Charge Control for Critical Conduction Mode Soft-Switching Grid-Tied Inverters

Critical conduction mode (CRM) based soft switching inverters are beneficial for achieving efficient grid connection of photovoltaics. In order to improve system performance, a charge control scheme is proposed in this paper. By taking the output charge quantity of the bridge arm as the control target, the system model based on the output charge quantity of the bridge arm is established. The specific implementation processes of the proposed charge control scheme are provided, and the analysis is conducted in the discrete-domain. Finally, a 1-kW single-phase LCL-type gridtied inverter is built for experiment verification. Experimental results demonstrate that compared to the average current control scheme, the proposed scheme significantly improves dynamic response capabilities during current fluctuations.