High Inductance Values Research Articles

A miniaturized dual band pass frequency selective surface insensitive to oblique angles and polarizations of wave

Abstract A Dualband Pass Frequency Selective Structure (DPSFSS) with miniaturized elements is proposed in this article. The miniaturized elements induce high inductance and capacitance values. The meandered line concept is used which extensively increases inductance of the dipole element. Very large capacitance is obtained between two meandered elements which have wide common area perpendicular to electric field for wave propagating in Z-direction. Two pass band poles and two zeros are obtained by perpendicular arrangement of meandered patterns on two sides of the substrate. Orthogonal arrangement of patterns ensure polarization symmetry (polarization insensitive) for Transverse Electric (TE) and Transverse Magnetic (TM) modes of exciting wave. Two pass band pole frequencies are positioned at 1.84 GHz and 4.53 GHz with low Insertion Losses (IL) of 0.67 dB and 1 dB, respectively. The lower and higher frequency bands have factional bandwidths of 41 % and 46 %, respectively. The transmission nulls occupy 2.8 GHz and 6.58 GHz frequencies. The structure is miniaturized to 0.032λ 0 × 0.032λ 0 dimensions with respect to lowest resonance residing at 1.83 GHz. The low IL at both pass bands is realized despite of using a lossy FR-4 material that can be improved to less than 0.5 dB at both the bands using less lossy materials such as F4BME or RO4003C. The proposed DPSFSS design is elaborated using Equivalent Circuit Model (ECM) and Surface Current Distribution (SCD). Measurements are performed on fabricated DPSFSS prototype and it is observed that the measured results coincide well with the simulated response. Angle stability of the DPSFSS is excellent and no unwanted resonances are observed at oblique angles upto 80° for dual polarizations of wave.

Modeling and Simulation of a Planar Permanent Magnet On-Chip Power Inductor

The on-chip integration of a power inductor together with other power converter components of small sizes and high-saturation currents, while maintaining a desired or high inductance value, is here pursued. The use of soft magnetic cores increases inductance density but results in a reduced saturation current. This article presents a 3D physical model and a magnetic circuit model for an integrated on-chip power inductor (OPI) to double the saturation current using permanent magnet (PM) material. A ~50 nH, 7.5 A spiral permanent magnet on-chip power inductor (PMOI) is here designed, and a 3D physical model is then developed and simulated using the ANSYS®/Maxwell® software package (version 2017.1). The 3D physical model simulation results agree with the presented magnetic circuit model, and show that in the example PMOI design, the addition of the PM increases the saturation current of the OPI from 4 A to 7.5 A, while the size and inductance value remain unchanged.

Influence of the Cast Iron Frame on the Distribution of the Magnetic Field in the Stator Yoke and Additional Power Losses in the Induction Motor

Induction motors are a significant consumer of electricity. Therefore, their energy efficiency level plays a vital role in the world’s energy balance. The world’s markets strive to produce motors of efficiency class IE3 or IE4 while maximizing the use of wire and magnetic materials. However, high induction values in the motor core can also lead to significant losses in construction materials, especially in the magnetic motor housing. This article aimed to show how it is possible to determine the distribution of the magnetic field and additional losses in the yoke and the cast-iron motor frame using field-circuit methods to model the motor and to refine the analytical method for calculating these losses at the motor design stage.

Skin Effect and Losses in Soft Magnetic Sheets: From Low Inductions to Magnetic Saturation

High frequencies are ubiquitous in present-day power applications: most electrical equipment, like rotating machines, are supplied by Pulse Width Modulation (PWM) switching inverters, often working at tens or hundreds of kilohertz. PWM is responsible of minor cycles along the major hysteresis loop of the magnetic core, lasting a few microseconds. Such minor loops can cause deep skin effect, even if the thinnest today available laminations (0.1 - 0.2 mm thick sheets) are used. Common mode currents in the megahertz range, flowing from the electrical machine windings to the machine chassis through capacitive effects, can engender strong electromagnetic disturbances and bearing damages. A correct prediction of high frequency phenomena is necessary, for example, for the accurate calculation of common mode filters, requiring a magnetic model of the laminated cores suited to high frequencies and low induction values and the ensuing dramatic skin effect. For power conversion applications, such as embedded planar transformers, the mandatory reduction of volume and cross-sectional area of the core, often made of high-permeability grain-oriented (HGO) sheets, imposes the increase of the conversion frequency from a few hundred hertz to several kilohertz and high peak induction values. The skin effect in this case is affected by the non-linear saturable magnetic response of the material and its treatment requires non-trivial experimental methods and modeling approaches. In this work, we discuss physically based modeling of magnetization process and energy loss in magnetic sheets at high frequencies. We focus first on the low induction regimes occurring in thin non-oriented (NO) Fe-Si laminations. We consider then the case of high inductions, as encountered in power conversion devices using NO, HGO, and Fe-Co alloys, where non-linear models, possibly validated by magneto-optical observations of the domain wall dynamics, are developed and implemented.

