STM32 FOC Motor Control SDK: Motor RPM limit in torque control mode possible?

[MFrej]

In our application, we need a PMSM motor to run mostly in torque control mode.

However, we also want to have a RPM limit in certain operating conditions.

With the FOC library v5.4.0 (running on a Nucleo-F302RB), I coudn't get this behavior to work.

In torque control mode, the speed limits MOTOR_MAX_SPEED_RPM and MAX_APPLICATION_SPEED_RPM are both ignored, and the motor spins up to the maximum speed possible by the DC bus voltage.

Does the library support a speed limit in torque control mode?

[cedric H]

Hello,

By default there are no such kind of limit when you are in torque mode.

If you wan to limit the speed, and still control the motor in torque mode, the suggestion I can propose is that in your application code, you read the speed periodically and if the speed start to reach the limit you apply a ramp to decrease the torque.

This behavior is really application specific and it is the reason why it is not implemented by default.

the API you need are :

MC_GetMecSpeedReferenceMotor1

MC_ProgramTorqueRampMotor1

if you want to reduce the torque without applying a ramp, you can still force IQD_ref with :

MC_SetCurrentReferenceMotor1

those API are implemented in mc_api.c

Hope it helps

Regards

Cedric

[Laurent Ca...]

The question has been moved from the "Motor Control Hardware" section to the "STM32 Motor Control" section (the question is about the STM32 MC SDK). 

Best regards