Abstract

In this paper, an analysis and design of a wide input range dc-dc converter is proposed along with a robust power control scheme. The proposed converter and its control are designed to be compatible with a fuel cell power source, which exhibits 2 : 1 voltage variation as well as a slow transient response. The proposed approach consists of two stages: a three-level boost converter stage cascaded with a current-fed two-inductor boost converter topology, which has a higher voltage gain and provides galvanic isolation from the input source. The function of the front-end boost converter stage is to maintain a constant voltage at the input of the cascaded dc-dc converter to ensure optimal performance characteristics and high efficiency. At the output of the first boost converter, a battery or ultracapacitor energy storage is connected to handle slow transient response of the fuel cell (200 W/min). The robust features of the proposed control system ensure a constant output dc voltage for a variety of load fluctuations, thus limiting the power being delivered by the fuel cell during a load transient. Moreover, the proposed configuration simplifies power management and can interact with the fuel cell controller. Simulation and the experimental results confirm the feasibility of the proposed system.