Conductive Electromagnetic Interference Research Articles

Analysis of Electromagnetic Interference for Anti-Medal UHF RFID Temperature Tag in High Power Electronic Equipment

Being inches from the rapid development of new energy technology, the capacity of high-power power electronic equipment is increasing rapidly, and the requirements for its safe and reliable operation are also rising. As a result, the demand for online temperature monitoring of such equipment is becoming increasingly urgent. RFID temperature measurement technology can be used for real-time monitoring of the temperature of powered operation equipment. However, the operation of high-power electronic equipment generates strong electromagnetic interference, which can seriously affect the normal operation of RFID temperature measurement systems. For applications involving the internal temperature measurement of high-power power electronic equipment, this paper employs an RFID anti-metal temperature tag antenna with a short-circuit cutoff structure. This structure was tested in an excitation switchgear cabinet. During the low-power operation of the cabinet, the temperature tag functioned normally. By combining an RFID antenna model with an electromagnetic interference simulation model of the main circuit of the excitation switchgear cabinet, this paper establishes an electromagnetic interference simulation model for an RFID temperature tag. It analyzes how the tag’s antenna performance parameters change when subjected to interference. Through simulation, the failure mechanism of the RFID temperature tag during the high-power operation of the excitation switchgear cabinet is clarified. The analysis found that there are both conductive electromagnetic interference and radiated electromagnetic interference in the excitation switchgear cabinet, with the conductive electromagnetic interference having a more significant effect. Conductive electromagnetic interference can seriously impact the performance of RFID temperature tags in the excitation switchgear cabinet, significantly degrading their performance. In contrast, the effect of radiated electromagnetic interference on the tags is relatively small. Therefore, this paper employs anti-metal RFID temperature tags and simulates and analyzes their electromagnetic interference characteristics.

Conductive fabrics based on carbon nanotube/Ti3C2Tx MXene/polyaniline/liquid metal quaternary composites with improved performance of EMI shielding and joule heating

Developing lightweight, flexible, conductive electromagnetic interference (EMI) shielding textiles with highly thermal conductivity and Joule heating performance is of great urgency in the field of next generation of wearable electronics, thermal management, communication, and artificial intelligence. In this work, an effective strategy to construct conductive fabrics based on carbon nanotube (CNT)/Ti3C2Tx MXene/polyaniline (PANI)/liquid metal (LM) quaternary composite with improved performance of EMI shielding and Joule heating is proposed. Conductive fabrics decorated with CNT/Ti3C2Tx/PANI/LM (CTPLM) as the conductive slurry by a simple solution dip-coating technique demonstrate a remarkable EMI shielding efficiency (EMI SE) of 78.9 dB at the thickness of 0.27 mm as well as absorbing shielding effectiveness (SEA) of 64.4 dB in the range of 8.2–12.4 GHz. The synergistic effect of high electrical conductivity and porous structure endow CTPLM-CF textiles with significantly higher EMI SE than pristine MXene film and pure CNT layer. Moreover, EMI shielding performance can be further improved to 104.3 dB when three layer conductive fabrics are combined. At the same time, conductive textiles present superior Joule heating performance with a saturation temperature of 34.5 °C @1V, 94.3 °C @2V, and 130.2 °C @3 V after 60 s, respectively. The combination of these components could comprehensively utilize the low density of carbon materials and excellent electrical conductivity from MXene and LM, thus providing a lightweight, flexible, multifunctional conductive textiles with superior EMI shielding and efficient Joule heating capability, which is highly desired for applications in aerospace, intelligent electronics, wearable electronics, thermotherapy, and personal self-heating system in harsh environment.

Electromagnetic Compatibility of Compensating Devices and Converters of an Adjustable Electric Drive in Electrical Networks of Industrial Enterprises

