Motor Control Application Tuning (MCAT) Tool for 3
Contents
1. Freescale Semiconductor Application Note Document Number AN4642 Rev 1 01 2013 Motor Control Application Tuning MCAT Tool for 3 Phase PMSM by Marek Stulrajter Pavel Sustek 1 Introduction This application note describes a Freescale motor control tuning solution known as Motor Control Application Tuning MCAT tool MCAT is a graphical tool dedicated to motor control developers and the operators of modern electrical drives The main feature of proposed approach is automatic calculation and real time tuning of selected control structure parameters Connecting and tuning new electric drive setup becomes easier because the MCAT tool offers a possibility to split the control structure and consequently to control the motor at various levels of cascade control structure 2 Motivation An electric drive is known as a set of several subsystems such as electric motor with load controlled supply source control unit and wide range of sensors which provide a conversion of electric energy to a specific mechanical movement Performing the mechanical movement according to certain specifications requires a suitable control strategy of the electric motor Based on the motor type and the application requirements there are several dedicated control methods In general the control techniques are very complex and require knowing of controlled system parameters and control structure parameters This is a matter of experience in the motor control2. Integrator Constants Integrator gain lo 103125 Integrator scale 0 ace arr ero Seco Figure 14 POSPE sensor tab Expert mode Table 6 shows the list of the POSPE Sensors tab inputs with their physical units brief description the impacted algorithms and accessibility status in basic mode Table 6 Inputs of the POSPE Sensors tab Parameter Name Description Use in Constant Basic mode calculation TEE Encoder pulses Pulses of an encoder ATO PI controller Resolver Pole pairs of resolver ATO PI controller YES Sample Time sec Observer sampling time ATO PI controller NO FO Hz Observer bandwidth ATO PI controller NO amp Observer attenuation ATO PI controller NO Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 22 Freescale Semiconductor Inc E FT MCAT tool for 3 phase PMSM 6 5 1 POSPE sensors setting variability The PI controller within an ATO algorithm can be implemented by both parallel and recurrent way The MCAT tool supports both types of PI controllers as well as respects the variability of data type representation The available setting modes supported by the POSPE sensors tab can be seen in Table 7 Table 7 Summary of POSPE sensors setting modes Position and Speed Sensor module Applicable changes PI controllers Parallel Recurrent form Data type representation FIX FLOAT arithmetic NOTE All settings shown inTab
3. Speed PI Controller Limits Upper limit 5 TA Lower limit fA MCAT tool for 3 phase PMSM Speed Control Loop Speed PI Controller Constants Kp gain 0 621138 Kp scale 5 Ki gain 0 718102 Ki scale 1 Speed PI Controller Limits Scaled Upper Limit 0 625 Lower Limit 0 625 Speed Ramp Scaled Increments Scaled Inc Up 0 000606 Inc Down 0 000606 Sore ar See Sore Figure 11 Speed Loop tab Expert mode The Table 4 shows the list of the speed loop input parameters with their physical units brief description the impacted algorithms and accessibility status in basic mode Table 4 Input of the Speed Loop tab Parameter Name Description Use in constant Basic mode calculation accessibility Sample time sec CL sampling time Current PI controller Zero compensator FO Hz Current loop bandwidth Current PI controller NO Zero compensator amp Current loop Current PI controller NO attenuation Zero compensator Inc Up rpm sec Speed increasing with Ramp function NO the increment Inc Down rpm sec Speed decreasing with Ramp function NO the increment Filter points points Moving Average Filter NO Samples Table continues on the next page Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 17 MCAT tool for 3 phase PMSM Table 4 Input of the Speed Loop tab continued Parameter Name Description
4. 2013 24 Freescale Semiconductor Inc eee MCAT tool for 3 phase PMSM 6 6 Sensorless tab As it has been mentioned the most important signals in the PMSM FOC control scheme are speed and position feedbacks They can be acquired from either physical speed sensors or some advanced observer algorithms The Sensorless SLS tab deals with a Back Emf BEMF observer as a sensorless algorithm for the speed and position signals estimation Similar to previous tabs the SLS tab is also divided into two parts The first part represents an input data field with required sensorless parameters and parameters for open loop start up The second one is an output data field displaying the calculated parameters of BEMF observer tracking observer TO and open loop start up Application tuning modes available in Sensorless tab Basic highly recommended for users who are not enough experienced in motor control theory Only open loop start up parameters are required as an input in this mode The BEMF observer and tracking observer input parameters are estimated from the motor and application parameters automatically by MCAT tool engine The cells requiring these parameters are shadowed with the status read only as in Figure 16 Expert all input parameter cells of the SLS tab are accessible and freely editable by an user as in Figure 17 However their setting requires a certain level of expertise in motor control theory BEMF Observer DQ Po
5. 6 8 2 Voltage FOC control If the direction of the rotor spinning is according to the user demand and the measured estimated position gives also correct direction the Voltage FOC control can be chosen There are two reference variables available for motor controlling as in Figure 22 Required voltage in d axis Ug req is actually not enabled in basic tuning mode The q component of the voltage Ug req represents a torque component and by its application the motor will run Once the motor runs few tests should be provided in order to verify the conditions needed for successful torque and consequently speed control If positive Ug eq voltage is applied to the motor rotor should rotate to the positive direction and vice versa Consequently the currents have to be checked The correct phases order and polarity of the currents have to be checked Ua req Ua re sensor Figure 22 Voltage FOC control mode If it is done a control loop can be then closed with the current feedback signals by toggling the Current FOC Control 6 8 3 Current FOC control Current control or also called torque control requires rotor position feedback as well as the currents transformed into the dq synchronous frame There are two reference variables available for motor controlling as in Figure 23 Required current in d axis Iq req is actually not enabled in basic tuning mode and is kept at zero by default The q component of the current Ig req represents a
6. 65 AnNRWNeE Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 35 How to Reach Us Home Page www freescale com Web Support http www freescale com support USA Europe or Locations Not Listed Freescale Semiconductor Technical Information Center EL516 2100 East Elliot Road Tempe Arizona 85284 1 800 521 6274 or 1 480 768 2130 www freescale com support Europe Middle East and Africa Freescale Halbleiter Deutschland GmbH Technical Information Center Schatzbogen 7 81829 Muenchen Germany 44 1296 380 456 English 46 8 52200080 English 49 89 92103 559 German 33 1 69 35 48 48 French www freescale com support Japan Freescale Semiconductor Japan Ltd Headquarters ARCO Tower 15F 1 8 1 Shimo Meguro Meguro ku Tokyo 153 0064 Japan 0120 191014 or 81 3 5437 9125 support japan freescale com Asia Pacific Freescale Semiconductor China Ltd Exchange Building 23F No 118 Jianguo Road Chaoyang District Beijing 100022 China 86 10 5879 8000 support asia freescale com Document Number AN4642 Rev 1 01 2013 Information in this document is provided solely to enable system and software implementers to use Freescale Semiconductors 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
