Showing papers on "Electromagnetic compatibility published in 2009"

Electromagnetic Compatibility Engineering

Abstract: Praise for Noise Reduction Techniques IN electronic systems "Henry Ott has literally 'written the book' on the subject of EMC. . . . He not only knows the subject, but has the rare ability to communicate that knowledge to others." EE Times Electromagnetic Compatibility Engineering is a completely revised, expanded, and updated version of Henry Ott's popular book Noise Reduction Techniques in Electronic Systems. It reflects the most recent developments in the field of electromagnetic compatibility (EMC) and noise reductionand their practical applications to the design of analog and digital circuits in computer, home entertainment, medical, telecom, industrial process control, and automotive equipment, as well as military and aerospace systems. While maintaining and updating the core informationsuch as cabling, grounding, filtering, shielding, digital circuit grounding and layout, and ESDthat made the previous book such a wide success, this new book includes additional coverage of: Equipment/systems grounding Switching power supplies and variable-speed motor drives Digital circuit power distribution and decoupling PCB layout and stack-up Mixed-signal PCB layout RF and transient immunity Power line disturbances Precompliance EMC measurements New appendices on dipole antennae, the theory of partial inductance, and the ten most common EMC problems The concepts presented are applicable to analog and digital circuits operating from below audio frequencies to those in the GHz range. Throughout the book, an emphasis is placed on cost-effective EMC designs, with the amount and complexity of mathematics kept to the strictest minimum. Complemented with over 250 problems with answers, Electromagnetic Compatibility Engineering equips readers with the knowledge needed to design electronic equipment that is compatible with the electromagnetic environment and compliant with national and international EMC regulations. It is an essential resource for practicing engineers who face EMC and regulatory compliance issues and an ideal textbook for EE courses at the advanced undergraduate and graduate levels.

The Electromagnetic Compatibility of Integrated Circuits—Past, Present, and Future

Abstract: Throughout the decades of continuous advances in semiconductor technology, from the discrete devices of the late 1950s to today's billon-transistor system-on-chip, there have always been concerns about the ability of components to operate safely in an increasingly disruptive electromagnetic environment. This paper provides a nonexhaustive review of the research work conducted in the field of electromagnetic compatibility (EMC) at the IC level over the past 40 years. It also brings together a collection of information and trends in IC technology, in order to build a tentative roadmap for the EMC of ICs until the year 2020, with a focus on measurement methods and modeling approaches.

Overview of Recent Progress in Lightning Research and Lightning Protection

Abstract: This review paper, prepared for this second special issue on lightning of the IEEE Transactions on Electromagnetic Compatibility, summarizes major publications on lightning and lightning protection since the first special issue published in November 1998, i.e., during the last decade. The review is organized in the following five sections: lightning discharge-observations, lightning discharge-modeling, lightning occurrence characteristics/lightning locating systems, lightning electromagnetic pulse and lightning-induced effects, and protection against lightning-induced effects.

Design Guidelines for Interleaved Single-Phase Boost PFC Circuits

Abstract: This paper provides a comprehensive guideline for the design of a single-phase PFC targeting for minimal volume, as it is highly relevant for ultracompact integrated systems. It is shown, how different operation modes (continuous, boundary, and discontinuous conduction mode) may influence the design and consequently the achieved power density. Furthermore, the effect of interleaving of several boost stages is analyzed as a measure for compactness increase. Finally, the selection of the appropriate switching frequency in order to achieve an overall optimized system is discussed. In this way, the design of the crucial components is carried out, namely, the boost inductor, including a volume optimization through a thermal connection to the heat sink; the output capacitor considering the rms current stress; and the input filter, which is designed for compliance with high-frequency electromagnetic compatibility standards, taking into account the quasi-peak detection measurement of the test receiver equipment.

