Abstract: Based on the vector space decoupling mathematical model of dual three-phase permanent magnet synchronous motor, the model reference adaptive system (MRAS) was applied to the sensorless control of dual three-phase permanent magnet synchronous motor. Using Popov's hyperstability theory, this paper analyzed and proved that there were some problems in the application of traditional MRAS for interior permanent magnet synchronous motor, and the problem was that the linear compensator with unit matrix I could only realize speed identification within a certain speed range. In order to make MRAS work effectively in a wide speed range, a new linear compensator was designed and a new speed adaptive law was derived. The proposed method was verified by simulation and experiment. The results show that the method can realize the accurate identification of rotor position and speed, and has good performance.