motorola Embedded Motion Control 3 Phase AC BLDC High Voltage Power Stage User s Manual document order number MEMC3PBLDCPSUM D Motorola 2000 Motorola Embedded Motion Control Optoisolation Board document order number MEMCOBUM D
149. ulation The 8 bit value Speed_Desired is calculated using 8 bit multiplication of two 8 bit variables Sp_Input and Coef Speed Inp The syntax is unsigned char Sp_Input Coef_Speed_Inp gt gt 8 This syntax is used to generate optimal code using the MUL instruction 5 6 3 2 PWM Duty Cycle PWM duty cycle is set for all six PWM channels according to regulators output OutReg U8 The maximal duty cycle is at OutReg_U8 255 The registers PVAL1H PVAL1L through PVAL6H PVAL6L are set proportionally to the PWM modulus register PMOD MCPWM MODULUS constant 100 duty cycle is when PVALx PMOD The PWM Val Max variable is PWM Val Max DUTY MAX MCPWM MODULUS This variable is used for scaling of the regulator output OutReg U8 The registers PVAL1H PVAL1L through PVAL6H PVAL6L are loaded with PWM Val calculated from OutReg U8 PWM Val Val Max OutReg U8 256 This calculation is provided with macro umul 16x8 macro DRMO028 Rev 0 Designer Reference Manual MOTOROLA Software Design 105 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Software Design 5 6 4 Timers Timer 1 and timer 2 are implemented using MC68HCO8MR32 timers Timer 3 is a software virtual timer using time base of timer 1 5 6 4 1 Timer 1 Timer 1 is provided by timer A channel 1 set in output compare mode In this mode the registers TACH1H and TACH1L are used for setting the output compare
150. unsigned int BoardIdFail 1 BIT6 pcb Identification Failure unsigned int ErrCmt 1 BIT7 error Commutation B ErrCmt VoltageFailure OverHeating OverCurrent ay char R Failure Def Failure Flags register Definition Table 3 2 declares if the variable is used as an output or input from the BLDC control MCU software side The variable is described and the unit defined When PC master software mode is set the system start and stop is controlled by StartCtrl flag in Motor Ctrl variable When the application enters the fault state the variable Failure displays the fault reason Setting the ClearFail flag in Motor Ctrl will exit the fault state Designer Reference Manual DRMO28 Rev 0 54 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Application Control The Sp_Input variable is used for speed control In PC master software mode it can be modified from PC master software otherwise it is set according to speed potentiometer value Desired speed rpm Sp_Input 255 Speed_Max_RPM Speed_Min_RPM Speed_Min_RPM So the required motor commutation period is determined by the Speed_Max_RPM and Speed_Min_RPM variables These are chosen according to which optional board and motor set by the BLDC control MCU software The variable Speed_Range_Max_RPM determines scaling of the speed variab
151. upplied as ECMTRLOVBLDC The individual modules are described in some sections below More detailed descriptions of the boards can be found in comprehensive User s Manuals belonging to each board References 3 7 These manuals are available on on the World Wide Web at http www motorola com The User s Manual incorporates the schematic of the board description of individual function blocks and a bill of materials An individual board can be ordered from Motorola as a standard product 4 3 All HW Sets Components 4 3 1 MC68HC908MR32 Control Board Motorola s embedded motion control series MR32 motor control board is designed to provide control signals for 3 phase ac induction 3 phase brushless dc BLDC and 3 phase switched reluctance SR motors In combination with one of the embedded motion control series power stages and an optoisolation board it provides a software development platform that allows algorithms to be written and tested without the need to design and build hardware With software supplied on the CD ROM the control board supports a wide variety of algorithms for ac induction SR and BLDC motors User control inputs are accepted from START STOP FWD REV switches and a SPEED potentiometer located on the control board Alternately motor commands can be entered via a PC and transmitted over a serial cable to DB 9 connector Output connections and power stage feedback signals are grouped together on 40 pin ribbon ca
152. ure 3 5 The power stage is usually controlled by a dedicated microcontroller with on chip PWM module 3 2 3 Why Sensorless Control As explained in the previous section rotor position must be known in order to drive a brushless dc motor If any sensors are used to detect rotor position sensed information must be transferred to a control unit see Figure 3 4 Therefore additional connections to the motor are necessary This may not be acceptable for some applications see 1 3 Benefits of the Solution AC LINE VOLTAGE POWER STAGE M POSITION LOAD A SENSORS CONTROL SIGNALS SPEED POSITION FEEDBACK SETTING gt CONTROL UNIT MOTOR DRIVE Figure 3 4 Classical System 3 2 4 Power Stage Motor System Model In order to explain and simulate the idea of back EMF sensing techniques a simplified mathematical model based on the basic circuit topology has been created See Figure 3 5 DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 27 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control URa Figure 3 5 Power Stage Motor Topology The second goal of the model is to find how the motor characteristics depend on the switching angle The switching angle is the angular difference between a real switching event and an ideal one at the point where
