Capacitive Pulsed Power Supply Research Articles

A Capacitive Pulsed Power Supply Circuit With ICCOS Technique for Reluctance Coil Launchers

A Capacitive Pulsed Power Supply Circuit With ICCOS Technique for Reluctance Coil Launchers

Improvement of high-power thyristor trigger circuit with switching-mode power supply for differential-mode noise reduction

This paper focuses on the differential-mode (DM) noise of high-power thyristor (HPT) trigger circuit with switching-mode power supply (SMPS) in capacitive pulsed power supply (CPPS). Parasitic parameter models of components are discussed and analyzed. Based on the parasitic parameter models of components, a DM noise prediction model of HPT trigger circuit with SMPS is developed. The generation mechanism and propagation paths of the DM noise in HPT trigger circuit with SMPS are investigated. To reduce the DM noise, a capacitive SMPS technique is adopted in the HPT trigger circuit with SMPS. Simulation results validate the theoretical analysis.

A Novel Surge Suppression Scheme for Capacitive Pulsed Power Supply

In capacitive pulsed power supply (CPPS), semiconductors, such as crowbar diodes, can be damaged by surge energy in worst cases, which reduces the reliability of CPPS. The generation mechanism of surge energy is discussed initially. A surgesuppression scheme is presented to reduce the breakdown risks of semiconductors. Surge voltages and currents are simulated and analyzed based on the classical circuit models of CPPS and railgun. Then, two installation positions of the surgesuppression device are systematically investigated. The simulated results show that installing the surge suppression device at the railgun muzzle can suppress the surge voltages induced by an armature leaving the railgun barrel, and installing the surge suppression device at the railgun breech can reduce overcurrents of semiconductors in reverse recovery phases. Ultimately, experimental results validate the theoretical analysis.

Differential-Mode Noise Prediction and Cancellation for High-Power Thyristor Trigger Circuit

This article is to predict and cancel differential-mode (DM) noise for high-power thyristor (HPT) trigger circuits and improve the reliability of capacitive pulsed power supply (CPPS). A lumped model of HPT trigger circuit is developed for the DM noise prediction within a concerning frequency range. The generation mechanism and propagation path of the DM noise are systematically studied. To attenuate the DM noise, a DM filter is proposed and discussed. The component parameters of the filter are investigated to improve its DM noise suppression effect. The DM spectrum for the HPT trigger circuit and the insertion losses of the DM filter are simulated and analyzed. Ultimately, DM spectrum tests are carried out. Both the simulated and measured results validate the theoretical analysis.

Utilization Optimization of Capacitive Pulsed Power Supply in Railgun

The excitation pulse current used to drive the railgun needs to present very a high magnitude (hundreds of kA) flat-top with very low ripple. At present, the main method to obtain this current is to increase the number of the capacitive pulsed power supply (PPS) modules. However, low utilization and massive volume of the railgun system would occur with this method, hampering the application of railgun. Therefore, the utilization optimization technology of PPS is researched in this paper. In order to obtain highly stable flat-top current, the control strategy of the capacitive PPS is designed, and a new charging voltage configuration is proposed, which significantly decreases the use of the capacitive modules. Besides, a miniaturization transformation scheme of capacitive PPS is proposed based on the control strategy. The result shows that the flat-top current ripple has the biggest influence on the PPS utilization, and the smaller the flat-top current ripple, the lower the utilization. When the current with 200 kA magnitude and 0.75% flat-top current ripple is achieved, an 81.9% decrease of volume and a 428.7% utilization improvement are achieved through miniaturization transformation.

An 18.3 MJ charging and discharging pulsed power supply system for the Space Plasma Environment Research Facility (SPERF): The subsystem for the magnetopause shape control coils.

