Core reset considerations of the stepped impedance magnetic compression modulator

Core reset in a magnetic compression circuit for high repetition rate pulsed power applications remains an important issue. Here we present a stepped impedance transmission line pulse generator circuit and show that balanced recharging current of a discharged stepped impedance lumped element transmission line with saturable inductor switches in each cell can be used for lossless core reset. The unequal stage capacitances and the need for keeping the final charge voltages of each stage equal are accounted for. The use of pre-charge voltage and proper capacitance sequence in such stepped impedance magnetic compression line provides voltage multiplication in addition to pulse compression without the use of transformers. A single compression stage can generate a compressed pulse with amplitude 3 times the charging voltage. It is shown that the reset approach described herein can reset the system in microseconds without loss, even when driving a mismatched load, indicating this approach is suitable for operation above 10 kHz for long durations. This reset method will be implemented in a high voltage MPC stepped impedance line at USC to produce 90 kV pulses for research into high pressure streamer propagation physics. Higher voltage implementations are also being studied.