Takashi Nakamura, Executive Vice President
Rising global demand for electric power has propelled the innovation in energy-saving devices space. The alternative to silicon semiconductors - Silicon Carbide (SiC) Semiconductor - is promising; however, the material cost and high voltage resistance are hurdles to its adoption. To realize the true potential of SiC semiconductors, companies are vying to enhance circuit technology to manipulate high voltage at high speed and mounting technology to increase cooling efficiency. Fukushima SiC Applied Engineering Inc. claims to have successfully addressed these challenges and made SiC Semiconductors accessible for its clients. Not only that, the company is also promoting the diffusion of SiC to new application fields by proposing and demonstrating new ways to use SiC semiconductors.
To enhance circuit technology, the company used a simple series-connected circuit of SiC MOSFETs with no characteristic degradation by controlling the gates at ultra-high speed. This enabled the manipulation of ultra-high-voltage at high-speed switching, which otherwise would require significant cost and time for device development.
Fukushima also introduced direct-board mounting technology to improve cooling efficiency, thus making SiC semiconductors useful in high power operation. “With these technologies, ultra-high-speed, high-voltage high-power switches that could not be realized with semiconductors are now possible, and are expected to be used in the power field and other applications,” says Takashi Nakamura, Executive Vice President, Fukushima SiC Applied Engineering.
The most distinctive product using this technology is the switching module shown in the photo. This 6 inches square small module can switch a high voltage of 14KV with one piece. This is the world’s first SiC-based high-voltage DC switching module that can also operate in DC mode.
Going by the earlier practice, for power generation and transmission, mechanical switches are used which come with their challenges of shorter lifetime and difficulties in controlling them. Also, these mechanical devices use an inert gas to reduce arcing, which is also a greenhouse gas. The company aims to revolutionize the power system by introducing this switching module based on SiC semiconductors that can operate at such high voltage and high speed. This will also alleviate existing environmental and maintenance problems and potentially build a power network with digital control.
Their high power high voltage SiC semiconductor has found usage in one important sector - medical devices. Fukushima SiC Applied Engineering has developed a compact neutron source to reduce the size of the conventional Boron Neutron Capture Therapy (BNCT) systems. This power supply made it possible to install the BNCT device in the treatment room without the need for a separate electrical room or other grandiose equipment. “The compact neutron source is less than one meter in length and can create a uniform neutron field from the skin to a depth of 25 cm by arranging six compact neutron sources around the body,” explains Mr Nakamura. Current BNCT can treat tumours up to 5 cm deep from the skin.
Fukushima SiC Applied Engineering’s advanced SiC Semiconductors can also be applied in transportation equipment, transformerless power transmission and railroads. The company is also plannning manufacture of the low-cost SiC wafer, which will enable them to expand the applications of the SiC devices.