Power supply considerations for EM launchers

According to the characteristics of rapid response and low sensitivity of the Hall element, combined with the data processing methods of sample/hold and AD conversion widely used in engineering applications at present, it is explored to drive the Hall element by pulsed power supply, and increase the magnetic sensitivity of Hall element by sampling at the peak voltage. The conditions about the temperature rise of the Hall element driven by pulsed power supply are theoretically analyzed. The equivalent relationship of temperature rise between pulsed and DC power supply is put forward. It is pointed out that the peak power and peak voltage can be converted into equivalent power and equivalent voltage to reflect the temperature rise of the Hall element. The experimental results verify the equivalent relationship of the temperature rise.

Background: High-temperature alloys, such as the nickel-based alloy, have become the main materials for core components in the aerospace field because of their high strength and good toughness. Therefore, how to improve the machining accuracy and stability of electrochemical machining (ECM) of small deep holes on nickel-based alloy is an important topic for studies. The instantaneous high-density current during the pulse width of pulse ECM is beneficial to the dissolution of nickel-based alloy. Many experts and scholars have studied pulse ECM of small deep holes. Objective: The purpose of this article is to propose and design a positive and negative pulse (PANP) power supply to study the accuracy and stability of ECM of small deep holes on the nickel-based alloy. Methods: First of all, an H-bridge composed of four MOSFET switches is designed to achieve PANP output in the main circuit of the power supply. Then, this article discusses the influence of the ratio of positive and negative pulses on short circuits, the influence of the ratio of positive and negative pulses on the mass removal rate, and the influence of the electrolyte concentration and pulse width on the mass removal rate. Finally, according to the obtained optimal parameters, the influence of the electrolyte pressure on the average radial overcut of hole depth is analyzed. Results: The experimental results show that the short-circuit frequency is reduced by more than 50% compared with non-negative pulses power supply; the ratio of positive and negative pulses, pulse width, and electrolyte concentration and pressure were optimized by experiments in order to improve the mass removal rate of the workpiece and the average radial overcut of hole depth. Conclusion: The designed PANP power supply can improve the machining accuracy and stability of ECM of small deep holes on the nickel-based alloy.

Summary form only given. The control of pulsed power supplies is difficult due to factors such as short timescales and complex system dynamics. The steady state and time averaged models that are often used to design controllers for standard power supply applications are not sufficient for pulsed power applications. Open loop controllers are often used in pulsed power control applications, and the control inputs are designed offline, often using empirical techniques based on system simulations, but these techniques are not optimal and are not robust. We present a hvbrid system model of the pulsed power system and apply an optimal control technique that can be implemented as a state feedback controller. The solution provides a robust and computationally efficient method for controlling pulsed power supplies.

The authors have attempted to obtain information on the source plasma component of the electrothermal launcher by extending their previous model to include a momentum balance equation. A zero-dimensional time-dependent code and its application to simulation of the electrothermal launcher are given. The properties of the plasma are evaluated self-consistently with models for electrical resistivity, the ablation process, and ionization of the plasma for the plasma source component of electrothermal launchers. This is necessary in order to model the higher energies, larger source volumes, and pressure oscillations present in electrothermal chemical launchers. The code developed for this purpose is benchmarked against another theoretical analysis that is steady state in nature. A scaling law for the vapor shielding process is derived from the benchmark case, and is used for analysis of the desired time-dependent problem. The results are presented for two experimental cases of interest.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Due to the influence of electromagnetic force, sliding riction, air resistance and other factors, the dummy load of the pulsed power supply (PS) changes with the launch process in the electromagnetic railgun launch system, the characteristics of pulsed PS can not be accurately studied using the fixed resistance and inductance to simulate the load of pulsed PS. Therefore, the mathematical model of the pulsed PS based on the multiple high-temperature superconducting pulsed power transformer (HTSPPT) was built, in this model, a dynamic model including various forces simulates the load. The simulation results show that if the influence of various forces is ignored, the characteristic parameters of pulse PS will have large errors.

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.

