In the wind power generation system

wind power generators need to accurately control the torque according to the torque command from the master control system. In the traditional control system

the current command is directly calculated according to the torque command and then it is controlled by the current closed-loop. However

because of the influence of the parameters

the torque control accuracy is lowered as a result. For this reason

this paper proposes a stator flux and electromagnetic torque observer for the permanent magnet synchronous motor (PMSM) based on a full order sliding mode observer. Compared with the traditional voltage model based flux observer

the proposed observer has overcome the problems of integral initial value and integral drift. Compared with the traditional current model based flux observer

the proposed observer is independent of the parameters of the inductance and permanent magnet flux linkage. Based on the observed stator flux

the electromagnetic torque can be accurately observed. In addition

the torque control accuracy can be greatly improved by the torque closed-loop. Simulation and experimental results have verified the effectiveness of the proposed algorithm.