Showing papers on "Electromagnetic compatibility published in 2014"

3-D Electromagnetic Modeling of Parasitics and Mutual Coupling in EMI Filters

Abstract: The electromagnetic compatibility (EMC) analysis of electromagnetic interference (EMI) filter circuits using 3-D numerical modeling by the partial element equivalent circuit (PEEC) method represents the central topic of this paper. The PEEC-based modeling method is introduced as a useful tool for the prediction of the high frequency performance of EMI input filters, which is affected by PCB component placement and self- and mutual-parasitic effects. Since the measuring of all these effects is rather difficult and time consuming, the modeling and simulation approach represents a valuable design aid before building the final hardware prototypes. The parasitic cancellation techniques proposed in the literature are modeled by the developed PEEC-boundary integral method (PEEC-BIM) and then verified by the transfer function and impedance measurements of the L-C and C-L-C filter circuits. Good agreement between the PEEC-BIM simulation and the measurements is achieved in a wide frequency range. The PEEC-BIM method is implemented in an EMC simulation tool GeckoEMC. The main task of the presented research is the exploration of building an EMC modeling environment for virtual prototyping of EMI input filters and power converter systems.

An Improved Layout Strategy for Common-Mode EMI Suppression Applicable to High-Frequency Planar Transformers in High-Power DC/DC Converters Used for Electric Vehicles

Abstract: Presently, there is an immense impetus in the automotive industry to develop plug-in electric vehicles (PIEVs) to reverse the ever increasing green house gas emissions from fossil fuels and depleting fossil fuel resources. High-frequency ac-dc converters with an isolated output are one of the essential building blocks for transferring power from utility mains to the traction battery packs which store energy for propelling the EV. Generally, the ac/dc converters used in EVs include a PFC stage at the input side and an isolated dc/dc converter at the battery side. Due to the switching nature of the converter, electromagnetic compatibility (EMC) of these converters is an essential requirement, to ensure not only its own operation but also the safe and secure operation of surrounding electrical equipment. EVs possess a lot of sophisticated electronic circuits in the vicinity of the battery charging power converters. Thus, strict EMC standards of the on-board power converters must be met according to the CISPR 12 or SAEJ551/5 relevant EMC standards. Conventional passive filters used for EMI mitigation in power converters, comes at the expense of cost, size and weight, power losses, and printed circuit board real estate. In this paper, an electromagnetic interference (EMI) filter embedded into the main high-frequency planar transformer used in the dc/dc converter is proposed as a very cost-effective and efficient solution for EVs. The proposed structure is able to significantly suppress the common-mode (CM) EMI noise generated in the dc/dc converter. Experimental results have been obtained from a 3-kW prototype in order to prove the feasibility and performance of the proposed EMI filter. The results show that the proposed embedded EMI filter can effectively suppress the CM noise particularly for high switching frequency power converters. The proposed structure can be a very simple and cost-effective EMI filtering solution for future PIEVs.

Modeling of a Buck Converter With a SiC JFET to Predict EMC Conducted Emissions

Abstract: The reduced switching times of silicon carbide (SiC) components compared to Si components in similar conditions are a great advantage from the point of view of efficiency, but, due to the high dv/dt and di/dt, conducted electromagnetic emissions are increased. Therefore, the availability of a method which can predict these emissions is increasingly necessary. To the best of the authors' knowledge, a model that can predict differential mode as well as common mode for a converter including sic devices has not yet been published. the novelty of the work presented here is the integration of different modeling approaches to form a circuit model of a SiC-based buck dc-dc converter working in frequency range from 40 Hz to 30 MHz. A modeling approach of the passive parts of the converter is presented. Then, the model obtained is used in simulations to predict the drain-to-source voltage and the drain current for the JFET. Conducted emissions received by the line impedance stabilization network are also computed. Simulation results are compared to measurements for different duty cycles and different gate resistors in the time and frequency domains. A good agreement is obtained. In the frequency domain, in all cases, differences are less than 5 dBμV up to 30 MHz excepted in the JFET source current.

