28 results about "Nyquist plot" patented technology

Disclosed in the present invention are a method and system for small-signal stability analysis of a power plant containing grid-forming converters. The method comprises: establishing a grid-following converter impedance model; establishing a grid-forming converter impedance model; constructing a new energy power plant grid-connected system model containing grid-following converters and grid-forming converters; establishing a simplified equivalent circuit of a power plant grid-connected system; establishing a small-signal stability Nyquist criterion for a grid-connected new energy power plant containing grid-forming converters; and using a Nyquist plot to analyze the small-signal stability characteristics of the power plant grid-connected system. According to the present invention, the problem in the prior art of lacking quantitative and effective analysis of small-signal stability in new energy power plants containing grid-following converters and grid-forming converters is solved, and establishing a small-signal stability criterion for the power plants on the basis of established small-signal models enables quantitative analysis of the small-signal stability characteristics of a new energy power plant containing grid-forming converters under low grid strength conditions, and compared with conventional impedance modeling methods for new energy power plants, the impact of grid-forming converter integration on the small-signal stability of the new energy power plants is better reflected.

The invention discloses a full-band cooperative oscillation suppression method for a heterogeneous inverter series-parallel system. Establishing an equivalent impedance model without introducing a cooperative oscillation suppression strategy, constructing a following network type medium-high frequency stability enhancement controller, setting parameters of the following network type medium-high frequency stability enhancement controller, constructing a construction network type damping dynamic coordination controller, selecting parameters of the construction network type damping dynamic coordination controller, and performing dynamic coordination control on the construction network type damping dynamic coordination controller. And establishing an equivalent impedance model to which the collaborative oscillation suppression strategy is introduced, comparing the Bode diagram and the Nyquist diagram of the impedance model to which the collaborative oscillation suppression strategy is not introduced and the impedance model to which the collaborative oscillation suppression strategy is introduced, and verifying the correctness of theoretical analysis and the effectiveness of the proposed suppression strategy. The risk of oscillation of the system in the full frequency band is reduced, and the stability of the system in the full frequency band is enhanced.

The invention relates to the technical field of power systems, and discloses a multi-level direct current sending end small disturbance stability assessment method, device and equipment and a medium. Carrying out frequency domain impedance modeling on the following network type new energy converter, the constructed network type energy storage converter, the following network type load converter and the modularized multi-level high-voltage direct current converter station, and constructing a frequency domain impedance network of the all-electric system based on an equivalent impedance model of each device; and performing small disturbance stability analysis on the frequency domain impedance network by using a generalized Nyquist stability criterion, and determining the small disturbance stability of the all-electric system in an alternating current and direct current hybrid scene through a Nyquist diagram of impedance ratios of two sides of a voltage source and a current source in the frequency domain impedance network. Therefore, an effective evaluation means is provided for stable operation of the alternating-current and direct-current series-parallel all-electric system.

The invention discloses a battery diagnosis method based on an electrochemical impedance spectroscopy, and the method comprises the following steps: 1, applying a disturbance current to a target battery, and collecting an AC voltage generated by the disturbance current; step 2, an impedance parameter is calculated based on a digital phase-locked amplification algorithm, and the calculation of the impedance parameter meets the following conditions: impedance, alternating voltage processed by a digital phase-locked amplifier and disturbance current; step 3, constructing an EIS fingerprint of the target battery, wherein the EIS fingerprint is generated based on the Nyquist diagram feature of the impedance parameter; and 4, evaluating the state of the target battery by using the EIS fingerprint, wherein the state comprises a state of charge, a state of health and a fault risk. The method evaluates the state of charge and the state of health of the battery based on the EIS fingerprint, and has the advantage of accurate evaluation result.

Disclosed herein is a method and system for analyzing wellbore fluid samples using impedance spectroscopy to identify chemical constituents and detect contaminants. The approach involves collecting fluid samples from a wellbore and performing chemical impedance spectroscopy by applying multiple discrete frequencies of alternating current, generating impedance spectra that are transformed into Nyquist and Bode plots for analysis. A data processing workflow handles raw impedance data through steps of labeling, cleaning incomplete sweeps, temperature thresholding, and temperature compensation to a reference standard. A hybrid modeling approach that integrates physics-based modeling (using a modified Randles circuit) with advanced data analytics techniques (utilizing Gaussian Process Regression) is utilized. Derived electrical properties, particularly susceptance and permittivity, are used to enhance the predictive capabilities of the model. This enables quantitative measurement of contaminants including mud filtrate and various salt types in wellbore fluids.

