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dsPICDEM™ MC1H 3-Phase High Voltage Power Module User's

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3. contains details of the pin allocation Correct operation with the use of an extension cable can not be guaranteed as it may introduce additional noise If an extension is used it should be as short as possible and use screened cable The power module derives its low voltage power supplies from the control PCB The supplies on the isolated supply are taken directly from the control PCB via the 37 pin connector The supplies on the live side of the isolation barrier are derived using an isolating DC DC converter that is connected to the digital 5V supply input on the 37 pin connector In this way the power module may be used at any input voltage up to the maximum This arrangement is shown in Figure 1 4 DS70096A page 8 O 2003 Microchip Technology Inc Set Up and Operation FIGURE 1 4 POWER ELECTRONICS GATE DRIVE STAGES Power PCB 02 01647 POWER ELECTRONICS GATE DRIVE STAGES FAULT CONDITIONING DETECTION OF LIVE INCOMING GROUND AND LATCHING FEEDBACK CONNECTED TO CIRCUITRY SIGNALS CHASSIS 15V OUT 5V LINEAR REGULATOR ISOLATED ISOLATING HALL EFFECT LIVE DC DC 4 OPTOCOUPLERS LIVE CONVERTER CURRENT ISOLATED TRANSDUCERS Pin 19 amp 37 Pin 188 36 9V Power Rectify Supply Input Smooth and Floating Regulate Digital gy i io o o D 2 9 bd 24 Ja To Digital To Analog Circuits Circuits
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5. RR A J M fm O 2003 Microchip Technology Inc DS70096A page 21 dsPICDEM MC4H 3 Phase High Voltage Power Module The third device U2 is on the positive DC input connection from the rectifier within the input power stage see Figure 1 1 This is configured to have 2 turns of wire through it as delivered with LK2 installed This gives a maximum sensed current of 9 6A and a gain of 4 8A V U2 serves two purposes First is to provide the required current feedback information for controlling the active power factor correction PFC switches The second purpose is to provide detection of ground current faults i e when one or more of the inverter outputs become incorrectly connected to ground 1 4 6 Shunt Feedback Appendix A Sheet 3 1 4 6 1 INTRODUCTION In many applications the cost of isolated current transducers is prohibitive or the isolation is not required In these instances it is common practice to use resistive shunts The shunts can be placed in series with the output connections but this inevitably requires the use of level shifting and the creation of floating power supplies Therefore it is common to have shunts referenced to the same potential as the low voltage power supplies which is invariably the DC bus The disadvantage of using shunts referenced to the low side is that the feedback information is only available during certain
6. Two different gain settings for the inverter leg shunt and DC bus shunt feedback are implemented via LK5 12 These are located directly under the Danger High Voltage label on the PCB as shown in Section 9 The user should consult the schematics in Appendix A Sheet 3 to establish which links correspond to which signal Note that links must be changed in pairs e g LK5 and LK6 together or LK7 and LK8 together etc for correct operation See below RE X X LK5 LK6 LK5 LK6 e e LK5 e LK6 LK5 LK6 o e The scaling and trip levels for the inverter leg shunt signals are shown in the Table 1 7 TABLE 1 7 INVERTER LEG SHUNT SCALING SELECTION Links Open Links Shorted Bipolar Unipolar Bipolar Unipolar Scaling A V 1 09 1 09 24 24 Trip Level A 2 2 4 9 4 8 10 8 Note The shaded setting should not be used as it will not adequately protect the power devices from thermal overload The Scaling and the Trip Levels for the bus shunt signal is given in Table 1 8 TABLE 1 8 BUS SHUNT SCALING SELECTION Links Open Links Closed Scaling A V 1 08 2 39 Trip Level A 2 2 4 8 Changing the Hall sensors scaling is accomplished via solderable links e g LK1 LK2 and LK3 for U1 These are located adjacent to the transducers The links change the number of turns that pass through the transducer over a 3
7. However the PFC inductor and diode will be left in circuit and the input current will remain limited to 5A RMS and 8 9A Peak to protect the diode The user will also notice a large droop with increasing load when the PFC inductor is left in circuit Section 1 5 3 3 Bypassing The PFC explains how to modify the unit to bypass the PFC diode or the whole PFC stage With the PFC diode removed from the circuit the rated current increases to 6A RMS limited by the loss in the PFC inductor With the PFC inductor also removed from the circuit the rated current increases to 7A RMS limited by the NTC soft start thermistor and the diode bridge Note that with the PFC inductor removed from the circuit it is possible that less input power will be possible despite the higher permitted input current This is for two reasons Firstly because the power factor will be lower without the PFC inductor to smooth the input current Secondly the DC input over current protection will be more easily tripped by the surge of current that occurs on initial conduction of the Diode Bridge 1 3 4 DC Bus Voltage Ripple The unit has been designed with 3 x 330 uF DC bus capacitors in parallel thus giving approximately 1 mF of capacitance This value is substantially more than a fitting to a commercial drive of this rating when running off single phase 208V AC or higher when using the PFC Given the development nature of the system the capacitance was oversized to assist th
8. 1 va JULI 24d e Wilde 8 tr n lt nt Ais m SUO X GUI 13 o zn vse Huzi Hng bn SS ii A t 9 o e r oeoo a Bet D n sO i I AT S22 U D gr O O wo 3SN3S wal gt x NYH LO rr O aNov osi O LI as y os LO gt O 2003 Microchip Technology Inc 8 402 133HS GO ZA NOIS33A Lo 0SSdS ON ONIMVHQ e inpoW 42M04 2BD1J0A YIH 9SDYA 0J1u02 1030 dIY9OJOIW 31111 dl suonnjiog 18M04 IDWS INIA C0 Z7r910 5 0 dIHIOJINAN dsPICDEM MC4H 3 Phase High Voltage Power Module SZUZYI OH EAR QUA SALE e 4017873814 SE VE Y Hi NI 22A 108 8 3413 MA nc 01 T neg yugo ozn v Aen sg S MOL eza lk zen sna aaa gt M01 1Nnus a C 2 z 293 x HOI iNnus a C eza ASI 80 ICH d C sng 30A GI 219 sng oa C MOT LNNHST 4 CT KC H9IH LNNHST A C sng_30A HdA N Ha ADOS r Ha 8 dN
9. 3 18 20 Shinyokohama Kohoku Ku Yokohama shi Kanagawa 222 0033 Japan Tel 81 45 471 6166 Fax 81 45 471 6122 Korea Microchip Technology Korea 168 1 Youngbo Bldg 3 Floor Samsung Dong Kangnam Ku Seoul Korea 135 882 Tel 82 2 554 7200 Fax 82 2 558 5934 Singapore Microchip Technology Singapore Pte Ltd 200 Middle Road 07 02 Prime Centre Singapore 188980 Tel 65 6334 8870 Fax 65 6334 8850 Taiwan Microchip Technology Barbados Inc Taiwan Branch 11F 3 No 207 Tung Hua North Road Taipei 105 Taiwan Tel 886 2 2717 7175 Fax 886 2 2545 0139 EUROPE Austria Microchip Technology Austria GmbH Durisolstrasse 2 A 4600 Wels Austria Tel 43 7242 2244 399 Fax 43 7242 2244 393 Denmark Microchip Technology Nordic ApS Regus Business Centre Lautrup hoj 1 3 Ballerup DK 2750 Denmark Tel 45 4420 9895 Fax 45 4420 9910 France Microchip Technology SARL Parc d Activite du Moulin de Massy 43 Rue du Saule Trapu Batiment A ler Etage 91300 Massy France Tel 33 1 69 53 63 20 Fax 33 1 69 30 90 79 Germany Microchip Technology GmbH Steinheilstrasse 10 D 85737 Ismaning Germany Tel 49 89 627 144 0 Fax 49 89 627 144 44 Italy Microchip Technology SRL Via Quasimodo 12 20025 Legnano MI Milan Italy Tel 39 0331 742611 Fax 39 0331 466781 United Kingdom Microchip Ltd 505 Eskdale Road Winnersh Triangle Wokingham Berkshire England RG41 5TU Tel 44 118 921 5869 Fax 44 118 921 5
10. Caution Ovwing to thermal limitations of the inverter power devices the user should be very careful about changing the scaling of U3 and 4 If the user has robust current regulation and stall detection software then LK14 and LK17 may be used to allow higher output currents However the power devices will only be sufficiently cooled if PWM duty cycles do not exceed 75 below 10 Hz fundamental output frequency Under no circumstances should LK13 and LK16 be used as adequate thermal protection of the power devices is not provided Once the modification is complete install the lid ensuring all the screws are replaced 1 5 3 1 CHANGING VOLTAGE FEEDBACK AND TRIP SCALING The voltage feedback scaling is configured for the maximum range of input voltages If the user requires full ADC resolution at lower voltages then this can easily be accomplished by changing the high voltage resistors mounted on the top of the PCB Follow the procedure given in Section 1 5 2 Accessing The System for accessing the unit To change DC bus voltage scaling modify R10 R13 R14 Note if using the back EMF crossing detection circuitry see Section 1 4 7 3 Inverter Output Voltage Feedback and Sensorless Detection the user should also change the phase voltage feedback resistors to ensure consistent scaling To change VAC voltage scaling modify R12 and R15 To change phase voltage scaling modify R16 R20 In all ca
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12. 0A Brake Chopper Shunt 1 09 A V DC Bus Voltage 91 0 V V VAC Voltage 81 9 V V R Y B Inverter Output Voltages 92 0 V V If a large rate of change of current occurs due to the use of a load with low inductance the voltage across the self inductance of the shunts will cause an additional shunt voltage that will add to the shunt feedback signals o q q q q H s DS70096A page 12 O 2003 Microchip Technology Inc Set Up and Operation 1 2 7 FAULT Protection The following FAULT protection is provided which automatically disables all firing independent of the inputs on the 37 pin connector TABLE 1 4 FAULT PROTECTION Fault Source Nominal Trip LED Indicator Level R Y B Bottom Switch Current 4 8A cnrs DC Bus Current 4 8A DC Bus Voltage 410V Over Voltage Brake Switch Current 4 9A Brake Overcurrent Heat sink Over Temperature 65 C 150F Over Temperature Isolated DC Input Current Feedback 8 9A donan R Y Isolated Phase Current Feedback 4 4A If a large rate of change of current occurs due to the use of a load with low inductance the voltage across the self inductance of the shunts will cause trips to occur at a lower level than that stated To reset a FAULT assert the ISO RESET line of the 37 pin connector This should be done for a minimum time of 2 us The RESET must be carried out in coordination with the SPI handling routine of the dsPIC device to ensure correct
13. 1 range Tinned copper wire of a suitable current rating should be used Only one link at a time should be used or unpredictable current scaling will occur The user should ensure that the maximum length of lead protruding below the PCB is 4 mm for voltage clearance reasons The scaling and corresponding trip levels for U2 are shown in Table 1 9 TABLE 1 9 HALL EFFECT BUS CURRENT TRANSDUCER SCALING SELECTION LK 3 Closed LK2 Closed LK1 Closed Scaling A V 3 2 4 8 9 6 Trip Level A 5 9 8 9 17 8 mrt 2003 Microchip Technology Inc DS70096A page 31 dsPICDEM MC4H 3 Phase High Voltage Power Module If the user has bypassed the PFC diode or even the entire PFC section see Section 1 5 3 3 Bypassing The PFC then LK1 for U2 may be used to allow higher peak input currents while still ensuring ground FAULT protection is active Alternatively if the user wishes to develop a low power PFC application then LK3 may be used for improved feedback sensitivity The scaling of U3 and 4 is different from that shown above This is because the output leads are also passed through the transducers thereby giving an additional turn for increased sensitivity The scaling and trip levels for U3 and U4 are shown in Table 1 10 TABLE 1 10 INVERTER LEG CURRENT TRANSDUCER SCALING SELECTION LK 15 18 Closed LK14 17 Closed LK13 16 Closed Scaling A V 2 4 3 2 4 8 Trip Level A 4 4 5 9 8 9
14. BYTE TO SEND 3 GPIO SDO GPIO SCK GPIO SDO send bit 2 GPIO SCK BYTE TO SEND 2 GPIO SDO GPIO SCK ADCONO GO Start A D conversion Channel 0 GPIO SDO send bit 1 GPIO SCK BYTE TO SEND 1 GPIO SDO GPIO SCK GPIO SDO send bit 0 GPIO SCK BYTE TO SEND 0 GPIO SDO GPIO SCK while ADC is still converting Channel 0 send control word OxF9 bsf bsf bcf nop bsf bcf nop bsf bcf nop GPIO SCK send bit7 GPIO SDO GPIO SCK GPIO SCK send bit6 GPIO SCK GPIO SCK send bit5 GPIO SCK O 2003 Microchip Technology Inc DS70096A page 51 dsPICDEM MC4H 3 Phase High Voltage Power Module bsf GPIO SCK send bit4 bcf GPIO SCK nop bsf GPIO SCK send bit3 bcf GPIO SCK nop bsf GPIO SCK send bit2 bcf GPIO SDO nop bcf GPIO SCK nop bsf GPIO SCK send bitl bcf GPIO SCK nop bsf GPIO SCK send bito bsf GPIO SDO bcf GPIO SCK conversion of channel 0 now complete movf ADRES W movwf BYTE TO SEND goto Main Do it again end DS70096A page 52 2003 Microchip Technology Inc Appendix NOTES O 2003 Microchip Technology Inc DS70096A page 53 MICROCHIP WORLDWIDE SALES AND SERVICE AMERICAS Corporate Office 2355 West Chandler Blvd Chandler AZ 85224 6199 Tel 480 792 7200 Fax 480 792 7277 Technical Support 480 792 7627 Web Address http www microchip com Atlanta 3780 Mansell Road Suite 130 Alpharetta G
15. Frequency modulation This was considered given that the pulse distortion by the optocouplers ceased to be an issue However concerns about how the band width of the feedback could be maintained over the 8 bit data range led to its rejection The actual hardware is described below U34 The PIC12C671 Note that the PIC12C671 is reset whenever the RESET line is asserted as this pin has been configured as the MCLR This allows correct synchronization of the SPI with the dsPIC device to be established The RESET line must be asserted for a minimum pulse width of 2 us R12 R15 R122 These form a potential divider so that the maximum expected voltage on VAC SENSE is 4 5V C43 This acts to smooth out any noise spikes on the VAC SENSE POINT in combination with R12 R15 and R122 R10 R13 R14 R140 R141 These form a potential divider so that the maximum expected voltage on BUS SENSE is 4 5V Note that HALF BUS SENSE is used by the sensorless position detection comparators see Section 1 4 7 3 Inverter Output Voltage Feedback and Sensorless Detection C57 This acts to filter out any noise spikes on the DC bus voltage sensing circuit D40 D42 Clamping diodes to protect the PIC12C671 inputs OOOO O 2003 Microchip Technology Inc DS70096A page 25 dsPICDEM MC1H 3 Phase High Voltage Power Module U16 U17 Low current 1 6 mA medium speed 1 MHz optocouplers to provide the isolation
