Modeling and resonant characteristics analysis of multiple paralleled grid-connected inverters with LCL filter

This paper establishes the model of multiple paralleled grid-connected inverters with LCL filter and analysis its resonant characteristics and influencing factors. The analysis results show that multiple paralleled grid-connected inverters have more than one resonant frequency, and the resonant frequency are closely related to the number, type and composition ratio of parallel inverters. Meanwhile the lower resonance frequency decreases with the increasing number of parallel inverters, and mainly affected by the control parameters and the grid strength when the amount of inverters is fixed. Simulation waveform and experiment results verify the availability of the model and the accuracy of analytical results.