Resonance Analysis and Suppression of Grid-connected Inverter Parallel System in Weak Grid

In the current era of rapid clean energy technology advances, parallel operation of multiple grid-connected inverters emerges as a leading solution in microgrid systems. This study addresses resonance risks in parallel photovoltaic inverters, especially with LCL filters in weak grid environments, proposing an innovative resolution. Beyond establishing the system's mathematical model, our approach introduces a novel grid-connected current feedback control strategy through resonance analysis. Prioritizing parameter optimization and enhancing phase and amplitude margins, this strategy offers a fundamental solution to resonance challenges in multi-inverter parallel systems. Validation on a MATLAB/Simulink platform with two parallel inverters confirms the viability of our strategy, presenting a concise yet impactful contribution to the understanding and resolution of resonance problems in microgrid systems.