7. Freescale Semiconductor reserves the right to make changes without further notice to any products herein Freescale Semiconductor makes no warranty representation or guarantee regarding the suitability of its products for any particular purpose nor does Freescale Semiconductor assume any liability arising out of the application or use of any product or circuit and specifically disclaims any liability including without limitation consequential or incidental damages Typical parameters that may be provided in Freescale Semiconductor 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 Freescale Semiconductor does not convey any license under its patent rights nor the rights of others Freescale Semiconductor products are not designed intended or authorized for use as components in systems intended for surgical implant into the body or other applications intended to support or sustain life or for any other application in which failure of the Freescale Semiconductor product could create a situation where personal injury or death may occur Should Buyer purchase or use Freescale Semiconductor products for any such unintended or unauthorized application Buyer shall indemnify Freescale Semiconductor and its officers employees subsidiaries affiliates and dist
8. Hz Current loop bandwidth Current PI controller NO Zero compensator amp Current loop Current PI controller NO attenuation Zero compensator Output limit Limit of the current PI NO controllers 6 3 1 Current Loop Setting Variability Two types of PI controllers and optional zero cancellation blocks Figure 2 lead to several variations of current control loop structure Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 12 Freescale Semiconductor Inc FEER MCAT tool for 3 phase PMSM The MCAT tool covers both options it means it supports both types of PI controllers and offers an opportunity to use the optional zero cancellation blocks Moreover including the variability of data type representation there are several modes available that are required to be supported by the current loop tab see Table 3 Table 3 Summary of Current Loop setting modes The control loop available mode Applicable changes PI controllers Parallel Recurrent form Zero cancellation blocks Allowed Non allowed Data type representation FIX FLOAT arithmetic NOTE All settings shown in Table 3 will be predefined by Freescale developer according to the MC reference application 6 3 2 Current loop parameters calculation The parameters of the PI controllers in current loop are calculated by exploiting the pole placement PP method Pole placement method is an a
9. It is a mandatory tab due to its high level of dependency with other tabs To ensure proper MCAT tool functionality and control parameter calculation accuracy an attention must be paid when entering the input application parameters into required cells An impact of each required input is shown in Table 1 Number of input parameters that need to be filled depends on the selected application tuning mode The application tuning mode can be changed on the right side of motor selector bar and offers two options basic and expert mode Application tuning modes available in Parameters tab are as follows Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 6 Freescale Semiconductor Inc MCAT tool for 3 phase PMSM Basic highly recommended for users who are not enough experienced in motor control theory The number of required input parameters is reduced according to the Table 1 The mandatory cells are with white background while the rest of input parameters are calculated automatically by MCAT tool engine These parameters are read only and shadowed see Figure 5 Expert all inputs parameters are accessible and freely editable by a user However their setting requires a certain level of expertise in motor control theory see Figure 6 roactn a precios eerie Input Application Parameters Motor Parameters Application Scales a SS ee pp 36 UDCBtrip 288 M Rs 0 288 10 U
10. Use in constant Basic mode calculation accessibility Upper Limit Required current upper limit Lower limit A Required current lower NO limit 6 4 1 Speed Loop Setting Variability Two types of speed PI controller and optional blocks as zero cancellation block or ramp function Figure 2 lead to the several variations of speed control loop structure The MCAT tool covers all above mentioned options it means it supports both types of PI controllers and offers an opportunity to use different approach in speed feed forward path as the optional zero cancellation blocks or ramp function Moreover including the variability of data type representation there are available several modes that are required to be supported by the speed loop tab see Table 5 Table 5 Summary of Speed Loop setting modes The control loop available mode Applicable changes PI controllers Parallel Recurrent form Zero cancellation blocks Allowed Non allowed Ramp function Allowed Non allowed Ramp function FIX FLOAT arithmetic NOTE All settings shown in Table 5 will be predefined by Freescale developer according to the MC reference application 6 4 2 Speed loop parameters calculation Again the pole placement approach is used for parameters calculation of all speed loop control elements A simplified closed speed control loop shown in Figure 12 is used for deriving the parameters of all blocks of speed control
11. change signalization By pressing the Store Data button all new values from modified cells will be saved into the file After successful data saving the background of the cells becomes white and the button gets disabled The editing fields accept only numeric characters The parameter values are fully under user responsibility and no additional checking is applied to those items The typical range of the parameter value appears when the mouse pointer is in a parameter name focus 6 4 Speed Loop Tab The Speed Loop SL is a tab designed for tuning the speed control loop The speed control loop is an outer loop in the cascade control structure of vector controlled PMSM Speed loop consists of a PI controller and optional blocks like zero cancellation or ramp function Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 15 LT MCAT tool for 3 phase PMSM The SL tab is logically divided into two parts The first part represents input data fields with required control loop parameters needed for PI controller parameter calculation The second one is an output data field which displays the calculated parameters of the speed controller The PI controller constants are calculated from the motor parameters application scales and speed loop parameters Application tuning modes available in Speed Loop tab are as follows e Basic highly recommended for users which are not enough experie
12. for users who are not enough experienced in motor control theory Only sensor parameters are required as an input in this mode Position observer input parameters of the PS tab are estimated from the motor and application parameters automatically by MCAT tool engine The cells requiring these parameters are shadowed with the status read only as shown in Figure 13 Expert all input parameter cells of the PS tab are accessible and freely editable by a user as shown in Figure 14 However their setting requires a certain level of expertise in motor control theory Position amp Speed Sensors Module Position Sensor Position Observer Constants Encoder 1024 pulses Kp gain 0 713998 cal Position Observer SEES 3 Ki gain Sampletime 0 000625 sec 0 841159 Ki scale FO 150 Hz 0 1 H Integrator Constants aen Fre 0 103125 Data Type Frac32 integrator scale 5 PI controller type Parallel ace o a aa Figure 13 POSPE sensor tab Basic mode Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 21 MCAT tool for 3 phase PMSM Introduction Parameters Current Loop Speed Position amp Speed Sensors Module Position Sensor Encoder 1024 pulses Position Observer Sample time 0 000625 sec FO 150 Hg i mz Data Type Frac32 PI controller type Parallel Position Observer Constants Kp gain 0 713 Kp scale 3 Ki gain 0 841159 Ki scale 0
13. is the simplest type of electric drives control strategy The motor is supplied with the set of voltages given by the following expression Uibe U nsin 0 a Equation 31 Oe Z Nreq at Equation 32 The ratio between the magnitude of the voltage and the frequency frequency information is hidden in the Nreq has to be kept at the nominal ratio Therefore attention must be paid during entering required voltage and speed in expert tuning mode The ratio will be automatically kept constant in basic tuning mode and user does not have to take care about that The only required input will be required speed As can be seen from the Figure 21 there is no feedback in the control structure hence the name open loop control Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 32 Freescale Semiconductor Inc MCAT tool for 3 phase PMSM Um Uq req N required sensor Integrator Figure 21 Scalar control mode In fact it is not very common to use scalar control for PMSM motors Such control approach can be used just for initial application tuning Since there are no any feedbacks it is the easiest way to get the motor run just hooked with new inverter Once the motor rotates sensor estimator signals can be evaluated and aligned with the direction of rotation and so on If it is done the control loop can be closed with the rotor position signal by toggling Voltage FOC Control method
