Harmonic Impact of Rectifiers Served by Unbalanced Three-Phase Sources

A converter is a rectifier or inverter which is intended to transfer electrical energy between AC and DC busses. A common industrial converter usually employs the familiar Graetz bridge configuration and usually has a rating in the kilowatt through lower megawatt range. The operation of such a device is nominally in the balanced three-phase mode in which the phase currents are nonsinusoidal. The Fourier series components of these currents, or harmonics, have been studied extensively, but relatively little has been done in the unbalanced operating mode. The principal goal of this research is to examine how unbalance in magnitude and phase of the AC supply alters the frequency spectrum of a line-commutated power converter. The topics considered in this thesis are for cases of small unbalance, infinite inductance in the DC circuit (Ldc = OO), and pure resistance in the DC circuit (Ldc= 0). Also, symmetrical component analysis is made, and reasons for the presence of uncharacteristic harmonics are studie

A Virtual Classroom Via Dataconferencing: A Multi-Institutional Experience

This paper presents the experience of five faculty from four universities who are co-developing and team teaching courses using the world-wide web (WWW). In particular two novel power engineering courses, Flexible Control of Transmission Systems and Flexible Control of Distribuction Systems, introduce the student to the application of power electronic-based controllers, known specifically as flexible AC transmission systems (FACTS) controllers, to enhance the performance of the transmission and distribution systems in an electric power system. In order to leverage faculty expertise in the various topics included in each course, a unique partnership was formed among five faculty from the following universities: University of Arkansas, Kansas State University, University of Missouri--Rolla and Purdue University. In order to achieve the most effective presentation, in the presence of geographical, cost, time and technology constraints, the co-developers decided to pursue various distance learning strategies to link the four universities together in a live interactive virtual classroom utilizing dataconferencing software and the WWW. In this paper we address the trials and tribulations of our experience. In particular, we discuss the use of video tape technology by mail, the use of live audio and video via an integrated service digital network (ISDN) approach, and lastly, dataconferencing software in conjunction with telephone conferencing. Each of these alternative methodologies are examined in detail and are compared and contrasted from a cost and pedagogical point of view based on our experience

Collaborative Distance Education in Power Engineering

This paper presents a perspective on offering shared-courses, or courses simultaneously offered at two or more universities via various distance educational frameworks. Over a three year duration, two senior/graduate level courses were jointly developed and offered to the students at the University of Missouri--Rolla, the University of Arkansas, Kansas State University, and Purdue University. This paper discusses the various distance educational technologies including two-way audio/visual via ISDN line, video-tapes, and web-based conferencing. Both instructor and student reactions to these mediums are included. Pedagogical methods appropriate for these mediums are outlined. The paper concludes with recommendations and strategies for engineering institutions who would like to course-share with other universities and industry

A Multi-Institutional Cooperative Approach to Power Engineering Education

This paper describes the multi-institutional cooperative effort between the University of Missouri--Rolla, Kansas State University, and the University of Arkansas to develop two new courses in flexible power system control

Novel High Frequency Silicon Carbide Static Induction Transistor-Based Test-Bed for the Acquisition of SiC Power Device Reverse Recovery Characteristics

A test system is presented that utilizes a high-frequency Silicon Carbide (SiC) Static Induction Transistor (SIT) in place of the traditional MOSFET to test reverse recovery characteristics for the new class of SiC power diodes. An easily implementable drive circuit is presented that can drive the high-frequency SIT. The SiC SIT is also compared to a commonly used Si MOSFET in the test circuit application

Role of Laboratory Education in Power Engineering: Is the Virtual Laboratory Feasible? Part I

IEEE PES sponsors a panel session in the summer power meeting in Seattle on laboratory education in power engineering. Six short papers and one full paper summarize the opinions of the panelist. This paper contains the summary of four of the presentations. The objective of the panel is to discuss the role of laboratory education in power engineering at both the graduate and undergraduate level. The question is what type of laboratory course is needed? Power electronics, electric machines, system simulation, etc? the second objective is to assess the status and value of computer based virtual laboratories. This includes the presentation of experience with virtual laboratories and a list of available tools. The teaching of power system operation can be improved using a simulation laboratory. The available simulation tools and the assessment of their values will be an important topic of the panel. The last presentation gives opposing views, arguing for the traditional laboratory us

Integrating Research Results into a Power Engineering Curriculum

This paper presents summaries of the activities of six research active power engineering educators which were presented in a panel session of the same name at the IEEE Power Engineering Society Winter Meeting on February 3, 1997 in New York City, USA. Each of the panelists discusses how research results are incorporated into courses and how students benefit from this approach

Conversion of electrical energy from one form to another, and its management through multichip module structures

The design and fabrication of a highly integrated, intelligent integral horsepower, three-phase induction motor drive based on multichip module (MCM) technology is described. A conventional three-phase induction motor is transformed into a stand-alone variable-speed drive by way of MCM technology. This solid-state controller-known as a multichip power module (MCPM)-uses known good die (KGD) to obtain minimal footprint, volume, and mass, while maximizing efficiency, reliability, and manufacturability. This is done by integrating the low-power control and high-power sections onto a single substrate. In accordance with one embodiment of the present invention, an integrated circuit assembly formed on a single substrate is capable of transforming and controlling AC power input to DC power output responsive to input signals. In accordance with another embodiment, an integrated circuit assembly on a single substrate is capable of receiving direct current power and controlling it and transforming it to alternating current power in single phase or multiphase form having variable magnitude and/or variable frequency. In accordance with a further embodiment, an integrated circuit assembly on a single substrate is capable of receiving alternating current power and controlling it and transforming it to alternating current power in single phase or multiphase form having variable magnitude and/or variable frequency