Cascaded Quadruple Active Bridge Structures for Multilevel DC to Three-Phase AC Conversion

Brian Johnson, Dragan Maksimovic, Prasanta Achanta

Research output: Contribution to conferencePaper

5 Scopus Citations


This paper introduces a multilevel architecture comprised of interconnected dc to three-phase ac converter units. To enable series connected operation, each converter unit contains a quadruple active bridge (QAB) converter that provides isolation between the dc side and each of the three ac sides. Since each converter unit transfers dc-side power as constant balanced three-phase power on the ac side, this implies instantaneous input-output power balance and allows elimination of bulk capacitive energy storage. In addition to minimizing required capacitance, the proposed approach simultaneously enables simplified dc-link controllers amenable to decentralized implementation, supports bidirectional power transfer, and exhibits a modular structure to enhance scalability. Isolation provided by the QAB allows a wide range of electrical configurations among multiple units in various dc-ac, ac-dc or ac-ac applications. In this paper, the focus is on series connections on the ac side to emphasize multilevel operation, and the approach is experimentally validated in a dc-ac system containing two cascaded converter units.
Original languageAmerican English
Number of pages5
StatePublished - 2018
Event2018 IEEE Applied Power Electronics Conference and Exposition (APEC) - San Antonio, Texas
Duration: 4 Mar 20188 Mar 2018


Conference2018 IEEE Applied Power Electronics Conference and Exposition (APEC)
CitySan Antonio, Texas

NREL Publication Number

  • NREL/CP-5D00-68964


  • bridge circuits
  • capacitance
  • capacitors
  • energy storage
  • inverters
  • power system dynamics
  • voltage control


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