706 results about "Excitation current" patented technology

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.

The invention discloses a phase modifier unit state monitoring and load control method and system for reactive power compensation of a power grid, belongs to the technical field of automatic control of power systems, and mainly solves the problem that service life loss is aggravated or a control target is single due to the fact that the health state of equipment is not fully considered when an existing phase modifier unit responds to reactive power requirements of the power grid. The method comprises the following steps of: calculating reactive vacancy and extracting vibration frequency band energy characteristics by acquiring voltage and frequency of a power grid as well as vibration, temperature and exciting current signals of a unit in real time, and constructing a health state index HSI in combination with self-adaptive wavelet basis selection; taking minimum equipment life loss and optimal power grid voltage stability as multiple objectives, dynamically generating a load control instruction by adopting a particle swarm algorithm, realizing weight adaptive adjustment based on HSI, and introducing an online life loss model as a constraint condition; finally, reactive power output is adjusted through an excitation system, and cooperative control of power grid stability and equipment life extension is achieved.

The present invention provides a topology, method and system for bi-directional power conversion of excitation power supply for power battery testing, wherein the topology comprises a three-phase PWM (pulse width modulation) converter, a high-frequency isolation three-level LLC (logical link control) resonant converter and a DC-DC (direct current) converter forming a topology structure for a three-stage power conversion; an input end of the three-phase PWM converter is connected to a power grid side; the high-frequency isolation three-level LLC resonant converter is connected between the three-phase PWM converter and the DC-DC converter in series and is configured for realizing bi-directional DC voltage conversion and isolation, and to raise a busbar voltage between the high-frequency isolation three-level LLC resonant converter and the DC-DC converter; and, the DC-DC converter is configured to generate charging and discharging excitation currents for a power battery testing.

The invention discloses a synchronous generator excitation method based on mathematical modeling and gain scheduling, and relates to the technical field of synchronous generator control, and the method comprises the steps: building a synchronous generator global dynamic mathematical model comprising the electromagnetic dynamic characteristics of a stator winding, a rotor winding and a damping winding through a modeling module; a discretization simulation platform is constructed in a Matlab / Simulink environment by utilizing a simulation module, model parameters are corrected, dynamic adjustment is realized through a gain scheduling excitation controller, an automatic voltage regulator (AVR) adopts PID (Proportion Integration Differentiation) control and comprises a voltage deviation integral separation strategy, and a power system stabilizer (PSS) dynamically adjusts parameters of a lead-lag compensator based on active power. According to the method, the deviation between a model and an actual system can be reduced by more than 30%, the electromechanical oscillation damping ratio within the rated power range of 10%-150% is increased by 25%-40%, the harmonic content of exciting current is reduced to be lower than 5%, the stability of an electric power system and the electric energy quality are remarkably improved, the engineering practicability is high, and the method is easy to transform and upgrade on an existing synchronous generator.

The invention discloses a magnetic adjustment water lubricated bearing and a bearing support control method, which are applied to a large ship propulsion shaft system, and comprise a bearing shell, an electromagnetic excitation module, a batten, a sensor module, a power supply driving module and a control system, a plurality of mounting grooves are formed in the bearing shell; an electromagnetic excitation module is arranged in each mounting groove and generates a variable magnetic field with set intensity; a plurality of magnetically soft alloy segments are arranged on the batten, the magnetically soft alloy segments correspond to the electromagnetic excitation modules one to one, and a magnetic field acts on the magnetically soft alloy segments to generate electromagnetic attraction force; the control system independently controls the excitation current of each electromagnetic excitation module according to data of the sensor module, and generates magnetic fields with different intensities to act on soft magnetic alloy areas at corresponding positions, so that precise control of local supporting rigidity and lubricating gaps of the water-lubricated bearing is realized, unbalance loading and abnormal wear risks are effectively reduced, and the service life of the water-lubricated bearing is prolonged. And the adaptive capacity of the bearing under low-speed heavy load and dynamic disturbance is improved.

