Discharging mode detection circuit and method and electric vehicle charging system

Abstract

The invention discloses a detection circuit and method for a discharging mode and an electric vehicle charging system. The detection circuit for the discharging mode comprises a potentiometer, a control switch and a detection module. The first end of the control switch is connected with a PP line of an electric vehicle charging system, and the second end is connected with the first end of the potentiometer. The second end of the potentiometer is connected with a PE line of the electric vehicle charging system and the detection module. The control switch is used for connecting the potentiometer to an electric loop corresponding to the PP line and the PE line so as to switch on the detection circuit; the potentiometer is used for providing resistance corresponding to at least one discharge mode; and the detection module is used for detecting the electric signal corresponding to the potentiometer, and identifying the discharge mode of the electric vehicle charging system according to the electric signal and the resistance currently provided by the potentiometer. According to the invention, the discharge mode of the electric vehicle charging system can be detected in real time by adopting a simple circuit structure.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicle charging, and in particular to a discharge mode detection circuit, method, and electric vehicle charging system. Background Art

[0002] With the increasing popularity of electric vehicles, reversible power transfer and external discharge are becoming increasingly popular. However, current discharge functionality in US-standard electric vehicles typically relies on the ISO 15118-20 protocol, which incorporates discharge into its bidirectional power transfer (BPT) functionality extension. During implementation, a discharge session must undergo multiple steps, including service discovery, session establishment, authorization, and charge / discharge parameter negotiation, before actual discharge begins. Complex data exchange and authentication between the electric vehicle and the load device are required, making the interaction cumbersome and posing high development and deployment costs. Some solutions utilize the ISO 15118-20 protocol to determine the discharge mode and perform power control. Because this protocol involves numerous communication, authentication, and power management steps, the interaction between the load device and the electric vehicle is complex, increasing the difficulty of development, debugging, and application. Furthermore, the complex protocol implementation may affect the charging system's compatibility with other charging modes. Therefore, simplifying the discharge mode detection and switching process while ensuring standard compatibility has become a pressing issue in the electric vehicle discharge field. Summary of the Invention

[0003] In view of this, the present application provides a discharge mode detection circuit, method and electric vehicle charging system to simplify the discharge mode detection process.

[0004] The present application provides a discharge mode detection circuit, comprising a potentiometer, a control switch and a detection module;

[0005] The first end of the control switch is connected to the PP line of the electric vehicle charging system, and the second end is connected to the first end of the potentiometer; the second end of the potentiometer is respectively connected to the PE line of the electric vehicle charging system and the detection module;

[0006] The control switch is used to connect the potentiometer to the electrical circuit corresponding to the PP line and the PE line to connect the detection circuit;

[0007] The potentiometer is used to provide a resistance corresponding to at least one discharge mode;

[0008] The detection module is used to detect the electrical signal corresponding to the potentiometer, and identify the discharge mode of the electric vehicle charging system according to the electrical signal and the resistance currently provided by the potentiometer.

[0009] Optionally, the potentiometer includes a first-level resistor, a second-level resistor, and a third-level resistor; the first-level resistor corresponds to a first discharge mode for discharging a load; the second-level resistor corresponds to a second discharge mode for discharging a residence; and the third-level resistor corresponds to a third discharge mode for discharging a commercial building.

[0010] Optionally, the resistance value of the first tier resistor is 33Ω; the resistance value of the second tier resistor is 51Ω; and the resistance value of the third tier resistor is 68Ω.

[0011] Optionally, the detection module is further used to calculate the theoretical resistance corresponding to the potentiometer based on the electrical signal. If the theoretical resistance is within a first range determined based on the resistance currently provided by the potentiometer, it is determined that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer.

[0012] Optionally, the detection module is further used to obtain the CP line voltage on the CP line of the electric vehicle charging system after determining that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer. If the CP line voltage is the first preset voltage within a preset time, the current discharge mode of the electric vehicle charging system is determined secondary.

[0013] The present application also provides a discharge mode detection method, which is applied to any of the above-mentioned discharge mode detection circuits; comprising:

[0014] Connect a potentiometer for providing a resistance corresponding to at least one discharge mode between the PP line and the PE line of the electric vehicle charging system;

[0015] An electrical signal corresponding to the potentiometer is detected, and a discharge mode of the electric vehicle charging system is identified based on the electrical signal and the resistance currently provided by the potentiometer.

