A Modular Fuel Cell, Modular DC-DC Converter Concept for High Performance and Enhanced Reliability

Abstract

Bad or mal performing cells in a fuel cell stack cause uneven heat distribution and reduced terminal voltage. As a consequence the overall output power of the system is reduced. Moreover continuous operation under these conditions may not be possible due to excessive heat generation in underperforming cells. In this paper a modular fuel cell powered by a modular DC-DC converter is proposed. This approach electrically divides the fuel cell stack into various sections, each powered by a DC-DC converter, allowing loading each section in the stack according to its state. That is better performing sections handle more load than underperforming sections while the output voltage of the system is kept regulated. In addition the proposed approach can bypass mal-functioning sections while the rest of the stack can continue operation, thus improving the reliability of the system. Experimental results on a 150W prototype confirm the benefits of the proposed approach.