A charging pile metering performance evaluation method based on cumulative electric energy error

Abstract

The present invention discloses a charging pile metering performance evaluation method based on cumulative electric energy error, which relates to the field of charging pile metering performance evaluation. The method determines the timing of metering performance evaluation of the cluster charging piles according to the standard usage time of a cluster charging pile composed of a plurality of charging piles of the same type in the same area, or the different metering display values ​​of each charging pile in the cluster charging piles for charging the same car. Then, a high constant error and a low constant error are obtained according to the difference between the approved cumulative value obtained by repeated monitoring of the cluster charging piles for several times and the cumulative target value checked when the same load is tested at normal temperature, high temperature and low temperature for the same charging pile. According to the relationship proportional to the approved cumulative value, the high constant error and the low constant error, it is determined whether the metering performance of the charging pile belongs to any one of good metering performance, general metering performance and metering performance, so that the present application can perform metering performance detection on the charging pile at an appropriate time.

Description

Technical Field

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

[0002] Patent publication number CN117250427A discloses an online monitoring device for the metering performance of DC charging piles. A microprocessor module injects a shunt injection signal into the DC shunt, and an analog-to-digital conversion module collects the AC / DC voltage and AC / DC current output by the DC shunt. The device then calculates the measured resistance and DC power of the DC shunt based on the AC / DC voltage and AC / DC current output by the DC shunt. The shunt error is calculated based on the measured resistance and the default nominal resistance. The DC power of the DC shunt is corrected based on the shunt error. After the charging pile starts charging, an energy pulse input and output module collects the energy pulses of the charging pile's energy meter. The microprocessor module calculates the metering error of the charging pile's energy meter based on the corrected DC power and the energy pulses of the charging pile's energy meter. This device addresses the technical issue of existing online monitoring methods for DC charging pile metering performance, which make it difficult to determine shunt failure or performance degradation, leading to inaccurate DC charging pile metering.

[0003] However, for charging piles that have been put into use, when should the metering performance test be carried out so as to achieve a lower cost and 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;

[0005] 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:

[0006] Based on the standard usage time of a cluster of charging piles 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 for charging the same car, determine the metering performance evaluation of the cluster charging piles;

[0007] The verified cumulative value is determined based on several cumulative target values ​​representing the measurement error obtained by repeated monitoring of the cluster charging piles several times; the high normal error and the low normal error are obtained based on the difference between the cumulative target values ​​checked for the same charging pile under normal temperature, high temperature and low temperature conditions with the same load;

[0008] The error value is determined based on a relationship that is 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 any one of good metering performance, general metering performance, and good metering performance based on the error value.

[0009] Furthermore, the specific circumstances for determining the detection time point according to the standard usage time are as follows:

[0010] 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.

[0011] Furthermore, the different metering display values ​​of each charging pile in the cluster charging pile for charging the same car are determined by the method of determining the metering performance evaluation of the cluster charging pile as follows:

[0012] The vehicle is locked according to its VIN code, and then the same vehicle is obtained. When charging at any charging pile, the difference between the charged power and the power displayed by the charging pile is obtained when the same vehicle is charged at different charging piles. Several recurring differences are determined, and a detection signal is generated based on the data distribution of the recurring differences.

[0013] When the basic charging pile generates a detection signal twice or more, a cluster detection signal is generated and the metering performance of the charging pile cluster must be tested.

[0014] Furthermore, the recurrence difference is determined by the following method, specifically:

[0015] Recurring charging means charging any identical vehicle at different charging stations. Select any charging station and obtain the vehicle in the recurring charging process including that charging station and all its comparison charging stations.

[0016] Obtain the charging amount of the charging pile, which is the percentage of electricity the corresponding charging pile has charged for the vehicle, and obtain the comparison charging amount of the comparison charging pile; then obtain the charging power displayed by the charging pile and the comparison charging power displayed by the comparison charging pile;

[0017] The formula is used to calculate the recurrence difference, which is:

[0018] Reproduced difference = (charge amount / compared charge amount) - (charged energy / compared charged energy).

[0019] Furthermore, the comparison charging pile is another charging pile involved in the reproducing charging process, and specifically includes at least one comparison charging pile.

[0020] 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 the error ratio. When the error ratio exceeds the set value X4, a detection signal will be generated.

[0021] Furthermore, the specific steps for testing cluster charging piles are as follows:

[0022] Obtain the real-time charging current and voltage of the charging pile when charging the load, and calculate the cumulative target value based on the charging time;

[0023] Then, a number of cumulative target values ​​are obtained based on the repeatability measurement. The verified cumulative value is determined based on the cumulative target values. The high and low normal errors are determined based on the verified cumulative values ​​of the same charging pile at normal temperature, high temperature, and low temperature. The error value is calculated according to the formula. The specific formula is:

[0024] Error value = 0.37*approved cumulative value + 0.63*(high normal error + low normal error).

