Showing papers on "Electromagnetic compatibility published in 2018"

Learning-by-examples techniques as applied to electromagnetics

Abstract: There is a wide number of problems in electromagnetic (EM) engineering that require a real-time response or in which the input–output relationship is not a-priori known or cannot be defined due to ...

Reverberation Chambers for Over-the-Air Tests: An Overview of Two Decades of Research

Abstract: The reverberation chamber (RC) has traditionally been used for electromagnetic compatibility tests About two decade ago, it found application in various over-the-air (OTA) tests of antennas and wireless devices This paper gives an overview of nearly two decades of research on the RC-based OTA tests, ranging from antenna measurements and characterizations to OTA tests of both terminals and base stations Apart from the advantages of the RC-based OTA tests, some important issues are identified

Methodology for Characterization of Common-Mode Conducted Electromagnetic Emissions in Wide-Bandgap Converters for Ungrounded Shipboard Applications

Abstract: This paper describes the development of a dedicated electromagnetic interference (EMI) characterization platform for the evaluation of wide bandgap-based converters in ungrounded architectures of the type likely to be employed on the future shipboard systems. This platform is designed to support the characterization of wide-bandgap-based converters operating at switching frequencies of hundreds of kilohertz; with power levels up to 100 kVA and with expected emissions up to 100 MHz. To illustrate the capabilities of this platform, the conducted emissions of a SiC-based half-bridge converter are evaluated (with a focus on common-mode (CM) behavior), and a parametric study is conducted which considers variations in the impedance between the half-bridge module base plate and a representative grounding structure. The focus of this work is not only the half-bridge converter which serves as the preliminary test subject, but also rather the custom metrological setup used for characterization, which is designed to discover sensitivities to resonant paths so that the design guidelines for peripheral structures and EMI mitigating components can be developed in the future studies. One major contribution of this work is the discovery that the symmetry of the parasitic capacitances within the converter’s multichip power module is an important factor which significantly influences the CM conducted emissions of the half-bridge structure, which serves as a building block for more complex converter topologies.

Improving the Reliability of Relay-Protection and Automatic Systems of Electric-Power Stations and Substations

Abstract: The main reasons for false (incorrect) triggering of microprocessor relay-protection systems are analyzed. Methods of increasing the reliability indicators of relay-automated systems are considered. Analysis of statistical data revealed that the probability of no-failure operation of microprocessor relay-protection systems is no lower than 0.998. Increasing the reliability indicators of microprocessor-protection systems does not require a revision of the Electrical Installation Rules, but requires using high-quality cable products with normalized technical characteristics and transition to a digital data-transfer format with a limited number of variables transmitted by one serial channel. The approximate upper and lower bounds of dependence of the cost of improving the reliability of microprocessor system are stated. For example, halving the amount of failures requires increasing the capital costs for electromagnetic protection by three to four times. Maintenance of the level of reliability of microprocessor system during operation is possible only during implementation of routine measures of evaluating the electromagnetic environment. Statistical data showed that the most likely cause of incorrect triggering of relay automation is atmospheric phenomena—lightnings and ensuing overvoltage. Therefore, at the stage of determination of the electromagnetic state, it is necessary to note the state of the earthing system it is most appropriate to carry out fault diagostics using the half-interval method taking into account the possibility of no-failure operation.

Automatic EMI filter design for power electronic converters oriented to high power density

Abstract: In this paper, a complete computer aided procedure based on the power density concept and aimed at the automatic design of EMI filters for power electronic converters is presented. It is rule-based, and it uses suitable databases built-up by considering information on passive components available from commercial datasheets. The power density constraint is taken into consideration by imposing the minimization of the filter volume and/or weight; nevertheless, the system in which the automatically designed filter is included satisfies the electromagnetic compatibility standards limits. Experimental validations of the proposed procedure are presented for two real case studies, for which the performance and the size of the best filter design are compared with those related to a conventionally designed one.

