Theory Of Electromagnetic Induction Research Articles

Solenoid Engine

Given the impact on the environment as well as financial considerations like the gradually rising cost of liquid fossil fuels, maintenance, and other costs, electric vehicles are becoming a more and more appealing option to vehicles with combustion engines. Due to the fact that these cars are well renowned for having zero emissions and being fueled by renewable energy. The project's goal is to replace the current electric motor with an alternate electric vehicle primary mover. Generally speaking, EVs are propelled and controlled by the fusion of electrical, electronic, and mechanical components, but their primary propulsion system is its electric motor. By transforming electrical energy into kinetic energy, an electric motor operates according to the electromagnetic induction theory. An electric motor's primary function is energy conversion, and this actuator is widely used in most EV designs. Therefore, the electric motor will be replaced with a solenoid as the prime mover. A solenoid prototype is created, constructed, and tested for this. A kicking mechanism will be made of the solenoid. A solenoid has been studied as a shooting mechanism in prior investigations. One study looks into the solenoid as the best kicking mechanism. The solenoid was created and optimised in the other investigation. A prototype solenoid is created and tested in this study.

Exploration and Practice of Teaching Mode of Motor Design Course Based on Online and Offline Mixed Mode

The course of motor design is highly theoretical, and its basic principle is based on the relatively abstract theory of electromagnetic induction, which is a comprehensive subject. Because electromagnetic theory is very abstract and the analysis is complex, students generally think that this subject is difficult to learn and lacks enthusiasm for learning. Through the construction of online and offline resources of this course, the learning effect of students can be greatly promoted, the self-learning ability of students can be enhanced, the learning interest of students can be improved, and the professional ability can be increased.

Corrosion fault identification model of substation grounding grid based on PSO-LS-SVM

As one of the important equipment to ensure the normal operation of substation, the performance of grounding grid has been highly concerned. In recent years, researchers propose that the theory of electromagnetic induction can be used to diagnose and identify the corrosion fault of substation grounding grid. In this paper, a fault classification model based on LS-SVM optimized by PSO is proposed to identify the corrosion fault of grounding grid. Firstly, the wavelet packet transform principle is used to filter the original data, and the wavelet packet energy is used to construct the fault eigenvalue as the input of the fault classification model. Based on LS-SVM, a corrosion fault classification model is constructed, and particle swarm optimization method is used to optimize the parameters of the model, which solves the problem of traditional SVM parameter optimization. Through the practical application in substation, the model proposed in this paper can identify the corrosion of grounding grid conductor without excavation and power failure, which provides an effective scheme for engineering application.

Energy Regeneration From Electromagnetic Induction by Human Dynamics for Lower Extremity Robotic Prostheses

Wearable robotic devices often need electrical energy. An interesting idea is to collect mechanical energy during walking and convert it into electrical energy to recharge these devices directly. In this article, we built a light-weight robotic prosthesis (1.3 kg) with the feature of self-charging. During stance phase, the prosthetic ankle joint with damping, is driven by human dynamics. The rotated ankle joint backdrives the motor, and the motor works as a generator according to the electromagnetic induction theory. Five subjects participated in experiments to verify the feasibility and five speeds walking were studied (0.7, 0.9, 1.1, and 1.3 m/s treadmill speeds and one self-selected outdoor walking speed). Experimental results demonstrate that the electrical regenerative energy per step is 1.53 $\pm \;\text{0.29}\,\text{J}$ on average. Meanwhile, an average consumed energy per step of the robotic prosthesis is 4.64 $\pm \;\text{0.15}\;\text{J}$ , which means 33 $\pm \;5\%$ energy can be returned to the active prosthesis (battery, 24 $\,\text{V}$ , 2.6 $\,\text{Ah}$ ).

