Disconnection detection circuit, disconnection detection method, and charging system

Abstract

The application provides a disconnection detection circuit, a disconnection detection method and a charging system. The disconnection detection circuit is applied to an electric device and comprises a power supply circuit, a first detection branch, a bias circuit and a control circuit. The power supply circuit is used for providing a power supply for a first resistor in a charging device. The first detection branch is connected between a first detection point and a first sampling port of the control circuit and is used for detecting a first voltage at the first detection point. The bias circuit is arranged on the first detection branch and is used for biasing the first voltage at the first detection point and providing a bias voltage for the first sampling port of the control circuit. The control circuit is used for controlling the power supply circuit to be in an off state when the electric device is charged by the charging device, and performing disconnection detection between a ground wire of the electric device and a ground wire of the charging device according to the bias voltage. The application can detect the disconnection between the ground wire of the electric device and the ground wire of the charging device.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a wire breakage detection circuit, a wire breakage detection method, and a charging system. Background Technology

[0002] In DC charging systems for electric vehicles, to ensure electrical safety during the charging process, national standards have set forth clear requirements for the open-circuit testing of the protective earth (PE) wire of electrical equipment (such as vehicles). This test aims to confirm whether the ground connection between the vehicle and the charging device (such as the charging gun) is normal during the charging process, in order to prevent safety hazards caused by ground wire breakage.

[0003] In related technologies, the voltage signal of the second charging connection (CC2) is directly fed to the microcontroller unit (MCU) for sampling after being filtered by RC. Under normal charging conditions, this solution can collect the voltage signal at the second charging connection (CC2). However, when the PE line is broken, the voltage signal at the second charging connection (CC2) cannot be collected, and the sampling signal will be lost when the PE line is broken. Therefore, this solution cannot detect whether the PE line is broken. Summary of the Invention

[0004] This application provides a broken wire detection circuit, a broken wire detection method, and a charging system, which can detect the broken circuit of the PE wire.

[0005] The technical solution of this application embodiment is implemented as follows:

[0006] In a first aspect, embodiments of this application provide a disconnection detection circuit applied to an electrical device. The disconnection detection circuit includes a power supply circuit, a first detection branch, a bias circuit, and a control circuit, wherein: the power supply circuit is used to provide power to a first resistor in a charging device; the first detection branch is connected between a first detection point and a first sampling port of the control circuit, and is used to detect a first voltage at the first detection point; the bias circuit is disposed on the first detection branch, and is used to bias the first voltage at the first detection point and provide a bias voltage to the first sampling port of the control circuit; the control circuit is used to control the power supply circuit to be in an open state when the electrical device is being charged by the charging device, and to perform disconnection detection between the ground wire of the electrical device and the ground wire of the charging device based on the bias voltage obtained from the first sampling port.

[0007] Through the aforementioned technical means, power is first supplied to the first resistor in the charging device via the power supply circuit. The first voltage at the first detection point is collected using the first detection branch, and the first voltage is biased by a bias circuit, thereby converting any possible negative voltage signal into a positive voltage signal input to the control circuit. This ensures that the control circuit can accurately collect the first voltage signal at the first detection point, regardless of whether it is positive or negative, without signal loss, thus improving the reliability of open circuit detection. The control circuit can detect open circuits between the ground wire of the electrical equipment and the ground wire of the charging device through the bias voltage. This design overcomes the problem that existing circuits cannot directly sample negative voltage, achieving effective detection of open circuits between the ground wires of the electrical equipment and the charging device. The open circuit detection circuit has a simple structure, reducing costs. Furthermore, the power supply circuit is kept disconnected during charging, avoiding the influence of the charging current on the ground wire open circuit detection, thus improving the accuracy of the detection.

[0008] In some embodiments, the control circuit is further configured to determine that there is no open circuit fault between the ground wire of the electrical device and the ground wire of the charging device when the amplitude of the bias voltage is within a first preset range; and to determine that there is an open circuit fault between the ground wire of the electrical device and the ground wire of the charging device when the amplitude of the bias voltage is within a second preset range; wherein the lower limit of the first preset range is higher than the upper limit of the second preset range.

[0009] By employing the aforementioned technical methods and setting different amplitude thresholds to distinguish between normal and open circuit states, automatic judgment of whether an open circuit fault exists between ground wires is achieved. Furthermore, compared to the traditional method that relies solely on a single voltage value, setting the lower limit of a first preset range higher than the upper limit of a second preset range ensures clear judgment logic and reduces the likelihood of misjudgment, thus improving the accuracy and reliability of open circuit detection.

[0010] In some embodiments, the power supply circuit includes a disconnection detection switch and a first power supply; wherein: the first power supply and the disconnection detection switch are connected in series, the first detection point is disposed between the disconnection detection switch and the first resistor; the control circuit is further configured to control the disconnection detection switch to open when the power device is being charged by the charging device, so that the power supply circuit is in an open state.

[0011] By using the above-mentioned technical means, the state of the power supply circuit can be controlled by controlling the on / off state of the disconnection detection switch, making the disconnection of the power supply circuit more reliable.

[0012] In some embodiments, the bias circuit includes a first bias branch and a second bias branch; the second bias branch is disposed on the first detection branch; and the first bias branch is connected between the power supply circuit and the first bias branch.

[0013] By employing the aforementioned technical means, the two bias branches can be configured to provide the bias circuit with greater flexibility and adaptability, enabling more effective adjustment of the detection point voltage and meeting the sampling requirements of different application scenarios.

[0014] In some embodiments, the first bias branch circuit includes a first bias resistor, and the second bias branch includes a second bias resistor, wherein: the first end of the first bias resistor is connected to the positive terminal of the first power supply; the first end of the second bias resistor is connected to the first detection point; and the second end of the first bias resistor is connected to the second end of the second bias resistor and the first sampling port, respectively.

[0015] By employing the aforementioned technical means and using a voltage divider structure composed of two bias resistors, the bias adjustment of the first voltage at the first detection point is achieved, ensuring that the bias voltage output is a positive signal. This simple and reliable resistor voltage divider method is easy to implement and low in cost. Simultaneously, it can stably convert negative voltage to positive voltage, improving the stability of the sampling signal and facilitating the design of the control circuit's judgment logic.

[0016] In some embodiments, the disconnection detection circuit further includes a first filtering circuit, and the first filtering circuit is disposed between the bias circuit and the first sampling port; wherein: the first filtering circuit is used to perform voltage regulation and filtering on the bias voltage so that the first sampling port obtains a bias voltage that satisfies the first condition.

[0017] By employing the aforementioned techniques and adding a first filter circuit between the bias circuit and the control circuit, noise and fluctuations in the bias voltage can be effectively removed, improving the stability and accuracy of the bias voltage. Compared to the unfiltered solution, this reduces false positives and improves the accuracy and reliability of open circuit detection.

[0018] In some embodiments, the power supply circuit further includes a first pull-up resistor, wherein the first pull-up resistor is connected in series on the connection line between the first power supply and the disconnection detection switch.

[0019] By using the above-mentioned technical means, adding a first pull-up resistor can make the opening or closing of the disconnection detection switch more stable, improve the anti-interference capability of the disconnection detection switch, and make the sampling of the first voltage at the first sampling point more stable and more accurate.

[0020] In some embodiments, the disconnection detection circuit further includes a second detection branch, wherein: the second detection branch is connected between the first detection point and the second sampling port of the control circuit, and is used to detect the first voltage at the first detection point; the control circuit is used to control the power supply circuit to be in an open state when the device is being charged by the charging device, and to perform disconnection detection between the ground wire of the device and the ground wire of the charging device based on the first voltage obtained by the second sampling port and the bias voltage obtained by the first sampling port.

[0021] By employing the aforementioned technical methods, including adding a second sampling port to acquire the first voltage, and combining this with the bias voltage for comprehensive judgment, the reliability and accuracy of open circuit detection are further improved. Compared to a scheme using only one bias voltage, multi-signal collaborative analysis enhances diagnostic capabilities and reduces the false positive rate.

[0022] In some embodiments, the control circuit is further configured to determine that there is no open circuit fault between the ground wire of the electrical device and the ground wire of the charging device when the amplitude of the first voltage is within a third preset range and the amplitude of the bias voltage is outside a second preset range; and to determine that there is an open circuit fault between the ground wire of the electrical device and the ground wire of the charging device when the amplitude of the bias voltage is within a second preset range and the amplitude of the first voltage is outside a third preset range.

[0023] By employing the aforementioned technical means and introducing a third preset range, the first voltage can be judged more precisely, thereby enhancing the ability to identify open circuit states. Combining the judgment result of the bias voltage forms a dual verification mechanism, which helps improve the comprehensiveness and robustness of open circuit detection.

[0024] In some embodiments, the open circuit detection circuit further includes a second filter circuit disposed on the second detection branch; wherein: the second filter circuit is used to perform voltage regulation and filtering on the first voltage at the first detection point so that the second sampling port obtains a first voltage that satisfies the second condition.

[0025] By employing the aforementioned technical means and adding a second filter circuit before the second sampling port, the quality of the first voltage is further improved, reducing the impact of noise and fluctuations on the judgment result. Compared to the unfiltered case, this enhances signal stability, thereby improving the accuracy of the judgment.

[0026] Secondly, embodiments of this application provide a disconnection detection method applied to a disconnection detection circuit in an electrical device. The disconnection detection circuit includes a power supply circuit, a first detection branch, a bias circuit, and a control circuit. The power supply circuit provides power to a first resistor in a charging device. The first detection branch is connected between a first detection point and a first sampling port of the control circuit, and the bias circuit is disposed on the first detection branch. When the electrical device is being charged by the charging device, the disconnection detection method includes:

[0027] The control circuit controls the power supply circuit to be in an open state and obtains the bias voltage provided by the bias circuit through the first sampling port; based on the bias voltage, the disconnection detection is performed between the ground wire of the electrical equipment and the ground wire of the charging device.

[0028] By employing the aforementioned technical methods, a bias circuit is used to bias the first voltage, thereby converting any potential negative voltage signal into a positive voltage signal input to the control circuit. This ensures that the control circuit can accurately acquire the first voltage signal at the first detection point, regardless of whether it is positive or negative, eliminating signal loss and improving the reliability of open circuit detection. Furthermore, by keeping the power supply circuit disconnected during charging, the influence of the charging current on the ground wire open circuit detection is avoided, further enhancing detection accuracy.