The purpose of the present invention is to provide a technique capable of accurately and quickly diagnosing the state of a battery without pre-storing measurement data. This battery diagnostic device determines a first frequency at which a component caused by diffusion resistance of an equivalent circuit of a battery begins to appear in a Nyquist map of the battery, and determines a second frequency at which a phase of the voltage and a phase of the current coincide with each other in phase frequency characteristics of the voltage and the current. The state of the battery is diagnosed using a real part of each of the first impedance of the battery at the first frequency and the second impedance of the battery at the second frequency (fig. 8).

To provide an electrochromic sheet, a laminate, a lens for spectacles, and spectacles capable of rapid color development. [Solution] An EC sheet comprising a first substrate, a second substrate, an EC element, and a sealing portion, wherein the EC element has a first transparent electrode, a second transparent electrode, and an EC layer, and the visible light transmittance of the EC sheet changes within a range including 30% upon application of a voltage, and the impedance of the EC sheet is measured under the following measurement conditions, and the internal resistance per unit area calculated from the obtained Nyquist diagram using the following formula (1) is 250 Ω / cm. 2 Below is the electrochromic sheet. Internal resistance = Resistor 1 + (Resistor 2 - Resistor 1) x 2…(1) (Resistance 1 is the value at the intersection of the horizontal axis of the Nyquist diagram and the graph of the Nyquist diagram. Resistor 2 is the real component of the point where the imaginary component of the graph is maximum in the low frequency region of the graph)

Providing electrochromic sheets, laminates, eyeglass lenses, and eyeglasses that enable rapid color development. [Solution] An EC sheet comprising a first substrate, a second substrate, an EC element, and a sealing portion, wherein the EC element has a first transparent electrode, a second transparent electrode, and an EC layer, and the visible light transmittance of the EC sheet changes within a range including 30% when a voltage is applied, and the impedance of the EC sheet is measured under the following measurement conditions, and the internal resistance per unit area obtained from the obtained Nyquist diagram using the following formula (1) is 250 Ω / cm². 2 The following is an electrochromic sheet. Internal resistance = Resistance 1 + (Resistance 2 - Resistance 1) × 2 ... (1) (Resistance 1 is the value at the intersection of the horizontal axis of the Nyquist plot and the graph of the Nyquist plot.) Resistor 2 is the real component of the point where the imaginary component of the graph is maximized in the low-frequency region of the graph.

The present invention uses the absolute value |Z| of impedance Z extracted at frequencies lower than or equal to the frequency at the apex of a semicircle (Nyquist plot) in the GEIS method or the PEIS method and evaluates the corrosion resistance of a constituent material of a working electrode of interest on the basis of the change over time in the absolute value |Z|.

The present application relates to the technical field of power system, discloses a kind of multi-level DC sending end small signal stability evaluation method, device, equipment and medium, the present application considers the coupling influence between different heterogeneous devices, to network type new energy converter, network type energy storage converter, network type load converter and modular multi-level high voltage direct current converter station are carried out frequency domain impedance modeling, and based on the equivalent impedance model of each device, the frequency domain impedance network of all-electric system is constructed, the small signal stability of frequency domain impedance network is analyzed using generalized Nyquist stability criterion, the Nyquist diagram of impedance ratio on the two sides of voltage source and current source in frequency domain impedance network is determined The small signal stability of all-electric system under AC / DC hybrid scene, so as to provide an effective evaluation means for the stable operation of AC / DC hybrid all-electric system.

To provide an electrochemical impedance analyzer capable of addressing a case where each circular arc of Nyquist diagram indicated by EIS data of a measured battery may include a plurality of reaction resistance components and highly accurately deriving an equivalent circuit from the EIS data.SOLUTION: An electrochemical impedance analyzer 10 comprises a storage part 14 storing a material property database 14a including material feature quantity data, an acquisition part 12a acquiring EIS data, and an analysis part 12b deriving the equivalent circuit. The analysis part 12b identifies time constant of each of a first reaction resistance component and a plurality of second reaction resistance components by reference to the material property database 14a when one first reaction resistance component composing the equivalent circuit is determined to be composed by parallel connection of the plurality of second reaction resistance components, and derives the equivalent circuit by performing fitting processing using the identified time constant.SELECTED DRAWING: Figure 1

