METHOD OF INFERRING INITIAL POLE POSITION OF PERMANENT MAGNET BRUSHLESS MOTOR

摘要

A method of inferring the initial pole position of a permanent magnet brushless motor (8), wherein a gamma -axis and a delta -axis which form an electrical angle of 90 DEG are arbitrarily defined in a space coordinate system, a unit (2) for controlling the current in the gamma -axis direction is constituted of a closed loop and a unit (3) for controlling the current in the delta -axis direction is constituted of an open loop, and an interference current i delta which is generated in the delta -axis direction when a current command iyRef in the gamma -axis direction is given as a stepped alternating current command. If the sign of the product of the integral value of the interference current and the gamma -axis current command value is positive, the gamma -axis is advanced by a minute angle DELTA theta , while if the sign is negative, the phase is lagged by a minute angle DELTA theta to make the gamma -axis agree with a real magnetic axis (d-axis) or a -d-axis which leads the real magnetic axis by 180 DEG .