16. Operation 1 1 INTRODUCTION The Microchip dsPICDEM MC1H 3 Phase High Voltage Power Module is intended to aid the user in the rapid evaluation and development of a wide variety of motor control applications using the dsPIC microcontroller The design of the system includes Microchip analog components as well as a PIC microcontroller used to provide isolated voltage feedback The main components of the system are shown in Figure 1 2 The rated continuous output current from the inverter is 2 5A RMS This allows up to approximately 0 8 kVA output when running from a 208V to 230V single phase input voltage in a maximum 30 C 85F ambient temperature environment Thus the system is ideally suited to running a standard 3 Phase Induction Motor of up to 0 55 kW 0 75 HP rating or an industrial servomotor of slightly higher rating The power module is capable of driving other types of motors and electrical loads that do not exceed the maximum power limit and are predominantly inductive Furthermore single phase loads can be driven using 1 or 2 of the inverter outputs The unit is capable of operating from any AC voltage up to a maximum of 265V Operation at voltages beneath 208V requires that the output power is reduced owing to inverter output and AC input stage current limits A more detailed explanation of power limitations is given in Section 1 4 Detailed Description of Operation The user should read Section 1 3 Current and P
17. doubt consult your supplier WARNING This system must be earthed grounded at all times CAUTION The system should not be installed operated serviced or modified except by qualified personnel who understand the danger of electric shock hazards and have read and understood the user instructions Any service or modification performed by the user is done at the user s own risk and voids all warranties WARNING The output terminals are NOT isolated from the incoming AC mains supply and may be at up to 410V with respect to ground regardless of the input mains supply voltage applied These terminals are live during operation AND for 3 minutes after disconnection from the supply Do not attempt to access the terminals or remove the cover during this time Note that this same shock hazard applies to any external brake resistor connected which will also be live and therefore protection equivalent to double insulation should be provided WARNING The unit may obtain power through the output terminals if these are connected to a rotating motor acting as a generator If this is the case then the previous warning also applies i e the output terminals are live when connected to the generator and for 3 minutes after the generator has been stopped Note that this case can arise even when the unit has been disconnected from the incoming AC mains supply CAUTION If a motor is connected to the output of this unit the frame should be connecte
18. modules both have dedicated fault inputs that can be configured to shutdown PWM outputs to their inactive state The operation of the fault action is described below D35 D38 and R114 These form an active high wire OR of all four live FAULT signals R114 provides a passive pull down during normal operation The resulting FAULT signal is used to directly shutdown the inverter gate drive ICs via their shutdown logic input R113 013 R110 D34 and Q14 These components act to shutdown the PFC and brake chopper during a FAULT Q14 must be on for the detector stage of their optocouplers to be powered Under normal conditions D34 and R110 provide the base current for Q14 Ifthe FAULT line is asserted causing Q13 to turn on or if the 15V supply drops below approximately 10V then Q14 turns off U15 and R151 If FAULT is asserted current flows via R151 to cause the open collector output of U15 to turn on This indicates back to the isolated side that a FAULT has occurred on the live side R176 and Q15 If a Hall over current is detected on the isolated side the base current for Q15 that normally flows via R176 is removed As all the firing command optocoupler emitters return via Q15 when Q15 is off no firing can take place D43 D44 and R172 These form an active low wire OR of the isolated and live fault indications for feedback to the dsPIC device 1 4 9 2 INVERTER SHUNT OVER CURRENT The feedback signals from
19. or greater voltage rating Once the modification is complete install the lid ensuring all the screws are replaced Note that the maximum continuous limit on input current increases to 7A RMS limited by the soft start NTC 5 3 4 ACCESSING THE ADDITIONAL NON ISOLATED FEEDBACK SIGNALS All the non isolated feedback signals are brought to a series of links that run along the edge of the isolation barrier In order to access these signals the user should rigidly carry out the procedure given below Failure to do so could represent a safety hazard to the user as the isolation barrier is bridged Follow the procedure given in Section 1 5 2 Accessing The System for accessing the unit Disconnect the input wiring from the AC supply outlet Wire in a safety isolation transformer with a suitable rating between the AC supply outlet and the AC input to the system The supply to the unit should now be floating The user should satisfy themselves that the isolation transformer is wired correctly and the insulation is intact Ensure that the earth ground continuity is maintained to the unit Solder a wire between J13 and J5 The wire should be 1 0 1 5 mm 18 16 AWG with a minimum voltage rating of 600V and suitable for operation up to 105 C It should be the standard color used for earth ground cabling in the user s country e g green for U S This link is connecting the DC bus to the incom
20. portions of the PWM cycle In order to extract the required information the shunts must be sampled at precise intervals This feature has been allowed for in the dsPIC device by the inclusion of sample and hold amplifiers in the ADC module that can be triggered from the PWM module see the dsPIC30F Family Reference Manual for details On high voltage low power systems it may be possible to use shunts of high enough value to have sufficient voltage for direct input to an ADC More commonly the dissipation in the shunt dictates the use of low resistance values and appropriate amplification If too high the voltage drop across the shunt can also cause problems for driving the power transistors For low gains it may be possible to use single ended amplification Differential amplification is required as the gains increase in order to provide a signal of sufficient quality and accuracy The Microchip MCP6022 dual and MCP6024 quad parts have been used in the design for providing the differential amplification They are an ideal choice for the following reasons Low power consumption 1 mA typical amp this is especially important where the power supplies are derived from the DC bus with a resistor zener network Low offset voltage 0 5 mV max Rail rail inputs and outputs No gain inversion with negative inputs this is important as it is common for the amplifier to have negative spikes on its inputs that occur d
21. provides this feature The algorithm should monitor rotor speed and cause a system trip if the rotor speed is at or near zero for greater than an appropriate length of time while the inverter is energized A stall trip time of 2 seconds is suggested mf 2003 Microchip Technology Inc DS70096A page 13 dsPICDEM MC4H 3 Phase High Voltage Power Module 1 2 9 Field Weakening If the user is operating a brushless permanent magnet motor using field weakening by employing phase advance great care should be taken If a FAULT trip occurs firing will stop and the full back EMF magnitude due to the motor s speed will be present on the output terminals Should the peak of the back EMF be above the DC bus sudden uncontrolled motor braking will occur The DC bus will rise in an uncontrolled manner possibly causing damage to both power devices and the DC bus capacitors A speed greater than that which would produce a peak back EMF of greater than 450V with no field weakening should not be used This should adequately protect the unit If using the auxiliary DC input the user should check the rating of the power supply and adjust this speed accordingly or use a series blocking diode of suitable rating The same care should be taken with separately excited brushed DC motors if employing field weakening at high speed If the field current were to be increased in error a similar braking phenomenon may occur if the back EMF rises above the DC bus T
22. side switch is on and the low side switch is therefore off D28 blocks reverse current flow that would result from the bus voltage present on the inverter output This kind of floating supply is usually referred to as a bootstrap see Figure 1 7 This circuit is commonly used because it is both efficient and economical It is assumed that any bootstrap initial priming or any necessary refresh is carried out in software by the dsPIC device This is discussed in Section 1 2 5 Power Device Switching Frequencies FIGURE 1 7 BOOTSTRAP SUPPLY R51 D vi enis Bootstrap C17 m Supply Ofsv ins Q4 EO R4 R33 D21 R39 and R38 These components aid in the correct control of the gate of the high side power device The same circuit is repeated for the low side switch using R54 D27 R57 and R58 Generally speaking the larger value of gate resistance used the slower the device switches Slower switching reduces over undershoots and consequently EMI but increases switching loss and hence device junction temperature Turning the device on uses R39 and R38 Turning the device off uses D21 R33 in parallel with R39 and R38 In this way different turn on and turn off resistance can be used to optimize switching performance D31 This is a high voltage clamping diode located directly adjacent to the IC It is necessary to ensure correct operation of the IC during extreme transients that can occur during a
23. switches and should be avoided See Figure 1 5 FIGURE 1 5 OUTPUT CURRENT LIMITS 1 Continuous Operation 2 Intermittent Operation 3 Region to be Avoided Peak Output Current 20 Hz Output Frequency 1 3 2 Input Current Limits Using The Active PFC The active PFC circuit is capable of 5A RMS input 7 1A Peak at any AC input voltage within the entire permitted operating range voltage temperature and 50 kHz modulation frequency Note This is only true provided the correct half sinusoidal input current waveshape is being followed and the DC bus is being correctly regulated to be above the peak of the AC supply Thus the input power and neglecting losses the output power when using the PFC is linearly proportional to the input voltage A commercial application will often maintain constant output power over the universal input voltage range of 88 265 VAC This constant power characteristic was not designed into the system in order to limit the size and cost of the PFC inductor and switches For a fixed RMS input current of the correct half sinusoidal shape and fixed modulation frequency the user should note the following comments as to how different parts of the PFC circuit are thermally loaded PFC inductor thermal loading is relatively insensitive to variations in AC input voltage or regulated DC bus output voltage PFC switches are more heavily thermally loaded the larger the difference b
24. synchronization of the serial interface providing the isolated voltage feedback see Section 1 4 7 2 Isolated Voltage Feedback Note If SHUNT OVERCURRENT trips are occurring but not HALL OVERCURRENT trips this may indicate that an inverter Shoot Through is occurring The user should immediately remove AC power from the system and check that the correct 2 us dead time exists on the inverter firing signals using an oscilloscope 1 2 8 Operation at Low Output Frequencies and Stall As far as the inverter power devices are concerned it is the instantaneous temperatures of their junctions that matter for correct operation and reliability As the current that flows through a particular power device changes through an electrical cycle so does the loss At high fundamental output frequencies e g 60 Hz the devices have sufficient thermal mass to smooth out much of the effect of the variation in loss so that the peak device junction is due to the much lower average dissipation As the output frequency reduces the peak device junction temperature reaches the worst case loss It is common practice to include a stall detection algorithm in software This is designed to not only protect the power components but also the motor from thermal overload As it is impractical to include stall detection in hardware that maintains flexibility for development but still provides 10096 protection it is assumed that the software in the dsPIC device
25. 200 34 A simple multilayer winding is used which results in moderate copper loss but significant self capacitance 142 turns of 1 12 mm diameter enameled copper wire is used The design offers a good compromise between cost core loss and size for this application The nominal inductance is 1 15 mH at 5A Q1 Q2 Two 500V TO220 MOSFETS connected in parallel As the tabs of the devices are not isolated a thermally conductive insulator is used When closed Q1 and Q2 increase the energy stored in the inductor L2 When open energy stored in the inductance is transferred to the DC bus capacitors C3 C5 Energy is also drawn from the AC supply during this time By appropriate control of the Switches the input current wave shape can be profiled to obtain good power factor and low harmonic distortion D1 A 600V DO 220 diode optimized for use at high switching frequency As the tab of the device is not isolated a thermally conductive insulator is used C1 R1 R2 A snubber that acts to damp high frequency oscillations and limit the rate of change of voltage across Q1 and Q2 C3 C4 C5 450V 330 mF electrolytic capacitors which act as the main DC bus energy storage capacitors C2 C6 C7 400V 1mF film capacitors which act to source the high frequency component of current for the PFC stage Note that the faces of these components are not insulated e U19 Microchip TC1412N gate drive IC This contain