The invention belongs to the technical field of power system operation and motors, and particularly relates to an energy storage type phase modifier control method which comprises the steps that a rotating shaft of a double-fed motor is connected with a flywheel to serve as an energy storage type phase modifier; the rotor winding is connected to a power grid through an excitation system and a transformer in sequence, and the excitation system is electrically connected by a reactor, a back-to-back converter and a filter in sequence; the stator winding is directly connected to a power grid; the control system decouples reactive power and active power, vector control is carried out on exciting current to absorb or release power, and reactive power-voltage support and active power-frequency support of the power grid are completed. The method overcomes the defects that a traditional direct-current excitation phase modulation mode can only modulate phase and cannot modulate frequency, or is cumbersome and slow in response. The system can meet the requirement of wide-range variable-speed operation, quickly store / release a large amount of rotor kinetic energy, inhibit the voltage and frequency fluctuation of a power grid, and is especially suitable for stations with high new energy occupation ratio. The invention also provides a non-transitory readable recording medium storing the program of the method and a system comprising the medium, and the program can be called through a processing circuit to execute the method.

The utility model relates to the field of resonance eliminators, and discloses a protection element and a current limiting type resonance eliminator, the protection element comprises at least two groups of protection units, the two adjacent groups of protection units are connected in series, and each protection unit comprises a protection module; the current-limiting resonance eliminator based on the current-sensitive resistor made of the current-sensitive material is connected in series between the PT neutral point and the ground. Under the normal operation condition, the current-limiting resonance eliminator is in a low-resistance state, and system parameters and PT performance are not affected; when excitation energy is generated due to a system fault, the current-limiting resonance eliminator suddenly changes into a high resistance state, quickly absorbs resonance energy, destroys resonance parameters, suppresses PT excitation current below 200mA, and ensures that a voltage transformer is unsaturated and a PT fuse is not fused; and a built-in current sensor is connected, so that the running state of the current-limiting resonance eliminator can be monitored in real time.

The invention relates to a method. The invention discloses an ATE-based method for batch detection of pseudo soldering and sealing-off of chip packaging bonding, and belongs to the technical field of semiconductors. The method comprises the following steps: aiming at packaged and bonded chips, providing excitation current for each chip to be tested through an ATE test machine, and conducting an ESD (Electro-Static Discharge) diode connected with each pin of the chip; detecting the voltage drop between each pin and the pin GND; and calculating the equivalent resistance to determine whether pseudo soldering or unsoldering exists. The detection method has high practicability, is simple to operate, is very suitable for large-scale application and popularization, and has a certain promotion effect on improvement of a chip packaging test technology, improvement of chip performance reliability and chip packaging inspection.

The invention provides an electromagnetic quasi-zero stiffness vibration isolator and a control method, and belongs to the technical field of vibration isolation. The vibration isolator comprises a base, a positive stiffness mechanism, a negative stiffness mechanism, a positive and negative stiffness connecting mechanism and a dynamic control module. The positive stiffness mechanism adopts a hydraulic spring to provide basic positive stiffness; the negative stiffness mechanism comprises a plurality of stator units distributed on the base in an annular array and a rotor suspended in the center of a magnetic field of the stator units, and is used for generating nonlinear negative stiffness; the top end of the hydraulic spring supports a load through the bearing table and keeps a preset gap with the inner wall of the rotor; the positive and negative stiffness connecting mechanism realizes displacement transmission and cooperative adjustment; the dynamic control module comprises a displacement sensor and a controller, the sensor collects displacement signals, and the controller adjusts excitation currents of the stator units according to the signals and dynamically adjusts electromagnetic force, so that the vibration isolator is kept in a quasi-zero stiffness state. The quasi-zero stiffness state can be still kept when the load changes, load self-adaption low-frequency vibration isolation is achieved, and the system stability and the vibration isolation performance are improved.

The invention discloses an automobile generator self-adaptive excitation control method based on load prediction, and relates to the technical field of automobile electrical control, and the method comprises the following steps: injecting a micro-amplitude identification pulse into a whole vehicle electrical system, capturing the dynamic response of an electrical load, building a load transition curvature map, marking a high-risk time window, and generating a buffer time slot; and in the buffer time slot, constructing a prediction model fusing time domain extrapolation calculation and frequency domain envelope regression, and outputting collaborative confidence with credibility. A load transition curvature map is constructed to identify a high-risk window, a time domain and a frequency domain are fused to predict output confidence, excitation current is guided to form an anti-shake track, and a dynamic adjustment path is generated by combining start-stop broadening of high-power equipment and voltage second-order derivative identification. And finally, a slew rate self-adaptive strategy is introduced at a chip end to reduce peak impact, power supply and chip cooperative protection is realized, and system robustness and intelligent driving electrical safety are improved.

