Vehicle-mounted Distributed Energy Grid-connection Testing Method and Device Based on Modular Assembly

Abstract

This application relates to the technical field of energy grid connection testing, and specifically relates to a vehicle-mounted distributed energy grid connection testing method and device based on modular assembly, which specifically includes: obtaining each positive and negative voltage group in the voltage data based on the positive and negative conditions of the voltage at adjacent moments; determining the zero moment between the voltages in the positive and negative voltage groups based on the difference between the voltage values in the positive and negative voltage groups and combining the relative positions of the voltages in the positive and negative voltage groups in the coordinate system; calculating the working frequency at the current moment based on the time interval between two adjacent zero moments. Through the real-time frequency detection algorithm, the output frequency of the vehicle-mounted distributed energy can be quickly and accurately detected, avoiding the delay problem caused by the need to collect two cycle bands in the traditional Fourier transform, improving the timeliness of the grid connection test, and providing reliable data support for the grid connection operation.

Description

Technical Field

[0001] This application relates to the technical field of energy grid connection testing, and particularly to a vehicle-mounted distributed energy grid connection testing method and device based on modular assembly. Background Art

[0002] With the rapid development of new energy on the user side such as industrial and commercial energy storage, integrated charging and energy storage, distributed photovoltaics, and small wind turbines entering villages. Energy storage batteries can be used as carriers of vehicle-mounted distributed energy. The vehicle-mounted distributed energy is modularized. When the grid load is too heavy or the grid fails in a certain power grid, the vehicle-mounted distributed energy module is connected to the grid to perform grid connection for temporary handling of the grid fault. During the grid connection process, since the vehicle-mounted distributed energy requires a grid connection voltage, and the voltage magnitudes are different in different regions, such as 220V, 380V, 10kV, therefore, the vehicle-mounted distributed power supply needs to be tested before grid connection operation to ensure that the vehicle-mounted distributed power supply will not impact the main power grid and affect the stable operation of the main power grid after grid connection.

[0003] For the grid connection test of vehicle-mounted distributed energy, when the frequency of the vehicle-mounted distributed energy exceeds the specified range, the frequency deviation seriously affects the normal operation of relay protection equipment and safety automatic devices, and may even cause their misoperation, further expanding the accident range. Traditional technologies generally use Fourier transform to measure the frequency in the power grid. However, due to the high real-time nature of the use of vehicle-mounted distributed energy, and Fourier transform requires at least two periods of wavebands to be collected for frequency detection, which results in a delay in the detection process and cannot meet the real-time requirement. Therefore, there are certain limitations in using Fourier transform for grid connection testing of vehicle-mounted distributed power supplies. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a vehicle-mounted distributed energy grid connection testing method and device based on modular assembly, and the specific technical solutions adopted are as follows:

[0005] In a first aspect, an embodiment of this application provides a vehicle-mounted distributed energy grid connection testing method based on modular assembly, and this method includes the following steps:

[0006] Real-time collect voltage data of the vehicle-mounted distributed energy at each moment;

[0007] Obtain each positive and negative voltage group in the voltage data based on the positive and negative situations of the voltage at adjacent moments; when the voltage at the current moment and the previous moment form a positive and negative voltage group, the steps to obtain the grid connection state of the vehicle-mounted distributed energy and state adjustment are:

[0008] Calculate the proportional correction coefficient of the positive and negative voltage group based on the difference between the voltage values in the positive and negative voltage group and the time interval between adjacent moments;

[0009] Based on the relative positions of the voltages in the positive and negative voltage groups in the rectangular coordinate system, and combining with the relevant theorems of similar triangles, calculate the time interval between the voltage data in the positive and negative voltage groups and the corresponding zero point moments, denoted as the first time interval;

[0010] Determine the zero point moments between the voltages in the positive and negative voltage groups based on the proportional correction coefficient and the first time interval;

[0011] Calculate the working frequency at the current moment based on the time interval between two adjacent zero point moments;

[0012] Based on the working frequency, analyze the grid connection status of the on-vehicle distributed energy and perform status adjustment.

