Faraday Electromagnetic Induction Research Articles

Annular Electromagnetic Generator for Harvesting Ocean Wave Energy

To sustainably power ocean sensors by harvesting ocean wave energy, an annular electromagnetic generator (A-EMG) based on the principle of Faraday electromagnetic induction is proposed in this paper. The specific structure and working principle of the generator are introduced. The distribution of the magnetic field in the coil, the variation in the induced voltage and the influence of the coil parameters on the output were simulated by the COMSOL Multiphysics software version 6.0. At the same time, an experimental platform was built to test the output characteristics of the generator. Through a comparative study of the capacitor’s charging characteristics, the optimal connection mode between the multiple groups of coils of the generator was preliminarily verified. Finally, the six-degree-of-freedom (6-DOF) platform was used to simulate various wave motion parameters, and the feasibility of the generator for supplying power to ocean sensors was verified.

Design and Characteristic Analysis of Magnetostrictive Vibration Harvester with Double-Stage Rhombus Amplification Mechanism

Vibration energy harvesting is a new alternative to lithium battery power for low-power devices, attempting to recover wasted or lost vibration energy to generate electricity. Magnetostrictive-based energy harvesting exploits the coupling properties of the Villari and Faraday electromagnetic induction effects to achieve mechanical–magnetic–electric energy conversion. In order to better apply to the actual vibration environment, such as buses, and improve the ability to capture low-frequency vibration energy, a double-stage rhombus vibration energy harvesting device, based on Terfenol-D rods, was developed. By establishing an analytical model of the force amplification ratio of the harvesting device, the design is optimized using the Single-Objective Genetic Algorithm, and the safety and pre-magnetization layout methods are analyzed by Finite Element Analysis. The output characteristics of the prototype, including the output voltage frequency response under low-frequency regular excitation and random excitation, the effect of external resistance, and the vibration energy capture performance under random excitation, are investigated in detail through experiments. The results of the experiments showed that the peak output power of the fabricated prototype was 1.056 mW at 30 Hz operating frequency, the energy harvesting capability reached 41.4 μW/N, and the peak open circuit voltage and output power were 2.92 V and 266 mW, respectively, under random excitation. Practical application test results showed that the peak voltage generated was 1.06–1.51 V when the excitation level was 2.2–4.9 m/s2. The comparative study indicates that the output performance of the proposed double-stage rhombus magnetostrictive vibration energy harvesting system is a great improvement over the proposals of existing literature.

Probing the reheating phase through primordial magnetic field and CMB

Inflationary magnetogenesis has long been assumed to be the most promising mechanism for producing large-scale magnetic fields in our universe. However, generically, such models are plagued with either backreaction or strong coupling problems within the standard framework. This paper has shown that the reheating phase can play a crucial role in alleviating those problems along with CMB. Assuming the electrical conductivity to be negligible during the entire period of reheating, the classic Faraday electromagnetic induction changes the magnetic field's dynamics drastically. Our detailed analysis reveals that this physical phenomenon not only converts a large class of magnetogenesis model observationally viable without any theoretical problem but also can uniquely fix the perturbative average inflaton equation of state, $\omega_{\phi} = (p+2)/(p+2)$ during reheating given a specific value of the large scale magnetic field. This observation hints the inflaton to assume the potential of form $V(\phi) \sim \phi^p$ near its minimum with $p \gtrsim 3.5$ if one considers the limit of the present-day strength of the large scale magnetic field to be $\mathcal{P}_{B0}^{\frac{1}{2}} \gtrsim 10^{-18}$ G. Our analysis opens up a new avenue towards constraining the inflationary and magnetogenesis model together via reheating.

Effective theory of inflationary magnetogenesis and constraints on reheating

Effective theory framework based on symmetry has recently gained widespread interest in the field of cosmology. In this paper, we apply the same idea on the genesis of the primordial magnetic field and its evolution throughout the cosmological universe. Given the broken time-diffeomorphism symmetry by the cosmological background, we considered the most general Lagrangian of electromagnetic and metric fluctuation up to second order, which naturally breaks conformal symmetry in the electromagnetic (EM) sector. We also include parity violation in the electromagnetic sector with the motivation that has potential observational significance. In such a set-up, we explore the evolution of EM, scalar, and tensor perturbations considering different observational constraints. In our analysis we emphasize the role played by the intermediate reheating phase which has got limited interest in all the previous studies. Assuming the vanishing electrical conductivity during the entire period of reheating, the well-known Faraday electromagnetic induction has been shown to play a crucial role in enhancing the strength of the present-day magnetic field. We show how such physical effects combined with the PLANCK and the large scale magnetic field observation makes a large class of models viable and severely restricts the reheating equation of state parameter within a very narrow range of 0.01 < ωeff < 0.27, which is nearly independent of reheating scenarios we have considered.

