Temperature compensation method and apparatus based on direct current charging base

Abstract

Disclosed are a temperature compensation method and apparatus based on a direct current charging base. The method comprises: acquiring the temperature of a terminal of a direct current charging base; calculating temperature compensation function coefficients corresponding to different current values; and according to the acquired temperature of the terminal of the direct current charging base, the temperature compensation function coefficients corresponding to the different current values, and a pre-established temperature compensation function, obtaining a corrected temperature, the corrected temperature being transmitted to a charge controller of an electric vehicle. According to the present invention, a temperature error caused by temperature transmission delay can be compensated in the charging process of an electric vehicle, such that the vehicle can be charged safely, accurately, and quickly.

Description

Method and device for temperature compensation based on DC charging station

[0001] This application claims priority to Chinese patent application No. 202110839832.2, filed on July 23, 2021, entitled “Method and device based on temperature compensation of DC charging station”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of direct current charging of electric vehicles, and in particular to a method and device based on temperature compensation of a direct current charging stand. Background Art

[0003] This section is intended to provide a background or context to the embodiments of the invention that are recited in the claims. No statement herein is admitted to be prior art by virtue of its inclusion in this section.

[0004] With the development of new energy vehicles, safe, accurate, and fast charging has become a new market demand. However, during the charging process, temperature transmission delays can cause temperature errors, resulting in inaccurate temperature measurements at the DC charging terminal. This makes it impossible to ensure safe, accurate, and fast charging of electric vehicles.

[0005] Summary of the Invention

[0006] An embodiment of the present invention provides a method for temperature compensation based on a DC charging station, for compensating for temperature errors caused by temperature transmission delays. The method includes:

[0007] Collect the temperature of the DC charging seat terminals;

[0008] Calculate the temperature compensation function coefficient corresponding to different current values;

[0009] A corrected temperature is obtained based on the collected temperature of the DC charging seat terminal, the temperature compensation function coefficients corresponding to different current values, and a pre-established temperature compensation function; the corrected temperature is sent to the charging controller of the electric vehicle.

[0010] An embodiment of the present invention further provides a device for temperature compensation based on a DC charging station, for compensating for temperature errors caused by temperature transmission delays. The device includes:

[0011] Temperature collection unit, used to collect the temperature of the DC charging seat terminals;

[0012] A coefficient calculation unit, used to calculate the temperature compensation function coefficients corresponding to different current values;

[0013] The compensation unit is used to obtain a corrected temperature based on the collected temperature of the DC charging seat terminal, the temperature compensation function coefficient corresponding to different current values, and a pre-established temperature compensation function; the corrected temperature is sent to the charging controller of the electric vehicle.

[0014] An embodiment of the present invention further provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method based on temperature compensation of a DC charging station is implemented.

[0015] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program for executing the above-mentioned method for temperature compensation based on a DC charging station.

[0016] In an embodiment of the present invention, a solution based on temperature compensation of a DC charging seat is compared with the technical solution in the prior art in which, during the charging process, temperature errors are caused due to temperature transmission delays, that is, the collected temperature of the DC charging seat terminal is inaccurate, thereby failing to ensure safe, accurate and fast charging of the electric vehicle. The solution involves: collecting the temperature of the DC charging seat terminal; calculating the temperature compensation function coefficient corresponding to different current values; obtaining a corrected temperature based on the collected temperature of the DC charging seat terminal, the temperature compensation function coefficient corresponding to different current values, and a pre-established temperature compensation function; the corrected temperature is sent to the charging controller of the electric vehicle, which can compensate for the temperature error caused by the temperature transmission delay during the charging process of the electric vehicle, thereby achieving safe, accurate and fast charging of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention. In the drawings:

[0018] FIG1 is a schematic diagram showing the delay and deviation in phase and amplitude between the temperature measured by the temperature sensor and the actual temperature of the terminal according to an embodiment of the present invention;

[0019] FIG2 is a schematic flow chart of a method for temperature compensation based on a DC charging station according to an embodiment of the present invention;

[0020] FIG3 is a schematic diagram of the principle of temperature compensation based on a DC charging station according to an embodiment of the present invention;

[0021] FIG4 is a schematic flow chart of a method for temperature compensation based on a DC charging station according to another embodiment of the present invention;

[0022] FIG5 is a schematic diagram of determining coefficient values ​​using MATLAB fitting when the charging current is 200 A in an embodiment of the present invention;

[0023] FIG6 is a schematic structural diagram of a device for temperature compensation based on a DC charging station according to an embodiment of the present invention;

[0024] FIG7 is a schematic structural diagram of a temperature acquisition unit in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0026] The inventors discovered a technical problem: In a DC charger, the temperature sensor measures the temperature of the white terminal. While the sensor is located very close to the terminal but not directly attached to the terminal surface, there is a delay and loss in the transmission of the terminal's temperature to the sensor. As shown in Figure 1, the temperature measured by the temperature sensor exhibits a phase delay and deviation from the actual temperature measured on the terminal surface.

