Rotor Position Estimation for PMSM Based on Sliding Mode Observer

Most methods to estimate the rotor position of permanent magnetic synchronous motor (PMSM) suffer from the motor parameters, which are difficult to be applied due to the complicated algorithm. This paper presents a sliding mode observer (SMO) to estimate the rotor position of PMSM. The SMO makes use of the error between the estimated current and measured current. And the phase lag, which is caused by the low pass filter, is compensated in a proper way. The convergence of the SMO is guaranteed. A novel estimated speed is used to improve the systematic stability. High performance sensorless drive of the PMSM based on SMO is established and the whole system is simulated by matlab. Simulations show the effect of variation of the torque and speed on the estimated rotor angle. From these experiments, it is found that this method is more robust and easier to be applied.