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:
- 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