Review of opening switches for long-charge fieldable inductive storage systems

Opening switches (OS) applicable to fieldable inductive storage systems with long charge time of the inductor are reviewed. Main characteristics, required from the OS, are formulated. General requirements are reliable repetitive operation and compactness. For systems with a long charge time, e.g., for battery-based power supplies intended for driving electrothermal loads, typical parameters are fractions of a second conduction time, peak current of several tens of kA and the opening time less than 0.5 ms at a voltage of several kV. No off-the-shelf OS possessing such characteristics are available. Comparison of switches´ types and architectures was made. It brought to a conclusion that the hybrid technology is appropriate for long-charge inductive storage. Mechanical switches, e.g., vacuum and SF/sub 6/ circuit breakers, are suitable as the first stage, while a stack of semiconductor devices seems to be an optimal solution for the second stage of the OS. A novel approach allowing the enhancement of an order of magnitude of the turn-off-capability of fully-controlled semiconductor devices, such as GTOs and GCTs, is offered. Preliminary test results are presented.