Chattering reduction based on equivalent control gain depended method for PMSM speed estimation

In this paper a new method of chattering reduction is proposed using the Equivalent Control Methodology to preserve the benefits of applying Sliding Mode Observers (SMO) in PMSM sensorless control. The encountered chattering phenomenon is suppressed using a promising gain adaptation technique, while the observer effectiveness is investigated in estimation of Modified Back EMF, rotor speed and angle of PMSM. Essentially this approach is a sliding mode observer-based method embedding a simple gain adaptation algorithm to obtain as possible an optimum chattering reduction. In this implementation the PMSM model and proposed Sliding Mode Observer (SMO) observer are both expressed in the γδ estimated reference frame. Also the reduction of chattering phenomenon is demonstrated through simulations for sensorless speed control of PMSM in an extended speed rage considering model uncertainties and disturbances.