Electromagnetic Interference Problems Research Articles

Experimental electromagnetic compatibility of conducted electromagnetic interferences from an IGBT and a MOSFET in the power supply

Introduction. Most electromagnetic compatibility studies carried out in the context of power switch research are generally valid for low frequencies. This frequency restriction appears to be too restrictive for a complete analysis of the electromagnetic interference conducted. The novelty of this work lies in the load-dependent an optimal selection of IGBTs and MOSFETs for least-disturbance power switching in the frequency range from 150 kHz to 30 MHz, based on an optimal experimental selection procedure and show the impact of load value on switch switching and noise generation. Purpose. Analysis of the fundamental possibility of selecting a switching device with a power supply based on an experimental measurement which allows to increase the reliability of the entire mechanism operation and significantly simplify the design. Methods. In this paper, the proposed study is used and compared with experimental results at low and high frequencies. Then, a comparison is made for conducted electromagnetic interference (common-mode and differential-mode) generated by IGBT and MOSFET for different loads, and the proposed methodology is verified on an experiment suitable for predicting terminal overvoltage analysis and conducted electromagnetic interference problems. Practical value. The primary method for establishing a conducted electromagnetic interference source for switching devices is based on IGBT and a MOSFET depending on the resistive load. References 22, figures 17.

Implementation and analysis of a parallel kalman filter algorithm for lidar localization based on CUDA technology.

Introduction: Navigation satellite systems can fail to work or work incorrectly in a number of conditions: signal shadowing, electromagnetic interference, atmospheric conditions, and technical problems. All of these factors can significantly affect the localization accuracy of autonomous driving systems. This emphasizes the need for other localization technologies, such as Lidar. Methods: The use of the Kalman filter in combination with Lidar can be very effective in various applications due to the synergy of their capabilities. The Kalman filter can improve the accuracy of lidar measurements by taking into account the noise and inaccuracies present in the measurements. Results: In this paper, we propose a parallel Kalman algorithm in three-dimensional space to speed up the computational speed of Lidar localization. At the same time, the initial localization accuracy of the latter is preserved. A distinctive feature of the proposed approach is that the Kalman localization algorithm itself is parallelized, rather than the process of building a map for navigation. The proposed algorithm allows us to obtain the result 3.8 times faster without compromising the localization accuracy, which was 3% for both cases, making it effective for real-time decision-making. Discussion: The reliability of this result is confirmed by a preliminary theoretical estimate of the acceleration rate based on Ambdahl's law. Accelerating the Kalman filter with CUDA for Lidar localization can be of significant practical value, especially in real-time and in conditions where large amounts of data from Lidar sensors need to be processed.

Printed graphene and its composite with copper for electromagnetic interference shielding applications.

Advances in mobile electronics and telecommunication systems along with 5G technologies have been escalating the electromagnetic interference (EMI) problem in recent years. Graphene-based material systems such as pristine graphene, graphene-polymer composites and other graphene-containing candidates have been shown to provide adequate EMI shielding performance. Besides achieving the needed shielding effectiveness (SE), the method of applying the candidate shielding material onto the object in need of protection is of enormous importance due to considerations of ease of application, reduced logistics and infrastructure, rapid prototyping and throughput, versatility to handle both rigid and flexible substrates and cost. Printing readily meets all these criteria and here we demonstrate plasma jet printing of thin films of graphene and its composite with copper to meet the EMI shielding needs. SE over 30 dB is achieved, which represents blocking over 99.9% of the incoming radiation. Graphene and its composite with copper yield higher green index compared to pure copper shields, implying reduced reflection of incoming electromagnetic waves to help reduce secondary pollution.

Synthesis of Cobalt Particles and Investigation of Their Electromagnetic Wave Absorption Characteristics.

