Filter Components Research Articles

Straightforward Modeling of Frequency Dispersive and Nonlinear Common Mode Chokes for Transient Simulations

The simulation and design process of electromagnetic compatibility (EMC) filters need accurate models for their used components. Common mode chokes, which are essential filter components, exhibit a complex behavior that is usually hard to model for the purpose of transient circuit simulation. This article gives an easy method of modeling such components as long as hysteretic effects can be neglected. The process presented produces an easy to setup and easy to use SPICE model. The incorporated effects are the frequency dependent impedance behavior as well as the nonlinear effect from saturation processes. Both effects are well separated in the model and require only data from the manufacturer, thereby circumventing data fitting methods and measurements on samples with their lead and shipping time efforts. The frequency dependent behavior is modeled via a discrete <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RL</i> -ladder model whereas the nonlinear effects are integrated via treating the saturation as a phase transition. The choke modeling technique was verified for a typical current pulse shape. The comparison between the measurement and the simulation model showed a good match, especially for the maximum amplitude of the current pulse shape, which is essential to determine saturation.

Investigation of common mode voltages of single stage boost inverter for five phase induction motor drive

In this manuscript, the single stage boost inverter is proposed to eliminate the common-mode voltage (CMV) and electromagnetic interference (EMI) in the motor drives. The proposed topology has the capability of eliminating the effects of intrinsic CMV without any additional filters, active or passive elements, and modified pulse width modulated (PWM) techniques. This topology is proposed with the rearrangement of filter components from ac side to mid place in such a way that the capacitor constantly clamped to the DC bus, and the inductor is placed at the mid-point of half-bridge module and supply to achieve the high gain. This arrangement is also eliminating the effect of switching natured common-mode voltage, which generally occurs in any conventional PWM inverter. Conventional PWM techniques can be implemented to this topology without any modification in the control strategy. The proposed topology is simulated in a MATLAB Simulink to verify the operation and CM reduction capabilities with the results of experimental prototype. In the manuscript, the proposed topology is compared with the traditional inverters and modulation schemes in terms of the CMV effect elimination to explain its effectiveness.

Structurally integrated 3D carbon tube grid-based high-performance filter capacitor.

Filter capacitors play a critical role in ensuring the quality and reliability of electrical and electronic equipment. Aluminum electrolytic capacitors are the most commonly used but are the largest filtering components, limiting device miniaturization. The high areal and volumetric capacitance of electric double-layer capacitors should make them ideal miniaturized filter capacitors, but they are hindered by their slow frequency responses. We report the development of interconnected and structurally integrated carbon tube grid-based electric double-layer capacitors with high areal capacitance and rapid frequency response. These capacitors exhibit excellent line filtering of 120-hertz voltage signal and volumetric advantages under low-voltage operations for digital circuits, portable electronics, and electrical appliances. These findings provide a sound technological basis for developing electric double-layer capacitors for miniaturizing filter and power devices.

Acoustic Modelling from Raw Source and Filter Components for Dysarthric Speech Recognition

Acoustic Modelling from Raw Source and Filter Components for Dysarthric Speech Recognition

A half-bridge distributed static compensator with a DC-link filter capacitor of a reduced size LCL filter

Distributed static compensators (DSTATCOMs), composed of power converters and passive filters, have been extensively utilized in distribution systems to improve their power quality. For the selection of passive filters, LCL filters with smaller sizes and lower costs are increasingly being adopted to replace the conventional L filters. However, the filter components of LCL filters are normally designed for the application of grid-connected inverters, and therefore, these passive components can be further optimized when applied to the DSTATCOM, where the grid-injected current is mainly capacitive. In this study, the novel LCL-filtered half-bridge DSTATCOM topology is proposed, where the conventional filter capacitor of the LCL filter is replaced by the DC-link capacitors with relatively larger capacitances. As a consequence, the grid-side inductance can be dramatically reduced from the order of millihenry to several microhenries. Furthermore, the current stress of semiconductor switches can be decreased. In addition, the power flow analysis and filter design procedure are presented in this study. It is revealed that a constant DC-link voltage can always be maintained, and the voltage variation across each capacitor can be well regulated with properly designed filters and controllers. Experiments were carried out on a down-scaled laboratory prototype, and simulation and experimental results are presented to verify the effectiveness of the proposed DSTATCOM topology.

