Charging pile metering performance evaluation method based on accumulated electric energy error

Abstract

The invention discloses a charging pile metering performance evaluation method based on accumulated electric energy errors, and relates to the field of charging pile metering performance evaluation. Or the opportunity of performing metering performance evaluation on the cluster charging piles is determined according to different metering display values of charging of the same automobile by each charging pile in the cluster charging piles; obtaining a high constant difference and a low constant difference according to a difference value between a checking accumulated value obtained by repeatedly monitoring the cluster charging pile for a plurality of times and a checked accumulated target value obtained by testing the same charging pile under the conditions of the same load at normal temperature, high temperature and low temperature; and determining that the metering performance of the charging pile belongs to any one of good metering performance, general metering performance and metering performance according to the relation in direct proportion to the checking accumulated value, the high constant difference and the low constant difference, so that the metering performance of the charging pile can be detected at a proper time.

Description

Technical Field

[0001] The present invention belongs to the technical field of charging pile metering performance evaluation, and specifically is a charging pile metering performance evaluation method based on cumulative electric energy error. Background Art

[0002] The patent with the publication number CN117250427A discloses an online monitoring device for the metering performance of a DC charging pile. The microprocessor module injects the shunt injection signal into the DC shunt, collects the AC / DC voltage and AC / DC current output by the DC shunt through the analog-to-digital conversion module, and then calculates the measured resistance value and DC power of the DC shunt according to the AC / DC voltage and AC / DC current output by the DC shunt, calculates the shunt error according to the measured resistance value and the default nominal resistance value, corrects the DC power of the DC shunt according to the shunt error, collects the electric energy pulse of the charging pile electric energy meter after the charging pile starts charging through the electric energy pulse input and output module, and calculates the metering error of the charging pile electric energy meter according to the corrected DC power and the electric energy pulse of the charging pile electric energy meter. The device solves the technical problem that the existing online monitoring method for the metering performance of DC charging piles is difficult to judge the failure or performance degradation of the shunt, resulting in inaccurate metering of DC charging piles.

[0003] However, for charging piles that have been put into use, when should the metering performance test be carried out so that the metering performance test can be carried out at a lower cost and at the same time be sufficiently accurate? This is a difficult problem. Based on this, a solution is provided. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art; To this end, the present invention proposes a charging pile metering performance evaluation method based on cumulative electric energy error, which specifically includes the following steps: According to the standard usage time of a cluster charging pile consisting of several charging piles of the same type in the same area, or the different metering display values ​​of each charging pile in the cluster charging pile for charging the same car, determine the metering performance evaluation of the cluster charging pile; According to the cumulative target values ​​representing the measurement errors obtained by repeatedly monitoring the cluster charging piles for several times, the verified cumulative value is determined; according to the difference between the cumulative target values ​​checked for the same charging pile under normal temperature, high temperature and low temperature, the high normal difference and the low normal difference are obtained; The error value is determined based on a relationship proportional to the approved cumulative value, the high normal error, and the low normal error. The metering performance of the charging pile is determined to be good metering performance, general metering performance, or good metering performance based on the error value.

[0005] Furthermore, the specific situation of determining the detection time point according to the standard usage time is as follows: A detection signal is generated when the standard time reaches 75%, and then the next cycle is determined based on the detection results. If the measurement performance is good, the next cycle will be carried out after another 25% of the standard usage time. If the measurement performance is average, the next cycle will be carried out after another 15% of the standard usage time. If the measurement performance is poor, a repair signal is generated.

[0006] Furthermore, different metering display values ​​of each charging pile in the cluster charging pile for charging the same car are determined as follows: The vehicle is locked according to the vehicle's VIN code, and then the same vehicle is obtained. When it is charged at any charging pile, the difference between the charged power and the power displayed by the charging pile is obtained when it is charged at other different charging piles, and several recurring differences are determined. A detection signal is generated according to the data distribution of the recurring differences; When the basic charging pile generates detection signals twice or more, a cluster detection signal is generated and the charging pile cluster needs to be tested for metering performance.

