Megawatt charging device trend detection method and device

Abstract

The application discloses a megawatt charging device state detection method and device, comprising: establishing a plurality of megawatt charging circuit models equivalent to the megawatt charging device; for each megawatt charging circuit model, extracting a plurality of power test points from a working power interval, and testing the output voltage of the megawatt charging circuit model and the megawatt charging device under different input voltages under different load impedances at each power test point; according to the test data, a theoretical function and a measured function are fitted; the corresponding megawatt charging circuit model is corrected based on the error of the theoretical function and the measured function, and is stored in a model library; the measured function of a megawatt charging device to be tested is obtained, the closest theoretical function to the measured function is searched in the model library, and the megawatt charging circuit model corresponding to the theoretical function is used for simulation detection. The application realizes the detection of the megawatt charging device.

Description

Technical Field

[0001] This invention relates to charging detection technology, and more particularly to a method and apparatus for detecting the status of a megawatt-level charging device. Background Technology

[0002] In recent years, the new energy vehicle industry has developed rapidly. As of the end of 2022, high-power charging devices, as the energy source for electric vehicles, have played an indispensable role in accelerating the development of the new energy vehicle industry. However, due to the lack of unified testing standards for charging devices, the current testing platforms can only detect power levels up to hundreds of kilowatts, and do not have the capability to test megawatt-level charging devices. Therefore, suitable testing methods are urgently needed to test and analyze megawatt-level charging devices of different levels and topologies. Summary of the Invention

[0003] Purpose of the invention: This invention addresses the problems existing in the prior art by providing a method and apparatus for detecting the status of megawatt-level charging devices.

[0004] Technical solution: The megawatt-level charging device status detection method of the present invention includes the following steps:

[0005] Establish several megawatt-level charging circuit models equivalent to megawatt-level charging devices;

[0006] For each megawatt-level charging circuit model, several power test points are extracted from the operating power range, and the output voltage of the megawatt-level charging circuit model and the megawatt-level charging device under different load impedances and different input voltages is tested at each power test point.

[0007] Based on the test data, a theoretical function characterizing the relationship between the output voltage, input voltage, and load impedance of the megawatt-level charging circuit model and a measured function characterizing the relationship between the output voltage, input voltage, and load impedance of the megawatt-level charging device were obtained by fitting.

[0008] Error correction is performed on the corresponding megawatt-level charging circuit model based on theoretical and measured functions, and the corrected megawatt-level charging circuit models and corresponding theoretical functions are stored in the model library.

[0009] Obtain the measured function of the megawatt-level charging device to be tested, and search the model library for the theoretical function that is closest to the measured function. Then, use the megawatt-level charging circuit model corresponding to the theoretical function for simulation testing.

[0010] Furthermore, the extraction of several power test points from the operating power range specifically includes:

[0011] The operating power range is divided into several power sub-ranges;

[0012] Based on the measured power distribution of the megawatt-level charging device, calculate the average power value and standard deviation power value for each power sub-interval;

[0013] For each power sub-interval, the maximum power value of the interval that satisfies the standard normal cumulative integral distribution is obtained based on the average power value and the standard deviation power value.

[0014] Each power sub-interval is corrected to the range between the maximum power value of the previous power sub-interval and the maximum power value of the current power sub-interval;

[0015] Several power test points are extracted at equal intervals from each power sub-interval after correction.

[0016] Furthermore, the calculation of the average power value and standard deviation power value for each power sub-interval based on the measured operating power distribution of the megawatt-level charging device specifically includes:

[0017] Obtain actual power distribution data of a megawatt-level charging device within a charging cycle;

[0018] The power distribution data is sampled at equal intervals, and the number of sampling points in each power sub-interval is counted.

[0019] The average power value and standard deviation power value of each power sub-interval are calculated according to the following formula based on the number of sampling points:

[0020]

[0021]

[0022] In the formula, μ i σ i Let n represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, where m represents the number of power subintervals, and n represents the number of power subintervals. i This represents the number of sampling points located in the i-th power sub-interval. This represents the k-th sampling point located in the i-th power sub-interval.

