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How to tune sensorless start-up of low inertia motor

Senior II

I am using an STM32G431 running the ST motor control library for FOC sensorless control. My motor is running but the start-up performance is not satisfactory. I have about a 10% start failure. I have watched the YouTube video: Motor Control Part5 - 7 FOC with STM32 (STO, PLL, Cordic, MTPA, FW, FF) and they show a plot of Observer Elec Angle and Observer BEMF as shown here: Note the bemf amplitude is very clean and uniform, no modulation.

0693W00000GWgThQAL.jpgFor my motor I think the low inertia could be a problem. The start current is about 500mA but the run current is only about 35mA. My similar profile of Observer Elec Angle and BEMF is shown here:

0693W00000GWgUGQA1.jpgNote the ramp-up BEMF is modulated quite a bit. I think this leads to the high failure rate. I get MC_START_UP failures. I've tried tuning everything I can think of but can't find a good solution yet.

Can anyone give me some guidance on this?



Laurent Ca...
Lead II

Dear @BTrem.1​ 

Sorry for the late answer.

Do you have still this problem to solve?

And just in case, if not, do not hesitate to share the final solution you found. Thanks by advance.

Best regards