A method, system, device and medium for detecting battery pack fault of a switching power supply cabinet

Abstract

The present invention relates to the field of battery pack detection technology, and in particular to a battery pack fault detection method, system, device and medium for a switch power supply cabinet. The method considers the influence of the environment on the battery pack, performs impedance equivalence on the battery pack of the switch power supply cabinet and the external air bag of the battery pack as a whole, obtains an equivalent impedance model of the battery pack, and uses the equivalent impedance model to construct an admittance matrix of the battery pack. By considering that the battery pack has different charged working states, harmonic flow calculations are performed on multiple different harmonic disturbances according to the admittance matrix of the battery pack to obtain the impedance change rate of each single cell in the battery pack, and form an impedance change observation matrix of the battery pack. The impedance change observation matrix is ​​used to predict the impedance change of each single cell, thereby performing fault detection on the working state of the single cell, improving the accuracy of battery pack fault detection, and realizing subsequent accurate prediction of the battery state.

Description

Technical Field

[0001] The present invention relates to the technical field of battery pack detection, and in particular to a battery pack fault detection method, system, device and medium for a switch power supply cabinet. Background Art

[0002] Switching power supply cabinet is an electrical device used in power system, which integrates multiple functions. It is mainly used to convert high voltage electric energy into low voltage electric energy suitable for industrial, commercial or household use, and provides various protection and control functions in the process.

[0003] Among them, the battery is a key component in the switching power supply cabinet. Its status is directly related to whether it can provide reliable backup power when the main power fails. It needs to be tested to ensure the reliability of the system, especially in those scenarios that require uninterruptible power supply (UPS) support.

[0004] There are usually multiple batteries in a switch power cabinet. At the same time, multiple batteries are connected in parallel, which will cause mutual influence between the battery packs and will also be affected by the external environment. At present, the battery pack fault detection of the switch power cabinet only detects the independent battery pack, which will result in inaccurate battery pack fault detection of the switch power cabinet and difficulty in subsequent accurate prediction of the battery status. Summary of the invention

[0005] In view of this, the present invention provides a battery pack fault detection method, system, device and medium for a switching power supply cabinet, which solves the technical problems that the current battery pack fault detection of the switching power supply cabinet is not accurate enough and it is difficult to make subsequent accurate predictions of the battery status.

[0006] A first aspect of the present invention provides a method for detecting a battery failure of a switching power supply cabinet, comprising:

[0007] Perform impedance equivalence on a battery pack of a switch power supply cabinet and an air bag outside the battery pack to obtain an equivalent impedance model of the battery pack;

[0008] Constructing an admittance matrix of the battery pack according to the equivalent impedance model;

[0009] Performing harmonic power flow calculations on a plurality of different harmonic disturbances according to the admittance matrix of the battery pack, obtaining impedance change rates of each single battery in the battery pack, and forming an impedance change observation matrix of the battery pack;

[0010] The impedance change of each of the single cells is predicted according to the impedance change observation matrix of the battery pack, and the prediction result is used to perform fault detection on the working state of the single cell.

[0011] Preferably, the battery pack comprises a plurality of the single cells, and the plurality of the single cells are connected in parallel in a plurality of rows and columns;

[0012] The impedance equivalence of the battery pack of the switch power supply cabinet and the external air bag of the battery pack is performed to obtain an equivalent impedance model of the battery pack, including:

[0013] For each of the single cells, the single cell is equivalent to an impedance loop, wherein the impedance loop includes a capacitor, an inductor and a resistor, and the capacitor, the inductor and the resistor are sequentially connected in series to form the impedance loop;

[0014] Connecting the plurality of impedance loops in parallel according to the topological connection relationship of the plurality of single cells to form a total impedance loop;

[0015] The external air bag of the battery pack is equivalent to a grounded temperature control resistor, and the grounded temperature control resistor is bypass-connected to each of the outermost impedance loops of the total impedance loop to form an equivalent impedance model of the battery pack.

[0016] Preferably, constructing the admittance matrix of the battery pack according to the equivalent impedance model includes:

[0017] According to Kirchhoff's voltage law, construct the voltage small signal vector and the current small signal vector of each impedance loop;

[0018] The admittance matrix of the impedance loop is constructed according to the voltage small signal vector and the current small signal vector of the impedance loop; the admittance matrix is:

[0019]

[0020] In the formula, is the current small signal vector of the i-th impedance loop, is the node admittance matrix of the ith impedance loop, is the voltage small signal vector of the i-th impedance loop; where the node admittance matrix for:

[0021]

[0022] In the formula, , All are self-admittance, , All are mutual admittance, wherein, when the impedance loop is not directly connected to the grounded temperature-controlled resistor, the mutual admittance is zero; when the impedance loop is directly connected to the grounded temperature-controlled resistor, the mutual admittance is calculated as:

[0023]

[0024] In the formula, To find the derivative symbol, is the current flowing through the impedance loop, is the voltage across the temperature-controlled resistor at temperature t;

[0025] A total admittance matrix of a plurality of the impedance loops is constructed according to the admittance matrix of the impedance loop as the admittance matrix of the battery pack.

