Capacitor-based pulsed power supply(PPS)is widely used in fields related to electromagnetic launch,plasma,and materials'synthesis,modification and processing.As industrial applications place higher requirements on...Capacitor-based pulsed power supply(PPS)is widely used in fields related to electromagnetic launch,plasma,and materials'synthesis,modification and processing.As industrial applications place higher requirements on compact and portable pulsed power supplies,the National Key Laboratory of Transient Physics(NKLTP)recently developed a pulsed power supply consisting of a set of compact pulse-forming units(PFU),each with a capacitor energy storage of 220 kJ.This integrated PPS comes with a complete system configuration,a miniature compact structure,a high rate of repetition,and high power,with energy storage density exceeding 1.2 MJ/m^(3).This paper describes the device-level design of the unit,the system layout,the control system,the thermal management system,and the experimental results of the pulsed power supply.The experimental results verified the good reliability of the PPS at high repetition rates with each unit module delivering an output current of more than 100 kA.Additionally,flexible current pulse shapes can be formed by setting the charging voltage and the trigger sequence of the PFUs.The pulse forming network(PFN)developed from these PFUs was successfully applied to electromagnetic launch.展开更多
On the basis of the relationship between the Hamiltonian of spin 1/2 quantum system under control and the energy level structure and transitions, a radio frequency pulse sequence is designed using intuitive and half c...On the basis of the relationship between the Hamiltonian of spin 1/2 quantum system under control and the energy level structure and transitions, a radio frequency pulse sequence is designed using intuitive and half counter-intuitive sequences of pulse to transfer the population of the 3-qubit system coherently. The effectiveness of the designed control sequence is verified through the system simulation experiment of the evolution of state. In principle, the design method of the control pulse sequence proposed can be generalized to use in the quantum systems of higher dimension.展开更多
An electromagnetic coupling mathematical model is established by finite element method and is verified by the contrastive experiments of copper matrix Ni-TiN cylindrical coating electrode,copper electrode and Cu50 W e...An electromagnetic coupling mathematical model is established by finite element method and is verified by the contrastive experiments of copper matrix Ni-TiN cylindrical coating electrode,copper electrode and Cu50 W electrode.The wear mechanism of Ni-TiN/Cu composite electrode in the case of high-frequency pulse current is studied,and the influence of the fluctuation frequency of discharge current on electrode wear in micro-EDM is found out.Compared with the electrode made from homogeneous material,the high frequency electromagnetic properties of Ni-TiN composite layer can be used effectively to inhibit the effect of high frequency pulse on the electrode and improve the distribution trend of current density.展开更多
For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control （AGC） circuit and the survivability of the prime circuit under strong interferenc...For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control （AGC） circuit and the survivability of the prime circuit under strong interference are analyzed by simulations and experiments. An AGC simulation model based on the voltage control amplifier VCA810 prototype is proposed. Then static and dynamic simulations are realized with single frequency signal and linear frequency modulated （LFM） signal commonly used in the active sonar. Based on intense sound pulse （ISP） interference experiments, the real-time response characteristics of each module of the receiver are studied to verify the correctness of the model as well as the simulation results. Simulation and experiment results show that, under 252 dB/20 μs ISP interference, the specific sonar receiver will produce sustained cut top oscillation above 30 ms, which may affect the receiver and block the regular sonar signal.展开更多
新型脉冲功率设备对直流侧母线电压提出较高的性能要求,为减小脉冲负载对直流电压波动率的影响,建立带脉冲负载三相整流器拓扑结构及数学模型,并在现有无源控制(passivity based control,PBC)设计的基础上,以保证系统稳定性为前提,提出...新型脉冲功率设备对直流侧母线电压提出较高的性能要求,为减小脉冲负载对直流电压波动率的影响,建立带脉冲负载三相整流器拓扑结构及数学模型,并在现有无源控制(passivity based control,PBC)设计的基础上,以保证系统稳定性为前提,提出注入虚拟储能的无源控制算法(virtual energy storage injection PBC,VESI-PBC),该算法以提高能量函数收敛速度为目标,可有效降低直流母线电压波动率,提高抗负载扰动能力。分别基于根轨迹法和时域分析法,讨论VESI-PBC引入储能矩阵后,增大虚拟电感值L_(n)对系统的稳定性和动态性能的影响。为满足直流侧性能要求和保证系统稳定性,利用脉冲负载对直流电压波动率的影响规律,提出L_(n)自适应选取函数f(f_(PL)),使L_(n)自适应平衡系统高频毛刺和低频强脉冲冲击的不同需求。最后,通过仿真及实际试验,验证VESI-PBC算法对减小直流母线电压波动率的有效性,并指出该算法的实质是控制内环电流超前响应直流电压的动态变化及其变化趋势,由此具有较强的抗负载扰动能力,适用于负载脉冲功率等级高、动态特性强烈的场合。展开更多
为了提高微波光子矢量网络分析仪(MPVNA)进行脉冲测量时的动态范围,提出了一种软件门控方案,该方案利用临时闲置接收通道接收与脉冲激励产生的控制信号同源的脉冲方波,以此生成门控信号。通过这个门控信号对采集到的待测器件脉冲响应进...为了提高微波光子矢量网络分析仪(MPVNA)进行脉冲测量时的动态范围,提出了一种软件门控方案,该方案利用临时闲置接收通道接收与脉冲激励产生的控制信号同源的脉冲方波,以此生成门控信号。通过这个门控信号对采集到的待测器件脉冲响应进行控制,有效提高了信噪比和测量的动态范围。对10 GHz带通滤波器的脉冲散射参数(S参数)进行了测量,实验结果表明:在占空比为1%的脉冲激励下,应用软件门控的测量动态范围相比未应用门控时的提高了约20 d B;门控处理后测得的S11和S22参数曲线也因为信噪比的提升更加光滑和稳定。展开更多
基金financial support from the National Key Laboratory of Transient Physics,Nanjing University of Science and Technology(Grant No.6142604230101)Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(Grant Nos.KYCX20_0321 and KYCX20_0322).
