专业英语
课程论文
院系名称：电气工程学院专业班级: 电气F1103班学生姓名：学号：
附件： 1.中文论文；2.外文论文。
绝缘栅双极晶体管
亚历克斯问黄1
(1.弗吉尼亚理工学院暨州立大学，美国弗吉尼亚州)
摘要：通过对门极可关断晶闸管的产生背景，物理结构及其基本的工作原理的进一步探讨和研究，可以得出门极可关断晶闸管具有在门极施加负的脉冲电流使其关断的性能，并证明它是全控型器件。
关键词：门极可关断晶闸管；工作原理；单位关断增益；动态特性；静态特性；
1 引言
在20世纪50年代发明的可控硅整流器（SCR）【1】是第一个被投入使用的功率半导体开关。SCR 是一个闭锁装置，只有ON和OFF两个稳定状态。通过很小的门极触发电流使其从OFF状态转换成ON 状态的正反馈过程来启动装置。由于电子和空穴的注入，提供了强有力地电导调制，使得SCR能很好地权衡正向压降和阻断电压。另外从制造的角度看，SCR的结构很简单，因为它的门极可以被放置在一个小的区域，因此单一的SCR可以很容易地被扩展以增加设备的电流能力而没有太多的处理问题。然而可控硅不能通过门极控制其关断。
由于SCR的关断可控性的限制，门极可关断晶闸管（GTO）【2】后来得到发展。正如它的名称所表示的，GTO是一种通过门极控制其关断的装置。它的基本结构与SCR非常相似。然而在GTO中许多门极被放置在阴极的周围，这样在关断期间，闩锁机制可以通过门极控制来解除。因此GTO是全控型器件。到今天为止，GTO具有最高的额定功率和在阻断电压及任何全控开关导通损耗的最佳折衷。然而其动态性能很差，GTO在导通和关断时不快。它缺乏FBSOA且RBSOA较差，因此它需要缓冲器控制关断转换期间dv/dt的和导通转变期间的di/dt。
GTO晶闸管是全控型的功率半导体开关之一。它的功率应用范围从早期的低功率（低于100W）到数百兆瓦的高功率。一个最先进的GTO可在硅片上制成6英寸大小。其电流高达6.0KA，电压高达6.0KV.【3】该等级高于其他全控设备等级。
GTO的静态参数很好：具有传导低损耗，高阻断电压且由于集成化成本很低。但其动态性能很差。其关断和开通运行期间分别对dv/dt和di/dt 缓冲的要求及最小量的开通和关断次数使得GTO 难以使用。要提高GTO的动态性能，同时保持其良好的静态性能，很好地了解GTO的结构是必要的。在本章节我们将总结和讨论GTO的基本工作原理，其优点和缺点及决定其性能的结构。然后引入一个新的门极驱动概念，即单位关断增益。并分析和讨论这种新的驱动方法的优点。最后将总结已知的这种特殊驱动技术的使用方法。
2正文
2.1GTO的正向传导
图1.75a为一个典型的高功率GTO的微型结构和掺杂分布。图1.75b显示了两个晶体管GTO模型图。图1.75c是一幅4英寸的GTO图片。这是一个三端四层的PNPN结构。外部的p+层上的电极成为阳极，其电流通常流入设备。外部n+层上的电极称为阴极，内部的p层上的电极称为门极，被用作控制。
图1.75：（a）GTO元的结构和它的掺杂分布（b）晶闸管的双晶体管
模型 (c)4英寸GTO的外形
通过图1.75b所示的等效电路模型来理解GTO 的工作原理。PNP晶体管代表GTO的最高三层，而NPN晶体管代表GTO底部的三层。由于n层作为pnp 型的基极，npn型的集电极和内部的p层作为npn型的基极，pnp型的集电极使得两个晶体管交叉耦合。这种结构具有两个稳定状态：ON和OFF，这是由门控制。当电流从门-阴极注入GTO时，npn结构导通，它的集电极电流通过J1结流入GTO的阳极。由于J1是pnp结构的发射结，PNP型的集电极电流是npn的基极电流。因此，两个晶体管提供基极电流给对方，形成正反馈。直到他们达到自我维持的状态，俗称闭锁。高层次的少数载流子的注入可在锁定状态下从阳极到阴极，使得所有三个pn 结正向偏置。因此，从阳极到阴极存在高导电性，使高电流从阳极流动到阴极。图1.76所示为其导通过程。
图1.76 GTO导通及电流维持过程
在芯片级，J3结导通导致电子注入p基区。这些电子从p基极扩散，大多由反向偏置连接点J2结收集。为保持电流的连续性，结点J1处将供给电流，通过将空穴注入n区域。这些空穴的一部分，将扩散的n-区，并被J2结收集，导致在J3结流入更多的电子。当两个晶体管工作在足够的电流增益，一个正反馈机制是足以导致闭锁。
让npn和pnp的基极电流增益分别为apnp和anpn。通常情况，αpnp低于anpn。因为pnp是宽基结构。电流流进GTO如图1.77所示。在J2结，电流由阴极侧注入是npnIK；由阳极侧注入是pnpIA。漏电流为IL。
