1673 results about "Magneto resistance" patented technology

The invention provides an electrical equipment remote maintenance guidance method and system. The method comprises the following steps: capturing an aperiodic torque waveform and a magnetic field gradient abnormal signal by deploying a torque fluctuation sensor and a magnetoresistive sensor; performing multi-scale frequency band division on the non-periodic torque waveform, screening out a transient high-frequency component in a start-stop stage of equipment, and separating out a magnetic field polarity reversal characteristic from a magnetic field gradient abnormal signal; performing cross-domain matching on the occurrence time of the transient high-frequency component and the spatial orientation of the magnetic field polarity reversal feature to generate a mixed feature mark; calculating a frequency band overlapping degree based on the time-frequency energy distribution marked by the mixed features and generating a coherence map; and matching a fault historical case library according to the coherence map, and outputting a maintenance strategy set aiming at the rotating shaft dynamic unbalance and electromagnetic interference superposition fault. According to the invention, through fusion of torque fluctuation and magnetic field distortion collaborative analysis, the precision of mechanical and electromagnetic composite fault diagnosis of the rotating shaft is improved.

The invention discloses a three-degree-of-freedom permanent magnet biased magnetic bearing which comprises a rotor system, a radial magnetic bearing stator system and an axial magnetic bearing stator system. The rotor system comprises a rotor, a radial magnetizing permanent magnet ring and a magnetic conducting ring; the radial magnetic bearing stator system comprises a radial stator iron core, a magnetism isolating ring and a radial coil winding; the axial magnetic bearing stator system comprises a sheet-shaped arc-shaped radial magnetizing permanent magnet, an axial stator iron core and an axial coil winding; according to the three-degree-of-freedom permanent magnet biased magnetic bearing, the axial magnetic bearing stator surrounds the periphery of the rotor and is in the same plane with the radial magnetic bearing stator, so that the axial length of the magnetic bearing is reduced, and the structure is compact; radial two-degree-of-freedom translation control and axial translation control can be realized; magnetic isolation rings are additionally arranged among the radial stator iron cores, so that decoupling of a magnetic circuit controlled by two radial channels of an x axis and a y axis is realized; the two radial channels are biased by independent permanent magnets, so that the decoupling of a biased magnetic circuit is realized, and the influence of air gap magnetic resistance change is weakened; and the second air gap is arranged, so that the axial control magnetic circuit does not pass through the permanent magnet ring, and the power consumption of the magnetic bearing is further reduced.

The invention discloses a high-sensitivity detection method for the safety of a battery cell, and the method comprises the following steps: S1, collecting the data of the battery cell in real time through a tunnel magnetoresistive sensor, and outputting a preliminary detection data set; s2, generating a micro-short circuit risk identification signal based on the preliminary detection data set; s3, generating a temperature anomaly distribution map by using the preliminary detection data set; s4, generating a thermal runaway early warning signal based on the temperature anomaly distribution map; s5, performing magnetic field scanning on the pole piece to generate a magnetic distortion data atlas; s6, constructing battery cell multi-source detection data, inputting the data into the physical information neural network, and training to obtain a final battery cell aging evolution model; s7, outputting a charging and discharging strategy optimization instruction based on the final cell aging evolution model; and S8, uniformly fusing the micro short circuit risk identification signal, the thermal runaway early warning signal and the charging and discharging strategy optimization instruction to generate a comprehensive response control instruction. According to the method, magnetic resistance sensing and physical modeling are fused, and intelligent prediction and response control optimization of the risk of the battery cell are realized.

The invention provides a vertical axis wind turbine power prediction method based on multi-dimensional environment data, and relates to the technical field of vertical axis wind turbine power based on the multi-dimensional environment data. Multi-dimensional data are collected in real time based on a sensor network, and the multi-dimensional data comprise environment parameters such as wind speed, turbulence intensity and temperature and humidity, and operation states such as rotor rotating speed and pitch angle; secondly, performing empirical mode decomposition on a vibration acceleration signal, constructing a physical information neural network, taking environmental data and an aerodynamic load frequency domain energy spectrum as input, outputting a real-time wind energy utilization coefficient and an aerodynamic coefficient, and finally, determining the aerodynamic load based on an aerodynamic load time domain signal. A load cyclic spectrum is extracted by adopting online rain flow counting of dynamic window length, an accumulated damage value is calculated in combination with a fatigue damage model of humidity correction, and when the residual life is lower than a threshold value, load peak suppression and power generation efficiency balance are realized through cooperative control of magnetic resistance torque linear attenuation and flap fuzzy PID (Proportion Integration Differentiation).

