A RESONANT SERIES COUNTERPULSE TECHNIQUE FOR HIGH-CURRENT OPENING SWITCHES

A counterpulse technique for the controlled interruption of very high currents in inductive storage pulsed power systems is described and an alysed, and some simulation results of its performance are presented. The accompanying circuit comprises a pre-charged capacitor bank, conne cted in series with the inductive load, which has to be provided with a current pulse. Upon actuation, a resonant counterpulse current is cr eated in the opening switch, connected in parallel with the current so urce and the load. In this way, the opening switch is opened at low cu rrent. A separate closing switch prevents closing of the opening switc h at high voltage. Operation of the opening switch, often a mechanical switch, at low current and low voltage prevents are erosion of the co ntacts. The advantage of this circuit compared to other counterpulse c ircuits is that the capacitor bank does not experience a voltage rever sal. Electrolytic capacitors, which have a high energy density, are ap plied. The remaining energy of the capacitor bank after opening the op ening switch, is transferred to the load. The required initial voltage of the capacitor bank is only a few hundred volts, whereas it may be above a kilovolt in other circuits. Another advantage of the method de scribed here is that the load does not experience a pre-current, causi ng unwanted preheating of the load, before the resonant current is act ivated. At the moment, work is being performed at the Pulse Physics La boratory to develop the resonant series counterpulse circuit for use w ith rail accelerators, which must be supplied with current pulses in t he millisecond range up to the mega-ampere level.