[0027] In light of the above technical issues, the inventors have proposed a solution for DC charging station temperature compensation. This solution compensates for temperature errors caused by temperature transmission delays during the charging process, ensuring safe, accurate, and fast charging of electric vehicles. This solution for DC charging station temperature compensation is described in detail below.

[0028] FIG2 is a flow chart of a method for temperature compensation based on a DC charging station according to an embodiment of the present invention. As shown in FIG2 , the method includes the following steps:

[0029] Step 101: collecting the temperature of the DC charging seat terminal;

[0030] Step 102: Calculating temperature compensation function coefficients corresponding to different current values;

[0031] Step 103: Obtain a corrected temperature based on the collected temperature of the DC charging seat terminal, the temperature compensation function coefficients corresponding to different current values, and a pre-established temperature compensation function; the corrected temperature is sent to the charging controller of the electric vehicle.

[0032] The DC charging station temperature compensation method provided by this embodiment uses software differential and hysteresis correction to adjust for temperature errors caused by temperature transmission and losses, ensuring accurate and reliable temperature correction and enabling safe, accurate, and rapid vehicle charging. The steps involved in this method are described in detail below, with reference to Figures 3 through 7.

[0033] As shown in Figure 3, the temperature processing process mainly includes the following three parts: (1) temperature acquisition; (2) calculation of the temperature compensation function coefficient ATs based on the current value; (3) determination of the delay (temperature) compensation function. The details are as follows:

[0034] (1) Temperature acquisition, i.e., the detailed implementation of step 101 above: The temperature of the DC charging seat terminal acquired by the embodiment of the present invention is obtained by dividing the voltage by a temperature sensor and a voltage-dividing resistor, and then is converted into different voltages after isolation and amplification. The voltage is then input into the single-chip microcomputer (temperature correction unit, i.e., the compensation unit mentioned below). The temperature value S corresponding to the voltage of the temperature sensor can be obtained by looking up the table (the relationship between voltage and temperature). The hardware circuit (temperature acquisition circuit) block diagram can be shown in Figure 7. The advantages of dividing the voltage by a temperature sensor and a resistor and converting it into different voltages after isolation and amplification are: isolating the interference of the front-end signal, converting the resistance signal into a voltage signal that is easy for the single-chip microcomputer to collect, and further improving the safety and accuracy of charging.

[0035] As can be seen from the above, in one embodiment, collecting the temperature of the DC charging seat terminal may include collecting the temperature of the DC charging seat terminal using the following temperature collection unit:

[0036] A voltage dividing resistor, a first end of which is connected to a 5V voltage terminal after the 12V voltage at the vehicle end is converted;

[0037] A temperature sensor, having a first end connected to the second end of the voltage divider resistor and a second end grounded, for collecting a voltage signal from a terminal of the DC charging station;

[0038] A temperature acquisition circuit, the input end of which is connected to the first end of the temperature sensor, is used to isolate the voltage signal acquired by the temperature sensor to obtain an isolated voltage;

[0039] The voltage divider circuit has an input end connected to the output end of the temperature acquisition circuit, and is used to convert the isolated voltage into an effective voltage signal that is easy to acquire; the effective voltage signal that is easy to acquire is used to determine the temperature value corresponding to the voltage collected by the temperature sensor as the temperature of the DC charging seat terminal based on the pre-established relationship between voltage and temperature.

[0040] In a specific implementation, the temperature obtained by the temperature acquisition unit is more accurate, thereby further improving the accuracy and safety of the temperature compensation of the DC charging station.