Random Modulation in Inverters With Respect to Electromagnetic Compatibility and Power Quality

Abstract: Random modulations are treated as one of the solutions for reducing conducted electromagnetic interference (EMI) in power electronics inverters. Although in papers related to inverters, this view has not been clearly demonstrated. Especially in the state-of-the-art papers related to randomly modulated inverters, it is hard to find information about EMI measurement procedures or deeper EMC analyses. Therefore, this paper will discuss the influence of random modulations used in power electronic inverters on selected issues related to inverter EMC and power quality. A complete case study is carried out on a three-phase inverter. The undertaken analysis refers to the generation of interference, EMI measurement methodology, the conditioning of EMI filtration, and the quality of output voltage. The results show which EMI parameters are improved and which parameters are aggravated, when random modulation is used. The presented results show that random modulation should be applied in inverters with great caution. In addition, we show the limitations of EMI measurement methods and propose a more reliable way to assess the EMI spectrum.

Noncontact Wideband Current Probes With High Sensitivity and Spatial Resolution for Noise Location on PCB

Abstract: This paper develops an improved noncontact current probe for locating the noise source to estimate the electromagnetic interference emission on printed circuit board (PCB). The miniature current probe is fabricated in a four-layer PCB with high-performance dielectric RO4003C. The designs of isolated via array and matching via-pad structures are used to optimize the performance of probe. The probe can then be used for wideband electromagnetic compatibility test from 9 kHz to 10 GHz under narrow and complex conditions. The current probe can be sensitive enough to detect the weak current signal as small as −130 dBA and has a spatial resolution of 1 mm. The application of current probe in noise location on PCBs based on measured surface scan method is investigated in this paper. And two near-field measurement results compared with the reference probe are used to illustrate the new features of the probe.

Modelling of the Return Traction Current Harmonics Distribution in Rails for AC Electric Railway System

Abstract: The problem of determination of the traction current harmonics distribution in rails generated by several trains that operated in AC feeder zone is considered. The investigations were caused by necessity to ensure electromagnetic compatibility of the new types of rolling stock equipped with electronic static converters with track circuits that are used in train movement control systems for detection of their positions. The great diversity of rolling stock, power supply and return current systems, and train detection systems installed in European countries leads to consideration of the electromagnetic compatibility problem taking into account the specific railway systems used in the each country. Investigation of the electromagnetic compatibility between different railway subsystems requires the use of simulation programs that help to reveal most critical conditions for electromagnetic compatibility at an early stage and also makes it possible to estimate electromagnetic interference from rolling stock in rails under the worst-case conditions, realization of which in the operating systems will require a lot of time and cost. This work consider evolved model for distribution of the traction current harmonics in rails from several trains. To illustrate the application of the considered model, the distribution of the traction current harmonics in rails was computed for25 kV AC direct feeding network depending on distance from electrical supply substation, the rail-to-earth conductance, and the number of trains in the feeder zone. The results of modeling of the harmonics distribution are in satisfactory agreement with the experimental data.

Electromagnetic Compatibility Prediction Method Under the Multifrequency in-Band Interference Environment

Abstract: An electromagnetic compatibility (EMC) prediction method is proposed to overcome the insufficiency of the single frequency threshold and prediction methods of statistical analysis. Two prediction models are established based on different sensitive parameters by analysis of the interference mechanism. Effect index is defined to predict EMC. If the effect index reaches or exceeds 1, the communication equipment will be disturbed. The radiation test platform of multifrequency in-band interference is designed, with two different types of communication radios as the equipment under test (EUT). The sine and amplitude modulation (AM) wave, dual-frequency, and tri-frequency radiation tests were performed. Test results show that the sensitive parameter of equipment can be distinguished by sine and AM wave susceptibility threshold; all of the effect indexes of EUT I which is sensitive to peak-field strength exceed 1 and all of the effect indexes of EUT II which is sensitive to average power are around 1. For reducing the model error, the modified Model I is proposed and the effect indexes of EUT I are about 1.1. The method in this paper can effectively solve the problem of multifrequency in-band EMC prediction for the communication equipment and improve EMC standards.

