2012 届本科毕业设计(论文)外文
文献翻译
学 院： 电气与自动化工程学院 专 业： 测控技术与仪器 姓 名： 学 号：
外文出处：Proc. of the 8th WSEAS Int. Conf. on Mathematical Methods and Computational Techniques in Electrical Engineering, Bucharest, October 16-17, 2006
附 件： 1.外文资料翻译译文；2.外文原文
附件1：外文资料翻译译文
与LabVIEW相关的电子测量
Dambovita
摘要---本文介绍了数据采集系统，包括一个霍尔效应传感器，数据采集板6023(美国国家仪器公司)，虚拟仪器LabVIEW图形编程环境和实验所取得的交流电路和作者所预期的电路行为一致。该仪器用于计算机数据测量和输入的基础设备，利用确定的职能（获取参数，信号处理/修改）来达到在在串行口或并行口通信的目标。现在数据采集板可以直接安装到计算机上面使用，且具有调节参数功能的示波器。LabVIEW可视化的编程环境下对于研究自动化和新开发的应用是非常有利的，由用户界面和可视化编程组成。
关键词---数据采集，图形化编程，霍尔效应，电功率
1．简介
使用LabVIEW的图形化编程环境，保证了分析、研究单相和三相交流电路[ 3，6，7 ] 功率测量的实现。所有这两种电子测量技术的发展，在电子器件领域和数据采集系统该领域，对于新设备的设计提供可行性建议，用来提高在这方面的研究成果 [ 2，3 ]。
现代计量与其他快速增长的领域是紧密相连的，如计算机技术，数据处理技术和电子通信技术。为了适应信息系统技术的需要，测量系统创建了一个新的跨学科领域处理分布式测量控制系统（DMCS）。DMCS元素（节点）分布地域，通过有线或无线网络连接，彼此之间能够交换信息。目前的研究主要集中在DMCS面积的适用性问题、新信息调整和这种系统的通信技术[8]。
如今，在DMCS的技术非常重要的问题是保证通信的安全。在许多情况下，往往通过昂贵的实验或课题才能实现，而社会和经济的安全性又取决于这种系统正确的运作。由于和社会紧密相连的计算机网络仍在增长，分散式测量系统的安全性系统却在减少。在这个有着非常多信息的网络，安全性成为主要的发展问题之一。信息安全问题也非常重要（因为这个系统具有开放性，很容易受到攻击），在无线和移动DMCS系统。由于DMCS节点既可以是所谓的测量服务器，通常是依据拥有庞大的PC处理能力，以及用电池供电移动无线传感器，现有的计算
功能成为解决问题的另一个重要常用的方法，从而确保了DMCS的安全。因此目前迫切需要制定适当的方法和工具以确保这些系统[1，8]的安全。
现在的软件系统在测量系统中起着巨大的作用，也往往决定了他们的质量。日益增长的处理器计算能力和内存容量允许发展更多的复杂软件。低成本和易于使用的软件设计、提供独立的信息和使用信息和通信基础设施的安全交换库和工具成为创造新的分布式测量系统设计方法和工具的一个重要问题。
现有的软件专门为DMCS设计的工具，如LabVIEW的集成软件环境、LabWindows / CVI、HPVEE，使开发过程变的简单和灵活，但其中不包括安全的数据交换库。安全问题只有轻微的考虑，已造成一定的访问控制机制如基于登录名和密码识别系统引入到应用程序的某些部分（前面板及其组件）。但有没有使用加密方法，节点之间的信息发送明确，主要是一个纯文本。
因此，似乎有必要制定一个完整的程序和工具，并针对特定的编程环境，安全的分布式测量系统，这将使应用程序或系统的开发在一个简单而直观的方式来设计和模拟。添加这些程序应有助于确保数据的安全传输，在任何通信基础设施和新建的测量系统对控制数据有完整的认证机制。
在以前的工作中，作者分析了LabVIEW环境的能力，为有效实施加密算法[1]。本文中所描述的在下一阶段的工作，是发展新的数学工具LabVIEW环境 - 大量库（又称大整数或任意长度的整数库）。这个库允许对任意数量的计算（限制在可用内存之内）的小数位数，远远超过在计算机系统的典型代表（32或64位）。大批被广泛使用在许多流行的加密算法，包括RSA，拉宾的ElGamal公钥加密系统，使用数据加密和安全的数字签名的产生[2,3]。除了基本的算术运算在合适的维数或有限的操作数模N，计算在相反的元素如代数和素性测试算法的功能。
本文介绍了大数库的LabVIEW环境的实施方案。本文的主要目的是，以不同的方式显示在LabVIEW环境中实施加密算法，并将给予进一步研究是有帮助的工具，因为他是实施特定的算法的基础。该论文还提供了有关的公共密钥加密系统的基本理论知识，在建立安全和可靠的DMCS它被认为是有用的。这样一个简短的教程，应该有助于更好地理解主题。纸张安排如下：在第2节，我们目前最流行的非对称加密算法（公开密钥加密算法），并显示开发库，它可以处理
大量的数字运算。下一步，我们不久向数论的图书馆，由维克多舒普开发[7,10]，这将作为参考软件（第3节）和针对LabVIEW的Crypto-G的库[9]，这是不够的实际使用中，由于缺乏非对称加密系统（在第4节）。在第5节，我们提出了两个变种，我们的公告资料库执行的问题：第一，在本地的LabVIEW图形化语言，第二，在外部模块基于C+ +的。然后，在第6节，显示两者的准确性和效率测试的结果。在最后一节，我们完成我们的工作和给予的建议，为进一步开展工作如LabVIEW环境中实现加密工具库。