Magnetotelluric Apparent Resistivity Tensors for Improved Interpretations and 3‐D Inversions

AbstractThe complex magnetotelluric (MT) apparent resistivity tensor can be decomposed into two real tensors, the apparent resistivity and the resistivity phase tensors, which represent relationships between the observed electric field at a point on the Earth's surface and an associated apparent current density. We explain the differences between these tensors and conventional estimates of apparent resistivity and phase for simple resistivity environments and demonstrate, using canonical models in 1‐D and 2‐D environments, that both tensors are more sensitive to vertical and horizontal resistivity gradients than their conventional counterparts. The properties of the new tensors are explained using electromagnetic induction theory and the effects of associated charges at resistivity boundaries. We introduce a new way to plot tensor ellipses, which brings significant improvements to the interpretation of MT data, using appropriate visualization software. The apparent resistivity tensor gives information about the magnitude and direction of apparent resistivity subsurface structures and has a strong response to vertical resistivity contrasts. The resistivity phase tensor is highly sensitive to vertical boundaries and the associated fields in the TM mode. It is also free from static distortions under the same conditions implied for the conventional phase tensor. These findings have prompted a study in the potential of the new tensors for 3‐D inversions. The results from a 3‐D inversion of a canonical oblique conductor straddling two quarter spaces show distinct improvements in resolving the boundaries of the conductor and open a promising field for future studies.

Unified Theory of Electromagnetic Induction and Magnetic Resonant Coupling

SUMMARYThe difference between electromagnetic induction and magnetic resonant coupling was pointed out in the first proposal of electromagnetic resonant coupling. However, there was no clear technical comparison between the two methods. Therefore, in this study, five circuits are compared by using a phasor diagram, which is a basic and well‐known method in electric circuit theory. The transition from typical electromagnetic induction to magnetic resonant coupling is shown. The mechanism of the high efficiency and high‐power transfer across a large air gap and displacement is discussed, where the primary‐ and secondary‐side resonant frequencies are the same. From the above discussion, we conclude that when the specific conditions of electromagnetic induction are satisfied, the wireless power transfer can be categorized as electromagnetic resonant coupling. The unified theory of electromagnetic induction and magnetic resonant coupling is verified through experiment.

A physical model for low-frequency electromagnetic induction in the near field based on direct interaction between transmitter and receiver electrons.

A physical model of electromagnetic induction is developed which relates directly the forces between electrons in the transmitter and receiver windings of concentric coaxial finite coils in the near-field region. By applying the principle of superposition, the contributions from accelerating electrons in successive current loops are summed, allowing the peak-induced voltage in the receiver to be accurately predicted. Results show good agreement between theory and experiment for various receivers of different radii up to five times that of the transmitter. The limitations of the linear theory of electromagnetic induction are discussed in terms of the non-uniform current distribution caused by the skin effect. In particular, the explanation in terms of electromagnetic energy and Poynting’s theorem is contrasted with a more direct explanation based on variable filament induction across the conductor cross section. As the direct physical model developed herein deals only with forces between discrete current elements, it can be readily adapted to suit different coil geometries and is widely applicable in various fields of research such as near-field communications, antenna design, wireless power transfer, sensor applications and beyond.

Aprendizaje de la teoría de inducción electromagnética en cursos universitarios de física general. Una enseñanza por resolución guiada de problemas

Este estudio describe el diseño, implementación y efectividad de una secuencia de enseñanza sobre inducción electromagnética (IEM) para primer curso de grados de ciencias e ingeniería. Dicha secuencia ha sido diseñada teniendo en cuenta diversos aspectos tales como: los intereses, actitudes y valores de los estudiantes y los estándares del currículo; los resultados de los estudios empíricos sobre concepciones y razonamientos de los estudiantes, y, también, las contribuciones relativas a cómo se aprende y se enseña en el ámbito de las ciencias. La evaluación de la secuencia se ha realizado de forma «interna», comparando los resultados obtenidos por el grupo «experimental» de estudiantes antes y después de implementar la secuencia; también de manera «externa», comparando los resultados de ese grupo con uno de control. Los resultados obtenidos en el grupo experimental indican que la aplicación de la secuencia diseñada ha contribuido a la mejor comprensión de algunas ideas clave de la IEM.

