Modeling and controller design for a four-switch buck-boost converter in distributed maximum power point tracking PV system applications

Due to its simplicity and identical input/output voltage polarity, the four-switch buck-boost converter (FSBBC) has found a lot of attentions in series-connected distributed maximum power point tracking (DMPPT) PV system applications. In this paper, the small-signal ac model is derived to analyze the dynamic behavior and stability of an autonomous PV module (APVM) which is composed of a PV module and a FSBBC. Moreover, the design of the controller with appropriate control requirements will be proposed and the switching strategy with smooth transition during mode change will be explained. Finally, computer simulation and hardware experiment results are presented and discussed to verify the performance of the APVM.