26. 820 05 30 03 DS70096A page 54 O 2003 Microchip Technology Inc YI 1BUR This datasheet has been downloaded from www EEworld com cn Free Download Daily Updated Database 100 Free Datasheet Search Site 100 Free IC Replacement Search Site Convenient Electronic Dictionary Fast Search System www EEworld com cn All Datasheets Cannot Be Modified Without Permission Copyright O Each Manufacturing Company
27. 9S11 dN 9S11 yn en BEN eon o 0 Ye 6 ENT ees e 0 N sO z o 993 o 995 ur DE S22 DE gee ar 00 oz Oe 0 4 0 oir op nus E5 rv LO od a o gt anov os L Or Ae v osi LO ag vrosi gt BEIEN BEIEN 0H ou d e o 00A SA adA SA e NIH 2 y7 NIH EJ 7 ES 4017473914 E NA ooa ue A za Y SSA MOI A084 qud Ssa 023 gt 01 anes Jung oH Lange uoo 919 19 119 ro ven zen LAT SE So S gt 2 gt 2 S S VVV 9 VVV 4 ica e sna aaa C Pl gt 8 SZ MOT ANS C d S 3S2 S 82i T 2 225 AT m 2 7 BSS HOIHT LNNHST 4 lt gt s lt Bee I 5 Y AAA SA Y ASI IER D vo me 2 28 8 a 8 S zSz 3 lt e sng7o0A 2003 Microchip Technology Inc DS70096A page 40 Appendix 8 30 133HS GO ZA NOISY3A Lo 0SSdS ON ONIMVUG 9 npoy 1 MOd abo yo YIH spud 01 U09 JOJOW ANYIOJDIN 31111 dl SUOIRNIOS JIMOY OWS d 1NnHS sna JAJA C0 Zv910 0 34 GAZ YC09d2W JA 8 3A 8 3A A FAA WT 63 s lt N RSS yogs use ZZ09d9N G t Ee lt NVV var uns AVY T solu Ion Le T ut 138440 LNNHS geo a u09s uss 1NnHS 33v38 JARA azz MM Av MOT LNNHS diva 2 LOLH 0014 o EE uec zua DECH A cou ZLA Eve
28. A 30022 Tel 770 640 0034 Fax 770 640 0307 Boston 2 Lan Drive Suite 120 Westford MA 01886 Tel 978 692 3848 Fax 978 692 3821 Chicago 333 Pierce Road Suite 180 Itasca IL 60143 Tel 630 285 0071 Fax 630 285 0075 Dallas 4570 Westgrove Drive Suite 160 Addison TX 75001 Tel 972 818 7423 Fax 972 818 2924 Detroit Tri Atria Office Building 32255 Northwestern Highway Suite 190 Farmington Hills MI 48334 Tel 248 538 2250 Fax 248 538 2260 Kokomo 2767 S Albright Road Kokomo IN 46902 Tel 765 864 8360 Fax 765 864 8387 Los Angeles 18201 Von Karman Suite 1090 Irvine CA 92612 Tel 949 263 1888 Fax 949 263 1338 Phoenix 2355 West Chandler Blvd Chandler AZ 85224 6199 Tel 480 792 7966 Fax 480 792 4338 San Jose Microchip Technology Inc 2107 North First Street Suite 590 San Jose CA 95131 Tel 408 436 7950 Fax 408 436 7955 Toronto 6285 Northam Drive Suite 108 Mississauga Ontario L4V 1X5 Canada Tel 905 673 0699 Fax 905 673 6509 ASIA PACIFIC Australia Microchip Technology Australia Pty Ltd Marketing Support Division Suite 22 41 Rawson Street Epping 2121 NSW Australia Tel 61 2 9868 6733 Fax 61 2 9868 6755 China Beijing Microchip Technology Consulting Shanghai Co Ltd Beijing Liaison Office Unit 915 Bei Hai Wan Tai Bldg No 6 Chaoyangmen Beidajie Beijing 100027 No China Tel 86 10 85282100 Fax 86 10 85282104 China Chengdu Microchip
29. All the above requirements can be met by the use of an inexpensive PIC microcontroller along with two additional low current optocouplers In this case an 8 pin PIC12C671 microcontroller was chosen as it has the necessary ADC on board and is low cost Full advantage could be taken of the on board 4 MHz RC clock Three different methods for representing the magnitude of the two signals were considered In all cases only two optocouplers were required A serial communication interface A simplified two wire SPI Clock and Data Out It would operate as a master with the dsPIC device as the slave Given the PIC12C671 does not have a hardware SPI module the interface would be reproduced in software The code latency was to be used for ADC acquisition and conversion timing This was the method chosen and the code is given in Appendix B along with a diagram showing the transmission data cycle Note The clock and data signals for the SPI interface are inverted due to the opto isolators The user code should account for this by sampling the data on the falling clock edge and inverting the received data Pulse width modulation at constant frequency This was rejected partly due to concerns over distortion of the pulse width by economic optocouplers Also it was thought that it would not be possible to provide the required bandwidth while maintaining the 8 bit resolution of the captured data given the lack of a hardware PWM module
30. Control PCB 02 01648 Note that the incoming digital OV from the development board is grounded within the power module as shown in Figure 1 4 to ensure user safety When a PC or any other device is connected to the control board there is therefore the possibility of a ground loop occurring If this is suspected the user should first try to eliminate the stray magnetic field causing the problem by relocating the offending transformer or by using shielding If this is not possible then the equipment connected to the development board should be isolated from the digital OV Position and speed feedback transducers are connected to the control board directly and not via the power module No electrical isolation is provided on the control board for these signals and so the transducers must be isolated Consult the development board documentation for details of signal interfacing and how to connect in circuit emulators and debugging equipment O 2003 Microchip Technology Inc DS70096A page 9 dsPICDEM MC1H 3 Phase High Voltage Power Module 1 2 4 Power Up Power Down Sequence The user should ensure that the following sequence are followed 1 241 POWER UP SEQUENCE With the development board plugged in turn on the power supply feeding the control PCB if not already on D D One or more of the fault lights may illuminate This is normal Turn on the AC supply to the power module Reset the system by a
31. FAULT In combination with R38 and R53 it ensures Pin6 of U22 never goes more than 5V negative with respect to Pin2 R27 and R26 These resistors form a passive Gate Emitter pull down to ensure the IGBTs stay off if the low voltage power supplies are not present 1 4 4 Brake Chopper Appendix A Sheet 1 Clearly if the motor is used as a brake or generator any average power that flows back from the inverter must have somewhere to go As the mains input and power conditioning stages have only been designed for importing power a means of dissipating the excess power has been provided The most common form of brake chopper has been implemented and is described below Q10 A 600V N Channel IGBT transistor with anti parallel diode This is of the same type as used for the inverter for economic reasons In practice a slower switching device may be used which has lower conduction loss Apart from acoustic noise reasons there is no reason to modulate the device at high frequency As the tab of the device is not isolated a thermally conductive insulator is used 2003 Microchip Technology Inc Set Up and Operation e D3 A 8A 600V diode required to freewheel the current around the resistor due to it s inductance As the tab of the device is not isolated a 3W 25mQ shunt resistor through which the low side switch and diode returns to the DC bus The shunt is used for FAULT protection and optionally for an alternative feedb
32. IC12C671 MCLR line Active Low RESET TP 16 LIVE 15V power supply 15V TP 17 Live 5V power supply 5V TP 18 ISOLATED High reference used for FAULT trips ISO HIGH REF TP 19 ISOLATED Low reference used for FAULT trips ISO LOW REF TP 20 LIVE Star Reference Point for Low Voltage PSUs DS70096A page 36 2003 Microchip Technology Inc Set Up and Operation 1 7 USER SIGNAL CONNECTOR PINOUT 37 PIN D TYPE Pin Function Net Name Siba Isolated 1 Not Used 2 Yellow Phase Shunt Current Feedback Y_SHUNT Output No if LK20 installed 3 DC Bus Shunt Current Feedback BUS_SHUNT Output No If LK22 installed 4 Not Used 5 Yellow Phase Voltage Feedback Y_VPH_SENSE Output No If LK25 installed 6 Blue Phase Back EMF crossing B CROSSING Output No if LK27 installed 7 Red Phase Back EMF crossing R_CROSSING Output No if LK29 installed 8 Rectifier Output Voltage VAC Feedback IVAC SENSE Output No if LK31 installed 9 Analog 5V from control PCB 2 ISO_A 5V Input Yes 10 PFC Switch Firing Command CMD_PFC Input Yes 11 Blue Phase Top Switch Firing Command CMD_B_TOP Input Yes 12 Yellow Phase Top Switch Firing Command CMD_Y_TOP Input Yes 13 Red Phase Top Switch Firing Command CMD_R_TOP Input Yes 14 Active Low Serial Clock ISO SCLK Output Yes 15 Active Low Fault FAULT_ISO Outpu
33. IM and MPLAB SIM30 simulators MPLAB IDE Project Manager and general editing and debugging features Programmers The latest information on Microchip device programmers These include the PRO MATE II device programmer and PICSTART Plus development programmer O 2003 Microchip Technology Inc DS70096A page 3 dsPICDEM MC4H 3 Phase High Voltage Power Module CUSTOMER SUPPORT Users of Microchip products can receive assistance through several channels Distributor or Representative Local Sales Office Field Application Engineer FAE Corporate Applications Engineer CAE Hotline Customers should call their distributor representative or field application engineer FAE for support Local sales offices are also available to help customers See the back cover for a list of sales offices and locations Corporate Applications Engineers CAEs may be contacted at 480 792 7627 In addition there is a Systems Information and Upgrade Line This line provides system users a list of the latest versions of all of Microchip s development systems software products Plus this line provides information on how customers can receive any currently available upgrade kits The Hotline Numbers are 1 800 755 2345 for U S and most of Canada 1 480 792 7302 for the rest of the world DS70096A page 4 2003 Microchip Technology Inc dsPICDEM MC1H 3 PHASE MICROCHIP HIGH VOLTAGE POWER MODULE Chapter 1 Set Up and
34. ING SIGNAL ISOLATION APPENDIX A SHEET 5 Either optical or transformer based isolation strategies can be used for transmitting gate firing commands For this design it was decided to use optocouplers as it was possible that a particular firing command may be used for commutation as opposed to high frequency modulation This could lead to transformer saturation at low speeds The hardware implemented is described below U6 U13 HCPL4503 optocouplers These parts were chosen to provide good noise immunity while requiring low current consumption on the output side Speed was also a consideration so that too much delay or pulse distortion was not introduced R153 R160 Pull up resistors for the open collector outputs of the optocouplers R162 169 Series resistors to ensure at least 18 mA flows through the emitter stage of the optocouplers Note that the ground return is via a transistor Q15 that allows shutdown during detection of an over current from one of the isolated Hall effect current transducers U32 and U33 Schmitt triggered inverters which clean up the edges from the outputs of the optocouplers 1 4 8 3 LOW VOLTAGE POWER SUPPLIES APPENDIX A SHEET 5 AND 8 The requirement for operation over a wide range of input voltage resulted in using the 5V supply coming from the control board as the power source for all the low voltage power supplies This was true for both the isolated and live sides of the system The power su
35. IP HIGH VOLTAGE POWER MODULE Table of Contents Safety Nod A ao iii MAIDEN Ern 1 Chapter 1 Set Up and Operation 1 4 veel e OT mI I 5 1 2 Using The Motor Control 3 Phase High Power Module 7 1 3 Current and Power Limitations een 14 1 4 Detailed Description of Operation 17 1 5 Modifying The Board AA ae KA Ee nn ane 30 1 6 est Points eb ete e De aed se e est nene de S ti ded o defe ocu uda 36 1 7 User Signal Connector Pinout 37 Pin D Type 37 Appendix A Circuit Diagrams entran rre e a keine u 39 Appendix B Source COJE cional el oodd ond dn Ad 47 Worldwide Sales and Service enr 54 O 2003 Microchip Technology Inc DS70096A page v dsPICDEM MC1H 3 Phase High Voltage Power Module NOTES DS70096A page vi O 2003 Microchip Technology Inc dsPICDEM MC1H 3 PHASE MICROCHIP HIGH VOLTAGE POWER MODULE Preface This chapter contains general information about this manual and contacting customer support HIGHLIGHTS Topics covered in this chapter About this Guide Warranty Registration Recommended Reading The Microchip Web Site Development Systems Customer Notification Service Customer Support ABOUT THIS GUIDE Document Layout This document describ
36. MICROCHIP dsPICDEM MC1H 3 Phase High Voltage Power Module User s Guide D eee 2003 Microchip Technology Inc DS70096A Note the following details of the code protection feature on Microchip devices Microchip products meet the specification contained in their particular Microchip Data Sheet Microchip believes that its family of products is one of the most secure families of its kind on the market today when used in the intended manner and under normal conditions There are dishonest and possibly illegal methods used to breach the code protection feature All of these methods to our knowledge require using the Microchip products in a manner outside the operating specifications contained in Microchip s Data Sheets Most likely the person doing so is engaged in theft of intellectual property Microchip is willing to work with the customer who is concerned about the integrity of their code Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code Code protection does not mean that we are guaranteeing the product as unbreakable Code protection is constantly evolving We at Microchip are committed to continuously improving the code protection features of our products Attempts to break microchip s code protection feature may be a violation of the Digital Millennium Copyright Act If such acts allow unauthorized access to your software or other copyrighted work you m