14. output e k is the controller input error signal CC1 and CC2 are controller coefficients calculated using Trapezoidal method Ts CQ Kp 1 Kr ry Equation 12 Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 14 Freescale Semiconductor Inc Ey MCAT tool for 3 phase PMSM Ts CC p Kp 7 Ky ry Equation 13 The zero cancellation transfer function Equation 4 on page 14 can be also transformed into Z domain using Backward Euler method Then the discrete implementation is therefore given by K _ Ari s a PI Yay Kp IKI its Kp Kp ITS Yk Equation 14 It is clear that Equation 14 on page 15 is a simplified form of 1 order Butterworth LP filter in IIR implementation So the zero cancellation block physically behaves as a low pass filter smoothing the input command It therefore allows increasing of the loop gain achieving higher bandwidth In depends on the PI controller implementation the controller constants Equation 9 on page 14 Equation 10 on page 14 or Equation 12 on page 14 Equation 13 on page 15 are used in case of floating point data representation The discrete implementation of PI controllers in the fixed point arithmetic platform requires the scaling approach to keep all signals in the range lt 1 1 Detailed description of proper PI controller s parameters scaling is in 3 4 6 3 3 Parameter modification All parameter cells are filled automatically with pre
15. theory which can cause difficulties to motor control 2013 Freescale Semiconductor Inc AHA ADA un A W N Contents TPO CGT ON s eanan Ee elire i A E Ol Wate Conceptes eiiiai Pey Peete cice i Target Applications riarann eae MCAT tool for 3 phase PMSM Gu GuGu sseseereerreerreree RESTER ES iela sense a A Y w gt freescale Software Concept developers or users To avoid these problems and make the tuning of the motor control applications easier Freescale has developed software solution to control and tune the electrical drives from a graphical environment running on a host PC The MCAT tool runs under FreeMASTER online monitor which allows the real time tuning of the motor control application Respecting the parameters of the controlled drive the correct values of control structure parameters are calculated which can be directly updated to the application or stored in an application static configuration file The electrical subsystems are modeled using physical laws and the parameters estimation algorithms are based on Pole placement method The given solution is a graphical user friendly tool that allows tuning of the application within minutes and will save the user much of the work 3 Software Concept The MCAT tool is a user friendly graphical plug in tool for Freescale s FreeMASTER dedicated to debugging the motor control application The environment of MCAT tool is based on HTML language whereas the
16. torque component and by its application the motor will run By changing the polarity of the current Ig eq the motor will change the direction of the rotation Supposing the Position and Speed evaluation algorithms are tuned correctly the current PI controllers can be tuned using Current Loop tab Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 33 MCAT tool for 3 phase PMSM la_req Ua req PI controller re UB req iara PI controller la real lb real Ile real Figure 23 Current torque control mode If the motor runs correctly and the Position Speed evaluation algorithm provides correct information about the speed the current control loop can be then closed with an outer speed loop by toggling the Speed FOC Control 6 8 4 Speed FOC control Speed control loop requires information about the actual rotor speed This can be provided by physical sensor or sensorless algorithm la_req Pl controller Ug req PI controller re la real PI controller sensor lb real le real We real Figure 24 Speed FOC control mode Supposing the current controllers are tuned correctly the speed PI controller can be tuned using Speed Loop tab 6 8 5 Cascade control structure controlling The variables are entered to the white boxes of the selected control method T
17. 01 2013 4 Freescale Semiconductor Inc MCAT tool for 3 phase PMSM Motor Control Application Tuning tool Number of motors One motor Two motors Type of motor Control strategy Cascade structure Open Loop Voltage FOC Control Current FOC Control Speed FOC Control Control Structure Figure 3 The application cases tree diagram 6 MCAT tool for 3 phase PMSM The MCAT tool is a graphical tool with friendly environment and intuitive control As can be seen in Figure 4 the tool consists of motor selector bar tab menu and the workspace The proposed approach supports up to three PMSM motors while each motor has its own tab menu and workspace The MCAT tool represents a modular concept that consists of several sub modules Each sub module represents one tab in the tab menu The arrangement of the sub modules is flexible according to the needs of embedded application Several tab menu combinations can be created based on the type of application for instance sensorless applications do not need any POSPE Sensors tab torque control applications do not need any Speed Loop tab and so on Based on this the initial setting of the MCAT tool will be provided by Freescale team developing the motor control reference designs Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 5 MCAT tool for 3 phase PMSM 2 frees
18. 138 Data Type Frac32 Zeef pee ue Figure 17 Sensorless tab Expert mode The Table 8 shows the list of the Sensorless tab inputs with their physical units brief description the impacted algorithms and accessibility status in basic mode Table 8 Inputs of the Sensorless tab Parameter Name Description Use in Constant Basic mode calculation accessibility Hz BEMF loop natural BEMF observer frequency E BEMF loop attenuation BEMF observer NO FO Hz TO loop natural Tracking observer NO frequency amp TO loop attenuation Tracking observer NO Start up ramp rpm sec The slope of risen Open loop start up YES current Start up current A Current limit for start up Open loop start up YES process Merging speed rpm Switch open to closed Open loop start up NO loop at given speed Merging speed How fast switch open Open loop start up NO to closed loop position Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 26 Freescale Semiconductor Inc C MCAT tool for 3 phase PMSM 6 6 1 Sensorless setting variability The only variability within the Sensorless tab is given by a different data type representation as in Table 9 Table 9 Summary of Sensorless setting modes Position and Speed Sensor module Applicable changes Data type representation FIX32 FIX16 NOTE All settings shown in Table 9 will be predefined by
19. DCBunder 14 4 M Ld 0 000468 TH U DCB over 288 M 0 000618 fH Nmax Ej ke 0 0577 M secirad Umax 208 M J 0 000025 kg m2 Emax 5982 M Iph nom 5A k 004711 Nma Uph nom 48 M r Alignment N required max 3000 rpm Align current 050 Al Hardware Scales Align duration 0 00132 sec I max os upcBmax 36 M za aa Figure 5 Parameters tab Basic mode Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 7 MCAT tool for 3 phase PMSM Introduction Input Application Parameters Motor Parameters Application Scales pp 3 4 U DCB trip 28 8 M Rs 0 288 10 U DCB under 144 M Ld 0 000468 HI U DCB over 288 M Lq 0 000618 H N max 3300 0 rpm ke 0 0577 V secirad Umax 208 M J 0 000025 kg m2 E max 59 82 M Iph nom 5 Ay kt 0 04711 Nm A Uph nom 18 M Alignment N required max 3000 rpm Align current 0 50 Al Hardware Scales Align duration 0 00132 sec I max 8 TAJ Update FRM upcBmax 36 M Bae Sa aa Figure 6 Parameters tab Expert mode The Table shows the list of the MCAT tool input parameters with their physical units brief description the impacted algorithms and accessibility status in basic mode Table 1 Inputs of the Parameter tab Parameter Name Description Use in constant Basic mode calculation accessibility Yes pp Motor pole pairs Spe
