Showing papers on "Electromagnetic compatibility published in 1999"

EMI emissions of modern PWM AC drives

Abstract: Electromagnetic interference (EMI) noise is defined as an unwanted electrical signal that produces undesirable effects in a control system, such as communication errors, degraded equipment performance and malfunction or nonoperation. This article provides a common understanding of the EMI issues and provides simple pre-installation and post-installation guidelines useful for all interested parries involved in the industry application of adjustable speed PWM invertor-fed AC motor drives.

Automotive Electronics Handbook

Abstract: Part I: Introduction. Part II: Sensors and Actuators. Pressure Sensors. Linear and Angle Position Sensors. Flow Sensors. Temperature, Heat, and Humidity Sensors. Exhaust Gas Sensors. Speed and Acceleration Sensors. Engine Knock Sensors. Engine Torque Sensors. Actuators. Part III: Control Systems. Automotive Microcontrollers. Engine Control. Transmission Control. Cruise Control. Braking Control. Traction Control. Stability Control. Suspension Control. Steering Control. Lighting, Wipers, Air Conditioning/Heating. Part IV: Displays and Information Systems. Instrument Panel Display Technologies. On- and Off-Board Diagnostics. Part V: Safety, Convenience, Entertainment, and Other Systems. Passenger Safety and Convenience. Remote Keyless Entry and Antitheft Systems. Entertainment Products. Multiplex Wiring Systems. Part VI: Electromagnetic Interference and Compatibility. Electromagnetic Standards and Interference. Electromagnetic Compatibility. Part VII: Emerging Technologies. Object Detection, Collision Warning, Collision Avoidance. Adaptive Cruise Control. Navigation Aids and Driver Information Systems. Intelligent Transportation Systems (ITS). Electric and Hybrid Vehicles. Noise Cancellation Systems. The Digital Vehicle.

Wide-load-range resonant converter supplying the SAE J-1773 electric vehicle inductive charging interface

Abstract: The recommended practice for electric vehicle battery charging using inductive coupling (SAE J-1773), published in January 1995 by the Society of Automotive Engineers, Inc., outlines values and tolerances for critical vehicle inlet parameters which must be considered when selecting a coupler driving topology. The inductive coupling vehicle inlet contains a significant discrete capacitive component in addition to low magnetizing and high leakage inductances. Driving the vehicle interface with a variable-frequency series-resonant power converter results in a four-element topology with many desirable features: unity transformer turns ratio; buck/boost voltage gain; current-source operation; monotonic power transfer characteristic over a wide load range; throttling capability down to no load; high-frequency operation; narrow modulation frequency range; use of zero-voltage-switched MOSFETs with slow integral diodes; high efficiency; inherent short-circuit protection; soft recovery of output rectifiers; and secondary d/spl nu//dt control and current waveshaping for the cable, coupler and vehicle inlet, resulting in enhanced electromagnetic compatibility. In this paper, characteristics of the topology are derived and analyzed using two methods. Firstly, the fundamental mode AC sine-wave approximation is extended to battery loads and provides a simple, yet insightful, analysis of the topology. A second method of analysis is based on the more accurate, but complex, time-based modal approach. Finally, typical experimental results verify the analysis of the topology presented in the paper.

On the coupling of an external electromagnetic field to a printed circuit board trace

Abstract: Compact analytical solutions are developed for the terminal responses of a printed circuit board (PCB) trace exposed to an external electromagnetic field in the frequency and time domain. The analysis based on transmission line theory in a scattered voltage formulation uses a quasi-TEM propagation model for the trace and the exact distribution of the external electric field within the air/dielectric medium for the excitation terms. From the general solutions obtained for arbitrary wave incidence and terminal impedances, several much simpler approximations are derived revealing the principal behavior and indicating the relevant parameters to minimize the coupling. Practical examples with a comparison of the different results are presented.

Broadband radio interferometer utilizing a sequential triggering technique for locating fast-moving electromagnetic sources emitted from lightning

Abstract: A broadband radio interferometer to investigate the location of fast-moving electromagnetic (EM) sources emitted from lightning discharges has been designed. A sequential triggering technique was applied to the system for recording the data of broadband electromagnetic pulses from 25 to 250 MHz. Once the electromagnetic pulse is detected and its amplitude exceeds a threshold level, the triggering circuit is turned on to record the waveform and get ready to acquire another pulse afterwards. This technique can overcome the limitation of the digitizer's memory due to such high digitization rate and very large bandwidth. We have implemented our system to locate and retrace fast-moving electromagnetic sources emitted from lightning discharges during a field experiment in Australia in summer 1997. As one of the results, a cloud-to-ground lightning discharge has been reconstructed in the two-spatial dimension and in time sequence.

