Showing papers on "Electromagnetic compatibility published in 2004"

Electromagnetic interference (EMI) reduction from printed circuit boards (PCB) using electromagnetic bandgap structures

Abstract: As digital circuits become faster and more powerful, direct radiation from the power bus of their printed circuit boards (PCB) becomes a major concern for electromagnetic compatibility engineers. In such multilayer PCBs, the power and ground planes act as radiating microstrip patch antennas, where radiation is caused by fringing electric fields at board edges. In this paper, we introduce an effective method for suppressing PCB radiation from their power bus over an ultrawide range of frequencies by using metallo-dielectric electromagnetic band-gap structures. More specifically, this study focuses on the suppression of radiation from parallel-plate bus structures in high-speed PCBs caused by switching noise, such as simultaneous switching noise, also known as Delta-I noise or ground bounce. This noise consists of unwanted voltage fluctuations on the power bus of a PCB due to resonance of the parallel-plate waveguiding system created by the power bus planes. The techniques introduced here are not limited to the suppression of switching noise and can be extended to any wave propagation between the plates of the power bus. Laboratory PCB prototypes were fabricated and tested revealing appreciable suppression of radiated noise over specific frequency bands of interest, thus, testifying to the effectiveness of this concept.

Electromagnetic compatibility handbook

Abstract: EMI Sources Decibel and Approximations Electrical Length Fast Bode Magnitude Plotting Skin Depth, Wire Impedance, and Nonideal Resistors Nonideal Capacitors and Inductors Passive Filters Cable Modeling Transient Behaviour in the Time Domain Air Breakdown Transient Behaviour in the Frequency Domain Spectra of Periodic and Aperiodic Signals Transmission Lines and Matching Passive Contact Probes Inductance, Magnetic Coupling, and Transformers Magnetic Materials and a Few Devices Baluns and Balanced Circuits Cable Shielding and Crosstalk Radiated Emissions and Susceptibility Conducted Emissions and Susceptibility Plane Wave Shielding Electric Field Shielding Magnetic Field Shielding Additional Shielding Concepts Test Chambers Floating Metal and Guard Electrodes Electrostatic Discharge Grounding Circuit Board Layout for EMC Antenna Appendix A-Summary of the Three Major Coordinate Systems Appendix B-Definitions for Common and Uncommon Functions Appendix C-Conversion, Unit and Notation Tables Appendix D-Helpful Mathematical Relationships References

EMI study of a three phase inverter-fed motor drives

Abstract: Today, electromagnetic compatibility (EMC) seems to be one of the major constraints of power electronic converters, particularly for variable-speed drives. Unfortunately, it is too often regarded as the last phase of the development of a converter since it represents the last step of its marketing. The estimation of conducted and radiated disturbances by simulation offers a considerable gain from the economic point of view. This paper shows how relatively simple models can be used to forecast EMC, taking into account various control strategies. These models are validated on an experimental setup and can be used during the design of a variable-speed inverter motor association. The objective is to approach by “fast” simulations the conducted emission to consider optimization processes. It is then imperative to take into account the environment of the converter, which implies the modeling of cables, motors, and, naturally, the filters.

Predicting the breakdown behavior of microcontrollers under EMP/UWB impact using a statistical analysis

Abstract: Reproducible prediction of damaging effects is one of the main problems in intentional electromagnetic interference (IEMI). In this paper, the susceptibility of different types of single microcontrollers to unipolar fast rise time pulses [electromagnetic pulse (EMP), ultrawide band (UWB)] is determined. Therefore, pulses with rise times as fast as 100 ps and electric field amplitudes of up to 100 kV/m are applied to the devices. The results are generalized with a novel statistical procedure. Following discussion and rationale, the Weibull distribution is selected to describe the interference behavior. The statistical analysis provides a new test procedure for a confident determination of the interference behavior parameters.

Numerical coupling models for complex systems and results

Abstract: The paper gives a status of present electromagnetic (EM) coupling modeling capabilities. Starting from topologically designed systems, it shows how formal rules of the EM topology approach can provide guidance for EM coupling analysis or the development of protection against intentional electromagnetic interference (EMI)- related threats, even in the case of a poorly shielded system. After a review of currently available mature numerical techniques, a strategy allowing one to chain different numerical tools (including three-dimensional analysis tools, cable-networks tools, and circuit analysis procedures) is proposed in order to achieve EM coupling assessments on real complex systems. The paper also gives a status on several scientific trends likely to enhance modeling capabilities in the future.

