Speed and Parameter Estimation of Vector Controlled Permanent Magnet Synchronous Motor Drive

Abstract

This paper proposes, a new method for speed and parameter estimation of Permanent Magnet Synchronous Motor (PMSM) drive. From the view point of cost, consistency, compatibility and environmental issues the PMSM is operated without speed sensor. Therefore, we require some speed estimation approach to operate the motor in closed loop. In this paper, an Active-Power (p) based Model-Reference-Adaptive-System (MRAS) is used to estimate the speed. The p-MRAS based speed estimator depends on machine parameters (i.e., stator resistance and mutual flux linkage). Thus, any variation in these will affect the speed-estimation-technique performance. In general, variation of stator resistance is quite common when compared to mutual flux linkage. Hence, stator resistance estimation is required. A novel method for stator-resistance (Rs) estimation technique (i.e., modified active power MRAS (p = : MRAS)) is proposed which is independent of speed. Proposed p-MRAS based speed estimator performs satisfactorily at low/no- load conditions when compared to the reactive power (Q-MRAS) based speed estimator. Extensive simulation is performed in MATLAB/SIMULINK to observe the performance of the proposed controller.