Motor not spinning
Hey guys,:eyes:
I'm trying to drive a 3kw brushless motor using HALL sensors with a single shunt custom board, based on the stm32f103rb(LQFP64) with the following configuration:
MCSDK_v5.4.7-FULL
MCU: STM32F101RB, 72MHz, Ext Clock
Motor parameters:
- 24 pole pair
- Nominal DC voltage of 72v
- 3KW:flexed_biceps:
- 120deg sensor displacement with 315deg placement electrical angle
Current sensing parameters:
- 1.67 milliohm single shunt with a maximum current of 100A (it's not a good way to sense current for a low inductance motor, but currently it's my only choice.):pile_of_poo:
- Overall gain of 8.85
- Trise around 2us
Driver parameters:
- PWM frequency 16KHz
- dead time 1.5us
- cut-off frequency of 3000rad/s
high side of the W phase (same for others):
Unfortunately, the motor is not spinning. I tried to fix speed regulator parameters, increase dead time and play with the current sensing rise time, but that didn't make any differences and the motor drew many current (almost short circuit), sometimes there is some kind of speed feedback errors.
I tried to log the startup procedure like this:
:: Speed control callback :: current state 0: IDLE
:: Speed control callback :: current speed: 0
:: Speed control callback :: Iq: 0, Id: 0
:: Speed control callback :: Bus Voltage: 59
:: Speed control callback :: Motor Power: 0
:: Speed control callback :: current state 0: IDLE
:: Speed control callback :: current speed: 0
:: Speed control callback :: Iq: 0, Id: 0
:: Speed control callback :: Bus Voltage: 59
:: Speed control callback :: Motor Power: 0
:: Speed control callback :: current state 6: RUN
:: Speed control callback :: current speed: 0
:: Speed control callback :: Iq: 1870, Id: 5136
:: Speed control callback :: Bus Voltage: 59
:: Speed control callback :: Motor Power: 0
:: Speed control callback :: current state 6: RUN
:: Speed control callback :: current speed: 12
:: Speed control callback :: Iq: -1187, Id: -468
:: Speed control callback :: Bus Voltage: 59
:: Speed control callback :: Motor Power: 9
:: Speed control callback :: current state 10: FAULT NOW: Under Voltage
:: Speed control callback :: current speed: 0
:: Speed control callback :: Iq: 0, Id: 0
:: Speed control callback :: Bus Voltage: 29
:: Speed control callback :: Motor Power: 0
:: Speed control callback :: current state 10: FAULT NOW: Under Voltage
:: Speed control callback :: current speed: 0
:: Speed control callback :: Iq: 0, Id: 0
:: Speed control callback :: Bus Voltage: 28
:: Speed control callback :: Motor Power: 0
:: Speed control callback :: current state 6: RUN
:: Speed control callback :: current speed: 0
:: Speed control callback :: Iq: 226, Id: -834
:: Speed control callback :: Bus Voltage: 43
:: Speed control callback :: Motor Power: 0
:: Speed control callback :: current state 6: RUN
:: Speed control callback :: current speed: 393204 //error
:: Speed control callback :: Iq: -1445, Id: -1806
:: Speed control callback :: Bus Voltage: 59
:: Speed control callback :: Motor Power: 15
:: Speed control callback :: current state 10: FAULT NOW: Under Voltage
:: Speed control callback :: current speed: 0
:: Speed control callback :: Iq: 0, Id: 0
:: Speed control callback :: Bus Voltage: 28
:: Speed control callback :: Motor Power: 0
I've had success driving this motor with the same build without a transistor-based FET driver (using an IR2101 driver) and a 5mOhm shunt resistor (otherwise pretty much the same).
The attached image below shows the output waveform of all three phases, it seems that the waveforms of phases 2 and 3 have unwanted pulses at the beginning and end of the TIM1 period.
Please help me to solve the problem, as you know there are so many parameters to interact with, so I hope to find exactly what's the problem.
Thank you </3🙋