[0025] 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 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.

[0026] Furthermore, the average of several cumulative target values ​​constitutes the approved cumulative value.

[0027] Furthermore, the method of determining the approved cumulative value through a number of cumulative target values ​​is as follows:

[0028] 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: ;

[0029] 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 aggregate 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.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] This application determines the timing of metering performance evaluation for cluster charging piles based on the standard usage duration of a cluster of charging piles of the same type located in the same area, or the different metering display values ​​of each charging pile within the cluster charging pile for the same vehicle. The application then determines the high and low normal deviations based on the difference between the verified cumulative value obtained by repeated monitoring of the cluster charging piles and the cumulative target value obtained by testing the same charging piles with the same load at normal, high, and low temperatures.

[0032] According to the relationship proportional to the approved cumulative value, the high normal difference and the low normal difference, the metering performance of the charging pile is determined to be 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

[0033] Figure 1 A flow chart of the method of the present invention;

[0034] Figure 2 This is a flow chart of the present invention for determining the detection timing based on the recurrence difference. DETAILED DESCRIPTION

[0035] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] See also Figure 1-Figure 2 ,This application provides a charging pile metering performance evaluation method based on cumulative electric energy error;

[0037] As embodiment 1 of the present application, the method specifically includes the following steps:

[0038] Step 1: Get the target charging pile and obtain the charging pile cluster. The specific acquisition method is as follows:

[0039] The charging piles of the same type in the same area are marked as cluster charging piles to obtain cluster charging piles;

[0040] Step 2: Conduct timing analysis for cluster charging piles. The specific methods for timing analysis are as follows:

[0041] For cluster charging piles, the factory-set standard usage time is obtained. A detection signal is generated when the standard usage time reaches 75%. The next cycle is then determined based on the detection results. If the metering performance is good, the next cycle is to last another 25% of the standard usage time. If the metering performance is average, the next cycle is to last another 15% of the standard usage time. If the metering performance is poor, a repair signal is generated.

[0042] Step 3: Analyze the cluster charging piles. The specific analysis method is as follows:

[0043] Select one charging pile from the cluster and obtain the cumulative target value of the charging pile. For the convenience of subsequent description, the cumulative energy error is marked as the cumulative target value.

[0044] After the charging pile starts charging, the cumulative target value is obtained for the charging pile. The specific method is as follows:

[0045] 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 during charging. The load mentioned here is an electric vehicle.

[0046] With the help of a current sensor connected in series in the charging circuit, the real-time charging current of the charging pile is measured during charging;

[0047] 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;

[0048] Then obtain the charging power displayed by the charging pile itself and mark it as displayed power;

[0049] Calculate the accumulated energy error according to the formula. The specific calculation formula is:

[0050] Cumulative target value = (actual power - displayed power) / displayed power * 100%;

[0051] Here, it is necessary to repeat the monitoring several times, that is, when several loads are charged at the same charging pile, repeat measurements are performed to obtain several cumulative target values, and then the several cumulative target values ​​are automatically added together, and the obtained value is marked as the approved cumulative value;

[0052] The same process is performed on the remaining charging piles to obtain the cumulative target value of all charging piles;

[0053] Then obtain the ambient temperature of the space where the charging pile is located, and perform different temperature difference analysis based on the ambient temperature. The specific method of temperature difference analysis is as follows:

[0054] 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, 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, their cumulative target values ​​are obtained respectively and marked as normal temperature target value, high temperature target value and low temperature target value respectively;

[0055] Obtain the difference between the high temperature target value and the normal temperature target value and mark it as high normal difference;

[0056] The difference between the normal temperature target value and the low temperature target value is obtained and marked as low normal difference;

[0057] Get the high and low normal differences of all charging piles;

[0058] Step 4: Perform performance evaluation based on the obtained charging pile's verified cumulative value, high normal difference, and low normal difference. The specific performance evaluation method is as follows:

[0059] Select any charging pile and obtain its corresponding approved cumulative value, high normal difference, and low normal difference;

[0060] Then calculate the error value according to the formula. The specific calculation method of the error value is:

[0061] Error value = 0.37*approved cumulative value + 0.63*(high normal error + low normal error);

[0062] 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.

[0063] The same analysis is performed on all other charging piles in the cluster to obtain the metering performance of all cluster charging piles.