图1.77 驱动电流流进GTO图
晶闸管结构可以维持其本身的阳极电流，只要两个晶体管共同的基极电流增益（αpnp + αnpn）之和趋近一致。对GTO ，αnpn设计的低，通常是为IG ，以确保其门极关断能力。这将在稍后讨论。与此自持能力，GTO的栅极并不需要提供很多电流，不需要非常接近其阴极不像在双极结型晶体（BJT）设计是必要的。一个典型的GTO元，示于图1.75.其维数是100?150 微米宽。这相比微米和/或亚微米工艺被用于现代化的MOSFET和绝缘栅双极型晶体管（IGBT）是非常大的。大细胞大小的设计是符合成本效益的，并且使得可以制造大单芯片器件，以提高他们目前的能力。一个国家的最先进的GTO模具的直径是6英寸大。其关断电流能力可达6.0KV【4】。图1.75显示的巨大的GTO是由ABB制造的。显示的GTO是一个4英寸硅晶片由成千上万的如图1.75所示的GTO元和所谓的压装或曲棍球冰球包中打包组成。
GTO的大细胞结构在开通过渡期间带来了电流扩展问题。当注入门极电流，首先发生在导通的门极附近。导通区域扩散在阴极的其余部分。这可以由称为扩展速度【5】的驱动速度定性。实验测量【6】出典型的扩展速度是5000厘米/秒。该速度也依赖于对GTO的设计参数，注入门极的导通电流及diG/dt。
由于这个扩展的速度，整个GTO元导通需要一段时间。为了避免过分强调首先开启的单元格的部分，阳极电流的增加率应加以限制。给GTO设定最大导通di / dt的限制。
GTO的主要优点是它的低正向压降和高电压阻断能力。这些可以被理解为两端的少数载流子注入机制的主要好处。对于高电压的GTO，厚且轻掺杂n基极是必要的（见图1.75）。正向电压在这种情况下，主要取决于由电阻电压降的电压阻挡区少数载流子发挥了重要作用。
图1.78（a）GTO和（b）IGBT电压阻挡区导通状态的少数载流子分布图1.78a所示是GTO中n-区的少数载流子的分
布。图1.78b是一个IGBT的情况。对于设计相同
的阻断电压，它们的n区应该有类似厚度和掺杂。
由于只有一个晶体管的IGBT结构中，少数载流子
的只能从一侧注入，因此，比对GTO在n-区的电导
率调制弱。在GTO，因为有两个晶体管，少数载流
子被注入两端，使得整个区域中的更均匀的等离
子体分布。对于4.5千伏状态的的艺术GTO，其正
向压降为50 A/cm2的电流密度可低至2.0 V[7]如
果一个常数栅极电流注入呈现。图1.79显示了一
个国家的最先进的GTO的通态特性由ABB生产的。
正向电压降是在2000A只有大约1.5 V，4.5千伏GTO。此结果是典型的低导通损耗GTO。
2.2 GTO元之间的非均匀关断过程
对于高功率GTO，实验获得的关断瞬间功
率，可以承受远远低于动态雪崩击穿所设置的值
如式（1.21）。所以从GTO需要的dV / dt缓冲来
塑造其关断的I-V的轨迹，如图1.72示，可以应
用降低最大平均瞬时功率的外部电路。非均匀的
电流分布或电流丝[在GTO元中受到关断运行的限
制。电流丝在关断开始时形成，这是由存储时间
的差异，或在关断时的电压和电流都高的动态雪
崩所造成的结果。
参考文献
1. S.K. Gandhi, Semiconductor Power Devices, Wiley,
New York, 1977.
2. E.D. Wolley, Gate Turn-Off in P-N-P-N devices,
IEEE Trans. Electron Devices, ED-13, 590–597, 1966.
3. Mitsubishi GTO FG6000AU-120D data sheet.
4. B.J. Baliga, Power Semiconductor Devices, PWS Publishing Company, Boston, 1996.
5. W.H. Dodson and R.L. Longini, Probed determination
of turn-on spread of large area thyristors,
IEEE Trans. Electron Devices, ED-13, 478–484, 1966.
6. H.J. Ruhl, Spreading velocity of the active area
boundary in a thyristor, IEEE Trans. Electron Devices, ED-17, 672–680,1970.
