10 results about "Equivalent circuit analysis" patented technology

The invention discloses a fault ride-through test method for an offshore wind power flexible direct output system, and the method comprises the steps: building a fault equivalent circuit of the offshore wind power flexible direct output system, analyzing the operation characteristics of an AC power grid side under a low-voltage fault, and determining the incidence relation between the DC side excess energy and the power grid voltage drop; establishing a model representing each component in the fault equivalent circuit, wherein the components at least comprise a machine-side converter, a grid-side converter, a direct-current capacitor and an unloading resistor; when a low-voltage fault of an alternating-current power grid side is detected, executing the following cooperative control based on the model: synchronously starting unloading resistance control and reactive power support control, wherein an unloading resistor dissipates excess energy of a direct-current side through a direct-current chopper; the grid-side converter injects a capacitive reactive current which is deeply matched with the voltage drop of the power grid so as to improve the voltage of a grid-connected point; and if the direct-current voltage continuously exceeds the preset threshold value, starting power prompt drop control, and reducing the output power of the unit according to a gradient until the system recovers to be stable.

The invention belongs to the technical field of energy storage batteries, and discloses an energy storage battery state evaluation method based on a generated impedance spectrum and a related device. The method comprises the following steps: acquiring impedance data of a to-be-evaluated energy storage battery; equivalent circuit fitting is carried out based on the impedance data of the energy storage battery to be evaluated, and equivalent element parameters are obtained; the correlation degree between the equivalent element parameters and the battery health state is calculated, and parameters with the correlation degree larger than a threshold value are selected as characteristic parameters; and inputting the characteristic parameters into a pre-established energy storage battery SOH evaluation model based on the generative impedance spectroscopy to obtain the health state of the energy storage battery to be evaluated. According to the invention, the test speed of the AC impedance spectroscopy and the interpretability of the evaluation model are considered; a full-spectrum alternating-current impedance spectrum is generated by using an adversarial neural network through a few points in different frequency ranges, so that the problems that full-spectrum testing time is long and engineering application is not facilitated are solved; and performing equivalent circuit analysis by using the generated full spectrum, and performing health state evaluation of the energy storage battery.

The invention provides an equivalent circuit analysis method and system for soil resistance heating efficiency, and relates to the technical field of soil remediation. Resistivity distribution data and salt content distribution data of a pile space are obtained; calculating the ionic conductivity according to the salt content distribution data, and calculating the target conductivity of each grid unit; constructing a topological graph, and constructing a weighted adjacent matrix based on the topological graph; constructing a degree matrix according to the degree of each graph node to obtain a feature value sequence and a feature vector corresponding to each feature value; extracting a second small feature value from the feature value sequence as a connectivity index, and marking a mutation position as a weak connection interface; the blocking factor is determined by counting the number of graph nodes located at the weak connection interface, the equivalent circuit transmission efficiency representing the soil resistance heating efficiency is calculated based on the negative correlation between the connectivity index and the blocking factor, and accurate quantitative evaluation of the heterogeneous soil resistance heating efficiency is achieved.

This invention discloses a simulation method, apparatus, equipment, and medium for an electromagnetic railgun. Compared to constant load parameter values, it employs a finite element method combined with equivalent circuit analysis. The rail is divided into N segments, and the armature is positioned at the end of the i-th segment. The current equivalent load parameters of the rail are updated based on the circuit parameters at each discrete time point, thereby approximating the true value of the equivalent load parameters segment by segment. The current equivalent load parameters are then substituted into the circuit and mechanical equations to calculate the discrete data when the armature is positioned at the end of the i-th segment. If i < N, let i = i + 1, and iterate the above simulation steps; if i = N, then fit all the calculated discrete data between the armature velocity and discrete time points to obtain continuous data between the armature velocity and time. It is evident that this invention corrects the equivalent load parameters whenever the armature moves a certain distance, thus simulating an electromagnetic railgun firing process that more closely approximates the real situation.

The invention discloses an electrostatic sensitivity test method and device based on CDM discharge simulation, and belongs to the technical field of electrostatic measurement, the method is realized based on a test system, and the test system comprises a tested module, which comprises a charging panel capable of switching charging and discharging states and a tested device on the charging panel; the discharge waveform acquisition module comprises a test probe of which one end is grounded, a visual unit and a driving unit; the visual unit is used for acquiring relative position information of the test probe and the tested device; the driving unit is used for driving the test probe to move; when the tested device is in an electrostatic energy storage state, the control module controls the driving unit to drive the other end of the test probe to contact with the tested device according to the relative position information; the test method comprises the following steps: a test probe is in contact with a tested device to obtain a CDM discharge waveform; and equivalent circuit analysis is carried out on the test system to obtain influence parameters of the CDM discharge current, so that high-precision and automatic static sensitivity test is realized.

