14 results about "Transfer impedance" patented technology

The application provides a transient ground potential rise induced coupling determination method through cable shielding layer, and belongs to the technical field of cable shielding layer.The application establishes a distributed parameter partial element equivalent circuit model of a grounding network, solves transient ground potential distribution by using a finite difference time domain method, obtains equivalent transfer impedance frequency characteristics of a braided shielding layer by using a four-port S parameter vector network analysis method and a variational asymptotic homogenization multi-scale algorithm, solves core line common mode voltage and differential mode voltage by establishing a multi-conductor transmission line equation group, constructs an artificial intelligence prediction model based on a topology perception graph neural network, solves a large-scale sparse admittance matrix by using a multilevel fast multipole method to obtain full network induced voltage distribution, and establishes a quantitative relationship model between ground potential rise and core line induced voltage, so that the technical problems that cable core line induced voltage caused by transient ground potential rise is difficult to accurately predict and effectively suppress are solved.

This invention discloses a multi-harmonic source responsibility quantification method based on asynchronous measurement, relating to the field of power quality harmonic technology. The method includes measuring the harmonic voltage of the bus of interest and the harmonic current at the connection point between each harmonic source and the bus of interest to construct the observed signal. After centering and whitening, a covariance matrix is ​​constructed. For the covariance matrix, the optimal common orthogonal matrix is ​​determined, and the source signal matrix is ​​reconstructed. The harmonic transfer impedance corresponding to each harmonic source signal is calculated based on a fast-changing component model. Each harmonic source signal is multiplied by its corresponding harmonic transfer impedance to obtain the harmonic voltage of the corresponding harmonic source. The harmonic voltage is projected onto the harmonic voltage of the bus of interest to achieve multi-harmonic source responsibility quantification. This method does not rely on GPS, simplifying the operation steps of multi-harmonic source responsibility quantification and helping to improve quantization efficiency. Simultaneously, the sparsity of the hybrid matrix reduces the computational dimensionality, alleviating the computational burden and improving quantization accuracy.

The application discloses a kind of lithium battery charge-discharge intelligent early warning method and system, belong to computer technology field.The method includes: when battery charges and discharges, actively injects multiple-frequency ac disturbance signal;Response signal is collected and is parsed to obtain dynamic electrochemical impedance spectroscopy containing charge transfer impedance and low-frequency phase angle;Based on the preset multidimensional health impedance mapping table, the reference impedance and reference phase angle corresponding to the current temperature and state of charge are inquired;Impedance relative deviation and phase angle offset are calculated;At least based on the deviation and offset, the internal micro-short circuit of battery is identified and early warning operation is executed;Through multidimensional mapping table and dynamic threshold mechanism, effectively eliminate working condition and aging interference, with high sensitivity and low false alarm rate;And supplemented by hierarchical early warning, standing verification and multi-cell collaborative calibration, the safety and usability of battery system are significantly improved.

This invention discloses a simulation-based method and system for handling electromagnetic interference in motor controllers, belonging to the field of electromagnetic compatibility testing and simulation technology. By constructing a test environment structural model including a test bench, artificial power network, shielded cables, current probes, the motor controller body, and the motor load using an electromagnetic simulation platform, electromagnetic field simulation calculations are performed to extract structural parasitic parameters and convert them into an equivalent circuit model. The equivalent circuit model is integrated into the main circuit simulation model to form a field-circuit coupled simulation model, and preliminary conducted emission simulation results are obtained. A current probe model is established, and the transfer impedance calibration factor is calculated. The preliminary simulation results are coupled and calibrated to obtain high-precision conducted emission simulation results. Based on the calibrated simulation results, the suppression effects of different interference suppression schemes are configured and evaluated, and the optimal suppression scheme is selected. The proposed scheme significantly improves the simulation accuracy of the conducted emission current method.

The application discloses a battery lithium precipitation detection method and device. When an electrochemical impedance test is performed on a battery, a corresponding first test result can be obtained. According to the first test result, corresponding first positive electrode charge transfer impedance and first negative electrode charge transfer impedance can be determined. Then, at least according to the initial positive electrode charge transfer impedance, the initial negative electrode charge transfer impedance, the first positive electrode charge transfer impedance and the first negative electrode charge transfer impedance, whether the battery has lithium precipitation can be determined. In this way, when detecting whether the battery has lithium precipitation, the battery does not need to be disassembled, and the detection can be realized, so that nondestructive testing is realized.