The embodiment of the invention provides a magnetic field simulation method and device for magnetic steel in a signaling pointer and electronic equipment. The magnetic field simulation method comprises the steps that size parameters of the magnetic steel in the signaling pointer and position data of a magnetic resistance internal induction device corresponding to the signaling pointer relative to the magnetic steel are obtained; according to the size parameters, constructing a geometric model of the magnetic steel, and according to the position data, determining a running track of the induction device running around the magnetic steel by one circle; based on magnetic field simulation software, importing the geometric model and material attributes of the magnetic steel, establishing a three-dimensional coordinate system according to a preset rule, and determining magnetic field data of the magnetic steel based on the three-dimensional coordinate system; wherein the three-dimensional coordinate system takes the circle center of the moving track of the magnetic steel as a coordinate origin, the horizontal direction penetrating through the origin as an X axis, a straight line penetrating through the origin and perpendicular to the X axis as a Y axis, and a straight line penetrating through the origin and perpendicular to the X axis and the Y axis as a Z axis; and determining a magnetic field change curve corresponding to the moving trajectory according to the magnetic field distribution. According to the method, the simulation efficiency of the signaling pointer magnetic steel is improved.

The invention relates to the technical field of magnetic suspension conveying, in particular to an AI-based intelligent multi-rotor magnetic suspension conveying system which comprises an assembly rail base, six linear guide rails, two annular guide rails and a rotor trolley. Damping rings are embedded in the side walls of the two annular guide rails and the six linear guide rails at equal intervals; two opposite L-shaped supports are fixedly installed on the two sides of the bottom of the mover trolley, and adjustable guide magnets are movably installed on the side walls of the L-shaped supports. Through the action of the damping ring and the adjustable guide magnet, transverse vibration of the rotor trolley in the moving process can be remarkably restrained, and then the stability and the operation efficiency of the system are improved; the magnetoresistive sensor receives a magnetic field signal sent by the magnetic field sensor, the magnetic field signal is converted into position information through a decoding algorithm of the AI controller, the position and state information of each mover trolley is accurately detected, collaborative operation of the multiple mover trolleys is achieved, and it is ensured that the mover trolleys efficiently and stably operate according to a preset path and sequence.

The invention discloses a magnetic integrated transformer design method and device for a CLLC converter, relates to the technical field of high-frequency transformer design, and aims at solving the technical problem that an existing magnetic integrated transformer design method for the CLLC converter is poor in design precision. The method comprises the following steps: based on a preset transformer magnetic circuit model, a preset area product method and preset constraint conditions, determining the total number of turns of primary and secondary winding coils, the number of turns of the primary and secondary winding coils distributed to left and right side columns and the length of left and right side magnetic powder core magnetic columns, further obtaining the magnetic resistance of a magnetic flux branch, and considering the magnetic flux effect of an air gap edge. The accurate air gap length is determined, the magnetic resistance at the corner of the magnetic core and the extra leakage inductance value in air near a winding coil are fully considered, the primary side leakage inductance in a target magnetic core magnetic circuit, the total amount of the target air extra primary side leakage inductance and the magnetic powder core material magnetic conductivity of the target left and right side magnetic powder core magnetic columns are determined, and then a preset coil winding mode is combined. A magnetic integrated transformer for a CLLC converter is designed.

The invention provides a fault positioning method and system for an overhead line of a power distribution network, and a storage medium. The method comprises the steps of obtaining a plurality of fault traveling wave magnetic field signals; performing the following steps on any signal: performing phase-mode transformation on the signal, extracting and decomposing a line mode component, determining a modulus maximum point, and determining the time corresponding to the point as a first fault traveling wave head arrival moment; carrying out clock synchronization on the moment, and obtaining a wave head arrival moment of a second fault traveling wave; obtaining a to-be-detected fault point and a line parameter; based on the wave head arrival moments of the plurality of second fault traveling waves, extracting a head end arrival moment and a tail end arrival moment; and performing fault positioning on the overhead line of the power distribution network based on the head end arrival time, the tail end arrival time and the fault line parameters. According to the fault positioning method for the overhead line of the power distribution network, interference to normal operation of the power distribution network can be avoided, and high-precision non-intrusive positioning of the overhead line of the power distribution network is realized through the tunneling magnetoresistive sensor.