As the integration technology for integrated circuit (IC) packaging continues to advance, the issue of electromagnetic interference in IC packaging becomes increasingly prominent. Magnetic materials, acknowledged for their superior electromagnetic absorption capabilities, play a pivotal role in mitigating electromagnetic interference problems. In this study, we employed a liquid-phase reduction method. We prepared three types of cobalt (Co) particles with distinct morphologies. Through variations in the synthesis process conditions, we were able to control the aspect ratio of protrusions on the surface of the Co particles. It was found that the sword-like Co particles exhibit superior electromagnetic wave absorption capabilities, showing a reflection loss value of up to -50.96 dB. Notably, when the coating thickness is only 1.6 mm, the effective absorption bandwidth is extended up to 7.6 GHz. The spatially expansive sword-like Co particles, with their unique structure featuring dipole polarization and interfacial polarization, demonstrated enhanced dielectric and magnetic loss capabilities, concurrently showcasing superior impedance-matching performance.

A Smart Amorphous Wire Composite with Tunable Electromagnetic Shielding

Nowadays, in view of the increasingly serious problems of electromagnetic interference (EMI) and radiation pollution, smart EMI shielding materials with tunable shielding effectiveness (SE), especially “On/Off” switchable capability, are highly desirable. Herein, Co‐based amorphous wires (AWs) with excellent soft magnetic and mechanical properties are regularly arranged on a 3D‐printed mold as tunable EMI shielding composites. The EMI SE can be easily tuned in the range of ≈0.6–24.7 dB by way of rotation, which has been confirmed to be an effective way to achieve free tuning of EMI SE by simulation. In addition, by compositing AWs with reduced graphene oxide and constructing a double‐layer structure with a gap of 1/4 wavelength in the X‐band, a much wider SE tuning range of ≈1.0–57.7 dB is further realized. The representative “On/Off” switchable shielding capability that can switch between EM transmission and effective shielding, together with the wide SE tuning range larger than 50 dB, shows the great potential of Co‐based AW composites in smart EMI shielding applications.

Investigation and Analysis of Electromagnetic Interference for PWM Encoder of Urban Rail Train

Electromagnetic compatibility (EMC) is an important factor in ensuring the safe operation of the sensitive electronic equipment on urban rail trains. The pulse width modulation (PWM) encoder of an urban rail train exported from China to Brazil is sometimes affected by electromagnetic interference (EMI), which causes the train to fail to run properly. To solve this problem, the EMC test is performed on the PWM encoder to identify the coupling path and the type of interference source. The EMI coupling model and the vehicle-catenary-rail model are established by using an electromagnetic transients program (EMTP) to analyze the mechanism of interference coupling. It is shown that the unbalanced voltage of the train body caused by the backflow of the grounding current is the root cause of the interference of the PWM encoder. The maximum voltage coupled to the internal port of the PWM encoder is about 1894 V, which is sufficient to burn out the encoder. A measure to suppress the interference by installing thyristor surge suppressors (TSS) P0300SC is proposed, which effectively solves the EMI problem of the PWM encoder.

Analysis on bimodal complex permeability spectrum of a noise suppression sheet and single constituent flakes

In recent years, highly integrated active components inside small mobile communication devices have led to serious electromagnetic interference problems. The countermeasure to this problem is covering a noise source with a noise suppression sheet (NSS) which is composed of ferromagnetic flakes and polymers. The NSS absorbs effectively electromagnetic waves due to a large imaginary part of relative permeability μr″ at the specific frequency region. This function is attributed to the bimodal μr″ spectrum of NSS, but its physical origin has not been revealed so far. In this study, the bimodal μr″ spectrum of NSS has been analyzed and its physical mechanism has been discussed. The μr″ spectrum of a constituent single magnetic flake was measured by using a newly developed high-sensitivity permeability measurement system, which showed a bimodal spectrum quite similar to that of NSS. This fact indicates that the physical origin of the bimodal μr″ spectrum is attributed to the magnetization dynamics of each single constituent flake. After measuring the μr″ spectra of single flakes with various materials, such as Fe, Fe-Al, Fe-Co-V, and Fe-Si-Al alloys, these bimodal μr″ spectra were quantitatively explained by the magnetization dynamics of the flux closure states inside the flake. The magnetic domain structure of a single flake was observed by a micro-beam X-ray magnetic circular dichroism microscopy. The result confirmed that the segmented magnetic domains form the local flux closure states inside the flake.