[0013] In one of the embodiments, the process of obtaining the voltage data of each positive and negative voltage group is as follows:

[0014] If the voltage at each moment is not zero, then analyze whether the positive and negative signs of the voltage at each moment and the voltage at its previous moment are the same. If they are different, then use the voltage at each moment and the voltage at its previous moment as a positive and negative voltage group.

[0015] In one of the embodiments, the process of obtaining the proportional correction coefficient of the positive and negative voltage groups is as follows:

[0016] Denote the proportional correction coefficient of the positive and negative voltage group formed by the voltage at the current moment and the voltage at its previous moment as , The expression of is: , respectively represent the normalized values of the voltage data at the previous moment and the current moment of the current moment; is the arcsine function; T represents the acquisition time interval between two adjacent voltage data; represents the exponential function with the natural constant as the base.

[0017] In one of the embodiments, the process of obtaining the time interval between the voltage data in the positive and negative voltage groups and the corresponding zero point is as follows:

[0018] Denote the voltage at the current moment and the voltage at its previous moment as and , denote the current moment and its previous moment as and , denote the zero point between and moments as the first zero point; wherein, the voltage value of the first zero point is 0;

[0019] Based on and , and , as well as the first zero point, to construct triangle and triangle ;

[0020] When triangle and triangle are similar, based on the relevant theorems of similar triangles, obtain the time interval between the previous moment of the current moment and the moment corresponding to the first zero point.

[0021] In one embodiment, the obtaining process of the triangle and the triangle is as follows:

[0022] Take the coordinate point as the coordinate point , take the coordinate point as the coordinate point , take the first zero point as the coordinate point , to obtain triangle ; take the coordinate point as the coordinate point , take the coordinate point as the coordinate point , to obtain triangle .

[0023] In one embodiment, the process of obtaining the time interval between the previous moment of the current moment and the moment corresponding to the first zero point is as follows:

[0024] When triangle is similar to triangle , there are: , and , where represents the time interval between the previous moment of the current moment and the moment corresponding to the first zero point; represents the time interval between the current moment and the moment corresponding to the first zero point; T represents the acquisition time interval between two adjacent voltage data;

[0025] Then 's expression is: .

[0026] In one embodiment, the expression of the zero point moment between the voltages in the positive and negative voltage groups is:

[0027] , in the formula, represents the current zero point moment; represents the previous moment of the current moment; It represents the proportional correction coefficient of the positive and negative voltage groups formed by the voltage at the current moment and the voltage at the previous moment; It represents the first time interval between the previous moment of the current moment and the first zero point; wherein, the current zero point moment is the real zero point moment between the current moment and the previous moment.

[0028] In one embodiment, the expression of the operating frequency at the current moment is:

[0029] , where, It represents the operating frequency at the current moment; 、 respectively represent the current zero point moment and the previous zero point moment; It represents a preset cycle coefficient.

[0030] In one embodiment, analyzing the grid connection state of the on-vehicle distributed energy and performing state adjustment specifically includes:

[0031] If the operating frequency at the current moment is less than the preset first frequency threshold or greater than the preset second frequency threshold, the on-vehicle distributed energy is in an abnormal operating state, and the on-vehicle distributed energy is immediately terminated from feeding power to the grid line;

[0032] If the operating frequency at the current moment is greater than or equal to the preset first frequency threshold and less than or equal to the preset second frequency threshold, the historical operating frequency is used as the input of the CPS1 index formula, and the output is the CPS1 value when the on-vehicle distributed energy is working. For the CPS1 value, if it is greater than or equal to 100%, the current grid connection state is maintained; if it is less than 100%, the AGC control strategy is optimized to adjust the current grid connection state.

[0033] In a second aspect, the embodiments of the present application further provide an on-vehicle distributed energy grid connection test device based on modular assembly, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the method described in any one of the above are implemented.

