基于DSP技术的长时间积分器

本文通过讨论积分器实现的形式和积分误差抑制的措施,介绍了一种先由模拟积分电路对输入信号进行交替积分,再用数字信号处理方式实现积分误差修正和积分结果拼接的长时间、低漂移积分器的设计方法,并给出了相关实验结果.     

EAST上低漂移差分积分器的研制

在核聚变实验中,积分器是还原磁探针微分信号的基本手段。传统的模拟积分器为单端输入积分器,无共模抑制能力。本文设计了一种差分积分器,采用与标准差分放大器类似的结构,实现了差分输入积分;进而分析了差分积分器对差分信号积分和对共模信号抑制的工作原理,设计了调节积分漂移的电路,有效抑制了差分积分器的积分漂移。测试结果表明,该差分积分器积分正确,积分漂移稳定且易于调节,在共模电压为1.5 V时,100 s积分漂移为80 μWb,共模抑制比高达125 dB,效果明显优于单端积分器。该差分积分器已成功应用于2012年EAST实验中单匝环信号的相对测量。     

可变积分时间常数的长时间积分器

采用可变积分时间常数和扣除积分漂移斜率相结合的方法,设计了一种新型长时间积分器。通过切换积分器积分电阻来改变积分时间常数,提高积分器的信噪比,防止积分输出饱和;利用DSP计算一段时间内积分器的积分漂移斜率,并利用该斜率对原始积分信号进行实时扣除,以达到减小积分漂移的目的。测试结果表明,该方案是一种有效消除积分漂移的长时间积分方法,并能消除改变积分时间常数后对积分漂移带来的不良影响,通过远程控制能方便地根据实验需要改变积分时间常数,且不再需要人工手动调节积分漂移,极大地提高了实验效率,适合于托卡马克装置放电实验中的电磁测量。     

HT-7积分器系统的定时触发模块设计与实现

本文设计一种积分器系统中的定时触发模块,详细介绍用单片机和晶体管设计定时触发模块的设计思路、硬件结构和软件设计等方面的内容.该模块为积分器系统提供精确的可词积分定时时间,且触发准确、驱动能力强.定时触发模块提高了积分器系统的可靠性和适用范围,满足HT-7实验要求.     

CLAM钢、EUROFER97钢与钨在HT-7托卡马克中辐照后的表面分析

两种低活化马氏体钢(CLAM、EUROFER97)以及钨被放入HT-7托卡马克的刮削层中,以研究托卡马克装置中高温等离子体与低活化马氏体钢和钨表面的相互作用。通过SEM装置观察,发现某些样品的表面形貌发生了很大变化。低活化马氏体钢的表面起泡比较密集,钨的表面起泡比较稀少,且直径较大。在一些样品的表面,还观察到了等离子体灰尘以及明显的被等离子体冲击后的痕迹。另外,XPS分析发现样品表面的某些元素成分也发生了变化,而且处在托卡马克装置中不同位置处的样品,其表面硅的含量呈现出明显的规律性。     

托卡马克HT-7U低温超导磁体的绝缘系统

主要介绍低温超导托卡马克HT-7U中磁体的绝缘结构,绝缘材料的特性,绝缘结构形成的工艺,绝缘层的电性能和力学性能等。     

HT-7超导托卡马克上γ辐射的初步研究

尝试了在HT-7托卡马克准稳态等离子体实验平台上，对伽马辐射能谱与通量进行测量与分析。实验中，测量得到了不同放电条件下的伽马辐射能谱和通量的时间演化过程，观测到了丰富的伽马辐射行为。针对欧姆加热、低杂波、离子回旋波、离子伯恩斯坦波、长脉冲等不同放电条件下的伽马辐射行为做了研究，结合其它相关诊断数据，给出了初步的分析结果。     

HT-7托卡马克实验装置上基于PLC控制的中性束诊断电源系统

文章介绍HT-7托卡马克实验装置上的中性束诊断电源系统的组成、结构，以及基于S7-300PLC的逻辑控制系统。实验表明，该系统操作简单，性能稳定可靠。     

低压低干度自然循环流量漂移和热虹吸现象的动态模拟

采用一维两相4方程漂移流模型编制程序,对5MW核供热堆模拟实验回路中发生的流量漂移现象进行数值模拟,同时分析热虹吸的机理,并对其进行动态模拟.结果表明,该程序可以对自然循环系统的静态不稳定性进行模拟,对流量漂移现象的模拟基本与实验相符.     

HL-2A中多路分时积分器的研制

中国环流器二号 A 装置(HL-2A)是我国第-个具有偏滤器位形的托卡马克装置,利用其极向偏滤器在高参数等离子体条件下开展与偏滤器位形运行有关的研究.直观的观测核放射过程中核脉冲信号随放射时间的强弱变化规律对于掌握受控核聚变有着重大的意义.我们为HL-2A装置研制的多路分时积分器具有自动削掉输入信号的负向反脉冲,积分时间0.2～1 ms五档可调,统一起始TTL触发脉冲,20 s自动定时工作,同时有十路信号积分的特点.     

