High-performance Flywheel Speed Control System Based on Phase-Locked Loop

This paper designs and implements a set of high-performance flywheel speed control system based on phase-locked loop. The flywheel which is usually driven by the permanent magnet synchronous motor (PMSM) is an important actuator in spacecraft attitude control system. In the traditional PMSM speed control, the double closed-loop PI control method is often used, which has strong saturation characteristics and large overshoot in the system. PLL is adopted to overcome the shortcoming. The digital PLL has higher accuracy than the analog PLL and shorter running time than the software PLL. It can be implemented by FPGA which has a higher integration level. In addition, the improved ten-state phase-frequency detector is presented to solve the output voltage glitches of the three-state phase-frequency detector of the general PLL and accelerate the responding speed of the system. The source and influence of the phase noise of PLL are analyzed. The phase noise is effectively suppressed by increasing the frequency of phase detecting. Experiments show that the error of steady speed is less than 0.02%.