[0034] The embodiments of the present application at least have the following beneficial effects:

[0035] This application collects the voltage data of in-vehicle distributed energy at each moment in real time; obtains each positive and negative voltage group in the voltage data based on the positive and negative conditions of the voltage at adjacent moments; calculates the proportional correction coefficient of the positive and negative voltage groups based on the difference between the voltage values in the positive and negative voltage groups and the time interval between adjacent moments; calculates the time interval between the voltage data in the positive and negative voltage groups and the corresponding zero point moment based on the relative positions of the voltages in the positive and negative voltage groups in the rectangular coordinate system and in combination with the relevant theorem of similar triangles, which is denoted as the first time interval; determines the zero point moment between the voltages in the positive and negative voltage groups based on the proportional correction coefficient and the first time interval; calculates the working frequency at the current moment based on the time interval between two adjacent zero point moments. Through the real-time frequency detection algorithm, it can quickly and accurately detect the output frequency of in-vehicle distributed energy, avoid the delay problem caused by the need to collect two cycle bands in the traditional Fourier transform, improve the timeliness of grid connection testing, and provide reliable data support for grid connection operations; it can effectively prevent the misoperation of relay protection equipment and safety automatic devices caused by excessive frequency deviation, help reduce the occurrence of power grid faults, improve the stability and safety of the power grid, and thus ensure the reliable operation of the power grid; it helps to optimize the operation strategy of in-vehicle distributed energy and improve its support ability for the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0037] Figure 1 It is a flowchart of the steps of a grid connection test method for in-vehicle distributed energy based on modular assembly provided by an embodiment of the present application;

[0038] Figure 2 It is a schematic diagram of voltage data;

[0039] Figure 3 It is a schematic diagram of triangle similarity;

[0040] Figure 4 It is a local zero point diagram of the schematic diagram of triangle similarity. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] To further elaborate on the technical means and effects adopted by this application to achieve the intended invention purpose, the following describes in detail the specific implementation manner, structure, features, and effects of the on-vehicle distributed energy grid connection test method and device based on modular assembly proposed according to this application in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

[0043] The following specifically describes the specific solutions of the on-vehicle distributed energy grid connection test method and device based on modular assembly provided by this application in combination with the accompanying drawings.

[0044] Please refer to Figure 1 , which shows the step flowchart of the on-vehicle distributed energy grid connection test method provided by an embodiment of this application. The method includes the following steps:

[0045] Step S1, collect the voltage data of the on-vehicle distributed energy at each moment in real time.

[0046] For the modular assembled on-vehicle distributed energy, it includes a power distribution energy storage mobile detection vehicle module, a workstation module, a sensor module, a grid simulation power supply module, and a switch module. Among them, the power storage mobile detection vehicle module is used for grid connection testing; the workstation is used to collect the data collected by the sensors and transmit the data; the sensor module is used to collect data; the grid simulation power supply module is used to simulate the power supply; the switch module is used for the switching of each function.

[0047] Install an intelligent electricity meter at the output port of the on-vehicle distributed energy to collect the voltage data of the on-vehicle distributed energy in real time. For the collection of voltage data, preferably, in the embodiment of this application, the data collection frequency is set to 10 kHz. As other embodiments of this application, implementers can set the data collection frequency according to the actual situation. Arrange all the voltage data collected before the current moment in ascending order of the collection time, and the formed sequence is recorded as the frequency-identified voltage sequence. Denoise the frequency-identified voltage sequence through the SG filtering algorithm (Savitzky-Golay). Among them, the SG filtering algorithm is a well-known technology, and the specific process will not be elaborated. In other embodiments of this application, implementers can also use other denoising algorithms to denoise the frequency-identified voltage sequence.

[0048] Step S2, obtain each positive and negative voltage group in the voltage data based on the positive and negative conditions of the voltage at adjacent moments.

[0049] When detecting the frequency of in-vehicle distributed energy by Fourier transform, at least two cycles of discrete data are required, resulting in poor real-time performance. When quickly detecting the voltage frequency of in-vehicle distributed energy, generally, the time difference between the zero-crossing points of voltage data is detected to calculate the voltage frequency. For the detection of zero-crossing points, only less data is needed to calculate the zero position, thereby improving the detection efficiency and enhancing the real-time performance of detection. For the output voltage of electric energy, the voltage waveform of alternating current is a sine function. Since the collected data is discrete data, not continuous data. When the collected data coincides with the waveform period of alternating current, there are zero points for both discrete data and continuous data, as shown in Figure 2 a and b in Figure 2 . However, when collecting data, if it fails to synchronize with the waveform period of alternating current, there are still zero points for continuous data, but the collected discrete data may not have zero elements, as shown in c and d in

[0050] . Since during the process of collecting data, the position where the data is collected is not the initial point or half-period point of the sine function. Then it is very likely that the collected discrete data has no zero point, and the accuracy of the frequency obtained from the time difference between two non-zero points is relatively low. When determining the zero-crossing moment of voltage data, since the discrete data may not have a zero point, and the zero position is between two voltage data with adjacent data collection times but different positive and negative signs.

