PLL control system based on FPGA for brushless DC motor

Brushless DC motors (BLDCM) are widely used for industry control field. Steady speed control accuracy and speed control bandwidth are the key indexes in industrial application. In this paper, a phase-locked loop control system for BLDCM is proposed to achieve better dynamic performance and steady-state accuracy. A ten-state phase-frequency detector is designed to detect the speed error of the rotor. And an all digital PLL control system for BLDCM is realized with Verilog HDL. Finally, a control and drive circuit based on FPGA is implemented and applied to momentum flywheel to verify the feasibility of the proposed control system. Experimental results show that steady speed accuracy could be achieved better than 0.1%.