High Ratio Non‐Isolated DC–DC Converter for Hydrogen Battery Using a 50 kW PEM Fuel Cell

This paper proposes a DC DC converter dedicated to high efficiency and high voltage conversion ratio, which is well suited for fuel cell applications. At high voltage conversion ratio the proposed converter, named here mirror boost converter, has a better ratio of active/freewheeling times which, compared with conventional structures, reduces the penalty on efficiency induced by the high conversion ratio. This converter also uses eight interleaved coupled-inductors, which reduces the current and voltage ripple and makes possible to use of smaller passive components. Coupling all phases with an inter-cell transfotiner (ICT) also improves the power density, volume and losses of the magnetic component compared to separate inductors. A comparison with a classical double boost converter is realized using the same material. The proposed converter reaches a peak efficiency of 96.5% at 17 kW and 95.3% at 42 kW for a voltage conversion ratio around 10. The mirror boost converter has about half the losses of the double boost converter at same fuel cell power and delivers 69% more power at the maximum measured current phase.