Research on the Impact of Screen Properties on Eddy Current and Flux in End Region of a Large Air-Cooled Turbo-Generator

Large turbo-generators are an important energy conversion device in power stations. Once a failure occurs in the turbo-generator, it not only affects the reliability of the power system but also causes enormous economic losses. Nowadays, large air-cooled turbo-generators have developed. The safe and steady operation of turbo-generator is important for the electric power system. Leakage magnetic field is a potential hazard in end region of a turbo-generator. Leakage magnetic flux could cause eddy current to be induced in the metal component of end region, which leads to heat generation. In this paper, aiming at the complex end structure of turbo-generator, a three dimensional (3-D) mathematic model used for electromagnetic field calculation in end region of a 150-MW air-cooled turbo-generator is established. Finite element method is used to calculate the 3-D magnetic field in end region of a turbo-generator. Magnetic flux leakage testing is conducted under noload condition. It shows that there is a good agreement between the theoretical simulation and the experimental results. Eddy current loss of end parts is gained based on the electromagnetic induction theory.

電磁誘導方式と磁界共振結合方式の統一理論

SUMMARY The difference between electromagnetic induction and magnetic resonant coupling was pointed out in the first proposal of electromagnetic resonant coupling. However, there was no clear technical comparison between the two methods. Therefore, in this study, five circuits are compared by using a phasor diagram, which is a basic and well-known method in electric circuit theory. The transition from typical electromagnetic induction to magnetic resonant coupling is shown. The mechanism of the high efficiency and high-power transfer across a large air gap and displacement is discussed, where the primary- and secondary-side resonant frequencies are the same. From the above discussion, we conclude that when the specific conditions of electromagnetic induction are satisfied, the wireless power transfer can be categorized as electromagnetic resonant coupling. The unified theory of electromagnetic induction and magnetic resonant coupling is verified through experiment.

Addressing students’ difficulties with Faraday’s law: A guided problem solving approach

In traditional teaching, the fundamental concepts of electromagnetic induction are usually quickly analyzed, spending most of the time solving problems in a more or less rote manner. However, physics education research has shown that the fundamental concepts of the electromagnetic induction theory are barely understood by students. This article proposes an interactive teaching sequence introducing the topic of electromagnetic induction. The sequence has been designed based on contributions from physics education research. Particular attention is paid to the relationship between experimental findings (macroscopic level) and theoretical interpretation (microscopic level). An example of the activities that have been designed will also be presented, describing the implementation context and the corresponding findings. Since implementing the sequence, a considerable number of students have a more satisfactory grasp of the electromagnetic induction explicative model. However, difficulties are manifested in aspects that require a multilevel explanation, referring to deep structures where the system description is better defined.

Analysis of Theory and Model of Background Magnetic Field of High-Spinning Projectile

At present, methods of the navigation and the attitude measurements of projectile utilizing the magnetic fields are facing the interference from the BMF (background magnetic field). The principle and mathematical model of the BMF for the spinning projectile are been researched to realize the high accuracy measurement of the geomagnetic field on projectile. The composition and jamming mechanism of the projectile's BMF are derived with the Faraday electromagnetic induction theory. High precision compensation model of the geomagnetic measurement is established by synthesizing the magnetic sensor error model. Based on the idea of the error transfer, the attitude measuring errors caused by the BMF are analyzed and the error calculation formulas are given. On this basis, numerical simulation is conducted combining with projectile's flight rules. The results show that the influence of attitude angle measuring precisions caused by the background interference magnetic field are much bigger than the errors caused by the sensor noise and the established compensation model has obvious effect. Besides, the effective BMF compensation of geomagnetic measurements on the projectile must be conducted if the attitude angle measurement error is in requirements within ±1 °.

