Grounding detection device and method, charging device, storage medium and computer equipment

Abstract

The invention discloses a grounding detection device and method, a charging device, a storage medium and computer equipment, and relates to the technical field of charging control. The grounding detection device comprises a control module, a voltage dividing module and a differential voltage sampling module, wherein the voltage dividing module comprises a switch unit. When the switch unit is switched off, the voltage division module outputs a first sampling voltage after the first phase line or the neutral line is subjected to voltage division, when the switch unit is switched on, the voltage division module outputs a second sampling voltage after the first phase line or the neutral line and the protective ground line are subjected to voltage division, and the switch unit is switched on or switched off based on a grounding detection signal output by the control module; the differential voltage sampling module performs differential sampling on the first sampling voltage when the switch unit is switched off, and performs differential sampling on the second sampling voltage when the switch unit is switched on; the control module determines a grounding detection result based on the differential sampling result of the first sampling voltage and the differential sampling result of the second sampling voltage. The device can improve the accuracy of grounding detection.

Description

Technical Field

[0001] The present application relates to the field of charging control technology, and in particular to a grounding detection device, method, charging device, storage medium and computer equipment. Background Art

[0002] In the electrical system of the charging device, the grounding system is an indispensable part. The main function of the grounding system is to guide the current to the ground in the event of a fault, thereby protecting personal safety and preventing accidents such as electrical fires. At present, the grounding system mainly measures the voltage between the protective ground wire and the neutral wire inside the charging device to calculate the resistance of the grounding resistor, and then judges whether the grounding state is good by the resistance of the grounding resistor. Generally speaking, if the resistance of the grounding resistor exceeds the preset range, it is considered that the grounding is poor.

[0003] However, in some cases, the method of performing grounding detection by inferring the grounding resistance through the grounding voltage is not accurate. For example, when the neutral line is far away or the current on the neutral line is large, the internal resistance of the neutral line itself may introduce additional voltage drop, resulting in inaccurate measured grounding voltage, which may lead to misjudgment of grounding detection when the grounding is good. In addition, when the three-phase system is load balanced, the current flowing through the neutral line can be very small or zero. At this time, even if the grounding is not good, the grounding voltage cannot be effectively detected, and the true grounding state cannot be determined. Moreover, in a split-phase power system, the charging device is not connected to the neutral line, making the detection method based on the voltage between the neutral line and the protective ground line impossible to apply. The above-mentioned various conditions are the shortcomings of the existing grounding detection schemes. Summary of the invention

[0004] In view of this, the embodiments of the present application provide a grounding detection device, method, charging device, storage medium and computer equipment, the main purpose of which is to solve the technical problems of inaccurate grounding detection and insufficient application scenarios.

[0005] According to one aspect of the present application, a ground detection device is provided, the device comprising a control module, a voltage dividing module and a differential voltage sampling module, the voltage dividing module comprising a switch unit, wherein:

[0006] The output end of the control module is connected to the control end of the switch unit, and is used to respond to the ground detection instruction and output a ground detection signal;

[0007] The first input end of the voltage divider module is connected to the first phase line or the neutral line, and the second input end is connected to the protective ground line through the switch unit; when the switch unit is disconnected, the voltage divider module outputs a first sampled voltage after the first phase line or the neutral line is divided, and when the switch unit is turned on, the voltage divider module outputs a second sampled voltage after the first phase line or the neutral line and the protective ground line are divided, wherein the switch unit is turned on or off based on the ground detection signal;

[0008] The first input end of the differential voltage sampling module is connected to the output end of the voltage dividing module, and the second input end is connected to the second phase line or the neutral line, and is used to perform differential sampling on the first sampling voltage when the switch unit is disconnected, and perform differential sampling on the second sampling voltage when the switch unit is turned on;

[0009] The input end of the control module is connected to the output end of the differential voltage sampling module, and is used to determine a ground detection result based on a differential sampling result of the first sampling voltage and a differential sampling result of the second sampling voltage.

[0010] Optionally, the voltage-dividing module also includes a first voltage-dividing branch composed of at least one voltage-dividing resistor, wherein the first end of the first voltage-dividing branch is connected to the first phase line as the first input end of the voltage-dividing module, and the second end of the first voltage-dividing branch is connected to the first input end of the differential voltage sampling module as the output end of the voltage-dividing module; when the switch unit is turned on, the voltage-dividing module also includes a second voltage-dividing branch composed of a grounding resistor; the first end of the second voltage-dividing branch is connected to the protective ground line as the second input end of the voltage-dividing module, the second end of the second voltage-dividing branch is connected to the controlled first end of the switch unit, and the controlled second end of the switch unit is connected to the first input end of the differential voltage sampling module as the output end of the voltage-dividing module.

[0011] Optionally, the first input end of the voltage divider module is connected to the first phase line; the voltage divider module is used to output the sampled voltage of the first phase line after voltage division as the first sampling voltage when the switch unit is disconnected, and to output the sampled voltage of the first phase line and the protective ground line after voltage division as the second sampling voltage when the switch unit is turned on.

[0012] Optionally, the voltage-dividing module further includes a first voltage-dividing branch composed of at least one voltage-dividing resistor, and a third voltage-dividing branch composed of at least one voltage-dividing resistor, wherein the first end of the first voltage-dividing branch is connected to the first phase line or the neutral line as the first input end of the voltage-dividing module, and the second end of the first voltage-dividing branch is connected to the first input end of the differential voltage sampling module as the output end of the voltage-dividing module; the first end of the third voltage-dividing branch is connected to the second phase line or the neutral line as the third input end of the voltage-dividing module, and the second end of the third voltage-dividing branch is connected to the first input end of the differential voltage sampling module as the output end of the voltage-dividing module; when the switch unit is turned on, the voltage-dividing module further includes a second voltage-dividing branch composed of a grounding resistor; the first end of the second voltage-dividing branch is connected to the protective ground line as the second input end of the voltage-dividing module, the second end of the second voltage-dividing branch is connected to the controlled first end of the switch unit, and the controlled second end of the switch unit is connected to the first input end of the differential voltage sampling module as the output end of the voltage-dividing module.

[0013] Optionally, the first input terminal of the voltage divider module is connected to the first phase line, and the third input terminal is connected to the second phase line; the voltage divider module is used to output the sampled voltage of the first phase line and the second phase line as the first sampled voltage when the switch unit is disconnected, and to output the sampled voltage of the first phase line, the second phase line and the protective ground line as the second sampled voltage when the switch unit is turned on; or, the first input terminal of the voltage divider module is connected to the first phase line, and the third input terminal is connected to the neutral line; the voltage divider module is used to output the sampled voltage of the first phase line and the neutral line when the switch unit is disconnected. The voltage-dividing module is used to output a sampled voltage of the neutral line as a first sampled voltage, and when the switch unit is turned on, output a sampled voltage of the first phase line, the neutral line and the protective ground line as a second sampled voltage; or, a first input end of the voltage-dividing module is connected to the neutral line, and a third input end is connected to the second phase line; the voltage-dividing module is used to output a sampled voltage of the neutral line and the second phase line as a first sampled voltage when the switch unit is disconnected, and output a sampled voltage of the neutral line, the second phase line and the protective ground line as a second sampled voltage when the switch unit is turned on.

[0014] Optionally, the differential voltage sampling module includes a differential amplification unit composed of an operational amplifier and a resistor, wherein the positive input terminal of the differential amplification unit is connected to the output terminal of the voltage divider module as the first input terminal of the differential voltage sampling module, and the positive input terminal of the differential amplification unit is also connected to a constant voltage source through a sampling resistor; the negative input terminal of the differential amplification unit is connected to the second phase line or the neutral line as the second input terminal of the differential voltage sampling module; and the output terminal of the differential amplification unit is connected to the input terminal of the control module.

[0015] Optionally, the negative input terminal of the differential amplifier unit is connected to the second phase line as the second input terminal of the differential voltage sampling module; the differential amplifier unit is used to receive a first differential sampling voltage between the first sampling voltage and the sampling voltage of the second phase line as the differential sampling result of the first sampling voltage when the switch unit is disconnected, and receive a second differential sampling voltage between the second sampling voltage and the sampling voltage of the second phase line as the differential sampling result of the second sampling voltage when the switch unit is turned on; or, the negative input terminal of the differential amplifier unit is connected to the neutral line as the second input terminal of the differential voltage sampling module; the differential amplifier unit is used to receive a first differential sampling voltage between the first sampling voltage and the sampling voltage of the neutral line as the differential sampling result of the first sampling voltage when the switch unit is disconnected, and receive a second differential sampling voltage between the second sampling voltage and the sampling voltage of the neutral line as the differential sampling result of the second sampling voltage when the switch unit is turned on.