The problems of reactive power compensation and improving the quality of electrical energy in the power supply systems of industrial enterprises are inseparable. Their relevance is due to the widespread use of electric receivers that consume reactive power and distort the quality of electrical energy in the network, as well as the implementation of new technologies, systems and equipment into production that make increased demands on the quality of electrical energy consumed. An important characteristic of the quality of electrical energy rationed by GOST 32144–2013 is the non-sinusoidal voltage. The main reason for the non-sinusoidal voltage in the electrical networks of industrial enterprises is the use of electrical equipment with a nonlinear voltage characteristic, which is a source of conductive electromagnetic interference, in particular: adjustable DC and AC electric drives, uninterruptible power supplies of electric receivers, electric welding equipment, electric arc furnaces, induction heating installations, gas-discharge radiation sources. Due to the nonlinearity of the current-voltage characteristics, the above devices consume a non-sinusoidal current from the network, which causes harmonic distortion of the supply voltage, including the fundamental harmonic component and higher harmonic components that are multiples of the fundamental frequency. Non-sinusoidal voltage, in turn, causes additional losses of power and energy in the elements of the electrical network, causes overheating and accelerated aging of the insulation of electrical equipment, reducing its operational reliability and reducing service life, worsens the accuracy of electrical measurements, causes malfunctions in automation systems, telemechanics, relay protection, electronic systems and communications. Non-sinusoidal voltage significantly complicates the compensation of reactive power in the electrical network. Compensating devices are made on the basis of capacitors, whose electrical parameters (resistance, power, current) depend on both the magnitude of the supply voltage and its harmonic composition. The present article identifies problems and proposes solutions in terms of reactive power compensation and improving the quality of electrical energy in electrical networks containing thyristor voltage converters and frequency converters used in adjustable electric drive installations of industrial enterprises.

Prediction and Analysis of Conduction Electromagnetic Interference in Communication Power

Conducted electromagnetic interference (EMI) in power electronic equipment is an important factor restricting the development of power electronics technology, and the research is of great hot and difficulty. The prediction of conducted EMI is to effectively guide the design of EMI filters. On the one hand, the selection of commonmode capacitance and inductance values can be guided by the analysis of propagation path impedance; on the other hand, various passive devices are analyzed by simulation the influence of parasitic parameters on conducted EMI can guide the selection of filter capacitors and inductors. In this paper, we take the widely used switching power supply as an example, a novel EMI conduction modelling is proposed, the impedance analysis method is used to model the high-frequency parasitic parameters, the model was built for predicting the conducted EMI accurately of switching power supply.

Highly conductive graphene film with high-temperature stability for electromagnetic interference shielding

Lightweight, flexible and highly conductive electromagnetic interference (EMI) shielding materials are urgently needed to protect the electronic and telecommunication devices from interference failure. Carbon-based films have attracted much interest to provide EMI shielding with minimal thickness in recent years, particularly exemplified by macroscopic graphene film. However, the inferior electrical conductivity to metal or the un-stability of doped graphene film cannot meet the ever-growing demands for harsh environment applications. Here, we prepare highly conductive copper chloride intercalated graphene film (GF-CuCl2) with high-temperature stability up to 400 °C. The intercalation of CuCl2 significantly improves the hole density, and the achieved electrical conductivity (1.09 × 107 S m−1) is nearly 10 times that of pure graphene film. The ultra-low temperature coefficient of resistance (4.31 × 10−4 K−1) makes GF-CuCl2 electrically stable over a broad temperature range. A 35-μm-thick GF-CuCl2 exhibits an average EMI shielding effectiveness of ∼110 dB from 2 to 18 GHz and ∼126 dB from 8.2 to 12.4 GHz, which is the highest among materials of comparable thickness. Moreover, the EMI shielding capability of GF-CuCl2 shows long-term durability under extreme conditions. All these characteristics demonstrate the GF-CuCl2 is suitable for the practical EMI shielding applications.

Flexible thermoplastic polyurethane-carbon nanotube composites for electromagnetic interference shielding and thermal management

• Flexible TPU composites were prepared by NIPS assisted solution mixing method. • Long length MWCNT composites offer a remarkable EMI SE value of 42.5 dB. • Short length MWCNT based composites exhibit excellent thermal management. • Short length MWCNT based composites possess good electromechanical performance. Lightweight, flexible, and thermally conductive electromagnetic interference (EMI) shielding materials have garnered front facet research interest because of urgent demand to address the EM wave pollution. Herein, inspired from the effectiveness of interconnected networks of different types of carbon nanotubes (CNTs), an endeavored to design three types of CNTs based thermoplastic polyurethane (TPU) composites through a facile solution blending with non-solvent induced phase separation (NIPS) strategy. The effect of different length of CNTs on the EMI shielding, electrical and thermal conductivity performance of TPU nanocomposites have been studied explicitly. The composite with long length CNT (10 wt%) offered a remarkable EMI shielding efficiency of 42.5 dB, the electrical conductivity of 1.9 × 10 −3 S/cm, whereas composite with short length CNTs showed a thermal conductivity of 0.51 W/mK and the corresponding thermal conductivity enhancement efficiency exceeded 145% relative to pure TPU. Incorporation of long length CNTs helped to form unique interconnected conductive networks within the TPU matrix that boost more the electron or charge transferability inside the composites, improvement in mechanical properties, EMI shielding, and electrical properties than that of short length CNTs. In contrast, short length CNTs display significant electromechanical performance and heat transferability than that of long length CNTs. The composites showed a high response in electrical conductivity and minor change in EMI shielding efficiency with repeated bending cycles. This work provides a corelated remark of different types of CNT based TPU composites for superior EMI SE and thermal management applications for next generation wearable and stretchable electronics.

