Electromagnetic Disturbances Research Articles

Quick and Automatic Solution of Electromagnetic Disturbance by Using the Intelligent Noise Filter

Quick and Automatic Solution of Electromagnetic Disturbance by Using the Intelligent Noise Filter

Electromagnetic Risk Analysis for EMI Impact on Functional Safety With Probabilistic Graphical Models and Fuzzy Logic

For the functional safety of complex systems such as road vehicles, sufficient immunity of the safety-related electronic, electrical and programmable electronic systems to the anticipated electromagnetic environment is required. Current rule-based practices follow established standards for testing the immunity and emission performance at vehicle and sub-system levels. Nonetheless, with increasingly rapid technological changes, confidence may not be sufficient even if the immunity test levels or the number of tests is increased. A risk-based EMC approach, on the other hand, aims to identify the safety hazards due to electromagnetic disturbances and mitigate the associated risks to achieve the required confidence level. Traditional tools used for risk analysis (such as fault tree analysis, event tree analysis and failure mode and effect analysis) may not be sufficient as the complexity level increases. In this letter, a graphical approach is proposed to enable system visualization as well as supporting a comprehensive risk analysis. The possible implementation of a system-level analysis is illustrated with several methods (e.g., Bayesian networks, Markov random fields and fuzzy set theory). These methods could be used to include EM risk factors such as spatial location, functional dependence etc. in order to estimate the risks associated with EMI-related hazards.

Two VHDL-AMS-based models of multi-conductor power cables for EMI simulations

Due to the fast switching of the commutation cell in a motor drive system, high-frequency electromagnetic disturbances propagate through cables to reach the loads. Mismatched impedances lead to an overvoltage at the loads terminals. In order to study this EMI issue, accurate circuit models of power cables are required. In this context, this paper proposes two multi-conductor cable models. Our approach takes into consideration the frequency dependence of the cable per-unit-length parameters, the coupling between conductors and propagated induced phenomena. The power cables used in motor drive systems are characterized by their rotational symmetry. Thus, the complexity of the model is reduced by means of both a set of mathematical functions approximating the frequency behavior of the cable and using a modal domain-based transfer matrix. So, the VHDL-AMS frequency model can be easily deduced. Once the model is established, the simulation of any cable length becomes an easy task. The model is implemented in ANSYS Simplorer software. After that, the time domain model is built up based on the vector-fitting algorithm. In order to validate our proposal, a comparison of the common mode and the differential mode frequency responses of the reduced cable model with those of the well-known cascaded cell model and measurements found in the literature is performed. The results demonstrate the accuracy and the speed of our approach in the predefined frequency range. Also, a time-domain comparison between the frequency model and the time model is performed. The results obtained validate the two models.

Nonlinear propagation of low‐frequency electromagnetic disturbances in plasmas

AbstractElectromagnetic (EM) waves/disturbances are typically the best means to understand and analyse an ionized medium like plasma. However, the propagation of EM waves with a frequency lower than the plasma frequency is prohibited by the freely moving charges of the plasma. In dense plasmas, though the plasma frequency can be typically quite high, EM sources at such higher frequency are not easily available. It is, therefore, of interest to seek possibilities wherein a low frequency (lower than the plasma frequency) EM disturbance propagates inside a plasma. This is possible in the context of magnetized plasmas. However, in order to have a magnetized plasma response in high‐density plasmas, one requires an extremely strong external magnetic field. In this manuscript, it is demonstrated that the nonlinearity of the plasma medium can aid the propagation of a slow (effective frequency lower than the plasma frequency) EM wave inside an overdense plasma. A possible mechanism of guiding, collimating, and trapping of the EM pulse or electron current pulses by appropriate tailoring of the local plasma density profile is also shown. Certain interesting applications of the propagation of such slow EM pulse through the inhomogeneous plasma is also discussed.

