Performance enhancement of a sensorless PMSM drive with load torque estimation

This paper presents a comparative study of two sensorless Permanent Magnet Synchronous Motor drive control algorithms using an optimal two stage extended Kalman filter. Beside the estimation of position and rotor velocity with and without the estimation of load torque is considered. An algorithm proposed by C.S. Hsieh and F.C. Chen in 1999 for linear parameter estimation is extended to the non-linear estimation, where parameters such as position and velocity are present in the transition matrix and in the augmented state space. Compared to a straightforward implementation of the extended Kalman filter, our modified optimal two-stage Kalman filter reduces the number of arithmetic operations, allowing higher sampling rate, the estimation of parameters or the use of a cheaper processor. Experimental results validate the theoretical analysis and show the feasibility of the proposed estimation technique.