ОСОБЛИВОСТІ ВИМІРЮВАННЯ ТА ЕФЕКТИВНОГО ПРИТЛУМЛЕННЯ НАПРУГИ КОНДУКТИВНИХ ЕЛЕКТРОМАГНІТНИХ ЗАВАД ВІД ТРАНЗИСТОРНИХ ПЕРЕТВОРЮВАЧІВ НАПРУГИ

The paper considers voltage converters as sources of conductive electromagnetic interference (EMI). Some features of the standard measurement method of converters EMI are considered and it is shown that it measures only the total level of noise, which can be the same at completely different relations between the differential and common components of EMI. This leads to inefficient use of means reducing the total converter noise to the permitted level, because the different ratio between the above components of this noise requires different means to reduce them. The paper proposes to supplement the standard noise measurement method by two additional measurements at frequencies where the total noise exceeds the permitted level, using during the first measurement the additional RFI common mode filter which effectively reduces only the common noise, and the additional RFI differential mode filter which effectively reduces only the differential noise during the second measurement. It is shown that these two additional measurements make it possible to determine the differential and common components of the total noise. This, in turn, makes it possible to reduce the total noise to the permitted level at the minimal cost. References 6.

Estimation of Parasitic Capacitance of Common Mode Noise in Vehicular Applications: An Unscented Kalman Filter-Based Approach

Parasitic capacitance has a considerable impact on conductive electromagnetic interference (EMI), especially on the common mode (CM) noise. In vehicular applications, such as more electric aircraft and electrical vehicles, the value of CM stray capacitance can vary during the drive cycle, due to some change in environmental, and operating conditions, resulting in fluctuations in EMI level. Designing EMI filters according to potentially overestimated CM capacitance results in additional weight, volume, and cost which should be avoided. In this paper, for the first time, the parasitic capacitance relevant to CM noise is estimated in real-time using unscented Kalman filter (UKF). The UKF is employed due to its ability in dealing with nonlinearity and stochastic nature of the EMI as well as the measurement noises. The proposed method is tested on a typical dc-dc buck converter in different operating conditions. The effectiveness of the proposed method is tested using some hardware-in-the-loop experiments using dSPACE1104 development platform.

Study on conducted EMI noise source modelling applied in electromagnetic compatibility analysis based on GA in cooperation with LM

In this study, a new method employing scattering parameters (SPs) method, genetic algorithm (GA) and Levenberg–Marquardt algorithm (LM) is proposed for modelling conducted electromagnetic interference (EMI) noise source impedance. On the basis of the impedance information extracted by traditional SP method, GA is adopted to optimise the impedance information by taking advantage of the fast convergence speed. The obtained values of the RCL parameter are used as a set of initial values. Then, by using the advantage of the high precision of the LM, the initial values obtained by the GA are iteratively calculated. Better results can be obtained by using this combination method. This method improves the processing accuracy while ensuring the processing speed and contributes to the design of conduction EMI filter.

Superhigh Electromagnetic Interference Shielding of Ultrathin Aligned Pristine Graphene Nanosheets Film.

Ultrathin, lightweight, high-strength, and thermally conductive electromagnetic interference (EMI) shielding materials with high shielding effectiveness (SE) are highly desired for next-generation portable and wearable electronics. Pristine graphene (PG) has a great potential to meet all the above requirements, but the poor processability of PG nanosheets hinders its applications. Here, efficient synthesis of highly aligned laminated PG films and nacre-like PG/polymer composites with a superhigh PG loading up to 90 wt% by a scanning centrifugal casting method is reported. Due to the PG-nanosheets-alignment-induced high electrical conductivity and multiple internal reflections, such films show superhigh EMI SE comparable to the reported best synthetic material, MXene films, at an ultralow thickness. An EMI SE of 93 dB is obtained for the PG film at a thickness of ≈100 µm, and 63 dB is achieved for the PG/polyimide composite film at a thickness of ≈60 µm. Furthermore, such PG-nanosheets-based films show much higher mechanical strength (up to 145 MPa) and thermal conductivity (up to 190 W m-1 K-1 ) than those of their MXene counterparts. These excellent comprehensive properties, along with ease of mass production, pave the way for practical applications of PG nanosheets in EMI shielding.

