Design optimization of power electronic transformers in traction applications

Sandeep Kumar Chowdhury*, Hiroyasu Kobayashi, Keiichiro Kondo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


To increase efficiency and reduce weight of low frequency traction transformers (LFTs), many studies have been dedicated to the study and design of power electronic transformers (PETs). Most of these studies have focussed on 16.7 Hz traction systems and a few on 50/60 Hz systems. PETs offer several degrees of freedom to the designer such as configuration and modulation of power stages, switching frequency, magnetic material etc., which are evaluated based on given specifications to meet the objectives of maximum power density and efficiency. This paper presents a detailed analysis of efficiency and power density of each power stage in a PET with respect to its design parameters. A design methodology is outlined to replace an LFT with an optimally designed PET. To elucidate the design process, the considered case is a 4.16 MW transformer supplied by a 25 KV, 60 Hz catenary for a Shinkansen series-700. The configuration of the PET considered is of the indirect type with a cascaded H-bridge as the AC/DC stage interfacing the catenary and a set of parallelly connected DC/DC converters at the output. The best obtained efficiency is 97.7% with a weight of 1.69 tonnes which is significantly higher than that of the LFT.

Original languageEnglish
Pages (from-to)674-684
Number of pages11
JournalIEEJ Journal of Industry Applications
Issue number6
Publication statusPublished - 2020 Nov 1


  • American Wire Gauge (AWG)
  • Dual Active Bridge (DAB)
  • Medium Frequency Transformer (MFT)
  • Series Resonant Converter (SRC)
  • ZVS/ZCS (Zero Voltage/Current Switching)

ASJC Scopus subject areas

  • Automotive Engineering
  • Energy Engineering and Power Technology
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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