[0023] Furthermore, obtaining the maximum power value within an interval that satisfies a standard normal cumulative integral distribution based on the average power value and the standard deviation power value specifically includes:

[0024] The normal cumulative probability of the center value of the power subinterval is calculated based on the average power value and the standard deviation power value using the following formula:

[0025]

[0026] In the formula, M i x represents the center value of the i-th power sub-interval. i The normal cumulative probability, μ iσ i Let represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, and m represent the number of power subintervals;

[0027] The maximum power value of the interval is calculated according to the following formula based on the normal cumulative probability:

[0028]

[0029] In the formula, P iMax φ represents the maximum power value of the i-th power sub-interval. -1 () represents the inverse cumulative distribution function of the standard normal distribution.

[0030] Furthermore, the step of extracting several power test points at equal intervals from each corrected power sub-interval specifically includes:

[0031] For each power sub-interval, the weights are calculated as follows:

[0032]

[0033] In the formula, P0 represents the minimum value of the operating power range, and λ i Let represent the weight of the i-th power subinterval, m represent the number of power subintervals, and x represent the power variable;

[0034] For each power sub-interval, with d i Extract power test points for spacing:

[0035]

[0036] In the formula, P iMax P (i-1)Max Let represent the maximum power values ​​of the i-th and i-1th power sub-intervals, respectively.

[0037] Furthermore, the error correction model based on theoretical and measured functions corresponds to a megawatt-level charging circuit model, specifically including:

[0038] For each megawatt-level charging circuit model, the error between the theoretical function and the measured function within the preset adjustable input voltage range is calculated. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range.

[0039] For each megawatt-level charging circuit model, the error between the theoretical function and the measured function within the preset adjustable load impedance range is calculated. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range.

[0040] The megawatt-level charging device status detection device of the present invention includes:

[0041] The simulation model building module is used to build several megawatt-level charging circuit models equivalent to megawatt-level charging devices.

[0042] The power test point extraction module is used to extract several power test points from the operating power range for each megawatt-level charging circuit model.

[0043] The first test module is used to test the output voltage of the megawatt-level charging circuit model under different load impedances and different input voltages at each power test point;

[0044] The second test module is used to test the output voltage of the megawatt-level charging device under different load impedances and different input voltages at each power test point;

[0045] The fitting module is used to fit the theoretical function characterizing the relationship between the output voltage and input voltage and load impedance of the megawatt-level charging circuit model and the measured function characterizing the relationship between the output voltage and input voltage and load impedance of the megawatt-level charging device based on the test data.

[0046] The correction module is used to correct the error of the corresponding megawatt-level charging circuit model based on the theoretical function and the measured function.

[0047] A model library is used to store the corrected models of each megawatt-level charging circuit and their corresponding theoretical functions.

[0048] The retrieval module obtains the measured function of the megawatt-level charging device to be tested, and retrieves the theoretical function that is closest to the measured function in the model library;

[0049] The detection module is used to perform detection using the megawatt-level charging circuit model corresponding to the retrieved theoretical function.

[0050] Furthermore, the power test point extraction module specifically includes:

[0051] Sub-interval division unit, used to divide the working power range into several power sub-intervals;

[0052] The parameter solving unit is used to calculate the average power value and standard deviation power value of each power sub-interval according to the measured working power distribution of the megawatt-level charging device;

[0053] The interval maximum power solution unit is used to obtain the interval maximum power value that satisfies the standard normal cumulative integral distribution for each power sub-interval based on the average power value and the standard deviation power value.

[0054] The sub-interval correction unit is used to correct each power sub-interval to the range between the maximum power value of the previous power sub-interval and the maximum power value of the current power sub-interval.

[0055] The test point extraction unit is used to extract several power test points at equal intervals from each corrected power sub-interval.

[0056] Furthermore, the parameter solving unit specifically includes:

[0057] The power distribution acquisition subunit is used to acquire the actual power distribution data of the megawatt-level charging device during a charging cycle.

[0058] The sampling sub-unit is used to sample the power distribution data at equal intervals and count the number of sampling points in each power sub-interval.

[0059] The parameter calculation subunit is used to calculate the average power value and standard deviation power value for each power sub-interval according to the number of sampling points using the following formula:

[0060]

[0061]

[0062] In the formula, μ i σ i Let n represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, where m represents the number of power subintervals, and n represents the number of power subintervals. i This represents the number of sampling points located in the i-th power sub-interval. This represents the k-th sampling point located in the i-th power sub-interval.

