A Load-Adaptive Modulation for Soft-Switching Grid Connected Inverters

To reduce the number of actions of the auxiliary branch of the soft switching inverter and decrease the complexity of the modulation process, a load adaptive PWM (LA-PWM) strategy is proposed. Its outstanding feature is to align all auxiliary circuit supported communication (ACSC) processes to the switch timing edge at any power factor, thereby achieving zero-voltage-switching (ZVS) turn-on of all main switches through one auxiliary circuit action, significantly reducing switch losses and auxiliary circuit losses. This article provides equivalent circuits and mathematical models for each operating state of the circuit under the proposed LA-PWM strategy, analyzes the conditions for implementing soft switching, and outlines the characteristics of the inverter. Finally, simulation and experimental results validated the effectiveness of the proposed method.