The Space Plasma Environment Research Facility currently under construction at the Harbin Institute of Technology in China uses four magnetosheath coils (flux cores) and a dipole coil to generate the magnetic field required for the study on the magnetopause magnetic reconnection. Two groups of magnetopause shape control coils (labeled CK coils) are used to slightly adjust the magnetic field distribution on the magnetopause. A capacitive pulsed power supply (PPS) system with a modular design is developed to excite CK coils. The PPS system consists of six sets of PPS with the same principle and structure, which are used to excite six sub-coils of the CK coils, respectively. Each set of PPS consists of ten modules and one local controller, and each module consists of a charger and discharge unit. Each set of PPS can provide a pulsed current of no less than 400 kA for the corresponding sub-coil at 0.11ms when the charging voltage is 20 kV, and the duration of the pulsed current from the peak to 10% of the peak is no more than 0.6ms. The detailed design of the PPS is discussed in this paper, and the discharge test of the PPS is carried out to verify the design of the PPS. Because there are acquisition and control devices in the discharge unit, the electromagnetic interference immunity design is also discussed to ensure the normal operation of the PPS.

Modelling and simulation on a novel meat grinder circuit for the dynamic pulsed power load

Compared with the capacitive pulsed power supply (CPPS), the inductive pulsed power supply (IPPS) is considered to have broader prospects because of its theoretically higher energy densities. Most recent researches focus on characteristics of the IPPS with a fixed load, which is rather different from practical applications from the engineering point of view. In this paper, with the purpose of preliminarily verifying the IPPS’s feasibility, the performance of the novel meat grinder circuit with a dynamic load model is presented and analysed under PSpice environment. The analysis model is based on the parameters of the four-module IPPS and the pulsed power load built in Institute of Electrical Engineering. Finally, the comparison between the IPPS and the CPPS with same initial energy is carried out.

Design and characteristics of a modular integrated power supply for the system of flashlamp-pumped in inertial confinement fusion

• A 1.46 MJ capacitive pulsed power supply is designed by using the pulse thyristors. • The synchronous triggering of multiple sets of thyristors enables high current output of the pulsed power supply. • The high gate trigger system is developed to control the synchronous conduction of the thyristors of each module. • Simulation and project experience show that the high-probability failure will not affect the other components in the power supply. In order to study the adaptation of the semiconductors for the special power supply application, a capacitive pulsed power supply is designed by using the pulse thyristors. The modular integrated method is adopted to redesign the main circuit of the power supply. The synchronous triggering of multiple sets of thyristors enables high current output of the pulsed power supply, which can avoid excessive current passing through the thyristors and eliminate current-sharing measures of the thyristors. Applying the fast switching MOSFET and magnetic induction of pulse transformer, a set of high gate trigger system is developed to control the synchronous conduction of the thyristors of each module. The simulation and experimental results show that most of the faults occurring during the operation of the pulsed power supply can be limited by protection devices. Practical operation indicates that the pulse power supply can provide specific required pulse current and energy for the pulsed xenon lamp. The design method of the pulsed power supply can provide a reference for the design of the pulsed power supply, and lay a foundation for the higher capacitive energy storage application.

Discussion on Topologies of Quick Response IPPS Suitable for Closed-Loop Control of EML

High energy density makes inductive pulsed power supply (IPPS), a research focus of supplies for electromagnetic launch (EML). However, in existing IPPS topologies, the charging and discharging stages of the inductors cannot be separated, so the response time of IPPS can be as long as ten or even tens of milliseconds. For this reason, the real-time closed-loop control of the output current and muzzle velocity based on IPPS is nearly impossible, which might be one of its biggest drawbacks compared to the capacitive pulsed power supply (CPPS). In this article, a novel current maintainable meat grinder (CMMG) circuit capable of fast response for EML applications is proposed, in which the antiparallel diode can provide a current maintaining path. After the inductor completes its charging process, the current can be maintained for a period of time. Thus, the circuit can be in a hot standby state and can be triggered with a very short delay. Subsequently, two commutation methods for the CMMG circuit are explored. The first one is to introduce the inverse current commutation with semiconductor device (ICCOS) branch. In its experiment with an inductance energy of 22 kJ, the circuit maintains 77% of the charging energy in the first 10 ms and is triggered successfully after 28 ms with almost zero response delay. The second method is the superconducting switching technology, based on which the CMMG with self-shutdown circuit is proposed and simulated.

