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The U.S. Naval Research Laboratory is developing a rep-rate charger for a 60-kJ capacitor module. The charger is lithium-ion battery powered and must charge up the capacitive load 50 times over a 5-min period with roughly 1 s between each charge cycle. This paper examines some aspects of the design: lithium-ion battery energy storage, hard switched dc–dc converter, high-voltage rectifier, and capacitive load with pulsed power switching. The lithium-ion batteries are arranged in 12, 16-cell, 50 V modules that are connected in series to form a roughly 600 V prime power supply. A hard switched dc–dc converter with full-bridge rectifier is used to charge the capacitor and a pulse forming network is used to discharge the capacitor into the load. This paper will discuss the system design and available test data. [ABSTRACT FROM PUBLISHER]

Three 26650 LiFePO 4 (LFP) cells are cycled using a 40 A pulsed charge/discharge profile to study their performance in high rate pulsed applications. This profile is used to simulate naval pulsed power loads planned for deployment aboard future vessels. The LFP cells studied experienced an exponential drop in their usable high-rate recharge capacity within sixty cycles due to a rapid rise in their internal resistance. Differential capacitance shows that the voltage window for charge storage is pushed outside of the recommended voltage cutoff limits. Investigation into the state of health of the electrodes shows minimal loss of active material from the cathode to side reactions. Post-mortem examination of the anodic surface films reveals a large increase in the concentration of reduced salt compounds indicating that the pulsed profile creates highly favorable conditions for LiPF 6 salt to break down into LiF. This film slows the ionic movement at the interface, affecting transfer kinetics, resulting in charge buildup in the bulk anode without successful energy storage. The results indicate that the use of these cells as a power supply for high pulsed power loads is hindered because of ionically resistant film development and not by an increasing rate of active material loss. [ABSTRACT FROM AUTHOR]

The future naval fleet will deploy many electrical loads aboard them, many of which will be pulsed power loads that operate in a transient manner and generate high electromagnetic fields. It remains unclear to what extent high magnetic fields will affect the corrosion rate of structural and high current conducting alloys. Considering the high-pulsed currents carried within many pulsed power systems, it is of increased interest to understand what impact their deployment will have on the metallic corrosion of their own conductors as well as the structural elements around them while operational in a maritime environment. In this paper, a unique test bed has been developed on which the impact that high-pulsed currents and their induced magnetic fields have on the rate of metallic corrosion can be studied. Pulsed currents, with amplitudes just shy of 10 kA and full-width half-max lengths of roughly 4 ms, are conducted through material samples of interest immersed in a salt solution. The results from four different metallic alloys will be presented, namely, 304 stainless steel (SS), 416 SS, 1018 steel, and 8620 steel. To measure the rate of corrosion, linear polarization measurements and scanning electron microscope (SEM) imaging are used. Baseline experiments, in which the samples are only exposed to 3.5% NaCl, have also been performed to isolate the impact of high-pulsed current on the rate of corrosion. While corrosion kinetics are presented, the intent of the research is to identify if and how pulsed magnetic fields will impact material degradation, so that pulsed power engineers can prepare for it in their future system designs. [ABSTRACT FROM AUTHOR]

There is considerable need for a mobile, reliable, efficient, and compact prime power supply for use in a host of directed energy applications. Recent improvements in the energy and power density of electrochemical lithium-ion batteries have made them a very viable option for these types of applications where fast and rep-rate operation is of interest. Despite the proven ability of lithium-ion batteries to source high currents, it is still unclear how they age when they are used to repeatedly source high-rate currents in a pulsed manner, as they must when used in a repetitive rate prime power supply. Similarly, it is unclear how elevated rate recharge affects the life of the battery. Research has been performed at University of Texas at Arlington in which high-power, 2.6 Ah lithium-ion batteries have been repeatedly discharged and recharged at high pulsed rates. This paper will discuss the potential of lithium-ion batteries for use in these applications and will present experimental results performed when two 2.6 Ah cells were both discharged at 28 A (10.8C) and recharged at 9 A (3.5C) to 2.5 and 2.0 V, respectively. [ABSTRACT FROM PUBLISHER]

