Part Number:DRV8305
Hello Everyone!
We are working on a sensor-less ESC for BLDC Motors, and using DRV8305 in 1 PWM Mode with PWM Frequency being 15.625KHz and a Motor of 150W & 1000Kv Rating for current tests. The Motor spins fine at no load condition in open loop up-to 8000RPM. But as we attach an external propeller, the motor doesn't spin above 4500 RPM. I understand that required duty cycle changes with respect to RPM i.e Commutation Frequency, as the motor needs enough power to energize before the commutation step expires. But we haven't been able to establish a proper relation between RPM and required duty cycle.
Kindly help us out in how to determine the required relationship between any BLDC motor with any Kv rating and its required Duty Cycle at a given RPM.
Or if there is any other parameter that we can read from the motor to set desired RPM without having the motor to stall.
Thanks & Regards
Aakash Vishwakarma