153. value T1 TACNTH and TACNTL form a 16 bit timer A counter with an infinite counting 16 bit roll over e The timer A channel 1 interrupt is called whenever TACH1H TACNTH and TACH1L TACNTL With each interrupt the registers TACH1H and TACH1L are loaded with the new value T1 T1 PER CS T1 where T1 PER CS Tl is a 16 bit addition with no saturation So the constant interrupt period PER CS T1 of the timer T1 interrupts is generated e The timer unit UNIT PERIOD T1 US of timer A is determined by the MCU bus frequency 8 MHz with a 4 MHz oscillator and default software setting and timer prescaler set in TASC So the default software value is 2 us The timer 1 interrupt function is provided by the TIMACh1 Int function 5 6 4 2 Timer 2 Timer 2 is provided by timer A channel 3 set in output compare mode In this mode the registers TACH3H and are used for setting the output compare value T2 TACNTH and TACNTL form a 16 bit timer A counter with infinite counting 16 bit roll over e The actual time is sensed from TACNTH and TACNTL base e g time of the commutation T Cmt e The timer A channel 3 timer 2 interrupt is called whenever TACNTH and TACH3L TACNTL So the registers and are loaded with the T2 variable value Designer Reference Manual DRMO28 Rev 0 106 Software Design MOTOROLA For More Information On This Product Go to www freescale com
154. ve SPEED_PIREG_P_GAINSCALELEFT as 0 Increase step by step the integral gain SPEED_PIREG_I_GAIN with PC master software up to current oscillation or noise or up to 128 If SPEED_PIREG_I_GAIN is set to 128 do further integral gain increases to SPEED_PIREG_I_GAINSCALELEFT with PC master software steps 6 5 4 0 otherwise leave SPEED_PIREG_I_GAINSCALELEFT as 7 You can further evaluate the setting of the regulator parameters in order to get a smoother current waveform until the regulation seems to be performing well Open const cust x h and modify the regulator parameters with the final variable values evaluated with PC master software Start motor see Application Control and PC Master Software Remote Operating Mode Set minimal desired speed If the displayed real speed is not able to go down to the desired minimal speed it is necessary to decrease minimal PWM duty cycle DUTY PWM MIN in const cust x h Then you can tune dynamic characteristics of speed regulators steps 22 to 29 or finish tuning the regulators Start motor see Application Control and PC Master Software Remote Operating Mode Designer Reference Manual MOTOROLA User Guide 155 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 22 Set minimal speed 23 Set maximal speed and observe the speed transient 24 Set minimal speed and observe the speed transient 25 Then modify the regulator param
155. voltage Vit 0 8 V Analog output range Vout 0 3 3 V Bus current sense voltage Isense 33 mV A Bus voltage sense voltage VBus 60 mV V been T current ine _ __ 46 Continuous output current IRMs 30 A D dissipation Pu m m 50 W a dissipation __ __ 100 Total power dissipation Puiss 85 W 4 6 2 3 phase BLDC Low Voltage Motor with Motor Brake The Low Voltage BLDC motor brake set incorporates a 3 phase Low Voltage BLDC motor EM Brno SM40N and attached BLDC motor brake SG40N The BLDCmotor has six poles The incremental position encoder is coupled to the motor shaft and position Hall sensors are mounted between motor and brake They allow sensing of the position if required by the control algorithm which is not required in this sensorless application Detailed motor brake specifications are listed in Table 2 4 Section 2 Designer Reference Manual DRMO28 Rev 0 74 Hardware Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc Designer Reference Manual Sensorless BLDC Motor Control 5 1 Contents 5 2 Introduction 5 3 Data Flow DRM028 Rev 0 Section 5 Software Design ie oh FCR QUERER E doE dp dA ce I SOR kids ee 11 2112127 CUTEM 54 Main Software Flowchart 55 4555 lt
156. ware With default software settings and COEF_HLFCMT 0 450 it is 333 us as shown in Table 2 1 So for example the 4 pole 3 phase motor can be controlled up to the maximal speed of 15 015 rpm Using PC master software in the application increases the minimal commutation time This is due to the execution of PC master software routine In this case the minimal execution time is 520 ms The minimal commutation period could be decreased using pure assembler code instead of C coding 6 2 3 Voltage Closed Loop As shown in Application Hardware and Software Configuration the speed control is based on voltage closed loop control This should be sufficient for most applications 6 2 4 Motor Suitability Designer Reference Manual Back EMF zero crossing sensing is achievable for most of BLDC motors with a trapezoidal back EMF However for some BLDC motors the back EMF zero crossing sensing can be problematic since it is affected by unbalanced mutual phase capacitance and inductance It can disqualify some motors from using sensorless techniques based on the back EMF sensing DRMO28 Rev 0 110 User Guide MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc User Guide Application Suitability Guide 6 2 4 1 Effect of Mutual Phase Capacitance NOTE CAUTION The effect of the mutual phase capacitances can play an important role in the back EMF sensing Usually the mutu
