Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title A Study for Mutual Interference of LCL Filter Under Parallel Operation of Grid-Connected Inverters
Authors Lee Gang ; Joungjin Seo ; Hanju Cha
DOI 10.6113/TKPE.2021.26.2.75
Page pp.75-81
ISSN 1229-2214
Keywords LCL filter; Transfer function; Hardware in the loop simulation; Off-line simulation; Grid connected converter
Abstract This study analyzes the resonance characteristics caused by the mutual interference between LCL filters and the grid impedance under the parallel operation of the grid-connected inverter using the LCL filter. These characteristics are verified through simulation and experiment. Two inverters are used to connect to the grid in parallel, and the system parameters, including the LCL filter, are set to the same conditions. In the case of inverters running in parallel at the point of common coupling, the presence of grid impedance causes mutual interference between the LCL filters of each inverter, and the deviation of the filter resonance frequency is analyzed to understand the parallel inverter. The correlation between the number of devices and the size of grid impedance is simulated by PSIM and verified by MATLAB. By connecting the real-time digital simulator Typhoon HILS to the DSP 28377 control board, the mutual interference characteristics are tested under the condition of two inverters running in parallel. The experimental and analysis results are the same, indicating the validity of the analysis.