Analysis of magnetic satellite data to infer the mantle electrical conductivity of telluric planets in the solar system

Space missions launched to study the solar system planets generally involve a magnetometer in the scientific payload. The magnetic data may be used to infer the electrical conductivity of a planet's mantle using electromagnetic induction theory. The application of induction analysis on terrestrial bodies of the solar system other than the earth is challenging because of little information available about the external inducing sources. Here, we present a method to analyze magnetic data from these space missions that determines the geometry of the dominant external inducing magnetic field and deals with the inherent gaps in the satellite magnetic time series. We tested the approach on Earth synthetic satellite data generated to prepare the ESA magnetic mission Swarm and demonstrated the feasibility for recovering the 1-D conductivity part of the model used to generate these data. The analysis of real data from the Danish Ørsted magnetic mission provided satisfactory conductivity profiles of the Earth's mantle.

在线校验用标准电流互感器的设计

该文介绍了一种在线校验用标准电流互感器的设计。该电流互感器基于电磁感应原理，利用双铁芯工作，并引入了无源补偿，具有开合式结构，能够在线安装，抗干扰能力强，其输出为模拟小信号，能直接被采集系统采集。实验结果表明，其精度优于0.05级，并且在开合50次后，仍能满足0.05级的标准要求。 This paper introduces the design of a standard current transformer for on-line calibration. The current transformer based on the electromagnetic induction theory works with dual cores and has the passive compensation circuit. It not only can be installed on line due to the open-close structure, but also possesses a strong anti-jam capability. The output of the current transformer is small analog signal which can be picked up directly by acquisition system. The testing results show that the accuracy class of the current transformer is better than 0.05 and it still can meet the standard when opened and closed 50 times.

Fine analysis on advanced detection of transient electromagnetic method

Fault fracture zones and water-bearing bodies in front of the driving head are the main disasters in mine laneways, thus it is important to perform their advanced detection and prediction in advance in order to provide reliable technical support for the excavation. Based on the electromagnetic induction theory, we analyzed the characteristics of primary and secondary fields with a positive and negative wave form of current, proposed the fine processing of the advanced detection with variation rate of apparent resistivity and introduced in detail the computational formulae and procedures. The result of physical simulation experiments illustrate that the tectonic interface of modules can be judged by first-order rate of apparent resistivity with a boundary error of 5%, and the position of water body determined by the fine analysis method agrees well with the result of borehole drilling. This shows that in terms of distinguishing structure and aqueous anomalies, the first-order rate of apparent resistivity is more sensitive than the second-order rate of apparent resistivity. However, some remaining problems are suggested for future solutions.

Fourier domain calculation of terrain effects in marine MT

SUMMARY Magnetotelluric surveys on the seafloor have become an important part of marine geophysics in recent years. The distorting effects of topographic relief on the electromagnetic fields can be far-reaching, but local terrain is also important. Thus, computational techniques that can treat a large area containing fine-scale topography could find widespread application. We describe a new solution to the problem based on a well-established theory of electromagnetic induction in thin sheets. The procedure requires taking the Fourier transform of the integral equations derived by Dawson and Weaver in 1979, and by McKirdy, Weaver and Dawson in 1985. The equations in the transformed electric field are solved iteratively by a new technique. We prove the new iterative procedure is always convergent, whereas the original scheme diverges when the grid spacing of the discretization is small. We also give a means of correcting for distant features that need not be specified in as great detail. Preliminary tests confirm the new process is very efficient and that topographic data sets of several million points will be handled with ease.

633 電磁誘導を用いた流体式ダンパに関する研究

Many types of semiactive dampers that can have a variable damping force in order to control and reduce vibration efficiently. Most of semiactive damper have a dynamic function of switching viscosity or stiffness. In this study, a unique active damper that utilizes electromagnetic induction is developed. The active damper consists of a cylinder, piston, a by-pass pipe, electrodes, electromagnets and fluid. A resisting force is derived by the Fleming interaction across a magnetic flux and some electrodes in the by-pass pipe area. It is pointed out that the eight electromagnets are installed at around the by-pass pipe and enable to switch a value and direction of magnetic flux density. In this study, salt water instead of a functional fluid such as MR fluid. The test device of the by-pass pipe was partially manufactured in order to confirm the theory of electromagnetic induction, and to obtain adequate resisting force. Finally, the feasibility study of the damper is confirmed experimentally.

