Charging pile thermal derating method and storage medium

Abstract

The invention provides a charging pile thermal derating method and a storage medium, and the method comprises the steps: querying a strategy table according to a current charging current, and determining a current derating gear and a maximum allowable temperature; when the average temperature of the internal environment of the current charging pile is greater than the maximum allowable temperature corresponding to the current derating gear and the temperature is in a rising trend, executing downshift operation and controlling the charging pile to allow maximum current output; wherein the judgment condition that the temperature is in the rising trend is that the temperature change rate is greater than a first temperature change rate threshold value; or, the average temperature of the internal environment of the current charging pile is larger than the first temperature threshold value, the average temperature of the internal environment of the current charging pile is larger than the temperature value corresponding to the last sampling moment, and the internal environment temperature of the charging pile corresponding to the current sampling moment is larger than the temperature value corresponding to the last sampling moment. The technical problems of how to improve the charging efficiency of the charging pile and how to protect equipment are solved.

Description

Technical Field

[0001] The present application belongs to the field of charging technology and relates to a charging pile thermal derating method and a storage medium. Background Art

[0002] During the actual operation of the charging pile, its internal temperature will increase with the increase of charging current and the rise of ambient temperature. When the internal temperature exceeds a certain limit, key components inside the charging pile (such as power electronic components, control modules, etc.) will fail due to overheating, which may cause safety hazards in serious cases. In order to avoid abnormal overheating of internal components and ensure the stable operation of the charging pile, it is necessary to ensure that the internal temperature does not exceed its limit and that key components are used within their operating temperature range.

[0003] In order to solve the problem of abnormal key components caused by the internal temperature of the charging pile, the heat dissipation effect is usually improved by optimizing the heat dissipation design or by using a derating strategy to prevent the internal temperature from being too high. There are two common derating strategies:

[0004] 1. Derating based on the internal temperature threshold of the charging pile: When it is detected that the internal temperature exceeds the preset threshold, the charging power is automatically reduced, reducing the current flow, thereby slowing down the internal temperature rise. However, this method relies on a fixed current limit and cannot be flexibly adjusted according to actual conditions. The lack of flexibility leads to a failure to achieve the best balance between protecting equipment and improving charging efficiency.

[0005] 2. Derating based on ambient temperature: In hot weather or direct sunlight, the charging pile will proactively reduce power based on the external ambient temperature in advance to avoid a rapid increase in internal temperature due to insufficient heat dissipation capacity. This method sometimes enters the derating state in advance due to temperature fluctuations. Overprotection will reduce the actual utilization of the equipment, resulting in power being restricted when not necessary, and the charging pile cannot achieve the best charging efficiency.

[0006] Therefore, in order to effectively solve the problem of overheating of charging piles, a more intelligent, dynamic and accurate derating strategy is needed to provide thermal protection for charging piles. Summary of the invention

[0007] The present application provides a charging pile thermal derating method and a storage medium, which solves the technical problem of how to improve the charging efficiency of the charging pile and protect the equipment.

[0008] This application adopts the following technical solutions:

[0009] The present application provides a charging pile thermal derating method, comprising:

[0010] According to the current charging current query strategy table, determine the current derating gear and the maximum allowable temperature;

[0011] When the average temperature of the current internal environment of the charging pile is greater than the maximum allowable temperature corresponding to the current derating gear and the temperature is on an upward trend, the downshift operation is performed and the charging pile is controlled to allow maximum current output;

[0012] The judgment condition that the temperature is in an upward trend is: the temperature change rate is greater than a first temperature change rate threshold;

[0013] Or, the current average temperature of the internal environment of the charging pile is greater than the first temperature threshold and the current average temperature of the internal environment of the charging pile is greater than the temperature value corresponding to the previous sampling time and the internal environment temperature of the charging pile corresponding to the current sampling time is greater than the temperature value corresponding to the previous sampling time, wherein the first temperature threshold is the value obtained by adding the first temperature value to the maximum allowable temperature value.

[0014] Optionally, the method for obtaining the average temperature of the internal environment of the current charging pile includes:

[0015] Sampling a set of internal ambient temperature values ​​of the charging pile at a first sampling frequency and a first sampling time interval;

[0016] Eliminate the highest and lowest values ​​of the internal ambient temperature values ​​of a preset number of charging piles, and calculate the average temperature of the internal environment of the remaining current charging piles.

