Induced Output Voltage Research Articles

Modeling Rogowski Coils for Monitoring Surge Arrester Discharge Currents

Rogowski coils (RCs) are widely used to measure power or high frequency currents based on their design. In this paper, two types of RCs that are circular (traditional) and cylindrical shapes wound using wire covered by varnish are constructed. This construction is carried out to be suitable for monitoring the discharge current of the surge arrester installed in the distribution system. Concerning high frequency RC modeling for both types considering transfer function is introduced. Self-integrating for both types is attained. Therefore, the experimental tests using function generator for both coils are carried out to identify the parameters of the transfer function representing the introduced model. The measured signals for current and induced voltages are denoised for the parameter identification process. The denoised process is achieved using the MATLAB code ‘wdenoise’ while the parameters are estimated using the system identification toolbox. Verification of the proposed model is achieved using experimental results for the two coils. The sensitivity of the two coils is investigated based on the induced output voltage. The application concerning the two coils for monitoring the discharge current of the surge arrester is done. The results confirm the accuracy of the introduced RC model, as well as the performance of the cylindrical shape, is better than the traditional one. The simulation is carried out using MATLAB and ATPDraw programs.

Design and Performance Analysis of a Dynamo-Type HTS Flux Pump for a 10 kW Superconducting Generator

This paper presented the design and performance analysis of a dynamo-type HTS flux pump for a 10 kW superconducting generator. The HTS field coil of a 10 kW superconducting generator was designed and fabricated. The induced DC current, output voltage, and dynamic resistance of the flux pump connected to the HTS field coil were estimated using electric circuit equations. They were tested at various rotational speeds and air gaps, and the test results were compared with the estimated results. The performance was confirmed by applying a flux pump to the 10 kW superconducting generator. As a result, as the rotational speed of the flux pump increased, the induced DC current of the flux pump connected to the HTS field coil increased proportionally. As the air gap of the flux pump increased, the induced DC current decreased. A sufficient current was induced in the field coil to produce a 10 kW output.

Self-biased magnetoelectric current sensor based on SrFe12O19/FeCuNbSiB/PZT composite

This paper presents a packaged current sensor based on a SrFe12O19/FeCuNbSiB/PZT self-biased magnetoelectric (ME) cantilever. The hard magnetic material of the SrFe12O19 ribbon with a large coercive field provides a huge internal magnetic field to bias the magnetostrictive FeCuNbSiB(Fe73.5Cu1Nb3Si13.5B9) layers, which can increase the magnetic moment reorientation of FeCuNbSiB layers. Consequently, by coupling the vortex magnetic field around a current-carrying cable, the proposed SrFe12O19/FeCuNbSiB/PZT sensor has a large output voltage and electric current sensitivity without additional DC bias magnetic field. Experimental results demonstrate that the presented sensor has a higher sensitivity of 198.91 mV/A at 50 Hz and the induced output voltage shows a good linear relationship to the applied 50 Hz current. Also, the SrFe12O19/FeCuNbSiB/PZT sensor can distinguish small step changes of ˜0.01 A current. These results provide a significant advancement toward promising application of the trilayer self-biased ME laminate for power-line electric monitoring.

Self-driven photodetection based on impedance matching effect between a triboelectric nanogenerator and a MoS2 nanosheets photodetector

Constructing electronic systems without an external power source is urgently required toward self-powered photodetection. In this work, we proposed a self-driven photodetection system with a MoS2 nanosheets photodetector as light intensity sensor, a vertical contact-separate mode triboelectric nanogenerator (CS-TENG) as power source, and several LEDs as alarm. The MoS2 based planar photodetector was fabricated by conventional photolithography technique and lift-off process. It is highly sensitive for visible light illumination with high current on-off ratio and excellent reproducibility characteristics under light on-off switching. When conjuncting these functional devices, the induced output voltage of the CS-TENG is tuned by the load resistance of the photodetector, which is responded to the light intensity. The mechanism can be ascribed to the impedance matching effect between specific output characteristics of TENG and working status of photodetector. By adding a Zener diode acts as a voltage regulator, the self-driven renders the voltage and current varying from 1.58 to 20.60 V and 0.06–4.78 μA in a range of light intensity from 0 to 3.19 W/m2, respectively. Finally, it is demonstrated that the output of CS-TENG varies with the variable working states of the MoS2 photodetector and then accurately reflects on the lighted number of LEDs.

