BLDCv學習教案

1、會計學1BLDCv第一頁，編輯于星期五：二十一點 十七分。第1頁/共55頁第二頁，編輯于星期五：二十一點 十七分。ElectricMotor typesACAsynchronousSynchronousInductionStepperSynchronousPMSMSwitched Rel.DC第2頁/共55頁第三頁，編輯于星期五：二十一點 十七分。BLDCBasics 第3頁/共55頁第四頁，編輯于星期五：二十一點 十七分。VWUUVW+-q3-Phase Brush-less DC MotorAccording to the theory of DC machine, the motor r

2、otational speed can be written as follows:N = ( Ud - I R ) / (Ke )While,“N” stands for the motor rotational speed“Ud” stands for the DC voltage applied to the motor windings“R” is the pure resistance of the winding while “I” stands for the winding current “Ke” is the magnet coefficient while “ ” sta

3、nds for the motor magnetic flux From the above formula, there are two methods to change the speed of DC motor: One is to change the DC voltage of the motor windings (Ud), the other one is to change the magnetic flux of the motor (). As the BLDC motor has permanent magnet rotor, only the first method

4、 can be used in practical application. The principal of generating variable DC voltage is to use PWM for chopping: change the duty cycle of the PWM voltage, proportionally change the DC voltage. NS第4頁/共55頁第五頁，編輯于星期五：二十一點 十七分。第5頁/共55頁第六頁，編輯于星期五：二十一點 十七分。第6頁/共55頁第七頁，編輯于星期五：二十一點 十七分。第7頁/共55頁第八頁，編輯于星期五：

5、二十一點 十七分。第8頁/共55頁第九頁，編輯于星期五：二十一點 十七分。第9頁/共55頁第十頁，編輯于星期五：二十一點 十七分。第10頁/共55頁第十一頁，編輯于星期五：二十一點 十七分。qTypical Switching Pattern for a BLDCHall Sequence depends on motor constructionOutput pattern levels depends on inverter topology第11頁/共55頁第十二頁，編輯于星期五：二十一點 十七分。BLDC withHall Sensors第12頁/共55頁第十三頁，編輯于星期五：二十一

6、點 十七分。qTypical Circuit Block DiagramHall Sensors detect the positionOver current protection and control via ADC第13頁/共55頁第十四頁，編輯于星期五：二十一點 十七分。第14頁/共55頁第十五頁，編輯于星期五：二十一點 十七分。Hardware NoiseSuppressionch0 gets capturedvalue for act. speedch1 comparefor phase delaych2 comparefor timeoutCC6xact. speedCC60p

7、hase delayCC61timeoutCC62COUT6y110001CCPOS2CCPOS0111000CCPOS1001111CaptureEventResets T12qBEMF-Detection/Hall Signals HW-noise filter on CCPOSx inputs (BEMF-signals)第15頁/共55頁第十六頁，編輯于星期五：二十一點 十七分。Hardware NoiseSuppressionch0 gets capturedvalue for act. speedch1 comparefor phase delaych2 comparefor ti

8、meoutCC6xact. speedCC60phase delayCC61timeoutCC62COUT6y110001CCPOS2CCPOS0111000CCPOS1001111CaptureEventResets T12q BEMF-Detection/Hall Signals HW-noise filter on CCPOSx inputs (BEMF-signals) automatic reset of T12 with interrupt actual speed by capture ch0第16頁/共55頁第十七頁，編輯于星期五：二十一點 十七分。Hardware Noise

9、Suppressionch0 gets capturedvalue for act. speedch1 comparefor phase delaych2 comparefor timeoutCC6xact. speedCC60phase delayCC61timeoutCC62COUT6y110001CCPOS2CCPOS0111000CCPOS1001111CaptureEventResets T12q BEMF-Detection/Hall Signals HW-noise filter on CCPOSx inputs (BEMF-signals) automatic reset of

10、 T12 with interrupt actual speed by capture ch0 phase delay function on ch1第17頁/共55頁第十八頁，編輯于星期五：二十一點 十七分。Hardware NoiseSuppressionch0 gets capturedvalue for act. speedch1 comparefor phase delaych2 comparefor timeoutCC6xact. speedCC60phase delayCC61timeoutCC62COUT6y110001CCPOS2CCPOS0111000CCPOS100111

11、1CaptureEventResets T12q BEMF-Detection/Hall Signals HW-noise filter on CCPOSx inputs (BEMF-signals) automatic reset of T12 with interrupt actual speed by capture ch0 phase delay function on ch1 time out function on ch2第18頁/共55頁第十九頁，編輯于星期五：二十一點 十七分。qMCMOUTSH / MCMOUTSLSW programmable state machine第1

12、9頁/共55頁第二十頁，編輯于星期五：二十一點 十七分。qMCMOUTSH / MCMOUTSLcompare CCPOSx level with programmed value 第20頁/共55頁第二十一頁，編輯于星期五：二十一點 十七分。qCCPOSx InputsqMCMOUTSH / MCMOUTSLswitch to next state on valid edge by hardware 第21頁/共55頁第二十二頁，編輯于星期五：二十一點 十七分。qCCPOSx Inputswait on edgeqMCMOUTSH / MCMOUTSLprepare next state b