Microwave Analog Real-Time Spectrum Analyzer (RTSA) Based on the Spectral–Spatial Decomposition Property of Leaky-Wave Structures

Abstract: A novel analog real-time spectrum analyzer (RTSA) for the analysis of complex nonstationary signals (such as radar, security and instrumentation, and electromagnetic interference/compatibility signals) is presented, demonstrated, and characterized. This RTSA exploits the space-frequency mapping (spectral-spatial decomposition) property of the composite right/left-handed (CRLH) leaky-wave antenna (LWA) to generate the real-time spectrograms of arbitrary testing signals. Compared to digital RTSAs, it exhibits the advantages of instantaneous acquisition, low computational cost, frequency scalability, and broadband or ultra-wideband operation. The system is demonstrated both theoretically by a commercial full-wave simulator and an efficient Green's function approach and experimentally by a parallel-waveguide prototype including a metal-insulator-metal CRLH LWA, 16 patch antenna probe detectors circularly arranged around the LWA, and a digital oscilloscope performing analog/digital conversion and time-domain acquisition before the postprocessing and displaying of the spectrogram. The system is tested for a large diversity of nonstationary signals and generates, in all cases, spectrograms that are in excellent agreement with theoretical predictions. The fundamental tradeoff between time and frequency resolutions inherent to all RTSA systems is also discussed, and an interchangeable multi-CRLH LWA solution is proposed to handle signals with different time durations.

Modeling of Grounding Electrodes Under Lightning Currents

Abstract: More precise modeling of the dynamic performance of grounding electrodes under lightning currents must include both the time-dependent nonlinear soil ionization and the frequency-dependent phenomena. These phenomena might have mutually opposing effects since the soil ionization effectively improves, while frequency-dependent inductive behavior impairs, the grounding performance. Modern approaches that take into account both phenomena are based on circuit theory that does not allow for accurate analysis of high-frequency behavior. This paper aims to further improve the understanding of the dynamic behavior of grounding electrodes under lightning currents by focusing on the following aspects: analyzing the validity domains of popular modeling approaches, based on circuit, transmission line, and electromagnetic theory; providing parametric analysis that takes into account both the propagation and soil ionization effects; analyzing simple formulas for surge characteristics; and comparing the modeling with experimental data. A model and a simple formula that combine the electromagnetic approach, suitable for high-frequency analysis, with the method that accounts for the soil ionization effects, recommended by the International Council on Large Electric Systems (CIGRE) and the IEEE Working Groups, are used for the parametric analysis. Both the model and the simple formula are verified by comparison with experimental results available in the literature.

Comprehensive Design and Optimization of a High-Power-Density Single-Phase Boost PFC

Abstract: The design of a single-phase boost power-factor-correction (PFC) circuit is associated with a large variety of considerations, such as the following questions. Which operation mode should be selected (e.g., continuous or discontinuous operation)? How many interleaved boost cells are advantageous? Which switching frequency should be selected? What is the optimum number of EMI input filter stages? Which semiconductor technology should be chosen? All these issues have a significant influence on the converter efficiency and power density. In this paper, the aforementioned questions are addressed for exemplary specifications of the PFC (300-W output power, 400-V output voltage, and 230-V mains voltage), whereby the focus in the design is mainly put on very high power density. As a result, different design points are identified and comparatively evaluated. By considering different aspects such as volume, losses, capacitor lifetime, and also cost issues (e.g., by additional current sensors or expensive silicon carbide devices), a dual-interleaved PFC operated in discontinuous conduction mode at 200 kHz is selected. With an experimental prototype, a superior power density of 5.5 kW/L and a system efficiency of 96.4% are achieved, which is close to the values predicted by the design procedure. Furthermore, measurements verify a near-unity power factor (PF = 99.7%) and the compliance with electromagnetic compatibility conducted noise emission standards. Finally, it is investigated to which extent the power density could be further increased by an integration of the input filter in the PCB.

Impact of EMC Filters on the Power Density of Modern Three-Phase PWM Converters

Abstract: Electromagnetic compatibility (EMC) filters are typically included in offline power converters, controlling electromagnetic emissions, but adding volume to power electronic systems. During the last decades, one of the main objectives of the power electronics industry has been the increase of the power density. Thus, it is reasonable to analyze how filters affect power density values, imposing limits or ldquobarriersrdquo to it. The impact of the EMC filters on the overall volume of three-phase pulsewidth modulation (PWM) converters is studied here for converters in the range of 5-10 kW. An analytical procedure based on the volume minimization of the EMC filters is proposed to estimate the total filter volume as function of the converters' rated power and switching frequency. With this, the minimum volume for EMC filters that allow the converters to comply with EMC standards regarding conducted emissions can be estimated and volume limitations identified. A discussion about the limits of power density for the considered three-phase PWM converters for state-of-the-art power semiconductors is performed, and optimum switching frequencies are identified. An experimental verification is carried out, which validates the achieved results.

