Electromagnetic Interference Issues Research Articles

Notice of Retraction: Identifying Interference From Multiple Noise Sources by Magnetic Near Fields Only

As electronic products become more and more complicated, multiple noise sources very likely interfere with the radio frequency receiver simultaneously. This paper proposes a method to identify the interference from different noise sources separately, even when they are radiating at the same time. This method converts magnetic fields to electric fields by the finite-element method (FEM) and employs the decomposition method based on reciprocity theory. In the proposed method, Huygens's surface will be set up for each source. The tangential magnetic near fields on each Huygens's surface are used to solve tangential electric fields correspondingly by the FEM. Then, the sources are removed but their Huygens's surfaces are kept. The victim structure is excited in this case to get the tangential magnetic fields on Huygens's surfaces. A creative FEM processing procedure is applied to obtain tangential electric fields in this situation. Finally, with these two groups of fields, the interference from each noise source can be estimated separately based on reciprocity theory. This method is validated by a numerical example. It is very helpful for engineers to be able to identify the contribution of the coupling from different sources and further solve the electromagnetic interference issues efficiently.

Co-Existence Analysis on Satellite-Terrestrial Integrated IMT System

As a powerful supplement, satellite component has been already investigated into international mobile telecommunications (IMT) systems. In accordance with the Radio Regulation of International Telecommunication Union (ITU), satellite components of IMT are being considered for deployment in adjacent or even the same frequency bands of IMT terrestrial components being deployed. Since the satellite and terrestrial components of IMT under consideration are envisaged to cover multiple countries, the potential electromagnetic interference (EMI) issues need to be studied. In this paper, electromagnetic compatibility (EMC) between satellite and terrestrial components of IMT is studied. Numerical simulations show that mutual interference between satellite and terrestrial components cannot be ignored no matter which orbit altitude is chosen. Therefore, several anti-interference measures are also analyzed to avoid harmful mutual interference between them.

A Multiplexed Current Sensors-Based Phase Current Detection Scheme for Multiphase SRMs

This paper proposes a promising cost-effective phase current detection scheme for different multiphase switched reluctance motors (SRMs) by employing the multiplexed current sensors. According to the phase current characteristics for the odd-numbered multiphase SRM with m phases and even-numbered multiphase SRM with n phases, the phase windings are specially divided into ( m + 1)/2 and n /2 groups, respectively, and each group shares one Hall-effect current sensor. By building the matrix functions to express the relationship between phase currents and sensor currents, the phase currents can be calculated in real time with a simple algorithm and fewer current sensors. Compared to existing phase current detection schemes, the developed method has high universality and can achieve the intact phase current detection without losing any excitation, freewheeling, and demagnetization currents. Moreover, the presented method is easy to implement without any converter change and pulse injection, which shows great potential for massive industrial application to avoid the voltage penalty, current distortion, higher switching loss, and further electromagnetic interference issues. The simulation and experiments are carried out to validate the feasibility and effectiveness of the developed phase current detection scheme.

A Universal High-Frequency Induction Machine Model and Characterization Method for Arbitrary Stator Winding Connections

High-frequency modeling of induction machines plays an important role in investigating motor drive electromagnetic interference issues such as stator winding reflected-wave overvoltage and bearing discharging current. Characterization of high-frequency machine models requires measurements of machine's differential-mode (DM) and common-mode (CM) impedances up to tens of MHz. The machine's stator winding connections, e.g., single-, and series-, parallel-winding Y/Δ configurations, influence the measured DM and CM impedances and model parameters. In this paper, a universal high-frequency equivalent circuit model capable of representing induction machines with arbitrary stator winding connections is proposed. The new model features a simple structure with a straightforward characterization method. Specifically, only one stator winding configuration is required for impedance measurements to fully characterize the machine model for arbitrary stator winding connections. The proposed methodology is demonstrated using a 7.5 hp dual-voltage nine-terminal/lead induction machine and a drive system. The simulated DM and CM impedances as well as the motor overvoltages show excellent agreement with the experimental results. The proposed model and characterization method represent significant improvement in terms of accuracy, applicability/generality, and convenience compared to prior conventional models.

