In order to improve capacity of resisting disturbance of the permanent magnet synchronous motor system

a speed sensorless method is proposed for speed identification. Sliding mode（ SM） variable structure control and the model reference adaptive system（ MRAS） method are combined together. Through selecting the motor body as reference model and using the output voltage and current of the inverter

the adjustable model based on flux equation are established. The speed is identified based on the two model error

using SM variable structure method. In the Matlab simulation platform

the speed sensorless method is analyzed. The results show that the proposed sensorless method has better dynamic and static performance and can accurately identify speed.