The invention provides an underground pipe column detection method and system and a medium, and the underground pipe column detection system comprises detection equipment, an excitation signal generator and an underground detection device; the detection equipment is in communication connection with the excitation signal generator and the underground detection device; the underground detection device comprises a transmitting coil and a magnetic sensor array consisting of a plurality of receiving coils; the excitation signal generator is configured to apply transient excitation current to the transmitting coil; the transient excitation current enables the transmitting coil to generate an excitation magnetic field; the excitation magnetic field enables the sleeve layer to generate an induced magnetic field; the magnetic sensor array is configured to collect the magnetic field intensity of the induced magnetic field and generate a magnetic field intensity vector; the detection equipment is configured to perform sparse reconstruction solution on the target vector containing the wall thickness information of the casing layer according to the magnetic field intensity vector and the space observation matrix corresponding to the magnetic sensor array, and through the embodiment of the invention, the limitation of the number of array elements on the detection resolution can be broken through, and the detection precision of the wall thickness of the underground pipe column is improved.

The invention provides a grid-connected system and method based on parallel operation power equalization of synchronous motor units, and relates to the technical field of new energy and electric power engineering. The system comprises a new energy station power generation system and a parallel synchronous motor unit group, wherein the parallel synchronous motor unit group at least comprises two synchronous motor units which have the same electrical parameters and are connected in parallel; the first end of the parallel synchronous motor unit group is connected with the new energy station power generation system, and the second end is connected with the power grid. The method comprises the following steps: connecting one ends of all synchronous motor units to the same power supply bus, applying excitation current to the motor at the end, applying excitation current to the motor at the other end, then measuring the generator end voltage waveform, adjusting the relative mechanical angles of the synchronous motor units according to the measurement result, and ensuring that the relative mechanical angles of all the motor units are equal. And power equalization between parallel synchronous motor units is realized. The system structure can be simplified, the cost can be reduced, and the reliability and the flexibility of the new energy grid-connected system can be improved.

The utility model discloses a soft start system based on excitation current reduction, which is characterized in that a time relay mainly controls the switching of a live wire between a power resistor and an alternating current contactor, the power resistor magnetizes a transformer at the moment of electrification, and the alternating current contactor is connected into a circuit by the time relay after the magnetization is completed; and after the power resistor is short-circuited, the circuit is cut out, so that the purpose of suppressing the excitation inrush current is finally achieved, the excitation effect caused by voltage abrupt change at the power-on moment of the isolation transformer can be avoided, and the excitation abrupt change of the isolation transformer during power-on is effectively reduced.

The invention provides an argon arc welding tungsten electrode appearance defect detection method and system and a storage medium, and relates to the technical field of tungsten electrode appearance detection.The method comprises the steps that firstly, a sample electrode with known defects is subjected to three-dimensional scanning and discretization into a plurality of space points, and each point is endowed with a defect existence mark; by applying a composite sine wave excitation current, an eddy current signal generated when a collector spirally passes through a detection coil at a constant speed is acquired, and laser ultrasonic scanning is synchronously utilized to acquire full-matrix data and reconstruct a three-dimensional gray model. And constructing a double-branch deep learning model, fusing the eddy current feature vector and the ultrasonic image block feature, and learning a mapping relationship between the eddy current feature vector and the defect mark. And performing the same detection on a to-be-detected electrode, outputting the defect confidence of each position by using the trained model, calculating a comprehensive quality index in combination with a preset defect severity weight and a spatial key region weight, and judging whether the electrode is qualified or not according to a qualified threshold value. According to the invention, high-precision, automatic and comprehensive detection of surface and internal defects is realized.

The invention discloses an intelligent start-stop control method and system for a magnetic suspension refrigeration compressor, and the method comprises the steps: obtaining a position perception enhancement source through collecting and analyzing the current response data of a magnetic bearing coil, and extracting the current response change characteristics; rotor position estimation is carried out based on current response change characteristics, a positioning precision driving source is extracted from estimation deviation, and a non-impact starting excitation current instruction is generated; a multi-sensor fusion data network is established, configuration is reconstructed through an abnormal response activation signal, and a degradation operation fault-tolerant mode is formed; converting a response preparation gain according to the shutdown instruction signal, performing shutdown state evaluation in combination with signal reconstruction configuration, and generating an emergency shutdown trigger condition; and the power supply state of a bus capacitor is detected, gradient control potential is released, the active damping control opportunity is determined, a damping force control instruction is generated, finally intelligent start-stop control over the magnetic suspension refrigeration compressor is achieved, and safe and reliable operation of the system under various working conditions is ensured.

