Time-domain just-before-test verification method to detect failures and ensure the measurement accuracy for conducted emissions and immunity tests
1Universitat Politècnica de Catalunya, Spain; 2TUBITAK UME, Turkey
It is mandatory for EMC test laboratories to apply verification methodologies to ensure that they are performing the tests properly. However, the time-consumption of most of the procedures or its low accuracy causes low-impact and consequently a poor benefit for laboratories. With the aim to improve the performance of the current verification methods, a just-before-test methodology based on time-domain measurements is proposed in this publication. In order to improve the accuracy and detect failures for conducted emissions and immunity tests, arbitrary waveforms and full time-domain EMI measurement methods are combined. Hence, it is proposed to use multi-tone and pulsed waveforms to evaluate the performance of the conducted emissions test, including the receiver with normative detectors, paths and devices like LISN. On the other hand, for the immunity test, a time-domain EMI system based on the use of an oscilloscope is employed to identify defects on the amplifier, RF generator, devices like CDNs or paths. The methodologies are explained and validated through different simulated failure scenarios. Where we can identify a proper performance of the test bench or defects like poor grounding or coupling devices malfunctions.
Impact of Tower Arrangement on the Mitigation of the Electric Field Intensity on the High-Voltage Conductors
1Independent System Operator in Bosnia and Herzegovina, Bosnia and Herzegovina; 2University of Sarajevo, Faculty of Electrical Engineering
In this paper impact of the tower arrangements on the mitigation of the increased values of the electric field intensity at high-voltage transmission line conductors is investigated. Several configurations of high-voltage towers (horizontal, delta, reverse delta, vertical and split-phase configurations) were analyzed. It assumed that the same height of the lowest phases conductors above the ground and the same value of the connected 400 kV voltage. The calculations were carried out for the values of the electric field intensity on the surface of the conductor and its immediate vicinity. A charge simulation method was used to calculate the electric field intensity on the surface of the stranded conductors and their immediate vicinity.
Estimation of Electromagnetic Background Intensity Created by Wireless Systems in Terms of the Prediction of Area Traffic Capacity
Belarusian State University of Informatics and Radioelectronics, Belarus
A novel technique for estimating the level of electromagnetic background created by the wide spread wireless information services for population, is proposed. This technique is based on prediction of the total area traffic capacity processed by these systems, for estimating the average electromagnetic loading on considered area, which, in turn, is used for worst-case estimation of the electromagnetic background intensity near the ground surface. An essential dependence of the considered electromagnetic background intensity on the quality of intranetwork electromagnetic compatibility design is displayed
Analysis of different Sleeve Ferrite Cores Performance according to their Dimensions
1Department of Electronic Engineering, University of Valencia, Spain; 2Würth Elektronik eiSos GmbH & Co. KG, Germany
Sleeve ferrite core is an EMI suppressor widely used to reduce the conductive and radiated electromagnetic noise in cables. The interconnection of different electronic systems through cables is becoming more difficult due to the hard restrictions related to EMC compliance requirements. Thereby, the research of new solutions able to provide a great attenuation ratio in a wide frequency band is a challenge. This contribution focuses on analyzing and comparing the performance of a novel sleeve ferrite solution based on a nanocrystalline (NC) structure with several materials with different compositions. This component is able to provide a high initial permeability value at the same time that maintains it up to some tens of megahertz. In terms of dimensions, NC suppressors can provide the same effectiveness than other materials with more reduced dimensions. The analysis of the impedance dependence of a sleeve ferrite core with its dimensions has been carried out. Five ceramic materials with different initial permeabilities from 380 up to 5000 has been compared with the NC core through representing their impedance traces. The results presented shows that NC provides the higher impedance throughout the frequency range of 1-500 MHz when it is compared with ceramic cores with the same dimensions.
