Novel Switching Devices for Accelerator Modulators

This project addresses very high power switches for accelerators used in high-energy physics research and particle research. Existing devices have relatively slow switching times, compared to those required for the application. The proposed program seeks to develop high-voltage, high-current devices with much faster switching times and reduced conduction losses, thereby reducing heat and improving reliability. Two approaches are utilized here. The first is to develop switches operating at very low (cryogenic) temperatures, and the second is to apply proprietary switching topologies to this application. In Phase I, a cryogenic drive system was developed, and two cryogenic power modules were demonstrated in a liquid nitrogen bath switching 6000-volt, 240 ampere (megawatt-level) pulses. MTECH measured significant reductions in the switching times and on-state voltage of these devices. Phase II has been extended through June 14, 2014. In this work, several improved half-bridge (as opposed to single-switch) prototypes have been developed, and these are currently under test. These prototypes are expandable to handle megawatt power levels at continuous operation. MTECH believes these are the highest voltage levels achieved at cryogenic temperatures, and that this work represents a significant milestone. In the proposed Phase IIB program, MTECH will gather input from potential customers and end users in making the Phase II prototypes ready for commercialization by developing packaging, instrumentation, and interfaces that are useful in various applications and fields of work. Commercial Applications and Other Benefits: Apart from accelerator applications, which could lead to major breakthroughs in the understanding of fundamental physical phenomena, the high-power switches developed in this program could find use in power distribution systems for existing or future power grids Examples include superconducting magnetic energy storage (SMES) systems and turboelectric aircraft propulsion systems (in which MTECH currently has active programs), as well as superconducting power transmission, superconducting wind turbines, and medical and military applications.