1971results about "Voltage/current isolation" patented technology

The invention relates to the field of on-line monitoring of electrical equipment, in particular to an on-line monitoring method of the electrical equipment, which comprises the following steps: acquiring multi-dimensional monitoring parameters of the electrical equipment, including an electrical parameter, a temperature parameter and an insulation parameter; performing feature extraction on the collected multi-dimensional monitoring parameters to obtain feature parameters corresponding to the monitoring parameters, and constructing a feature vector set; based on historical normal operation data and real-time acquisition data of the electrical equipment, establishing a dynamic threshold model, and calculating a threshold corresponding to the characteristic parameter through the dynamic threshold model; feature parameters in the feature vector set are compared with corresponding thresholds output by the dynamic threshold model, and whether the electrical equipment is abnormal or not is judged; when the abnormity exists, outputting an abnormity monitoring result; and if not, returning to S1. According to the invention, by collecting multi-dimensional parameters, calibrating, correcting, de-noising and extracting features, and combining historical and real-time data to build a model and verify, data preprocessing, threshold adaptation and anomaly judgment are realized, and the monitoring reliability is improved.

The invention provides a current sensor. The current sensor adopts a magnetic-core-free design, and adopts a diversion row group with a special structure to guide a target current so as to enhance the electrifying capability of the current sensor and reduce the adverse effect of a high-frequency current skin effect on measurement. Based on the structural characteristics of the diversion row group, the magnetic sensitive component for measuring the target current and the corresponding sensing signal processing method are arranged in a matched manner, so that the measurement precision of high-frequency large current is improved, the suppression capability of an interference magnetic field is improved, and the signal-to-noise ratio of an effective measurement signal is increased. The current sensor provided by the invention is compact in structure, simple in manufacturing process, strong in electrifying capability and high in signal-to-noise ratio of a sensing signal, not only widens the measuring range of the current sensor, but also effectively improves the measurement precision of high-frequency large current, and expands the application range of the magnetic-core-free current sensor.

The invention relates to the technical field of power equipment operation and maintenance and state monitoring, in particular to an optical fiber transformer health state assessment method and system based on feature fusion. According to the invention, sampling signals of a plurality of optical fiber current transformers are collected and preprocessed; constructing a historical data matrix for principal component analysis, establishing a principal component space and calculating a square prediction error control limit value; constructing a simulated fault data set and projecting the simulated fault data set to a principal component space to calculate a square prediction error time sequence; performing wavelet packet decomposition on the square prediction error time sequence to extract a normalized energy feature vector, and training a one-dimensional convolutional neural network model; projecting the real-time sampling signal to a principal component space to judge whether the real-time sampling signal exceeds the limit or not; if yes, the health state level is output through the trained model. According to the invention, accurate grading and real-time online evaluation of the health state of the optical fiber transformer are realized.

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 turn-to-turn short-circuit fault diagnosis method and system for a reactor, and a medium. The method comprises: using operating data of a reactor to be tested to plot a target Bowditch curve of said reactor (101); calculating feature parameters of the target Bowditch curve (102); inputting the target Bowditch curve into a preset embedded target diagnosis network model, so as to extract a feature map of the target Bowditch curve (103); using the feature parameters and the feature map of the target Bowditch curve to generate feature information (104); and comparing whether the feature information is consistent with preset feature information, and on the basis of a comparison result, determining a fault state of said reactor (105). The method solves the technical problem of existing detection methods having poor sensitivity and being unable to detect incipient turn-to-turn short-circuit conditions of reactors in a timely manner, and realizes the real-time detection and determination of turn-to-turn short-circuit faults in dry-type air-core reactors.