[0017] Optionally, the temperature change rate is calculated as:

[0018] K = (internal ambient temperature of the charging pile corresponding to the current sampling time – internal ambient temperature of the charging pile corresponding to the previous sampling time) / second sampling time interval

[0019] Where K is the temperature change rate.

[0020] Optionally, performing the downshift operation specifically includes: setting the PWM duty cycle corresponding to the current downshift gear to the PWM duty cycle corresponding to the target downshift gear, and the target downshift gear is lower than the current downshift gear.

[0021] Optionally, the method further comprises:

[0022] Determine the maximum allowable temperature corresponding to the current derating gear according to the current charging current;

[0023] When the average temperature of the current internal environment of the charging pile is less than the second temperature threshold and the temperature is on a downward trend, an upshift operation is performed, wherein the second temperature threshold is a value obtained by increasing the second temperature increment based on the maximum allowable temperature value.

[0024] Optionally, the judgment condition that the temperature is in a downward trend is: when the temperature change rate is less than a second temperature change rate threshold, the second temperature change rate threshold is a negative value.

[0025] Optionally, performing an upshift operation includes:

[0026] After the PWM duty cycle corresponding to the current derating gear is set to the PWM duty cycle corresponding to the maximum current allowed by the previous derating gear, no further adjustment is performed within the preset time period.

[0027] The present application also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, a charging pile thermal derating method as described in any one of the above embodiments is implemented.

[0028] The beneficial effects of this application are:

[0029] The charging pile thermal derating method provided in the present application can reduce the output current in sequence according to preset gears when detecting that the internal temperature of the charging pile is on an upward trend, thereby improving the overall charging efficiency; when it is detected that the temperature is on a downward trend, the maximum current output can be increased step by step until the internal temperature stabilizes.

[0030] The overall technical solution of this application adopts real-time detection of the internal temperature of the charging pile, and dynamically adjusts the maximum allowable current output of the charging pile according to the law of temperature change, so as to achieve the effect of providing optimal charging efficiency.

[0031] In addition, when the external temperature environment is particularly high, it can ensure that the internal devices are charged for a certain period of time in a safe working state, rather than immediately cutting off the charging or operating when the device temperature has exceeded the limit, thereby protecting the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A step diagram of a charging pile thermal derating method provided in this application.

[0033] Figure 2 A downshift operation flow chart provided for this application.

[0034] Figure 3 A flow chart of upshift operation provided for this application. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0036] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0037] The present application is further described in detail below with reference to the accompanying drawings:

[0038] This application provides a charging pile thermal derating method, such as Figure 1 As shown, the method includes S1-S2. It should be noted that the charging pile thermal derating method provided in the present application is not limited to step S1 and step S2. Figure 2 , Figure 2 A downshift operation flow chart is given.

[0039] S1: Query the strategy table according to the current charging current to determine the current derating gear and the maximum allowable temperature.

[0040] In one embodiment, the derating data is tested for the maximum internal temperature supported by the charging pile under different currents, and a strategy table for selecting a derating gear table is compiled and pre-stored in a storage module. The strategy table is obtained as follows: the charging pile is charged at a constant current, and the external ambient temperature is continuously adjusted until the internal temperature is stable and the internal device is at its maximum operating temperature critical point, and the internal maximum allowable temperature under the current is obtained. This test divides the charging current range from [0A, 32A] into 6 derating gears. Each derating gear contains the maximum current value, the minimum current value, the gear after downshifting, and the PWM duty cycle corresponding to the current gear corresponding to the maximum allowable temperature. The obtained strategy table is shown in Table 1.

