Performance of Submodule Level Differential Power Processing Architecture in Mismatched PV Systems

In this paper, the voltage equilibrium (VE) method combined with the differential power processing (DPP) architecture is utilized to address the issue of the power loss in the photovoltaic system under mismatch conditions. Specifically, the submodule integrated converters (subMIC) based on the bidirectional flyback converter are used to balance the output power of each submodule by extracting or injecting current to the output nodes of each submodule. The experimental results show that the VE method can significantly improve the total output power of the system and solve the multi-peak problem of the characteristic curve under different mismatch conditions. In addition, the experimental results show that in extreme cases, executing the protection algorithm, the system's maximum output power is not obviously reduced compared to the traditional architecture, which illustrates the necessity for the protection algorithm.