PUBLICATIONS

This study proposes a second harmonic reduction method for zero-voltage switching (ZVS) operation of the DC/DC converter in a

fuel-cell system. In this system, a boost-type DC/DC converter and a single-phase inverter are interconnected. Second harmonic

oscillations are generated in the DC link that interconnects the DC/DC converter and the inverter. The ripple component reduces the

input current generated during ZVS operation. Owing to this effect, the total efficiency of the system is decreased. Additionally,

stress-induced effects are experienced by the fuel-cell owing to this ripple component, ultimately decreasing the lifetime of the fuel

cell. To ameliorate the effects of second harmonic ripples, a type-II current controller is used in the DC/DC converter to generate an

adequate controller gain at the target frequency. The validity of the proposed control method is verified by PSIM simulations and

experiments with the use of a fuel-cell system rated at 1 kW.