A detection circuit and an alternating current charging pile

Abstract

The utility model discloses an embodiment of detecting circuit and AC charging pile, detecting circuit includes: first detection terminal is used for with the first pole of the measured charging gun connection, second detection terminal is used for with the second pole of the measured charging gun connection, voltage division module is connected between first power end and ground terminal, first detection terminal and second detection terminal are all connected in series between first power end and voltage division output terminal of voltage division module, voltage division module carries out voltage division to the voltage of first power end according to the electric signal between first detection terminal and second detection terminal, control module is connected with voltage division output terminal of voltage division module, and control module determines the failure state of the measured charging gun according to the difference of voltage division signal of voltage division output terminal and preset threshold voltage, the technical scheme of the utility model embodiment has solved the problem that the reliability of charging gun short circuit fault detection of charging pile is not good, can detect short circuit fault in advance, and reduces charging security risk.

Description

Technical Field

[0001] This utility model relates to the field of detection technology, and in particular to a detection circuit and an AC charging pile. Background Technology

[0002] With the vigorous development of new energy sources, especially electric vehicles, by the nation and the international community, the existing automobile production scale has experienced explosive growth. As an indispensable basic infrastructure for electric vehicles, the demand for AC charging piles has also surged. The charging process for electric vehicles involves the transmission of high voltage and high current, making safety paramount. If a short circuit occurs at the output terminal during charging, the fault current can not only severely damage the equipment itself but also potentially cause serious accidents such as electric shock, arcing, and fire, posing a personal injury hazard and endangering lives to on-site operators or users.

[0003] Existing short-circuit protection schemes for charging piles pose significant safety hazards. Their passive protection is prone to failure due to improper installation, leading to fire risks. At the same time, their short-circuit detection circuits lack reliability in complex and variable real-world application environments, such as different test conditions, vehicle-side differences, and software timing issues, making them susceptible to damage and unable to provide stable and reliable protection.

[0004] The unreliability of short-circuit fault detection circuits in existing charging piles has become a technical problem that urgently needs to be solved in the industry. Utility Model Content

[0005] This invention provides a detection circuit and an AC charging pile to solve the problem of poor reliability in detecting short-circuit faults in the charging gun of the charging pile.

[0006] According to one aspect of the present invention, a detection circuit is provided, comprising:

[0007] The first detection terminal is used to connect to the first pole of the charging gun under test;

[0008] The second detection terminal is used to connect to the second pole of the charging gun under test; the first detection terminal and the second detection terminal are open circuits to each other;

[0009] A voltage divider module is connected between a first power supply terminal and a ground terminal; a first detection terminal is connected in series between the first power supply terminal and the voltage divider output terminal of the voltage divider module; a second detection terminal is connected in series between the first power supply terminal and the voltage divider output terminal; the voltage divider module is used to divide the voltage of the first power supply terminal according to the electrical signal between the first detection terminal and the second detection terminal.

[0010] A control module is connected to the voltage divider output terminal of the voltage divider module. The control module is used to determine the fault state of the charging gun under test based on the difference between the voltage divider signal at the voltage divider output terminal and the preset threshold voltage.

[0011] Optionally, the detection circuit further includes: a voltage follower module and a voltage regulator module;

[0012] The first terminal of the voltage follower module is connected to the voltage divider output terminal of the voltage divider module, the second terminal of the voltage follower module is connected to the first terminal of the control module and the voltage regulator module, the second terminal of the voltage regulator module is connected to the second power supply terminal, and the third terminal of the voltage regulator module is connected to the ground terminal.

[0013] Optionally, the voltage divider module includes: a first voltage divider network; a first end of the first voltage divider network is connected to the ground terminal, and a second end of the first voltage divider network is connected to the control module.

[0014] Optionally, the voltage divider module further includes a second voltage divider network; a first end of the second voltage divider network is connected to a first power supply terminal, and a second end of the second voltage divider network is connected to the first detection terminal; and / or,

[0015] A third voltage divider network; the first end of the third voltage divider network is connected to the second detection terminal, and the second end of the third voltage divider network is connected to the first end of the first voltage divider network.

[0016] Optionally, the detection circuit further includes: at least one switching module; a first terminal of the at least one switching module is connected to a second terminal of the second voltage divider network, and a second terminal of the at least one switching module is connected to the first detection terminal; and / or,

[0017] The first end of the at least one switching module is connected to the second detection terminal, and the second end of the at least one switching module is connected to the first end of the third voltage divider network.

[0018] Optionally, the at least one switching module includes a first relay, a first terminal of which is connected to a second terminal of the second voltage divider network, and a second terminal of which is connected to the first detection terminal; and / or,

[0019] The at least one switching module includes a second relay, the first end of which is connected to the second detection terminal, and the second end of which is connected to the first end of the third voltage divider network.

