A Power Electronics Conversion Topology for Regenerative Fuel Cell Systems

The aim of this paper is to present and analyze a novel power electronics conditioning topology for hybrid energy generation and storage systems for residential applications. The hybrid energy system combines regenerative fuel cells, photovoltaic generators and batteries. The proposed power conditioning topology, which can be implemented at low cost, can provide bi-directional power flow with high frequency ohmic isolation, thus providing regenerative and charging capabilities. The proposed topology presents a number of advantages: 1) provides bi-directional power flow to the system, permitting the use of regenerative fuel cells and/or batteries, 2) incorporates a high frequency power transformer, thus exhibiting high power density, 3) employs a low voltage battery configuration, eliminating the necessity of a battery management system, 4) draws low ripple current from the fuel cell stack at a low switching frequency, 5) provides fuel cell start-up and battery charging through the utility grid and/or any possible renewable energy converters and 6) exhibits unity input power factor when operating in grid connected mode. Analytical as well as simulation and experimental results are presented for the proposed topology.