Thermally Conducting Polymer Composites with EMI Shielding: A review

Polymer composites have been a material of choice for lightweight and durable applications in sectors ranging from automobile, packaging, structural components, and electronics to energy harvesting. Their versatility and ability to be tailored to application requirements have made them prospective alternatives for metal enclosures used in communication systems, power electronics, electric motors, and generators. The easy processing and high strength-to-weight ratio provide advantages over traditional materials that involve time- and-labor intensive processes. However, high thermal conductivity (TC) and electromagnetic interference (EMI) shielding are factors limiting their penetration into niche markets, and thus the development of alternatives with high TC and EMI shielding efficiency is critical. Thermally conductive polymer composites and EMI shielding effectiveness (SE) is a current issue in different applications including polymers providing light weight, corrosion resistance, and ease of processing as compared with metal. This paper focuses on improvements in the TC and shielding effectiveness of polymers by incorporating various fillers including carbon-based, mineral-based, and hybrid fillers. The paper reviews the current research worldwide regarding the enhancement of the TC and shielding effectiveness of polymer composites.

Экспериментальное исследование для определения параметров импульсных кондуктивных электромагнитных помех в бортовой сети автомобиля КАМАЗ 5350

The widespread introduction of high-tech electronic products designed to work on military vehicles establishes the need to strictly meet the requirements for their electromagnetic compatibility for conductive interference in on-board networks. The article analyzes the sources of electromagnetic interference in the vehicle’s onboard network. The paper presents the results of experimental studies to determine the parameters of pulsed conductive electromagnetic interference in the on-Board network of the KAMAZ 5350 car and determine their compliance with the requirements for electromagnetic compatibility

A Simulation-Based Multifunctional Differential Mode and Common Mode Filter Design Method for Universal Converters

Existing filter design methods for grid-tied power converters either focus on grid current harmonic suppression or electromagnetic interference (EMI) noise attenuation. This article proposes a simulation-based, multifunctional filter design method, which can simultaneously handle multiple objectives, including minimizing grid current total harmonic distortion (THD), conductive EMI noise, ground leakage current, touch current, filter weight, and so on. By modeling equivalent filter circuit and simulating in the Powersim (PSIM) software, the approach avoids traditional complicated circuit analysis and mathematical computation. In addition, unlike most existing filter design approaches that only focus on one specific application or converter topology, this filter design method is a generalized approach and can also be used for universal converters that have variable applications. To demonstrate this feature, the filter design method is applied to a recently proposed series-capacitive-link universal converter. Experimental results verify the effectiveness of the proposed method.

Simulation and Analysis of Conductive Electromagnetic Interference in Near-Field Magnetic Coupling

Inductors, common-mode inductors, transformers and other magnetic components are important components of power converters. Their layout and wiring may affect the ability to suppress EMI noise. As a result of miniaturization and higher power density, the composition of power converter becomes more and more compact, which leads to the near-field coupling effect between components. In our study, the mechanism of near-field magnetic coupling between magnetic elements is analyzed, and the accuracy of the parameters of near-field magnetic coupling is further verified by experiments.

Evaluation Method of Flyback Converter Behaviors on Common-Mode Noise

Common-mode (CM) conduction electromagnetic interference (EMI) is a challenge for switched-mode power supply (SMPS) designers. A flyback converter is a traditional topology used in low-power isolated applications. The size and cost of EMI filters are important considerations for higher power density and lower cost of SMPS design. In most cases, the CM current is generated by voltage pulsation (dv/dt) assigned on the primary winding and the secondary winding. The CM current conduction paths can be mainly categorized into two categories. One is the interwinding parasitic capacitance of the transformer, and the other is the parasitic capacitance between the semiconductor switches and the protective ground. This paper proposed an evaluation method to measure the equivalent CM noise capacitance of the two main CM current conduction paths, respectively. Then, this paper proposed a CM noise cancellation scheme based on the transformer winding design combining the measurement technique and the FEM simulation tool. Planar transformers with PCB windings also have advantages in low profile, good heat dissipation, and good stray parameter consistency. Based on these considerations, an 18-W adapter is designed and tested to verify the effectiveness of the proposed evaluation method and the design scheme.