[0016] Optionally, the differential voltage sampling module also includes a first voltage dividing unit and a second voltage dividing unit, wherein the first voltage dividing unit is connected between the output end of the voltage dividing module and the positive input end of the differential amplifier unit; the second voltage dividing unit is connected between the second phase line and the negative input end of the differential amplifier unit, or the second voltage dividing unit is connected between the neutral line and the negative input end of the differential amplifier unit.

[0017] Optionally, the differential voltage sampling module also includes a first filtering unit and / or a first protection unit, wherein the first filtering unit is arranged between the negative input terminal of the differential amplifier unit and the output terminal of the differential amplifier unit, and / or the first filtering unit is arranged between the input terminal and the ground terminal of the control module, and / or the first filtering unit is arranged between the output terminal of the differential amplifier unit and the input terminal of the control module; and / or the first protection unit is arranged between the output terminal and the power supply terminal of the differential amplifier unit, and between the output terminal and the ground terminal of the differential amplifier unit.

[0018] Optionally, the switch unit includes a switch tube and a switch isolation device, wherein the control end of the switch tube is connected to the output end of the control module as the control end of the switch unit, and the control end of the switch tube is also connected to the output end of the control module through a voltage-dividing resistor, and is connected to the ground end through a voltage-dividing resistor; the first end of the switch tube is connected to the ground end, the second end of the switch tube is connected to the negative input end of the switch isolation device, and the positive input end of the switch isolation device is connected to the power supply end; the first output end of the switch isolation device is connected to the protective ground wire as the controlled first end of the switch unit, and the second output end of the switch isolation device is connected to the first input end of the differential voltage sampling module as the controlled second end of the switch unit.

[0019] Optionally, the switch unit also includes a second filtering unit and / or a second protection unit, wherein the second filtering unit is arranged between the control end and the ground end of the switch tube; and / or the second protection unit is arranged between the first output end of the switch isolation device and the second output end of the switch isolation device.

[0020] According to another aspect of the present application, a grounding detection method is provided. The method is applied to the grounding detection device described in any one of the above embodiments, and the method includes:

[0021] In response to the grounding detection instruction, a first grounding detection signal is output to disconnect the connection between the protective ground line and the voltage dividing module, and a first differential sampling voltage between the first sampling voltage and a preset reference voltage is received, wherein the reference voltage is a sampling voltage of the second phase line or the neutral line;

[0022] Output a second ground detection signal to connect the protection ground line to the voltage dividing module, and receive a second differential sampling voltage between the second sampling voltage and the reference voltage;

[0023] A ground detection result is determined based on a difference between the first differential sampling voltage and the second differential sampling voltage.

[0024] Optionally, the receiving of a first differential sampling voltage between a first sampling voltage and a preset reference voltage includes: receiving a first differential sampling voltage between the first sampling voltage and a sampling voltage of a second phase line, wherein the first sampling voltage is a sampling voltage after the first phase line is divided, or is a sampling voltage after the first phase line and the second phase line are divided; the receiving of a second differential sampling voltage between the second sampling voltage and the reference voltage includes: receiving a second differential sampling voltage between the second sampling voltage and the sampling voltage of the second phase line, wherein the second sampling voltage is a sampling voltage after the first phase line and a protective ground line are divided, or is a sampling voltage after the first phase line, the second phase line and the protective ground line are divided.

[0025] Optionally, receiving a first differential sampling voltage between a first sampling voltage and a preset reference voltage includes: receiving a first differential sampling voltage between the first sampling voltage and a sampling voltage of a neutral line, wherein the first sampling voltage is a sampling voltage after the first phase line is divided, or is a sampling voltage after the first phase line and the neutral line are divided; receiving a second differential sampling voltage between a second sampling voltage and the reference voltage includes: receiving a second differential sampling voltage between the second sampling voltage and a sampling voltage of a neutral line, wherein the second sampling voltage is a sampling voltage after the first phase line and the protective ground line are divided, or is a sampling voltage after the first phase line, the neutral line and the protective ground line are divided.

[0026] Optionally, receiving a first differential sampling voltage between a first sampling voltage and a preset reference voltage includes: receiving a first differential sampling voltage between the first sampling voltage and a sampling voltage of a second phase line, wherein the first sampling voltage is a sampling voltage after a neutral line and a second phase line are divided; receiving a second differential sampling voltage between a second sampling voltage and the reference voltage includes: receiving a second differential sampling voltage between the second sampling voltage and a sampling voltage of the second phase line, wherein the second sampling voltage is a sampling voltage after a neutral line, a second phase line and a protective ground line are divided.

[0027] Optionally, determining the grounding detection result based on the difference between the first differential sampling voltage and the second differential sampling voltage includes: generating a poor grounding detection result when the duration for which the difference between the first differential sampling voltage and the second differential sampling voltage is greater than a preset voltage threshold exceeds a preset duration.

[0028] Optionally, after generating the detection result of poor grounding, the method further includes: outputting a poor grounding alarm signal, and / or outputting a switch control signal for controlling the power switch to disconnect, so as to stop charging.

[0029] Optionally, the method further includes: in a charging state, periodically generating a ground detection instruction, and performing a ground detection in response to the ground detection instruction periodically.

[0030] According to another aspect of the present application, a charging device is provided, wherein the grounding detection device described in any one of the above embodiments is disposed inside the charging device.

[0031] According to another aspect of the present application, a storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the above-mentioned ground detection method is implemented.

[0032] According to another aspect of the present application, a computer device is provided, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor implements the above-mentioned ground detection method when executing the program.

[0033] By means of the above technical solution, the embodiments of the present application provide a grounding detection device, method, charging device, storage medium and computer equipment, including a control module, a voltage dividing module and a differential voltage sampling module, wherein the voltage dividing module includes a switch unit. When the switch unit is disconnected, the voltage dividing module outputs a first sampling voltage after the first phase line or the neutral line is divided; when the switch unit is turned on, the voltage dividing module outputs a second sampling voltage after the first phase line or the neutral line and the protective ground line are divided, wherein the switch unit is turned on or off based on the grounding detection signal output by the control module; the differential voltage sampling module performs differential sampling on the first sampling voltage when the switch unit is disconnected, and performs differential sampling on the second sampling voltage when the switch unit is turned on; the control module determines the grounding detection result based on the differential sampling result of the first sampling voltage and the differential sampling result of the second sampling voltage. The above device obtains the grounding resistance through the voltage of the measured point on the phase line or also including the neutral line, and the voltage difference after the voltage of the measured point on the phase line or also including the neutral line is divided by the ground. The difference between the two measurements is only whether it is grounded. Therefore, it can effectively avoid the influence of whether the grid state is balanced, the voltage drop caused by the impedance on the transmission cable, and the internal parameters of the charging device on the grounding detection result, thereby effectively improving the accuracy of grounding detection and the accuracy of detection under different grid states. In addition, when performing grounding detection, the above device does not need to be connected to the neutral line, but can choose to connect to the first phase line and the second phase line. Therefore, the above grounding detection device can be applied to a variety of power systems, such as TN system, TT system and split-phase transformer system, thereby improving the versatility and practicality of the grounding detection device, solving the problem of difficult and inaccurate grounding detection of the charging device, and providing a strong guarantee for the safe use of the charging device.

[0034] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0036] Figure 1A schematic structural diagram of a grounding detection device provided in the prior art is shown;

[0037] Figure 2 A schematic structural diagram of a grounding detection device provided in the prior art is shown;

[0038] Figure 3 A schematic diagram of the structure of a ground detection device provided in an embodiment of the present application is shown;

[0039] Figure 4 A schematic diagram of the structure of a ground detection device provided in an embodiment of the present application is shown;

[0040] Figure 5 A schematic diagram of the structure of a ground detection device provided in an embodiment of the present application is shown;

[0041] Figure 6 A schematic diagram of the structure of a ground detection device provided in an embodiment of the present application is shown;

[0042] Figure 7 A schematic diagram of the structure of a ground detection device provided in an embodiment of the present application is shown;

[0043] Figure 8 A circuit connection diagram of a ground detection device provided in an embodiment of the present application is shown;

[0044] Fig. 9 A schematic flow chart of a grounding detection method provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0045] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0046] At present, charging devices are usually installed in outdoor environments. Due to various unforeseen factors, such as the movement of the charging device, natural aging, improper construction, etc., the grounding continuity of the charging device may be problematic. For example, the grounding wire of a mobile charging device may become loose during transportation or installation; the grounding screws of a fixed charging device may rust due to long-term exposure to the outdoors, thus affecting the grounding continuity; and during the construction process, the grounding wire may also break. These factors will reduce the reliability of the grounding system and increase the risk of electric shock to users.