Signal and noise measurement techniques using magnetic field probes

Abstract: Magnetic loops have long been used by EMC personnel to "sniff" out sources of emissions in circuits and equipment. Additional uses of such probes are presented here that can be very useful to both EMC personnel and circuit designers. Methods are shown for measuring crosstalk and inductive voltage drop along conductors, trace current paths on conducting planes, measure currents, and inject precisely controlled amounts of noise into a circuit. Data is presented in this paper to illustrate usage of some of these methods.

Electromagnetic compatibility issues in industrial equipment

Abstract: The aspects covered by the EMC regulations, in particular European Directive 89/336/EEC, are numerous and often complex. In this article, the authors have tried to summarize the standards recalled by the Directive for industrial and residential equipment and to emphasize some relevant measurement and design problems. The picture is surely vague and incomplete, but one point should be evident: EMC is a real problem and finding solutions which are technically suitable and economically competitive is today's challenge for design engineers.

Measurement of conducted electromagnetic emissions in PWM motor drive systems without the need for an LISN

Abstract: This paper presents a technique for measuring the conducted electromagnetic emissions produced by pulse-width modulated (PWM) inverter induction motor drive systems. The method does not require an artificial line-impedance stabilizing network (LISN) but does, however, allow the emission levels to be calculated as if an LISN were present. Testing can be performed when an LISN is either unavailable, prohibitively expensive, or impractical to include in the supply. This is often the case for large drive systems or for systems already installed in the field. A normal RF voltage probe and a spectrum analyzer are used to measure the spectra of the common-mode and differential-mode excitation sources due to the inverter switching. Line inductors for high-frequency (HF) isolation are required for some of the tests, but the cost and complexity of these compared to an LISN is low. Common-mode and differential-mode Thevenin equivalent circuits are then derived from measured impedances. The emissions for any defined supply impedance (including an LISN) can then be determined. A laboratory test on a 15 kW PWM drive system is carried out to verify the accuracy and effectiveness of the proposed method.

Reducing EMC problems through an electrical/optical interconnection technology

Abstract: A novel interconnection technology for printed circuit boards (PCBs) is proposed that has the potential to meet the high-performance requirements of future electronic equipment while at the same time, the electromagnetic compatibility (EMC) behavior will be improved significantly. The technology has a far-reaching compatibility with the existing printed circuit-board technology and the existing design and manufacturing processes of the electrical part do not need significant modifications. After a short description of the most important basic technologies for its realization, this paper focuses on a general approach for modeling the resulting hybrid electrical/optical interconnections containing integrated optical highly multimodal waveguides with manufacturing-caused rough surfaces. Especially the transient analysis is addressed in order to provide an efficient analysis methodology and algorithms for timing and signal integrity prediction necessary for designing and manufacturing high-speed electronic systems. The developed overall modeling strategy is explained and first available results are presented.

A probe for the measurement of electrical unbalance of networks and devices

Abstract: A probe has been developed to measure residual electrical unbalance of nominally balanced networks and devices. In the form described, it makes convenient the use of single-ended 50 /spl Omega/ instruments to measure electrical unbalance of wire pair networks and two-terminal devices. For electromagnetic compatibility (EMC) planning purposes, a knowledge of the electrical unbalance at signal interfaces in wire pair networks generally allows quantitative prediction of the conversion of wanted differential mode signals into unwanted radiated disturbances which can interfere with reception of radiocommunication services. The probe was first described to the CISPR in 1988. Since then, several other groups have also found it useful for measuring the electrical unbalance of telecommunication networks and devices. It has also been used to measure the differential mode signals and common mode disturbances at signal interfaces on balanced data signaling networks.

TEM waveguides for EMC measurements

Abstract: An overview of TEM waveguide electromagnetic compatibility (EMC) test facilities applicable to radiated emission and immunity measurements is given. Measurements of the field homogeneity in two TEM waveguides of different style are discussed. A statistical weighting of the measured electrical field is used to compare the results with standards requirements.