A magnetoresistive element of the present disclosure includes a multilayer structure made up of at least a fixed magnetization layer, an intermediate layer and a storage layer. A first side wall is formed on a side wall of the multilayer structure. A second side wall is formed on the first side wall. The first side wall is made of an insulating material, for instance SiN or AlOx, that prevents intrusion of hydrogen. The second side wall is made of a hydrogen storage material, for instance titanium.

A semiconductor device that includes a substrate, a crystalline bottom electrode layer on an upper side of the semiconductor substrate, a conductive crystalline metal layer above the crystalline bottom electrode layer, and a conductive oxide layer above the conductive crystalline metal layer. The conductive oxide layer has a low resistance. The semiconductor device also includes a magnetic tunnel junction (MTJ) above the conductive crystalline metal layer, the MTJ including a tunnel barrier layer, a free layer on a first side of the tunnel barrier layer and a reference layer on a second side of the tunnel barrier layer opposite the first side.

The invention provides a self-calibration method of a TMR (Tunnel Magnetoresistive) sensor and a TMR sensor array for current measurement, and relates to the technical field of quantum current sensors. According to the method, a double Wheatstone bridge structure is adopted, a to-be-measured bridge is used for measuring a to-be-measured magnetic field, and a reference bridge is used for measuring a known reference magnetic field; the self-calibration of the TMR sensor is realized by calculating the ratio of the output voltages of the two bridges, so that measurement errors caused by environmental factors such as temperature, humidity and mechanical vibration are eliminated; moreover, the invention provides a TMR sensor array for current measurement, the application of the TMR sensor array further enhances the adaptive capacity of the TMR sensor array in a complex environment, and the array is formed by a plurality of TMR sensor units, so that not only can the spatial resolution of measurement be improved, but also the fault-tolerant capability of the system can be improved through redundancy configuration, and the system reliability is improved. The array structure enables the TMR sensor to perform accurate measurement at a plurality of measurement points at the same time to obtain accurate measurement current.

The invention discloses an AMR magnetic resistance unit, an AMR magnetic resistance module, an angle sensor and a chip wherein the AMR magnetic resistance unit comprises: a first AMR magnetic resistance unit; the first AMR magnetic resistance unit comprises a plurality of first AMR magnetic resistance strips, the plurality of first AMR magnetic resistance strips surround a circle center and are distributed in the radial direction, and each first AMR magnetic resistance strip is of a 60-degree arc-shaped strip-shaped structure. According to the AMR magnetic resistance unit, the AMR magnetic resistance module, the angle sensor and the chip, harmonic waves, especially sixth harmonic waves, can be better eliminated, magnetic domain collective hysteresis and noise are reduced, and the anti-eccentricity capacity is improved.

The invention discloses a gadolinium boron molybdate magnetic refrigeration material with triangular magnetic resistance and a preparation method and application of the gadolinium boron molybdate magnetic refrigeration material. The chemical formula of the material is Gd2B2MoO9, the material belongs to a triclinic system, and the space group is P-1; the crystal structure has the characteristic that nearest rare earth Gd ions have magnetic resistance file; the material is prepared by a solid phase method or a sol-gel method; the magnetic phase change temperature of the material is 0.7-0.9 K, the material shows a remarkable magnetothermal effect at low temperature, the maximum isothermal magnetic entropy change values of the material are 30.0-35.0 J / kg.K and 51.0-55.0 J / kg.K respectively under the magnetic field change of 0-2T and 0-5T, and the material can be applied to low-temperature magnetic refrigeration. The gadolinium boron molybdate Gd2B2MoO9 material with triangular magnetoresistance provided by the invention has the advantages of low raw material price, simple process and lower equipment requirement, and is suitable for industrial production.