3-D Electromagnetic Modeling of EMI Input Filters

Abstract: In this paper, a novel 3-D electromagnetic modeling approach which enables electromagnetic compatibility (EMC) analysis of power converter systems in an accurate and computationally efficient way is presented. The 3-D electromagnetic modeling approach, implemented in the EMC simulation tool GeckoEMC, is based on two numerical techniques, the partial element equivalent circuit method and the boundary integral method (PEEC-BIM). The developed PEEC-BIM coupled method enables comprehensive EMC analysis taking into account different effects of the PCB layout, self-parasitics, mutual coupling, shielding, etc., which in turn provides a detailed insight into the electromagnetic behavior of power electronic systems in advance to the implementation of hardware prototypes. The modeling features of the GeckoEMC simulation tool for virtual design of electromagnetic interference (EMI) filters and power converters is demonstrated on the examples of a single-phase two-stage EMI filter and a practical EMI filter for a single-phase PFC input stage. Good agreement between the PEEC-BIM simulation and the small signal transfer function measurement results is achieved over a wide frequency range, from dc up to 30 MHz. The EMC simulation environment enables a step-by-step EMC analysis distinguishing the impact of various electromagnetic effects on the EMI filter performance and allowing an optimal EMI filter design.

Applications of the FDTD Method to Lightning Electromagnetic Pulse and Surge Simulations

Abstract: Electromagnetic computation methods (ECMs) have been widely used in analyzing lightning electromagnetic pulses (LEMPs) and lightning-caused surges in various systems. One of the advantages of ECMs, in comparison with circuit simulation methods, is that they allow a self-consistent full-wave solution for both the transient current distribution in a 3-D conductor system and resultant electromagnetic fields, although they are computationally expensive. Among ECMs, the finite-difference time-domain (FDTD) method for solving Maxwell's equations has been most frequently used in LEMP and surge simulations. In this paper, we review applications of the FDTD method to LEMP and surge simulations, including 1) lightning electromagnetic fields at close and far distances, 2) lightning surges on overhead power transmission line conductors and towers, 3) lightning surges on overhead distribution and telecommunication lines, 4) lightning electromagnetic environment in power substations, 5) lightning surges in wind-turbine-generator towers, 6) lightning surges in photovoltaic (PV) arrays, 7) lightning electromagnetic environment in electric vehicles (EVs), 8) lightning electromagnetic environment in airborne vehicles, 9) lightning surges and electromagnetic environment in buildings, and 10) surges on grounding electrodes.

Single Shot and Vectorial Characterization of Intense Electric Field in Various Environments With Pigtailed Electrooptic Probe

Abstract: In this paper we illustrate the ability of electrooptic sensors to perform electric (E)-field vectorial measurements. Thanks to their frequency response spreading over nine decades and to their measurement dynamics reaching 120 dB, these sensors are of high interest for some applications (near field mapping, energy line monitoring, electromagnetic compatibility, and so on). Furthermore, due to their fully dielectric structure and millimetric size, almost no perturbation is induced on the E-field to be measured, even in the near field region. This paper is focused on high-intensity pulsed E-field characterization in different environments such as air, water (bioelectromagnetism applications), or plasmas ( in situ assessment of the E-field associated to an electric discharge and to the induced plasma). The use of such a technology for electrical equipment and energy line monitoring is also investigated.

Design and Implementation of Integrated Common Mode Capacitors for SiC-JFET Inverters

Abstract: This paper deals with the issue of electromagnetic interference (EMI) in SiC-JFET inverter power modules, and proposes a solution to limit conducted emissions at high frequencies. SiC-JFET inverters can achieve very fast switching, thereby reducing commutation losses, at the cost of a high level of EMI. In order to limit conducted EMI emissions, it is proposed to integrate small-value common-mode (CM) capacitors, directly into the power module. High-frequency noise, which is usually difficult to filter, is then contained within the module, thus keeping it far from the external network. This approach is in line with the current trend toward the integration of various functions (such as protection, sensors or drivers) around power devices in modern power modules. To demonstrate this concept, the resulting CM noise was investigated, and compared with a standard configuration. Simulations were used to design the integrated capacitors, and measurements were carried out on an experimental SiC-JFET half-bridge structure. A significant reduction was achieved in the experimentally observed CM conducted emissions, with a very minor influence on the switching waveforms, losses, and overall size of the system. The benefits and limitations of this design are discussed for the case of mid-power range inverters for aircraft applications.

