Abstract: Part of hoister system in Yongcheng coal mine adopt DC motor speed control devices,which easily brings about harmonic wave and pollutes the grid.To solve this problem,a three-level active filter based LCL filter is developed to reduce harmonic wave.With a diode-clamped three-level topology,the device makes the resonant inhibition through active damping method performed by a capacitor current feedback,and applies the intelligent PSO algorithm to the LCL filter parameters design.The theory and methods used in this paper are proved to be correct and feasible by simulation,which can effectively reduce the harmonics of system.The prototype experiment showed that the developed active filter effectively compensated for harmonics produced in the DC hoist system and controlled the grid harmonic content within 5% to meet the national standard.

Key words: APF, LCL Filter, PSO Algorithm, DC Hoister