A Design Method of LCL-filter for Three-phase Shunt Active Power Filter

LCL Compared with the traditional L filter, the filter has higher high-frequency impedance so that the switching ripple current can be better filtered. This paper presents a LCL filter design method for three-phase shunt active power filter (SAPF). The scheme is designed with the consideration of the inherent resonance problem, the effective attenuation of ripple current, the tracking performance of compensating current and the loss of original damping. The lower limit of inductance on inverter side is designed according to ripple requirement, and the upper limit of total inductance is designed according to tracking speed, so as to determine the range of inductance. Then L-2 is determined by inductance ratio. The parameters of LCL filter are optimized by analyzing the wave diagram of LCL filter and other function curves. Finally, the validity and superiority of the proposed method are proved by simulation and experiment compared with the L filter.