文摘Capacitor-based pulsed power supply(PPS)is widely used in fields related to electromagnetic launch,plasma,and materials'synthesis,modification and processing.As industrial applications place higher requirements on compact and portable pulsed power supplies,the National Key Laboratory of Transient Physics(NKLTP)recently developed a pulsed power supply consisting of a set of compact pulse-forming units(PFU),each with a capacitor energy storage of 220 kJ.This integrated PPS comes with a complete system configuration,a miniature compact structure,a high rate of repetition,and high power,with energy storage density exceeding 1.2 MJ/m^(3).This paper describes the device-level design of the unit,the system layout,the control system,the thermal management system,and the experimental results of the pulsed power supply.The experimental results verified the good reliability of the PPS at high repetition rates with each unit module delivering an output current of more than 100 kA.Additionally,flexible current pulse shapes can be formed by setting the charging voltage and the trigger sequence of the PFUs.The pulse forming network(PFN)developed from these PFUs was successfully applied to electromagnetic launch.
基金supported by the National Natural Science Foundation of China (60774098)the National Key Basic Research Program (2006922004)
文摘On the basis of the relationship between the Hamiltonian of spin 1/2 quantum system under control and the energy level structure and transitions, a radio frequency pulse sequence is designed using intuitive and half counter-intuitive sequences of pulse to transfer the population of the 3-qubit system coherently. The effectiveness of the designed control sequence is verified through the system simulation experiment of the evolution of state. In principle, the design method of the control pulse sequence proposed can be generalized to use in the quantum systems of higher dimension.
基金the National Natural Science Foundation of China for financially supporting this research through project No.51005027
文摘An electromagnetic coupling mathematical model is established by finite element method and is verified by the contrastive experiments of copper matrix Ni-TiN cylindrical coating electrode,copper electrode and Cu50 W electrode.The wear mechanism of Ni-TiN/Cu composite electrode in the case of high-frequency pulse current is studied,and the influence of the fluctuation frequency of discharge current on electrode wear in micro-EDM is found out.Compared with the electrode made from homogeneous material,the high frequency electromagnetic properties of Ni-TiN composite layer can be used effectively to inhibit the effect of high frequency pulse on the electrode and improve the distribution trend of current density.
基金supported by the National Natural Science Foundation of China (10974154)the National Innovation Project of China for Undergraduates (101069935)
文摘For anti-jamming and anti-countermeasure techniques of the sonar receiver, the response characteristics of the automatic gain control （AGC） circuit and the survivability of the prime circuit under strong interference are analyzed by simulations and experiments. An AGC simulation model based on the voltage control amplifier VCA810 prototype is proposed. Then static and dynamic simulations are realized with single frequency signal and linear frequency modulated （LFM） signal commonly used in the active sonar. Based on intense sound pulse （ISP） interference experiments, the real-time response characteristics of each module of the receiver are studied to verify the correctness of the model as well as the simulation results. Simulation and experiment results show that, under 252 dB/20 μs ISP interference, the specific sonar receiver will produce sustained cut top oscillation above 30 ms, which may affect the receiver and block the regular sonar signal.
文摘新型脉冲功率设备对直流侧母线电压提出较高的性能要求,为减小脉冲负载对直流电压波动率的影响,建立带脉冲负载三相整流器拓扑结构及数学模型,并在现有无源控制(passivity based control,PBC)设计的基础上,以保证系统稳定性为前提,提出注入虚拟储能的无源控制算法(virtual energy storage injection PBC,VESI-PBC),该算法以提高能量函数收敛速度为目标,可有效降低直流母线电压波动率,提高抗负载扰动能力。分别基于根轨迹法和时域分析法,讨论VESI-PBC引入储能矩阵后,增大虚拟电感值L_(n)对系统的稳定性和动态性能的影响。为满足直流侧性能要求和保证系统稳定性,利用脉冲负载对直流电压波动率的影响规律,提出L_(n)自适应选取函数f(f_(PL)),使L_(n)自适应平衡系统高频毛刺和低频强脉冲冲击的不同需求。最后,通过仿真及实际试验,验证VESI-PBC算法对减小直流母线电压波动率的有效性,并指出该算法的实质是控制内环电流超前响应直流电压的动态变化及其变化趋势,由此具有较强的抗负载扰动能力,适用于负载脉冲功率等级高、动态特性强烈的场合。
文摘为了提高微波光子矢量网络分析仪(MPVNA)进行脉冲测量时的动态范围,提出了一种软件门控方案,该方案利用临时闲置接收通道接收与脉冲激励产生的控制信号同源的脉冲方波,以此生成门控信号。通过这个门控信号对采集到的待测器件脉冲响应进行控制,有效提高了信噪比和测量的动态范围。对10 GHz带通滤波器的脉冲散射参数(S参数)进行了测量,实验结果表明:在占空比为1%的脉冲激励下,应用软件门控的测量动态范围相比未应用门控时的提高了约20 d B;门控处理后测得的S11和S22参数曲线也因为信噪比的提升更加光滑和稳定。