[0051] Therefore, taking the current moment as an example, first determine whether the voltage at the current moment is zero. If it is zero, then use the voltage data at the current moment as a zero point of the voltage frequency and continue data collection; if it is not zero, then determine whether the positive and negative signs of the voltage at the current moment and its previous moment are the same, that is, whether the voltages at the current moment and its previous moment are both positive voltages or both negative voltages. If the positive and negative signs of the voltage are the same, continue data collection. If the positive and negative signs of the voltage are different, then use the voltage at the current moment and its previous moment as a positive and negative voltage group to determine the zero position between the current moment and its previous moment and continue data collection. Among them, if the voltage data at the previous moment of the current moment has been determined as a zero point, only the zero point judgment is performed on the current moment, and no subsequent judgment related to the positive and negative voltage group is performed. Denote the positive and negative voltage group at the current moment as the first positive and negative voltage group.

[0052] Step S3, calculate the proportional correction coefficient of the positive and negative voltage group based on the difference between the voltage values in the positive and negative voltage group and the time interval between adjacent moments.

[0053] For the on-vehicle distributed energy, after being converted into alternating current by an inverter, the waveform of the continuous current is a sine function, and the sine function is rotationally symmetric at the periodic points and half-periodic points, that is, the intersection points of the sine function and the x-axis. Therefore, the positive and negative voltage group data can be regarded as data composed of two similar triangles. As Figure 3 shown. Figure 3 In it is shown that the coordinate point represents the voltage data point at the previous moment , and the corresponding voltage value is ; the coordinate point represents the point on the horizontal axis where the moment is located; the coordinate point represents the voltage data point at the current moment , and the corresponding voltage value is ; the coordinate point represents the point on the horizontal axis where the moment is located; the coordinate point represents the zero point between the moment and the moment

[0054] Figure 3 . This zero point is denoted as the first zero point. In triangle is approximated to triangle Figure 4 as shown. Therefore, the moment of the zero point can be calculated through the similarity ratio between the positive and negative voltage groups ( , ). However, triangle and triangle are only approximated and not similar. Therefore, before calculating through the similarity ratio, it is necessary to calculate the ratio correction coefficient. The expression of the ratio correction coefficient of the positive and negative voltage groups is:

[0055]

[0056] In the formula, represents the ratio correction coefficient of the first positive and negative voltage group; , respectively represent the normalized values of the voltage data at the previous moment and the current moment of the current moment; is the arcsine function; T represents the acquisition time interval between two adjacent voltage data. In the embodiments of the present application ; represents the exponential function with the natural constant as the base; represents the absolute value symbol. Among them, , are calculated respectively as , . In the formula, is the maximum value of the absolute value of historical voltage data.

[0057] Step S4: Based on the relative positions of the voltages in the positive and negative voltage groups in the rectangular coordinate system, and combining with the relevant theorems of similar triangles, calculate the time interval between the voltage data in the positive and negative voltage groups and the corresponding zero point moments, denoted as the first time interval.

[0058] Since triangle and triangle are only approximations and not similar to each other, there is a certain positional difference between the result of the zero point position and the true zero point position after the calculation process using the similarity theorem. Therefore, correction is performed through the angle ratio of the elements in the positive and negative voltage groups. At the same time, during the calculation process, the larger the sampling frequency, the smaller the time interval between two adjacent sampling data, and the higher the similarity degree between the triangles formed by the positive and negative voltage groups and the zero point. Therefore, the proportional correction coefficient is corrected by the time interval.

