Hi,
I am implementing motor controller DRV8301 (level4 FOC) which can take 60A.
The PMSM motor specs
a) its designed to take 20 Amps.
b) It has a stator resistance of <0.1 ohms and hence needs just under 2V for pumping 20 Amps current at no load (V=IR).
c) Power source 48V batteries.
Parameters defined DRV_GAIN == 40 and thus BASE_CURRENT is 20.625 Amps.
While start up or stall condition of the motor (i.e., Back emf is 0 & under load) the current drawn would be maximum. However under current PID the current doesn't flow to the motor. The ammeter reading indicates less than 0.5 amps. Tweaked the gains but no improvement.
Changed the DRV_GAIN == 10 and thus BASE_CURRENT is 82.5. Now the motor is able to start under load (~6 Kgf) drawing 3 Amps.
Checked the Back EMF. The attached screen shot indicates that back EMF generated at 60 RPM is less than ~40% of the base voltage. Hence ample scope to increase the start up current.
Is there any way I could increase the start-up current a bit more. Pl suggest.
Thx