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1894 results about "Eddy current" patented technology

Eddy currents (also called Foucault's currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field. They can be induced within nearby stationary conductors by a time-varying magnetic field created by an AC electromagnet or transformer, for example, or by relative motion between a magnet and a nearby conductor. The magnitude of the current in a given loop is proportional to the strength of the magnetic field, the area of the loop, and the rate of change of flux, and inversely proportional to the resistivity of the material. When graphed, these circular currents within a piece of metal look vaguely like eddies or whirlpools in a liquid.

Mining high-voltage frequency converter fault analysis and diagnosis method and system

The invention relates to the technical field of fault diagnosis of power electronic equipment, and particularly discloses a fault analysis and diagnosis method and system for a mining high-voltage frequency converter, and the method comprises the steps: collecting the skin effect depth and parasitic parameter drift distance in real time under a high-frequency working condition through a multi-physics field sensor array; constructing three-dimensional current density distribution of the conductor based on a non-Euclidean space mesh generation technology, and dynamically correcting the equivalent resistivity of the conductor in combination with a metamaterial database to calculate a dynamic eddy current loss characteristic value; optimizing and solving the parasitic parameter time-varying evolution equation by using a quantum annealing algorithm to obtain a voltage peak sensitivity characteristic value; inputting the characteristic value into a pre-trained deep residual shrinkage network diagnosis model for multi-modal fusion analysis, and outputting a fault risk assessment result; according to the method, the problem of parasitic parameter time-varying characteristic modeling in the vibration environment is innovatively solved, and early warning of hidden faults is achieved.
Owner:JINING MINING GRP HAINA TECH ELECTROMECHANICAL CO

Electromagnetic relay control system

The invention relates to the technical field of electromagnetic relay control, in particular to an electromagnetic relay control system, which comprises a relay execution unit, a contact state monitoring unit and an intelligent viscosity elimination control unit, and is characterized in that the contact state monitoring unit acquires quantum tunneling effect impedance spectroscopy and acoustic emission energy entropy change signals in real time; the intelligent viscosity-eliminating control unit analyzes signals through a fusion welding risk multi-dimensional evaluator, triggers a three-stage control sequence, firstly starts a magnetostriction high-frequency oscillator to inject an inverted eddy current array, activates a hysteresis loop restorer to apply a gradient demagnetization potential field if the fusion welding risk multi-dimensional evaluator is not recovered, and finally, recovers the fusion welding risk multi-dimensional evaluator; when an acoustic emission signal is abnormal, a chaotic encryption message is generated through the fault feature topology generator and is linked with the magnetic solitary wave breaking device, ultrasonic frequency mechanical energy can be captured and converted into regenerative current, an adhesion evolution path is reconstructed after diagnosis, the problems of contact adhesion risk identification lagging and lack of multi-physics field cooperative control in the prior art are solved, and the reliability of the contact adhesion risk identification is improved. And the adhesion early warning success rate and the removal efficiency are improved.
Owner:SUZHOU JINBOYUAN ELECTRIC APPLIANCE CO LTD

Body armor composite interlayer defect positioning method and system based on multi-mode nondestructive testing, electronic equipment and storage medium

The invention provides a body armor composite interlayer defect positioning method and system based on multi-modal nondestructive testing, electronic equipment and a storage medium, and relates to the technical field of nondestructive testing. Ultrasonic guided wave, pulsed eddy current and infrared thermal wave excitation signals are synchronously applied to a body armor composite interlayer, and multi-modal response signals of all positions are collected; and generating an original multi-modal response signal set. And inputting the signal into a pre-trained deep convolutional neural network, determining a target frequency band parameter and a target noise suppression parameter of each modal response signal, and outputting an adaptive modulation parameter group. Performing frequency domain filtering and noise suppression processing on an original signal set to generate an optimized signal set, inputting spatial frequency features into a cross-modal feature fusion model, adaptively associating defect sensitive features of different modals through an attention mechanism in the model, and generating a three-dimensional defect distribution diagram of the composite interlayer, thereby realizing millimeter-level precision defect positioning. The precision and efficiency of body armor composite interlayer defect positioning can be improved.
Owner:BEIJING PEOPLE'S POLICE COLLEGE +1

