Hello,

I am in trouble to drive a BLDC Motor -170W with a 3-phase driver circuit, which is designed by me.

My PWM frequency is 40 kHz and I just try to get a graph about the relationship between the stall current (I mean the current with blocked motor shaft) over PWM duty cycle (from %10 to %70)

In trapezoidal driving mode; why the stall current is rising linear up to %50 PWM duty cycle and rising exponentially over %50 PWM duty cycle? What difference happening over %50 PWM duty cycle?

PWM/Current

100 / 0.5A

200 / 1A

300 / 1.5A

400 / 2A

500 / 2.5A

600 / 4A

700 / 15A

What could be the possible reason for it?

Is this normal?

Thanks and looking forward to your reply.

I am in trouble to drive a BLDC Motor -170W with a 3-phase driver circuit, which is designed by me.

My PWM frequency is 40 kHz and I just try to get a graph about the relationship between the stall current (I mean the current with blocked motor shaft) over PWM duty cycle (from %10 to %70)

In trapezoidal driving mode; why the stall current is rising linear up to %50 PWM duty cycle and rising exponentially over %50 PWM duty cycle? What difference happening over %50 PWM duty cycle?

PWM/Current

100 / 0.5A

200 / 1A

300 / 1.5A

400 / 2A

500 / 2.5A

600 / 4A

700 / 15A

What could be the possible reason for it?

Is this normal?

Thanks and looking forward to your reply.

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