[0007] Further, the recurrence difference is determined by the following method, specifically: Recurring charging means that any identical vehicle is charged at different charging piles. Select a charging pile and obtain the vehicle in the recurring charging process including the charging pile and all its comparison charging piles; The charging amount of the charging pile is obtained, which is the percentage of electricity that the corresponding charging pile has charged for the vehicle, and the comparison charging amount of the comparison charging pile is obtained at the same time; then the charging power displayed by the charging pile and the comparison charging power displayed by the comparison charging pile are obtained; The formula is used to obtain the recurrence difference, which is: Reproduced difference = (charge amount / comparison charge amount) - (charged energy / comparison charged energy).

[0008] Furthermore, the comparison charging pile is another charging pile involved in the reproducing charging process, and specifically includes at least one comparison charging pile.

[0009] Furthermore, several recurring difference values ​​Fj are obtained, j=1, ..., m, and all recurring difference values ​​are automatically obtained with the help of the screening condition |Fj-U|≤X3, X3 is a preset value, Fj is screened, U is the mean of Fj, and the value of Fj that does not meet the screening condition is obtained, and then it is divided by m to obtain a value marked as an error ratio. When the error ratio exceeds the set value X4, a detection signal will be generated.

[0010] Furthermore, the specific steps for testing the cluster charging piles are: Obtain the real-time charging current and real-time charging voltage of the charging pile when charging the load, and calculate the cumulative target value based on the charging time; Then, several cumulative target values ​​are obtained based on the repeatability measurement, and the verified cumulative values ​​are determined based on the several cumulative target values. The high normal error and the low normal error are determined based on the verified cumulative values ​​of the same charging pile under normal temperature, high temperature and low temperature conditions, and the error value is calculated according to the formula. The specific formula is: Error value = 0.37*approved cumulative value + 0.63* (high abnormal error + low abnormal error).

[0011] Furthermore, when the error value does not exceed X2, it indicates that the metering performance of the charging pile is marked as good metering performance; when the error value exceeds X2 and is less than X5, the metering performance of the corresponding charging pile is marked as general metering performance; when the error value exceeds X5, the metering performance of the corresponding charging pile is marked as poor metering performance; X2 and X5 are both preset values.

[0012] Furthermore, the average of several cumulative target values ​​constitutes the approved cumulative value.

[0013] Furthermore, the method of determining the approved cumulative value through a number of cumulative target values ​​is as follows: The cumulative target value is marked as Li, i=1, ..., n, and then the mean value P of Li is automatically obtained. The aggregate value W of Li is calculated using the formula. The specific calculation formula is: ; When W does not exceed X1, the mean P is automatically marked as the approved cumulative value. If W exceeds X1, the corresponding Li value is automatically selected in the order of |Li-P|. Each time a value is selected, it is deleted. After deletion, the aggregation value W of the remaining Li is recalculated. If it still exceeds X1, Li continues to be selected and deleted in sequence until the W value does not exceed X1, and then the mean of the remaining Li is marked as the approved cumulative value.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present application determines the timing of metering performance evaluation of cluster charging piles according to the standard usage time of a cluster charging pile composed of several charging piles of the same type in the same area, or the different metering display values ​​of each charging pile in the cluster charging pile for charging the same car; and then obtains the high normal difference and the low normal difference according to the difference between the verified cumulative value obtained by repeatedly monitoring the cluster charging pile for several times and the cumulative target value checked for the same charging pile under normal temperature, high temperature and low temperature for the same load; According to the relationship proportional to the approved cumulative value, the high normal difference and the low normal difference, it is determined that the metering performance of the charging pile belongs to any one of good metering performance, general metering performance and good metering performance, so that the present application can perform metering performance detection on the charging pile at an appropriate time. The present invention is simple, effective and easy to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of the method used in the present invention; Figure 2 The present invention is a flow chart of determining the detection timing according to the recurrence difference. DETAILED DESCRIPTION

