Showing papers on "Electromagnetic compatibility published in 2010"

Progress Review of Electromagnetic Compatibility Analysis Technologies for Packages, Printed Circuit Boards, and Novel Interconnects

Abstract: The ever-increasing demands of digital computing and wireless communication have been driving the semiconductor technology to change with each passing day. Modern electronic systems integrate more complex components and devices, which results in a very complex electromagnetic (EM) field environment. EM compatibility has become one of the major issues in ICs redesign, mainly due to the lack of efficient and accurate simulation tools and expertise on noise reduction and immunity improvement. This paper reviews the state of the arts of IC, electronic package, and printed circuit board simulation and modeling technologies. It summarizes the modeling technologies for both available structures [multilayered power-ground planes and macromodeling of interconnect (INC)] and novel structures (nano-INCs and 3-D ICs based on through-silicon via technology). It also illustrates the trends of simulation and modeling technologies in EM compatibility, signal integrity, and power integrity.

Modeling Electromagnetic Emissions From Printed Circuit Boards in Closed Environments Using Equivalent Dipoles

Abstract: In this paper, a method for representing electromagnetic emissions from a printed circuit board (PCB) using an equivalent dipole model deduced from near-field scanning is proposed. The basic idea is to replace the PCB with a set of infinitesimal dipoles that generate the same radiated fields. Parameters of the equivalent dipoles are determined by directly fitting to the measured magnetic near fields. In closed-environment simulations, the equivalent method is extended to a dipole-dielectric conducting plane model to account for the interactions between the PCB and enclosure by including the basic physical features of the PCB. The electromagnetic emissions can then be predicted by solving the equivalent model with numerical methods, thereby, significantly reducing the simulation time and storage costs. A basic test board and a more complex practical telemetry PCB are modeled in different configurations and compared with measurements and full-field simulations, confirming the validity and efficiency of the model.

Accurate Extraction of Noise Source Impedance of an SMPS Under Operating Conditions

Abstract: An accurate measurement method to extract the common mode (CM) and the differential mode (DM) noise source impedances of a switched-mode power supply (SMPS) under its operating condition is developed and validated With a proper premeasurement calibration process, the proposed method allows extraction of both the CM and the DM noise source impedances with very good accuracy These noise source impedances come in handy to design an electromagnetic interference filter for an SMPS systematically with minimum hassle

Review of Printed-Circuit-Board Level EMI/EMC Issues and Tools

Abstract: A comprehensive review of printed circuit board (PCB) electromagnetic compatibility (EMC) issues, analysis techniques, and possible solutions would fill a large book or more. This review takes a quick look at where the technology of PCB EMC control has been, where it is today, and where it needs to go for the future. As data rates on PCBs have increased, new problems have arisen, requiring new analysis techniques and new solutions. Further development will be needed to keep up with the ever-increasing data rates and smaller form factors.

Effective EMI Filter Design Method for Three-Phase Inverter Based Upon Software Noise Separation

Abstract: This paper presents an electromagnetic interference (EMI) filter design method for a three-phase inverter applied to motor drives. The EMI filter design is based upon the results of software noise-separation method. Therefore, no hardware noise separator is required. Moreover, the presented EMI filter design approach provides systematic design procedure, and therefore, trial-and-error overhead is not required, and thereby, shortening the development time and saving the cost. The presented method determines common-mode choke and differential-mode choke based upon the required impedance to attenuate the noise. A three-phase inverter for inductor motor drives is used as the equipment under test (EUT), and the related conductive EMI filter is designed and verified. It will be shown that EMI filter designed by this systematic design method effectively attenuates the conductive EMI components to meet the requirement of EN 55011.

Dependability in Electronic Systems: Mitigation of Hardware Failures, Soft Errors, and Electro-Magnetic Disturbances

Abstract: Introduction.- Terrestrial Neutron-Induced Failures in Semiconductor Devices and Relevant Systems.- Electromagnetic Compatibility Power Integrity.- Dependable System Technology.

An Integrated EMI Choke for Differential-Mode and Common-Mode Noise Suppression

Abstract: This letter presents a novel integration approach for the electromagnetic interference choke. A low-permeability differential-mode (DM) choke is placed within the open window of the common-mode (CM) choke. Both chokes share the same winding structure. With the proposed approach, the footprint of inductors is greatly reduced, and high-DM inductance can be achieved. First, small-signal measurement is carried out to demonstrate the design concept and the symmetry of the proposed structure. Then large-signal experimental results verify the attenuation characteristics, as well as the thermal performance.