[0047] In order to solve the grounding continuity problem caused by the above-mentioned factors, existing charging devices are usually designed with a grounding detection function. The grounding detection function can immediately stop charging and issue a warning to the user when a grounding fault is detected, thereby preventing electric shock accidents caused by poor grounding. Figure 1 As shown, the prior art proposes a grounding detection scheme in a TN power grid system, in which the neutral line N is connected to the protective grounding line PE at the transformer end, and the resistance between the charging device and the PE line is recorded as Rground. The charging device contains capacitors C1 to C4 (these capacitors are usually called Y capacitors). At this time, an induced voltage will be generated on the PE line (hereinafter referred to as C_PE) inside the charging device terminal. Theoretically, since the N line and the PE line are connected through the transformer end, the voltage difference between the N line and the C_PE line is the voltage drop on Rground. Based on this, the Rground value can be calculated by measuring the voltage Uground between the N line and the C_PE line, thereby evaluating the grounding condition.

[0048] However, the actual situation is usually much more complicated than the theoretical model. Figure 2 As shown in the figure, there is actually some impedance on the N line, which can be represented by resistors RN1 and RN2. These resistors will interfere with the measurement accuracy of Uground. Especially when the N line is long, even if the grounding is good, the measured Uground is relatively large, which is mainly caused by the voltage drop on resistors RN1 and RN2. At this time, if there is a large current flowing on the N line, even if the grounding is good, it may cause misjudgment.

[0049] On the other hand, refer to Figure 1 In a three-phase power supply system, Uground can only be detected when the system is in a certain degree of imbalance, that is, when current flows through capacitor C4. If the loads of L1, L2, and L3 are all heavy, so that the system reaches a balanced state, even if Rground is disconnected, Uground may be close to zero, resulting in the inability to correctly identify whether the ground wire is disconnected. For example, when the charging device is in an idle state, the auxiliary source of the same line L1 and N supplies power to the charging device, which is reflected in L2 and L3. There is no current, only L1 and N have current, so an imbalance occurs. At this time, the induced voltage can reach hundreds of volts. When the charging device is charging, the charging current is tens of amperes, and the auxiliary source current is in the milliampere level. In comparison, the milliampere current of the auxiliary source is too small, and the imbalance is reduced. Therefore, the induced voltage at this time becomes smaller, only a few volts, and even if Rground is disconnected, it cannot be identified. In addition, for the scenario of using a split-phase transformer (compliant with UL standards), the charging device is only connected to L1, L2 and PE lines, and is not connected to the neutral line, so grounding detection cannot be performed. Similarly, in a DC charging device system, sometimes only the L1, L2, and L3 phase lines are connected. In this configuration, grounding detection cannot be achieved because there is no neutral line. In addition, the introduction of the N line will also increase the complexity and cost of cable laying.

[0050] In view of the above problems, this embodiment proposes a grounding detection device, such as Figure 3 As shown, the above-mentioned device includes a control module 10, a voltage divider module 20 and a differential voltage sampling module 30, wherein the voltage divider module 20 includes a switch unit 21. In this embodiment, the output end of the control module 10 is connected to the control end of the switch unit 21, and the control module 10 can be used to respond to the grounding detection instruction and output a grounding detection signal. The first input end of the voltage divider module 20 is connected to the first phase line or the neutral line, and the second input end is connected to the protective ground line through the switch unit 21. When the switch unit 21 is disconnected, the voltage divider module 20 outputs a first sampling voltage after the first phase line or the neutral line is divided; when the switch unit 21 is turned on, the voltage divider module 20 outputs a second sampling voltage after the first phase line or the neutral line and the protective ground line are divided, wherein the switch unit 21 is turned on or off based on the grounding detection signal output by the control module 10. Furthermore, the first input end of the differential voltage sampling module 30 is connected to the output end of the voltage divider module 20, and the second input end is connected to the second phase line or the neutral line, wherein the differential voltage sampling module 30 can be used to differentially sample the first sampling voltage when the switch unit 21 is disconnected, and to differentially sample the second sampling voltage when the switch unit 21 is turned on. Finally, the input end of the control module 10 is also connected to the output end of the differential voltage sampling module 30, and is used to determine the grounding detection result based on the differential sampling result of the first sampling voltage and the differential sampling result of the second sampling voltage. In this embodiment, the above-mentioned grounding detection device can be arranged in a charging device, wherein the charging device can be a variety of charging devices such as an AC pile, a DC pile, a charging pile, and a charging terminal derived from the charging pile.

[0051] Specifically, the above-mentioned grounding detection device will issue a grounding detection instruction when performing grounding detection, wherein the grounding detection instruction can be issued periodically or initiated by the user. Further, the control module 10 can output a grounding detection signal in response to the grounding detection instruction, and output the grounding detection signal to the switch unit 21 of the voltage divider module 20 to control the switch unit 21 to be in an on or off state. In this embodiment, the first input end of the voltage divider module 20 is connected to the first phase line or the neutral line, and the second input end is connected to the protective ground line through the switch unit 21. When the switch unit 21 is in the off state, the voltage divider module 20 will divide the voltage of the first phase line or the neutral line and output the first sampled voltage. At this time, the first input end of the differential voltage sampling module 30 will receive the first sampled voltage, and the second input end is connected to the second phase line or the neutral line. Based on this, the differential voltage sampling module 30 can perform differential sampling on the first sampled voltage and the second phase line or the neutral line, and then the differential voltage sampling module 30 can send this differential sampling result to the control module 10. Subsequently, the control module 10 controls the switch unit 21 to be turned on. At this time, the voltage divider module 20 divides the voltage between the first phase line or the neutral line and the protective ground line and outputs the second sampled voltage. Correspondingly, the differential voltage sampling module 30 performs differential sampling on the second sampled voltage and the second phase line or the neutral line and sends the differential sampling result to the control module 10. Finally, the control module 10 can perform a comprehensive analysis based on the received differential sampling result of the first sampled voltage and the differential sampling result of the second sampled voltage, for example, comparing the difference between the two differential sampling results with a preset threshold value to determine the grounding detection result, that is, to determine whether the charging device is well grounded.

[0052] In this embodiment, the voltage divider module 20 can input a voltage signal as a voltage divider branch connected to the voltage divider module, or can input two voltage signals as two voltage divider branches connected to the voltage divider module. Among them, when the voltage divider module 20 inputs a voltage signal, the voltage signal should be a phase line signal. For example, the voltage divider module can connect any one of L1, L2, and L3 to the voltage divider module for grounding detection. When the voltage divider module 20 inputs two voltage signals, the two voltage signals can be a combination signal of the phase line and the neutral line, or a combination signal of two phase lines. For example, the voltage divider module can connect any combination signal of L1 and the neutral line, L2 and the neutral line, L3 and the neutral line, L1 and L2, L1 and L3, and L2 and L3 to the voltage divider module for grounding detection. In addition, when the switch unit 21 is closed, the switch module 20 can also connect the protective ground wire to the voltage divider module 20 and serve as a voltage divider branch. Through the above method, the voltage dividing module 21 can measure the change of the phase line voltage value after the circuit is connected to the protective ground wire, so as to perform subsequent grounding detection. The above circuit connection method can enable the grounding detection device to configure the circuit connection method according to different power grid conditions, effectively improving the versatility and practicality of the device.

[0053] The above embodiment obtains the grounding resistance by comparing the voltage of the measured point on the phase line or also including the neutral line, and the voltage difference after the voltage of the measured point on the phase line or also including the neutral line is divided by the grounding voltage. The difference between the two measurements is only whether it is grounded. Therefore, it can effectively avoid the influence of whether the grid state is balanced, the voltage drop caused by the impedance on the transmission cable, and the internal parameters of the charging device on the grounding detection result, thereby effectively improving the accuracy of grounding detection and the accuracy of detection under different grid states. In addition, when performing grounding detection, the above device does not need to be connected to the neutral line, but can choose to connect to the first phase line and the second phase line. Therefore, the above grounding detection device can be applied to a variety of power systems, such as TN system, TT system and split-phase transformer system, thereby improving the versatility and practicality of the grounding detection device. In general, this solution solves the problems of difficult grounding detection, inaccurate detection, and limited applicable scenarios of charging devices, and provides a strong guarantee for the safe use of charging devices.

[0054] In one embodiment, Figure 4As shown, the voltage dividing module 20 includes a switch unit 21 and a first voltage dividing branch 22 composed of at least one voltage dividing resistor. When the switch unit 21 is turned on, the voltage dividing module 20 also includes a second voltage dividing branch 23 composed of a grounding resistor. In this embodiment, the first end of the first voltage dividing branch 22 is connected to the first phase line as the first input end of the voltage dividing module 20, and the second end of the first voltage dividing branch 22 is connected to the first input end of the differential voltage sampling module 30 as the output end of the voltage dividing module 20. Further, when the switch unit 21 is turned on, the first end of the second voltage dividing branch 23 is connected to the protective ground line as the second input end of the voltage dividing module 20, the second end of the second voltage dividing branch 23 is connected to the controlled first end of the switch unit 21, and the controlled second end of the switch unit 21 is connected to the first input end of the differential voltage sampling module 30 as the output end of the voltage dividing module 20.