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

본 논문은 트리거 시간을 조절하여 펄스 성형이 가능한 150 MW 펄스 파워 시스템의 설계와 동작특성을 알아보았다. 이 시스템은 2개의 커패시터 뱅크 모듈로 구성되어 있고, 각 커패시터 뱅크 모듈은 병렬로 연결되어 있다. 그리고 커패시터 뱅크 모듈은 메인스위치, 커패시터, 에너지 덤프회로, 크로바 회로, 펄스 성형 인덕터로 구성되어 있다. 또한 이 시스템의 모듈 선택과 트리거 시간은 트리거 제어부에서 조정된다. Pspice 시뮬레이션은 실험회로의 결과를 예측하고, 시스템의 구성품의 파라미터를 결정하기 위한 것으로 사용하였다. 실험 결과, 시뮬레이션은 실험결과와 잘 일치하였다. 출력 전류의 펄스폭은 커패시터 뱅크 모듈에서의 순간적 점화 시간 제어로 300~650 us의 펄스폭이 형성되었다. 그리고 최대 전류값은 2개의 커패시터 뱅크 모듈이 동시에 트리거 되었을 때 약 40 kA 정도이다. 이 150 MW 펄스 파워 시스템은 파암 전원, Rail Gun, Coil Gun, 나노분말 제조, HPM 등과 같은 대전류 펄스 파워 시스템에 적용할 수 있다. This paper presents design and operational characteristics of 150 MW pulse power system for high current pulse forming network to control trigger time. The system is composed of two capacitor bank modules. Each capacitor bank module consist of a trigger vacuum switch, 9k 33kJ capacitor, an energy dump circuit, a crowbar circuit and a pulse shaping inductor and is connected in parallel. It is controlled by trigger controller to select operational module and determine triggering time. Pspice simulation was conducted about determining parameters of components such as crowbar circuit, capacitor, pulse forming inductor, trigger vacuum switch and predicting results of experiment circuit. The result of the experiment was in good agreement with the result of the simulation. The various current shapes with 300~650 us pulse width is formed by sequential firing time control of capacitor bank module. The maximum current is about 40 kA during simultaneous triggering of two capacitor bank modules. The developed 150 MW pulse power system can be applied to high current pulse power system such as rock fragmentation power sources, Rail gun, Coil gun, nano-powers, high power microwave.

The authors review the progress in the RARDE (Royal Armament Research and Development Establishment) electromagnetic gun (REMGUN) program. They cover research on both railgun and LIA (linear induction accelerator) technology, including work on modeling, projectile/barrel interactions armatures, switching, and instrumentation. They also describe the major research facilities. Progress is reported in the identification and development of single-shot switches, integrated switch/barrel concepts, armatures and pulse power supplies as well as the integration of railgun components. LIA research has concentrated on launcher design and projectile/barrel interactions, highlighting the problems of pulse power systems for this form of electromagnetic launcher.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

The pulsed power supply equipment belongs to the basic technological systems intended for implementing the required scenarios of changing currents in magnetic coils. The accuracy of implementing these scenarios directly determines the possibility of attaining the plasma breakdown and the required ultimate plasma parameters. Given the uniqueness of each facility under construction in the world and the installed capacity of the electrotechnical equipment applied in the power supply configuration, one can state with confidence that the construction of similar power supply complexes and their control systems, the optimization of their electrotechnical parameters, and the subsequent accident-free operation are vital tasks in mastering controlled thermonuclear fusion technologies. This paper describes the pulsed power supply system of the KTM tokamak (Kazakhstan) designed for material testing, the digital control system for its power conversion equipment, electrotechnical solutions adopted in the design of the KTM tokamak pulsed power supply system, and findings of tests of some items of equipment and their components. The tests have demonstrated sufficient efficiency of the adopted electrotechnical solutions and the possibility of applying them to implement the pulsed power supply systems for small and medium sized tokamaks.