Improved magnetic sensor using laminated magnetic multilayer with coupled exciting and sensing micro planar coils

To improve the magnetic field sensitivity of giant magnetoimpedance (GMI) sensor at the low frequency, the authors reported a laminated magnetic multilayer with coupled exciting and sensing planar coils (i.e., FCseCexCseFCseCexCseF), which consists of two serially connected sandwich structures (i.e., FeNiCoSiB/sensing planar coil + exciting planar coil + sensing planar coil/FeNiCoSiB). Different from the previous FCexFCexF (i.e., FeNiCoSiB/exciting planar coil/FeNiCoSiB/exciting planar coil/FeNiCoSiB) multilayer and FCexF (i.e., FeNiCoSiB/exciting planar coil/FeNiCoSiB) sandwich laminates with only exciting coils, the investigated magnetic sensor uses the strong electromagnetic coupling between sensing coil and exciting coil, and the mutual inductance induced output voltage gets rid of the small resistance variation effect (caused by weak skin effect) at low frequency and also increases the ratio of additional inductance contributed by the magnetic ribbons to that by naked coils. The investigated magnetic sensor provides the magnetic field sensitivity of 188.6 mV/Oe at 1 MHz frequency, which is about 2.97 and 4.50 times as high as that for FCexFCexF and FCexF laminates, respectively. The investigated prototype also shows magnetic noise of 82.2 pT/Hz, which is 15% and 19% of noises for the FCexFCexF and conventional FCexF laminates at 1 MHz, respectively.

Impedance Matching Effect between a Triboelectric Nanogenerator and a Piezoresistive Pressure Sensor Induced Self‐Powered Weighing

AbstractHow to develop a simple and stable self‐powered force/pressure monitoring system has attracted extensive interests, yet it still faces intractable problems and challenges. As a mechanical force‐driven generator, the most straightforward application for triboelectric nanogenerator (TENG)‐based sensor is to directly monitor the external pressure. In this work, a self‐powered pressure monitor system is proposed by the conjunction of triboelectric and piezoresistive effects, in which a free‐standing disk‐shaped TENG (FD‐TENG) serves as an energy harvester, and a multiwalled carbon nanotube‐based flexible piezoresistive pressure sensor (PPS) works as a real‐time pressure monitor. The induced output voltage of the FD‐TENG is tuned by the working states of the PPS, which is responded to the external weight stimuli. Based on the impedance match between FD‐TENG and PPS, the self‐powered weighing system renders a voltage varying from 46.2 to 168.6 V in a range from 1 to 20 kg with a fast response/recovery kinetics (1.2 and 2.3 s) and good stability, which enable to directly reflect on the on/off status of appropriate amount LEDs powered by FD‐TENG. Finally, it is demonstrated to equip into a successive pedrail transportation system for monitoring the qualified/unqualified weight products.

Modelling and performance evaluation of energy harvesting linear magnetorheological (MR) damper

In this study, an magnetorheological (MR) damper has been designed based on its energy harvesting capability which combines the key benefits of energy generation (reusing lost energy) and magnetorheological damping (controllable damping force). The energy harvesting part has a magnet and coil arrangement to generate energy. A two-dimensional axisymmetric model of the proposed magnetorheological damper is developed in COMSOL Multiphysics where different magnetic field properties are analysed generally by finite element method. Finally, the energy harvesting capability of the proposed magnetorheological damper model is tested by a universal testing machine and observed through an oscilloscope. The maximum induced output voltage was around 0.7 V.

The output characteristic of cantilever-like tactile sensor based on the inverse magnetostrictive effect

The output characteristic model of a magnetostrictive cantilever-like tactile sensor has been founded based on the inverse-magnetostrictive effect, the flexure mode, and the Jiles-Atherton model. The magnetostrictive sensor has been designed and an output voltage is analyzed under the conditions of bias magnetic field, contact pressure and deflection of cantilever beam. The experiment has been performed to determine the relation among the induced output voltage, bias magnetic field, and pressure. It is found that the peak of the induced output voltage increases with an increasing pressure under the bias magnetic field of 4.8kA/m. The experimental result agrees well with the theoretical one and it means that the model can describe the relation among the induced output voltage, bias magnetic field, and pressure. The sensor with a Galfenol sheet may hold potentials in sample characterization and deformation predication in artificial intelligence area.

