An on-line position error compensation method for sensorless IPM motor drives using high frequency injection

Abstract

This paper addresses the position error issue existing in sensorless IPM motor drives using the high frequency injection (HFI) method. A simple-to-design on-line compensation method is proposed based upon filter group delay theory, which substantially minimizes the error between the estimated position and the actual position caused by filters in a conventional HFI system. The method determines the position error compensation based upon a demodulation delay and a velocity or rotational frequency of the electrical machine. Experimental results with a 10-hp interior permanent magnet motor are presented showing improved sensorless performance using the proposed method.