This invention relates to the field of fuel cell technology and discloses a fuel cell impedance attribution method based on a physically interpretable impedance model. The method includes: performing impedance decomposition on the physically interpretable impedance model to obtain multiple sub-impedances of the fuel cell, including ohmic resistance, anode impedance, cathode activation impedance, cathode mass transfer diffusion impedance, and cathode mass transfer convection impedance; obtaining the frequency corresponding to the minimum value of the imaginary part of each sub-impedance, the inverse of the minimum value of the imaginary part, and the difference between the low-frequency real part value and the high-frequency real part value, as characteristic frequencies, imaginary peak values, and equivalent resistances; plotting the Nyquist plot, Bode plot, resistance ratio of the sub-impedance's equivalent resistance to the total equivalent resistance, and frequency-peak plot reflecting the relationship between the characteristic frequency and the imaginary peak value for each sub-impedance, to determine the contribution of each sub-impedance to the physically interpretable impedance model, thus realizing impedance attribution analysis under the physically interpretable impedance model.

The present invention relates to a method for the optimized simulation of a characteristic of a battery cell, containing a method for determining a varying internal resistance (RG) of a battery cell, in which method an electrochemical impedance spectroscopy is measured on the battery cell and an internal resistance (RG) of the battery cell is determined from a difference between a value of the locus curve with respect to a high-frequency measurement point (MPH) and a value of the locus curve with respect to a low-frequency measurement point (MPN) on the real-value axis (RE) of the Nyquist plot. In the further steps, a characteristic of the battery cell is simulated, comprising at least one output parameter from a simulated voltage (US), a simulated temperature (TS), a simulated state of charge (SOC) and a power limit, on the basis of a battery cell model (BM) according to input parameters comprising at least the previously measured current (I) and the previously measured temperature (TM). The simulated output parameter of the state of charge (SOC) is corrected on the basis of a predictive filter algorithm according to the measured voltage (UM) and the simulated voltage (US). Finally, to optimize the battery cell model (BM), a stored model parameter of the internal resistance (RG) is updated using a value which has been determined by the method for determining a varying internal resistance (RG) of a battery cell.

The application provides a thermal runaway early warning method and device for an energy storage battery, electronic equipment and a storage medium. The thermal runaway early warning method comprises the following steps: obtaining impedance spectrum data of a target energy storage battery at different temperatures and SOC; preprocessing the impedance spectrum data to obtain first data; determining a Nyquist diagram of the target energy storage battery according to the first data, fitting element parameter values of the target energy storage battery, and determining an equivalent impedance model; standardizing the element parameter values; analyzing the standardized element parameter values and operation data through a temperature relationship analysis model to predict the relationship between the standardized element parameter values and the internal temperature of the target energy storage battery, and then determining the predicted internal temperature; comparing the internal temperature with a preset thermal runaway condition, and early warning the thermal runaway of the target energy storage battery according to the comparison result. The application has the beneficial effect of improving the accuracy of battery thermal runaway early warning.

Provided are a battery diagnosis device and a battery diagnosis method using same, the device being capable of accurately measuring battery faults according to alternating current impedance data of a battery, measured using electrochemical impedance spectroscopy. The battery diagnosis device according to one aspect of the present invention comprises: a diagnosis model formation unit, which forms a first Nyquist plot in which determination points forming the shape of a Nyquist plot are marked using electrochemical impedance spectroscopy and using first alternating current impedance data as reference alternating current impedance data measured for a first battery, which a normal battery, at different frequencies; and a battery fault diagnosis unit which forms a second Nyquist plot in which determination points forming the shape of a Nyquist plot are marked using the electrochemical impedance spectroscopy and using second alternating current impedance data measured for a second battery, which is a battery to be diagnosed for faults, at different frequencies, and which compares the first Nyquist plot and the second Nyquist plot so as to diagnose faults in the second battery.

The invention discloses an electrode slurry moisture detection method, the electrode slurry comprises a binder, the binder comprises polyvinylidene fluoride (PVDF), the detection method comprises the following steps: obtaining a Nyquist diagram of the electrode slurry, the Nyquist diagram comprises a high-frequency region and a non-high-frequency region; determining a tangent line of the tail end of the Nyquist curve in the non-high-frequency region; if an included angle is formed between the extension direction of the tangent line and the positive direction of the horizontal axis of the Nyquist diagram, the included angle is an acute angle, and a real part impedance value corresponding to an intersection point of the tangent line and the horizontal axis does not exceed a preset value, determining that the moisture of the electrode slurry exceeds the standard; wherein the extension direction is the direction from the tangent point of the tangent line to the intersection point. The invention further discloses an electrode slurry moisture detection device, a computer storage medium and electronic equipment.