Gate Turn-Off Thyristors
Alex Q. Huang
(1. Virginia Polytechnic Institute and State University，America Virginia)
Abstract-Through the background of the gate turn-off (GTO) thyristor, the physical structure and basic working principle of further exploration and research, it can be concluded that a GTO is a device that can be turned off through its gate injecting a gate negative pulse current. It is proved to be a full-controlled device.
Key words:Gate Turn-Off Thyristor;Unity-gain turn-off; Basic working; Dynamic characteristic; Static performance 门极可关断晶闸管单位关断增益基本工作原理动态特性静态特性
I.I NTRODUCTION
The first power semiconductor switch that was put in use was the silicon controllable rectifier (SCR) [1] invented in 1950s. The SCR is a latch-up device with only two stable states: ON and OFF. It does not have FBSOA. It can be switched from OFF to ON by issuing a command in the form of a small gatetriggering current. This will initiate a positive-feedback process that will eventually turn the device on.. The SCR has a good trade-off between its forward voltage drop and blocking voltage because of the strong conductivity modulation provided by the injections of both electrons and holes. Moreover, the structure of an SCR is very simple from a manufacturing point of view because its gate can be placed at one small region. The size of a single SCR can therefore be easily expanded to increase the current capability of the device without too many processing problems. There are 8.0 kA/10.0 kV SCRs commercially available that use a 6-in. silicon wafer for current conduction. However, SCRs cannot be turned off through their gate controls.
Because of the limitation of the turn-off controllability of the SCR, the gate turn-off (GTO) thyristor [2] was subsequently developed. As its name denotes, a GTO is a device that can be turned off through its gate control. Its basic structure is very similar to that of an SCR. However, many gate fingers are placed in the GTO surrounding its cathode. During a turn-off operation, the latch-up mechanism can be broken through the gate control.
A GTO is thus a device with full gate control and similar high current–voltage rating of an SCR. To date, the GTO has the highest power rating and the best trade-off between the blocking voltage and the conduction loss of any fully controllable switch. However, the dynamic performance of GTOs is poor. A GTO is slow in both turn-on and turn-off. It lacks FBSOA and has poor RBSOA so it requires snubbers to control dV/dt during the turn-off transition and dI/dt during turn-on transition.
The GTO thyristor was one of the very first power semiconductor switches with full gate control. It has served many power applications ranging from low power (below 100 W) in its early years to high power up to hundreds of megawatts. A state-of-the-art GTO can be fabricated on a silicon wafer as big as 6 in. and can be rated up to 6.0 kA and 6.0 kV [3]. This rating is much higher than the ratings of any other fully controllable devices.
The GTO static parameters are excellent: low conduction loss due to its double-sided minority carrier injection, high blocking voltage, and low cost due to its fabrication on a large single wafer. However, its dynamic performance is poor. The requirements of a dV/dt snubber during turn-off operation, a dI/dt snubber during turn-on operation, and minimum on and off times make the GTO difficult to use. To improve the dynamic performance of the GTO while keeping its good static performance, a better understanding of the mechanism of the GTO is necessary. In this section, the basic operating principle of the GTO, its advantages and disadvantages, and the mechanism that determines its performance are summarized and discussed. A new gate-driving concept, namely, unity-gain turn-off, is then introduced. The advantages of this special driving method are analyzed and discussed. Finally, all known approaches that make use of this special driving technique are summarized.
II.GTO F ORWARD C ONDUCTION
Figure 1.75a illustrates the cell structure and
the doping profile of a typical high power GTO. Figure 1.75b shows the two-transistor GTO model; and Fig. 1.75c is a photograph of a 4-in. GTO along with its gate lead. The structure is a three-terminal, four-layer pnpn structure with a lightly doped n?voltage-blocking layer in the center [4]. The electrode on the external p+ layer is called the anode where the current normally flows into the device. The electrode on the external n+ layer is called the cathode from where the current normally flows out. The electrode on the internal p layer (p-base) is called the gate, which is used for control.
FIGURE 1.75 (a) GTO cell structure and its doping profile;
(b) The two-transistor GTO model; (c) a photograph of a 4-in.
GTO along with its gate lead.
The operating principle of a GTO can be understood through its equivalent circuit model shown in Fig. 1.75b. The pnp transistor represents the top three layers of the GTO, whereas the npn transistor represents the bottom three layers of the GTO. Since the n? layer serves as the base of the pnp and the collector of the npn, and the internal p layer serves as the base of the npn and the collector of the pnp, the two transistors are cross-coupled. This structure has two stable states: ON and OFF, which are determined by its gate control. When a current is injected into the GTO from its gate to its cathode, the npn structure is turned on and its collector current flows from the anode of the GTO through J1 junction. Since J1 is the emitter junction of the pnp structure, the collector current of the pnp is then the base current of the npn. The two transistors therefore provide base currents to each other, forming a positive feedback among them until they reach a self-sustaining state commonly known as latch-up or latched. Under the latched condition, high-level minority carrier injections are available from the anode to the cathode, with all three pn junctions forward-biased. A high conductivity therefore exists from anode to cathode, allowing high current to flow from the anode to the cathode. Figure 1.76 illustrates this
turn on process.
