Single-stage reconfigurable DC/DC converter for wide input voltage range operation in HEVs

This paper proposes a single-stage reconfigurable topology [1] for an isolated DC/DC converter that supplies the 12V power net from a HV-battery pack in hybrid and electric vehicles. The proposed topology solves the problem of reduced converter efficiency in the upper range of HV-battery voltages. The converter is based on the ZVT phase shift full bridge DC/DC converter that is depending on the instantaneous value of battery voltage reconfigured into the push-pull converter. The ZVT phase shift configuration covers upper range of input voltages whereas it is reconfigured into the less efficient, hard-switching, push-pull configuration to cover the lower range. The point of reconfiguration is chosen to maximize the average efficiency according to the histogram of HV-battery voltage during typical driving cycle. Experimental validation of the proposed converter and the efficiency improvement is also presented.