Leakage Current Suppression Method Based on Optimal Switching Sequence Model Predictive Control for Flying Capacitor Three-Level Inverter

The leakage current of non-isolated grid-connected converter is a key issue. Firstly, based on predictive control, the discrete model of three-phase flying capacitor three-level grid-connected inverter is established. Secondly, the equivalent common-mode voltage model is established, and the common-mode voltage characteristics of each switching vector are analyzed to suppress leakage current. After that, the relationship between the switching sequence and the voltage balance of the flying capacitor is analyzed. The flying capacitor voltage is balanced by changing the switching sequence, and the leakage current can be suppressed. Finally, the effectiveness of the method is verified by simulation results.