FIGURE 1.76 Turn-on and current-sustaining process in a GTO.
At the silicon level, the turn-on of junction J3 results in the injection of electrons into the p-base region. These electrons diffuse across the p-base and are mostly collected by the reverse biased junction J2. To maintain the continuity of the current, junction J1 will supply a current by injecting holes into the n? region. Part of these holes will diffuse across the n? region and are collected by junction J2, resulting in more electron injection from junction J3. When both transistors operate at sufficient current gain, a positive feedback mechanism is sufficient to result in latch-up.
Let the common base current gain of the pnp and npn be αpnp and αnpn, respectively. Normally, αpnpP is lower than αnpn since the pnp is a wide-base structure. The current flow inside a GTO is illustrated in Fig. 1.77. At junction J2, the current due to cathode side injection is αnpnIK; the current due to anode side injection is αpnpIA; and the leakage current is IL. According to Kirchhoff’s law
.
FIGURE 1.77 Current flow in a GTO with gate drive current.
This equation shows that the thyristor structure can sustain its anode current by itself
once the sum of the common base current gain (αpnp + αnpn) of both transistors is approaching unity. For a GTO, αnpn is designed low and is normally depending on IG to ensure its gate turn-off capability. This will be discussed later. With this self-sustaining capability, the gate of a GTO does not need to supply a lot of current and does not need to be very close to its cathode as is necessary in a bipolar junction transistor (BJT) design. The dimension of a typical GTO cell shown in Fig. 1.75 is 100 to 150 μm wide. This is very large compared with the micron and/or even submicron process used for modern MOSFETs and insulated gate bipolar transistors (IGBTs). The large cell size design is cost-effective and makes it possible to fabricate large single-die devices to boost their current capability. A state-of-the-art GTO die is as large as 6-in. in diameter with a turn-off current capability of up to 6.0 kA [3]. Figure 1.75c shows a large GTO fabricated by ABB. The GTO shown is fabricated on a 4-in. silicon wafer consisting of thousands of cells like the one shown in Fig. 1.75 and packaged in a so-called press-pack or hockey-puck package.
The large cell structure in the GTO introduces a current spreading problem during the turn-on
transition of a GTO. When a gate current is injected, the turn-on occurs first in the vicinity of the gate contact. The conduction area then spreads across the rest of the cathode area. This can be characterized by a propagation velocity called the spreading velocity [5]. Experimental measurements [6] have shown a typical spreading velocity of 5000 cm/s. This velocity also depends on the GTO design parameters, the gate turn-on injection current, and its dIG/dt.
Because of this spreading velocity, it takes time for the whole GTO cell to turn on. To avoid overstressing the part of the cell that is turned on first, the increasing rate of the anode current should be limited. This sets the maximum turn-on dI/dt limitation for a GTO.
The major advantages of the GTO are its low forward voltage drop and high-voltage blocking capability. These can be understood as the major benefits of its double-side minority carrier injection mechanism. For high-voltage GTO, a thick and lightly doped n-base is needed (see Fig. 1.75). The forward voltage drop in this case is mainly determined by the resistive voltage drop in the voltage-blocking region where minority carriers
play an important role.
FIGURE 1.78 On-state minority carrier distribution in the voltage blocking region for (a) GTO and (b) IGBTi.
Figure 1.78a shows the minority carrier distribution in the n ? region of a GTO and Fig. 1.78b shows the case of an IGBT (see Section 1.9). For the same blocking voltage design, their n ? regions should have similar thickness and doping. Since there is only one transistor in the IGBT structure, minority carriers can only be injected from one side; therefore, the conductivity modulation in the n ? region is weaker than that of the GTO. In the GTO, since there are two transistors, minority carriers can be injected from both ends, making a more uniform plasma distribution in the whole area. For a 4.5-kV state-of-the-art GTO, its forward voltage drop at a current density of 50 A/cm2 can be as low as 2.0 V [7] if a constant gate current injection presents. Figure 1.79 shows the on-state characteristics of a state-of-the-art GTO manufactured by ABB . The forward voltage drop at 2000 A is only about 1.5 V for this 4.5-kV GTO. This result is typical of a low conduction loss GTO.
Ⅲ Non-Uniform Turn-Off Process among GTO Cells
For a high-power GTO, the experimentally
obtained instant turn-off power it can withstand is far below the value set by the dynamic avalanche breakdown shown in Eq. (1.21). So a GTO needs help from a dV/dt snubber to shape its turn-off I –V trajectory, as is shown in Fig. 1.72, and to lower the maximum average instant power the external circuit can apply. Non-uniform current distribution or current filament among GTO cells during the turn-off operation accounts for this limitation. The current filament can be formed at the beginning of the turn-off due to differences in storage times or caused by the onset of the
dynamic avalanche during the turn-off when the voltage and current are both high.