Wavelet Based Detection of Signal Disturbances in Cab Signalling System
Dnipropetrovsk National University of Railway Transport named after Academician V. Lazaryan, Dnipro, Ukraine
The problem considered in the work is concerned to the methods to reveal and identify the signal disturbances occurred in the railway cab signaling system caused by electromagnetic interference from traction current. The continuous automatic locomotive signalling system (ALSN) is a type of cab signalling systems that provides track status information to the train cab and uses the rails as a continuous communication channel between track and train. To ensure the reliability of the transmission of ALSN commands to the train cab, the basic parameters of the coded current are periodically checked for compliance with certain requirements during planned test trips of a specially equipped railway car-laboratory. The ALSN signal is received by the coils of the car-laboratory and recorded by computer. Then an operator visually analyzes the recorded signal to detect problem segments with interference exceeding the limit level what requires a lot of time and does not provide the necessary accuracy. To automate the detection and identification of the ALSN signal disturbances, the following algorithm has been proposed. At the first stage, the wavelet packet energy Shannon entropy is used to reveal problem segments of ALSN signal. At the second stage, a detailed analysis of the ALSN signal using DWPT is performed to determine the type and parameters of interference at the revealed problem segments. To classify ALSN signal disturbances, an artificial neural network was used. The efficiency of the proposed algorithm was verified by processing of several specially simulated as well as real ALSN signals measured during tests.
Difference Between the Method of Moments and the Finite Element Method for Estimation of Complex Permittivity in Liquids Using a Coaxial Probe
Hachinohe Institute of Technology, Japan
In this study, the method of moments (MoM; a technique based on transverse electromagnetic (TEM) mode analysis) was applied for estimation of complex permittivity in liquids. This represents an inverse problem based on a combination of the coaxial probe approach (which facilitates measurement of liquid dielectric constants over a broad frequency range) and comparison of S11 measurement values with calculated values based on electromagnetic (EM) analysis for periods of contact with an unknown material. The dielectric constants of certain liquid types were estimated assuming contact between the sample and the flange based on an inverse problem using the 2D Newton-Raphson method to coincide with S11 values calculated using the MoM and the finite element method (FEM) at frequencies of 0.50, 1.5 and 3.0 GHz. The results of complex permittivity estimation using the MoM were also compared with set dielectric property values associated with S11 calculation using the FEM. The difference between each value in the material constant relating to S11 calculation was then quantitatively calculated. Sample results include differences of 0.374 to 1.238% for the real part and 0.107 to 0.837% for the imaginary part in the complex permittivity of pure water with MoM application using the coaxial-probe approach as compared to FEM application.
Fade analysis in DAB+ SFN network in Wroclaw
Wroclaw University of Science and Technology, Poland
The article presents the method of determining the places of occurrence of the largest fades caused by signals from two transmitters of the SFN DAB + in the Wroclaw network as an example. These locations were determined for a pair of transmitters. The method of determining the depth of fades was described, based on a propagation model for a flat, perfectly conductive ground. The selective character of the fades resulting from the size of the signal path difference to the observation point is also presented.
Theoretical and experimental study on electromagnetic induction from power line against multi-point grounded conductors
NTT EAST Corp, Japan
Electromagnetic induction between power lines and telecommunication cables has been studied since early 1900’s, because such induced voltage may cause physical injury to service personnel, and malfunction of telecommunication equipment or quality degradation of telecommunications. On the other hand, induction against suspension wires that support overhead telecommunication cables has been studied less because its structure can be complicated and it is connected to grounds at multiple points. In this paper, we have studied induction phenomena against multiple point grounded conductors, theoretically and experimentally. Firstly, we replaced the induction model with an equivalent mesh circuit and calculated voltages at each grounded point. Secondly, we measured node voltage at each grounded point using a 1:1000 scale model to confirm accuracy of the calculation model for ideal and real conditions. From these results, the calculated results are in good agreement with the experimental results for ideal conditions. However, the experimental and calculated results of real conditions have some errors at the edge of the node voltage. Thus, we intend to improve the measurement setup and calculation model in our future work.
Analysis of Radiated EMI in single switch ZVS applied to induction cooking
1Universitat Politècnica de Catalunya, Spain; 2Universidad de Zaragoza, Spain
In this paper the radiated EMI generated by a single switch ZVS inverter in the non-optimal mode operating conditions, including a current peak reduction methods are analysed. These methods consist of apply a burst pulse at begin of the control signal in order to force the transistor to work in the ohmic region. The objective of this paper is evaluated the best way to apply the current peak reduction method without to radiate EMI performance degradation. According experimental results, when the burst pulse is modulated in frequency, an amplitude attenuation of far-field emission is observed.
