Speed-stabilization control of a high-speed PM synchronous motor without high-precision sensors

Speed-stabilization control of a 30000 rpm highspeed PMSM (permanent magnet synchronous motor) is achieved without speed sensors. The rotor position of the PMSM is detected by a discrete Hall sensor with the resolution of ±90 electrical degrees. Circuits based on phase locked loop (PLL) are designed to obtain the speed signal and high-precision rotor position signal. Two filters with different constant time are designed to improve the dynamic performance of the speed-stabilization system because the low-pass filter is adapted in the speed loop. Experimental and simulated results show the validity of the proposed method.