The invention discloses a low-power-consumption winch sensor based on a tunneling magnetoresistance effect. The low-power-consumption winch sensor comprises a measurement module, a signal conversion unit, a shell, a mandrel, a magnetic rotary disc and a detection assembly. The magnetic turntable and the mandrel are connected and rotate synchronously, the detection assembly comprises a TMR sensing element and N magnets, and the magnetic turntable is provided with mounting blind holes for embedding the magnets; the TMR sensing element is arranged on the shell and comprises a mounting plate and two sensing units, the magnetic domain directions of the two sensing units are perpendicular to the rotation axis, magnetic resistance signals of the two sensing units are converted through the signal conversion unit and input into the measuring module, the horizontal distance between the centers of the two sensing units and the magnet and the rotation axis is R, and the center distance L of the two sensing units is smaller than R * sin (180 degrees / N); the sensor is based on the TMR tunneling magnetoresistance effect, is high in detection sensitivity and low in energy consumption, outputs square wave signals with phase differences, can be used for a measurement module to accurately analyze and calculate the rotating speed and the rotating direction of a winch roller, is simple in overall structure, small in radial size and easy to install, and the installation precision is controlled.

The invention discloses a permanent magnet auxiliary synchronous reluctance motor magnetic barrier asymmetric rotor structure, which comprises magnetic barrier groups arranged on a rotor core along the axial direction of the rotor core, each stage of magnetic barrier group comprises three layers of radially arranged air magnetic barriers, and the air magnetic barriers are a third magnetic barrier, a second magnetic barrier and a first magnetic barrier in sequence from the center of a rotating shaft in the rotor core to a stator core; a first permanent magnet is embedded in the magnetic barrier bottom edge of the first magnetic barrier, a second permanent magnet and a sixth permanent magnet which are arranged in an axial symmetry mode are embedded in the two magnetic barrier arms of the second magnetic barrier respectively, and a third permanent magnet and a seventh permanent magnet which are arranged in an axial symmetry mode are embedded in the two magnetic barrier arms of the third magnetic barrier respectively. And a fourth permanent magnet and a fifth permanent magnet which are asymmetrically arranged are respectively embedded in the magnetic barrier bottom edges of the second magnetic barrier and the third magnetic barrier. The magnetic barrier asymmetric rotor structure has the advantages of the magnetic barrier asymmetric rotor structure, can perform offset correction on the magnetic resistance shaft, and is adaptive to optimized motors of different models.

The invention discloses a switched reluctance motor for a chef machine, and particularly relates to the technical field of switched reluctance motors, the switched reluctance motor comprises a protective shell, the protective shell is provided with a regulation and control assembly, the regulation and control assembly comprises a base plate arranged in the protective shell, the top of the base plate is provided with a stator, and the bottom of the stator is rotatably connected with an extension rod; the extension rod is installed on the base plate through a bolt. According to the invention, by continuously changing the current in the stator, the reinforced rotor rod and the connecting shaft can continuously move, so that the reinforced magnetism-increasing sheets can be close to the connecting disc, and then the reinforced magnetism-increasing sheets extend between the two adjacent induction magnetic blocks, so that the magnetic field can be enhanced by the induction magnetic blocks and the reinforced magnetism-increasing sheets, and the voltage is kept unchanged; the waveform width, the peak value and the effective value of the current are changed, so that the output torque is influenced, and the torque of the rotor rod and the connecting shaft is further enhanced.

The invention discloses a magnetic encoder based on double vertical magnetic resistance units, and relates to the technical field of magnetic sensors, and the magnetic encoder comprises a first induction magnetic head, a second induction magnetic head and a signal processing assembly. The first induction magnetic head, the second induction magnetic head and the signal processing assembly are integrated into a magnetic encoder chip; the two groups of induction magnetic heads are arranged in a manner of being perpendicular to a packaging substrate of the magnetic encoder chip through 90-degree side installation, the signal processing assembly is horizontally laid on the plane of the substrate, and the mode of 90-degree side installation of the induction magnetic heads is innovatively adopted to directly induce the magnetic field angle of the multi-antipode magnets on the inner and outer rings of the permanent magnet coded disc; and the induction magnetic head and the signal processing assembly are integrated into one encoder chip, so that the system size is remarkably reduced, and the magnetic encoder is particularly suitable for application scenes where high-precision magnetic encoders need to be installed on various small mechanisms.