[0016] The technical scheme of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1-Figure 2 ,This application provides a charging pile metering performance evaluation method based on cumulative electric energy error; As an embodiment 1 of the present application, the method specifically includes the following steps: Step 1: Get the target charging pile to obtain the charging pile cluster. The specific acquisition method is: The charging piles of the same type in the same area are marked as cluster charging piles to obtain cluster charging piles; Step 2: Perform timing analysis for cluster charging piles. The specific method of timing analysis is as follows: For cluster charging piles, obtain the standard usage time set at the factory, generate a detection signal when the standard usage time reaches 75%, and then determine the next cycle based on the detection results. If the metering performance is good, the next cycle will be another 25% of the standard usage time. If the metering performance is average, the next cycle will be another 15% of the standard usage time. If the metering performance is poor, a repair signal will be generated. Step 3: Analyze the cluster charging piles. The specific analysis method is as follows: Select one charging pile from the cluster charging piles and obtain the cumulative target value of the charging pile. For the convenience of subsequent description, the cumulative power error is marked as the cumulative target value here; After the charging pile starts charging, the cumulative target value is obtained for the charging pile. The specific method is as follows: By means of a voltage sensor connected in parallel between the output end of the charging pile and the load, the real-time charging voltage of the charging pile is monitored when charging. The load mentioned here is an electric vehicle; With the help of a current sensor connected in series in the charging line, the real-time charging current of the charging pile is measured during charging; Then, based on the obtained real-time charging voltage and real-time charging current, combined with the charging time, the real-time electric energy consumed by the corresponding charging pile during charging is calculated according to the formula E=U*I*Δt, and marked as actual electric energy; Then obtain the charging power displayed by the charging pile itself and mark it as displayed power; The accumulated energy error is calculated according to the formula. The specific calculation formula is: Cumulative target value = (actual power - displayed power) / displayed power * 100%; Here, it is necessary to repeat the monitoring several times, that is, when several loads are charged at the same charging pile, repeat the measurement to obtain several cumulative target values, and then automatically add up the several cumulative target values, and the obtained value is marked as the approved cumulative value; The same process is performed on the remaining charging piles to obtain the cumulative target value of all charging piles; Then obtain the ambient temperature of the space where the charging pile is located, and perform different temperature difference analysis according to the ambient temperature. The specific method of temperature difference analysis is as follows: According to the temperature value, the administrator sets the normal temperature, high temperature and low temperature. The temperature ranges of normal temperature, high temperature and low temperature are preset values. Normally, the normal temperature mentioned here is 0℃ to 30℃, below 0℃ is low temperature, and above 30℃ is high temperature. For the convenience of description, the normal temperature, high temperature and low temperature are marked as temperature range 1, temperature range 2 and temperature range 3 in the following text; within the temperature ranges of temperature range 1, temperature range 2 and temperature range 3, the cumulative target values ​​are obtained respectively, which are marked as normal temperature target value, high temperature target value and low temperature target value respectively; The difference between the high temperature target value and the normal temperature target value is obtained and marked as high normal difference; The difference between the normal temperature target value and the low temperature target value is obtained and marked as low normal difference; Get the high and low normal differences of all charging piles; Step 4: Perform performance evaluation based on the verified cumulative value, high normal difference, and low normal difference of the charging pile. The specific method of performance evaluation is as follows: Select any charging pile and obtain its corresponding approved cumulative value, high normal difference, and low normal difference; Then calculate the error value according to the formula. The specific calculation method of the error value is: Error value = 0.37*approved cumulative value + 0.63* (high normal error + low normal error); When the error value does not exceed X2, it indicates that the metering performance of the charging pile is marked as good metering performance; when the error value exceeds X2 and is less than X5, the metering performance of the corresponding charging pile is marked as average metering performance; when the error value exceeds X5, the metering performance of the corresponding charging pile is marked as poor metering performance; X2 and X5 are both preset values.

[0018] The same analysis is performed on all other charging piles in the cluster to obtain the metering performance of all cluster charging piles.

