A Multiple Energy Conversion Channels Fusion Grid-Connected Inverter for Large-Scale PV Active Power Injection Preventing Power Loss Caused by Insufficient MPP PV Voltage

In the context of the increasing global demand for renewable energy and the rapid development of large-scale photovoltaic (PV) power generation, efficient grid connection of PV energy has become crucial. However, existing grid-connected inverters (GCI) face issues such as high-power losses issue of inductive GCI (IGCI) or limited operating ranges issue of capacitive GCI (CGCI). This article introduces a multiple energy conversion channels fusion GCI (MC-FGCI) for large-scale PV power injection. First, MC-FGCI is proposed based on a new topology circuit configuration. Second, an equivalent circuit model of IGCI and CGCI is introduced to calculate the critical point for channel switching. The IGCI and CGCI efficient operating boundaries are determined based on the critical point. Third, based on the efficient operating boundaries, a finite state machine based method is proposed to choose the optimal VSI for high-efficiency grid connection. Finally, experimental results show that compared to previous multiple parallel IGCI (MP-IGCI), the proposed MC-FGCI saves around 11% power loss by eliminating the lossy dc/dc link. Compared to MP-CGCI, the proposed MC-FGCI expands the active power injection range under low maximum power point (MPP) voltage.