20. Freescale developer according to the MC reference application 6 6 2 Sensorless algorithm parameter calculation Detailed overview describing the coefficient calculation of Back EMF observer and Tracking observer is shown in 4 6 6 3 Parameter modification All parameter cells are filled automatically with predefined data downloaded from an external file The parameter cells are freely accessible for editing in accordance to the selected tuning mode as it is shown in Table 8 There are four user buttons on the page with the following functionality e Calculate the button is disabled by default The button becomes enabled as soon as one of the input sensor or observer parameters is changed The background of the cell is changed from white to pink color for the purpose of change signalization By pressing the Calculate button PI controller parameters and integral coefficient are recalculated according to the Sensorless algorithm parameter calculation Update FRM the button is enabled by default By pressing the button the application algorithms on the embedded side are updated with the ones displayed in output field data Reload Data the button is disabled by default The button becomes enabled as soon as one of the input BEMF TO or open loop start up parameter is changed The background of the cell is changed from white to pink color for the purpose of changes signalization By pressing the Reload Data button the all modified cells wil
21. IT Equation 4 The current loop transfer function with the zero cancellation block in feed forward is then Ge 5 Gris 2 roe E Equation 5 t ohon Having the closed loop with canceled zero Equation 5 on page 14 the PI controller can be designed by comparing the closed loop characteristic polynomial with that of a standard second order system as Kp rtR Ki I 2 7 b 82 20 s cof Equation 6 where Wg is the natural frequency of the closed loop system loop bandwidth and is the loop attenuation The proportional and integral gains of the PI controller can be therefore calculated from Equation 6 on page 14 as Kp 2 amp o L R Equation 7 K 1 L g Equation 8 Equation 7 on page 14 Equation 8 on page 14 describe a PI controller design in continuous time domain Considering the discrete domain the expressions Equation 7 on page 14 Equation 8 on page 14 will change as follows Kp 1 2z Kr ds Equation 9 K iz K As Equation 10 where Ts is sampling period of the current loop The form of PI controller Equation 1 on page 13 implementation which allows the user to define the proportional and integration components independently without interaction is called parallel PI controller Another type of PI controller implementation is recurrent form that can be reached by transforming Equation on page 13 into a discrete domain as follows Equation 11 where u k is the controller
22. ameter calculation Update FRM the button is enabled by default By pressing the button the application PI controllers on the embedded side are updated with those ones displayed in output field data e Reload Data the button is disabled by default The button becomes enabled as soon as one of the input sensor or observer parameters is changed The background of the cell is changed from white to pink color for the purpose of changes signalization By pressing the Reload Data button the all modified cells will be rewritten with original values taken from the file After successful data reload the background of the cells becomes again white and the button gets disabled e Store Data the button is disabled by default The button becomes enabled as soon as one of the input sensor or observer parameters is changed The background of the cell is changed from white to pink color for the purpose of changes signalization By pressing the Store Data button all new values from modified cells will be saved into the file After successful data saving the background of the cells becomes white and the button gets disabled The editing fields accept only numeric characters The parameter values are fully under a user responsibility and no additional checking is applied to those items The typical range of the parameter value appears when the mouse pointer is in a parameter name focus Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01
23. ameters tdefine Q KP_GAIN define QO KP SC define Q KI G IN define Q KI SC Speed Loop Control Loop bandwidth Loop attenuation Loop sample time def ine SPEED KP GAIN def ine SPEED KP SC 20 8 3300 0 0 59 82 FRAC32 0 8 FRAC32 0 4 FRAC32 0 8 22 FRAC32 0 0625 0 0000625 sec FRAC32 0 9 FRAC32 0 832528705594 1 FRAC32 0 771567772796 5 FRAC32 0 585185373171 0 FRAC32 0 509432567936 4 FRAC32 0 62113850398 5 Figure 18 Output File tab example In other words the Output File tab shows a content of the file that can be generated by MCAT tool The coefficients that correspond to the tuned application represent the static configuration of the PMSM FOC application Static configuration file is a part of the S W package as seen in Figure 1 and it is linked with the application source code as a header file Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 29 MCAT tool for 3 phase PMSM 6 7 1 Output file generation To generate the content of the Output File tab Generate Configuration File button needs to be pressed The header file PMSM_appconfig h is generated and will be saved to the default path 6 8 Cascade tab Cascade tab deals with the control structure of the PMSM motor Assuming that the embedded application is based on the cascade control structure depicted in Figure 2 the Cascade tab
24. anged in series represents hierarchical structure which is characteristic by a feedback hence the name closed loop system Proportional integral PI controllers are the most commonly used as feedback controllers that provide an error calculation as the difference between a measured process variable and desired reference variable The PI controller attempts to minimize the control loop error by adjusting the actuating signal in other words the controller output signal Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 3 Target Applications Optional blocks la req la req ZC T Ug req gE dq SVMF4y VSI t Zero cancellation ld real PI controller Ug req Ug req iL eI PMSM Ramp PI controller Zero cancellation we PI controller W real AC Zero cancellation sensor Io real Position Speed evaluation Figure 2 Cascade structure speed FOC of PMSM There are two types of PI controllers mostly used in the control algorithms We distinguish between parallel and recurrent form of the PI controller Based on the form the PI controller algorithm involves two separate constant parameters the proportional component Kp and integral component Ky for parallel form or their equivalents CC1 and CC2 for recurrent form Setting of these constants depends on the required control loop be
25. cale Motor Control Application Tuning Tool Motor 1 PMSM ed Motor 2 PMSM e Motor 3 PMSM d sober s re cascate ee MCAT tool tab MENY B enn Application Description MCAT tool workspace Application concept A position and speed estimation method without position transducer is applied for horizontal axis washing machines with Permanent Magnet Synchronous Motor PMSM By integrating methods i e using a speed reference for zero speed startup and low speed acceleration and back EMF for mid high speed operation the rotor position can be estimated and controlled over the full speed range In order to achieve correct operation from zero speed the two techniques are combined with a crossover function based on the speed reference Freescale Inc 2012 Designed by Motor Control Teams Roznov pod Radhostem Figure 4 MCAT tool environment Predefined MCAT tool will be a part of reference software for dedicated MCU Since the tuning tool cannot be used as a standalone it will be included in the FreeMASTER project by default The MCAT tool workspace is unique for each tab and detailed overview of each available tab is provided in the following chapters 6 1 Introduction tab An Introduction tab can be considered as a voluntary tab It provides a room for describing or introducing the targeted MC application Figure 4 6 2 Parameters tab A Parameters tab is dedicated for entering the input application parameters