AC actuation contribution to the induced electromotive force in the miniaturized inductive planar microphone

In this paper, we aim to analyze the gain ratio in the output induced voltage of a CMOS-compatible miniaturized electrodynamic microphone which is based on the use of two coplanar concentric inductors. These latter are comparable to a concentric transformer with a secondary situated on the microphone diaphragm top. The study has been applied when the outer inductor is actuated using an AC bias instead of DC leading to a time-variable B-field. The induced output voltage expression has been evaluated using two distinct analytic methods: the magnetic field derivation and the electric field approach. When an AC current with frequency above that of the acoustic band is used to bias the primary, results show that the induced voltage increases and becomes independent from the incident pressure wave frequency. The paper demonstrates also that with an AC bias, the microphone induced voltage values can reach the order of hundreds of µVs, as opposed to only few µVs when applying a DC bias. The gain in the induced voltage has been investigated and it is shown that it can be correlated to the AC current frequency, ?c, and the inner inductor fluctuation frequency, ?p. Moreover, this has been quantified analytically and it is shown that it equals ?c/8?p. This result will not only enhance the overall performance of the microphone, but will also make the preamplification design less complicated by increasing the SNR ratio.

Optimization of Induced Voltage From CMOS-Compatible MEMS Electrodynamic Microphone With Coaxial Planar Inductances

This paper presents an improved design of the electrodynamic CMOS-MEMS microphone. The studied microphone is based on two integrated concentric planar inductors, a fixed outer one and an inner one attached on a flexible vibrating diaphragm. First, the magnetic field, generated by the outer inductor, was evaluated. Unlike conventional electrodynamic microphones based on Faraday’s law, the induced voltage was found to be proportional to the product of the diaphragm displacement and its velocity. Even though the induced output voltage is in the range of a few microvolts, and its frequency is doubled compared to that of the incident acoustic wave. This result pushed us to adjust and improve the basic principle of this kind of microphone by trying to generate a vertical downward shift of the microphone diaphragm while maintaining the COMS compatibility. The Lorentz force appears to be a possible alternative to the wafer bonding, as it will be automatically generated when we bias the inner inductor by a dc current. First, this paper shows that the induced voltage will be linear for a vertical fluctuation magnitude lower than $10~\mu \text{m}$ with an induced voltage in the range of several microvolts. Using the developed vertical offset technique, we show that induced voltages can be increased by a factor of 10 and the dynamic response of the electrodynamic microsensor will be appropriate for a use as a microphone.

The Output Characteristics of Galfenol Magnetostrictive Displacement Sensor Under the Helical Magnetic Field and Stress

This paper analyzes the output characteristics of a Galfenol magnetostrictive displacement sensor based on the Wiedemann effect, the Jiles-Atherton model, and the piezomagnetic effect. The sensor which is subjected to simultaneously circumferential excitation magnetic field, bias magnetic field, and stress will induce an output voltage. Experiments were performed to describe the induced output voltage versus the applied magnetic fields and stress with an Fe83Ga17 alloy wire as a function of the circumferential excitation magnetic field from 0.5 to 6 kA/m, the bias magnetic field of 3.5 kA/m, and the stress from 5 to 110 MPa. The induced output voltage increases with an increasing magnetic field and decreases with increasing stress. The experimental results agree well with the model calculations. The sensor with a Galfenol alloy wire can be used in displacement control and interface measurement.

Finite Element Analysis on Multi Parameter Characteristics of Inductive Lubricating Oil Wear Debris Sensor

Large wear debris is an important indication of abnormal wear of aviation engines. Analysis of the relationship between particle parameters and the output signal plays an important role to improve the sensor sensitivity. A three-coil simulating sensor model is constructed using APDL finite element program. After analyzing the influence factors to the induced output voltage of the sensor, such as debris material, location, size, exciting current etc, the fitting characteristic curves are obtained, realizing the quantitative analysis. Simulation results show that the sensor model can effectively distinguish between conductive and non conductive, ferromagnetic and non ferromagnetic debris. The induced voltage can reach 10-4 V for the 500 microns ferromagnetic abrasive particles. The characteristic curves provide important basis for further research on sensor structure optimization.

Waveform Distortion of Discharge Rising Currents caused by Built-in Inductor for Contact Discharges of Electrostatic Discharge Generators

To investigate the effects of built-in inductors on current rising waveform for contact discharges of electrostatic discharge generators (ESD guns), we simultaneously measured discharge currents and the resultant magnetic near-fields, and compared their results with those for an ESD gun with a metal cylinder in lieu of the inductor. As a result, we found that the magnetic near-field waveform is deformed by the distortion of the current rising waveform for an ESD gun with an inductor, while the ESD gun with a metal cylinder produces no distortion for the current rising waveform despite its rise time (400 ps) shorter than the International Electrotechnical Commission (IEC) specification so that there is no distortion for the corresponding magnetic near-field waveform. Using the Heidler's formula for typical discharge current waveform specified in the IEC, we calculated current rising waveform and the resultant induced output voltage of a magnetic probe, which shows that these results do not agree with those for the built-in inductor, while there is good agreement for the metal cylinder. This finding implies that immunity test results can be affected by the frequency characteristics of a built-in inductor inside an ESD gun, and thus that not only rise time but also current rising waveform of discharge currents should be specified for ESD immunity testing.