The invention relates to a current measurement method and device, computer equipment, a storage medium and a program product. The method comprises the following steps: acquiring the magnetic field intensity of the two sides of a monitoring point at the current moment through a first magnetoresistive sensor and a second magnetoresistive sensor which are deployed on the two sides of the same monitoring point of a power transmission line to obtain first magnetic induction intensity and second magnetic induction intensity; wherein the first magnetoresistive sensor and the second magnetoresistive sensor are located in the same electromagnetic environment; according to the first magnetic induction intensity, the second magnetic induction intensity and the error coefficient of the first magnetoresistive sensor and the second magnetoresistive sensor, the initial current value of the monitoring point at the current moment is determined, and the influence of the hysteresis effect on the current value is eliminated; and Kalman filtering processing is carried out on the initial current value of the monitoring point at the current moment to obtain the target current value of the monitoring point at the current moment, so that the accuracy of the measured current value is further improved.

The present invention discloses a novel combined vibration damping device with adjustable stiffness and damping, which relates to the technical field of vibration damping; it includes a magneto-resistive stress negative stiffness spring located inside the housing and a piezoelectric friction assembly located inside the bearing seat; a central shaft is connected between the two, and a metal helical spring is sleeved outside the central shaft. The bottom of the metal helical spring is connected to a spring base located at the top of the housing, and the top of the metal helical spring is connected to the bottom of the bearing seat; the central shaft is fixedly connected to the top inside the housing through a metal cross leaf spring. The magneto-resistive stress negative stiffness spring and the metal cross leaf spring can be connected in parallel to achieve the adjustment of quasi-zero stiffness, and the piezoelectric friction assembly can achieve the adjustment of damping; a load platform is fixedly arranged at the top of the bearing seat. The present invention has non-linear frequency-varying characteristics of high static stiffness - low dynamic stiffness, large low-frequency damping - small high-frequency damping, and can well solve the contradiction between the bearing capacity and the vibration damping frequency band, as well as the contradiction between high-frequency and low-frequency vibration attenuation, and achieve high-performance vibration damping.

The invention relates to the technical field of motors, in particular to a motor stator core. The motor stator core comprises a plurality of punching sheets, a plurality of pear-shaped grooves extending along the radial direction are uniformly distributed on the inner circumference of each punching sheet, and two adjacent surfaces of each pear-shaped groove are in fillet transition, so that magnetic field concentration of sharp edges is eliminated, and the problem of overhigh local magnetic flux density is reduced; the arc-shaped structure of the pear-shaped groove can provide a smoother magnetic path, magnetic resistance is reduced, magnetic lines are distributed more reasonably, magnetic hysteresis loss is reduced, and a magnetic circuit is improved. All the punching sheets are stacked in the axial direction, the pear-shaped grooves in all the punching sheets are in one-to-one correspondence to form a plurality of inclined notches, and compared with original vertical notches of the stator iron core, the inclined notches of the stator iron core have the advantages that the space for accommodating windings is increased, and the magnetic field density is improved. And the inclined notches enable the stator teeth and the rotor teeth to be not completely aligned, so that the tooth harmonic phases are different and mutually offset, thereby weakening the overall harmonic, reducing the electromagnetic noise and vibration, and further improving the motor performance.

A magnetoresistive element for a magnetic sensor, the magnetoresistive element including a tunnel barrier layer between a reference layer having a fixed reference magnetization and a sense layer having a free sense magnetization, wherein the sense magnetization includes a stable vortex configuration. The magnetoresistive element further includes a reference pinning layer in contact with the reference layer and pining the reference magnetization by exchange-bias at a first blocking temperature. The magnetoresistive element further includes a sense pinning layer in contact with the sense layer and pining the sense magnetization by exchange-bias at a second blocking temperature lower that the first blocking temperature. Additionally, a method for manufacturing the magnetoresistive element.

