Ferrite Bars Research Articles

Coil Parameter Analysis for Inductively Coupled Wireless Charging for Electric Vehicles

Wireless charging (WC) has gained popularity for the charging of electric vehicles in recent years of research, particularly dynamic wireless charging systems (DWCSs). Among the different topologies of DWCSs, this paper focuses on an inductively coupled wireless charging system (ICWCS). In this ICWCS, double-D (DD) coils create horizontal and vertical flux components between different pad configurations, which show optimal features in contrast to circular pad coils. In this work, the three-dimensional (3D) finite element technique (FEM) is used to establish the proposed design to observe the coupling coefficient, while the system design’s performance is evaluated using a circuit simulator. In the simulation, the proposed DD coil configuration is used for both the transmitter and receiver sides. It provides the maximum coupling coefficient and efficiency at perfect alignment when using an in-between air gap of 166 mm and six I-type ferrite bars on the transmitter side and five I-type ferrite bars on the receiver side. The coupling coefficient and system parameters, such as power and efficiency, are considered for different misalignments in the proposed configuration. The results of this work satisfy the Society of Automotive Engineers (SAE) J2954 Class 3 criteria. The best results obtained are on account of optimizing the ferrite core, which is achieved by varying its length and width. While varying the ferrite core’s dimensions, 0.2451, as the optimal k value, is obtained at the effective width and length of 57.5 mm and 400 mm, respectively. The simulation results of the Ansys Maxwell 3D software prove the feasibility of the proposed structure.

Analysis of Coil Systems with Non-Symmetrical Fe Backings for Electrical Vehicle Wireless Charging Applications

Wireless power transfer is a widely applied technology whose market and application areas are growing rapidly. It is considered to be a promising supplement to the conductive charging of electrical vehicles (EVs). Wireless charging provides safety, convenience, and reliability in terms of mitigating issues related to wiring, risk of tearing, trip hazards, and contact wear inherent to the conductive charging. A variety of coil structures have been researched for EV charging applications; however, most of them were of the symmetrical type. This work analyzes systems of coils possessing ferromagnetic backing with non-symmetrical geometries and compares them with the conventional symmetrical ones. Numerical FEM simulation was applied in the research. The numerical models were verified analytically and experimentally. The impact of air-gap length, longitudinal displacement, number of turns, and width of the ferrite bars on coupling factor was investigated. The results suggest that coil systems with non-symmetrical structures of ferromagnetic backings are a good alternative to the conventional symmetrical structures for wireless electrical vehicle charging applications.

Magnetic Coupling Characteristics and Efficiency Analysis of Spiral Magnetic Power Pads for Inductive WPT System

The inductive wireless power transfer system (IWPT) for electric vehicle battery charging works based on the principle of mutual induction (MI). The amount of power transfer from source to vehicle battery be contingent on the mutual inductance (MI) within the inductively coupled pads. This mutual inductance depends on the type of the inductive power pads, the distance among them, their positioning etc. This paper develops and study the inductive coupling characteristics of identical spiral circular and square inductive power pads. The coupling characteristics at various misalignments with different vertical distance between the coils is presented. In this work, the inductive power pads without using ferrite bars, and with ferrite bars are considered. The coupling characteristics of the spiral circular and square are computed using FEM simulations and validated with experimental results. This paper also investigated the power loss and efficiency analysis of the spiral inductive pads of the resonant IWPT system.

Sensor Coil System for Misalignment Detection and Information Transfer in Dynamic Wireless Power Transfer of Electric Vehicle

Wireless power transfer (WPT) technology has been applied to fields as diverse as medical, electronic devices and transportation because of its convenience, safety and aesthetics. In particular, electric vehicles (EVs) that have emerged to replace internal combustion engines, which cause environmental pollution problems, are most suitable for applying WPT. Not only does convenience increase by eliminating charging cables, but the issue of heavy batteries can also be resolved by using dynamic WPT technology, which allows charging of batteries while driving. Furthermore, if dynamic WPT technology and autonomous driving technology are applied together to EVs, the driver’s convenience with regard to charging as well as driving will be greatly improved. In this paper, we propose a multi-purpose sensor coil system for use with dynamic WPT in an EV. Sensor coils detect any misalignment between the source coil and the load coil that occurs while the vehicle is being driven. Furthermore, the proposed system uses sensor coils and ferrite bars to transfer information, such as the lanes which vehicles are being driven. By transferring information, the proposed system can provide the benefits of autonomous driving technology as well as WPT technology. We theoretically analyze the proposed method and confirm that it can play two roles through simulations and experiments.

