A sensorless PMSM drive using a two stage extended Kalman estimator

This paper presents an efficient implementation of the extended Kalman estimator used for the estimation of position and rotor velocity of a permanent magnet synchronous motor. 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 estimator in a standard implementation, our modified optimal two-stage Kalman estimator reduces the number of arithmetic operations, allowing higher sampling rate, the estimation of parameters or the use of a cheaper microcontroller.