Contents I. Introduction
With the gradual promotion of new energy vehicles such as hydrogen fuel cell vehicles [1], the global energy shortage and environmental problems have been weaken. Since the output voltage of the hydrogen fuel cell is limited by the cell voltage directly, it cannot supply power to the motor of the electric vehicle. In order to utilize the electric energy by the hydrogen fuel cell effectively, achieve stable power supply for variable load and ensure a certain voltage level, the DC converter must be used in parallel. The parallel structure is suitable for high power application and attracts more and more attentions from researches [2]-[3].