[0055] Specifically, in this embodiment, the voltage-dividing module 20 includes, in addition to the switch unit 21, a first voltage-dividing branch 22 composed of at least one voltage-dividing resistor, and a second voltage-dividing branch 23 composed of a grounding resistor connected when the switch unit 21 is closed. One end of the first voltage-dividing branch 22 is directly connected to the first phase line as the input end of the voltage-dividing module 20, and the other end is connected to the input end of the differential voltage sampling module 30 as the output end, and is used to provide the differential voltage sampling module 30 with a voltage-dividing signal of the first phase line when the switch unit 21 is disconnected. Further, when the switch unit 21 is closed, the second voltage-dividing branch 23 is activated, one end of which is connected to the protective ground line, and the other end is connected to a controlled end of the switch unit 21. At the same time, the other controlled end of the switch unit 21 is connected to the differential voltage sampling module 30 as the output of the voltage-dividing module 20, and is used to output the voltage-dividing signal of the first phase line and the protective ground line to the differential voltage sampling module 30.

[0056] The above embodiment can realize flexible voltage division processing of the first phase line voltage and the protective ground line voltage by setting a switch unit, a first voltage division branch and a second voltage division branch in the voltage division module, combined with the switching function of the switch unit. The above circuit can effectively improve the accuracy of grounding detection, avoid interference of external factors on the grounding detection results, and enhance the stability and reliability of the system. In addition, the above circuit does not need to be connected to the neutral line, which effectively reduces the circuit cost. At the same time, it can be flexibly applied to various power system environments such as TN system, TT system and split-phase transformer system, and has strong versatility and flexibility.

[0057] In one embodiment, Figure 4As shown, the first input end of the voltage divider module 20 is connected to the first phase line. In this connection mode, the voltage divider module can output the divided sampled voltage of the first phase line as the first sampled voltage when the switch unit 21 is disconnected, and output the divided sampled voltage of the first phase line and the protective ground line as the second sampled voltage when the switch unit 21 is turned on.

[0058] Specifically, in the present embodiment, the first input terminal of the voltage divider module 20 is connected to the first phase line. In this connection mode, when the switch unit 21 is in the disconnected state, the voltage divider module 20 will divide the voltage of the first phase line and output the sampled voltage after voltage division, i.e., the first sampled voltage; when the switch unit 21 is turned on, the voltage divider module 20 will divide the voltage between the first phase line and the protective ground line and output the divided sampled voltage, i.e., the second sampled voltage. The above circuit connection mode enables the voltage divider module 20 to flexibly adjust its output according to the state of the switch unit 21 and provide the necessary voltage signal for the subsequent differential voltage sampling module.

[0059] The above embodiment can realize accurate voltage division sampling of the first phase line voltage and the voltage between the first phase line and the protective ground line by connecting the first input end of the voltage division module to the first phase line. The above circuit can improve the accuracy of grounding detection and avoid safety hazards caused by poor grounding. In addition, the above circuit can be applied to a variety of power system environments and has strong versatility and adaptability.

[0060] In one embodiment, Figures 5 to 7 As shown, the voltage dividing module 20 includes a switch unit 21, a first voltage dividing branch 22 composed of at least one voltage dividing resistor, and a third voltage dividing branch 24 composed of at least one voltage dividing resistor. When the switch unit 21 is turned on, the voltage dividing module 20 also includes a second voltage dividing branch 23 composed of a grounding resistor. In this embodiment, the first end of the first voltage dividing branch 22 is connected to the first phase line or the neutral line as the first input end of the voltage dividing module 20, and the second end of the first voltage dividing branch 22 is connected to the first input end of the differential voltage sampling module 30 as the output end of the voltage dividing module 20. The first end of the third voltage dividing branch 24 is connected to the second phase line or the neutral line as the third input end of the voltage dividing module 20, and the second end of the third voltage dividing branch 24 is connected to the first input end of the differential voltage sampling module 30 as the output end of the voltage dividing module 20. Furthermore, when the switch unit 21 is turned on, the first end of the second voltage-dividing branch 23 is connected to the protective ground wire as the second input end of the voltage-dividing module 20, the second end of the second voltage-dividing branch 23 is connected to the controlled first end of the switch unit 21, and the controlled second end of the switch unit 21 is connected to the first input end of the differential voltage sampling module 30 as the output end of the voltage-dividing module 20.

[0061] Specifically, in this embodiment, the voltage dividing module 20 includes, in addition to the switch unit 21, a first voltage dividing branch 22 composed of at least one voltage dividing resistor, a third voltage dividing branch 24 composed of at least one voltage dividing resistor, and a second voltage dividing branch 23 composed of a grounding resistor connected when the switch unit 21 is turned on. Figure 8 The voltage dividing module may include a switch unit composed of a switch tube Q45 and a switch isolation device U43, a first voltage dividing branch composed of voltage dividing resistors R750, R751 and R752, a third voltage dividing branch composed of voltage dividing resistors R753, R754 and R755, and a second voltage dividing branch composed of a grounding resistor R747 connected when the switch tube Q45 and the switch isolation device U43 are both turned on.

[0062] In this embodiment, the first end of the first voltage-dividing branch 22 is connected to the first phase line or the neutral line as the first input end of the voltage-dividing module 20, and the second end thereof is connected to the first input end of the differential voltage sampling module 30 as the output end of the voltage-dividing module 20. At the same time, the first end of the third voltage-dividing branch 24 is connected to the second phase line or the neutral line as the third input end of the voltage-dividing module 20, and the second end thereof is also connected to the first input end of the differential voltage sampling module 30 as the output end of the voltage-dividing module 20. In addition, when the switch unit 21 is turned on, the first end of the second voltage-dividing branch 23 is connected to the protective ground line as the second input end of the voltage-dividing module 20, and the second end thereof is connected to the controlled first end of the switch unit 21, and the controlled second end of the switch unit 21 is connected to the first input end of the differential voltage sampling module 30 again as the output end of the voltage-dividing module 20. Through the above circuit, the voltage-dividing module 20 can adjust the voltage-dividing path according to the state of the switch unit 21, thereby outputting different sampling voltages.

[0063] The above embodiment can realize accurate voltage division sampling of the first phase line or neutral line, the second phase line or neutral line and the protective ground line voltage by setting a switch unit and multiple voltage division branches in the voltage division module. The above circuit can more accurately judge the grounding state of the power system by connecting multiple voltage division branches for voltage division sampling, thereby improving the accuracy and reliability of detection. In addition, the above circuit has good flexibility and adaptability, and can adjust its connection mode according to different power system environments, thereby improving the flexibility of device application.

[0064] In one embodiment, Figure 5 As shown, the first input terminal of the voltage divider module 20 is connected to the first phase line, and the third input terminal is connected to the second phase line. In this connection mode, the voltage divider module 20 can be used to output the sampled voltage of the first phase line and the second phase line as the first sampled voltage when the switch unit 21 is disconnected, and output the sampled voltage of the first phase line, the second phase line and the protective ground line as the second sampled voltage when the switch unit 21 is turned on. Or, as Figure 6 As shown, the first input terminal of the voltage divider module 20 is connected to the first phase line, and the third input terminal is connected to the neutral line. In this connection mode, the voltage divider module 20 can be used to output the sampled voltage of the first phase line and the neutral line after the voltage is divided as the first sampled voltage when the switch unit 21 is disconnected, and output the sampled voltage of the first phase line, the neutral line and the protective ground line after the voltage is divided as the second sampled voltage when the switch unit 21 is turned on. Or, as Figure 7 As shown, the first input terminal of the voltage divider module 20 is connected to the neutral line, and the third input terminal is connected to the second phase line. In this connection mode, the voltage divider module 20 can be used to output the sampled voltage of the neutral line and the second phase line after voltage division as the first sampled voltage when the switch unit 21 is disconnected, and to output the sampled voltage of the neutral line, the second phase line and the protective ground line after voltage division as the second sampled voltage when the switch unit 21 is turned on.

[0065] Specifically, in this embodiment, the voltage divider module 20 has a first input terminal and a third input terminal, wherein the first input terminal can be connected to the first phase line or the neutral line, and the third input terminal can be connected to the second phase line or the neutral line. The first end of the first voltage divider branch connected to the first phase line or the neutral line and the second end of the third voltage divider branch connected to the second phase line and the neutral line are both connected to the measured point, and the voltage of the measured point is used as the output of the voltage divider module, that is, by making the constituent elements of the first voltage divider branch and the third voltage divider branch the same as the second end connection point, the first end of the first voltage divider branch and the third voltage divider branch, that is, the first input terminal and the third input terminal of the voltage divider module 20 are interchangeable, in this way, the user can complete the voltage detection without following specific rules when wiring, with high fault tolerance and simple operation. In addition, when the switch unit 21 is in the disconnected state, the voltage divider module 20 can output the voltage divided sampling voltage between the first phase line and the second phase line, the first phase line and the neutral line, or the neutral line and the second phase line, that is, the first sampling voltage, according to the connection status of the input terminal. When the switch unit 21 is turned on, the voltage dividing module 20 can include the protective ground line in the voltage dividing range, and output a voltage dividing sampling voltage including the first phase line, the second phase line, the neutral line (according to the input terminal connection status) and the protective ground line, that is, the second sampling voltage. Through the above circuit connection method, the voltage dividing module 20 can flexibly adjust its output according to the configuration and detection requirements of different power systems, thereby providing strong data support for subsequent voltage sampling and grounding status judgment.