[0041] (2) Calculate the compensation function coefficient ATs by the current value: the current range flowing through the charging seat terminal is 100A-500A. For different currents, the square value of the current is proportional to the temperature rise. By taking the differential method, the current value is proportional to the differential value of the temperature. ATs finally has a corresponding relationship with the temperature rise rate. However, since the temperature rise rate corresponding to different current segments during the calibration process is not linear, the current obtained at different temperature rise rates after subsequent segmentation has different KK and bb, and then the K and b corresponding to the ATs obtained according to different currents are also different. The advantage of the current value being proportional to the differential value of the temperature is that when the external conditions remain unchanged, the current value and the temperature rise rate are determined to be linear. The differential value of the temperature = the temperature difference / the time difference. The differential value of the temperature corresponds to the slope of the temperature rise over a period of time (temperature rise rate, temperature change rate). By actually measuring the slope K1 of the temperature rise of 100A and the slope of 500A K2, the different current values ​​ya corresponding to the slope x of different temperature rises are obtained through the linear equation y=KKx+bb; where KK=(500-100) / (k2-k1); bb is a constant, y is the current value ya corresponding to the slope of different temperature rises, and ATs is determined by testing the temperature curve corresponding to the actual fixed charging current and fitting it to the standard temperature through MATLAB to obtain the coefficient. When the current is set to 500A, the corresponding ATs is ATs-500, and when the current is set to 100A, the corresponding ATs is ATs-100. In this way, the ATs of the delay compensation under different currents ya is the corresponding relationship formula: ATs=ya×K+b, where: K=((ATs-500)–(ATs-100)) / (500-100), ATs is the temperature compensation function coefficient, ya is the current value, where K and b are constants, determined by actual measurement. In order to measure accurately, the over-limit current 500A-700A and the part below the working current 50A-100A are calculated using the same formula to obtain different K and b coefficients, and are individually corrected to obtain different ATs.

[0042] As can be seen from the above, in one embodiment, calculating the temperature compensation function coefficients corresponding to different current values ​​may include:

[0043] Make the current value proportional to the differential value of the temperature, and obtain different current values ​​corresponding to different temperature rise rates;

[0044] According to different current values ​​corresponding to different temperature rise rates, temperature compensation function coefficients corresponding to different current values ​​are determined.

[0045] As can be seen from the above, in one embodiment, calculating the temperature compensation function coefficients corresponding to different current values ​​may include calculating the temperature compensation function coefficients corresponding to different current values ​​according to the following formula:

[0046] ATs=ya×K+b;

[0047] Where: K = ((ATs-500)-(ATs-100)) / (500-100), ATs is the temperature compensation function coefficient, ya is the current value, K and b are constants.

[0048] As can be seen from the above, in one embodiment, different K and b can be obtained according to the over-limit current range of 500A-700A and the lower-than-operating current range of 50A-100A.

[0049] (3) Determination of delay (temperature) compensation function: During the test, temperature is compensated due to the transmission delay and loss of temperature. The compensation equation is a first-order delay function formula as follows: y2 = (1 + Ts × S) / (1 + ATs × S); In this formula, Ts is a constant, ATs is a variable in the temperature rise process that is proportional to the current, and S is the current sampled temperature value (the temperature of the DC charging station terminal). Ts and ATs are determined by fitting the temperature curve corresponding to the actual fixed charging current to the standard temperature through MATLAB to obtain the coefficients. The parameter Ts is fixed, and different ATs values ​​corresponding to different currents are obtained. In the delay compensation calculation, different ATs values ​​are called for corresponding to different temperature change rates. Figure 5 is a schematic diagram of the coefficient value determined by MATLAB fitting when the charging current is 200A.

[0050] (4) The entire temperature correction flow chart is shown in Figure 4. The temperature correction value (corrected temperature) is sent to the vehicle's charging controller CCU via the CAN line. The vehicle's charging controller CCU can use the corrected temperature to charge the electric vehicle safely, accurately and quickly.

[0051] In specific implementation, after determining the sampling temperature, the temperature compensation function and the temperature compensation function coefficient, the temperature correction formula can be used to determine the final corrected temperature; the corrected temperature is sent to the charging controller of the electric vehicle.

[0052] In summary, the embodiments of the present invention achieve: stable and rapid charging of a car; simple and rapid error correction through software, that is, correction of sampled temperature values ​​under different currents through software differential and hysteresis correction, which is simple, rapid and practical.