A Low-EMI, High-Reliability PWM-Based Dual-Phase LED Driver for Automotive Lighting

Abstract: Light-emitting diode (LED) drivers for automotive lighting applications adopt pulsewidth modulation (PWM) vis-a-vis pulse frequency modulation because its ensuing electromagnetic interference (EMI) spectrum is predictable and easily mitigated. Nevertheless, present-day PWM control schemes adopted in LED drivers suffer from imprecise output current and subharmonic oscillation, which compromises reliability. In this paper, we present a PWM-based LED driver that features low EMI and high reliability. These attributes are achieved by our proposed average current control (ACC), proposed accuracy-enhanced on-chip current sensors, and our adoption of a dual-phase power stage. The ACC eliminates subharmonic oscillation by means of considering the complete inductor current profile vis-a-vis peak current adopted elsewhere. Also by means of the dual-phase power stage, good current balance and small current ripple are obtained. Collectively, the aforesaid substantially improves the reliability. To improve electromagnetic compatibility (EMC), the proposed accuracy-enhanced on-chip current sensors are monolithically realized with the ACC and power transistors—to the best of our knowledge, the first for a PWM-based dual-phase LED driver. The prototype LED driver, realized in a 130-nm BCDLite process, has an input voltage range of 5–16 V, output to drive 1–3 series-connected LEDs, provides a current regulation accuracy of at least 96.2%, dimming frequency up to 20 kHz, features a peak power efficiency of 94.7%, settling time of $5~\mu \text{s}$ , LED current range of 0.4–2.4 A, and current ripple factor of 8%. When benchmarked against the state-of-the-art LED drivers, our design features the highest peak power efficiency, the shortest settling time, highest current driving capability, and the lowest current ripple factor.

An ultra-thin polarization independent quad-band microwave absorber-based on compact metamaterial structures for EMI/EMC applications

Abstract: In this paper, a compact metamaterial inspired ultra-thin polarization independent quad-band microwave absorber for electromagnetic interference (EMI)/ electromagnetic compatibility (EMC) applications have been discussed. The proposed absorber structure offers four different absorption peaks having absorptivity of 97.02, 94.07, 91.72, and 98.20% at 3.40, 8.23, 9.89, and 11.80 GHz, respectively. Due to the four-fold symmetry of the designed unit cell, the proposed absorber structure shows polarization independent behavior. In addition to above, the absorption curve for the designed structure has been also analyzed under different angles of incidence for both transverse electric and transverse magnetic polarization states. In order to confirm the metamaterial behavior of the proposed absorber unit cell, dispersion plot has been studied. Further, input impedance plot, electric field, and surface current distribution plot have been discussed to explain the absorption mechanism of the proposed absorber structure. The designed absorber unit cell shows compactness of 0.136 λ0 × 0.136 λ0 with the ultra-thin thickness of 0.0113 λ0, where λ0 (free space wavelength) corresponds to the lowest absorption peak of 3.40 GHz. In order to calculate the measured value of absorptivity, the designed absorber structure has been fabricated. Further, it has been observed that simulated and measured results perfectly match with each other. The ultra-thin and compact nature of the proposed absorber structure suggests its potential use in the field of various EMI/EMC applications.

Effectiveness of Hamming Single Error Correction Codes Under Harsh Electromagnetic Disturbances

Abstract: Modern hi-tech systems rely heavily on communication networks while operating in increasingly harsher electromagnetic conditions. To protect transmitted data from corruption, Error Correcting Codes are widely used. In this paper, the effectiveness of the Hamming code is evaluated under harsh electromagnetic disturbances. Our simulations show that, under certain conditions, the impact of the introduced overhead cannot be compensated by the single error correcting capabilities of the Hamming codes. Moreover, for specific bit and disturbance frequencies and for larger data sets, the use of a Hamming code provides limited to no advantage.

Review of the EMC Aspects of Internet of Things

Abstract: Wireless devices are the largest part of the Internet-of-Things (IoT) units. Radiated, such as specific absorption rate and spurious related issues are regulated by the standards bodies. The functionality performance will greatly influence IoT system stability, user experience, and cost. Radio receiver desensitization and coexistence aspects of IoT devices are discussed in this article. Measurement technologies are briefly reviewed for transmit/receive mode only of single-input single-output (SISO), and multiple-input multiple-output (MIMO) devices, to provide a means of device performance evaluation and electromagnetic interference troubleshooting. An understanding of the electromagnetic compatibility aspects of the IoT and its measurement methods can help ensure the best user experience for ubiquitous wireless systems.

