Abstract

Photovoltaic (PV) to electrolyzer power systems are an attractive research topic since the PV produced power can be optimized by skipping power conversion into AC and producing a direct DC-DC interface. Existing DC-DC power conversion systems to directly interface the PV generation and Hydrogen (H2) electrolyzer are mainly based in interleaved structures or multi-resonant converters. Soft-switching characteristics are also suitable for these conversion topologies and DCX converters are then serious candidates to be used. DCX provides an isolated high efficiency solution but the DCX-based two-stage converter topology must be optimized in order to obtain better efficiency and energy yield. In this work a detailed comparison of DCX topologies is given for a PV to H2 application. The proposed optimized system is validated through simulation in a multi-string electrolysis system, showing the relevance of the solution for this application. The proposed approach reaches a global maximum efficiency of 98.2%. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.