长时间无零漂积分器中的单元积分电路

本文论述了应用在长时间无零漂积分器中的单元积分电路的原理与设计.该电路结合了零点补偿和基于斩波思想的分段积分两项技术,主要解决传统模拟积分器存在的积分零漂问题,使积分零漂减小到极低的水平,积分1000s绝对积分零漂典型值为16.7mV,同时也改善了由于积分泄漏引起的非线性误差.该电路的研制完成为进一步设计用于托卡马克装置上电磁测量的长时间积分器系统奠定了基础.     

Temperature of the Limiter Surface Measured by IR Camera in HT-7 Tokamak

Temperature measurement by IR （infrared） camera was performed oll HT-T tokamak. particularly during long pulse discharges, during which the temperature of the hot spots on the belt limiter exceeded 1000℃. The heat load on the surface of the movable limiter could be obtained through ANSYS with the temperature measured by IR-camera. This work could be important for the temperature measurement and heat load study on the first wall of EAST device.     

A digital long pulse integrator for EAST Tokamak

A digital integrator has been developed to be compatible with the long pulse plasma discharges on the Experimental Advanced Superconductor Tokamak (EAST), in which the induced signal is modulated by a chopper, and a field programmable gate array (FPGA) in the 16-bit digitizer is used to realize the digital integration in real time. After rectification and integration, the drift is almost linear and stable in controlled temperature, so a period of 50 s is used to determine the linear drift rate for drift compensation. The integration data can be directly transferred to the reflective memory (RFM) card, which is installed in the same PCI eXtensions for Instrumentation (PXI) chassis, so the data transmission can be also done in real time. The test results show that the real time data transmission rate is up to 10 kHz, the integration drift is typically less than 0.4 uVs/s and drift performance is a little worse in real long pulse discharge, which can be reduced further by using more precise data acquisition.     

Using Poloidal Flux as Feedback Control Signal for Injected Power of LHCD in Long Pulse Discharge on HT-7 Tokamak

Long pulse discharge is one of the important goals of HT-7 superconducting tokamak experiments. For ITER （International Thermonuclear Experimental Reactor） or a tokamak reactor, carrying out a steady operation is one of the main techniques. For long pulse discharges on HT-7 the poloidal flux is used as the feedback signal to control the injected power of LHCD （Low Hybrid Current Drive） system. Experimental results are presented.     

Design of flowing liquid lithium device for HT-7 tokamak

Lithium is a very attractive element due to its very low radiation power, strong H retention as well as strong O getter activity. Flowing liquid lithium (FLiLi) device, to be used as a plasma-facing limiters, has been designed and will be tested in HT-7 tokamak. It is mainly composed of distributor, guide plate, collector, and heater as well as cooling loop. The heater uses heater strip and cooling loop design, to control the temperature of lithium on the guide plate ranging from 200 °C to 400 °C. The distributor attached to feeding pipe, distributes liquid lithium (LiLi) flowing on the guide plate. The collector was designed to reclaim the superfluous LiLi and transport it out of device.The paper focuses on the design of flowing liquid lithium device. In addition to the process of design, thermal analysis has been carried out using finite element method (FEM) for optimizing the structure of heater and cooling loop and results of analysis are presented.     

Superconducting Busline Design for HT—7U Tokamak

Superconducting (SC) tokamak HT-7U has seven pairs of buslines connecting toroidal/Poloidal coils and the current leads,These SC buslines(SCBLs) share a common cryostat and are made of the calbe in conduit conductors(CICCs) arranged as a decoupling configuration.In order to reduce the heat loads conducted from the seven current leads with a capacity of 15kA during the magnets cooldown.the buslines with a much lower thermal conduction were employed in comparison with the current leads,and a special cooling loop was designed.     

Design of Amplifier Circuit for the HT-7 Tokamak Thomson Scattering System

Thomson scattering diagnostic is important for measuring electron temperature and density profiles. To improve the signal-to-noise ratio, a silicon avalanche photodiode （APD） with high quantum efficiency, high sensitivity, and high gain up to 100 was adopted to measure the Thomson scattering spectrum. A preamplifier, which has low noise, high bandwidth, and high sensitivity, was designed with suitable transimpedance. Using AD8367 as the post-amplifier, good performance of the APD readout electronics have been obtained. A discussion is presented on the performance of the amplifier using a laser diode to simulate the Thomson scattering light. The test results indicate that the designed circuit has a high amplifying factor and fast rising edge. So reduction of the integral gate of the CAMAC ADC converter can improve the signal-to-noise ratio.     

低通PID算法在HT-7密度控制系统中的应用研究

PID控制是反馈控制系统中最常用的控制方法,基于数字滤波技术设计的低通滤波PID算法通过滤掉误差信号中的噪音信号从而提高了算法的控制效果.介绍了HT-7密度控制系统结构,详细说明了该控制算法的原理及实现过程,该算法在HT-7密度控制系统中应用,得到了很好的控制效果.     

Preliminary Design of Control Network for HT-7U Tokamak Cryogenic System

In the course of the cryoplant modernization,a control network will be set up inorder to facilitate the control,the supervision,the centralized data acquisition and the alarmhandling of the cryogenic system for HT-7U tokamak.The paper introduces the preliminarydesign of control network based on the Controller Link Network for HT-7U tokamak cryogenic