Abstract: The compound position sensorless control technology of hub motor is studied, and the switching method of the speed transition interval is improved to increase the reliability of drive system in electric drive armored vehicle. A permanent magnet synchronous motor （PMSM）control system based on double closed loops of torque and current was built, for which the maximum torque per ampere （MTPA）control below the base speed and the flux-weakening control above the base speed are used. A simplified high frequency pulse injection method is used at low speed, and a model reference adaptive system （MRAS） is used at medium and high speeds to realize the rotor position identification in the full speed range. The variable weight weighted control switching method is adopted, and the working interval selection of the two algorithms is improved in the process of algorithm switching. The system hardware and software resources are greatly saved while assuring the identification accuracy. The simulated and experimental results show that the proposed sensorless algorithm can identify the speed and rotor position accurately in the full speed range, and the new switching method enables the motor to achieve smooth transition in the speed switch interval and ensures the reliable operation of motor. Key

Key words: hubmotor, positionsensorless, simplifiedhighfrequencypulseinjection, modelreferenceadaption, fullspeedswitchingcontrol