The effect of magnetic and electric fields on the processes of food freezing

The article summarizes the results of studies based on scientific publications on the effect of magnetic fields (MF) and electric fields (EF) on the kinetics of freezing processes applied onto biological tissue and on their properties. The processes of freezing food media on installations equipped with the Cells Alive System (CAS) magnetic system manufactured by ABI Co., Ltd., Japan are considered in this article. It is shown that the majority of researchers did not confirm the benefits claimed by the CAS system developers in comparison with the processes of fast freezing in the chambers without the magnetic field. In the case of using the alternating magnetic fields (AMF) with high field induction values, the effect is more pronounced. The application of strong static or alternating EF contributes to the creation of a fine-grained structure of ice, reduces the freezing duration and decreases mass loss during the food thawing.

Comparative Study of Different Topologies of Monolithic On-Chip Planar Transformer for Optical VCSEL Driver

This article presents a comparative study of different topologies of monolithic on-chip planar transformer, operating at high frequencies and suitable for optical VCSEL driver. The vertical cavity surface emitting laser (VCSEL) driver is presented for optical transceiver systems. At the VCSEL driver output stage, the on-chip transformer is used to compensate for large bandwidth and deliver adequate gain. On-chip transformer equivalent circuit model has been proposed and used for simulation and measurement. The eye pattern results show that the VCSEL driver with an on-chip transformer presents good performance. Different topologies of the on-chip transformer are compared and 0,5 µm CMOS technology measurements are considered in the frequency range from 1 GHz to 10 GHz. Square, hexagonal, octagonal, and circular topologies of on-chip transformer have been compared. The circular topology presents a good performance and high-quality factor. The square shape provides a high inductance value and low quality compared to the other topologies.

Modeling of TSV-based 3-D Heterogeneous Solenoid Inductor with High Inductance Value

Modeling of TSV-based 3-D Heterogeneous Solenoid Inductor with High Inductance Value

A Comparative Study on Parasitic Capacitance in Inductors With Series or Parallel Windings

In high-power medium-voltage applications, inductors usually have multiple windings on a single core, due to the high inductance value and high current stress. The multiple coils are electronically connected in either series or parallel, with considerations of windings loss and cost. However, the differences in parasitic capacitance of inductors using parallel and series connections are not discussed. Therefore, this article reveals that in comparison to parallel connections for windings, utilizing series connection for winding can significantly reduce the parasitic capacitance in multiwindings inductors without sacrificing the power density and adding manufacturing complexities. Physics-based models of parasitic capacitance in inductors with round-cable and copper-foil windings are developed for theoretical analysis. According to the theoretical analysis, the equivalent capacitance contributed by the stored electric field energy between two layers can be halved at least. The theoretical analysis is also verified by FEM simulations. Six prototyped inductors are experimentally compared to validate the theory.

An energy efficient modified passive power filter for power quality enhancement in electric drives

In most industrial applications, AC drives are used. These drives require power electronic modules to convert AC to DC and also DC to AC. The power modules used for power conversion consist of power semiconductor switches. There is distortion in the voltage and current obtained from the power modules due to non-linear behaviors of semiconductor switches. To reduce the distortion in the input current, inductors are used along with the line impedance. A high value of inductance is required to maintain the percentage of THD within limits set by the latest standards. Along with the increased size and cost, it also reduces the power factor and output DC voltage at higher loads. The use of a passive power filter (PPF) is the conventional method followed for the reduction of percentage THD and promotion of the power factor. PPFs comprise passive elements such as the resistor, inductor, and capacitor. These passive elements are connected at the point of common coupling (PCC) in shunt to compensate for the harmonics present in the input current. In this study, a modified multi-tuned passive filter is considered to reduce the source current harmonics. A bridge rectifier with resistive load, three-phase induction motor drive, and linear resistive–inductive load is connected at the point of common coupling to analyze the harmonics present in the source current, and also unbalanced created in one phase. To achieve proper selection of the resistance value for the passive filter, the class topper optimization technique is used. To validate the simulation results obtained for the multi-tuned passive filter, the hardware is implemented with a three-phase AC induction motor drive load, in which the speed of the motor is controlled with voltage by a frequency control algorithm using an FPGA controller; The 50% THD is reduced by using the fifth-order filter alone, 75% by combining the fifth- and seventh-order filters, 85% by combining the 5th-, 7th-, 11th-, 13th-, and higher-order filters, and 90% for varying loads. For single-phase AC induction motor load, THD % is reduced to 4%, and for three-phase AC induction motor drive, THD % is reduced to 10% with the same value of the filter.

