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Title: A Multilevel DC to Three-phase AC Architecture for Photovoltaic Power Plants

Journal Article · · IEEE Transactions on Energy Conversion
 [1];  [2];  [3];  [1]
  1. Univ. of Colorado, Boulder, CO (United States)
  2. Univ. of Washington, Seattle, WA (United States)
  3. National Renewable Energy Lab. (NREL), Golden, CO (United States)
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This study presents a photovoltaic (PV) inverter architecture composed of stackable dc to three-phase ac converter blocks. Several such blocks, each containing a converter power stage and controls, are connected in series on their ac sides to obtain transformerless medium-voltage ac interfaces for PV power plants. The series-connected structure is made possible by a quadruple active bridge dc-dc converter that provides isolation between the PV input and each of the three ac-side phases within each block. Furthermore, since incoming PV power is transferred as constant balanced three-phase ac power, instantaneous inputoutput power balance bypasses the need for bulk energy storage. To streamline implementation and maximize system scalability and resilience, decentralized block-level controllers accomplish dc-link voltage regulation, maximum power point tracking, and ac-side power sharing without centralized means. The proposed architecture is validated by simulations of a PV string to mediumvoltage ac system consisting of six blocks and on a proof-of-concept hardware prototype that consists of three cascaded converter blocks.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States); Univ. of Washington, Seattle, WA (United States)
Sponsoring Organization:
USDOE National Renewable Energy Laboratory (NREL), Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
Grant/Contract Number:
AC36-08GO28308; EE0008346
OSTI ID:
1484593
Alternate ID(s):
OSTI ID: 2283493
Report Number(s):
NREL/JA-5D00-72319
Journal Information:
IEEE Transactions on Energy Conversion, Vol. 34, Issue 1; ISSN 0885-8969
Publisher:
IEEECopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 31 works
Citation information provided by
Web of Science

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