Electromagnetic Gun Technology and Its Development

Abstract: In order to provide a reference for further development of electromagnetic gun technology, after reviewing the achievement and application prospects of electromagnetic gun, we introduced the research status of electromagnetic gun and its related key technology. In view of the characteristics of electricity, the advantages and disadvantages of electromagnetic gun technology based on the energy use are analyzed. It is pointed out that the electromagnetic gun is the inevitable development trend of launch technology. Although the principle of electromagnetic lunch(EML) is simple, the EML technology is of extremely high complexity due to involving many abnormal extreme conditions. The understanding of relevant laws and phenomena is also very limited. Consequently, the emitter life problem is the precondition of electromagnetic gun to application, and the miniaturization of the power supply will be the key problem for quite some time in the field of electromagnetic gun technology application. It is necessary to have a specific focus on the key technology in order to develop electromagnetic launch technology rapidly and promote the application of electromagnetic gun.

EMI Reduction in DC-Fed Electric Drives by Active Common-Mode Compensator

Abstract: A novel common-mode (CM) EMI active filter for dc-fed motor drives is proposed. The active filter performs both the compensation of the CM voltage at the motor input and the mitigation of the leakage high-frequency CM currents, thus increasing the drive reliability and the vehicle electromagnetic compatibility (EMC). The filter scheme is based on a voltage feedback action and also includes a feed-forward action by exploiting a suitably estimated CM current. An optimized design of the CM voltage detection/injection systems is implemented. Moreover, the active filter is supplied by a smaller voltage than the dc link value; this permits a more performing amplifier to be used. The active filter behavior is analyzed theoretically and its performance is assessed by experiments. The realized prototype shows a good efficiency and compactness.

Time-Domain-Based Assessment of Data Transmission Error Probability in Smart Grids With Electromagnetic Interference

Abstract: Reliable operation of the smart grid requires assurance of the electromagnetic compatibility of sensitive smart metering systems and power electronic converters, which introduce high-level electromagnetic interference. As it has been experimentally shown, currently available, normalized, and frequency domain tests are ineffective for the evaluation of data transmission error hazards. The mathematical time-domain model proposed in this paper enables assessment of the probability of errors occurring in a given transmission signal for known interference parameters. The validity of the model and its practical applicability have been experimentally verified.

Transfer Function Method for Predicting the Emissions in a CISPR-25 Test-Setup

Abstract: The CISPR-25 standard is used in the automotive industry to characterize the electromagnetic radiation of electronic components. The setup is comprised of an electronic device, a cable harness, a metallic table, and an antenna. Dimensions stretch from a couple of meters for the setup to fractions of a millimeter for printed circuit board features. Numerical prediction of radiated emissions (RE) is of great usefulness for prediction of potential electromagnetic compatibility nonconformities in the early design process, but extremely difficult to be done for this setup as a whole. In this paper, we demonstrate how RE can efficiently be computed based on a setup as commonly used to model conducted emissions only, i.e., electric control unit and harness on infinite-ground plane. Applying Huygens principle and using it to generate a fixed transfer function between a particularly chosen Huygens surface and the antenna, we arrive at a novel computing scheme for RE. The scheme is applied for the antenna model and antenna factor-based calculations and demonstrates agreement with measurements within 5 dB range.

Study of the electromagnetic compatibility of local area networks under the action of nanosecond electromagnetic disturbances

Abstract: The experimental test bench has been developed to perform the quantitative studies of the electromagnetic compatibility of local area networks (LANs). The results obtained by investigating the Fast Ethernet and Gigabit Ethernet LANs exposed to nanosecond electromagnetic disturbances are presented. The electromagnetic interference parameters are measured in the LAN cables.

