The Advanced Power Electronics Design for Solar Applications (Power Electronics) funding program will help the industry develop new technology to improve the devices that serve as the critical link between solar photovoltaic (PV) arrays and the electric grid. Given that all solar PV-generated electricity must flow through a power electronic device, this presents an opportunity to innovate and discover new applications that lower costs, offer enhanced services for improved lifetime value, and lower grid integration costs. These hardware solutions aim to reduce PV plant lifetime costs, enhance capabilities for real-time PV power flow control, and enable increased amounts of solar energy on the nation’s electric grid. Several of the projects in this funding program examine solutions using silicon carbide. The Department of Energy announced selections for Power Electronics on April 18, 2018. Read the announcement.

On November 15, 2018, the Solar Energy Technologies Office hosted a kickoff meeting for its Power Electronics funding program. Download the presentations.

The funding program addresses two topic areas:

• In the first area, projects will focus on advancing inverter/converter technology that lowers lifetime costs by reducing upfront costs, extending product life, improving efficiencies and lowering manufacturing costs.
• In the second area, projects will explore enhanced grid integration capabilities, which include holistic power electronics designs that: integrate solar with other power flow devices like energy storage or reactive power devices, provide online operations and maintenance services that can detect and respond to fault events, or help to quickly recover from power outages.

Power Electronics projects will improve the reliability and resiliency of the nation’s electric grid by improving the interface point between solar and the grid. These new, cost-effective power electronics designs will make solar energy controllable and eventually dispatchable through resilient microgrids. Further, advanced solar power electronics will help to ensure customer reliability when there are high penetration levels of solar.

-- Award and cost share amounts are subject to change pending negotiations –

Topic Area 1: Lowering Cost and Improving Equipment Reliability

Project Name: Modular HF Isolated Medium-Voltage String Inverters Enable a New Paradigm for Large PV Farms
Location: Atlanta, GA
DOE Award Amount: $1,927,973
Awardee Cost Share: $497,016
Principal Investigator: Deepak Divan
Project Summary: This project will develop and validate a new inverter to significantly reduce the balance-of-system costs in larger commercial and utility-scale photovoltaic (PV) farms. The inverter realizes higher-value propositions such as dispatchability and dynamic grid support. The project uses a medium-voltage string inverter topology and a soft-switching solid state transformer, which can interconnect direct current from solar panel strings at 600 to 1000 volts to a standard utility distribution voltage of 4.16 kilovolts. The medium-voltage line will be fed from a standard utility substation that derives power from a 69-500 kilovolt transmission source, eliminating a 60 hertz transformer in the power path and resulting in both cost and efficiency savings.

Project Name:  PV Inverter Systems Enabled by Monolithically Integrated Silicon Carbide-Based Four Quadrant Power Switch
Location: Raleigh, NC
DOE Award Amount: $1,517,146
Awardee Cost Share: $381,887
Principal Investigator: Subhashish Bhattacharya
Project Summary: This project creates an ultra-high-density, low-cost power conversion device using a newly developed single die Silicon Carbide-based power semiconductor switch that can block voltage and carry current in all polarities or quadrants of the power switch. The proposed scalable power conversion device can enable single-stage power conversion and then be used as a building block for photovoltaic inverters to meet and exceed efficiency, reliability and power density targets when compared to conventional two-stage cascaded solutions.

Project Name: A Reliable, Cost-Effective Transformerless Medium-Voltage Inverter for Grid Integration of Combined Solar and Energy Storage
Location: Fayetteville, AR
DOE Award Amount: $2,765,138
Awardee Cost Share: $713,853  
Principal Investigator: Yue Zhao
Project Summary: This project aims to enhance PV plant reliability with significantly reduced lifetime costs for a high-density 300 kilowatt central inverter. It converts 1.5 kilovolt direct current output of the photovoltaic systems to 4.16 kilovolt alternating current without the use of bulky 60 hertz transformers. The proposed technology lowers the lifetime costs of Silicon Carbide inverters through the simultaneous electro-thermal design of the subsystem and the components of the inverter. This project establishes a basis for new innovations by addressing the challenge of multi-objective optimization while accounting for inverter cost and reliability constraints.