Research on an Electromagnetic Induction-Based Deep Displacement Sensor

A novel deep displacement sensor based on the electromagnetic induction theory is investigated and designed, which can directly convert the varied sliding displacement and tilt angle at any depth within the landslide mass to the variation of mutual inductance, so it has advantages, such as simple sensor structure, high sensitivity, accurate positioning of sliding surface and position, a remote, as well as real-time and automatic monitoring toward the underground landslide mass over the conventional deep displacement monitoring methods. The structure design, sensing principle, and theory modeling for the proposed sensor are presented. In order to improve the sensor's performance, the complicated relationship between the landslide mass's sliding magnitude and direction, the sensor's geometric parameters, and its corresponding mutual inductance were derived by theoretical modeling. Furthermore, a series of ground-based testing experiments and theoretical modeling simulation are conducted and compared in detail, which not only initially shows the design feasibility and modeling effectiveness for the proposed sensor, but is also useful to give an in-depth understanding of the sensor property and optimize the sensor design.

A spatially constrained 1D inversion algorithm for quasi-3D conductivity imaging: Application to DUALEM-421 data collected in a riverine plain

The efficient use of water in irrigated agricultural systems is of increasing importance given the changes in climatic patterns currently being experienced in the irrigated areas of the Murray-Darling Basin (MDB) in Australia. In previous research, electromagnetic (EM) induction instruments have been used to map the distribution of the clay content in those areas. However, describing their vertical extent and connectivity with groundwater tables or stratigraphic features such as paleochannels has not been studied adequately. One of the reasons for the paucity of research is the lack of suitable instrumentation or software to invert apparent conductivity (σa) data. The aim of this research is to demonstrate how DUALEM-421 equipment, which operates using electromagnetic induction theory, can be used to map not only the areal distribution of a prior stream channel but its vertical extent by inputting the data into a 1D spatially constrained algorithm for quasi-3D conductivity imaging. We discovered how the inversion of the apparent electrical conductivity, measured in the horizontal (HCP) and perpendicular (PRP) arrays, characterizes the Quaternary alluvial clays which dominate the riverine plain of the lower Gwydir valley, and indicates the location and extent of a prior stream channel and its sediments across Auscott Midkin field 11. We found the calculated conductivity values favorably represent the known stratigraphy of these physiographic units. Our results suggest the prior stream channel may be interconnected with a more extensive paleochannel.

Ring‐shaped composite fields

PurposeThe purpose of this paper is to reach two goals: one is to generalize the well‐studied theories of electricity and magnetism to the enrichment of deepened understanding of the general systemic yoyo model, and the other is to employ the established yoyo model to provide more refined explanations for some of the known experimental observations in physics.Design/methodology/approachThe general structure and the field characteristics of the general systemic yoyo model are employed as the basis of our exploration in this paper. Then, methods of quantitative analysis are introduced to address some of the problems encountered.FindingsAmong several new results, many important concepts, such as ring‐shaped electric fields, cylinders of equal potential intensities, yoyo resistances, yoyo capacitors, etc. are introduced and studied in some detail. Several important Laws in electromagnetic theory, such as Ohm's law, Kirchhoff's laws, etc. are generalized to the case of the general systemic yoyo model. The refined theory is applied to provide theoretical explanations for some laboratory‐observed phenomena that cannot be well illustrated by either Faraday's theory of electromagnetic induction or Lenz's law.Originality/valuePhenomena related to electricity and magnetism are explained the first time in history by using a unified model: the systemic yoyo model. At the same time, some well established Laws in physics are generalized to scenarios of this general mode with the hope that these new Laws can be applied equally well to natural and social sciences in the coming years.