Application of the Random Coupling Model to Electromagnetic Statistics in Complex Enclosures

Abstract: The effectiveness of the random coupling model (RCM) in predicting electromagnetic wave coupling to targeted electronic components within a complex enclosure is examined. In the short-wavelength limit with respect to the characteristic length of the enclosure, electromagnetic wave propagation within a large enclosure is sensitive to small changes to the interior, or to the boundaries of the enclosure. Such changes can reduce or invalidate the applicability of deterministic predictions of the electromagnetic fields at radiofrequencies (RF) in large enclosures. Under such circumstances, a statistical approach is needed to provide a better understanding of RF coupling to components within large enclosures. In this paper, we experimentally demonstrate the applicability of a statistical technique, the RCM, to estimate the probabilistic magnitudes of RF fields on electrically large components (i.e., long cables, etc.) that are partially shielded within a complex, 3-D enclosure.

Nonlinear interaction of meta-atoms through optical coupling

Abstract: We propose and experimentally demonstrate a multi-frequency nonlinear coupling mechanism between split-ring resonators. We engineer the coupling between two microwave resonators through optical interaction, whilst suppressing the direct electromagnetic coupling. This allows for a power-dependent interaction between the otherwise independent resonators, opening interesting opportunities to address applications in signal processing, filtering, directional coupling, and electromagnetic compatibility.

Measurement and Analysis of Compromising Emanation for Laser Printer

Abstract: The article concerns problems connected with electromagnetic compatibility and compromising emanation, i.e., information security. In the article channels of electromagnetic information permeability have been de-scribed and then there has been the focus on laser print- ers for which forcing signals used during measurements of compromising emanation have been presented and measurement results of compromising emanation deriving from laser printer have been described. 1. INTRODUCTION Information security against electromagnetic permeability of devices and electromagnetic systems (IT) is of great importance. This problem increases with a higher and higher use of ICT devices for processing and transmitting information which should not fall into the wrong hands. It results from the fact that each electronic device is the source of undesirable (secondary) emission of elec- tromagnetic energy induced in surrounding space and in all close conductors and metal structures. When signals of undesirable emission are correlated with unclassifled information, they can be used for reconstructing that information by intelligence services. The phenomenon of such undesirable emission is called compromising emanation and its use by intelligence-penetration or electromagnetic inflltration. Undertakings which aim is to hinder system recognition on the basis of compromising emanation are called information protection against electromagnetic penetration or emission safety. Electromagnetic emissions with the feature of compromising emanation can arise at any stage of processing of encoded information in the form of electric current courses. There is also no pos- sibility to conduct tests of the source itself and the channel of information permeability. However such tests can be conducted in laboratory conditions in which examined devices are introduced into operation mode allowing to learn their inflltration susceptibility. In this article an example of such experiments has been presented. It seems that most suitable for illustrating the issue of electro- magnetic information permeability are devices or their components which process information in serial way and the rule of encoding is uncomplicated and well-known.

Efficient Frequency-Domain Analysis of PEEC Circuits Through Multiscale Compressed Decomposition

Abstract: The solution of mixed electromagnetic/circuit problems is important for the electromagnetic compatibility/signal integrity/power integrity system designs. The ever-increasing frequency content of signals and decrease of geometrical features requires the 3-D electromagnetic methods, such as the partial element equivalent circuit (PEEC) method, to be used for the analysis and design of high-speed circuits. Very large systems of equations are often produced and their efficient solution can be extremely challenging. In this paper, we propose a new frequency-domain PEEC solver which is based on the adaptive cross approximation and singular value decomposition. Taking advantage of the rank deficiency of the dense partial inductance and coefficient of potential matrices, a multiscale block decomposition is adopted to explicitly compute the inverse of the admittance matrix of the PEEC circuit. The proposed approach provides both speedup and memory storage saving, while preserving the accuracy. The efficiency of the proposed method is demonstrated through its application to the PEEC modeling of typical interconnect problems.

