Resonance coupling analysis of multiple differently parameterized grid-connected inverters in new energy generation

Abstract

This study investigates the coupling problem between different types of resonances in the system of multiple differently parameterized inverters. The coupling between the inverters and the grid, as well as between differently parameterized inverters, can lead to different types of resonances, which have different resonance characteristics. Due to the absence of resonance coupling relationship analysis, it is difficult to form a unified and complete understanding of the system resonances that are formed by the superposition of different types of resonances. In this paper, the system model is established, and the expressionsof the interactive current circulating between the parallel inverters and input-grid current injecting the power grid can be obtained. Stability analysis of the interactive current and input-grid current reveal characteristics of different types of resonances, and thus the resonance coupling relationship is obtained. It helps to form a complete understanding of system resonance characteristics, and then obtain all system resonance cases. The effects of system parameters on the resonance characteristics and harmonic interaction are analyzed. Finally, the correctness of the theoretical analysis is validated through simulations and experiments.