Study on Four-Quadrant Operation of Brushless DC Motor Control Method

Brushless DC motors, which are applied to the human skeleton boosters, require frequent switch of four-quadrant operation states of forward rotation, backward rotation, electro motion and braking control. This switch generally requires to be soft and smooth without overshoot, big impulse or speed mutation. The general performance of the brushless DC motor control system cant meet this requirement. The main purpose of this paper is to solve this problem by adopting bipolar PWM control which makes it possible to realize the motor operating in four-quadrant and improve its characteristics. In addition, the paper proved the correct and efficiency of this method by using simulation .