R EFERENCES
1. S.K. Gandhi, Semiconductor Power Devices, Wiley, New York, 1977.
2. E.D. Wolley, Gate Turn-Off in P-N-P-N devices, IEEE Trans. Electron Devices, ED-13, 590–597, 1966.
3. Mitsubishi GTO FG6000AU-120D data sheet.
4. B.J. Baliga, Power Semiconductor Devices, PWS Publishing Company, Boston, 1996.
5. W.H. Dodson and R.L. Longini, Probed determination of turn-on spread of large area thyristors,
IEEE Trans. Electron Devices, ED-13, 478–484, 1966.
6. H.J. Ruhl, Spreading velocity of the active area boundary in a thyristor, IEEE Trans. Electron Devices, ED-17, 672–680, 1970.
Page1 Electrical Energy Transmission（电能输送） From reference 1 Growing populations and industrializing countries create huge needs for electrical energy. Unfortunately, electricity is not always used in the same place that it is produced, meaning long-distance transmission lines and distribution systems are necessary. But transmitting electricity over distance and via networks involves energy loss. So, with growing demand comes the need to minimize this loss to achieve two main goals: reduce resource consumption while delivering more power to users. Reducing consumption can be done in at least two ways: deliver electrical energy more efficiently and change consumer habits. Transmission and distribution of electrical energy require cables and power transformers, which create three types of energy loss: the Joule effect, where energy is lost as heat in the conductor (a copper wire, for example); magnetic losses, where energy dissipates into a magnetic field; the dielectric effect, where energy is absorbed in the insulating material. The Joule effect in transmission cables accounts for losses of about 2.5 % while the losses in transformers range between 1 % and 2 % (depending on the type and ratings of the transformer). So, saving just 1 % on the electrical energy produced by a power plant of 1 000 megawatts means transmitting 10 MW more to consumers, which is far from negligible: with the same energy we can supply 1 000 - 2 000 more homes. Changing consumer habits involves awareness-raising programmers, often undertaken by governments or activist groups. Simple things, such as turning off lights in unoccupied rooms, or switching off the television at night (not just putting it into standby mode), or setting tasks such as laundry for non-peak hours are but a few examples among the myriad of possibilities. On the energy production side, building more efficient transmission and
自动控制论文 作者洪劲松 专业电气工程及其自动化 学号120301628 指导教师赵国新
Automatic control is when no one is directly involved in the case, the use of additional equipment or control device, the machine, device, or a working state of the control object or parameters (charged) automatically according to the predetermined rules. The traditional industrial production process using dynamic control technology, can effectively improve the quality of the products and the enterprise economic benefit. In today's rapid development of science and technology, automatic control technology in the field of industrial and agricultural production, national defense and science and technology, has a very important role. In a short span of one hundred years, the development of automatic control theory has been surprising, has a huge impact on human society. Automatic control theory is the study of automatic control common law science and technology. It is both an ancient and has become a mature discipline, another door is developing, the strong vitality of the emerging disciplines. From 1868 maxwell J.C.M axwell low order system stability criterion is put forward to date more than one hundred years, the development of automatic control theory can be divided into four main stages: the first stage: the classical control theory (or) classical control theory of the formation, development and maturity; The second stage: the rise of modern control theory and development; The third stage: big system control the rise and development stage; The fourth stage: intelligent control stage of development. The basic characteristics of the first stage of the classical control theory is mainly used for linear time-invariant systems research, namely for describing the system of linear differential equation with constant coefficients of analysis and synthesis; It is used only for single input and single output feedback control system; Only discuss the relationship between the system input and output, and ignore the internal state of the system, is a method of external description of the system. The basic method used: root locus method, frequency method, PID regulator (frequency domain). Control theory in the early stage of development, the automatic adjustment principle is based on the feedback theory, mainly used in industrial control. Feedback theory for feedback control. Feedback control is one of the most basic is the most important control mode, after the introduction of feedback signal, system response to come from the external and internal interference become very dull, so as to improve the anti-interference ability and the control precision of the system. Feedback effects, meanwhile, brings the problem of system stability, which was once the system stability problem in people inspired people to conduct the thorough research to the feedback control system in the enthusiasm, promote the development of the theory of automatic control and improvement. So in a sense, the classical feedback control theory is accompanied by the emergence and development of control technology and gradually improve and mature. During the second world war, in order to design and manufacture of aircraft and Marine autopilot, artillery positioning system, radar tracking system based on feedback principle of military equipment, to further promote and perfect the development of automatic control theory. In 1868, maxwell (J.C.M axwell) lower order algebraic criterion of the stability of the system are put forward. In 1875 and 1896, mathematicians rous (Routh) and hull weitz (Hurwitz) respectively independently the stability criterion of high order system was put forward, namely the Routh Hurwitz criterion. During the second world war (1938-1945), Nyquist (H.N yquist) in 1948, proposed the theory of frequency
