High Power Semiconductor Devices and Solid State Switches for Pulsed Discharge Applications

Abstract

Based on long term experience, collected mainly with military applications like Rail Guns and Active Armour, a range of optimized semiconductor devices for pulsed applications was developed by ABB Switzerland Ltd and described in this presentation. The presented devices are optimized for pulsed discharge and fit very well for switching the short but high electrical power demand used for magnetic forming. Devices are available in different versions with silicon wafer diameters up to 120 mm and blocking voltages of over 6500V. Because of the different application requirements a differentiation is made in device technology. Depending on the discharge circuit, devices for low, medium, or high di/dt can be selected and the difference in advantages and disadvantages between both technologies will be described. To minimize the inductance between switching device and freewheeling diode, ABB can integrate this diode monolithic on the switching wafer. These so called reverse conducting devices are very common for magnetic forming applications. Thyristor structures are commercially available up to 8500V with 120 mm silicon wafers and GTO-like structures are available up to 4500V with 91 mm silicon wafers. For higher voltages or higher currents a combination of devices in series and/or parallel connection is required. The presentation will also describe the evolution of complete discharge switching modules in the range of 10kV / 50 kJ, a large discharge system of 21kV / 200kA, and a newly designed high current switch in the range of 15kV / 3MJ. The solid state switch solutions offered today and those shown in the presentation are based on a standard platform of components existing already for several years. For reliability reasons it is of great importance that the switch assemblies for high current pulsed applications are designed in cooperation with the device manufacturer who has in-depth knowledge of the switching behavior of the semiconductor components under pulsed conditions. The advantage of a complete switch assembly is that the whole unit can be tested under application conditions. ABB has a test capability up to 65 kV and 85 kJ stored energy.