Frequency domain analysis of tesla transformer as a coupled second order system

This paper presents the frequency domain analysis of a Tesla transformer system to obtain relationship between the frequency of an input square wave and the induced output voltage. This system has two coils coupled to each other via air. Resistances, inductances and parasitic capacitances make the coils a coupled second order dynamical system when the primary is fed by a square wave. Mathematical analysis bases on the transfer function written in frequency domain. The solution aims to determine the frequencies in which the Tesla Transformer generates high output voltage. A comparison between the calculated and measured results shows the validity of the proposed approach.

셀룰로오스 Electro-Active Paper(EAPap)를 이용한 변형률 센서

Cellulose based electro-active paper(EAPap) is considered as a new smart material which has a potential to be used for biomimetic actuators and sensors. Beside of the natural abundance, cellulose EAPap is fascinating with its biodegradability, lightweight, high mechanical strength and low actuation voltage. When the external stress is applied to EAPap, it can generate the electrical output due to its piezoelectric property. Using piezoelectric behavior of EAPap, we studied the feasibility of EAPap as mechanical strain sensor applications and compared to commercial strain sensor. By measuring the induced output voltage from the thin piezoelectric cellulose EAPap under static and dynamic force, we propose cellulose EAPap film as a potential strain sensor material.

Characterization and sensor application of cellulose electro-active paper (EAPap)

As a novel piezoelectric material, the mechanical and piezoelectric properties of cellulose electro-active paper (EAPap) were studied. Young’s modulus of piezoelectric EAPap was dependant on the material orientation as compared with other EAP materials. The highest Young’s modulus was obtained at 0° direction, while the highest direct piezoelectric charge constant was achieved at 45°. By measuring the induced output voltage from the thin piezoelectric cellulose film under the applied impact force, we demonstrate that piezoelectric EAPap film has a potential for sensor applications.

Vortex magnetic field sensor based on ring-type magnetoelectric laminate

It has been found that ring-type magnetoelectric laminate composites of circumferentially magnetized magnetostrictive TERFENOL-D and a circumferentially poled piezoelectric Pb(Zr,Ti)O3 have high sensitivity to a vortex magnetic field. At room temperature, an induced output voltage from this ring laminate exhibited a near-linear response to an alternating current (ac) vortex magnetic field Hac over a wide magnetic field range of 10−9<Hac<10−3T at frequencies between sub-Hz and kHz.

Mechanism of the magnetic effect occurrence of YBaCuO superconductor

We report fabrication of a superconducting magnetometer of Wheatstone bridge type, consisting of a superconductor in liquid N 2 bath and two variable resistors, a null detector. Superconducting sensor was field cooled in the magnetic field of a 0.15 T permanent magnet by placing it near the N or S pole respectively, and it was assumed that both superconducting sensors had the same magnitude of trapped magnetic field with opposite polarity. The two variable resistors were used to balance the bridge circuit. Passing a current along the superconductor and applying a transverse magnetic field to it, a voltage is developed between the ends of the superconductors and varies as the current varies. The magnetic field dependence of the induced output voltage of the HTS magnetometer has been tested in the 10 −5 to 10 −4 T range by changing the distance between the pole of the permanent magnet to the S pole of the superconducting sensor, in this case the positive voltage increased, whereas the S pole of the magnet approached the N pole of the sensor.

Study of eddy current power loss from outer-winding coils of a magnetic position sensor

The present analysis is concerned with eddy current power loss of a magnetic position sensor, which arises from a non-uniform flux linkage distribution between magnetic material and position sensor. In the paper, a magnetic position sensor system is simplified to be an outer-winding coil along the axial direction of a low carbon steel bar, and developed a numerical model to compute the electrical characteristics by an excited current source. According to the simulated and measured data in this proposed model from 2.52 to 11.37 Oes, eddy current power losses of conducting material have a variation of 6.1% and 9.77%, respectively. Finally, the phases of waveform of the induced output voltage will also be obtained in the conducting material, and have a variation of 3.68% obtained by using the current source in the proposed model.

Application of amorphous ribbon as a stress sensor

Magnetization changes due to tensile stress for a Co-based amorphous ribbon sample with a negative magnetostriction constant were detected as the induced output voltage. The induced output voltage is proportional to the product of the magnitude of tension, frequency of the stress cycle, number of turns, cross section of the sample, and the value of the derivative of magnetization with respect to the tension. Each of these has been measured, and the possibility of using the sample as a stress sensor is discussed.