Analysis on the Influence of Breech Voltage on the Pulsed Discharge Characteristics of Capacitive Pulsed Power Supply in EML

Corresponding to the different gradient of the ideal working current, the movement process of the armature in the railgun bore can be divided into rising phase, stable phase and decreasing phase. Based on the load characteristic and the lumped-element equivalent circuit of the railgun, the characteristics of the railgun’s breech voltage in above three phases were analysed. Under the condition that the size of the launching system is close to the same, the change ranges of the breech voltage of the augmented railgun is much larger than that of the simple railgun, and the breech voltage of the augmented railgun is a very high forward voltage in the rising phase. The influence of the breech voltage on the discharge characteristics of the capacitive pulsed power supply was studied. In the rising phase, the high breech voltage of the augmented railgun has a significant adverse effect on the pulsed discharge characteristics of the capacitive pulsed power supply whose pulsed forming net consists of a large number of pulsed forming units with small energy storage and high resonance frequency. As a result, part of the stored energy of the capacitive pulsed power supply cannot be used effectively, which leads to the decrease of the working efficiency of the launching system. Using the launching system with a 13-MJ capacitive pulsed power supply and a medium calibre augmented railgun, the launching simulation and test were completed, and the analysis was verified. The research has important enlightenment for improving the match between the capacitive pulsed power supply and the railgun.

Inductive Pulsed Power Supply for a Railgun Artillery System

The power supply for a railgun used as long-range artillery is investigated in this paper. As described in an earlier study, an 8-kg projectile is accelerated to 2500 m/s in order to bring it on a steep ballistic trajectory. To further investigate the electrical behavior of the proposed 25-MJ muzzle energy railgun, simulations with two different power supply chains, each starting with batteries, were performed. The more conventional approach uses a capacitive pulsed power supply (CPPS), the other investigated option is an inductive pulsed power supply (IPPS). An IPPS was designed in detail and set in comparison with a design of a CPPS. Parameters such as size, weight, efficiency, maximum rep-rate, and maximum shots per burst are estimated. Results show that a simple battery–inductor approach promises to be more compact but CPPS would be more energy efficient. Results give valuable support with respect to several design decisions.

Research on self-consistent control strategy of multistage synchronous induction coil launcher

Trigger control strategy is of vital importance for the multistage synchronous induction coilgun (MSSICG). According to the operating principle of MSSICG, we can theoretically obtain a sustained and steady acceleration which is sufficient to push the projectile to high speed by means of continuously increasing the series of driving coils and matching with the appropriate trigger strategy. However, the transition time between the adjacent coils decreases with the increase of the projectile velocity, which leads to the weakness of the traditional position or time trigger control. In this paper, a self-consistent control strategy of MSSICG was proposed. Its accuracy and flexibility are verified through an illustrative example of a 25 stages synchronous coilgun. The results coincide well with that by finite-element method (FEM), and the error of muzzle velocity is only 3.4%. Based on this method, the influence of slip speed and rise length on the adaptive control effect is calculated and analyzed, and accordingly proposed to use variable slip speed. As far as the capacitive pulsed power supply (CPPS)-based MSSICG is concerned, the research methods and results in this paper have both theoretical and pragmatic value in simplifying the design process and improving energy conversion efficiency (ECE).

Overview of circuit topologies for inductive pulsed power supplies

The pulsed power supply (PPS) is one important component in the electromagnetic launch system. The inductive PPSs have attracted researchers’ attentions with the major advantages of high energy storage density (over the capacitive PPSs) as well as simple structure and easy control (over the rotating mechanical PPSs). As for the inductive PPSs, the circuit topology of the basic module will directly determine the comprehensive performance of the whole system. From the perspectives of working principles, strengths, weaknesses, and comprehensive performance, this paper presents a historical and technical review of the major circuit topologies for the inductive PPSs.