High-speed milling High-speed machining is an advanced manufacturing technology, different from the traditional processing methods. The spindle speed, cutting feed rate, cutting a small amount of units within the time of removal of material has increased three to six times. With high efficiency, high precision and high quality surface as the basic characteristics of the automobile industry, aerospace, mold manufacturing and instrumentation industry, such as access to a wide range of applications, has made significant economic benefits, is the contemporary importance of advanced manufacturing technology. For a long time, people die on the processing has been using a grinding or milling EDM (EDM) processing, grinding, polishing methods. Although the high hardness of the EDM machine parts, but the lower the productivity of its application is limited. With the development of high-speed processing technology, used to replace high-speed cutting, grinding and polishing process to die processing has become possible. To shorten the processing cycle, processing and reliable quality assurance, lower processing costs. 1 One of the advantages of high-speed machining High-speed machining as a die-efficient manufacturing, high-quality, low power consumption in an advanced manufacturing technology. In conventional machining in a series of problems has plagued by high-speed machining of the application have been resolved. 1.1 Increase productivity High-speed cutting of the spindle speed, feed rate compared withtraditional machining, in the nature of the leap, the metal removal rate increased 30 percent to 40 percent, cutting force reduced by 30 percent, the cutting tool life increased by 70% . Hardened parts can be processed, a fixture in many parts to be completed rough, semi-finishing and fine, and all other processes, the complex can reach parts of the surface quality requirements, thus increasing the processing productivity and competitiveness of products in the market. 1.2 Improve processing accuracy and surface quality High-speed machines generally have high rigidity and precision, and other characteristics, processing, cutting the depth of small, fast and feed, cutting force low, the workpiece to reduce heat distortion, and high precision machining, surface roughness small. Milling will be no high-speed processing and milling marks the surface so that the parts greatly enhance the quality of the surface. Processing Aluminum when up Ra0.40.6um, pieces of steel processing at up to Ra0.2 ~ 0.4um.
微电子学专业词汇 A be absorb in 集中精力做某事 access control list 访问控制表 active attack 主动攻击 activeX control ActiveX控件 advanced encryption standard AES,高级加密标准 algorithm 算法 alteration of message 改变消息 application level attack 应用层攻击 argument 变量 asymmetric key cryptography 非对称密钥加密 attribute certificate属性证书 authentication 鉴别 authority 机构 availability 可用性 Abrupt junction 突变结 Accelerated testing 加速实验 Acceptor 受主 Acceptor atom 受主原子 Accumulation 积累、堆积 Accumulating contact 积累接触 Accumulation region 积累区 Accumulation layer 积累层 Active region 有源区 Active component 有源元 Active device 有源器件 Activation 激活 Activation energy 激活能 Active region 有源（放大）区 Admittance 导纳 Allowed band 允带 Alloy-junction device 合金结器件 Aluminum(Aluminium) 铝 Aluminum – oxide 铝氧化物 Aluminum passivation 铝钝化 Ambipolar 双极的 Ambient temperature 环境温度 Amorphous 无定形的，非晶体的 Amplifier 功放扩音器放大器Analogue(Analog) comparator 模拟比较器 Angstrom 埃 Anneal 退火
外文翻译院（系） 专业班级 姓名 学号 指导教师 年月日
Programmable designed for electro-pneumatic systems controller John F.Wakerly This project deals with the study of electro-pneumatic systems and the programmable controller that provides an effective and easy way to control the sequence of the pneumatic actuators movement and the states of pneumatic system. The project of a specific controller for pneumatic applications join the study of automation design and the control processing of pneumatic systems with the electronic design based on microcontrollers to implement the resources of the controller. 1. Introduction The automation systems that use electro-pneumatic technology are formed mainly by three kinds of elements: actuators or motors, sensors or buttons and control elements like valves. Nowadays, most of the control elements used to execute the logic of the system were substituted by the Programmable Logic Controller (PLC). Sensors and switches are plugged as inputs and the direct control valves for the actuators are plugged as outputs. An internal program executes all the logic necessary to the sequence of the movements, simulates other components like counter, timer and control the status of the system. With the use of the PLC, the project wins agility, because it is possible to create and simulate the system as many times as needed. Therefore, time can be saved, risk of mistakes reduced and complexity can be increased using the same elements. A conventional PLC, that is possible to find on the market from many companies, offers many resources to control not only pneumatic systems, but all kinds of system that uses electrical components. The PLC can be very versatile and robust to be applied in many kinds of application in the industry or even security system and automation of buildings.