Investigation of Electron Contamination on Flattened and Unflattened Varian Clinac iX 6X and 15X Photon Beam Based on Monte Carlo Simulation

The aim of this study was to characterize electron contamination of a flattened (FF) and an unflattened (FFF) Varian Clinac iX 6X and 15X photon beams using Monte Carlo (MC) simulation. EGSnrc MC technique was used to model the flattened and unflattened head and simulate dose distribution of 6X and 15X of FF and FFF photon beam in water phantom. The materials and geometrical data of FF linac were provided by Tan Tock Seng Hospital (TTSH) Singapore. The FFF linac was modeled by removing the flattening filter component in the FF linac. Phase space files were scored after flattening filter and in the phantom surface. The phsp files were analyzed to characterize the particles produced by the linac head using BEAMDP. The contaminants contribute around 1 % and 2 % in the phsp1 for flattened and unflattened beams, respectively. The photons are scattered in small-angle in the range of 0 – 4 o . The contaminant electron contributes up to one hundredth compared to the photons. The increase of field area affects the increase in contaminants and penumbra width due to the increasing number of particle scattered out of the field area. The unflattened beam affects the increase in the number of electron contamination and surface dose. The penumbra width of the flattened beams was smaller than the unflattened beams for the same field size and energy.

Formation of Orthogonal Components of Input Signals in Digital Measuring Protection Elements with Correction of Dynamic Errors

Digital measuring elements in microprocessor protections of electrical installations are implemented mainly with the use of orthogonal components of input signals. To form orthogonal components in microprocessor protections, digital Fourier filters are most widely used, the action of which is al-ways inertial in transient modes. As a result, a dynamic error appears, changing over time and completely disappearing when a steady-state regime occurs. The dynamic error consists of amplitude and phase errors, which can significantly affect the functioning of digital measuring elements and create conditions for their excessive triggering during external short circuits and deceleration of triggering during internal short circuits. Therefore, it is advisable to compensate for the dynamic error, for which it is proposed to determine the amplitude and phase of the fundamental harmonic signal by specially formed orthogonal components. The proposed method of forming orthogonal components of the signal with compensation of dynamic amplitude and phase errors is based on the use of orthogonal components of the digital Fourier filter, followed by the determination of their samples of the final orthogonal components that coincide with the orthogonal components of Fourier in steady-state mode and shifted in phase relative to the latter in transient mode. The amplitude and phase of the signal with minimal dynamic phase errors are calculated from the samples of the final orthogonal components in the digital measuring element. In the dynamic modeling environment of MATLAB-Simulink-SimPowerSystems, a digital model is implemented, which includes a power system, a three-phase group of current transformers, a load, a short-circuit block, as well as a model of a digital measuring element implemented on the basis of the final orthogonal components. The operation of the digital model was checked using two types of test effects, viz. a sinusoidal signal with a frequency of 50 Hz, and a signal close to the real secondary current of a short-circuit current transformer. As a result of the calculations, it was found that digital measuring elements made on the basis of the proposed methodology made it possible to reduce the relative dynamic amplitude and phase errors by three to four times, as compared with the Fourier measuring element taken as a reference.

A 5.3 GHz Al0.76Sc0.24N Two-Dimensional Resonant Rods Resonator With a kt2 of 23.9%

This work reports on the measured performance of an Aluminum Scandium Nitride (AlScN) Two-Dimensional Resonant Rods resonator (2DRR), fabricated by using a Sc-doping concentration of 24%, characterized by a low off-resonance impedance (~25 Ohm) and exhibiting a record electromechanical coupling coefficient (kt2) of 23.9% for AlScN resonators. In order to achieve such performance, we identified and relied on optimized deposition and etching processes for highly-doped AlScN films, aiming at achieving high crystalline quality, low density of abnormally oriented grains in the 2DRR's active region and sharp lateral sidewalls. Also, the 2DRR's unit-cell has been acoustically engineered to maximize the piezo-generated mechanical energy within each rod and to ensure a low transduction of spurious modes around resonance. Due to its unprecedented kt2, the reported 2DRR opens exciting scenarios towards the development of next generation monolithic integrated radio-frequency (RF) filtering components. In fact, we show that 5th-order 2DRR-based ladder filters with fractional bandwidths (BW) of ~11%, insertion-loss (I.L) values of ~2.5 dB and with >30 dB out-of-band rejections can now be envisioned, paving an unprecedented path towards the development of ultra-wide band (UWB) filters for next-generation Super-High-Frequency (SHF) radio front-ends.