Predictive Common-Mode Voltage Suppression Method Based on Current Ripple for Permanent Magnet Synchronous Motors

Compared with the pulsewidth modulation-based field-oriented control scheme, finite control set model predictive control (FCS-MPC), which has been widely concerned, has great advantages in fast dynamic response, multiobjective control, and system constraint processing. The common-mode voltage (CMV) generated by the inverter will lead to bearing damage and electromagnetic interference issues. This paper studies CMV suppression method based on FCS-MPC for permanent magnet synchronous motor fed by voltage source inverter. The use of zero voltage vector can significantly increase the output CMV of the inverter. The method of abandoning the zero vector directly can decrease CMV, but will lead to larger current distortion. Replacing the zero vector with nonadjacent vectors is a better way but will lead to higher switching frequency. When the CMV is introduced into the cost function, the tradeoff between CMV suppression and current distortion can be realized, but there is no rule to be followed for weight coefficient design. In this paper, we propose a variable FCS scheme based on current ripple. Based on this scheme, CMV can be suppressed under the premise that the current distortion is small, and the switching frequency is not significantly increased. Based on the proposed method, current distortion and CMV can be well balanced under different load conditions by setting the relative error limits. Experimental results show that the proposed method has good control performance under various operation conditions.

Extraction of Equivalent Noise Source Model From Photovoltaic Systems

Photovoltaic (PV) systems have become popular as one of the renewable energy sources in recent years. With increasing number of PV systems, potential electromagnetic interference (EMI) issues from the PV systems cannot be ignored. In order to evaluate the EMI potential of a PV system, an in-circuit measurement method to extract its equivalent common-mode and differential-mode noise source models is described and validated. These noise source models serve as black boxes for further EMI analyses.

Design and evaluation of SiC multichip power module with low and symmetrical inductance

Compared to silicon devices, silicon carbide (SiC) devices have much lower Coss and Qg; they can switch at much higher speed, SiC power modules are thus more sensitive to stray parameters. Large stray inductance may result in high voltage spikes and cause severe electro-magnetic interference (EMI) issues; unbalanced stray inductance may contribute to uneven current sharing between parallel devices. Low and symmetrical inductance is a necessity to fully utilise the superior characteristics of SiC devices. This paper first studies the current sharing and voltage spike mechanisms of multichip power modules (MCPMs). Stray inductance distribution, current sharing as well as voltage spikes under different direct bonded copper (DBC) layout conditions are investigated using finite element modelling software. A round symmetrical DBC layout is then proposed. Compared with conventional ones, the proposed structure is symmetrical in stray inductance distribution; thus improving the consistency among chips. To reduce the total equivalent stray inductance and tackle the voltage spike problem, this study further presents an improved 3D structure on the basis of the round symmetrical DBC. The stray inductance extraction and double pulse simulation results verify the effectiveness of the improved 3D structure in current sharing as well as voltage spike reduction.

Criteria for Using Antiparallel SiC SBDs With SiC mosfets for SiC-Based Inverters

The paper confirms that removing antiparallel silicon carbide (SiC) Schottky barrier diodes (SBDs) from SiC-based inverters offers positive effects without critical impact on inverter loss and electromagnetic interference (EMI) issues, moreover, the removal of SBDs reduces the inverter losses in many cases and noise emissions. This conclusion leads to the possibility to improve the power densities by removing SBDs. However, the removal of SBDs may cause some disadvantages such as an increase of the reverse conduction loss and influence of the body diode recovery phenomenon. Therefore, a comprehensive investigation of these advantages and disadvantages is necessary. In this paper, design criteria are proposed to clarify the conditions in which SiC-based inverters without SBDs have advantages over those with SBDs from the viewpoint of losses. On the other hand, to achieve the removal of SBDs, it is also necessary to confirm that removing SBDs does not cause severe EMI issues. The paper confirms that switching noises are reduced by the removal of SBDs; this is due to the larger damping effect of the SiC mosfet s without SBDs than that of SiC mosfet s with SBDs. The validity of the theoretical analyses and design criteria is confirmed with comprehensive experimental results.