UNIT 1 A 电路 电路或电网络由以某种方式连接的电阻器、电感器和电容器等元件组成。如果网络不包含能源，如 电池或发电机，那么就被称作无源网络。换句话说，如果存在一个或多个能源，那么组合的结果为有源网络。在研究电网络的特性时，我们感兴趣的是确定电路中的电压和电流。因为网络由无源电路元件组成，所以必须首先定义这些元件的电特性. 就电阻来说，电压-电流的关系由欧姆定律给出，欧姆定律指出：电阻两端的电压等于电阻上流过的电流乘以电阻值。在数学上表达为: u=iR (1-1A-1)式中 u=电压，伏特；i =电流，安培；R = 电阻，欧姆。 纯电感电压由法拉第定律定义，法拉第定律指出：电感两端的电压正比于流过电感的电流随时间的 变化率。因此可得到：U=Ldi/dt 式中 di/dt = 电流变化率，安培/秒； L = 感应系数，享利。 电容两端建立的电压正比于电容两极板上积累的电荷q 。因为电荷的积累可表示为电荷增量dq的和或积分，因此得到的等式为 u= ，式中电容量C是与电压和电荷相关的比例常数。由定义可知，电流等于电荷随时间的变化率，可表示为i = dq/dt。因此电荷增量dq 等于电流乘以相应的时间增量，或dq = i dt，那么等式 (1-1A-3) 可写为式中 C = 电容量，法拉。 归纳式(1-1A-1)、(1-1A-2) 和 (1-1A-4)描述的三种无源电路元件如图1-1A-1所示。注意，图中电流的参考方向为惯用的参考方向，因此流过每一个元件的电流与电压降的方向一致。 有源电气元件涉及将其它能量转换为电能，例如，电池中的电能来自其储存的化学能，发电机的电能是旋转电枢机械能转换的结果。 有源电气元件存在两种基本形式：电压源和电流源。其理想状态为：电压源两端的电压恒定，与从 电压源中流出的电流无关。因为负载变化时电压基本恒定，所以上述电池和发电机被认为是电压源。另一方面，电流源产生电流，电流的大小与电源连接的负载无关。虽然电流源在实际中不常见，但其概念的确在表示借助于等值电路的放大器件，比如晶体管中具有广泛应用。电压源和电流源的符号表示如图1-1A-2所示。 分析电网络的一般方法是网孔分析法或回路分析法。应用于此方法的基本定律是基尔霍夫第一定律，基尔霍夫第一定律指出：一个闭合回路中的电压代数和为0，换句话说，任一闭合回路中的电压升等于电压降。网孔分析指的是：假设有一个电流——即所谓的回路电流——流过电路中的每一个回路，求每一个回路电压降的代数和，并令其为零。 考虑图1-1A-3a 所示的电路，其由串联到电压源上的电感和电阻组成，假设回路电流i ，那么回路总的电压降为因为在假定的电流方向上，输入电压代表电压升的方向，所以输电压在（1-1A-5）式中为负。因为电流方向是电压下降的方向，所以每一个无源元件的压降为正。利用电阻和电感压降公式，可得等式(1-1A-6)是电路电流的微分方程式。 或许在电路中，人们感兴趣的变量是电感电压而不是电感电流。正如图1-1A-1指出的用积分代替式(1-1A-6)中的i，可得1-1A-7 UNIT 3 A 逻辑变量与触发器
英语原文 NUMERICAL CONTROL Numerical control(N/C)is a form of programmable automation in which the processing equipment is controlled by means of numbers, letters, and other symbols, The numbers, letters, and symbols are coded in an appropriate format to define a program of instructions for a particular work part or job. When the job changes, the program of instructions is changed. The capability to change the program is what makes N/C suitable for low-and medium-volume production. It is much easier to write programs than to make major alterations of the processing equipment. There are two basic types of numerically controlled machine tools：point—to—point and continuous—path(also called contouring).Point—to—point machines use unsynchronized motors, with the result that the position of the machining head Can be assured only upon completion of a movement, or while only one motor is running. Machines of this type are principally used for straight—line cuts or for drilling or boring. The N/C system consists of the following components：data input, the tape reader with the control unit, feedback devices, and the metal—cutting machine tool or other type of N/C equipment. Data input, also called “man—to—control link”,may be provided to the machine tool manually, or entirely by automatic means. Manual methods when used as the sole source of input data are restricted to a relatively small number of inputs. Examples of manually operated devices are keyboard dials, pushbuttons, switches, or thumbwheel selectors. These are located on a console near the machine. Dials ale analog devices usually connected to a syn-chro-type resolver or potentiometer. In most cases, pushbuttons, switches, and other similar types of selectors are digital input devices. Manual input requires that the operator set the controls for each operation. It is a slow and tedious process and is seldom justified except in elementary machining applications or in special cases. In practically all cases, information is automatically supplied to the control unit and the machine tool by cards, punched tapes, or by magnetic tape. Eight—channel punched paper tape is the most commonly used form of data input for conventional N/C systems. The coded instructions on the tape consist of sections of punched holes called blocks. Each block represents a machine function, a machining operation, or a combination of the two. The entire N/C program on a tape is made up of an accumulation of these successive data blocks. Programs resulting in long tapes all wound on reels like motion-picture film. Programs on relatively short tapes may be continuously repeated by joining the two ends of the tape to form a loop. Once installed, the tape is used again and again without further handling. In this case, the operator simply loads and
