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

Abstract

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.

Authors:
 [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)
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE National Renewable Energy Laboratory (NREL), Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1484593
Report Number(s):
NREL/JA-5D00-72319
Journal ID: ISSN 0885-8969
Grant/Contract Number:  
AC36-08GO28308
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
IEEE Transactions on Energy Conversion
Additional Journal Information:
Journal Name: IEEE Transactions on Energy Conversion; Journal ID: ISSN 0885-8969
Publisher:
IEEE
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 24 POWER TRANSMISSION AND DISTRIBUTION; inverters; bridge circuits; voltage control; phase locked loops; maximum power point trackers; medium voltage; power transformer insulation

Citation Formats

Achanta, Prasanta K., Johnson, Brian B., Seo, Gab -Su, and Maksimovic, Dragan. A Multilevel DC to Three-phase AC Architecture for Photovoltaic Power Plants. United States: N. p., 2018. Web. doi:10.1109/TEC.2018.2877151.
Achanta, Prasanta K., Johnson, Brian B., Seo, Gab -Su, & Maksimovic, Dragan. A Multilevel DC to Three-phase AC Architecture for Photovoltaic Power Plants. United States. doi:10.1109/TEC.2018.2877151.
Achanta, Prasanta K., Johnson, Brian B., Seo, Gab -Su, and Maksimovic, Dragan. Mon . "A Multilevel DC to Three-phase AC Architecture for Photovoltaic Power Plants". United States. doi:10.1109/TEC.2018.2877151.
@article{osti_1484593,
title = {A Multilevel DC to Three-phase AC Architecture for Photovoltaic Power Plants},
author = {Achanta, Prasanta K. and Johnson, Brian B. and Seo, Gab -Su and Maksimovic, Dragan},
abstractNote = {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.},
doi = {10.1109/TEC.2018.2877151},
journal = {IEEE Transactions on Energy Conversion},
number = ,
volume = ,
place = {United States},
year = {Mon Oct 22 00:00:00 EDT 2018},
month = {Mon Oct 22 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on October 22, 2019
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