Research on Multi-envelope Mode and Its Hybrid Mode of Resonant Soft-switching Inverter

To achieve the desired high power density and high efficiency of photovoltaic micro-inverters, a new control strategy called multi-envelope control based on resonant soft-switching inverter has been proposed, which could effectively solve the problem of zero-crossing distortion. In order to further reduce the switching loss caused by high switching frequency, the multi-envelope and its hybrid mode have been further studied and compared with the traditional control strategy in terms of zero crossing distortion, output current harmonics, and switching loss. In order to validate the theoretical analysis, a 500W single-phase full-bridge inverter was constructed using PSIM. Additionally, simulation verification was conducted to assess its performance in both grid-connected and off-grid states. The simulation results indicate that the multi-envelope mode and its hybrid mode can effectively alleviate the zero-crossing problem and reduce the output current harmonics when compared to the traditional critical current control mode. Additionally, the high loss problem of the multi-envelope mode can be resolved through reasonable mixing.