Buck boost four-phase converter for fuel cell activation considering loadconnection change

When the fuel cell (FC) is being activated before used in industrial applications, a power conditioner isneeded to interface the FC with the load. Due to low current ripples, high output power, and simplestructure, the multi-phase interleaved non-isolated DC-DC converter is most suitable for the powerconditioner. This paper proposed, analyzed and designed a four-phase interleaved buck-boostconverter with changed load connection (CLC-FIBC) for the FC activation with characteristics assimple structure, wide input current, high current, and low current ripples. The operating principle andmathematical model of the CLC-FIBC were firstly analyzed, derived and presented, and thenmathematical 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. Thesimulation and experimental prototype were built to validate the theoretical analysis after presentingsome design considerations. Simulation and experimental results show that the CLC-FIBC hascharacteristics of both step up/down function, high power, wide input current range, and low currentripples