[0029] In some embodiments, when the disconnection detection circuit further includes a second detection branch, the second detection branch is connected between the first detection point and the second sampling port of the control circuit; the disconnection detection method further includes: controlling the power supply circuit to be in an open state, and obtaining a first voltage at the first detection point through the second sampling port; and performing disconnection detection between the ground wire of the electrical device and the ground wire of the charging device based on the bias voltage and the first voltage.

[0030] By employing the aforementioned technical methods, and by adding a second sampling port to acquire the first voltage, a comprehensive judgment is made by combining the bias voltage and the first voltage, further improving the reliability and accuracy of open circuit detection. Compared to a scheme using only one bias voltage, multi-signal collaborative analysis enhances diagnostic capabilities and reduces the false positive rate.

[0031] In some embodiments, when the disconnection detection circuit further includes a third detection branch, the third detection branch is connected between the second detection point and the third sampling port of the control circuit; the disconnection detection method further includes: the control circuit controlling the power supply circuit to be in an open state, and obtaining a first sampling signal through the second sampling port and a third sampling signal through the third sampling port; the control circuit controlling the power supply circuit to be in a connected state, and obtaining a second sampling signal through the second sampling port and a fourth sampling signal through the third sampling port; and performing disconnection detection between the ground wire of the electrical equipment and the ground wire of the charging device based on the first sampling signal, the third sampling signal, the second sampling signal and the fourth sampling signal.

[0032] By employing the aforementioned technical means and adding a third detection branch, dual disconnection detection can be performed between the ground wire of the electrical equipment and the ground wire of the charging device using the sampling signals from the third sampling port of the control circuit, the sampling signals from the second sampling port of the control circuit, and the closed and open states of the disconnection detection switch. For example, by changing the operating state of the power supply circuit and combining the signal changes of the first, third, second, and fourth sampling signals before and after the switching of the operating state of the power supply circuit, it can be determined whether there is a disconnection between the ground wire of the electrical equipment and the ground wire of the charging device. This not only makes the judgment logic simple and easy to implement, but also improves the accuracy of the disconnection detection circuit.

[0033] In some embodiments, based on a first sampling signal, a third sampling signal, a second sampling signal, and a fourth sampling signal, a disconnection detection is performed between the ground wire of the electrical device and the ground wire of the charging device, including: determining that there is a disconnection fault between the ground wire of the electrical device and the ground wire of the charging device when the first sampling signal, the third sampling signal, the second sampling signal, and the fourth sampling signal are all at a first level; and determining that the charging switch between the electrical device and the charging device is open when the first sampling signal, the third sampling signal, and the fourth sampling signal are all at the first level and the second sampling signal is at a second level.

[0034] By employing the aforementioned technical means, and through the signal changes of the first, third, second, and fourth sampling signals before and after the switch for the open circuit detection switch is switched, it is possible to distinguish between an open circuit fault between the ground wire of the electrical device and the ground wire of the charging device, and between an open charging switch between the electrical device and the charging device. Distinguishing between these fault types facilitates targeted maintenance by repair personnel. Thirdly, embodiments of this application provide a charging system comprising a charging device and an electrical device, wherein the electrical device and the charging device are connected, and the electrical device includes the open circuit detection circuit described in the first aspect.

[0035] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of this application. Attached Figure Description

[0036] Figure 1 This is a detailed structural diagram of a charging system provided in an embodiment of this application;

[0037] Figure 2 This is a simplified structural diagram of a charging system provided in an embodiment of this application;

[0038] Figure 3 This is a schematic diagram of a wire breakage detection circuit in related technologies;

[0039] Figure 4 A schematic diagram of a wire breakage detection circuit provided in this application embodiment. Figure 1 ;

[0040] Figure 5 A schematic diagram of a wire breakage detection circuit provided in this application embodiment. Figure 2 ;

[0041] Figure 6 A schematic diagram of a wire breakage detection circuit provided in this application embodiment. Figure 3 ;

[0042] Figure 7A schematic diagram of a wire breakage detection circuit provided in this application embodiment. Figure 4 ;

[0043] Figure 8 A schematic diagram of a wire breakage detection circuit provided in this application embodiment. Figure 5 ;

[0044] Figure 9 A schematic flowchart illustrating a wire breakage detection method provided in an embodiment of this application;

[0045] Figure 10 A schematic diagram of a wire breakage detection circuit provided in this application embodiment. Figure 4 ;

[0046] Figure 11 A schematic diagram of a wire breakage detection circuit provided in this application embodiment. Figure 5 .

[0047] It should be noted that the terms "first" and "second" mentioned above are only used to distinguish between different options and do not represent the degree of superiority or inferiority of the options or their priority in the implementation process. Detailed Implementation

[0048] In order to gain a more detailed understanding of the features and technical content of the embodiments of this application, the implementation of the embodiments of this application will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for reference and illustration only and are not intended to limit the embodiments of this application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0050] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0051] It should also be noted that the terms "first, second, and third" used in the embodiments of this application are only used to distinguish similar objects and do not represent a specific order of objects. It is understood that "first, second, and third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.

[0052] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0053] The following is a description of the relevant technologies used in this application.

[0054] Currently, new energy batteries are being used more and more widely in daily life and industry. They are not only used in energy storage systems for hydropower, thermal power, wind power, and solar power plants, but also extensively in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in aerospace and other fields. With the continuous expansion of the application areas of power batteries, the market demand is also constantly increasing.

[0055] In this embodiment, the battery can be a single battery cell or a battery pack composed of multiple battery cells. A single battery cell refers to a basic unit (or "cell") capable of converting chemical energy into electrical energy, and can be used to manufacture battery modules or battery packs to supply power to electrical devices. A single battery cell can be a rechargeable battery, which is a battery cell that can be recharged after discharge to reactivate its active materials and continue to be used. A single battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and is not limited to any particular type.

[0056] In this embodiment, the battery may also be a single physical module comprising one or more battery cells to provide higher voltage and capacity. When there are multiple battery cells, they can be connected in series, parallel, or mixed via a busbar.

[0057] To facilitate understanding of the technical solutions of the embodiments of this application, the relevant technologies or terms of the embodiments of this application are described below. The following relevant technologies or terms are optional solutions and can be combined with the technical solutions of the embodiments of this application in any way, and all of them fall within the protection scope of the embodiments of this application.

[0058] Figure 1 A detailed structural schematic diagram of a charging system provided in an embodiment of this application is shown below. Figure 1As shown, the charging system includes a charger 10, a charging device 20, and a power-consuming device 30. The output of the charger 10 and the charging device 20 consists of nine wires: DC power supply lines: DC+ and DC-; device ground: PE; charging communication lines: S+ and S-; charging connection confirmation lines: first connection confirmation terminal CC1 and second connection confirmation terminal CC2; and low-voltage auxiliary power supply lines: A+ and A-.

[0059] This charging system complies with relevant national standards, such as GB / T18487.5-2024. Specifically, this charging system can be exemplarily a charging system formed by a charging pile and a vehicle; for example, charger 10 can be exemplarily a charging pile, charging device 20 can be exemplarily a charging gun, and electrical equipment 30 can be exemplarily a vehicle (e.g., an electric vehicle). Therefore, this charging system can also be referred to as a "DC charging control and guidance circuit".

[0060] The first connection confirmation terminal (1st Charging Connection, CC1) is used to confirm the charging connection and can be detected by the charging pile to check the reliability of the charging connection. The second connection confirmation terminal (CC2) is also used to confirm the charging connection and can be detected by the vehicle, similarly to confirm the reliability of the charging connection. Additionally, K1 and K2 are DC power supply circuit contactors, K5 and K6 are charging circuit contactors, K3 and K4 are low-voltage auxiliary power supply circuit contactors, and the charging switch S is closed when charging is required.

[0061] like Figure 1 As shown, the charger 10 also includes a two-stage converter 101, a current measurement circuit 102, a fuse 103, a discharge circuit 104, a first insulation detection circuit 105, a voltage measurement circuit 106, a control power supply 107, and a non-vehicle-mounted charger controller 108; the electrical equipment 30 also includes a control circuit 301A, a power battery 302, and a second insulation detection circuit 303, with specific connections as shown in the diagram. Figure 1 As shown.

[0062] The two-stage converter 101 includes an AC to DC module (which can be simplified as an "AC / DC module"), a transformer T, a DC to DC module (which can be simplified as a "DC / DC module"), and a diode D1. The transformer T is connected between the output side of the AC / DC module and the input side of the DC / DC module. The output side of the DC / DC module is connected to the current measurement circuit 102 through the diode D1. The current measurement circuit 102 is connected to the DC power supply circuit contactor K1 via the fuse 103. The first terminal of the discharge circuit 104 and the first terminal of the first insulation detection circuit 105 are both connected to the connection between the fuse 103 and the DC power supply circuit contactor K1. The second terminal of the discharge circuit 104 and the second terminal of the first insulation detection circuit 105 are both connected to the connection between the output side of the DC / DC module and the DC power supply circuit contactor K2. The third terminal of the first insulation detection circuit 105 is connected to the ground of the charging device. The first terminal of the voltage measurement circuit 106 is connected to the connection between the DC power supply circuit contactor K1 and the DC power line DC+. The second terminal of the voltage measurement circuit 106 is connected to the connection between the DC power supply circuit contactor K2 and the DC power line DC-. In addition, the first absorption circuit RCD1 is connected to the input side of the two-stage converter 101, and the second absorption circuit RCD2 is connected between the input side of the two-stage converter 101 and the control power supply 107; the low-voltage auxiliary power supply circuit contactors K3 and K4 are respectively connected between the output terminal of the control power supply 107 and the control circuit 301A. The control power supply 107 is connected to the off-board charger controller 108. The off-board charger controller 108 is used to provide control signals for controlling the on and off of the low-voltage auxiliary power supply circuit contactors K3, K4, K1, K2 and S1. The off-board charger controller 108 is connected to the control circuit 301A in the electrical equipment 30 through the charging communication lines S+ and S- respectively. The off-board charger controller 108 is also connected to the control circuit 301A in the electrical equipment 30 through the first connection confirmation terminal CC1.

[0063] like Figure 1As shown, in the electrical equipment 30, the positive terminal of the power battery 302 is connected to the DC power line DC+, and the negative terminal of the power battery 302 is connected to the DC power line DC-; a ​​charging circuit contactor K5 is connected in series on the connection between the positive terminal of the power battery 302 and the DC power line DC+; a charging circuit contactor K6 is connected in series on the connection between the negative terminal of the power battery 302 and the DC power line DC-; the first terminal of the second insulation detection circuit 303 is connected to the connection between the positive terminal of the power battery 302 and the charging circuit contactor K5, the second terminal of the second insulation detection circuit 303 is connected to the connection between the negative terminal of the power battery 302 and the charging circuit contactor K6, and the third terminal of the second insulation detection circuit 303 is connected to the ground of the electrical equipment. In addition, switch S2 is connected between the ground of the electrical equipment and the first end of resistor R4, and the second end of resistor R4 is connected to detection point 2; resistor R6 is connected in parallel across the two ends of switch S2, and control circuit 301A is also used to provide control signals for controlling the on and off states to charging circuit contactor K5, charging circuit contactor K6, switch S2 and disconnection detection switch S3.

