Controlling an electric motor

摘要

In one method for controlling an electric motor, current turn-on and turn-off rotor-position angles for each motor phase are chosen to substantially maximize the absolute value of average motor torque when the motor is operating in two different quadrants of motor torque and motor speed. The first quadrant has positive motor torque and positive motor speed. The second quadrant has negative torque and positive speed. The third quadrant has negative torque and negative speed. The fourth quadrant has positive torque and negative speed. In another method, the motor is operated in at least one of the first and third quadrants and in at least one of the second and fourth quadrants, wherein the absolute value of motor speed is limited when the motor is operating in the first or third quadrants but not in the second or fourth quadrants. In one example, the motor operates a vehicle brake caliper.