Investigation of the Transformation Between Differential-Mode and Common-Mode Noises in an EMI Filter Due to Unbalance

Abstract: This paper analyzes the transformation between differential-mode and common-mode noises due to the unbalance of noise sources and electromagnetic interference filters in power electronics circuits. Both insertion gain and electromagnetic interference measurements prove the analysis.

Simple Electromagnetic Modeling Procedure: From Near-Field Measurements to Commercial Electromagnetic Simulation Tool

Abstract: As the first part of a study that aims to propose tools to take into account some electromagnetic compatibility aspects, we have developed a model to predict the electric and magnetic fields emitted by a device. This model is based on a set of equivalent sources (electric and magnetic dipoles) obtained from the cartographies of the tangential components of electric and magnetic near fields. One of its features is to be suitable for a commercial electromagnetic simulation tool based on a finite element method. This paper presents the process of modeling and the measurement and calibration procedure to obtain electromagnetic fields necessary for the model; the validation and the integration of the model into a commercial electromagnetic simulator are then performed on a Wilkinson power divider.

EMC Modeling of an Industrial Variable Speed Drive With an Adapted PEEC Method

Abstract: This paper presents an adapted partial element equivalent circuit (PEEC)-based methodology applied to the modeling of interconnections of power electronics devices. Although this method is already well known, the originality of this work is its use to model a device presenting an industrial complexity. To make possible this modeling, two adapted integral methods, based on two different meshings, are presented. They are dedicated respectively to the computation of parasitic inductances and capacitances and lead to an equivalent circuit of the system. From a time-domain simulation of this circuit, current and voltage sources can be extracted and used to compute the radiated near magnetic field. This approach has been applied to model a real industrial static converter via system couplings, a variable speed drive. Good agreements have been obtained between simulated and measured results on conducted and emitted electromagnetic analysis.

EMI Noise Prediction for Electronic Ballasts

Abstract: The design of electromagnetic (EM) interference filters for converter systems is usually based on measurements with a prototype during the final stages of the design process Predicting the conducted EM noise spectrum of a converter by simulation in an early stage has the potential to save time/cost and to investigate different noise reduction methods, which could, for example, influence the layout or the design of the control integrated circuit Therefore, the main sources of conducted differential-mode (DM) and common-mode (CM) noise of electronic ballasts for fluorescent lamps are identified in this paper For each source, the noise spectrum is calculated and a noise propagation model is presented The influence of the line impedance stabilizing network (LISN) and the test receiver is also included Based on the presented models, noise spectrums are calculated and validated by measurements

Improving electromagnetic compatibility performance of packages and SiP modules using a conformal shielding solution

Abstract: High-speed digital and wireless devices radiate unintentional electromagnetic noise, which can affect the normal operation of other devices within the same system, causing intra-system electromagnetic interference (EMI) problems, or contribute to the total radiated EMI from the system, resulting in potential system-level EMI issues. PCB and system level shielding may alleviate the system-level EMI between wireless PCB board and the outside environment, but seldom prevent the intra-system EMI within the shielding enclosure. Package and System in Package (SiP) level shielding is desirable to shield the unintended radiation and protect the other circuits on board. Traditionally an external metal lid is employed to isolate the radiation from an IC, but the package cost and the size penalty due to the solder pads for shield attachment make the solution unattractive. In this paper, a new shielding technology for IC packages based on metal spray coating (conformal shielding) is presented. By spraying a conductive material on the sides of the package, a very thin metal layer is constructed around the top and four sides of a package. This very thin sprayed metal layer adds zero penalty to the package size and works similar to a solid metal shielding with very good shielding effectiveness; hence, it is suitable for wireless infrastructure, tele-communications, and high-speed digital applications.

CMOS OpAmp Resisting to Large Electromagnetic Interferences

Abstract: A CMOS operational amplifier with high immunity to electromagnetic interferences is presented. It is based on an easy modification of the differential pair with active current load. The proposed input stage can be fabricated in standard CMOS technologies, and it neither requires extra mask levels, such as triple well, nor external components. Analysis and results are provided for very large interferences, which arise from the input pin.

Layer recurrent neural network solution for an electromagnetic interference problem

Abstract: The paper presents an original contribution related to the implementation of a neural network artificial intelligence (AI) technique through Matlab environment, on the study of induced AC voltage in the underground metallic pipeline, due to nearby high voltage grids. The advantage yields in a simplified computation model compared to FEM, and implicitly a lower computational time. In comparison with other neural network solutions identified in the literature, where the induced AC potential is directly evaluated, the authors of this paper propose a new neural network solution to evaluate MVP on the studied domain, using a larger training database for a large panel of different geometries.