[0026] Preferably, the harmonic power flow calculation is performed on a plurality of different harmonic disturbances according to the admittance matrix of the battery pack to obtain the impedance change rate of each single battery in the battery pack and form an impedance change observation matrix of the battery pack, including:

[0027] Introducing a plurality of harmonic sources of different frequencies into the admittance matrix of the battery pack to obtain a harmonic system equation;

[0028] Performing matrix inversion calculation on the harmonic system equation to obtain the harmonic voltage of each single cell under a plurality of harmonic sources with different frequencies;

[0029] Determining harmonic current according to the harmonic voltage of each of the single cells under a plurality of harmonic sources with different frequencies;

[0030] Determining the impedance of each of the single cells under a plurality of harmonic sources of different frequencies according to the harmonic voltage and the harmonic current;

[0031] Determining the impedance change rate of each of the single cells according to the impedance of each of the single cells under a plurality of harmonic sources of different frequencies;

[0032] The impedance change observation matrix of the battery pack is determined according to the impedance change rate of each of the single cells.

[0033] Preferably, predicting the impedance change of each of the single cells according to the impedance change observation matrix of the battery pack, and performing fault detection on the working state of the single cell using the prediction result, comprises:

[0034] Determine the impedance change rate sequence data of each of the single cells according to the impedance change observation matrix of the battery pack;

[0035] Based on the pre-trained impedance time series prediction model, the impedance change rate of the single battery at a future moment is predicted according to the impedance change rate sequence data to obtain the impedance change rate prediction value of each single battery;

[0036] Determining impedance change trend data of each of the single cells according to the impedance change rate prediction value of each of the single cells;

[0037] For each of the single cells, determining a deviation rate between the impedance change trend data of the single cell and preset impedance change rate reference data;

[0038] It is determined that the single battery has a fault according to the deviation rate.

[0039] Preferably, the determining of the deviation rate between the impedance change trend data of the single cell and preset impedance change rate reference data includes:

[0040] Determining the deviation rate at each time and frequency according to the impedance change trend data of the single battery and the preset impedance change rate reference data;

[0041] The determining, according to the deviation rate, whether the single battery has a fault includes:

[0042] Determine whether the deviation rate falls within a preset confidence interval, wherein the preset confidence interval is ,in, is the lower limit of the confidence interval, is the upper limit of the confidence interval, , is the sample mean, is the score given by the confidence level, is the standard error, , where s is the sample standard deviation and n is the sample size;

[0043] When it is determined that the deviation rate falls within the preset confidence interval, the deviation rate is determined to be normal, and it is determined that there is no fault in the single cell;

[0044] When it is determined that the deviation rate does not fall within the preset confidence interval, the deviation rate is determined to be abnormal, and it is determined that the single cell has a fault.

[0045] Preferably, the method further comprises:

[0046] Determining an impedance variation curve of the battery pack according to an equivalent impedance model of the battery pack;

[0047] Performing a fast Fourier transform on the impedance change curve to obtain an impedance change frequency domain curve;

[0048] Determine the peak offset according to the impedance change frequency domain curve;

[0049] Determining whether the peak offset is greater than a preset peak offset threshold;

[0050] When it is determined that the peak offset is greater than the preset peak offset threshold, it is determined that a fault exists in the battery pack.

[0051] In a second aspect, the present invention further provides a battery pack fault detection system for a switching power supply cabinet, comprising:

[0052] An impedance equivalent module is used to perform impedance equivalence on a battery pack of a switch power supply cabinet and an external air bag of the battery pack to obtain an equivalent impedance model of the battery pack;

[0053] An admittance module, used for constructing an admittance matrix of the battery pack according to the equivalent impedance model;

[0054] An impedance observation determination module, used to perform harmonic power flow calculation on a plurality of different harmonic disturbances according to the admittance matrix of the battery pack, obtain the impedance change rate of each single battery in the battery pack, and form an impedance change observation matrix of the battery pack;

[0055] The fault detection module is used to predict the impedance change of each of the single cells according to the impedance change observation matrix of the battery pack, and perform fault detection on the working state of the single cell using the prediction result.

[0056] In a third aspect, the present invention further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the battery pack fault detection method for the switching power supply cabinet as described in the first aspect.

[0057] In a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, the steps of the method for detecting a battery pack fault in a switching power supply cabinet as described in the first aspect are implemented.

[0058] It can be seen from the above technical solutions that the present invention considers the influence of the environment on the battery pack, and performs impedance equivalence on the battery pack of the switch power supply cabinet and the external air bag of the battery pack as a whole to obtain an equivalent impedance model of the battery pack, and uses the equivalent impedance model to construct the admittance matrix of the battery pack. By considering that the battery pack has different charged working states, harmonic flow calculations are performed on multiple different harmonic disturbances according to the admittance matrix of the battery pack to obtain the impedance change rate of each single cell in the battery pack, and an impedance change observation matrix of the battery pack is formed. The impedance change observation matrix is ​​used to predict the impedance change of each single cell, thereby performing fault detection on the working state of the single cell, improving the accuracy of battery pack fault detection, and realizing subsequent accurate prediction of the battery state. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0060] Figure 1 An application environment of a battery pack fault detection method for a switching power supply cabinet provided by an embodiment of the present invention;

[0061] Figure 2 A flow chart of a method for detecting a battery pack failure in a switching power supply cabinet provided by an embodiment of the present invention;