The invention belongs to the technical field of magnetic suspension motors, and discloses magnetic suspension fan motor winding temperature monitoring equipment and an early warning method. The method comprises the following steps: laminating a preset temperature-sensitive ferromagnetic material and a magnetic suspension fan motor stator iron core according to a preset process to obtain a composite iron core; deploying a high-frequency excitation system on the composite iron core, adjusting the number of turns of a micro-coil of the high-frequency excitation system according to the target magnetic field intensity, collecting real-time excitation current, and analyzing to obtain magnetic induction intensity; analyzing the magnetic induction intensity through multi-physics field coupling iteration to obtain a winding three-dimensional temperature field; performing temperature gradient analysis on the three-dimensional temperature field, performing temperature early warning according to an analysis result, and dynamically adjusting motor operation parameters; according to the invention, the comprehensiveness of temperature monitoring of the magnetic suspension fan motor winding, the timeliness of early warning and the accuracy of cooling control are effectively improved, and safe and stable operation of the motor under complex working conditions is guaranteed.

The invention discloses an energy-saving control method for a new-energy high-low-voltage direct-current relay. The energy-saving control method comprises the steps of analyzing a mapping relation between a silicon steel sheet stacking angle and a magnetic flux path deviation, calculating magnetic domain wall moving resistance according to magnetic domain boundary stress, determining a magnetic domain overturning speed by combining a magnetic field change rate, and measuring a hysteresis loop width parameter. Adjusting the width and frequency of the excitation current pulse according to the magnetic domain overturning frequency and the hysteresis loop offset and width to obtain an optimized excitation current pulse sequence, and determining the hysteresis loop expansion speed according to the hysteresis loop area change rate; the local high-temperature area temperature is analyzed through the iron core temperature rise rate, the local high-temperature area distribution and the magnetic domain energy dissipation data, if the local high-temperature area temperature exceeds the preset threshold value, the excitation current pulse is adjusted, stable iron core temperature rise control data is obtained, the coercive force change amplitude is determined, the magnetic hysteresis loss and the temperature rise are reduced, the stability of the relay under high-frequency switching is improved, and the reliability of the relay is improved. And the operation efficiency and reliability of the system are greatly improved.

The invention relates to the technical field of geophysical exploration, in particular to a borehole three-dimensional observation system based on seismic-electric combined exploration. The system comprises an excitation device which is deployed in an underground drill hole and is used for respectively exciting a seismic wave signal at the same excitation point and supplying excitation current to the underground; the receiving device comprises a series of ground receiving modules arranged on the ground and an in-well receiving module arranged in at least one receiving drill hole; both the ground receiving module and the in-well receiving module are integrated with seismic wave signal receiving units and potential signal receiving units and are used for synchronously receiving seismic wave signals generated by excitation of the excitation device and potential signals in an electric field established by excitation current; and the data processing device is in communication connection with the receiving device and is configured to receive the seismic wave signal and the potential signal and determine the wave velocity parameter and the resistivity parameter of the underground target body according to the seismic wave signal and the potential signal.

The invention relates to a grounding grid fault diagnosis method and system based on an EVO-MNR algorithm, and the method comprises the steps: obtaining all accessible nodes based on a grounding grid topological structure, randomly selecting two accessible nodes, injecting an excitation current source into a grounding grid in turn, measuring and calculating the voltages of other accessible nodes, and obtaining a measurement value and a calculation value; taking the residual error of the measured value and the calculated value as a target function, and solving a first optimal solution of the grounding grid branch resistance by using an EVO algorithm; obtaining corresponding resistance value distribution based on the first optimal solution, and solving a corresponding calculation value based on the distribution; a target function value is calculated based on the corresponding calculation value, if the calculated target function value is smaller than a preset value, the first optimal solution is the optimal solution, otherwise, the target function is improved by using an MNR method to obtain an improved target function, and the optimal solution of the grounding grid branch resistance is solved based on the improved target function; and determining a fault branch based on the optimal solution. Compared with the prior art, the grounding grid fault can be quickly and accurately diagnosed.