Recent Advances in Electromagnetic Interference Suppression

With the increasing popularity and complexity of electronic equipment, the problem of electromagnetic interference (EMI) has become increasingly prominent. Such interference can seriously affect the performance, reliability, and service life of the device and, in severe cases, may cause system failure or communication interruption. Existing EMI suppression techniques are widely used to address this issue, and this paper provides a comprehensive overview. Firstly, it introduces the impact and harm of EMI on us and then presents two forms of EMI, namely conducted EMI and radiated EMI, better to understand the sources and characteristics of these disturbances. Three different EMI filters, the advantages of soft switching compared to hard switching, the working principle of random modulation, and emerging trends in electromagnetic shielding are then analyzed and discussed. Finally, we comprehensively summarize the advantages and disadvantages of the above four methods and point out the possible limitations of each technique in practical applications. We also propose potential future research directions, which will help to overcome the shortcomings of existing technologies and promote the development of the field of EMI suppression.

An efficient dual-scale method for analysis of EMI problems resulted from radiation sources

An efficient dual-scale method, which integrates parabolic equation (PE) with electric field integral equation (EFIE) formulated via the Rao-Wilton-Glisson moment method (RWG-MOM), is proposed to analyze the electromagnetic interference (EMI) problems resulted from radiation sources. This method is implemented by decomposing the original intractable multi-scale problem domain into two sub-regions: (1) modeling of the complicated ambient electromagnetic fields by PE and (2) solution of the fields coupling to the exposed electronic devices by RWG-MOM. Frequency-sweep and Fourier synthesis techniques are applied to calculate the transient currents and voltages. The proposed method is able to fully model the disturbances of the electromagnetic fields by multi-path effects. Besides, it reduces the memory footprint and the CPU computing time effectively compared to the traditional full-wave electromagnetic methods. Numerical examples are presented, and the simulation results indicate that this method is well suitable for the EMI analysis of external radiation sources.

Transparent ultrawideband polarization-insensitive absorber with optimal thickness based on a grid ITO structure

With the large-scale commercialization of broadband wireless communication technologies, interference between spatial electromagnetic waves (EMWs) is becoming increasingly serious. As devices for solving electromagnetic interference (EMI) problems, microwave absorbers (MAs) have become increasingly mature with the rapid development of artificial electromagnetic structures. However, current MAs still face challenges in terms of wideband absorption, wide-angle absorption, thickness, etc., which limits their application scenarios. Therefore, this paper proposes a transparent ultrawideband polarization-insensitive absorber based on a grid indium tin oxide (ITO) structure. This design adopts a multilayer structure with a total thickness of 3.525 mm (0.114λ L ), close to the predicted minimum thickness, to expand the bandwidth. The grid-patterned ITO film resonant structure and ITO film ground plane are designed to further improve optical transmittance by increasing duty ratios. Simulation results demonstrate over 90% absorption from 9.7 GHz to 69.2 GHz, with a fractional bandwidth (FBW) of 150.8%. The absorber has good incident angle stability and polarization insensitivity. When the incident angle varies within 0-60°, the proposed absorber maintains an absorption close to 80% over an ultrawideband range, and the absorption remains nearly constant when the polarization angle changes from 0° to 90°. The fabricated sample shows a visible light transmittance of approximately 73.2%, and shows an absorption performance consistent with simulations in the 6-38 GHz frequency range, validating the effectiveness of the proposed design. Due to its transparent, ultrawideband absorption, wide incident angle stability and polarization insensitivity properties, this proposed absorber has important guiding significance for applications in high-frequency transparent electronics, radars, communications systems and other devices working in the microwave frequency band.

