EMCABS EMC Abstracts Osamu Fujiwara, Associate Editor

EMCABS:01-11-2001

ON THE AMBIGUITY OF DEFINING AND MEASURING INTERHARMONICS
Chun Li and Wilsun Xu
Department of Electrical Engineering, University of Alberta, Edmonton, Canada
IEEE Power Engineering Review, July 2001, pp. 56-57.

Abstract: This paper points out that the “fractional harmonics,” i.e., interharmonics, may be indicated by Fourier Transform measurements even when such interharmonics are not present. This results from the use of particular window sizes and locations as well as variations in the “signal” being analyzed. Since many power quality meters use window sizes covering multiple cycles, the cited ambiguity can result. On the other hand, a window size longer than one fundamental period is required to detect interharmonics. The authors suggest selection of appropriate window sizes and the repeating of measurements with different window sizes and positions to avoid these ambiguities.

Index terms: IEC Standard 1000-2-1, window effects on Fourier transforms, power quality meters, measurement of interharmonics

EMCABS:02-11-2001

AN ELECTRONIC BALLAST WITH WIDE DIMMING RANGE, HIGH PF, AND LOW EMI
S. Y. Ron Hui, Leung Ming Lee, Henry Shu-Hung Chung and Y. K. Ho
Department of Electronic Engineering, City University of Hong Kong, Kowloon, Hong Kong
IEEE Transactions on Power Electronics, Vol.16, No.4, July 2001, pp. 465-472.

Abstract: This paper describes an electronic ballast that can be used to provide dimming control of fluorescent lamps. The circuit has a high Power Factor (PF) and low emissions. The SEPIC (Single-Ended Primary Inductance Converter) provides, with high PF and low EMI, a variable dc control voltage to provide dimming control followed by a Half-Bridge LC resonant ballast driver. The disadvantages of other electronic dimmers are viewed and the advantages of this circuit are summarized, one of which is constant frequency operation. IR (Infra-Red) interference with remote control systems is also reduced. The experimental results are given including circuit details and waveforms.

Index terms: IR interference reduction, PF correction for fluorescent lamp ballast, EMI reduction by soft switching.

EMCABS:03-11-2001
ELECTROMAGNETIC ENVIRONMENTAL IMPACT OF POWER ELECTRONICS EQUIPMENT
Richard Redl ELFI S.A. En Mont vaux, Farvagny, Switzerland
Proceedings of the IEEE, Vol.89, No.6, June 2001, pp. 926-938.
Abstract: This authoritative survey paper is a good tutorial on EMC in Power Electronics. It covers line harmonics, voltage fluctuation and flicker, with emphasis on harmonics. High frequency noise sources are reviewed along with EMC standards and regulations. Mitigation techniques are covered with special cautions on line filter induced oscillations. The author includes a critique of EN 61000-3-2 and compares it to IEEE Std. 519-1992 as regards to harmonic suppression. He questions if harmonic suppression is needed at all. A good list of 47 references makes it possible to “dig deeper.”

Index terms: Power electronics EMC, line harmonics standards and regulations, power supply line filters, harmonics mitigation, noise reduction in power supplies.

EMCABS:04-11-2001
TOPOLOGIES AND DESIGN CONSIDERATIONS FOR DISTRIBUTED POWER SYSTEM APPLICATIONS
Fred C. Lee, Peter Barbosa, Peng Xu, Jindong Zhang, Bo Yang and Francisco Canales,
Center for Power Electronics Systems -CPES, The Bradley, Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0179, USA, (Jindong Zhang later joined Linear Technology Co.)
Proceedings of the IEEE, Vol.89, No.6, June 2001, pp. 939-950.

Abstract: Distributed power systems (DPS) are usually used with larger computer equipment such as servers. Circuits of choice are described for both single-phase and three-phase systems. Much of the discussion is on Power Factor Correction (PFC) “front ends,” and the other requirements for such circuits, e.g., holdup time, etc. The relative advantages and disadvantages of the major circuits are compared in light of new technology. Circuit techniques for reducing line filter size and simplifying magnetics are described. The power supply problems posed by future microprocessors are also reviewed with possible solutions. Experimental results and supporting references are included.

Index terms: Power factor correction (PFC), server power systems, power supply circuit comparisons, dc-dc converters, new power supply technology.