[0064] For example, the charging control process is roughly as follows:

[0065] 1. When the vehicle plug is plugged into the vehicle socket, the vehicle is in a state where it cannot be driven.

[0066] 2. Vehicle interface connection confirmation:

[0067] When the off-board charger controller 108 controls switch S1 and the control circuit 301A controls switch S2, the voltage of the charging pile monitoring detection point 3 is closed. Detection point 3 is connected to the charging power supply U1 through pull-up resistor R3. The voltage of the charging power supply U1 is 12V. The charging switch S is a normally closed contact.

[0068] When the charging gun is inserted into the socket, switches S1 and S2 are closed. If charging switch S is not pressed at this time, it is closed, and pull-up resistors R3 and R4 are connected in series to form a closed circuit. At this time, the voltage at detection point 3 is U1 × R3 / (R3 + R4). For example, if the charging power supply U1 is 12V, it becomes 6V due to the circuit change. With resistor R4 being 1000 ohms and pull-up resistor R3 being 2000 ohms, the voltage at detection point 3 is 8V. If charging switch S is pressed, it is open, and no circuit is formed. The voltage at detection point 3 is the voltage across charging power supply U1, which is 12V.

[0069] 3. Self-test of off-board charger:

[0070] Once the vehicle interface is fully connected, the charging pile closes K3, K4, K1, and K2 to perform an insulation test. After the test is complete, it disconnects the first insulation test circuit 105, K1, and K2, and begins periodically sending communication handshake messages. If the vehicle requires low-voltage auxiliary power, it needs to wait to see if low-voltage auxiliary power is received; otherwise, it does not need to wait. In any case, the voltage at detection point 1 is used to determine whether the vehicle interface is fully connected.

[0071] Detection point 1 is connected to the first power supply U2 via the first pull-up resistor R5. The first power supply U2 is, for example, 12V, and the first pull-up resistor R5 is, for example, 1000 ohms. When the vehicle interface is not connected, the voltage at detection point 1 is 12V. After connection, the first resistor R1 is connected to the circuit, and the first resistor R1 is 1000 ohms. The voltage at detection point 1 = U2 × R5 / (R5 + R1), therefore, the voltage at detection point 1 is 6V. When the voltage at detection point 1 is 6V, the "vehicle control device" (i.e., control circuit 301A) begins periodically sending communication handshake messages.

[0072] 4. Charging ready:

[0073] The vehicle control unit closes K5 and K6 to connect the charging circuit. Note that K1 and K2 are not closed at this time, so charging cannot begin. When the charging station obtains a battery voltage error less than the set error (e.g., 5%) via communication messages, and the voltage is between the minimum and maximum output voltage of the charging station, K1 and K2 are closed to start charging.

[0074] 5. During the charging process (also known as the charging stage):

[0075] The charging current is not constant during the charging phase. The vehicle control unit sends battery charging demand parameters to the charging station in real time, and the charging station adjusts the charging voltage and current accordingly. It's important to note that when adjusting the current decrease, if the change is less than the set change (e.g., 20A), the charging current should be adjusted to match the command within a maximum of 1 second; if it's greater than 20A, the adjustment should be completed within a maximum of (change / 20) seconds. Simultaneously, the charging station and vehicle exchange their respective status information, as detailed in GB19370. During charging, the vehicle should be able to detect a disconnected PE (protective earth) circuit. "Detecting a disconnected PE circuit" is also referred to as detecting a break in the connection between the ground wire of the electrical equipment 30 and the ground wire of the charging device 20.

[0076] 6. Charging ends under normal conditions:

[0077] For the vehicle, if the vehicle battery is fully charged, or the charging station sends a "stop charging message", the vehicle will periodically send a "vehicle control device stop charging message" to disconnect K5 and K6 after confirming that the charging current is less than the set charging current (e.g., 5A).

[0078] For the charging pile, if the set charging end conditions are met, or the vehicle sends a "stop charging message", the charging pile will periodically send a "charging pile stop charging message" and reduce the charging current. When the charging current is less than 5A, K1 and K2 will be disconnected.

[0079] 7. Charging interruption under abnormal conditions: If the charging pile malfunctions during the charging process, it will periodically send a "charging pile charging interruption message" to the vehicle and disconnect K1, K2, K3, and K4 within 100ms.

[0080] If a vehicle malfunctions during charging, it will periodically send a "vehicle control device to stop charging message" to the charging station. Within 300ms, it will disconnect K5 and K6.

[0081] If a communication timeout occurs during charging, charging will stop and K1, K2, K5, and K6 will be disconnected within 10 seconds. If three communication timeouts occur, communication interruption will be confirmed, charging will stop, and K1-K6 will be disconnected.

[0082] During charging, the voltage at detection point 3 is monitored. If the vehicle interface changes from fully connected to disconnected, charging is stopped, and K1-K4 are disconnected within 100ms. If the charging switch S changes from closed to open, the output current is reduced to 5A or below within 50m.

[0083] If the charging pile output voltage exceeds the vehicle's maximum allowable voltage during the charging process, the charging pile will stop charging within 1 second and disconnect K1-K4.

[0084] As described above, during charging, the vehicle should be able to detect a disconnection of the PE (protective earth) circuit. When a PE disconnection occurs, such as... Figure 2 As shown, since the disconnection detection switch S3 is open during the charging process, the voltage at detection point 1 is the PE potential (i.e., U1). - This is equivalent to 0V, and the voltage at GND is U1. + Therefore, at this time, the voltage at detection point 1 and the voltage between GND = 0 - U1 + =-U1, for example, the voltage of the charging power supply U1 is 12V, then the voltage between the voltage at detection point 1 and GND is -12V (that is, the rated voltage value of the charging power supply U1 as defined by the standard).

[0085] Figure 3 This is a schematic diagram of a wire breakage detection circuit in related technologies, such as... Figure 3As shown, the voltage signal at detection point 1 is filtered by the second filter circuit 301D and then directly fed to the second sampling port ADC2 of the control circuit 301A for sampling. Under normal charging conditions, the voltage at detection point 1 is CC2-GND, which is calculated as a positive voltage. By sampling through the control circuit 301A, the resistance value of the first resistor R1 can be deduced to determine whether the first resistor R1 is currently a charging resistor or a discharging resistor. When a PE circuit is broken, the voltage at detection point 1 is CC2-GND, which is calculated as a negative voltage, such as -12V. This circuit cannot perform negative voltage sampling, and the sampled value remains 0. The sampling signal will be lost under the PE circuit broken state. Therefore, this scheme cannot detect whether a PE line break has occurred.

[0086] Based on this, in order to solve the above problems, this application provides the following disconnection detection circuit, applied to an electrical device, including a power supply circuit, a first detection branch, a bias circuit, and a control circuit, wherein: the power supply circuit is used to provide power to a first resistor in a charging device; the first detection branch is connected between a first detection point and a first sampling port of the control circuit, and is used to detect a first voltage at the first detection point; the bias circuit is disposed on the first detection branch, and is used to bias the first voltage at the first detection point and provide a bias voltage to the first sampling port of the control circuit; the control circuit is used to control the power supply circuit to be in an open state when the electrical device is being charged by the charging device, and to perform disconnection detection between the ground wire of the electrical device and the ground wire of the charging device based on the bias voltage obtained from the first sampling port. In this way, power is supplied to the first resistor in the charging device through the power supply circuit. The first voltage at the first detection point is collected by the first detection branch, and the first voltage is biased by the bias circuit, thereby converting any possible negative voltage signal into a positive voltage signal input to the control circuit. This ensures that the control circuit can accurately collect the first voltage signal at the first detection point, regardless of whether it is a positive or negative voltage signal, without signal loss, thus improving the reliability of the open circuit detection. The control circuit can detect the open circuit between the ground wire of the electrical equipment and the ground wire of the charging device through the bias voltage. This design overcomes the problem that existing circuits cannot directly sample negative voltage, achieving effective detection of the open circuit between the ground wire of the electrical equipment and the ground wire of the charging device. The open circuit detection circuit has a simple structure, which can reduce costs. In addition, the control power supply circuit is kept in an open state during charging, avoiding the influence of the charging current on the open circuit detection between the ground wires, thus improving the accuracy of the detection.

[0087] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0088] In one embodiment of this application, Figure 4A schematic diagram of a wire breakage detection circuit provided in this application embodiment. Figure 1 ,like Figure 4 As shown, the disconnection detection circuit 301 is applied to the electrical equipment 30. The disconnection detection circuit 301 includes: a power supply circuit, a first detection branch, a bias circuit 301B, and a control circuit 301A.

[0089] Specifically, the power supply circuit is used to provide power to the first resistor R1 in the charging device 20; the first detection branch is connected between the first detection point and the first sampling port ADC1 of the control circuit 301A, and is used to detect the first voltage at the first detection point; the bias circuit 301B is set on the first detection branch, and is used to bias the first voltage at the first detection point and provide a bias voltage to the first sampling port ADC1 of the control circuit 301A.

[0090] The control circuit 301A is used to control the power supply circuit to be in an open state when the power device 30 is being charged by the charging device 20, and to detect the disconnection between the ground wire of the power device 30 and the ground wire of the charging device 20 based on the bias voltage obtained by the first sampling port ADC1.

[0091] The first detection point can also be called detection point 1.

[0092] It should be noted that the bias circuit 301B biases the first voltage at the first detection point and outputs it to the first sampling port ADC1. The first sampling port ADC1 obtains the first bias voltage, which can also be called the bias voltage.

[0093] Understandably, in this embodiment, by setting a bias circuit to bias the first voltage, any possible negative voltage signal is converted into a positive voltage signal and input to the control circuit. This ensures that the control circuit can accurately acquire the signal regardless of whether the first voltage at the first detection point is positive or negative, eliminating signal loss and improving the reliability of the open circuit detection. Furthermore, by keeping the power supply circuit disconnected during charging, the influence of the charging current on the ground wire open circuit detection is avoided, further improving detection accuracy.

[0094] As an optional embodiment, the power supply circuit may include a first power supply U2 and a disconnection detection switch S3.