[0041] Table 1

[0042]

[0043] According to the current charging current query table 1, determine the current derated gear and the maximum allowable temperature. For example, the current charging current is 24A, which is determined as gear 1, and the corresponding maximum allowable temperature is 88°C. The current control device controls the charging pile to charge the electric vehicle or other charging equipment with a PWM duty cycle of 53.3%. It should be noted that the downshift is determined based on the maximum output current allowed by the current situation. The switching of different gears is achieved by changing the PWM duty cycle to ensure that the maximum current under the downshift gear is the maximum output current allowed by the current situation. It should be noted that this embodiment can dynamically adjust the maximum allowable current output according to temperature changes. When the internal temperature fluctuates, it can accurately judge and control the maximum allowable current output; secondly, when it is detected that the temperature is on an upward trend, the output current can be reduced in sequence according to the preset gears to improve the overall charging efficiency.

[0044] S2: When the average temperature of the current internal environment of the charging pile is greater than the maximum allowable temperature corresponding to the current derating gear and the temperature is on an upward trend, the downshift operation is performed and the charging pile is controlled to allow maximum current output;

[0045] The judgment condition that the temperature is in an upward trend is: the temperature change rate is greater than a first temperature change rate threshold;

[0046] Or, the current average temperature of the internal environment of the charging pile is greater than the first temperature threshold and the current average temperature of the internal environment of the charging pile is greater than the temperature value corresponding to the previous sampling time and the internal environment temperature of the charging pile corresponding to the current sampling time is greater than the temperature value corresponding to the previous sampling time, wherein the first temperature threshold is the value obtained by adding the first temperature value to the maximum allowable temperature value.

[0047] In one embodiment, whether the temperature is on an upward trend is determined by the average temperature of the current internal environment of the charging pile. It should be noted that the determination condition that the temperature is on an upward trend is specifically divided into two situations:

[0048] (1) For the case of rapid temperature rise: If the first temperature change rate threshold is 0.1°C / 2min, and the temperature change rate K>0.1°C / 2min, it belongs to the case of rapid temperature rise. It should be noted that the first temperature change rate threshold here needs to be reasonably set according to the specific operating parameters of the actual equipment, for example, according to the charging power of the charging pile, the maximum allowable output current, the maximum allowable temperature of the internal environment, or a comprehensive evaluation of multiple conditions. Here, 0.1°C / 2min is the optimal parameter under this embodiment.

[0049] (2) For the case of slow temperature rise: With the first sampling interval of 10 minutes, first, the average temperature of the current charging pile internal environment calculated at the current moment must be greater than the first temperature threshold of the current gear, and the first temperature threshold is the value after adding the first temperature increment on the basis of the maximum allowable temperature value; secondly, it meets the following conditions: the average temperature of the current charging pile internal environment is greater than the temperature value corresponding to the sampling moment 10 minutes ago, and the internal environment temperature of the charging pile corresponding to the current sampling moment is greater than the temperature value corresponding to the moment 10 minutes ago. Specifically, for example, the current charging pile is in gear 1, the current internal environment temperature of the charging pile is 92°C, the corresponding maximum allowable temperature is 88°C, the first temperature increment is 1°C, and the first temperature threshold is 89°C. It can be judged that 92°C>89°C, and 92°C>90°C (the temperature value corresponding to the sampling moment 10 minutes ago), 91°C (the average temperature of the current internal environment of the charging pile)>90°C, indicating that the current charging pile is in a slow temperature rise state. It should be noted that the first temperature increment here is a positive value, and the specific size can be set according to the actual situation of temperature change.

[0050] When it is determined that the charging pile meets any of the above (1) or (2) temperature rise conditions, the downshift operation is performed. It should be noted that when downshifting, it is not necessary to downshift one level at a time. It is necessary to determine the downshift current corresponding to the current gear according to the actual measurement results. For example, if the current charging current is 32A and it is reduced to 23A and the temperature does not drop, it means that the current downshift current is insufficient. If you continue to charge or wait for the next downshift, there is a risk of overheating of key components during this period. Therefore, it is necessary to reduce the current to a lower level, such as 16A, so that the temperature drops significantly after the downshift. It should be noted that this embodiment provides an optimal solution. At present, the charging pile is set with 6 gears, and 3 gears are directly downshifted at one time; if it is not enough to downshift 3 gears, it is switched to the lowest gear to ensure that the temperature drops significantly, and after the gear shift, the output is output at the maximum output current allowed.

