Sensorless control of PMSMs based on parameter-optimized MRAS speed observer

A scheme of a model reference adaptive system (MRAS) based on the theory of parameter optimization for the PMSM servo system is described in this paper. The scheme can promptly work out the speed of the rotor without any other position/speed sensor. Different from the other MRAS-based speed observers which constructed according the theory of stability customarily, by using the error between the measured phase currents of actual motors and theoretic phase currents acquired by the mathematical model of motors as the parameter to be optimized, the proposed method can gain the speed of rotor with fast response and better performance. The stability of MRAS is analysed subsequently. In the scheme, only a few parameters are needed and satisfactory performance can be achieved. So this scheme is very simple to be used as the position/speed observer of the PMSM servo system. Finally the simulation and experimental results confirm the validity and advantage of the proposed method.