论文包含了分布式测量控制系统和通信等系统，特别是安全问题涉及的领域。显示了DMCS软件的巨大的作用，并提出需要制定一些这样的系统加密工具的方法。这些工具将使开发人员有机会以一个简单而直观的方式设计安全系统。 这些工具将使DMCS的发展成为一个用简单而直观的方式所设计的安全系统的机会。本文提供的基本理论知识的公共密钥加密系统，用以建立安全和可靠的DMCS被认为是有效的。该论文的主要目标是提出新的LabVIEW中的大数库，这是为进一步落实具体的非对称算法，如RSA或拉宾加密系统所必需的数学工具。DMCS实施了两个变种：只有本地的LabVIEW代码（G语言），使用外部软件模块（DLL）。实现的功能进行了测试，测试的结果是导致以下结论。
有一种可能性用来实现在纯G代码大数库。这样一个解决方案的效率可能是和类似的版本相当，使用外部软件模块的快速算法和一些代码的优化步骤进行。纯G代码编写的大数库不仅可用于在DMCS的基于PC的模块，也可以直接从LabVIEW环境中使用基于FPGA硬件的LabVIEW FPGA模块编程的解决方案。
2．单相交流电路中的功率测量
2.1 在交流电路中提供的动力
电偶极子中的偶极子和电流（I）的瞬时功率[1,2,3,4]，通过偶极子流动终端产品的电压瞬时值（U）定义为：
p=ui （1）
瞬时间发生的功率可分为瞬时输入功率和瞬时输出输出功率，瞬时功率取决于瞬时总电压（U）和电流（I），符合接收者功率和发电机功率相同的规则。在正弦波T期间的稳定状态，有功功率（P）可以被定义为瞬时功率的平均值，考虑一
个自然数的周期：
表达式为：
一种单相电路的功能，在一个正弦波固定的变化速度，其中的电压和电流的
它的结果：
-有功功率：P = UIcosψ
-无功功率：Q = UIsinψ (5) -视在功率：S = UI
复杂的视在功率（S）定义为简单化复杂的代表性表达式之间复杂的电压（U）和共轭复数（I*）：
复杂的功率（S）的实部是有功功率（P），虚部是无功功率（Q），模块是视在功率（S）和说法是相等于相位平移（φ）电路：
对于一个单向电路并不能被正弦波[4]所定义，它的端电压U（T）为：
他们可定义为： - 有功功率：
- 无功功率：
- 视在功率：
S=UI (11)
考虑到上述 的关系，我们可以看到S ²≠P ²+Q ²变形的概念，因此可以推出:
下面的应用程序（图1）通过使用LabVIEW图形化编程环境，对所现在提出的理论思考的基础上可以实现实现[2,5,6,7]，当前的图形显示中可以允许显示电压随时间的变化，瞬时的有功功率。通过对控制元件的电压和充电阻抗参数修改，也可以用于指示电压，电流，功率因数，有功，无功和视在功率（为了获得准确的视图目前，可以调节的振幅有1，10，20，50或100倍）。
图1 单相交流电路的操作和功率测量 - 模拟
数据采集板是一个复杂的系统，它使用传感器在允许的工艺参数进行测量和监测，它可以转化成电能的电压研究物理措施[1,3,4,6,7]。必要的单相交流电路被应用在电路板的输入电压范围的幅度信号。相/线电压，电阻分压器（不保证电气隔离）或电压测量变压器（确保电隔离）都可以使用。可用于电流分流器（电流 - 电压转换器）或电流测量变压器。分压器和分流的使用必须要考虑通过分压器的电流，分流，功耗，寄生电阻，自热效应，动态效果上的电压降。
图2.数据采集系统
图3 实验结果
电压，电流测量变压器的使用，强大的系统功能保证了电流所产生的影响与测量系统的电气隔离，但它引入了比例和角度误差，造成微小的传输扰动。所采用的解决办法是在霍尔效应的基础上使用电压和电流的传感器。采集系统方块框图在图2中表示，并且图3呈现出来的是实验结果。
注释：图中的电压值和用户设置的参数在图3a ，引入模拟（图1）实现了应用程序的功能。
3．在三相交流电路的功率测量
对于一个包含线性阻抗的随机接收器（Z），形成了一个具有n个节点，这是通过一个具有n个导体的电路放大的与导线[1]复杂，总共视在功率（S）发送到接收器是：
通过使用报点的电位差的节点表示的潜力N个含有一个随机的潜在的电位差，成为表达（3.1）：
（14）
有功和无功功率的定义，结果如下：
总的有功功率P（不包括无功功率Q）的消耗由一个具有n个阶段的线路接收器随机接收，并通过n个导体线传输，等于n个使用单相的电（或无功的单相电）的总和这是IK线电流之间的n导体和N点UkN电压。 替代三相电路有以下电压系统：
如果电压系统提供了一个三阶段的平衡接收机，当前的系统将是：
如果相位阻抗是不同的，那么接收器是不均衡的，从源头上吸收的电流可以与有关星型三相连接的平衡接收机的方法计算，它的结果是：
关于中性导体阻抗（Z0）的值，电压的值将会是：
数据采集系统的方块框图如图4所示。在三相交流电路中，有功功率/无功功率的测量方法，是依赖于负载的类型和电能供应系统导体的类型。
图4数据采集系统 - 框图
对于三相电路包含的中性导体数为（N= 4），广义定理将会改变成：
在这种情况下，总的有功功率可以使用4瓦特计算法（一个随机值将会考虑给到将会出现潜在的N点），或者使用3瓦特计法（如果存在潜在的N点，是等于一个衡量中性导体）。
图5 数据采集系统的实验结果
4结论
应用程序采用LabVIEW图形化编程环境（模拟和数据采集）的实施，已实现使用正确的设备在基础理论方面和在实验室的实验测定。这些应用程序可以被用于研究功率的测量方法（学生/人员培训，因为修改电路参数的能力和效果显示）和执行高精度测量。信号调理系统的使用，扩大了在电力系统的数据采集能力，用来研究电动机，转换器的运作。仪器的灵活性方面，包括在测量过程中的其他业务（分析，操作自动化，访问数据的基础上，发送在互联网上的数据等），在减少操作方面成为可能性。