Design of a Common Mode Filter by Using Planar Electromagnetic Bandgap Structures

Abstract: In this paper, an embedded electromagnetic bandgap structure is proposed for harmonic filtering of differential signal's undesired common mode components. Rather than use lumped circuit components and likely causing some degradation to the intended high speed differential signal, the embedded planar common mode filter causes no degradation to the intended signal, and enhances the signal integrity and electromagnetic compatibility performance of the system. Single ended and differential traces are considered and the impact of the common mode filtering is measured in terms of mixed mode scattering parameters and eye diagram metrics. The systematic procedure to design such a structure is outlined, and its design robustness is also verified.

Common-Mode Modeling of the Association of $N$ -Switching Cells: Application to an Electric-Vehicle-Drive System

Abstract: The reliability of electronic systems is a major constraint depending on electromagnetic interference levels. Vehicle manufacturers are clearly concerned by electromagnetic compatibility studies and, especially, for electrical drive systems in which embedded power electronics is used and must, thus, be correctly designed. A global synthesis of common-mode disturbances of such equipment is pointed out in this paper and a generic model of a complex power-electronic device is presented and applied to a motor-drive system.

Magnetic Cleanliness Program Under Control of Electromagnetic Compatibility for the SELENE (Kaguya) Spacecraft

Abstract: To achieve the scientific objectives related to the lunar magnetic field measurements in a polar orbit at an altitude of 100 km, strict electromagnetic compatibility (EMC) requirements were applied to all components and subsystems of the SELENE (Kaguya) spacecraft. The magnetic cleanliness program was defined as one of the EMC control procedures, and magnetic tests were carried out for most of the engineering and flight models. The EMC performance of all components was systematically controlled and examined through a series of EMC tests. As a result, the Kaguya spacecraft was made to be very clean, magnetically. Hence reliable scientific data related to the magnetic field around the Moon were obtained by the LMAG (Lunar MAGnetometer) and the PACE (Plasma energy Angle and Composition Experiment) onboard the Kaguya spacecraft. These data have been available for lunar science use since November 2009.

Impact of a Frequency Modulated Pulsewidth Modulation (PWM) Switching Converter on the Input Power System Quality

Abstract: In this paper, we show that a frequency modulated (FM) source of conducted emission has an adverse effect on a dc power system, although it is believed that frequency modulation of the interferer reduces such effects. Spread spectrum modulation is a commonly proposed technique of electromagnetic interference (EMI) reduction. It is often suggested that an FM pulsewidth modulation ramp be used in a voltage mode controlled dc-dc switching converter for reduction of conducted and radiated EMI. However, this paper shows that this technique is not as beneficial as is commonly perceived. The power quality standard MIL-STD 704, which is the origin of the EMI standard MIL-STD 461, puts restriction on several parameters other than the frequency spectrum of the disturbance, which is the only parameter that is specified in the EMI norms and tested in electromagnetic compatibility (EMC) tests. In this paper, we show that different interferers which are compatible to the same EMC limit, may affect the same power system differently. This difference is noticed if the other power quality parameters are considered. We have also mentioned that the actual benefit from spread spectrum modulation-based EMI reduction depends on the savings in printed circuit board (PCB) footprint area that we get by using a smaller filter. Through a numerical study, we have shown that such a method leads to only a negligible savings in PCB area in spite of significant EMI reduction. Moreover, this brings about a degraded performance on the other parameters that are not normally checked in EMI tests.

PEEC-models for EMC filter layout optimization

Abstract: The subject of this paper is related to EMC filter integration Due to stray interactions between filter components and PCB tracks, or between the components themselves, the transfer function of the filter can be modified The work will first study these stray interactions and the possible electromagnetic modelling using PEEC method Then, we aim proposing an automatic procedure to determine the optimal component placement and the associated track design, in order to improve the filter transfer function Therefore, light models are needed There will be presented and validated using experimental results

A Reciprocity Approach for Computing the Response of Wiring Systems to Diffuse Electromagnetic Fields

Abstract: This paper is concerned with the problem of computing the response of a wiring system to a high frequency, short wavelength, electromagnetic field, such as that which can arise in the interior of an irradiated vehicle. It is shown that a “diffuse-field reciprocity principle” developed recently in the field of vibroacoustics can be applied to electromagnetic systems, thus, enabling the currents induced in a wiring system by diffuse electromagnetic waves to be computed in an efficient manner. With this approach only the radiation characteristics of the wiring system are required to be computed; more specifically, the impedance matrix associated with radiation into an infinite dielectric is required, and an efficient method of computing this matrix is given in the present paper, based on exact solutions to Maxwell's equations. Initially, the diffuse-field reciprocity principle is proved explicitly for one- and two-wire systems, and the method is then applied to numerical examples involving these systems. The applicability of diffuse-field theory to high-frequency interior reverberant electromagnetic fields has been verified analytically and experimentally in recent years, and this paper offers the possibility of exploiting these developments to avoid large-scale electromagnetic compatibility computations.