In-Plane-Sense Magnetometer Based on Torsional MEMS With Vertically-Interlaced Combs via Self-Alignment Technique

We present a MEMS magnetometer based on the Faraday electromagnetic induction principle that works in the torsional resonance mode to sense in-plane magnetic fields. As for the device design and fabrication, a self-alignment technique is introduced to realize vertically-interlaced combs used for electrostatic driving for a torsional frame structure. In order to directly acquire relatively pure resonance characteristics of devices, an electromagnetic detection means with differential outputs is proposed to suppress the parasitic feed-through effect existing in the normal electrostatic-detection. Based on magnetic response tests, the proposed device has the measured sensitivity of 491 mV/mT with the non-linearity of 0.40% and the resolution of 6 μT under atmospheric pressure. Featured with the quasi-zero power consumption (75 nW), the measurement bandwidth without mechanical bandwidth limits, and the wide dynamic range (98 dB), this in-plane-sense device constituting as an essential for a 3-axis MEMS magnetometer has wide application prospects in automotive and portable electronics.

Finite element analysis method for electromagnetic induction to telecommunication line by MAGLEV train

AbstractWhen a magnetic levitation rail carrying a superconducting coil moves at high speed, an electromagnetic induction voltage is generated in the surrounding telecommunication line due to Faraday's electromagnetic induction. This phenomenon is analyzed by AC/DC module of COMSOL multiphysics. The telecommunication line is modeled for a common mode flowing in a loop between the telecommunication line and the ground. As a result, we devise a method to calculate the induced voltage to the telecommunication line loop by differentiating in position the position dependency of the superconducting coil with respect to the magnetic flux linking the telecommunication line loop. In addition, to confirm the validity of the calculation method in COMSOL, we compare flux linkages for a model on the ground surface and a model in the complete free space, and also compare the results calculated with MATLAB by modeling with a lumped constant circuit and the results calculated with COMSOL.

Faraday induction from point-charge fields

Interpreting Faraday's law of induction has been a challenge for students, because this law involves abstract and sophisticated concepts such as the magnetic flux, given by a surface integral, and the electromotive force, given by a line integral. Besides that, Faraday's law is not clear with respect to the sources of the different fields of force, electric and magnetic, involved simultaneously in the phenomenon of induction. We discuss Faraday's electromagnetic induction through the magnetic and electric fields of point-charges in a quasistatic regime. From this perspective, we show that the results of Faraday's experiments that led to the discovery of electromagnetic induction can be understood in terms of the electric acceleration and velocity fields of point charges.

Comprehensive Analysis of the Energy Harvesting Performance of a Fe-Ga Based Cantilever Harvester in Free Excitation and Base Excitation Mode.

Vibration energy harvesting attempts to generate electricity through recycling the discarded vibration energy that is usually lost or dissipated, and represents an alternative to traditional batteries and may even lead to reliable self-powered autonomous electronic devices. Energy harvesting based on magnetostrictive materials, which takes advantage of the coupling characteristics of the Villari effect and the Faraday electromagnetic induction effect, is a recent research field of great interest. Aiming to develop a new type of magnetostrictive energy harvester using Fe-Ga alloy, which is suitable for harvesting the vibration energy from base excitations and free excitations, a Fe-Ga based cantilever harvester was proposed. The energy harvesting performance of the harvester prototype, including its resonance characteristics, open-circuit output voltage-frequency response and amplitude characteristic under base excitation, influence of external resistance, energy harvesting performance under free excitation, the function of pre-magnetization and so on was studied systematically and carefully by experiments. In terms of the volume power density, the harvester prototype without pre-magnetized magnet when in series with the optimal resistor load displays a value of 2.653 mW/cm3. The average conversion efficiency without a pre-magnetic field is about 17.7% when it is in series with a 200 Ω resistance. The energy harvesting and converting capability can therefore be improved greatly once the Fe-Ga beam is highly pre-magnetized. The prototype successfully lit up multi-LEDs and digital display tubes, which validates the sustainable power generation capacity of the fabricated prototype.