[0016] Optionally, identifying the discharge mode of the electric vehicle charging system based on the electrical signal and the resistance currently provided by the potentiometer includes: calculating a theoretical resistance value corresponding to the potentiometer based on the electrical signal; if the theoretical resistance value is within a first range determined based on the resistance currently provided by the potentiometer, determining that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer.

[0017] The present application also provides an electric vehicle charging system, which includes a detection circuit for any of the above-mentioned discharge modes.

[0018] Optionally, the electric vehicle charging system further includes an MCU; the MCU is used to control the potentiometer to provide corresponding resistance in each discharge mode detection period.

[0019] Optionally, the MCU is further configured to turn on the control switch when the CP line voltage is 0.

[0020] Optionally, the detection module is arranged in the MCU.

[0021] In the above-mentioned discharge mode detection circuit, method and electric vehicle charging system of the present application, the control switch can connect the potentiometer to the electrical circuit corresponding to the PP line and the PE line to form a detection circuit. The detection module can detect the electrical signal corresponding to the potentiometer, and identify the discharge mode of the electric vehicle charging system based on the electrical signal and the resistance currently provided by the potentiometer. The discharge mode of the electric vehicle charging system can be detected in real time using a simple circuit structure without the need to perform complex ISO 15118 protocol handshakes, bypassing cumbersome protocol steps, simplifying the discharge mode identification process, and being compatible with existing charging modes, helping the electric vehicle charging system to quickly and reliably implement the electric vehicle discharge function. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 1 is a schematic diagram of a detection circuit structure of a discharge mode according to an embodiment of the present application;

[0024] Figure 2 1 is a schematic diagram of a detection circuit structure of a discharge mode according to an embodiment of the present application;

[0025] Figure 3 This is a partial structural diagram of an electric vehicle charging system according to an embodiment of the present application;

[0026] Figure 4 This is a schematic diagram of a discharge gun tip according to an embodiment of the present application;

[0027] Figure 5 This is a partial structural diagram of an electric vehicle charging system according to an embodiment of the present application. DETAILED DESCRIPTION

[0028] The following, in conjunction with the accompanying drawings, clearly and completely describes the technical solutions 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 this application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0029] In a first aspect, the present application provides a discharge mode detection circuit, which is arranged in an electric vehicle charging system. For example, the discharge mode detection circuit can be specifically arranged in a discharge gun head of the electric vehicle charging system, etc., and can detect the discharge mode of the electric vehicle charging system.

[0030] refer to Figure 1 As shown, the detection circuit of the discharge mode includes a potentiometer 100 , a control switch S1 and a detection module 200 .

[0031] The first end of the control switch S1 is connected to the PP (Proximity Pilot) line of the electric vehicle charging system, and the second end is connected to the first end of the potentiometer 100; the second end of the potentiometer 100 is respectively connected to the PE (protective ground) line of the electric vehicle charging system and the detection module 200.

[0032] The control switch S1 is used to connect the potentiometer 100 to the electrical circuit corresponding to the PP and PE wires, thereby energizing the detection circuit. Specifically, when the control switch S1 is closed, the potentiometer 100 is connected to the electrical circuit corresponding to the PP and PE wires, thereby energizing the detection circuit. When the control switch S1 is open, the detection circuit is shut off.

[0033] The potentiometer 100 is used to provide a resistance corresponding to at least one discharge mode; for example, the potentiometer 100 can provide a first resistance for detecting a first discharge mode and / or a second resistance for detecting a second discharge mode, and so on.

[0034] The detection module 200 is used to detect the electrical signal corresponding to the potentiometer 100 and identify the discharge mode of the electric vehicle charging system based on the electrical signal and the resistance currently provided by the potentiometer 100. Specifically, the electrical signal may include signals such as voltage and / or current; the detection module 200 can calculate the theoretical resistance value corresponding to the potentiometer 100 based on the electrical signal such as voltage and / or current, and based on the theoretical resistance value and the resistance currently provided by the potentiometer 100, identify whether the electric vehicle charging system is in the discharge mode represented by the resistance currently provided by the potentiometer 100.

[0035] Optionally, the detection module 200 can use a sampling circuit and / or MCU to obtain electrical signals such as voltage and / or current, calculate the corresponding resistance value based on the electrical signal, and make corresponding judgments based on the resistance value to identify the circuit structure of the corresponding discharge mode.