37. O Ar 4400 24001 4u00L ange i QNS SSO 06 8c ZC LNOA NIA Hn ei dIWSOT18LIM sn eo o o AG gt ASI va v ASI A 4 e a p e D e e a 9 zn en 6n on zin cin 9n un vn eent ven zen 6zn n gzn zn zen Gzn ozn in 20001 34001 34001 3400 34001 3400 34004 3u00L 24001 34004 3900L 4u00L 34004 34001 4001 4u00L 34004 40004 20001 34004 949 Slo 29 49 TL 149 89 499 999 799 659 959 99 0v2 6 9 9 LT 979 SCH uo e e e e e v AS 2003 Microchip Technology Inc DS70096A page 46 dsPICDEM MC1H 3 PHASE MICROCHIP HIGH VOLTAGE POWER MODULE Appendix B Source Code FIGURE B 1 DATA TRANSMISSION CYCLE CONTROL WORD ADC CHO ADC CH1 VDC Bus IVAC e No ae e 1 Cycle of Data 128 us Note The data transmitted via the SPI interface is inverted by the opto isolators The user software should invert the received data O 2003 Microchip Technology Inc DS70096A page 47 dsPICDEM MC1H 3 Phase High Voltage Power Module B 1 PIC MCU CODE AND DATA CYCLE DIAGRAM FOR SERIAL INTERFACE k k k k k k k k k k k k k k k k k k k k k K k k k KOK KO KOK K KOK KOK K K K KOK OK K K KOK OK KOK K KOK K K KO k k R 50_10_v3 ASM k k k kc k k k k k k k k k k k k k k k k k k k k k K K KOK K k K KO KOK K K KO KOK K K K KOK OK KOK K KOK K K KO kk R Smart Power Solutions LL
38. ODE DS70096A page 48 2003 Microchip Technology Inc Appendix Initial Capture before starting SPI transmission aquire amp convert ADC ch0 BUS SENSE movlw 0x41 set Fosc 8 A D enable ch0 select movwf ADCONO begin sampling cho movlw 0x04 walt for approx 20us aquisition time movwf STARTUP TIMER delay decf STARTUP TIMER F btfss STATUS Z goto delay bsf ADCONO GO Start A D conversion Channel 0 finish 1st conversion btfsc goto movf movwf nop ADCONO GO wait for end of conversion flag finish 1st conversion ADRES W BYTE TO SEND extra wait before starting new aquisi tion k k k k k RARA k k k k k k k k k k k k k k k ck k kc k k k k k k ck K KOK K K K KO K K K K KO KOK OK K KOK kkk R K K Main movlw movwf 0x51 Fosc 8 A D enabled ch 2 selected ADCONO begin sampling channel 2 VAC SENSE begin to transmit value from channel 0 bcf bsf btfsc bsf bcf bcf bsf btfsc bsf bcf bcf bsf btfsc bsf bcf bcf bsf btfsc bsf bcf GPIO SDO send bit 7 GPIO SCK BYTE TO SEND 7 GPIO SDO GPIO SCK GPIO SDO send bit 6 GPIO SCK BYTE TO SEND 6 GPIO SDO GPIO SCK GPIO SDO send bit 5 GPIO SCK BYTE TO SEND 5 GPIO SDO GPIO SCK GPIO SDO send bit 4 GPIO SCK BYTE TO SEND 4 GPIO SDO GPIO SCK O 2003 Microchip Technology Inc DS70096A page 49 dsPICDEM MC4H 3 Phase High Voltage Power Module start ADC convertion on ch2 whi
39. OZY N 8074 301 Neem Al e a gozy t Be 438 MOT OSI O 2003 Microchip Technology Inc DS70096A page 44 Appendix 8 407 133H8 GO ZA L0O OGSdS NOIS33A ON ONIMV3Q einpow Jewog ebD0j oA UBIH spud 04ju02 10 0W d u2049 WN 37111 d11 suonnjos JIMOJ IDWS 1Z99ZLOId 3SN3S7 SNA gei 249 49 13538 338 H9IH E 1d9 d9 vivd 3A 3SN3S OVA 71099 497 119873AM7 ESSA aaa yen OvG1V8 mw y AS JAJA GO E POLOS EO A 72 169 3SN3S Deal 3SN3S HdA 8 Du TZLY x08L 4002 AN E ova 1NIOd 3SN3S Deal gt l AS 3N 769 3SN3S HdA A D 9Nissouo 8 gt E 3SN3S HdA 8 3 3SN3S SNE Amen AG n anissoyo 4 L gt 3SN3S HAT A juo amp WAWA 3SN3S ShH 41VH 3SN3S HdA Y Ss ovs va Y y AAA 9Nissou27u gt Lv 3SN3S HdA N 3SN3S SNE 41VH AG dIHOOYOIN A orz K AZ8 EI 3001 ANN aly c HdA 8 01 218 azg NAVV Di 2001 61H Hd a7 A pele 178 ieu 3001 AA oza Joan DS70096A page 45 O 2003 Microchip Technology Inc dsPICDEM MC1H 3 Phase High Voltage Power Module
40. P 13th April 2003 Assembled with MPLAB v6 13 k k k k k k k k k k k k k k k k k k k k Kk k k K e K K KOK K K K K KOK RR kc kc kc K KOK OK kkk kk K R KO kk R This program continuously converts two ADC channels ANO amp AN2 and writes the results out via SPI followed by a control word OxF9 The software latency of the SPI transmission is used to fulfill the aquire conversion amp wait time of the ADC module for maximum data transmission rate If transmission is corrupted MCLR is asserted to re sync D D D D D transmission therefore no watchdog is required SPI clock SCK is GP5 pin 2 idle low and data is valid on the falling edge SPI data out line SDO is PGP4 pin 3 Use config word 0xE4 when programming k k k ce k k k k k ce k k k k k ce ce k ck ce k k k KARA k k k K lt lt list p 12c671 Include file change directory if needed include p12c671 inc BYTE TO SEND EQU 0x20 STARTUP TIMER EQU 0x21 SCK EQU 0x05 SDO EQU 0x04 Start at the reset vector org 0x000 Start begin in bank0 initially clrf GPIO Clear GPIO bsf STATUS 5 select banki movlw OxOf movwf TRISIO GP5 GP4 outputs also in bank 1 moviw 0X02 ADO AD1 and AD2 are analog channels movwf ADCON1 with VDD and VSS references call 0x03ff factory programmed data to trim movwf OSCCAL internal oscillator clrf STATUS select bank0 FOR REST OF C
41. Section 1 4 9 2 Inverter Shunt Over current 1496 HALL OVER CURRENT The signals from the three Hall effect current transducers are used to provide protection against overload wiring and earth ground faults The two inverter output Hall effect sensors U3 and U4 are checked for both positive and negative current The DC input Hall effect sensor U2 is only checked for positive current for obvious reasons The circuitry to implement the trip is shown on Appendix A Sheet 6 Being similar to that described in Section 1 4 9 2 Inverter Shunt Over current it requires little further explanation The one difference is that the input signals to the comparator are divided down in order to stay within the input voltage limitations of the comparators when running from 5V O 2003 Microchip Technology Inc DS70096A page 29 dsPICDEM MC4H 3 Phase High Voltage Power Module 1 5 MODIFYING THE BOARD 1 5 1 Introduction Certain modifications have been allowed for in the design of the system as described below Clearly any additional modifications that the user chooses to make can not be guaranteed to be functional or safe It is assumed that relevant qualified personnel only will use the system 1 5 2 Accessing The System Before removing the lid of the system the following procedure should be rigidly followed Turn off all power to the system Wait a minimum of 3 minutes so that the internal discharge circuit has r
42. Set Up and Operation 1493 DC BUS OVER VOLTAGE The feedback signal derived for the DC bus voltage see Section 1 4 7 Voltage Feedback Appendix A Sheets 1 6 and 7 is used to detect an over voltage condition The threshold is set at approximately 410V in order to protect the power devices and the DC bus capacitors A similar circuit as described in Section 1 4 9 2 Inverter Shunt Over current is used 1494 BRAKE OVER CURRENT The feedback signal derived from the brake chopper shunt is used to detect an over current The threshold is set at 6 1 A The circuitry used to implement the trip is similar to that described in Section 1 4 9 2 Inverter Shunt Over current 1495 HEAT SINK OVER TEMPERATURE To protect the power devices from thermal overload a heat sink temperature trip is included The trip temperature is set at nominal value of 65 C 150F The circuitry used to implement this is described below U1 AMicrochip TC622EAT temperature trip IC This IC only requires an external resistor R34 to set the nominal trip temperature As the version chosen is packaged in a TO220 this is easily mounted along with the other power devices to the heat sink This ensures excellent thermal coupling As the tab of the device is not isolated a thermally conductive insulator is used R116 and C42 These filter the output of U1 to prevent false tripping due to noise Latching and indication is identical to that described in
43. Technology Consulting Shanghai Co Ltd Chengdu Liaison Office Rm 2401 2402 24th Floor Ming Xing Financial Tower No 88 TIDU Street Chengdu 610016 China Tel 86 28 86766200 Fax 86 28 86766599 China Fuzhou Microchip Technology Consulting Shanghai Co Ltd Fuzhou Liaison Office Unit 28F World Trade Plaza No 71 Wusi Road Fuzhou 350001 China Tel 86 591 7503506 Fax 86 591 7503521 China Hong Kong SAR Microchip Technology Hongkong Ltd Unit 901 6 Tower 2 Metroplaza 223 Hing Fong Road Kwai Fong N T Hong Kong Tel 852 2401 1200 Fax 852 2401 3431 China Shanghai Microchip Technology Consulting Shanghai Co Ltd Room 701 Bldg B Far East International Plaza No 317 Xian Xia Road Shanghai 200051 Tel 86 21 6275 5700 Fax 86 21 6275 5060 China Shenzhen Microchip Technology Consulting Shanghai Co Ltd Shenzhen Liaison Office Rm 1812 18 F Building A United Plaza No 5022 Binhe Road Futian District Shenzhen 518033 China Tel 86 755 82901380 Fax 86 755 8295 1393 China Qingdao Rm B505A Fullhope Plaza No 12 Hong Kong Central Rd Qingdao 266071 China Tel 86 532 5027355 Fax 86 532 5027205 India Microchip Technology Inc India Liaison Office Marketing Support Division Divyasree Chambers 1 Floor Wing A A3 A4 No 11 O Shaugnessey Road Bangalore 560 025 India Tel 91 80 2290061 Fax 91 80 2290062 Japan Microchip Technology Japan K K Benex S 1 6F
44. ack signal see Section 1 4 6 Shunt Feedback Appendix A Sheet 3 and Section 1 5 3 4 Accessing the Additional non isolated Feedback Signals U23 Microchip TC1412N gate drive IC This contains a low resistance complementary push pull MOSFET pair and input circuitry suitable for interfacing to a wide range of input voltages It has a small footprint allowing it to be located physically close to the transistor allowing a low inductance gate circuit layout Note that the full current drive capability of the TC1412N is not necessarily required as high frequency modulation is not essential for a brake chopper A less expensive TC1410N or TC1411N could be used R60 R62 R67 Q12 C24 C28 These components act to provide a dynamic level shifting circuit to U23 while Q10 switches Inductance of the power tracking between the emitter of Q10 due to the physical board layout means there is a substantial transient voltage up to 2V in this case between the 15V supply star point reference and the emitter of Q10 This simple low cost circuit allows the power supply of U23 to move transiently Q12 provides a level shift to ensure correct assertion of the firing command In applications with fewer constraints on physical layout and or lower switching speed requirements these components may not be needed e Brake Resistor A 50W metal clad 4K7Q resistor mounted to the heat sink is connected to pads J7 and J8 The value of the resistor has be
45. ake Resistor 7 DC Bus mr 2003 Microchip Technology Inc DS70096A page 7 dsPICDEM MC1H 3 Phase High Voltage Power Module FIGURE 1 3 POWER CONNECTIONS Using output connections 6 and 7 the user may connect an external braking resistor The user should consider the maximum and average power to be dissipated at the required DC bus voltage when considering the resistor value They should also consider the peak allowable resistor current of 4A For example if regulating at 400V then a 1000 minimum value should be used which would allow 1 6 kW at most to be dissipated The user may feed in an external DC supply using output connections 5 and 7 This offers the simplest way for a user to bypass the PFC section of the unit In the simplest case all the user needs to do is use an external rectifier and fuse The input current rating when using the auxiliary DC input is 15A RMS The inverter output rating is unchanged Note that if using the auxiliary DC input the internal fuse soft start PFC and ground FAULT protection is bypassed It is up to the user to ensure adequate external protection circuitry is used and incoming DC voltage is correctly regulated 1 2 3 Connecting To The Control Board The system has been designed so that the Microchip dsPICDEM MC1 Motor Control Development Board 02 01648 plugs directly into the 37 pin D Type connector Section 1 7 User Signal Connector Pinout 37 Pin D Type
46. ame time Turning both switches on effectively places a short circuit across the DC bus and is called Shoot Through Shoot Through should be avoided at all costs In order to avoid Shoot Through an appropriate time delay must be inserted between the turn off command to one device and the turn on command to the other device of the same inverter leg This time is called the Dead Time The required Dead Time depends on the switching speeds of the power devices and the timing delays due to the optocouplers and the gate drive circuits Note No hardware Dead Time is included in the design as it is included as a feature of the Motor Control PWM Module of the dsPIC device A minimum Dead Time of 2 us should be used This applies to both turn on and turn off of both devices Writing to the appropriate registers in the dsPIC device DTCON1 and DTCONO2 sets the dead time Refer to the dsPIC30F Family Reference Manual DS70046 for details Although not necessary for correct operation of the system it is common practice to eliminate very narrow firing commands This is because they will have negligible effect on the output waveform but incur additional switching loss It is suggested that a duty cycle that gives transistor on or off times of less than 100 ns be eliminated by rounding the duty cycle up or down as appropriate Note that pulses which are narrower than the dead time set in the Motor Control PWM Module are automatically eliminat
47. ay have a right to sue for relief under that Act Information contained in this publication regarding device applications and the like is intended through suggestion only and may be superseded by updates It is your responsibility to ensure that your application meets with your specifications No representation or warranty is given and no liability is assumed by Microchip Technology Incorporated with respect to the accuracy or use of such information or infringement of patents or other intellectual property rights arising from such use or otherwise Use of Microchip s products as critical components in life support systems is not authorized except with express written approval by Microchip No licenses are conveyed implicitly or otherwise under any intellectual property rights DNV Certification Inc DNV MSC The Netherlands Accredited by the RvA gt 2 LA e 2 7 DINIV ISO 9001 QS 9000 REGISTERED FIRM La Trademarks The Microchip name and logo the Microchip logo dsPIC KEELOQ MPLAB PIC PICmicro PICSTART PRO MATE and PowerSmart are registered trademarks of Microchip Technology Incorporated in the U S A and other countries FilterLab microID MXDEV MXLAB PICMASTER SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U S A Accuron Application Maestro dsPICDEM dsPICDEM net ECONOMONITOR FanSense FlexROM fuzzyLAB In Ci