The invention relates to an internal rotation brushless motor for a treadmill, in particular to the technical field of motors for treadmills, a driving shaft is arranged at the center of a motor shell in a penetrating mode, the driving shaft is connected with the motor shell through a ball bearing, and rotor iron cores are arranged on the two sides of the middle of the driving shaft; the middle parts of the two groups of rotor cores are provided with permanent magnets, the inner wall of the motor shell is connected with a stator assembly, the back part of the stator assembly is provided with a tunnel reluctance element, the outer wall of one side of each rotor core is fixedly connected with a multi-pole magnetic coding ring, one side of the tunnel reluctance element is provided with a micro-electro-mechanical inertial measurement unit, and the outer wall of the rotor core is fixedly connected with a motor shell. The multi-pole magnetic coding ring fixed on the rotor side generates space magnetic field change, the tunnel magnetic resistance element array arranged in the circumferential direction captures magnetic field signals in real time, the Kalman filtering algorithm is fused with magnetic position signals, and detection errors caused by mechanical vibration are eliminated.

The invention provides a magnetic encoder. The magnetic encoder comprises a magnetic code disc and an in-plane orientation magnetoresistive sensor, two in-plane orthogonal magnetic fields generated by the magnetic code disc can saturate the magnetoresistive sensor, and the distance between the sensing center of the magnetoresistive sensor on the opposite plane and the midline of the corresponding magnetic track on the magnetic code disc is not smaller than one fourth of the width of the magnetic track. Wherein the opposite plane is parallel to the magnetic code disc; the sensing center of the magnetoresistive sensor module is the center of a sensing area formed by the plurality of magnetoresistive sensors; the center line of the magnetic track is a line formed by the center points of the magnetic track in the width direction. The precision of the magnetic encoder can be improved.

The invention discloses a full-band anti-shaking device, system and method, and belongs to the technical field of electromechanical servo systems, the device mainly comprises a multi-stage vibration reduction transmission shaft system and an electromagnetic-thermal coupling field regulation and control module, and the multi-stage vibration reduction transmission shaft system comprises a magnetorheological fluid layer, a piezoelectric anti-vibration power generation layer and an eddy current vibration reduction layer which are stacked on a rotating shaft in sequence; the magnetorheological fluid layer is used for low-frequency suppression, the piezoelectric anti-vibration power generation layer is used for medium-frequency absorption, and the eddy current vibration reduction layer is used for high-frequency braking; the electromagnetic-thermal coupling field regulation and control module realizes double-magnetic-circuit decoupling through a magnetic resistance network analysis method, and different types of currents are provided for the magnetic field array according to the magnitude of the vibration signal frequency. The system captures electric energy generated in the multi-stage vibration reduction transmission shaft system, is used for low-temperature self-heating and supplies power to the electromagnetic-thermal coupling field regulation and control module. According to the invention, full-band vibration suppression and energy closed-loop utilization are realized through a multi-stage energy consumption structure and an electromagnetic-thermal cooperation mechanism.

The invention provides a Z-axis magnetic field sensor. The Z-axis magnetic field sensor comprises a plastic packaging layer, a magnetic resistor Die, a plurality of pins and a first shielding layer. And the first shielding layer is arranged on the upper surface of the magnetoresistive Die and consists of a plurality of soft magnetic material blocks in an X-Y plane so as to shield a magnetic field in the X-Y direction on the upper surface of the magnetoresistive Die. The magnetic resistor Die is manufactured by adopting a wafer front-end process and comprises a magnetic resistor and a Z-axis magnetic field conversion part above the magnetic resistor. Each welding spot on the upper surface of the reluctance Die is directly covered by an independent soft magnetic material block in the first shielding layer to form a wiring end, and each pin is in one-to-one correspondence contact with the welding spot. The Z-axis magnetic field sensor provided by the invention is manufactured by combining a semiconductor front-end process and a special packaging process, so that the volume size is effectively reduced, an XY plane interference magnetic field is shielded more thoroughly, and the anti-interference capability is stronger.

The invention discloses a magnetoresistive element and sensing equipment, and relates to the technical field of magnetic field measurement. The magnetoresistive element comprises at least one magnetoresistive sub-element, the magnetoresistive sub-element comprises a plurality of bridge arms, and the bridge arms are mutually coupled to form a Wheatstone bridge structure; at least one bridge arm comprises a magnetic resistance bridge arm and a compensation resistor, and the compensation resistor is coupled with the magnetic resistance bridge arm in parallel and used for enabling the resistance of the bridge arm to be lower than that of the magnetic resistance bridge arm; the magnetic resistance bridge arm comprises at least one magnetic tunnel junction, each magnetic tunnel junction has the same magnetic sensitive axis, and the magnetic sensitive axis is parallel or perpendicular to the free layer plane. The bandwidth of the magnetoresistive element is expanded by adjusting the resistance of the bridge arms in the magnetoresistive element, so that the magnetoresistive element can be further used for measuring electrical variables such as high-frequency current, and the magnetoresistive element has the advantages of being simple in structure and easy to implement.