The invention relates to the technical field of power system automation, in particular to a node fault monitoring method and system for a direct current power distribution network, electronic equipment and a medium, and the method comprises the steps: injecting a difference frequency band signal into each measurement node on the direct current power distribution network, and obtaining an initial signal propagation feature set from each measurement node; distinguishing from the initial signal propagation characteristic set according to the shunting effect intensity of the distributed capacitance on the signal under each difference frequency band to obtain a high shunting frequency band subset and a low shunting frequency band subset; and a far-end fault frequency band subset is extracted from the high-shunting frequency band subset and the low-shunting frequency band subset, so that the fault position and type in the direct-current power distribution network can be calculated. By means of the mode, the technical problem that in the prior art, the fault positioning precision and the detection range of the direct-current power distribution network conflict with each other is solved, dynamic monitoring of the insulation defect propagation characteristics is achieved, and the fault positioning accuracy and the system reliability are improved.

The invention discloses a wear state and precision degradation prediction method for a ball screw drive system, and the method comprises the steps: employing a dual-label obtaining strategy, and constructing a'strong label + weak label 'mixed label sequence covering a whole life cycle; mapping a macroscopic working condition into a contact interface micromechanical state quantity, and converting a time domain signal into a travel domain / space domain stable sequence by adopting equal travel synchronous resampling, so as to weaken the influence of speed fluctuation on feature extraction; a double-flow physical guidance neural network is further constructed, and a physical attention mechanism is introduced to realize data feature and physical prior fusion; training is completed based on supervision loss and physical consistency constraint, and online recursive correction is carried out by using sparse laser interferometer calibration data. By adopting the method, the prediction deviation caused by equipment aging and working condition change can be reduced, and stable prediction of the wear state and the repeated positioning error degradation trend is realized.

The invention relates to the technical field of optical current transformer detection, and provides an optical current transformer real-time calibration and health diagnosis method and system, and the method comprises the steps: carrying out the harmonic analysis of an initial digital signal sequence obtained through the conversion of a continuous modulation optical signal of a target optical current transformer, and obtaining harmonic component data; physical state evaluation is carried out according to the higher harmonic component data and preset health state baseline data to generate a physical state evaluation result, nonlinear disturbance compensation is carried out according to an error control signal generated based on the higher harmonic component data, and after a linear working point is reached, nonlinear disturbance compensation is carried out; and calculating an electrical measurement value according to the output target fundamental component data, and performing comprehensive analysis according to the physical state evaluation result and the electrical measurement value to generate a diagnosis report. According to the invention, through a measurement calibration and state diagnosis mechanism based on harmonic analysis, while the electrical performance measurement precision is effectively improved, reliable quantitative diagnosis and accurate traceability of different physical faults in the equipment are realized.

The invention discloses a current sensing measurement device and method, a storage medium and electronic equipment, and the device comprises an AC detection module which is used for sensing an AC current and outputting an AC current analog signal; the direct-current compensation module is used for acquiring magnetic induction intensity generated by a direct-current component of the detected current and outputting a differential voltage analog signal; the compensation module is used for outputting compensation current which is equal to the direct-current component in size but opposite to the direct-current component in direction based on the compensation control signal output by the signal processing module so as to offset direct-current magnetic flux generated by the direct-current component; and the signal processing module is used for calculating a direct current component, a compensation current and an alternating current based on the alternating current analog signal and the differential voltage analog signal, and outputting the compensation control signal based on the direct current component. According to the invention, direct current interference can be effectively suppressed, air gap nonlinear errors can be compensated, influences caused by environmental changes and equipment aging can be adapted, high precision and high reliability of a measurement system can be maintained during long-term operation, and the requirement of high-precision field calibration can be met.

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 invention belongs to the technical field of gap measurement, and particularly relates to a high-temperature-resistant transparent shell type eddy current tip gap measuring device and method, and the device comprises a sensor probe module, a signal conditioning module, a data collection module and a data processing module. The sensor probe module is mounted on the outer wall of the casing; the sensor probe module comprises a permanent magnet excitation source, a soft magnet magnetic core and a receiving coil; the signal conditioning module is electrically connected with the receiving coil and is used for amplifying, filtering and integrating the weak induction signal; the data acquisition module is electrically connected with the signal conditioning module and converts an analog signal into a digital signal; the data processing module is used for processing the acquired digital signals and extracting blade tip clearance information.

