Abstract

A modular fuel cell system has many advantages: (a.) it is fault tolerant under fuel cell and/or converter fault conditions, (b.) it is capable of supplying partial load power if one or more of the one stack section is damaged, and (c.) it distributes heat more evenly throughout the cell while maximizing the power delivered from each stack section. By introducing modular dc-dc converter interfacing with high-power energy storage devices, a fuel cell system can be tailored to provide time sustainable responses to sudden high power load demands. A design example is presented, where a dc-dc converter interfaces a 1-kW, three-section fuel cell stack with a supercapacitor/lithium-ion hybrid energy storage bank. Three different current-boosting arrangements are considered: (i.) a supercapacitor bank, (ii.) a lithium-ion bank, and (iii.) a hybrid bank. The current-boosting time sustainability of these modular fuel cell systems with hybrid energy storage is analyzed.