[0059] During the process of calculating the zero point moment, when using the similar triangle theorem for estimation, if triangle is similar to triangle , then there is:

[0060]

[0061]

[0062] In the formula, , respectively represent the voltages at the previous moment and the current moment of the current moment; represents the time interval between the previous moment of the current moment and the corresponding moment of the first zero point; represents the time interval between the current moment and the corresponding moment of the first zero point; T represents the acquisition time interval between two adjacent voltage data;

[0063] Furthermore, through the above formula, the expression for obtaining is: , where this expression is denoted as the first expression.

[0064] In the actual situation, since and are very likely not to be equal, therefore, and are not equal. So, triangle and triangle are not similar but only approximations. Therefore, the obtained The calculation result of the expression is not necessarily equal to the time interval between the previous moment of the current moment and the true zero moment in practice. Therefore, it is necessary to perform calibration before determining the moment of the true zero point.

[0065] Step S5: Determine the zero moment between the voltages in the positive and negative voltage groups based on the proportional correction coefficient and the first time interval.

[0066] Using the proportional correction coefficient of the positive and negative voltage groups and combining the distance between the zero moment and the moments of the voltage data in the positive and negative voltage groups, calculate the true zero moment. Among them, the true zero moment between the current moment and its previous moment is recorded as the current zero moment. Taking the current zero moment as an example, its expression is:

[0067]

[0068] In the formula, represents the current zero moment; represents the previous moment of the current moment; represents the proportional correction coefficient of the first positive and negative voltage group; represents the time interval between the previous moment and the moment corresponding to the first zero point calculated through the first expression, denoted as the first time interval. It should be noted that the calculation of the above expression is carried out on the premise that there is a zero moment between the current moment and its previous moment.

[0069] When the time interval between the zero moment and the moments of two elements in the positive and negative voltage groups is closer, the triangle and the triangle are more similar, and the proportional correction coefficient of the positive and negative voltage groups is closer to 1, and the influence on is smaller. The more accurate the true zero moment after calibration through the proportional correction coefficient, the more accurate the calculation of the output frequency of the vehicle-mounted distributed energy.

[0070] Furthermore, based on each positive and negative voltage group, using the same acquisition method as the current zero moment, obtain each zero moment.

[0071] Step S6: Calculate the working frequency of the current moment based on the time interval between two adjacent zero moments.

[0072] For the real-time frequency of the vehicle-mounted distributed energy, since the voltage waveform of the vehicle-mounted distributed energy is a sine function, it can be measured through the time interval between adjacent zero points. Based on the above analysis, calculate the working frequency of the current moment of the vehicle-mounted distributed energy, and the expression is:

[0073]

[0074] In the formula, represents the operating frequency at the current moment; , respectively represent the current zero point moment and the previous zero point moment; represents the period coefficient. Since is the time length of half a period of the voltage sine wave, therefore, the value of a is 2.

[0075] When the time interval between two adjacent zero points is smaller than the specified time interval , the operating frequency at the current moment is closer to the frequency specified by the state, and the operating state of the on-vehicle distributed energy is better. Among them, V represents the voltage frequency specified by the national power grid. Since the voltage frequency specified by the national power grid is 50, then V = 50 in this application; since the time interval between two zero points is half a period, therefore, V×2 is required.

[0076] Thus, through the above steps, the zero point moment of the voltage data can be calculated through two adjacent discrete data, and the operating frequency of the voltage data can be calculated using two adjacent zero point moments. Compared with the Fourier transform, the data used in this application is less, and the calculation amount is less than that of the Fourier transform, which can enhance the real-time performance of the on-vehicle distributed energy during the grid connection test.

[0077] Step S7, based on the operating frequency, analyze the grid connection state of the on-vehicle distributed energy and perform state adjustment.

[0078] For the operating frequency at the current moment, according to the standard in the national standard "GB / T 33593-2017", if the operating frequency at the current moment satisfies the condition or , then the on-vehicle distributed energy is in an abnormal operating state and it is necessary to immediately terminate the power supply of the on-vehicle distributed energy to the grid line. Among them, is used as the first frequency threshold, and is used as the second frequency threshold.

