Electrical – Advantages of using a current loop in driving a BLDC motor

brushless-dc-motorpid controller

I've been reading the answers to the question:

How to realize constant acceleration control for BLDC motor?

However, it is not specified what are the advantages of adding a current control loop to drive the motor. Why not just drive the motor PWM from the output of the velocity loop PI controller?

Best Answer

Yes, you can just drive BLDC motor only with velocity loop. But please note that without current loop you can overload current of stator coils when torque and power at the shaft will be higher than rated. Secondly, if you control current - it's possible to control torque directly. When the load on the shaft is being increased - it's faster to detect increasing current than decrease of velocity of motor so response time of regulation control is faster.