The invention discloses a multi-harmonic source responsibility quantification method based on asynchronous measurement, and relates to the technical field of electric energy quality harmonics. The method comprises the following steps: measuring harmonic voltage of a concerned bus and harmonic current at a connection point of each harmonic source and the concerned bus to construct an observation signal, and constructing a covariance matrix after centralization and whitening: for the covariance matrix, determining an optimal common orthogonal matrix and reconstructing a source signal matrix; calculating harmonic transfer impedance corresponding to each harmonic source signal based on a fast-changing component model; multiplying each harmonic source signal by the corresponding harmonic transfer impedance to obtain a harmonic voltage of the corresponding harmonic source; and projecting the harmonic voltage to the harmonic voltage of the concerned bus to realize multi-harmonic source responsibility quantification. The method does not depend on a GPS, the operation steps of multi-harmonic source responsibility quantification are simplified, and the quantification efficiency can be improved; meanwhile, the calculation estimation dimension can be reduced through the sparsity of the hybrid matrix, the calculation burden is reduced, and the quantization precision is improved.

The application provides a cost allocation method and device for an AC-DC hybrid power distribution network based on a distribution factor, which comprises the following steps: constructing an equivalent model of the AC-DC hybrid power distribution network; the equivalent model is used to calculate the transfer impedance of each node of the AC-DC hybrid power distribution network to a branch; based on the equivalent model, the transfer impedance of each node to the branch is calculated, and an augmented distribution factor matrix of the AC-DC hybrid power distribution network is determined; the augmented distribution factor matrix is used to calculate the usage degree of each node of the AC-DC hybrid power distribution network to a line; based on the augmented distribution factor matrix, a cost allocation principle is determined, the cost of the AC-DC hybrid power distribution network is allocated, and an initial cost allocation result is calculated; the cost comprises a fixed cost and a variable cost; based on a generator-load power distribution matrix, the initial cost allocation result is corrected to obtain a cost allocation result. The application can improve the rationality, fairness, applicability and stability of the cost allocation of the AC-DC hybrid power distribution network.

This invention discloses a charging method based on an adjustable charging curve for battery health status perception, comprising the following steps: synchronously acquiring voltage and current responses through a micro EIS measurement circuit and obtaining the real and imaginary parts of impedance at different frequencies using Fast Fourier Transform, thereby generating an electrochemical impedance spectrum of the battery during charging and discharging; segmenting and fitting the high-frequency, mid-frequency, and low-frequency regions, extracting characteristic values ​​of ohmic internal resistance, charge transfer impedance, and diffusion impedance respectively, and generating impedance spectrum characteristic parameters; inputting the impedance spectrum characteristic parameters to a control chip to fit and estimate the battery health status assessment value, and constructing a battery health status perception model to dynamically generate an adjustable charging curve; performing a charging operation on the battery according to the adjustable charging curve, and dynamically adjusting the parameters of the adjustable charging curve, thereby achieving closed-loop adaptive adjustment of the charging process. This invention can dynamically adjust the charging curve parameters to achieve closed-loop adaptive adjustment of the charging process.

The invention relates to a single-pole grounding protection method for a complex multi-terminal flexible direct current power distribution network based on a phase space transient mapping trajectory, which is suitable for a multi-terminal flexible direct current system comprising various converters. According to the method, phase space trajectories of currents at two ends of a fault line are constructed, a delay embedded vector is constructed by using dominant frequency, trajectory directivity and main axis offset are extracted, direction criteria and form criteria are formed respectively, and dual identification of internal and external faults is realized. And by combining a virtual breaking point theory and transfer impedance modeling, the universality and accuracy of fault modeling are ensured. The method does not depend on communication and synchronization, has good high-resistance adaptability and anti-noise performance, and is suitable for engineering deployment.

