Sometimes a disturbance occurs within the charger itself. A single EV charger contains three power modules working together to convert and control charging power. The ORNL team created another algorithm allowing the converter to detect and adjust to an internal failure instead of turning off.
Kim and his team developed new algorithms to manage the operating parameters of the power electronic converters that are the keystone of EV charging hardware. These converters are designed to shut off when power flow strays outside a standard range. If a small fault in the electric grid causes a fleeting drop in voltage, EV charging stops. Similarly, the failure of one internal component can also shut everything down. Reactivating these chargers often requires maintenance, causing significant downtime at unmanned stations.
There are broader benefits, too. If a grid fault causes many EV chargers to disconnect during high-power fast charging, the voltage level in the power grid can suddenly increase. This condition may damage other unprotected electrical equipment. For this reason, ride-through capability protects not only the charger but the broader electric grid.
Researchers also developed a new, multilayered approach for control and communication across the kind of larger EV charging system that resembles a gas station with many pumps: A systemwide controller is automatically notified of problems at individual chargers. It can then alter equipment settings for the best customer charging experience.
This research fits into a larger project with partners in the Pacific Northwest and Idaho that includes automatic management of charging vehicle fleets, such as delivery or long-haul trucks, as well as monitoring for potential cyberattacks. The station controller could control vehicle charging order and charging rates, balancing energy costs with cargo priorities.
After identifying the major challenges, ORNL researchers found solutions to address two key causes of charger failure—the first triggered by voltage shifts in the electric grid, and the other originating within the charger itself.
Other ORNL researchers contributing to the ongoing project include Michael Starke, Madhu Chinthavali, Benjamin Dean and Steven Campbell. The research is funded by the Vehicle Technologies Office under the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy, leveraging the capabilities in ORNL’s Grid Research Integration and Development Center (GRID-C). The latter develops technological solutions to advance the dynamic and efficient interaction of the electric delivery system with buildings and vehicles.
ORNL researchers are developing algorithms and multilayered communication and control systems that make electric vehicle chargers operate more reliably, even if there is a voltage drop or disturbance in the electric grid. Credit: Andy Sproles/ORNL, U.S. Department of Energy.
University of Tennessee-Battelle manages ORNL for the U.S. Department of Energy’s Office of Science, the single largest supporter of basic research in the physical sciences in the United States. The Office of Science is working to address some of the most pressing challenges of our time. For more information, visit energy.gov/science.