Design and control of bi-directional DC/DC converter for 30kW fuel cell power system

Fuel cell (FC) power system is considered as an alternative energy power generation system in the future. This paper studies the bidirectional DC/DC converter for a 30kW three-phase fuel cell power system. The FC power system is sensitive to load characteristics in stand-alone mode, because rapid change or unbalance of the three-phase load will endanger the safety and expectancy of fuel cell. The bidirectional DC/DC converter with energy storage component is used to provide the dynamic power to avoid fast changing in fuel cell output. In addition, it acts as DC bus capacitors to absorb the low frequency current ripple. Therefore, fuel cell is separated from the low frequency current ripple and large DC bus electrolytic capacitors can be eliminated. Through investigating topology of the bidirectional DC/DC converter, three-level bidirectional DC/DC converter (TL-BD) is used for the 30kW fuel cell power system. The design and control of the TL-DB is described. TL-DB with its control strategy is verified by the experimental results.