A system includes: an inverter configured to convert DC power to AC power, wherein the inverter includes: a power module including: a first substrate, a second substrate including a source plane and a gate plane separated from the source plane by a full trench, the source plane including a step trench, and the gate plane including an electrical connection through the second substrate to a gate input connection of the power module, a semiconductor die disposed between the first substrate and the second substrate, the step trench formed in a portion of the source plane corresponding to an edge of the semiconductor die, and the semiconductor die including a gate connected to the gate plane, and a sinter element disposed between the semiconductor die and the second substrate to connect the semiconductor die to the second substrate; a battery; and a motor.

The embodiment of the invention provides a real-time collection method and system for welding heat input, and the method comprises the steps: sensing the displacement movement of a welding gun or a welding wire through a diffuse reflection photoelectric switch array installed on the surface of a pipeline, and generating a corresponding pulse trigger signal; current data and voltage data of a welding loop are sensed through a Hall sensing system, and corresponding analog electric signals are generated; synchronously acquiring the pulse trigger signal and the analog electric signal through a multi-channel data acquisition device, and converting the analog electric signal into a digital signal with a timestamp; real-time welding speed data are calculated according to the time sequence of the pulse trigger signals and the preset space geometrical relation of the diffuse reflection optoelectronic switches; performing multi-stage filtering processing on the current data and the voltage data; a unified timestamp is determined, and time sequence matching is conducted on the filtered current data, the filtered voltage data and the filtered welding speed data based on the unified timestamp; and calculating to obtain a welding heat input value.

The invention provides a miniature breaker with a novel current detection assembly. The miniature breaker with a novel current detection assembly includes a breaker main body and a novel current detection assembly, wherein the novel current detection assembly includes a Hall magnetic field sensor, a current detection wire, and a Hall magnetic field sensor detection circuit board; a detection Hallmagnetic field sensor in the Hall magnetic field sensor without a magnetic core is used to detect a magnetic field which is generated from the current detection wire, and an environment Hall magneticfield sensor in the Hall magnetic field sensor is used to detect a background magnetic field in the environment; and the difference values detected by the detection Hall magnetic field sensor and theenvironment Hall magnetic field sensor are processed to obtain the magnitude of the current, so as to eliminate the interference of the background magnetic field and enable the detected current to bemore accurate. Therefore, the breaker with the novel current detection assembly can accurately perform opening and closing.

The invention belongs to the field of power equipment monitoring, and discloses a lightning arrester on-line monitoring system and method based on non-contact differential electric field probe self-adaptive compensation, a non-contact differential voltage probe is adopted, the sensitivity to environmental noise and interference to other-phase high-voltage buses is remarkably reduced through differential measurement, and the monitoring accuracy is improved. And the self-adaptive compensation algorithm is combined, so that the measured signal can be corrected in real time according to the on-site electromagnetic environment change, the amplitude and phase distortion can be effectively inhibited, the accuracy and reliability of the high-voltage side bus voltage acquisition can be improved, and the overall monitoring precision can be obviously improved. According to the invention, high-sensitivity and wide-dynamic-range measurement of lightning arrester current is realized by adopting the fluxgate weak current sensor, accurate detection under small signals is guaranteed, and fine analysis of harmonic components is facilitated.

The invention discloses a ring main unit cable line fault positioning system and method based on traveling wave intelligent sensing, and relates to the technical field of ring main unit cable line fault positioning, and the method comprises the following steps: arranging a traveling wave sensor at a position corresponding to a cable connecting plug or a solid-sealed polar pole in a ring main unit; an initial correction stage is carried out, a known electrical event is triggered on a cable in actual operation, the propagation time of a traveling wave signal between the two ends is measured, and the wave velocity of the traveling wave is actually measured on site and dynamically updated in combination with the known cable length; the method comprises the following steps: executing initial correction under different operation conditions, collecting corresponding data of working conditions and wave velocities, constructing a self-adaptive model of the wave velocities and working condition parameters, and when a fault occurs, dynamically predicting the wave velocities based on the constructed model according to current working condition parameters monitored in real time; and on the basis of the identified wave head timestamp, constructing an overdetermined equation set and solving an optimal fault position, so that the cable line fault positioning of the ring main unit is realized.