Analysis of a Hybrid Rotor Permanent Magnet Motor Based on Equivalent Magnetic Network

Abstract: An equivalent magnetic circuit (EMC) model is built for a hybrid rotor permanent magnet (HRPM) motor. The key of the EMC model is that a novel section modeling method for permanent magnet (PM) is proposed to take PM end-leakage and local saturation of magnetic bridge into consideration, and it is used to separate the main magnetic circuit and leakage magnetic circuit of PM. Besides, a generalized equivalent method of winding magnetomotive force is adopted for the modeling of distributed winding. Meanwhile, an improved iterative algorithm is presented to solve the problem that the iteration does not converge when iron core is severely saturated. Then, the accuracy of the proposed EMC model is evaluated by experimental test and finite-element analysis. Finally, frozen permeability method based on the proposed EMC model is utilized to separate the PM torque component and the reluctance torque, which is time saving, and can be used to investigate and optimize the torque-angle characteristic clearly.

EMI Filter Design for a Single-stage Bidirectional and Isolated AC–DC Matrix Converter

Abstract: This paper describes the design of an electromagnetic interference (EMI) filter for the high-frequency link matrix converter (HFLMC). The proposed method aims to systematize the design process for pre-compliance with CISPR 11 Class B standard in the frequency range 150 kHz to 30 MHz. This approach can be extended to other current source converters which allows time-savings during the project of the filter. Conducted emissions are estimated through extended simulation and take into account the effect of the measurement apparatus. Differential-mode (DM) and common-mode (CM) filtering stages are projected separately and then integrated in a synergistic way in a single PCB to reduce volume and weight. A prototype of the filter was constructed and tested in the laboratory. Experimental results with the characterization of the insertion losses following the CISPR 17 standard are provided. The attenuation capability of the filter was demonstrated in the final part of the paper.

Effectiveness of Time Diversity to Obtain EMI-Diverse Redundant Systems

Abstract: In this paper, the effectiveness of applying an extra time delay to the data transmitted over redundant channels to cope with harsh electromagnetic interference is studied. The redundant system is compared with and without extra time delay and compared with a non-redundant system, which is the reference situation. The geometries under study are disturbed by strong incident fields, which represent reverberation room conditions. These conditions refer to the planewave integral representation, where multiple planewaves with random angles, polarisations and phases are combined and normalised, to create a reverberation room like environment. A reciprocity based technique is used to efficiently calculate the induced voltages and the resulting bit error rate for the different situations. Because of the properties of the geometries that are under test and the introduction of a time-delay in the transmitted datastream, the moment the induced voltage due to EMI is sampled is different, which causes an EMI-diverse system. The results show that using time-diverse signals optimized for the main disturbance frequency to be expected, is a very effective way of creating EMI-diverse behaviour. In a majority voting (2oo3) system it is possible to eliminate all triple occuring faults. Even for higher field strengths and different EMI frequencies, the time diversity method performs well (better than other EMI-diverse techniques).

EMC and EMI issues of WPT systems for wearable and implantable devices

Abstract: This paper discusses the electromagnetic compatibility and interference aspects related to wireless power transfer (WPT) systems for wearable and implantable devices. The cases of a near-field (reactive) link for recharging a pacemaker and a far-field (radiative) link for wearable devices are considered. For the first case a design approach, able to perform efficient energy transfer under the safety regulations constraints of medical devices is proposed. In the second case, a rigorous methodology is proposed to predict the transferred energy to a worn device able to account for interferences due to the human body or any other wireless system located close to the worn device. An implementation of grounded worn rectennas in the presence of unconventional radio channels is presented.

About Electromagnetic Compatibility of Track Circuits with the Traction Supply System of Railway

Abstract: Track circuits are of fundamental importance for the safety in railway systems. Thus, they must be immune from electromagnetic interference (EMI). To this aim they must be accurately characterized. The paper deals with the determination of spectrum composition of traction current with the electric traction. A method of measuring the parameters of track circuits (time and amplitude parameters of code current, flowing in rail lines, an input impedance of a track circuit, characteristic impedance and propagation constant) is considered Automated method of measurement of parameters of track circuits and harmonics of return traction current was elaborated by the car-laboratory. The harmonics coinciding with the code frequency are inadmissible for the track circuits.