[0066] The above-mentioned embodiment can realize accurate voltage division sampling of multi-phase line voltage and protective ground line voltage of the power system by designing different circuit connection modes for the voltage division module. Based on this, the above-mentioned circuit can effectively improve the accuracy and reliability of voltage monitoring and avoid potential safety hazards caused by poor grounding. Secondly, by setting the constituent elements of the first voltage division branch and the third voltage division branch to be the same as the second end connection point, the fault tolerance of the user's installation can be increased, and the installation is simple. In addition, the above-mentioned circuit has high versatility and adaptability, can be applied to the configuration and detection requirements of different power systems, and provide a strong guarantee for the safe operation of the power system.

[0067] In one embodiment, Figure 8 As shown, the differential voltage sampling module includes a differential amplifier unit composed of an operational amplifier U44B and a resistor, and the resistor includes a feedback resistor R764 between the negative input terminal and the output terminal of the operational amplifier U44B. Among them, the positive input terminal of the differential amplifier unit is connected to the output terminal of the voltage divider module as the first input terminal of the differential voltage sampling module, and the positive input terminal of the differential amplifier unit is also connected to the constant voltage source Vref through the sampling resistor R760; the negative input terminal of the differential amplifier unit is connected to the second phase line or the neutral line as the second input terminal of the differential voltage sampling module; and the output terminal of the differential amplifier unit is connected to the input terminal PE_DET_AD of the control module.

[0068] Specifically, in this embodiment, the positive input terminal of the differential amplifier unit is connected to the output terminal of the voltage divider module, and receives a voltage signal as its first input terminal. At the same time, its positive input terminal is also connected to the constant voltage source Vref through a sampling resistor R760 to ensure the stability and accuracy of the input signal. Further, the negative input terminal of the differential amplifier unit is connected to the second phase line or the neutral line as the second input terminal, and is used to receive another voltage signal. In this embodiment, the output signal of the differential amplifier unit can be output to the input terminal PE_DET_AD of the control module for subsequent processing and analysis by the control module.

[0069] The above embodiment can effectively amplify the voltage difference between the two input terminals and suppress the interference of the common mode signal by setting the differential amplifier unit in the differential voltage sampling module, thereby improving the signal-to-noise ratio of the sampling signal. In addition, the negative input terminal of the differential amplifier unit is connected to the second phase line or the neutral line as the second input terminal, and the positive input terminal is connected to the first phase line or the neutral line as the first input terminal. Since the voltage value of the phase line or the neutral line is related to the voltage system of the previous stage, it is stable to use the phase line and the neutral line as the reference voltage of the negative input terminal. If the ground line is used as the reference voltage, the induced voltage at the left end of the grounding resistor R747 will be affected by the change of the power grid state and become unstable, resulting in inaccurate measurement. Therefore, the above circuit can enhance the stability and reliability of the input signal by setting the phase line or the neutral line as the negative input terminal of the differential amplifier unit and setting the voltage of the phase line or the neutral line as the differential reference voltage, so that the differential voltage sampling module can work stably in a complex electrical environment. In addition, the introduction of a constant voltage source Vref can adjust the output voltage of the operational amplifier to the sampling range of the MCU.

[0070] In one embodiment, Figure 5 and Figure 7 As shown, the negative input terminal of the differential amplifier unit is connected to the second phase line as the second input terminal of the differential voltage sampling module 30. In this connection mode, the differential amplifier unit can be used to receive a first differential sampling voltage between the first sampling voltage and the sampling voltage of the second phase line as the differential sampling result of the first sampling voltage when the switch unit 21 is disconnected, and receive a second differential sampling voltage between the second sampling voltage and the sampling voltage of the second phase line as the differential sampling result of the second sampling voltage when the switch unit 21 is turned on. Or, as Figure 6 As shown, the negative input terminal of the differential amplifier unit is connected to the neutral line as the second input terminal of the differential voltage sampling module 30. In this connection mode, the differential amplifier unit can be used to receive a first differential sampling voltage between the first sampling voltage and the sampling voltage of the neutral line as the differential sampling result of the first sampling voltage when the switch unit 21 is disconnected, and receive a second differential sampling voltage between the second sampling voltage and the sampling voltage of the neutral line as the differential sampling result of the second sampling voltage when the switch unit 21 is turned on.

[0071] Specifically, in this embodiment, the negative input terminal of the differential amplifier unit serves as the second input terminal of the differential voltage sampling module 30, which can be connected to the second phase line (such as Figure 5 and Figure 7 as shown), or it can be connected to the neutral line (as Figure 6As shown). Wherein, when the negative input terminal of the differential amplifier unit is connected to the second phase line, the differential amplifier unit can collect the first differential sampling voltage between the first sampling voltage and the second phase line voltage when the switch unit 21 is in the disconnected state, and use it as the differential sampling result of the first sampling voltage; when the switch unit 21 is turned on, the differential amplifier unit can collect the second differential sampling voltage between the second sampling voltage and the second phase line voltage, and use it as the differential sampling result of the second sampling voltage. If the negative input terminal of the differential amplifier unit is connected to the neutral line instead, then in different states of the switch unit 21, the differential amplifier unit will collect the differential voltage between the first sampling voltage and the neutral line voltage, and the differential voltage between the second sampling voltage and the neutral line voltage, and use them as the corresponding differential sampling results.

[0072] The above embodiment can realize differential sampling of two different sampling voltages by flexibly connecting the differential amplifier unit to the second phase line or the neutral line. The above circuit not only improves the accuracy and stability of voltage sampling, but also effectively suppresses the interference of common mode noise. Moreover, the system can accurately obtain the differential voltage between the sampling voltage and the reference voltage (the second phase line or the neutral line) in different states of the switch unit, thereby providing reliable data support for subsequent grounding detection.

[0073] In one embodiment, the differential voltage sampling module further includes a first voltage dividing unit and a second voltage dividing unit, wherein the first voltage dividing unit is connected between the output end of the voltage dividing module and the positive input end of the differential amplification unit, and the second voltage dividing unit is connected between the second phase line and the negative input end of the differential amplification unit, or the second voltage dividing unit is connected between the neutral line and the negative input end of the differential amplification unit.

[0074] Specifically, the first voltage divider unit is connected between the output end of the voltage divider module and the positive input end of the differential amplifier unit, which can play a role in voltage division; the second voltage divider unit is connected between the second phase line (or neutral line, depending on the specific design) and the negative input end of the differential amplifier unit, which can also achieve the role of voltage division. In this embodiment, the first voltage divider unit and the second voltage divider unit are symmetrically arranged, and such a design can ensure the balance and stability of the circuit. For example, referring to Figure 8The first voltage divider unit is composed of resistors R756, R757 and R758 connected in series, and the second voltage divider unit is composed of resistors R761, R762 and R763 connected in series. These resistors can jointly reduce the voltage on the phase line or the neutral line, so that the voltage input to the differential amplifier unit is low enough to make the voltage output from the differential amplifier unit meet the sampling range of the MCU. The sampling resistor R760 and the feedback resistor R764 also have a voltage dividing effect, so that the output voltage of the differential amplifier unit meets the sampling range of the MCU. The differential voltage sampling module also includes a current limiting unit, which is played by the filter resistor R759. The current limiting unit is used to prevent excessive current from entering the MCU and causing damage to the MCU.

[0075] The above embodiment introduces the first voltage divider unit and the second voltage divider unit to reduce the high voltage step by step to the voltage range that the MCU can sample. The multiple resistors gradually reduce the voltage to avoid the problem of excessive resistor volume caused by a single resistor performing voltage reduction. The current limiting unit can control the current output by the differential amplifier unit to avoid MCU damage or performance degradation due to excessive current.

[0076] In one embodiment, the differential voltage sampling module further includes a first isolation unit and a second isolation unit, wherein the first isolation unit is connected in series with the first voltage divider unit between the output end of the voltage divider module and the positive input end of the differential amplifier unit, the second isolation unit is connected in series with the second voltage divider unit between the second phase line and the negative input end of the differential amplifier unit, or the second isolation unit is connected in series with the second voltage divider unit between the neutral line and the negative input end of the differential amplifier unit.

