Mass-optimal design methodology for dc-dc converters in low-power portable fuel cell applications

Fuel cell systems have not significantly penetrated the low-power (< 50 W) portable energy source market, largely due to complexity of control and the balance-of-plant systems required. Even though the fuel cell and fuel container may scale down well, the pumps, blowers, and power converters required may dominate the system mass. This paper focuses on the tradeoff between efficiency and converter mass, and achieving the design objective of minimum mass of both converter and fuel. The effect of desired run-time, or mission duration, on the optimal dc-dc converter design was explored in detail. The effort focused on boost converters; however, the methodology can be applied to any converter topology. In an example case, at a mission length of 100 h, the optimized convert er saved 91 g of system mass when compared to an off-the-shelf dc-dc converter.