[0019] As the second embodiment of the present invention, this embodiment is implemented on the basis of the first embodiment, and the difference is that this embodiment provides another specific method of timing analysis, and the specific method in this embodiment is: When an electric vehicle is charging, the electric vehicle's identification number will be automatically obtained. Specifically, after the charging pile establishes a connection with the vehicle, it will send a request to the vehicle's on-board communication unit through the communication protocol to obtain the vehicle's VIN code and identify the vehicle based on the VIN code; After several vehicles have charged the charging piles in the charging pile cluster, the charging collection will be repeated. The specific method of repeated charging collection is as follows: When any identical vehicle is charged at different charging piles, this process is called recurring charging, and the charging energy of the recurring charging is synchronously read by the charging pile itself; Then, a charging pile is selected to obtain the vehicle in the re-charging process including the charging pile, and all the comparison charging piles. The comparison charging pile is another charging pile involved in the re-charging process, which may include several comparison charging piles. The charging amount of the charging pile is obtained, which is the percentage of electricity that the corresponding charging pile has charged for the vehicle, and the comparison charging amount of the comparison charging pile is obtained at the same time; then the charging power displayed by the charging pile and the comparison charging power displayed by the comparison charging pile are obtained; The formula is used to obtain the recurrence difference, which is: Reproduced difference = (charge amount / comparison charge amount) - (charged power / comparison charged power); Several recurring differences can be obtained. These recurring differences may be compared with the same comparison charging pile or different comparison charging piles, but it is guaranteed that there is at least one for each comparison charging pile; The recurring difference is marked as Fj, j=1, ..., m, and then all the recurring differences are automatically obtained with the help of the screening condition |Fj-U|≤X3, X3 is a preset value, Fj is screened, where U is the mean of Fj, and the value of Fj that does not meet the screening condition is obtained, and then it is divided by m to obtain a value marked as an error ratio. When the error ratio exceeds the set value X4, a detection signal will be generated; Then select the remaining charging piles and perform the same processing on them to obtain whether a detection signal is generated. When two or more detection signals are generated, a cluster detection signal is generated, which means that the metering performance test of the charging pile cluster here needs to be performed; As the third embodiment of the present invention, this embodiment is implemented on the basis of the first embodiment, except that, in order to avoid an occasional error here, resulting in an excessively large approved cumulative value in the case of an average value, here, as another embodiment of the present application, an error analysis needs to be performed on the cumulative target value, and then the corresponding approved cumulative value is obtained; Then, error analysis is performed based on the cumulative target value. The specific method of error analysis is as follows: The cumulative target value is marked as Li, i=1, ..., n, and then the mean value P of Li is automatically obtained. The aggregate value W of Li is calculated using the formula. The specific calculation formula is: ; When W does not exceed X1, the mean value P is automatically marked as the approved cumulative value. If W exceeds the preset value X1, the corresponding Li value is automatically selected in the order of |Li-P|. Each time a value is selected, it is deleted. After deletion, the aggregate value W of the remaining Li is recalculated. If it still exceeds X1, Li is continuously selected and deleted in sequence until the W value does not exceed X1, and then the mean value of the remaining Li is marked as the approved cumulative value. The same process is performed on the cumulative target values ​​of the remaining charging piles; Of course, the present application may also implement the above three embodiments in combination.

[0020] The above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A charging pile metering performance evaluation method based on cumulative electric energy error, characterized in that: The method specifically comprises the following steps: According to the standard usage time of a cluster charging pile consisting of several charging piles of the same type in the same area, or the different metering display values ​​of each charging pile in the cluster charging pile for charging the same car, it is determined to start metering performance evaluation of the cluster charging piles; According to the cumulative target values ​​representing the measurement errors obtained by repeated monitoring of the cluster charging piles for several times, the verified cumulative value is determined; according to the difference between the cumulative target values ​​checked for the same charging pile under the preset temperature range 1, temperature range 2, and temperature range 3 for the same load, the high normal difference and the low normal difference are obtained; The error value is determined based on a relationship proportional to the approved cumulative value, the high normal error, and the low normal error. The metering performance of the charging pile is determined to be good, average, or poor based on the error value.