Simulation of Low-Frequency Magnetic Fields in Automotive EMC Problems

Abstract: This paper presents a computationally efficient method for solving automotive low-frequency electromagnetic compatibility (EMC) problems by using integral equations. We consider the interaction of magnetic fields with thin, finite, conducting 3-D metallic structures, obtaining the fields radiated by these structures by using single- and double-layer equivalent currents. Our proposed numerical solution is unique in its representation of equivalent currents as the sum of solenoidal and nonsolenoidal components found using the method of moments (MoM) in two steps: first, the solenoidal currents are found using loop basis functions, after which the nonsolenoidal currents are found. Decomposing the equivalent currents into solenoidal and nonsolenoidal components provides a total solution that is computationally efficient for problems dominated by magnetic fields. We validated this numerical electromagnetic solution against semianalytical solutions and measured data and illustrated its applicability by analyzing three practical automotive problems. We then analyzed the magnetic fields generated by a power cable inside a car, suggested a methodology for optimizing the locations of antennas for smart-entry systems, and studied the EMC implications of an inductive-charging system in an electric vehicle.

A Cost-Efficient System for Detecting an Intentional Electromagnetic Interference (IEMI) attack

Abstract: This paper describes a cost-efficient Intentional EMI Detection system and gives a brief overview of the identification and location system being developed as part of the STRUCTURES project.

Full-Spectrum APD Measurement of Transient Interferences in Time Domain

Abstract: Radiated transient interferences produce severe errors to digital communication systems. Conventional measurements defined in the electromagnetic compatibility (EMC) standards are not sufficient to predict the impact of this impulsive noise on the quality of a digital system, as measurements were originally defined to protect analogue communication systems. Measurement detectors and methods based on reaching the statistical of the interference have been studied as the best option to evaluate transient interferences. For a properly EMC emissions evaluation, an amplitude probability detector (APD) has been recommended as the best option, since APD results have been correlated with bit error probability. However, carrying out APD measurements using electromagnetic interference (EMI) receivers has strong inconvenience. One of the main limitations is that measurement can only be performed with the preset filters available at the EMI receiver, which sometimes are different from the communication bandwidths causing an incorrect estimation on the degradation produced. Another restriction is the elapsed time needed to acquire the statistical APD measurement at each frequency band. This document presents a methodology to obtain the APD measurement at any frequency band employing two single time-domain oscilloscope captures. The developed measurement method makes it possible to obtain the APD at any frequency band achieving as good results as the ones acquired from EMI receivers. To show the effectiveness of the time-domain method, an exhaustive validation study is presented, in which white Gaussian noise and several impulsive interferences are evaluated at frequencies from 50 MHz up to 1 GHz.

Evaluation of the Modeling of an EM Illumination on an Aircraft Cable Harness

Abstract: This paper describes the approach developed in order to model the electromagnetic response of a cable bundle, part of the electrical wiring interconnection system of a real aircraft, submitted to an external electromagnetic excitation. The aim of this study is to highlight the main challenges in the synthetic modeling and validation of a fully real setup, from the electromagnetic compatibility point of view. Both conducted and radiated excitations have been considered in the electromagnetic global model. The solution is obtained through a cooperative simulation approach involving one 3-D full-wave solver and a multiconductor transmission line solver. The results are compared with measurements and specific tools, such as feature selective validation and integrated error against log frequency, are used to assess the adequacy of the results.

Applications of the FDTD method to lightning electromagnetic pulse and surge simulations

Abstract: Electromagnetic computation methods (ECMs) have been widely used in analyzing lightning electromagnetic pulses (LEMPs) and lightning-caused surges in various systems. One of the advantages of ECMs, in comparison with circuit simulation methods, is that they allow a self-consistent full-wave solution for both the transient current distribution in a 3D conductor system and resultant electromagnetic fields, although they are computationally expensive. Among ECMs, the finite-difference time-domain (FDTD) method for solving Maxwell's equations has been most frequently used in LEMP and surge simulations. In this paper, we review applications of the FDTD method to LEMP and surge simulations, including (i) lightning electromagnetic fields at close and far distances; (ii) lightning surges on overhead power transmission line conductors and towers, (iii) lightning surges on overhead distribution and telecommunication lines; (iv) lightning electromagnetic environment in power substations; (v) lightning surges in wind-turbine-generator towers; (vi) lightning surges in photovoltaic (PV) arrays; (vii) lightning electromagnetic environment in electric vehicles (EVs); (viii) lightning electromagnetic environment in airborne vehicles; (ix) lightning surges and electromagnetic environment in buildings; and (x) surges on grounding electrodes.