EMCABS:05-11-2001
LIGHTNING OVERVOLTAGES IN WIRING SYSTEMS OF THE BUILDING
L. K. Augustyniak
Technical University of Bialystok, Faculty of Electrical Engineering, Grunwaldzka 11/15, 15-893, Bialystok, Poland
Proceedings of IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, June 19-22, 2001, Saint-Petersburg, Russia, pp. 78-81.

Abstract: During a direct lightning strike into a building, there is the injection of high impulsive currents in the lightning protection system (LPS) of the building. These high currents flow through down conductors resulting in a corresponding electromagnetic field, which can induce currents and voltages in loops of conductive installation inside the building. The induced voltages can be very high and may disturb or damage the electronic equipment. This paper presents the selected results of investigations of the induced overvoltages in low voltage power supply installation (LVPI) and structural cabling systems due to electromagnetic fields from surge currents in the LPS. The trials of numerical calculations of the induced overvoltages are also included.

Index terms: Lightning, building, high impulsive currents, wiring systems, induced voltage, calculation.

EMCABS:06-11-2001
POTENTIAL DISTRIBUTIONS IN GROUNDING SYSTEMS OF TELECOMMUNICATION OBJECTS STRUCK BY LIGHTNING
R. Markowska
Technical University of Bialystok, Faculty of Electrical Engineering, Grunwaldzka 11/15, 15-893, Bialystok, Poland
Proceedings of IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, June 19-22, 2001, Saint-Petersburg, Russia, pp. 94-98.

Abstract: This paper presents the results of computations of voltage distributions in telecommunication grounding systems in case of lightning currents flows. In many cases, the voltage difference between various points of such grounding systems is much convenient value, especially in design, than for example the surge impedance of the system. For that some possible ways of reduction of these transient voltage differences from a point of view of protecting of electronic equipment have been analyzed. Those were mainly the influence of the structure of grounding system and the presence of various additional elements such as vertical ground rods and horizontal conductors. As it is shown in the paper by adding these elements, it is possible to reduce significantly these transient voltages.

Index terms: Communication towers, lightning strikes, grounding systems, voltage distribution, surge impedance, computation.

EMCABS:07-11-2001
RADIATION FROM BENT TRANSMISSION LINES
S. Lee+, M. Hayakawa+ and M. Omid++
+Department of Electronic Engineering, University of Electro-Communications, Chofu Tokyo, 182-8585, Japan
++Teheran University, Center of Informatics and Statistics, Iran
Proceedings of IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, June 19-22, 2001, Saint-Petersburg, Russia, pp. 103-107.

Abstract: This paper deals with the radiation phenomenon from bent transmission lines numerically and experimentally. At first, the radiation loss for different types of the bent transmission lines has been estimated by using the method of moments (MoM), in order to suggest the most optimal design for a bent line in terms of a radiation loss. So, the simplest line with a right-angle bend is recommended. Then, the radiation patterns from such a right-angle bent transmission line have been numerically calculated, which may indicate that the radiation is originated mainly at the bend, but other parts are also found to contribute to the overall pattern with many extra lobes. All of the numerical results were confirmed by the corresponding experiment.

Index terms: Bent transmission lines, radiation, method of moment, experiment.

EMCABS:08-11-2001
MEASUREMENT OF IC CONDUCTED EMISSIONS BY A NOVEL TECHNIQUE
F. Fiori and F. Musolino
Dipartmento di Elettronica, Politecnico di Torino C.so Duca degli Abruzzi, 24-I-10129 Torino, Italy
Proceedings of IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, June 19-22, 2001, Saint-Petersburg, Russia, pp. 134-134.

Abstract: This paper presents a new technique for the measurement of IC conducted emissions. In particular, the current spectrum of each IC port is obtained by the measurement of RF power radiated by a microstrip line in a TEM cell. This measurement method is effective since a direct relationship between transmission line radiated power and IC pin current exists.

Index terms: ICs, conducted emissions, TEM, measurement.

EMCABS:09-11-2001
ALTERNATIVE METHOD EMISSION MEASUREMENTS WITH THE USE OF HALF LOOP ANTENNAS
T. W. Wieckowski
Wroclaw University of Technology, Institute of Telecommunication and Acoustics, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland
Proceedings of IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, June 19-22, 2001, Saint-Petersburg, Russia, pp. 182-185.