[0063] Furthermore, the interval maximum power calculation unit specifically includes:

[0064] The cumulative probability calculation subunit is used to calculate the normal cumulative probability of the center value of the power subinterval based on the average power value and the standard deviation power value according to the following formula:

[0065]

[0066] In the formula, M i x represents the center value of the i-th power sub-interval. i The normal cumulative probability, μ i σ i Let represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, and m represent the number of power subintervals;

[0067] The interval maximum power calculation subunit is used to calculate the interval maximum power value based on the normal cumulative probability according to the following formula:

[0068]

[0069] In the formula, P iMax φ represents the maximum power value of the i-th power sub-interval. -1() represents the inverse cumulative distribution function of the standard normal distribution.

[0070] Furthermore, the test point extraction unit specifically includes:

[0071] The weight calculation subunit is used to calculate the weights for each power sub-interval as follows:

[0072]

[0073] In the formula, P0 represents the minimum value of the operating power range, and λ i Let represent the weight of the i-th power subinterval, m represent the number of power subintervals, and x represent the power variable;

[0074] Test point extraction sub-units are used for each power sub-interval, in d i Extract power test points for spacing:

[0075]

[0076] In the formula, P iMax P (i-1)Max Let represent the maximum power values ​​of the i-th and i-1th power sub-intervals, respectively.

[0077] Furthermore, the correction module specifically includes:

[0078] The first calibration unit is used to calculate the error between the theoretical function and the measured function within the preset adjustable input voltage range for each megawatt-level charging circuit model. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range.

[0079] The second correction unit is used to calculate the error between the theoretical function and the measured function within a preset adjustable load impedance range for each megawatt-level charging circuit model. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range.

[0080] The present invention also discloses a computer-readable medium storing a computer program, which executes the above-described megawatt-level charging device status detection method when running.

[0081] Compared with the prior art, the beneficial effects of this invention are as follows: This invention establishes a model library of megawatt-level charging circuit models. During testing, by fitting the measured function, the most matching megawatt-level charging circuit model is found in the model library for simulation testing. There is no need to build an actual charging device, which solves the problem that megawatt-level charging devices cannot be tested in practice. Attached Figure Description

[0082] Figure 1 This is a flowchart illustrating the megawatt-level charging device status detection method provided by the present invention.

[0083] Figure 2 This is a module structure diagram of the megawatt-level charging device status detection device provided by the present invention. Detailed Implementation

[0084] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0085] Example 1

[0086] This embodiment provides a method for status detection of megawatt-level charging devices, such as... Figure 1 As shown, it includes the following steps:

[0087] S101. Establish several megawatt-level charging circuit models equivalent to megawatt-level charging devices.

[0088] The megawatt-level charging circuit model mainly consists of a DC output, a megawatt-level converter, and cascaded loads. Commonly used circuit models can be selected, such as LLC full-bridge resonant topologies and phase-shifted full-bridge topologies. The more comprehensive the megawatt-level charging circuit models, the higher the accuracy of subsequent testing. By analyzing the working principle and operating modes of the megawatt-level charging circuit models, the different component parameters within the topology can be determined to achieve a specified megawatt-level power.

[0089] S102. For each megawatt-level charging circuit model, extract several power test points from the operating power range, and test the output voltage of the megawatt-level charging circuit model and the megawatt-level charging device under different load impedances and different input voltages at each power test point.

[0090] The specific methods for extracting power test points include:

[0091] S1021. Divide the operating power range into several power sub-ranges.

[0092] Taking a megawatt-level charging circuit model as an example, the operating power range [P0, P...] is... m The region is divided into m equal power sub-intervals, namely [P0, P1], [P1, P2], ..., [P...]. i-1 ,P i ],…,[P m-1 ,P mLet X be the subinterval X1, X2, ..., Xn. i ,…,X m .

[0093] S1022. Based on the measured operating power distribution of the megawatt-level charging device, calculate the average power value and standard deviation power value of each power sub-interval.

[0094] In practice, the actual power distribution data of the megawatt-level charging device corresponding to the circuit model within one charging cycle can be obtained; the power distribution data can be sampled at equal intervals, for example, 1000 sampling points can be sampled at a time interval of T / 1000, and the number of sampling points in each power sub-interval can be counted; based on the number of sampling points, the average power value and standard deviation power value of each power sub-interval can be calculated according to the following formula:

[0095]

[0096]

[0097] In the formula, μ i σ i Let X represent the i-th power sub-interval respectively. i The average power value and the standard deviation power value, where m represents the number of power subintervals, and n i This represents the number of sampling points located in the i-th power sub-interval. This represents the k-th sampling point located in the i-th power sub-interval.