[0036] In the above-mentioned discharge mode detection circuit, the control switch S1 can connect the potentiometer 100 to the electrical loop corresponding to the PP line and the PE line to form a detection circuit. The detection module 200 can detect the electrical signal corresponding to the potentiometer 100, and identify the discharge mode of the electric vehicle charging system based on the electrical signal and the resistance currently provided by the potentiometer 100. The discharge mode of the electric vehicle charging system can be detected in real time using a simple circuit structure, without the need to perform complex ISO 15118 protocol handshakes, bypassing cumbersome protocol steps, simplifying the discharge mode identification process, and being compatible with existing charging modes, which helps the electric vehicle charging system to quickly and reliably realize the electric vehicle discharge function.

[0037] In some embodiments, reference Figure 2 As shown, the potentiometer 100 includes a first-level resistor RP1, a second-level resistor RP2, and a third-level resistor RP3.

[0038] The first resistor RP1 corresponds to a first discharge mode V2L for discharging a load.

[0039] The second resistor RP2 corresponds to a second discharge mode V2H for discharging to a residence.

[0040] The third resistor RP3 corresponds to the third discharge mode V2B for discharging to commercial buildings.

[0041] Optionally, the potentiometer 100 and the control switch S1 can also be connected to the MCU of the electric vehicle charging system (not shown in the figure). When the discharge mode detection is required, the MCU controls the control switch S1 to close to connect the discharge mode detection circuit and controls the potentiometer 100 to provide the resistance corresponding to the discharge mode to be detected, so that the detection module 200 calculates the resistance value of the corresponding potentiometer 100 based on the detected electrical signal, and determines whether the electric vehicle charging system is currently in the corresponding discharge mode based on the calculated resistance value and the resistance currently provided by the potentiometer 100.

[0042] In some examples, the resistance of the first resistor RP1 is 33Ω, which is used to detect the first discharge mode V2L; the resistance of the second resistor RP2 is 51Ω, which is used to detect the second discharge mode V2H; and the resistance of the third resistor RP3 is 68Ω, which is used to detect the third discharge mode V2B.

[0043] Specifically, the detection module 200 is further configured to calculate the theoretical resistance corresponding to the potentiometer 100 based on electrical signals such as voltage and / or current. If the theoretical resistance is within a first range determined based on the resistance currently provided by the potentiometer 100, the current discharge mode is determined to be the discharge mode corresponding to the resistance currently provided by the potentiometer. Furthermore, the detection module 200 may also obtain load parameters and / or resistance parameters on the PP line to calculate the theoretical resistance corresponding to the potentiometer 100 based on the obtained electrical signals, the load parameters, and / or the resistance parameters on the PP line.

[0044] Table 1

[0045] model resistance First range Maximum discharge power V2L 33Ω ±1％ 3.6KW V2H 51Ω ±1％ 6.6KW V2B 68Ω ±1％ 19.2KW

[0046] The first range may include ±1% of the resistance currently provided by the potentiometer 100. Specifically, as shown in Table 1, if the potentiometer 100 currently provides a first-level resistor RP1 with a resistance of 33Ω, the first range is 33Ω±1%. If the theoretical resistance calculated by the detection module 200 is within the first range of 33Ω±1%, the current discharge mode can be determined to be the first discharge mode V2L. If the potentiometer 100 currently provides a second-level resistor RP2 with a resistance of 51Ω, the first range is 51Ω±1%. If the theoretical resistance calculated by the detection module 200 is within the first range of 51Ω±1%, the current discharge mode can be determined to be the second discharge mode V2H. If the potentiometer 100 currently provides a third-level resistor RP3 with a resistance of 68Ω, the first range is 68Ω±1%. If the theoretical resistance calculated by the detection module 200 is within the first range of 68Ω±1%, the current discharge mode can be determined to be the third discharge mode V2B. Table 1 also shows the maximum discharge power corresponding to each discharge mode.

[0047] In some examples, the detection module 200 is further configured to, after determining that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer 100, obtain the CP line voltage on the CP line (control line) of the electric vehicle charging system. If the CP line voltage is a first preset voltage within a preset time, the current discharge mode of the electric vehicle charging system is determined to be the discharge mode corresponding to the resistance currently provided by the potentiometer 100, thereby improving the reliability of the discharge mode detection result. Optionally, the preset time can be set to a value such as 2s. Optionally, the first preset voltage can be set to a value such as 0V.