Frequency-Domain Optimization of Digital Switching Noise Based on Clock Scheduling

The simultaneous switching activity in digital circuits challenges the design of mixed-signal SoCs. Rather than focusing on time-domain noise voltage minimization, this work optimizes switching noise in the frequency domain. A two-tier solution based on the on-chip clock scheduling is proposed. First, to cope with the switching noise at the fundamental clock frequency, which usually dominates in terms of noise power, a two-phase clocking scheme is employed for system timing. Second, on-chip clock latencies are manipulated to target harmonic peaks in specific frequency bands for the spectral noise optimization. An automated design flow, which allows for noise optimization in user-defined application-specific frequency bands, is developed. The effectiveness of our design solution is validated by measurements of substrate noise and conductive EMI (electromagnetic interference) noise on a test chip, which consists of four wireless sensor node baseband processors each addressing a distinct clock-tree-synthesis strategy. Compared to the reference synchronous design, the proposed clock scheduling solution substantially reduces noise in the target GSM-850 band, i.e., by 11.1 dB on the substrate noise and 12.9 dB on the EMI noise, along with dramatic noise peak drops measured at the 50-MHz clock frequency.

Highly Effective Electromagnetic Interference Shielding Materials based on Silver Nanowire/Cellulose Papers.

We fabricated silver nanowire (AgNW)-coated cellulose papers with a hierarchical structure by an efficient and facile dip-coating process, and investigated their microstructures, electrical conductivity and electromagnetic interference (EMI) shielding effectiveness. SEM images confirm that AgNWs are coated dominantly on the paper surfaces, although they exist partially in the inner parts of the cellulose papers, which demonstrates that the AgNW density gradually decreases in thickness direction of the AgNW/cellulose papers. This result is supported by the anisotropic apparent electrical conductivity of the AgNW/cellulose papers depending on in-plane or thickness direction. Even for a AgNW/cellulose paper obtained by a single dip-coating cycle, the apparent electrical conductivity in the in-plane direction of 0.34 S/cm is achieved, which is far higher than the neat cellulose paper with ∼10(-11) S/cm. In addition, the apparent electrical conductivity of the papers in the in-plane direction increases significantly from 0.34 to 67.51 S/cm with increasing the number of dip-coating cycle. Moreover, although the AgNW/cellulose paper with 67.51 S/cm possesses 0.53 vol % AgNW only, it exhibits high EMI shielding performance of ∼48.6 dB at 1 GHz. This indicates that the cellulose paper structure is highly effective to form a conductive AgNW network. Overall, it can be concluded that the AgNW/cellulose papers with high flexibility and low density can be used as electrically conductive components and EMI shielding elements in advanced application areas.

Design and Comparison of Controller for the Reduction of Conducted Electromagnetic Interference in an Inverter

This paper presents the design of a controller for the measurement and reduction of conducted Electro Magnetic Interference (EMI) caused in the power electronic circuits. The conducted EMI is also separating the Common Mode (CM) and Differential Mode (DM) simultaneously using Line Impedance Stabilization Network (LISN). EMI is mitigated by the fuzzy controller. By comparing common mode voltage with the standard reference value, the generated error can be minimized by using fuzzy controller. Fuzzy controller is varying the PWM signal of the power electronic switching devices for reducing the electromagnetic interference. In this paper, comparison of PI and fuzzy controller of the open loop and closed loop models are implemented using MATLABr and also simulation results of the PI controller and fuzzy controller analysis are presented in this paper. The fuzzy controller is provided to achieve the EMI level of the inverter within the standard limit.

Error analysis in conductive electromagnetic interference noise source impedance extraction: A simulation and experimental study

Error analysis in conductive electromagnetic interference noise source impedance extraction: A simulation and experimental study

Electromagnetic interference caused by electric load of more electric aircraft

As an increasing number of power electronic converters are used in the electrical system of more electric aircraft( MEA),electro-magnetic interference( EMI) problems are becoming more and more severe both within the electrical systems and between different systems. Based on the electrical load characteristics of MEA,electrical load was classified into rectification,chopping and inverter. The conduction EMI current of the three major electrical load during the stable operation and the load surge of electrical loads were studied by modeling and simulations. EMI characteristics caused by the inverter load obtained was verified by experiments. The research results show that the conducted EMI to the power line is concentrated in the switch frequency of the power electronic device and the multiple frequency or so; the step change of the high power electrical load after the Buck chopper circuit makes the conduction EMI characteristics change significantly,which reflected in the frequencies of local maximum of amplitude spectrum. The study results provide the guidance for the EMI identification and the filter design of an independent electrical system.