Reducing the Functional Safety Risks (and Other Risks) That Can Be Caused by EMI — New IEEE Standard 1848

When Functional Safety risks must be reduced throughout the lifecycle of an electronic system, the acceptable levels for the risks that could be caused by electromagnetic disturbances or electromagnetic interference (EMI) are about 100dB lower than normal for immunity tests. This means that these risks are incapable of being verified or validated by immunity testing only. At the time of writing, IEEE Standard 1848 is well on its way towards being published. This is a new type of IEEE Standard, and will provide requirements and guidance on the use of well-proven techniques and measures to help ensure that neither electromagnetic disturbances nor EMI will be the cause of unacceptable Functional Safety risks. Its techniques and measures cover: project management; system design; operational design of hardware and software; verification, and validation. They also cover assembly/installation; commissioning, maintenance; upgrade; refurbishment, and disposal. Although intended for reducing Functional Safety risks, the techniques and measures in IEEE 1848 can also be used for reducing any quantifiable risks (mission-critical, reputational, financial, etc.) that could be caused by electromagnetic disturbances or EMI.

Challenges and prospects of machine learning in visible light communication

Visible light communication (VLC) is a promising research field in modern wireless communication. VLC has its irreplaceable strength including rich spectrum resources, no electromagnetic disturbance, and high-security guarantee. However, VLC systems suffer from the non-linear effects that exist in almost every part of the system. As a part of artificial intelligence, machine learning (ML) is showing its potential in non-linear mitigating for its natural ability to fit all kinds of transfer functions, which may dramatically push the research in VLC. This paper introduces the application of ML in VLC, describes five recent research of deep learning applications in VLC, and analyses the performance.

Analysis of Propagation Characteristics of Electromagnetic Disturbance from the Off‐Line of Pantograph‐Catenary in High‐Speed Railway Viaducts

Pantograph arcing caused by Off-line of pantograph-catenary (OLPC) will generate Electromagnetic disturbance (EMD), which will affect train control system and communication system. This paper proposes a simplified model of the train and pantograph to investigate propagation characteristics of EMD from OLPC in the viaduct scenario, containing attenuation law in transverse and longitudinal directions. As a result, the electric field strength of EMD from OLPC increases with distance in transverse direction from 10m to 30m in the viaduct scenario, which is different from the ground scenario. The fitting formulas are found to research the attenuation law at different frequency points. We get the conclusion that the limit and measurement distance is not applicable for the viaduct scenario in current standard. To prove this, measurement in the viaduct scenario is completed, and the plausible evidence to explain the result is discussed. These results are useful in the measurement of radiated emissions, on-board equipment layout and the research of standard in high-speed railway.

Electromagnetic Disturbance Characteristics and Influence Factors of PETT Oscillation in High-Voltage IGBT Devices

Plasma extraction transit time (PETT) oscillation occurs when insulated gate bipolar transistor (IGBT) devices turn off, whose frequency can reach hundreds of MHz. This high-frequency oscillation can induce electromagnetic interference problems and may exceed relevant IEC limits for electromagnetic emission. As one of the electromagnetic disturbance sources from internal IGBT, the PETT oscillation has not attracted much attention in the electromagnetic compatibility (EMC) problems of application and development of high-voltage IGBT devices yet. In this article, the detailed characteristics of PETT oscillation, i.e., oscillation frequency, duration time, and oscillation peak, in high-voltage IGBT devices are systematically investigated by experiments. From the results, oscillation frequency increases with the increase of reverse voltage, whereas decreases with the increase of the temperature. Then, more complex dependencies of the PETT oscillation characteristics on IGBT's commutation conditions are presented. It is shown that its characteristics vary greatly under different reverse voltage, forward current, and temperature. The hazard of PETT oscillation to electronic components is discussed as well. PETT oscillation occurs during the turn-on process, which is first reported. Based on the experiment results, the EMC test related to PETT oscillation is suggested to be performed under different commutation conditions.

Response of 10-kV Metal-Oxide Surge Arresters Excited by Nanosecond-Level Transient Electromagnetic Disturbances

Nanosecond-level transient electromagnetic disturbance (TED), including very fast transient overvoltage caused by operation of disconnectors, high-altitude electromagnetic pulse, and many other fast transients may interfere or even damage the electrical equipment. As one of the main overvoltage protective equipment, the protective performance of metal-oxide surge arresters (MOAs) under nanosecond-level TED should be investigated and then compared with that under microsecond-level TED, especially the lightning impulse. Based on a testing platform containing a 400-kV pulse generator with adjustable rise time from 5 to 100 ns, the behaviors of nonlinearity, fast impulse response, and converting impedances of three types of 10-kV MOAs under TED with different rise time were explored experimentally in this article. The peak residual voltages of 10-kV MOAs under TED with the rise time of 5 ns at 5 kA are 50.2-60.7% higher than those under the lightning impulse. The rise time of TED has significant influence on the peak voltage and impedance converting behaviors of MOAs. A circuit model of 10-kV MOAs under nanosecond-level TED is built and validated by experimental results, which can be applied in insulation coordination and design of protective devices against TED.