Intelligent eddy current nondestructive testing method and system based on flexible GMR sensor array

The invention provides an intelligent eddy current nondestructive testing method and system based on a flexible GMR sensor array, and relates to the technical field of nondestructive testing. According to the invention, a GMR sensor array and a micro excitation coil array are integrated on a flexible substrate, and synchronous acquisition under multi-frequency and multi-phase excitation is realized by establishing a probe-workpiece unified space coordinate system and a time synchronization reference; performing temperature drift compensation, attitude correction and gap normalization processing on the original response tensor to generate a corrected response tensor; the intelligent inversion model based on the prior constraint of the electromagnetic field jointly identifies the conductivity, the thickness and the crack parameters, and outputs a defect parameter map and a confidence map; and a detection report containing the position, the size, the depth and the confidence coefficient is generated through spatial clustering and connectivity analysis, so that high-sensitivity and high-reliability nondestructive detection under a complex curved surface structure is realized.
Owner:INST OF SENSOR TECH GANSU ACAD OF SCI

Method and system for detecting pulsed eddy current of thermal power pipeline with coating layer

The invention discloses a pulsed eddy current detection method and system for a thermal power pipeline with a coating layer, and relates to the technical field of pulsed eddy current nondestructive detection.The pulsed eddy current detection method comprises the steps that pulsed eddy current detection simulation and experiment are conducted under the condition of a three-dimensional simulation model and a test piece, and excitation current waveform, amplitude and frequency parameters are determined; an induced voltage signal is collected, peak values, time points and attenuation characteristics are extracted, the corresponding relation between the wall thickness, the coating layer thickness and the welding seam structure and detection signals is constructed, a parameterized database is constructed, and temperature correction is completed; and optimizing a sensor structure and a signal acquisition scheme according to a parameterized database, obtaining detection data in a pipeline operation state, completing two-dimensional imaging of wall thickness distribution and welding seam positioning, and forming detection information covering a straight pipe, an elbow and a welding seam area. According to the method, wall thickness detection and welding seam positioning of the thermal power pipeline under the conditions of a thick wall and a thick coating layer are achieved through the full-process design of test piece modeling, simulation experiment and imaging collection.
Owner:GD POWER JIUQUAN GENERATION CO LTD

Pulse eddy current signal late period slope feature extraction method and system based on segmentation fitting

The invention discloses a pulse eddy current signal late period slope feature extraction method and system based on segmentation fitting, and belongs to the technical field of nondestructive testing. The method comprises the following steps: performing logarithmic transformation and filtering processing on a to-be-detected eddy current signal; intercepting a characteristic signal segment based on the filtering signal; dividing the feature signal segment into a plurality of sub-segments, performing piecewise linear fitting, determining a linear segment, and extracting a slope as a feature value; repeating the steps to obtain characteristic values of the test pieces with different thicknesses, performing curve fitting according to the characteristic values of the test pieces with different thicknesses and the corresponding thicknesses, and calculating a fitting error; and finally, iteratively optimizing the division number of the sub-segments by taking the minimum fitting error as a target. Through adaptive filtering, segmentation fitting and an intelligent optimization algorithm, the anti-interference performance, the linearity and the measurement precision of pulse eddy current signal feature extraction are remarkably improved, and efficient and reliable thickness detection of the high-temperature and high-pressure industrial pipeline under the condition that a heat preservation layer does not need to be disassembled is achieved.
Owner:CHINA UNIV OF PETROLEUM (EAST CHINA)

Double cold rolled non-oriented electrical steel and a method of manufacturing non-oriented electrical steel thereof

A double cold rolled non-oriented electrical steel sheet having a composition including: 0.0001%≤Carbon≤0.007%, 0.1%≤Manganese≤0.2%, 3.1%≤Silicon≤3.6%, 0.8%≤Aluminum≤1.1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition being iron and unavoidable impurities caused by processing, the microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, is from 35% to 45% when calculated in accordance of Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.64 T to 1.66 T.
Owner:ARCELORMITTAL SA

Double cold rolled non-oriented electrical steel and a method of manufacturing non-oriented electrical steel thereof