[0020] Optionally, the detection circuit further includes: a protection module, wherein the first and second terminals of the protection module are connected to the voltage divider output terminal of the voltage divider module, the third terminal of the protection module is connected to the third power supply terminal, the fourth terminal of the protection module is connected to the second power supply terminal, and the fifth and sixth terminals of the protection module are connected to the ground terminal; the protection module is used to control the voltage of the voltage divider output terminal according to the difference between the voltage divider signal of the voltage divider output terminal and the voltage of the third power supply terminal.

[0021] Optionally, the protection module includes: a comparison unit and an optocoupler control unit;

[0022] The first input terminal of the comparison unit is connected to the voltage divider output terminal of the voltage divider module, the second input terminal of the comparison unit is connected to the third power supply terminal, the output terminal of the comparison unit is connected to the second power supply terminal and the first terminal of the optocoupler control unit, the second and third terminals of the optocoupler control unit are connected to the ground terminal, and the fourth terminal of the optocoupler control unit is connected to the voltage divider output terminal of the voltage divider module. The comparison unit is used to output a level signal based on the difference between the voltage divider signal at the voltage divider output terminal and the voltage at the third power supply terminal. The optocoupler control unit is used to control the voltage at the voltage divider output terminal based on the level signal.

[0023] Optionally, the comparison unit includes a comparator, a first resistor, and a second resistor;

[0024] The first input terminal of the comparator is connected to the output terminal of the voltage divider module, the second input terminal of the comparator is connected to the first end of the first resistor, the second end of the first resistor is connected to the third power supply terminal, the output terminal of the comparator is connected to the first end of the second resistor and the first end of the optocoupler control unit, and the second end of the second resistor is connected to the second power supply terminal.

[0025] According to another aspect of the present invention, an AC charging pile is also provided, including the detection circuit described in any embodiment of the present invention.

[0026] The technical solution of this embodiment uses a voltage divider module and a control module in the detection circuit. When a short circuit fault occurs in the charging gun under test, the current flowing through the short circuit point is limited by the resistor in the voltage divider module, preventing overheating, and the voltage divider signal at the output terminal is pulled high. The control module compares the voltage divider signal at the output terminal with a preset threshold voltage. If the voltage divider signal at the output terminal is greater than the preset threshold voltage, a short circuit fault is determined to have occurred. The technical solution of this embodiment solves the problem of poor reliability in short circuit fault detection of charging guns, and can detect short circuit faults in advance when charging is not in progress, reducing charging safety risks.

[0027] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a detection circuit provided in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of another detection circuit provided in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of another detection circuit provided in this embodiment of the present invention;

[0032] Figure 4 This is a circuit diagram of a detection circuit provided in an embodiment of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] Figure 1 This is a schematic diagram of a detection circuit structure provided by an embodiment of the present invention. This embodiment is applicable to the scenario of short-circuit fault detection in electric vehicle charging guns. Figure 1 As shown, the detection circuit includes:

[0036] The first detection terminal A1 is used to connect to the first pole of the charging gun under test.

[0037] The second detection terminal A2 is used to connect to the second pole of the charging gun under test; the first detection terminal A1 and the second detection terminal A2 are open circuits to each other.

[0038] Voltage divider module 101 is connected between the first power supply terminal V1 and the ground terminal GND; the first detection terminal A1 is connected in series between the first power supply terminal V1 and the voltage divider output terminal of voltage divider module 101; the second detection terminal A2 is connected in series between the first power supply terminal V1 and the voltage divider output terminal; voltage divider module 101 is used to divide the voltage of the first power supply terminal V1 according to the electrical signal between the first detection terminal A1 and the second detection terminal A2.

[0039] The control module 102 is connected to the voltage divider output terminal of the voltage divider module 101. The control module 102 is used to determine the fault status of the charging gun under test based on the difference between the voltage divider signal at the voltage divider output terminal and the preset threshold voltage.

[0040] The first detection terminal A1 is connected to the first pole of the charging gun under test, and the second detection terminal A2 is connected to the second pole of the charging gun under test. The first pole of the charging gun under test can be the live wire output terminal, and the second pole can be the neutral wire output terminal. Under normal circumstances, the live and neutral wires of the charging gun under test are open circuits; therefore, the first detection terminal A1 and the second detection terminal A2 are open circuits to each other, i.e., not directly connected. When a short circuit fault occurs in the charging gun under test, the first detection terminal A1 and the second detection terminal A2 are also short-circuited. The first power supply terminal V1 is used to transmit DC voltage, for example, 12V. The voltage divider module 101 is connected between the first power supply terminal V1 and the ground terminal GND. The voltage divider module 101 includes at least two voltage divider networks, and can generate a divided voltage based on the at least two voltage divider networks, which is transmitted to the control module 102 through the divided voltage output terminal.