An efficient design of LC-compensated hybrid wireless power transfer system for electric vehicle charging applications

Wireless power transfer (WPT) is the technology of transferring the electric power through a time-varying electric or magnetic field acting as a transmission medium. A combination between the inductive power transfer (IPT) and the capacitive power transfer (CPT) has been recently developed to benefit from the merits of both systems in order to realize high power transfer with high efficiency through large air gaps and misalignment distances. The output power capability of the existing designs is still limited and needs further enhancement. In this paper, a new hybrid inductive and capacitive wireless power transfer model is proposed, analyzed and simulated. The inductive part composes of a circular spiral coil integrated with a helical coil and supported with cross shape ferrite bars in order to enhance the magnetic coupling ability. The capacitive part consists of four cylindrically evacuated square plates compatible with the inductive part size to facilitate the combination process. Firstly, the system structure is designed using Maxwell-3D simulation tool, then an equivalent circuit model is derived in detail to explicate the working principle. Secondly, a 10.1 kW hybrid system is designed and simulated using MATLAB/Simulink and ANSYS/Simplorer. Excluding the inverter and the rectifier internal losses and considering only the AC losses of the coils represented in their parasitic resistance, a high resultant efficiency equal to 99.37% at a resonant frequency of 1 MHz is achieved. Generally, the results show that the hybrid system could perform better under different air gaps and misalignments than the inductive and the capacitive systems separately.

Optimal Design of IPT Bipolar Power Pad for Roadway-Powered EV Charging Systems

This article proposes a multiobjective design optimization of rectangular bipolar power pads (BPP) for dynamic inductive power transfer (IPT) with application in electric vehicles. Minimization of IPT's design cost, loss that includes core and winding, and maximization of the IPT system's tolerance against horizontal/vertical misalignment are considered as objective functions during the optimization process. The design variables of the proposed algorithm are the shield plate length and width, ferrite bar length and width, the overlapping length of the coils, and the coil width and inner length of the coil. Power electronic limitations by defining the IPT's quality factor ( 4 <; Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</sub> <; 10), maximum allowable electromagnetic field (EMF) exposure ( EMF ≤ EMF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Max</sub> ), efficiency of all possible solutions greater than 80% ( η > 80%), and upper/lower limits of design parameters are considered as the constraints of this optimization problem. The time-harmonic electromagnetic physics model of the BPP is analyzed using an finite element method magnetics (FEMM) software coupled with MATLAB. A nondominated genetic algorithm (NSGA-II) is employed as the optimization solver, in which the electromagnetic measurements from the FEMM software are used to evaluate the fitness values of the proposed objectives. The proposed BPP design optimization is applied on a 10-kW IPT system as a case study. The optimization results produced 15 Pareto optimal solutions. A validation study of two Pareto front solutions (PFS) is also presented. The Pareto optimal solutions allow the designer to select the best design parameters based on the objectives of highest priority.

A New Magnetic Structure of Unipolar Rectangular Coils in WPT Systems to Minimize the Ferrite Volume While Maintaining Maximum Coupling

In the wireless power transfer system, the transmission efficiency and power transfer capability depend on the coupling coefficient ( k). Usually, the coupling of the air-core unipolar coil system is weak. For improving k, the ferrite core is used. In traditional ferrite arrangement, the ferrite core size is kept approximately equal to the coil dimensions, which increases the overall weight and volume of the system. This brief proposes a novel and simple ferrite arrangement of unipolar rectangular coils, which maintains the maximum achievable k and minimizes the volume of ferrite used. Pythagoras' theorem is used to calculate the position and length of the ferrite bars. Furthermore, various possible ferrite arrangements are studied and compared with the proposed ferrite arrangement (PFA). The proposed arrangement saves 81.24% volume of the ferrite used with a decrement of only 6.93% in k (at the 150-mm air gap) over the traditional arrangement. Finally, a prototype of the PFA is developed, and the results are verified.

