Active and Passive Reset Circuits for Multistage Magnetic Pulse Compression (MPC) Circuits Used in Gas Laser Applications

Magnetic pulse compression (MPC) circuits are commonly used in pulsed power circuits for powering gas lasers to shorten the duration of the pulse. If the core of every magnetic switch in the MPC is biased to
$-\Delta B_{r}$
by a reset circuit, then the voltage hold-off time is doubled, and the cross-sectional area required is halved. Reset circuits must be isolated from the high-voltage pulses appearing in the pulsed power circuit using filters. The required filter (inductor) size becomes too large if the reset circuit is connected directly in parallel to the magnetic switches, especially if the volt-sec product across the filter inductor is large. The most common, existing reset circuits available in the literature directly connect in parallel to the magnetic switch (
$s$
) and, therefore, require larger filter sizes to protect the reset circuitry. In addition, reset circuits cannot always be wound on the magnetic core to create a step-down transformation of the pulsed power voltages (lack of physical space or the use of a single primary winding). This article proposes a new reset circuit topology which resolves these problems by enabling the use of the smallest possible filter size (inductance value). In addition, only a single reset circuit is needed to reset multiple magnetic switches in the MPC network. An active reset circuit is also proposed which is more suitable for resetting magnetic cores that are relatively harder, i.e., requiring higher H values to saturate (equivalent currents greater than a few amperes). The reset circuits discussed in this article can in general be applied to many pulsed power applications employing MPC networks.