EMC Issues in High-Power Grid-Connected Photovoltaic Plants

Abstract: This paper outlines the main electromagnetic compatibility issues frequently encountered in high-power grid-connected photovoltaic (PV) systems, and proposes several guidelines that allow to obtain an effective and highly efficient layout of the plant. At first, with reference to a 1-MWp PV plant of Sorgenia Solar, Italy, the paper focuses on the peculiar aspects concerning the radio-frequency behavior of a large-size PV plant: the great extent of the direct-current cabling, the capacitance toward earth of the PV source, the common-mode (CM) disturbance generated by inverters, the galvanic isolation ensured by dedicated low-voltage power transformers, and the presence of resonant circuits for CM leakage currents. The dominant electromagnetic phenomena and coupling mechanisms are pointed out by means of an equivalent circuit and through measurements. In the light of the matured experience, several guidelines are proposed and a new reliable layout is implemented on a second 1-MWp PV plant. New measurements confirm the validity of the proposed design strategy.

Increasing Voltage Utilization in Split-Link, Four-Wire Inverters

Abstract: Three-phase four-wire inverters, with either three-leg or four-leg topology, are useful for interfacing distributed generation to networks of unbalanced loads, but neither of the available circuit topologies is ideal. The split-link three-leg topology (with six switches) suffers from poor DC voltage utilization compared with the four-leg topology (with eight switches). The four-leg topology has an electromagnetic compatibility (EMC) difficulty because it imposes large-amplitude high-frequency voltages between the DC-link busbars and ground. To obtain both good dc voltage utilization and good EMC performance, it is proposed to use a split-link inverter with an active balancing circuit (also eight switches). The balancing circuit is used to modulate the DC busbar offset voltage to make better use of the available DC-link voltage. The optimum voltage term is established to be a third harmonic term, and the DC voltage utilization is improved. A deadbeat controller supplemented with a repetitive controller is designed to give good tracking and good disturbance rejection for the busbar offset voltage. System performance is studied through an experimental test rig.

A Fast Stroud-Based Collocation Method for Statistically Characterizing EMI/EMC Phenomena on Complex Platforms

Abstract: A fast stochastic collocation method for statistically characterizing electromagnetic interference and compatibility (EMI/EMC) phenomena on electrically large and loaded platforms is presented. Uncertainties in electromagnetic excitations and/or system geometries and configurations are parameterized in terms of random variables having normal or beta probability density functions. A fast time-domain integral-equation-based field-cable-circuit simulator is used to perform deterministic EMI/EMC simulations for excitations and/or system geometries and configurations specified by Stroud integration rules. Outputs of these simulations then are processed to compute averages and standard deviations of pertinent observables. The proposed Stroud-based collocation method requires far fewer deterministic simulations than Monte Carlo or tensor-product integrators. To demonstrate the accuracy, efficiency, and practicality of the proposed method, it is used to statistically characterize coupled voltages at the feed pins of cable-interconnected and shielded computer cards as well as the terminals of cables situated inside the bay of an airplane cockpit.

Common-Mode Emissions Measurements and Simulation in Variable-Speed Drive Systems

Abstract: In order to efficiently reduce electromagnetic interference emissions, especially common-mode (CM)-conducted noise emissions, which are the most disturbing in any variable-speed drive systems, the understanding of behavior and the knowledge of propagation path of parasitic currents in the system are essential. In this paper, a simple CM disturbances modeling is proposed to predict or estimate the CM noise currents. The modeling principle is based on specific experimental characterizations and the modeling of the complete CM circuit considered as a chain of quadripolar matrices. Each part of the system is represented by a two-port network associated in cascade using matrix [T]. The comparison between calculations and experiments in a variable-speed drive system effectively confirms the validity of the proposed approach. Parametric studies carried out herein using this valid model will show the way in which CM currents could be reduced or eliminated in a considered existing system.