This invention provides an in-situ non-destructive diagnostic method for sodium deposition during low-temperature charging of sodium-ion batteries, belonging to the field of battery diagnostic technology. In this invention, ultrasonic emission, reflection, and transmission receiving modules are arranged along the thickness direction of the battery under test, connected to an electrochemical workstation, constructing a dual-mode ultrasonic detection architecture of transmission and reflection to achieve in-situ non-destructive testing. The battery is adjusted to a fully discharged state, placed in a high-low temperature test chamber, and a room-temperature control group is set up. It is charged with a preset constant current, and AC disturbances are simultaneously applied to drive ultrasonic pulses. Cyclic testing is performed at set time intervals to achieve in-situ, continuous, and synchronous acquisition of electrochemical and ultrasonic data. Charge transfer impedance is extracted based on impedance spectroscopy, interface main echo and layered slice imaging are obtained based on ultrasonic reflection data, and a two-dimensional sound velocity distribution image is established based on ultrasonic transmission data. A multi-signal joint criterion is used to determine sodium deposition and distinguish between early and late stages, effectively improving the accuracy and flexibility of low-temperature sodium deposition diagnosis.

The invention discloses an electrostatic discharge target link transfer impedance calibration method, which belongs to the technical field of electrostatic discharge, and comprises the following steps: firstly, connecting the positive electrode of the output end of a direct current source to the input end of a metered ampere meter, and converting the output end of the ampere meter and the negative electrode of the direct current source into an N-type or SMA-type radio frequency cable to be connected with a current target adapter; after the current target adapter is aligned with the electrostatic discharge target, the screws of the through holes are tightened, so that the current target adapter is connected with the inner cores of the electrostatic discharge target, the shells are reliably connected, and the output end of the electrostatic discharge target is connected with an attenuator and then connected with an oscilloscope through a radio frequency cable. According to the calibration method, the current target adapter is connected with the current target, the current target is converted into a common radio frequency connector, the reliability of the calibration system is improved, and measurement errors caused by poor contact are reduced. By introducing the ampere meter, the input current of the input end of the current target is monitored in real time, and the influence factor of inaccurate output current caused by impedance matching is reduced.

The invention discloses a short-circuit current suppression method, device and equipment and a storage medium, and belongs to the technical field of power systems and power electronics, and the method comprises the steps: building an equivalent model of a target power grid, and carrying out the load flow calculation of the equivalent model, and obtaining an initial state; when the initial state accords with an operable state, calculating an admittance matrix based on line parameters and equipment parameters of each line in the equivalent model; the line comprises a bus and a branch line; calculating according to the admittance matrix to obtain an impedance matrix, and obtaining transfer impedance between corresponding buses according to the impedance matrix; establishing a short-circuit current sensitivity index according to the transfer impedance, and determining a target AC line based on the short-circuit current sensitivity index; and replacing the target alternating-current line with a flexible direct-current transmission line so as to suppress the short-circuit current. Therefore, by implementing the method, the problem of low stability caused by non-uniform power flow distribution on the line in the prior art can be solved.

The invention proposes a power distribution system voltage sag estimation method based on a system impedance matrix, and relates to the technical field of power distribution networks, and the method comprises the steps: S1, defining a voltage sag correlation region based on the transfer impedance correlation of the impedance matrix of a power distribution system, and determining the position of an optimal power quality monitoring point; s2, acquiring a transfer impedance sum ratio of a monitoring node to a non-monitoring node based on the position of the optimal power quality monitoring point, and establishing a linear correlation model of the indexes; s3, analyzing the influence of the number of monitoring points on the voltage sag estimation precision of the power distribution system through multi-scene simulation according to the linear correlation model of the indexes; s4, verifying in an IEEE24 node system network according to an analysis result, and outputting a power distribution system voltage sag estimation result passing verification; the method can directly reflect the physical mechanism of the voltage sag of the power distribution system, avoids the problem of separation from the actual operation characteristics of the power distribution system caused by pure mathematical fitting in the existing method, and is adaptive to the engineering application scene of the power distribution system.

The invention discloses an intelligent detector for tomography and material recognition. The intelligent detector comprises a shell and a sensor module in the shell. The signal processing module comprises an analog switch matrix, a multi-frequency excitation signal generation unit and a response signal acquisition unit; the calculation control module is used for controlling the channel switching of the analog switch matrix, the generation of a multi-frequency excitation signal and the acquisition of a response signal, and processing the obtained transfer impedance data; the interface module receives an input instruction of a user and transmits the input instruction to the calculation control module; and outputting an image and a material identification result obtained by processing of the calculation control module. Therefore, through the technical means of applying multi-frequency current, measuring the electrical impedance distribution of an object under different frequencies and further identifying the material type according to the difference of the electrical impedance characteristics of different materials, uniform detection response is achieved to eliminate the end effect, high-precision material type identification is achieved, and wood, metal, PVC and other materials are accurately distinguished.