A battery diagnosis device according to an aspect of the present invention comprises: a diagnosis model construction unit configured to construct a first Nyquist plot, in which determination parameters constituting a form of a Nyquist plot are displayed by using first AC impedance data that is reference AC impedance data measured for a first battery, which is a normal battery at different frequencies, by means of electrochemical impedance spectroscopy (EIS), and derive measurement parameters matching the determination parameters from an equivalent circuit model that is constructed by using second AC impedance data measured for a second battery, which is a failure diagnosis target battery at different frequencies, by means of the electrochemical impedance spectroscopy; and a battery failure diagnosis unit configured to diagnose a failure of the second battery by comparing at least one of the determination parameters and at least one of the measurement parameters.

To provide an information processing system capable of estimating the full-charge capacity of a power storage device early and with high accuracy.SOLUTION: An information processing system includes a control device that executes a capacity estimation process for estimating a full-charge capacity of a power storage device. The capacity estimation process is the process that estimates the full-charge capacity of the power storage device on the basis of a fitting curve of a Nyquist plot on which results of AC impedance measurement of the power storage device are plotted. An OCV-SOC curve of the power storage device in an initial-state in which an internal pressure of the power storage device is lower than a reference pressure includes a flat region and a steep region. The control device executes the capacity estimation process in a state where an OCV of the power storage device is within a first flat region when the internal pressure of the power storage device is lower than the reference pressure, and executes the capacity estimation process in a state where the OCV of the power storage device is within a second flat region when the internal pressure of the power storage device is higher than the reference pressure. The second flat region is narrower than the first flat region.SELECTED DRAWING: Figure 2

The present application belongs to the technical field of printed circuit board manufacturing, and relates to a PCB blind hole electroplating hole filling method, comprising the following steps: assembling a response signal stream to generate composite response current data; aggregating a two-dimensional Nyquist graph to generate a time-frequency domain electrochemical resonance vector; merging multi-dimensional digital parameters to establish a physical characteristic parameter vector; encapsulating target pulse waveform parameters according to a preset communication protocol to generate a pulse configuration vector; generating an in-situ peeling interface in combination with an electrostrictive stress; and generating a solid blind hole according to a directional cathode deposition waveform electroplating. The present application solves the problem that the existing blind hole electroplating process is difficult to perform in-situ diagnosis and self-adaptive differential repair on the microscopic pollution state of a single blind hole, thereby leading to the problem that the hole filling yield is not stable enough.

To provide an electrochromic sheet capable of quick color development, a laminate, an eyeglass lens and eyeglasses.SOLUTION: An EC sheet includes a first substrate, a second substrate, an EC element, and an encapsulation part. The EC element includes a first transparent electrode, a second transparent electrode and an EC layer. An impedance per unit area of the EC sheet is measured at response frequency within a range of 0.1 Hz to 1 MHz in a condition with applied voltage 0 V and amplitude 10 mV, a requirement (2) is satisfied in a Nyquist diagram obtained from a measurement: (2) a tilt of an approximation straight line is 25 or less in a graphic chart in which an imaginary number component is within a range of 7.0 Ω / cm2 to 14.0 Ω / cm2.SELECTED DRAWING: Figure 5

The present invention is intended to provide a technique capable of accurately and rapidly diagnosing a battery's condition without pre-accumulating measurement data. A battery diagnostic device according to the present invention specifies a first frequency at which a component caused by a diffusion resistance of an equivalent circuit of a battery begins to appear in a Nyquist diagram of the battery; specifies a second frequency at which a phase of the voltage and a phase of the current coincide in phase-frequency characteristics of the voltage and current; and diagnoses a battery's condition using the respective real parts of a first impedance of the battery at the first frequency and a second impedance of the battery at the second frequency.

Provided is a photoelectric conversion element having improved durability while achieving high initial photoelectric conversion efficiency. The photoelectric conversion element includes a first electrode, a second electrode, and a photoelectric conversion layer including a crystal of a perovskite structure, and is characterized in that: when the smaller one of an electrode area of the first electrode and an electrode area of the second electrode is S [cm2], S [cm2] is S [cm2] in a Nyquist map based on an impedance measurement result; the maximum value Rrecc [omega] among resistance values obtained by fitting an arc corresponding to a phase maximum value in a low-frequency range by a parallel circuit of the resistive element and the constant-phase element satisfies the following formula (E1): 1.0 * 104 lt; rrec* Slt; 1.0 * 107 (E1), and a maximum value Rct [Omega] and Rrecc [Omega] among resistance values obtained by fitting an arc corresponding to a phase maximum value in a high-frequency range by a parallel circuit of the resistive element and the constant-phase element satisfy the following equation (E2): Rrecc / Rct > = 25 (E2).