参考文献
[1] Dogaru-Ulieru,V. – Electrical and Electronic Measurements, Ed. Printech, Bucharest, 2005
[2] Dogaru-Ulieru,V., s.a.- LabVIEW Application in Electrical Measurements, Ed.CONPHYS, Rm. Valcea, 2002
[3] Ertrugul, N. – LabVIEW for Electric Circuits, Machines, Drives, and Laboratories, Pretince Hall PTR, NJ, 2002
[2] Dogaru-Ulieru,V., s.a.- LabVIEW Application in Electrical Measurements, Ed.CONPHYS, Rm. Valcea, 2002
[4] Golovanov, C., s.a – Measurements Modern Issues in Electroenergetics, Ed. Tehnica, Bucharest, 2002
[5] Maier, V.,s.a–LabVIEW in Quality of Electric Energy, Ed. Albastra, Cluj-Napoca, 2000
[6] ***National Instruments, LabVIEW – User Manual, LabVIEW – Data Acquisition Basics Manual, Academic Resources 2004 [7] *** www.lem.com,*** www.ni.com
附件2：外文原文
Electric Measurements with LabVIEW
Dambovita
Abstract: The paper presents a data acquisition system which consists in Hall effect sensors, a PCI 6023(National Instruments) data acquisition board, Lab VIEW graphical programming environment and the experimental results achieved by the authors concerning the behavior of ac electrical circuits. The instruments used in the measurement technique were developed as computer data base equipments, using well determined functions (the acquisition of parameters, signal processing/adapting) with the communication possibility on a serial interface or on a parallel port. Today, data acquisition boards are used and can be assembled directly into the computer, having the operation possibility of an oscilloscope. The appearance of the LabVIEW environment was motivated by the research automation activity and by the application development, based on a hierarchical instrument structure, which is composed by the user's interface and the visual programming elements.
Keywords：data acquisition, graphical programming, Hall effect, electric power
1 Introduction
The use of the LabVIEW graphical programming environment ensures the analysis and study of power measurement methods in single-phase and three-phase alternative current circuits [3, 6, 7]. The evolution in both electric measurement technique, in the electronic field and in the area of data acquisition systems, arguments the opportunity and justification of designing new instruments in order to improve the research activity in this area [2, 3].