Electromagnetic Interference Issue in Safety Systems Applied at Airports

Abstract The proper operation of electronic devices used in transport facilities is possible by protecting them against the effect of adverse electromagnetic fields. At present, all kinds of facilities, including critical infrastructure facilities, intended for functioning in peace conditions and emergency states, are equipped with power systems and numerous electronic devices, including electronic safety systems. On the basis of observing the process of their operation, it can be concluded that an artificially generated intended or unintended electromagnetic field, within various frequency ranges, may negatively affect the operation of electronic devices. It was found that the operation of the electronic safety systems applied at airports may be subject to interference as a result of the impact of adverse electromagnetic fields. Therefore, it is necessary to analyse the impact of electromagnetic interference on the operation of these systems. This article presents a developed author’s operation process model including electromagnetic interference within low frequencies. The reliability and operation analysis of the electronic safety systems carried out by the authors allows for numerical assessment of various types of solutions – both technical and organisational ones. As a result, they can be implemented, in order to minimise the impact of electromagnetic interference on the system functioning. This is a new approach to this issue, as there are currently designed and installed security systems at airports, but there is no analysis of the impact of electromagnetic interference on their functioning. In further research concerning this issue, the authors plan to further develop reliability-operational models, which will differentiate between the states of partial fitness. It will allow for more accurate mapping of the operation of the electronic safety systems which are applicable at airports.

Verification of measurement waveforms of transient electric field caused by micro‐gap spark using optical electric field probe

AbstractWith the widespread use of wearable terminals, machine to machine (M2M) and internet of things (IoT) equipment, electrostatic discharge (ESD: Electrostatic Discharge) due to electrification of humans and objects can cause electromagnetic interference (EMI) inside these devices, which is called intra‐EMC (Electromagnetic compatibility). This type of the EMI issue would be often derived from a steep transient electric near field generated by less than 1 kV spark discharges between micro‐gaps. To clarify the characteristics of such electric near field, therefore, an optical electric field probe, which does not disturb any electromagnetic fields to be measured, has been used to measure the transient electric field caused by a micro‐gap spark when charged metal spheres collide, while it is not fully understood whether or not the probe output precisely responds to the transient electric field in the vicinity of the discharge point. In this study, the measured waveforms of the above‐mentioned electric field are verified by comparison with the electrostatic field theoretically derived from image charges and the transient electric field calculated from an image dipole charge model combining a spark resistance law. The result reveals that at a distance near the discharge point the optical field probe does not properly work due to the presence of the electrostatic field, whereas the transient electric field at a distance away from more than twice the diameter of metal spheres from the discharge point can be correctly measured because of sufficient attenuation of the electrostatic field component.

EMI Radiation Prediction and Structure Optimization of Packages by Deep Learning

With a rapid increase in operating frequency and package complexity, conventional analysis methods cannot efficiently cope with current complex electromagnetic interference (EMI) issues. In this paper, a new method built on a deep neural network (DNN) model is proposed to accurately and rapidly predict the maximum radiated electric field at 3-meters of a wire-bond ball grid array (WB-BGA) package. The key hyper-parameters of the DNN model, such as the learning rate and type of optimizers, are discussed in depth so as to attain optimal performance. Predicted radiation results by the DNN model and the results of the full-wave simulation show good agreement. Once DNN is trained, the prediction time is in the order of milliseconds and the model size is in megabytes, which can acquire the predicted radiation quickly and accurately and save storage space. Furthermore, to prevent the radiation from exceeding requirements, package structures are optimized by adjusting those parameters sensitive to radiation and disregarding insensitive parameters. The sensitivity of these WB-BGA package structural parameters to EMI radiation can be analyzed quickly based on data with different deviations generated by the trained DNN model. The sensitive parameters are adjusted according to their correlation with EMI radiation. The effectiveness and feasibility of the optimization method are verified by the WB-BGA package with two sets of different structural parameters.

Mg0.5Zn0.5Fe2O4-polyurethane thin nanocomposite coating as broadband microwave absorber

We report the synthesis of Mg0.5Zn0.5Fe2O4 (MZF) nanoparticles by gel combustion technique followed by fabrication of thin layer (~ 100 μm) of ferrite–polymer nanocomposite on aluminum substrate and its application on broadband absorption properties over the microwave frequency range of 4–15 GHz. The particle size of ferrite powder was controlled by changing citrate to nitrate molar ratios of precursors, which exhibit different adiabatic isotherms. XRD analysis showed that ferrite phase formation occurred for all systems and the system with lowest crystallite size (~ 30 nm) was obtained for the stoichiometric citrate to nitrate molar ratio. The nanocomposite coating showed excellent broadband absorption properties with absorptivity greater than 88%. This implied that the real and imaginary part of the surface impedance values of the nanocomposite coatings are close to 377 Ω and 0 Ω respectively, which is impedance of free space over the significant region of the frequency band of interest. The stoichiometric fuel based MZF of smallest average particle size showed best microwave absorption properties. The as-developed MZF nanocomposite coating showed minimum reflection from the coating over this frequency band, which can solve various electromagnetic interference issues, stealth technology, and the radiated EMI management in on board spacecraft and several others.

