光触发晶闸管光敏区结构的研究

本文对光触发晶闸管的两种不同光敏区结构进行了比较分析,对其中颇具吸引力的结构——有一薄n_E层的槽状光敏区结构,从理论和实验上进行了较为详细的研究,着重分析了不同参数条件下,n_B层厚度与触发灵敏度的关系.通过建立理论模型和进行数值模拟,得到了一些新的结果,表明对于一定的p_P基区参数和n_E层浓度,存在一最佳nE层厚度,在此厚度下,触发功率最小;而且采用此光敏区结构能得到触发灵敏度与dv/dt容量之间的较好折衷,?计算结果和实验吻合较好.     

SiC光触发晶闸管的发展与挑战

SiC光触发晶闸管不仅具备传统SiC晶闸管超高耐压、超大通流能力的特点,还在简化驱动电路、提高系统抗电磁干扰能力方面具备独有优势.概述了 SiC光触发晶闸管的发展历程,介绍了 SiC LTT紫外发光二极管(UV LED)触发、SiC LTT放大门极以及全光控SiC LTT等重要技术,讨论了 SiC LTT仍面临的低触发...     

大芯径移动光纤式光开关

激光点火装置是低电压启动设备,为了保障激光意外输出时的安全性,需要光开关作为激光点火系统的保险与解除保险装置。为此介绍一种适用于较高功率激光点火装置中的光开关。该光开关采用了移动光纤式结构,适用于较大芯径光纤。具有较低的插入损耗。     

应用设计中使用光直接触发晶闸管的优点

1997年eupec制造出了它的第一个具备完整保护功能的8kV光直接触发晶闸管。自那时起，eupec售出了10000多只不同尺寸和不同阻断电压的光直接触发晶闸管(LTT)。LTT由于阻断电压高的显著优点和易于实现光触发而被用于高压直流输电(HVDC)。LTT集成了多种保护功能，因此不再需要电触发晶闸管(ETT)的外部保护电路通常所需的昂贵而灵敏的电子元件。LTT用在需要晶闸管串联的高电压应用中。典型的例子有HVDC装置、静态VAR补偿器(SVC)、中压驱动中的变流器和软启动器以及各种脉冲功率应用。为了展示LTT的优异性能，首先需要关注的是系统成本和可靠性。     

大功率晶闸管开关的触发电路设计与研究

简述了半导体开关晶闸管的工作原理及触发条件。基于脉冲电源对大功率晶闸管的使用要求,对大功率晶闸管的触发电路进行了方案设计,重点分析了触发控制电路、光纤传输、触发信号发生电路的功能和工作过程,并在此基础上研制了一种晶闸管触发电路模块,进行了多次主回路触发放电实验,均能可靠触发,满足设计和使用要求。     

掺镱多模双包层光纤激光器弯曲选模研究

为了使大芯径多模双包层光纤激光器实现基模输出以抑制高功率双层光纤激光器中的非线性效应,采用将大芯径的多模双包层光纤适当弯曲进行选模使双包层光纤激光器获得单模激光输出的方法,进行了理论分析和实验验证,取得了大芯径多模双包层光纤内包层折射率、纤芯半径、光纤内传输信号光波长、光纤弯曲半径等因素对弯曲损耗及激光器输出光场模式影响的数据,并采用国产掺镱多模双包层光纤进行了弯曲选模实验,实现了多模光纤激光器的单模输出.结果表明,激光器最大输出功率达9W,斜率效率达17.3%,输出为基模.这一结果对大芯径多模双包层光纤激光器的选模是有帮助的.     

基于应变的多模光纤可调谐光纤滤波器设计

可调谐光纤滤波器技术是波分复用系统的关键技术之一,对于发展全光通信网络和光纤传感具有极其重要的意义。提出了一种基于大芯径的多模光纤可调谐带阻滤波器,其制作方法是将包层/纤芯直径为125/105μm的特种多模光纤通过单模光纤接入光纤系统,实现单模-多模-单模(SMS)光纤结构,并使一端单模光纤与多模光纤熔接,另一端只是共轴对接而不焊接。在多模干涉原理的基础上,利用该结构对应变的敏感性实现可调谐光滤波。该可调谐滤波器的调制和解调借助于放大自发辐射(ASE)宽谱光源和光谱分析仪(OSA)实现。详细给出了该滤波器的理论仿真分析,并实验证实了该方案的有效性。     