EMI/EMC issues in switch mode power supplies (SMPS)

Abstract: Power supplies have become the major factor in the deterioration of our electromagnetic environment. This paper aims to investigate, in general terms, the issue of electromagnetic interference (EMI) in switch mode power supplies (SMPS), including basic concepts and categories of EMC. The paper also points out the sources and causes of conducted emission in SMPS and the role of parasitic elements in propagation of EMI.

RF isolation using power islands in DC power bus design

Abstract: Power island structures are often employed for minimizing the propagation of high-frequency noise on DC power buses. The rationale is based on introducing a series impedance in the power plane to provide isolation of a noise source from the rest of the PCB design. The power island concept is investigated herein experimentally, to determine its noise mitigation attributes and limitations. A modeling approach that is suitable for arbitrary PCB island geometries including lumped SMT decoupling capacitors is also presented. The modeling and measurements indicate that island structures can achieve some degree of isolation under certain conditions.

Global time-domain full-wave analysis of microwave circuits involving highly nonlinear phenomena and EMC effects

Abstract: The global time-domain analysis of microwave circuits involving highly nonlinear phenomena such as injection locking and intermodulation, along with parasitic effects and electromagnetic compatibility (EMC) issues is presented in this paper. Employing the concept of equivalent sources, the device-wave interaction is characterized and incorporated into the finite-difference time-domain method. The investigation of nonlinear phenomena is accomplished by utilizing a large-signal device circuit model. Measured results are also provided for comparisons with simulated results. The applicability of this equivalent-source algorithm for investigating EMC effects is also demonstrated. A correspondence between simulated and measured EMC phenomenon indicates the usefulness of this algorithm in providing an effective tool for real world radio-frequency front-end circuit designs.

Analysis on loop area trace radiated emissions from decoupling capacitor placement on printed circuit boards

Abstract: This paper presents, with a solid conclusion, practical, hands-on applied EMC information for engineers that can be put to immediate use without relying on the mathematics of Maxwell's equations. An examination is made to determine if the physical placement of decoupling capacitors makes a significant difference in the development and propagation of radiated emissions from a printed circuit board (PCB) when used with actual, high-speed components. The focus is on what happens on both the top and bottom layers of a PCB, regardless of whether the board is single-sided, double-sided or multilayer. This paper complements existing research that investigates decoupling using simulation. Correlation between simulation and actual results is supported in this paper. A problem with simulation is that results calculated sometimes cannot take into consideration common-mode RF energy developed by components switching multiple outputs under maximum capacitive load, consuming a large amount of inrush current or impulse currents from switching cross-conduction. Common-mode energy cannot always be efficiently simulated at this time, thus causing the possibility of inaccurate assumptions regarding anticipated radiated emissions from a PCB layout. Behavioral models used for simulation are usually (theoretically) perfect and may not represent actual design parameters due to parasitics and other electromagnetic effects that cannot be easily calculated or anticipated. RF energy is developed due to digital components switching logic states. A voltage gradient on the power and ground planes between components causes common-mode EMI to be observed on interconnects and other radiating structures. Decoupling capacitors are provided to minimize voltage gradients, along with minimizing RF switching energy injected into the power distribution network and distributed throughout the entire PCB. The magnitude of radiated energy, related to decoupling capacitors is investigated in this paper, based on the physical location to digital components. In addition, common engineering problems in determining an optimal decoupling capacitor value are presented, with regard to both time and frequency domain analysis.

Hybrid space discretizing-integral equation methods for numerical modeling of transient interference

Abstract: The application of hybrid time-domain transmission line matrix (TLM)-integral equation (TLM-IE) methods is discussed. The hybrid TLM-IE methods are suited very well for the numerical modeling of the electromagnetic interaction between complex objects separated by large free-space regions. While the field inside the objects is modeled by the TLM method the electromagnetic interaction between the objects is described via Green's functions. The hybrid methods are applied to analyze the near-field coupling of two shielded enclosures. In a final discussion, the hybrid methods are compared with each other and with the pure TLM method, especially considering the computational time and storage requirement. Compared with the pure TLM method the hybrid methods require a considerably reduced computational effort.

