Soft Switching Over the Entire Line Cycle for a Quadruple Active Bridge DCX in a DC to Three-Phase AC Module

Branko Majmunovic, Satyaki Mukherjee, Rahul Mallik, Soham Dutta, Gab-Su Seo, Brian Johnson, Dragan Maksimovic

Research output: Contribution to conferencePaperpeer-review

3 Scopus Citations

Abstract

This paper is focused on a transformer-isolated quadruple active bridge (QAB) dc-dc converter loaded by three full-bridge dc-ac inverters. The QAB functions as a DC trans-former (DCX) in the dc-to-three-phase ac module. The QAB outputs provide time-varying power at twice the line frequency, which presents challenges in maintaining zero voltage switching (ZVS) on the secondary sides during low-power portions of the line cycle. It is shown how ZVS can be achieved in a phase, even at zero-power transfer, using a relatively small circulating current provided by the magnetizing inductance of the high-frequency transformer. The approach is particularly effective in high-voltage applications using SiC MOSFETs, where reductions in switching loss outweigh additional conduction losses due to the circulating currents. A detailed analysis of ZVS switching waveforms at the zero power transfer is presented, including effects of nonlinear device capacitances. Analytical expressions are given for the optimal values of the magnetizing inductance and dead times of the QAB primary and secondary bridges. The approach is verified by experimental results on a 600 V, 4 kW prototype, demonstrating greater than 98.5% efficiency from 1 kW to 4 kW, with a peak efficiency of 99.0%. Compared to conventionally operated prototype, a 54% reduction in total loss is achieved at rated power.

Original languageAmerican English
Pages3464-3471
Number of pages8
DOIs
StatePublished - Mar 2020
Event35th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2020 - New Orleans, United States
Duration: 15 Mar 202019 Mar 2020

Conference

Conference35th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2020
Country/TerritoryUnited States
CityNew Orleans
Period15/03/2019/03/20

Bibliographical note

See NREL/CP-5D00-74449 for preprint

NREL Publication Number

  • NREL/CP-5D00-77553

Keywords

  • C2
  • quadruple active bridge
  • soft switching
  • zero voltage switching

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