Novel coronavirus pneumonia affects the health of people all over the world. In this study, UV pulse high-light sterilization technology was used to combat coronavirus. The light source of the ultraviolet pulsed high-light disinfection robot is a kind of high-brightness flash light source using pulsed xenon lamps as the output load. This paper developed a pulsed xenon lamp power supply with a high-voltage pulse synchronous trigger function, a DC charging voltage of 1kV-3kV, an output pulse current range of 1kA-3kA, and a pulse width of 50μS for a pulsed xenon lamp with a 196mm×Φ10mm and a resistivity of 12Ω⋅A1/2. This paper presented the experimental results of charging voltage of 1kV, output pulse current peak value of 1kA, and pulse width of 50μS. The power supply design was based on the phase-shifting voltage regulation mode of UC3825 control power MOS tube, through the sampling isolation module and the closed-loop feedback formed by STM32 control, the energy storage capacitor was linearly charged through the DC voltage sampling and voltage regulation control module; the trigger pulse signal was generated by the SCR switch, and the xenon lamp was turned on and emits flash light after the pulse transformer was boosted. The sample test results verified the feasibility of the power supply design principles and technical solutions.

With the development of the global first fourth electron cyclotron resonance (FECR), plasma of highly charged ions produced under high microwave frequencies required to be constrained strictly by symmetric high magnetic field. Using pulsed power supply to generate the magnetic field has cost-effective advantage over superconducting power supply. In this paper, a pulsed power supply is utilized to generate symmetric high magnetic field. The pulsed power supply must provide large inductive loads with a fast pulse current ramping from 0A to 2700A between 50 ms and 70ms. The stability of current is 6×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> and the repeatability of current is about 2×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup> at the flat top current waveform. For this purpose, a digital controller based on Xilinx 7000 FPGA is designed and implements a control strategy of double current loop in series. The experiment results show that the index of pulsed power supply is successfully fulfilled.

Traps equipped with low-power LEDs are very promising for use in insect pest control due to their safety for the non-target entomofauna. However, the level of natural illumination at night at high latitudes varies greatly and the attractiveness of low-power LEDs in early summer (i. e. during the period of white nights) becomes too weak to ensure acceptable catch of harmful insects in traps. The purpose of this article is to illustrate a successful attempt, using the example of the diamondback moth, Plutella xylostella (L.), to enhance the attractive effect of low-power LEDs by replacing their direct current supply with a high-frequency pulsed (30 kHz) power supply. Diamondback moth adults were collected in the vicinity of St. Petersburg in 2020–2024 using Delta plastic traps equipped with LEDs and a synthetic sex attractant as a control. The results obtained proved that upgrade of LEDs power supply provides significant increase in diamondback moth adult catch by light traps, exactly 4.57 times during the period of white nights, 3.11 times during the dark nights following them, and 4.45 times during the summer as a whole. The results achieved are important not only from a practical point of view, but also have theoretical value, since the effect of flickering light on insect behaviour has been very insufficiently studied.

Circuit considerations which are critical for minimizing electromagnetic interference in instrumentation amplifier designs are discussed. A radiofrequency isolation amplifier is used to illustrate the concepts. Component selection and circuit details of the completed device are discussed. It is shown how these affect both amplitude noise and phase noise performance. Active device, capacitor, inductor, resistor, and power supply considerations are discussed. >

3D asymmetric magnetic reconnection is an important investigation of the Space Plasma Environment Research Facility, which is being built as a user facility at the Harbin Institute of Technology in China. Four magnetosheath coils, which consist of Poloidal Field (labeled PF) coils and Toroidal Field (labeled TF) coils, are used to generate the magnetic field and plasma environment for the reconnecting experiment. A capacitor-based pulsed power supply (PPS) system with a modular design is developed to excite the magnetosheath coils to generate the required amplitude and duration of the magnetic field. The PPS system includes the PF PPS and TF PPS, which include four sets of PPSs, respectively. Each set of PF PPS and TF PPS consists of nine modules and four modules, respectively, and each module consists of a charge and discharge unit. The PF PPS can provide a pulsed current of no less than 360 kA for the corresponding PF 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 TF PPS can provide a pulsed current of no less than 200 kA for the corresponding TF coil at 0.08ms 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 1.6ms. The detailed design of the PPS has been discussed in this paper, and the detailed design of the main components in the discharge unit of the PPS is also given in this paper. Finally, the discharge tests of all the PPSs are carried out to verify the design of the PPSs, and the results of the PPSs in discharge tests indicate that all the PPSs meet the design requirements.