Efficient and Reliable Power-Conditioning Stage for Fuel Cell-Based High-Power Applications

Abstract

Mainstream power-conditioning devices such as boost converters are frequently utilized for developing a compatible interface between a fuel cell, electrical storage, and high power loads. The conventional power stage comprising a unique boost converter suffers from low efficiency and poor reliability due to excessive power losses, particularly in high-power applications. Additionally, the presence of high ripple contents can reduce the lifespan of the fuel cell itself. With this background, this paper proposes and experimentally validates a physical components-assisted equivalent power-sharing strategy between parallel-coupled boost converters (PCCs) that is subjected to a wide spectrum of low-voltage–high-power conditions. The operation of PCCs is bottlenecked by several practical limitations, such as the presence of inner circulating currents (ICCs) and stability issues associated with the equivalent sharing of power. To overcome these limitations, a module of reverse blocking diodes is suggested to avoid ICCs between the PCCs. Further, an equalization filter is properly placed to improve the equivalent power-sharing capability. The proposed strategy is theoretically assessed in a MATLAB/Simulink environment with a 6 kW proton exchange membrane fuel cell (PEMFC) as the main power source. A scaled-down laboratory setup consisting of an 810 W PEMFC stack, an electronic load, three boost converters, and a filter circuit is then designed and critically evaluated. A consistent agreement is observed between the experimental findings and the simulation results under realistic operating conditions.