A charging pile performance evaluation method and device

Abstract

The invention discloses a charging pile performance evaluation method and device, the method comprising: collecting data on evaluation indicators in a performance evaluation index system of a direct current charging pile and performing standardization processing to obtain score values ​​of various evaluation indicators; using multiple evaluation methods to determine the weights of various evaluation indicators, calculating the total score values ​​of various direct current charging piles under a single evaluation method according to the obtained weights, and calculating the total deviation between the total score values ​​of all direct current charging piles under each evaluation method combination according to a total score value matrix; establishing a combined evaluation model that maximizes the total deviation and solving it, normalizing the solution result to obtain the combined weight, and obtaining the combined evaluation value of the direct current charging pile according to the combined weight; calculating the gap sum according to the combined evaluation values ​​under different evaluation method combinations, determining the best evaluation method combination according to the gap sum, and taking the corresponding combined evaluation value as the final evaluation value; the method can evaluate the performance of the charging pile more accurately and reliably.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a charging pile performance evaluation method and device. Background Art

[0002] With the large-scale promotion of the electric vehicle industry, the number of existing charging piles can no longer meet the future use needs of electric vehicles that are about to be fully popularized. In the face of the current demand gap and shortcomings of charging facilities, the Chinese government has proposed to increase the construction of charging piles. Therefore, it is necessary to implement standardized and normalized management of electric vehicle charging equipment. The scientific management and comprehensive evaluation of existing charging piles have become increasingly prominent. In addition, since 2014, the country has fully opened up the pure electric vehicle infrastructure construction market and vigorously encouraged social capital to invest in charging pile construction. A large number of companies have sprung up. Among them are cross-border companies from the Internet, power grid companies and equipment suppliers, as well as companies such as production, sales, and construction of charging piles. Charging piles include many suppliers such as Tesla, TELD, Star Charging, and Potevio. The user experience of charging piles of major brands has also attracted much attention from consumers, so how to choose the charging pile with the best performance is a problem that should be paid attention to.

[0003] Patent document CN115146948A provides an electric vehicle charging pile health status assessment method based on a subjective and objective comprehensive fuzzy evaluation method, comprising the following steps: using a set value statistical analysis method to convert multiple qualitative indicator values ​​in the charging pile to obtain a score value; according to the charging pile mechanism, the subjective weight values ​​of the charging pile performance indicators are determined in turn according to the hierarchical analysis method; the score value is used to obtain the objective weight value of the corresponding performance indicator according to the entropy weight method; according to the additive integrated weighting method, the subjective weight value and the objective weight value are determined according to the relative importance of the indicator to determine the weight coefficient suitable for comprehensive evaluation; combined with the weight coefficient of the comprehensive evaluation, the fuzzy comprehensive evaluation method is used to finally obtain the health level of the charging pile.

[0004] The above method uses the analytic hierarchy process and the entropy weight method to add and obtain the evaluation weight coefficient, which ignores the fuzziness and randomness of indicator determination in the evaluation process and is too one-sided, resulting in low accuracy and reliability of the evaluation results. Summary of the invention

[0005] The present invention provides a charging pile performance evaluation method and device, which can effectively improve the accuracy and reliability of charging pile performance evaluation.

[0006] A charging pile performance evaluation method, comprising:

[0007] Establish a performance evaluation index system for DC charging piles;

[0008] Collecting data on the evaluation indicators in the performance evaluation indicator system of the DC charging pile and performing standardization processing to obtain the score value of each evaluation indicator;

[0009] Use multiple evaluation methods to determine the weights of various evaluation indicators, calculate the total score of each DC charging pile under a single evaluation method based on the obtained weights, and establish a total score matrix under different combinations of multiple evaluation methods;

[0010] According to the total score matrix, calculate the total deviation between the total score values ​​of all DC charging piles under each evaluation method combination;

[0011] Establishing and solving a combined evaluation model that maximizes the total deviation, normalizing the solution result to obtain a combined weight, and obtaining a combined evaluation value of the DC charging pile according to the combined weight;

[0012] According to the combined evaluation values ​​of the DC charging piles under different evaluation method combinations, the gap sum is calculated, and the best evaluation method combination is determined according to the gap sum, and the corresponding combined evaluation value is used as the final evaluation value.

