Yong Jin

Design of compact high-voltage capacitor charging power supply for pulsed power application

The pulsed power supply (PPS) with capacitor energy storage is the integral part of launch system, which is often used as energy storage element for electrothermal-chemical (ETC) launch, electromagnetic launch (EML), and other new-concept launch technology. In order to make capacitor charged rapidly, a novel capacitor charging power supply (CCPS) has been developed in this paper characterized by compact size, high charging power density and short charging time. Through comparison and analysis, a full-bridge series resonant zero current switching charging circuit, dry-type transformer, active cooling technology, anti-jamming technique, high integration structure design technology have been adopted. By analysis and calculation, the CCPS, which can satisfy quick and step by step charging to capacitor, with the charging current of about 5A, maximum working voltage of 12kV and charging voltage error of below 0.5%, has been designed. Finally, the CCPS has been developed and verified to be stable and reliable in the system by charging a 250kJ PPS module.

Energy skin effect of propellant particles in Electrothermal-Chemical Launcher

A numerical model of the radiation has been employed by a Monte Carlo method and statistical physics to simulate the process of a capillary plasma source for Electrothermal-Chemical (ETC) Launcher. The effect on propellants with different physical parameters is discussed. The plasma-propellant interaction is also discussed when combined with a thermal model. Results show that radiant energy only causes a small field around the plasma injector in the propellant bed. The responses of energy flux and propellant particles on radiation are both in the order of picosecond. The strong instantaneous radiation is responsible for the transmission of energy to the propellant particles leading to ignition. Compared with conventional ignition, the energy absorbed by propellant particles is used to increase quickly the temperature in the surface layer of propellant particles. This energy skin effect in the propellant particle surface appears to be the main cause of plasma ignition.

Research on Energy Loss Distribution of an Augmented Railgun

In order to analyze the characteristics of energy loss distribution of the electromagnetic launcher (EML), a calculation model considering contact resistance, contact velocity skin effect, and friction force was established. First, a comparison between the calculation results and the experimental results was employed to verify the accuracy and the reliability of this model. Second, the energy loss of every component of the EML system was calculated and analyzed. Based on this model, the energy loss distribution is easily obtained and visually understood, which is helpful for the EML optimization design. Finally, we discussed the difference of the energy loss distribution between an augmented railgun with stainless steel containment and without containment. Results show that the stainless steel containment decreases the launch efficiency and make more electric energy transformed into resistance loss in the EML system.

Applied Analysis of Electrothermal Chemical Launch Technology in 155mm Modular Charge Howitzer

Based on the research of large caliber modular charge howitzer and electrothermal-chemical (ETC) launch technology, the application advantages and prospects of ETC launch technology in a 155mm modular charge howitzer are discussed from the perspective of the technology development and actual applications, respectively. The analysis and discussion results show that the ETC launch technology will effectively improve the chamber combustion stability and interior ballistics consistency of the modular charge howitzer. It also will enhance the whole operational effectiveness including both firing range and accuracy. The ETC launch technology is an important development route for the future modular charge howitzer.

Research Progress of Pressure Testing Technology for Electrothermal-Chemical Launch

A strong electromagnetic interference is always appeared in electrothermal-chemical launching process. Several charging and discharging of high voltages can cause the ground voltage floating. These often produce a serious impact on the nearby testing devices, influence the measurement accuracy of the bore pressure, and even damage the measuring equipment. In the last dozen years, three kinds of pressure testing schemes are designed, which one is the on-site storage measurement, another is the dual insurance measurement technology that combined the site storage measurement with digital fiber communication technology, the third is the real-time measuring system of in-situ distributed test and remote synchronization detection for electrothermal-chemical gun (ETCG) chamber pressure. The pressure test system is gradually perfected, which can solve the problem of EMI, and the multi physical parameters (plasma load voltage and current, bore pressure, muzzle pressure and muzzle velocity signals) are unified in the same time axis.

Development and properties of a 500KJ pulsed power supply

A500kJ capacitive pulsed power supply (PPS), consisting of one constant current charger and two pulsed power modules (PPM), has been designed and developed. The energy storage density of the whole PPS is about 1MJ/m3. The output current of the constant current charger in the PPS is over 12A, and this device has floating charge function for capacitors when the PPS is in the process of waiting trigger discharge. The PPS can work independently or as a basic unit in a large pulsed power supply system used for electromagnetic launch (EML). The main components in a PPM are energy storage capacitor (10kV/250kJ), pulse-shaping inductor (50μH), pulse thyristor and crowbar diode. In this paper we describe the structural characteristics of 250kJ PPM and the design features of its main components. The test operation result of 250kJ PPM is also given. Test results show that the PPMs output peak current is nearly 90kA.

Measurement of electromagnetic radiation dissipation in pulse power supply discharging

A 2MJ pulse power supply (PPS) has been designed to support the development and evaluation of candidate propellants for an Electrothermal-Chemical (ETC) gun. The overall power system consists of twenty capacitive 100kJ pulse power modules. Each capacitor bank of the 100kJ module consists of two 12kV 50kJ capacitors. A triggered vacuum switch (TVS) was adopted as the main pulse power-closing switch. Electromagnetic radiation dissipation is always observed in pulse power supply discharging experiments. This kind of pulse radiate dissipation always has an influence in discharging peak current and load energy deposition. A copper wire sensor is designed and employed to measure the radiation intensity distributions near the facility. And the whole systems radiate dissipation is also obtained in calculations. Results show that radiation dissipation is always detected at the TVS triggering moment in synchronized discharging model. The received signal has a main frequency nearly 125kHz, and rapidly oscillating damped in 1ms. The radiation dissipation energy is nearly 3% in the whole discharging energy and the discharge efficiency keeps more than 75%.