METHOD AND APPARATUS FOR ENCODERLESS OPERATION OF A PERMANENT MAGNET SYNCHRONOUS MOTOR IN AN ELEVATOR

摘要

A permanent magnet synchronous motor is controlled using d-axis current and q-axis current along with respective d-current and q-current feedback loops. The speed and position of the motor are determined by injecting a first signal into the d-axis current and observing the response in the q-current feedback loop. Part of the q-current feedback signal is demodulated with a second signal which is 90 degrees out of phase from the first signal. The demodulated signal is preferably sent through a low pass filter before being received by an observer controller. The observer controller outputs a position estimate which is used to modify the d-current feedback signal and a speed estimate which is used to modify the q-axis current.