26. defined data downloaded from an external file The parameter cells are freely accessible for editing according to the selected tuning mode as shown in Table 2 There are four user buttons on the page with the following functionality e Calculate the button is disabled by default The button becomes enabled as soon as one of the input Loop Parameters is changed The background of the cell is changed from white to pink color for the purpose of change signalization By pressing the Calculate button all PI controller parameters are recalculated according to the Current loop parameters calculation Update FRM the button is enabled by default By pressing the button the application PI controller parameters on the embedded side are updated with the ones displayed in output field data Reload Data the button is disabled by default The button becomes enabled as soon as one of the input Loop Parameters is changed The background of the cell is changed from white to pink color for the purpose of change signalization By pressing the Reload Data button all the modified cells will be rewritten with original values taken from the file After successful data reload the background of the cells becomes again white and the button gets disabled Store Data the button is disabled by default The button becomes enabled as soon as one of the input Loop Parameters is changed The background of the cell is changed from white to pink color for the purpose of
27. ed and Position module Rs Q Resistance of one Current PI controller Yes motor phase BEMF Observer Ld H Direct Inductance of Current PI controller Yes one motor phase BEMF Observer Lq H Quadrature Inductance Current PI controller Yes of one motor phase BEMF Observer ke V sec rad Back EMF constant BEMF Observers Yes J Kg m Drive Inertia Speed PI controller Yes Iph nom A Nominal phase current Current scale Yes calculation Uph nom V Nominal phase voltage Voltage scale Yes calculation Table continues on the next page Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 8 Freescale Semiconductor Inc MCAT tool for 3 phase PMSM Table 1 Inputs of the Parameter tab continued Parameter Name Description Use in constant Basic mode calculation accessibility N required max rpm Maximal required speed Speed scale calculation in the application It is not a speed scale Imax A HW current sensing Current PI controller No scale BEMF Observer Speed Controller U DCB max V HW DC Bus voltage Current PI controller No scale BEMF Observer Speed Controller U DCB trip V Trigger value that Fault protection No switches an external DC Bus braking resistor on U DCB under V Voltage value that Fault protection No generates DC Bus UNDER VOLTAGE fault U DCB over V Voltage value that Fault protection No generates DC B
28. from an external file The parameter cells are freely accessible for editing according to the selected tuning mode as shown in Table 4 There are four user buttons on the page with the following functionality e Calculate the button is disabled by default The button becomes enabled as soon as one of the input Loop Parameters is changed The background of the cell is changed from white to pink color for the purpose of changes signalization By pressing the Calculate button all PI controller parameters are recalculated according to the Speed loop parameters calculation Update FRM the button is enabled by default By pressing the button the application PI controllers on the embedded side are updated with the ones displayed in output field data Reload Data the button is disabled by default The button becomes enabled as soon as one of the input Loop Parameters is changed The background of the cell is changed from white to pink color for the purpose of change signalization By pressing the Reload Data button all the modified cells will be rewritten with original values taken from the file After successful data reload the background of the cells becomes white again and the button gets disabled Store Data the button is disabled by default The button becomes enabled as soon as one of the input Loop Parameters is changed The background of the cell is changed from white to pink color for the purpose of change signalization By pressing
29. g allows MCAT tool to utilize the runtime debugging features in order to tune the embedded application Once the application is tuned properly MCAT tool offers a possibility to store all constants in a file and export them as static configuration see Figure 1 The application static configuration represents a part of Freescale reference S W package and will be added into the reference S W as a header file NOTE The MCAT tool can be linked only with FreeMASTER version 1 3 16 or higher Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 2 Freescale Semiconductor Inc Key Features 4 Key Features The given approach is designed to tune the motor control applications in other words it provides the support for embedded applications The application meets the following performance specifications Supports up to three motor applications Keeping an independent access to each motor e Supports embedded applications that are compliant with MCAT tool standards e Utilizes a Pole Placement method for control parameters estimation Real time tuning and updating of control parameters Offers a preview of the static configuration of tuned parameters Generates an output file with static configuration of tuned parameters e MCU independent It supports platforms such as Kinetis MPC and DSC e Applicable for Freescale microcontrollers only e Plug in tool for FreeMASTER not available as a stand alone tool Offer
30. hase PMSM gies are AA eae se cans Application Control Structure rpm Speed FOC Control lt y c Sensor type encoder M State Control p Cascade Control Structure Composition ae SE ES ON Scalar Control lt lt Um lo M ENABLED view masu gt 7 Speed req 500 rpm Voltage FOC M S OFF view a Uq _req M Application State Current FOC 7 c Id_req A RUN a view _ Ia_req IA Update FRM Figure 19 Cascade tab Basic mode Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 31 MCAT tool for 3 phase PMSM aos ES TELE ee cans ee Application Control Structure State Control Cascade Control Structure Composition ON Scalar Control c Um M RR view konnan Speed req rpm Voltage FOC ao a OFF view Uq req M Application State a c Id_req IA RUN La view n Iq_req A Update FRM 3 Speed FOC Control lt 6000 view Spent rag ta Position amp Speed encoder IE F EAGLES Sensortype encoder Figure 20 Cascade tab Expert mode Despite the tool deals with the common cascade control structure getting a full support of Cascade tab requires software switches in the embedded FOC implementation Such modification will be an integral part of Freescale reference source code Then the toggling control mode can be used 6 8 1 Scalar Control It
31. havior such as the loop bandwidth or attenuation As seen in Figure 2 the control structure can be extended by additional optional blocks placed in the feed forward path of the control loop They are called Zero Cancellation blocks and play an important role in term of compensation of a closed loop zero introduced by a PI controller Ramp block modifies the edges of speed step change command and introduces a slope behavior to the reference speed request Proposed MCAT tool helps the user to properly calculate the constants of the control structure with respecting the overall system parameters as well as the parameters of the control 5 2 Application cases tree The MCAT tool was designed to tune and control the applications employing up to three motors Such a strategy covers wide range of the multiple motor applications with different conditions Cascade control approach allows the PMSM motor to be controlled by following the FOC principles Additional feature of the MCAT tool is an open loop scalar control of PMSM motor The last but definitely not least feature of the MCAT tool is position speed feedback option In recent times there are plenty of various sensors such as resolver or encoder demanded Very popular and often required is also sensorless design of a PMSM control All main MCAT tool features reflecting the possible application cases are summarized in Figure 3 Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1
32. he cells disabled due to the basic tuning mode are shadowed Selected method is marked with a red colored button with a title ENABLED To change the control structure safety the application must be OFF Toggling the control strategy the related red colored button has to be pressed Each change of reference value has to be confirmed by a button Update FRM If there is more than one source of the position speed information the proper sensor type can be selected from the list Sensor type Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 34 Freescale Semiconductor Inc References 6 9 Application control tab The last tab available from the menu is App Control tab It is a voluntary tab that offers a possibility to display an optional application control HTML based page This option will be fully supported by a Freescale developer and will depend on the application type as well as the target MCU As an example of possible application control pages can be found 5 6 7 References FreeMASTER user s manual freescale com FreeMASTER AN4518 Dual 3 Phase PMSM Development Kit with MPC5643L freescale com AutoMCDevKits Automotive Math and Motor Control Library Set fixed point arithmetic freescale com AutoMCLib Embedded Software and Motor Control Libraries AN4561 3 Phase PMSM Motor Control Kit with the MPC5604P page 24 DRM110 Sensorless PMSM Control for an H axis Washing Machine Drive page 6
