Development of a galvanically isolated DC-DC converter for auxiliary power supply for modular power electronic systems in the medium voltage range

The rapid expansion of energy production from renewable sources and the imperative shift towards decarbonization across various sectors of the economy, such as industry, mobility, and agriculture, increase the significance of power electronic systems in the medium voltage range. In this context, galvanically isolated, modular topologies stand out as of particular interest. These systems offer adaptability to the desired voltage and power specifications of diverse applications through the use of identical module types.
Crucial to the operation of these modules are auxiliary power supplies, including controllers, drivers, and sensors. However, the unique design of these modules and their interconnection present considerable challenges to the insulation strength of the auxiliary power supplies. Currently, suitable power supplies are hardly available commercially. Hence, the objective of this thesis is to develop a suitable auxiliary power supply for the power modules of a DC-DC converter with an isolation voltage of 8 kV.
For this purpose the DC-DC converter is designed and the final PCB design integrates the Half-Bridge LLC resonant converter with a Synchronous Rectifier topology controlled through feed-forward control. Achieving a high isolation range is realized by designing the transformer using contactless power transfer principles, yielding a notable coupling efficiency of 71.5%. The operation is examined through analytical and simulation analyses of component current waveforms, providing insights into component current stresses and losses within the converter system.