PV Panel-Integrated High Step-up High Efficiency Isolated GaN DC-DC Boost Converter

Inhalt:
PV systems consisting of series connected PV panels suffer from reduced power output if the panels within a string receive unequal irradiance. One possible solution to this problem is to provide each panel with a high step-up DC-DC converter that allows to connect all converter outputs in parallel at the input of a central DC-AC converter feeding the PV power into the mains. In this paper, a classification of high step-up DC-DC converter concepts is presented. The isolated series resonant converter in half-cycle discontinuous conduction mode with an additional boost stage is selected as best suited concept and optimized by means of an efficiency/power density (η-ρ) Pareto optimization. This also includes an adpation of the modulation scheme for low output power in order to maximize the conversion efficiency. Based on the optimization results a converter prototype is presented and efficiency measurement results are shown.