电子信息专业英语复习资料 一、基本术语（英译汉） 1.probe探针 2.real time operational system 实时操作系统 3.debugger 调试器 4.sourse code 源代码 5.software radio wireless LAN 软件无线电网络 6.base station 基站 7.top-down approach 自顶向下分析法 8.variable 变量 9.data compress 数据压缩 10.signal conditioning circuit 信号调理电路 11.Chebyshev Type Ⅰfilter 切比雪夫Ⅰ型滤波器 12.vertical resolution 垂直分辨率 13.device driver 设备驱动 https://www.doczj.com/doc/835780895.html,piler 编译器 15.template 模板 16.concurrent process 并发进程 17.object recognition 目标识别 18.Discrete Time Fourier Transform 离散傅立叶变换 https://www.doczj.com/doc/835780895.html,bined circuit 组合逻辑电路 20.impedance transform 阻抗变换器 21.voltage source 电压源22.passive component 无源器件 23.quality factor 品质因数 24.unit-impulse response 单位脉冲响应 25.noise origin 噪声源 26.Domino effect 多米诺效应 27.output load 输出负载 28.cordless phone 无绳电话 29.Antenna 天线 30.harmonic interference 谐波干涉 31.Parallel Resonant 并联谐振 32.voltage control oscillator 压控振荡器 33.adaptive delta modulation 自适应增量调制 34.amplitude modulation 调幅 二、缩略语（写出全称） 1.LSI：large scale integration 2.PMOS ：p-type metal-oxide semiconductor 3.CT：cycle threshold 4.MRI：magnetic resonance imaging 5.ROM：read-only memory 6.DRAM ：dynamic random access memory 7.TCXO ：temperature compensated X'tal (crystal) Oscillator https://www.doczj.com/doc/835780895.html,B：Universal Serial Bus 9.DCT：discrete cosine transform
What is Hydraulic? A complete hydraulic system consists of five parts, namely, power components, the implementation of components, control components, no parts and hydraulic oil. The role of dynamic components of the original motive fluid into mechanical energy to the pressure that the hydraulic system of pumps, it is to power the entire hydraulic system. The structure of the form of hydraulic pump gears are generally pump, vane pump and piston pump. Implementation of components (such as hydraulic cylinders and hydraulic motors) which is the pressure of the liquid can be converted to mechanical energy to drive the load for a straight line reciprocating movement or rotational movement. Control components (that is, the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid, flow rate and direction. According to the different control functions, hydraulic valves can be divided into the village of force control valve, flow control valves and directional control valve. Pressure control valves are divided into benefits flow valve (safety valve), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusting the valves, flow diversion valve sets, etc.; directional control valve includes a one-way valve , one-way fluid control valve, shuttle valve, valve and so on. Under the control of different ways, can be divided into the hydraulic valve control switch valve, control valve and set the value of the ratio control valve. Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oil dollars. Hydraulic oil in the hydraulic system is the work of the energy transfer medium, there are a variety of mineral oil, emulsion oil hydraulic molding Hop categories. Hydraulic principle It consists of two cylinders of different sizes and composition of fluid in the fluid full of water or oil. Water is called "hydraulic press"; the said oil-filled "hydraulic machine." Each of the two liquid a sliding piston, if the increase in the small piston on the pressure of a certain value, according to Pascal's law, small piston to the pressure of the pressure through the liquid passed to the large piston, piston top will go a long way to go. Based cross-sectional area of the small piston is S1, plus a small piston in the downward pressure on the F1. Thus, a small piston on the liquid pressure to P = F1/SI,Can be the same size in all directions to the transmission of liquid. "By the large piston is also equivalent to the inevitable pressure P. If the large piston is the cross-sectional area S2, the pressure P on the piston in the upward pressure generated F2 = PxS2 Cross-sectional area is a small multiple of the piston cross-sectional area. From the type known to add in a small piston of a smaller force, the piston will be in great force, for which the hydraulic machine used to suppress plywood, oil, extract heavy objects, such as forging steel. History of the development of hydraulic