Optimal design of medium-frequency transformers for solid-state transformer applications

One of the most challenging problems of the electrical engineering in recent years is to replace conventional low-frequency distribution transformers with Solid-State Transformers (SSTs). The SST advantages make future smart grids flexible and cost effective. However, due to some main drawbacks such as low efficiency, it is not adopted in the distribution systems yet. In this paper, optimal design of Medium Frequency Transformers (MFTs) for a 20/0.4 kV 315 kVA solid-state transformer is done. The objective is to maximize the efficiency (η) and the power density (ρ), and to minimize weight of the MFT. The designed MFT reaches the efficiency > %99.70 and the power density > 13 kW/dm
³
.