Brushless DC motor controller detects rotor position with motor voltage such that influence of DC source voltage fluctuation to motor voltage remains offset

摘要

The brushless DC motor controller has a rotor position detector (13) that detects the rotor position with the motor voltage such that the influence of DC source voltage fluctuation to motor voltage remains offset. The brushless DC motor controller has rotor position detector that detects rotor position while performing PWM control of the invertor circuit (11). Phase and frequency of motor voltage are determined with the estimated rotor position. The revolution number detector (14) detects the motor revolution number. The control unit adjusts duty ratio so that influence of DC source voltage fluctuation to mean value of motor voltage is reduced.