Study on LLCCL Filter-based Control Strategy for PCS Converters
Distributed new energy generations-integrated systems commonly use passive low-pass filters to effectively at-tenuate the high-frequency harmonics generated by converters.The filtering characteristics of the filter directly determine the performance and volume of the system,and the development of high power density converters requires further im-provement of high-frequency harmonic attenuation effect of filters.In view of the aforementioned problem,this work pro-posed the uses of an LCLLC filter and the corresponding control strategy.The former was to achieve simultaneously notch effect at the switching frequency and high attenuation characteristics of LCL filter for high harmonics.The latter was to u-tilize filter capacitance series damping resistance for suppressing the resonance frequency of LLCCL filter,and PR control-ler and phase compensation algorithm for attenuating low frequency harmonics.The proposed filter and control strategy were verified,both simulatively and experimentally,effective in suppressing system resonance and reducing harmonic con-tent of grid-connected current and voltage.