13、y software 第22頁/共55頁第二十三頁，編輯于星期五：二十一點 十七分。第23頁/共55頁第二十四頁，編輯于星期五：二十一點 十七分。第24頁/共55頁第二十五頁，編輯于星期五：二十一點 十七分。第25頁/共55頁第二十六頁，編輯于星期五：二十一點 十七分。第26頁/共55頁第二十七頁，編輯于星期五：二十一點 十七分。第27頁/共55頁第二十八頁，編輯于星期五：二十一點 十七分。第28頁/共55頁第二十九頁，編輯于星期五：二十一點 十七分。第29頁/共55頁第三十頁，編輯于星期五：二十一點 十七分。第30頁/共55頁第三十一頁，編輯于星期五：二十一點 十七分。第31頁/共55頁第三

14、十二頁，編輯于星期五：二十一點 十七分。第32頁/共55頁第三十三頁，編輯于星期五：二十一點 十七分。第33頁/共55頁第三十四頁，編輯于星期五：二十一點 十七分。第34頁/共55頁第三十五頁，編輯于星期五：二十一點 十七分。第35頁/共55頁第三十六頁，編輯于星期五：二十一點 十七分。第36頁/共55頁第三十七頁，編輯于星期五：二十一點 十七分。第37頁/共55頁第三十八頁，編輯于星期五：二十一點 十七分。BLDCSensor less第38頁/共55頁第三十九頁，編輯于星期五：二十一點 十七分。nwhilei = 0 and di/dt = 0:UP = ePnby measuring U

15、Pa position detectionis possible第39頁/共55頁第四十頁，編輯于星期五：二十一點 十七分。qReal BEMF Voltage and Current: shape depends on magnets, motor speed, voltage第40頁/共55頁第四十一頁，編輯于星期五：二十一點 十七分。qZoom In: BEMF is only visible at active switching PhaseCurrentBEMFVoltage第41頁/共55頁第四十二頁，編輯于星期五：二十一點 十七分。qCurrent Commutation in

16、a CoilFreewheeling diode conductsPhaseCurrentBEMFVoltage第42頁/共55頁第四十三頁，編輯于星期五：二十一點 十七分。PhaseCurrentBEMFVoltage第43頁/共55頁第四十四頁，編輯于星期五：二十一點 十七分。qTypical Circuit Block DiagramComparators and RC-Filter detect the BEMF zero crossing for position detection第44頁/共55頁第四十五頁，編輯于星期五：二十一點 十七分。q Typical Circuit Bl

17、ock Diagram Use simple resistor divider and ADC for position detection第45頁/共55頁第四十六頁，編輯于星期五：二十一點 十七分。qSynchronize ADC on T13T13 period match can trigger the ADCequidistant sampling of analog signalsexact timing guaranteed by hardwareno timing jitter due to software delays第46頁/共55頁第四十七頁，編輯于星期五：二十一點 十

18、七分。qSynchronize T13 on T12T13 performs delay for stable measurementT13 period match triggers ADCqUseful for Current Measurement E.g. induction machine第47頁/共55頁第四十八頁，編輯于星期五：二十一點 十七分。qT13PM triggers ADCDelay between T13PM and high voltage switching event due to driving circuitqUseful for Voltage or Cu

19、rrent Measurement E.g. BEMF detectionSample shortly before power device is switched off (BEMF is noise free)第48頁/共55頁第四十九頁，編輯于星期五：二十一點 十七分。qT13PM triggers ADCDelay between T13PM and high voltage switching event due to driving circuitqUseful for Voltage or Current Measurement E.g. Current in DC link

20、path Sample shortly before power device is switched off (current is noise free)第49頁/共55頁第五十頁，編輯于星期五：二十一點 十七分。qT13 used for Modulation ADC triggerq T12 used for Phase delay q Software (for 60 sector) With every T13PMthe BEMF voltage is sampled and compared to a BEMF-wave table When crossing a limit t

21、he software generates a CHE-event (1) Speed reference is captured and phase delay for T12ch1 is calculated At T12ch1 the pattern for the next sector is switched (2)第50頁/共55頁第五十一頁，編輯于星期五：二十一點 十七分。q T13 used for Modulation ADC triggerq T12 used for Phase delay q Software (for 60 sector) With every T13

22、PM the ADC alternatively samplesBEMF voltagePhase currentThe current set value can be controlled by adjusting the PWM duty cycle第51頁/共55頁第五十二頁，編輯于星期五：二十一點 十七分。Port pin toggles when BEMF is below limitBEMFVoltagePhaseCurrent第52頁/共55頁第五十三頁，編輯于星期五：二十一點 十七分。qApplication: Line powered Industrial DrivesPower: 750 WCurrent: max. 5 AAC Input Voltage: 110 to 264 VACqFeatures:8