Motor making audible noise

[ThisIsDursun]

Hello everyone 

We successfully designed a custom board using the STMCSDK V6.4.1 and here is its specifications:

MCU: STM32F030K6T6

POWER BOARD: Based on STEVAL-IPM10B

we successfully got a motor running and its nominal values are as follows:

Pole Pairs: 5

Vbus = 400V, Current = 2Amps, Speed = 1500rpm.

We used the same board with another motor:

Pole Pairs: 40

Vbus = 400V, Current = 2Amps, Speed = 500 rpm

The First one runs smoothly and everything is fine, but the second one is making some annoying audible noise inside the motor. We tested it with a commercial board and its totally fine, so the motor isn't the problem.

I have taken these steps so far and none of them have worked:

1: decreasing and increasing the pwm frequency 

2: decreasing the pi coefficients for the PLL

3: decreasing the G2 coefficient for the observer 

4: decreasing both kp and ki for torque and flux control loops

5: decreasing and increasing deadtime for switching 

6: decreasing and increasing the sampling cycles for current channels 

I don't know which workaround to try anymore.

Can you please give me some advice on how to eliminate this noise, hardware and software speaking?

It would be great thank you all

[STuser2]

I am not sure what audible noise you mean, since i have similar problem huge sound but this is during the time of acceleration of the vehicle once the speed is achieved, maybe it comes to stable state the noise is gone and runs smoothly. I tried similar methods of reducing the gains, but it has not improved, i am using Hall sensor FOC.

[ThisIsDursun]

Hey @STuser2  thanks for your reply!

It's like whistling or something

In my case, there is no difference between the stable phase and the acceleration phase, this noise exists all the time

Decreasing the cutoff parameter reduces it but it's still significant!

[ThisIsDursun]

@GMA 

Sir could please give us some advice?

The same issue happens with STEVAL-IPM10B too, so the custom board itself isn't the problem either.

What changes might help solve the issue?

Huge thanks!

[GMA]

Hello @ThisIsDursun,

Did you use the Motor Control Profiler tool for both motors (the Motor Control Profiler tool is not available on the STM32F0 series)? 
Do you have another STM32 series control board, such as one based on the STM32G4, to run some tests? The STM32F0 series is limited for investigation.

[ThisIsDursun]

Yes I have used the motor control profiler tool for both motors and have done it with NUCLEO-F303RET6 along with an original STEVAL-IPM10B.

The speed control worked perfectly, but the same thing happened during the profiling process, and the noise was obvious.

I have also a NUCLEO-G431RB board too.

I'm looking forward to knowing what tests you want me to run

Thanks a lot 

[GMA · Accepted solution]

Hello @ThisIsDursun,

With F3 or G4 board, and using motor pilot high-speed high-speed plotting, you can plot the following parameters: STOPLL_ROT_SPEED, I_Q_MEAS/I_Q_REF I_D_MEAS/I_D_REF which are the current commands, I_A/I_B which are the measured currents.
As mentioned, changing the Current regulator Cut-off frequency has a noise impact, using the Motor Pilot advanced settings, you can dynamically tune the Torque/Flux PID to find the optimal PID values.