Power supply design in the undergraduate curriculum

Even though the electronic power supply is one of the most commonly used circuits, its design is often mentioned only briefly in undergraduate curricula. The approximate analyses in most textbooks fail to cover the RMS current requirements of the transformer, and they are not sufficiently detailed for the use in the design of power supplies. The common case of low-voltage ripple is seldom addressed. This paper presents a power supply analysis suitable for design in the undergraduate curriculum. By using ordinary scientific calculators available to most students, it is possible to design common power supplies and to determine the various nonsinusoidal currents and voltages in the power network. Straightforward methods are provided to determine the peak and RMS current requirements of the components     

Incorporating instructional feedback in electrical engineeringlaboratory experiments-an example

The advantages of incorporating software tools, other than simulation packages, in electrical engineering laboratory experiments are discussed in this correspondence. This approach supports the prerequisite lecture material and allows study and understanding of some practical issues which are best handled through a laboratory experiment. It is also shown that only through software can instructional feedback be easily integrated in the students' work. Time and effort are optimized and difficulties in assimilating the material and correlating the results are minimized. A detailed laboratory experiment, namely performance analysis of an induction motor, which is significantly enhanced with the support of a software package called Mathead, is provided as an example     

Laboratories for an undergraduate course in power electronics

Laboratory exercises to accompany an undergraduate power electronics course are discussed. Topics include inductors, periodic steady state, drive circuits, PWM control, average switch models, and startup. These laboratories present an evolutionary sequence of increasingly difficult, design-oriented power electronics laboratories     

长沙地区变压器经济运行

在简述变压器的有功功率损耗计算方法和经济运行区间概念的基础上,结合长沙地区电网实际,指出可以实行经济运行的变电站,并提出实行主变经济运行需要解决的技术问题.     

Teaching microwave amplifier design at the undergraduate level

Many textbooks on the subject of microwave amplifier design contain redundant material that may overload and confuse a student confronting microwave amplifiers for the first time. Some topics such as unilateral gain and unilateral design are often not necessary in this day of personal computing where exact gain and gain circle calculations can easily be used. Stability circles can be used to both identify allowable values of source and load reflection coefficients for the transistor and ascertain whether or not the transistor is unconditionally stable. By eliminating redundant topics and emphasizing the dual role of stability circles, instructors are able to effectively teach undergraduate students in a relatively short time design methods for narrow-band low-noise amplifiers, both single-stage and multistage, which employ either conditionally or unconditionally stable transistors.     

Senior design project: undergraduate thesis

Engineering design has become a critical element of the undergraduate engineering curriculum. To become accredited by the Accreditation Board for Engineering and Technology (ABET) requires that at least 24 credits of design content be included in the four-year undergraduate engineering curriculum. Senior design is the principal course in which students apply their knowledge in several disciplines to one project assignment and is a significant step towards meeting ABET requirements. Engineering experience acquired in the senior design course is a valuable aid to students as they learn how to apply theory to an actual design project. The senior design course develops project management and oral and written communication skills and enables students to learn scheduling, team coordination and cooperation, parts ordering, and cost/performance tradeoffs. Ten senior design projects that have won IEEE and SME student paper contests are presented herein as a guide in the difficult selection of suitable design topics. The unique nature of the senior design course requires certain departures from usual engineering course organization if students are to derive the maximum benefit. Senior design is nearly equivalent to an industrial internship and may be more valuable as the first step a student takes in making the transition to working engineer     

An undergraduate VLSI CMOS circuit design laboratory

The author describes a structured, 13-week series of laboratory exercises which demonstrates very large scale integrated (VLSI) CMOS digital circuit design and simulation for undergraduates in electrical engineering. He also suggests cost effective measures that could make the laboratory exercises economically feasible for vocational schools, colleges, and universities     

电磁兼容性设计在电源系统设计中的应用

电磁兼容性是衡量电子产品质量的一个重要指标,电磁兼容性设计可以提高电子产品的安全性。针对电磁兼容性对电子产品的影响,介绍了电磁兼容性设计在电源系统设计中的主要应用方法和注意事项,并以实例说明电磁兼容性设计对电源控制系统的影响。     

Increasing student interest and comprehension in power engineeringat the graduate and undergraduate levels

This paper reports on new efforts in the modernization of the basic undergraduate courses and a graduate curriculum in electric power engineering. The main focus of the paper is the modernization of the way power engineering is portrayed to students. The motivation is the recognition of the new deregulated and restructured environment in power engineering and the broadening of the area in general. At the undergraduate level, a multimedia approach is described in which renovation of the curriculum is done in such a way as to allow broadening of the subject material. At the graduate level, new efforts in power electronics and electric power quality are described. The implementations of changes as those reported here were made at several universities including Arizona State University     

Power system stabilizers as undergraduate control design projects

The use of power system stabilizers (PSS) to damp power system swing mode oscillations is of practical importance. The design of PSS is taught in graduate level courses on power system dynamics and control, and has been the topic of numerous M.S. and Ph.D. theses. This paper discusses the experience in assigning PSS projects in an undergraduate control design course to provide students with a challenging design problem using three different techniques and to expose them to power system engineering. The details of the PSS design projects using root-locus, frequency-domain, and state-space methods are provided.     