[0064] As a second embodiment of the present invention, this embodiment is implemented on the basis of the first embodiment, except that this embodiment provides another specific method of timing analysis. The specific method in this embodiment is:

[0065] When an electric vehicle is charging, it will automatically obtain the electric vehicle's identification number. 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;

[0066] After a number of vehicles have charged the charging piles in the charging pile cluster, the charging data will be collected. The specific method of the collection is as follows:

[0067] When any identical vehicle is charged at different charging piles, this process is called replicated charging, and the charging energy is replicated synchronously. The charging energy is read by the charging pile itself.

[0068] Then, select any charging pile and obtain the vehicle in the re-charging process including the charging pile, and all its comparison charging piles. The comparison charging pile is another charging pile involved in the re-charging process, which may include several comparison charging piles.

[0069] Obtain the charging amount of the charging pile, which is the percentage of electricity the corresponding charging pile has charged for the vehicle, and obtain the comparison charging amount of the comparison charging pile; then obtain the charging power displayed by the charging pile and the comparison charging power displayed by the comparison charging pile;

[0070] The formula is used to calculate the recurrence difference, which is:

[0071] Recurrence difference = (charge amount / comparison charge amount) - (charged power / comparison charged power);

[0072] 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;

[0073] 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 divided by m to obtain a value marked as the error ratio. When the error ratio exceeds the set value X4, a detection signal will be generated;

[0074] Then select the remaining charging piles and perform the same process on them to determine whether a detection signal is generated. If two or more detection signals are generated, a cluster detection signal is generated, indicating that a metering performance test needs to be performed on the charging pile cluster at this location.

[0075] As a 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 causing the verified cumulative value to be too large in the average value case, as another embodiment of the present application, an error analysis is performed on the cumulative target value before the corresponding verified cumulative value is obtained;

[0076] Then, error analysis is performed based on the cumulative target value. The specific method of error analysis is as follows:

[0077] 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: ;

[0078] When W does not exceed X1, the mean 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 selected and deleted in sequence until the W value does not exceed X1. Then the mean of the remaining Li is marked as the approved cumulative value.

[0079] The same process is performed on the cumulative target values ​​of the remaining charging piles;

[0080] Of course, the present application can also implement the above three embodiments in combination.

[0081] The above embodiments are only used to illustrate the technical method of the present invention and are not intended to limit the present invention. 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: Determine to start metering performance evaluation of cluster charging piles based on the standard usage time 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 piles for the same car; The verified cumulative value is determined based on several cumulative target values ​​representing the measurement error obtained by repeated monitoring of the cluster charging piles. The high constant error and the low constant error are obtained based on the difference between the cumulative target values ​​checked for the same charging pile under the conditions of the same load in the preset temperature ranges 1, 2, and 3. The error value is determined based on a relationship that is proportional to the approved cumulative value, the high normal error, and the low normal error. Based on the error value, it is determined whether the metering performance of the charging pile is good, average, or poor.

2. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 1 is characterized in that: The specific circumstances for determining the detection time point based on the standard usage duration are 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: Each charging pile in the cluster charging pile displays different metering values ​​for charging the same car. The method for determining the metering performance evaluation of the cluster charging pile is as follows: The vehicle is locked according to its VIN code, and then the same vehicle is obtained. When charging at any charging pile, the difference between the charged power and the power displayed by the charging pile is obtained when the same vehicle is charged at different charging piles. Several recurring differences are determined, and a detection signal is generated based on the data distribution of the recurring differences. When the basic charging pile generates a detection signal twice or more, a cluster detection signal is generated and the metering performance of the charging pile cluster must be tested.

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 as follows: Recurring charging means charging any identical vehicle at different charging stations. Select any charging station and obtain the vehicle in the recurring charging process including that charging station and all its comparison charging stations. Obtain the charging amount of the charging pile, which is the percentage of electricity the corresponding charging pile has charged for the vehicle, and obtain the comparison charging amount of the comparison charging pile; then obtain the charging power displayed by the charging pile and the comparison charging power displayed by the comparison charging pile; The formula is used to calculate the recurrence difference, which is: Reproduced difference = (charge amount / compared charge amount) - (charged energy / compared charged energy).

5. The charging pile metering performance evaluation method based on cumulative electric energy error according to claim 4 is 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: A number of 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 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 voltage of the charging pile when charging the load, and calculate the cumulative target value based on the charging time; Then, a number of cumulative target values ​​are obtained based on the repeatability measurement. The verified cumulative value is determined based on the 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. The error value is calculated according to the formula. The specific formula is: Error value = 0.37*approved cumulative value + 0.63*(high normal error + low normal 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 aggregate 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.

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