[0077] Specifically, the first isolation unit and the first voltage divider unit are connected in series between the output end of the voltage divider module and the positive input end of the differential amplifier unit, which can play the role of isolation and voltage division; the second isolation unit and the second voltage divider unit are connected in series between the second phase line (or neutral line, depending on the specific design) and the negative input end of the differential amplifier unit, which can also achieve signal isolation and voltage division. In this embodiment, the first isolation unit and the second isolation unit are symmetrically arranged, and such a design can ensure the balance and stability of the circuit. For example, referring to Figure 8, the first isolation unit can be composed of an isolation capacitor C474, and the second isolation unit can be composed of an isolation capacitor C475. As electrical isolation devices, they have the characteristics of withstanding high voltage. Furthermore, the first voltage divider unit is composed of resistors R756, R757 and R758 connected in series, and the second voltage divider unit is composed of resistors R761, R762 and R763 connected in series. These resistors can jointly reduce the voltage on the phase line or neutral line, so that the voltage input to the differential amplifier unit is low enough to make the voltage output from the differential amplifier unit meet the sampling range of the MCU. The sampling resistor R760 and the feedback resistor R764 also have a voltage dividing effect, so that the output voltage of the differential amplifier unit meets the sampling range of the MCU.

[0078] The differential voltage sampling module also includes a current limiting unit, which is played by the filter resistor R759. The current limiting unit is used to prevent excessive current from entering the MCU and causing damage to the MCU.

[0079] The above embodiment can significantly improve the reliability and safety of the differential voltage sampling module by introducing the first isolation unit, the first voltage divider unit, the second isolation unit, the second voltage divider unit and the current limiting unit. Among them, the voltage divider unit reduces the high voltage step by step to the voltage range that the MCU can sample through multiple resistors, and the multiple resistors gradually reduce the voltage to avoid the problem of excessive resistance volume caused by a single resistor performing voltage reduction. The isolation unit can effectively perform electrical isolation between high voltage and low voltage. The current limiting unit can control the current output by the differential amplifier unit to avoid damage to the MCU or performance degradation caused by excessive current.

[0080] In one embodiment, the differential voltage sampling module further includes a first filtering unit and / or a first protection unit. The first filtering unit is arranged between the negative input terminal of the differential amplifier unit and the output terminal of the differential amplifier unit, and / or between the input terminal and the ground terminal of the control module, and / or between the output terminal of the differential amplifier unit and the input terminal of the control module. And / or, the first protection unit is arranged between the output terminal and the power supply terminal of the differential amplifier unit, and between the output terminal and the ground terminal of the differential amplifier unit.

[0081] Specifically, the first filtering unit can be arranged between the negative input terminal and the output terminal of the differential amplifier unit, and / or, between the input terminal and the ground terminal of the control module, and / or, between the output terminal of the differential amplifier unit and the input terminal of the control module, and is used to filter out high-frequency noise and interference in the sampled signal, so as to improve the purity and stability of the signal. Furthermore, the first protection unit can be arranged at the output terminal of the differential amplifier unit to protect the differential amplifier unit from damage. For example, referring to Figure 8The filter unit includes filter capacitors C476, C477 and filter resistor R759, wherein the filter capacitor C477 can be used alone or in combination with the filter resistor R759 and another filter capacitor C476 to form a low-pass filter circuit and filter out high-frequency noise in the signal. In addition, a diode D95 is connected between the differential amplifier circuit and the power supply terminal and the ground terminal. By setting the diode D95, when the output signal is abnormal, such as the voltage is too high or too low, the diode can be turned on or off, thereby protecting the differential amplifier unit from damage, thereby enhancing the reliability and safety of the circuit.

[0082] The above embodiment can significantly improve the performance and reliability of the differential voltage sampling module by setting the first filtering unit and the first protection unit in the differential voltage sampling module. Among them, the first filtering unit can effectively filter out high-frequency noise and interference in the sampling signal, and improve the purity and stability of the signal. The first protection unit can enhance the protection capability of the module, and can timely cut off or limit harmful current under abnormal conditions, protect the differential amplifier unit and other circuit components from damage, and extend the service life of the module.

[0083] In one embodiment, Figure 8 As shown, the switch unit includes a switch tube and a switch isolation device. Among them, the control end of the switch tube is connected to the output end of the control module as the control end of the switch unit, and the control end of the switch tube is also connected to the output end of the control module through a voltage-dividing resistor, and is connected to the ground end through a voltage-dividing resistor. The first end of the switch tube is connected to the ground end, the second end of the switch tube is connected to the negative input end of the switch isolation device, the positive input end of the switch isolation device is connected to the power supply end, the first output end of the switch isolation device is connected to the protective ground wire as the controlled first end of the switch unit, and the second output end of the switch isolation device is connected to the first input end of the differential voltage sampling module as the controlled second end of the switch unit.

[0084] Specifically, Figure 8As shown, the switch unit can be designed in combination with a switch tube and a switch isolation device. Among them, the control end of the switch tube Q45, as the control end of the switch unit, can be connected to the output end PE_DET_CTR of the control module, and is used to receive the ground detection signal to realize the switching action. At the same time, the control end of the switch tube Q45 is also connected to the output end PE_DET_CTR of the control module through a voltage-dividing resistor R746, and is connected to the ground end through a voltage-dividing resistor R749. The voltage-dividing resistor is used to divide the ground detection signal, reduce the voltage of the output end PE_DET_CTR of the control module, and achieve the ability to control whether the switch tube Q45 is turned on or not, thereby realizing the control of whether the switch isolation device is turned on or not. At the same time, the resistors R746 and R749 can provide a release loop when the external signal interference in the circuit generates high voltage on the capacitor, and introduce it into the ground end, which will not cause the switch tube Q45 to open, so the resistors R746 and R749 also have the function of keeping the system stable. Furthermore, the first end of the switch tube Q45 is grounded, and the second end is connected to the negative input end of the switch isolation device U43. The positive input end of the switch isolation device U43 is connected to the power supply end VCC through the current limiting resistor R748 to ensure that the current can be reasonably limited when the switch is in action, and the diode in the switch isolation device U43 is protected from damage by large current. The first output end of the switch isolation device U43 is connected to the protective ground wire as the controlled first end of the switch unit, and the second output end is connected to the first input end of the differential voltage sampling module as the controlled second end of the switch unit, and is used to transmit a voltage signal when the switch is turned on.

[0085] The above embodiment can realize flexible control of the input signal of the control module by setting the switch tube and the switch isolation device in the switch unit. Among them, the voltage divider resistor can reduce the voltage impact of the control signal on the switch tube, and improve the reliability of the switch unit. At the same time, the switch isolation device can provide electrical isolation and enhance the safety of the system to prevent current leakage or short circuit caused by faults.

[0086] In one embodiment, Figure 8 As shown, the switch unit further includes a second filtering unit and / or a second protection unit. The second filtering unit is arranged between the control terminal and the ground terminal of the switch tube, and / or the second protection unit is arranged between the first output terminal and the second output terminal of the switch isolation device.

[0087] Specifically, Figure 8 As shown, the switch unit also includes a second filtering unit and / or a second protection unit. The second filtering unit is arranged between the control terminal and the ground terminal of the switch tube Q45, and can be used to filter out high-frequency noise and interference in the control signal and ensure that the switch tube Q45 can receive a stable and accurate ground detection signal. Figure 8The second protection unit is arranged between the first output terminal and the second output terminal of the switch isolation device U43. When an abnormal voltage appears at the output terminal of the switch isolation device U43, such as when the voltage is too high, the abnormal voltage can be limited to a safe range by the breakdown conduction of the bidirectional breakdown diode, so as to protect the subsequent circuit from damage, such as Figure 8 The bidirectional breakdown diode D94 in.

[0088] The above embodiment can significantly improve the performance and reliability of the switch unit by setting the second filter unit and the second protection unit in the switch unit. Among them, the second filter unit can effectively filter out high-frequency noise and interference in the control signal, ensuring that the switch tube can receive clear and accurate control instructions, thereby improving the accuracy and stability of the switch action. The second protection unit can enhance the self-protection ability of the switch unit, and can respond in time under abnormal voltage conditions, limiting the abnormal voltage within a safe range, thereby avoiding circuit damage or safety accidents caused by excessive voltage.

[0089] In one embodiment, a grounding detection method is provided. The method can be applied to the grounding detection device shown in any of the above embodiments, such as Fig. 9 As shown, the above method includes:

[0090] Step 101, in response to a grounding detection instruction, output a first grounding detection signal to disconnect the protection ground line from the voltage divider module, and receive a first differential sampling voltage between a first sampling voltage and a preset reference voltage, wherein the reference voltage is a sampling voltage of a second phase line or a neutral line.

[0091] Step 102: output a second ground detection signal to connect the protection ground line to the voltage dividing module and receive a second differential sampling voltage between the second sampling voltage and the reference voltage.