晶闸管触发模块KM—18—3的应用

ＫＭ－１８－３是晶闸管移相触发专用器件。文章描述了ＫＭ－１８－３的基本原理和引脚功能，列出了器件的基本参数，并着重介绍了该器件的实际应用。     

串连晶闸管阀触发方式分析与研究

晶闸管耐压较陈，中高压领域所用晶闸管阀（TCR、TSC等）均需多支晶闸管串连才能满足耐压需要。本文分析了传统的串连晶闸管的触发特点，并提出了一种新颖的晶闸管触发方式光电＋电磁触发。在山东泰开电力电子有限公司生产的高压TSC晶闸管阀上进行了试验验证。试验结果证明，采用光电＋电磁被发方式，晶阐管触发一致性好，触发电流大，抗电磁干扰能力强，具有较好的推广价值。     

一种改进的晶闸管触发电路研究

晶闸管触发电路的作用是产生符合要求的门极触发脉冲,保证晶闸管在需要的时刻由阻断变为导通。为了在寒冷条件下对软起动器的晶闸管可靠触发,针对传统触发电路触发脉冲前端无强脉冲,在传统的触发电路基础上进行了改进。通过改进,使触发脉冲的电流前沿有了强触发脉冲。实验证明,该触发电路满足了实际的需要。     

High-power dual amplifying gate light triggered thyristors

The feasibility of directly light triggering a high power phase control thyristor is investigated. Work is described on an optically triggered gated 53-mm diameter 2600-V 1000-A thyristor which is similar to an electrically gated production version. Test results describing the response of this thyristor to various optical signals are presented. Our work has shown that this cell can be directly triggered by light at an equivalent gate current which is a factor of three below its present dynamic gate requirements and still largely retain all its blocking and dynamic characteristics. This improvement is obtained by the use of a second very sensitive amplifying gate stage which is responsive to light. All wafer processing of the light sensitive thyristor was carried out on standard production lines. Tests made on static dV/dt, di/dt, blocking voltage, and leakage current on light sensitive devices all closely match parameters of the standard electrically fired equivalent cell.     

Progress in light activated power thyristors

Light activated power thyristors would have considerable advantages in intermediate- and high-voltage circuits, as power and trigger circuits could be electrically separated by use of glass fiber cables. Besides high-voltage capability, such devices must have turn-on delay times, dv/dt capabilities, and di/dt stabilities which are comparable to conventionally fired thyristors. The necessary trigger power, however, has to be kept low enough to enable firing with GaAs light emitters, which are available now or will be in the near future. The dv/dt sensitivity is an essential limitation for the reduction of the minimum necessary trigger power. Optimizing of the thyristor emitter shunts results in an already acceptable compromise, but much better results can be obtained by a gate structure which actively compensates dv/dt fault triggering. Our test devices show good turn-on behavior. A short survey on different GaAs-light sources and the coupling problem is given.     

The forward characteristics of thyristors

A theory on the forward V-I characteristics of P⁺-P-N-P-N⁺thyristors is proposed. Taking the minority carrier lifetime in the base region into account, the effects of the device structures on the forward characteristics are discussed on the following three cases: 1) low-level operation, 2) middle-level operation, and 3) high-level operation. At middle-level operation, the term that is independent of current and, at high-level operation, the √I dependency, appears in the forward characteristics of the thyristors. The general theory is illustrated by reference to experimental results on silicon-controlled rectifiers.     

High-energy pulse-switching characteristics of thyristors

Experiments were conducted to study the high energy, high di/dt pulse-switching characteristics of silicon controlled rectifiers (SCRs) with and without the amplifying gate. High di/dt, high-energy single-shot experiments were first done. Devices without the amplifying gate performed much better than the devices with the amplifying gate. A physical model is presented to describe the role of the amplifying gate in the turn-on process, thereby explaining the differences in the switching characteristics. The turn-on area for the failure of the devices was theoretically estimated and correlated with observations. This allowed calculation of the current density required for failure. Since the failure of these devices under high di/dt conditions was thermal in nature, a simulation using a finite-element method was performed to estimate the temperature rise in the devices. The results from this simulation showed that the temperature rise was significantly higher in the devices with the amplifying gate than in the devices without the amplifying gate. From these results, the safe operating frequencies for all the devices under high di/dt conditions was estimated. These estimates were confirmed by experimentally stressing the devices under high di/dt repetitive operation     

Switching characteristics of electron-irradiated MOS-controlled thyristors

MOS-controlled thyristors (MCTs) were designed and fabricated. The effect of electron irradiation on static and dynamic characteristics has been studied. Electron irradiation was found to substantially reduce the MCT turn-off time. An increase in the controlled current density was observed.     