2. According to claim 1, a charging pile metering performance evaluation method based on cumulative electric energy error is characterized in that: The specific situation of determining the detection time point according to the standard usage time is as follows: A detection signal is generated when the standard time reaches 75%, and then the next cycle is determined based on the detection results. If the measurement performance is good, the next cycle will be carried out after another 25% of the standard usage time. If the measurement performance is average, the next cycle will be carried out after another 15% of the standard usage time. If the measurement performance is poor, a repair signal is generated.

3. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 1 is characterized in that: Different metering display values ​​for charging the same car at each charging pile in the cluster charging pile are used to determine the metering performance evaluation method for the cluster charging pile: The vehicle is locked according to the vehicle's VIN code, and then the same vehicle is obtained. When it is charged at any charging pile, the difference between the charged power and the power displayed by the charging pile is obtained when it is charged at other different charging piles, and several recurring differences are determined. A detection signal is generated according to the data distribution of the recurring differences; When the basic charging pile generates detection signals twice or more, a cluster detection signal is generated and the charging pile cluster needs to be tested for metering performance.

4. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 1 is characterized in that: The recurrence difference is determined in the following manner, specifically: Recurring charging means that any identical vehicle is charged at different charging piles. Select a charging pile and obtain the vehicle in the recurring charging process including the charging pile and all its comparison charging piles; The charging amount of the charging pile is obtained, which is the percentage of electricity that the corresponding charging pile has charged for the vehicle, and the comparison charging amount of the comparison charging pile is obtained at the same time; then the charging power displayed by the charging pile and the comparison charging power displayed by the comparison charging pile are obtained; The formula is used to obtain the recurrence difference, which is: Reproduced difference = (charge amount / comparison charge amount) - (charged energy / comparison charged energy).

5. A charging pile metering performance evaluation method based on cumulative electric energy error according to claim 4, characterized in that: The comparison charging pile is another charging pile involved in the reproducing charging process, and specifically includes at least one comparison charging pile.

6. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 1 is characterized in that: Get a number of recurring difference values ​​Fj, j=1, ..., m, and automatically get all the recurring difference values ​​with the help of the screening condition |Fj-U|≤X3, X3 is a preset value, Fj is screened, U is the mean of Fj, and the value of Fj that does not meet the screening condition is obtained, and then it is divided by m to get a value marked as the error ratio. When the error ratio exceeds the set value X4, a detection signal will be generated.

7. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 1 is characterized in that: The specific steps for testing cluster charging piles are as follows: Obtain the real-time charging current and real-time charging voltage of the charging pile when charging the load, and calculate the cumulative target value based on the charging time; Then, several cumulative target values ​​are obtained based on the repeatability measurement, and the verified cumulative values ​​are determined based on the several cumulative target values. The high constant error and the low constant error are determined based on the verified cumulative values ​​of the same charging pile in temperature range 1, temperature range 2, and temperature range 3, and the error value is calculated according to the formula. The specific formula is: Error value = 0.37*approved cumulative value + 0.63* (high abnormal error + low abnormal error).

8. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 1 is characterized in that: When the error value does not exceed X2, it indicates that the metering performance of the charging pile is marked as good metering performance; when the error value exceeds X2 and is less than X5, the metering performance of the corresponding charging pile is marked as average metering performance; when the error value exceeds X5, the metering performance of the corresponding charging pile is marked as poor metering performance; X2 and X5 are both preset values.

9. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 1 is characterized in that: The average of several cumulative target values ​​constitutes the approved cumulative value.

10. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 1 is characterized in that: The method of determining the approved cumulative value through several cumulative target values ​​is as follows: The cumulative target value is marked as Li, i=1, ..., n, and then the mean value P of Li is automatically obtained. The aggregate value W of Li is calculated using the formula. The specific calculation formula is: ； When W does not exceed X1, the mean P is automatically marked as the approved cumulative value. If W exceeds X1, the corresponding Li value is automatically selected in the order of |Li-P|. Each time a value is selected, it is deleted. After deletion, the aggregation value W of the remaining Li is recalculated. If it still exceeds X1, Li continues to be selected and deleted in sequence until the W value does not exceed X1, and then the mean of the remaining Li is marked as the approved cumulative value.

Images