Analysis of electromagnetic force in wire-EDM

Abstract: This paper clarifies the mechanism of how electromagnetic force applied to the wire electrode in wire electrical discharge machining (wire-EDM) is generated. This electromagnetic force is caused not only by DC component but also by AC components of the discharge current supplied to the wire. We therefore developed and used a two-dimensional finite element method (FEM) program to analyze the electromagnetic field taking into account electromagnetic induction. Assuming that trapezoidal pulse current is supplied to the wire, distributions of the current density and magnetic flux density were analyzed and changes in the electromagnetic force applied to the wire were calculated. Wire movement when the electromagnetic force alone was applied to the wire was also calculated. The calculated wire movement agreed with the measured wire movement when pulse current actually used in WEDM was supplied to the wire, clarifying the mechanism of electromagnetic force generation.

An Experimental Study of Common- and Differential-Mode Active EMI Filter Compensation Characteristics

Abstract: Most reported compensation schemes for active electromagnetic interference filters (AEFs) use either voltage canceling or current canceling to deal with high-frequency noise interference. The purpose of this paper is to investigate the compensation characteristics of these two kinds of AEFs for different types of noise sources, i.e., common mode (CM) and differential mode (DM) noise source. This is examined by experimental identification and theoretical analysis of the insertion losses of AEF with voltage- or current-cancellation scheme. It is demonstrated that current-canceling AEFs are effective in eliminating high-impedance CM noise, while voltage-canceling AEFs are good compensation solutions for low-impedance DM noise. The results reported in the paper enable the choice of optimized compensation schemes, using the aforementioned indicated aspects.

“Black box” EMC model for power electronics converter

Abstract: The generalization of switched mode power conversion in embedded networks generates new problems at system level: the prediction of ElectroMagnetic Compatibility behaviour of the complete system. In order to forecast the conducted emissions in the power lines, compact models of the power converters are needed. This paper aims to propose a generic black box model for converters connected to an embedded network. The methodology for identifying the model parameters will be given, as well as the model validation.

Network-Friendly Low-Switching-Frequency Multipulse High-Power Three-Level PWM Rectifier

Abstract: High-power converters for regenerative drives and distributed generation need a network-friendly operation, low harmonic conductive electromagnetic emission for low electromagnetic interference and high electromagnetic compatibility reaching high reliability and performance. Nevertheless, the converters must be controlled with low switching frequency in order to reduce the commutation losses. These two requirements can be satisfied if an optimal modulation strategy is used. The selective harmonic elimination (SHE) is one of the low-switching-frequency strategies most used today. However, this strategy only eliminates a reduced set of harmonic components from the input current. This paper presents a novel optimal modulation strategy whose objective is to reduce the total harmonic distortion of the input current. Six- and twelve-pulse three-level neutral-point-clamped pulsewidth modulation rectifiers are used in order to implement both modulation techniques. The results confirm the advantages of the proposed strategy, namely, less input current distortion and remarkable reduction of higher order harmonics compared with the SHE method, while keeping a low-switching behavior.

Design of Grid-Side Electromagnetic Interference Filters in AC Motor Drives With Motor-Side Common Mode Active Compensation

Abstract: The aim of this paper is to analyze how the introduction of a motor-side common mode (CM) active filter, in a power drive system, influences the CM disturbance propagation. A circuit model of the whole drive, including the active filter, is used as an investigation tool. The accuracy of all simulated results is validated by experimental measurements. Both the electromagnetic interference (EMI) toward the grid and the internal CM disturbance propagation are analyzed. These phenomena are compared when the power drive system is operated both with and without the active filter at the inverter output. An additional effect of the motor-side CM active filter is a slight reduction of EMI toward the grid at lower frequencies. This condition allows a reduction in the size of the power grid CM EMI filter necessary to achieve electromagnetic compatibility requirements compliance for the drive.

Performances of UWB Wheeler Cap and Reverberation Chamber to Carry Out Efficiency Measurements of Narrowband Antennas

Abstract: This letter deals with using ultrawideband (UWB) Wheeler Cap (UWB WCap) and reverberation chamber (RC) to measure efficiencies of narrowband antennas. This first testbed designed for very broadband systems can also be accurate for narrowband antennas. The second one, first designed for electromagnetic compatibility (EMC) measurements, offers advantages to measure antenna efficiency. Results are given to assess uncertainty and accuracy of both measurement means.

