An Innovative Silicon Carbide (SiC) 6-KV, 1-KA Gate Turn Off (GTO) Thyristor

A high-voltage, high-current, SiC power switch is required by the existing utility infrastructure and its need to interconnect renewable energy sources to the grid (such as wind and solar photovoltaic). Renewable energy sources require new types of equipment with challenging issues not usually borne by the utility industry, including severe constraints on size, weight, and cost. This project will develop a 6-kV, 1-kA SiC gate turn-off (GTO) thyristor of innovative design. The GTO, which combines low losses with excellent switching performance, is the best device for wide adoption by the utility industry, where multi-megawatt applications are common. Moreover, the SiC GTO will be scalable to much higher voltages than practically any other device made from silicon or SiC, thereby enhancing its usefulness for future utility applications. Phase I will set the specification, scale the design to meet the specification, select high quality low-defect substrates to eliminate the only significant reliability concern with SiC bipolar devices (like the GTO), and grow and characterize the critical GTO stack. Commercial Applications and other Benefits as described by the awardee: A revolution in the supply of renewable energy sources has created a technology need for smaller, more efficient, and lower cost grid-connected inverters. The SiC GTO should reduce or eliminate series-connected devices in grid-connected inverters for medium-voltage application, leading to an opportunity to manufacture bipolar products for the significant medium-voltage utility and renewable energy markets. Wind and PV alone have attracted over $1 billion of sales in the last five years.