[0013] Furthermore, the total deviation between the total score values ​​of the DC charging piles is calculated by the following formula:

[0014]

[0015] The combined evaluation model is expressed by the following formula:

[0016]

[0017] Where D is the total deviation between the total scores of DC charging piles, m is the number of types of DC charging piles, k is the number of evaluation methods, is the combined weight of the tth evaluation method, f it is the i-th DC charging pile in the evaluation method f t The score value under lt The evaluation method f is for the first type of DC charging pile t The following rating value.

[0018] Furthermore, the combined evaluation model is solved by constructing the Lagrange equation:

[0019]

[0020] in, is the combined weight of the tth evaluation method, f it is the i-th DC charging pile in the evaluation method f t The score value under lt The evaluation method f is for the first type of DC charging pilet The score value under , m is the number of types of DC charging piles, and k is the number of evaluation methods.

[0021] Furthermore, the combined evaluation value of the DC charging pile is:

[0022]

[0023] Among them, F i represents the combined evaluation value of the i-th charging pile, represents the normalized value of the combined weight, f i1 、f i2 、f i3 ,……f it It represents the total score obtained by each evaluation method for the i-th charging pile.

[0024] Furthermore, the difference and is calculated by the following formula:

[0025]

[0026] Among them, Q is the gap sum, pi represents the i-th combination evaluation value, and r is the total number of combination evaluation values.

[0027] Further, according to the gaps, the best combination of evaluation methods is determined, including:

[0028] Calculate the gap and average value under different numbers of combined evaluation methods, and take the number of combined evaluation methods with the highest gap and average value as the optimal number of combinations;

[0029] The combination evaluation method with the largest gap and the largest correspondence among the combination evaluation methods under the optimal number of combinations is taken as the best evaluation method combination.

[0030] Furthermore, the evaluation methods include analytic hierarchy process, entropy weight method, coefficient of variation method and CRITIC method.

[0031] Furthermore, the evaluation indicators in the performance evaluation index system include external structure performance evaluation indicators, electrical performance evaluation indicators, safety performance evaluation indicators and economic performance evaluation indicators; the external structure performance indicators include the degree of pile body loss, the failure rate of the human-computer interaction interface, the failure rate of the charging gun and the wear resistance of the pile cable; the electrical performance indicators include output voltage error, output current error, voltage regulation accuracy, current regulation accuracy, ripple factor, power factor and overall machine efficiency; the safety performance evaluation indicators include insulation performance, grounding protection, electric shock protection, emergency stop, over-temperature protection and safety warning; the economic performance evaluation indicators include charging life, charging cost, fault repair cost and charging efficiency.

[0032] A charging pile performance evaluation device applied to the above method comprises:

[0033] System establishment module, used to establish a performance evaluation index system for DC charging piles;

[0034] A scoring module is used to collect data on the evaluation indicators in the performance evaluation indicator system of the DC charging pile and perform standardized processing to obtain the scoring value of each evaluation indicator;

[0035] The matrix calculation module is used to determine the weight of each indicator data using multiple evaluation methods, calculate the total score of each DC charging pile under a single evaluation method according to the obtained weight, and establish a total score matrix under different combinations of multiple evaluation methods;

[0036] A deviation calculation module, used to calculate the total deviation between the total score values ​​of all DC charging piles under each evaluation method combination according to the total score value matrix;

[0037] A combination evaluation module, used to establish and solve a combination evaluation model that maximizes the total deviation, normalize the solution result to obtain a combination weight, and obtain a combination evaluation value of the DC charging pile according to the combination weight;

[0038] The optimal evaluation module is used to calculate the gap sum according to the combined evaluation values ​​of the DC charging piles under different evaluation method combinations, determine the best evaluation method combination according to the gap sum, and use the corresponding combined evaluation value as the final evaluation value.