A Novel Approach to Partial Discharge Detection Under Repetitive Unipolar Impulsive Voltage

Partial discharge (PD) detection is an important method to verify the reliability of the insulation structure of high voltage power electronics devices. Although there are many researches on PD detection inside power modules, they mainly focus on traditional electrical detection methods and 50 Hz working conditions, which do not meet the repetitive unipolar impulsive voltage conditions of power modules, and traditional methods cannot solve the electromagnetic interference (EMI) problem under working conditions. This paper proposes a novel approach to PD detection in power modules. This approach designs an optic fiber sensing (OFS) system based on optic theory, and conducts the detailed mathematical theoretical deduction. In addition, A partial discharge inception voltage (PDIV) signal processing method based on PD acoustic signal is proposed. Finally, the proposed approach is applied to a power module. The PD signal and PDIV is successfully captured without EMI interference and new insulation problems.

Stretchable textile with ultra-high electromagnetic interference shielding performance based on porous wrinkled conductive network

The soaring growth of flexible electronic devices has boosted the demand for electromagnetic interference (EMI) shielding materials with excellent stretchability, stability and even breathability. However, it is still a challenge to develop conductive materials with outstanding stretchable EMI shielding performance. In this work, we developed a textile with porous wrinkled conductive network through in situ polydopamine-assisted deposition of silver nanoparticles (AgNPs) on wrinkled fiber mat and polydimethylsiloxane post modification. This unique wrinkled conductive networks endows the textile with excellent electrical conductivity (103700 S/m), good breathability, superhydrophobicity, and ultra-high stretchable EMI shielding properties. The EMI shielding effectiveness (EMI SE) of the textile reaches 101.1 dB in unstretched state and still maintains at 94.1 dB at 100 % tensile strain. The superhigh EMI SE under such a high strain is much higher than the previously reported results so far. Moreover, the textile shows exceptionally good cyclic tensile durability under 100 % stain. After 1000 tensile cycles with 100 % strain, the EMI SE of sample only drops by 3.8 %. This work provides a new path for developing stretchable high EMI shielding performance materials, which is of great significance to solve the EMI problems of emerging flexible and wearable electronic devices.

Influence of focusing intensity on optically pumped metastable rare gas based on laser-induced ionization

When traditional optically pumped metastable rare gas laser (OPRGL) operating in high power output, a potential issue may arise: electromagnetic interference (EMI) caused by large volume atmospheric pressure discharge. This EMI problem imposes limitations on the application of OPRGL. We propose a new idea of preparing metastable atoms by 532 nm laser-induced preionization, which has the potential to circumvent the EMI problem. An 811.5 nm laser was used to excite the metastable (4s[3/2]2) Ar atoms in Ar-He mixture, resulting in the generation of a prominent amplified spontaneous emission (ASE) signal at 912.3 nm (4p[1/2]1→4s[3/2]2). By investigating intensities of the 912.3 nm fluorescence and ASE as a function of the delay time between 811.5 nm and 532 nm lasers, the influence of the 532 nm laser's focusing intensity on the evolution of prepared metastable atomic concentration was unveiled, as well as the amplification mechanism of 912.3 nm signal. Furthermore, the competition mechanism between ASE and the fluorescence channels originating from the 4p[1/2]1 level was studied. Considering the influence of plasma expansion on metastable atomic concentration, as well as the influences of threshold, gain and gain length on ASE, at the “photoexcitation + radiation + collisional relaxation” stage, we obtained a reliable effective lifetime of the metastable 4s[3/2]2 level through analysis of the decay curve of the 912.3 nm ASE intensity. Similarly, in the “ion-electron recombination” stage, a reliable effective lifetime of the metastable 4s[3/2]2 level was obtained by analyzing the decay curve of the 912.3 nm fluorescence intensity. Additionally, the 912.3 nm ASE pulse width was influenced by various factors, including the effective lifetime of the 4p[1/2]1 level, the concentration of metastable Ar, the plasma expansion rate, and the gain length, etc. This work demonstrates that OPRGL based on laser-induced preionization offers a promising alternative for the future advancement of OPRGL.