ЭЛЕКТРОННЫЙ КОМПАС ДЛЯ АВТОМНЫХ СУДОВ БЕЗ ЭКИПАЖА

Principle of action of semiconductor two-collector magnetic transistors and possibility of creation on their basis of electronic compass is covered in the article. Level of automation of marine ships navigation, appearance of the autonomous fully automated ships without a crew, requires presences aboard the ship of device giving out a not visual, but electronic signal about direction of motion. An electronic compass on the basis of magnetic sensor semiconductor elements can decide this task. There is of most interest an electronic compass, a consisting of semiconductor magnetic sensor element, electric signal on the output of which is proportional to the level of the external magnetic field, and electronic chip processing a signal. In this article the example of laboratory construction of such electronic compass is described and his descriptions over are brought. Important, that this electronic device does not have mobile mechanical parts and mechanisms. For the increase of sensitiveness of electronic sensor of the magnetic field application of reflector-absorbers of the magnetic field is offered. Ferrite bars are used in this case. Bars are disposed both-side sensor, parallell to optimum direction of the magnetic field. In the experiments it was succeeded to get the increase of sensitiveness of sensors in 400 times. The reflector-absorbers of the magnetic field also allow to improve correlation signal to noise in 100 times. An electronic compass on the basis of magnetic transistors can be also used and as an element to control the course of marine ship. If a magnetic transistors is set to direction of motion, the change of loading resistances sets the zero of tension between the collectors of magnetic transistor. At deviation of axis from the set direction, tension of one polarity appears between collectors, and in other - opposite. This tension through the system of autopilot can directly control a steering gear and automatically to maintain the set direction of motion of marine ship. Experimental descriptions over of pre-productions models of magnetic transistors and flows diagrams of compasses are brought. An experiments show that on the basis of two-collector magnetic transistors can be created electronic compass not containing mechanically moving details, that sharply promotes his reliability and durability. An electronic compass will become the obligatory attribute of future autonomous ships without a crew. He will be able not only to replace a classic magnetic compass but also to allow to realize the span-new functions of ships control.

Research on the transmission efficiency of different shielding structures of wireless power transfer system for electric vehicles

Wireless Power Transfer (WPT) charging system can cause eddy loss on the steel part and the chassis of Electric Vehicle (EV). To study different shielding structures' influence on the transmission efficiency of the WPT system, boundary conditions and assumptions of WPT model in the quasi-stationary electromagnetic field were established and finite element method (FEM) was adopted. The shielding effectiveness of ferrite plate and annular aluminum plate was investigated as well as their effects on coupling coefficient of WPT. It was found that, the setting of ferrite core enhanced the transmission field strength, improved the coupling between two coils, and increased transmit power as well as the actual eddy loss. The actual necessary shielding-area was not confined into the same-size area but distributed around the edge of the ferrite. By arranging specialized size annular aluminum plate between chassis and ferrite core, the eddy loss can be effectively shielded and an optimal transmission efficiency was reached with acceptable coupling coefficient decrease. The optimized ferrite bar structure and its EMC characteristics were also studied. It was also found that with equal volume, the optimized ferrite bar structure had better performance in EMC and coupling enhancement than the full ferrite plate.