Abstract: The paper herein presents various issues related to the use of half loop antennas for alternative emission measurements. The theoretical possibilities to use a half of the loop antenna supplied relative to a conductive surface have been presented for an emission measurement stand. The new type of setup for emission measurements with the use of loop antennas has been presented. The calibration procedures and sample measurement results have also been presented.

Index terms: Emission measurements, half loop antennas, double loaded loop antennas, equivalent dipoles.

EMCABS:10-11-2001
MEASUREMENT OF VOLTAGE TRANSITION DURATION AND FREQUENCY SPECTRA DUE TO MICRO GAP DISCHARGE AS LOW VOLTAGE ESD
Ken Kawamata+, Shigeki Minegishi++ and Akira Haga++
+Department of Electrical Engineering, Hachinohe Institute of Technology, 88-1 Ohbiraki Myo Hachinohe-sho, 031-8501 Japan
++Faculty of Engineering, Tohoku Gakuin University, 1-13-1 Chuo Tagajo-shi, 985-8537 Japan
Proceedings of IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, June 19-22, 2001, Saint-Petersburg, Russia, pp. 186-189.

Abstract: The transition duration due to starting of gap discharge was investigated in time and frequency domain. The transition durations were observed with a very wide-band transient digitizer. The gap space was set very small for voltages below 1500 V as a simulation of the CDM ESD and the gap discharge of switch devices. The measurement system consists of a distributed constant line system with a tapered coaxial electrode, which has the matched impedance for the characteristic impedance of the distributed constant line system. The insertion loss of the tapered coaxial electrode was within –3dB in the frequency range below 4.5GHz. The atmosphere around the electrode is ordinary air. This experimental system enables one to measure the high-speed transients of about 100 ps due to gap discharge in time domain. As a consequence of the experiment, the frequency spectra of the transition durations were 2.9GHz and over in positive polarity, while the frequency spectra were below about 2.9GHz in negative polarity.

Index terms: Micro gap discharges, voltage transition duration, frequency spectra, measurement.

EMCABS:11-11-2001
MEASUREMENT OF DISTURBANCES DUE TO THE USE OF LOW VOLTAGE POWER NETWORKS FOR DATA TRANSMISSION PROCEDURES AND RESULTS
Michel Ianoz, Emmanuel Marthe, Farhed Rachidi, Swiss Federal Institute of Technology, Power Systems Laboratory, CH-1015 Lausanne, Switzerland
Proceedings of IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, June 19-22, 2001, Saint-Petersburg, Russia, pp. 205-209.

Abstract: The use of the low voltage power network for data transmission can produce radiated disturbances. A measurement procedure which attempts to take into account the large variety of existing in house configurations has been proposed by the University of Karlsruhe. The paper describes the measurement procedure and presents experimental results on different sites. It also shows that the commonly adopted assumption of a plane wave to calculate the electric field from magnetic field measurements can lead to significant errors, especially for the determination of the indoor electric field radiation. However, these errors are within the uncertainty resulting from the large variety of indoor electrical network configurations.

Index terms: Data transmission, low voltage power network, radiated disturbances, measurement.

EMCABS:12-11-2001
RE FIELD MEASUREMENT AND THEORETICAL CALCULATION FOR CELLULAR BASE STATION ANTENNAS
Ali Ihsan Yurekli and Bahattin Turetken
TUBITAK-UEKAE EMC Laboratory, Gebze 41470 Kocaeli-Turkey
Proceedings of IV International Symposium on Electromagnetic Compatibility and Electromagnetic Ecology, June 19-22, 2001, Saint-Petersburg, Russia, pp. 320-323.

Abstract: In this study, the radiation characteristics of cellular base station antennas are investigated. As a first step, the total radiation of an array-antenna which is intended to transmit in the GSM 900 MHz band is obtained analytically. The antenna under investigation is an array of four vertical dipoles positioned along the z-axis [1-3] The method is explicit and, once the radiation characteristic of any single dipole has been calculated analytically, the general pattern of the array can then be calculated. Secondly, measurements are carried out on different points near an actual base station transmitter which is designed to transmit in the 1800MHz range. Final discussion is on the determination of the minimum distance to a BSA in order to comply with international RF safety guidelines.

Index terms: Cellular base station antennas, health hazard, radiation characteristics, measurement and calculation. EMC

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