Impact of stray inductances of the power loop on false trigger‐on in the zero‐voltage‐switching full‐bridge converter

Here, we propose an exhaustive theoretical investigation and experimental verification of the false trigger‐on phenomenon, which would lead to the interaction between the upper and lower devices during the switching transient, in the zero‐voltage‐switching (ZVS) full‐bridge converter. An equivalent model of the converter, which takes not only the parasitic capacitors of the metal–oxide–semiconductor field‐effect transistors into account but also the stray inductances of the main circuit, is presented. Based on the model, a comprehensive study of the false trigger‐on phenomenon is carried out. According to the analysis results, the stray inductances of the metal–oxide–semiconductor field‐effect transistors have negligible influence on the false trigger‐on phenomena since the soft‐switching is realized. The false trigger‐on phenomenon is induced by the stray inductances of the main circuit. Moreover, the arrangement of the switching sequence would cause significant discriminations in the false trigger‐on phenomena because of the specific working mode of the ZVS full‐bridge converter. According to the investigation results, optimization methods are presented to suppress the induced voltage. At last, the theoretical investigations are verified by tests of a ZVS full‐bridge converter. Copyright © 2016 John Wiley & Sons, Ltd.     

无线传感器网络混合触发一致性时间同步

针对无线传感器节点能量有限、无线通信环境差的特点,将事件触发通信机制应用于无线传感器网络(WSNs)的时间同步中,提出一种混合触发一致性时间同步(MTCTS)算法,并研究同步能耗的降低方法及传输延迟和数据丢包对同步算法的影响。节点的时钟特性建模成二阶状态方程,每个节点通过与其邻居节点交换本地时间这一状态信息获得同步控制输入,从而实现WSNs的时间同步。在所提出的一致性同步算法中,每个节点周期性地更新状态,根据当前状态是否满足给定的事件触发条件去触发通信事件的发生,如此降低通信事件的发生频率。在假定传输延迟服从指数分布和所有节点丢包率相同的情况下,进一步研究了传输延迟、信息丢包对同步精度和算法收敛性的影响。实验和MATLAB仿真验证了所提算法的有效性,并通过仿真确定出了传输延迟和丢包率的上界。     

多传感轨道扣件检测的数据同步采集系统设计

针对轨道扣件检测的多传感数据同步采集,首先,在分析线阵CCD相机成像原理的基础上,根据系统的要求对相机的关键参数进行了选择并设计了采集方案。然后,设计了传感器的信号调理电路,包括电平调整电路以及抗混叠滤波器的设计,提高了传感器的抗干扰能力。并通过STM32获取光电编码器的等间隔脉冲信息,对各个传感器进行触发控制,设计了线阵相机与惯性传感器的同步触发方案。最后,编写了上位机软件实现了数据的同步采集。实验结果表明,该系统能够精确采集各传感器的数据,具有较强的抗干扰能力和稳定性。     

蓄电池机车新型直流斩波控制触发板的设计

介绍蓄电池机车新型控制触发板的设计方法。     

气体开关触发间隙与过压间隙击穿特性研究

为研究快脉冲直线变压器驱动源（FLTD）多间隙气体开关的触发击穿特性，针对一种环形电极两间隙等效实验开关，开展不同触发电压、工作系数和电极材料下的击穿特性实验，对比两个间隙的击穿延时和抖动，分析间隙击穿特性的主要影响因素和作用机制。实验结果表明：触发间隙击穿延时主要受触发电压影响，而工作系数是过压间隙击穿延时的主要影响因素；开关抖动主要来自于触发间隙，触发间隙抖动随触发电压的增大明显减小，过压间隙抖动基本不随触发电压和工作系数变化且维持在较低值；石墨电极开关的击穿延时和抖动明显小于不锈钢、黄铜和钨铜电极开关，具有良好的触发击穿性能。通过分析指出，是否有预电离可能是两个间隙击穿特性差异的主要原因。     

Study on the plasma generation characteristics of an induction-triggered coaxial pulsed plasma thruster

At present,spark plugs are used to trigger discharge in pulsed plasma thrusters (PPT),which are known to be life-limiting components due to plasma corrosion and carbon deposition.A strong electric field could be formed in a cathode triple junction (CTJ) to achieve a trigger function under vacuum conditions.We propose an induction-triggered electrode structure on the basis of the CTJ trigger principle.The induction-triggered electrode structure could increase the electric field strength of the CTJ without changing the voltage between electrodes,contributing to a reduction in the electrode breakdown voltage.Additionally,it can maintain the plasma generation effect when the breakdown voltage is reduced in the discharge experiments.The induction-triggered electrode structure could ensure an effective trigger when the ablation distance of Teflon increases,and the magnetic field produced by the discharge current could further improve the plasma density and propagation velocity.The induction-triggered coaxial PPT we propose has a simplified trigger structure,and it is an effective attempt to optimize the micro-satellite thruster.     

dsPIC30F6014的晶闸管触发电路装置设计

介绍了一种基于dsPIC30F6014单片机控制的三相晶闸管触发实验装置,详细阐述了其软硬件结构。测试实验证明,该装置电路简单,产生的触发脉冲稳定性好、触发精度高、易于调试、操作方便、具有实用价值,能够进一步开发用于实验教学。     

An improved technology for eliminating nondeterministic latency in the L1 trigger system

Gamma Ray Array Detector(GRAD) is one of external target facility subsystems in the Cooling Storage Ring on the Heavy Ion Research Facility at Lanzhou(HIRFL-CSR).The trigger subsystem of GRAD is required to make a fast L1 trigger decision with a fixed latency for the data acquisition.Because the hit signals from the detector are asynchronous with the local clock of the trigger system,a nondeterministic latency(the value changes between zero and one clock period) is generated when the synchronous receivers of the conventional trigger system process the hit signals.In this paper,an improved trigger logic based on a field-programmable gate array is developed,and comprised of zero-delay broadening circuits as receivers and an improved adding circuit designed for the new receivers.Software simulation and experimental measurement have been conducted.Comparison with the conventional trigger logic,the improved trigger logic has the advantage of eliminating the nondeterministic latency and reducing the total processing latency.     

如何利用PowerPoint实现交互

PowerPoint是大家比较熟悉的Office办公软件之一,是大多数企事业单位日常办公中必不可少的应用软件,通过介绍演示文稿的类型入手引出演示文稿对交互性的需求,并具体介绍了演示文稿的适用范围,在演示文稿的交互实现上,通过超链接、触发器和控件与VB代码的方式来满足交互性需求。     

远程多路遥控起爆器的设计

为适应军事技术向信息化、智能化方向发展的趋势,研究设计了一种多路遥控起爆器。论述了系统设计的总体方案,遥控发射单元、无线接收起爆单元的设计及滚动编解码技术的原理。该系统体积小、质量轻、可靠性高、有效控制距离范围广、抗干扰能力强。