[0062] Figure 3 A schematic diagram of an impedance circuit of a single cell provided in an embodiment of the present invention;

[0063] Figure 4 A schematic diagram of an equivalent impedance model of a battery pack provided in an embodiment of the present invention;

[0064] Figure 5 A schematic diagram of the structure of a battery pack fault detection system for a switching power supply cabinet provided by an embodiment of the present invention;

[0065] Figure 6 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0066] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0067] The battery pack fault detection method of the switching power supply cabinet provided in the embodiment of the present application can be applied to Figure 1In the application environment shown. Among them, the battery pack 101 of the switch power cabinet communicates with the terminal 102, and the battery pack of the switch power cabinet includes multiple single cells, and the multiple single cells are connected in parallel. The terminal 102 performs impedance equivalence on the battery pack of the switch power cabinet and the external air bag of the battery pack to obtain an equivalent impedance model of the battery pack; constructs the admittance matrix of the battery pack according to the equivalent impedance model; performs harmonic flow calculations on multiple different harmonic disturbances according to the admittance matrix of the battery pack to obtain the impedance change rate of each single cell in the battery pack, and forms an impedance change observation matrix of the battery pack; predicts the impedance change of each single cell according to the impedance change observation matrix of the battery pack, and uses the prediction results to perform fault detection on the working state of the single cell. Among them, the terminal 102 can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server that provides cloud computing services.

[0068] like Figure 2 As shown, the embodiment of the present application provides a battery pack fault detection method for a switch power supply cabinet, and the method is applied to Figure 1 The terminal 102 in the example is used as an example to illustrate, including the following steps S1 to S4. Among them:

[0069] Step S1, performing impedance equivalence on a battery pack of a switch power supply cabinet and an air bag outside the battery pack to obtain an equivalent impedance model of the battery pack.

[0070] It can be understood that the battery pack includes a plurality of single cells, and the plurality of single cells are connected in parallel in a plurality of rows and columns.

[0071] For the battery pack in the switching power cabinet, since other components in the cabinet are working, heat will be generated to disturb the battery pack. Therefore, the embodiment of the present application takes into account the impact of the heat in the air layer on the battery. The embodiment of the present application treats the battery pack of the switching power cabinet and the external air bag of the battery pack as a whole for impedance equivalence, wherein the thickness of the external air bag of the battery pack can be designed according to the critical change of heat, such as 5mm thickness.

[0072] In this embodiment, step S1 performs impedance equivalence on the battery pack of the switch power supply cabinet and the air bag outside the battery pack to obtain an equivalent impedance model of the battery pack, including:

[0073] Step S101: for each single battery, the single battery is equivalent to an impedance loop, the impedance loop includes a capacitor, an inductor and a resistor, and the capacitor, the inductor and the resistor are connected in series in sequence to form an impedance loop.

[0074] Among them, the impedance circuit of the single cell is as follows: Figure 3 As shown, the capacitor C1, the inductor L and the resistor R1 are connected in series in sequence to form an impedance loop.

[0075] Step S102: multiple impedance loops are connected in parallel according to the topological connection relationship of multiple single cells to form a total impedance loop.

[0076] The multiple single cells of the battery pack form an array structure, and multiple impedance loops are connected in parallel according to the topological connection relationship of the multiple single cells to form a total impedance loop. Since the lines between the single cells are short, the impedance is extremely small and can be ignored.

[0077] Step S103: The external air bag of the battery pack is equivalent to a grounded temperature control resistor, and the grounded temperature control resistor is bypass-connected to each of the outermost impedance loops of the total impedance loop to form an equivalent impedance model of the battery pack.

[0078] It is understandable that the external air of the battery pack generally has a greater impact on the outermost single cell of the battery pack, while the impact on other single cells is very small and can be ignored. At the same time, since the external air bag is affected by temperature, it can be equivalent to a grounded temperature control resistor, and the grounded temperature control resistor is bypassed with each impedance loop at the outermost edge of the total impedance loop, thereby reflecting that the change of the temperature control resistor affects the current distribution of the single cell. The equivalent impedance model of the battery pack is as follows: Figure 4 As shown, the temperature control resistor is Rz.

[0079] Step S2: constructing an admittance matrix of the battery pack according to the equivalent impedance model.

[0080] Specifically, the step S2 of constructing the admittance matrix of the battery pack according to the equivalent impedance model includes:

[0081] Step S201: construct voltage small signal vectors and current small signal vectors of each impedance loop according to Kirchhoff's voltage law.

[0082] Among them, based on Kirchhoff's voltage law, the algebraic sum of the voltage drops on all elements of the impedance loop is equal to the sum of the electromotive force in the loop. Considering that the impedance loop is composed of a resistor, a capacitor, and an inductor in series, the voltage small signal vector and the current small signal vector of each impedance loop can be expressed as:

[0083]

[0084] In the formula, , , They represent the inductor voltage, resistor voltage and capacitor voltage respectively. , , Represent the inductor current, resistor current and capacitor current respectively;

[0085] in,

[0086] In the formula, is the inductance at complex frequency s, d is the derivative symbol, For time, is the resistance at complex frequency s, is the capacitance at complex frequency s.