The modern applied metrology is integrally linked with other fast-growing domains, such as computer technology, data processing and telecommunications. Adaptation of the information systems’ techniques for the needs of measurement systems created a new interdisciplinary field dealing with Distributed
Measurement-Control Systems (DMCS). Elements of DMCS (nodes) are distributed territorially, connected via wired or wireless network and able to exchange
information between each other. Currently the research in the area of DMCS is focused on the applicability issues and adapting of new information and
communication technologies for such systems [8]. Nowadays, a very important issue in DMCS technology ensures the safety of communication. In many cases, the success of often costly experiments or missions and also the biological and economical security depends on the proper functioning of such systems. Due to the still growing integration with telecommunications and general public computer networks, the security of distributed measurement systems has been dramatically reduced. In many DMCS the information security of the network becomes one of the major
development problems. Information security issues are also very important (because of the specific openness of such systems, and ease of attack) in the wireless and mobile DMCS systems. Since the nodes of DMCS can be both socalled Measuring Servers, usually based on PCs with huge processor power, as well as mobile wireless sensors powered from battery, the existing disparity of calculation power makes another important issue for the development of common methods, ensuring the safety of DMCS. Therefore there is an urgent need to develop proper methods and tools to ensure the safety and security of these systems [1, 8].
The software plays nowadays a huge role in measurement systems and very often determines their quality. The growing processors’ computing power and memory capacity allows for the development of more complex software. An important issue becomes the creation of new methods and software tools for designing distributed measurement systems, and in particular low-cost and easyto- use libraries and tools for designing software that provides secure exchange of information independently of used information and communication infrastructure.