[0053] The beneficial technical effect of the embodiment of the present invention is: the method based on DC charging stand temperature compensation provided by the embodiment of the present invention realizes compensation for temperature errors caused by temperature transmission delay during the charging process of electric vehicles, thereby realizing safe, accurate and fast charging of the car.

[0054] The present invention also provides a device for DC charging station temperature compensation, as described in the following embodiments. Because the principles of this device are similar to those of the method for DC charging station temperature compensation, the implementation of this device can be referenced to the implementation of the method for DC charging station temperature compensation, and any repetitions will not be repeated.

[0055] FIG6 is a schematic diagram of the structure of a device based on temperature compensation of a DC charging station according to an embodiment of the present invention, the device comprising:

[0056] Temperature acquisition unit 01, used to collect the temperature of the DC charging seat terminal;

[0057] The coefficient calculation unit 02 is used to calculate the temperature compensation function coefficient corresponding to different current values;

[0058] The compensation unit 03 is used to obtain a corrected temperature based on the collected temperature of the DC charging seat terminal, the temperature compensation function coefficient corresponding to different current values, and a pre-established temperature compensation function; the corrected temperature is sent to the charging controller of the electric vehicle.

[0059] In one embodiment, as shown in FIG7 , the temperature acquisition unit may include:

[0060] A voltage dividing resistor, a first end of which is connected to a 5V voltage terminal after the 12V voltage at the vehicle end is converted;

[0061] A temperature sensor, having a first end connected to the second end of the voltage divider resistor and a second end grounded, for collecting a voltage signal from a terminal of the DC charging station;

[0062] A temperature acquisition circuit, the input end of which is connected to the first end of the temperature sensor, is used to isolate the voltage signal acquired by the temperature sensor to obtain an isolated voltage;

[0063] The voltage divider circuit has an input end connected to the output end of the temperature acquisition circuit, and is used to convert the isolated voltage into an effective voltage signal that is easy to acquire; the effective voltage signal that is easy to acquire is used to determine the temperature value corresponding to the voltage collected by the temperature sensor as the temperature of the DC charging seat terminal based on the pre-established relationship between voltage and temperature.

[0064] In one embodiment, the coefficient calculation unit may be specifically used to:

[0065] Make the current value proportional to the differential value of the temperature, and obtain different current values ​​corresponding to different temperature rise rates;

[0066] According to different current values ​​corresponding to different temperature rise rates, temperature compensation function coefficients corresponding to different current values ​​are determined.

[0067] In one embodiment, the coefficient calculation unit may be specifically configured to calculate the temperature compensation function coefficients corresponding to different current values ​​according to the following formula:

[0068] ATs=ya×K+b;

[0069] Where: ATs is the temperature compensation function coefficient, ya is the current value, K and b are constants.

[0070] In one embodiment, different K and b may be obtained according to the over-limit current range of 500A-700A and the lower-than-operating current range of 50A-100A.

[0071] An embodiment of the present invention further provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the above-mentioned method based on temperature compensation of a DC charging station is implemented.

[0072] An embodiment of the present invention further provides a computer-readable storage medium storing a computer program for executing the above-mentioned method for temperature compensation based on a DC charging station.

[0073] In an embodiment of the present invention, a solution based on temperature compensation of a DC charging seat is compared with the technical solution in the prior art in which, during the charging process, temperature errors are caused due to temperature transmission delays, that is, the collected temperature of the DC charging seat terminal is inaccurate, thereby failing to ensure safe, accurate and fast charging of the electric vehicle. The solution involves: collecting the temperature of the DC charging seat terminal; calculating the temperature compensation function coefficient corresponding to different current values; obtaining a corrected temperature based on the collected temperature of the DC charging seat terminal, the temperature compensation function coefficient corresponding to different current values, and a pre-established temperature compensation function; the corrected temperature is sent to the charging controller of the electric vehicle, which can compensate for the temperature error caused by the temperature transmission delay during the charging process of the electric vehicle, thereby achieving safe, accurate and fast charging of the vehicle.

[0074] It will be understood by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Thus, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0075] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of processes and / or boxes 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 produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0076] These computer program instructions may also be stored in a computer-readable memory that can direct 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 a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0077] 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, so that the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0078] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for temperature compensation based on a DC charging station, characterized in that: include: Collect the temperature of the DC charging seat terminals; Calculate the temperature compensation function coefficient corresponding to different current values; The corrected temperature is obtained based on the collected temperature of the DC charging seat terminal, the temperature compensation function coefficient corresponding to different current values, and the pre-established temperature compensation function; The corrected temperature is sent to the electric vehicle's charge controller.

