1 kV, 10-kW SiC-Based Quadruple Active Bridge DCX Stage in a DC to Three-Phase AC Module for Medium-Voltage Grid Integration

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

Research output: Contribution to journalArticlepeer-review

11 Scopus Citations

Abstract

Interfacing low voltage (LV) dc to medium voltage (MV) three-phase ac grid is often based on series-stackable modular converter architectures. To minimize energy storage requirements, it is advantageous to employ a quadruple active bridge (QAB) stage operating as a “dc transformer” (DCX) in each stackable module. The QAB stage offers three isolated dc link voltages, which then allow for flexible stacking of three single-phase dc-to-ac inverter stages. Each of the module phases processes a pulsating power having a component at twice the line frequency. This presents a challenge in maintaining zero voltage switching (ZVS) on the secondary sides of the QAB during low-power portions of the line cycle. This paper is focused on the design of the QAB stage. A detailed analysis of ZVS switching waveforms is presented, including effects of nonlinear device capacitances. It is shown how ZVS can be achieved at all times using a relatively small circulating current provided by the magnetizing inductance of the high-frequency transformer. Analytical expressions are given for the optimal values of the magnetizing inductance and the dead times of the QAB primary and secondary bridges. The approach is verified by experimental results on a 1 kV, 10 kW SiC-based prototype, demonstrating a relatively flat efficiency curve with a peak efficiency of 97.1% at 75% load.

Original languageAmerican English
Pages (from-to)14631-14646
Number of pages16
JournalIEEE Transactions on Power Electronics
Volume37
Issue number12
DOIs
StatePublished - 2022

Bibliographical note

Publisher Copyright:
IEEE

NREL Publication Number

  • NREL/JA-5D00-83958

Keywords

  • Bridge circuits
  • dual active bridge
  • Inductance
  • Inverters
  • Magnetic switching
  • medium voltage ac
  • modular dc-to-ac inverters
  • photovoltaic power systems
  • quadruple active bridge
  • solid-state transformers
  • Switches
  • Transformers
  • zero voltage switching
  • Zero voltage switching

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