[0095] Specifically, the first power supply U2 and the disconnection detection switch S3 are connected in series, and the first detection point is set between the disconnection detection switch S3 and the first resistor R1.

[0096] At this time, the control circuit 301A is also used to control the disconnection detection switch S3 to open when the power supply circuit is being charged by the charging device 20 to the electrical equipment 30, so that the power supply circuit is in a disconnected state.

[0097] For example, the open circuit detection switch S3 is an electronic component that can switch the on / off state according to the control signal. It can typically be a switching transistor, a relay, or a metal-oxide-semiconductor field-effect transistor (MOSFET), etc.

[0098] It is understood that in this embodiment, the state of the power supply circuit is controlled by controlling the on / off state of the disconnection detection switch, making the disconnection of the power supply circuit more reliable.

[0099] As an optional embodiment, the power supply circuit may further include a first pull-up resistor R5. Specifically, the first pull-up resistor R5 is connected in series on the connection line between the first power supply U2 and the disconnection detection switch S3.

[0100] Understandably, the first pull-up resistor R5 ensures that the input of the disconnection detection switch S3 remains at a stable high level when there is no external signal input, thus avoiding misjudgments caused by floating. For example, in a DC charging system for electric vehicles, when the PE (protective earth) line is broken, the disconnection detection switch S3 may make an incorrect judgment because it does not receive a clear control signal. By introducing the first pull-up resistor R5, it can be ensured that the disconnection detection switch S3 maintains a predictable state even without external signal input, thereby improving the stability and reliability of the system.

[0101] It is understandable that, in this embodiment, adding a first pull-up resistor can make the opening or closing of the disconnection detection switch more stable, improve the anti-interference capability of the disconnection detection switch, and make the sampling of the first voltage at the first sampling point more stable and more accurate.

[0102] Under normal conditions (i.e., when the PE line is not broken), the voltage at detection point 1 (i.e., the voltage at the second connection confirmation terminal CC2) is positive relative to ground. However, if the PE line is broken, the sampled voltage from the second connection confirmation terminal may be negative. If this negative voltage is input to the first sampling port ADC1 of the control circuit 301A, the analog-to-digital converter in the control circuit 301A may fail to recognize the negative voltage signal at the first sampling port ADC1. Therefore, the bias circuit 301B can convert this negative voltage signal into a positive voltage signal, enabling the control circuit 301A to correctly recognize and process the positive voltage signal.

[0103] In some embodiments, the bias circuit 301B may include a first bias branch and a second bias branch.

[0104] Specifically, the second bias branch is set on the first detection branch; the first bias branch is conveniently located between the power supply circuit and the first bias branch.

[0105] It is understood that, in this embodiment, the two bias branches enable the bias circuit to have greater flexibility and adaptability, and can more effectively adjust the voltage at the detection point to meet the sampling requirements of different application scenarios.

[0106] In some embodiments, the bias branch typically consists of several resistors, and the voltage division ratio of the bias circuit 301B can be adjusted as needed to achieve bias processing of the input voltage. For example, assuming the voltage at the second connection confirmation terminal CC2 (i.e., the voltage at detection point 1) is -12V, the voltage at the second connection confirmation terminal CC2 can be boosted to approximately +5V in the bias circuit by appropriately selecting the resistor value, thereby meeting the input range requirements of the first sampling port ADC1 in the control circuit 301A.

[0107] Understandably, the design of the bias circuit 301B should accommodate both positive and negative voltage sampling requirements. Under normal charging conditions, the voltage at the second connection confirmation terminal CC2 is positive. In this case, the bias circuit ensures that the voltage at CC2 remains constant or is slightly amplified to improve sampling accuracy. However, when the PE circuit is open, the voltage at CC2 becomes negative. Therefore, the bias circuit 301B needs to convert the voltage at CC2 back to positive to ensure that the control circuit 301A can accurately identify the voltage.

[0108] Understandably, the control circuit 301A should be set to a suitable range so that the magnitude of the bias voltage obtained through the first sampling port ADC1 can distinguish between normal conditions and PE disconnection conditions.

[0109] In practical implementation, the design of the bias circuit 301A should take into account the overall sampling accuracy and stability of the system. For example, high-precision resistors can be selected to reduce sampling errors. Furthermore, the output of the bias circuit 301B can be compensated through software calibration to further improve detection accuracy.

[0110] As an optional embodiment, such as Figure 6 and Figure 7 As shown, the first bias branch provided in this application embodiment includes a first bias resistor R7, and the second bias branch includes a second bias resistor R8.

[0111] The second bias resistor R8 is set on the first detection branch; the first bias resistor R7 is connected across the power circuit and the second bias resistor R8.

[0112] Specifically, the first end of the first bias resistor R7 is connected to the positive terminal of the first power supply U2; the first end of the second bias resistor R8 is connected to the second connection confirmation terminal CC2 (i.e., the first detection point); and the second end of the first bias resistor R7 is connected to the second end of the second bias resistor R8 and the first sampling port ADC1.

[0113] Understandably, the first terminal of the first bias resistor R7 is connected to the positive terminal of the first power supply U2, providing a reference voltage for the entire bias circuit 301B. The connection between the first terminal of the first bias resistor R7 and the positive terminal of the first power supply U2 ensures that the bias circuit 301B has a stable reference point during normal operation, which helps maintain the accuracy of the sampling voltage.

[0114] By setting up a bias circuit 301B including a first bias resistor R7 and a second bias resistor R8, the negative voltage signal at the second connection confirmation terminal CC2 is converted into a positive voltage input, thereby achieving reliable detection of PE open circuit faults. This overcomes the misjudgment problem caused by the inability to collect negative voltage signals in related technologies, thereby improving the safety and reliability of DC charging systems and meeting the requirements of national standard GB / T18487.5-2024, realizing high-precision fault diagnosis function for electric vehicles during the charging process.

[0115] Understandably, in this embodiment, a voltage divider structure composed of two bias resistors is used to adjust the bias of the first voltage at the first detection point, ensuring that its output is a positive signal. This simple and reliable resistor voltage divider method is easy to implement and low in cost, while also being able to stably convert negative voltage to positive voltage, improving the stability of the sampling signal and facilitating the design of the control circuit's judgment logic.

[0116] As an optional embodiment, such as Figure 5 As shown, the open circuit detection circuit 301 provided in this application embodiment may further include a first filter circuit 301C.

[0117] Specifically, the first filter circuit 301C is disposed on the connection line between the bias circuit 301B and the first sampling port ADC1.

[0118] The first filter circuit 301C is used to regulate and filter the bias voltage so that the first sampling port ADC1 obtains a bias voltage that meets the first condition.

[0119] In some alternative embodiments, the bias voltage that satisfies the first condition can be a smooth bias voltage after filtering out interference and eliminating glitches.

[0120] It is understood that in this embodiment, adding a first filter circuit between the bias circuit and the control circuit can effectively remove noise and fluctuations in the bias voltage, improving the stability and accuracy of the bias voltage. Compared to the unfiltered solution, this reduces false positives and improves the accuracy and reliability of open circuit detection.

[0121] In one embodiment, continue as follows Figure 6 and Figure 7 As shown, the first filter circuit 301C in the disconnection detection circuit 301 provided in this application embodiment may include a first filter resistor R11 and a first filter capacitor C4.

[0122] Specifically, the first filter resistor R11 is connected in series between the second end of the second bias resistor R8 and the first sampling port ADC1; the anode plate of the first filter capacitor C4 is connected to the end of the first filter resistor R11 used for connecting to the first sampling port ADC1, and the cathode plate of the first filter capacitor C4 is grounded.

[0123] In one optional embodiment, the ground connected to the cathode plate of the first filter capacitor C4 can be a separately set ground potential; in another optional embodiment, for the purpose of simplifying the wiring and facilitating cabling, it can be the ground wire GND of the electrical device 30. This application does not impose any particular limitation on this, and the following description will take the example of the ground wire GND of the electrical device 30 being connected to the cathode plate of the first filter capacitor C4 as an example.

[0124] like Figure 6 As shown, specifically, the control circuit 301A is also used to determine that there is no open circuit fault between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20 when the amplitude of the bias voltage is within a first preset range; and to determine that there is an open circuit fault between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20 when the amplitude of the bias voltage is within a second preset range.

[0125] The lower limit of the first preset range is higher than the upper limit of the second preset range.

[0126] For example, the second preset range is (0V, 1V) and the first preset range is (1V, 3V).

[0127] Understandably, the amplitude of the bias voltage reflects the state of the PE (protective earth) conductor. When the PE conductor is normally connected, the voltage at detection point 1 is positive relative to GND; however, when the PE conductor is open-circuited, the voltage at detection point 1 will become negative (e.g., -12V). This is one of the characteristics for judging PE open-circuit faults as defined in standard GB / T18487.5-2024. Therefore, this characteristic can be used to distinguish between normal and PE open-circuit states by setting the bias circuit 301B and reasonable first and second preset ranges.

[0128] Understandably, the first preset range represents the voltage range under normal conditions, i.e., the state where the ground wire is well connected; the second preset range represents the voltage range under abnormal conditions, i.e., the state where the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 30 may be disconnected.

[0129] Since the lower limit of the first preset range is higher than the upper limit of the second preset range, there is no overlap between the two, ensuring the uniqueness and accuracy of the judgment result. By setting different voltage threshold ranges to distinguish whether the protective grounding wire (PE wire) has been broken, the control circuit can quickly determine whether a PE wire open circuit fault has occurred based on the amplitude change of the sampled bias voltage.

[0130] Exemplarily, in an optional embodiment, the bias circuit 301B can be directly set as follows: Figure 3 In one of the related technologies shown, a broken wire detection circuit is used to overcome, for example... Figure 3 The circuit shown can solve the problem of not being able to collect a signal at detection point 1 when the PE is broken. It can also save circuit components and reduce costs.

[0131] Specifically, the first terminal of the bias circuit 301B can be connected to the positive terminal of the first power supply U2, and the other two terminals of the bias circuit 301B can be connected to the line between detection point 1 and the second filter circuit 301D. That is, the second terminal of the bias circuit 301B is connected to detection point 1 (also called the second connection confirmation terminal CC2), and the third terminal of the bias circuit 301B is connected to the end of the second filter circuit 301D that was originally used to connect to detection point 1. In this way, the bias circuit 301B can also convert the negative voltage collected at detection point 1 into a positive voltage, so that the second sampling port ADC2 can collect the first voltage at detection point 1 whether in normal state or when the PE line is disconnected. The first voltage at detection point 1 is output to the second sampling port ADC2 after passing through the bias circuit 301B, and the second sampling port ADC2 obtains the second bias voltage.

