Sinusoidal commutation of a high-speed PM synchronous motor with one discrete Hall sensor

A novel rotor position detecting method of PM (permanent magnet) synchronous motor is presented in this paper using a discrete Hall sensor mounted on the stator. High- precision rotor poison signal can be obtained through proper processing although a discrete Hall sensor only give the rough position information with the resolution of ±90 electrical degrees. The conversion and compensation of the rotor position signal based on phase locked loop (PLL) are analyzed. The drive system of a 30000 rpm high-speed PM synchronous motors is designed with this method. The current harmonics in the high-speed PM synchronous motor is analyzed. The dead-time compensation technology is applied to reduce the current harmonics. Experiments are carried out to validate the proposed method. The harmonics in the stator current are restrained evidently. High efficiency and low torque ripple of the motor are obtained.