Analysis of log periodic dipole array antennas for site validation and radiated emissions testing

Abstract: Log periodic dipole array (LPDA) antennas are one of the most widely used antenna types for normalized site attenuation (NSA) and radiated emission (RE) testing. A thorough understanding of the possible error sources associated with the calibration and application of LPDAs for EMC tests over a ground plane is essential for evaluating and minimizing measurement uncertainties. Systematic errors are present in the standard site calibration and NSA measurement, which are independent of random effects and equipment uncertainties. In an effort to determine the effects on NSA and RE testing, these errors are examined using a numerical moment-method model and measurements. Error contributions from mutual coupling between antenna and image, active phase center variation, radiation pattern, and cross-polarization effect are investigated.

Clock dithering for electromagnetic compliance using spread spectrum phase modulation

Abstract: As more electronic systems operate at higher frequencies and bandwidths, they tend to emit more electromagnetic interference (EMI). Due to lack of shielding, portable systems such as notebook computers have come under increasing pressure to comply with strict EMI emission regulations, such as FCC and CISPR. The data bus and the clock are major EMI sources because they conduct high currents and form large loops. This paper focuses on spreading the frequency-spectra of the clock and data signals to reduce their peak EMI emissions for EM compatibility. In a similar work, noise is intentionally injected onto a VCO control voltage in a clock PLL to achieve the effect of frequency modulation. In this case, the phase of the dithered clock varies unpredictably so mixing of both dithered and non-dithered clocks within the same system is avoided. In the proposed scheme, the phase difference between two arbitrary edges is limited within half a period. Hence, it is more practical in real system applications. Since it is implemented with a delay-locked loop (DLL), there are no PLL problems such as accumulated phase error, difficulties in designing stable loop filters, or area costs.

EMI-noise analysis under ASIC design environment

Abstract: Electromagnetic compatibility (EMC) has become more and more important in designing electronic systems. Although electromagnetic radiation itself mainly occurs from off-chip conductors, the ultimate noise source is in LSI chips. Among the noise distribution paths, the power-line conducting noise is the most significant source of electromagnetic interference (EMI)-noise caused by LSIs. This paper introduces an EMI-noise analysis method suitable for application-specific integrated circuit design environment especially focusing on the power-line con- ducting noise. Modeling method for power network and switching activity, simulation flow, and experimental results are presented. Experimental results show that our modeling methodology esti- mates capacitance values with sufficient accuracy and reproduces the relative differences in EMI-noise levels. Index Terms—ASIC, EMI-noise, LSI, simulation.

Electromagnetic field generator and method of operation

Abstract: An electromagnetic field generator and method of operation for ion beam deposition of magnetic thin-film materials is presented. A combination of open frame electromagnetic field generator elements provides precise control of magnetic field directionality. This control enables deposition of oriented magnetic films with minimal directionality error. The magnetic field direction may be oriented to enable the deposition of alternating layers of directionally oriented magnetic films. An open frame element reduces the weight of the electromagnetic field generator while truncated corners reduce diagonal clearance that may be required in a vacuum chamber. An open frame design also enables the electromagnetic field generator to surround and thus remain clear of the active deposition area; the electromagnetic field generator can thus be shielded from accumulation of sputtered material. Shielding from accumulation of sputter material reduces maintenance requirements.

Physical and technical bases of using ferromagnetic resonance in hexagonal ferrites for electromagnetic compatibility problems

Abstract: Frequency-selective measurement of microwave signal parameters based on application of gyromagnetic converters has proven advantageous for the research of microwave radiation over a wide spectrum (several octaves) in multisignal regime in microwave path and for the solution of a number of electromagnetic compatibility (EMC) problems. The measurement frequency band can be enlarged to millimeter-waves with application of monocrystal hexagonal ferrite resonators (HFR) having high internal magnetic fields. Millimeter-wave field interactions with the HFR having alternating resonance frequency are analyzed. This is useful for millimeter-wave signal modulation and demodulation. The analysis is based on the solution of magnetization vector motion equation of the uniaxial spherical HFR with time-varying bias magnetic field or angle of the HFR orientation (for modulation problem) and with amplitude-modulated microwave signal action (for demodulation problem). The novel principle of the HFR frequency-selective measuring system based on automodulation design is discussed.

PCB design techniques for lowest-cost EMC compliance. Part 1

Abstract: Application of good EMC (electromagnetic compatibility) practices to the design of printed circuit boards (PCBs) usually helps to achieve the EMC performance required of equipment and systems at much lower cost than alternative EMC measures at higher levels of integration, such as whole-product shielding. EMC design is a complex topic, but the proven best EMC practices for generalised PCB layout can be fairly simply stated and grouped into five techniques, which interact with each other to give dramatic improvements in EMC performance. This paper discusses the techniques of circuit segregation, interface suppression and the use of ground and power planes.