Automatic layout optimization of an EMC filter

Abstract: The transfer function of an EMC (Electro-Magnetic Compatibility) filter is strongly disturbed in high frequency due to stray electromagnetic phenomena. On the one hand the imperfections of the components but also all magnetic couplings on the other hand. Although these effects seem to be negative, it is possible to reduce the impacts of these imperfections on the filter response, and even to use them in order to improve its behavior. A proper arrangement of components and a clever layout of tracks are required. Nevertheless, the complexity of the problem makes unthinkable a manual construction. Therefore, this paper discusses the implementation of an automatic routing algorithm based on the PEEC method (Partial Equivalent Element Circuit), in order to consider the electro-magnetic aspect in the layout definition.

Reconfigurable chamber for emulating multipath fading

Abstract: Disclosed is a compact reconfigurable channel emulator, which may be used to emulate severe fading environments and test wireless systems and subsystems for operation in severe channel environments. Examples include radios, coding schemes, diversity methods and antennas. In particular, the chamber is well suited to test hardware associated with wireless sensor deployments for these tend to be susceptible to severe fading scenarios. Moreover, the invention is significantly smaller than traditional testing instruments, and with its automation, reduces electromagnetic interference and electromagnetic compatibility testing time and costs.

Finite-Difference Time-Domain Analysis of the Electromagnetic Environment in a Reinforced Concrete Structure When Struck by Lightning

Abstract: When a building is directly struck by lightning, the electromagnetic environment in the structure is very severe, and the conducted and radiated electromagnetic disturbances are dangerous to the information technology equipment in the building. In this paper, instead of the equivalent circuit method and method of moment used by the former researchers, the finite-difference time-domain method is applied to calculate the impulse response in a reinforced steel structure struck by lightning. Besides a reasonable concordance between the calculation results of current distribution among the vertical columns and those of former experiments, the oscillations superimposed on the current flowing along the reinforced bars, and the relation between the oscillation intensity and the soil conductivity are discussed. Furthermore, the role of a ring conductor to stabilize its interior electromagnetic field is discussed in detail.

An equivalent three-dipole model for IC radiated emissions based on TEM cell measurements

Abstract: An equivalent dipole model is proposed in this paper to represent the source of radiated electromagnetic emissions from an integrated circuit (IC). The height of an IC is usually much smaller than its length and width, so only three dipole moments are sufficient to characterize an IC in terms of its electromagnetic emissions. The dipole moments can be extracted from three TEM cell measurements. The radiated fields from the IC can then be calculated based on the extracted dipole sources. This IC emission model with three dipole moments is validated using the far-field measurements in a semi anechoic chamber for a test IC. For complex structures, it is desirable that the extracted dipole moments can be incorporated into a commercial full-wave tool as equivalent sources to simulate the radiations from an IC. This is demonstrated using an approach developed in this paper.

Simplified equivalent modelling of electromagnetic emissions from printed circuit boards

Abstract: Characterization of electromagnetic emissions from printed circuit boards (PCBs) is an important issue in electromagnetic compatibility (EMC) design and analysis of modern electronic systems. This thesis is focused on the development of a novel modelling and characterization methodology for predicting the electromagnetic emissions from PCBs in both free space and closed environment. The basic idea of this work is to model the actual PCB radiating source with a dipole-based equivalence found from near-field scanning. A fully automatic near-field scanning system and scanning methodology are developed that provide reliable and sufficient data for the construction of equivalent emission models of PCB structures. The model of PCB emissions is developed that uses an array of equivalent dipoles deduced from magnetic near-field scans. Guidelines are proposed for setting the modelling configuration and parameters. The modelling accuracy can be improved by either improving the measurement efforts or using the mathematical regularization technique. An optimization procedure based on genetic algorithms is developed which addresses the optimal configuration of the model. For applications in closed environments, the equivalent model is extended to account for the interactions between the PCB and the enclosure. The extension comprises a dielectric layer and a ground plane which explicitly represent the necessary electromagnetic passive properties of a PCB. This is referred to as the dipole-dielectric-conducting plane (DDC) model and provides a completely general representation which can be incorporated into electromagnetic simulation or analysis tools. The modelling and characterization methodology provides a useful tool for efficient analysis of issues related to EMC design of systems with PCBs as regards predicting electromagnetic emissions in both free space and closed environment. The proposed method has significant advantages in tackling realistic problems because the equivalent models greatly reduce the computational costs and do no rely on the knowledge of detailed PCB structure.