Existing software design tools dedicated for DMCS, integrated software environments such as LabVIEW, LabWindows/CVI, HPVEE, enable simple and flexible development process of applications, but among others do not include libraries for secure data exchange. The security problem was only slightly considered which has resulted in the introduction of certain access control mechanisms to certain parts of an application (front panels and their components) based on login and
password identification system. But there is no use of cryptographic methods, and the information between nodes is sent explicitly, mostly as a plain text.
Therefore, it seems necessary to develop a complete library of functions, programs and tools tailored to specific programming environments, which would give the application or system developer the opportunity to design and simulate secure and safe distributed measurement system in an easy and intuitive way. These additives should help to ensure safe transmission of data in any communication infrastructure and the creation of mechanisms for authentication and integrity of both measurement and control data.
In the previous work, the authors have analyzed the LabVIEW environment capabilities for efficient implementation of cryptographic algorithms [1]. The next phase of the work, described in this paper, is to develop new mathematical tool for LabVIEW environment - a Large Number library (also known as Big Integer or arbitrary length integer library). This library allows for the computation on numbers with arbitrary (within the limits of available memory) number of decimal digits, far exceeding the typical representation in computer systems (32 or 64bit). Large numbers are widely used in many popular cryptographic algorithms, including RSA, Rabin or ElGamal public-key encryption systems, used for both, data encryption and the generation of secure digital signatures [2,3]. The LN library in addition to basic arithmetic operation includes operation modulo N in the suitable rings or finite bodies, functions for calculating the opposite element in such algebras and primality test algorithms.
2. Power Measurement in Single-Phase AC Circuits
The instantaneous power [1,2,3,4] to an electric dipole is defined as the product of the instantaneous values of the voltage (u) to the terminal of the dipole and the current (i) that flows through the dipole:
P=ui (1)
The instantaneous power can be classified into input and output power, depending on the association of the voltage (u) and the current (i), which respects the
rule of receivers and generators. In a sine-wave steady-state with the T period, the active power (P) can be defined as the average value of the instantaneous power, considering a natural number of periods:
For a single-phase circuit which functions under a sine-wave permanent rate, in which the voltage and current have the following expressions:
it results:
- the active power: P = UIcosϕ
- the reactive power: Q = UIsinϕ (5) - the apparent power: S = UI
The complex apparent power (S) is defined into the simplified complex representation as the product between the complex voltage (U) and the conjugate complex current (I*):
The real part of the complex power (S) is the active power (P), the imaginary
part is the reactive power (Q), the module is the apparent power (S) and the argument is equal to the phase displacement (ϕ) of the circuit:
For a single-phase circuit which does not function in sine-wave rate [4] and has the terminal voltage u(t):
there can be defined: the active power:
the reactive power:
the apparent power:
S=UI (11)
By taking into account the relations above, we can notice that S ²≠P ²+Q ² and therefore the notion of deforming power can be introduced:
The application below (fig. 1) which is realized by using the LabVIEW graphical programming environment, basing on the presented theoretical considerations [2,5,6,7], allows the graphical display of the time variation of the voltage, the current, the instantaneous and active power. Control elements are used in order to modify the voltage and the charge impedance parameters, and also other elements are used for indicating the voltage, the current, the power factor, the active, reactive and apparent power (in order to obtain an accurate view of the current, it is possible to multiply the amplitude 1, 10, 20, 50 or 100 times).
Fig.1. Single-Phase AC Circuits Operation and Power Measurement – simulation
2.2 Signal Conditioning
The acquisition data board is a complex system which allows parameter measurement and monitoring from a technological process, using transducers which can transform studied physical measures into electrical voltage [1,3,4,6,7]. For single-phase ac circuits, it is necessary to obtain signals with voltage-range amplitude, to be applied at the input of the board. For phase/line voltages, resistive voltage dividers (do not ensure galvanic isolation) or voltage measurement transformers (ensure galvanic separation) can be used. Shunts (current-voltage converter) or current measurement transformers can be used for currents. The use of both voltage dividers and shunts must be done by taking into account the current through the voltage divider, the voltage drop on the shunt, the power dissipation, parasite resistances, self-heating effects, dynamic effects.