EMC Measurements for Spectrum Sharing Between LTE Signals and Radar Receivers

Abstract: In response to proposals to introduce new Long Term Evolution (LTE) microcell Citizens Broadband Service (CBS) radio systems into 3550–3650 MHz (3.5 GHz) radio spectrum in the United States, the authors have performed measurements and analysis on effects of LTE interference on the performance of a type of radar receiver that might eventually share spectrum with such systems. LTE and Gaussian noise interference were injected into a radar receiver; Gaussian noise was a proxy for aggregated interference sources and one type of LTE. Interference was injected into a radar receiver so as to appear coincident with synthetic radar targets on the radar’s display. The targets’ baseline (non-interference) probability of detection (Pd) was 90 percent. With interference present, the targets’ Pd was measured and recorded as a function of LTE signal (both on-tuned and off-tuned) and Gaussian noise interference levels. Additional data presented in this report include: the radar receiver’s antenna radiation pattern, RF front end frequency response, IF-stage frequency response, noise figure, and RF overload response up to an input power of -4.6 dBm. A measured LTE emission spectrum is also provided. Using these data, spectrum management personnel can perform electromagnetic compatibility (EMC) analyses for possible future spectrum sharing between LTE transmitters and this type of radar receiver.

Electromagnetic Interference and Radiation from Wireless Power Transfer Systems

Abstract: Wireless power transfer (WPT) technology is becoming increasingly popular for wireless charging of mobile phones and electrical vehicles. Because high power energy is transferred via air, however, the problem of electromagnetic radiated emission from WPT systems is expected to be serious. In this paper, an electromagnetic interface (EMI) and radiation from WPT systems are discussed. Three example technologies for suppressing the electromagnetic-field (EMF) noise and EMI noise from WPT systems are presented. EMF noise from different receiving (RX) coil topologies is characterized and an EMF noise suppression technology using a ferromagnetic material and metallic shielding is analyzed. A handheld resonant magnetic coupling charger (HH-RMCC), a WPT system with very low EMI noise, is then introduced. The proposed technologies for suppressing EMF and EMI noise from a WPT system will be helpful to design engineers.

Near Magnetic Field Coupling Prediction Using Equivalent Spherical Harmonic Sources

Abstract: In the electromagnetic compatibility (EMC) behavior of power electronic converters, magnetic parasitic couplings between components are one of the main causes of dysfunctions or bad filtering (e.g., in EMC filter). These couplings could be as conducted or near-field interferences. In order to handle interaction problems, a complete knowledge of these magnetic couplings is then necessary. Our study is focused on near magnetic field's interferences. Indeed, the characterization of electromagnetic field in power electronics is still in active research. This paper details a predictive method that calculates accurately and efficiently the near magnetic field coupling between two sources. By using the near-field multipolar expansion in spherical harmonics of electromagnetic sources, the close magnetic coupling between two sources is determined from their equivalent model. It is shown that the increase in degree up to the fourth provides a more precise representation of the elements and thus a better accuracy of the near-field coupling prediction. Also, theoretical and experimental developments will be presented. The coupling between two complex sources will be considered to validate the predictive method.

Calculation of Current Distribution in the Lightning Protective System of a Residential House

Abstract: The lightning current distribution in the lightning protective system (LPS) of a residential house was experimentally studied in 2004 and 2005 at the International Center for Lightning Research and Testing. In this paper, the lightning current distribution in the LPS is calculated based on the distributed parameter circuit in the frequency domain. The electromagnetic coupling between the LPS and lightning channel is considered. The lightning channel and the connecting wire between the launch tower and the test house are modeled as vertical and horizontal dipoles above lossy ground. An improved discrete complex images method is presented to calculate the electromagnetic field of the lightning current. The lightning current distribution in the LPS is also calculated by means of the commercial software CDEGS, and the calculated currents in the LPS are compared with those measured.

