High frequency (high pitch beep) sound when start motor

[Alex Chen]

Hi,

I'm using STM32F303RB with ihm08m1 to drive a 36V BLDC motor. When I start motor, a high frequency sound (like a high pitch beep) is being made in the motor. The sound is a problem and very annoying, is there any way or solution to avoid this sound?

The PWM frequency was set to 10Khz. I have changed it to 12Khz but the high frequency sound is still audible.

Thanks.

[Peter BENSCH]

An audible noise can always be heard when the PWM frequency is below an age-dependent value. Children and teenagers can easily detect frequencies of around 16...18kHz, while this limit decreases with increasing age. The volume of this noise also depends on the mechanical design of the motor coils.

If you want to shift the frequency into the (for humans) inaudible range, you should choose a frequency of at least 17...18kHz.

When your question is answered, please close this topic by choosing Select as Best. This will help other users find that answer faster.

Good luck!

/Peter

[Alex Chen]

Hi Peter,

​

Thanks for the reply.

I have tried with frequency above 12Khz (13Khz ~ 16Khz ), but I got MC_FOC_DURATION error and the motor stops due to this error.

So if the frequency seems to be limited to 12Khz and below, is there any other method or solution to solve the noise problem?

​

Thank you.