On-board Bi-directional Electric Vehicle Charging

Project Term:
04/09/2018 - 04/08/2022

Critical Need:

Electricity generation currently accounts for ~40% of primary energy consumption in the U.S. and continues to be the fastest growing form of end-use energy. Power electronics condition, control, and convert electrical power in order to provide optimal conditions for transmission, distribution, and load-side consumption. Most of today’s power electronics have limitations to their performance, temperature resilience, and size due to the circuit topology and semiconductor power devices used. Emerging semiconductor devices such as those based on wide-bandgap materials — along with transformative advances in circuit design and system architecture — present opportunities to dramatically improve power converter performance while reducing size and weight. Development of advanced power electronics with unprecedented functionality, efficiency, reliability, and form factor will help provide the U.S. a critical technological advantage in an increasingly electrified world economy.

Project Innovation + Advantages:

The University of California, Berkeley (UC Berkeley) and its project team will develop an on-board electric vehicle charger using a gallium nitride (GaN) based converter to improve power density and conversion efficiency. Conventional power converter topologies which primarily use magnetics (i.e. inductors and transformers) for energy transfer suffer from a tradeoff between efficiency and size. In this project, the team proposes a shift in traditional charger design to develop a bidirectional converter dominated by capacitor-based energy transfer. The team will leverage recent advances in GaN devices and new control techniques to produce a 6.6 kW converter with 15 times the power density and higher efficiency than currently achievable. The bidirectional flow means that the device can act to charge the electric vehicle or operate in a vehicle-to-grid manner to use the vehicle as short term energy storage. If successful, project developments could help reduce the size and complexity of electric vehicle power systems.

Potential Impact:

If successful, CIRCUITS projects will enable further development of a new class of power converters suitable for a broad range of applications including motor drives for heavy equipment and consumer appliances, electric vehicle battery charging, high-performance computer data centers, grid applications for stability and resilience, and emerging electric propulsion systems.


More robust power electronics that withstand higher operating temperatures, have increased durability, a smaller form factor, and higher efficiency will significantly improve the reliability and security of a resilient electrical grid.


Low cost and highly efficient power electronics could lead to more affordable electric and hybrid-electric transportation, greater integration of renewable power sources, and higher efficiency electric motors for use in heavy industries and consumer applications.


Electricity is the fastest growing form of end-use energy in the United States. High performance, low cost power electronics would enable significant efficiency gains across the economy, reducing energy costs for businesses and families.


ARPA-E Program Director:
Dr. Isik Kizilyalli
Project Contact:
Prof. Robert Pilawa
Press and General Inquiries Email:
Project Contact Email:


Oak Ridge National Laboratory
Delphi Automotive Systems, LLC
University of Arkansas
University of Illinois, Urbana Champaign

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