A study of electromagnetic field generated by high voltage lines using COMSOL MULTIPHYSICS

Abstract: Possible harmful effect of the low frequency electric and magnetic field on human health. This paper investigates using the COMSOL MULTIPHYSICS software modules in calculating the electromagnetic fields generated in the vicinity of High Voltage (HV) power transmission lines. The presented results in this paper demonstrate the effectiveness of using the electrostatic and magneto static modules of the COMSOL MULTIPHYSICS in electromagnetic fields calculation at many levels near power transmission lines. The resulting fields are compared with the International Commission on Non Ionizing Radiation Protection (ICNIRP) field guidelines.

On Finding the Optimal Number of Decoupling Capacitors by Minimizing the Equivalent Inductance of the PCB PDN

Abstract: PCB-PDN design remains a challenge with the reducing noise margins. One aspect of PDN design is finding the number of decoupling capacitors required for each power rail. As more capacitors are added, the mid frequency equivalent inductance in the impedance of the PCB-PDN converges to a minimum value for each placement pattern. This convergence is studied for different placement patterns to find the least number of capacitors required to satisfy a certain convergence criteria. A first principle method is used resonant cavity model for the analysis.

Control Strategy for Current Harmonic Programmed AC Active Electronic Power Loads

Abstract: Alternating current (ac) active electronic loads (AELs) based on pulsewidth modulation (PWM) converters, capable of emulating nonlinear loads, require effective current control techniques and power stages. These two aspects of an AEL are interdependent mainly due to the presence of electromagnetic compatibility filters to reduce electromagnetic emissions. However, the filter components affect the dynamics of the system. In this context, this paper proposes a digitally implemented control strategy comprising the state feedback, robust observer, phase-locked loop, and linear current controller to cope with ac AEL applications. The control-oriented modeling and the control system design are presented. Experimental results obtained from a 10-kW three-phase three-level PWM converter prototype illustrate and demonstrate the feasibility of the proposed AEL control strategy.

The Influence of Network Impedance on Conducted Disturbances Within the High-Voltage Traction Harness of Electric Vehicles

Abstract: Currently, automotive traction systems are increasingly being revised from combustion engine drives to electric propulsion. The high power cables of electric vehicles are routed close to various communication, sensor, or control units. This circumstance results in a tightened challenge for the developing engineers, who need to ensure the electromagnetic compatibility of these miscellaneous and adjacent systems. A trial-and-error approach in the development process of electromagnetic interference filters can only be avoided if the influence of the network impedances within the high voltage traction harness on conducted RF disturbances is known. This contribution presents the current methodology of determining the conducted emissions of power inverters for electric driven cars. It highlights the differences between the traditional low-voltage cable wiring and novel high-voltage traction harnesses, and their impact on the network impedances. An adaption of the line impedance stabilization networks used recently to the characteristic impedance of the high-voltage cables applied shows the influence of termination mismatch on conducted emissions within the traction harness. High-voltage components employed in a car are usually supplied by a traction accumulator battery, which acts as transmission line termination. The influence of a battery's input impedances on disturbances within a component level EMC test setup is shown.

Robustness of remote keyless entry systems to intentional electromagnetic interference

Abstract: Cars equipped with remote keyless entry systems are very vulnerable to electromagnetic interference because of the wireless link. Carrying the encrypted signal between the key fob and the car, it can deliberately be jammed by a malicious person. Jamming on the physical layer leaves the encryption and code algorithms on the higher communication layers useless. Jamming for criminal purposes is considered to be intentional electromagnetic interference. In this paper, the robustness of the remote keyless entry system to intentional electromagnetic interference is investigated. Two commercially available remote keyless entry systems are analyzed. Measurements are performed in an anechoic chamber to estimate the robustness of the RF receivers. Both systems are equipped with super regenerative receivers. Results show that the selectivity of both systems are poor and they are easily jammed. Field strenghts as low as 0.1 V/m can already jam the wireless link over a wide frequency bandwidth of 4 MHz. A super heterodyne receiver would be robuster to electromagnetic interference than a super regenerative receiver, but this type of receiver has a relative high cost.