The Effect of Conducted Emissions of Grid-Tied Three-Phase Adjustable Drives

Electromagnetic Interference (EMI) is generated and mitigated in power converters. EMI problems are related to high-speed power converters. This article focuses on conducted electromagnetic interference in adjustable-speed drive (ASD) systems. The electromagnetic compatibility of three-phase/level grid-connected drive inverters is investigated. The test setup is built per the CISPR16-1–2 standard, and the interferences produced from the inverter to the grid are measured. The main dependencies of conducted emissions of a power inverter, changes in the length/shape of main cables, and motor speed have been investigated under load and no load conditions. Factors affecting EMI performance and filter design issues will be addressed. A statistical approach to quantifying the frequency domain impact of conducted emission noise created on the three-phase system by operating various emission sources. Fast Fourier Transform (FFT) was applied for time–frequency domain conversion, and to evaluate with a statistical approach Minitab software was used. Then, a filter design is created to prevent these interferences from being conducted to the grid. Also, the noise attenuation of the EMI filter has been validated in the simulation. Briefly, this study fills in the blanks of uncertainties involved in measuring three-phase emissions, which helps the engineers at the design stage of three-phase converters.

Electromagnetic disturbance characteristic of typical high voltage switchgear interruption process in offshore wind farm based on integrated conduction model

AbstractIn an offshore wind farm, a high‐voltage switchgear interruption in an offshore substation creates a high‐frequency, high‐amplitude overvoltage that can cause severe electromagnetic interference problems in the intelligent electronic device. To address this issue, mathematical models, vector fitting and finite element method were used to build an integrated electromagnetic disturbance conduction model, whose accuracy was verified by large current interruption tests. Through the simulation of a typical offshore wind farm's single‐phase grounding fault interruption process, the electromagnetic disturbance characteristics and the impact of the ground position are obtained. The results show that during the fault interruption process of phase B grounded, the dominant frequency of disturbance voltage can reach 4.34 MHz, and the amplitude can reach 1.12 kV. The ground grid has a large impact on the interference voltage, which can reach a maximum value of 2.28 kV under specific conditions. The disturbance voltage in the fault process mainly comes through the current transformer, while during the interruption process, it mainly comes through the ground grid. The authors provide a method to establish the integrated electromagnetic disturbance simulation model, which can improve the accuracy of the electromagnetic disturbance conduction process simulation of intelligent components.

Recent progress on the electromagnetic wave absorption of one-dimensional carbon-based nanomaterials

The rapid development of electronic information technology and the use of high-power electrical equipment have led to the increasingly serious problem of electromagnetic interference (EMI). Therefore, it is of great significance to study electromagnetic wave absorbing (EWA) materials with good absorbing properties. Compared with other wave absorbing materials, carbon-based nanomaterials such as silicon carbide (SiC), carbon nanotube (CNT), carbon nanowire (CNW) and carbon nanofiber (CNF) have the advantages of low density, large specific surface area/aspect ratio and excellent dielectric properties, which make them stand out. However, impedance mismatch caused by high conductivity and a single microwave loss mechanism seriously affect the absorption performance. In order to overcome the above shortcomings, surface modification, component control, structural design and other methods have been widely used in EWA materials in recent years to improve their absorption performance. In this review, we introduce the mechanism of microwave absorption and summarizes the research progress of one-dimensional carbon based nanomaterials and their composites. The preparation methods and microwave absorption properties of one-dimensional carbon based nanocomposites with different components, morphologies, and microstructures were discussed in detail. Finally, the challenges and future development prospects of one-dimensional carbon based nanomaterials were summarized, providing reference for the development of high-performance microwave absorbing materials.

