There is currently a need for fast, high voltage power electronic modules that are capable of switching at very short pulse widths to replace old-technology slower thyristors in pulse power systems. For lack of better suited switches in the market, high-voltage IGBT modules are currently being explored for such applications even though, as shown in this proposal, thyristor physics is much superior to IGBT physics for pulse power and using fast thyristors would be the sound technical approach. While state-of-the-art fast SGTO thyristors offering high di/dt capability and short recovery time have already been developed by our team and are adequate for applications that employ resonant switching at pulse widths down the 1 microsecond range, further effort is needed to push below microsecond, and many other important applications, such as the parallel-to-series capacitor switch arrays for Marx-based klystron modulators used in high-energy particle accelerators and colliders, employ hard switching with a largely resistive load; for these hard-switched applications the main problems, yet unresolved, are switch turn-off time and switching energy losses, which prevent operation in the microsecond and sub-microsecond range, as well as effective module protection against the ultra sharp electrical transients experienced. In Phase I of this project Silicon Power will efficiently perform a matrix of full physics-based simulations to guide the modification, by means of irradiation, of the carrier lifetime profile in its existing devices such as to improve their turn-off capability and we will test, at sub-microsecond pulse width, complete single-die module prototypes containing irradiated devices with a novel integrated switched-varistor- based protection. In Phase II larger multi-die modules, suitable for hard-switching 3.2kA peak currents and readily series-stackable to achieve 20kV, such as is required for use in particle accelerators, will be built, tested and delivered to DoE. Commercial Applications and Other
Benefits: The proposed pulse power switching modules are primarily developed to serve a particular pressing need in particle accelerator power systems engineering. However, military, industrial and commercial system designers have similar interest in the narrow pulse width, improved turn-off capability and high degree of module protection at high peak power ratings, and pulse power modules are also at the core of mainstream research on highly controllable, efficient and compact heavy-industrial and utility-level Smart Grid converters, such as the Intelligent Universal Transformers (DoE/EPRI) and Solid-State Power Substations (US Navy). Ultimately, the developments obtained under this program can deliver a module that, displaces over 50% of the 1.7kV-and-higher IGBTs now in use in motor drives and in utility and industrial switchgear, to very significant energy savings at the world scale.
