Overvoltage Fault During Deceleration with STM32 Motor Pilot

[Bablu]

Hello ST Team,

I'm encountering an overvoltage fault when decelerating a motor from high speeds. My system uses an STM32 F401RE microcontroller with an IHM16M1 driver board, controlled via Field-Oriented Control (FOC).

The motor operates normally at high RPMs, but when I command a speed reduction, the system immediately triggers an overvoltage fault, indicated as an "ACK Fault" in the Motor Pilot interface. 

We've already tried troubleshooting the overvoltage fault on our motor controller by:

• Increasing the voltage range in the bus voltage sensing section.

• Following the recommended steps for overvoltage fault resolution outlined in the user manual.

Despite these efforts, the issue is still happening.

What are the solutions for preventing the overvoltage fault during deceleration?

We're looking for other potential solutions or insights. Any suggestions on effective strategies would be greatly appreciated.

Thank you in advance for your support. 

Best regards, 
Rahul 

[GMA]

Hello @Bablu,

Do you intend to stop the motor when it is spinning at maximum speed?
If yes, slow down the motor by using a lower speed command before stopping it.

In your initial setup, if setting 33 V as the overvoltage threshold is not sufficient, modify it by changing the OV_VOLTAGE_THRESHOLD_V definition. The X-NUCLEO-IHM16M1 voltage range reaches 45 V. Ensure to keep some margin to avoid damaging the board.

[Bablu]

Hi @GMA,

We are experiencing an overvoltage fault not just when the motor stops, but also when we try to decrease its speed. We have already tried increasing the voltage limit, but the fault persists. Our motor is rated at 24V, and we have set the overvoltage margin to more than 30V.

Thank you 

Best Regards

[GMA]

Hello @Bablu,

When the motor decelerates, it operates as a generator and induces a voltage spike. You can reduce the spike by increasing the deceleration duration.
Through the workbench interface, raise the threshold to 33 V.

[GMA]

Hello @Bablu,

The duration is available on Speed Ramp Motor Control interface:

 

[Bablu]

Hi @GMA ,

I've followed the previous advice and adjusted the deceleration duration, but I'm still encountering an overvoltage fault. I've also checked the voltage limit settings, but I don't believe they are the root cause.

What else could be causing this issue? Any suggestions on what to check next would be greatly appreciated.

Thank you!

[GMA]

Hello @Bablu,

You can also deactivate the bus voltage sensing (a constant DC voltage will be used). By monitoring the VBUS value with a multimeter or an oscilloscope, you can check the VBUS range for your use case. During this test, consider the power board's rated range and DC supply limitations.