[0098] S1023. For each power sub-interval, obtain the maximum power value of the interval that satisfies the standard normal cumulative integral distribution based on the average power value and the standard deviation power value.

[0099] In practice, the normal cumulative probability of the center value of the power sub-interval is first calculated based on the average power value and the standard deviation power value using the following formula:

[0100]

[0101] In the formula, M i x represents the center value of the i-th power sub-interval. i The normal cumulative probability, μ i σ i Let represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, and m represent the number of power subintervals;

[0102] Secondly, the maximum power value of the interval is calculated according to the following formula based on the normal cumulative probability:

[0103]

[0104] In the formula, P iMaxφ represents the maximum power value of the i-th power sub-interval. -1 () represents the inverse cumulative distribution function of the standard normal distribution.

[0105] S1024. Each power sub-interval is corrected to be the range between the maximum power value of the previous power sub-interval and the maximum power value of the current power sub-interval. This addresses the differences in the actual power range of the intervals caused by performance differences of different devices, environmental factors, etc.

[0106] S1025. Extract several power test points at equal intervals from each corrected power sub-interval.

[0107] In practice, the weights for each power sub-interval are calculated as follows:

[0108]

[0109] In the formula, P0 represents the minimum value of the operating power range, and λ i Let represent the weight of the i-th power subinterval, m represent the number of power subintervals, and x represent the power variable;

[0110] Then for each power sub-interval, with d i Extract power test points for spacing:

[0111]

[0112] In the formula, P iMax P (i-1)Max Let represent the maximum power values ​​of the i-th and i-1th power sub-intervals, respectively.

[0113] S103. Based on the test data, fit the theoretical function characterizing the relationship between the output voltage, input voltage, and load impedance of the megawatt-level charging circuit model, and the measured function characterizing the relationship between the output voltage, input voltage, and load impedance of the megawatt-level charging device.

[0114] When fitting, the input voltage and load impedance are used as independent variables, and the output voltage is used as the dependent variable. Fitting methods such as exponential function fitting and Gaussian fitting can be used.

[0115] S104. Based on the error correction of theoretical functions and measured functions, the corresponding megawatt-level charging circuit model is established, and the corrected megawatt-level charging circuit models and corresponding theoretical functions are stored in the model library.

[0116] During calibration, for each megawatt-level charging circuit model, the error between the theoretical function and the measured function within a preset adjustable input voltage range is calculated. If the error exceeds the preset range, for example, if the total error is 1%, the internal component parameters of the megawatt-level charging circuit model are calibrated until the error is within the preset range. Then, for each megawatt-level charging circuit model, the error between the theoretical function and the measured function within a preset adjustable load impedance range is calculated. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are calibrated until the error is within the preset range.

[0117] S105. Obtain the measured function of the megawatt-level charging device to be tested, and search the model library for the theoretical function that is closest to the measured function. Use the megawatt-level charging circuit model corresponding to the theoretical function for simulation testing.

[0118] The method for obtaining the measured function of the megawatt-level charging device under test can refer to step S103, that is, first test its input voltage v, load impedance r and output voltage and other parameters, and then fit the measured function. Once the megawatt-level charging circuit model corresponding to this theoretical function is retrieved, various simulation tests can be performed using this megawatt-level charging circuit model, solving the problem that actual megawatt-level charging devices cannot be tested.

[0119] Example 2

[0120] This embodiment provides a megawatt-level charging device status detection device, such as... Figure 2 As shown, it includes:

[0121] The simulation model building module 201 is used to build several megawatt-level charging circuit models equivalent to megawatt-level charging devices.

[0122] The power test point extraction module 202 is used to extract several power test points from the working power range for each megawatt-level charging circuit model.

[0123] The first test module 203 is used to test the output voltage of the megawatt-level charging circuit model under different load impedances and different input voltages at each power test point;

[0124] The second test module 204 is used to test the output voltage of the megawatt-level charging device under different load impedances and different input voltages at each power test point;

[0125] The fitting module 205 is used to fit the theoretical function characterizing the relationship between the output voltage and input voltage and load impedance of the megawatt-level charging circuit model and the measured function characterizing the relationship between the output voltage and input voltage and load impedance of the megawatt-level charging device based on the test data.