[0039] The charging pile performance evaluation method and device provided by the present invention have at least the following beneficial effects:

[0040] By analyzing the combined weighting method based on maximizing the deviation, the idea of ​​maximizing the deviation is applied to the combination of the evaluation values ​​obtained by each single evaluation method. After reasonably allocating the contribution of each evaluation method, the best combination of evaluation methods is determined according to the gaps under different combinations of evaluation methods and the discreteness of the evaluation result values ​​of the test combination evaluation method. The combined evaluation value corresponding to the best combination of evaluation methods is used as the final evaluation value, making the evaluation result more accurate and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 A flowchart of an embodiment of the charging pile performance evaluation method provided by the present invention.

[0042] Figure 2 A schematic diagram of an embodiment of a performance evaluation index system in the charging pile performance evaluation method provided by the present invention.

[0043] Figure 3 A schematic structural diagram of an embodiment of a charging pile performance evaluation device provided by the present invention. DETAILED DESCRIPTION

[0044] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0045] refer to Figure 1 In some embodiments, a charging pile performance evaluation method is provided, comprising:

[0046] S1. Establish a performance evaluation index system for DC charging piles;

[0047] S2. Collecting data on the evaluation indicators in the performance evaluation indicator system of the DC charging pile and performing standardization processing to obtain the score value of each evaluation indicator;

[0048] S3. Determine the weight of each evaluation index using multiple evaluation methods, calculate the total score of each DC charging pile under a single evaluation method based on the obtained weight, and establish a total score matrix under different combinations of multiple evaluation methods;

[0049] S4. Calculate the total deviation between the total score values ​​of all DC charging piles under each evaluation method combination according to the total score value matrix;

[0050] S5. Establish and solve a combined evaluation model that maximizes the total deviation, normalize the solution result to obtain a combined weight, and obtain a combined evaluation value of the DC charging pile according to the combined weight;

[0051] S6. Calculate the sum of the gaps according to the combined evaluation values ​​of the DC charging piles under different evaluation method combinations, determine the best evaluation method combination according to the sum of the gaps, and use the corresponding combined evaluation value as the final evaluation value.

[0052] Specifically, refer to Figure 2 In step S1, the evaluation indicators in the performance evaluation index system include external structure performance evaluation indicators, electrical performance evaluation indicators, safety performance evaluation indicators and economic performance evaluation indicators; the external structure performance indicators include the degree of pile body loss, the failure rate of the human-machine interaction interface, the failure rate of the charging gun and the wear resistance of the pile cable; the electrical performance indicators include output voltage error, output current error, voltage regulation accuracy, current regulation accuracy, ripple factor, power factor and overall efficiency; the safety performance evaluation indicators include insulation performance, grounding protection, electric shock protection, emergency stop, over-temperature protection and safety warning; the economic performance evaluation indicators include charging life, charging cost, fault repair cost and charging efficiency.

[0053] Specifically, the performance evaluation index system is the basis and important premise for the study of comprehensive evaluation issues. In the process of establishing a charging pile performance evaluation index system and selecting evaluation indicators, basic principles such as scientific principles, comprehensive principles, independence principles, operability principles, and comparability principles should be followed. In this embodiment, the relevant national standards for DC charging piles are first summarized, the unique properties of DC charging piles are analyzed, and the key indicators for DC charging pile testing are sorted out. Then, in response to existing problems in the actual use of DC charging piles, the root causes of the problems are analyzed, the test indicators are further improved, and a comprehensive DC charging pile performance evaluation index system is established. Figure 2 As shown in the figure, the index system consists of primary indicators such as external structural performance, electrical performance, safety performance and economic performance. Among them, the secondary indicators under the external structural performance include the degree of pile body loss, human-machine interface failure rate, charging gun failure rate and pile cable wear resistance; the secondary indicators under the electrical performance include output voltage error, output current error, voltage regulation amplitude, current regulation accuracy, ripple coefficient, power factor and overall efficiency; the secondary indicators under the safety performance include insulation performance, grounding protection, electric shock protection, emergency shutdown, over-temperature protection and safety warning; the secondary indicators under the economic performance include charger life, charging cost, fault repair cost and charging efficiency.

