Patent ID: 6771033
Filing Date: 2004-08-03
Classification: H02P,Y10S

Abstract:
A drive control system for sensor-less motor for driving a motor and executing PLL control to rotary drive by switching a current of a field coil in each phase of the multi-phase motor depending on the rotating phase of the motor, comprising:power feeding means for feeding electrical power, for the predetermined period, to a field coil in the phase other than the detection phase by defining a desired phase as the detection phase at the time of driving a motor: induced voltage detecting means for detecting a voltage induced on said coil of the detection phase through said power feeding; magnetic pole position detecting means for detecting the magnetic pole position of a rotor from the amplitude condition of said induced voltage; driving means for determining the power feeding phase for drive of motor based on the detection result of said magnetic pole position detecting means, and executing the power feeding for drive depending on said determination; and controlling means for alternately conducting detection of magnetic pole position by said power feeding means, induced voltage detecting means, and magnetic pole position detecting means, and power feeding to drive a motor by said driving means; wherein unlock of the PLL control is detected when the motor rotation is accelerated with the PLL control, and the control sequence for recovery to normal condition is executed by setting a flag when unlock is detected.