[0048] This example further adopts a secondary confirmation mechanism for the CP line signal to improve recognition reliability. After preliminarily determining that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer 100, the signal of the CP line is detected. When the CP line voltage is 0V for a preset time, the discharge mode is further confirmed and the discharge state is actually entered. Through this secondary confirmation mechanism, misjudgment or interference is avoided, ensuring that the system safely and reliably switches to the corresponding discharge function.

[0049] In the above discharge mode detection circuit, the control switch S1 can connect the potentiometer 100 to the electrical loop corresponding to the PP line and the PE line to form a detection circuit. The detection module 200 can detect the electrical signal corresponding to the potentiometer 100, and identify the discharge mode of the electric vehicle charging system based on the electrical signal and the resistance currently provided by the potentiometer 100. The discharge mode of the electric vehicle charging system can be detected in real time using a simple circuit structure, without the need to perform complex ISO 15118 protocol handshakes, bypassing cumbersome protocol steps, simplifying the discharge mode identification process, and being compatible with existing charging modes, which helps the electric vehicle charging system to quickly and reliably realize the electric vehicle discharge function.

[0050] A second aspect of the present application provides a method for detecting a discharge mode, which is applied to the discharge mode detection circuit described in any of the above embodiments, and includes:

[0051] Connect a potentiometer for providing a resistance corresponding to at least one discharge mode between the PP line and the PE line of the electric vehicle charging system;

[0052] An electrical signal corresponding to the potentiometer is detected, and a discharge mode of the electric vehicle charging system is identified based on the electrical signal and the resistance currently provided by the potentiometer.

[0053] In some embodiments, identifying the discharge mode of the electric vehicle charging system based on the electrical signal and the resistance currently provided by the potentiometer includes: calculating a theoretical resistance value corresponding to the potentiometer based on the electrical signal; if the theoretical resistance value is within a first range determined based on the resistance currently provided by the potentiometer, determining that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer.

[0054] In some examples, the discharge mode detection method further includes: after determining that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer, obtaining the CP line voltage on the CP line of the electric vehicle charging system; if within a preset time, the CP line voltage is the first preset voltage, then determining the current discharge mode of the electric vehicle charging system for the second time.

[0055] The above discharge mode detection method is applied to the discharge mode detection circuit described in any of the above embodiments, and has all the beneficial effects of the discharge mode detection circuit described in any of the above embodiments, which will not be described in detail here.

[0056] A third aspect of the present application provides an electric vehicle charging system, which includes the discharge mode detection circuit described in any one of the above embodiments.

[0057] Specifically, the electric vehicle charging system may also include components such as resistors connected to the PP line, for example, Figure 3 As shown, the electric vehicle charging system may further include a pull-up resistor R1 and a pull-down resistor R2. The first end of the pull-up resistor R1 is connected to the PP line, and the second end is used to access a second preset voltage (e.g., 5V). The first end of the pull-down resistor R2 is connected to the PP line, and the second end is grounded.

[0058] Optionally, the detection circuit of the discharge mode can be provided at the discharge gun head (also called CCS gun head) of the electric vehicle charging system, for example, Figure 4 As shown, the potentiometer 100 can be disposed inside the discharge gun head, and the control switch S1 can be disposed on the surface of the discharge gun head, so that the user can operate the control switch S1 conveniently.

[0059] In some embodiments, as Figure 3 As shown, the electric vehicle charging system further includes an MCU 300 ; the MCU 300 is used to control the potentiometer 100 to provide corresponding resistance in each discharge mode detection period.

[0060] In some examples, reference Figure 5 As shown, the detection module 200 is disposed in the MCU 300 so that the various functions of the detection module 200 are executed by the MCU 300, thereby simplifying the corresponding circuit structure.

[0061] Optionally, when discharge mode detection is required, the MCU 300 may first control the potentiometer 100 to provide or connect the first resistor RP1 to determine whether the current discharge mode is the first discharge mode V2L; if the current discharge mode is the first discharge mode V2L, discharge control is performed for the first discharge mode V2L. If the current discharge mode is not the first discharge mode V2L, the MCU 300 may then control the potentiometer 100 to provide or connect the second resistor RP2 to determine whether the current discharge mode is the second discharge mode V2H; if the current discharge mode is the second discharge mode V2H, discharge control is performed for the second discharge mode V2H. If the current discharge mode is not the second discharge mode V2H, the MCU 300 may then control the potentiometer 100 to provide or connect the third resistor RP3 to determine whether the current discharge mode is the third discharge mode V2B; if the current discharge mode is the third discharge mode V2B, discharge control is performed for the third discharge mode V2B.

