A GaN-Based DC-DC Modular Switched Inductor Converter for Shading/Mismatch Mitigation in Bifacial Photovoltaic Systems

Bifacial panel strings generate energy from both the incident and albedo radiation. The variability in albedo radiation on each module, based on its position, emerges as a primary source of mismatch, alongside factors such as partial shading, orientation, and dust accumulation. To optimize power extraction despite these mismatches, DC-DC converters have proven more effective than bypass diodes. This paper introduces a buck-boost DC-DC converter topology, implemented with GaN transistors and operating at a switching frequency of 1 MHz, that execute differential power processing (DPP). GaN switches allow to achieve converters with high compactness and efficiency thanks to their characteristics such as the channel high electron mobility, the wide bandgap and the bidirectionality. The converter has been designed and simulated to maximize power extraction in a bifacial solar panel comprising three series-connected bifacial modules, mitigating the different effects of albedo radiation and mismatches on each module.