SINTESIS DAN KARAKTERISASI NANOPARTIKEL OKSIDA BESI MENGGUNAKAN METODE BALL MILLING DAN KOPRESIPITASI

This Research has carried out on natural sand originating from the Rokan river, Riau Province by converting it into magnetic iron oxide nanoparticles to determine changes in magnetic properties and particle size. Natural sand samples of the Rokan river were separated between magnetic and non-magnetic particles using an iron sand separator (ISS). ISS products are further synthesized using ball milling and coprecipitation methods. 70-hour ball milling products, coprecipitation without ball milling and coprecipitation with 70-hour ball milling are then given NdFeB (neodymium iron boron) magnets to clean impurities containing non-magnetic elements. The results of this study showed that the highest magnetic acceptability value was obtained in coprecipitation products with ball milling, which was 12.9 × 10 -2 . This is because coprecipitation products have an abundant content of chemicals in the form of magnetic elements. Based on the results of chemical composition testing using X-ray flourescence (XRF) it was found that in coprecipitation products with ball milling there was 64.504% iron (Fe) content, while 70-hour ball milling products and coprecipitation without ball milling the percentage of Fe protection was 15.023% and 54.152%, respectively. Based on the results of the identification of the chemical composition in the sample, coprecipitation products with 70-hour ball milling have high magnetic induction values and magnetic suseptibility caused by the magnetic content in products such as Fe which are very high and non-magnetic content is very low such as Si compared to 70-hour ball milling products and coprecipitation products without ball milling.

Sensitivity Analysis and Small-Signal Stability of Grid Following Converters

This article presents a small-signal study, based on a sensitivity analysis, of a voltage source converter (VSC) operating as a grid-following device. This type of operation is standard for integrating distributed energy resources directly into a primary grid without considering the control over specific variables (e.g., voltage and frequency), thus maximizing the amount of injected active power. The present study adopted the classical vector-oriented control based on the linearization method of the averaged model; hence, this analysis is limited to linear controls. The main objective of this study is to evaluate how each controller parameter influences the system’s stability. To conduct the sensitivity analysis, an averaged model in the dq reference frame of the VSC was employed to describe the system dynamics in the equivalent state-space model. Afterward, the stability was analyzed through a sensitivity analysis of the eigenvalues of the corresponding state matrix. The numerical results demonstrate that the main problems for the stability of VSCs operating as grid-following converters are threefold: a high value of the filter inductance, a non-ideal impedance that appears depending on the connection point, and poor coordination of the parameters of the Kp controllers. These results are compared to a simple bifurcation analysis of the state matrix, which consists of a diagram that describes the variation in eigenvalues when a parameter changes, thus proving their validity.

Self-Driven Reverse Thermal Engines Under Monotonous and Oscillatory Optimal Operation

Abstract The complex time-dependent heat and electromagnetic energy transfer in a new type of reverse thermal engine is analyzed. The reverse thermal engine consists of a cold body, a Peltier element and an electric circuit containing an inductor with controllable inductance. This system allows cooling a body below the ambient temperature. The inductor acts as an accumulator of magnetic energy, receiving electrical work from the Peltier element during some time intervals and supplying the Peltier element with electrical work during other time intervals. The system is named self-driven reverse thermal engine since one of its subsystems (the inductor) receives and releases work. The new type of engine has features which make it different from classical reverse thermal engines: it cannot operate in steady state and it operates for a finite time interval. Instead of usual indicators of performance such as the coefficient of performance, other performance indicators should be used, such as the minimum cooled body temperature and the interval of time needed to reach a given cooled body temperature. Significant cooling effects do not necessarily need high inductance values. The operation of the new engine has been optimized by using direct optimal control procedures. The open-source program package BOCOP has been used to transform the optimal control problem into a non-linear dynamic problem. The minimum temperature reached by the cooled body depends on its mass. There exists, however, a global minimum temperature, for a specified optimum mass of the cooled body. The minimum temperature decreases by increasing the value of the Seebeck coefficient and by decreasing the thermal conductance. Thermal damped oscillations may arise under special circumstances. This implies a very small difference between the initial temperatures of the cold and cooled bodies and a specific range of variation for the conductance of the Peltier element.