A Study of Nonreciprocal Coupled Ferrite-Dielectric Image Guide Structure for Ka-band

The nonreciprocal coupled ferrite-dielectric image guide structure with the same geometry as in our previous experimental investigation has been studied numerically by finite element method in the frequency range 26–40 GHz. The ferrite element in the experiment has been inhomogeneously magnetized by using a disk-shaped permanent magnet, whose diameter is comparable with the length of the ferrite bar. Recently, we have modelled the ferrite element as homogeneously magnetized perpendicularly to the ground plane and the direction of propagation. This homogeneous magnetization represents first approximation of the real inhomogeneous one. Here we have extended the numerical examination of the nonreciprocity and as a result we have proposed a procedure for designing isolators with inhomogeneous magnetization. Also, we have investigated the influence of several parameters – permanent magnetic field strength and three ferrite material parameters (saturation magnetization, relative dielectric permittivity and dielectric loss tangent) on the nonreciprocal behavior of the coupled ferrite-dielectric structure.

Study of Nonreciprocal Coupled Ferrite-Dielectric Image Guide Structure for Ka-band

The nonreciprocal coupled ferrite-dielectric image guide structure with the same geometry as in our previous experimental investigation has been studied numerically by finite element method in the frequency range 26–40 GHz. The ferrite element in the experiment has been inhomogeneously magnetized by using a disk-shaped permanent magnet, whose diameter is comparable with the length of the ferrite bar. Recently, we have modelled the ferrite element as homogeneously magnetized perpendicularly to the ground plane and the direction of propagation. This homogeneous magnetization represents first approximation of the real inhomogeneous one. Here we have extended the numerical examination of the nonreciprocity and as a result we have proposed a procedure for designing isolators with inhomogeneous magnetization. Also, we have investigated the influence of several parameters – permanent magnetic field strength and three ferrite material parameters (saturation magnetization, relative dielectric permittivity and dielectric loss tangent) on the nonreciprocal behavior of the coupled ferrite-dielectric structure.

All-utensil domestic induction heating system

This paper proposes and implements an all-utensil domestic induction heating system, which can effectively heat utensils made by ferromagnetic conductive (FC), non-ferromagnetic conductive (NFC) and non-ferromagnetic non-conductive (NFNC) materials. The proposed system consists of a controller, a full-bridge inverter and a new sandwiched-coil structure with the primary coil located at the lower part, ferrite bars in the middle part and resonant coil in the upper part of the heater, respectively. Besides, a fixed capacitor is connected with the primary coil and a switched-capacitor array is connected with the resonant coil to ensure that the magnetic resonant coupling (MRC) can be achieved when adopting different utensils. The proposed system not only releases the current stress of the inverter but also significantly strengthens the magnetic coupling effect to boost the heating performance under a resonant frequency of 30 kHz. In the meantime, the burst firing control (BFC) is utilized to flexibly regulate the output power while retaining the maximum transfer efficiency. For exemplification, a 500 W prototype has been built for heating FC (iron), NFC (aluminum) and NFNC (ceramic) utensils with the average temperatures of 83.8, 73.1 and 76.5 °C, output powers of 484.4, 411.4 and 426.16 W, and transfer efficiencies of 96.9, 82.3 and 85.2% respectively. Both finite element analysis and experimentation are given to verify the validity of the proposed system.

Development of a Ferrite-Based Electromagnetic Wave Detector

Direct detection of hydrocarbon by an active source using electromagnetic (EM) wave termed Sea Bed Logging (SBL) has shown very promising results. However, currently available electromagnetic wave technology has a number of challenges including sensitivity and lapsed time. Our initial response to this issue is to develop a ferrite-based EM wave detector for Sea Bed Logging (SBL). Ferrite bar and copper rings in various diameters were used as detector 1 (D1). For Detector 2 (D2), toroid added with copper wires in different lengths at the centre of it were used. The first experiment is to determine the inductance and resistance for both detectors by using LCR meter. We obtained the highest inductance value of 0.02530 mH at the ferrite bar when it was paired with a 15 cm diameter copper ring and 0.00526 mH for D2 using a 100 cm copper wire placed at the centre of the toroid . The highest resistivity for D1 was measured at ferrite bar paired with a 15 cm diameter copper ring and 1.099 Ω when using 20 cm length of copper wire. The second interest deals with voltage peak-to-peak (V p-p ) value for both detectors by using oscilloscope . The highest voltage value at the ferrite bar of D1 was 25.30 mV. While at D2, the highest voltage measured was 27.70 mV when using a 100 cm copper wire. The third premise is the comparison of sensitivity and lapsed time for both detectors. It was found that D1 was 61% more sensitive than D2 but had higher lapsed time than D2.

