DRV8307 CW/CCW error when slow down

Hi Will,

We will look into this and get back to you.
While wait, would you run a few more tests to confirm the reaction is different between CW and CCW?

Hi Rick,

the video have show the problem in both direction.

Thanks for the reply.

Hi Will,

Thank you for the clarification. We believe the DRV8307 is not able to follow the quick changes in PWM.

The DRV8307 was not intended for an application with quick speed changes. Using 1 hall operation after the motor has locked, the commutation is predicting between and may not be able to follow the large swings of PWM.

We believe the DRV8308 would be a better fit. When using the DRV8308, it is recommended to set the DRV8308 in 3 hall mode. This will use all 3 hall sensors to commutate.

wenfuu, can you see if there's any dependency on how slowly you turn the pot? It is well known that sudden changes in the duty cycle can cause motors to lock up (with BLDCs and especially steppers), so ramp functions should always be used. If the problem you're seeing still happens while ramping, that sounds like a different problem.

Best regards,
RE

thanks! With ramp, it worked just fine.