Efficiency Comparison of Solid-State Transformer and Low-Frequency Power Transformer

Abstract

This paper compares the efficiency of a solid-state transformer based on matrix converter and a low-frequency conventional transformer. Solid-state transformers can perform the functions of a low-frequency power transformer and also provide additional functionalities for the grid. However, efficiency is an issue when it comes to the replacement of a conventional transformer by a solid-state transformer. Low-frequency conventional power transformers have very high efficiencies. With the development of SiC devices and the nanocrystalline material for the high-frequency transformer, which promise high power densities, it has become possible to construct solid-state transformers with high efficiency. This paper compares the efficiency of a solid-state transformer bsed on matrix converter and a conventional low-frequency power transformer both rated 500 kVA for the grid voltage ratios 33 kV/11 kV and 11 kV/430 V.