Otimização do Dual Active Bridge trifásico aplicada a veículos elétricos

Abstract

In times of change, the world thinks of better forms of continuing to benefit from the planet’s natural resources. Thus, electric vehicles emerge as an alternative for the maintenance and growth of quality of life, while also maintaining the fast and convenient means of transportation offered by cars. However, for that to happen, it is necessary to assure a better use of energy, be it in electrical form or not. Therefore, in this work, it is carried out an optimization of a bidirectional isolated DC-DC converter used in such vehicles. A modified version of the three-phase Dual Active Bridge (DAB) was used for the implementation of this converter. This modification is carried out in order to fulfill the need of increasing the converter efficiency for a low voltage and high power busbar without paralleling the semiconductors. The modification works with the addition of another three transformers and two three-phase bridges on the low voltage side. In the modeling and optimization process, it is noticed that the changes in various parameters influence the operation of the converter and, therefore, its volume and efficiency. The criterion for the determination of the best design is the smallest volume with higher efficiency. The process of obtaining such design justifies the use of the modified version of the DAB. The DAB series inductance, essential to the transfer of energy, is the transformer’s own leakage inductance, which reduces the volume of the magnetics. A prototype is built for the experimental validation of the constructive improvements. This work then presents a description how the prototype was assembled, followed by the prototype’s efficiency curves and thermal images and, finally, it presents the design of the current controller and its results. This research is part of project HELENE, which is developed in the laboratories of KDEE Kassel University – Germany.