[0087] Step S202: construct an admittance matrix of the impedance loop according to the voltage small signal vector and the current small signal vector of the impedance loop; the admittance matrix is:

[0088]

[0089] In the formula, is the current small signal vector of the i-th impedance loop, is the node admittance matrix of the ith impedance loop, is the voltage small signal vector of the i-th impedance loop; where the node admittance matrix for:

[0090]

[0091] In the formula, , All are self-admittance, , All are mutual admittance. When the impedance loop is not directly connected to the grounded temperature-controlled resistor, the mutual admittance is zero; when the impedance loop is directly connected to the grounded temperature-controlled resistor, the mutual admittance is calculated as:

[0092]

[0093] In the formula, To find the derivative symbol, is the current flowing through the impedance loop, is the voltage across the temperature-controlled resistor at temperature t.

[0094] It is understandable that the admittance matrix will depend on the specific connection method of the battery pack (series, parallel or mixed). For the parallel relationship, the admittance matrix contains off-diagonal elements to represent the interaction between different single cells. Therefore, for the impedance loop, the influence of itself should be considered, and the influence of other impedance loops and external air bags on the impedance loop should also be considered. In particular, since the resistance value of the temperature-controlled resistor will change with temperature, this will affect the mutual admittance of the entire system. Therefore, when the impedance loop is directly connected to the grounded temperature-controlled resistor, it is necessary to consider the influence of the external air bag on the impedance loop to calculate the mutual admittance. Among them, the main function of the temperature-controlled resistor is to sense temperature changes, and its resistance value changes with temperature. For the temperature-controlled resistor, the relationship between resistance Rz and temperature t can be expressed by a simplified exponential model:

[0095]

[0096] In the formula, is the reference temperature The resistance value under is a constant, is the air density.

[0097] Among them, the relationship between the temperature control resistor Rz and the voltage across the temperature control resistor is:

[0098]

[0099] In the formula, is the reference current of the temperature control resistor.

[0100] Step S203: constructing a total admittance matrix of multiple impedance loops according to the admittance matrix of the impedance loop as the admittance matrix of the battery pack.

[0101] The total admittance matrix of the multiple impedance loops is obtained by adding the admittance matrices of the multiple impedance loops.

[0102] Step S3: perform harmonic power flow calculation on a plurality of different harmonic disturbances according to the admittance matrix of the battery pack, obtain the impedance change rate of each single battery in the battery pack, and form an impedance change observation matrix of the battery pack.

[0103] It is understandable that when the battery pack is in different working conditions, the battery pack has multiple charge state changes, making it volatile, such as floating charge state, charging state and power supply state, etc. The embodiment of the present application regards the charge state changes of the battery pack in different working conditions as harmonic disturbances at multiple different frequencies.

[0104] Specifically, in step S3, harmonic power flow calculation is performed on multiple different harmonic disturbances according to the admittance matrix of the battery pack to obtain the impedance change rate of each single battery in the battery pack, and form an impedance change observation matrix of the battery pack, including:

[0105] Step S301: introducing a plurality of harmonic sources of different frequencies into the admittance matrix of the battery pack to obtain a harmonic system equation.

[0106] Among them, it is assumed that there are m harmonic sources I with different frequencies h (k), where k=1,2,...,m, k=1,2,...,m. The harmonic source can be a current source or a voltage source, depending on the specific working state. Introducing these harmonic sources into the admittance matrix, the harmonic system equation is formed as follows:

[0107]

[0108] In the formula, is the admittance matrix, is the harmonic voltage vector of each single battery in the battery pack, is the harmonic source current vector.

[0109] Step S302: Perform matrix inversion calculation on the harmonic system equation to obtain the harmonic voltage of each single cell under multiple harmonic sources of different frequencies.

[0110] Among them, by inverting the harmonic system equation through the matrix, the harmonic voltage of each single cell under multiple harmonic sources of different frequencies is obtained:

[0111]

[0112] Step S303: determining the harmonic current according to the harmonic voltage of each single battery under multiple harmonic sources of different frequencies.

[0113] Among them, according to the calculated harmonic voltage V h , combined with the admittance matrix Y(s), the harmonic current flowing through each single cell can be further analyzed. The harmonic current of each single cell can be expressed as:

[0114]

[0115] In the formula, is the harmonic current of single cell i, , They represent self-admittance and mutual-admittance respectively, and j is the serial number of the single cell.

[0116] Step S304: determining the impedance of each single cell under multiple harmonic sources of different frequencies according to the harmonic voltage and the harmonic current.

[0117] Among them, the impedance of each single cell under multiple harmonic sources of different frequencies is obtained by calculating the ratio of harmonic voltage and harmonic current, which is expressed as:

[0118]

[0119] In the formula, is the impedance of the single cell under the harmonic source of frequency f.

[0120] Step S305 : determining the impedance change rate of each single cell according to the impedance of each single cell under multiple harmonic sources of different frequencies.

[0121] The impedance change rate can be defined as the percentage change of the impedance at the harmonic frequency relative to the initial impedance under the fundamental frequency or DC conditions, that is, the impedance change rate of the single cell is:

[0122]

[0123] In the formula, is the impedance change rate of the single cell, is the initial impedance value under reference conditions (usually fundamental frequency or DC conditions).

[0124] Step S306: Determine the impedance change observation matrix of the battery pack according to the impedance change rate of each single battery.