48. bus is between 350 400V If the user does not wish to use the PFC stage the PFC switches can simply be left off However the PFC inductor and diode will be left in circuit and the input current will remain limited to 5A RMS and 8 9A Peak The user should read Section 1 5 3 3 Bypassing The PFC if this is unacceptable The Brake chopper switch has been designed so that it may be switched up to a maximum frequency of 16 kHz This frequency limit is chosen for power dissipation and low voltage power supply consumption reasons In most braking applications a lower modulation frequency will be used as there is little benefit apart from acoustic noise from modulating at such a high frequency The six inverter switches have been designed so that they may be switched up to a maximum frequency of 20 kHz This frequency limit is chosen for power dissipation and low voltage power supply consumption reasons Unless extremely low output current harmonics or very high bandwidth control is required it is suggested that a 16 kHz carrier frequency be used This offers lower loss while still being inaudible It also has the advantage that the dead time insertion will cause less distortion of the output voltage DS70096A page 10 2003 Microchip Technology Inc Set Up and Operation Given the high side and low side switches of the inverter are connected in series across the DC bus see Figure 2 1 both switches should never be turned on at the s
49. ch has now finished aquiring bsf ADCONO GO bcf GPIO SDO send bit 3 bsf GPIO SCK btfsc BYTE TO SEND 3 bsf GPIO SDO bcf GPIO SCK bcf GPIO SDO send bit 2 bsf GPIO SCK btfsc BYTE TO SEND 2 bsf GPIO SDO bcf GPIO SCK bcf GPIO SDO send bit 1 bsf GPIO SCK btfsc BYTE TO SEND 1 bsf GPIO SDO bcf GPIO SCK bcf GPIO SDO send bit 0 bsf GPIO SCK btfsc BYTE_TO_SEND 0 bsf GPIO SDO bcf GPIO SCK finish conversion btfsc ADCONO GO goto finish conversion movf ADRES W movwf BYTE TO SEND need a min 4us delay before starting next acquire begin to transmit value from channel 2 VAC SENSE bcf GPIO SDO send bit 7 bsf GPIO SCK btfsc BYTE TO SEND 7 bsf GPIO SDO bcf GPIO SCK set up ADC to begin sampling channel 0 movlw 0x41 Fosc 8 A D enabled channel 0 selected movwf ADCONO begin sampling ch0 BUS_SENSE bcf GPIO SDO send bit 6 bsf GPIO SCK btfsc BYTE TO SEND 6 bsf GPIO SDO bef GPIO SCK DS70096A page 50 2003 Microchip Technology Inc Appendix bcf bsf btfsc bsf bcf bcf bs bt bs bc Sc Fh Fh Fh Fh oo ctun Fh Fh Fh Fh Sc bs o Q Fh bcf bsf btfsc bsf bcf bsf bcf bsf btfsc bsf bcf bcf bsf btfsc bsf bcf nop nop nop nop GPIO SDO send bit 5 GPIO SCK BYTE TO SEND 5 GPIO SDO GPIO SCK GPIO SDO send bit 4 GPIO SCK BYTE TO SEND 4 GPIO SDO GPIO SCK GPIO SDO send bit 3 GPIO SCK
50. clamp to ensure R VPH SENSE is protected U31 B A comparator used to provide a simple sensorless position detection scheme for BPM motors Whenever R PH crosses half the DC bus voltage an output transition will occur The R_CROSSING signal is only valid during regions of the electrical cycle where the RED phase output current is zero so that the back EMF of the motor determines the voltage of R VPH Thus the scheme is only suitable for use on BPM motors where 120 degree conduction scheme is used Careful decoding of all three crossing signals and appropriate angle interpolation is required for correct commutation An alternative method for commutation feedback must be used near zero speed where the back EMF is insufficient for the scheme to work R143 R147 These provide a small amount of hysteresis to prevent oscillation of R CROSSING R142 The pull up resistor for the open collector output of the comparator DS70096A page 26 2003 Microchip Technology Inc Set Up and Operation 1 4 8 Firing Signal Isolation and Low Voltage Power Supplies 1 4 8 1 INTRODUCTION The choice of isolation strategy and how the low voltage power supplies are to be derived are two of the major decisions that determine the architecture of a motor drive controller For this design the requirement was for flexibility while maintaining user safety It was essential that the system could work off a wide range of input voltages 1 4 8 2 FIR
51. ctivating the active high ISO RESET line The ISO RESET line is on pin 33 of the 37 pin D type see Section 1 7 User Signal Connector Pinout 37 Pin D Type If using the dsPICDEM MC1 Motor Control Development Board this signal is routed to pin 14 of the 30F6010 dsPIC device which is on Port RE9 The minimum pulse width for the RESET is 2 us The RESET should be done in coordination with the SPI handling routine of the dsPIC device to ensure correct synchronization of the serial interface providing the isolated voltage feedback see Section 1 2 6 2 Isolated Feedback and Section 1 4 7 2 Isolated Voltage Feedback The system is now ready to use 1 242 POWER DOWN SEQUENCE Stop firing all power devices Turn off the incoming AC supply Wait until the red DC bus LED indicator visible through the ventilation holes in the top of the unit has gone out this will take 3 minutes or less Turn off the power supply feeding the control card if required 1 2 5 Power Device Switching Frequencies The PFC stage has been designed for a switching frequency of 50 kHz 5 This offers a good system compromise between cost size and efficiency The modulation frequency affects not only the losses in the power switches and diode but also that in the PFC inductor and snubbing components The user should not deviate from the stated carrier frequency The user should note that a typical regulation level for the DC
52. d to the output protective ground terminal provided Particular care should be taken to mechanically guard such a motor bearing in mind that unexpected behavior is likely to result from the process of code development CAUTION For continued protection against the risk of fire replace the fuse with one of the same type only i e T5A H 250V Time Lag 5A High Breaking Capacity 250V minimum O 2003 Microchip Technology Inc DS70096A page iii dsPICDEM MC4H 3 Phase High Voltage Power Module The system is intended for evaluation and development purposes and should only be operated in a normal laboratory environment as defined by IEC 61010 1 2001 Clean with a dry cloth only Operate flat on a bench do not move during operation and do not block the ventilation holes The system should not be operated without all the supplied covers fully secured in place Screws should not protrude into the unit by more than 5 mm 0 2 type M3 ISO metric The system should not be connected or operated if there is any apparent damage to the unit The unit is designed for installation category Il and to be connected to the AC mains supply via a standard non locking plug As the unit has no mains switch this plug constitutes the means of disconnection from the supply and thus the user must have unobstructed access to this plug during operation DS70096A page iv O 2003 Microchip Technology Inc dsPICDEM MC1H 3 PHASE MICROCH
53. ed Note Theuser should verify that all PWM frequencies and dead time settings are correct using an oscilloscope before connecting the control signals to the power module In order to provide an economic design so called bootstrap power supplies are used for the high side inverter switches see Section 1 4 3 3 Gate Drive for details As the charging path for these is only made when the corresponding low side switch or diode conducts this places some minor restrictions on modulation These are as follows 1 When the power module is first energized after a period of time where no modulation has taken place all low side switches should be turned on for 2 3 us This ensures the bootstrap supplies are primed This can be simply done by using the output override facility in the dsPIC Motor Control PWM module by setting the correct bits in the OVDCON register Care should be taken to ensure a shoot through does not accidentally occur The possibility of a shoot through fault will be minimized if the dsPIC PWM module is operated in the complementary Output mode module default 2 If the user is continuously modulating all the low side switches as part of their PWM strategy the priming step is not strictly necessary as it will happen automatically There will however be a delay of variable duration before the high side switches actually fire The delay will depend on the particular operating circumstances and whether it is acceptab
54. educed the DC bus voltage to a safe level The red LED bus voltage indicator visible through the top ventilation holes should be out Verify with a voltmeter that discharge has taken place by checking the potential between the and DC terminals of the 7 pin output connector before proceeding The voltage should be less than 10V The system is now safe to work on Remove all cables from the system Remove the screws fixing the lid to the chassis and heat sink on the top and bottom Slide the lid forwards while holding the unit by the heat sink 1 5 3 Changing Current Feedback and Trip Scaling Provision has been made to change the current feedback scaling of both the isolated Hall effect transducers and the inverter leg and bus shunts As the trip levels are set at a fixed voltage changing the feedback scaling also changes the trip levels Changing the scaling is accomplished in the following way Follow the procedure given in Section 1 5 2 Accessing The System for accessing the unit Changing the inverter leg shunt sensing between unipolar and bipolar is accomplished with LK4 LK4 is located directly under the Danger High Voltage label on the PCB as shown in Section 9 Table 1 6 shows the settings TABLE 1 6 SHUNT FEEDBACK POLARITY SELECTION LK 4 Setting Feedback Range 1 2 Bipolar 2 3 Unipolar DS70096A page 30 2003 Microchip Technology Inc Set Up and Operation
55. en chosen to allow a maximum dissipation of 40W If the user wishes to be able to dissipate more power then an external resistor can be connected to pins 6 and 7 of the 7 pin output connector This will operate in parallel with the internal resistor If the user wishes to change the value of the internal resistor or disconnect it they should read Section 1 5 3 2 Modifying or Removing the Internal Braking Resistor 1 4 5 Isolated Current Feedback Appendix A Sheets 1 and 2 In order to provide isolated current feedback Hall effect closed loop DC current transducers LEM LTS 6 NP devices have been installed These devices have the following characteristics Single 5V supply with 2 5V nominal representing OA Bipolar current sensing with 19 2A given by 4 5V and 0 5V respectively with a single turn through the transducer e 2200 kHz bandwidth 3 kV AC isolation A detailed device data sheet can be obtained from www lem com Two such devices U3 and U4 are installed in series with the output connections of phases R and Y These are configured to have 4 turns through the device with LK 15 and 18 installed and an additional turn formed by the internal output leads This gives a maximum sensed current of 4 8A and a gain of 2 4A V Note that a third device is not required as the sum of the output line currents must always be zero due to symmetry The one exception to this is during a ground FAULT condition that is detected elsewhere
56. es how to use the Microchip dsPICDEM MC1H High Voltage 3 Phase Power Module The manual layout is as follows Chapter 1 Set Up and Operation Describes what the product is what makes it a desirable development tool how to install it and the basic features of the interface e Worldwide Sales and Service Lists Microchip sales and service locations and telephone numbers worldwide Documentation Updates All documentation becomes dated and this user s guide is no exception Since MPLAB IDE MPLAB C1X and other Microchip tools are constantly evolving to meet customer needs some actual dialogs and or tool descriptions may differ from those in this document Please refer to our web site to obtain the latest documentation available Documentation Numbering Conventions Documents are numbered with a DS number The number is located on the bottom of each page in front of the page number The numbering convention for the DS Number is DSXXXXXA where XXXXX A The revision level of the document The document number O 2003 Microchip Technology Inc DS70096A page 1 dsPICDEM MC4H 3 Phase High Voltage Power Module WARRANTY REGISTRATION Please complete the enclosed Warranty Registration Card and mail it promptly Sending in your Warranty Registration Card entitles you to receive new product updates Interim software releases are available at the Microchip web site RECOMMENDED READING This user s guide desc
57. etween the AC input voltage and the DC bus voltage i e the larger the average boost ratio This is because the average switch duty cycle increases the larger the boost ratio and therefore the switch conduction loss increases Furthermore the switching loss also increases slightly with boost ratio O 2003 Microchip Technology Inc DS70096A page 15 dsPICDEM MC4H 3 Phase High Voltage Power Module For a fixed DC bus voltage the PFC diode is more heavily thermally loaded the higher the AC input voltage This is simply due to the increase in power through put with higher AC input voltage due to the fixed input current For a given AC input voltage operation at lower DC bus voltage will also load the diode more heavily thermally as the average current increases for the constant power throughput Note The over current trip levels are set above the peak of the rated output This is to allow for current ripple modest amounts of acceleration and to prevent nuisance trips The user should avoid operating the system beyond the peak rated output of 7 1A RMS continuously or controlling the input waveshape to be anything other than the correct half sinusoid Operation of the system just beneath the over current trip levels may affect long term reliability of the switches and should be avoided 1 3 3 Input Current Limits when Not Using the Active PFC If the user does not wish to use the PFC stage the PFC switch can simply be left off