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.

The invention discloses a high-precision zero magnetic flux compensation method, which comprises the following steps of: acquiring a detected current signal, and generating a magnetic field detection interface structure after noise reduction, frequency band extraction and magnetic sensitive configuration processing; performing magnetic field analysis, feature matching and resource optimization based on the data to generate efficient compensation parameters; final compensation output is generated through interference identification, compensation recombination and power adaptation; generating a calibration trigger mark through standard value comparison, stability evaluation and threshold judgment; and finally, forming a closed-loop calibration instruction set through type identification, strength calculation and time sequence arrangement, and completing parameter updating and verification. According to the invention, the precision and stability of current measurement are significantly improved, the interference of a complex environment is effectively suppressed, and the characteristics of strong adaptability and low power consumption are achieved.

The invention provides a current sensor. According to the current sensor, four identical magnetic sensing parts are arranged at corresponding positions on the upper side and the lower side of a current guide row, the sensing centers of the four magnetic sensing parts are symmetrical about the current guide row in pairs, and the sensing direction is parallel or antiparallel to the row width direction of the current guide row. The current guide bar is a flat metal conductor so as to counteract the influence of current on any two magnetic sensitive parts symmetrical about the current guide bar. In cooperation with the hardware setting, target signals capable of representing the magnitude, the phase and the frequency of the current in the diversion bar are obtained through corresponding sensing signal processing, meanwhile, the influence of constant interference fields in all directions is eliminated, and three-dimensional interference resistance is achieved. In addition, according to the current sensor provided by the invention, the four magnetic sensing parts and the signal conditioning unit are arranged on the PCBs stacked on the upper side and the lower side of the diversion row, so that the current sensor is compact in structure and small in size.

The invention discloses a quantum double-ring cooperative current measurement device and method, and belongs to the technical field of electric measurement. The device comprises an outer ring unit used for measuring a high-frequency signal in current; the inner ring unit is used for measuring a low-frequency signal in the current; the digital signal processing unit is used for carrying out synchronous high-speed ADC sampling on the high-frequency signal measured by the outer ring unit and the low-frequency signal measured by the inner ring unit, carrying out fast Fourier transform on the sampled signal and converting the sampled signal into a frequency domain to obtain a VTMR (f) signal and a delta fNV (f) signal, and calculating the VTMR (f) signal and the delta fNV (f) signal to obtain the VTMR (f) signal and the delta fNV (f) signal. And reconstructing the full-band current waveform of the time domain. According to the invention, the measurement accuracy and reliability of the current sensor in broadband, high harmonic and strong interference scenes can be significantly improved, and the method is suitable for the fields of new energy grid connection, flexible direct current transmission, power grid protection, high-precision measurement and the like.

The invention discloses a cable warning pile and method for monitoring the state of an intermediate joint of a directly-buried power cable, relates to the field of state monitoring of power equipment in power engineering, and aims to solve the problems of single-parameter acquisition, large interference influence, non-objective evaluation and non-visual early warning in the existing monitoring technology. The warning pile is vertically buried at the position 0.3-0.8 m above a connector, temperature, partial discharge, vibration and environment data are synchronously collected through multiple sensors such as an optical fiber temperature sensor and a high-frequency current transformer, after data alignment, abnormal value elimination, filtering and integral preprocessing, the real temperature of the connector is restored through an environment and vibration coupling correction model, and the real temperature of the connector is obtained. And extracting a partial discharge peak factor and an average discharge capacity core characteristic. An index weight is determined based on an entropy weight method to construct a health degree evaluation model, operation states are divided into normal, attention, early warning and fault classes, hierarchical visual warning is realized through a three-color indicating lamp group and a buzzer, and the model is dynamically updated in combination with maintenance data every three months.