157. werks DC Direct Current dc bus part of power converter with direct current DC motor Direct Current motor if not mentioned differently it means the motor with brushes DT see Dead Time DT Dead Time DT short time that must be inserted between the turning off of one transistor in the inverter half bridge and turning on of the complementary transistor due to the limited switching speed of the transistors duty cycle A ratio of the amount of time the signal is on versus the time it is off Duty cycle is usually represented by a percentage ECLOVACBLDC 3 ph AC BLDC Low Voltage Power Stage ECMTRLOVBLDC 3 ph BLDC Low Voltage Motor Brake SM40N SG40N Designer Reference Manual MOTOROLA Glossary 163 For More Information On This Product Go to www freescale com Freescale Semiconductor Inc ECMTREVAL Evaluation Motor Board Kit supplied in kit with trapezoidal BLDC 1823810 ECOPTHIVACBLDC 3 ph AC BLDC High Voltage Power Stage Optoisolation Board ECMTRHIVBLDC 3 ph BLDC High Voltage Motor Brake SM40V SG40N ECOPTINL Optoisolation between host computer and MCU board evaluation or customer target cards optoisolation board ECOPT Optoisolation between power stage and processor evaluation or controller cards in line optoisolator ECCTR908MR32 Motor Control board for HC908MR32 IDE Integrated Developement Environment interrupt A temporary br
158. windings distributed in the slots has technically higher mutual inductances than other types Therefore this effect is more significant On the other hand the BLDC motor with windings wounded on separate poles shows minor presence of the effect of mutual inductance However noticeable this effect it does not degrade the back EMF zero crossing detection because it is cancelled at the zero crossing point Simple additional filtering helps to reduce ripples further DRMO28 Rev 0 32 BLDC Motor Control MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc BLDC Motor Control Brushless DC Motor Control Theory Tek Single Seq 2 50MS s T Figure 3 8 Detail of Mutual Inductance Effect 3 2 4 4 Effect of Mutual Phase Capacitance The negative effect of mutual inductance is not the only one to disturb the back EMF sensing So far the mutual capacitance of the motor phase windings was neglected in the motor model since it affects neither the phase currents nor the generated torque Usually the mutual capacitance is very small Its influence is only significant during PWM switching when the system experiences very high du dt The effect of the mutual capacitance can be studied using the model shown in Figure 3 9 DRMO028 Rev 0 Designer Reference Manual MOTOROLA BLDC Motor Control 33 For More Information On This Product Go to www freescale com
159. within the board s thermal limits Input connections are made via 40 pin ribbon cable connector J1 Power connections to the motor are made on output connector J2 Phase A phase B and phase C are labeled on the board Power requirements are met with a single external 12 Vdc 4 amp power supply Two connectors labeled J3 and J4 are provided for the 12 volt power supply J3 and J4 are located on the front edge of the board Power is supplied to one or the other but not both DRMO28 Rev 0 70 Hardware Design MOTOROLA For More Information On This Product Go to www freescale com Freescale Semiconductor Inc 4 5 1 1 Electrical Characteristics of the EVM Motor Board Hardware Design Low Voltage Evaluation Motor Hardware Set Components The electrical characteristics in Table 4 4 apply to operation at 25 C and a 12 Vdc power supply voltage Table 4 4 Electrical Characteristics of the EVM Motor Board Characteristic Symbol Min Typ Max Units Power Supply Voltage Vdc 10 12 16 V Quiescent Current lec 50 mA Min Logic 1 Input Voltage Vin 2 4 V Max Logic 0 Input Voltage Vi 0 8 V Input Resistance Rin 10 Analog Output Range Vout 0 3 3 V Bus Current Sense Voltage ISense 412 mV A Bus Voltage Sense Voltage VBus 206 mV V Power MOSFET On Resistance Rps on 32 40 MQ RMS Output Current 6 Total Power Dissipation Pais
160. www freescale com Freescale Semiconductor Inc BLDC Motor Control Table 3 1 PC Master Software Communication Commands Comman Data Demo Respon Response Command d Byte s Descriptio Suitcase Action Code s Byte n Set manual 02 None Setting of manual 00 OK mode mode 55 Failed 3 4 1 3 PC Master Software BLDC Control MCU Software API Communication Variables The application interface data variables used for the exchange between the BLDC control MCU software and PC master software are shown in Table 3 2 These variables are used for status sensing and control PC master software accesses these bytes directly from their physical memory addresses Table 3 2 PC Master Software API Variables y Representing 10 2 Name Type Description Sys3 Sys3_Def 8flags System variable 3 Motor_Ctrl Motor_Ctrl_Def 8flags Motor control variable Motor_Status uer 8flags Motor status variable Failure Failure_Def 8flags Failure variable Speed input variable used for Sp Input U8 lt 0 255 gt required speed calculation Speed_Range_Max_RP U16 lt 0 65535 gt Speed range maximum M rpm Speed Max RPM U16 7 posa Maximal speed limit Speed Min RPM U16 lt 0 Minimal speed limit rpm Commut_Rev U8 lt 0 255 gt Commutations per motor revolution lt Curr_Range_Max_c Curr S8 dc bus current Curr Range M

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