Sensorless BLDC Motor Control Using dsPIC30F2010

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AN992FIGURE 2:PICDEM MCLV BOARD FUNCTIONALITYdsPIC30F2010PWM3HPWM3LPWM2HPWM2LPWM1HPWM1LFLTAAN0AN1AN2AN3AN4AN5FaultVDCDemand3-PhaseInverterIBUSR49 R41 R34 R36Phase Terminal Voltage FeedbackR44R52VDCBLDCVBUSR63R64Except for the dsPIC30F2010 device, the basic blockdiagram is exactly the same as that used in AN901.• A pot selects the demand for the speed.• VBUS voltage is sensed as VDC using resistorpairs R63/R64. VDC/2 is used as the “zerocrossing”voltage for back EMF sensing.• Feedback voltage is sensed using resistor pairsR34/R36, R41/R44 and R49/R52.• Current feedback is provided through a simpleoperational amplifier circuit (U10A)• Fault input is received through a comparatorcircuit (U7D) connected with the current feedbackcircuit. The current is sensed using a 0.1 ohmresistor (R26). The current gain is 11 and thethreshold of the comparator can be adjusted usingpot R60.You can very easily adjust the values of the resistors toaccommodate the current capabilities of the motorbeing used for the application. The motor drive circuit,on the other hand, is designed to drive a 24V BLDCmotor. You can change the drive requirement of themotor (refer to the PICDEM MCLV DevelopmentBoard User’s Guide for details on how to change thehardware for use with motors greater or less than 24V).On the low side, the voltage limit is 10V. On the highside, the voltage limit is 40V. It is important to note thatthe heat sink on the IGBTs have very limited heat dissipation,so high power requirements may not be easilymet with the PICDEM MCLV board.To use the PICDEM MCLV board for this application,use the jumper settings shown in Table 1 and the motorconnections shown in Table 2.TABLE 1: JUMPER SETTINGS FORPICDEM MCLV BOARDJumperSensorless ControlJ7, J11, J13 Short between 2-3J15OpenJ8,J12,J14OpenJ10, J16, J17, J19 OpenTABLE 2:Connector J9LabelM1M2M3GMOTOR CONNECTIONSSensorless ControlPhase C (Red)Phase A (White)Phase B (Black)Ground (Green) If availableThe colors referenced in Table 2 are as per the Hurst24V motor available from Microchip. The ground wire issometimes not available on some motors.Once the code is developed and downloaded to thesystem, you will need to press switch S2 to start andstop the motor. The pot marked REF (R14) sets thedemand for the speed. It is rotated clockwise toincrease the speed of the motor.Due to the limited I/O on the dsPIC30F2010, the LEDson the board are not used to signal fault conditions.Instead, fault conditions are displayed on Windows®HyperTerminal® on your PC using the serial port.DS00992A-page 2© 2005 Microchip Technology Inc.
AN992PROGRAMMING THE dsPIC30F2010The dsPIC30F2010 can be programmed using thePICDEM MCLV board. Due to the limited I/O resourceson the dsPIC30F2010, the serial port is shared with theprogramming pins. When you are ready to program thepart, DIP switch S4 should have its TAB in the PRGMdirection. When programming is completed, the DIPswitches must be moved to the DEBUG position to executethe code. If the IDC2 is connected to the PICDEMMCLV board as a debugger, then the connector at J6should be attached. If, however the ICD2 is being usedas a programmer, then the connector at J6 should beunplugged from the ICD2 for normal execution.The following configuration settings are required for theapplications to work on a PICDEM MCLV board:Oscillator Source:Primary OscillatorPrimary Oscillator Mode: XT w/PLL 8xComm Channel Select: EMUC2 and EMUD2Other settings can be enabled or disabled as needed,or modified in the application.SOFTWARE MODIFICATIONS:The software has not been modified significantly fromthat described in AN901. However, the user interface tothe LCD and the debug routines have been removed.The LCD interface has been replaced by the SerialUser Interface mentioned in the next section. The UserInterface does add to the code space and will require adsPIC30F3010 device during the development stage ofthe application.During the development mode you must set:#define DEVELOPMODE TRUEThis setting in the def.s file allows for all the conditionalstatements in the code to automatically enablethe UART and run the user interface mode. Once thecode has been fully developed, you can then select:#define DEVELOPMODE FALSEThis setting in the defs.s file disables the serial userinterface and hard codes the parameters to Flashmemory.To ensure that the code fits into the dsPIC30F2010,you must use the space optimization option in the C30compiler options. From the MPLAB Main menu, selectProject>Build Options>Project. When the BuildOptions dialog displays, select the MPLAB® C30 taband set Categories>Optimization>Optimization level>s(for space optimized).Note:The source code for this application isavailable on the Microchip web site(www.Microchip.com), appended to theelectronic (pdf) version of this applicationnote.USER INTERFACEThe user interface is necessary to tune the differentparameters used in the sensorless BLDC motor controlapplications. There are 45 user parameters that can bemodified in the applications. For more details on theseparameters, their functions/uses and how to tune them,refer to the Using the dsPIC30F for Sensorless BLDCControl (AN901) application note.In AN901, the user parameters are modified using anLCD display and key switches. Since an LCD displayis not available on the PICDEM MCLV board, the userinterface has been modified to a 2 wire serial interface.The new user interface for this application uses theRS-232 port on the dsPIC30F2010 connected to acommunication terminal (e.g., WindowsHyperTerminal) running at 19200 Baud.The communication terminal is then used to changeparameters in the user interface. All the parameters inAN901 that were set on the PICDEM MC1 Motor ControlDevelopment Board using the LCD screen can nowbe set through the serial interface.Table 3 lists the parameter names, abbreviations anddescriptions. A total of 45 control parameters are availablefor the user interface.The parameters are categorized by:• Motor Parameters - parameters that relate to themotor• Starting Parameters - parameters that relate tothe starting ramp• Control Parameters - parameters that relate tothe different PI or PID control parameters used inthe software• Limit Parameters - parameters that relate to thevarious limit settings in the software• Board Parameters - parameters that relate to thecomponents on the board and how they interactwith the software© 2005 Microchip Technology Inc. DS00992A-page 3
Page 1: AN992Sensorless BLDC Motor Control
Page 5 and 6: AN992TABLE 3:MOTOR CONTROL PARAMETE
Page 7 and 8: AN992Motor ParametersMotor Paramete
Page 9 and 10: AN992Starting ParametersThe Startin
Page 11 and 12: AN992Run Time ModeAs noted before,
Page 13 and 14: AN992APPENDIX A:SCHEMATICSFIGURE A-
Page 15 and 16: Note the following details of the c

Sensorless BLDC Motor Control Using dsPIC30F2010

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