Mesoscopic bar magnet based on ε-Fe2O3 hard ferrite

Ferrite magnets have a long history. They are used in motors, magnetic fluids, drug delivery systems, etc. Herein we report a mesoscopic ferrite bar magnet based on rod-shaped ε-Fe2O3 with a large coercive field (>25 kOe). The ε-Fe2O3–based bar magnet is a single crystal with a single magnetic domain along the longitudinal direction. A wide frequency range spectroscopic study shows that the crystallographic a-axis of ε-Fe2O3, which corresponds to the longitudinal direction of the bar magnet, plays an important role in linear and non-linear magneto-optical transitions, phonon modes, and the magnon (Kittel mode). Due to its multiferroic property, a magnetic-responsive non-linear optical sheet is manufactured as an application using an ε-Fe2O3–based bar magnet, resin, and polyethylene terephthalate. Furthermore, from the viewpoint of the large coercive field property, we demonstrate that a mesoscopic ε-Fe2O3 bar magnet can be used as a magnetic force microscopy probe.

Ultrasonic Piezonuclear Reactions in Steel and Sintered Ferrite Bars

We report the results of piezo-energy emissions in the form of neutron bursts measured during the application of ultrasounds to sintered ferrite (α-Iron) and steel bars using an original experimental device. The measurements, carried out by HDS-100GN and by a Microspec2 neutron probe, confirmed neutron emission repeatability from inert iron-rich media and the absence of gamma radiation. In addition, energy spectra of neutron emission during the application of ultrasounds are shown as well. After neutron detection, Energy Dispersive X-ray Spectroscopy (EDS) analyses were conducted, showing semi-quantitative evidences of iron decrease and the possible occurrence of nuclear reactions of a new type in correspondence to meso-craters (burns) localized on the external surfaces of the bars. Finally, similar evidences may be observed at the Earth's crust scale where well distinguishable neutron emissions and anomalous chemical changes in correspondence to major earthquakes and micro-seismic activity may be considered to explain the significant iron depletion characterising seismic areas and the Earth's crust evolution

Optimization, design, and modeling of ferrite core geometry for inductive wireless power transfer

This paper presents a new design of ferrite core made of ferrite bars positioned in radial geometry. New core design is used in inductive wireless power transfer where the optimal design of ferrite bars was analyzed. Numerical simulations of seven ferrite bars geometries were performed in 3D models using Comsol Multiphysics in terms of the coupling coefficient. Two optimal designs of three and nine ferrite bars geometries were used for parameterization of geometric parameters. Both simu- lations of three and nine ferrite bars geometries were verified by measurements. Optimal design of nine ferrite bars geometry is proposed for use in wireless power transfer because of low consumption of ferrite material. Ferrite bars geometry was also used as a magnetic shield to reduce magnetic fields which may interfere with the electronics nearby. Magnetic flux density in ferrite bars is low enough that prevents ferrite bars from the saturation. The angular alignment of optimal design of nine ferrite bars on the transmitter and receiver side was negligible as the difference in the coupling coef- ficient was 0.13%. Advantages of using optimal design of nine ferrite bars geometry are: high value of the coupling coefficient, low consumption of ferrite material, and reduced weight.

