Steady Speed Flywheel Drive System based on Phase-Locked Loop

In this paper, a set of flywheel drive system based on phase-locked loop (PLL) is designed and implemented. The drive motor of the steady speed flywheel is a brushless DC motor (BLDCM). Two drive modes of the motor, sine wave drive and square wave drive are implemented to compare steady speed performance. The resolver is used to obtain higher-precision position. PLL control strategy is used to replace the closed-loop PI control method, which eliminates strong saturation characteristic and large overshoot in the system. In the design of PLL, ten-state PFD is used to eliminate glitch and speed up the response of the system. The loop filter (LF) of the PLL is designed to improve system performance. The digital PLL controller is implemented by FPGA. In addition, the phase noise of the PLL system is analyzed and suppressed. The PLL control system is modeled and implemented. The simulation and experiments show that sine wave drive has higher steady speed accuracy than square wave drive. Experiments verify that in the PLL control flywheel drive system, the error of steady speed is less than 0.03%.