Performance Analysis of Non-Isolated DC-DC Buck Converter Using Resonant Approach

DC-DC converters preserve or control the output DC voltage. Due to parasitic constituents such as leakage capacitance of both diode and inductor, and transformer leakage inductance, DC-DC converters mostly operate on rigid switching conditions which result in high switching losses. These parasitic constituents affect the dc-dc converter’s operational reliability, instigate electromagnetic interference issues and limit the converter’s operation at higher frequency operations. In this paper, resonant or soft-switch approach has been employed to improve the operating performance and design-oriented principle investigations have been carried out for overcoming the issues of parasitic constituents in 24-12V DC-DC step-down (buck) converter. This paper divulges the analysis and Matlab Simulation results for 24-12V buck converter based on resonant or soft-switching approach.

A novel hierarchically porous magnetic carbon derived from biomass for strong lightweight microwave absorption

Recent findings reveal that biomass material sometimes exhibits novel microstructure, in particular for some heterostructures and microtubular channels, which is hard to be realized by conventional chemical synthesis. Utilizing of intrinsic microstructure characteristic of biomass in nature to optimize microstructure and material component is regarded as a potential way to deal with ever-growing electromagnetic (EM) interference issue. This research taking rice as an example, a pre-treatment is conducted by dipping and annealing to obtain porous carbon and simultaneously incorporation of beneficial magnetic component. By optimizing of microstructure and material component, the fabricated hierarchically porous magnetic carbon (HPMC) material shows excellent EM wave performance with minimum reflection loss (RLmin) of −52 dB and wide effective absorption bandwidth (EAB) of 5 GHz at low filler content of 15 wt%. This work paves the way for development of biomass as a low-cost, green and renewable high-performance carbon-based absorber.

OVERVIEW OF ELECTROMAGNETIC INTERFERENCE ISSUES IN AIRCRAFT

Purpose of Study: In the modern era, due to several conflictions or uncertainty in the aircraft, Electromagnetic Interference (EMI) or Radio Frequency Interference (RFI) issues occurred, frequently. The main reason behind it several disturbances generated by an external source that imitate wireless circuits with the help of conduction, electrostatic coupling, and electromagnetic induction. These disturbances may decrease the performance of the circuits or sometimes fully stop the operations.
 Methodology: The main challenges in EMI are modeling and simulation for modern and future wireless communication systems and networks taking into account nonlinear interference effects.
 Result: In this paper, overviews of several issues of EMI or RFI are illustrated.

Development of sulfide-doped Graphene/Fe3O4 absorber with wide band electromagnetic absorption performance

Graphene has been confirmed as an ideal lightweight and high-performance electromagnetic (EM) absorber if used to deal with increasingly electromagnetic interference issue. However, the actual EM absorption performance of graphene is not desirable in a thin thickness which is due to poor impedance matching behavior and single conductive loss form. To overcome this difficulty, this research employed S doping and magnetic Fe3O4 nanoparticles loading strategies to boost EM attenuation ability by introduction of various EM loss forms, e.g. dipolar, interface, and magnetic loss ability etc. Besides, the impedance matching ability of SGN/Fe3O4 has significant improved as compared to pure graphene, primarily owing to the sharply decrease of relative complex permittivity (εr) values. The as-prepared S-doped graphene/Fe3O4 (denote as SGN/Fe3O4) absorber shows excellent wideband electromagnetic absorption property at a thin thickness of 2.0 mm which the frequency width with a reflection loss < -10 dB reach 5.3 GHz.

