The evaluation of a modular solid state transformer and low-frequency distribution transformer under daily loading profile

摘要

The effect of several modular approaches to the design, on the efficiency and size of a Solid State transformer (SST) are investigated. The modular approaches are evaluated for the case of 400 kVA, 10 kV/0.4 kV solid state transformers, considering the daily loading profile of the distribution network. The SST is compared to an equally rated low-frequency transformer (LFT) in terms of efficiency, volume and weight. It is shown that advantage can be taken of the modular approach to improve the light load efficiency of the SST, while at peak loading the SST's efficiency is 3% lower than that of the LFT. By increasing the number of modules and the switching frequency of the DC-DC converter stage, the weight of the SST can be reduced to 50% and its volume reduced to 33% that of the LFT.