A Four-Phase Interleaved Buck-Boost Converter With Changed Load Connection for the Fuel Cell Activation

When the fuel cell (FC) is being activated before used in industrial applications, a power conditioner is needed to interface the FC with the load. Due to low current ripples, high output power, and simple structure, the multi-phase interleaved non-isolated DC-DC converter is most suitable for the power conditioner. This paper proposed, analyzed and designed a four-phase interleaved buck-boost converter with changed load connection (CLC-FIBC) for the FC activation with characteristics as simple structure, wide input current, high current, and low current ripples. The operating principle and mathematical model of the CLC-FIBC were firstly analyzed, derived and presented, and then mathematical equations of transistor voltage stress and inductor current ripple are derived respectively. Besides, this CLC-FIBC was compared with several DC-DC converters to prove the superiority. The simulation and experimental prototype was built to validate the theoretical analysis after presenting some design considerations. Simulation and experimental results show that the CLC-FIBC has characteristics of both step up/down function, high power, wide input current range, and low current ripples.