[0051] In addition, the judgment of slow heating conditions can avoid the situation where the temperature of the charging pile changes in a jittering manner. Although the average temperature of the current internal environment of the charging pile must be greater than the first temperature threshold of the current gear, if the temperature drops during this period, the current internal environment temperature of the charging pile is not as high as the temperature at the last sampling moment, and the process obviously does not belong to the heating condition, the accuracy of the judgment of the heating condition is improved.

[0052] In particular, the thermal derating method for a charging pile provided in the present application can ensure charging for a certain period of time while the internal devices are in a safe working state when the external temperature environment is particularly high, rather than directly not allowing charging or operating when the device temperature has exceeded the limit. This ensures that the safety of devices and equipment can be guaranteed as much as possible while outputting with the optimal current output solution.

[0053] Optionally, the method for obtaining the average temperature of the internal environment of the current charging pile includes: sampling a group of internal environment temperature values ​​of the charging pile at a first sampling frequency and a first sampling time interval; eliminating the highest and lowest values ​​of a preset number of internal environment temperature values ​​of the charging piles, and obtaining the average temperature of the remaining internal environment of the current charging pile.

[0054] In one embodiment, before determining whether to shift gears, the internal ambient temperature of the charging pile is collected. From the perspective of the internal structure of the charging pile and the stable temperature change, the temperature sensor closest to the relay module of the charging pile is selected as the temperature collection source. Specifically, the first temperature sampling frequency is 100ms once, the first sampling time interval is 1 minute, and 600 data are collected every 1 minute. The highest and lowest values ​​are removed and the average value is taken. The final calculated temperature value is the average temperature of the current internal environment of the charging pile, which is also the internal ambient temperature used by the derating strategy.

[0055] The internal ambient temperature value of the charging pile (filtered) is updated once every 1 minute. When the temperature value changes, the time consumed for this temperature change is calculated. The temperature change rate is calculated as follows: K = (internal ambient temperature of the charging pile corresponding to the current sampling moment - internal ambient temperature of the charging pile corresponding to the previous sampling moment) / second sampling time interval, where K is the temperature change rate.

[0056] Optionally, performing the downshift operation specifically includes: setting the PWM duty cycle corresponding to the current downshift gear to the PWM duty cycle corresponding to the target downshift gear, and the target downshift gear is lower than the current downshift gear.

[0057] In one embodiment, according to the current charging current, the maximum allowable temperature of the corresponding gear in the strategy table is found. If the current internal ambient temperature of the charging pile is greater than the threshold and the temperature is on an upward trend, downshifting is performed, and the PWM duty cycle is set to the PWM duty cycle corresponding to the maximum current allowed by the target downgraded gear. Specifically, the maximum allowable output current can be calculated according to the PWM duty cycle and current limit calculation formula, and the target gear can be determined.

[0058] Maximum allowed output current = (duty cycle * 100) * 0.6

[0059] Optionally, the method further comprises:

[0060] Determine the maximum allowable temperature corresponding to the current derating gear according to the current charging current;

[0061] When the average temperature of the current internal environment of the charging pile is less than the second temperature threshold and the temperature is on a downward trend, an upshift operation is performed, wherein the second temperature threshold is a value obtained by increasing the second temperature increment based on the maximum allowable temperature value.

[0062] Optionally, the judgment condition that the temperature is in a downward trend is: when the temperature change rate is less than a second temperature change rate threshold, the second temperature change rate threshold is a negative value.

[0063] In one embodiment, the technical solution provided by the present application also includes a shift-up setting, such as Figure 3 As shown, Figure 3 A flow chart for upshifting is given. First, the current derated gear is determined according to the current charging current. Secondly, it is determined that the average temperature of the internal environment of the current charging pile is lower than the second temperature threshold corresponding to the current gear, and the temperature is in a downward trend (temperature change rate K<-0.1℃ / 2mim, where K<-0.1℃ / 2mim is the second temperature change rate), and then the upshift process is performed. The PWM duty cycle is set to the PWM duty cycle corresponding to the maximum allowable current of the previous gear of the current gear, so that when the temperature is detected to be in a downward trend, the maximum current output can be increased step by step until the internal temperature stabilizes. It should be noted that when the second temperature increment is a negative value, it indicates that the temperature is decreasing. When the second temperature increment is -5℃, the second temperature threshold at this time is the value after subtracting 5℃ from the maximum allowable temperature value. For example, if the maximum allowable temperature corresponding to the current gear is 88℃, the second temperature threshold is 83℃.