The invention belongs to the technical field of nondestructive defect detection, and particularly relates to a method for detecting cracks in any direction in carbon steel based on magnetic resistance disturbance. The crack detection method comprises the following steps: applying a static magnetic field to magnetically conduct a carbon steel structure to a high-sensitivity stage; and then exciting an alternating-current magnetic field in an excitation range defined on the surface of the carbon steel structure to be detected, and counting the change condition of the magnetic conductivity of the carbon steel structure, so that effective identification and detection of internal cracks in any direction are realized. The crack detection method comprises the following steps of: magnetizing a carbon steel structure to be detected to the left side of a peak value of a magnetic conductivity curve by using a static magnetic field B0; defining an excitation range on the surface of the carbon steel structure to be detected, and exciting an alternating current magnetic field B1 in the excitation range; collecting an alternating current magnetic field B1 and a secondary alternating current magnetic field B2 in the excitation range, and converting to obtain a signal Bx; obtaining an alternating current component JBx and a direct current component ZBx; and moving the alternating-current magnetic field B1 in the excitation range, and counting the change trend of the alternating-current component JBx.

An MR element includes a first magnetic layer, a second magnetic layer, and a nonmagnetic layer disposed between the first magnetic layer and the second magnetic layer. The first magnetic layer has a magnetic shape anisotropy set in a first reference direction, and has a magnetization whose direction changes depending on an external magnetic field, the magnetization being oriented in a first magnetization direction in a state where the external magnetic field is not applied. The second magnetic layer has a magnetic shape anisotropy set in a second reference direction, and has a magnetization whose direction changes depending on the external magnetic field, the magnetization being oriented in a second magnetization direction in a state where the external magnetic field is not applied.

The invention provides a system for measuring an absolute position. The system comprises a strip-shaped magnetic track with only one pair of N-S poles, a magnetic head with magnetic resistors R1, R2, R3 and R4, and a calculation module. The N pole and the S pole of the strip-shaped magnetic track integrally form a rectangle, and straight line boundaries between the N pole and the S pole are neither parallel nor perpendicular to the strip-shaped magnetic track. And the magnetic resistors R1, R2, R3 and R4 have the same sensitive direction, are parallel or perpendicular to the strip-shaped magnetic track, and are distributed in the width direction (perpendicular to the strip-shaped magnetic track) of the strip-shaped magnetic track at equal intervals. And the calculation module obtains the absolute position of the magnetic head directly facing the strip-shaped magnetic track according to the sensing signals of the magnetic resistors R1, R2, R3 and R4. According to the technical scheme provided by the invention, the absolute position is detected by using a single magnetic track, magnetic field components in different directions of the same position point do not need to be measured (different magnetic resistors are actually not feasible to be placed at the same space point), and the measurement precision is effectively improved on the basis of reducing the size of an absolute position measurement system.

The invention relates to a tunnel reluctance current sensor structure and temperature parameter optimization method and system, and the method comprises the steps: arranging an annular magnetic core, forming symmetrically distributed air gaps in the annular magnetic core, placing a tunnel reluctance current sensor in each air gap, and forming a double-air-gap magnetic circuit structure; constructing a magnetic field consistency coefficient according to the average magnetic induction intensity, the minimum magnetic induction intensity and the maximum magnetic induction intensity of the air gap center area, and performing optimization solution on structural parameters of the double-air-gap magnetic circuit structure by taking minimization of the magnetic field consistency coefficient as a target; respectively establishing a measurement channel and a reference channel according to the double-air-gap magnetic circuit structure obtained through optimization solution; multiple times of voltage signal acquisition are carried out through a reference channel under different injection reference currents and different temperature environments, and a temperature compensation factor is calculated, so that gain parameters of an amplifier in a measurement channel are adjusted. Compared with the prior art, the anti-interference capability and the measurement sensitivity of the system can be greatly improved.