[0079] When When the on-vehicle distributed energy is used as the temporarily supplied energy, during the grid connection process, the working frequency of the on-vehicle distributed energy is affected by the grid load, and the stability of the working frequency will change. Therefore, the historical working frequency is used as the input of the CPS1 (Control Performance Standard 1) index formula, and the output is the CPS1 value when the on-vehicle distributed energy is working. If CPS1≥100%, it means that the dynamic regulation ability of the grid meets the requirements, the frequency recovery ability is good, and there is no need to adjust the current grid connection state. If CPS1<100%, it means that the dynamic regulation ability of the grid is insufficient, and it is necessary to further optimize the AGC control strategy and adjust the current grid connection state. Among them, the calculation of CPS1 and the process of optimizing the AGC control strategy therein are well-known technologies, and the specific process will not be elaborated here.

[0080] Based on the same inventive concept as the above method, the embodiment of the present application also provides an on-vehicle distributed energy grid connection test device based on modular assembly, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above methods of the on-vehicle distributed energy grid connection test method based on modular assembly.

[0081] To sum up, the embodiment of the present application provides an on-vehicle distributed energy grid connection test method based on modular assembly. By collecting the voltage data of the on-vehicle distributed energy at each moment in real time; obtaining each positive and negative voltage group in the voltage data based on the positive and negative conditions of the voltage at adjacent moments; calculating the proportional correction coefficient of the positive and negative voltage groups based on the difference between the voltage values in the positive and negative voltage groups and the time interval between adjacent moments; based on the relative positions of the voltages in the positive and negative voltage groups in the rectangular coordinate system, combining the relevant theorems of similar triangles, calculating the time interval between the voltage data in the positive and negative voltage groups and the corresponding zero point moment, denoted as the first time interval; determining the zero point moment between the voltages in the positive and negative voltage groups based on the proportional correction coefficient and the first time interval; calculating the working frequency at the current moment based on the time interval between adjacent two zero point moments. Through the real-time frequency detection algorithm, it can quickly and accurately detect the output frequency of the on-vehicle distributed energy, avoiding the delay problem caused by the traditional Fourier transform needing to collect two cycle bands, improving the timeliness of the grid connection test, providing reliable data support for the grid connection operation; it can effectively prevent the misoperation of relay protection equipment and safety automatic devices caused by excessive frequency deviation, help reduce the occurrence of power grid faults, improve the stability and safety of the power grid, and thus ensure the reliable operation of the power grid; it helps to optimize the operation strategy of the on-vehicle distributed energy and improve its support ability for the power grid.

[0082] It should be noted that: The above-mentioned sequence of embodiments of the present application is only for description and does not represent the superiority or inferiority of the embodiments. Moreover, the specific embodiments of the present application have been described above. Additionally, the processes depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0083] Each embodiment in the present application is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key point of each embodiment is to illustrate the differences from other embodiments.

[0084] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principles of the present application shall be included within the protection scope of the present application.

Claims

1. A vehicle-mounted distributed energy grid-connected testing method based on modular assembly, characterized in that: The method comprises the following steps: Real-time collection of voltage data of on-board distributed energy at all times; Based on the positive and negative voltage conditions at adjacent moments, each positive and negative voltage group in the voltage data is obtained; when the voltage at the current moment and the voltage at the previous moment form a positive and negative voltage group, the steps for obtaining the grid connection status and status adjustment of the on-board distributed energy are as follows: Calculating a proportional correction coefficient for the positive and negative voltage groups based on a difference between voltage values ​​in the positive and negative voltage groups and a time interval between adjacent moments; Based on the relative positions of the voltages in the positive and negative voltage groups in the rectangular coordinate system and in combination with the related theorem of similar triangles, the time interval between the voltage data in the positive and negative voltage groups and the corresponding zero point is calculated, which is recorded as the first time interval; Determine a zero point time between voltages in the positive and negative voltage groups based on the proportional correction coefficient and the first time interval; Calculate the working frequency at the current moment based on the time interval between two adjacent zero moments; Based on the working frequency, the grid-connected status of the on-board distributed energy is analyzed and the status is adjusted.