Development of an Integrated Soft E-Nose for Food Quality Assessment

Food is one of the basic essential elements for human beings. Its quality is directly related to our physical, emotional, and social well-being. An electronic nose is a non-destructive instrument and is an effective solution for quick and easy determination of food quality. In this paper, an integrated soft E-nose methodology focusing on performance enhancement and complexity reduction is proposed and implemented for the effective classification of beef quality and prediction of microbial population in beef. The soft E-nose methodology is tested on 18 available datasets. Ours is a four-step approach that includes validated data collection, signal processing with a moving average filter and principal component analysis for feature reduction, efficient pattern recognition using machine learning and deep learning techniques like support vector machine, k-nearest neighbors, artificial neural network, extreme learning machine, and deep neural network for classification and regression, and an output stage for classification and prediction of the microbial population of beef. This methodology could provide accuracy greater than 98% using k-nearest neighbors, artificial neural network methods, and a correlation coefficient of greater than 0.98 using support vector machine and artificial neural network methods. The proposed methodology is validated using 10-fold cross-validation.

Speech recognition system based multi-level selective filter

In this paper, an updated source-filter based method is used for speech recognition of English speakers. The key goal of this paper is to discuss the influence of using dynamic and selective Filterbank on the efficiency of the system in terms of identifying the word being said. Dynamic structures of the bandpass filter bank are clearly able to adjust their principles in conjunction with the speech database used. In this paper, the proposed methods adopted the idea of re-select or adjusting the filter parameters values at each iteration, in accordance with the word being processed. In other words, the values of the filter components (center frequencies and bandwidths) will adjust until it gets the best set of the filter components. The genetic algorithm (GA) will be used to maintain the components of the filter and each new population of the GA represents a new set of channels for the filter bank. Results show that the efficiency of the recognition system would be improved with each new set of filter components generated by the genetic algorithm. Speech recognition, Source-filter, Filterbank, genetic algorithm, adjusted filter, Dynamic system

Çok Ölçekli Temel Bileşen Analizi ve Evrişimsel Sinir Ağları ile Elektrokardiyografi Sinyallerinden Miyokart Enfarktüsünün Tespiti

Myocardial Infarction is a vital disease that needs to be intervened in a very short time. The analysis of the patient's electrocardiography (ECG) data has an important place in the diagnosis. For this reason, computer aided decision support systems have been used in recent years in order to determine this disease more quickly and accurately. In this study, classification was made using convolutional neural network algorithms on the ECG signals obtained from 61 patients diagnosed with myocardial infarction and 52 healthy individuals. ECG signals are preprocessed with three different filters by applying finite impulse response (FIR) filter, infinite impulse response (IIR) filter and multiscale principal component analysis. According to the results obtained, classification success was achieved with 92.3% accuracy by using the preprocessed signals using multi-scale principal component analysis, and it was seen that more successful classification performance was obtained compared to the classification of the preprocessed signals with the help of FIR, IIR filter.

Magnetic molecules as local sensors of topological hysteresis of superconductors

Superconductors and magnetic materials, including molecules, are key ingredients for quantum computing and spintronics. However, only a little is known about how these materials interact in multilayer nanostructures like the hybrid architectures nowadays under development for such advanced applications. Here, we show that a single layer of magnetic molecules, Terbium(III) bis-phthalocyaninato (TbPc2) complexes, deposited under controlled UHV conditions on a superconducting Pb(111) surface is sensitive to the topology of the intermediate state of the superconductor, namely to the presence and evolution of superconducting and normal domains due to screening and penetration of an external magnetic field. The topological hysteresis of the superconducting substrate imprints a local evolution of the magnetisation of the TbPc2 molecules in the monolayer. Element and surface selective detection is achieved by recording the X-ray magnetic circular dichroism of the Tb atoms. This study reveals the impressive potential of magnetic molecules for sensing local magnetic field variations in molecular/superconductor hybrid devices, including spin resonators or spin injecting and spin filtering components for spintronics applications.