[0132] For example, the normal state and the PE disconnection state can be distinguished by a first preset range and a second preset range. That is, when the amplitude of the second bias voltage is within the first preset range, it is determined that there is no disconnection fault between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20; when the amplitude of the second bias voltage is within the second preset range, it is determined that there is a disconnection fault between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20.

[0133] Understandably, in this embodiment, different amplitude thresholds are set to distinguish between normal and open circuit states, thus achieving automatic judgment of whether there is an open circuit fault between ground wires. On the other hand, compared with the traditional method of judging solely by a single voltage value, dividing the data into multiple threshold ranges improves the flexibility and accuracy of the judgment, avoiding misjudgments caused by system errors or environmental interference.

[0134] As an optional embodiment, such as Figure 7 As shown, the open circuit detection circuit 301 may also include a second detection branch.

[0135] Specifically, the second detection branch is connected between the first detection point (i.e., detection point 1) and the second sampling port ADC2 of the control circuit 301A, and is used to detect the first voltage at the first detection point.

[0136] The control circuit 301A is used to control the power supply circuit to be in an open state (e.g., control the disconnection detection switch S3 to be open) when the device 30 is being charged by the charging device 20, and to detect the disconnection between the ground wire of the device 30 and the ground wire of the charging device 20 based on the first voltage obtained by the second sampling port ADC2 and the bias voltage obtained by the first sampling port ADC1.

[0137] It is understandable that, such as Figure 7 The circuit scheme for detecting broken wires shown is as follows: Figure 6 In the aforementioned disconnection detection circuit design, an additional sampling signal is added at the second connection confirmation terminal CC2. This additional sampling signal can be as follows: Figure 3 The schematic diagram of a broken wire detection circuit in the related technology shown includes the original sampling signal channel.

[0138] Understandably, if we take Figure 3 The proposed solution is for reference only and can also be understood as a solution to problems such as... Figure 3In the scheme shown, it is impossible to collect the negative voltage at detection point 1 when the PE is broken. Therefore, a bias circuit 301B is added to make the negative voltage at detection point 1 become a positive voltage, so as to ensure that the first sampling port ADC1 of the control circuit 301A can collect a positive bias voltage. Based on the bias voltage and the first voltage, the break between the ground wire of the electrical equipment 30 and the ground wire PE of the charging device 20 is detected.

[0139] It is understandable that in this embodiment, by adding a second sampling port and acquiring the first voltage, and combining it with the bias voltage for comprehensive judgment, the reliability and accuracy of the open circuit detection are further improved. Compared with a scheme that uses only one bias voltage, the multi-signal collaborative analysis enhances the diagnostic capability and reduces the false positive rate.

[0140] Continue as Figure 7 As shown, specifically, the control circuit 301A is further configured to determine that there is no open circuit fault between the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20 when the amplitude of the first voltage is within a third preset range and the amplitude of the bias voltage is outside a second preset range; and to determine that there is an open circuit fault between the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20 when the amplitude of the bias voltage is within a second preset range and the amplitude of the first voltage is outside a third preset range.

[0141] It is understandable that if the amplitude of the first voltage is outside the third preset range, the first voltage cannot be collected. In this case, it can be represented by "0". This application does not make any special restrictions on this.

[0142] It is understandable that, in this embodiment, by introducing a third preset range, the first voltage is judged more precisely, thereby enhancing the ability to identify the open circuit state. Combining the judgment result of the bias voltage forms a dual verification mechanism, which helps to improve the comprehensiveness and robustness of the open circuit detection.

[0143] As another alternative embodiment, continue as follows Figure 7 As shown, the open circuit detection circuit 301 provided in this embodiment may further include a second filter circuit 301D. The second filter circuit 301D is disposed on the second detection branch.

[0144] Specifically, the second filter circuit 301D is disposed on the connection line between the second connection confirmation terminal CC2 and the second sampling port ADC2. The second filter circuit 301D is used to regulate and filter the first voltage at the first detection point so that the second sampling port ADC2 obtains a first voltage that satisfies the second condition.

[0145] In some alternative embodiments, the first voltage that satisfies the second condition may be a smooth first voltage after filtering out interference and eliminating glitches.

[0146] Understandably, the second filter circuit 301D can reduce the impact of high-frequency noise, fluctuations, or transient interference during signal transmission, thereby improving the accuracy and stability of the first voltage. The second filter circuit smooths the input voltage, making it closer to the actual voltage value, ensuring high quality of the first voltage entering the control circuit 301A. By adding the second filter circuit 301D, voltage fluctuations caused by electromagnetic interference or other environmental factors can be effectively suppressed, making subsequent sampling processes more reliable.

[0147] In one embodiment, continue as follows Figure 7 As shown, the second filter circuit 301D in the open circuit detection circuit 301 provided in this application embodiment may include a second filter resistor R12 and a second filter capacitor C5.

[0148] Specifically, the second filter resistor R12 is connected in series on the connection line between the second connection confirmation terminal CC2 and the second sampling port ADC2; the anode plate of the second filter capacitor C5 is connected to the end of the second filter resistor R12 that is used to connect to the second sampling port ADC2, and the cathode plate of the second filter capacitor C5 is grounded.

[0149] In one optional embodiment, the ground connected to the cathode plate of the second filter capacitor C5 can be a separately set ground potential; in another optional embodiment, for the purpose of simplifying the wiring and facilitating cabling, it can be the ground wire GND of the electrical device 30. This application does not impose any particular limitation on this, and the following description will exemplify that the ground connected to the cathode plate of the second filter capacitor C5 is the ground wire GND of the electrical device 30.

[0150] It is understood that in this embodiment, by setting a second filter circuit before the second sampling port, the quality of the first voltage is further improved, reducing the impact of noise and fluctuations on the judgment result. Compared with the case without filtering, the stability of the signal is enhanced, thereby improving the accuracy of the judgment.

[0151] It is understandable that by connecting one end of the first resistor R1 to the second end of the open circuit detection switch S3 and grounding the other end, a voltage divider network can be formed, enabling the control circuit 301A to calculate the voltage at detection point 1 based on the voltage difference across the first resistor R1.

[0152] In another embodiment, one end of the first resistor R1 can be connected to the second connection confirmation terminal CC2, and the second connection confirmation terminal CC2 is also connected to the second end of the disconnection detection switch S3.

[0153] The following is based on Figure 6For example, the control circuit 301A can calculate the voltage at detection point 1 based on the voltage difference across the first resistor R1. For example, the resistance value of the first resistor R1 can be 1000 ohms (Ω).

[0154] In one example, if the bias voltage obtained by the first sampling port ADC1 is 1V, then it is assumed that there is a break in the ground wire GND of the power device 30 and the ground wire PE of the charging device 20, and the original voltage at the detection point 1 can be calculated to be -12V.

[0155] In another example, if the bias voltage obtained by the first sampling port ADC1 is 2V, then it is assumed that there is no break between the ground wire GND of the power device 30 and the ground wire PE of the charging device 20, and the original voltage at the detection point 1 can be calculated to be 0V.

[0156] The following is based on Figure 7 For example, the control circuit 301A can calculate the voltage at detection point 1 based on the voltage difference across the first resistor R1. For example, the resistance value of the first resistor R1 can be 1000 ohms (Ω).

[0157] In one example, if the bias voltage obtained by the first sampling port ADC1 is 1V and the second sampling port ADC2 cannot acquire the first voltage, then it is assumed that there is a break in the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20, and the original voltage at the detection point 1 can be calculated to be -12V.

[0158] In another example, if the bias voltage obtained by the first sampling port ADC1 is 2V and the amplitude of the first voltage obtained by the second sampling port ADC2 is within the third preset range, then it is assumed that there is no break between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20, and the original voltage at the detection point 1 can be calculated to be 0V.

[0159] by Figure 7 For example, the positive and negative voltages of CC2-GND use their own independent sampling channels. That is, when CC2-GND is positive, the second sampling port ADC2 is used, and when CC2-GND is negative, the first sampling port ADC1 is used. By configuring the resistance ratio of the first bias resistor R7 and the second bias resistor R8 when sampling negative voltage, and configuring the resistance value of the first pull-up resistor R5 when sampling positive voltage, it is possible to not only ensure that the positive voltage of CC2-GND has a high sampling accuracy under normal conditions, but also to ensure that the sampling range of the negative voltage of CC2-GND will be limited when PE is open.

[0160] It is understandable that the values ​​of the first bias resistor R7, the second bias resistor R8, and the first pull-up resistor R5 are configured to achieve high distinguishability. In current applications, the first resistor R1 has two types of resistance values: one is the resistance value of the charging gun, and the other is the resistance value of the discharging gun. If the distinguishability is low, after considering the sampling accuracy of the entire system, there may be situations where the sampled values ​​cannot accurately represent these two types of resistance values.

[0161] It should be noted that, when the first resistor R1 is also included, the values ​​of the first bias resistor R7 and the second bias resistor R8 are related to the sampling accuracy and sampling range of the first resistor R1.

[0162] In another embodiment of this application, a method for detecting broken wires is also provided, such as... Figure 8 and Figure 9 As shown.

[0163] The wire breakage detection method provided in this embodiment is applied to the wire breakage detection circuit 301 in the electrical equipment 30. The wire breakage detection circuit 301 can, as follows: Figure 8 As shown, the open circuit detection circuit 301 includes a power supply circuit, a first detection branch, a third detection branch, and a control circuit.

[0164] The power supply circuit is used to provide power to the first resistor in the charging device. The first detection branch is connected between the first detection point and the first sampling port of the control circuit, and the third detection branch is connected between the second detection point and the third sampling port of the control circuit.

[0165] When the power supply circuit includes a first power supply U2 and a disconnection detection switch S3: Specifically, the positive terminal of the first power supply U2 is connected to the first terminal of the disconnection detection switch S3, the negative terminal of the first power supply U2 is connected to the ground wire GND of the electrical device 30, the second terminal of the disconnection detection switch S3 is connected to the second connection confirmation terminal CC2 of the electrical device 30, the second connection confirmation terminal CC2 is also connected to the second sampling port ADC2 of the control circuit 301A and the first resistor R1 in the charging device 20 respectively; the other end of the first resistor R1 is connected to the ground wire of the charging device 20; the first connection confirmation terminal CC1 of the electrical device 30 (i.e., the second detection point, also called detection point 2) is connected to the third sampling port ADC3 of the control circuit 301A.

[0166] It is understandable that when the connection confirmation test is performed before the charging device 20 charges the electrical equipment 30, the disconnection detection switch S3 is in the closed state, forming a power supply circuit, and the first power supply U2 supplies power to the first resistor R1.

