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Title: DISTINCT: Diversity in Solar Talent Through INnovative Curriculum and Training: An Integrated Research and Education Approach towards Creating Diversity and Advancing Utility-Scale Solar Technology

Abstract

The DISTINCT project research objective is to develop an innovative N-port power converter for a utility-scale PV system that is modular, compact and cost-effective and that will enable the integration of a high-frequency, high-voltage solid-state transformer. The novelty of the proposed research is the electrical power conversion architecture using an N-port converter system that replaces the output 60Hz transformer with an integrated high-frequency low-weight solid-state transformer reducing power electronics and BOS costs to meet SunShot goals through modularity and direct high-voltage interconnection. A challenge in direct integration with a 13.8kV line is the high voltage handling capacity of the converters combined with high efficiency operation. The front-end converter for each port is a Neutral-Point Clamped (NPC) Multi-Level dc-dc Dual-Active Bridge (ML-DAB) which allows Maximum Power Point Tracking (MPPT). The integrated high frequency transformer provides the galvanic isolation between the PV and grid side and also steps up the low dc voltage from PV source. Following the ML-DAB stage, in each port, is an inverter with H-bridge configuration or NPC configuration. N number of NPC inverters’ outputs are cascaded to attain the per-phase line-to-neutral voltage to connect directly to the distribution grid (i.e. 13.8 kV). The cascaded inverters have the inherentmore » advantage of using lower rated devices, smaller filters and low Total Harmonic Distortion (THD) required for PV grid interconnection. Our analysis and simulation results show improved performance on cost, efficiency, service life with zero downtime and THD. A comprehensive control scheme is presented to ensure the maximum power from each port and each phase are sent to the grid. A functional prototype of a 2-port converter with ML-DAB and cascaded H-bridges has been designed, built, and tested in a laboratory setup to verify the target technical metrics. The N-port converter system due to its modular structure with individual control per port can be easily adapted to integrate functionalities that go well beyond the conventional grid support functions and mitigates impacts of forecasted fast ramp downs or ramp ups and single-fault conditions by automatic reconfiguration of the output.« less

Authors:
 [1]
  1. Univ. of Texas, San Antonio, TX (United States)
Publication Date:
Research Org.:
Univ. of Texas, San Antonio, TX (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Solar Energy Technologies Office (EE-4S)
OSTI Identifier:
1419422
Report Number(s):
FinalTechnical-Report
DOE Contract Number:
EE0006323
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION

Citation Formats

Krishnaswami, Hariharan. DISTINCT: Diversity in Solar Talent Through INnovative Curriculum and Training: An Integrated Research and Education Approach towards Creating Diversity and Advancing Utility-Scale Solar Technology. United States: N. p., 2018. Web. doi:10.2172/1419422.
Krishnaswami, Hariharan. DISTINCT: Diversity in Solar Talent Through INnovative Curriculum and Training: An Integrated Research and Education Approach towards Creating Diversity and Advancing Utility-Scale Solar Technology. United States. doi:10.2172/1419422.
Krishnaswami, Hariharan. Mon . "DISTINCT: Diversity in Solar Talent Through INnovative Curriculum and Training: An Integrated Research and Education Approach towards Creating Diversity and Advancing Utility-Scale Solar Technology". United States. doi:10.2172/1419422. https://www.osti.gov/servlets/purl/1419422.
@article{osti_1419422,
title = {DISTINCT: Diversity in Solar Talent Through INnovative Curriculum and Training: An Integrated Research and Education Approach towards Creating Diversity and Advancing Utility-Scale Solar Technology},
author = {Krishnaswami, Hariharan},
abstractNote = {The DISTINCT project research objective is to develop an innovative N-port power converter for a utility-scale PV system that is modular, compact and cost-effective and that will enable the integration of a high-frequency, high-voltage solid-state transformer. The novelty of the proposed research is the electrical power conversion architecture using an N-port converter system that replaces the output 60Hz transformer with an integrated high-frequency low-weight solid-state transformer reducing power electronics and BOS costs to meet SunShot goals through modularity and direct high-voltage interconnection. A challenge in direct integration with a 13.8kV line is the high voltage handling capacity of the converters combined with high efficiency operation. The front-end converter for each port is a Neutral-Point Clamped (NPC) Multi-Level dc-dc Dual-Active Bridge (ML-DAB) which allows Maximum Power Point Tracking (MPPT). The integrated high frequency transformer provides the galvanic isolation between the PV and grid side and also steps up the low dc voltage from PV source. Following the ML-DAB stage, in each port, is an inverter with H-bridge configuration or NPC configuration. N number of NPC inverters’ outputs are cascaded to attain the per-phase line-to-neutral voltage to connect directly to the distribution grid (i.e. 13.8 kV). The cascaded inverters have the inherent advantage of using lower rated devices, smaller filters and low Total Harmonic Distortion (THD) required for PV grid interconnection. Our analysis and simulation results show improved performance on cost, efficiency, service life with zero downtime and THD. A comprehensive control scheme is presented to ensure the maximum power from each port and each phase are sent to the grid. A functional prototype of a 2-port converter with ML-DAB and cascaded H-bridges has been designed, built, and tested in a laboratory setup to verify the target technical metrics. The N-port converter system due to its modular structure with individual control per port can be easily adapted to integrate functionalities that go well beyond the conventional grid support functions and mitigates impacts of forecasted fast ramp downs or ramp ups and single-fault conditions by automatic reconfiguration of the output.},
doi = {10.2172/1419422},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Feb 05 00:00:00 EST 2018},
month = {Mon Feb 05 00:00:00 EST 2018}
}

Technical Report:

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