Silicon Carbide MOSFET-based Full-Bridge for Fusion Science Applications

Switching power amplifiers (SPAs) are typically built with insulated gate bipolar transistors (IGBTs) and have a wide variety of applications within the fusion science community, including feedback and control systems for dynamic plasma stabilization in tokamaks, inductive and arc plasma sources, radio frequency helicity and flux injection, RF plasma heating and current drive schemes, ion beam generation, and RF pre-ionizer systems. SiC MOSFETs offer many advantages over IGBTs including lower drive energy requirements, lower conduction and switching losses, and higher switching frequency capabilities. When comparing SiC and traditional silicon-based MOSFETs, SiC MOSFETs provide higher current carrying capability allowing for smaller package weights and sizes and lower operating temperature. Eagle Harbor Technologies (EHT) is proposing to design, construct, and test a SiC MOSFET-based full- bridge SPA. EHT will leverage the proprietary gate drive technology previously developed with the support of a DOE SBIR, which will enable fast, efficient switching in a compact form factor. EHT designed, built, and tested a SiC MOSFET-based SPA. The work began with SiC MOSFET device testing, which demonstrated the utility of the EHT proprietary gate drive for improving switching speed, quantified the energy lost per switching cycle, and characterized the maximum current per device. EHT produced a SiC MOSFET-based SPA printed circuit board, which was successfully tested into resistive, inductive, and resonant loads at high current and switching frequency. Working with the Helicity Injected Torus (HIT), EHT designed an upgrade to the HIT SPAs to be implemented in a Phase II program. In Year 1, EHT will design and build a second generation SiC MOSFET-based SPA using the lessons learned in the Phase I program. The SPA will be tested into resistive, inductive; plasma loads and demonstrates arbitrary pulse generation. In Year 2, EHT will completely replace the SPAs at HIT, which will more than double the switching frequency and increase the output current per SPA while lowering the parts cost per SPA. EHT will support the installation and testing at HIT while completing the documentation and commercialization effort. An off-the-shelf SPA that is straightforward to use and integrates into experimental systems will benefit the fusion science community, which primarily develops power systems in house, thereby utilizing time and resources that could be used on plasma physics and fusion science research. Similar devices are used in other research areas including linear particle accelerator supplies, high voltage ion implantation supplies, RF cyclotron power supplies, high power pulse width modulation amplifiers, and high power trigger systems. Additionally, the EHT SiC MOSFET-based SPA will allow for new capabilities for etch and sputtering applications within the materials science and semiconductor processing communities.