Energy Management DC System Based on Current-Controlled Buck-Boost Modules

This paper presents the design guidelines of a series hybrid fuel cell system, including control and protection loops. This hybrid system consists of a fuel cell (FC), an auxiliary storage device (ASD), and current-controlled DC-DC converters responsible for managing the energy transfer between the FC, the ASD, and the load. The main advantages of the selected converter are its voltage step-up and step-down properties, high efficiency, and low input and output current ripples, which enable it to be positioned in all system locations, provided the corresponding controllers are suitably designed. Also, using the same module for all system converters simplifies the design and construction tasks. The theoretical analyses have been verified by simulations and validated experimentally on a 48 V 1500 W purpose-built DC bus.