[0092] Step 103: Determine a ground detection result based on the difference between the first differential sampling voltage and the second differential sampling voltage.

[0093] Specifically, the method for the grounding detection device to perform grounding detection is as follows: First, the control module in the grounding detection device responds to the grounding detection instruction, outputs a first grounding detection signal to disconnect the connection between the protective ground wire and the voltage divider module, and receives a first differential sampling voltage between the first sampling voltage (at this time, the voltage after the phase line voltage and the voltage divider resistor act) and the preset reference voltage (the sampling voltage of the second phase line or the neutral line). Then, the control module can output a second grounding detection signal to connect the protective ground wire to the voltage divider module, and receive a second differential sampling voltage between the second sampling voltage (at this time, the voltage after the phase line voltage, the protective ground wire and the voltage divider resistor act together) and the same reference voltage. Finally, the control module can determine the grounding detection result by calculation and analysis based on the difference between the two differential sampling voltages.

[0094] The grounding detection method provided in the above embodiment obtains the grounding resistance by comparing the voltage of the measured point on the phase line or also including the neutral line, and the voltage difference after the voltage of the measured point on the phase line or also including the neutral line is divided by the grounding voltage. The difference between the two measurements is only whether it is grounded. Therefore, it can effectively avoid the influence of whether the grid state is balanced, the voltage drop caused by the impedance on the transmission cable, and the internal parameters of the charging device on the grounding detection result, thereby effectively improving the accuracy of grounding detection and the accuracy under different grid states. In addition, when performing grounding detection, the above grounding detection method does not need to rely on the access of the neutral line, but can selectively access the first phase line and the second phase line, so that the grounding detection method can be widely applied to a variety of power systems, including TN systems, TT systems, and split-phase transformer systems, etc., greatly improving the versatility and practicality of the grounding detection device. Based on this, the above method can effectively solve the problems of difficult and inaccurate grounding detection of charging devices, thereby providing a strong guarantee for the safe use of charging devices.

[0095] In such Figures 4 to 7 As shown, in different connection modes, the implementation methods of step 101 and step 102 are different. The implementation methods in different connection modes are now described through the following embodiments:

[0096] In one embodiment, step 101 can be implemented by the following method: receiving a first differential sampling voltage between a first sampling voltage and a sampling voltage of a second phase line, wherein the first sampling voltage is a sampling voltage after the first phase line is divided, or a sampling voltage after the first phase line and the second phase line are divided. Step 102 can be implemented by the following method: receiving a second differential sampling voltage between a second sampling voltage and a sampling voltage of a second phase line, wherein the second sampling voltage is a sampling voltage after the first phase line and the protective ground line are divided, or a sampling voltage after the first phase line, the second phase line and the protective ground line are divided.

[0097] Specifically, refer to Figure 4 When the voltage divider module 20 is only connected to the first phase line, the first sampled voltage in step 101 is the sampled voltage of the first phase line after voltage division, and the second sampled voltage in step 102 is the sampled voltage of the voltage between the first phase line and the protective ground line after voltage division. Figure 5 When the voltage divider module 20 is connected to the first phase line and the second phase line at the same time, the first sampling voltage in step 101 is the sampling voltage after the first phase line and the second phase line are divided, and the second sampling voltage in step 102 is the sampling voltage after the first phase line, the second phase line and the protective ground line are divided.

[0098] In this embodiment, the adaptability of the circuit in different connection modes can be improved by adaptively collecting the corresponding voltage division signal as the sampling voltage through the ground detection device in different circuit connection modes.

[0099] In one embodiment, step 101 can be implemented by the following method: receiving a first differential sampling voltage between a first sampling voltage and a sampling voltage of a neutral line, wherein the first sampling voltage is a sampling voltage after the first phase line is divided, or a sampling voltage after the first phase line and the neutral line are divided. Step 102 can be implemented by the following method: receiving a second differential sampling voltage between a second sampling voltage and a sampling voltage of a neutral line, wherein the second sampling voltage is a sampling voltage after the first phase line and the protective ground line are divided, or a sampling voltage after the first phase line, the neutral line, and the protective ground line are divided.

[0100] Specifically, refer to Figure 4 When the voltage divider module 20 is only connected to the first phase line, the first sampled voltage in step 101 is the sampled voltage of the first phase line after voltage division, and the second sampled voltage in step 102 is the sampled voltage of the voltage between the first phase line and the protective ground line after voltage division. Figure 6 When the voltage divider module 20 is connected to the first phase line and the neutral line at the same time, the first sampling voltage in step 101 is the sampling voltage after the first phase line and the neutral line are divided, and the second sampling voltage in step 102 is the sampling voltage after the first phase line, the neutral line and the protective ground line are divided.

[0101] In this embodiment, the adaptability of the circuit in different connection modes can be improved by adaptively collecting the corresponding voltage division signal as the sampling voltage through the ground detection device in different circuit connection modes.

[0102] In one embodiment, step 101 can be implemented by the following method: receiving a first differential sampling voltage between a first sampling voltage and a sampling voltage of a second phase line, wherein the first sampling voltage is a sampling voltage after a neutral line and a second phase line are divided. Step 102 can be implemented by the following method: receiving a second differential sampling voltage between a second sampling voltage and a sampling voltage of a second phase line, wherein the second sampling voltage is a sampling voltage after a neutral line, a second phase line, and a protective ground line are divided.

[0103] Specifically, refer to Figure 7 When the voltage divider module 20 is connected to the neutral line and the second phase line at the same time, the first sampled voltage in step 101 is the sampled voltage after the neutral line and the second phase line are divided, and the second sampled voltage in step 102 is the sampled voltage after the neutral line, the second phase line and the protective ground line are divided.

[0104] The above embodiments can realize comprehensive and accurate collection of power system voltage information by flexibly adjusting the specific implementation methods of step 101 and step 102 under different connection modes. Through the above method, not only the flexibility and adaptability of voltage sampling are improved, but also various complex power system connection modes can be effectively handled to ensure the accuracy and reliability of sampled data.

[0105] In one embodiment, a grounding detection result is determined based on a difference between a first differential sampling voltage and a second differential sampling voltage, including: when the duration for which the difference between the first differential sampling voltage and the second differential sampling voltage is greater than a preset voltage threshold exceeds a preset duration, a poor grounding detection result is generated.

[0106] Specifically, the grounding detection result can be generated based on the difference between the first differential sampling voltage and the second differential sampling voltage. In this embodiment, the control device can continuously monitor the difference between the two differential sampling voltages and calculate the length of time that the difference exceeds the preset voltage threshold. When it is detected that the difference between the first differential sampling voltage and the second differential sampling voltage is greater than the preset voltage threshold for a period of time that exceeds the preset time, it is considered that there is a poor grounding situation. At this time, the control module can generate a poor grounding detection result. In this embodiment, the voltage threshold can be set according to the normal operating state of the power system and the possible grounding fault situation. The threshold can be used to distinguish between normal voltage fluctuations and potential grounding problems.

[0107] The above embodiment uses the difference between the first differential sampling voltage and the second differential sampling voltage as the basis for grounding detection, and sets the corresponding voltage threshold and duration threshold, which can effectively improve the accuracy and reliability of grounding detection, help distinguish normal voltage fluctuations and potential grounding faults in the power system, and avoid unnecessary shutdown or maintenance due to misjudgment. At the same time, the above embodiment can promptly remind the operation and maintenance personnel to take corresponding measures to troubleshoot and repair the fault by generating the detection result of poor grounding, thereby effectively ensuring the safe and stable operation of the power system.

[0108] In one embodiment, after generating the detection result of poor grounding, the method further includes: outputting a poor grounding alarm signal, and / or outputting a switch control signal for controlling the power switch to be disconnected to stop charging.

[0109] Specifically, after determining that the charging device has poor grounding, the control module can take a series of measures to ensure the safety of the power system. On the one hand, the control module can output a poor grounding alarm signal, which can be presented in a variety of ways such as sound, light and electricity to attract the attention of the operation and maintenance personnel, thereby reminding the operation and maintenance personnel to take appropriate measures in time to troubleshoot and repair the fault. On the other hand, in order to avoid equipment damage or safety accidents that may be caused by poor grounding, the control module can also output a switch control signal that controls the power switch to disconnect to stop the charging process. This measure can quickly cut off the power supply related to the fault point to prevent the fault from further expanding, thereby protecting the safety of equipment and personnel.

[0110] The above embodiments can effectively improve the safety and reliability of the power system by outputting an alarm signal and / or controlling the power switch to disconnect in time after detecting a poor grounding. Among them, the output alarm signal can remind the operation and maintenance personnel to pay attention to and deal with the grounding fault in time, so as to reduce the time for troubleshooting and repairing the fault and reduce the losses caused by the fault. At the same time, controlling the power switch to disconnect can immediately stop the charging process to prevent the fault point from continuing to receive power supply, thereby avoiding equipment damage or safety accidents.

