Cascaded Quadruple Active Bridge Structures for Multilevel DC to Three-Phase AC Conversion
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- University of Colorado
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.
- Research Organization:
- National Renewable Energy Laboratory (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S); USDOE Office of Energy Efficiency and Renewable Energy (EERE), NREL Laboratory Directed Research and Development (LDRD)
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 1441159
- Report Number(s):
- NREL/CP-5D00-68964
- Country of Publication:
- United States
- Language:
- English
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