A double cold rolled non-oriented electrical steel sheet having a composition including, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.3%, 3.2%≤Silicon≤3.8%, 0.8%≤Aluminum≤1.1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition being iron and unavoidable impurities caused by processing, the microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 30% when calculated in accordance of Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.66 T to 1.69 T.
Owner:ARCELORMITTAL SA

Non-oriented electrical steel and a method of manufacturing non-oriented electrical steel thereof

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%,, 0.15% ≤Manganese≤0.2%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn ≤5.5%, and can contain various optional elements, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, of 35 to 55% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.635T to 1.670T.
Owner:ARCELORMITTAL SA

Double cold rolled non-oriented electrical steel and a method of manufacturing non-oriented electrical steel thereof

A double cold rolled non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.1%≤Manganese≤0.3%, 3.1%≤Silicon≤3.8%, 0.6%≤Aluminum≤0.8%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition is iron and unavoidable impurities caused by processing. The microstructure ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, of 40 to 50% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.66T to 1.7T.
Owner:ARCELORMITTAL SA

Method and system for measuring plasma current in quasi-ring symmetric star simulator

The invention provides a method and a system for measuring plasma current in a quasi-ring symmetrical star simulator, and relates to the technical field of star simulators, and the method comprises the steps: determining a sensor design index according to a bootstrap current simulation calculation result, and converting the design index into an actual arrangement scheme according to an installation environment constraint; all the magnet coils are independently excited in a plasma-free state, wall eddy current interference signals generated by the magnet coils are calibrated, and thus wall eddy current calibration voltage signals are output; a sensor in an actual arrangement scheme is used for synchronously collecting a total original induced voltage signal including plasma current and wall eddy current; an integral voltage signal representing the total current is output; and compensating the integral voltage signal by using the wall eddy current calibration voltage signal, and inverting the final measurement value of the plasma current in the quasi-ring symmetric star simulator. The device and the method have the beneficial effects that the interference of a stray field on a measurement result is weakened, and a high-precision diagnostic tool is provided for the plasma physical research of the star simulator.
Owner:SOUTHWEST JIAOTONG UNIV

Copper rod grain size detection method and system based on double-frequency eddy current analysis

The invention relates to the technical field of copper rod detection, in particular to a copper rod grain size detection method and system based on double-frequency eddy current analysis, and the method comprises the steps: synchronously obtaining a high-frequency eddy current response signal and a low-frequency eddy current response signal of the surface of a moving copper rod according to an orthogonally arranged double-frequency eddy current probe, and collecting the moving speed of the copper rod in real time; performing phase demodulation on the high-frequency eddy current response signal and the low-frequency eddy current response signal to respectively obtain a first phase angle and a second phase angle; calculating an instantaneous difference value between the first phase angle and the second phase angle, and generating an original phase difference characteristic quantity; performing dynamic compensation on the original phase difference characteristic quantity based on the movement speed of the copper rod to generate a speed compensation phase difference characteristic quantity; and inputting the speed compensation phase difference characteristic quantity into a pre-calibrated grain size mapping relation model to obtain a real-time grain size grade value. According to the invention, eddy current response interference caused by speed change in the continuous movement process of the copper rod is effectively eliminated, and high-precision detection of the grain size grade is realized.
Owner:CHANGZHOU TONGTAI HIGH CONDUCTIVITY NEW MATERIALS CO LTD

Metal flat plate thickness and conductivity eddy current measurement method and system

The invention discloses a metal flat plate thickness and conductivity eddy current measurement method and system. According to the method, an electromagnetic detection platform is built, and a coaxial excitation-receiving eddy current probe structure is designed. Establishing a coaxial eddy current detection analysis model, and deducing a dynamic calculation result of mutual inductance parameters of the sensor in a frequency sweeping mode; setting two PID (Proportion Integration Differentiation) controllers and initial control variables thereof, and inputting the control variables serving as a thickness value and a conductivity value into the analytical theoretical model to obtain a corresponding mutual inductance change result; calculating an instantaneous error term and an accumulative error term of the current iteration period in real time, and when the error exceeds a preset convergence threshold value, inputting the error into a PID controller and updating the two control quantities until the maximum iteration frequency is reached; otherwise, outputting a control variable value, wherein the two control variables output by the controller are the thickness and the conductivity of the metal plate respectively. According to the invention, the thickness and conductivity of the metal plate can be accurately and simultaneously measured.
Owner:TSINGHUA UNIVERSITY