[0054] The performance of electric vehicle DC charging piles includes many aspects such as external structural performance, electrical performance, safety performance, economic performance, etc. Its evaluation system must be a complex multi-index evaluation system, which includes both quantitative and qualitative indicators. When solving such multi-index comprehensive evaluation problems, using only a single weighting method will make the weighting of each evaluation index too one-sided, and ignore the ambiguity and randomness of the index determination during the evaluation process. Therefore, in this embodiment, multiple evaluation methods are used and the best evaluation method combination calculated to determine the final evaluation value.

[0055] Furthermore, in step S2, the data of each evaluation index of the charging pile is standardized, and the electrical performance indicators selected in the index system are all quantitative indicators, which can be divided into positive indicators and negative indicators. Among them, the output voltage / current error, ripple coefficient, current imbalance, voltage / current stabilization accuracy are all negative indicators, and the smaller the index value, the better; the power factor and overall efficiency are positive indicators, and the larger the index value, the better. Through the range change method, the quantitative index measurement value can be converted into an index score value between 0 and 10.

[0056] The external structural performance, safety performance and economic performance of charging piles are all qualitative indicators that cannot be directly measured by instruments. Experts or practitioners are required to conduct on-site assessments to give scoring values.

[0057] Furthermore, in step S3, a plurality of evaluation methods are used to determine the weights of various evaluation indicators, wherein the plurality of evaluation methods include but are not limited to the analytic hierarchy process, the entropy weight method, the coefficient of variation method, the CRITIC method, and the like.

[0058] Specifically, the analytic hierarchy process is a comprehensive evaluation method that effectively combines quantitative analysis with qualitative analysis. It uses a hierarchical structure model of the research object and integrates expert opinions to calculate the weights. The specific steps for determining each weight using the interval analytic hierarchy process are as follows:

[0059] First, we obtain the expert scores on various evaluation indicators of charging piles of different brands through questionnaires, and construct the judgment matrix A by comparing the scores of each indicator pairwise.

[0060] Then let A - =(a ij - ) N*N , A + =(a ij + ) N*N , A - A is the matrix composed of the lower limits of the intervals in the judgment matrix. + is the matrix composed of the upper limits of the intervals in the judgment matrix, a ij is the interval number; a ij - Refers to all the numbers in the A-matrix, a ij + It refers to A + all the numbers in the matrix; N is the order; then A=[A - ,A + ] Use the characteristic root method to obtain the matrix A - and A + The weight vector of the largest eigenvalue is the required weight vector, which are x - =(x 1 - ,x 2 - ,x 3 - ……x N - ), x + =(x 1 + ,x 2 + ,x 3 + ……x N + ).

[0061] Furthermore, the consistency test of indicators at the same level is carried out:

[0062]

[0063] If k≤1, β≥1, it is considered that the test has passed and the matrix consistency is good; if k>1, β<1, it is considered that the test has not passed and the consistency is poor.

[0064] If the consistency test is passed, it means that the judgment matrix is ​​reasonable, and finally the weight value of each evaluation index is obtained through the formula:

[0065]

[0066] Where k is A + The corresponding intermediate coefficient of the eigenvalue; β is A - The corresponding intermediate coefficient of the eigenvalue; x - A - The corresponding weight vector; x + A + The corresponding weight vector, ω (1) is the weight value of each evaluation index obtained by analytic hierarchy process.