Optimization of Tool Wear Using Coupled RSM-GA Approach in Turning of Stainless Steel AISI 304 with Magnetic Damping of Tool Shank

Tool wear, especially flank wear, is a major concern in the manufacturing industry. Increased tool wear is caused by chatter and leads to increased surface roughness, reduced productivity and higher operating costs. It is more pronounced in the machining of difficult to cut materials such as stainless steel, tool steel, Inconel and hardened Ti alloys. Additionally, unpredictable tool wear can lead to frequent shutdowns of the machining process making it difficult for full automation. Therefore, to increase productivity and to reduce costs associated with increased and unpredictable tool wear, numerous research studies have been carried out. In this research, two permanent ferrite bar magnets of 1500 Gauss strength were used to dampen the vibration of the tool shank in the turning of stainless steel AISI 304 using titanium nitride (TiN) coated carbide inserts. Mild steel fixtures were used to place the magnets beside and below the tool shank in the carraige of a Harrison M390 engine lathe. The tool overhang was kept constant at 120 mm. A small central composite design (CCD) approach in response surface methodology (RSM) was used to model the tool wear as a response of the three primary cutting parameters: cutting speed, feed, and depth of cut. Design Expert software (version 6) was used to generate the 14 experimental runs needed to develop and verify the empirical mathematical model of tool flank wear. The resultant tool flank wear was measured using both optical and scanning electron microscopes (SEM). Finally, an empirical quadratic mathematical model of tool wear was found. This model was then used as the objective function in the optimization of tool wear using genetic algorithms (GA). The optimization results predicted that the minimum tool wear was 0.0427 mm. This prediction was subsequently validated experimentally.

Loss Analysis of Circular Wireless EV Charging Coupler

With the demand for mass-produced commercial electric vehicles (EVs) growing over the last few years, the requirement for EV charging will increase, with continued growth as the number of on-road EVs increases. The EV wireless charging technology offers more flexibility than traditional plug-in charging technology for the following reasons: 1) full automation; 2) fast response; 3) high-power capacity; and 4) safety. The charging coupler is the key component in an inductive wireless charging system. This is a medium to high-frequency transformer (20 kHz), the core loss and the copper loss have to be considered carefully since these will affect the efficiency of the coupler. This paper presents the analysis of a circular coupler with ferrite bar cores and includes the analysis of the core loss considers the sizing of the device. The device is circular on a vertical axis and the air gap is large since there has to be a gap between the charger and vehicle. Therefore, the variation of the transformer coupler diameter is considered in terms of primary/secondary linkage for a fixed air gap. Resonance is used to improve the power factor and boost the transformer output voltage. The core loss is analyzed using finite element analysis in ANSYS Maxwell and the copper loss assumed the use of Litz wire.

Development of a New High Sensitive Eddy Current Sensor

Eddy current testing (ECT) is one of the most representative nondestructive testing methods for metallic materials, parts, structures and so on. Operating principle of ECT is based on two major properties of the magnetic field. One is that alternating magnetic field induces eddy current in conducting materials. Thereby, an input impedance of the magnetic field source, i.e., electric source, depends on the eddy current path. Second is that the magnetic field distribution depends not only on the exciting but also on the reactive magnetic fields caused by the eddy currents in targets. Former and latter are the impedance sensing and magnetic flux sensing types, respectively.This paper concerns with an optimization of a new magnetic flux sensing type sensor named coil. Exciting and sensing coils are composed of shape coil and a finite length solenoid coil wound on ferrite bar, respectively. Development of this coil fully depends on the 2D and 3D finite elements method modeling. According to the simulation results, we have worked out two types of coils. Practical experiments reflect the validity of both simulation and design aims, quite well. Thus, we have succeeded in developing coil having a higher sensibility compared with that of conventional one.

Atomic and isotopic changes induced by ultrasounds in iron

Electron microscopy and neutron activation techniques are used to map the elemental and isotopical compositions of ferrite bars where the emission of neutron bursts and the formation of dark regions were reported after ultrasound irradiation. Anomalous values are found in these regions. The original concentrations of natural isotopes of copper and zinc are deduced; the occurrence of pressure-induced nuclear reactions is inferred while the cavities are suggested to act as nuclear micro-reactors. The general characteristics of these phenomena are considered a support to the existence of a new type of reactions, called deformed space–time reactions (DST-reactions).