Study of UWB Electromagnetic Pulse Impact on Commercial Unmanned Aerial Vehicle

Abstract: In this paper investigations of ultra-wideband (UWB) electromagnetic pulse (EMP) effects on commercial unmanned aerial vehicle (UAV) DJI Phantom 3 Standard are considered. The UAVs vulnerability to UWB EMP was detected. Radiated pulses parameters were obtained and fault types of equipment under test were classified. The characteristics of UWB EMP radiator prototype for UAV jamming are proposed.

Black Box EMC Modeling of a Three Phase Inverter

Abstract: This paper presents an Electromagnetic Interferences (EMI) modeling of a DC-AC power converter, based on a black box representation: the converter is represented by an association of sources and impedances that reflect its external EMI behavior. This modeling approach presented in this paper requires a very short computation time, which allows an optimized design of an EMC filter or an interaction study between several converters connected on the same electrical network. This EMC model depending on a given operation point of the converter, the second part of this paper is dedicated to the study of the load influence on this behavioral model.

Desense Prediction and Mitigation from DDR Noise Source

Abstract: Ahstract- In this paper, the dipole-moment based reciprocity method is used to perform desense prediction and mitigation from the DDR noise source to the nearby RF antenna. The noise source is from the DDR signals between the application processor and the memory IC. Radiation physics of the noise source is analyzed by understanding of the current flow. Firstly, the random nature of the DDR signals is analyzed using the measurement data. Based on the measurement data, the setup of the near field scanning is further determined. The desense prediction procedures are decomposed into two steps: the forward problem and the reverse problem. In the forward problem, the noise source is approximately regarded as a single magnetic dipole moment based on the near field scanning above this specific electronic device. In the reverse problem, the transfer function from the magnetic dipole moment to the victim antenna is obtained by measuring the H field when the victim antenna radiates. Based on the measurements of forward and reverse problem, the coupled noise to the victim antenna can be analytically estimated. The estimated RFI results are compared with direct RFI measurement to validate the dipole-moment based reciprocity method. Lastly, a few methods to mitigate the desense are also discussed.

Characterization of Different Cable Ferrite Materials to Reduce the Electromagnetic Noise in the 2–150 kHz Frequency Range

Abstract: The gap of standardization for conducted and field coupled electromagnetic interferences (EMI) in the 2–150 kHz frequency range can lead to Electromagnetic Compatibility (EMC) problems. This is caused by power systems such as Pulse Width Modulation (PWM) controlled rectifiers, photovoltaic inverters or charging battery units in electric vehicles. This is a very important frequency spectral due to interferences generated in a wide range of devices and, specifically, communication problems in the new technologies and devices incorporated to the traditional grid to convert it into a Smart Grid. Consequently, it is necessary to provide new solutions to attenuate this kind of interference, which involves finding new materials that are able to filter the electromagnetic noise. This contribution is focused on characterizing the performance of a novel material based on nanocrystalline and comparing it to most common material compositions such as MnZn and NiZn. This research is carried out from the point of view of the manufacturing process, magnetic properties and EMI suppression ability. This last item is carried out through two analysis procedures: a theoretical method by determining the attenuation ratio by measuring impedance parameter and proposing a new empirical technique based on measuring directly the insertion loss parameter. Therefore, the main aim of this characterization process is to determine the performance of nanocrystalline compared to traditional cable ferrite compositions to reduce the interferences in this controversial frequency range. From the results obtained, it is possible to deduce that nanocrystalline cable ferrite provides the best performance to filter the electromagnetic noise in the 2–150 kHz frequency range.