58. for the clock and data lines R149 R150 Series resistors that help to set the current through the optocoupler emitters They are sized to allow a minimum of 1 8 mA to flow C64 C70 Speed up capacitors to help reduce the effect of the optocoupler s emitter capacitance at high data rates R170 R171 Pull up resistors for the open collector outputs of U16 and U17 1 4 7 8 INVERTER OUTPUT VOLTAGE FEEDBACK AND SENSORLESS DETECTION Knowledge of the actual inverter output voltage is useful for two different uses The first is for accurately compensating for output voltage errors due to dead time and power device voltage drops This can be especially important for high current low voltage systems with high PWM frequencies and high performance requirements The second use is for back EMF sensing for sensorless position detection schemes for Brushless Permanent Magnet BPM and other types of motors The hardware for providing this is now discussed with reference to the RED phase The other two phases have identical circuits R20 R21 and R144 A resistor divider chain with scaling the same as the DC voltage feedback The same scaling is required in order that the back EMF crossing detection works correctly The scaling is such that the maximum expected output voltage will give 4 5V C61 This provides filtering of the inverter output voltage in combination with R20 R21 and R144 D41 This provides a
59. gh thermal loading because one of the inverter switches has the peak worst case conduction and switching loss continuously Note that as far as the power devices are concerned operation at output frequencies of less than approximately 10 Hz are equivalent to stall as far as peak device temperature is concerned because of low thermal capacitance In a practical application this condition of low output frequency stall and high duty cycle is unlikely to happen With a motor correctly matched to the DC bus voltage the switch duty cycle at stall will be approximately 5096 thus significantly reducing the conduction loss in a particular switch The complementary diode of the inverter phase will also conduct for approximately 5096 thus spreading the conduction loss between two different power device packages This in turn leads to a substantial reduction in device temperature CERTE EAR E E J a n DS70096A page 14 2003 Microchip Technology Inc Set Up and Operation The user should note that the over current trip levels are set above the peak of the rated output This is to allow modest amounts of acceleration deceleration and to prevent nuisance trips The user should avoid operating the system beyond the peak output of 3 5A continuously Operation of the system just beneath the over current trip levels at the worst case stall condition discussed above may affect long term reliability of the
60. he effect is likely to be less severe as a DC over voltage will occur tripping out both the armature and field supply assuming the field is not supplied separately For this reason if using a separately excited DC motor it is recommended that both the field and the armature are supplied from the unit 1 3 CURRENT AND POWER LIMITATIONS The maximum power and current capability of the system is dictated by the allowable temperature rise of the different components Establishing maximum limits is not simple given the host of different ways the user may use the system The voltage and the nature of the electrical load used both affects the dissipation that occurs In determining the allowable limits for the power semiconductors the following assumptions have been made Heat sink is at 70 C worst case over temperature trip point Thermal resistance of the insulating thermal pad is 4 C W Note that the maximum power of the system will always be the lower value due to the AC input stage or the inverter output stage 1 3 1 Inverter Output Current Limits The inverter is capable of providing the full rated output of 2 5 A RMS within the entire operating range voltage temperature and at up to 20 kHz PWM carrier frequency of the system This includes being continuously stalled at such an electrical angle that one of the motor phases is at the peak of the rated output 3 5A at just less than 100 duty cycle This is a condition that causes hi
61. inductor marked as L2 2 near the left hand DC bus capacitor C4 This can be done from the top of the PCB Solder the L2 wire into pad J4 ensuring that the maximum length of lead protruding below the PCB is 4 mm If required replace the input fuse with a 6 7A part of the same type Time Lag High Breaking Capacity and 250V or greater voltage rating Once the modification is complete install the lid ensuring all the screws are replaced Note that the maximum continuous limit on input current increases to 6A RMS limited by the loss in the PFC inductor 2003 Microchip Technology Inc DS70096A page 33 dsPICDEM MC4H 3 Phase High Voltage Power Module Removing the PFC inductor from the circuit 1 Follow the procedure given in Section 1 5 2 Accessing The System for accessing the unit De solder L1 This can be done from the top of the PCB Solder a wire between J4 and J6 The wire size should be 1 mm 18 AWG with a minimum voltage rating of 600V and suitable for operation up to 105 C Note that the wire should be no longer than 75 mm 3 in length and should be cropped to ensure that the maximum length of lead protruding below the PCB is 4 mm If required change the current scaling of U2 as given in Section 1 5 3 Changing Current Feedback and Trip Scaling If required replace the input fuse with a 7 8A part of the same type Time Lag High Breaking Capacity and 250V
62. ing earth ground In order to make the links for the non isolated signals it is recommended that two 0 3 pitch 14 pin DIL resistor packages be used These should be of the straight through type with 7 independent resistors The suggested value is 3300 as this will provide some ESD protection without too high of a source impedance being introduced Note that LK28 has no circuit connections and is provided to allow the second DIL resistor package to be installed If the user decides to fit links or individual resistors these should be installed so that not more than 4 mm of lead protrude beneath the PCB Note that all signals to and from the system are now referenced to the DC bus that is at earth ground potential The isolation transformer is providing the safety isolation The digital OV of the control card is permanently connected to the enclosure chassis and is therefore also referenced to ground Once the modification is complete install the lid ensuring all the screws are replaced DS70096A page 34 2003 Microchip Technology Inc Set Up and Operation 15 35 OTHER MODIFICATIONS Clearly there are many other modifications that an experienced engineer could make to the system These could include Changing the inverter power devices for lower voltage devices e g IRF644 250V MOSFETs if operation at low input voltages only is required Changing the DC bus capacitors for higher capacitance lower voltage c
63. le or not will depend on the particular application 3 In extreme circumstances it is possible that the high side bootstrap supply will discharge while the system is running This will not happen for typical sinusoidal modulation schemes provided an inductive load e g a motor is connected If a bootstrap supply collapses an under voltage lockout will automatically occur to protect the high side switch entering the linear region of operation The high side switch is turned off whatever the command The lockout is automatically cleared when the bootstrap supply is restored and the next turn on edge occurs If necessary the user should periodically apply a refresh pulse to the low side switch in a similar manner to that described for priming above O 2003 Microchip Technology Inc DS70096A page 11 dsPICDEM MC1H 3 Phase High Voltage Power Module 1 2 6 Power Module Feedback Signals 1 2 6 1 INTRODUCTION The power module may be operated in two distinct ways with respect to signal isolation This effects which of the feedback signals are available All feedback signals are preconditioned and scaled within the power module Which particular set of feedback signals the user requires will change depending on the application Typically industrial applications tend to use isolated signals for both safety noise and performance reasons More cost sensitive applications and especially those that have little or no user input tend to run the cont
64. lly conductive heat sink compound e g Dow Corning 340 to the back of the resistor Fit the resistor to the heat sink and solder the wires into J7 and J8 Ensure the leads are cropped so that the maximum length of lead protruding below the PCB is 4 mm Once the modification is complete install the lid ensuring all the screws are replaced Note that if the user fits a lower value of internal resistor to allow higher transient dissipation then the user s software must ensure adequate thermal protection for the resistor Failure to do so can cause the resistor to rupture Consult the manufacturers data sheet carefully 15 33 BYPASSING THE PFC If the user does not require the use of the active Power Factor Correction all the user needs to do is not fire the PFC switch The system will still benefit from the PFC inductor acting to smooth the input current when the rectifier is charging the DC bus capacitors However the PFC diode will remain in circuit This will incur additional unnecessary loss Provision has therefore been made to bypass the PFC in two different ways Alternatively the user could feed in an external DC supply using the auxiliary DC input see Section 1 2 2 Making Power Connections The procedures for bypassing the PFC is described below Keeping the PFC inductor in circuit Follow the procedure given in Section 1 5 2 Accessing The System for accessing the unit De solder the wire of the large toroidal
65. nd 7 1 4 7 1 INTRODUCTION Provision has been made for three different types of voltage feedback e DC bus voltage feedback This is required for regulation via the brake chopper or the active Power Factor Correction PFC circuit It is also used to compensate for variations in the inverter output voltages that occur due to any ripple on the DC bus and as a FAULT trip Rectified mains voltage feedback VAC This is required for synchronization and shaping of the input current by the active PFC circuit e e Inverter output voltage feedback As well as providing the feedback signal a comparator circuit is included for sensorless operation The first two of these signals are available as isolated signals whereas the inverter output voltages are only available when the system is used in the non isolated manner see Section 1 2 6 3 Non isolated Feedback and Section 1 5 3 4 Accessing the Additional non isolated Feedback Signals DS70096A page 24 2003 Microchip Technology Inc Set Up and Operation 1 4 7 2 ISOLATED VOLTAGE FEEDBACK There are many different ways that the two isolated voltage feedback signals can be provided Clearly the DC level must be correctly maintained while still giving sufficient bandwidth The bandwidth is especially important for the VAC signal in order to ensure low harmonics are produced by the active PFC Power supply consumption should also be as low as possible
66. odulation of the switches When a star or delta connected three phase motor is used the electrical symmetry can be exploited to provide bi directional current and voltage with just three such legs In this way both motoring and generating braking operation can be used in either direction of rotation commonly called 4 Quadrant control There is no reason why the user can not use two of the legs in an H bridge configuration for control of DC motors or other single phase applications requiring bi directional current and voltage Even a single leg could be used with just the low side switch controlled for a simple unidirectional current application e g field control of a separately excited DC motor The detailed description of one leg red phase is given below The other legs are identical in function 1 4 3 2 POWER DEVICES Q3 Q4 600V N Channel IGBT transistors with co packaged anti parallel 600V diodes They are packaged in the industry standard TO220 As the tabs of the devices are not isolated a thermally conductive insulator is used The IGBTs are optimized for switching at frequencies up to 20 kHz while having improved tolerance to FAULT conditions at the slight expense of conduction loss The diodes are of the soft recovery type for reduced RF emissions The tracking between the devices and to the DC bus is designed to minimize the inductance that causes transient over undershoots R4 A 3W 25 mQ shunt resis
67. odule NOTES DS70096A page 38 O 2003 Microchip Technology Inc LL YN lt I A e I v O H LL e n Y Lo HIGH VOLTAGE POWER MODULE 8 401 133HS GO ZA NOISYJA 0 0SSdS ON ONIMVUQ einpow Jewog 3BDIJOA YIH spud 01 U09 1010 diu20J9 WN 3SN3S Sh8 Zen JAAN C0 LY910 90 sng7o0 MOT 1NnHS JAVY gt 00 dIHOOUYOIN 28 829 29 31111 SS A cr H9IH INGHS diva e E SUOIINIO J9MO JD UJ ut dll HhIos di S KOPA ween LLY E A7 H E E o 6 AAA 100 ui N S y 994 Fal 2 s E p sen 28 aut AVG Sh Se S n 1 ELCH c S8 e pmi E OS BSS Ss OS sng 20A ASH IrCUI yo sr 198 2 uid ur au Aq paooiday IN DS70096A page 39 H E 60 Sn8 20 Yani e NOLLO3NNO2 H18V3 SISSVHO Q SE e z 9 us gir vr MOO 4 ALY 878 is lt 8 S 022 gt gt Hi 3 lt Pleo us e e rO DIEN y i d 678 SSA SSA E Au Luy wo Ou 100 ON E i om noi wo 3 100 38 J i 2 La L aaa 00 3 Scu S wz noge nose noce Did e 0 ls a kda aor anoi 300 7 o 9 eo w not PO A5 li enn Q o zza H 89 EA N ES L ka a lt