[0125] The impedance change rate of the single battery can be normalized, and the impedance change observation matrix of the battery pack can be determined using the normalized impedance change rate. k , a vector ΔZ(f k ), where ΔZ(f k )=[ΔZ 1 (f 1 ),Z 2 (f 2 ),Z(f 3 )...Z n (f k )] T , where n is the number of single cells.

[0126] In order to form the impedance change observation matrix of the entire battery pack, the impedance change vectors at all different harmonic frequencies can be arranged in columns, and the impedance change observation matrix H is in the following form:

[0127]

[0128] Each row of the impedance change observation matrix H represents the impedance change rate of a single cell at all harmonic frequencies, and each column represents the impedance change rate of all battery cells at a specific harmonic frequency. By comparing the observation matrices at different time points, the change trend of each single cell over time can be identified. This helps to discover abnormal changes or potential problems.

[0129] Step S4: predict the impedance change of each single cell according to the impedance change observation matrix of the battery pack, and use the prediction result to perform fault detection on the working state of the single cell.

[0130] In some embodiments, the step S4 predicts the impedance change of each single cell according to the impedance change observation matrix of the battery pack, and uses the prediction result to perform fault detection on the working state of the single cell, including:

[0131] Step S401: Determine the impedance change rate sequence data of each single battery according to the impedance change observation matrix of the battery pack.

[0132] Step S402: Based on the pre-trained impedance time series prediction model, the impedance change rate of the single battery at a future moment is predicted according to the impedance change rate sequence data to obtain the impedance change rate prediction value of each single battery.

[0133] Among them, the training process of the pre-trained impedance time series prediction model is:

[0134] By obtaining the historical data of the impedance change rate sequence of the single battery and forming a training data set, the training data set is trained using a bidirectional long short-term memory network to obtain an impedance time series prediction model.

[0135] Step S403: determining the impedance change trend data of each single cell according to the impedance change rate prediction value of each single cell.

[0136] The impedance change trend data of each single cell can be determined through the predicted values ​​of the impedance change rate of each single cell at multiple moments in the future.

[0137] Step S404: for each single cell, determine the deviation rate between the impedance change trend data of the single cell and the preset impedance change rate reference data.

[0138] The deviation rate at each time and frequency can be determined through a ratio relationship between the impedance change trend data of the single battery and the preset impedance change rate reference data.

[0139] Step S405: determine whether a single cell battery is faulty based on the deviation rate.

[0140] In some embodiments, determining whether a single cell battery is faulty according to the deviation rate in step S405 includes:

[0141] Step S4051: Determine whether the deviation rate falls within a preset confidence interval, where the preset confidence interval is ,in, is the lower limit of the confidence interval, is the upper limit of the confidence interval, , is the sample mean, is the score given by the confidence level, is the standard error, , where s is the sample standard deviation and n is the sample size;

[0142] Step S4052: When it is determined that the deviation rate falls within the preset confidence interval, the deviation rate is determined to be normal, and it is determined that there is no fault in the single cell;

[0143] Step S4053: When it is determined that the deviation rate does not fall within the preset confidence interval, the deviation rate is determined to be abnormal, and it is determined that the single cell has a fault.

[0144] It is understood that an appropriate confidence level (such as 95%) is selected to construct the confidence interval. This confidence level determines the degree of confidence in the estimated results. By using the standard error and the selected confidence level, a confidence interval is constructed at each time point. Among them, for a 95% confidence level, a z-score of 1.96 is usually used (assuming that the data follows a normal distribution).

[0145] If the deviation rate falls within the confidence interval, the deviation is considered normal; otherwise, it is considered to be a significant deviation. The larger the absolute value of the deviation rate, the more serious the deviation. Through the confidence interval-based method, I can effectively determine the deviation rate of the impedance change trend data from the preset impedance change rate benchmark data and evaluate its significance.

[0146] In some embodiments, in order to facilitate direct detection of a fault of the entire battery pack, the embodiment of the present application further provides a process for detecting a fault of the entire battery pack, including:

[0147] Step S501: determining an impedance variation curve of the battery pack according to an equivalent impedance model of the battery pack.

[0148] Among them, the voltage and current values ​​output by the battery pack can be determined through the equivalent impedance model of the battery pack, the voltage and current values ​​output by the battery pack can be used to determine the impedance of the battery pack, the impedance change of the battery pack can be used to determine the impedance amplitude and impedance phase, and the impedance change curve can be drawn using the impedance amplitude and impedance phase.

[0149] Step S502: Perform fast Fourier transform on the impedance change curve to obtain an impedance change frequency domain curve.

[0150] Among them, by performing fast Fourier transform on the impedance change curve, the time domain relationship can be converted into the frequency domain to obtain the impedance change frequency domain curve.

[0151] Step S503: determine the peak offset according to the impedance variation frequency domain curve.

[0152] Step S504: determine whether the peak offset is greater than a preset peak offset threshold.

[0153] In order to determine the peak offset based on the impedance change frequency domain curve, it is necessary to systematically analyze the key features in the frequency domain curve and compare them with a reference curve or benchmark data. The reference curve can be based on specifications provided by historical data.

[0154] The peak value of the impedance change frequency domain curve is detected using a peak detection method (such as the local extreme value method, the threshold value method, etc.), and the corresponding frequency and impedance value are extracted using the peak value of the impedance change frequency domain curve. The peak offset is determined by the difference between the actual measured peak position and the corresponding peak position in the reference curve.

