EPICS实现ECR离子源高压电源控制

本文在EPICS架构下设计了ECR离子源高压电源的控制逻辑结构,开发了支持其控制器的Record类型,完成了其IOC端的代码实现,实现了ECR离子源高压电源的控制并在现场运行。     

基于FPGA的PSM高压电源脉冲控制器的研制

文章介绍了在PSM高压电源控制系统中,应用FPGA实现PSM模块步进时间间隔最小为1μs的精确定时.通过控制各个PSM模块的开通与关断,实现高压的输出与关闭.文章从硬件平台选择、控制逻辑设计、实验数据分析等方面着手,介绍了PSM电源脉冲控制器的设计与实现.实验表明:该脉冲控制器实时性良好,性能稳定可靠,满足PSM高压电源的控制需求.     

G-M计数管新型直流高压电源设计

G-M计数管工作需要性能稳定的直流高压电源供电。该直流高压电源利用输出采样与基准电压比较负反馈实现高压稳定控制,比较不同闭环放大倍数下直流高压电源性能,采取优化闭环放大倍数。该直流高压电源具有结构简单、体积较小、低纹波等特点,其输出电压在0~1 100 V范围内连续可调。测试结果表明:当高压典型输出电压为400 V时,电压稳定度可达0.17%,输出电压纹波峰最低峰值为62 m V,可满足G-M计数管的需求。     

低功耗高压稳定电源

闪烁计数器是一种应用十分广泛的核粒子探测器,它有较高的探测效率,但在工作时要有高压电源供给分压电阻一定的电流。因此闪烁计数器用于携带仪器时,低功耗高压电源成为电路设计中的主要课题。本文将讨论获得低功耗高稳定高压电源的电路措施。 低压供电的高压稳定电源通常由直流变换器、基准电压源、取样电路和控制放大器组     

ECRH系统中MOD控制系统的研究

负高压电源系统是电子回旋共振加热（ECRH）系统的重要组成部分,而MOD控制系统则是负高压电源系统乃至整个ECRH系统运行的关键。介绍了系统的理论背景和工作原理,并详细阐述了该控制系统的硬件结构和软件流程。实验运行表明,该系统运行稳定、控制正确、保护迅速可靠。     

一种单片机控制的高压开关电源

针对X射线荧光分析装置对供电高压电源在效率、体积和智能控制等方面的要求,研制了一种以单片机和脉宽调制(PMW)技术为基础的高压电源.以单片机89C52为控制主体,采用单端式推动、PID算法稳压控制,经变压器和倍压整流后输出高压.电源输出在0～50 kV连续可调,且体积小、效率高、长期运行性能稳定.     

X线管高压电源打火自恢复保护电路研究

X线管在生产制造和使用过程中,一般处于高压加载的工作条件下,经常会出现打火放电现象。结合模糊PID控制技术和触发定时电路设计了一种高压电源打火自恢复保护电路。当X射线源控制系统接收到打火放电信号脉冲时,能自动降低高压电源输出至预设的安全值并保持此功率锁定状态,直至打火结束后恢复输出。X线管检测老练平台应用实验表明,在非必须关断、重启的情况下,该电路可显著提升X线管高压电源的动态性能,提高X线管老练工艺效率,保护设备安全,同时也可适用于各类X光机高压电源设计应用场合。     

3He中子探测器小型直流高压电源设计

介绍了低纹波、低功耗³He中子探测小型直流高压电源的设计。该直流高压电源核心部分采用MAX1771芯片、电感和MOS管构成自激振荡,并经后级的多级倍压电路进一步放大输出电压,滤波电路选用π型滤波网络,纹波可控制在20 mV以内。测试结果表明:该直流高压电源输出电压范围为1.0～1.5 kV可调,输出电流最大可达到0.535 mA,静态功率损耗最大为0.3 W,总体指标达到³He中子探测器的电源要求。     

