Investigation of output side filter effect on the compensation performance for active power filter

The widespread use of lots of nonlinear loads based on kinds of power electronics devices have brought us great harmonics and reactive current pollution on isolated power system or public utility grid and reduced the quality of power supply. Installing active power filter in power side is commonly used to remove harmonics and reactive current of supply, making it provide fundamental component. APF will bring the power supply great amount high-frequency harmonics as the same as the main power switch when it is working, therefore it is necessary for APF to add high-pass filter on output side to reduce the quantity of high-frequency. The paper introduced compensation principle and mathematical model first and researched the influence of output filter to APF qualitatively. In addition, it proposed a design method of parameters about output filter combined with its topology and features based on three-phase three-wire shunt active power filter. The proposal is proved to be effective and feasible by MATLAB simulation and actual project verification of R&D 70KVA APF.