Characterization of human Metal ESD reference discharge event and correlation of generator parameters to failure levels-part I: reference event

Abstract: Electrostatic discharge (ESD) generators are used for testing the robustness of electronics toward ESD. Most generators are built in accordance with the IEC 61000-4-2 specifications. Using only a few parameters, this standard specifies the peak current, the rise time and the falling edge. Lacking a transient field specification, test results vary depending on which generator is used, even if the currents are quite similar. Such a specification is needed to improve the test repeatability. As for the current, the specification should be based on a reference human metal ESD event. While keeping the presently set peak current and rise time values, such a reference ESD (5 kV, 850-/spl mu/m arc length) is identified and specifications for current derivative, fields, and induced voltages are derived. The reference event parameters are compared to typical ESD generators.

Application of a hybrid finite difference/finite volume method to solve an automotive EMC problem

Abstract: In this paper, we present a hybrid finite difference/finite volume method and we apply it to solve an automotive electromagnetic compatibility (EMC) problem. The principles of the hybrid method and the numerical schemes are described. Simple examples are used to compare this method with the finite difference and finite volume methods alone in terms of accuracy and computing speed. The automotive EMC problem and its modeling are then presented. Finally, sample comparisons between measurements and calculations of both electric fields and S-parameters between an antenna and cables are given.

Cellular phone base stations installation violate the compatibility regulations

Abstract: In mobile telecommunication, radio frequency waves that are used to carry the intelligence of cell phone calls is actually the electromagnetic energy transmitted through space Electronic equipments such as medical devices, radio amateur etc that is located nearer to the cellular phone base station receives much more electromagnetic energy that can adversely affect its operations thereby cause interference This paper presents a case study in China (Wuhan) that investigates the effect of electromagnetic radiation on electronic equipment due to base stations built on top of or near hospitals, clinics and residential buildings The path from the base station transmitter through the air was examined and later linked to the electromagnetic field theory to build models of different paths for interfering signals which were sustained by simulation The conditions determining the risk of interference were considered The main purpose of this paper is to study the existing standards such as EMC-directive in regard to interference on electronic equipments and to disseminate the EMC education about the cellular phone base stations installations

Linear and nonlinear filters suppressing UWB pulses

Abstract: In order to protect electronic systems against natural or man-made electromagnetic interferences with high energies and amplitudes nonlinear protection elements like spark gaps, varistors or Z-diodes are state-of-the-art countermeasures. Most of these protection circuits are designed for well studied transient interferences like lightning electromagnetic pulse, nuclear electromagnetic pulse or electrostatic discharge pulses. It is of special interest to investigate the response of common nonlinear protection elements at ultrawideband (UWB) pulses with significant amplitudes, rise times in the picosecond range and pulse durations of a few nanoseconds. It is discussed whether traditional protection concepts provide a sufficient protection against such extremely fast pulses. Furthermore the possibility of linear filtering is presented with focus on the protection of high frequency datalines.

A new technique for modeling and analysis of mixed-mode conducted EMI noise

Abstract: This work presents a new technique for modeling and analysis of the mixed-mode (MM) electromagnetic interference (EMI) noise. The analytical MM noise model is first investigated to get a full understanding of the EMI mechanism. It is shown that with the suitable and justified model, many practical filters pertinent to MM noise are investigated, and the noise attenuation can also be derived theoretically. The analysis and results proposed here can provide a guideline for future effectiveness of filtering schemes in switch-mode power supplies.

New propagation models for electromagnetic waves along uniform and nonuniform cables

Abstract: This paper discusses the mathematical modeling of the propagation of electromagnetic energy along nonuniform transmission lines. This electromagnetic energy can either be transmitted signals or disturbances caused by electromagnetic interference. Emphasis is laid on the basic ideas behind the transmission-line super theory and the solution of the corresponding telegrapher equations. We show how to establish these telegrapher equations for nonuniform transmission lines and how to calculate the per-unit-length parameters. Afterwards we discuss several solution methods, like numerical integration techniques and semi-analytical approaches. With selected examples we demonstrate the application of our new tools.

Accurate modeling of layout parasitic to forecast EMI emitted from a DC-DC converter

Abstract: This paper illustrates how to account for all parasitic due to the layout of a power converter (inductive and capacitive), in order to forecast electromagnetic interferences (EMI). The method is generic, and is validated here in the simple example of a DC-DC converter, realized on different technologies: insulated metal substrate (IMS), printed circuit board (PCB). In addition, several layouts aspects will be investigated. Conclusions are given on the influence of layout and all other components on EMI.

