News: Microelectronics
12 December 2022
Virginia Tech gains $1.5m, four-year NSF grant to research optically driven power switches
Principal investigator Yuhao Zhang and three other professors from the Bradley Department of Electrical and Computer Engineering have been awarded a $1.5m grant from the US National Science Foundation’s Electrical, Communications and Cyber Systems flagship program ASCENT (Addressing Systems Challenges through Engineering Teams), which is focused on future semiconductor technologies.
Zhang and his team are proposing what is reckoned to be a first-of-its-kind semiconductor technology that is optically driven for use in grid power electronics.
Key collaborators in the project include faculty from the Center for Power Electronics Systems (CPES) in Arlington and Blacksburg and the Center for Photonics Technology (CPT). Both of these research centers are based at Virginia Tech.
Working with Zhang (an expert in the areas of power electronics, micro/nano-electronic devices, and advanced semiconductor materials) are assistant professors Dong Dong and Christina DiMarino and associate professor Xiaoting Jia.
Dong is a faculty member of the Center for Power Electronics Systems with research expertise in power electronics and power conversion systems. DiMarino is also a member of that center’s faculty and has expertise in power electronics packaging. Jia is a faculty member of the Center for Photonics Technology with a background in fiber-based neural interfaces, nano-bio interfaces, and fiber sensors and devices.
The existing US power grid relies primarily on coal and natural gas to produce electricity. Furthermore, electricity generation is responsible for about 25% of greenhouse gas emissions. In an effort to reduce this environmental impact, the team will leverage the unique electronic and optical properties of ultra-wide-bandgap semiconductors that can withstand a very high electric field.
Most existing power switches are electrically driven, relying on the base drive current or the gate-drive voltage to turn the device on and off. As more renewable energies and higher power levels have been introduced into the grid structure, the high switching frequency needed has increased the risk of noise. In addition, stacking hundreds of devices to enhance power means that it is difficult for them to be driven synchronously.
Explaining the existing setbacks of electrical semiconductors and the potential for optically driven devices, DiMarino says that, when electrical noise occurs, devices can transition on and off very quickly (false triggering), which creates a disturbance. For multiple devices, the non-synchronous driving also will lead to false triggering. This can cause problems like short circuits and eventually system failure in the grid.
Optically driven semiconductors operate on the principle of photo-generation, using a light source from a laser fiber to turn the switch on and off. This approach provides more noise immunity because photons are used instead of electrons. The fast speed of light allows for an ideal synchronization for driving hundreds of devices, and the number of required electrical components can be reduced.
Implementing these devices into the semiconductor power grid would drastically simplify the complexity of grid-scale power, resulting in greatly improved scalability, efficiency, interactivity and resiliency, say the researchers.
Zhang recently published a review on the field of power semiconductors and power electronics in Nature Electronics in collaboration with faculty from the University of Cambridge and the University of Southern California.
“The power semiconductor market has reached $40bn and is forecasted to more than double that amount by the year 2030,” says Zhang. “Innovation in power semiconductors is a driver for energy savings in data centers, electric vehicles, and the electric grid. Therefore, it holds the key for realizing the unprecedented cuts in carbon dioxide for a greener and more sustainable environment.”
“Our department is very diverse and transdisciplinary,” says Zhang. “One unique thing about the department is that we are not just collaborating with individuals but also collaborating with different centers — in this case, CPES and CPT. These research centers add another opportunity to strengthen the bond,” he adds.
Each team member will contribute to different areas of the project at different stages throughout the four-year timeline. Zhang, Jia and Dong are all National Science Foundation CAREER Award winners and provide strong knowledge in their respective fields. DiMarino has received the Virginia Tech College of Engineering Outstanding New Assistant Professor Award and the DOE ARPA-E OPEN 2021 Award.
As part of the ASCENT grant, the team will provide educational opportunities to train future engineers in the areas of semiconductor technologies, optical systems, power electronics, and microelectronics. The researchers will partner with a team in electrical and computer engineering’s Major Design Experience, a two-semester senior design project course that gives students industry-like experience.
The team members also will add project-related curricula to their current undergraduate and graduate courses. With additional access to Center for Power Electronics Systems resources, students will have real-world learning experiences while interacting with industry professionals.
The researchers also plan to collaborate with the Center for the Enhancement of Engineering Diversity at Virginia Tech to introduce semiconductor, power electronics, and nanotechnology to students, particularly middle school and high school girls. The resulting summer camps will provide hands-on experiences of the new technologies.
Zhang is hopeful for the future of the grid based on the research being done, the technology being developed, and the training being provided to students — all focused in the area of semiconductors. “The advancements we are going to develop are for the next generation of power electronics,” he says. “If successful, the hope is that, in 10–20 years, we can have these devices built into the system.”