[0062] In some examples, the MCU 300 is further configured to determine that a discharge mode detection is currently required when the CP line voltage is 0, and to turn on the control switch S1 to turn on the detection circuit to perform a discharge detection function.

[0063] In actual use, the MCU 300 is located on the OBC (on-board charger) on the side of the electric vehicle. The discharge gun head is inserted into the electric vehicle, establishing a basic connection with the vehicle. If the OBC recognizes that the CP voltage is 0V, it can turn on the control switch S1 to activate the detection circuit. The MCU 300 or the detection module 200 installed within it can detect the voltage and / or current corresponding to the potentiometer 100 and calculate the theoretical resistance value corresponding to the potentiometer 100. Based on the theoretical resistance value and the current resistance value provided by the potentiometer 100, it can identify whether the electric vehicle charging system is in the discharge mode represented by the current resistance provided by the potentiometer 100. Specifically, if the potentiometer 100 currently provides a first-level resistor RP1 with a resistance of 33Ω, the first range is 33Ω±1%. If the theoretical resistance calculated by the detection module 200 is within the first range of 33Ω±1%, the current discharge mode can be determined to be the first discharge mode V2L; if the potentiometer 100 currently provides a second-level resistor RP2 with a resistance of 51Ω, the first range is 51Ω±1%. If the theoretical resistance calculated by the detection module 200 is within the first range of 51Ω±1%, the current discharge mode can be determined to be the second discharge mode V2H; if the potentiometer 100 currently provides a third-level resistor RP3 with a resistance of 68Ω, the first range is 68Ω±1%. If the theoretical resistance calculated by the detection module 200 is within the first range of 68Ω±1%, the current discharge mode can be determined to be the third discharge mode V2B.

[0064] Furthermore, the MCU 300 or the detection module 200 provided therein can also obtain the CP line voltage on the CP line of the electric vehicle charging system after determining that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer 100. If the CP line voltage is 0V within the preset time, the current discharge mode of the electric vehicle charging system is determined for the second time to confirm that the discharge process has begun.

[0065] Alternatively, the vehicle's OBC can establish a simple agreement with the discharge gun, allowing the OBC's safety detection function to complete the discharge process, eliminating the need for the handshake and identity authentication steps in the ISO 15118-20 protocol. Alternatively, if the OBC fails to detect the resistance parameter corresponding to potentiometer 100 between the PP and PE or the CP signal detection fails to meet the requirements, it can maintain normal charging mode or determine an error state, without affecting the recognition of other charging modes. This discharge mode detection circuit allows for rapid detection of the discharge mode, bypassing complex communication protocols while ensuring compatibility with existing charging systems.

[0066] During the above-mentioned discharge mode detection process, after the vehicle OBC identifies the relevant discharge mode, the electric vehicle and the discharge device omit the handshake, identity authentication and power negotiation steps in the ISO 15118-20 protocol, and can directly switch to the discharge state by cooperating with the OBC and the BMS; the discharge mode is determined by quickly detecting the existence of the resistance parameter of the potentiometer 100, thereby reducing communication delay; it can also ensure that the recognition of other modes is not affected during use, including standard AC charging and DC fast charging mode recognition; through the design of reasonable circuits and protocols, the switching between different modes is smooth and seamless.

[0067] The above-mentioned electric vehicle charging system includes the discharge mode detection circuit described in any of the above-mentioned embodiments, and has all the beneficial effects of the discharge mode detection circuit described in any of the above-mentioned embodiments, which will not be repeated here.

[0068] Although the present application has been shown and described with respect to one or more implementations, equivalent variations and modifications will occur to those skilled in the art based on reading and understanding this specification and the accompanying drawings. The present application includes all such modifications and variations and is limited only by the scope of the appended claims. In particular, with respect to the various functions performed by the above-mentioned components, the terms used to describe such components are intended to correspond to any component (unless otherwise indicated) that performs the specified function of the component (e.g., it is functionally equivalent), even if it is not structurally equivalent to the disclosed structure that performs the function in the exemplary implementation of this specification shown herein.

