대전류 펄스 성형이 가능한 150MW급 펄스파워 시스템의 설계 및 동작특성

A 4.8-MJ capacitive pulsed-power system (PPS) was designed and fabricated for electromagnetic launcher (EML) experiment. The PPS consists of eight 600-kJ segments, which can be operated independently. In each segment, six 100-kJ capacitor bank modules, a charging power supply, a dump and charge panel, and control circuit were integrated. The capacitor bank modules in the segment are charged at the same voltage up to 10 kV, but the trigger time of each module can be set up differently. The overall PPS system is controlled by a control program, which sets charging voltage and trigger time of each module and monitors the states of system component. All the control signals are transmitted through fiber optic communication. The 48 unit modules are connected in parallel to EML with high-voltage coaxial cables. A current amplitude of more than 1 MA and a pulsewidth of several milliseconds were achieved by the PPS. The PPS has been applied to several tens of firing experiments of EML successfully. The design, fabrication, and the test results of the 4.8-MJ PPS were described in this paper.

A capacitor-based pulsed power system of 4 MJ was designed and developed to propel projectiles of mass above 100 g to hypervelocites. The system used the modular approach, by integrating ten 400-kJ capacitor bank modules. A number of simulation studies were carried out viz., performance analysis of the system using Microcap simulation package, design of various pulsed power subsystems using ANSYS Maxwell simulation tool, and finite element transient analysis for current diffusion through the in-house developed software. Power transfer lines, coaxial cables, and pulse-shaping inductor were designed and fabricated. Various electromagnetic (EM) launchers were designed, developed, and fabricated. Modules are arranged on various racks and are integrated with the EM launcher. Launchers are initially test fired with four modules and then with ten modules. The data acquisition system was developed to measure module currents, in-bore position, velocity, and acceleration of armature. The pulsed power system was experimented up to 1.1-MA current pulse and was successfully test fired to accelerated 120-g mass projectile at a muzzle velocity of 2024 m/s.

Summary form only given. In many high current pulsed power systems much, if not all, of the energy is inductive or magnetic rather than electric and the electric fields are dominantly inductive rather than electrostatic. That is, in the usual expression for generalized electric field, E=-grad(V)-dA /dt, V is the scalar potential that gives rise to the electrostatic field, and A is the magnetic vector potential, from which the inductive field is derived. In problems where there are regions without voltage sources or charge separation, the electrostatic component does not exist, and the usual technique of solving the scalar Laplace's equation for the potential is inappropriate for determining the electric fields. Calculation of the magnetic vector potential is plagued by choice of gauge condition and specification of correct boundary conditions. Especially for coaxial (axisymmetric) systems typical of many pulsed power components and systems, where the current flow is in the (r,z) plane, there are two components of the vector potential that must be solved-each with its own boundary conditions. Specification of all the correct boundary conditions is non-trivial. In this paper, we present a convenient technique for the calculation of inductive electric fields in coaxial systems. The technique is based on the introduction of a vector electric potential that is derived from Poisson's equation, in combination with Faraday's Law and the E-D constitutive relation. In coaxial geometry, the electric vector potential is only azimuthal and, therefore, quasi-scalar. It is conveniently calculated with any two-dimensional Poisson equation solver, and the resultant inductive field distribution easily derived. We have used the technique in several pulsed power system designs with success. Specific examples of the application of the technique are given.

A 500 kJ compact pulsed power supply (PPS) system used for electromagnetic railgun (EMG) system has been developed to investigate the influence of electric parameters on muzzle velocity in the paper, from which the stability and reliability of the PPS system can be evaluated. The pulsed power supply system consists of ten modules, and each module is composed of a high energy density capacitor, a triggered vacuum switch, a pulse shaping inductor, a dump resistor and a crowbar. Influence of different parameters on the velocity was analyzed by ATP simulations in this paper. The parameters include capacitance, equivalent series resistance (ESR) of the capacitor, inductance, natural electric parameter and jitter time of the TVS. The ESR and natural electric parameters are critical influencing factors by comparing the simulation and experimental results. In the end, muzzle velocity deduced by the current, which is obtained from a new model of actual circuit, is about twenty percent lower than that in ideal condition. It is pointed out that the velocity error is mostly caused by ESR and natural electric parameter.

Pulsed power supplies (PPS) deliver high currents in a short period of time. Designing a pulse shaping inductor (PSI) requires major effort because of the electromagnetic forces exerted on the windings due to high pulse currents. A pulse shaping foil inductor is simulated with the help of finite element software COMSOL Multiphysics. Two different mechanical structures are designed in order to increase the strength of the inductor. The PSIs are manufactured and tested as a component of a 200 kJ PPS module. Test results show that the final PSI prototype can operate without any significant damage when the PSI current reach to 160 kA. Improvement process still continues to make the PSI more enduring.