Synthesis of Equivalent 3-D Models from Near Field Measurements— Application to the EMC of Power Printed Circuit Boards

Abstract: The paper presents an original methodology to characterize electromagnetic disturbances radiated from power electronic devices. The approach is based on the substitution of an equivalent set of elemental dipoles for the real system; this set radiates the same near-field. The dipoles are determined from a near-field cartography of the fields obtained with a measurement bench. The parameters of the dipoles are determined by solving an inverse problem. The efficiency of the approach is demonstrated for a 3-D case and for a practical dc-dc converter.

Real-time distributed monitoring of electromagnetic pollution in urban environments

Abstract: In the last two decades, the wide diffusion of mobile phones and wireless technologies has brought many advantages in professional activities as well as in everyday life. In general, mobile communication networks are constituted by a limited number of base stations. The spatial distribution of the field radiated from base stations turns out to be non-uniform with variations both in time and space that can exceed the normative limits of electromagnetic emissions. In order to real-time and in a long-term monitor the electromagnetic emissions, an innovative low cost solution based on a wireless sensor network (WSN) is presented in this paper. Such a network consists of spatially distributed and wirelessly connected autonomous devices (called nodes) that use suitable sensor to cooperatively collect physical quantities. The proposed solution considers the deployment of a set of WSN nodes, equipped with a broadband field probe, to monitor the level of the electromagnetic radiation in a distributed and real-time fashion.

A Theoretical Feasibility Study of a Source Stirring Reverberation Chamber

Abstract: A novel theoretical feasibility study to reverberate a large metallic chamber is proposed. The method is based on the displacement of a radiating antenna inside the chamber, and the reverberating effect is obtained by coupling the antenna current in different ways with the cavity modes. This technique eliminates mechanical rotating paddles inside the chamber and offers the advantage of a continuous-wave operation compared with the frequency stirring method. The reverberating characteristics of the proposed technique are evaluated by calculating the field statistics. The analyzed situation concerns a real antenna, and its radiation into the reverberation chamber is modeled using Green's function of cavity. The numerical problem is solved by the method of moment. The model has been tested and is able to rigorously characterize the reverberating environment for the design and optimization of antenna configurations to be addressed in future studies.

Power Quality and EMC in Smart Grid

Abstract: Smart Grid is increasingly seen as a means to facilitate climate friendly renewable energy sources (renewables) and to enable efficient use of electricity. For example, modern electrical networks can link wind- and solar power with electric cars. A consequence of Smart Grid is a drastic increase in use of electronics in the power system. This makes the satisfactory function of electrical and electronic equipment vital for realization of a robust Smart Grid. This paper focuses on the satisfactory function of equipment for Smart Grid with respect to electromagnetic disturbances, i.e. EMC — Electromagnetic Compatibility including Power Quality. Finally, a framework for the apportioning of responsibilities between network operators and the parties being responsible for the connection of equipment is proposed.

Dual-Boost Single-Phase PFC Input Current Control Based on Output Current Sensing

Abstract: This paper presents a new current control method for dual-boost single-phase power-factor-correction (PFC) converters. A dual-boost PFC converter is more efficient than the conventional boost PFC converter by virtue of the elimination of one semiconductor device in the main current path, but is more difficult to control using the existing PFC control method due to the need to sense ac input current and voltage. The proposed current control method is based on sensing of the dc output current, which can be easily accomplished by using a sensing resistor inserted on the negative rail of the dc output. A new pulsewidth-modulation-based multiplier circuit is also developed as a more robust and cost-effective alternative to linear analog multiplier design or mixed-signal implementation. Control characteristics and performance of the new method are analyzed using averaged models and verified by measurement results from a 500 W prototype. Operation of the converter with both 60 and 400 Hz line is reported to demonstrate its performance for both terrestrial and airborne applications. Conducted electromagnetic interference measurements of the converter are also presented.

