Speed control of permanent magnet motors using sliding modeobservers for induced EMF position and speed estimation

摘要

This paper presents a speed control system for a permanent magnetsynchronous motor (PMSM) in which the sliding mode technique is used toestimate the induced EMF, rotor position and speed. The electricaldynamic equations of PMSM are modified to obtain the sliding modeobserver model and then the variables are estimated by using onlymeasured stator currents and voltages. Firstly, the observer of theinduced EMF is implemented using analog devices. Taking the outputsignals of this observer, the estimated speed and position variables arenumerically calculated. Information on the induced EMF is used for theimplementation of feedforward action in the current loop. Speed andposition information are used for speed loop control and variabletransformations, respectively. Simulation results of these observers arepresented. Experimental results confirm the good performance of theclosed loop speed control using the proposed observer