High-Bandwidth Grid-Connected Inverter to Enhance System Robustness Against Weak Grid

The multiple-input multiple-output (MIMO) matrix of the multi-inverter paralleled system based on different parameters is established, and three criteria to ensure the stability of the total grid current and interactive current are put forward. Furthermore, the robustness of the system with different switching frequencies for modules is analyzed, and the introduction of a high-bandwidth inverter into the system is found to be effective in suppressing low-frequency resonance. Then, the interaction stability between the high-frequency and low-frequency module is analyzed, and the switching frequency of the high-bandwidth inverter is selected. Finally, a prototype of the high-bandwidth inverter based on GaN is built in the lab. The effectiveness of the high-bandwidth grid-connected inverter to improve the robustness of the system in weak grid is verified by the experiment.