Efficiency optimization of a single-phase boost DC-DC converter for electric vehicle applications

One of the main problems in autonomous electric vehicles is the energy storage, because a high autonomy and high power condition demand large mass, big volume and high cost of the storage unit. Consequently, in order to avoid power losses and to downsize the storage unit and the electric systems, the electric power train in the vehicle must be as efficient as possible. This paper proposes a methodology to optimize the efficiency of a DC-DC converter that interface the storage unit with the motor´s drive. In this way, with the purpose of increasing the efficiency, this methodology combines three techniques: 1) The use of low-loss components such as Si CoolMos, GaN and SiC diodes and Mosfets, and Multilayer Ceramic Capacitors, 2) a complete power loss analysis as a function of the switching frequency and a calculation method of core losses based on the approximation of Fourier Series, and 3) the Area Product Analysis of magnetic components. With this methodology, it is possible to achieve high efficiency and high power density, which is suitable for automotive applications. The methodology has been verified with a set of tests on a 1kW prototype. As a result of the proposed methodology, a power efficiency of 99% was experimentally obtained.