Numerous research efforts have been undertaken to improve the feasibility of fielding compact pulsed power systems for a wide variety of applications. Each of these research efforts focuses on specific areas of pulsed power, but few papers have focused on the performance of a grid independent prime power source. This critical component is often overlooked in mobile pulsed power systems. Though not within the pulsed power community, a great deal of work has been performed by those in the electrochemical energy storage community to improve the energy density, power density, working voltage, and cycle life of electrochemical cells. This paper has helped to develop new energy storage technologies for applications such as consumer electronics, electric vehicles, and electrical grid energy storage. However, these electrochemical cells were not developed with pulsed power applications in mind. For that reason, a large amount of research is needed to understand how to effectively use electrochemical cells in pulsed power applications. In this paper, a number of different energy storage chemistries, including lithium-ion batteries, lead acid batteries, and bi-polar nickel metal hydride batteries, have been evaluated for use in pulsed power applications as a result of their high power and energy densities. [ABSTRACT FROM PUBLISHER]

The editors of this Special Issue of the IEEE Transactions on Plasma Science (TPS) are pleased to present an issue that documents a wide range of topics being actively studied within the field of Pulsed Power Science and Technology (PPST). Many of the articles contributed to this issue are from the participants of either the 20th IEEE Pulsed Power Conference (PPC 2015) or the 26th IEEE Symposium on Fusion Engineering, which were jointly held May 31 through June 4, 2015 in Austin, TX, USA (http://ece-events.unm.edu/ppcsofe2015/). Each respective conference has a long history of serving their community as gathering forums for the presentation and discussion of their field’s research topics. [ABSTRACT FROM AUTHOR]

The papers in this special issue were presented at the IEEE Pulsed Power and Plasma Science Conference (PPPS 2013) held June 16-21, 2013 in San Francisco, CA. This meeting was the combination of the 19th biannual IEEE Pulsed Power Conference and the 40th annual IEEE International Conference on Plasma Science. [ABSTRACT FROM PUBLISHER]

We are pleased to present this fourth special issue of the IEEE Transactions on Dielectrics and Electrical Insulation (TDEI) on Power Modulators and Repetitive Pulsed Power. A call for manuscripts for this volume was issued in TDEI and in conjunction with the 2012 IEEE International Power Modulator and High Voltage Conference (IPMHVC), which was held in San Diego, CA, USA during June 3-7, 2012. This meeting has emerged from a long tradition of jointly held International Power Modulator Symposia and High Voltage Workshops which eventually merged into a single conference for the first time in 2010 and again in 2012. The IPMHVC provides a forum for researchers and practitioners, who are engaged with the science and technology of power modulators and repetitive pulsed power as well as closely interrelated research on high voltage questions and developments, to meet and exchange ideas and the latest advances in these fields. There has been a strong and growing international interest in these topics, as is indicated by participants from 26 different countries and a steadily increasing number of abstract submissions, which exceeded 300 at this most recent IPMHVC. [ABSTRACT FROM AUTHOR]

In high-energy pulsed power applications, the metallic conductors are expected to heat up significantly due to resistive losses. In the pulsed case, materials exposed to short loading times, from 0.1 μs to 100ms behave different from those exposed to long loading times, 1 min to 1 h [1-4]. With this in mind, it is important to understand the mechanical properties of metals when they are heated rapidly so that the correct mechanical properties are considered when designing high-energy experiments where the thermal and mechanical stresses are high. An expanding ring experiment, similar to the one originally designed by Gourdin et al[5-7] has been set up at the Institute for Advanced Technology (IAT) to test such mechanical properties. In Gourdin's work the ring specimen under test sits radially around the center of a primary coil that is driven with a current pulse from a near critically damped RLC circuit. The ring expands and fragments due to the induced electromagnetic forces. In order to determine material properties at elevated temperatures, an inductive heating source has been developed to rapidly heat the ring specimen to temperatures as high as the melting temperature in 10?s of milliseconds, immediately prior to the application of electromagnetic expansion forces. The data generated will quantify the sensitivity of material properties to the rate and duration of heating in commonly used materials for development and validation of appropriate constitutive equations. [ABSTRACT FROM AUTHOR]