A High Voltage Fast Switching Power Module for Active Control of Magnetic Fields and Edge Plasma Currents in Fusion Validation Platforms

Fast, reliable, real-time control of plasma is critical to the success of magnetic fusion science and is thought to be required for successful deployment of future power producing reactors. The development of efficient and robust solid-state switches for power systems for fast control of large inductance magnetic field coils, pulsed and/or modulated auxiliary radio frequency (RF) heating, neutral beam injection (NBI), and plasma injection systems is critically important. For example, the Lithium Tokamak Experiment (LTX) at Princeton University will use a high-power magnetron for localized electron heating. This tube requires short, high voltage conditioning pulses prior to the longer main pulse. Eagle Harbor Technologies (EHT) is proposing to design, construct, and test a high voltage (> 35 kV) switch that is compatible with both SiC MOSFETs and IGBTs. EHT will leverage the proprietary gate drive technology previously developed with the support of a DOE FES SBIR. This switch will be used as the basis of a demonstration power supply to drive the pulsed magnetron at LTX in a challenging environment. During the Phase I program, EHT developed two high voltage switch modules: one with isolated power gate drive and a second with inductively coupled gate drive. These switches were tested at 15 kV and up to 300 A at switching frequencies up to 500 kHz for 10 ms bursts. Robust switching was demonstrated for both IGBTs and SiC MOSFETs. In the Phase II program, EHT plans to continue the development of these HV switches based on the success of the Phase I program. EHT will develop a higher voltage switch (> 35 kV) that will be suitable for high pulsed and average power applications. EHT will work with LTX to utilize these switches to design, build, and test a pulsed magnetron driver that will be delivered to LTX before the completion of the program. This demonstration experiment will provide valuable application-based data of the high voltage switch power supply operating in a challenging environment of a fusion science experiment. The commercialization of a robust, high power, high voltage switch module would eliminate the challenges and complexity of other researchers developing a solid-state high voltage switch, while allowing users to take advantage of the latest efficiency developments in solid-state switching technology. Beyond fusion science, applications include fast HV pulses for high power RF production, fast capacitor charging systems, atmospheric plasma production and magnetic and strip-line kickers for linear accelerators. Broader markets include large particle accelerators, medical devices including particle accelerators for cancer therapies, semiconductor manufacturing, and defense applications. EHT has been working with several customers in each of these areas and continued development of the HV switch technology under this DOE SBIR program will greatly increase our ability to produce products that will support these applications.