[0126] The correction module 206 is used to correct the error of the corresponding megawatt-level charging circuit model based on the theoretical function and the measured function.

[0127] Model library 207 is used to store the corrected megawatt-level charging circuit models and corresponding theoretical functions;

[0128] The retrieval module 208 obtains the measured function of the megawatt-level charging device to be tested, and retrieves the theoretical function that is closest to the measured function in the model library;

[0129] The detection module 209 is used to perform detection using the megawatt-level charging circuit model corresponding to the retrieved theoretical function.

[0130] The power test point extraction module specifically includes:

[0131] Sub-interval division unit, used to divide the working power range into several power sub-intervals;

[0132] The parameter solving unit is used to calculate the average power value and standard deviation power value of each power sub-interval according to the measured working power distribution of the megawatt-level charging device;

[0133] The interval maximum power solution unit is used to obtain the interval maximum power value that satisfies the standard normal cumulative integral distribution for each power sub-interval based on the average power value and the standard deviation power value.

[0134] The sub-interval correction unit is used to correct each power sub-interval to the range between the maximum power value of the previous power sub-interval and the maximum power value of the current power sub-interval.

[0135] The test point extraction unit is used to extract several power test points at equal intervals from each corrected power sub-interval.

[0136] Specifically, the parameter solving unit includes:

[0137] The power distribution acquisition subunit is used to acquire the actual power distribution data of the megawatt-level charging device during a charging cycle.

[0138] The sampling sub-unit is used to sample the power distribution data at equal intervals and count the number of sampling points in each power sub-interval.

[0139] The parameter calculation subunit is used to calculate the average power value and standard deviation power value for each power sub-interval according to the number of sampling points using the following formula:

[0140]

[0141]

[0142] In the formula, μ i σ iLet n represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, where m represents the number of power subintervals, and n represents the number of power subintervals. i This represents the number of sampling points located in the i-th power sub-interval. This represents the k-th sampling point located in the i-th power sub-interval.

[0143] Specifically, the interval maximum power calculation unit includes:

[0144] The cumulative probability calculation subunit is used to calculate the normal cumulative probability of the center value of the power subinterval based on the average power value and the standard deviation power value according to the following formula:

[0145]

[0146] In the formula, M i x represents the center value of the i-th power sub-interval. i The normal cumulative probability, μ i σ i Let represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, and m represent the number of power subintervals;

[0147] The interval maximum power calculation subunit is used to calculate the interval maximum power value based on the normal cumulative probability according to the following formula:

[0148]

[0149] In the formula, P iMax φ represents the maximum power value of the i-th power sub-interval. -1 () represents the inverse cumulative distribution function of the standard normal distribution.

[0150] The test point extraction unit specifically includes:

[0151] The weight calculation subunit is used to calculate the weights for each power sub-interval as follows:

[0152]

[0153] In the formula, P0 represents the minimum value of the operating power range, and λ i Let represent the weight of the i-th power subinterval, m represent the number of power subintervals, and x represent the power variable;

[0154] Test point extraction sub-units are used for each power sub-interval, in d i Extract power test points for spacing:

[0155]

[0156] In the formula, P iMax P (i-1)MaxLet represent the maximum power values ​​of the i-th and i-1th power sub-intervals, respectively.

[0157] Specifically, the correction module includes:

[0158] The first calibration unit is used to calculate the error between the theoretical function and the measured function within the preset adjustable input voltage range for each megawatt-level charging circuit model. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range.

[0159] The second correction unit is used to calculate the error between the theoretical function and the measured function within a preset adjustable load impedance range for each megawatt-level charging circuit model. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range.

[0160] The apparatus of this embodiment can be implemented in software and / or hardware, and can be used to execute the method provided in Embodiment 1 of the present invention, possessing the corresponding functions and beneficial effects of executing the method.

[0161] It is worth noting that in the embodiments of the above-mentioned determining device, the various units and modules included are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of each functional unit are only for easy differentiation and are not used to limit the scope of protection of the present invention.

[0162] The embodiments described above are merely illustrative, and the modules described as separate components may or may not be physically separate. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art will clearly understand that each implementation can be achieved using software plus necessary general-purpose hardware platforms, or it can be implemented solely through hardware, as long as the function or purpose can be achieved.