[0064] Optionally, performing the upshift operation includes: after setting the PWM duty cycle corresponding to the current derating gear to the PWM duty cycle corresponding to the maximum current allowed by the previous derating gear, no further adjustment is performed within a preset time period.

[0065] It should be noted that in order to prevent the impact of frequent upshifting and downshifting on the current output of the charging pile devices, constraints are added to the derating frequency. After each downshift or upshift, taking the preset time period of 10 minutes as an example, no downshift or upshift operations will be performed within 10 minutes.

[0066] In one embodiment, the present application also provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a terminal device for storing programs and data. It is understandable that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating device of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor can load and execute one or more instructions stored in the computer-readable storage medium to implement the above-mentioned embodiment of a charging pile thermal derating method.

[0067] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, storage media, or computer program products. Therefore, the application can adopt the form of complete hardware embodiments, complete software embodiments, or embodiments in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0068] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices, and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0069] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1A function specified in one or more boxes.

[0070] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit it. Although the present application has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present application can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present application should be included in the scope of protection of the claims of the present application.

Claims

1. A charging pile thermal derating method, characterized in that: include: According to the current charging current query strategy table, determine the current derating gear and the maximum allowable temperature; When the average temperature of the current internal environment of the charging pile is greater than the maximum allowable temperature corresponding to the current derating gear and the temperature is on an upward trend, the downshift operation is performed and the charging pile is controlled to allow maximum current output; The judgment condition that the temperature is in an upward trend is: the temperature change rate is greater than a first temperature change rate threshold; Or, the average temperature of the current internal environment of the charging pile is greater than the first temperature threshold and the average temperature of the current internal environment of the charging pile is greater than the temperature value corresponding to the previous sampling time and the internal environment temperature of the charging pile corresponding to the current sampling time is greater than the temperature value corresponding to the previous sampling time, wherein the first temperature threshold is the value obtained by adding the first temperature increment to the maximum allowable temperature value.

2. A charging pile thermal derating method as claimed in claim 1, characterized in that: The method for obtaining the average temperature of the internal environment of the current charging pile includes: Sampling a set of internal ambient temperature values ​​of the charging pile at a first sampling frequency and a first sampling time interval; Eliminate the highest and lowest values ​​of a preset number of internal ambient temperature values ​​of the charging piles, and calculate the average temperature of the remaining internal environments of the current charging piles.

3. A charging pile thermal derating method as claimed in claim 1, characterized in that: The temperature change rate is calculated as follows: K = (internal ambient temperature of the charging pile corresponding to the current sampling time – internal ambient temperature of the charging pile corresponding to the previous sampling time) / second sampling time interval Wherein, K is the temperature change rate.

4. A charging pile thermal derating method as claimed in claim 1, characterized in that: The downshift operation is specifically performed by setting the PWM duty cycle corresponding to the current downshift gear to the PWM duty cycle corresponding to the target downshift gear, wherein the target downshift gear is lower than the current downshift gear.

5. A charging pile thermal derating method as claimed in claim 1, characterized in that: The method further comprises: Determine the maximum allowable temperature corresponding to the current derating gear position according to the current charging current; When the average temperature of the current internal environment of the charging pile is less than the second temperature threshold and the temperature is on a downward trend, the upshift operation is performed, wherein the second temperature threshold is a value obtained by increasing the second temperature increment based on the maximum allowable temperature value.

6. A charging pile thermal derating method as claimed in claim 5, characterized in that: The judgment condition that the temperature is in a downward trend is: when the temperature change rate is less than a second temperature change rate threshold, the second temperature change rate threshold is a negative value.

7. A charging pile thermal derating method as claimed in claim 5, characterized in that: Executing the upshift operation includes: After the PWM duty cycle corresponding to the current derating gear is set to the PWM duty cycle corresponding to the maximum current allowed by the previous derating gear, no further adjustment is performed within the preset time period.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, a charging pile thermal derating method as described in any one of claims 1 to 7 is implemented.

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