Performance Analysis and Parameter Optimization of CPPS-Based Electromagnetic Railgun System

A fast solving method for the launching process of the electromagnetic railgun and an automatic assignment method for the trigger strategy of the capacitive pulsed power supply (CPPS) are proposed. The accuracy of the solving method and the feasibility of the assignment method are verified through an illustrative example with a 1.8-MJ initially stored energy. On the basis of these methods, parameter optimization in design phase and performance analysis in operation phase are conducted around the projectile muzzle kinetic energy $E_{k}$ and the system energy transfer efficiency $\eta $ . To be specific, the single-objective optimal solutions of $E_{k}$ and $\eta $ and the biobjective Pareto front of $E_{k}$ – $\eta $ are acquired by evolutionary computation. And the influence relations of certain system parameters on $E_{k}$ and $\eta $ are acquired by parameter sweep. The research methods and results in this paper have both theoretical and pragmatic values in improving the performance of the CPPS-based electromagnetic railgun system.

Study on the System Efficiency of the Capacitive Pulsed-Power Supply

Electromagnetic railgun systems based on capacitive pulsed-power supply (CPPS) have obtained widespread applications because of its obvious advantages over the inductive ones on mature technology, operational reliability, and feasible financial condition. However, the existing CPPS-based electromagnetic railgun system works with low efficiency. In this paper, systematical studies on the CPPS in the synchronously triggered electromagnetic railgun system with constant volume and in the time-delay-triggered electromagnetic railgun system with automatic segmentation are proposed, respectively. In the synchronously triggered electromagnetic railgun system, all pulse-forming units (PFUs) are supposed to be triggered synchronously and the load is simplified as a resistor first. Then, the system performance criteria, i.e., the launch velocity of the armature vend and the system efficiency η, are expressed as the function of four independent system variables: 1) the capacitance of each PFU C; 2) the precharged voltage U <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</sub> of capacitors; 3) the rail length l; and 4) the armature mass m. The relationship between η (or v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">end</sub> ) and any two independent variables can be found under the environment of MATLAB R2012a by fixing the other two parameters. The results are then verified under the environment of Simplorer 8. These figures can be used to instruct the design of the pulsed-power supply for a designated load or the railgun for a designated source. In the time-delay-triggered electromagnetic railgun system, the principle of automatic segmentation is proposed. According to the segmentation principle, the simulation results under the environment of Simplorer 8 are given for comparison. The paper can provide a theoretical foundation for the future designs to get higher system efficiency.

Development of a Long-Lifetime Spark Gap Switch and Its Trigger Generator for 2.0-MJ Capacitive Pulsed Power Supply Module

Starting from the updated requirements of an advanced laser system, a switch–trigger system for a 2.0-MJ pulsed power supply (PPS) module is developed. This paper discusses the design, construction, and testing of this switch–trigger system. The two-electrode construction for the spark gap switch is selected because of its superiority in terms of long working life, high peak currents, and fast rise time of currents. The trigger generator based on resonant charging of a pulse transformer is constructed. A magnetic isolator and a pressure controller are the auxiliary equipment of this system. In the section based on mathematical principles, the equations of the lifetime and stability of this spark gap switch with graphite electrodes are given. These expressions can be regarded as the design basis of the same type of switch. As for the trigger generator, the analysis states that an appropriate ratio can be obtained when using the resonant charging based on a core-type pulse transformer. The charging time is dependent on the leakage inductance and the capacitance of the primary and secondary capacitors. Extensive testing proves the operating parameters of the switches and the trigger generator. The measured discharge current waveform of the 2.0-MJ capacitive PPS module is demonstrated to be over 500 kA peak current and 500 ${\mu{\rm s}}$ pulse width. The life test proves that the switch–trigger system can support more than 200 kC transfer charge. By replacing the electrodes, the lifetime of this switch can be extended furthrer.

2.0 MJ脉冲功率源的500 kA气体开关系统

A switch-trigger system for a 2.0 MJ pulsed power supply module has been developed. This paper discusses the design, construction and testing of this switch-trigger system. In the section about the mathematical principles, the equations of the lifetime and stability of the spark gap switch and its trigger generator are given. Extensive testing has proved the operating parameters of the switch-trigger system. The measured discharge current of the 2.0 MJ capacitive pulsed power supply module is demonstrated to be over 500 kA and the transfer charge per shot is over 150 C. The switch trigger system can support more than 200 kC transfer charge, and it can support simultaneous operation of 20 pairs of xeon flash lamps in theory. Moreover, the lifetime of this switch can be extended by replacing the graphite electrodes adopted.