[0163] Example 3

[0164] This invention provides a storage medium containing a computer-executable program, which, when executed by a computer processor, is used to perform the method of Embodiment 1.

[0165] The storage medium of embodiments of the present invention may be any combination of one or more computer-readable media. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0166] The code for a computer-executable program that performs the operations of this invention can be written in one or more programming languages ​​or a combination thereof. Programming languages ​​include object-oriented programming languages ​​such as Java, Smalltalk, and C++, as well as conventional procedural programming languages ​​such as C or similar languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0167] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

Claims

1. A megawatt charging device situation detection method, characterized in that, Includes the following steps: Establish several megawatt-level charging circuit models equivalent to megawatt-level charging devices; For each megawatt-level charging circuit model, several power test points are extracted from the operating power range, and the output voltage of the megawatt-level charging circuit model and the megawatt-level charging device under different load impedances and different input voltages is tested at each power test point. Based on the test data, a theoretical function characterizing the relationship between the output voltage, input voltage, and load impedance of the megawatt-level charging circuit model and a measured function characterizing the relationship between the output voltage, input voltage, and load impedance of the megawatt-level charging device were obtained by fitting. Error correction is performed on the corresponding megawatt-level charging circuit model based on theoretical and measured functions, and the corrected megawatt-level charging circuit models and corresponding theoretical functions are stored in the model library. Obtain the measured function of the megawatt-level charging device to be tested, and search the model library for the theoretical function that is closest to the measured function. Then, use the megawatt-level charging circuit model corresponding to the theoretical function for simulation testing. The extraction of several power test points from the operating power range specifically includes: The operating power range is divided into several power sub-ranges; Based on the measured power distribution of the megawatt-level charging device, calculate the average power value and standard deviation power value for each power sub-interval; For each power sub-interval, the maximum power value of the interval that satisfies the standard normal cumulative integral distribution is obtained based on the average power value and the standard deviation power value. Each power sub-interval is corrected to the range between the maximum power value of the previous power sub-interval and the maximum power value of the current power sub-interval; Extract several power test points at equal intervals from each power sub-interval after correction; The extraction of several power test points at equal intervals from each corrected power sub-interval specifically includes: For each power sub-interval, the weights are calculated as follows: , In the formula, P0 represents the minimum value of the operating power range. Let represent the weight of the i-th power subinterval, m represent the number of power subintervals, and x represent the power variable; For each power sub-interval, with Extract power test points for spacing: , In the formula, Let represent the maximum power values ​​of the i-th and i-1th power sub-intervals, respectively.

2. The megawatt-level charging device status detection method according to claim 1, characterized in that, The calculation of the average power value and standard deviation power value for each power sub-interval based on the measured operating power distribution of the megawatt-level charging device specifically includes: Obtain actual power distribution data of a megawatt-level charging device within a charging cycle; The power distribution data is sampled at equal intervals, and the number of sampling points in each power sub-interval is counted. The average power value and standard deviation power value of each power sub-interval are calculated according to the following formula based on the number of sampling points: , , In the formula, , Let m represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, and m represent the number of power subintervals. This represents the number of sampling points located in the i-th power sub-interval. This represents the k-th sampling point located in the i-th power sub-interval.

3. The megawatt-level charging device status detection method according to claim 1, characterized in that, The step of obtaining the maximum power value of the interval satisfying the standard normal cumulative integral distribution based on the average power value and the standard deviation power value specifically includes: The normal cumulative probability of the center value of the power subinterval is calculated based on the average power value and the standard deviation power value using the following formula: , In the formula, x represents the center value of the i-th power sub-interval. i The normal cumulative probability, , Let represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, and m represent the number of power subintervals; The maximum power value of the interval is calculated according to the following formula based on the normal cumulative probability: , In the formula, This represents the maximum power value of the i-th power sub-interval. This represents the inverse cumulative distribution function of the standard normal distribution.

4. The megawatt-level charging device status detection method according to claim 1, characterized in that, The error correction model based on theoretical and measured functions corresponds to a megawatt-level charging circuit, specifically including: For each megawatt-level charging circuit model, the error between the theoretical function and the measured function within the preset adjustable input voltage range is calculated. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range. For each megawatt-level charging circuit model, the error between the theoretical function and the measured function within the preset adjustable load impedance range is calculated. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range.

