Marx generator

About: Marx generator is a research topic. Over the lifetime, 1276 publications have been published within this topic receiving 8970 citations.

Pulse generator with intermediate inductive storage as a lightning simulator

Abstract: Compact transportable generators are required for simulating a lightning current pulse for electrical apparatus testing. A bi-exponential current pulse has to be formed by such a generator (with a current rise time of about two orders of magnitude faster than the damping time). The objective of this study was to develop and investigate a compact pulse generator with intermediate inductive storage and a fuse opening switch as a simulator of lightning discharge. A Marx generator (six stages) with a capacitance of 1 μF and an output voltage of 240 kV was employed as primary storage. In each of the stages, two IK–50/3 (50 kV, 3 μF) capacitors are connected in parallel. The generator inductance is 2 μH. A test bed for the investigations was assembled with this generator. The generator operates without SF6 and without oil in atmospheric air, which is very important in practice. Straight copper wires with adjustable lengths and diameters were used for the electro-explosive opening switch. Tests were made with active-inductive loads (up to 0.1 Ω and up to 6.3 μH). The current rise time is lower than 1200 ns, and the damping time can be varied from 35 to 125 μs, following the definition of standard lightning current pulse in the IEC standard. Moreover, 1D MHD calculations of the fuse explosion were carried out self-consistently with the electric circuit equations, in order to calculate more accurately the load pulse parameters. The calculations agree fairly well with the tests. On the basis of the obtained results, the design of a transportable generator was developed for a lightning simulator with current of 50 kA and a pulse shape corresponding to the IEEE standard.

Development of a 0.6-MV Ultracompact Magnetic Core Pulsed Transformer for High-Power Applications

Abstract: The generation of high-power electromagnetic waves is one of the major applications in the field of high-intensity pulsed power. The conventional structure of a pulsed power generator contains a primary energy source and a load separated by a power-amplification system. The latter performs time compression of the slow input energy pulse and delivers a high-intensity power output to the load. Usually, either a Marx generator or a Tesla transformer is used as a power amplifier. In the present case, a system termed “module oscillant utilisant une nouvelle architecture” (MOUNA) uses an innovative and very compact resonant pulsed transformer to drive a dipole antenna. This paper describes the ultracompact multiprimary winding pulsed transformer developed in common by the Universite de Pau and Hi Pulse Company that can generate voltage pulses of up to 0.6 MV, with a rise time of less than 270 ns. The transformer design has four primary windings, with two secondary windings in parallel, and a Metglas 2605SA1 amorphous iron magnetic core with an innovative biconic geometry used to optimize the leakage inductance. The overall unit has a weight of 6 kg and a volume of only 3.4 L, and this paper presents in detail its design procedure, with each of the main characteristics being separately analyzed. In particular, simple but accurate analytical calculations of both the leakage inductance and the stray capacitance between the primary and secondary windings are presented and successfully compared with CST-based results. Phenomena such as the core losses and saturation induction are also analyzed. The resonant power-amplifier output characteristics are experimentally studied when attached to a compact capacitive load, coupled to a capacitive voltage probe developed jointly with Loughborough University. Finally, an LTspice-based model of the power amplifier is introduced and its predictions are compared with results obtained from a thorough experimental study.

Design considerations for a semiconductor-based Marx generator for a pulsed electron beam device

Abstract: The pulsed electron beam device GESA modifies the surface of a metallic material by means of melting and subsequent cooling both at high temperature gradients. Heating of a thin surface layer is performed by applying an electron beam. In existing GESA devices a rectangular voltage is used for accelerating the electrons. It is delivered by LC-networks in Marx configuration. For a new GESA device a semiconductor-based pulse generator is being developed. This novel design concept for a GESA device comprises a unipolar Marx configuration, which is designed for a rectangular voltage of 120 kV and a maximum current of 150 A at a pulse length of up to 50 µs. A fast rise of the voltage within less than 100 ns is required to foster an instantaneous plasma generation at the cathode. Hence, fast switching is required. The paper describes aspects of the design of the semiconductor-based pulse generator.

Modular, Ultra-compact Marx Generators for Repetitive High-power Microwave Systems

Abstract: The essential demand for high-power microwave (HPM) devices for both military and civil applications, such as convoy protection and car stopping, requires compact repetitive pulsed-power generators. We report on the latest developments in the technology of our balanced, coaxial Marxtype generators, which distinguish themselves by using a fundamental modular concept for reasons of scalability. The Marx generators especially make use of inductive charging technology to ensure high-repetitive operation. The Marx stages were completely redesigned. Marx generators with a variable number of stages were assembled and successfully tested up to charging voltages of 50 kV for up to 10 stages and up to 40 kV for the 20 stages. Burst mode operation for a duration of 10 s at a pulse repetition frequency of 100 Hz is reported. In order to gain an in-depth insight into the behavior of an inductive Marx generator during the charging and the discharging phases and to derive precise information for the design of future generators, we developed an advanced PSpice simulation model. The breakdown dynamics of the spark gaps was implemented by making use of the Vlastos formula; parasitic eects, such as stray capacitances, were taken into account.

Output performance of the coaxial‐type Marx generator consisting of BaTiO3 series ceramic capacitors

Abstract: We have theoretically analyzed the output performance of the coaxial‐type Marx generator consisting of BaTiO3 series ceramic capacitors. In this analysis, the capacitance of the BaTiO3 series ceramic capacitor has been considered to be variable with applied voltage. The results were compared with experimental results, and fairly good agreement was obtained. As a result of this analysis, it was clarified that the BaTiO3 series ceramic capacitor was not able to store efficiently the electrical energy when charged at high voltages. On the other hand, the SrTiO3 series ceramic capacitor has an almost constant capacitance against applied voltages, so that stored energy may be extracted efficiently. We have quantitatively revealed the superiority of SrTiO3 series ceramic capacitors over BaTiO3 series capacitors.