Non-oriented electrical steel and a method of manufacturing non-oriented electrical steel thereof

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.25%, 3.2%≤Silicon≤3.8%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and various optional elements. The remainder composition is iron and unavoidable impurities caused by processing. The microstructure is ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 33% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.630T to 1.65T.
Owner:ARCELORMITTAL SA

Eddy current displacement sensor and temperature drift compensation method

The embodiment of the invention provides an eddy current displacement sensor and a temperature drift compensation method. The eddy current displacement sensor comprises a probe, a cable and a front-end device, the probe comprises a metal probe protection cover, and a measuring coil, a metal partition plate, a compensating coil, a metal pressing sheet and a framework body which are arranged in the metal probe protection cover, and the measuring coil, the metal partition plate, the compensating coil and the metal pressing sheet are sequentially arranged on the framework body; the first end of the compensating coil and the first end of the measuring coil are both connected with the front-end device, and the front-end device is used for carrying out differential processing on a measuring signal sensed by the measuring coil and a compensating signal sensed by the compensating coil to obtain distance information. The sensor provided by the embodiment of the invention can provide high-precision displacement measurement in a complex environment, is suitable for various industrial application scenes, especially in an environment with high temperature or large temperature fluctuation, and ensures the reliability and accuracy of a measurement result.
Owner:JIANGSU LIHE I & C TECH CO LTD

Accurate positioning method of automatic transmission conductor breaking device

The invention discloses a precise positioning method of an automatic transmission conductor breaking device, and relates to the technical field of line detection, and the method comprises the following steps: obtaining eddy current detection signal data of the surface of a transmission conductor; performing sliding window segmentation processing on the eddy current detection signal data, and extracting a transient impedance sequence; the transient impedance sequence is processed through a phase sensitive demodulation circuit, and impedance real part information and impedance imaginary part information are separated; impedance real part information features are extracted, impedance imaginary part information frequency domain energy is deconstructed, and an impedance track feature vector is generated; and carrying out space segmentation on the impedance track feature vector, and calculating defect position information and severity level based on the offset of the track center point. The problem that an existing wire detection technology is insufficient in automation level and difficult to meet the requirement for accurate defect positioning of an automatic wire breaking device is solved.
Owner:CHIZHOU POWER SUPPLY COMPANY STATE GRID ANHUI ELECTRIC POWER

Non-oriented electrical steel and a method of manufacturing non-oriented electrical steel thereof

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.21%≤Manganese≤0.7%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and can contain various optional elements. The remainder composition being composed of iron and unavoidable impurities. The microstructure is ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 35% to 45% and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.63T to 1.66T.
Owner:ARCELORMITTAL SA

Conductor ring and magnetic resistance array combined type permanent magnet thrust bearing and damping force calculation method

The invention belongs to the technical field of mechanical transmission, and discloses a conductor ring and magnetic resistance array composite permanent magnet thrust bearing and a damping force calculation method. The conductor ring and magnetic resistance array combined type permanent magnet thrust bearing realizes the bearing of non-contact magnetic thrust through the combination of the eddy current ring and the magnetic group array. When thrust from a propeller at the stern end of a propulsion shafting acts, the rotor magnetic group array axially moves, axial traction force is generated between the rotor magnetic group array and the stator magnetic resistance array to counteract the thrust action from the axial direction, meanwhile, the magnetic group array cuts the vortex ring, induction damping is generated on the surface of the vortex ring, damping force is formed, and the vortex ring is driven to rotate. And therefore, the longitudinal vibration during transmission of the propulsion shafting is reduced, and the propulsion shafting system is more silent and stable during operation. In addition, the damping force calculation method does not need complex three-dimensional structure modeling and grid division, is simple in solution, high in universality and short in calculation time consumption, and has high engineering application practical value.
Owner:DALIAN UNIV OF TECH