33. he input application parameters has changed as well a new set of application scales have to be recalculated The Calculate button provides calculation and update of application scales values Reload Data the button is disabled by default If the value in a particular field has changed the background of the cell is changed from white to pink color for the purpose of signalization the changes and the button becomes enabled By pressing the Reload Data button all modified cells will be filled with original values taken from the file After successful data reload the background of the cells becomes white and the button gets disabled e Store Data the button is disabled by default If the value in a particular field has changed the background of the cell is changed from white to pink color for the purpose of signalization the changes and the button becomes enabled By pressing the Store Data button all new values from modified cells will be saved into the file After successful data saving the background of the cells becomes white and the button gets disabled The editing fields accept only numeric characters The parameter values are fully under a user responsibility and no additional checking is applied to those items The typical range of the parameter value appears when the mouse pointer is in a parameter name focus 6 3 Current Loop tab The Current Loop CL is a tab designed for tuning of the current control loop The current control loop
34. is the most inner loop in the cascade control structure of vector controlled PMSM One of the FOC features is separate controlling of the flux d axis and torque q axis components of the current Figure 2 Due to this PMSM control structure has two current loops and each of them consists of a PI controller and an optional zero cancellation block The CL tab is logically divided into two parts The first part represents an input data field with required control loop parameters needed for PI controller parameter calculation The second one is an output data field which displays the calculated parameters of PI controllers in both d and q axis All PI controller constants are calculated from the motor parameters application scales and current loop parameters Application tuning modes available in Current Loop tab e Basic highly recommended for users who are not experienced enough in motor control theory There are no input parameters required in this mode All input parameters of the CL are estimated from the motor and application parameters automatically by MCAT tool engine The cells requiring these parameters are shadowed with the status read only Figure 7 Expert all input parameters cells of the CL are accessible and freely editable by the user as given in Figure 8 However their setting requires a certain level of expertise in motor control theory Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 10 F
35. l be rewritten with original values taken from the file After successful data reload the background of the cells becomes again white and the button gets disabled Store Data the button is disabled by default The button becomes enabled as soon as one of the input sensor or observer parameters is changed The background of the cell is changed from white to pink color for the purpose of change signalization By pressing the Store Data button all new values from modified cells will be saved into the file After successful data saving the background of the cells becomes white and the button gets disabled The editing fields accept only numeric characters The parameter values are fully under user responsibility and no additional checking is applied to those items The typical range of the parameter value appears when the mouse pointer is in a parameter name focus 6 7 Output file tab Previous tabs are mainly dedicated to tuning the motor control applications Once the application is tuned according to the requirements it might be useful to store the coefficients that correspond to the overall electrical drive For this purpose an Output File tab has been designed and it is a part of tab menu Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 27 SQ EEEEE 7E7 Hm LEL ELE MCAT tool for 3 phase PMSM The Output File OF tab serves a preview of the application coefficient
36. le 7 will be predefined by Freescale developer according to the MC reference application 6 5 2 POSPE sensors parameter calculation Angle Tracking Observer algorithm is used for the estimation of the rotor angle and the angular speed The ATO approach yields smooth and accurate estimations As in any common closed loop systems the intent is to minimize observer error The observer error is given here by subtraction of the estimated resolver rotor angle from the actual rotor angle see Figure l5 cos O sin Qest COS OQest Figure 15 Block scheme of the Angle Tracking Observer The position tracking structure according to the scheme Figure 15 can be expressed by the following transfer function Dosis Kp ATOS K ATO Gatols Bem SKP ATOSKI ATO Equation 25 The observer error corresponds to the formula of the difference of two angles sin 0 cos O s1 g cos 0 sin O s1 F sin 6 a Dest Equation 26 The ATO PI controller can be designed by comparing the closed loop characteristic polynomial Equation 25 on page 23 with that of a standard second order system and the angle tracking observer coefficients Kp aro and Ky aro can by calculated using Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 23 ne MCAT tool for 3 phase PMSM Kp ato z Kp_ato s 4n f i Equation 27 2 Kr atoz Kr atols Ts 2af o Ts Equation 28 where is the requi
37. loop Zero cancellation PI controller Motor Wreq Dec Inc Figure 12 Simplified speed control loop Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 18 Freescale Semiconductor Inc SSS SSS MCAT tool for 3 phase PMSM In most cases the electrical time constant of the RL circuit T is much smaller than the mechanical time constant of the motor Tmec Small Ta requires the current control loop running at higher sampling frequency hence the name fast loop On the contrary the speed loop regarding the higher time constant can run in slower control loop with lower sampling frequency Such approach gives enough time to control the current between two speed samples Based on this the behavior of the current loop can be considered as a torque gain from speed loop perspective The speed loop is closed by a PI controller which enables speed control with zero steady state error Considering a general form of closed loop with a first order plant and PI controller Kp ostK Gp As as Equation 15 Gy s 5 Equation 16 where K represents torque constant J is a moment of inertia and B is a friction Then the speed closed loop transfer function is derived in Laplace domain as follows KrK KrKp T ze KP w zo stl Gals roal Gel ds G uds KI w wreg zd 1 Gpr oS Gyls ST w TE w panir ice w Equation 17 Similar to the approach described in the current loop parameters calculati
38. might be very helpful Connecting and tuning new electric drive setup becomes easier because the MCAT tool via Cascade tab offers a possibility to split the control structure and consequently to control the motor at various levels of cascade control structure Such cascade control loops arrangement results to four optional control modes scalar control mode e voltage FOC control current FOC control e speed FOC control The Cascade tab contains ON OFF switch that can run the application a window for displaying the current application state Update FRM button that provides an update of reference variables on embedded application side and finally the window with separately distributed control buttons for each available level of control structure The functionality of each control mode will be described in the following topics Application tuning modes available in Cascade tab Basic highly recommended for users who are not enough experienced in motor control theory as in Figure 19 The inputs availability in basic mode depends on the selected control mode and will be described in the related topics Expert all input parameter cells of the Cascade tab are accessible and freely editable by an user as in Figure 20 However their setting requires a certain level of expertise in motor control theory Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 30 Freescale Semiconductor Inc MCAT tool for 3 p