More electric aircraft challenges: A study on 270 V/90 V interleaved bidirectional DC–DC converter

The concept of more electric aircraft (MEA) has gained increased importance in the aviation industry to make the aircraft energy efficient and reduce carbon footprints. MEA facilitates transition towards clean energy and accomplishing the United Nations’ net-zero emission goal by 2050. An efficient and reliable dc–dc converter is an indispensable part of the MEA that interfaces 270VDC and 28VDC bus bars in aircraft applications. Dual Active Bridge is a well-known and promising topology for this application; however, the problem of current and voltage ripples deteriorates the life of the battery and filtering components. In addition, the mentioned voltage levels demand high voltage gain, which makes design challenging. To reduce the voltage gain requirement along with ripple minimization, a two-stage bidirectional converter is proposed by combing a three-phase interleaved buck-boost converter with Dual Active Bridge. The three-phase interleaved bidirectional converter is modelled and analysed using the state-space averaging method, and a controller is established. Simulation results demonstrate the efficacy of the design. The research carried out in this paper can serve as a reference and offer future research directions using the proposed idea, which might assist other researchers in developing an efficient design, eventually facilitating the MEA and carbon footprint reduction.

Dual-Band Design Techniques for Microwave Passive Circuits: A Review and Applications

The introduction of new technology in the wireless communication industry increases the number of frequency bands in the communication environment. Therefore, a communication system capable of functioning over several frequency bands, known as a <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">multiband communication system</i> , is required. In addition, multiband communication systems support technology upgrades by smoothly bridging the migration from the existing technology to a newer technology. A multiband communication system can be developed with the help of two approaches. The first approach is a multiband communication system that contains multiple microwave circuits, with each circuit optimized for a single band; for example, a dual-band communication system has two low-pass filters and two power amplifiers. But this approach increases not only the size but also the cost of the system. In the second approach, rather than using a separate power amplifier and filter for each frequency band, a single power amplifier, filter, and other components are used that can support more than one frequency band. These circuits are known as <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">multiband microwave circuits</i> . Multiband circuits not only minimize size but also reduce the cost of designing the multiband communication system.

Reconfigurable high-Q terahertz filtering of VO2-based metamaterials using optical tunneling

Up to date, reconfigurable terahertz (THz) band-pass filters based on the design of metamaterials with vanadium dioxide (VO2) have been investigated extensively. However, VO2-based THz metamaterials with high-quality tunable narrowband transmission and good stop-band rejection have yet to be reported, which are essential for THz wave filtering components or systems. Here, we propose a reconfigurable filter in combination with a dielectric metastructure and a VO2 thin film. Utilizing the optical tunneling effects of a cavity layer, the filter has a high band-pass transmission up to 98% at 0.246 THz with a narrow bandwidth of 0.0009 THz, an ultra-high Q-factor of 273, and two broad nearly-suppressed sidebands. The transmission intensity can be modulated by the phase transition of VO2, and the modulation depth is as high as 96.4%. By efficiently tuning the cavity layer thickness, the filter can be designed for a series of transmission wavelengths and further accomplish the switch between the narrow band-pass filtering and wideband reflection. Moreover, the manipulation of the incident angle and polarization can be adopted as an additional degree to achieve a similar switching function. Our study implies a potential for developing various THz applications, where reconfigurable high-Q THz filtering is required.

Conducted emission study in space vector modulated voltage source inverter

&lt;p&gt;To comply with electromagnetic interference (EMI) standards, the electromagnetic noise generated by power electronic converters must be analyzed and suppressed since the switching frequency of the converter affects EMI noise. Conducted emission occurs in drive systems due to inverter parasitic capacitances and rapidly switching inverter output voltages. The EMI noise produced space vector pulse width modulation (SVPWM) inverter is calculated using MATLAB/Simulink simulation data. The unwanted common mode and differential mode signals produced by the inverter are captured using a spectrum analyzer and examined using short time Fourier transform (STFT). To mitigate the effect of EMI in the circuit and to comply with the standards filters are developed. The passive filter components are defined by the EMI standards attenuation requirements. The MATLAB simulation findings are confirmed and verified by hardware implementation.&lt;/p&gt;

