High power density DC-DC converter

This project is conducted in collaboration with the BMW Group and the Technical University of Munich.

Problem statement: 

Currently, for AC charging of electric vehicles, chargers located inside the vehicle are connected to an external charging station. Due to the increasing spread of DC charging points, the importance of AC charging in public places is decreasing more and more. In order to save costs in vehicle manufacturing as well as installation space, it is therefore desirable to remove the on-bord charger from the vehicle and integrate it into the charging cable alternatively.

The charger contains a power factor correction (AC-DC stage) and an isolated DC-DC converter. For the latter, air-cooled with a maximum power transfer capability of 11 kW, a power density of approximately 10 kW/l should be achieved. Novel wide-bandgap semiconductors, such as SiC and GaN, are a key enabler for such high power densities due to their superior electrical properties. Optimized passive components (capacitors, magnetics) as well as advanced packaging are additionally required.


Project description: 

To achieve the required high integration, a converter design optimized in terms of efficiency η and power ρ density is needed. Since these two properties usually contradict each other in power electronic converter systems, a multi-objective Pareto optimization shall be performed.

The aim of this work is the implementation of such an optimization routine to identify the application-specific optimal converter design. Unlike existing approaches, special emphasis is put on the evaluation of integrated magnetics and innovative packaging as well as on the application of advanced modulation schemes to increase the efficiency and power density. In order to evaluate as many different designs as possible, special attention is paid to an efficient implementation of the calculation routine.