68. ogy Inc Preface DEVELOPMENT SYSTEMS CUSTOMER NOTIFICATION SERVICE Microchip started the customer notification service to help our customers keep current on Microchip products with the least amount of effort Once you subscribe you will receive e mail notification whenever we change update revise or have errata related to your specified product family or development tool Go to the Microchip web site at http www microchip com and click on Customer Change Notification Follow the instructions to register The Development Systems product group categories are Compilers Emulators e In Circuit Debuggers MPLAB Development Systems Programmers Here is a description of these categories Compilers The latest information on Microchip C compilers and other language tools These include the MPLAB C17 MPLAB C18 and MPLAB C30 C compilers MPASM and MPLAB ASM30 assemblers MPLINK and MPLAB LINK30 object linkers MPLIB and MPLAB LIB30 object librarians Emulators The latest information on Microchip in circuit emulators This includes the MPLAB ICE 2000 and MPLAB ICE 4000 In Circuit Debuggers The latest information on Microchip in circuit debuggers These include the MPLAB ICD and MPLAB ICD 2 MPLAB Development Systems The latest information on Microchip MPLAB IDE the Windows Integrated Development Environment for development systems tools This list is focused on the MPLAB IDE MPLAB S
69. omponents No guarantee or liability can be accepted for any modifications that the user makes to the system If the user removes the PCB from the enclosure chassis they should ensure that the power device clamping force and the insulation is unaltered when the PCB is re installed oy 2003 Microchip Technology Inc DS70096A page 35 dsPICDEM MC1H 3 Phase High Voltage Power Module 1 6 TEST POINTS The following test points are all located on the topside of the PCB See Appendix A for references to the net names on the schematics bed Signal Function Net Name TP 1 LIVE PFC Switch Firing Command Active Low PFC FIRE TP2 LIVE Red Top Switch Firing Command FIRE R TOP TP 3 LIVE Red Bottom Switch Firing Command FIRE R BOT TP 4 LIVE Yellow Top Switch Firing Command FIRE Y TOP TP 5 LIVE Yellow Bottom Switch Firing Command FIRE Y BOT TP6 LIVE Blue Top Switch Firing Command FIRE B TOP TP7 LIVE Blue Bottom Switch Firing Command FIRE B BOT TP8 LIVE Fault Indication FAULT TP9 LIVE Brake Chopper Firing Command Active Low BRAKE FIRE TP 10 LIVE Serial Data from PIC12C671 for voltage feedback LIVE DATA TP 11 LIVE Serial Clock from PIC12C671 for voltage feedback LIVE SCLK TP 12 LIVE Divided down voltage of half DC bus HALF BUS SENSE TP 13 LIVE High reference used for FAULT trips HIGH REF TP 14 LIVE Low reference used for FAULT trips LOW REF TP 15 LIVE Fault Reset and P
70. ontrol The operating range and the quality of control will dictate whether a bus shunt alone can be used Clearly it is the cheapest of all schemes to implement The current that the shunt has flowing in it at any given time depends on the state of all three inverter legs It should be recalled that having both switches in the same leg on at the same time is not allowed The top switch being off Top Fire 0 assumes a bottom switch is on It does not matter whether the current actually flows in the switch or the anti parallel diode The result depends only on the magnitude and direction of the output currents see Table 1 5 mF 2003 Microchip Technology Inc DS70096A page 23 dsPICDEM MC4H 3 Phase High Voltage Power Module TABLE 1 5 DC BUS SHUNT RESISTOR FEEDBACK Fire R Top Phase Y Top Phase B Top DC Bus Shunt 0 0 0 0 0 0 1 IB 0 1 0 HY 0 1 1 IR 1 0 0 IR 1 0 1 IY 1 1 0 IB 1 1 1 0 From this table it is clear that bipolar sensing requires with the same scaling as that used for the inverter leg shunts It can be seen that for the 000 and 111 conditions which corresponds to zero output phase voltage no information is available This can cause considerable problems if operation at low output voltages is required when using sinusoidal modulation Instead of actually physically implementing the bus shunt in this design the signal has been derived as the sum of the three inverte
71. orting out R85 and R89 Note that both links must be used together for correct operation LK4 Provision is made for either bipolar or unipolar sensing by changing this link It changes the non inverting input reference point between 2 5V and OV Bipolar sensing is required for applications using sinusoidal modulation whereas unipolar sensing is sufficient for other applications Other points to note No common mode filtering has been used as the amplifier s inherent common mode rejection is sufficient and it requires tight tolerance components to be effective Note that the output of the op amp is not glitch free during switching transitions but tracks the current rapidly It is assumed that suitable synchronization of the sampling of the output is used to reject the glitches The self inductance of the shunts approx 10nH causes an additional voltage to be produced proportional to the rate of change of current For typical motors this additional voltage is negligible as the inductance is high enough to ensure a low rate of change of current If a low inductance load is used the effect of the additional voltage will have to be compensated for in the user s software 1 4 6 5 DC BUS SHUNT RESISTOR FEEDBACK In addition to the three inverter leg shunts provision has been made to monitor the current in the DC bus In many applications the information contained in this signal alone is sufficient to provide the required closed loop c
72. ose users wishing to use the system without the PFC or at lower voltages Figure 1 6 gives the peak peak DC bus voltage ripple for three different conditions O 50 0 qu 000 O 0 H m DD O M DS70096A page 16 O 2003 Microchip Technology Inc Set Up and Operation FIGURE 1 6 DC BUS VOLTAGE RIPPLE 30 N al PFC Active 208V AC 50 Hz Input 350V Bus m PFC Choke in Circuit 208V AC 50Hz PFC Choke in Circuit 110V AC 60Hz N e o Pk Pk Ripple Volts a al o 0 200 400 600 800 1000 Output Power Watts Note that if operating without the PFC inductor in circuit that the DC bus voltage ripple is similar in magnitude to that shown above but the average DC bus voltage is higher for the same power 1 3 5 Brake Chopper Output Current Limits The brake chopper switch and diode are capable of providing the full rated output of 4A within the entire operating range voltage temperature and at up to 16 kHz modulation frequency of the system The brake chopper diode has been oversized from that usually required due to the inductance of an external braking resistor and cables so that the brake chopper is more general purpose Note Theuser should note that the over current trip levels are set above the peak of the rated output This is to prevent nuisance trips The user should avoid operating the system beyond the peak outpu
73. ower Limitations and Section 1 4 Detailed Description of Operation carefully before using the system FIGURE 1 1 POWER MODULE WITH ATTACHED DEVELOPMENT BOARD SOLD SEPARATELY 2003 Microchip Technology Inc DS70096A page 5 dsPICDEM MC1H 3 Phase High Voltage Power Module MC1H 3 PHASE HIGH VOLTAGE POWER MODULE BLOCK DIAGRAM FIGURE 1 2 Om From Control Board o E Control Board y eqp 4 juaJino eseud pajejos A Y Y yoeqp d juaJing 1ndu Oq Pajejos p S Ppajejos uonejosiojdo eAug ejes uonejosiondo yoeqpee4 apis au o 9 ae o E a queuing eyes now 9BeioA sna 20 UOJMS exeug CES BEIS EWEN jueun2 sng Sq eDeyoA sng 20 eA WOUND OMS A seddoy9 exeig 10798109 i 10 08 4 18MOd e e x E x e4neN Y VI Ki O 8 9 H ES R f D 1 D la Jr RS ES OV AS9Z 0 e O o e e o e e UE e O 2003 Microchip Technology Inc DS70096A page 6 Set Up and Operation 1 2 USING THE MOTOR CONTROL 3 PHASE HIGH POWER MODULE 1 2 1 Introduction The user should be aware of the operating procedures outlined below and ensure that they are followed Failure to do so may result in damage
74. pply circuitry on the live side is described below U18 An isolating 3 kV rated 1W unregulated DC DC converter with 5V input and 15V nominal output The 15V supply is used for the gate drive of the power devices and the comparators on the live side of the isolation barrier L4 and C83 A filter to reduce the reflected ripple on the 5V supply from the control board caused by the DC DC converter L3 and C77 A filter to reduce the magnitude of the ripple on the live 15V supply U5 A 5V linear regulator for the live control circuit supplies D4 A 1A diode to protect U5 against reverse bias during power down R61 A OQ resistor linking the low voltage power supply star point to the DC bus m 2003 Microchip Technology Inc DS70096A page 27 dsPICDEM MC1H 3 Phase High Voltage Power Module 1 4 9 FAULT Protection Appendix A Sheets 4 5 and 6 1 4 9 1 INTRODUCTION Given the development nature of the system robust independent FAULT protection is provided on the power board rather than relying on software intervention Five different fault categories are used to indicate a FAULT to the user Four of the fault categories are detected on the live side All FAULTS are latched and automatically disable all firing commands In a commercial application using the dsPIC device much of the hardware described below may be eliminated In particular the latches are not required as the Output Compare and Motor Control PWM
75. r S au Sei INNHSTA EIER 46 694 K ya 13S 4407 LNQHS o 3A A Ln lt 3448 2 9x1 3 u09s uss Ze ES ACL 265451 HOIHT LNNHST8 ios P 434 SAO o 1353307 INAHS DA ven su n q 629 E 3448 DER yee 328 INMHST8 PTS RSE DECH Her AAA lt MOT 1NNHST8 894 v DECH ven 664 C 34 8 EN Sz x 8096 yee 6x7 INNHST8 Cen ven C amu dIHIO JOIN X HOIHTLNNHST A EEN MOT INDHS lt uoi ANnHST Y MOT 1NnHS N DS70096A page 41 O 2003 Microchip Technology Inc dsPICDEM MC4H 3 Phase High Voltage Power Module A JAJA CO LV9LO 0 dIHOOYOIN 8 40 133HS GO ZA 10 0SSdS NOIS33A ON ONIMVUG einpoWw 4ewogd 23BDIOA ubiH VOOJH LON A 4089 0073 espug JOJJUOS 10 0W dIY90J9IW A JILL S 914378399013 33VU8 j387HOIH suol1injo J9MO AD Uu ME d d i 1 S d 1 S JA 3 S WLLEWT ANNHS 3AVY8 ot ZN ace M A VOO9HYLON E A 4 ao ISF ES VOO9HYLON A 30SL 4 vou o Bry m 301 NES lt 4387 H9IH D lt lt asnas7sna LAr Svid M gea ET E Y ES AS v 44022 AG geo AG oly neeem 7 A 1NNHS sna n Zoka S PO aao e lt WL e Jdozz sea NW 463 4u0 gt lt 240001 y m r g wo el NG ENT o N A A mun Lea 7 M 4 INVI A O cia sz goly
76. r leg shunts In this way power circuit layout was not compromised In a commercial application it is normal to implement all three leg shunts or the bus shunt but not both schemes The summing amplifier circuit used can be seen on Appendix A Sheet 3 1 4 6 4 BRAKE SHUNT RESISTOR FEEDBACK Knowledge of the brake resistor current magnitude is not required for control of the DC bus voltage with a brake chopper Only feedback of the DC bus magnitude is required Knowledge of the brake resistor value and the applied PWM can be used to determine peak and average current flowing for thermal protection of both the resistor and the power devices However knowledge of the brake chopper current is useful for protection of the switch should a wiring fault occur or the resistor fail Although a fuse could be used it is often difficult to design and expensive requiring very fast acting types In this instance instead of a fuse the switch current is monitored by a shunt between the emitter and the DC bus in exactly the same way as used for the inverter This is used for an over current trip and is also made available as an optional feedback signal Thus the brake chopper can also be used as either an open or closed loop low side chopper for single quadrant applications The differential amplifier circuit is shown on Appendix A Sheet 3 See Section 1 4 6 1 Introduction for a more detailed explanation 1 4 7 Voltage Feedback Appendix A Sheets 1 6 a
77. rcuit Serial Programming ICSP ICEPIC microPort Migratable Memory MPASM MPLIB MPLINK MPSIM PICC PICkit PICDEM PICDEM net PowerCal Powerlnfo PowerMate PowerTool rfLAB rfPIC Select Mode SmartSensor SmartShunt SmartTel and Total Endurance are trademarks of Microchip Technology Incorporated in the U S A and other countries Serialized Quick Turn Programming SQTP is a service mark of Microchip Technology Incorporated in the U S A All other trademarks mentioned herein are property of their respective companies O 2003 Microchip Technology Incorporated Printed in the U S A All Rights Reserved e Printed on recycled paper Microchip received QS 9000 quality system certification for its worldwide headquarters design and wafer fabrication facilities in Chandler and Tempe Arizona in July 1999 and Mountain View California in March 2002 The Company s quality system processes and procedures are QS 9000 compliant for its PICmicro 8 bit MCUs KEELOQ code hopping devices Serial EEPROMs microperipherals non volatile memory and analog products In addition Microchip s quality system for the design and manufacture of development systems is ISO 9001 certified DS70096A page ii O 2003 Microchip Technology Inc dsPICDEM MC1H 3 PHASE MICROCHIP HIGH VOLTAGE POWER MODULE Safety Notice The safety notices and operating instructions provided should be adhered to to avoid a safety hazard If in any
78. ribes how to use the dsPICDEM MC1H 3 Phase High Voltage Power Module The data sheets contain current information on programming the specific microcontroller devices THE MICROCHIP WEB SITE Microchip provides online support on the Microchip World Wide Web WWW site The web site is used by Microchip as a means to make files and information easily available to customers To view the site you must have access to the Internet and a web browser such as Netscape Navigator or Microsoft Internet Explorer The Microchip web site is available by using your favorite Internet browser to attach to http www microchip com The web site provides a variety of services Users may download files for the latest development tools data sheets application notes user s guides articles and sample programs A variety of information specific to the business of Microchip is also available including listings of Microchip sales offices distributors and factory representatives Technical Support Frequently Asked Questions FAQ Online Discussion Groups Conferences for products Development Systems technical information and more Microchip Consultant Program Member Listing Links to other useful web sites related to Microchip products Engineer s Toolbox Design Tips Device Errata Other available information Latest Microchip Press Releases Listing of seminars and events Job Postings DS70096A page 2 2003 Microchip Technol