Development of a Measurement Apparatus for Conducted Electromagnetic Emissions

Due to the intensive dissemination of high frequency electrical and electronic systems nowadays, several issues regarding electromagnetic interference (EMI) are more and more observed in our environment. This continuous growing of EMI everywhere, can leads to a malfunction of the more susceptible electrical products and systems. In order to face this problem, one has to take into account the various aspects of electromagnetic compatibility during the design phase of electrical and electronic systems. Among the tools that can be used for this purpose, there is the impedance stabilization network (LISN) and the noise separator device. With such tools, it is possible to carry out a series of EMI measurements in the prototype phase of the product, avoiding a fail in the final test of conducted electromagnetic emissions. This paper describes the development of a low-cost LISN with support for a noise separator device, which can provide valuable information regarding common-mode and differential-mode electromagnetic noise, allowing to solve more easily EMI issues on a product or system.

Optimisation of EMI shielding effectiveness: Mechanical and physical performance of mortar containing POFA for plaster work using Taguchi Grey method

A waste material which is collected from palm oil mill called POFA is used as cement replacement in plastering work to overcome electromagnetic interference issue. This study proposes Taguchi-Grey method to assess the optimal mixtures in plastering work with multiple responses of POFA. The responses under investigation are EMI shielding effectiveness, 28-days compressive strength, 28-days flexural strength, shrinkage, slump flow, initial setting time, final setting time, water retention and air content. In the application of this method, POFA admixture percentage, topcoat powder-to-binder ratio, water-to-binder ratio, latex agent content, particle size of POFA, and curing condition are selected as control factors. From the results it had been demonstrated and verified that the optimal mixture has 20% of POFA admixture, 0% of topcoat powder-to-binder ratio, 0.6 of water-to-binder ratio, 10% of latex agent content, 140 µm of POFA particle size and with water immersion curing condition are the optimal mixture. After comparison of the verification results, the Taguchi Grey method is applicable for this study due to the confirmation result which is comparable and fulfill the standard (IEEE Std 299-1997, BS EN 998-1, ASTM C1329, ASTM C596, and ASTM C1437) requirement.

A New Soft-Switching Topology for Switched Inductor High Gain Boost

This paper proposes a new high-gain soft-switching dc–dc topology based on a switched inductor boost converter (SIBC). A conventional SIBC as a high gain boost topology has the issues of high conduction loss in switching diodes and high switching loss in the main switches. Also, it has severe electromagnetic interference (EMI) issue due to high-frequency ringing formed by parasitic inductance and diode junction capacitors. The new topology is derived with the objective of achieving zero voltage switching (ZVS) turn on of the main switch. Instead of adding extra active clamp zero voltage transition (ZVT) path at the switching node, the proposed topology augments the auxiliary ZVT path to the switching diode path. This is achieved by replacing the switching diodes with synchronous switches. The new topology can achieve soft switching for all the switches and alleviate the EMI issue. All the diodes achieve zero current switching (ZCS) turn off without reverse recovery. Auxiliary switches have ZCS turn on and ZVS turn off , and the main switches have ZVS turn on . The soft-switching SIBC also reduces the conduction loss in the switching diodes. A numerical simulation in PLECS and a prototype hardware are built corresponding to a micro-inverter application with 100 kHz switching frequency. Peak power conversion efficiency of 94.76% is achieved in the hardware prototype with Si devices.

A Voltage‐Boosting Strategy Enabling a Low‐Frequency, Flexible Electromagnetic Wave Absorption Device

Nowadays, low-frequency electromagnetic interference (<2.0 GHz) remains a key core issue that plagues the effective attenuation performance of conventional absorption devices prepared via the component-morphology method (Strategy I). According to theoretical calculations, one fundamental solution is to develop a material that possesses a high ε' but lower ε″. Thus, it is attempted to control the dielectric values via applying an external electrical field, which inducts changes in the macrostructure toward a performance improvement (Strategy II). A sandwich-structured flexible electronic absorption device is designed using a carbon film electrode to conduct an external current. Simultaneously, an absorption layer that is highly responsive to an external voltage is selected via Strategy I. Relying on the synergistic effects from Strategies I and II, this device demonstrates an absorption value of more than 85% at 1.5-2.0 GHz with an applied voltage of 16 V while reducing the thickness to ≈5 mm. In addition, the device also shows a good absorption property at 25-150 °C. The method of utilizing an external voltage to break the intrinsic dielectric feature by modifying a traditional electronic absorption device is demonstrated for the first time and has great significance in solving the low-frequency electromagnetic interference issue.