Reduction of EMI in AC Drives Through Dithering Within Limited Switching Frequency Range

Abstract: In this paper, a method is presented to reduce electromagnetic (EM) emissions in AC drives. This method is applicable to many AC drives. It is proposed to dither the switching frequency of the power devices of an inverter in a pseudorandom way to spread out the emitted RF energy over a larger frequency range. The proposed method requires only software changes. Practical constraints to implement the frequency dithering approach are discussed. Simulation and measurement results show an improvement of more than 10 dB. The proposed method also converts specific spikes in the long-wave range from narrowband to broadband noise, which results in less stringent EM emission requirements for many applications.

Simulation of Electromagnetic Transients of the Bus Bar in Substation by the Time-Domain Finite-Element Method

Abstract: In order to analyze the electromagnetic interference (EMI) generated from the aerial bus bars in substation, the transient electromagnetic wave process on the bus bars is calculated by using the time-domain finite-element (TDFE) method. The TDFE method is preferable to both the commonly used finite-difference time-domain (FDTD) method, which has difficulties in dealing with the multiconductor transmission lines (MTLs) with lumped parameter networks, and the universal software electromagnetic transient program (EMTP), which is not effective for the calculation of the whole electromagnetic wave processes along the MTLs. The feasibility and efficiency of the proposed TDFE method have been demonstrated by comparing the numerical results with experimental measurements. Furthermore, we have performed a successful case study on the numerical prediction of the EMI in the secondary cable in substation by using the TDFE method.

Characterization of the Evolution of IC Emissions After Accelerated Aging

Abstract: With the evolving technological development of integrated circuits, ensuring electromagnetic compatibility (EMC) is becoming a serious challenge for electronic circuit and system manufacturers. Although electronic components must pass a set of EMC tests to ensure safe operations, the evolution of EMC over time is not characterized and cannot be accurately forecast. This paper presents an original study about the consequences of the aging of circuits on electromagnetic emissions. Different types of standard applicative and accelerated life tests are applied on a mixed power circuit dedicated to automotive applications. Its conducted emissions are measured before and after these tests, showing variations in EMC performance. Comparisons between each type of aging procedure show that the emission level of the circuit under test is differently affected.

Reduction of conducted EMC using busbar stray elements

Abstract: Busbar structures must first achieve the principal function of a low inductive, multiport interconnection. Therefore, large sheets, very close to each other are used. An interesting issue is to use the inherent capacitive effects of busbars for achieving an integrated EMI filter function. However, this may not cause any inductance degradation. Busbar topology including the ground potential brings some EMC filtering capability. A multilayer topology is proposed to both increase the capacitances of interest and decrease the stray inductance. This has been validated using simulations and experimental results. Finally, multipurpose busbars (Electrical link, Mechanical support, thermal dissipator, EMC filter) may be one of the future key points of Power Electronics integration.

Study on planar busbar regarding stray inductance minimization and oscillation suppression for high power converter

Abstract: Planar busbars have played a significant role in reducing the parasitic/stray inductance in modern high power converters, which is caused by physical current path loop from the IGBT to DC capacitors. Consequently, it may lead to such problems as non-ideal converter operation, over-voltages, voltage drop, current unbalance and resonance with DC capacitors as well as snubber capacitors, especially applied with active power filters (APF) usually with a wide range of current frequency. This paper presents a new physical structure for a voltage source inverter applied in 380V/400A APF with low inductance and oscillation busbar structure, in which the design considerations and analysis are given. The experimental and simulation results show that it obtained very low stray inductance and had good electromagnetic compatibility (EMC) performance.

New Alternative Passive Networks to Improve the Range Output Voltage Regulation of the PWM Inverters

Abstract: This paper presents different topologies of buck-boost converters with passive input networks that have alternative topologies; this is known in the literature as a Z-source inverter. Alternative passive networks were named by the authors as T-inverters; these improve output voltage regulation of the PWM inverters. T-inverter has fewer reactive components in comparison to conventional Z-source inverter. The most significant advantage of the T-inverter is its use of a common voltage source of the passive arrangement. This solves many problems involving electromagnetic compatibility which are present in the Z-source inverter. Experimental results for the T-inverter are in agreement with theoretical and simulated predictions.