Evaluation of Double Loop IC Module for Inductive Coupled Fed RFID Tag Wire Embedded Antenna

This paper presents an evaluation on double loop integrated circuit module for inductive couple fed RFID Tag. The inductive couple feed gives advantage especially for flexible wire embedded antenna in controlling the manufacturing varians as the chip is not directly connected to the antenna. Thus electrostatic discharged effect and manufacturing errors can be minimized. An inductor loop is directly connected to the RFID chip before it is placed to indirectly coupled the energy from a meandered dipole antenna. The coupled energy should be enough to turn on the chip to communicate with the reader. The inductive coupled energy is achieved by manipulating the near field magnetic field between the antenna body and the inductor loop. To evaluate the performance, the antenna and the inductive feeding loop is designed to operate at RFID UHF band (860 MHz – 960 MHz) and simulated using CST software. The antenna body impedance is evaluated to match the impedance of the chip and the loop. It is confirmed that the double loop inductor has higher inductance values and thus should be counted in conjugate impedance between the antenna body and the chip module. The tag with overall dimension of 60 mm x 16 mm can be read at distance at least 9 meters through out the band.

High-voltage synthetic inductor for vibration damping in resonant piezoelectric shunt

Resonant piezoelectric shunts are a well-established way to reduce vibrations of mechanical systems suffering from resonant condition. The vibration energy is transferred to the electrical domain through the bonded piezoelectric material where it is dissipated in the shunt. Typically, electrical and mechanical resonance frequencies are several orders apart. As such, finding a suitable high inductance component for the resonant shunt is not feasible. Therefore, these high inductance values are mimicked through synthetic impedances, consisting of operational amplifiers and passive components. A downside of these synthetic impedances is that standard operational amplifiers can only handle up to 30 V peak to peak and the state-of-the-art amplifiers up to 100 Vpp. However, as mechanical structures tend to become lighter and more flexible, the order induced voltages over the piezoelectric material electrode voltages increase above these limitations. In this research, a high-voltage synthetic inductor is proposed and built by combining the bridge amplifier configuration and the output voltage boost configuration around a single operational amplifier gyrator circuit, effectively quadrupling the range of the synthetic inductor to 400 Vpp. The impedance of the circuit over a frequency range is numerically and experimentally investigated. The synthetic inductor is then connected to a piezoelectric material bonded to a cantilever beam. Numerical and experimental investigation confirms the high-voltage operation of the implemented circuit and its suitability as a vibration damping circuit.

High-Sensitivity, Quantified, Linear and Mediator-Free Resonator-Based Microwave Biosensor for Glucose Detection.

This article presents a high-sensitivity, quantified, linear, and mediator-free resonator-based microwave biosensor for glucose sensing application. The proposed biosensor comprises an air-bridge-type asymmetrical differential inductor (L) and a center-loaded circular finger-based inter-digital capacitor (C) fabricated on Gallium Arsenide (GaAs) substrate using advanced micro-fabrication technology. The intertwined asymmetrical differential inductor is used to achieve a high inductance value with a suitable Q-factor, and the centralized inter-digital capacitor is introduced to generate an intensified electric field. The designed microwave sensor is optimized to operate at a low resonating frequency that increases the electric field penetration depth and interaction area in the glucose sample. The microwave biosensor is tested with different glucose concentrations (0.3–5 mg/ml), under different ambient temperatures (10–50 °C). The involvement of advanced micro-fabrication technology effectively miniaturized the microwave biosensor (0.006λ0 × 0.005λ0) and enhanced its filling factor. The proposed microwave biosensor demonstrates a high sensitivity of 117.5 MHz/mgmL-1 with a linear response (r2 = 0.9987), good amplitude variation of 0.49 dB/mgmL-1 with a linear response (r2 = 0.9954), and maximum reproducibility of 0.78% at 2 mg/mL. Additionally, mathematical modelling was performed to estimate the dielectric value of the frequency-dependent glucose sample. The measured and analyzed results indicate that the proposed biosensor is suitable for real-time blood glucose detection measurements.

A Compact Magnetically Dispersive Surface for Low-Frequency Wireless Power Transfer Applications

We present a compact, magnetically dispersive engineered surface for resonant inductive wireless power transfer (WPT) that significantly enhances the performance of an inductive link, increasing the efficiency and/or working distance. The proposed metasurface measures 6 cm $\times 6$ cm $\times0.1$ cm, achieving a greatly reduced thickness over a 3-D metamaterial, especially relative to the long wavelength at the chosen operating frequency of 5.77 MHz, which is in the range of typical wireless biomedical implants. Such feature is obtained by virtue of an extremely compact connected double-spiral unit cell, which provides high inductance values despite the small size. We prove through numerical simulations that the proposed metasurface considerably lowers the electric field level with respect to traditional two- or three-coil WPT systems, while maintaining the same magnetic field level at the receiver. In addition, we conducted efficiency measurements on a fabricated prototype, confirming the performance of our design. The excellent efficiency enhancement, combined with the resulting low electric field, makes the proposed metasurface an attractive solution for a number of WPT applications, especially where the exposure in terms of specific absorption rate (SAR) is one of the major concerns, such as in biomedical implants and rechargeable devices.

