Robust Control of a Speed Sensorless Permanent Magnet Synchronous Motor Drive

This paper presents the application of the Linear Quadretic Gaussian (LQG) controller to the state estimation and feedback of a speed sensorless permanent magnet synchronous motor (PMSM) drive system. The nonlinear model of the motor has been linearized on the basis of field orientation principle. The standard Kalman filter technique has been used to estimate the speed, position, and load torque by measuring only the stator current. The optimal state feedback gains and the Kalman state space model have been calculated off-line in order to reduce the computational burden. The proposed controller has the advantages of robustness, easy implementation and adequate performance in the face of uncertainties. Moreover, the load disturbance can be rejected without affecting the overall performance. Computer simulations have been carried out in order to validate the effectiveness of the proposed scheme. The results show that accurate tracking performance of the PMSM has been achieved.