[0167] In an alternative embodiment, continue as follows Figure 8As shown, the disconnection detection circuit 301 may further include a first filter circuit 301C, and the first filter circuit 301C is disposed on the first detection branch.

[0168] Specifically, the first filter circuit 301C is disposed between the second connection confirmation terminal CC2 and the first sampling port ADC1 of the control circuit 301A.

[0169] like Figure 9 As shown, the charging device 20 charges the electrical equipment 30, and the disconnection detection method includes the following steps:

[0170] S901, the control circuit 301A controls the power supply circuit to be in the off state, and obtains the first sampling signal through the first sampling port ADC1 and the third sampling signal through the third sampling port ADC3.

[0171] For example, the power supply circuit can be kept in an open state by controlling the disconnection detection switch S3 to open.

[0172] S902, the control circuit 301A controls the disconnection detection switch S3 to be in the connected state, and obtains the second sampling signal through the first sampling port ADC1 and the fourth sampling signal through the third sampling port.

[0173] For example, the power supply circuit can be kept in a connected state by controlling the closed circuit detection switch S3.

[0174] S903. Based on the first sampling signal, the third sampling signal, the second sampling signal, and the fourth sampling signal, a disconnection detection is performed between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20.

[0175] It is understandable that, such as Figure 3 In one of the related technologies shown, under normal charging conditions, the voltage at detection point 1 (also known as the first voltage) is positive. The first voltage can be sampled through the second sampling port of the control circuit 301A, and the resistance value of the first resistor R1 can be deduced. However, when a PE circuit breaks, the voltage at detection point 1 is negative. The sampling circuit cannot perform negative voltage sampling, and the sampled value remains at 0. At this time, it is impossible to accurately diagnose whether a PE circuit breaks, because possible reasons include: a PE circuit breaks or the charging switch S between the electrical equipment 30 and the charging device 20 is disconnected.

[0176] To solve this problem, such as Figure 8As shown, the first connection confirmation terminal CC1 (i.e., detection point 2) can be connected to the third sampling port ADC3 of the control circuit 301A. By controlling the opening and closing of the disconnection detection switch S3, and combining the sampling signal of the third sampling port ADC3 of the control circuit 301A and the state change of the sampling signal of the first sampling port ADC1, it can be distinguished whether the PE is disconnected or the charging switch S between the electrical equipment 30 and the charging device 20 is disconnected.

[0177] That is, by controlling the power supply circuit to switch different states, and combining the sampling signals of the third sampling port ADC3 of the control circuit 301A and the sampling signals of the first sampling port ADC1 before and after the state of the power supply circuit is switched, it can be distinguished whether the PE is disconnected or the charging switch S between the power device 30 and the charging device 20 is disconnected.

[0178] In one example, when the first sampling signal, the third sampling signal, the second sampling signal, and the fourth sampling signal are all at the first level, it is determined that there is a break fault between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20.

[0179] In other words, if the sampling signals at the first sampling port ADC1 and the third sampling port ADC3 do not change after the disconnection detection switch S3 switches to the next state, it indicates that there is a disconnection fault between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20.

[0180] In another example, when the first sampling signal, the third sampling signal, and the fourth sampling signal are all at the first level and the second sampling signal is at the second level, it is determined that the charging switch S between the electrical device 30 and the charging device 20 is disconnected.

[0181] In other words, after the disconnection detection switch S3 switches the state of the sampling signal at the first sampling port ADC1 and the sampling signal at the third sampling port ADC3, the level of the sampling signal at the first sampling port ADC1 changes, while the level of the sampling signal at the third sampling port ADC3 does not change. This indicates that the charging switch S between the electrical equipment 30 and the charging device 20 is disconnected.

[0182] The first level state and the second level state are two opposite level states. That is, if the first level state is a high-level signal (for example, a "1" can be used to represent a high-level signal in a digital signal), the second level state is a low-level signal (for example, a "0" can be used to represent a low-level signal in a digital signal); or, if the first level state is a low-level signal, the second level state is a high-level signal. This application does not make any special limitation in this regard, and the following description will take the example of the first level state being a low-level signal and the second level state being a high-level signal.

[0183] It is understood that in this embodiment, by using the signal changes of the first sampling signal, the third sampling signal, the second sampling signal and the fourth sampling signal before and after the switch state of the disconnection detection switch is switched, it is possible to distinguish between the disconnection fault between the ground wire of the electrical equipment and the ground wire of the charging device and the disconnection of the charging switch between the electrical equipment and the charging device. By distinguishing the fault conditions, it is convenient for maintenance personnel to perform targeted maintenance.

[0184] It is understood that in this embodiment, by changing the working state of the power supply circuit and combining the signal changes of the first sampling signal, the third sampling signal, the second sampling signal and the fourth sampling signal before and after the switching of the working state of the power supply circuit, it is possible to determine whether there is a break between the ground wire of the power device and the ground wire of the charging device. This eliminates the need for an additional bias circuit, which saves costs and makes the judgment logic simple and easy to implement.

[0185] It is understood that the wire breakage detection method provided in the embodiments of this application can also be applied to, for example... Figure 6 and Figure 7 In the circuit shown for detecting broken wires.

[0186] In applications such as Figure 6 In the disconnection detection circuit shown, the first connection confirmation terminal CC1 of the electrical device 30 needs to be connected to the third sampling port ADC3 of the control circuit 301A, such as... Figure 10 As shown.

[0187] Specifically, the positive terminal of the first power supply U2 is connected to the first terminal of the disconnection detection switch S3 and the first terminal of the bias circuit 301B, respectively; the negative terminal of the first power supply U2 is connected to the ground wire GND of the electrical equipment 30; and the second terminal of the disconnection detection switch S3 is connected to the second connection confirmation terminal CC2 of the electrical equipment 30.

[0188] In cases where the open circuit detection circuit also includes a bias circuit, the bias circuit 301B is disposed on the first detection branch. The connection relationship between the second connection confirmation terminal CC2 and the first sampling port ADC1 of the control circuit 301A is changed from the original connection between the second connection confirmation terminal CC2 and the first sampling port ADC1 of the control circuit 301A to: the second connection confirmation terminal CC2 is connected to the second terminal of the bias circuit 301B, and the third terminal of the bias circuit 301B is connected to the first sampling port ADC1 of the control circuit 301A.

[0189] The open circuit detection method also includes: controlling the power supply circuit to be in an open state, and obtaining the bias voltage provided by the bias circuit 301B through the first sampling port ADC1; based on the bias voltage, performing open circuit detection between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20.

[0190] For example, the power supply circuit can be disconnected by controlling the disconnection detection switch S3 to open.

[0191] For example, when the amplitude of the bias voltage is within a first preset range, it is determined that there is no open circuit fault between the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20; when the amplitude of the bias voltage is within a second preset range, it is determined that there is an open circuit fault between the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20.

[0192] In another alternative embodiment, the presence of a PE disconnection can be determined by using the sampling signal at the third sampling port ADC3 of the control circuit 301A, the sampling signal at the first sampling port ADC1 of the control circuit 301A, and the closed and open states of the disconnection detection switch S3.

[0193] That is, the control circuit 301A controls the disconnection detection switch S3 to be in the open state, and obtains the fifth sampling signal through the first sampling port ADC1 and the third sampling signal through the third sampling port ADC3; the control circuit 301A controls the disconnection detection switch S3 to be in the closed state, and obtains the sixth sampling signal through the first sampling port ADC1 and the fourth sampling signal through the third sampling port.

[0194] It should be noted that the fifth sampling signal is the bias voltage after analog-to-digital conversion, and it is essentially still the bias voltage.

[0195] In one example, if the fifth, third, sixth, and fourth sampling signals are all at the first level, it is determined that there is an open circuit fault between the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20. In another example, if the fifth, third, and fourth sampling signals are all at the first level and the sixth sampling signal is at the second level, it is determined that the charging switch S between the electrical device 30 and the charging device 20 is open.

[0196] Understandably, in this embodiment, by setting a bias circuit to bias the first voltage, any possible negative voltage signal is converted into a positive voltage signal and input to the control circuit. This ensures that the control circuit can accurately acquire the signal regardless of whether the first voltage at the first detection point is positive or negative, eliminating signal loss and improving the reliability of the open circuit detection. Furthermore, by keeping the power supply circuit disconnected during charging, the influence of the charging current on the ground wire open circuit detection is avoided, further improving detection accuracy.

[0197] In applications such as Figure 7 In the disconnection detection circuit shown, the first connection confirmation terminal CC1 of the electrical device 30 needs to be connected to the third sampling port ADC3 of the control circuit 301A, such as... Figure 11 As shown.

[0198] Specifically, when the disconnection detection circuit 301 also includes a bias circuit 301B, the positive terminal of the first power supply U2 is connected to the first terminal of the disconnection detection switch S3 and the first terminal of the bias circuit 301B, respectively. The negative terminal of the first power supply U2 is connected to the ground wire GND of the electrical device 30. The second terminal of the disconnection detection switch S3 is connected to the second connection confirmation terminal CC2 of the electrical device 30. The second connection confirmation terminal CC2 is connected to the second terminal of the bias circuit 301B. The third terminal of the bias circuit 301B is connected to the first sampling port ADC1 of the control circuit 301A. The second connection confirmation terminal CC2 is also connected to the second sampling port ADC2 of the control circuit 301A.

[0199] The open circuit detection method further includes: controlling the power supply circuit to be in an open state and obtaining a bias voltage through the first sampling port ADC1; obtaining a first voltage at the first detection point through the second sampling port ADC2; and performing open circuit detection between the ground wire GND of the electrical equipment 30 and the ground wire PE of the charging device 20 based on the bias voltage and the first voltage.

[0200] For example, the power supply circuit can be disconnected by controlling the disconnection detection switch S3 to open.

[0201] For example, when the amplitude of the first voltage is within a third preset range and the amplitude of the bias voltage is outside a second preset range, it is determined that there is no open circuit fault between the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20; and when the amplitude of the bias voltage is within a second preset range and the amplitude of the first voltage is outside a third preset range, it is determined that there is an open circuit fault between the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20.

[0202] In another alternative embodiment, the presence of a PE disconnection can be determined by using the sampling signal at the third sampling port ADC3 of the control circuit 301A, the sampling signal at the second sampling port ADC2 of the control circuit 301A, and the closed and open states of the disconnection detection switch S3.