Design, Construction, and Testing of Switches and Trigger Generator for 1.2-MJ Capacitive Pulsed Power Supply Module

In this paper, starting from the project requirements, a 1.2-MJ pulsed power supply (PPS) module for a high-power laser system has been developed. The main circuit of this module consists of a high energy density capacitor bank, a spark gap switch, a magnetic switch, a trigger generator, and a load subsystem. Due to the superiority in the stability and service life, the two-electrode construction for the spark gap switch, high peak currents, and rise time of the currents is selected. Since a two-electrode spark gap switch has no separate trigger electrode and must be directly overvolted by the trigger generator, a small Marx generator has been designed and constructed for the advantage of the proven compactness and electrical performance. The effect of the magnetic switch represents a couple of functions. One is to block the triggering pulse produced by the Marx generator. Another is to permit the discharging current coming from the main capacitor bank. Finally, the measured discharge current waveform of the 1.2-MJ capacitive PPS module is demonstrated to be over a 300-kA peak current and a 500-μs pulsewidth. Moreover, the life test has proved that the switch-trigger system can support more than 1500 discharging processes.

Prototype Test and Manufacture of a Modular 12.5 MJ Capacitive Pulsed Power Supply

A new Pulsed High Magnetic Field Facility (PHMFF) is under construction at the Huazhong University of Science and Technology (HUST) in Wuhan, China. In order to provide a wide spectrum range, a modular capacitive pulsed power supply is designed to energize 12.5 MJ at 25 kV and a large variety of coils are designed for magnetic fields in the 50-80 T with pulse duration 15-200 ms, respectively. In order to energize multi-coil systems, the 12.5 MJ power supply is divided into 11 independent 1 MJ modules with a short circuit current of 44.7 kA each and 2 independent 0.75 MJ modules for 61.2 kA each. Each module is provided with its own protection inductor, thyristor switch, crowbar circuit, dump circuit, polarity-changing circuit, charging unit and switchgear. The current pulses can be modified in shape, amplitude and duration by varying the charging voltage, the number of modules and the crowbar resistors. For verifying the design scheme and gaining experience in the construction and operation of pulsed power supply, a 1 MJ prototype that is used to energize pulsed magnets for 50-72 T fields with reversible polarity has been developed. In this paper, after the introduction of the system configuration with different module types and system settings, the design of both the 1 MJ and 0.75 MJ modules is described in detail. Finally, test results of the 1 MJ prototype are presented.

Development of a Capacitive Pulsed Power Supply for High-Current High-Velocity Sliding Electrical Contact Studies

A pulsed power supply of a 1.5-MJ capacitor bank has been developed for high-current high-velocity sliding electrical contact studies in railgun launches. The system consists of 8 small modules, each with a capacitance of 15 mF, and one large module with a capacitance of 54 mF. All of nine modules use triggered spark gaps as the main switches. Various shapes of high-current pulse can be formed by controlling the charging voltage and firing time of each module. The small module has been designed for the maximum operating voltage of 5 kV, the peak current of 140 kA, the pulse rise time of 0.9 ms, in which semiconducting diode stack is used as crowbar switch. Since the large module has no crowbar switch and relatively small pulse forming inductance, it can supply high-amplitude oscillating current waveform. The effects of the large module are threefold. First, the large module provides a basic current on which the currents of small modules superimpose to form a nearly constant driving current of armature. Second, the oscillating nature of the current can drastically reduce the muzzle arc current; hence suppression of the muzzle arc can be obtained. Third, the crowbar switch can be removed and therefore the cost of the system can be reduced. The experiments were performed to verify the operation performances of the two kinds of modules, where the modules were discharged simultaneously and/or sequentially. The feasibility of large module on the muzzle arc control is also examined. The results of the experiments show that a total current of 400 kA with a 1.5 ms flat-top time can be obtained and all the modules show good performance during the railgun firing.