Dynamic modeling and control design for bi-directional DC-DC converter for fuel cell vehicles with battery as energy storage element

This paper presents an equivalent circuit based small signal model for a bi-directional dual half bridge (DHB) DC/DC converter. This converter is applied in a fuel cell vehicle that uses battery as an energy storage element to provide desired management of the power flows. The developed dynamic model is not only a deeper understanding of the physical insight of DHB topology, but guidance for the regulator design of DHB converter. Circuit measurements are provided to verify the accuracy of the small signal model. The current programmed control effectively removes two poles from the loop gain, which significantly simplifies the design of the feedback network. Finally, a power management control method is proposed to realize cold start and load leveling for fuel cell vehicle propulsion system.