Coating layer wall thickness pulsed eddy current detection method and system based on multiple eddy current rings

The embodiment of the invention provides a coating layer wall thickness pulse eddy current detection method and system based on multiple eddy current rings, and the method comprises the steps: applying a square wave excitation signal to an excitation coil, and carrying out the induction in a structural member with a coating layer to generate eddy current; collecting a voltage signal generated by induction of an attenuation magnetic field generated by the eddy current by using a receiving coil, wherein the attenuation process of the voltage signal comprises three stages; identifying a power function interval of the second stage to determine the starting time of the third stage; taking the starting time of the third stage as a reference, and selecting a preset thickness quantitative time interval in the third stage; calculating a first-order derivative of the voltage signal to time under a single logarithmic coordinate system in the thickness quantitative time interval to obtain a slope; according to the quantitative relation between the slope and the wall thickness of the structural part with the coating layer, the wall thickness value of the structural part with the coating layer is obtained through calculation.
Owner:XIAN THERMAL POWER RES INST CO LTD +1

Eddy current heating device and heating method for thermoluminescence element

The invention relates to an eddy current heating device for a thermoluminescence element and a heating method. The device comprises a heating disc, a copper coil assembly, a supporting frame, a temperature measuring sensor assembly and a control circuit, the heating disc is in a disc shape, and the copper coil assembly is composed of four multi-layer closely-wound fan-shaped copper coils which are arranged in four quadrant areas of the heating disc respectively; the temperature measuring sensor assembly is provided with four temperature sensors which are embedded into the bottom of the heating disc through heat-conducting glue and connected with the control circuit. The control circuit adopts a PID (Proportion Integration Differentiation) algorithm to independently adjust the current of each sector according to feedback signals of each temperature sensor, realizes rapid temperature rise and accurate temperature control through frequency adjustment and power compensation, and has an over-temperature protection function. According to the device, the temperature of the heating disc can be raised to 300 DEG C within 3 seconds, and the temperature deviation is controlled within + / -0.5 DEG C. Compared with traditional resistance heating, the device has the advantages of being fast in temperature rise, low in energy consumption, high in temperature uniformity, convenient to maintain and the like, and meets the high-precision temperature control requirement of thermoluminescence measuring and reading equipment.
Owner:CHINA INST FOR RADIATION PROTECTION

Valve equipment and semiconductor device processing equipment

The utility model discloses a valve device and a semiconductor device processing device. The valve apparatus includes: a valve body including an external coil therein; the valve plate is movably arranged in the valve body, and the opening degree of the valve equipment is adjusted by adjusting the pose of the valve plate; and an internal coil provided inside the valve plate, the internal coil generating an eddy current through an alternating magnetic field generated in the valve body by an alternating voltage applied to the external coil to inductively heat the valve plate. By means of the valve equipment, the surface of the valve plate can be directly heated, the temperature of the valve plate is increased, and therefore blockage of the valve plate caused by deposition of reaction by-products on the valve plate in the carbon mask deposition process is reduced.
Owner:PIOTECH (SHANGHAI) CO LTD

Transformer with small size and strong short-circuit current resistance

The invention relates to the technical field of transformers, and particularly discloses a small-size and strong-short-circuit-current-resistant transformer, which comprises a transformer body, the transformer body comprises an iron core, a plurality of iron cores, a plurality of short-circuit-current-resistant coils, a plurality of short-circuit-current-resistant coils and a plurality of short-circuit-current-resistant coils, the insulating cylinder is arranged on the outer side of the core column in a sleeving manner; the winding sleeves the outer side of the insulating cylinder, the winding comprises a circular coil wound on the outer wall of the insulating cylinder and a plurality of layers of elliptical coils wound on the outer side of the circular coil, and the trend of the elliptical coils is parallel to magnetic lines generated by the circular coil; heat dissipation channels parallel to the axis of the core column are formed between the circular coils and the oval coils and between every two adjacent oval coils. The space of the core column can be effectively utilized, the elliptical ring can fill the external space, the magnetic field trend of the outer elliptical coil is parallel to that of the inner circular coil, high-frequency loss caused by the proximity effect and eddy-current loss during short circuit can be effectively reduced, and the normal operation efficiency and short-circuit endurance capacity of the transformer are improved.
Owner:SICHUAN ZHIXIANG ELECTRIC APPLIANCE CO LTD

