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STM32F301: Speed feedback error at high temperature

Question asked by L. G. on Sep 4, 2017
Latest reply on Sep 8, 2017 by L. G.

Dear Sirs,
I have same problems to drive one SM-PMSM at ambient temperature of 65°C.

At 25°C there is not any problem, all works as expected, but at 65°C a speed feedback error appear.

I checked the current sensing circuit, but all the electrical  signals on the OPAMP, power supply are ok.
The ambient temperature close to the micro-controller (rated T85) is around 70°C.
No any improvement if I change the motor BEMF parameter to compensate the BEMF changes due to the increased temperature.

Here below my settings:
- STM32F301C8T6;
- ST FOC library 4.2;
- sensor-less (Observer+PLL);
- one shunt and external OPAMP for the current sensing;
- Torque control;
- ambient temperature 65°C.


Do you have some hints to find the cause of the problem?

Thank you in advance for the help