Multiport Traction Converter with Partial-Power-Processing DC-DC Stage for Hydrogen Rail Vehicles

Fuel cell systems in hydrogen-powered trains usually require a high-power dc-dc converter to manage the significant voltage variations from no-load to full-load conditions. This paper investigates a non-conventional propulsion system for hydrogen-powered trains integrating a multiport dc-ac stage as primary traction converter and a down-sized partial-power-processing (PPP) dc-dc converter for additional power extraction from the fuel cell. Time-domain simulations are presented to show the operation of the traction system under a standard driving cycle. Furthermore, lumped-parameter and finite-element thermal and magnetic simulations are employed to design the dc-dc conversion stage in the full-rating and PPP configurations. The results show that the PPP architecture can manage the power delivered by the fuel cell as desired, while giving attractive reductions in the size and weight of the onboard dc-dc converter.