The characteristics of pump light in side-coupled cladding-pumped fibers

The propagation and absorption characteristics of pump light in the side-coupled cladding-pumped active fiber were investigated. A model taking both the absorbing and coupling coefficients into account was established. It is revealed that the absorbing effect of the active fiber enhance the pump-light coupling from the passive fiber to the active fiber, while the coupling effect reduce the absorbing process compared to the common double-cladding fiber. The study also considers the effect of the coupling coefficient ratio. It is found that higher effective absorption coefficient requires bigger absorption coefficient and smaller coupling coefficient ratio.     

Comparison of light triggered and electrically triggered thyristor turn-on

As part of an EPRI (Electric Power Research Institute) funded research program on a directly light triggered (LT) thyristor for HV dc application, an existing 53-mm 2600-V 1000-A electrically fired device was suitably modified to be turned on with an incident photo-pulse of 20 nJ, the basic problem being the retention of a 2000 V/µsdV/dtcapability. The price paid for high sensitivity and highdV/dtcapability was found to be a device inherently more susceptible todV/dtfailure. In the efforts to cope with this problem a number of computer-type models were developed to assist in predicting turn-on in both electrically and light fired devices with one or more amplifying stages. At the same time, devices were fabricated which could be either light or electrically fired. Both the model and experiment point to faster turn-on of the light fired device and an increased requirement for careful design.     

Analysis of n-channel MOS-controlled thyristors

The turn-off of the n-channel MOS-controlled thyristor (NMCT) is analyzed using two-dimensional simulation. A lateral NMOS-controlled thyristor structure, LNMCT, suitable for HVIC application is also proposed. It is found that the operation of a parasitic lateral n-p-n transistor in NMCT-type structures degrades the forward voltage drop and the turn-off capability and hence should be suppressed. The maximum controllable current in the NMCT is not only a function of internal parameters, but also depends on external supply voltage. This indicates that snubberless operation of an MCT-type device is not feasible. The advantages and disadvantages of the NMCT are compared with those of conventional MCT structures. The LNMCT turn-off speed is limited by the large amount of holes existing in the substrate, resulting in a turn-off waveform similar to that of an LIGBT     

Switching characteristics of 45-A double-interdigitated GTO thyristors

This work presents the turn-off, turn-on and high-frequency switching characteristics of 45-A 1500-V double-interdigitated GTO switches. The devices possess the highest value of the peak interruptable anode current ever reported in the open literature for 4 × 4 mm area thyristors packed into TO-220 cases. The dynamic evaluation of devices was performed under resistive-inductive load conditions, i.e., close to those encountered in practical circuits employing GTO thyristors. The performed investigations have shown that the novel type of GTOs exhibit the best overall switching characteristics ever presented for this class of GTO switches (identical area and case). The devices performed well under high current and voltage conditions. Even the worst recorded data at higher turn-on and turn-off gains show that the developed GTOs behave as fast commutation devices consuming low input (gate) energy. It was demonstrated that fast turn-off is by no means incompatible with excellent turn-on sensitivity. A remarkable feature of devices consists in a built-in self-protection capability against electrothermal failure during gated turn-off. This unique feature enables the GTOs both to switch large amounts of load current and to safely operate at high commutation frequencies (hundred of kHz) under heavy load conditions.     

光子晶体光纤的色散特性分析

为了探讨靠近纤芯区域的第1层、第2层和第3层空气孔的直径对光子晶体光纤色散特性的影响,采用有限元法进行了理论分析.结果表明,适当调节第1层、第2层和第3层空气孔的直径,可以使零色散点在1100nm-1800nm之间的任何位置上移动.还可以设计在1270nm～1800nm较宽的波长范围内接近零色散的色散平坦光子晶体光纤.这一结果对光子晶体光纤的设计具有重要的作用.