Resonance Characteristics Analysis of Grid-Connected System with Photovoltaic and Energy Storage Based on Modal Analysis

The grid-connected system with photovoltaic (PV) and energy storage (ES) experience harmonic resonance problems due to interaction coupling between multiple types of converters and different switching operating states of different converters, which can affect the power quality of the system. Therefore, it is important to reveal the relevant resonance mechanism of the grid-connected system with PV and ES. This paper addresses the resonance analysis problem in the grid-connected system with PV and ES under different operating states. Firstly, the Norton equivalent model of the PV and ES system are derived based on system topology and control methods. Secondly, the resonance characteristics of the grid-connected system with PV and ES under three different operating states are investigated based on resonance modal analysis (RMA) and participation factor (PF) calculations. Thirdly, considering the differences in harmonic interaction among the three operating states of grid-connected system, the resonance mode, resonance frequency, and node sensitivity of the system in different states are revealed. Finally, based on MATLAB/Simulink platform, the correctness of model and analysis results is validated by a simulation model of the grid-connected system with PV and ES.