中子发生器靶高压电源优化设计

研发小型密封可控中子发生器替代同位素中子源可降低诸多环境和社会风险。为实现中子发生器的小型化,关键在于减小靶高压电源体积。对靶高压电源的驱动电路、倍压电路以及机械结构进行了优化设计。经测试验证实现了靶高压额定电压/电流-150 kV/200μA,靶高压电源常温连续工作稳定性:24 h,≤±1%。完成了靶高压电源设计及优化。为后续研发高性能中子发生器奠定了坚实的基础。     

基于脉冲步进调制技术的ECRH全固态阳极高压电源控制系统设计

电子回旋共振管是产生高功率毫米微波的真空电子器件,在可控热核聚变研究、雷达等领域中有重要的应用。针对可控热核聚变研究中1 MW/105 GHz回旋管加热系统阳极电源幅度可调且调制的要求,使用高频开关电源技术和脉冲步进调制技术（PSM）研制了全固态阳极高压电源。重点阐述了阳极高压电源实现稳压、调制、前沿时间可调功能的软件控制算法,并通过实验对设计进行了验证。该阳极高压电源具有单脉冲、多脉冲调制和六电平预置波形等3种模式输出功能;输出参数达到35 kV/200 mA,波形前沿3 ms内可调,最大调制频率为1 kHz,调节精度在100 V以内。设计的控制方法也可应用于其他大功率微波源。     

大功率电子束轰击炉高压PWM电源的研制

介绍高压PWM-BUCK DC/DC变换器的工作原理,分析其工作特点,给出了应用于大功率轰击炉加速电源工程实践的技术路线.运行结果证明,高压PWM电源较之晶闸管移相调压控制的高压电源,具有输入电流谐波小、功率因素高及运行效率高等优点.     

一种数控高精度直流稳压电源的研制

设计一种基于AT89S51单片机的数字化通用直流稳压电源,采用12位D/A转换器DAC1208实现稳压电源的数字化控制,采用12位A/D变换器ICL7109和LCD实现输出电压的测量与显示.该系统电压调节范围0～20V,电压调节灵敏度为5mV,最大输出电流为2A,测试结果表明电压调整率为0.05%,负载调整率为0.051%,纹波小于1mV_(p-p).     

Long-pulse power-supply system for EAST neutral-beam injectors

The long-pulse power-supply system equipped for the 4 MW beam-power ion source is comprised of three units at ASIPP (Institute of Plasma Physics,Chinese Academy of Sciences):one for the neutralbeam test stand and two for the EAST neutral-beam injectors (NBI-1 and NBI-2,respectively).Each power supply system consists of two low voltage and high current DC power supplies for plasma generation of the ion source,and two high voltage and high current DC power supplies for the accelerator grid system.The operation range of the NB power supply is about 80 percent of the design value,which is the safe and stable operation range.At the neutral-beam test stand,a hydrogen ion beam with a beam pulse of 150 s,beam power of 1.5 MW and beam energy of 50 keV was achieved during the long-pulse testing experiments.The result shows that the power-supply system meets the requirements of the EAST-NBIs fully and lays a basis for achieving plasma heating.     

团簇尺度的瑞利散射测量中光电倍增管信号刻度与归一化处理

利用光电倍增管测量团簇的瑞利散射,信号幅度与团簇源背压有关,也与光源强度和光电倍增管工作电压有关.当团簇源背压变化范围较大时,散射信号幅度变化可能导致光电倍增管信号超出线性范围.为此,在不同的光源强度、不同的工作电压下对光电倍增管输出信号进行了刻度,得到了输出信号幅度随光源强度、工作电压之间的关系.用此关系.对不同条件下的实验数据进行归一化处理,得到了团簇散射因子随团簇源背压的关系曲线,与同类实验和理论结果相符.     

Numerical simulation and analysis of lithium plasma during low-pressure DC arc discharge

Alkali metal DC arc discharge has the characteristics of easy ionization, low power consumption, high plasma temperature and ionization degree, etc, which can be applied in aerospace vehicles in various ways. In this paper, we calculate the physical property parameters of lithium vapor, one of the major alkali metals, and analyze the discharge characteristics of lithium plasma with the magnetohydrodynamic (MHD) model. The discharge effects between constant current and voltage sources are also compared. It is shown that the lithium plasma of DC arc discharge has relatively high temperature and current density. The peak temperature can reach tens of thousands of K, and the current density reaches 6×10 ⁷ A⁻² . Under the same rated power, the plasma parameters of the constant voltage source discharge are much higher than those of the constant current source discharge, which can be used as the preferred discharge mode for aerospace applications.     