Transformer design and application considerations for nonsinusoidalload currents

The use of adjustable-speed drives requires transformers capable of withstanding high levels of harmonic currents under normal operating conditions. Experience has been that overheating problems are much more common with dry-type transformers than with liquid-filled transformers. Transformer insulation life is determined by the hot spot temperature but confirmation of hot spot temperature rise is one performance characteristic which is ignored in industry standards. This is especially important for transformers rated for nonsinusoidal load currents. The design of transformers for nonsinusoidal load currents should include an analysis of the eddy loss distribution in the windings and calculation of the hot spot temperature rise. Calculations and thermal tests giving only average winding temperature rises are not sufficient. Thermal tests with nonsinusoidal currents and measurements of hot spot temperature rises are extremely difficult on large transformers. The combination of testing and analysis may be the only economically practical approach. Analysis indicates that the dry type transformer hot spot temperature is very sensitive to the eddy loss magnitude and distribution. The Underwriters Laboratories Inc. (UL) K-factor rated dry type transformer and the recommended practices given in ANSI/IEEE C57.110 are reviewed. When purchasing transformers subject to nonsinusoidal load currents, considerations should be given to the manufacturer's development program and capability to calculate the eddy loss distribution and hot spot temperatures     

主电路模块化设计在大功率电源中的应用

在大功率电源产品的结构设计中,主电路的结构设计至关重要。本文提出了一种用于三相独立叠层母线电源的主电路模块化设计的思路。每相独立成为一个单元,有独立的散热器和风道,便于功率模块的散热,满足热设计的要求,便于产品的安装及维护。     

浅谈电力通信谐振型电源系统的构成

电源故障而导致的通信系统中断占了较大的比例。各种功率开关模块和谐振型电源专用集成控制电路大量应用，大大促进了谐振型电源设备应用和发展。文章分析了谐振型开关电源工作原理及其特点，简介了谐振型开关电源系统的模块组成及其功能。     

华北地区风电场部分箱变故障原因分析

近年来随着中国风力发电的大规模发展,各种故障频发。箱变是风力发电场的主要设备之一,其故障多少会在较大程度上影响风电场的发电效益。本文结合某风电场多台箱变故障实例与多年的风电场设计咨询经验,对目前华北地区正在建设和已经运行的风电场中美式箱变出现的故障和原因进行了汇总,为不同环境下箱变的采购和技改提供参考意见。     

Computer aided instruction of power transformer design in theundergraduate power engineering class

This paper describes a single-phase transformer design suitable for classroom use. The scope of this design is limited to the specification for the core and coils of the transformer. Both shell and core configured transformers are designed in this paper. A computer program is developed for the purpose of illustrating the design procedure and demonstrating how it works. The objective is to meet all performance requirements at minimum cost     

火力发电厂交流保安电源系统设计浅析

介绍在火力发电厂交流保安电源设计过程中,对交流保安负荷在功能、接线、特殊性等方面应注意的一些问题,介绍了事故保安负荷的种类.     

Using PSpice in teaching impulse Voltage testing of power transformers to senior undergraduate students

This paper describes an efficient method of teaching impulse voltage testing of power transformers to undergraduate students of power system groups in electrical engineering departments, as a part of a high-voltage course for senior undergraduate students. The paper shows how to simulate the power transformer and impulse generator to teach students the basics of impulse voltage testing of power transformers and to practice analyzing the test results. In the first part of the paper, the effect of wave shaping of the voltage waveform is simulated to teach the behavior of the impulse generator, and in the second part, impulse voltage testing of a transformer is simulated. Evaluation of the simulation over several semesters with more than 80 students is very positive in terms of their developing confidence in an understanding of this test.     

大容量有源电力滤波器的研究与设计

针对大容量有源电力滤波器(APF)的研究与设计,首先基于自适应原理的谐波检测方法,提出采取一种新的变步长LMS谐波检测算法,仿真结果证明该检测方法不仅具有很快的动态响应速度,还具有很好的精度;在此基础上继而对APF的关键硬件设计进行分析,并阐述了大容量APF主电路功率器件的选择以及主电路的布局设计;最后根据实际需要基于Lab VIEW设计了APF的远程控制软件,实现了APF整机的研究与设计。实际补偿效果测试也证明了有源电力滤波器软件算法与关键硬件部分设计的合理性。     

Integrating design into undergraduate honors theses in a computerengineering program: an experiment

ABET recognizes the practical component or design as a key ingredient of any successful engineering program and mandates its inclusion in every engineering curricula. This paper is the result of a seven-year long experiment by the author that was initiated in 1989 as an attempt to integrate the tradition of undergraduate honors research at Brown University (USA) with the emerging ABET requirement of engineering design in the computer engineering program. The paper presents the philosophical principles, the underlying assumptions and goals of the experiment, and the character of the experiences learned at the conclusion of the experiment