Patent ID: 9584050
Date: 2017-02-28
CPC Classifications: H02P

Claim:
1. A motor drive device including a power switch unit for supplying power to multi-phase coils of a motor, and a control unit for on-off controlling the power switch unit, the control unit including: a speed signal generator that generates a rotation speed signal indicating rotation speed; a PWM signal generator that acts on the power switch unit to control the power switch unit so as to generate a coil-applied voltage; and a phase advance information generator that has a preset phase advance amount of the coil-applied voltage corresponding to given speed according to load characteristics of the motor, wherein the phase advance information generator sets the phase advance amount by using a polygonal line that approximates a load characteristic curve of the motor, wherein the motor drive device applies a voltage to the multi-phase coils according to a phase advance signal from the phase advance information generator.