Effectiveness of a Matched Filter to Cope With Harsh Phase and Amplitude Modulated EMI

This article investigates the effectiveness of a matched filter to cope with continuous wave electromagnetic disturbances that are phase and amplitude modulated from wireless systems, e.g., binary phase shift keying and quadrature amplitude modulation. A wired communication channel between sender and receiver that uses nonreturn-to-zero-level data encoding is disturbed by those nearby wireless systems. A matched filter is used on the wired communication channel to filter out the additional unwanted wireless disturbance. The bit-error rate (BER) is calculated after filtering and decoding the received voltages and is used as a metric to compare different kinds of disturbances and different levels of sampling frequency. The results show that the matched filter is very effective when the carrier frequency of the disturbance is equal to an integer multiple of the bit frequency and when not equal to the sampling frequency. This sampling frequency is determined by the bit rate of the desired signal and the oversampling factor on which the matched filter is based. Finally, the filter gain at a BER of 0.1% is determined. This gain shows that an oversampling of 4 times per bit and using a matched filter already results in an average filter gain of 10–15 dB.

The Use of PMU Data for Detecting and Monitoring Selected Electromagnetic Disturbances

The Use of PMU Data for Detecting and Monitoring Selected Electromagnetic Disturbances

High Directivity Reference RF Source and its Radiated Emission Model for Site Correlation

This article presents a configurable high directivity radio frequency reference noise source and its radiated emission (RE) simulation model. This noise source is a representative of actual programmable logic controller (PLC) and input output (IO) products with a high-speed gigabit backplane. It is designed to produce a reference noise signature from 30 MHz to 6 GHz with RE levels close to the class A electromagnetic radiation disturbance limits of CISPR 11 and CISPR 22. An RE model f this noise source was established to investigate the design factors. Multiple emissions' scans were performed in two separate semianechoic chambers located in different facilities in order to test the repeatability of this noise source. The measurement results indicated that the noise source has very good repeatability and that it can serve as a reference noise source. The results were also used to evaluate the maturity of the simulation technology as well as to quantify the difference between chambers.

Все пандемии мира: их космическая обусловленность и прогнозирование

Currently, there is an unprecedented struggle among epidemiologists to create reliable means of protection against the new deadly corona-virus disease "COVID-19"that has engulfed human civilization. The situation is complicated by the lack of a clear understanding of the physical nature of viral epidemics and pandemics. The article based on the "space wave electromagnetic resonance concept" developed by the authors shows that the most likely cause of the corona virus pandemic, as well as most of the major pandemics of the past, were powerful electromagnetic and gravitational disturbances coming from Space.

10-kV Transmission Line Experimental Platform for HEMP Immunity Test of Electrical Equipment in Operation

To investigate the high-altitude electromagnetic pulse (HEMP) immunity of electrical equipment in operation, a 10-kV transmission line (TL) experimental platform is built in this paper. The conducted transient electromagnetic disturbance (TED) could be injected to the electrical equipment of 10-kV TL with power on or power off. The TED is produced by the pulsed current injection (PCI) generator, whose rise time is less than 20 ns and full width at half maximum is in the range of 500 ~ 550 ns on short-circuit state with 60 Ω resistor. On the other hand, the 10-kV TL is equivalently designed in cross section to make its characteristic impedance being 330 Ω to conform to the value of practical case. The voltages and currents applied on the tested equipment can be measured at nano-second level simultaneously, which are of great use to learn the effect mechanisms and compare the results under different working conditions. Some 10-kV pin-type porcelain insulators are tested under different conditions, which shows the capacity of the proposed platform to test immunity of 10-kV electrical equipment.

