Multi-port Converter Used In Fuel Cell Electric Vehicles

With the progress and the development of the automobile industry, people’s demand on the traditional energy is being greatly increased. Years of exploitation and utilization has been causing a severe shortage of traditional energy and increasingly heavier environmental pollution. Development and utilization of new energy has been being the most effective approach to solve the environmental pollutionand energy crisis. Fuel cell, as a representative of the new energy, whose reactant is hydrogen and emission is only water, has no pollution to the environment. Under this background, fuel cell electric vehicles have been developed rapidly.In this paper, the fuel cell vehicles power system is studied. The dynamic response of fuel cell is slow, and it can t store energy. In order to get stable electricity, the fuel cell power system needs to be equipped with auxiliary energy devices which can cooperate with fuel cells. Using a multiport converter instead of many single input single output converters can simplify the structure and reduce the cost, improve overall performance of the system. Therefore it is necessary to study deeply.This paper places emphasis on the research of the multiport converter. The basic principle of fuel cell power generation device and the characteristics of various energy storage devices are introduced in this paper. A new energy power supply system architecture based on multi-port converters is introduced. After comparation, the triple active bridge converter is choosed as the research object of this paper. The working principle of the converter is analyzed; the power transmission equation is deduced; In order to improve the work efficiency of the converter, the condition to realize soft switching of this converter is analyzed.The energy management strategy of fuel cell-super capacitor has been studied. According to the characteristics of the fuel cell and super capacitor, According to the power output characteristics, choose instantaneous power compensation management strategy, to realize the complementary advantages of fuel cell and super capacitor. For start, uniform, braking condition, one port of the converter is in the idle state, this paper puts forward an idling port control strategy, which make the port idle only by the control strategy, then reduce the use of mechanical components.Finally, this paper builds500W prototype validates by experiment. The detailed design process of the converter is given. The experimental results show that the circuit design is reasonable, soft switch analysis is correct, idling port control strategy is effective.