Project Name: Compact and Low-Cost Microinverter for Residential Systems
Location: College Park, MD
DOE Award Amount: $1,872,818
Awardee Cost Share: $498,876
Principal Investigator: Alireza Khaligh
Project Summary: This project aims to create a holistic design of microinverters using the emerging gallium nitride semiconductors combined with a novel circuit with reduced components and filters. The project models thermal stresses and their effect on reliability by using a multi-physics-based approach resulting in an improved assembly design. It is anticipated that the microinverter will yield over 250,000 hours of operation with no failures under consumer rooftop and commercial installation use conditions, while simultaneously achieving lower costs.

Project Name: Modular Wide-Bandgap String Inverters for Low-Cost Medium-Voltage Transformerless PV Systems
Location: Seattle, WA
DOE Award Amount: $2,837,106
Awardee Cost Share: $709,347
Principal Investigator: Brian Johnson
Project Summary: The proposed string inverter uses integrated circuit+control (C2) blocks, each comprised of a wide-bandgap-based power converter and local controller that can be assembled in a modular fashion to produce ultra-low-cost medium-voltage transformerless photovoltaic (PV) inverters. Each C2 block will be fabricated on high-voltage printed circuit boards with planar magnetics, such that automated manufacturing processes can be leveraged for maximum cost savings and throughput. This eliminates costly passive components and low-frequency transformers, substantially reducing electrical balance-of-system costs.

Project Name: Ultra Compact Electronlyte-Free Microinverter with Megahertz Switching
Location: Blacksburg, VA
DOE Award Amount: $1,031,317
Awardee Cost Share: $257,902  
Principal Investigator: Jason Lai
Project Summary: The objective of this project is to develop a cost-effective photovoltaic (PV) microinverter that fully utilizes the potential of wide-bandgap semiconductor devices, like gallium-nitride devices, which have shown potential of switching at megahertz frequencies. By operating the PV microinverter at such high frequencies, passive component size can be drastically reduced while still maintaining ultra-high efficiency of the microinverter. With the tallest component in the entire package measuring less than 0.2 inch, the potting compound material can be reduced by 80% as compared to typical designs with a one inch tall package, further reducing the cost of the product.

Topic Area 2: Enhanced Functionality for Grid Services

Project Name: Solar Power Electronics Modular Integrated Node Platform
Location: Encino, CA
DOE Award Amount: $2,496,150
Awardee Cost Share: $704,558
Principal Investigator: Robert Dawsey
Project Summary: This innovative power electronics platform combines solar power with stationary energy storage and electric vehicles to minimize installation costs and to optimize the use of solar energy. The project will develop advanced controls built on system awareness and communications, coupled with cloud-based analytics for optimized energy utilization. The platform leverages silicon carbide-based power electronics to provide high efficiency inverters, in addition to having controllable power flow between the distributed energy resources and the load.

Project Name: Multiport Autonomous Reconfigurable Solar Power Plant
Location: Oak Ridge, TN
DOE Award Amount: $2,500,000
Awardee Cost Share: $625,000  
Principal Investigator: Madhu Chinthavali
Project Summary: This project is developing an integrated system of modular power electronics devices that connect utility-scale solar power plants and energy storage with the high voltage direct current and alternating current distribution and transmission grid. This system, referred to as a multiport autonomous reconfigurable solar power plant, will introduce greater grid stability and enable continued operation under grid disturbances through advanced controls. It will also include a cyber-physical security layer for the controller that uses a combination of data-based and physics-based integrity checks to determine intrusions.

Project Name: Modular, Multifunction, Multiport, and Medium-Voltage Utility Scale Silicon Carbide PV Inverter  
Location: Austin, TX
DOE Award Amount: $2,999,400
Awardee Cost Share: $840,452  
Principal Investigator: Alex Q. Huang
Project Summary: This project is developing the next-generation utility-scale photovoltaic (PV) inverter referred to as a modular, multi-function, multiport, and medium-voltage utility-scale silicon carbide solar inverter. Called the M4 Inverter, it directly converts the direct current output of solar panels to medium-voltage alternating current, eliminating the bulky and costly low-frequency transformer. The inverter also has a direct current port to interface with an additional energy storage device. The device has multiple functionalities and can be used for reactive power support, fast frequency regulation, and peak power reduction, and enables synthetic inertia to be integrated into the inverter for grid support. Taken together, these advances will enable the inverter to drastically reduce the levelized cost of energy.

Learn more about the solar office's other funding programs.