Abstract: To improve the system performance of permanent magnet synchronous motor (PMSM) with LC filter, a new motor current estimation and control method based on the extended Kalman filter (EKF) is proposed in this paper. In the EKF method, the inverter side current was sampled, the actual motor current was obtained through the new EKF observer, and the estimated motor current was used for current loop feedback. The structure and parameter design of the new EKF current observer were given, and the system stability was proved by Lyapunov stability theorem. The simulation results show that, compared with the traditional Luenberger observer, the new EKF observation method has smaller current estimation error and better motor current tracking performance. The torque ripple and the harmonics can also be effectively reduced.