A Study on High Frequency Transformer Design in Medium-voltage Solid-state Transformers

High switching frequency (HF) operation of solid-state transformers (SSTs) reduces the weight and volume of magnetic parts. Yet in medium-voltage (MV) SSTs, electrical insulation becomes a great concern and demands extra spacing. To resolve the issue, resistive shielding technique is considered in this paper to mitigate the threat of partial discharge. In addition, geometric shaping is applied to alleviate local electrical field. On top of the insulation and size requirements, HF transformer design should also consider skin effect and other effects induced by ac electromagnetic field. This paper is meant to develop a planar transformer for a MV SST, taking all critical factors into account. 2-d finite element analysis is adopted as main research and conceptual verification method.