Design of a Resonant Converter for a Regenerative Braking System Based on Ultracap Storage for Application in a Formula SAE Single-Seater Electric Racing Car

Abstract

Electric mobility can represent a game changing technology for the long-term sustainability of the transportation sector. Pursuing this target, a model to simulate an Electric Vehicle (EV) for Formula SAE Electric competition is herein proposed: all the subsystems of the EV and the hybrid storage of the Li-ion batteries and Ultra-Capacitors (UCs) are implemented, in order to store the kinetic energy of the regenerative braking in the storage system through the Kinetic Energy Recovery System (KERS). A bidirectional DC-DC resonant converter is herein applied to the KERS to manage the UC pack. The operational limits of the proposed system, keeping the soft-switching properties, are discussed, and the results show the capability of the converter to operate under resonant mode in both boost and buck mode. A drawback is the presence of high current peaks in the resonant inductor. The use of more than one converter in interleaving and the adoption of a suitable capability factor ensure the proper operation of the system.