[0155] The peak shift threshold is set through manual experience, and the peak shift value is compared with the peak shift value to determine whether the peak shift value is normal. If it is abnormal, it means that the single cell may be caused by parameter changes.

[0156] Step S505: When it is determined that the peak offset is greater than the preset peak offset threshold, it is determined that the battery pack has a fault.

[0157] It should be noted that the embodiment of the present application considers the influence of the environment on the battery pack, and performs impedance equivalence on the battery pack of the switch power cabinet and the external air bag of the battery pack as a whole to obtain an equivalent impedance model of the battery pack, and uses the equivalent impedance model to construct the admittance matrix of the battery pack. By considering that the battery pack has different charged working states, harmonic flow calculations are performed on multiple different harmonic disturbances according to the admittance matrix of the battery pack to obtain the impedance change rate of each single cell in the battery pack, and form an impedance change observation matrix of the battery pack. The impedance change observation matrix is ​​used to predict the impedance change of each single cell, thereby performing fault detection on the working state of the single cell, improving the accuracy of battery pack fault detection, and realizing subsequent accurate prediction of the battery state.

[0158] Based on the same inventive concept, an embodiment of the present application further provides a battery pack fault detection system for a switching power supply cabinet for implementing the above-mentioned battery pack fault detection method for a switching power supply cabinet.

[0159] The implementation solution to the problem provided by the system is similar to the implementation solution recorded in the above method. Therefore, the specific limitations in the battery pack fault detection system embodiments of one or more switch power cabinets provided below can be referred to the limitations on the battery pack fault detection method of the switch power cabinet above, and will not be repeated here.

[0160] like Figure 5 As shown, the embodiment of the present application also provides a battery pack fault detection system for a switching power supply cabinet, including:

[0161] The impedance equivalent module 100 is used to perform impedance equivalence on the battery pack of the switch power supply cabinet and the air bag outside the battery pack to obtain an equivalent impedance model of the battery pack;

[0162] An admittance module 200, used to construct an admittance matrix of the battery pack according to an equivalent impedance model;

[0163] The impedance observation determination module 300 is used to perform harmonic power flow calculation on multiple different harmonic disturbances according to the admittance matrix of the battery pack, obtain the impedance change rate of each single battery in the battery pack, and form an impedance change observation matrix of the battery pack;

[0164] The fault detection module 400 is used to predict the impedance change of each single cell according to the impedance change observation matrix of the battery pack, and perform fault detection on the working state of the single cell using the prediction result.

[0165] In some embodiments, the battery pack includes a plurality of single cells, and the plurality of single cells are connected in parallel in a plurality of rows and columns;

[0166] The impedance of the battery pack of the switch power supply cabinet and the air bag outside the battery pack is equivalent to obtain the equivalent impedance model of the battery pack, including:

[0167] For each single battery, the single battery is equivalent to an impedance loop, which includes a capacitor, an inductor and a resistor, and the capacitor, the inductor and the resistor are connected in series in sequence to form an impedance loop;

[0168] Connecting multiple impedance loops in parallel according to the topological connection relationship of multiple single cells to form a total impedance loop;

[0169] The external air bag of the battery pack is equivalent to a grounded temperature control resistor, and the grounded temperature control resistor is bypass-connected to each of the outermost impedance loops of the total impedance loop to form an equivalent impedance model of the battery pack.

[0170] In some embodiments, constructing an admittance matrix of a battery pack according to an equivalent impedance model includes:

[0171] According to Kirchhoff's voltage law, the voltage small signal vector and current small signal vector of each impedance loop are constructed;

[0172] The admittance matrix of the impedance loop is constructed according to the voltage small signal vector and current small signal vector of the impedance loop; the admittance matrix is:

[0173]

[0174] In the formula, is the current small signal vector of the i-th impedance loop, is the node admittance matrix of the ith impedance loop, is the voltage small signal vector of the i-th impedance loop; where the node admittance matrix for:

[0175]

[0176] In the formula, , All are self-admittance, , All are mutual admittance. When the impedance loop is not directly connected to the grounded temperature-controlled resistor, the mutual admittance is zero; when the impedance loop is directly connected to the grounded temperature-controlled resistor, the mutual admittance is calculated as:

[0177]

[0178] In the formula, To find the derivative symbol, is the current flowing through the impedance loop, is the voltage across the temperature-controlled resistor at temperature t;

[0179] The total admittance matrix of the multiple impedance loops is constructed according to the admittance matrix of the impedance loop as the admittance matrix of the battery pack.

[0180] In some embodiments, harmonic power flow calculation is performed on multiple different harmonic disturbances according to the admittance matrix of the battery pack to obtain the impedance change rate of each single battery in the battery pack, and form an impedance change observation matrix of the battery pack, including:

[0181] Introducing multiple harmonic sources of different frequencies into the admittance matrix of the battery pack, the harmonic system equation is obtained;

[0182] Perform matrix inversion calculation on the harmonic system equation to obtain the harmonic voltage of each single cell under multiple harmonic sources of different frequencies;

[0183] Determine the harmonic current according to the harmonic voltage of each single battery under multiple harmonic sources of different frequencies;

[0184] Determine the impedance of each single cell under multiple harmonic sources of different frequencies according to the harmonic voltage and harmonic current;

[0185] Determine the impedance change rate of each single cell according to the impedance of each single cell under multiple harmonic sources of different frequencies;

[0186] The impedance change observation matrix of the battery pack is determined according to the impedance change rate of each single battery.

