AUTHOR=Meng Xiangjian , Fang Jingyang 

TITLE=A half-bridge distributed static compensator with a DC-link filter capacitor of a reduced size LCL filter

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.929676

DOI=10.3389/fenrg.2022.929676

ISSN=2296-598X

ABSTRACT=Distributed Static Compensators (DSTATCOM), composed of power converters and passive filters, have been extensively utilized in the distribution system to improve its power quality (PQ). For selection of passive filters, the LCL filters with smaller sizes and lower costs are increasingly adopted to replace the conventional L filters. However, the filter components of LCL filters are normally designed for the application of grid-connected inverters (GCI), and therefore these passive components can be further optimized when applied to the DSTATCOM, where the grid-injected current is mainly capacitive. In this paper, a novel LCL-filtered half-bridge DSTATCOM topology is proposed, where the conventional filter capacitor of LCL filter is replaced by the DC-link capacitors with relatively larger capacitances. In consequence, the grid side inductance can be dramatically reduced from the order of millihenry to several microhenry. Furthermore, the current stresses of semiconductor switches can be decreased. In addition, the power flow analysis and filter design procedure are presented in this paper. It is revealed that a constant DC-link voltage can be always maintained and the voltage variation across each capacitor can be well regulated with properly designed filters and controllers. Experiments were carried out on a down-scaled laboratory prototype, and simulation and experimental results are presented to verify the effectiveness of the proposed DSTATCOM topology.