Flux observer for field oriented induction motors based on EKF

The rotor field oriented control has brought essential advances in AC variable speed drive system. The induction motor drive promotes the simplicity and robustness further, and the most important problem must be solved in field oriented control system: the rotor flux observation. Based on the former researches, this paper proposes the rotor flux observation method using the theory of Extended Kalman Filter. Because of the multiplication terms of state variables, the induction motor model is the non-linear state equations. To estimate the state variables of motor model and gain the rotor flux signals, extended kalman filter algorithm is used to observe them. The satisfied simulation results prove that extended kalman filter algorithm can real time observe rotor flux very accurately. The simulation results show the EKF-based field oriented control system has good static and dynamic performance.