39. nced in motor control theory There are no input parameters required in this mode All input parameters of the SL are estimated from the motor and application parameters automatically by MCAT tool engine The cells requiring these parameters are shadowed with the status read only as in Figure 10 Expert all input parameters cells of the SL are accessible and freely editable by an user as in Figure 11 However their setting requires a certain level of expertise in motor control theory emery iia i er sae SE som Speed Control Loop Loop Parameters Speed PI Controller Constants Sample time 0 001 sec Kp gain 621138 FO 23 Hz Kp scale t 1H Ki gain 0 71810 ale Ki scale Data Type Frac32 eo PI controller type Parallel Speed PI Controller Limits Scaled Upper Limit 0 625 Speed Ramp Lower Limit 0 625 ncup 2000 SiNSec Speed Ramp Scaled Increments Scaled Inc Down 2000 rpm sec Inc Up 0 000806 Actual Speed Filter Inc Down 0 000606 Filter points 2 points 2 Speed PI Controller Limits Upper limit 5 A Lower limit 5 Al Update FRM j Figure 10 Speed Loop tab Basic mode Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 16 Freescale Semiconductor Inc Loop Parameters Sample time 0 001 sec FO 23 HZ 128 Data Type Frac32 PI controller type Parallel Speed Ramp Inc Up 2000 rpm sec Inc Down 2000 rpm sec Actual Speed Filter Filter points 2 points
40. on Current loop parameters calculation the speed PI controller introduces a zero to the closed loop transfer function The zero can be compensated by introducing a zero cancellation block into the speed feed forward path which has the following transfer function KI Equation 18 The speed loop transfer function with the zero cancellation block in feed forward path is then reas G Gpr_ols Gu s Lre SZC red s 7 AS 1Gp als Guls EH 2 EERE NESS To Equation 19 Gals T Then the proportional and integral gains of the PI controller as well as the zero cancellation block parameters can be derived as follows i aa Kp _olz Kp_ols eu Equation 20 Ki lz K1 AJT s ETs Equation 21 where Ts is sampling period of the speed loop w is the natural frequency of the closed loop system loop bandwidth and amp is the speed loop attenuation The constants Equation 20 on page 19 Equation 21 on page 19 represent a parallel form of PI controller whereas the recurrent type of PI controller utilizes CC1 and CC2 constants Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 19 A MCAT tool for 3 phase PMSM Ts CCI o E KP o ig Ki o7 Equation 22 Ts CC w KP o Ki o7 Equation 23 The zero cancellation transfer function Equation 18 on page 19 can be also transformed into Z domain using Backward Euler method Then the discrete implementation i
41. pproach of the feedback control system theory to place the closed loop poles of a plant in pre determined locations The PP method applied to the closed loop system leads to desired controlled system behavior A simplified closed current control loop shown in Figure 9 is used for deriving the PI controller parameters calculation process Zero cancellation PI controller RL circuit Figure 9 Simplified current control loop Considering a general form of closed loop with RL model as a plant of first order and PI controller Kp js K I Gri 9 gt Equation 1 Grels Tak Equation 2 where L is the stator inductance and R is a stator resistance The closed loop transfer function is derived in Laplace domain as follows KI 1 KP I G s ireal Gp_ s Ggy s r APL At i FE et 7 lege frog 2s Ger AGr a mao KIT Ceo fe A I Equation 3 The PI controller however introduced a zero to the closed loop transfer function for command changes located at Ky Kp 1 This derivative characteristic of the loop increases the system overshoot lowering the potential closed loop bandwidth Due to this the zero of the PI controller must be compensated This can be done by introducing a zero cancellation block in the feed forward path which has the following transfer function Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 13 LEE a MCAT tool for 3 phase PMSM Ced EE K
42. red attenuation f required bandwidth in Hz and Tg is sampling time The constants Equation 27 on page 23 Equation 28 on page 24 represent a parallel form of PI controller whereas the recurrent type of PI controller utilizes CC1 and CC2 constants Ts CC ato Kp atot Ki ATT Equation 29 T CC ato Kp atot Kr ato Equation 30 The PI controller coefficients Equation 27 on page 23 Equation 28 on page 24 Equation 29 on page 24 Equation 30 on page 24 are used in case of floating point data representation The discrete fixed point arithmetic implementation of PI controllers requires the scaling approach to keep all signals in the range lt 1 1 Detailed description of proper PI controller s parameters scaling is in 3 4 6 5 3 Parameter modification All parameter cells are filled automatically with predefined data downloaded from an external file The parameter cells are freely accessible for editing in accordance to the selected tuning mode as it is shown in Table 6 There are four user buttons on the page with the following functionality Calculate the button is disabled by default The button becomes enabled as soon as one of the input sensor or observer parameters is changed The background of the cell is changed from white to pink color for the purpose of changes signalization By pressing the Calculate button PI controller parameters and integral coefficient are recalculated according to the POSPE sensors par
43. reescale Semiconductor Inc MCAT tool for 3 phase PMSM Current Control Loop r Loop Parameters _ _ M D Axis Controller r Q Axis Controller Sample Time 0 0000625 sec Kp_gain 0 832528 Kp_gain 0 585185 FO 233 Ha Ki gain o771567 Ki oain 0 509432 me Kp scale PEE Kp_scale a Ki_scale 5 Ki_scale 4 Data Type Frac32 Pl controller type Parallel Current PI Controller Limits Output limit 90 o ere T Figure 7 Current Loop tab Basic mode Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 11 MCAT tool for 3 phase PMSM Current Control Loop Loop Parameters D Axis Controller Q Axis Controller Sample Time 0 0000625 sec Kp_gain 0 832528 Kp_gain 0 585185 FO 233 Hz Ki_gain 0 771567 Ki_gain 0 509432 E I 1 Kp_scale Kp_scale Oo Ki_scale 5 Ki_scale a Data Type Frac32 PI controller type Parallel Current PI Controller Limits Output limit 90 Sr eee ee S Figure 8 Current Loop tab Expert mode The Table 2 shows the list of the current loop input parameters with their physical units brief description the impacted algorithms and accessibility status in basic mode Table 2 Inputs of the Current Loop tab Parameter Name Description Use in Constant Basic Mode Calculation Accessibility Sample Time sec CL sampling time Current PI controller Zero compensator FO
44. ributors 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 claims alleges that Freescale Semiconductor was negligent regarding the design or manufacture of the part RoHS compliant and or Pb free versions of Freescale products have the functionality and electrical characteristics as their non RoHS complaint and or non Pb free counterparts For further information see http www freescale com or contact your Freescale sales representative For information on Freescale s Environmental Products program go to http www freescale com epp Freescale and the Freescale logo are trademarks of Freescale Semiconductor Inc All other product or service names are the property of their respective owners 2013 Freescale Semiconductor Inc ey freescale W
45. s basic and expert tuning mode e Modular S W concept easily configurable 5 Target Applications In recent times there are plenty of servo drive applications employing various types of electric motors Freescale based on its experiences mainly focuses on permanent magnet types of electric drives such as Permanent Magnet Synchronous Motor PMSM and Brushless Direct Current BLDC motor Both of them are very popular in wide variety of the motor control applications due to their performance efficiency reliability easy controlling and so on Another type of motors Asynchronous Induction Motor ACIM or Switched Reluctance Motor SRM are not widely used as servo drives however they are still popular due to their absence of expensive permanent magnets The application note describes the PMSM application tuning variant as a first motor module of MCAT tool From a wide spectrum of PMSM control techniques the most common one has been chosen for the purpose of electric drives tuning by using MCAT tool The most popular and widely used control strategy for PMSM motors is Field Oriented Control FOC which is characterized by smooth rotation over the entire speed range of the motor full torque control at zero speed and fast acceleration deceleration 5 1 PMSM Field Oriented Control Field Oriented Control 2 also called vector control is based on the cascade structure with inner current loop and outer speed loop Figure 2 The control loops arr
