INSTANTANEOUS TORQUE CONTROL METHOD OF BRUSHLESS DC MOTOR

摘要

PURPOSE: Instantaneous torque control method of brushless DC motor minimizes a ripple torque with a maximum efficiency according to d-g-0 reference axis theory. CONSTITUTION: Instantaneous torque control method of BLDC motor measures a back EMF wave of each phase of BLDC motor, converts the back EMF wave to d-q-0 axis value by a conversion matrix, detects a motor position value and a motor rotation speed, and generates a torque command about a desired motor speed. The control method uses a back EMF waveform converted by the d-q-0 axis, a rotation speed, and the number of polarity pairs of motor, the torque command value, so that a current value for a maximum efficiency and a minimum ripple torque is calculated on the d-q-0 axis. Then, a current value of the d-q-0 axis is converted to a current value of a-b-c axis. and each phase current of motor stator follows the current value of a-b-c axis. Thereby, the instantaneous torque control method of brushless DC motor minimizes a ripple torque with a maximum efficiency according to d-g-0 reference axis theory.