20-kV GaN Switch Technology Demonstrated in High-Efficiency Medium-Voltage Building Block
Solid-state transformers and circuit breakers will enable a more agile and robust electrical grid. Research suggests that for widespread deployment of power electronics into grid-scale applications, semiconductor switches should consume less than 0.5% of the power. Although silicon carbide (SiC) technology is fast enough for grid applications, it exceeds the 0.5% requirement. Gallium nitride’s (GaN) greater efficiency (6x lower specific on-resistance than SiC) suggests the time has come to invest in GaN for power distribution. Considerable research has been done on lateral GaN power switching transistors but vertical GaN devices are at a relatively less mature stage. Reducing the power loss would incentivize the deployment of power electronics into generation, distribution, and consumption of energy resulting in significant energy savings and highly reliable operation. Each 3% improvement in efficiency for renewables (solar + wind) and high-power industrial applications translates to one-half a Quad of energy (approximately the energy from 4B gallons of gasoline) saved annually. Additionally the sub-microsecond switching speed of GaN will enable solid-state apparatus to process power in the 10–100 kHz range rather than 60 Hz. This will decrease the power electronics’ size and weight as every tenfold increase in frequency has been shown to reduce weight by more than fivefold.
Project Innovation + Advantages:
Virginia Tech will accelerate deployment of power electronics into grid-scale energy applications by developing 20 kV GaN devices integrated into a medium-voltage (MV) power module. For the GaN power devices, high-quality substrates and innovative growth techniques will be used to reduce the background impurity contamination in the thick layers needed to block 20 kV. The power module will be fabricated using three-dimensional packaging for improved thermal management and high-power density at 20 kV. The power module will enable the full potential of high-voltage, high-temperature, and fast-switching GaN devices in MV power converters for use in renewable energy grid-level applications and transportation.
The cornerstone of the program is the development of a 20 kV GaN switch delivered in a power module, integrated with gate drivers and protections, and produced as an MV building block.
The technology will position the U.S. to monopolize global GaN-based energy markets.
The technology accelerates deployment of power electronics into grid-scale energy applications, dramatically reducing energy consumption-related emissions.
Advancement in power electronics promises enormous energy efficiency gains throughout the U.S. economy.