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

Achanta, Prasanta K.; Johnson, Brian B.; Seo, Gab -Su; Maksimovic, Dragan

doi:10.1109/TEC.2018.2877151

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:

Achanta, Prasanta K. ^[1]; Johnson, Brian B. ^[2]; Seo, Gab -Su ^[3]; Maksimovic, Dragan ^[1]

Univ. of Colorado, Boulder, CO (United States)
Univ. of Washington, Seattle, WA (United States)
National Renewable Energy Lab. (NREL), Golden, CO (United States)

Publication Date:: Mon Oct 22 00:00:00 EDT 2018

Research Org.:: National Renewable Energy Laboratory (NREL), Golden, CO (United States); Univ. of Washington, Seattle, WA (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), Renewable Power Office. Solar Energy Technologies Office

OSTI Identifier:: 1484593

Alternate Identifier(s):: OSTI ID: 2283493

Report Number(s):: NREL/JA-5D00-72319
Journal ID: ISSN 0885-8969

Grant/Contract Number:: AC36-08GO28308; EE0008346

Resource Type:: Accepted Manuscript

Journal Name:: IEEE Transactions on Energy Conversion

Additional Journal Information:: Journal Volume: 34; Journal Issue: 1; 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.

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                    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.  https://doi.org/10.1109/TEC.2018.2877151

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                    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.  https://doi.org/10.1109/TEC.2018.2877151.  https://www.osti.gov/servlets/purl/1484593.

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@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       = 1,

  volume       = 34,

  place        = {United States},

  year         = {Mon Oct 22 00:00:00 EDT 2018},

  month        = {Mon Oct 22 00:00:00 EDT 2018}

}

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Figures / Tables:

Figure 1: The dc to three-phase ac block in (a) forms the foundation of the transformerless architecture in (b). The converter stack performs string-level MPPT on each PV string, while low-distortion waveforms are synthesized on the MVAC side.

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