[0067] The entropy weight method is an objective weighting method that can effectively reduce the interference of human factors and ensure that the evaluation results will not be affected by subjective factors. The steps for calculating the weights using the entropy weight method are:

[0068] The entropy weight is solved by using the difference in the scoring values ​​of the charging pile indicators of each brand after standardization, and the information entropy of the jth evaluation indicator of the i-th brand of DC charging pile is calculated:

[0069]

[0070] Where:

[0071] Among them, E ij represents the information entropy of the jth evaluation index of the i-th DC charging pile, α is the coefficient, which is a constant, and p ij (k) represents the characteristic weight or contribution of the jth evaluation index of the i-th DC charging pile, lnp ij (k) refers to p ij The natural logarithm of (k) represents the amount of information contained in the jth evaluation index of the i-th DC charging pile. ij The larger (k) is, the higher the contribution, the greater the probability of occurrence, and the amount of information contained is lnp ij (k) is smaller, K=m, representing the number of types of DC charging piles, α=1 / lnm.

[0072] The weight values ​​of each indicator are then corrected through the formula, making the indicator weight values ​​more accurate:

[0073]

[0074] Among them, ω (2) is the weight value of each evaluation index obtained by the entropy weight method, and n represents the number of evaluation indicators.

[0075] The coefficient of variation method uses the information contained in each evaluation indicator to calculate the weight value of each evaluation indicator. The idea of ​​this method is: in the established performance evaluation indicator system, the greater the difference in the value of the evaluation indicator, the more difficult it is to achieve the indicator, and it can better reflect the gap between the evaluated units.

[0076] The coefficient of variation of each indicator is calculated using the formula to indicate the difference in the values ​​of each indicator:

[0077] v i =δ i / x i ,i=1,2,…,n; (7)

[0078] In the formula, v i It is called the coefficient of variation, also called the standard deviation coefficient, δ i is the standard deviation of the evaluation index data, and xi is the mean of the evaluation index data.

[0079] Calculate the weight of each indicator of the charging pile according to the following formula ω (3) :

[0080]

[0081] Among them, ω (3) is the weight value of each evaluation index obtained by the coefficient of variation method.

[0082] The CRITIC method is a method for determining weights based on the correlation of indicators. The basic principle of determining indicator weights in this method is to determine them through the intra-indicator variability and inter-indicator conflict. The intra-indicator variability is based on the same indicator, and the degree of difference between the data of each evaluation object of the same indicator is measured by using the standard deviation. The inter-indicator conflict is based on different indicators, and the degree of difference between different indicators is extended based on the correlation coefficient between indicators. The basic steps of using the CRITIC method are:

[0083] (1) Calculate the variability within each evaluation indicator:

[0084]

[0085] Among them, α j represents the standard deviation, xij represents the score value of the jth evaluation index of the i-th DC charging pile, Represents the mean value of the jth evaluation index.

[0086] (2) Calculate the conflict between evaluation indicators:

[0087]

[0088] Among them, Pj represents the conflict of evaluation index j, q tj represents the correlation coefficient between the t-th evaluation index and the j-th evaluation index, xit represents the score value of the t-th evaluation index of the i-th DC charging pile, represents the mean value of the jth evaluation index, It represents the mean of the tth evaluation index, and n represents the number of evaluation indicators.

[0089] (3) Calculate the information amount of each evaluation index:

[0090] S j =α j *P j ; (12)

[0091] Among them, Sj represents the information content of evaluation index j.

[0092] (4) Calculate the weight of each indicator:

[0093]

[0094] Among them, ω (4) is the weight value of each evaluation index obtained by the CRITIC method.

[0095] After the weights determined by the above multiple evaluation methods, the total score of each DC charging pile under a single evaluation method is obtained, and the total score matrix of multiple evaluation methods under each combination can be established. If the i-th DC charging pile is t The total score under it , then the total score matrix under various evaluation methods is F = (f it ) m*k , where m is the number of types or brands of direct charging piles, i = 1, 2, 3, ... m, and k is the number of evaluation methods, t = 1, 2, 3, ... k.