[0187] In some embodiments, the impedance change of each single cell is predicted according to the impedance change observation matrix of the battery pack, and the fault detection of the working state of the single cell is performed using the prediction result, including:

[0188] Determine the impedance change rate sequence data of each single battery according to the impedance change observation matrix of the battery pack;

[0189] Based on the pre-trained impedance time series prediction model, the impedance change rate of the single battery at the future moment is predicted according to the impedance change rate sequence data to obtain the impedance change rate prediction value of each single battery;

[0190] Determine the impedance change trend data of each single cell according to the impedance change rate prediction value of each single cell;

[0191] For each single cell, determining the deviation rate between the impedance change trend data of the single cell and the preset impedance change rate reference data;

[0192] It is judged that there is a fault in the single battery based on the deviation rate.

[0193] In some embodiments, determining the deviation rate between the impedance change trend data of the single cell and the preset impedance change rate reference data includes:

[0194] Determine the deviation rate at each time and frequency based on the impedance change trend data of the single battery and the preset impedance change rate benchmark data;

[0195] The single cell battery failure is judged based on the deviation rate, including:

[0196] Determine whether the deviation rate falls within the preset confidence interval, where the preset confidence interval is ,in, is the lower limit of the confidence interval, is the upper limit of the confidence interval, , is the sample mean, is the score given by the confidence level, is the standard error, , where s is the sample standard deviation and n is the sample size;

[0197] When the deviation rate is judged to fall within the preset confidence interval, the deviation rate is judged to be normal, and it is judged that there is no fault in the single battery;

[0198] When it is determined that the deviation rate does not fall within the preset confidence interval, the deviation rate is determined to be abnormal, and it is determined that the single cell has a fault.

[0199] In some embodiments, the system also includes: a battery pack fault detection module, which is used to determine the impedance change curve of the battery pack based on the equivalent impedance model of the battery pack; perform a fast Fourier transform on the impedance change curve to obtain an impedance change frequency domain curve; determine the peak offset based on the impedance change frequency domain curve; determine whether the peak offset is greater than a preset peak offset threshold; when it is determined that the peak offset is greater than the preset peak offset threshold, it is determined that the battery pack is faulty.

[0200] like Figure 6As shown, an embodiment of the present application also provides an electronic device, the electronic device 10 includes a memory 20 and a processor 30, the memory 20 stores a computer program, and when the computer program is executed by the processor 30, the processor 30 executes the steps of the battery pack fault detection method of the switching power cabinet in the above embodiment.

[0201] An embodiment of the present application further provides a computer-readable storage medium having a computer program stored thereon, and when the computer program is executed, the steps of the battery pack fault detection method for the switching power supply cabinet in the above embodiment are implemented.

[0202] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, electronic device and computer storage medium can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0203] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0204] In several embodiments provided by the present invention, it is understood that each box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and a part of a module, a program segment or a code includes one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved.

[0205] In the several embodiments provided by the present invention, it should be understood that the disclosed systems, electronic devices, computer storage media and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0206] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0207] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0208] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for executing all or part of the steps of the method described in each embodiment of the present invention through a computer device (which can be a personal computer, server, or network device, etc.). The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store program codes.

[0209] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting battery failure of a switching power supply cabinet, characterized in that: include: Perform impedance equivalence on a battery pack of a switch power supply cabinet and an air bag outside the battery pack to obtain an equivalent impedance model of the battery pack; Constructing an admittance matrix of the battery pack according to the equivalent impedance model; Performing harmonic power flow calculations on a plurality of different harmonic disturbances according to the admittance matrix of the battery pack, obtaining impedance change rates of each single battery in the battery pack, and forming an impedance change observation matrix of the battery pack; The impedance change of each of the single cells is predicted according to the impedance change observation matrix of the battery pack, and the prediction result is used to perform fault detection on the working state of the single cell.

2. The method for detecting battery failure of a switching power supply cabinet according to claim 1, characterized in that: The battery pack comprises a plurality of said single cells, and the plurality of said single cells are connected in parallel in a plurality of rows and columns; The impedance equivalence of the battery pack of the switch power supply cabinet and the external air bag of the battery pack is performed to obtain an equivalent impedance model of the battery pack, including: For each of the single cells, the single cell is equivalent to an impedance loop, wherein the impedance loop includes a capacitor, an inductor and a resistor, and the capacitor, the inductor and the resistor are connected in series in sequence to form the impedance loop; Connecting the plurality of impedance loops in parallel according to the topological connection relationship of the plurality of single cells to form a total impedance loop; The external air bag of the battery pack is equivalent to a grounded temperature control resistor, and the grounded temperature control resistor is bypass-connected to each of the outermost impedance loops of the total impedance loop to form an equivalent impedance model of the battery pack.

