Open loop motor control with both voltage and current regulation

摘要

An open-loop pulse width modulation (PWM) motor control for an induction motor includes a voltage regulator loop which is wrapped around a current regulator. When a load is suddenly encountered by the motor, voltage drops at the output of the current regulator. This is sensed and fed back to a voltage regulator and to a current limiter which then adjust the input signal to the current regulator to prevent an overcurrent that will trip a circuit protection device. The voltage regulator and current limiter may be implemented in either analog or digital circuitry.