Differential mode EMC input filter design for three-phase AC-DC-AC sparse matrix PWM converters

Abstract: The design of a differential-mode EMC input filter for a three-phase AC-DC-AC very sparse matrix converter intended for electrical machine drive applications is discussed in this paper. A review of the steps to be performed in the course of the filter design is presented and a detailed mathematical model of the EMI test receiver for quasipeak measurement of conducted emissions in the frequency range of 0.15...30 MHz is established. Furthermore, formulas for the estimation of the quasipeak detector output based on the LISN output voltage spectrum are provided. As experimentally verified by using a novel three-phase CM/DM separator this procedure allows an accurate prediction of the converter differential mode conducted emission levels and therefore could be employed in the design process for ensuring compliance to relevant EMC standards.

Integrated EMI Filters for Switch Mode Power Supplies

Abstract: Because of the switching action, power electronics converters are potentially large EMI noise sources to nearby equipment. EMI filters are necessary to ensure electromagnetic compatibility. Conventional discrete EMI filters usually consist of a large number of components, with different shapes, sizes and form factors. The manufacturing of these components requires different processing and packaging technologies, of which many include labor-intensive processing steps. In addition, due to the parasitics of discrete components, high-frequency attenuation of the filter is reduced and the effective filter frequency range is limited. As a result, discrete EMI filters are usually bulky, high profile, and have poor high-frequency performance. With an aim to solving these issues, this study explores the integration of EMI filters. The goal is to achieve a smaller size, lower profile, better performance and reduced fabrication time and cost via structural, functional and processing integration. The key technology for EMI filter integration is planar electromagnetic integration, which has been a topic of research over the last few years. Most of the previous applications of this technology for switch mode power supplies (SMPSs) were focused on the integration of high frequency power passive electromagnetic components, such as HF transformers, resonant/choke inductors and resonant/blocking capacitors. Almost no work has been done on the subject of EMI filter integration. Since the major function of EMI filters is to attenuate, instead of propagate, energy at the switching frequency and its harmonics, the required technology and design objectives are very different from those of other components. High-frequency modeling of the integrated structure becomes more essential since the high-frequency performance becomes the major concern. New technology and a new model need to be developed for EMI filter integration. To bridge this gap between existing technologies and what is necessary for EMI filter integration, this dissertation addresses technologies and modeling of integrated EMI filters. Suitable integration technologies are developed, which include reducing the equivalent series inductance (ESL) and equivalent parallel capacitance (EPC), and increasing, instead of reducing, the high frequency losses. Using the multi-conductor lossy transmission-line theory, a new frequency domain model of integrated LC structure is developed and verified by experimental results. Through detailed electromagnetic analysis, the equations to calculate the required model parameters are derived. With the developed frequency domain and electromagnetic model, the characteristic of integrated LC modules can be predicted using geometry and material data. With the knowledge obtained from preliminary experimental study of two integrated EMI filter prototypes, a technology is developed to cancel structural winding capacitance of filter inductors. This can be realized by simply embedding a thin conductive shield layer between the inductor windings. With the…

Full-wave simulation of electromagnetic coupling effects in RF and mixed-signal ICs using a time-domain finite-element method

Abstract: This paper describes the computer simulation and modeling of distributed electromagnetic coupling effects in analog and mixed-signal integrated circuits. Distributed electromagnetic coupling effects include magnetic coupling of adjacent interconnects and/or planar spiral inductors, substrate coupling due to stray electric currents in a conductive substrate, and full-wave electromagnetic radiation. These coupling mechanisms are inclusively simulated by solving the full-wave Maxwell's equations using a three-dimensional (3-D) time-domain finite-element method. This simulation approach is quite general and can be used for circuit layouts that include isolation wells, guard rings, and 3-D metallic structures. A state-variable behavioral modeling procedure is used to construct simple linear models that mimic the distributed electromagnetic effects. These state-variable models can easily be incorporated into a VHDL-AMS simulation providing a means to include distributed electromagnetic effects into a circuit simulation.

New broadband EMC double-ridge guide horn antenna

Abstract: Broadband antennas, due to the large frequency bands required by standards,are the work horse of electromagnetic compatibility testing. Traditionally theantenna parameter of interest to the EMC engineer was the antenna factor. Theadvent of higher frequency testing has brought the development of a newdouble-ridge guide horn design.

Transient Response of Grounding Systems Caused by Lightning: Modelling and Experiments

Abstract: In order to achieve better lightning protection and electromagnetic compatibility (EMC) requirements, the needs for a proper grounding system and the knowledge of its transient behaviour become cru ...