[0041] The control module 102 can be a microcontroller or a programmable logic controller. The control module 102 internally stores or sets a preset threshold voltage. The control module 102 can compare the voltage divider signal at the voltage divider output terminal with the preset threshold voltage, and determine the fault state of the charging gun under test based on the difference between the two. For example, if the voltage divider signal at the voltage divider output terminal is greater than the preset threshold voltage, the control module 102 determines that the charging gun under test has a short circuit fault and prohibits the charging gun from charging the device under test. For example, it can be set that when the voltage divider signal at the voltage divider output terminal is less than or equal to the preset threshold voltage, the control module 102 determines that there is no short circuit fault between the first and second poles of the charging gun under test, and in this case, the charging gun can charge the device under test normally.

[0042] Specifically, when the charging gun under test is normal and has no short-circuit fault, the first and second terminals of the charging gun under test are open. The first detection terminal A1 and the second detection terminal A2 are respectively connected to the first and second terminals of the charging gun under test, therefore the first detection terminal A1 and the second detection terminal A2 are also open. The voltage divider signal at the voltage divider output terminal of the voltage divider module 101 is less than or equal to the preset threshold voltage. The control module 102 determines that the charging gun under test has no short-circuit fault, and the charging gun can charge the device under test normally. When the charging gun under test has a short-circuit fault, the first detection terminal A1 and the second detection terminal A2 are respectively connected to the first and second terminals of the charging gun under test, which is equivalent to short-circuiting the first detection terminal A1 and the second detection terminal A2 together through the charging gun under test. The voltage divider signal at the voltage divider output terminal of the voltage divider module 101 will be pulled high. When the voltage divider signal at the voltage divider output terminal of the voltage divider module 101 is greater than the preset threshold voltage, the control module 102 determines that the charging gun under test has a short-circuit fault and prohibits the charging gun from charging the device under test.

[0043] The technical solution of this embodiment uses a voltage divider module and a control module in the detection circuit. When a short circuit fault occurs in the charging gun under test, the current flowing through the short circuit point is limited by the resistor in the voltage divider module, preventing overheating, and the voltage divider signal at the output terminal is pulled high. The control module compares the voltage divider signal at the output terminal with a preset threshold voltage. If the voltage divider signal at the output terminal is greater than the preset threshold voltage, a short circuit fault is determined to have occurred. The technical solution of this embodiment solves the problem of poor reliability in short circuit fault detection of charging guns, and can detect short circuit faults in advance when charging is not in progress, reducing charging safety risks.

[0044] Figure 2 This is a schematic diagram of another detection circuit provided in an embodiment of the present invention, as shown below. Figure 2 As shown, in some optional embodiments of this utility model, the detection circuit further includes a voltage follower module 103 and a voltage regulator module 104.

[0045] The first terminal of the voltage follower module 103 is connected to the voltage divider output terminal of the voltage divider module 101, the second terminal of the voltage follower module 101 is connected to the first terminal of the control module 102 and the voltage regulator module 104, the second terminal of the voltage regulator module 104 is connected to the second power supply terminal V2, and the third terminal of the voltage regulator module 104 is connected to the ground terminal GND.

[0046] The voltage follower module 103 may include an operational amplifier. The operational amplifier can be a voltage follower. The high input impedance of the voltage follower ensures that the current drawn from the voltage divider output is minimal, having almost no impact on the original voltage divider signal. The voltage follower module 103 provides buffer isolation between the voltage divider output signal of the voltage divider module 101 and the control module 102, reducing mutual interference. The voltage follower module 103 ensures that the voltage signal received by the control module 102 is the same as the voltage divider output signal of the voltage divider module 101. The second power supply terminal V2 is used to transmit DC voltage, for example, 3.3V. The voltage regulator module 104 can be a Zener diode. The voltage regulator module 104 maintains a constant output voltage from the voltage follower module 103.

[0047] Specifically, the voltage follower module 103 can read the voltage divider signal from the voltage divider output terminal and generate an identical voltage at its output terminal. The voltage regulator module 104 can provide a constant operating voltage to the voltage follower module 103, ensuring the stability of its amplifier's bias, gain, and other parameters, and performing the following function. The control module 102 compares the received voltage divider signal from the voltage follower module 103 with a preset threshold voltage to determine the charging gun's fault status.

[0048] In some optional embodiments of this utility model, the voltage divider module 101 includes: a first voltage divider network 1011; a first end of the first voltage divider network 1011 is connected to the ground terminal GND, and a second end of the first voltage divider network 1011 is connected to the control module 102.

[0049] The first terminal of the first voltage divider network 1011 is connected to the ground terminal GND, and its second terminal can be connected to the control module 102 through the voltage follower module 103. In the event of a short circuit fault, the voltage divider signal at the output terminal can be the voltage divider signal of the first voltage divider network 1011 and other voltage divider networks.