[0096] Further, in step S4, it is assumed that the DC charging pile i and the DC charging pile l are evaluated in the evaluation method f t The deviation between the total score values ​​is:

[0097]

[0098] Where k is the number of evaluation methods, D itl DC charging pile i and DC charging pile l in evaluation method f tThe difference between the total score values, f it is the i-th DC charging pile in the evaluation method f t The score value under lt The evaluation method f is for the first type of DC charging pile t The rating value below, is the combined weight of the tth evaluation method.

[0099] The total deviation between the total score values ​​of DC charging piles is calculated by the following formula:

[0100]

[0101] Where D is the total deviation between the total scores of DC charging piles, m is the number of types of DC charging piles, k is the number of evaluation methods, is the combined weight of the tth evaluation method, f it is the i-th DC charging pile in the evaluation method f t The score value under lt The evaluation method f is for the first type of DC charging pile t The following rating value.

[0102] The combined evaluation model is expressed by the following formula:

[0103]

[0104] The combined evaluation model is solved by constructing the Lagrange equation:

[0105]

[0106] in, is the combined weight of the tth evaluation method, f it is the i-th DC charging pile in the evaluation method f t The score value under lt The evaluation method f is for the first type of DC charging pile t The score value under , m is the number of types of DC charging piles, and k is the number of evaluation methods.

[0107] Combined weight for the tth evaluation method Normalization is performed to obtain

[0108] After the above calculation, the combined evaluation value of the DC charging pile is:

[0109]

[0110] Among them, F i represents the combined evaluation value of the i-th charging pile, represents the normalized value of the combined weight, f i1 、f i2 、f i3 ,……f it It represents the total score obtained by each evaluation method for the i-th charging pile.

[0111] Furthermore, in order to screen out the best combination of evaluation methods, in step S6, the sum of the gaps is calculated according to the combined evaluation values ​​of the DC charging piles under the above-mentioned different evaluation method combinations, and the sum of the gaps is calculated by the following formula:

[0112]

[0113] Among them, Q is the gap sum, pi represents the i-th combination evaluation value, and r is the total number of combination evaluation values.

[0114] The purpose of gap and Q is to test the dispersion of the evaluation result values ​​of the combined evaluation method. The larger the value, the greater the dispersion of the evaluation result values ​​of the combined evaluation method, and the closer the combined evaluation method is to the combination with the optimal dispersion of the evaluation result values.

[0115] Further, according to the gaps, the best combination of evaluation methods is determined, including:

[0116] S61, calculating the gap and average value under different numbers of combined evaluation methods, and taking the number of combined evaluation methods corresponding to the highest gap and average value as the optimal number of combinations;

[0117] S62. The combination evaluation method with the largest gap and the largest correspondence among the combination evaluation methods under the optimal number of combinations is taken as the best evaluation method combination.

[0118] The following further illustrates the principle of the optimal combination of evaluation methods through specific application scenarios.

[0119] Assuming that the above calculations are performed on various DC charging pile brands through different combinations of a, tomography analysis method, b, entropy weight method, c, coefficient of variation method, and d, CRITIC method, the results of the gap and are obtained are as follows:

[0120]

[0121]

[0122] Table 1

[0123] It can be seen from Table 1 that under the combination of three evaluation methods and four evaluation methods, the gap and average value of the three combinations are the highest, which is 4.3115. Therefore, the optimal number of combinations is determined to be three. Furthermore, under the combination of three evaluation methods, the gap and average value of the tomography analysis method, entropy weight method, and coefficient of variation method are the largest, which is 5.2196. Therefore, this combination is finally used as the best evaluation method combination.

