Novel hybrid XRAM current multiplier

Abstract

The conventional XRAM (MARX spelled backwards) current multiplier circuit is similar in concept to the better known MARX voltage multiplier circuit. In the MARX circuit, capacitors charged in parallel from a voltage source are switched to discharge in series producing an output voltage approximately equal to the sum of individual capacitor voltages. In the XRAM circuit, inductors energized in series from a current source (battery, homopolar generator, other) are switched to discharge in parallel, producing an output current which is the sum of the individual inductor currents. In high energy pulsed power systems these multiplier techniques simplitj primary power design at the expense of more complex switching. circuit described in this paper minimizes switching requirements while retaining the positive benefits of the conventional XRAM circuit. It also provides a smooth rising current waveform which is useful for EM and ET gun research. The tradeoff for these benefits is that, during switching, approximately 50% of total system energy is stored in a capacitor bank of simple design.In addition to simplified switching, the hybrid concept offers other advantages over either an all capacitive or all inductive system. As a laboratory power supply at 2-3 MA current and 10-20 MJ stored energy, it doubles energy which would by, available from a capacitive system while offering the current stifhas" available from an inductive system. Less obvious but potentially of greater interest, the concept appears to scale to high energy (10's to 100's of MJ) for either a distributed energy or multi shot power supply. This paper outlines two XRAM circuit concepts, and discusses the distributed energy and multi-shot aspects of the hybrid concept. It also describes a more detailed study of a battery powered hybrid XRAM current doubler design being considered for use as a general purpose laboratory inductive energy supply, operating at up to 2.5 MA with as much as 10 MJ of electrical energy stored. The circuit described is modeled using known values from existing circuit components. Resulting waveforms are shown and benefits derived from the use of this circuit are compared to those from a conventional XRAM current doubler as well as from a direct, inductive store, system design. The hybrid I. ~NTRODUCITONAs EML research moves to higher energy and higher rojectile velocity systems, stored energy per shot is typicalfy 5 -10 UT and desired peak current is at least 1 -2 MA.In experiments where multi-shot firing capability is desired, the stored energy requirements are often increased in proportion to the number of shots desired in a burst. One system presently being designed [ 11 will store more than 500 UT and w i l l deliver peak current of up to 5 MA. Present technology utilizes either capacitive energy storage with closing switches or inductive storage with opening switches to meet these needs. Both types of systems become very Thin work was supported in part by Wright Laboratory and SDIO under Contract No. FO8635-914-OOO1.expensive an...

Comparisons of three inductive pulse power supplies

“…During ICCOS, Th 1-9 are on or shorted by the diodes inversely in parallel. So they just bear low voltages while ensuring the reliable cutting off for Th [1][2][3][4][5][6][7][8] . In this step, the load current attains the maximum 33.61 kA.…”

“…One is called the Slow Transfer of Energy Through Capacitive Hybrid meat grinder (STRETCH meat grinder) [1,2], which is presented by Institute of Advanced Technology (IAT). Another is XRAM modified by Institute of Saint Louis from the original XRAM [3].…”

Overview of circuit topologies for inductive pulsed power supplies

“…The XRAM was proposed by Werner Koch from Marx High Voltage Institute at Brunswick Technical University in 1967 [14]- [15]. Also, the CMIS (Cuttent Multiplier by Inductive Storage) developed by the Japan Steel Works Ltd. is a XRAM in essence [16].…”

Analysis and optimization of batteries powering inductive pulsed power supplies

“…Due to its advantage of energy density, inductive pulse power supply (IPPS) has become a promising type of power supplies for the electromagnetic launcher (EML) [1,2]. According to electrical circuit topology, IPPS can be divided into two categories: one is the XRAM class circuit, which was first proposed by Werner Koch et al in 1967 [3], utilising the series charging and parallel discharging of inductors to achieve current multiplication; the other is the Meat Grinder class circuit, first proposed by Oved Zucker et al in 1980 [4], and its current multiplication principle is magnetic flux compression.…”