The invention relates to the technical field of power fault detection, and mainly relates to a residual voltage detection circuit and a line protection device.The residual voltage detection circuit comprises a sampling circuit and a signal holding circuit, the signal holding circuit adopts double coils and comprises a first coil and a second coil, and a loop where the first coil is located is provided with a first controllable switch tube in series; the first controllable switch tube is connected when the sampling circuit collects residual voltage, a second controllable switch tube is arranged in a loop where the second coil is located in series, the control end of the second controllable switch tube is used for being connected with a feeder terminal, and the signal holding circuit further comprises a residual voltage output branch used for being connected with the feeder terminal. The residual voltage output branch is provided with a first contact of the double coils in series. A sampling circuit is used for obtaining a residual voltage signal generated at the moment of closing of a faulty power grid line, and a signal holding circuit formed by double coils is used for transmitting a sampling signal to a feeder terminal, so that the feeder terminal can still receive the residual voltage signal when the feeder terminal loses power after power supply is recovered.

The invention relates to a hydro-generator partial discharge pulse extraction method based on Taylor-S transformation. The method comprises the following steps: collecting a partial discharge signal of a stator winding of a hydro-generator; preprocessing the partial discharge signal to obtain a preprocessed signal; performing time-frequency transformation on the preprocessed signal to obtain a time-frequency matrix; estimating an instantaneous frequency based on phase information of the time-frequency matrix; synchronously extracting the time-frequency matrix according to the instantaneous frequency to obtain a time-frequency energy matrix; extracting a time-frequency ridge line based on the time-frequency energy matrix, and performing feature optimization on the time-frequency ridge line to obtain an optimized ridge line; and determining starting and ending positions of the partial discharge pulse according to the time-frequency energy matrix and the optimized ridge line. According to the method, Taylor-S transformation is combined with synchronous extraction operation, so that the problems of energy dispersion and serious cross term interference in a strong noise environment of a traditional time-frequency analysis method are effectively solved, and the definition and focusing property of partial discharge pulse time-frequency representation are remarkably improved.

The invention discloses a current transformer based on decoupling compensation and an adjusting method thereof, and relates to the technical field of current measurement. The method comprises the following steps: establishing an error coupling matrix by data acquired by a current transformer; a decoupling compensation hardware module is designed, and decoupling compensation is carried out on the exciting current, the secondary load and the transient component; establishing a working condition parameter set, and constructing a training sample library by taking the working condition parameters as input and the compensation coefficients as output based on a BP neural network; through a clock synchronization module, it is ensured that output signals of the three compensation units and current signals of the secondary side of the mutual inductor are the same in frequency and phase; different working conditions are simulated through the standard current source, and the adjusted precision is recorded. According to the invention, through multi-dimensional error decoupling and combination of the BP neural network and the PID, hardware shunting and algorithm optimization are utilized to realize separated compensation of three errors, the method is adaptive to complex working conditions, and the adjustment precision of the compensation circuit is improved.

The invention discloses a power frequency waveform classification method and device, a medium and equipment, and belongs to the field of waveform classification, and the method comprises the steps: obtaining preprocessed power frequency waveform data of a power transmission line, calculating various waveform features, and inputting the features into a preset cascade classifier model. The model is composed of a plurality of XGBoost binary classifiers which are cascaded in sequence, and each classifier is responsible for executing a specific binary classification task. The output result of the previous classifier is used for triggering the starting of the next classifier, or the final classification result is directly output. The cascade structure not only improves the accuracy and efficiency of classification, but also reduces the complexity of the model, and effectively solves the problem that the fault positioning power frequency of the power transmission line cannot be accurately and efficiently classified in the prior art.

The invention discloses a synchronous generator rotor turn-to-turn fault online monitoring method and system, and the method comprises the steps: building a time-varying parameter mathematical model which comprises a stator branch, a normal excitation loop, an excitation fault additional loop, a damping loop and a load based on a multi-loop theory, and collecting the current signals and key-phase signals of all parallel branches of a stator in real time; the fractional harmonic characteristic quantity representing the fault is extracted through analysis, and whether turn-to-turn short circuit occurs or not is judged according to a preset criterion; and if the fault is determined, determining the position of the fault magnetic pole by adopting a phase matching algorithm in combination with the key-phase signal and the magnetic pole fault characteristic angle database. According to the method, the primary side of the generator does not need to be transformed, high-sensitivity online monitoring and accurate positioning of rotor turn-to-turn faults in operation can be achieved, and the method is suitable for safety guarantee of an active-service unit.