Recent advances in various chromatographic techniques used for analysis of drugs in pharmaceutical products: A review

Chromatography is a vital biophysical method that allows for the separation, identification, and filtering of components in order to conduct quantitative research. High efficiency, quicker separation speed, high flow rate, increased detection sensitivity, and cost savings are all advantages of novel chromatography methods. The goal of using chromatography, which is a technique for quantitative investigation separated from its partition, is to accomplish a satisfactory separation in a reasonable amount of time. The objective of chromatography is to analyze a sample qualitatively and quantitatively and its primary function is to clean and separate at least one component of the sample. It examines new and emerging chromatography techniques, as well as main standards. Phospholipids can be determined qualitatively and quantitatively using a variety of analytical procedures. Current new chromatographic methods are presented in this review.

Online Deformation Measurement of Laser Repair Substrate Based on Orthogonal Sampling Moiré

As an important branch of metal additive manufacturing, laser repair has broad application potential in the aerospace, automobile and ship building industries. In the process of laser repair, metal powder is introduced into the laser action area and heated to a molten state to form a molten pool, which moves on the component surface according to the preset scanning path. Additionally, the temperature of the repaired component changes dynamically with the movement of the molten pool, leading to the time-evolution of stress and deformation. Therefore, online deformation measurement for the repair process is essential for understanding the evolution mechanism of stress and deformation in laser repair. However, extreme environments such as ultra-high temperature, strong laser radiation and metal powder splashing exist during the laser repair, which bring great challenges for dynamic optical measurement. In this paper, an online deformation measurement system based on orthogonal sampling moiré for laser repair environment is developed, which is applied to measure the deformation field of the metal substrate during laser repair. In the measurement, laser repair is performed on a cantilever beam substrate and orthogonal grating is prepared on the side surface of the cantilever beam. The real-time grating images are recorded by an optical imaging system, in which a group of filter components are used to obtain optical images with high signal-to-noise ratio. Finally, the deformation field of the substrate during laser repair is calculated with the orthogonal sampling moiré method. The results show that the scanning path in the repair process has a significant influence on the distribution of residual deformation, which offers reference for optimizing parameters of laser repair.

Abstract No. 162 Medium and long-term outcomes of single session inferior vena cava filter removal, recanalization and endovenous reconstruction for filter-related chronic iliocaval thrombosis

Endovascular management of inferior vena cava filter (IVCF)-related chronic iliocaval thrombosis historically consisted of stent placement across an obstructed IVCF; however, there are data that suggest that this may result in compromised patency and higher rates of reintervention. Stent placement across an obstructed IVCF may result in incomplete stent expansion. Furthermore, IVCF displacement can result in adverse events (AE) including pericaval filter component perforation. We present medium and long-term outcomes following the single-session endovenous reconstruction of IVCF-related chronic iliocaval thrombosis with simultaneous IVCF retrieval.

Dual space vector PWM technique for a three-phase to five-phase quasi Z-source direct matrix converter

ABSTRACT This article proposes a dual space vector PWM control technique for a three-phase to five-phase quasi Z-source direct matrix converter (QZSDMC). The proposed circuit consists of a quasi-impedance source network along with a five-phase traditional matrix converter. With the observation of bidirectional operating capability and the utilization of shoot-through duty ratio, the proposed converter can ensure both buck and boost operations. This converter overcomes the voltage transfer ratio restriction and poor voltage regulation of the traditional matrix converter. Also, this converter ensures continuous input current with an absence of input LC filter components. The proposed direct AC to AC power converter gives an alternate solution to the multiphase drive system instead of the traditional voltage source inverter. The developed dual space vector PWM control technique for three-phase to five-phase voltage conversion is derived from the basic space vector PWM approach. The proposed dual space vector PWM technique utilizes 90 active states and 3 zero vector states among 243 switching states. The QZSDMC has been analysed with a dual space vector PWM approach along with the distribution of shoot-through state in the zero vector. The proposed topology along with the control strategy has been simulated using MATLAB/Simulink environment.