I've learned that an electric speed controller switches battery voltage on and off on each phase to drive a BLDC motor and uses PWM to control speed. Then I have some confusion.
The coils inside a BLDC motor themselves are large inductors, inductors always try to hold current. For one phase, when you switch on, the current can be gradually increased and eventually able to create enough torque, when you switch off, the coil will try to hold current and create arcing at where you cut the circuit, causing heating inside ESC.
Taking PWM into account, electric arc will be created every cycle. If the PWM frequency is too high, then there is not enough time to get enough current to create torque.
Is there some mechanism to allow motor coils to keep current, and how?