The utility model, which relates to the technical field of the LED, discloses a leakage protection circuit comprising a power supply circuit, a step-down circuit, an LED circuit and a detection circuit. The input end of the power supply circuit is connected to the output pin of the power supply end, the output end of the power supply circuit is connected with the input end of the step-down circuit and the input end of the LED circuit, and the power supply circuit is used for rectifying the output power supply of the power supply end so as to output the power supply to the step-down circuit and the LED circuit; the output end of the step-down circuit is connected with the detection circuit, and the step-down circuit is used for carrying out step-down processing on the power supply output by the power circuit to output reference voltage to the detection circuit; and the detection circuit is respectively connected with the output pins of the power supply end and the LED circuit, and is used for controlling the working state of the LED circuit according to the real-time voltage difference and the real-time voltage between the output pins of the power supply end and the reference voltage output by the step-down circuit. According to the utility model, the working state of the LED circuit can be controlled according to the real-time voltage difference, the real-time voltage and the reference voltage, thereby realizing anti-creeping protection.

The quantum current transformer based on the optical fiber isolation microwave transmission comprises a high-voltage primary side which comprises a magnetic shielding ring and an NV color center magnetic sensing probe module, and a magnetic sensing probe is arranged in the magnetic shielding ring; at the low-voltage secondary side, the microwave system is used for generating radio-frequency signals in a preset frequency range and transmitting the radio-frequency signals to the NV color center magnetic-sensing probe module, the laser system is used for generating continuous laser and transmitting the continuous laser to the NV color center magnetic-sensing probe module, and the microwave system and the laser system are used in cooperation to drive the NV color center to generate fluorescence signals representing the magnetic field intensity. A fluorescence signal is transmitted to the data processing system to calculate to-be-detected current information; wherein the microwave system is connected with the NV color center magnetic sensing probe module through an optical fiber, the microwave system modulates the radio frequency signal into an optical signal, transmits the optical signal to the NV color center magnetic sensing probe module, and restores the optical signal into the radio frequency signal in the NV color center magnetic sensing probe module to be received. According to the transformer, stable transmission of microwave signals under the high-low voltage isolation condition is achieved, the design is reasonable and exquisite, and the measurement precision is high.

The invention provides an alternating-current weak current high-precision detection system and method, and the system comprises a copper-nickel alloy shielding cover which is used for inhibiting space power frequency radiation interference and power system broadband noise, and a magnetic sensitive element which is used for converting the detected magnetic field change into a corresponding initial current signal, the trans-impedance amplifier is used for converting the initial current signal into a voltage signal; the adaptive noise suppression module collects a power frequency fundamental wave reference signal and a harmonic wave reference signal, generates a harmonic wave anti-phase counteracting signal, and performs anti-phase counteracting on real noise of the initial current signal; the analog-to-digital converter is used for converting the voltage signal into a discretized digital signal, and the discretized digital signal comprises a target signal and a random noise signal; and the FPGA coherent demodulation module is used for carrying out cross-correlation operation and narrow-band filtering on the target signal and the random noise signal to separate out a micro-current signal. The technical problems that in the prior art, composite noise covering is limited, the frequency fluctuation adaptability is poor, and microvolt-level signals are difficult to capture are solved.

A measurement circuit including a power supply, a load output terminal connected to the power supply and connected to a system ground via a load, an amplifier comprising power terminals connected to the power supply, and an output terminal connected to the system ground via a measurement resistor, the amplifier is configured to supply current from the power supply to the load via the measurement resistor and the system ground producing a voltage across the measurement resistor that corresponds to the supply current through the load.