To provide an electrochromic sheet capable of quick color development, a laminate, a spectacle lens, and a spectacle.SOLUTION: An electrochromic sheet comprises a first substrate, a second substrate, an EC element, and an encapsulating part. The EC element includes a first transparent electrode, a second transparent electrode, and an EC layer. When impedance of the EC sheet per unit area is measured under the condition of applied voltage of 0 V and amplitude of 10 mV within a range of response frequency from 0.1 Hz to 1 MHz, the following requirements (1) to (3) are satisfied in Nyquist diagram obtained from the measurement result. (1) A first intersection point of a horizontal axis of the Nyquist diagram and chart is 1.0 Ω / cm2 or more and 8.0 Ω / cm2 or less. (2) Approximation straight line of the chart of imaginary number component falls within a range of 7.0 Ω / cm2 or more and 14.0 Ω / cm2 or less is inclined at 25 or less. (3) A value ([value of second intersection point between approximation straight line and horizontal axis]-[value of first intersection point]) is 5.0 Ω / cm2 or less.SELECTED DRAWING: Figure 5

The present invention uses the absolute value |Z| of an impedance Z which has been extracted at a frequency equal to or lower than the frequency at the apex of a semicircle (Nyquist plot) in the GEIS method or the PEIS method to evaluate, from a change in the absolute value |Z| over time, the corrosion resistance of a constituent material of a working electrode to be evaluated.

The invention discloses a stability judgment method and device applied to a virtual inertia control system. The method comprises the following steps: constructing a state space model of the virtual inertia control system; converting the state space model into a multivariable system transfer function matrix G (s), wherein s is a Laplace operator; drawing a Nyquist diagram with a Gerer round belt of the system transfer function matrix G (s); and if the virtual inertia control system meets the use condition of the combined criterion based on the Gerer round belt, judging the stability of the virtual inertia control system by using the combined criterion. According to the method, the calculation complexity is remarkably reduced, a direct and visual reference is provided for optimal selection of key parameters such as a virtual inertia coefficient, and the applicability and efficiency in engineering practice are greatly improved.

An electrochromic sheet, which is an EC sheet, comprises a first substrate, a second substrate, an EC element, and a sealing part. The EC element has a first transparent electrode, a second transparent electrode, and an EC layer. When the impedance per unit area of the EC sheet is measured in a response frequency range of 0.1 Hz to 1 MHz under conditions of an applied voltage of 0 V and an amplitude of 10 mV, the following requirements (1) to (3) are satisfied in a Nyquist diagram obtained from the measurement result. (1) The first intersection point between the graph and the horizontal axis of the Nyquist diagram is at 1.0-8.0 Ω / cm2. <sp / > (2) The slope of the approximate straight line of the graph in the range of an imaginary component of 7.0-14.0 Ω / cm2 is 25 or less. <sp / > (3) The value of A ([the value of a second intersection point between the approximate straight line and the horizontal axis] - [the value of the first intersection point]) is 5.0 Ω / cm2 or less.

To provide an electrochromic sheet capable of quick color development, a laminate, an eyeglass lens and eyeglasses.SOLUTION: An EC sheet includes a first substrate, a second substrate, an EC element, and an encapsulation part. The EC element includes a first transparent electrode, a second transparent electrode and an EC layer. An impedance per unit area of the EC sheet is measured at response frequency within a range of 0.1 Hz to 1 MHz in a condition with applied voltage 0 V, and amplitude 10 mV, a requirement (3) is satisfied, in a Nyquist diagram obtained from a measurement: (3) A value A below is 5.0 Ω / cm2 or less, the value A=[a value at a second intersection in a Nyquist diagram]-[a value at a first intersection in the Nyquist diagram] (The first intersection represents an intersection within a range of 0 Ω / cm2 to 8.0 Ω / cm2 a lateral axis in the Nyquist diagram and a graphic chart of the Nyquist diagram, and the second intersection represents an intersection of an approximation straight line and a lateral axis when a graphic chart is linear-approximated).SELECTED DRAWING: Figure 5

This invention relates to a management device for detecting defects in the busbar fastening and cell-to-cell welding conditions of a battery pack using electrochemical impedance spectroscopy (EIS) technology. The device comprises: a current generation unit for applying a set alternating current to the battery pack; a voltage measurement unit for measuring the voltage generated at each battery cell or across the busbars by means of the current; an impedance calculation unit for calculating impedance using the measured current and voltage values; and a data output unit for generating a Nyquist plot or Bode plot based on the calculated impedance and outputting the impedance change.