[0111] In one embodiment, the ground detection method further includes the following steps: in a charging state, periodically generating a ground detection instruction, and performing ground detection in response to the ground detection instruction periodically.

[0112] Specifically, in order to ensure safety during the charging process, the charging device can periodically generate a grounding detection instruction in the charging state. Among them, the grounding detection instruction can be automatically and continuously generated to ensure that the grounding status of the system can be continuously monitored. In this embodiment, whenever the system receives a grounding detection instruction, it will immediately start the grounding detection process, including collecting the first differential sampling voltage and the second differential sampling voltage, and calculating the difference between them, and comparing them with the preset voltage threshold and duration threshold to determine whether there is a poor grounding situation. Through such periodic detection, the system can promptly detect and respond to potential grounding faults and ensure the safety of the charging process.

[0113] The above embodiment can realize continuous monitoring of the grounding status during the charging process by setting periodic grounding detection instructions. This periodic detection method not only improves the real-time and accuracy of grounding detection, but also effectively reduces the safety risks caused by grounding faults. In addition, by timely discovering and handling poor grounding conditions, the system can avoid equipment damage or safety accidents caused by faults, ensuring the smooth progress of the charging process.

[0114] In one embodiment, a charging device is provided, which includes a grounding detection device as described in any of the above embodiments, and can execute a grounding detection method as described in any of the above embodiments. In this embodiment, the above charging device can be a variety of charging devices such as an AC pile, a DC pile, a charging pile, and a charging terminal derived from the charging pile. For the specific implementation of the above charging device, please refer to the grounding detection device and grounding detection method described in any of the above embodiments, which will not be repeated here.

[0115] It should be noted that the information (including but not limited to user information, device information, etc.) and data (including but not limited to data for analysis, data for storage, data for display, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. In addition, the numbers corresponding to the various steps in the above embodiments only serve as identification and are not used as a limitation on the order in which the steps are executed. The order in which the steps are executed in each embodiment can be set according to actual conditions.

[0116] The embodiment of the present application also provides a computer device, which can be a personal computer, a server, a network device, etc. The computer device includes a bus, a processor, a memory and a communication interface, and can also include an input and output interface and a display device. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store location information. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, the steps in each method embodiment are implemented.

[0117] Those skilled in the art will appreciate that the structure of the above-mentioned computer device is only a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components, or combine certain components, or have a different arrangement of components.

[0118] In one embodiment, a computer-readable storage medium is provided. The computer-readable storage medium may be non-volatile or volatile, and stores a computer program thereon. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0119] In one embodiment, a computer program product is provided, including a computer program, which implements the steps in the above method embodiments when executed by a processor.

[0120] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0121] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0122] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the present application. It should be noted that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A grounding detection device, characterized in that: The ground detection device comprises a control module, a voltage dividing module and a differential voltage sampling module, wherein the voltage dividing module comprises a switch unit, wherein: The output end of the control module is connected to the control end of the switch unit, and is used to respond to the ground detection instruction and output a ground detection signal; The first input end of the voltage divider module is connected to the first phase line or the neutral line, and the second input end is connected to the protective ground line through the switch unit; when the switch unit is disconnected, the voltage divider module outputs a first sampled voltage after the first phase line or the neutral line is divided, and when the switch unit is turned on, the voltage divider module outputs a second sampled voltage after the first phase line or the neutral line and the protective ground line are divided, wherein the switch unit is turned on or off based on the ground detection signal; The first input end of the differential voltage sampling module is connected to the output end of the voltage dividing module, and the second input end is connected to the second phase line or the neutral line, and is used to perform differential sampling on the first sampling voltage when the switch unit is disconnected, and perform differential sampling on the second sampling voltage when the switch unit is turned on; The input end of the control module is connected to the output end of the differential voltage sampling module, and is used to determine a ground detection result based on a differential sampling result of the first sampling voltage and a differential sampling result of the second sampling voltage.

2. The grounding detection device according to claim 1, characterized in that: The voltage dividing module further includes a first voltage dividing branch composed of at least one voltage dividing resistor, wherein: The first end of the first voltage dividing branch is connected to the first phase line as the first input end of the voltage dividing module, and the second end of the first voltage dividing branch is connected to the first input end of the differential voltage sampling module as the output end of the voltage dividing module; When the switch unit is turned on, the voltage divider module also includes a second voltage divider branch composed of a grounding resistor; the first end of the second voltage divider branch is connected to the protective ground wire as the second input end of the voltage divider module, the second end of the second voltage divider branch is connected to the controlled first end of the switch unit, and the controlled second end of the switch unit is connected to the first input end of the differential voltage sampling module as the output end of the voltage divider module.

3. The grounding detection device according to claim 2, characterized in that: The first input end of the voltage divider module is connected to the first phase line; the voltage divider module is used to output the sampled voltage of the first phase line after voltage division as the first sampling voltage when the switch unit is disconnected, and to output the sampled voltage of the first phase line and the protective ground line after voltage division as the second sampling voltage when the switch unit is turned on.

4. The grounding detection device according to claim 1, characterized in that: The voltage dividing module further includes a first voltage dividing branch composed of at least one voltage dividing resistor, and a third voltage dividing branch composed of at least one voltage dividing resistor, wherein: The first end of the first voltage dividing branch is connected to the first phase line or the neutral line as the first input end of the voltage dividing module, and the second end of the first voltage dividing branch is connected to the first input end of the differential voltage sampling module as the output end of the voltage dividing module; The first end of the third voltage dividing branch is connected to the second phase line or the neutral line as the third input end of the voltage dividing module, and the second end of the third voltage dividing branch is connected to the first input end of the differential voltage sampling module as the output end of the voltage dividing module; When the switch unit is turned on, the voltage divider module also includes a second voltage divider branch composed of a grounding resistor; the first end of the second voltage divider branch is connected to the protective ground wire as the second input end of the voltage divider module, the second end of the second voltage divider branch is connected to the controlled first end of the switch unit, and the controlled second end of the switch unit is connected to the first input end of the differential voltage sampling module as the output end of the voltage divider module.

5. The grounding detection device according to claim 4, characterized in that: The first input end of the voltage divider module is connected to the first phase line, and the third input end is connected to the second phase line; the voltage divider module is used to output the divided sampling voltage of the first phase line and the second phase line as the first sampling voltage when the switch unit is disconnected, and output the divided sampling voltage of the first phase line, the second phase line and the protective ground line as the second sampling voltage when the switch unit is turned on; or The first input end of the voltage divider module is connected to the first phase line, and the third input end is connected to the neutral line; the voltage divider module is used to output the divided voltage of the first phase line and the neutral line as the first sampling voltage when the switch unit is disconnected, and output the divided voltage of the first phase line, the neutral line and the protective ground line as the second sampling voltage when the switch unit is turned on; or, The first input end of the voltage divider module is connected to the neutral line, and the third input end is connected to the second phase line; the voltage divider module is used to output the sampled voltage of the neutral line and the second phase line after voltage division as the first sampled voltage when the switch unit is disconnected, and to output the sampled voltage of the neutral line, the second phase line and the protective ground line after voltage division as the second sampled voltage when the switch unit is turned on.

6. The grounding detection device according to any one of claims 1 to 5, characterized in that: The differential voltage sampling module includes a differential amplification unit composed of an operational amplifier and a resistor, wherein: The positive input terminal of the differential amplifier unit is connected to the output terminal of the voltage divider module as the first input terminal of the differential voltage sampling module, and the positive input terminal of the differential amplifier unit is also connected to the constant voltage source through a sampling resistor; The negative input terminal of the differential amplifier unit is connected to the second phase line or the neutral line as the second input terminal of the differential voltage sampling module; the output terminal of the differential amplifier unit is connected to the input terminal of the control module.

7. A grounding detection method, characterized in that: The method is applied in the grounding detection device according to any one of claims 1 to 6, and the method comprises: In response to the grounding detection instruction, a first grounding detection signal is output to disconnect the connection between the protective ground line and the voltage dividing module, and a first differential sampling voltage between the first sampling voltage and a preset reference voltage is received, wherein the reference voltage is a sampling voltage of the second phase line or the neutral line; Output a second ground detection signal to connect the protection ground line to the voltage dividing module, and receive a second differential sampling voltage between the second sampling voltage and the reference voltage; A ground detection result is determined based on a difference between the first differential sampling voltage and the second differential sampling voltage.

8. A charging device, characterized in that: The charging device is provided with a grounding detection device as claimed in any one of claims 1 to 6 inside.

9. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to claim 7 is implemented.

10. A computer device comprising a storage medium, a processor, and a computer program stored in the storage medium and executable on the processor, characterized in that: When the processor executes the computer program, the method according to claim 7 is implemented.

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