Effects analysis of bias and excitation conditions on power output of an environmental vibration energy harvesting device using Fe-Ga slice

With the advent of low power VLSI designs and the mass manufacture of CMOS, the power consumption of wireless sensor nodes has been significantly reduced from mW to μW. This opens up a new and interesting research field, that is, the possibility of converting environmental vibration energy to electrical energy for supplying power to the sensors. In this paper, using magnetostrictive materials slice, that is Fe-Ga alloy, a device for harvesting environmental vibration energy is designed and tested. Compared with piezoelectric materials and Terfenal-D alloy, Fe-Ga alloy offers excellent properties for surviving in tough ambient vibration conditions, including higher energy conversion efficiency, longer life cycles, excellent toughness, reduced depolarization and higher flexibility, etc. The designing of vibration energy harvesting process is based on the coupling characteristics of magnetostrictive inverse effect and Faraday electromagnetic induction. The device consists of a Fe-Ga alloy cantilever beam with a magnetostrictive direction throughout the length. It has magnetostrictive inverse effect during vibration and the internal magnetization state will change. A cantilever beam is surrounded by a pickup coil and voltage is induced due to the magnetic field according to Faraday's law. The energy conversion principle among mechanical, magnetic and electric energy is described through a dynamic equation of motion and in conjunction with an electromagnetic conversion equation. The influence law of bias and excitation conditions on output voltage, power and other characteristics of device are investigated in comprehensive experiments. By knowing these influence laws, it is possible to choose an appropriate number of pick up coil for a definite load resistance, to set an appropriate working frequency range, pre-tightening force and pre-magnetized magnetic field such that a maximum power can be harvested. The results derived here can be used as a design guideline for future studies in optimal design and the modeling of vibration energy harvester and force sensor.

High-frequency magnetodielectric response in yttrium iron garnet at room temperature

Magnetic and dielectric properties of Yttrium Iron Garnet are measured over a frequency ranging from 0.5 GHz to 10 GHz with a magnetic field applied parallel to the propagation direction of the microwave. At the same time, the magnetodielectric phenomena are detected quantitatively. The maximum amplitude of the magnetodielectric coefficient is acquired at the ferromagnetic resonance frequency, and the value is up to 1.2% with the magnetic field of 1500 Oe applied. The phenomena have been explained by the Faraday's electromagnetic induction of the precession of the magnetic moments in the electromagnetic field at the ferromagnetic resonance frequency.

Using analog instruments in Tracker video-based experiments to understand the phenomena of electricity and magnetism in physics education

Tracker is a piece of freeware software, designed to use video recorded images of the motion of objects as input data, and has been mostly applied in physics education to analyse and simulate physical phenomena in mechanics. In this work we report the application of Tracker to the study of experiments in electricity and magnetism using analog instruments for electrical signal measurements. As we are unable to directly video-track the motion of electrons in electric circuits, the angular deflections of the instruments’ pointers were video captured instead. The kinematic variables (angular position as a function of time) had to be related to the electrical ones (voltages and currents as a function of time). Two well-known experiments in physics teaching, the RC circuit for charging and discharging a capacitor and Faraday electromagnetic induction, were chosen to illustrate the procedures. The third experiment analysed and modeled with Tracker was the rather well-known electromagnetic retardation of disk- or cylinder-shaped magnets falling inside non-magnetic metallic pipes. Instead of metallic pipes we used an aluminum plate with an arrangement of a couple of parallelepiped-shaped magnets falling parallel to the plate. In the three cases studied, the experimental and the Tracker simulation results were in very good agreement. These outcomes show that it is possible to exploit the potential of Tracker software in areas other than mechanics, in areas where electrical signals are involved. The experiments are inexpensive and simple to perform, and are suitable for high school and introductory undergraduate courses in electricity, magnetism and electronics. We propose the use of Tracker combined with analog measuring devices to explore further its applications in electricity, magnetism, electronics and in other experimental sciences where electrical signals are involved.