Conducting triangular chambers for EMC measurements

Abstract: Conducting rectangular chambers have been used extensively for electromagnetic compatibility (EMC) shielding and measurement applications. In this communication, conducting triangular chambers are investigated as an alternative structure for rectangular EMC reverberation chambers, which are becoming an increasingly important and powerful tool for both radiated immunity and emission tests. A prime consideration of designing such a system is the total possible number of modes inside the chamber. A new approach is introduced to obtain this parameter for three different triangular chambers. The initial study has demonstrated that triangular chambers may offer better performance in some cases than their rectangular counterparts.

Investigations into electromagnetic emissions from power system arcs

Abstract: Impulsive electromagnetic radiation can originate from many diverse sources in power systems when arcing occurs. The emission of radio wave energy in the form of a power system sferic in a similar way to lightning induced sferics is related to the non-linear properties of the plasma arc. This paper describes research work investigating the electromagnetic emissions in the very low frequency (VLF) and very high frequency (VHF) frequency bands from power system arcing events. Sources of power system sferics and the inducing mechanism are detailed. The characterisation of different types of power system arcing events recorded during experimentation are also discussed. The principles allowing power system arcing fault induced sferics to be discriminated from other impulsive noise sources and the location of the sferic's origin are outlined. Finally the practical implementation of a real-time fault monitoring system and recorded results are presented.

Electromagnetic radiation properties of a printed circuit board with a slot in the ground plane

Abstract: In this paper, the electromagnetic radiation simulation and measurement of a simplified printed circuit board (PCB) is described. The PCB is a microstrip line structure with a slot in the ground plane. The authors calculated scattering parameter S/sub 11/ and radiated emission by applying a full three-dimensional electromagnetic simulator based on the finite-element method. To verify the simulation results, a test PCB was designed and evaluated. The S/sub 11/ and both the near-field and far-field were measured and the experimental results were in agreement with that of the simulation. The authors have confirmed that the proposed method of placing a bypass capacitor across the slot is effective to suppress the radiated emission.

An improved model for the electromagnetic compatibility of all-dielectric self-supporting fiber-optic cable and high-voltage power lines

Abstract: It has become common for utilities to locate optical-fiber communication systems on their transmission line towers. One type of cable used for this purpose is all-dielectric self-supporting (ADSS) cable, which is usually located below the phase conductors. Cables of this type have failed because of exposure to high electric fields. In this paper, a model is developed which can be used to establish the conditions for failure-free operation of ADSS cable.

Wide-bandwidth multi-resolutional analysis of a surface-mounted PM synchronous machine

Abstract: Advances in power semiconductor devices have led to inverters with unprecedented voltage edge rates. This has decreased inverter switching losses and enabled the use of increasingly higher switching frequencies. However, faster edge rates and higher switching frequencies increase electromagnetic compatibility (EMC) problems, machine insulation stress, bearing currents, and other aspects of system design. Typical computer simulations used to design and evaluate proposed electric drive systems cannot be used to predict these high-frequency effects. A wide-bandwidth multiresolutional analysis that allows designers to anticipate and quantify high-frequency effects is detailed in this paper. The approach is specifically applied to permanent magnet synchronous machine drives, and is validated experimentally.

A subgridding scheme based on mesh nesting for the FDTD method

Abstract: A new and stable subgridding scheme based on mesh nesting is presented. This scheme is numerically stable, accurate, and easy to implement. The accuracy of the scheme is illustrated by examples of applications in electromagnetic compatibility (EMC). ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 211–214, 1999.

Mixed circuit/electromagnetic analysis of field coupling to high speed interconnects in inhomogenous medium

Abstract: An efficient method is presented for rigorous analysis of incident field coupling to high speed interconnects. The method is based on generating time domain equivalent sources from incoming fields through finite difference time domain analysis (FDTD) and incorporating them with a circuit level simulator such as SPICE. With this approach, it is possible to perform a circuit analysis of arbitrarily shaped structures which are exposed to external fields. Moreover, the proposed method overcomes the numerical stability problems of FDTD when coupled with nonlinear terminations.