Analysis of chip-level EMI using near-field magnetic scanning

Abstract: Integrated circuits (ICs) are often a significant source of radiated energy from electronic systems. Well designed ICs maintain good control of the currents that they generate. However, poorly designed ICs can drive high-frequency noise currents onto nominally low-frequency input and output pins. These currents can excite unintentional radiating structures on the printed circuit board, resulting in radiated emissions that are difficult or expensive to control. The paper discusses the use of magnetic near-field scanning techniques to measure the current distribution in IC packages. This technique is applied to common ICs, including a clock driver, a memory module and a field programmable gate array (FPGA). Results show that near-field magnetic scanning is an effective tool for investigating chip-level EMI problems.

A practical approach to EMC education at the undergraduate level

Abstract: In view of the importance of electromagnetic compatibility (EMC), universities worldwide are paying more attention to training electronic engineers with good EMC design knowledge. As part of the EMC training, a practical printed circuit board (PCB) layout project has been offered as an elective to the undergraduates in the authors' universities. The project requires the students to design the PCB layout of a standard digital circuit twice, the first time with no EMC consideration at all, and the second time with careful EMC consideration. The significant difference in the levels of radiated emissions of the two layouts allows the students to appreciate the importance of EMC design at an early stage of product development.

Electromagnetic compatibility management for fast diagnostic design

Abstract: This article presents an overview of electromagnetic compatibility (EMC) management for fast diagnostic design. We will present and detail the classical approach in EMC. This approach can be successfully applied for installations where a single engineering entity has the authority to prescribe and enforce a certain compatibility level. Most of the time, strict application of generic standards is required for fast diagnostics. Nethertheless, the pulse perturbation must be synchronized to the fast diagnostic operation. Some “traditional” techniques, such as star-earthing and bonding cable screens at one end, have been shown to be inadequate for fast diagnostic design. Our laser facility, the LIL, will be able to focus up to 60 kJ into a volume of less than 1 mm3. We have to evaluate the electromagnetic pulse (EMP) where diagnostics, cables, and oscilloscopes will be installed. We performed electromagnetic measurements inside and outside the OMEGA target chamber. The electromagnetic pulse generated by the ta...

Modeling induction machines for EMC-Analysis

Abstract: EMC-analysis of power electronic systems is strongly supported by network simulations. Simulations at the system level provide not only the prediction of EMI but also deep insight into the EMC relevant effects. To model the system properly, it is necessary to model source and target of EMI and also all parts of the coupling paths. EMI-filters can be designed efficiently using network based modeling approaches. In this paper a model for induction machines' EMC behaviour simulation is parameterized in the frequency range from some kHz up to 100 MHz. The high-frequency characteristics of induction machines with power ratings from 370 W up to 45 kW are compared and a model library is set up for both, frequency and time domain.

General electromagnetic compatibility analysis for nonlinear microwave integrated circuits

Abstract: The paper proposes a new solution to the standard electromagnetic compatibility problem for nonlinear RF/microwave integrated circuits. Radiation from the given circuit is first numerically analysed by means of electromagnetic simulation. Under the assumption of a uniform plane wave incident on the circuit, the reciprocity theorem is then used to characterize the linear subnetwork by a Norton equivalent circuit. Finally, a multitone harmonic-balance analysis allows the effects of the incident wave on the circuit electrical regime to be exactly investigated.

Why EMC immunity testing is inadequate for functional safety

Abstract: Safety-implicated, safety-related, and safety-critical systems are increasingly using electrical, electronic and programmable electronic devices. All such devices can suffer malfunctions or damage due to electromagnetic interference. Safety systems have safety integrity requirements (defined by IEC 61508) - but their EMC aspects are not adequately controlled by either safety or EMC standards. The paper describes the shortcomings in the way that the EMC immunity of such equipment is dealt with, and shows that the normal immunity testing approach is inadequate, on its own, as a means of verifying this aspect of safety integrity.