[0203] That is, the control circuit 301A controls the disconnection detection switch S3 to be in the open state, and obtains the first sampling signal through the second sampling port ADC2 and the third sampling signal through the third sampling port ADC3; the control circuit 301A controls the disconnection detection switch S3 to be in the closed state, and obtains the second sampling signal through the second sampling port ADC2 and the fourth sampling signal through the third sampling port.

[0204] It should be noted that the first sampled signal is the signal of the first voltage after analog-to-digital conversion, but it is still essentially the first voltage.

[0205] In one example, if the first, third, second, and fourth sampling signals are all at the first level, it is determined that there is an open circuit fault between the ground wire GND of the electrical device 30 and the ground wire PE of the charging device 20. In another example, if the first, third, and fourth sampling signals are all at the first level, and the second sampling signal is at the second level, it is determined that the charging switch S between the electrical device 30 and the charging device 20 is open.

[0206] It is understood that, since the disconnection detection circuit 301 does not include the bias circuit 301B, but includes the third detection branch in the embodiment, i.e., as... Figure 8 In the embodiment shown, the first sampling port ADC1 of the control circuit 301A is directly connected to the detection point 1 through the first detection branch; while in the embodiment where the disconnection detection circuit 301 includes a bias circuit 301B, a second detection branch, and a third detection branch, i.e., as shown... Figure 11 In the embodiment shown, the second sampling port ADC2 of the control circuit 301A is also directly connected to the detection point 1 through the second detection branch. Therefore, the sampling signal obtained through the second sampling port is... Figure 8The sampling signals obtained through the first sampling port are the same. Therefore, when the disconnection detection switch S3 is in the closed state, as in... Figure 11 In the embodiment shown, the sampling signal obtained by the second sampling port ADC2 of the control circuit 301A can be compared with that obtained by... Figure 8 In the illustrated embodiment, the sampling signals obtained by the first sampling port ADC1 of the control circuit 301A are the same signals, both referred to as the second sampling signals; similarly, when the disconnection detection switch S3 is in the open state, as shown in the example... Figure 11 In the embodiment shown, the sampling signal obtained by the second sampling port ADC2 of the control circuit 301A can be compared with that obtained by... Figure 8 In the embodiment shown, the sampling signals obtained by the first sampling port ADC1 of the control circuit 301A are the same signals, both referred to as the first sampling signal.

[0207] It is understood that in this embodiment, by adding a third detection branch, dual disconnection detection between the ground wire of the electrical device and the ground wire of the charging device can be performed using the sampling signals at the third sampling port of the control circuit, the sampling signals at the second sampling port of the control circuit, and the closed and open states of the disconnection detection switch. Furthermore, by adding a second sampling port and acquiring a first voltage, and combining the bias voltage and the first voltage for comprehensive judgment, the reliability and accuracy of disconnection detection are further improved. Compared to a scheme using only a single bias voltage, multi-signal collaborative analysis enhances diagnostic capabilities and reduces the false positive rate. Additionally, if the scheme of comprehensively judging based on the bias voltage and the first voltage has problems, it can be switched to a scheme that uses the sampling signals at the third sampling port of the control circuit, the sampling signals at the second sampling port of the control circuit, and the closed and open states of the disconnection detection switch to determine whether a disconnection exists. This redundancy improves the resilience and fault tolerance of the disconnection detection circuit.

[0208] In another embodiment of this application, a charging system is also provided, including a charging device 20 and an electrical device 30, wherein the electrical device 30 and the charging device 20 are connected, and the electrical device 30 includes any of the disconnection detection circuits 301 described in the foregoing embodiments.

[0209] For example, the electrical device 30 and the charging device are connected via a first connection confirmation terminal CC1 and a second connection confirmation terminal CC2.

[0210] For a detailed description of the "disconnection detection circuit 301", please refer to the relevant descriptions in the foregoing embodiments, which will not be repeated here.

[0211] In an optional embodiment, the charging system may further include a charger 10. The charger 10 is a non-vehicle-mounted charger.

[0212] The following examples illustrate possible implementation schemes of the lane-changing control method described in one or more of the above embodiments.

[0213] Based on research findings, the current problems are as follows: The latest national standard for DC charging of electric vehicles has been released (GB / T18487.5-2024), which defines that vehicles need to support PE open circuit detection; This embodiment introduces how to implement PE open circuit detection in the application of Battery Management System (BMS) hardware products, while meeting the requirements of the national standard.

[0214] In one possible implementation, a negative voltage sampling circuit (i.e., bias circuit 301B) is added to the detection circuit of the second connection confirmation terminal CC2 in the BMS for detection and judgment; thereby achieving PE open circuit detection in DC charging applications of vehicles while meeting the general national standard requirements.

[0215] In one possible implementation, by adjusting the control logic and sampling voltage of the existing BMS for the sampling circuit switch of the second connection confirmation terminal CC2, and combining it with the sampling voltage of the first connection confirmation terminal CC1, it can be determined whether there is a PE open circuit fault in the DC charging system. This can meet the general national standard requirements and achieve PE open circuit detection in DC charging applications of vehicles without adding an additional negative pressure detection circuit (adapting to existing hardware circuits).

[0216] like Figure 1 As shown here, the principle of the DC charging control guidance circuit in GB / T18487.5-2024 is provided. Specifically, it can be the detection circuit of CC1 and CC2 related to BMS hardware products. When there is an open circuit in the PE connection line between the vehicle interface and the electric vehicle, how does the BMS diagnose the problem by sampling the voltage of CC2 and CC1?

[0217] like Figure 2 As shown, a simplified schematic diagram of the principle of the national standard DC charging control and guidance circuit is provided. If a PE circuit break occurs, since the circuit break detection switch S3 is open during the charging process, CC2 = PE potential (i.e., U1). - ), GND=U1 + Therefore, at this time CC2-GND=-U1=-12V (the standard-defined rated value of U1).

[0218] like Figure 3As shown, this is the currently common CC2 sampling scheme. The voltage signal of CC2 (detection point 1) is filtered by the second filter circuit 301D and then directly fed to the control circuit 301A for sampling. Under normal charging conditions, the voltage CC2-GND of detection point 1 is positive. The resistance value of the first resistor R1 can be deduced by sampling through the control circuit 301A. When a PE open circuit occurs, the voltage CC2-GND of detection point 1 is -12V. This circuit cannot perform negative voltage sampling, and the sampled value remains 0, making it impossible to accurately diagnose whether a PE open circuit exists.

[0219] The solution of this embodiment is described below.

[0220] Option 1: As Figure 6 As shown, a bias circuit 301B is added. Through this circuit, the negative voltage signal of detection point 1 can be converted into a positive voltage input to the first sampling port ADC1 of the control circuit 301A for sampling and calculation. By adding the bias circuit, this scheme can not only sample the normal CC2-GND positive voltage signal in normal charging applications, but also sample the CC2-GND negative voltage signal when PE is open-circuited, thereby diagnosing PE open-circuit faults.

[0221] However, since the positive and negative voltages at detection point 1 use the same sampling circuit (i.e., bias circuit 301B), its main limitation lies in the need to balance the sampling range of the positive and negative voltages. Specifically, if high sampling accuracy (i.e., high distinguishability) is required for the positive voltage of CC2-GND under normal conditions, then in current applications, the first resistor R1 has two types of resistance values: one is the charging gun resistance (e.g., 1kΩ), and the other is the discharging gun resistance (e.g., 2kΩ). If the distinguishability is low, after considering the overall system sampling accuracy, there may be situations where the sampled values ​​cannot accurately represent these two types of resistance values. Therefore, the sampling range of the negative voltage will be limited (unable to completely sample U1). - Voltage).

[0222] The values ​​of the first bias resistor R7 and the second bias resistor R8 are related to the sampling accuracy and sampling range of the first resistor R1. For example, if the first resistor R1 is the resistance of the charging gun (e.g., 1kΩ), then the first bias resistor R7 is in the kiloohm range and the second bias resistor R8 is in the hundred ohm range.

[0223] Option 2: As Figure 7 As shown, based on scheme 1, a positive pressure sampling input detection channel 2 is added (i.e., the second connection confirmation terminal CC2 is also connected to the second sampling port ADC2 of the control circuit 301A). When the PE is open-circuited, the negative pressure signal of CC2-GND can be sampled through ADC1, thereby diagnosing the PE open-circuit fault; under normal conditions, the positive pressure signal of CC2-GND can be sampled through ADC2, thereby diagnosing that no PE open-circuit fault has occurred.

[0224] Since the positive and negative voltages of CC2-GND use their own independent sampling channels, by configuring the resistance ratios related to each channel (i.e., when sampling negative voltage, configure the resistance values ​​of the first bias resistor R7 and the second bias resistor R8; when sampling positive voltage, configure the resistance value of the first pull-up resistor R5), we can not only ensure that the positive voltage of CC2-GND has a high sampling accuracy under normal conditions (this refers to high discrimination; in our current application, the first resistor R1 has two types of resistance values, one is the charging gun resistance value, and the other is the discharging gun resistance value. If the discrimination is low, after considering the sampling accuracy of the entire system, there may be situations where the sampled value cannot be accurately obtained for these two types of resistance values), but also ensure that the sampling range of the negative voltage of CC2-GND will be limited when PE is disconnected.

[0225] Option 3: such as Figure 8 As shown, the voltage signal of the second connection confirmation terminal CC2 (i.e., detection point 1) is directly fed to the control circuit 301A for sampling after being filtered by the first filter circuit 301C. Under normal charging conditions, the voltage CC2-GND of detection point 1 is positive. The resistance value of the first resistor R1 can be deduced by sampling through the control circuit 301A. When the PE circuit is open, CC2-GND is -12V. The circuit cannot perform negative voltage sampling, and the sampling value remains at 0. It is impossible to accurately diagnose whether there is a PE circuit. The possible causes are a PE circuit open or an open circuit of the charging switch S between the charging device 20 and the electrical equipment 30.

[0226] At this point, the specific cause can be further determined by controlling the closed switch of the open circuit detection switch S3 and sampling the values ​​of the first connection confirmation terminal CC1 (i.e., detection point 2) and the second connection confirmation terminal CC2 (i.e., detection point 1). The state relationship is shown in Table 1 below. This scheme determines whether there is a PE open circuit fault by changing the switching state of the open circuit detection switch S3 as defined by the national standard and combining the voltages of the first connection confirmation terminal CC1 (i.e., detection point 2) and the second connection confirmation terminal CC2 (i.e., detection point 1) before and after the switch state of S3 is switched (since no additional bias circuit 301B is required, the actual voltage at detection point 1 cannot be calculated).

[0227] Table 1 Fault Type Reference Table

[0228] .