2. The vehicle-mounted distributed energy grid-connected testing method based on modular assembly as claimed in claim 1, characterized in that: The process of obtaining each positive and negative voltage group in the voltage data is as follows: If the voltage at each moment is not zero, then analyze whether the positive and negative signs of the voltage at each moment are the same as those at the previous moment. If they are different, then treat the voltage at each moment and the previous moment as a positive and negative voltage group.

3. The vehicle-mounted distributed energy grid-connected testing method based on modular assembly as claimed in claim 1, characterized in that: The process of obtaining the proportional correction coefficient of the positive and negative voltage groups is as follows: The proportional correction coefficient of the positive and negative voltage group formed by the voltage at the current moment and the voltage at the previous moment is recorded as , The expression is: , where; , Respectively represent the normalized values ​​of the voltage data at the moment before the current moment and the current moment; is an inverse sine function; T represents the acquisition time interval between two adjacent voltage data; Represents an exponential function with a natural constant as its base.

4. The vehicle-mounted distributed energy grid-connected testing method based on modular assembly as claimed in claim 1, characterized in that: The process of obtaining the time interval between the voltage data in the positive and negative voltage groups and the corresponding zero point is as follows: The voltage at the current moment and the previous moment are respectively recorded as and , and the current moment and the previous moment are respectively recorded as and ,Will and The zero point between the moments is recorded as the first zero point; wherein the voltage value of the first zero point is 0; based on and , and , and the first zero point, construct the triangle and triangle ; triangle and triangle When similar, based on the related theorem of similar triangles, the time interval between the previous moment of the current moment and the moment corresponding to the first zero point is obtained.

5. The vehicle-mounted distributed energy grid-connected testing method based on modular assembly as claimed in claim 4, characterized in that: The triangle and triangle The acquisition process is: The coordinate point As coordinate point , the coordinate point As coordinate point , take the first zero point as the coordinate point , we get the triangle ; Set the coordinate point As coordinate point , the coordinate point As coordinate point , we get the triangle .

6. The vehicle-mounted distributed energy grid-connected testing method based on modular assembly as claimed in claim 4, characterized in that: The process of obtaining the time interval between the moment before the current moment and the moment corresponding to the first zero point is: triangle With triangle When similar, there is: ,as well as ,in, Indicates the time interval between the moment before the current moment and the moment corresponding to the first zero point; represents the time interval between the current moment and the moment corresponding to the first zero point; T represents the acquisition time interval between two adjacent voltage data; but The expression is: .

7. The vehicle-mounted distributed energy grid-connected testing method based on modular assembly as claimed in claim 1, characterized in that: The expression of the zero point moment between the voltages in the positive and negative voltage groups is: , where Indicates the current zero time; Indicates the moment before the current moment; Indicates the proportional correction coefficient of the positive and negative voltage group formed by the voltage at the current moment and the voltage at the previous moment; Represents the first time interval between the moment before the current moment and the first zero point; wherein the current zero point moment is the real zero point moment between the current moment and the moment before it.

8. The vehicle-mounted distributed energy grid-connected testing method based on modular assembly as claimed in claim 7, characterized in that: The expression of the working frequency at the current moment is: , where Indicates the working frequency at the current moment; , Respectively represent the current zero time and the previous zero time; Indicates the preset period coefficient.

9. The vehicle-mounted distributed energy grid-connected testing method based on modular assembly as claimed in claim 1, characterized in that: The analysis of the grid-connected state of the vehicle-mounted distributed energy and the adjustment of the state are specifically as follows: If the current operating frequency is less than the preset first frequency threshold or greater than the preset second frequency threshold, the on-board distributed energy is in an abnormal operating state, and the on-board distributed energy is immediately stopped from transmitting power to the grid line; If the current operating frequency is greater than or equal to the preset first frequency threshold and less than or equal to the preset second frequency threshold, the historical operating frequency is used as the input of the CPS1 indicator formula, and the output is the CPS1 value when the on-board distributed energy is working. For the CPS1 value, if it is greater than or equal to 100%, the current grid-connected state is maintained; if it is less than 100%, the AGC control strategy is optimized and the current grid-connected state is adjusted.

10. A vehicle-mounted distributed energy grid-connected test device based on modular assembly, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 9 are implemented.

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