The embodiment of the invention discloses a multiplex type three-stage starting power generation controller, and relates to the technical field of aviation three-stage starting power generators. In the starting stage, an H-bridge inverter in the starting power generation controller provides single-phase alternating-current exciting current for a main exciter stator exciting winding through SPWM modulation so as to establish a pulsating magnetic field to provide exciting current for a main motor, and a three-phase full-bridge inverter provides armature current for a main motor stator armature winding through SVPWM modulation. In a power generation stage, an anti-parallel diode of the three-phase full-bridge inverter is used as a rectification circuit of the auxiliary exciter, and the H-bridge inverter adopts a PWM chopping mode to operate as an asymmetric half-bridge circuit. A power generation controller and a starting controller are integrated into a whole, and by changing the modulation mode of a hardware circuit, the control function of the three-stage starting generator at different stages can be realized by only one controller, so that the structure of the starting power generation controller is simplified, the system integration degree of the three-stage starting generator is improved, and the volume and the weight of the system are reduced.

The invention discloses a synchronous motor modular excitation active vibration suppression method for eccentric vibration, and the method comprises the steps: dividing a rotor excitation winding into 2P independent current control excitation modules in the circumferential direction, and respectively arranging an X-direction displacement probe and a Y-direction displacement probe, obtaining a first displacement signal and a second displacement signal of the rotor mass center relative to the stator and a rotor mechanical angular speed; performing band-pass filtering on the first displacement signal and the second displacement signal, and extracting a first displacement first-order component and a second displacement first-order component; calculating the shortest air gap direction angle and the eccentricity amplitude under the stator coordinate system, calculating the eccentricity, and calculating a first-order eccentricity coefficient; calculating a shortest air gap direction angle under a rotor coordinate system, and calculating an equivalent correction coefficient; and according to the equivalent correction coefficient, the first-order eccentricity coefficient, and the shortest air gap direction angle and the mechanical position angle under the rotor coordinate system, the injection amount of each excitation module is calculated, an excitation current instruction is generated and output to the corresponding excitation module, and active suppression of the unbalanced magnetic pulling force is realized.

The invention discloses a flexible phased-array antenna sensing regulation and control method and system based on array element mutual coupling, and mainly solves the problem of electrical performance deterioration caused by structural deformation of a phased-array antenna. Comprising the following steps: 1) acquiring strain information of a phased-array antenna in real time by using a fiber grating strain sensor; 2) constructing an electromagnetic calculation model considering mutual coupling, and calculating radiation characteristics of an antenna array through an array superposition principle; 3) building a neural network framework KAN, setting an input layer as a strain, and setting an output layer as an amplitude and phase adjustment amount; 4) constructing a physical information neural network by using the neural network output layer and the electromagnetic calculation model, and training the physical information neural network; 5) inputting the strain into the trained model, calculating the amplitude and the phase adjustment amount of the excitation current of the antenna unit, and sending the amplitude and the phase adjustment amount to a wave control circuit; and 6) adjusting each antenna unit by using the T / R assembly to realize regulation and control. According to the invention, the self-adaptive compensation of the phased-array antenna in service can be realized, and the regulation and control precision is effectively improved.

The invention discloses a measurement method for accelerated calorimeter test based on in-situ electrochemical impedance spectroscopy. The measurement method comprises the following steps: applying excitation current to a battery to be detected; measuring the battery to be detected under the current condition through the EIS module to obtain real part impedance and imaginary part impedance under different frequencies; determining phase angles and impedances under different frequencies according to the real part impedances and the imaginary part impedances under different frequencies; the voltage of the battery to be detected at different surface temperatures is collected through the ARC module, and the corresponding temperature rise rate is determined; determining an impedance modulus deviation, a phase deviation, a voltage sharp change deviation and a temperature rise rate deviation according to the phase angles and the impedances under the different frequencies, the voltages under the different surface temperatures and the corresponding temperature rise rates, and generating an error signal; generating a corresponding sampling rate control instruction according to the error signal based on dynamic PID control; and the ARC module adjusts the sampling frequency according to the sampling rate control instruction so as to perform high-precision measurement.

The invention relates to the technical field of fault prediction, and discloses an excitation online monitoring system, which comprises an information acquisition module, a data processing module, a mechanical wear quantification module, a shaft vibration health analysis module, a feature fusion module, a mechanical health analysis module and an early warning instruction generation module, collecting multi-source operation data in the gas generator set in real time; performing time-frequency domain conjoint analysis on the excitation current waveform to obtain a current high-frequency ripple component; carrying out harmonic distortion rate fusion on the current high-frequency ripple component to obtain a current ripple characteristic coefficient; dynamically correcting a preset rotor vibration threshold value, and comparing the rotor shaft vibration signal with the dynamically corrected rotor vibration threshold value to obtain a shaft vibration health index; performing cross-domain feature fusion to obtain fused features; carrying out the normalization processing of the fusion features, obtaining a comprehensive health state score, and generating a PHM early warning instruction of a fault block in the excitation primitive; according to the invention, the excitation monitoring accuracy of the gas generator set can be improved.

