In order to improve capacity of resisting disturbance and reduce cost of operation control strategy of voltage sensorless is proposed. Three-phase stator voltages are estimated by conducting state of inverter and DC voltage

speed observer is designed by model reference adaptive system（ MRAS）. Based on mathematical model of asynchronous motor

two kinds of rotor flux observation models are obtained. According to the suitable adaptive institutions to get accurate actual rotating speed

adjust model parameters in real time. This control method is simple and has high control precision. Finally

experiments prove the feasibility of the control strategy.