Electromagnetic launching system is composed of the Electromagnetic Railgun (EMRG) and the large-scale Pulse Power System (PPS). According to the different test requirements of PPS and EMRG, the special master-slave distributed data acquisition software for electromagnetic launching system is designed by using LabVIEW graphic language. The test host and the sub-machines are multi-channel transient data acquisition systems based on PXI bus. The host PXI is used to measure the comprehensive parameters of the EMRG in multi-physical field. All sub-PXIs are used to diagnose the discharge current signals of each Pulse Forming Unit (PFU). The database management software uses C# programming language to design a friendly human-computer interaction interface, and uses SQL Server software to establish and manage the database, which realizes the comprehensive management of experimental data, tasks and resources involved in the EMRG experiments. The experimental information and experimental data are classified and filed, and the experimental data can be queried, and the experimental results can be analyzed and compared. The data acquisition and experimental database management software has perfect functions, friendly user interface, convenient operation, good versatility, and can also be used in other experimental occasions.

The armature trigger position of multi-stage electromagnetic coil gun has great influence on the exit velocity of projectile. The energy conversion efficiency of the coil gun can be improved effectively if the armature is triggered in the optimum position. So it is important to detect the projectile position in time. Several typical electrical and optical methods for position detection are summarized in this paper. The advantages and disadvantages of each method are analyzed and evaluated. And a new laser scattering measurement method is proposed. Results show that optical detection method is simple and easy to implement, but it is susceptible to environmental impacts.

This review paper reports various concepts of the gun propulsion system to meet the goal of the futuristic hypervelocity projectiles. The nonconventional concepts, such as liquid gun propellant, rail gun, coil gun, electrothermal gun, electrothermal chemical gun along with conventional energetic solid gun propellant have been discussed. Even though muzzle velocity around 2000 m/s has been claimed to be achieved using such nonconventional propulsion systems, it will take quite some time before such systems are in regular use in the battlefield. Hence, solid gun propellants containing novel energetic ingredients (binders, plasticisers, and oxidisers) would continue to be used in the near future and are expected to meet the requirements of the futuristic gun ammunition.

A 500 kJ compact pulsed power supply (PPS) system used for electromagnetic railgun (EMG) system has been developed to investigate the influence of electric parameters on muzzle velocity in the paper, from which the stability and reliability of the PPS system can be evaluated. The pulsed power supply system consists of ten modules, and each module is composed of a high energy density capacitor, a triggered vacuum switch, a pulse shaping inductor, a dump resistor and a crowbar. Influence of different parameters on the velocity was analyzed by ATP simulations in this paper. The parameters include capacitance, equivalent series resistance (ESR) of the capacitor, inductance, natural electric parameter and jitter time of the TVS. The ESR and natural electric parameters are critical influencing factors by comparing the simulation and experimental results. In the end, muzzle velocity deduced by the current, which is obtained from a new model of actual circuit, is about twenty percent lower than that in ideal condition. It is pointed out that the velocity error is mostly caused by ESR and natural electric parameter.

Understanding, modeling and simulating the behavior of thermally and electrically conductive materials under simultaneous high electric current pulse and mechanical preload conditions has long been a topic of interest for various applications involving electromechanical systems. To this end, the present work describes a computational framework that enables the fully coupled electromagnetic and thermoelastic analysis of such systems. The partial differential equations (PDEs) representing the electrodynamic and thermodynamic conservation laws are utilized and encapsulated in a computational environment enabling their numerical solution. A specific contribution of the framework is that it is capable of solving the non-linear forms of the relevant PDEs that are formed due to the dependence of the material properties on state variables such as temperature. The proposed framework is applied for a specific high-current testing apparatus under construction in our laboratory. A high current pulse is conducted through a mechanically pretensioned specimen and generates Joule heating activating thermo-elastic strains in conjunction with Lorentz body forces influencing the associated dynamic thermo-structural response of specimens of interest. Application of the developed framework enables the generation of field predictions for the quantities of interest. Selective simulation results are presented to demonstrate the capabilities of the proposed framework followed by discussion and conclusions.