Recent Progress in Electrically Conductive and Thermally Conductive Lubricants: A Critical Review

Electrically as well as thermally conductive lubricants have drawn considerable attention and are an emerging research topic because they have unique advantages and advanced lubrication performance over traditional lubricants such as corrosion protection and efficient heat dissipation. For instance, some components of electric vehicles (EVs) such as bearings, seals, pads and gears require conductive lubricants to avoid premature failure and electromagnetic interference (EMI) problems due to induced shaft voltages and currents. This review provides a comprehensive overview of the recent developments in conductive lubricants. The review focuses on the important aspects to enhance the thermal and electrical conductivities as well as the tribological behavior (COF, and wear rate) of conductive solid, semisolid, and liquid lubricants. The lubricants that are electrically and thermally conductive with superior tribological performances have been identified through extensive literature review and presented in tabular form. This review summarizes the effect of various additives used to improve the conductive properties of the lubricants, such as polyalphaolefin oil, hydraulic oil, paraffin oil, and mineral oil. Furthermore, the review discusses the lubricating mechanism of conductive solid and liquid lubricants to facilitate a deeper understanding. Finally, the future perspectives and the research directions for conductive lubricants are also addressed.

Transmission Attenuation Evaluation of Noise Suppression Sheet for 5G and Beyond

To support the development of smart technology, such as the Internet of Things, smart devices, and smart manufacturing, 5G and beyond mobile communication systems will utilize higher frequencies. Accordingly, the number and types of network devices will increase, and how to suppress electromagnetic interference in such small wireless communication terminals will be an important issue. As one of the essential technologies, a noise suppression sheet needs to be developed to minimize electromagnetic interference problems in the new frequency bands. Here, we have developed a method to evaluate the transmission attenuation characteristics of noise suppression sheets up to 60 GHz, with reference to the IEC standard (IEC62333-2: below 6 GHz). To confirm its practicality, a systematic demonstration was performed by measuring commercially available noise suppression sheets under various conditions. The mechanism of the transmission attenuation effect in a wide frequency range, including an unexpected effect due to surface modes, is investigated based on material properties and electromagnetic simulations.

MoBiSea: A Binary Search Algorithm for Product Clustering in Industry 4.0

Proprietary systems used to modernize Industry 4.0 usually involve high financial costs. Consequently, using low-cost devices with the same functionalities, capable of replacing these proprietary systems but at a lower cost, has become an incipient trend. However, these low-cost devices usually come with electromagnetic interference problems as they are encapsulated in electrical panels, sitting alongside electromechanical devices. In this article, we present Mode Binary Search, an algorithm specifically designed for use in a low-cost automated-industrial-productivity-data-collection system. Specifically, productivity data are obtained from the availability and sealing signals of the thermoplastic sealing machines in production lines belonging to the agri-food industry. Mode Binary Search was designed to cluster sealing signals, thus enabling us to identify which products have been made. Furthermore, the algorithm determines when the manufacturing of each product starts and ends, in other words, the exact moment a product change occurs and all this without the need for operator supervision or intervention. Finally, we compared our algorithm, based on binary search, with three clustering mechanisms: k-means, k-rms and x-means. Out of all the cases we analyzed, the maximum error committed by Mode Binary Search is limited to 2.69%, thereby outperforming all others.

Dual randomized discontinuous pulse width modulation for three-phase inverter

ABSTRACT The discontinuous PWM technique, with its advantage over the continuous PWM technique in reducing switching losses in power converters, is gaining popularity. However, its deterministic nature results in discrete harmonics with significant amplitudes, which leads to electromagnetic interference (EMI) emissions. The randomised PWM technique is gaining more interest because of its effectiveness in spreading the harmonic spectrum and thus reducing EMI problems in power converters. This paper presents a carrier-based dual randomised discontinuous PWM (DRDPWM) method for a three-phase voltage inverter. The DRDPWM method combines the random carrier frequency (RCF-DPWM) and random pulse position (RPP-DPWM) schemes. In addition to reducing switching losses, DRDPWM can achieve a broad spread of the voltage spectrum with significantly smaller amplitudes. Furthermore, it produces less inverter output current distortion when compared to traditional DPWM and simple random (RCF-DPWM and RPP-DPWM) schemes. Simulations and experimental results confirm the effectiveness of the suggested method for spreading the voltage spectrum compared to simple random schemes. Additionally, an evaluation of the performance of all randomised discontinuous schemes is conducted based on a number of assessment metrics, including the switching loss factor (SLF), the power spectral density (PSD), the harmonic spread factor (HSF), and the quality factor (QF).