MRAS based estimation of speed in sensorless PMSM drive

Abstract

To increase the mechanical robustness of drive system and to make the drive cheaper elimination of the position sensor is highly encouraged. Sensors are not reliable in explosive environment like in chemical industries and may cause the EMI problem. This has made the speed and position sensorless drive very attractive. A speed and position estimator for PMSM drive has been investigated. In the algorithm the PMSM used as reference model. The adaptation mechanism uses a PI controller to process the error between reference model and adjustable model. The estimation algorithm used is independent of stator resistance, computationally less complex, free from integrator problem because back-emf estimation is not required and provides stable operation of drive system. So the performance at low and zero speed is also good. The estimation algorithm is implemented in MATLAB. Simulations results show the validity of MRAS estimator presented here.