Conference

Over the last decades, the development of power electronic systems was mainly targeting higher power densities r and a reduction of costs. An increase of the conversion efficiency h was only indirectly required, as the surface area available for power loss dissipation decreases with decreasing converter volume. However, due to environmental concerns, high efficiency is more and more important, so that today at least two design requirements, i.e. high power density and high efficiency, have to be met at the same time. This results in a multi-objective design optimisation, where a best possible compromise must be found between the two conflicting criteria.

Based on multi-domain converter models, an optimal mapping of the design parameters into the System Performance Space could be performed. There, different design criteria (e.g. r, h, etc.) could be considered and the best compromise of the system level performances could be determined. With single objective optimisations, the maximal achievable efficiency and the maximal achievable power density can be identified for a given set of technologies as has been shown for telecom DC/DC converters and PFC rectifiers.

By simultaneously optimising the efficiency and the power density with different weights, a performance limit and/or Pareto-Front could be determined in the r-h -plane. The Pareto-Front directly indicates for example the maximal achievable efficiency for a required power density.

In this paper, Pareto-Fronts are calculated for single-phase telecom PFC rectifiers, DC/DC converters and power supply modules in the power range of a few kilowatts. Based on the calculations, the efficiency and power density limits of the different topologies as well as the resulting limitations in the r-h-surface are discussed and the sensitivity of these limitations on different technologies as for example core materials, semiconductor technologies (SiC/GaN) or cooling concepts is explained. Furthermore, the extension of the Pareto-Front to a multidimensional Pareto-Plain by also considering for example weight, costs, reliability and/or EMI issues in the optimisation is discussed.