[0124] The charging pile performance evaluation method provided in the above embodiment has at least the following beneficial effects:

[0125] By analyzing the combined weighting method based on maximizing the deviation, the idea of ​​maximizing the deviation is applied to the combination of the evaluation values ​​obtained by each single evaluation method. After reasonably allocating the contribution of each evaluation method, the best combination of evaluation methods is determined according to the gaps under different combinations of evaluation methods and the discreteness of the evaluation result values ​​of the test combination evaluation method. The combined evaluation value corresponding to the best combination of evaluation methods is used as the final evaluation value, making the evaluation result more accurate and reliable.

[0126] refer to Figure 3 In some embodiments, a charging pile performance evaluation device applied to the above method is provided, comprising:

[0127] A system establishment module 201 is used to establish a performance evaluation index system for DC charging piles;

[0128] Scoring module 202, used to collect data on evaluation indicators in the performance evaluation indicator system of the DC charging pile and perform standardization processing to obtain scoring values ​​for each evaluation indicator;

[0129] The matrix calculation module 203 is used to determine the weights of various indicator data using multiple evaluation methods, calculate the total score of each DC charging pile under a single evaluation method according to the obtained weights, and establish a total score matrix under different combinations of multiple evaluation methods;

[0130] The deviation calculation module 204 is used to calculate the total deviation between the total score values ​​of all DC charging piles under each evaluation method combination according to the total score value matrix;

[0131] A combination evaluation module 205 is used to establish and solve a combination evaluation model that maximizes the total deviation, normalize the solution result to obtain a combination weight, and obtain a combination evaluation value of the DC charging pile according to the combination weight;

[0132] The optimal evaluation module 206 is used to calculate the gap sum according to the combined evaluation values ​​of the DC charging piles under different evaluation method combinations, determine the best evaluation method combination according to the gap sum, and use the corresponding combined evaluation value as the final evaluation value.

[0133] Specifically, the performance evaluation index system established by the system establishment module 201 is as follows: Figure 2 shown.

[0134] Furthermore, the deviation calculation module 204 calculates the total deviation between the total score values ​​of the DC charging piles through formula (15).

[0135] Furthermore, the combined evaluation model established by the combined evaluation module 205 is shown in formula (16), and the constructed Lagrange equation is shown in formula (17). The combined evaluation value is calculated by formula (18).

[0136] Furthermore, the optimal evaluation module 206 calculates the gap sum according to formula (19), and calculates the gap sum average value under different numbers of combined evaluation methods, and takes the number of combined evaluation methods corresponding to the highest gap sum average value as the optimal number of combinations; and takes the combined evaluation method corresponding to the largest gap sum among the combined evaluation methods under the optimal number of combinations as the best evaluation method combination.

[0137] The charging pile performance evaluation device provided in the above embodiment has at least the following beneficial effects:

[0138] By analyzing the combined weighting method based on maximizing the deviation, the idea of ​​maximizing the deviation is applied to the combination of the evaluation values ​​obtained by each single evaluation method. After reasonably allocating the contribution of each evaluation method, the best combination of evaluation methods is determined according to the gaps under different combinations of evaluation methods and the discreteness of the evaluation result values ​​of the test combination evaluation method. The combined evaluation value corresponding to the best combination of evaluation methods is used as the final evaluation value, making the evaluation result more accurate and reliable.