The kinetic inductance of single-walled carbon nanotube metal type

The results of theoretical studies of the kinetic inductance Lk metallic single-walled carbon nanotube type, taking into account the electron-electron interaction in the approximation of a right circular cylinder are presented. The system under consideration is a cylindrically symmetric potential well with a final height of the wall. As part of the response of the theory of two-dimensional electron gas in the external electromagnetic disturbance obtained in the form of kinetic inductance depending on the nanotube diameter, frequency and intensity of the radiation. Established that Lk value increases with increasing frequency, and decreases with increasing radiation intensity.

Predictive Analysis for Radiated Electromagnetic Disturbance in MMC-HVDC Valve Hall

The radiated electromagnetic interference (EMI) in the valve hall of the modular multilevel converter (MMC) station must be limited below a certain value to ensure the normal operation of the equipment and the safety of the engineers. In this paper, a method for predicting the radiated EMI is proposed, which takes all the necessary factors, such as the physics-based characteristics for IGBT module, sub-module topology, and converter space structure into consideration. This method involves the improved physical model of semiconductor devices, which discards the non-physical feedback parameter introduced by some previous research. At the same time, through the decoupling of the submodule and the bridge arm circuit, the order of the large-scale system is reduced so that the sub-modules can be calculated in parallel, greatly reducing the overall calculation burden of the model and accelerating the nonlinear small time-step simulation. The wideband characteristics of the converter valve tower are fully considered, with each of the bridge arms regarded as a two-port network with independent sources. The parameter integration and distribution process can also achieve complete parallel calculation. The converter valve tower is modeled as a complex antenna structure with the output voltage of each sub-module as the excitation, the calculation of near-field radiation intensity for the converter valve tower is performed in Alteir FEKO. The measurement conducted inside an actual 49-level converter station verifies the accuracy of the model.

A Fully Coupled Numerical Method for Coated Conductor HTS Coils in HTS Generators

Superconducting rotational generators are a promising application of the high temperature superconductor (HTS). Typically, superconducting rotating generators use HTS coated conductors to form the DC coils in the rotor as they experience lower AC loss compared to the stator windings. However, in the actual operation, the AC loss produced by the harmonic magnetic field is inevitable. Other transient electromagnetic disturbances in the operating generator environment can also cause the AC loss. This paper introduces a fully coupled numerical method for coated conductor HTS coils in operating generators based on the T-A formulation, which is verified by almost the same simulation results with the A-H formulation model. Using this method, the simulation results show that the ferromagnetic stator teeth will increase the AC loss caused by the harmonic magnetic field and the load change, while the shielding layer can decrease the AC loss in a certain amount.

Chosen Aspects of the Electromagnetic Compatibility of Plasma Reactors with Gliding Arc Discharges

This paper presents an analysis of electromagnetic disturbance interactions inside the three-phase gliding arc plasma generation installation. This is the main part of the electromagnetic compatibility analysis of the reactor installation. All elements of the nonthermal plasma installation are described from the point of view of disturbance generation and their influence on the power supply system. The analysis is based on the results of tests carried out in accordance with the guidelines of the electromagnetic compatibility (EMC) Directive and harmonised standards. The disturbances measured are large, over 20 dB above the limits. The disturbances measured allow valid conclusions to be reached in relation to this type of installation. The implication is the need for plasma reactors designed with elements that reduce radiated and conducted interference.

Individual emission assessment of electromagnetic disturbances based on aggregated data

Individual emission assessment of electromagnetic disturbances based on aggregated data

Make invisible visible: to the guaranteed signal averaging for the distributed fiber sensor

Fiber-optic sensors are becoming wide spreading in many fields due to a lot of advantages such as high spatial resolution, small size, immunity to the electromagnetic disturbances and possibility of multiplexing. Many benefits are fundamentally unattainable for electrical sensors by the physical operation principles. The processing of signals received from the optical fiber temperature sensor is considered. Raman sensor provides high spatial resolution. The main problem of signal processing for the temperature calculating is a large noise arising from the low level of current received from opto-converter. A method for estimating the additive noise level is presented based on calculation of the standard deviation. Comments concern the multiplicative noise during the rise and fall of the signal are given. Possibilities of guaranteed identification of DTS signals based on experimental measurement of statistical characteristics and representation it as so-called potential characteristic is evaluated. The signal-to-noise ratio may be increased by averaging the potential characteristics.