High performance direct vector control of an asynchronous motor based on EKF

It is important for high performance AC drive systems to be robust against motor parameters´ variation and load disturbances. Taking account of the model uncertainty and nonlinearity, a rotor flux observer based on extend Kalman filter (EKF) technology is proposed in a direct vector control system of asynchronous motor. In this observer, the rotor resistance is taken as an extended state. Then the precision of rotor flux orientation is improved by reducing the resistance variation affects on flux estimator. A new load torque feedforward strategy for the speed controller is also presented, which makes the system capable of rejecting load disturbances. Simulation results proved the efficiency of this whole system.