Aluminum pipe local conductivity regulation and control method, system and equipment based on dynamic electromagnetic field modulation and medium

The invention relates to an aluminum pipe local conduction regulation and control method, system and device based on dynamic electromagnetic field modulation and a medium, and the method comprises the steps: driving an electromagnetic coupling array to scan a target conduction region of an aluminum pipe, so as to construct a three-dimensional dynamic electromagnetic model; analyzing and generating a multi-band excitation parameter combination in a bandwidth constraint range according to the target conductivity gradient parameter; the method comprises the following steps: driving an electromagnetic coupling array by a multi-band excitation parameter combination, collecting an electromagnetic response spectrum of a target conductive area in real time, extracting an eddy current characteristic component set, calculating an obtained phase compensation amount, and dynamically adjusting an excitation phase difference and a power ratio of the electromagnetic coupling array to form a controllable standing wave interference field; and solving the Lyapunov function gradient difference between the node distribution characteristics of the standing wave interference field and the predicted value of the three-dimensional dynamic electromagnetic model so as to iteratively update the multi-band excitation parameter combination. According to the invention, high-precision dynamic regulation and control of the conductivity gradient of the aluminum tube are realized, the energy consumption is effectively reduced, and the stability of a standing wave interference field is enhanced.
Owner:CHANGSHA HENGJIA ALUMINUM CO LTD

Sine constant current source excitation method for eddy current displacement sensor

The invention discloses an eddy current displacement sensor sine constant current source excitation method, and belongs to the technical field of sensor measurement and control. The method comprises the following steps: S1, generating positive and negative symmetric reference voltages through a reference voltage source circuit; s2, outputting a square wave control signal with adjustable frequency by the control chip, and driving a switching circuit to generate a square wave taking the positive and negative reference voltage as a level; s3, processing the square wave through a filter circuit to obtain a standard sine wave voltage signal; and S4, converting the sine voltage signal into sine constant current source excitation through a Howland current source circuit, and outputting the sine constant current source excitation to a sensor probe coil. According to the invention, through combination of digital control and analog conversion, the circuit structure is simplified, the cost is significantly reduced, and convenient adjustment of the output frequency and high stability and precision of the output current are realized at the same time.
Owner:HUNAN AEROSPACE ELECTROMECHANICAL EQUIP & SPECIAL MATERIAL INST

Magnetofluid type silicon controlled rectifier radiator and heat dissipation control method thereof

The invention discloses a magnetofluid type silicon controlled rectifier radiator and a heat dissipation control method thereof. The radiator comprises a silicon controlled rectifier, a magnetic fluid chamber is attached to the outer side of the silicon controlled rectifier, the magnetic pole array is installed in the magnetic fluid chamber, and cooling fins are assembled outside the magnetic fluid chamber. When alternating current is introduced into the cavity where the magnetic fluid liquid chamber is located, the alternating current and the magnetic field interact to generate Lorentz force, the Lorentz force drives the magnetic fluid to form directional eddy current so as to achieve convective heat exchange on the silicon controlled rectifier, and heat absorbed by the magnetic fluid and air are subjected to heat exchange through the cooling fins. Junction temperature out-of-control caused by local hot spots of the silicon controlled rectifier can be solved, secondary damage of mechanical vibration of a heat dissipation system to welding spots is eliminated, and the highest junction temperature area of the silicon controlled rectifier is focused and cooled according to needs.
Owner:THREE GORGES JINSHAJIANG CHUANYUN HYDROPOWER DEV CO LTD

Inspection system for detecting surface cracks via eddy current thermography

An inspection system detects defects within a component using eddy current thermography. An infrared camera detects heat from a defect within the component generated by the eddy current interfering with the defect. The eddy current is generated in the component by a magnetic field applied to the component by an inductor assembly. The inductor assembly includes a magnetic core having magnetic core material and two arms, each arm including a coil to generate the magnetic field. The inductor assembly is configured to apply the magnetic field at an angle offset from a horizontal axis of the magnetic core such that the eddy current flows at an angle within the component relative to the offset angle. Further, the magnetic core material can be shaped to apply the magnetic field at the offset angle or to accommodate complex component shapes.
Owner:RTX CORP