5. A megawatt-level charging device status detection device, characterized in that, include: The simulation model building module is used to build several megawatt-level charging circuit models equivalent to megawatt-level charging devices. The power test point extraction module is used to extract several power test points from the operating power range for each megawatt-level charging circuit model. The first test module is used to test the output voltage of the megawatt-level charging circuit model under different load impedances and different input voltages at each power test point; The second test module is used to test the output voltage of the megawatt-level charging device under different load impedances and different input voltages at each power test point; The fitting module is used to fit the theoretical function characterizing the relationship between the output voltage and input voltage and load impedance of the megawatt-level charging circuit model and the measured function characterizing the relationship between the output voltage and input voltage and load impedance of the megawatt-level charging device based on the test data. The correction module is used to correct the error of the corresponding megawatt-level charging circuit model based on the theoretical function and the measured function. A model library is used to store the corrected models of each megawatt-level charging circuit and their corresponding theoretical functions. The retrieval module obtains the measured function of the megawatt-level charging device to be tested, and retrieves the theoretical function that is closest to the measured function in the model library; The detection module is used to perform detection using the megawatt-level charging circuit model corresponding to the retrieved theoretical function; The power test point extraction module specifically includes: Sub-interval division unit, used to divide the working power range into several power sub-intervals; The parameter solving unit is used to calculate the average power value and standard deviation power value of each power sub-interval according to the measured working power distribution of the megawatt-level charging device; The interval maximum power solution unit is used to obtain the interval maximum power value that satisfies the standard normal cumulative integral distribution for each power sub-interval based on the average power value and the standard deviation power value. The sub-interval correction unit is used to correct each power sub-interval to the range between the maximum power value of the previous power sub-interval and the maximum power value of the current power sub-interval. The test point extraction unit is used to extract several power test points at equal intervals from each corrected power sub-interval. The test point extraction unit specifically includes: The weight calculation subunit is used to calculate the weights for each power sub-interval as follows: , In the formula, P0 represents the minimum value of the operating power range. Let represent the weight of the i-th power subinterval, m represent the number of power subintervals, and x represent the power variable; Test point extraction sub-units are used for each power sub-interval to... Extract power test points for spacing: , In the formula, Let represent the maximum power values ​​of the i-th and i-1th power sub-intervals, respectively.

6. The megawatt-level charging device status detection device according to claim 5, characterized in that, The parameter solving unit specifically includes: The power distribution acquisition subunit is used to acquire the actual power distribution data of the megawatt-level charging device during a charging cycle. The sampling sub-unit is used to sample the power distribution data at equal intervals and count the number of sampling points in each power sub-interval. The parameter calculation subunit is used to calculate the average power value and standard deviation power value for each power sub-interval according to the number of sampling points using the following formula: , , In the formula, , Let m represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, and m represent the number of power subintervals. This represents the number of sampling points located in the i-th power sub-interval. This represents the k-th sampling point located in the i-th power sub-interval.

7. The megawatt-level charging device status detection device according to claim 5, characterized in that, The interval maximum power calculation unit specifically includes: The cumulative probability calculation subunit is used to calculate the normal cumulative probability of the center value of the power subinterval based on the average power value and the standard deviation power value according to the following formula: , In the formula, x represents the center value of the i-th power sub-interval. i The normal cumulative probability, , Let represent the average power value and the standard deviation power value of the i-th power subinterval, respectively, and m represent the number of power subintervals; The interval maximum power calculation subunit is used to calculate the interval maximum power value based on the normal cumulative probability according to the following formula: , In the formula, This represents the maximum power value of the i-th power sub-interval. This represents the inverse cumulative distribution function of the standard normal distribution.

8. The megawatt-level charging device status detection device according to claim 5, characterized in that, The correction module specifically includes: The first calibration unit is used to calculate the error between the theoretical function and the measured function within the preset adjustable input voltage range for each megawatt-level charging circuit model. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range. The second correction unit is used to calculate the error between the theoretical function and the measured function within a preset adjustable load impedance range for each megawatt-level charging circuit model. If the error exceeds the preset range, the internal component parameters of the megawatt-level charging circuit model are corrected until the error is within the preset range.

9. A computer-readable medium storing a computer program that, when executed, performs the megawatt-level charging device status detection method as described in any one of claims 1-4.

Images