Impact of the modularity on the efficiency of Smart Transformer solutions

Abstract

Abstract-Due to the possibility to drastically reduce the Solid State Transformer (SST) volume and weight, its use is becoming a reality in traction and wind power plant applications, while, in the electric distribution system, it is still considered futuristic. A SST, with managerial role in the electric distribution grid, is generally called Smart Transformer (ST). Unfortunately the low efficiency, the low reliability and the high cost still act as barriers for its widespread use in the real world. This paper focuses on the impact of a modular design, by benchmarking different ST topologies. Moreover, the paper provides guidelines on how to choose the semiconductor modules and assessments on how the choice affects the efficiency of the ST.

The effect of a constant power load on the stability of a smart transformer

“…1, the scenario investigated in this work is shown. It is implemented with a Smart Transformer (ST) [4], that can be composed by one or more energy conversion stages, i.e. one or more power converters, some loads and some DPGSs directly connected to the low voltage side of the ST.…”

Smart Transformer reliability and efficiency through modularity

“…This can be simplified and leads to the efficiency in dependence of the load current (8) and the efficiency in dependency of the voltage (9).…”

“…The reliability of the ST is limited by the thermal stress for the power semiconductors caused by heating up and cooling down, which has been investigated for STs in the distribution system in [8]. A possible concept for the target of high efficiency is a modular design of the ST by using power semiconductors rated for lower voltage and current [9]. In partial load operation, the control can be used to optimize the conflicting goals between high efficiency and low thermal stress for the power semiconductors, realized by active thermal control [10].…”