Novel technologies for microwave and millimeter-wave applications

Abstract: 1 Review of Electromagnetic Theory.- 2 Efficient Simulators and Design Techniques for Global Modeling of High-Frequency Active Microwave Devices.- 3 Band-Pass Filter Design with Genetic Algorithms.- 4 Design of Multistage Combline Band-Pass Filters in Layered Structures.- 5 Millimeter Wave Filters for Low-Cost Mass Fabrication.- 6 High-Temperature Superconducting Planar Filters for Wireless Communication.- 7 Micromachined Devices for Wireless Communication.- 8 Introduction to Low-Temperature Cofired Ceramics Technology.- 9 Analysis of Spiral Inductors Embedded in Layered Media.- 10 Guidance Properties of Strips in an Inhomogeneous Layered Medium.- 11 Microstrip Lines with a Periodically Corrugated Ground Plane.- 12 Theory and Applications of Electromagnetic Band Gap Structures.- 13 Finite Element Methods for Microwave Engineering.- 14 Dielectric Resonator Antennas on Printed Circuit Boards.- 15 Multiband and Wideband Patch Antennas.- 16 Phased Antenna Array Based on Nonlinear Delay Line Technology.- 17 Spatial Power Combiners Using Active Planar Arrays.- 18 Introduction to Smart Antenna Systems.- 19 Generation of Wideband Electromagnetic Responses Using Early-Time and Low-Frequency Data.- 20 Asymptotic High Frequency Methods.- 21 Ka-Band Channel Models for Low-Earth-Orbit Satellites.- 22 Channel Modeling for Land-Mobile Communication Systems.- 23 Electromagnetic Compatibility in Microwave Engineering.- 24 Electrical Packaging for Microwave and Millimeter Wave Circuits.- 25 Introduction to Cellular Systems.- 26 Introduction to Wireless Local Area Networks.

An unconditionally stable higher order ADI-FDTD technique for the dispersionless analysis of generalized 3-D EMC structures

Abstract: An efficient higher order alternating-direction implicit (ADI) finite-difference time-domain (FDTD) method for the unconditionally stable analysis of curvilinear electromagnetic compatibility (EMC) applications is presented in this paper. The novel algorithm launches a class of precise spatial/temporal nonstandard forms that drastically suppress the dispersion errors of the ordinary approach as time-step increases and mitigate its strong dependence on cell shape or mesh resolution. For arbitrary interface media distributions that do not follow the grid lines, a convergent transformation based on a rigorous extrapolating practice is introduced. Moreover, infinite domains are successfully treated by optimized higher order curvilinear PMLs. Hence, the proposed technique achieves notable accuracy far beyond the Courant limit, subdues the ADI error mechanisms, and offers serious savings, as verified by the solution of several complex EMC problems.

An EMC evaluation of the use of unshielded motor cables in AC adjustable speed drive applications

Abstract: The most common solution for modern adjustable speed drives (ASD) is the use of induction motors (IM) fed by voltage-source inverters (VSI). The inverter generates a pulsewidth modulated (PWM) voltage, with dv/dt values of about 6 kV//spl mu/s or even more. In three-leg inverters for three-phase applications the occurrence of common-mode voltage is inherent due to asymmetrical output pulses. As a result, for electromagnetic compatibility (EMC) reasons, in most applications shielded cables are used between the inverter and the motor, implying high installation costs. The present paper discusses the use of cheaper, unshielded cables. A new method for measuring electromagnetic interference (EMI) from unshielded cables is proposed and measurement results are presented. The level of EMI is evaluated in different situations: without an output filter, with a classical LC output filter and with an advanced output filter with DC link connection. It is concluded that, from an EMC point of view, unshielded cables can give very good performance provided that a common-mode (CM) output filter is used.

Electromagnetic compatibility characterisation of the DC side in a low power photovoltaic plant

Abstract: This paper presents an analysis of the electromagnetic compatibility of low power photovoltaic (PV) systems specially focused on the role of DC line. The cables connecting the PV panels to the inverter may be a source of electromagnetic emissions generated by the commutations of power electronic devices; these emissions may become radiated disturbances due to the length of the cables, so possible interference occurs even in a range below 30 MHz. Moreover the DC cables behave as a receiving antenna and the induced radio frequency (RF) currents flow via a capacitive parasitic coupling into the ground connection. Through an experimental investigation the prevalent involved electromagnetic phenomena have been pointed out. General guidelines for the high frequency modelling of the system are also addressed.

Development of high-power electromagnetic (HPEM) standards

Abstract: The International Electrotechnical Commission (IEC) is the authority for world standards in electrical and electronics engineering. The IEC technical subcommittee 77C "High-power transient phenomena" of technical committee 77 "Electromagnetic compatibility" is preparing standards and technical reports on immunity to high-altitude electromagnetic pulse (HEMP) and currently to all categories of intentional electromagnetic interference (IEMI). A short description is given of the IEC main objective, management, and organization of technical work. An overview is given of the subcommittee 77C structure, management, objectives, and sources. At present, the work comprises 17 projects of which 14 have been published. The publications and projects are discussed under the following main parts: general, environment, testing and measurement techniques, installation and mitigation guidelines, and generic standards.