Common-ground transformerless inverter for solar photovoltaic module

Abstract: This paper presents a new single-phase transformerless inverter providing common ground for grid-connected photovoltaic (PV) systems. It consists of 5 switches, one diode, one capacitor, one small inductor and a small filter at the output stage. A simple Unipolar Sinusoidal Pulse-Width Modulation (SPWM) technique is used to operate the proposed inverter to minimize losses, output current ripple, filter requirements and improve its electromagnetic compatibility (EMC). The proposed topology shares a common ground with the grid and a capacitor is utilized as a virtual DC bus to provide the negative power cycle of the inverter. The capacitor is charged regardless of any switching cycle using a dedicated switch which can in turn reduce the size of capacitor in relation to the switching frequency. The peak ac output voltage is equal to the input DC voltage which reduces the requirement of the high input DC voltages. Simulation and experimental results for a 1 kW prototype are presented to demonstrate the usefulness of the proposed topology.

Common Mode Noise Propagation and Effects in a Four-Wheel Drive Electric Vehicle

Abstract: New topologies of electric car use high power switching devices which must be integrated with a growing range of electronic systems in small places A good performance of the car relies on the electromagnetic compatibility among these systems, which requires the characterization of the noise and interferences present in the system To characterize the noise, both emission and susceptibility issues as well as coupling mechanisms must be studied This paper presents the work performed for the electromagnetic mapping of a four-wheel fully electric car, which involves both simulation and experimental measurements It has been carried out within the E-VECTOORC project (FP7-INFSO-284708), in collaboration with car manufacturers such as Jaguar Land Rover and Skoda

The Analysis of the Noise Immunity of an Electronic Device Under the Action of Electrostatic Discharge

Abstract: The paper presents the results of experimental studies of the noise immunity of a personal computer under the action of electrostatic discharge. The analysis of electromagnetic interference in communication lines of electronic devices during of pulsed electrostatic discharge on the metal parts of the case are presented. A mathematical model for predicting interference is constructed. A comparison of the experimental results and modeling is carried out.

Evaluation of Multichannel Synchronous Conducted TDEMI Measurements for High Voltage Power Electronics

Abstract: Safely measuring high power conducted electromagnetic interference (EMI) is an issue to be addressed, where a possible measurement strategy is being discussed in this paper which uses the benefits of multi-channel synchronous time-domain electromagnetic interference (TDEMI) measurements. Only the differential mode (DM) voltage has been evaluated in this paper, however the setup is not limited in this respect. Common mode (CM) voltage can also be synchronously analyzed with this setup. Nevertheless, with respect to the to be measured amplitudes, DM voltages in this particular system offer a larger challenge and are addressed. The setup was developed with respect to Low-Frequency conducted EMI measurements in high power, fast switching systems using a low-cost solution.

Suppression of a Certain Vehicle Electrical Field and Magnetic Field Radiation Resonance Point

Abstract: The pulse-width-modulation-controlled inverter and the permanent-magnet synchronous motor are the key electrical components of the electric vehicle (EV). The electromagnetic radiation emission of the motor drive system has a great influence on the electromagnetic radiation emission of the vehicle to a certain extent. Different motor drive systems may have significant differences in the design of the inverter electromagnetic compatibility, the length, and the direction of the cable, which resulting in a significant difference in the radiation emission of the motor drive system. At present, there are many researches on the conduction emission, electromagnetic interference (EMI) modeling, and EMI suppression of the inverter and the motor, but the research on the radiation emission of the motor drive system and its relationship with radiation emission of the vehicle is relatively little. In this paper, a certain EV is taken as an example to analyze the reason why the electric motor drive system is the source of the high emission amplitude in the frequency range from 0.50 to 3 MHz and the resonance point. Also, it is proved that it is feasible to add Y capacitor at inverter's dc terminal. It is effective to reduce the radiation emission of the vehicle in the above frequency range particularly, and a simplified vehicle common-mode interference model is established. Finally, the availability of the model is verified on multiple models.

Risk-based vs Rule-based Electromagnetic Compatibility in Large Installations

Abstract: Many engineers (still) think that if the equipment fulfils the applicable standard, that a large installation will work first-time-right. This rule-based approach, i.e. following electromagnetic interference standards, is the basic methodology for small apparatus. But for complex and large installations we need a smarter approach, based on assessing and controlling the electromagnetic risks. This trend is also visible in the newest European Directives where a risk-based approach is even mandatory; This shall result in electromagnetic compatible systems operating properly in their intended environment. This risk-based approach is described, the process and methodology is detailed, and some examples are given in this paper.