Why Frequency Domain Tests Like IEC-61000-4-19 Are Not Valid; a Call For Time Domain Testing
1University of Twente, Netherlands, The; 2THALES Nederland B.V., Netherlands, The
Testing of electrical and electronic equipment is performed using frequency domain tests like the IEC 61000-4-19. This standard covers the immunity to conducted, differential mode disturbances and signaling in the frequency range from 2 kHz to 150 kHz. Previous research describes several electromagnetic interference (EMI) cases in this frequency range, which cover pulsed, fast changing, current waveforms. For example cases are described were static energy meters can give misreadings when loaded with pulsed currents. Fast changing time domain signals are not covered by the standards. In this paper it shown that the current frequency domain tests are not sufficient to determine the equipment’s immunity, because the non-linear behavior makes the system non linear time invariant (LTI).
An integrated solution for electromagnetic perturbation computing of railway track with real traffic conditions and applications
A new calculation method to estimate the interference current of an electrified railway network is presented and discussed. This program takes into account two intertwined needs: the correct assessment of electromagnetic (EM) perturbation and the accurate estimation of the currents due to the trains’ traffic. This paper shows how and why these latter parameters should be considered in order to optimize and reduce the interference current.
Global Optimization Techniques for Optimal Placement of HF Antennas on a Shipboard
1ASELSAN Inc. Turkey, Turkey; 2ASELSAN Inc. Turkey, Turkey
In studies  and , RF coupling between two VHF antennas on an aircraft platform is minimized by determining an optimal antenna placement with techniques, Genetic Algorithm Optimization (GAO) and Particle Swarm Optimization (PSO). Based on these studies, in this work; RF coupling between two HF antennas on a shipboard platform is minimized by determining optimal antenna placements by GAO and PSO techniques. Unlike the other studies in literature, coupling is minimized not only at single frequency but over the whole frequency band of operation of the antennas. Throughout this work, outputs of two optimization techniques are compared with each other in terms of antenna placements and coupling results. Finally, in order to guarantee sufficient directivity and coverage of the antennas at their optimal places, far-field radiation pattern performances of the antennas are analyzed.
Autonomous electromagnetic mapping system in augmented reality
1IFSTTAR, France; 2IRCICA/CRIStAL; 3LUXONDES
Mapping or scanning the electromagnetic emissions of electronic cards or any environment requires the use of relatively complex mechanical or electronic. These systems may be difficult to transport and not well suited to performing measurements in confined environments. Moreover, they can require long acquisition times. Autonomous, compact and fast, the scanning system proposed in this article aims to overcome these constraints. It makes it possible to map the electromagnetic environment directly on site or in locations difficult to access, such as inside a vehicle for example. This scanner is composed of a smartphone coupled to removable EM field sensors to allow covering different configurations. Exploiting an augmented reality technique, it has an interface that allows communication via USB between the smartphone and the various sensors. In this paper, the device is described and measurements results illustrating its potential are presented.
An Effective Approach to Mitigate IC Radiated Susceptibility in EM Far-Field Region
ESEO-IETR, RF-EMC Research Group, France
An effective approach to mitigate the radiated susceptibility of integrated circuits (ICs) to electromagnetic (EM) disturbances in far-field zone is described. It relies on dielectric loading which confines the reactive fields inside the dielectric load to improve the immunity of ICs independently of frequency without impairing IC performance. A transverse electromagnetic (TEM) cell was used to simulate and measure loaded and unloaded versions of an IC. An indirect measurement demonstrated that the susceptibility of a commercial microcontroller (ATMEL SAM3S4B) was significantly reduced (~ 48\% less failure rate for a loaded compared to an unloaded IC) thanks to that technique. Moreover, it was shown that the immunities to both E- and H-fields were enhanced in presence of a non-ferromagnetic dielectric material being much less expensive than commonly used ferrites. The overall results demonstrate the effectiveness of the proposed technique as a potential candidate to mitigate the radiated susceptibility of electronic devices.