Infrared pulse thermal radiation grinding burn nondestructive testing method and system

The invention provides an infrared pulse thermal radiation grinding burn nondestructive testing method and system, and belongs to the technical field of nondestructive testing. Comprising the following steps: inputting an excitation signal to an induction coil, and inducing a pulsed eddy current in a tested part for heating; a thermal infrared imager and a depth camera are used for obtaining a thermal response temperature matrix of a measured area of the part and a three-dimensional point cloud of the measured area; then, constructing a thermal response model of the part; extracting a time sequence temperature curve of the heating stage and the natural cooling stage of the detected area, and establishing a grinding burn discrimination function to judge whether a grinding burn area exists or not; and the thermal infrared imager and the depth camera are calibrated, the grinding burn area under the coordinate system of the thermal infrared imager is projected into the three-dimensional point cloud of the depth camera, the position of the grinding burn area under the world coordinate system is obtained, and detection and positioning of the grinding burn area are achieved.
Owner:WUHAN UNIV OF TECH

Interlayer gold purity evaluation method and device based on hybrid model, equipment and medium

The invention discloses an interlayer gold purity evaluation method and device based on a hybrid model, equipment and a medium. The method comprises the following steps: collecting original data; inputting the processed original data into a hybrid model for training to obtain a trained hybrid model; wherein the hybrid model comprises a feature extraction module, a weighted fusion unit and a classification module which are connected in sequence; collecting a second pulsed eddy current signal and a second supplementary feature corresponding to the gold to be detected; inputting the second pulse eddy current signal and the second supplementary feature into a trained hybrid model, and outputting a prediction vector; and converting the prediction vector into a one-hot code, and obtaining the number of the corresponding gold to be tested through the one-hot code. The problem that an existing classification mixing model cannot be suitable for a highly-adulterated gold purity detection scene is solved, the classification precision of adulterated gold purity detection is improved, and the application range of the classification mixing model in the field of scarce sample detection is widened.
Owner:CHANGSHA UNIVERSITY

Magnetically controlled reactor electromagnetic transient simulation method, device, equipment and medium

The invention provides a biphase composite magnetic material magnetically controlled reactor electromagnetic transient simulation method, device and equipment and a medium, and relates to the technical field of power equipment magnetic material testing and electromagnetic transient simulation. According to the invention, the test winding is arranged on the excitation winding of the magnetically controlled reactor, and multi-dimensional means of obtaining total iron loss through an open circuit test, obtaining magnetic hysteresis loss through a frequency reduction test, obtaining copper loss and leakage reactance through a short circuit test and the like are combined, so that separation of magnetic hysteresis loss, eddy current loss and additional loss can be realized; a high-fidelity hysteresis loop and a magnetic conductivity change rule are obtained, and the nonlinear characteristic and hysteresis response of the magnetic core can be accurately captured, so that the predictive capability of equipment performance and the sensing capability of an operation state are improved.
Owner:WUHAN UNIV +2

Hysteresis loop analysis method for transformer no-load loss test

The invention provides a hysteresis loop analysis method for a transformer no-load loss test, and belongs to the technical field of transformers. Exciting voltage and current signals are collected in a transformer no-load state, and an active filter is used for carrying out digital filtering processing to eliminate harmonic interference; a data corresponding relation between magnetic flux density and magnetic field intensity is established through a digital integration algorithm and a magnetic field intensity calculation formula to form original hysteresis data, the original hysteresis data is processed by using a hysteresis loop optimization model, a complete hysteresis loop curve is generated, and the hysteresis loop area is calculated. According to the hysteresis loop area, the hysteresis loss power density is calculated through the iron loss calculation function, the total value of the transformer no-load loss is obtained by combining the eddy current loss calculation result, and the technical problems that the hysteresis loop reconstruction precision is not high and the complex hysteresis phenomenon cannot be adapted in the transformer no-load loss test are solved.
Owner:YUNNAN JINHUA ELECTRIC POWER ENGINEERING CO LTD