STEVAL-SPIN3204 - How to control a motor with very slow speed?

[AnthonyG]

Hi

I use the STEVAL-SPIN3204 board to control a motor without datasheet.

It's a 10 pole pairs motor with 36V nominal voltage, and Hall sensors. It's the only parameters I have.

I use the STSW-SPIN3204 software with IAR IDE.

My final application needs very slow speeds (10-60rpm).

I can't use the Motor Workbench because I need to use Hall sensors.

I use the current control because if I use the voltage control, the board detects instantly an overcurrent.

With the STSW-SPIN3204, my motor achieves to spin, but the motor's speed isn't my target speed (target: 200rpm, motor peed: 800rpm).

If I send a target higher than 800rpm, this speed is achieved, but for speeds lower than 800rpm, the speed is limited to 800rpm.

How can I change this "threshold"?

Is it with the LF Timer prescaler?

An other thing: How can I increase the torque? When my motor is spinning, I can stop it with one finger, and the motor don't try to send more current. (I'm not limited by the power supply)

I tried with others motors, and the result is the same. So I think it's a bad software configuration.

Thanks for your help.

[Laurent Ca...]

Dear @AnthonyG​ 

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

Laurent Ca...

[Laurent Ca...]

The question has been set only to the "Motor Control Hardware" topic (the question is not about the STM32 MC SDK). 

Best regards

[Laurent Ca...]

Dear @AnthonyG​ 

As you do not answer, I guess you don't have to solve this problem anymore, therefore I consider this thread closed.

If not, feel free to reopen it by posting a new answer.

Best regards