79. rol electronics live and use non isolated feedback signals 1 2 6 2 ISOLATED FEEDBACK Table 1 2 gives the scaling of the isolated feedback signals as the system is delivered TABLE 1 2 ISOLATED SCALING Feedback Signal Scaling Inverter Output R and Y Hall Current Sensor 2 4 A V with 2 5V 0A DC Input Hall Current Sensor 4 8 A V with 2 5V OA DC Bus Voltage via SPI Channel 230 410V 1LSB 1 78V Rectified AC Voltage VAC via SPI Channel 230 369V 1LSB 1 60V 1 2 6 8 NON ISOLATED FEEDBACK As the system is delivered access is not given to the non isolated feedback signals to ensure user safety If an experienced user wishes to access these signals they should read Section 1 4 Detailed Description of Operation along with Section 1 5 3 4 Accessing the Additional non isolated Feedback Signals Note that once the isolation barrier is bridged all signals can no longer be considered to be isolated from the power circuit When operating in the non isolated configuration the Hall current sensors and SPI voltage feedback signals are also available The scaling for the signals as the system is delivered is given below For details of changing the scaling see Section 1 5 3 Changing Current Feedback and Trip Scaling TABLE 1 3 NON ISOLATED SCALING Feedback Signal Scaling R Y B Inverter Leg Shunts 2 4 A V with 2 5V OA DC Bus Shunt 2 38 A V with 2 5V
80. s a low resistance complementary push pull MOSFET pair and input circuitry suitable for interfacing to a wide range of input voltages It is an ideal choice for this application allowing up to 2A of peak gate drive current to switch Q1 and Q2 rapidly and therefore achieve low switching loss It also has a small footprint allowing it to be located physically close to the transistors allowing a low inductance gate circuit layout DS70096A page 18 2003 Microchip Technology Inc Set Up and Operation C20 C21 Q11 R45 R46 R52 These components act to provide a dynamic level shifting circuit to U19 while Q1 and Q2 switch Inductance of the power tracking between the sources of Q1 and Q2 due to the physical board layout means there is a substantial transient voltage up to 5V in this case between the 15V supply point reference at R61 and the sources of Q1 and Q2 This simple low cost circuit allows the power supply of U19 to move transiently Q11 provides a level shift to ensure correct assertion of the firing command In applications with fewer constraints on physical layout and or lower switching speed requirements these components may not be needed 1 4 3 Phase Inverter Appendix A Sheet 2 1 4 8 4 INTRODUCTION The 3 phase inverter has three identical circuits shown as R RED Y YELLOW and B BLUE These are often referred to as inverter legs They invert the DC bus back to a variable AC output waveform by appropriate m
81. ses it is suggested that the changes be made from the top of the board If new component legs are inserted these should be cropped to ensure that the maximum length of lead protruding below the PCB is 4 mm Once the modification is complete install the lid ensuring all the screws are replaced CE t DS70096A page 32 O 2003 Microchip Technology Inc Set Up and Operation 1 5 3 2 MODIFYING OR REMOVING THE INTERNAL BRAKING RESISTOR The type of braking resistor installed on the heat sink allows a maximum continuous dissipation of 50W but can tolerate many times this power level for short periods The value installed as standard only allows a maximum dissipation of 35W owing to its high resistance If the user wishes to change the resistor to a lower value or remove the resistor completely as they are using an external resistor then they should follow the procedure given below Follow the procedure given in Section 1 5 2 Accessing The System for accessing the unit De solder or cut the wires to J7 and J8 This can be done from the top of the PCB Undo the screws attaching the resistor to the heat sink and remove the resistor and its wiring If not fitting a new resistor proceed to the last step Make up a wiring assembly for the new resistor with similar lead lengths and the terminals protected with heat shrink sleeving Ensure the wire has sufficient current and voltage rating 600V Apply a thin even coating of therma
82. t Yes 16 Yellow Phase Hall Current Sensor Feedback Y_HALL Output Yes 17 PFC Hall Current Sensor Feedback PFC_HALL Output Yes 18 Digital GND from control PCB ISO GND Input Yes 19 Digital 5V from control PCB 2 ISO_ 5V Input Yes 20 Blue Phase Shunt Current Feedback B SHUNT Output No if LK19 installed 21 Red Phase Shunt Current Feedback R_SHUNT Output No if LK21 installed 22 Brake Chopper Switch Shunt Current Feedback BRAKE_SHUNT Output No if LK23 installed 23 Blue Phase Voltage Feedback B_VPH_SENSE Output No if LK24 installed 24 Red Phase Voltage Feedback R_VPH_SENSE Output No If LK26 installed 25 Yellow Phase Back EMF crossing Y CROSSING Output No if LK28 installed 26 DC Bus Voltage Feedback BUS SENSE Output No if LK30 installed 27 Analog GND from control PCB ISO AGND Input Yes 28 Brake Chopper Switch Firing Command CMD BRAKE Input Yes 29 Blue Phase Bottom Switch Firing Command CMD B BOT Input Yes 30 Yellow Phase Bottom Switch Firing Command CMD Y BOT Input Yes 31 Red Phase Bottom Switch Firing Command CMD R BOT Input Yes 32 Active Low Serial Data ISO DATA Output Yes 33 Fault Reset Command ISO RESET Input Yes 34 Not Used 35 Red Phase Hall Current Sensor Feedback R HALL Output Yes 36 Digital GND from control PCB ISO GND Input Yes 37 Digital 5V from control PCB 2 ISO_ 5V Input Yes 2003 Microchip Technology Inc DS70096A page 37 dsPICDEM MC1H 3 Phase High Voltage Power M
83. t of 4A continuously Operation ofthe system just beneath the over current trip of 4 9A may affect long term reliability of the brake chopper switch and should be avoided The value of the brake chopper resistor should be chosen to ensure no more than 4A can flow even at the peak DC bus voltage 1 4 DETAILED DESCRIPTION OF OPERATION 1 4 1 AC Supply Input Stage Appendix A Sheet 1 The AC supply input stage of the board consists of the following components F1 1 25 x 0 25 5A 250 VAC high rupture fuse Note only replace with part of the same rating C8 X2 class film capacitor to aid in the suppression of AC supply transients R11 A 1W high voltage resistor which acts to discharge C8 C9 C10 Y class film capacitors to aid in the suppression of AC supply transients and to also provide a low impedance return path for any currents that flows from the power device tabs to the heat sink and enclosure due to capacitive coupling BR1 A single phase bridge rectifier to convert the incoming AC into DC suitable for input to the power conditioning stage V1 A metal oxide varistor located across the incoming supply lines to suppress high energy transients O 2003 Microchip Technology Inc DS70096A page 17 dsPICDEM MC1H 3 Phase High Voltage Power Module 1 4 2 Input Power Stage Appendix A Sheet 1 1 4 2 1 SOFT START PROTECTION NTC1 A resistor with a negative temperature coefficient that acts
84. the inverter leg shunts and the bus current signal derived from them see Section 1 4 6 2 Inverter Leg Shunt Resistor Feedback and Section 1 4 6 3 DC Bus Shunt Resistor Feedback are used to detect over current trips Note that the shunts will see shoot through events which bypass the Hall current sensors The circuitry used to implement this is described below U25 A quad package comparator used for the over current threshold comparisons Each comparator has a small amount of hysteresis formed by R119 and R120 for example to ensure no output chattering occurs Note that the inverter leg shunts are compared for positive current which is when the current is flowing in a switch The bus shunt is compared for a negative value to protect against faults during braking generating R109 forms the pull up for the open collector outputs of U25 A small amount of filtering is used e g R118 C45 to prevent spikes on the shunt signals causing false trips U27 B A remaining Op Amp package used to generate the HIGH REF 4 5V from the Microchip MCP 1525 2v5 reference U26 A and B Two two input NAND gates configured as a SET dominant SR flip flop The SET dominance is important to ensure correct fault action even if the RESET input is active D5 R202 An LED and its associated current limiting resistor for the visual indication of the FAULT DS70096A page 28 O 2003 Microchip Technology Inc
85. to limit the surge of input current that would occur at initial application of power due to the discharged DC bus capacitance The initial nominal cold resistance is 5W which reduces once current flows and the device heats up Note that when the Power Factor Correction inductance L1 and L2 is in circuit that the NTC also reduces the overshoot in DC bus voltage that other wise occurs on application of power 1 4 2 2 ACTIVE POWER FACTOR CORRECTION PFC The active PFC circuit is essentially a simple boost chopper with the control aimed at shaping the input current to follow the incoming mains supply waveshape The reader is directed towards a good textbook e g Power Electronics Mohan et al ISBN 0 471 58408 8 pp488 494 for a detailed description of operation and control of the circuit The purpose of the different parts of the circuit are described below L1 A high frequency axial inductor with a single layer winding on a ferrite core This component is in series with the main inductor L2 to reduce the effect of the self capacitance of it s winding Without L1 significant high frequency 15 MHz ringing of the inductor current occurs at every transistor turn on which would increase EMI and the PFC transistor switching loss L2 A power inductor with two stacked toroidal cores made from a powdered iron material to limit the core loss while maintaining good energy storage density The particular cores used are Micrometals T
86. to the system 1 2 2 Making Power Connections It is recommended that cables be terminated with blue or red insulated crimp terminals If crimp terminals are not used care should be taken to ensure that stray strands of wire do not short to adjacent terminals or the enclosure If possible all wires should be stripped and tinned with solder before connecting to the power module terminals For the AC mains supply input standard double insulated 3 core flex cable should be used with a minimum current rating of 10A 1 mm 18 AWG A computer power cable can be used when the IEC connector is removed Note The system is designed for installation category II Therefore the incoming mains cable should be wired into a standard non locking 2 pin ground type plug The recommended output cable size is 1 0 to 1 5 mm 18 16 AWG and it should have a 600V rating This cable should also be double insulated or have a protective ground screen Access to the terminal screws is provided via holes in the lid of the enclosure A flat blade screwdriver should be used Note The user should only access the power terminals when the system is fully discharged see Safety Notice The power connections are shown in Table 1 1 and Figure 1 3 TABLE 1 1 POWER CONNECTIONS Connection Number Input Output 1 Ground Ground 2 Neutral Red Phase 3 Live Fused Yellow Phase 4 Blue Phase 5 DC Bus 6 External Br
87. tor through which the low side switch and diode returns to the DC bus The shunt is used for FAULT protection and optionally for an alternative feedback signal see Section 1 2 6 Power Module Feedback Signals and Section 1 2 7 FAULT Protection 1 4 8 8 GATE DRIVE e U22 An integrated high voltage IC IR 2112 which provides gate control of a low side and a high side power transistor As the emitter of the high side device Q3 can be at any potential between DC and DC and even beyond transiently internal circuitry must provide for the necessary level shifting to ensure correct operation The IR2112 does this without providing isolation The 2112 also monitors the low and high side power supplies and shuts down if an under voltage is detected The under voltage lockout is automatically reset by a rising edge of a firing command once a valid voltage is present See www irf com for a full data sheet m m 2003 Microchip Technology Inc DS70096A page 19 dsPICDEM MC1H 3 Phase High Voltage Power Module DS70096A page 20 The function of groups of the discrete gate drive components is explained below R51 D28 C14 C17 These components form a floating power supply for the high side gate driving stage of U22 Whenever the low side IGBT Q4 or it s anti parallel diode is conducting a charging path for C14 and C17 is formed This is because the 15V supply is referenced to the DC bus and D28 conducts When the high
88. uring switching events due to the shunt s inductance Gain inversion can lead to current control instability and false tripping of protection circuits High gain bandwidth product 10 MHz typical this is often a more important factor in determining the speed of response than slew rate in this application due to the requirements to amplify rapidly changing signals of low amplitude Note that in applications requiring less gain and or slower speed of response the MCP602 604 family offers a good alternative with even lower power supply consumption DS70096A page 22 O 2003 Microchip Technology Inc Set Up and Operation 1 46 2 INVERTER LEG SHUNT RESISTOR FEEDBACK A shunt is located between the emitter of the low side switches e g Q4 and the DC bus in every leg of the inverter A simple differential amplifier circuit is used as shown in Appendix A Sheet 3 The operation of the circuit used for the RED phase leg is described below e U24 A One quarter of the MC6024 op amp R94 R99 and C34 These provide a small amount of passive differential filtering This helps to reduce input stage overloading of the op amp that would occur due to spikes of voltage produced by the shunt s self inductance Clearly this has a beneficial effect on the output signal R84 R85 R88 and R89 The resistors form the differential configuration of the amplifier LK5 and LK6 These allow two different gain settings to be used by sh

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