Fig.2. Data acquisition system
Fig.3. Experimental results
The use of voltage-current measurement transformers ensures the energetic system’s galvanic isolation of the measuring system, but it introduces ratio and angle errors and realizes an inadequate perturbation transfer. The adopted solution was to use current and voltage transducers based on the Hall effect. The block diagram of the acquisition system is presented in fig.2 and fig.3 presents the experimental results.
Remark: The voltage values and the parameters of the consumers in fig. 3a, were introduced into the application realized for simulation (fig.1).
3. Power Measurement in Three-Phase AC Circuits
For a random receiver (Z), consisting in linear impedances, forming a system with n nodes which is alimented through a circuit with n conductors [1], the total complex apparent power (S) transmitted to the receiver is:
By expressing the potentials of the nodes using the potential differences reported to a point N having a random potential, the expression (3.1) becomes:
(14)
The definitions of active and reactive power give the following results:
The total active power P (respectively the reactive power – Q) consumed by a random receiver with n phases and alimented through a line of n conductors, is equal to the sum of n active single-phase powers (or reactive single-phase powers) which
are given by the Ik line currents, with the UkN voltages between the n conductors and the N point. The alternative three-phase circuits have the following voltage system:
If the voltage system supplies a three-phase balanced receiver, the current system will be:
If the phase impedances are different, the receiver is not balanced and the absorbed currents from the source can be calculated with methods that are related to star connected three-phase balanced receivers, it results:
Regarding the impedance value of the neutral conductor (Z0), the voltage value will be:
Fig.4. Data Acquisition System – block diagram
The block diagram of the data acquisition system is presented in fig.4. The measuring methods for active/reactive power in three-phase ac circuits, depend on the type of the consumer and the number of conductors in the electric energy supply system.
For three-phase circuits with neutral conductor (n=4), the generalized theorem becomes:
The total active power in this case can be measured by using the 4 wattmeter method (if a random value is given to the potential of the N point) or using the 3 wattmeter method (if the potential of the N point is equal to the one of the neutral conductor).
Fig.5. Data Acquisition System –experimental results
4 Conclusion
The implementation of the applications (simulating and data acquisition) into the LabVIEW graphical programming environment has been realized basing on
theoretical aspects and experimental determinations in the laboratory, using accurate devices. These applications can be used both for studying the measurement methods of power (student/personnel training because of the ability of modifying the parameters of the circuits and of the effect display) and for performing high accuracy measurements.
The use of the presented signal conditioning system enlarges the data acquisition abilities in the electric system, in order to study the operation of electric machines, converters, transient rates. The flexibility of the instrument is given by the possibility of including other operations in the measurement process (analysis, operation automation, access to the data basis, sending data on the Internet, etc.).
References
[1] Dogaru-Ulieru,V. – Electrical and Electronic Measurements, Ed. Printech, Bucharest, 2005
[2] Dogaru-Ulieru,V., s.a.- LabVIEW Application in Electrical Measurements, Ed.CONPHYS, Rm. Valcea, 2002
[3] Ertrugul, N. – LabVIEW for Electric Circuits, Machines, Drives, and Laboratories, Pretince Hall PTR, NJ, 2002
[4] Golovanov, C., s.a – Measurements Modern Issues in Electroenergetics, Ed. Tehnica, Bucharest, 2002
[5] Maier, V.,s.a–LabVIEW in Quality of Electric Energy, Ed. Albastra, Cluj-Napoca, 2000 [6] ***National Instruments, LabVIEW – User Manual, LabVIEW – Data Acquisition Basics Manual, Academic Resources 2004 [7] *** www.lem.com,*** www.ni.com
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