Practical approach to model electric motors for electromagnetic interference and shaft voltage analysis

Abstract: This study presents a practical method to find a high-frequency model of AC machine in order to predict leakage current and shaft voltage A voltage-source inverter with hard switches generates pulse width modulated voltage with high dv/dt and common-mode voltage, which causes leakage current and shaft voltage due to stray capacitances in an electric motor At fundamental frequency (a few hundred hertz), an equivalent circuit of an electric motor consists of inductances and resistances without considering stray capacitances This study presents a practical approach in extracting high-frequency parameters of an electric motor for leakage current and shaft voltage analysis Input impedance (magnitude and phase values) of several configurations of an AC motor is measured using a network analyser All capacitive couplings between windings, stator and rotor are extracted based on theoretical analysis and measurement results Simulations are compared with test results to verify the proposed method and model

Practical approach to model electric motors for electromagnetic interference and shaft voltage analysis

Abstract: This study presents a practical method to find a high-frequency model of AC machine in order to predict leakage current and shaft voltage. A voltage-source inverter with hard switches generates pulse width modulated voltage with high dv/dt and common-mode voltage, which causes leakage current and shaft voltage due to stray capacitances in an electric motor. At fundamental frequency (a few hundred hertz), an equivalent circuit of an electric motor consists of inductances and resistances without considering stray capacitances. This study presents a practical approach in extracting high-frequency parameters of an electric motor for leakage current and shaft voltage analysis. Input impedance (magnitude and phase values) of several configurations of an AC motor is measured using a network analyser. All capacitive couplings between windings, stator and rotor are extracted based on theoretical analysis and measurement results. Simulations are compared with test results to verify the proposed method and model.

Fast Shielding Effectiveness Calculation of Metallic Enclosures With Apertures Using a Multiresolution Method of Moments Technique

Abstract: A multiresolution (MR) (wavelet) basis is employed in the method of moments (MoMs) analysis to achieve an efficient evaluation of the electromagnetic wave coupling inside metallic enclosures with arbitrary-shape openings. In this method, the electric field integral equation is solved on the surface of the enclosure discretized by triangular meshes. Using the MR meshing, different scales of the problem such as small apertures and narrow slots are represented directly into basis functions constructed by hierarchical sets of Rao-Wilton-Glisson expansion functions on a group of meshes yielded from subsequent refinements. As will be shown, the method results in highly sparse MoM matrices, which lead to fast convergence of iterative solvers. Hence, a remarkable reduction in the computational burden is achieved compared to the conventional RWG basis solution especially for the realistic enclosures with large number of apertures, used in the discipline of electromagnetic compatibility. Besides efficiency, the accuracy of the presented method is validated by a set of measurements conducted in an anechoic chamber.

Computation of Transient Electromagnetic Fields Due to Switching in High-Voltage Substations

Abstract: Switching operations of circuit breakers and disconnect switches radiate transient electromagnetic fields within high-voltage substations. The generated fields may interfere and disrupt normal operations of electronic equipment. Hence, the electromagnetic compatibility (EMC) of this electronic equipment has to be considered as early as the design stage of substation planning and operation. Also, microelectronics are being introduced into the substation environment and are located close to the switching devices in the switchyards more than ever before, often referred to as distributed electronics. Hence, there is the need to re-evaluate the substation environment for EMC assessment, accounting for these issues. This paper deals with the computation of transient electromagnetic fields due to switching within a typical high-voltage air-insulated substation (AIS) using the finite-difference time-domain (FDTD) method.

Electromagnetic Compatibility Uncertainty, Risk, and Margin Management

Abstract: A global methodology of electromagnetic compatibility (EMC) physics and risk analysis is presented in this paper. In order to manage the uncertainties of complex systems, the nine steps of the methodology based on statistics are described. A simple but representative EMC failure mode illustrates the methodology: the failure due to interference resulting from a lightning impact to the terminal equipment of a coaxial wire. Better cost/reliability ratios on the system constraints are achieved by controlling specifications by safety targets. In an industrial context, the main challenge of controlling margins during the development of complex systems is explained and achieved from predesign to advanced design.