In order to solve the chattering problem and the errors of speed and position is large in the traditional sliding mode control (SMC) for permanent magnet linear synchronous motor (PMLSM), a sensorless control method for adaptive sliding mode observer (SMO) based on phase locked loop (PLL) of PMLSM is proposed. Firstly, an adaptive law of back-electromotive force (back-EMF) is established by using Lyapunov function, and constructed an adaptive SMO. Then, calculate the position and speed by PLL instead of traditional arctangent function, which improved the accuracy of observation. Finally, build the simulation model and the results proved the superiority of the proposed method.

PMLSM， Sensorless control， SMO， Adaptive law， PLL.