I'm using DRV8301-69M-KITwith our high speed motor.
When I tried to increase motor speed from 40000rpm to 50000rpm, acceleration stopped at 47000rpm. It was impossible to reach to 50000rpm.
(I already confirmed that motor can rotate over 60000rpm with another driver unit. And no false found in excel chart. )
When I observed that PWM signal from C2000 to DRV8312, I found that PWM duty ratio is not changed at 47000rpm.
Its duty ratio is about 90%. (On time 90%, Off time 10%)
Until 47000rpm, duty ratio is changing to increase drive current. But at 47000rpm, it stopped.
At that time, off course driver current not increased. As the result, motor speed stays at 47000rpm.
Test condition: Vbus=15V, PWM frequency 90kHz
Question.
Why does PWM duty ratio not change? Is there any limitation? Or is there any parameter to set it?
Regards.