Towards virtual prototyping and comprehensive multi-objective optimisation in power electronics

Abstract

The constant demand for higher efficiency and power density and lower costs of power electronics systems could be met by application of new topologies and/or modulation schemes and future wide-band gap semiconductor technology. However, the performance of state-of-the-art systems also could be improved significantly by multi domain/objective optimisation, i.e. by assigning overall optimal values to the design variables in the course of the design process. In order to perform such an optimisation first a comprehensive mathematical model of the main converter circuit has to be established, including thermal component models and the measures for DM and CM EMI filtering. Based on this model, an optimisation for multiple objectives, as e.g. efficiency and power density, can be performed. The optimisation makes best use of all degrees of freedom of a design and also allows to determine the sensitivity of the system performance on base technologies like Figures of Merit of the power semiconductors or properties of the magnetic core materials. Furthermore, different topologies can be easily compared and inherent performance limits can be identified. In the paper, analytical approaches for designing the main functional elements of a power electronics converter are described and arranged to a linear design process in a first step. Moreover, the linking of the component models, i.e. of the electric, magnetic, thermal and thermo-mechanic design domains and an overall optimisation of the respective design variables based on the linked models is discussed. Finally, the coupling of the different domains and for example the utilisation of electrical equivalent circuits for implementing these couplings are investigated.