Abstract: Part of hoist system in coal mine adopt full digital DC motor speed control devices, which easily brings about harmonic wave and pollutes the coal mine grid. In order to solve this problem in the coal mine, the APF based on LCL-filter is developed to reduce harmonic wave in the mine grid. With a NPC three-level topology, the problem of the stability of the LCL-filter implementation is solved through the active damping method of capacitor current feedback control. Current tracking control is a key issue for APF, Considering the defects of traditional PI control, a compound control method based on repetitive theory is proposed, which is an integration of proportional control and repetitive control. The control theory is simple and easy for project implementation. Finally, the designed LCL filter and the current tracking control method are tested through simulation. And the theories are verified by experiments.