Pulse alternator-based pulse power systems for electromagnetic rail guns store the required energy for powering the rail gun as stored mechanical inertial energy in the rotating member. The pulse alternator (PA) converts the stored inertial energy into electrical energy that is supplied to the rail gun terminals. The losses in the system and energy delivered to the rail gun projectile reduce the stored inertial energy of the pulse alternator by reducing the operating speed. Pulse alternators require a charging mechanism to accelerate the rotor of the alternator to the desired speed, providing the mechanical stored energy. This is generally accomplished by a motor attached to the alternator shaft. This paper describes the design, manufacture and initial testing of a high speed, water- cooled permanent-magnet (PM) synchronous motor specially designed to accelerate a high speed pulse alternator. The charging motor has been designed to accelerate the pulse alternator from zero speed to full rated alternator speed and to accelerate the alternator back to rated speed after the pulse discharge. Two PM motors are also used to synchronize two separate paralleled pulse alternators prior to discharge into a rail gun load. The PM motor is directly attached to the PA shaft and designed to minimize the axial footprint of the assembly. The motor is operated in a continuous duty cycle which requires water cooling of the stator assembly and air cooling of the rotor. The PM synchronous motor is powered by a variable-frequency, variable voltage electronic drive and operated in a constant torque mode.

It has been recognized from the earliest days of electric gun research, that pulsed power is critical for its successful development. Electric launcher concepts investigated over the last two decades include electromagnetic (EM) railguns and coil guns, and electrothermal and electrothermal-chemical launchers. Here, pulsed power supply considerations for EM launcher applications are examined by the author.

A magnetically insulated ion beam diode with a gas-break down plasma anode/sup 1/ is being developed as a possible high repetition rate intense ion beam source./sup 2,3/ This paper discusses the design and operation of the five independent pulsed power systems required to produce /spl les/ 200 kV, 40 kA, 100 ns power pulses at up to 1kHz (burst mode) repetition rates. The first part of this paper will briefly describe the diode, followed by an overview of the pulsed power systems. The bulk of the paper will then describe these systems in detail, concentrating on the use of electrolytic capacitors in high current repetitive pulse storage banks, the use of SCR series stacks for high voltage switching, and the design and operation of two solid state pulsers.

High energy density high-voltage metallized film capacitor is one of the most suitable energy storage elements in pulsed power system, such as Electromagnetic Gun (EMG) system. But the voltage drop at high voltage is an inherent problem of metallized film capacitor, which will affect the launching precision of EMG system. To improve the launching precision, this paper mainly focuses on the voltage maintaining method of capacitor charging power supply (CCPS). Based on the traditional series resonant CCPS, a voltage maintaining method is proposed, which feeds energy to capacitor to compensate voltage drop during launching delay. The scheme is simple and easy to implement. It also can switch smoothly from fast charging stage to micro power charging maintaining stage. Furthermore, for the portable CCPS fed by lithium ion battery, the charging voltage maintaining precision is deteriorated by the common-mode voltage. So a common-mode voltage restraining circuit is proposed and analyzed in detail. A 4kV 1.0kJ/s CCPS prototype was constructed. The experimental results of the prototype show that, the CCPS has approximate maintaining accuracy of 0.1%.

: A 4.5-MJ capacitor-based pulsed power system (PPS), previously owned and operated by General Dynamics Land Systems in the early 1990s, was acquired by the U.S. Army Research Laboratory. The system was placed in storage in the late 1990s. It was recently modified and, in 2001, was placed back in operation at barricade C to operate with an electromagnetic (EM) railgun load. On 9 February 2006, a capacitor in module 4 developed an internal short while charged to 7.2 kV. Further inspection revealed arc damage at the center post terminal on 20 capacitors in nearby modules and some amount of rust on every capacitor case. After the incident, all modules were charged individually to 3.2 kV and discharged into a short. The data indicates that the damaged center posts likely occurred quite some time ago. New hardware was required to restore relevant capability to barricade C. The capacitors from the primary and essential basis for the system. The PPS must be capable of reliably delivering higher energy pulses. New capacitors using modem manufacturing techniques and improved dielectrics were purchased. New center posts were designed and replaced concomitant with the installation of new capacitors. Lastly, the bus work that connects the pulse-forming inductor to the pulse-forming-network output cable was replaced in order to decrease the number of bolted joints and increase reliability at high-energy operation. Upon completing the upgrade in hardware, each module was discharged into a short at the breech of the railgun at initial charge voltages of 3, 5, and 7 kV. Additionally, all 18 modules were sequentially discharged into the shorted breech. Lastly, firings using a railgun were completed without incident. All simulation models were updated as necessary throughout the commissioning process. The stored energy at the maximum charge voltage of II kV is now 5.2 MJ.