A Quick Sensorless Startup Method for Ultra-High-Speed PMSM Using Predictive Current Model

Sensorless control is indispensable for ultra-high-speed permanent magnet synchronous motor due to installation issues. And the startup process must be finished as quick as possible in consideration of useful life of air bearings. A predictive current model based position observer is proposed in this paper to give accurate estimation results at low speed and realize quick startup of ultra-high-speed permanent magnet synchronous motor. The proposed method utilizes the current model in the estimated rotating reference frame to obtain the position estimation error, which is later sent to an extended state observer to acquire accurate estimation results of electrical speed and position. With the help of additional position pre-locating and inverter nonlinearity compensation, the proposed predictive current model based startup method can realize quick startup from standstill to 30000 rpm within 1 second. Furthermore, the proposed position observer is quite efficient and takes less than half execution time of traditional observers in embedded developing. An experimental platform is built to validate the properties of the method. And experimental results show that performance of the proposed observer is desirable at low speed and can realize quick and reliable startup of ultra-high-speed permanent magnet synchronous motor.