An Innovative Near-Field Communication Security Based on the Chaos Generated by Memristive Circuits Adopted as Symmetrical Key

The new technology solutions are playing an important role in the hardware security. One of the latest techniques is the use of the Memristor as an encryption element. In this paper, it has been introduced a two-column array inductor for Memristor-Based Wireless Power Transfer (M-WPT) systems. The traditional WPT circuits are based on switches, which do require a control circuit for timing and have low data encryption factor. By adopting the memristive Chua`s circuit with the chaotic behaviour characteristic, it is possible to create a symmetrical dual-key cryptography. Furthermore, in this innovative solution, the high inductance value of the traditional Chua circuit can be further reduced by using the dynamic effects of the coils flux linkage. The simulation results exhibit the dual-scroll attractors phase portrait, which is available for encryption features. Therefore, the data collected from the phase portrait are used as true random number generator in Python code. Instead of using algorithms, the code can create a symmetrical key for an unique chaotic cryptography. In order to build a prototype, it has been created a PCB design for the whole system. The experiment highlights the unpredictable voltage and current and validates the chaotic behaviour of the transmitter and receiver.

L-C band pass impedance matching coupling circuit for high voltage PLC applications

This paper proposes a novel L-C band pass impedance matching circuit for PLC applications coupled to a Single Wire Earth Return (SWER) network via a 1.1 nF High Voltage (HV) Coupling Capacitor (CC). The work begins with characteristic impedance prediction of various SWER conductors followed by an analysis of the theoretical LC-resonant based coupling arrangements. A key finding is that high inductance and capacitance values are required for such LC-resonant based arrangements increasing the cost of solutions. An HV CC is then analysed and its effective capacitance is demonstrated, to be impacted by its internal protection circuitry. An L-C band pass matching circuit is then designed, built and tested as per the derived capacitance of the chosen HV-CC. The proposed coupling circuit produces only −4 dB insertion loss over the targeted 50 kHz to 150 kHz band and includes off-the-self components for a commercially viable solution. The design is based on the capacitance of an HV-CC and uses of off-the-shelf components setting this work aside from comparative works, which only considered hypothetical designs using unviable component values.

An Integrated Power Module Based on the Power-System-In-Inductor Structure

This paper presents an integrated power module with the features of high power density and high efficiency. A multifunctional integrated magnetic component is designed. The component has the roles of both the filter inductor and the package of the converter. With the assist of finite-element analysis, the design and optimization of the proposed inductor are demonstrated. It has higher inductance value than the inductor used in conventional designs. The package is composed of bigger copper winding and higher thermal conductive magnetic material, leading to lower direct current resistance and better thermal performances than conventional transfer molding packaging. Benefiting from these advantages, the power module built based on the inductor can achieve higher efficiency and lower temperature rise than those based on traditional plastic packaging solution. Design of the inductor is demonstrated through the combination of analytical and simulation methods. An inductor prototype is built and used in an integrated power module to do experimental tests. Loss breakdown of the module is analyzed. The performances of the proposed power module are better than the conventional transfer molding packaging solution with the same board or other state-of-art products.

Multi-walled carbon nanotube-coated spiral coils for loss reduction in wireless power transfer systems

Realization of high efficiency and long transmission range in high-frequency wireless power transfer (WPT) systems has always been hindered by the increased resistance due to the eddy current loss occurring in the inductive coils. In this study, multi-walled carbon nanotube-coated copper (MWCNT-Cu) coils are successfully introduced to address this limitation by implementing the frequency-inert MWCNT channels along with using their high-surface areas to realize the electromagnetic shielding of the Cu substrate through multiple reflection mechanisms. At a frequency of 15 MHz, the resistance of the individual MWCNT-Cu coil was reduced to less than 40% of its original value for primitive Cu, leading to more than a four-fold increase in their quality factor. When MWCNT-Cu coils were used as the transmitting component, the transmission efficiency of the WPT system increased from 10.57% to 95.81% at a transmission distance of 4 cm and a frequency of 3.45 MHz. Finally, it was demonstrated that the loss reduction improved as the eddy current loss became more severe in coils with higher inductance values, which makes this approach promising for significantly improving the performance of inductive components in WPT applications.