The application relates to the technical field of light-adjusting liquid crystal film production, and provides a light-adjusting liquid crystal film partition line cutting abnormality detection method and system, which places the to-be-detected light-adjusting film in a detection environment with constant temperature and humidity, analyzes an equivalent circuit of the film sheet, detects parallel internal resistance of the corresponding equivalent circuit, precontrol environment conditions to reduce the influence of environment changes on the detection resistance value, and the detection precision of the internal resistance is improved; the internal resistance of the partition line area is comprehensively analyzed according to the detection, different states of the partition line cutting are judged according to different detection results, long-time power-on detection is not needed, the cutting state detection of the entire light-adjusting film partition line can be quickly realized, the detection efficiency is high, the detection accuracy can be improved through the set judgment condition, and the detection precision is ensured.

The application discloses a rotor voltage compensation method for a doubly-fed wind turbine based on rotor transient current, and the method comprises the following steps: step 1, during the low-voltage ride-through of the doubly-fed wind turbine, short-circuit fault analysis is carried out on the doubly-fed induction generator (DFIG) in different rotating coordinate systems; step 2, the rotor current composition and the equivalent circuit of the rotor winding in each coordinate system are obtained, and the equation relationship between the rotor current compositions in different coordinate systems is analyzed; and step 3, the steady-state rotor current and the transient-state rotor current in the rotor current are separated through the Park transformation, the compensation value of the rotor voltage is obtained by combining the transient-state rotor current and the rotor winding loop, the increase of the rotor current is inhibited, and the influence of the compensated rotor voltage on the stator flux decay is considered; the compensation value of the rotor voltage which needs to be compensated in the dq rotating coordinate system is obtained through the rotor winding loop in the transient process, so that the rotor current is controlled within the safety threshold, and the low-voltage ride-through range of the doubly-fed wind turbine is expanded.

A state measuring device includes an electrode that applies an alternating current signal to a mixed solution; a measurement unit that measures an impedance of the mixed solution for each frequency of the alternating current signal based on a response signal flowing in the mixed solution when the alternating current signal is applied; a setting unit that sets an equivalent circuit including one or more parallel circuits based on an element corresponding to an electrical component of a solid substance; a calculation unit that performs equivalent circuit analysis for approximating the impedance of the equivalent circuit to the impedance of the mixed solution to calculate parameters of the parallel circuits; and an inference unit that infers an index for determining a state of the mixed solution based on the parameters of the parallel circuits.

The application provides a soil resistance heating efficiency equivalent circuit analysis method and system, relates to the soil remediation technical field, and obtains the resistivity distribution data and the salt content distribution data of the heap space; calculates the ion conductivity according to the salt content distribution data, calculates the target conductivity of each grid unit; constructs a topology graph, and constructs a weighted adjacency matrix based on the topology graph; construct a degree matrix according to the degree of each graph node, obtain an eigenvalue sequence and a characteristic vector corresponding to each eigenvalue; extract the second smallest eigenvalue from the eigenvalue sequence as a connectivity index, and mark the mutation position as a weak connection interface; determine the blocking factor by counting the number of graph nodes located at the weak connection interface, calculate the equivalent circuit transmission efficiency representing the soil resistance heating efficiency based on the negative correlation between the connectivity index and the blocking factor, and realize accurate quantitative evaluation of the heterogeneous soil resistance heating efficiency.

Provided is a magnetostrictive member having a high parallel magnetostriction amount and a small variation in the parallel magnetostriction amount between members, the magnetostrictive member having a high device output and suppressed variation in the optimal magnetic field strength in device characteristics when assembled in a magnetostrictive vibration power generation device. A plurality of magnetostrictive members are obtained from the same crystal, each magnetostrictive member is composed of a crystal of an iron-based alloy having magnetostrictive characteristics, and is a plate-shaped body having a long-side direction and a short-side direction, and the front surface and / or the back surface of the plate-shaped body has a plurality of grooves extending in the long-side direction. The ratio (standard deviation / average value) of the standard deviation of the optimal magnetic field strength obtained by electromechanical equivalent circuit analysis of the plurality of magnetostrictive members to the average value of the optimal magnetic field strength is 0.2 or less.