Researchers at North Carolina State University have created a high-voltage, high-frequency silicon carbide (SiC) power switch that they say could cost significantly less than similarly rated SiC power switches.

Their findings could lead to applications in the power industry—especially in power converters, such as medium-voltage drives, solid state transformers and high-voltage transmissions and circuit breakers.

Wide-bandgap semiconductors, such as SiC, show considerable potential across a range of devices because of their capability to work efficiently at higher voltages. Currently, however, their high cost impedes their widespread adoption over the prevailing workhorse and industry standard—insulated-gate bipolar transistors (IGBT) made from silicon—which generally work well but incur large energy losses when they are turned on and off.

Insert image here:The switch is able to operate over a wide range of temperatures and frequencies due to its proficiency in heat dissipation. Image credit: NCSU.power rating of 15 kilovolts (kV) and 40 amps. It requires only one gate signal to turn it on and off, making it simple to implement and less complicated than IGBT-series connection-based solutions. The switch is also able to operate over a wide range of temperatures and frequencies due to its proficiency in heat dissipation, a critical factor in power devices.

“Today, there is no high-voltage SiC device commercially available at voltage higher than 1.7 kV,” says Alex Huang, professor of electrical and computer engineering. “The FREEDM Super-Cascode solution paves the way for power switches to be developed in large quantities with breakdown voltages from 2.4 kV to 15 kV.”

According to Huang, the new SiC power switch could cost approximately one-half that of conventional high-voltage SiC solutions. Beyond the lower cost, the switch maintains the SiC device’s high-efficiency and high-switching-speed characteristics. In other words, it doesn’t lose as much energy when it is turned on and off.