Integrated Multi Mode Converter With Single Inductor for Fuel Cell Electric Vehicles

Fuel cell electric vehicles have batteries to mitigate problems such asthe inability to store energy, poor response speed, and low power density. In the conventional power conversion system, the fuel cell (FC) and battery can be connected to the output load via two independent converters, namely a unidirectional converter for powering with the FC and a bidirectional converter for powering and regenerating via the battery. The conventional converter has a simple structure; it achieves specific operating modes that are required in various driving situations. However, it has two inductors and many operating switches when both the FC and battery are simultaneously used. In addition, all the switches have high voltage stresses. These factors can degrade the overall power density and efficiency. Thus, an integrated converter with single inductor is proposed in this article. By employing a battery mode selection cell, the two converters can be integrated with only one inductor. Moreover, the number of operating switches is reduced during powering, and low voltage-rated semiconductor devices can be used. Therefore, the proposed converter can achieve a high power density and low conduction and core losses. The validity of the proposed converter was demonstrated by the experiments under various operating conditions.