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DRV10970: Delay from PWM change to output voltage change.

Part Number: DRV10970

I have a PID controller getting velocity from hall sensor changes and outputting PWM to DRV10970. PWM frequency is 94 KHz.

With a step change in PWM to a lower duty cycle, the motor continues to accelerate for several commutation cycles before it starts to decelerate, suggesting the DRV output did not change immediately.

Is there a predictable lag from PWM change to output change?

  • With a step change in PWM to a lower duty cycle, the motor continues to accelerate for several commutation cycles before it starts to decelerate, suggesting the DRV output did not change immediately.

    Hi,

    Can you post the waveform to show this delay behavior? 

    Do you have large inertial load? One good way to prove this: capture the waveform of pwm input and the UVW output during pwm duty decreasing. The duty cycle of the UVW should be reduced according to the pwm input.

    Is there a predictable lag from PWM change to output change?

    I depends on the inertial load.

    Brian

  • My observation was incorrect. With a more careful experiment, there is no delay apparent.

    Sorry for the distraction!