[0139] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A charging pile performance evaluation method, characterized in that: include: Establish a performance evaluation index system for DC charging piles; Collecting data on the evaluation indicators in the performance evaluation indicator system of the DC charging pile and performing standardization processing to obtain the score value of each evaluation indicator; Use multiple evaluation methods to determine the weights of various evaluation indicators, calculate the total score of each DC charging pile under a single evaluation method based on the obtained weights, and establish a total score matrix under different combinations of multiple evaluation methods; According to the total score matrix, calculate the total deviation between the total score values ​​of all DC charging piles under each evaluation method combination; Establishing and solving a combined evaluation model that maximizes the total deviation, normalizing the solution result to obtain a combined weight, and obtaining a combined evaluation value of the DC charging pile according to the combined weight; Calculate the sum of the gaps according to the combined evaluation values ​​of the DC charging piles under different evaluation method combinations, determine the best evaluation method combination according to the sum of the gaps, and use the corresponding combined evaluation value as the final evaluation value; The difference and are calculated by the following formula: Among them, Q is the gap sum, pi represents the i-th combination evaluation value, and r is the total number of combination evaluation values; Based on the gaps identified, the best combination of evaluation methods was determined, including: Calculate the gap and average value under different numbers of combined evaluation methods, and take the number of combined evaluation methods with the highest gap and average value as the optimal number of combinations; The combination evaluation method with the largest gap and the largest correspondence among the combination evaluation methods under the optimal number of combinations is taken as the best evaluation method combination.

2. The method according to claim 1, characterized in that The total deviation between the total score values ​​of DC charging piles is calculated by the following formula: The combined evaluation model is expressed by the following formula: Where D is the total deviation between the total scores of DC charging piles, m is the number of types of DC charging piles, k is the number of evaluation methods, is the combined weight of the tth evaluation method, f it is the i-th DC charging pile in the evaluation method f t The score value under lt The evaluation method f is for the first type of DC charging pile t The following rating value.

3. The method according to claim 2, characterized in that The combined evaluation model is solved by constructing the Lagrange equation: in, is the combined weight of the tth evaluation method, f it is the i-th DC charging pile in the evaluation method f t The score value under lt The evaluation method f is for the first type of DC charging pile t The score value under , m is the number of types of DC charging piles, and k is the number of evaluation methods.

4. The method according to claim 3, characterized in that The combined evaluation value of the DC charging pile is: Among them, F i represents the combined evaluation value of the i-th charging pile, represents the normalized value of the combined weight, f i1 、f i2 、f i3 ,……f it It represents the total score obtained by each evaluation method for the i-th charging pile.

5. The method according to any one of claims 1 to 4, characterized in that: The evaluation methods include analytic hierarchy process, entropy weight method, coefficient of variation method and CRITIC method.

6. The method according to any one of claims 1 to 4, characterized in that: The evaluation indicators in the performance evaluation index system include external structure performance evaluation indicators, electrical performance evaluation indicators, safety performance evaluation indicators and economic performance evaluation indicators; the external structure performance indicators include the degree of pile body loss, human-machine interface failure rate, charging gun failure rate and pile cable wear resistance; the electrical performance evaluation indicators include output voltage error, output current error, voltage regulation accuracy, current regulation accuracy, ripple factor, power factor and overall efficiency; the safety performance evaluation indicators include insulation performance, grounding protection, electric shock protection, emergency stop, over-temperature protection and safety warning; The economic performance evaluation indicators include charging life, charging cost, fault repair cost and charging efficiency.

7. A charging pile performance evaluation device applied to the method according to any one of claims 1 to 6, characterized in that: include: System establishment module, used to establish a performance evaluation index system for DC charging piles; A scoring module is used to collect data on the evaluation indicators in the performance evaluation indicator system of the DC charging pile and perform standardized processing to obtain the scoring value of each evaluation indicator; The matrix calculation module is used to determine the weights of various indicator data using multiple evaluation methods, calculate the total score of each DC charging pile under a single evaluation method according to the obtained weights, and establish a total score matrix under different combinations of multiple evaluation methods; A deviation calculation module, used to calculate the total deviation between the total score values ​​of all DC charging piles under each evaluation method combination according to the total score value matrix; A combination evaluation module, used to establish and solve a combination evaluation model that maximizes the total deviation, normalize the solution result to obtain a combination weight, and obtain a combination evaluation value of the DC charging pile according to the combination weight; The optimal evaluation module is used to calculate the gap sum according to the combined evaluation values ​​of the DC charging piles under different evaluation method combinations, determine the best evaluation method combination according to the gap sum, and use the corresponding combined evaluation value as the final evaluation value.

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