Abstract:

Although the conventional sensorless algorithm based on Kalman filtering (KF) can eliminate the impactof model error and measurement error on the estimated state variables to a certain extent,heavy computation loadand high cost may simultaneously occur.In order to solve this problem and keep the advantages of the original algo-rithm,a novel sensorless control strategy based on the optimal two- stage Kalman filtering is proposed in stationarytwo-phase coordinates for permanent magnet synchronous motor.In this new strategy,stator currents in the stationa-ry reference frame are taken as the full- order states and the back- electromotive- force is taken as the augmented sys-tem state.In order to improve the parameter identification precision,software phase- locked loop is adopted in thecontrol strategy to estimate the rotor speed.Experimental results show that the proposed strategy is mathematicallyequivalent to the traditional Kalman filtering,with an operation time reduction of 24.49%.

Key words: permanent magnet synchronous motor, sensorless control, optimal two- stage Kalman filtering, phase-locked loop