混合模式低噪声3 kV高压直流电源设计

高压直流电源是电离室等核辐射探测器的关键部件。针对需要3 kV左右高压的电离室,本文研制了0～3 kV连续可调的低噪声、高效率、小体积及高稳定性的高压直流电源。该高压直流电源系统采用线性与开关混合模式设计,兼顾了转换效率与低噪声。核心部分升压转换部分采用线性罗耶谐振电路与高频变压器实现,保证足够低的高压电源输出纹波。罗耶谐振电路的供电电源则由边沿时间控制型超低噪声开关稳压器LT1534提供,从而实现了混合模式高压直流电源的设计。高压直流电源输出部分采用二阶RC滤波电路进一步降低了输出电压的纹波。实测输出电压范围为0～3 kV,静态功耗为0.4 W,3 kV输出时纹波为16.55 mV,由此可知该电源可用于低噪声的核辐射探测器供电场合。     

辐射导致CMOS图像传感器暗电流随机电报信号

针对空间和核工业应用中辐射引起CMOS图像传感器产生暗电流随机电报信号（DC RTS）问题,对0.18 μm CMOS图像传感器进行不同能量质子、γ射线的辐照试验,辐照后对DC RTS特征参数进行分析。试验结果表明：由于位移损伤和电离总剂量效应产生的RTS缺陷不同,两种DC RTS在台阶、最大跳变幅度、平均时间等参数存在差异。相比于位移损伤产生的DC RTS,电离总剂量产生的DC RTS具有跳变幅度小、平均时间长的波动特点,导致此类DC RTS难以检测分析。像素积分期间传输栅电压会对电离总剂量诱发的DC RTS产生影响。上述工作为深入认识CMOS图像传感器DC RTS现象、探索相关抑制技术提供重要参考。     

Investigations of Tracking Phenomena in Silicone Rubber Using Moving Average Current Technique

In the present work, tracking phenomenon in Silicone rubber material has been studied under AC and DC voltage, with ammonium chloride as a contaminant. It is observed that the tracking is more severe under the DC voltages. The tracking time is less under negative DC compared to the positive DC voltage. The tracking mechanism is explained in detail. The leakage current during the tracking studies was as measured and the moving average technique was adopted to understand the trend in current flow. The leakage current magnitude is high with thermally aged specimens compared to the virgin specimen, irrespective of the type of applied voltage. It is realized that the tracking time and the leakage current magnitude shows an inverse relationship.     

Performance and modelling of 70kVdc power supply with solid-state crowbar

The experimental activities of tokamak research involve development of high power RF and microwave sources for fusion related heating and current drive applications. High power RF and microwave tubes like Klystron, Gyrotron and Tetrode are in general operated with high voltage DC power supplies. These HVDC power supplies of the order of 70 kVdc, must be equipped with necessary arc fault protection in addition to general over current and over voltage protection.The arc fault protection must act within few microseconds to prevent permanent damage to the RF tube, window, etc. When an arc fault is detected, output voltage of the DC power supply is short circuited using a crowbar device (generally Ignitron, Thyratron, thyristor, rail-gap, etc.) that operates in few microseconds. This diverts the fault current from the load to crowbar device, thereby protecting the load. This is necessary as conventional protection in the power supply input takes ～100 ms to switch-off. The crowbar device must be able to take the fault current till the circuit breaker placed at power supply input is switched off.The arc fault protection is tested for its effectiveness by “wire-burn” test. Full power short circuit of ～1.5 MW DC power supply puts enormous stress on the power supply, utility and the crowbar, therefore frequent wire-burn testing is to be avoided.This report presents simulation of wire-burn test using PSIM software. Optimization of the component values without conducting actual wire-burn test could be achieved.