[0229] In Table 1, “0” indicates an invalid or floating sample value, which is a low-level signal, and “1” indicates a valid sample value, which is a high-level signal.

[0230] The following is combined Figure 8 A brief explanation of Table 1 follows.

[0231] During normal charging, the disconnection detection switch S3 is in the open state, and the voltage can be normally collected at detection point 2. Therefore, the signal transmitted from detection point 2 obtained at the third sampling port ADC3 of control circuit 301A is "1".

[0232] When a fault occurs, the open circuit detection switch S3 is in the open state, and no voltage can be collected at detection point 2. Therefore, the signal transmitted from detection point 2 obtained by the third sampling port ADC3 of the control circuit 301A is "0". At this time, the voltage at detection point 1 is collected. If the signal transmitted from detection point 1 obtained by the first sampling port ADC1 of the control circuit 301A is also "0", then it is impossible to distinguish whether it is a PE open circuit or a charging switch S open circuit.

[0233] When the control circuit disconnection detection switch S3 is closed, the voltage at detection points 1 and 2 is sampled again. If, at this time, no voltage is sampled at detection point 2, and the signal transmitted from detection point 2 to the third sampling port ADC3 of control circuit 301A is still "0", and no voltage is sampled at detection point 1, and the signal transmitted from detection point 1 to the first sampling port ADC1 of control circuit 301A is still "0", then the fault is determined to be caused by a PE open circuit. If, at this time, no voltage is sampled at detection point 2, and the signal transmitted from detection point 2 to the third sampling port ADC3 of control circuit 301A is still "0", and voltage is sampled at detection point 1, and the signal transmitted from detection point 1 to the first sampling port ADC1 of control circuit 301A is "1", then the fault is determined to be caused by an open circuit in charging switch S.

[0234] It should be noted that although the steps of the method in this application are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps; or steps from different embodiments may be combined into a new technical solution.

[0235] The descriptions of the above device embodiments are similar to those of the above method embodiments, and have similar beneficial effects. For technical details not disclosed in the device embodiments of this application, please refer to the descriptions of the method embodiments of this application for understanding.

[0236] It should be noted that the module division in the embodiments of this application is illustrative and only represents one logical functional division. In actual implementation, there may be other division methods. Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, exist as separate physical units, or have two or more units integrated into one unit. The integrated units can be implemented in hardware, as software functional units, or a combination of software and hardware.

[0237] It should be understood that the phrases "one embodiment," "an embodiment," or "some embodiments" mentioned throughout the specification mean that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment," "in one embodiment," or "in some embodiments" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. It should be understood that in the various embodiments of this application, the sequence numbers of the above-described processes do not imply a sequential order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application. The sequence numbers of the above-described embodiments are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. The descriptions of the various embodiments above tend to emphasize the differences between the various embodiments; their similarities or commonalities can be referred to mutually, and for the sake of brevity, they will not be repeated here.

[0238] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three kinds of relationships. For example, object A and / or object B can represent three situations: object A exists alone, object A and object B exist simultaneously, and object B exists alone.

[0239] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0240] In the several embodiments provided in this application, it should be understood that the disclosed circuits and methods can be implemented in other ways. The embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods, such as: multiple modules or components can be combined, or integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the various components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, and can be electrical, mechanical, or other forms.

[0241] The modules described above as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules. They may be located in one place or distributed across multiple network units. Some or all of the modules may be selected to achieve the purpose of this embodiment according to actual needs.

[0242] In addition, each functional module in the various embodiments of this application can be integrated into one processing unit, or each module can be a separate unit, or two or more modules can be integrated into one unit; the integrated modules can be implemented in hardware or in the form of hardware plus software functional units.

[0243] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as mobile storage devices, read-only memory (ROM), magnetic disks, or optical disks.

[0244] The features disclosed in the several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0245] The features disclosed in the several embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0246] The above description is merely an embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A wire breakage detection circuit, characterized in that, Applied to electrical equipment, the open circuit detection circuit includes a power supply circuit, a first detection branch, a bias circuit, and a control circuit, wherein: The power supply circuit is used to provide power to the first resistor in the charging device; The first detection branch is connected between the first detection point and the first sampling port of the control circuit, and is used to detect the first voltage at the first detection point; wherein, the power supply circuit includes a disconnection detection switch and a first power supply, the first power supply and the disconnection detection switch are connected in series, and the first detection point is set between the disconnection detection switch and the first resistor; The bias circuit is disposed on the first detection branch and is used to bias the first voltage at the first detection point and provide a bias voltage to the first sampling port of the control circuit. The control circuit is used to control the power supply circuit to be in an open state when the electrical device is being charged by the charging device, and to detect the disconnection between the ground wire of the electrical device and the ground wire of the charging device based on the bias voltage obtained from the first sampling port.

2. The open circuit detection circuit according to claim 1, characterized in that, The control circuit is further configured to determine, when the amplitude of the bias voltage is within a first preset range, that there is no open circuit fault between the ground wire of the electrical device and the ground wire of the charging device; and to determine, when the amplitude of the bias voltage is within a second preset range, that there is an open circuit fault between the ground wire of the electrical device and the ground wire of the charging device. Wherein, the lower limit of the first preset range is higher than the upper limit of the second preset range.

3. The open circuit detection circuit according to claim 1, characterized in that, The control circuit is also used to control the disconnection detection switch to open when the electrical equipment is being charged by the charging device, so that the power supply circuit is in a disconnected state.

4. The open circuit detection circuit according to claim 3, characterized in that, The bias circuit includes a first bias branch and a second bias branch, wherein: The second bias branch is set on the first detection branch; The first bias branch is connected between the power supply circuit and the first bias branch.

5. The open circuit detection circuit according to claim 4, characterized in that, The first bias branch includes a first bias resistor, and the second bias branch includes a second bias resistor, wherein: The first terminal of the first bias resistor is connected to the positive terminal of the first power supply. The first end of the second bias resistor is connected to the first detection point; The second end of the first bias resistor is connected to the second end of the second bias resistor and the first sampling port, respectively.

6. The open circuit detection circuit according to claim 1, characterized in that, The disconnection detection circuit further includes a first filtering circuit, which is disposed between the bias circuit and the first sampling port; wherein: The first filtering circuit is used to perform voltage regulation and filtering on the bias voltage so that the first sampling port obtains a bias voltage that satisfies the first condition.

7. The open circuit detection circuit according to claim 3, characterized in that, The power supply circuit also includes a first pull-up resistor, wherein: The first pull-up resistor is connected in series on the connection line between the first power supply and the disconnection detection switch.

8. The open circuit detection circuit according to any one of claims 1 to 7, characterized in that, The wire breakage detection circuit further includes a second detection branch, wherein: The second detection branch is connected between the first detection point and the second sampling port of the control circuit, and is used to detect the first voltage at the first detection point; The control circuit is used to control the power supply circuit to be in an open state when the electrical device is being charged by the charging device, and to detect the disconnection between the ground wire of the electrical device and the ground wire of the charging device based on the first voltage obtained by the second sampling port and the bias voltage obtained by the first sampling port.

9. The open circuit detection circuit according to claim 8, characterized in that, The control circuit is further configured to determine that there is no open circuit fault between the ground wire of the electrical equipment and the ground wire of the charging device when the amplitude of the first voltage is within a third preset range and the amplitude of the bias voltage is outside a second preset range. And when the amplitude of the bias voltage is within a second preset range and the amplitude of the first voltage is outside a third preset range, it is determined that there is a disconnection fault between the ground wire of the electrical equipment and the ground wire of the charging device.

10. The open circuit detection circuit according to claim 8, characterized in that, The disconnection detection circuit further includes a second filtering circuit, which is disposed on the second detection branch; wherein: The second filtering circuit is used to perform voltage regulation and filtering on the first voltage at the first detection point so that the second sampling port obtains a first voltage that satisfies the second condition.

11. A method for detecting broken wires, characterized in that, A disconnection detection circuit for use in electrical equipment, the disconnection detection circuit includes a power supply circuit, a first detection branch, a bias circuit and a control circuit, the power supply circuit is used to provide power to a first resistor in a charging device; The first detection branch is connected between the first detection point and the first sampling port of the control circuit. The power supply circuit includes a disconnection detection switch and a first power supply. The first power supply and the disconnection detection switch are connected in series. The first detection point is located between the disconnection detection switch and the first resistor. The bias circuit is disposed on the first detection branch; When the electrical device is being charged via a charging device, the disconnection detection method includes: The control circuit controls the power supply circuit to be in an open state, and obtains the bias voltage provided by the bias circuit through the first sampling port; Based on the bias voltage, a disconnection detection is performed between the ground wire of the electrical equipment and the ground wire of the charging device.

12. The wire breakage detection method according to claim 11, characterized in that, When the disconnection detection circuit further includes a second detection branch, the second detection branch is connected between the first detection point and the second sampling port of the control circuit; the disconnection detection method further includes: The control circuit controls the power supply circuit to be in a disconnected state, and obtains the first voltage at the first detection point through the second sampling port; Based on the bias voltage and the first voltage, a disconnection detection is performed between the ground wire of the electrical equipment and the ground wire of the charging device.

13. The wire breakage detection method according to claim 12, characterized in that, When the disconnection detection circuit further includes a third detection branch, the third detection branch is connected between the second detection point and the third sampling port of the control circuit; the disconnection detection method further includes: The control circuit controls the power supply circuit to be in a disconnected state, and obtains a first sampling signal through the second sampling port and a third sampling signal through the third sampling port; The control circuit controls the power supply circuit to be in a connected state, and obtains a second sampling signal through the second sampling port and a fourth sampling signal through the third sampling port; Based on the first sampling signal, the third sampling signal, the second sampling signal, and the fourth sampling signal, a disconnection detection is performed between the ground wire of the electrical equipment and the ground wire of the charging device.

14. The wire breakage detection method according to claim 13, characterized in that, The step of detecting a break in the connection between the ground wire of the electrical device and the ground wire of the charging device based on the first sampling signal, the third sampling signal, the second sampling signal, and the fourth sampling signal includes: When the first sampling signal, the third sampling signal, the second sampling signal and the fourth sampling signal are all in the first level state, it is determined that there is a disconnection fault between the ground wire of the electrical equipment and the ground wire of the charging device. When the first sampling signal, the third sampling signal, and the fourth sampling signal are all at the first level, and the second sampling signal is at the second level, it is determined that the charging switch between the electrical equipment and the charging device is disconnected.

15. A charging system, characterized in that, The charging system includes a charging device and an electrical device, wherein the electrical device and the charging device are connected, and the electrical device includes a disconnection detection circuit as described in any one of claims 1-10.

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