2. The method for temperature compensation based on a DC charging station according to claim 1, characterized in that: Collecting the temperature of the DC charging seat terminal includes using the following temperature collection units to collect the temperature of the DC charging seat terminal: A voltage dividing resistor, a first end of which is connected to the vehicle voltage terminal; A temperature sensor, having a first end connected to the second end of the voltage divider resistor and a second end grounded, for collecting a voltage signal from a terminal of the DC charging station; A temperature acquisition circuit, the input end of which is connected to the first end of the temperature sensor, is used to isolate the voltage signal acquired by the temperature sensor to obtain an isolated voltage; A voltage divider circuit, whose input end is connected to the output end of the temperature acquisition circuit, is used to convert the isolated voltage into an effective voltage signal that is easy to acquire; The effective voltage signal that is easy to collect is used to determine the temperature value corresponding to the voltage collected by the temperature sensor as the temperature of the DC charging seat terminal based on the pre-established relationship between voltage and temperature.

3. The method for temperature compensation based on a DC charging station according to claim 1, characterized in that: Calculate the temperature compensation function coefficients corresponding to different current values, including: Make the current value proportional to the differential value of the temperature, and obtain different current values ​​corresponding to different temperature rise rates; According to different current values ​​corresponding to different temperature rise rates, temperature compensation function coefficients corresponding to different current values ​​are determined.

4. The method for temperature compensation based on a DC charging station according to claim 3, characterized in that: Calculating the temperature compensation function coefficients corresponding to different current values, including calculating the temperature compensation function coefficients corresponding to different current values ​​according to the following formula: ATs=ya×K+b; Where: ATs is the temperature compensation function coefficient, ya is the current value, K and b are constants.

5. The method for temperature compensation based on a DC charging station according to claim 4, characterized in that: Different K and b are obtained according to the over-limit current range of 500A-700A and the range of lower than working current of 50A-100A.

6. A device based on DC charging station temperature compensation, characterized in that: include: Temperature collection unit, used to collect the temperature of the DC charging seat terminals; A coefficient calculation unit, used to calculate the temperature compensation function coefficients corresponding to different current values; The compensation unit is used to obtain the corrected temperature based on the collected temperature of the DC charging seat terminal, the temperature compensation function coefficient corresponding to different current values, and the pre-established temperature compensation function; The corrected temperature is sent to the electric vehicle's charge controller.

7. The device for temperature compensation based on a DC charging station according to claim 6, characterized in that: The temperature acquisition unit includes: A voltage dividing resistor, a first end of which is connected to the vehicle voltage terminal; A temperature sensor, having a first end connected to the second end of the voltage divider resistor and a second end grounded, for collecting a voltage signal from a terminal of the DC charging station; A temperature acquisition circuit, the input end of which is connected to the first end of the temperature sensor, is used to isolate the voltage signal acquired by the temperature sensor to obtain an isolated voltage; The voltage divider circuit has an input end connected to the output end of the temperature acquisition circuit, and is used to convert the isolated voltage into an effective voltage signal that is easy to acquire; the effective voltage signal that is easy to acquire is used to determine the temperature value corresponding to the voltage collected by the temperature sensor as the temperature of the DC charging seat terminal based on the pre-established relationship between voltage and temperature.

8. The device for temperature compensation based on a DC charging station according to claim 6, characterized in that: The coefficient calculation unit is specifically used for: Make the current value proportional to the differential value of the temperature, and obtain different current values ​​corresponding to different temperature rise rates; According to different current values ​​corresponding to different temperature rise rates, temperature compensation function coefficients corresponding to different current values ​​are determined.

9. The device for temperature compensation based on a DC charging station according to claim 8, characterized in that: The coefficient calculation unit is specifically used to calculate the temperature compensation function coefficient corresponding to different current values ​​according to the following formula: ATs=ya×K+b; Where: ATs is the temperature compensation function coefficient, ya is the current value, K and b are constants.

10. The device for temperature compensation based on a DC charging station according to claim 9, characterized in that: Different K and b are obtained according to the over-limit current range of 500A-700A and the range of lower than working current of 50A-100A.

11. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 5 is implemented.

12. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program for executing the method according to any one of claims 1 to 5.