[0069] That is, the above description is merely an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structural or equivalent process transformations made using the contents of the description and drawings of this application, such as the mutual combination of technical features between the various embodiments, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

[0070] In addition, in the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, for structural elements with the same or similar characteristics, the present application may use the same or different reference numerals to identify them. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0071] In this application, the word "exemplary" is used to mean "serving as an example, illustration or description". Any embodiment described in this application as "exemplary" is not necessarily to be construed as being more preferred or more advantageous than other embodiments. The above description is provided to enable any person skilled in the art to implement and use the present application. In the above description, various details are listed for the purpose of explanation. It should be understood that a person of ordinary skill in the art can recognize that the present application can be implemented without using these specific details. In other embodiments, well-known structures and processes will not be elaborated in detail to avoid obscuring the description of the present application with unnecessary details. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in this application.

Claims

1. A discharge mode detection circuit, characterized in that: The detection circuit of the discharge mode includes a potentiometer, a control switch and a detection module; The first end of the control switch is connected to the PP line of the electric vehicle charging system, and the second end is connected to the first end of the potentiometer; the second end of the potentiometer is respectively connected to the PE line of the electric vehicle charging system and the detection module; The control switch is used to connect the potentiometer to the electrical circuit corresponding to the PP line and the PE line to connect the detection circuit; The potentiometer is used to provide a resistance corresponding to at least one discharge mode; The detection module is used to detect the electrical signal corresponding to the potentiometer, and identify the discharge mode of the electric vehicle charging system according to the electrical signal and the resistance currently provided by the potentiometer.

2. The discharge mode detection circuit according to claim 1, characterized in that: The potentiometer includes a first-level resistor, a second-level resistor and a third-level resistor; The first resistor corresponds to a first discharge mode for discharging a load; The second resistor corresponds to a second discharge mode for discharging to a residence; The third level of resistance corresponds to a third discharge mode for discharging to commercial buildings.

3. The discharge mode detection circuit according to claim 2, characterized in that: The resistance of the first resistor is 33Ω; the resistance of the second resistor is 51Ω; The resistance of the third resistor is 68Ω.

4. The discharge mode detection circuit according to claim 3, characterized in that: The detection module is further configured to calculate a theoretical resistance corresponding to the potentiometer based on the electrical signal. If the theoretical resistance is within a first range determined based on the resistance currently provided by the potentiometer, the current discharge mode is determined to be the discharge mode corresponding to the resistance currently provided by the potentiometer.

5. The discharge mode detection circuit according to claim 4, characterized in that: The detection module is further configured to obtain a CP line voltage on a CP line of the electric vehicle charging system after determining that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer; if the CP line voltage is a first preset voltage within a preset time, the current discharge mode of the electric vehicle charging system is determined secondary.

6. A method for detecting a discharge mode, characterized in that: The discharge mode detection method is applied to the discharge mode detection circuit according to any one of claims 1 to 5; include: Connect a potentiometer for providing a resistance corresponding to at least one discharge mode between the PP line and the PE line of the electric vehicle charging system; An electrical signal corresponding to the potentiometer is detected, and a discharge mode of the electric vehicle charging system is identified based on the electrical signal and the resistance currently provided by the potentiometer.

7. The method for detecting a discharge mode according to claim 6, wherein: The step of identifying the discharge mode of the electric vehicle charging system according to the electrical signal and the resistance currently provided by the potentiometer includes: A theoretical resistance value corresponding to the potentiometer is calculated based on the electrical signal. If the theoretical resistance value is within a first range determined based on the resistance currently provided by the potentiometer, it is determined that the current discharge mode is the discharge mode corresponding to the resistance currently provided by the potentiometer.

8. An electric vehicle charging system, characterized in that: The electric vehicle charging system includes the discharge mode detection circuit according to any one of claims 1 to 5.

9. The electric vehicle charging system according to claim 8, characterized in that: The electric vehicle charging system further includes an MCU; The MCU is used to control the potentiometer to provide corresponding resistance during each discharge mode detection period.

10. The electric vehicle charging system according to claim 9, characterized in that: The MCU is also used to turn on the control switch when the CP line voltage is 0; And / or the detection module is arranged in the MCU.

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