DESARROLLO Y DISEÑO DE UN SISTEMA DE ALIMENTACIÓN ELÉCTRICA PARA LOS EQUIPOS DE VIGILANCIA INTELIGENTE EN REDES INTELIGENTES

To solve the power supply problems of the distributed intelligent monitoring equipment in smart power grids, this paper analyzed the shortcomings of current power supply and studied an energy-obtaining power supply based on electromagnetic induction principle. Firstly, special magnetic materials were utilized to make energy-obtaining module. Power cables and power electric wires were used to pass through the Induction coil, the power of the primary side was inducted to the second side by the law of Faraday electromagnetic induction. Then, energy management module successively rectified and filtrated AC power output from energy-obtaining module and DC/DC was converted into 5V power supply. Lithium battery (LB) was taken as standby power module to solve the dead zone of traditional energy-obtaining power supply, and it was ensuring the reliability of the entire power system. Finally, power management module based on STC15F2K60S single chip could reasonably distribute energy management module and standby module as working order of output power by monitoring battery voltage and output voltage, two modules can cooperate closely, that output voltage and current can supply intelligent monitoring equipment. A large number of experiments indicated that this battery could stably output power of DC5V and 5W within the range of 0~1000A and the power of energy management module and standby module switched smoothly, did not destroy the structure of the primary side of the power system, it cost inexpensively and was easily to install, satisfying the power supply requirements of intelligent monitoring equipment.

Tesla: Inventor of the Electrical Age, by W. Bernard Carlson

Tesla: Inventor of the Electrical Age, by W. Bernard Carlson. Princeton, Princeton University Press, 2013. xiii, 500 pp. $29.95 US (cloth). The inventor of the alternative current (AC) motor that forms the basis of electrical power supply ended up relatively unknown. Popular culture, however, would eventually recast him in mythical proportions, thereby skewing the historical record. Carlson's fascinating biography of Nikola Tesla thus sheds new light on the inventor, explaining his contributions to applied science and teasing out the basis of popular myths. Carlson's textured argument combines Tesla's background, his social interactions, thought process, inventions, together with the visionary yet impractical conceptualizations that contributed to create the Tesla myth. To do so, Carlson uses the sociology of invention as a framework that examines inventors' cognitive processes and emotional expressions as they construct their work. Tesla's originality, Carlson finds, consisted in not separating the two processes, thus departing from the practices identified in other inventors. As he did in his earlier studies of Edison and Graham Bell, Carlson interweaves expertly the biographical elements of his subject with the latter's science. Biographers often choose to emphasize the context of inventors' lives over the scientific aspect. Carlson, however, has opted for both, which helps explain the length of his detailed work, one as concerned with the intricate business dealings of the inventor as his peculiar behavior. Born in the nineteenth century of Serbian background, Nikola Tesla belongs to a generation of Central European scientists and engineers who eventually emigrated to the United States in search of success. Carlson is particularly careful in weighing cultural differences in light of Tesla's brief work at Edison's laboratories. He stresses that the nature of Tesla as an inventor with an ego should also come into consideration lest anyone claim a conflict between him and Edison. Carlson's measure discussion is especially noticeable in his technical explanations of Tesla. First reminding readers of the importance of Faraday's electromagnetic induction, and its relevance to Tesla's contributions, the author further frames the existing knowledge that surrounded Tesla's decision to work on AC in 1878. In so doing, Carlson shows that Tesla's choice involved a conceptual approach to an electric motor as a system rather than a single unit. Such a cognitive style contrasted with Edison, who was more adjusted to tinkering. As Carlson points out on multiple occasions, Tesla did not fit the mold of the brilliant inventor with limited business acumen. In fact, the father of AC understood the need for showcasing, as exemplified in the famous picture (a montage, it turns out) of the inventor reading quietly beneath giant lightning bolts. Not everything in the book will please Tesla enthusiasts. Carlson's rigorous investigation, for example, dispels the myth of a vendetta between banker J. P. Morgan, Edison, and Tesla, showing instead an investor who simply lost interest in the Serbian emigre's work. Similarly, the wilder claims about Tesla's magnetic work and related speculation find little space in Carlson's book because it lacks enough documentation that would lend itself to historical analysis. …

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 °.

Theory Design Research and the Application Prospect of the Future for the Ever Moving Car

Using faraday electromagnetic induction principle will car each wheel as a generator. For car generates its own energy recovery; In the front of car set up a blade, It can recovery the wind power what automobile driving produced, For wind power generation, So that it can recover the energy maximum for the car itself. Because of the two kinds of energy all are car generates its own energy, so it can not recovery completely, in addition to there is power loss in the other part of the car, So it needs to the energy loss and power loss for supplement, I choose the solar energy used as supplementary energy that finally achieve the purpose of "ever moving".