3. The method for detecting battery failure of a switching power supply cabinet according to claim 2, characterized in that: The step of constructing the admittance matrix of the battery pack according to the equivalent impedance model includes: According to Kirchhoff's voltage law, construct the voltage small signal vector and the current small signal vector of each impedance loop; The admittance matrix of the impedance loop is constructed according to the voltage small signal vector and the current small signal vector of the impedance loop; the admittance matrix is: ； In the formula, is the current small signal vector of the i-th impedance loop, is the node admittance matrix of the ith impedance loop, is the voltage small signal vector of the i-th impedance loop; where the node admittance matrix for: ； In the formula, , All are self-admittance, , All are mutual admittance, wherein, when the impedance loop is not directly connected to the grounded temperature-controlled resistor, the mutual admittance is zero; when the impedance loop is directly connected to the grounded temperature-controlled resistor, the mutual admittance is calculated as: ； In the formula, To find the derivative symbol, is the current flowing through the impedance loop, is the voltage across the temperature-controlled resistor at temperature t; A total admittance matrix of a plurality of the impedance loops is constructed according to the admittance matrix of the impedance loop as the admittance matrix of the battery pack.

4. The method for detecting battery failure of a switching power supply cabinet according to claim 1, characterized in that: The harmonic power flow calculation is performed on a plurality of different harmonic disturbances according to the admittance matrix of the battery pack to obtain the impedance change rate of each single battery in the battery pack and form an impedance change observation matrix of the battery pack, including: Introducing a plurality of harmonic sources of different frequencies into the admittance matrix of the battery pack to obtain a harmonic system equation; Performing matrix inversion calculation on the harmonic system equation to obtain the harmonic voltage of each single cell under a plurality of harmonic sources with different frequencies; Determining harmonic current according to the harmonic voltage of each of the single cells under a plurality of harmonic sources with different frequencies; Determining the impedance of each of the single cells under a plurality of harmonic sources of different frequencies according to the harmonic voltage and the harmonic current; Determining the impedance change rate of each of the single cells according to the impedance of each of the single cells under a plurality of harmonic sources of different frequencies; The impedance change observation matrix of the battery pack is determined according to the impedance change rate of each of the single cells.

5. The method for detecting battery failure of a switching power supply cabinet according to claim 1, characterized in that: The step of predicting the impedance change of each of the single cells according to the impedance change observation matrix of the battery pack, and performing fault detection on the working state of the single cell using the prediction result, comprises: Determine the impedance change rate sequence data of each of the single cells according to the impedance change observation matrix of the battery pack; Based on the pre-trained impedance time series prediction model, the impedance change rate of the single battery at a future moment is predicted according to the impedance change rate sequence data to obtain the impedance change rate prediction value of each single battery; Determining impedance change trend data of each of the single cells according to the impedance change rate prediction value of each of the single cells; For each of the single cells, determining a deviation rate between the impedance change trend data of the single cell and preset impedance change rate reference data; It is determined that the single battery has a fault according to the deviation rate.

6. The method for detecting battery failure of a switching power supply cabinet according to claim 5, characterized in that: The step of determining the deviation rate between the impedance change trend data of the single cell and preset impedance change rate reference data includes: Determining the deviation rate at each time and frequency according to the impedance change trend data of the single battery and the preset impedance change rate reference data; The determining, according to the deviation rate, whether the single battery has a fault includes: Determine whether the deviation rate falls within a preset confidence interval, wherein the preset confidence interval is ,in, is the lower limit of the confidence interval, is the upper limit of the confidence interval, , is the sample mean, is the score given by the confidence level, is the standard error, , where s is the sample standard deviation and n is the sample size; When it is determined that the deviation rate falls within the preset confidence interval, the deviation rate is determined to be normal, and it is determined that there is no fault in the single cell; When it is determined that the deviation rate does not fall within the preset confidence interval, the deviation rate is determined to be abnormal, and it is determined that the single cell has a fault.

7. The method for detecting battery failure of a switching power supply cabinet according to claim 1, characterized in that: Also includes: Determining an impedance variation curve of the battery pack according to an equivalent impedance model of the battery pack; Performing a fast Fourier transform on the impedance change curve to obtain an impedance change frequency domain curve; Determine the peak offset according to the impedance change frequency domain curve; Determining whether the peak offset is greater than a preset peak offset threshold; When it is determined that the peak offset is greater than the preset peak offset threshold, it is determined that a fault exists in the battery pack.

8. A battery pack fault detection system for a switching power supply cabinet, characterized in that: include: An impedance equivalent module is used to perform impedance equivalence on a battery pack of a switch power supply cabinet and an external air bag of the battery pack to obtain an equivalent impedance model of the battery pack; An admittance module, used for constructing an admittance matrix of the battery pack according to the equivalent impedance model; An impedance observation determination module, used to perform harmonic power flow calculation on a plurality of different harmonic disturbances according to the admittance matrix of the battery pack, obtain the impedance change rate of each single battery in the battery pack, and form an impedance change observation matrix of the battery pack; The fault detection module is used to predict the impedance change of each of the single cells according to the impedance change observation matrix of the battery pack, and perform fault detection on the working state of the single cell using the prediction result.

9. An electronic device, characterized in that: The electronic device includes a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the battery pack fault detection method for the switching power supply cabinet as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the steps of the method for detecting battery pack failure of a switching power supply cabinet according to any one of claims 1 to 7 are implemented.

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