The invention relates to the technical field of antennas, and provides an antenna, a communication method and terminal equipment, and the method comprises the steps: attaching a metal floor to a first surface of a dielectric substrate; the first excitation element and the second excitation element are respectively arranged on the first side and the second side of the metal floor, and the sizes of the two elements are related to a target frequency band; an inner conductor and an outer conductor of the first feed assembly are correspondingly connected with a first feed point of the first excitation element and the metal floor respectively; an inner conductor and an outer conductor of the second feed assembly are correspondingly connected with a second feed point of the second excitation element and the metal floor respectively; the first feed assembly is used for providing first excitation current for the first excitation element; the second feed assembly is used for providing a second excitation current for the second excitation element; the first excitation current and the second excitation current with different phase differences can present different current distributions on the metal floor, so that the purpose of antenna radiation beam steering is achieved, the technical effect of wide beams is achieved, and thus space direction coverage on a target frequency band is achieved.

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 relates to a grounding grid corrosion fault diagnosis method and system based on an improved SABO, and the method comprises the steps: obtaining all accessible nodes based on a grounding grid topological structure, injecting excitation current into a grounding grid in a multi-rotation excitation mode, and obtaining a measurement value of a node voltage and an initial value of a branch resistor; taking the change multiple of the branch resistance value relative to the branch resistance initial value as a to-be-solved variable, constructing a fitness function based on a measured value and a calculated value, and solving by using an improved SABO algorithm based on dynamic differential variation to obtain an optimal value of the change multiple of each branch; and judging whether the branch corresponding to the optimal value has a corrosion fault or not based on the optimal value. Compared with the prior art, the fault area in the grounding grid can be identified more accurately and efficiently.

The invention discloses a rotor turn-to-turn short circuit diagnosis method based on an exciting current-shaft voltage harmonic nonlinear correlation coefficient. The method comprises the following steps: synchronously collecting parameters, and preprocessing the collected parameters through wavelet threshold denoising and temperature normalization; extracting harmonic analysis according to the shaft voltage harmonic characteristics; identifying magnetic saturation, temperature and load nonlinear factors and calculating corresponding coefficients; performing dynamic correction on the Pearson's correlation coefficient through the nonlinear correction coefficient, and combining with fuzzy logic weighting to obtain fuzzy logic weighting; defining a working condition feature vector, and constructing a working condition adaptive dynamic model comprising a linear regression basic model and an LSTM neural network; and calculating a dynamic threshold value based on the basic threshold value and the nonlinear factor, and judging the turn-to-turn short circuit trend of the rotor according to the comparison of the correlation coefficient and the dynamic threshold value and a prediction result. According to the invention, through combination of the nonlinear correction correlation coefficient and the LSTM neural network, dynamic compensation of nonlinear factors is realized, and the accuracy and reliability of rotor turn-to-turn short circuit fault diagnosis are improved.

This application provides a bioelectrical impedance measurement method, circuit, chip, and electronic device. The method includes: obtaining a first contact impedance value corresponding to a first excitation electrode and a second contact impedance value corresponding to a second excitation electrode through a preset method; determining the transmission direction of an excitation current between the first and second excitation electrodes based on the first and second contact impedance values; controlling the excitation current to transmit between the first and second excitation electrodes according to the transmission direction; determining a target voltage value between a first and second measuring electrode, and calculating the impedance of the measured object based on the target voltage value; wherein the first and second contact impedance values ​​are different. This application can reduce the influence of contact impedance on the bioelectrical impedance measurement results, reduce the measurement error of bioelectrical impedance, and improve the accuracy of bioelectrical impedance measurement.

A method for manufacturing an electrically excited rotor is described. The method comprises providing a rotor body with electrically conductive windings and potting the rotor body with a potting compound, such that an electrically conductive winding interface remains accessible. Furthermore, following the potting, the method includes connecting the winding interface to an electrical power supply to provide an excitation current for the windings.