46. s that correspond to the tuned motor control application as in Figure 18 The coefficients are thematically divided into the groups according to selected control tabs as follows Application scales Mechanical alignment Current loop parameters Speed loop parameters Position and Speed Sensors module parameters if required Sensorless BEMF DQ observer if required Cascade control structure parameters if required FreeMASTER scale variables There are no application tuning modes available for this tab Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 28 Freescale Semiconductor Inc MCAT tool for 3 phase PMSM se oe Output File mt iis AE Sensores cascade Generate Configuration File File Name PMSM_appconfig h File Source TWRK60_PMSM_SENSORLESS src Date December 4 2012 10 52 11 Description Automatically generated file for static configuration of the PMSM FOC application Application Scales a define I_MAX define U_DCB_ MAX define U_MAX define N_MAX define E_MAX define U_DCB_TRIP define U_DCB_UNDERVOLTAGE define U_DCB_OVERVOLTAGE Mechanical alignment define ALIGN_DURATION define ALIGN_CURRENT Current Loop Control Loop bandwidth Loop attenuation Loop sample time define CLOOP_LIMIT D axis parameters define D_KP_GAIN define D_KP_SC define D_KI_GAIN define D KI SC Q axis par
47. s therefore given by ace OS gp e U VI KP KI ols Mk Kp oF KT oTs Vk Equation 24 The discrete implementation of speed zero cancellation block represents a simplified form of 1st order Butterworth LP filter in IIR implementation It depends on the PI controller implementation the controller constants Equation 20 on page 19 Equation 21 on page 19 Equation 22 on page 20 Equation 23 on page 20 are used in case of floating point data representation The discrete implementation of PI controllers in the fixed point arithmetic platform requires the scaling approach to keep all signals in the range lt 1 1 Detailed description of proper PI controller s parameters scaling is in 3 4 As can be seen to get the constants of the speed loop a very sensitive parameter moment of inertia is required However there is plenty of motor control applications where this parameter is either completely unknown or rapidly changed during the operation in depends on the load torque behavior In such case the ramp function placed in the speed feed forward path can be used instead of zero cancellation block The ramp behavior of the required speed can partly suppress the impact of the inaccurate calculated PI controller parameters caused by a difference in estimated moment of inertia More details about ramp function can be found in 3 4 6 4 3 Parameter modification All parameter cells are filled automatically with predefined data downloaded
48. sition and Speed Calculation BEMF Observer Parameters BEMF Obsrv Constants TO Constants FO 150 Hz I scale 0 962962 Kp gain 0 969696 E 448 Uscale 0 334362 Kp scale Tracking Observer Parameters man FO 40 H ERE Kp gain 0 635676 Theta gain 0 66 Open Loop Start up Parameters pouce 3 esee 5 Start up ramp 1000 rpm sec sae 0 889511 OL Start up Constants Start up current 1 TAJ mince 8 Start up Inc 0 000303 Merging speed 300 rpm Start up Scaled 0 125000 Merging coeff 50 Merging N Scaled 0 090909 Merging Coeff 0 008138 Data Type Frac32 SSeS ee Ser Serene Figure 16 Sensorless tab Basic mode Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc 25 MCAT tool for 3 phase PMSM Introduction Parameters Current Loop Speed BEMF Observer DQ Position and Speed Calculation BEMF Observer Parameters BEMF Obsrv Constants TO Constants FO 150 Hz I scale 0 962962 Kp gain 0 969696 E 10 U scale 0 334362 Kp scale E Tracking Observer Parameters TES 0 901612 9r 84s 7 WI scale 0 082394 Ki scale 12 1H Kp gain 0 635676 Theta gain 0 66 Open Loop Start up Parameters Soucis 3 mee 5 Start up ramp 1000 rpm sec syan 0 889511 OL Start up Constants Start up current a A i cae 8 Start up Inc 0 000303 Merging speed 300 rpm Start up Scaled 0125000 Merging coeff 50 Merging N Scaled 0 090909 Merging Coeff 0 008
49. the Store Data button all new values from modified cells will be saved into the file After successful data saving the background of the cells becomes white and the button gets disabled The editing fields accept only numeric characters The parameter values are fully under user responsibility and no additional checking is applied to those items The typical range of the parameter value appears when the mouse pointer is in a parameter name focus Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 20 Freescale Semiconductor Inc E MCAT tool for 3 phase PMSM 6 5 POSPE sensors tab The most important signals in the PMSM FOC control scheme are speed and position feedbacks The POSPE sensors PS tab deals with the algorithm for the speed and position signals estimation An angle tracking observer ATO represents a Freescale SW solution for obtaining the actual angle and speed of the resolver and encoder sensors Similar to previous tabs the PS tab is also divided into two parts The first part represents an input data field with required sensor parameters and ATO loop parameters needed for ATO PI controller parameters calculation The second one is an output data field displaying the calculated parameters of the ATO algorithm The ATO PI controller constants are calculated from the application scales and ATO loop parameters Application tuning modes available in POSPE sensors tab e Basic highly recommended
50. tool engine is based on Jscript language The HTML and Jscript are widely used on the Internet so the design can be made with the help of the web authoring tools which are commercially available or even free on the Internet Proper displaying of the MCAT tool as an HTML code is provided by the FreeMASTER software exploiting Microsoft Internet Explorer FreeMASTER software implements an ActiveX object which is used to enable access to and control the target board application More details about FreeMASTER tool can be found in 1 An integration of MCAT tool into the development process chain is shown in Figure 1 SOFTWARE fem i mm HARDWARE I I FreeMASTER Freescale MCU RUNTIME Freescale aa 6 Freescale H W online monitor Application debugging reference control design setup PI controllers tuning Control schemes layering PI controller Ug rq nm reg lems gt L Kosky gt L kak F o Pl controller fur PI controller a mej w ap v rn ap x abc I I I I I I l I i I il I I I I I I I I I I I Development Studio Pose Freescale BUILD PROCESS N S W Package Output file Motor Control Library set Position Speed Embedded application lt valuation Motor Control Reference Design Figure 1 The software concept of MCAT tool utilization FreeMASTER as a tool for hard real time applications monitorin
51. us OVER VOLTAGE fault N max rpm Speed scale maximal Speed and position No value of electrical angular velocity BEMF Observer Tracking Observer U max V Voltage scale Current PI Controller No maximal value of FOC BEMF Observer E max V Back EMF voltage BEMF Observer No scale kt Nm A Torque constant Speed PI controller No Align current voltage A V DC value of current or Rotor alignment No voltage for rotor alignment Align duration sec Duration of rotor Rotor alignment No alignment The parameters of the controlled motor can be acquired from a motor datasheet provided by motor manufacturer or from laboratory measurement 6 2 1 Parameter modification All parameter cells are filled automatically with predefined data downloaded from an external file The input parameter cells are freely accessible for editing in accordance to the selected tuning mode as it is shown in Table 1 There are four user buttons on the page with the following functionality e Update FRM the DC voltage or current and the duration of applied alignment state can be updated by using this button The button is disabled in basic tuning mode Motor Control Application Tuning MCAT Tool for 3 Phase PMSM Rev 1 01 2013 Freescale Semiconductor Inc co e N MCAT tool for 3 phase PMSM e Calculate the button is disabled by default In case that the tuning mode has changed from an expert to a basic mode and at least one of t
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