[0050] In some optional embodiments of this utility model, the voltage divider module 101 further includes a second voltage divider network 1012; a first end of the second voltage divider network 1012 is connected to a first power supply terminal V1, and a second end of the second voltage divider network 1012 is connected to a first detection terminal A1; and / or,

[0051] The third voltage divider network 1013; the first end of the third voltage divider network 1013 is connected to the second detection terminal A2, and the second end of the third voltage divider network 1013 is connected to the first end of the first voltage divider network 1011.

[0052] The second voltage divider network 1012 and the third voltage divider network 1013 may include one resistor or multiple resistors. The first terminal of the second voltage divider network 1012 is connected to the first power supply terminal V1, and its second terminal is connected to the first detection terminal A1. The first terminal of the third voltage divider network 1013 is connected to the second detection terminal A2, and its second terminal is connected to the first terminal of the first voltage divider network 1011. Only one of the second voltage divider network 1012 or the third voltage divider network 1013 may be used, or both may be used simultaneously.

[0053] Specifically, when only the second voltage divider network 1012 is configured, the first detection terminal A1 and the second detection terminal A2 are connected to the first and second terminals of the charging gun under test, respectively. If a short circuit fault occurs in the charging gun under test, the voltage divider output signal is the voltage divider signal of the first voltage divider network 1011 and the second voltage divider network 1012. When only the third voltage divider network 1013 is configured, the first detection terminal A1 and the second detection terminal A2 are connected to the first and second terminals of the charging gun under test, respectively. If a short circuit fault occurs in the charging gun under test, the voltage divider output signal is the voltage divider signal of the first voltage divider network 1011 and the third voltage divider network 1012. When both the second voltage divider network 1012 and the third voltage divider network 1013 are configured, the first detection terminal A1 and the second detection terminal A2 are connected to the first and second terminals of the charging gun under test, respectively. If the charging gun under test has a short circuit fault, the voltage divider signal at the voltage divider output terminal is the voltage divider signal of the first voltage divider network 1011, the second voltage divider network 1012, and the third voltage divider network 1013.

[0054] Figure 3 This is a schematic diagram of another detection circuit provided in an embodiment of the present invention, as shown below. Figure 3 As shown, in some optional embodiments of this utility model, the detection circuit further includes: at least one switching module 105; a first terminal of the at least one switching module 105 is connected to a second terminal of the second voltage divider network 1012, and a second terminal of the at least one switching module 105 is connected to a first detection terminal A1; and / or,

[0055] At least one switch module 105 has its first end connected to the second detection terminal A2, and at least one switch module 105 has its second end connected to the first end of the third voltage divider network 1013.

[0056] By controlling the on / off state of at least one switch module 105, the short-circuit detection of the charging gun under test can be controlled by the detection circuit. When only one switch module 105 is provided, the switch module 105 can be located between the second voltage divider network 1012 and the first detection terminal A1, or the switch module 105 can be located between the second detection terminal A2 and the first terminal of the third voltage divider network 1013. When two switch modules are provided, both of the above-mentioned configurations of the switch module 105 are included. By providing at least one switch module 105, the switch module 105 can be disconnected when continuous detection is not required or when a short-circuit fault is detected, thus avoiding continuous current surges that could damage the circuit.

[0057] In some optional embodiments of this utility model, reference continues to be made. Figure 3 At least one switching module 105 includes a first relay J1, a first terminal of which is connected to a second terminal of a second voltage divider network 1012, and a second terminal of which is connected to a first detection terminal A1; and / or,

[0058] At least one switching module 105 includes a second relay J2, the first end of which is connected to a second detection terminal A2, and the second end of which is connected to the first end of a third voltage divider network 1013.

[0059] The switch module 105 can be a relay. When only one switch module 105 is provided, it may include a first relay J1. The first relay J1 is located between the second voltage divider network 1012 and the first detection terminal A1. When only one switch module 105 is provided, it may also include a second relay J2, which is located between the second detection terminal A2 and the third voltage divider network 1013. When two switch modules 105 are provided, they may include a first relay J1 and a second relay J2, and the arrangement of the two relays may vary. By setting the first relay J1 and / or the second relay J2, closing the first relay J1 and / or the second relay J2 can initiate short-circuit fault detection of the charging gun under test.

[0060] In some optional embodiments of this utility model, reference continues to be made. Figure 3 The detection circuit also includes: a protection module 106, the first and second terminals of the protection module 106 are connected to the voltage divider output terminal of the voltage divider module 101, the third terminal of the protection module 106 is connected to the third power supply terminal V3, the fourth terminal of the protection module 105 is connected to the second power supply terminal V2, and the fifth and sixth terminals of the protection module 106 are connected to the ground terminal GND. The protection module is used to control the voltage of the voltage divider output terminal according to the difference between the voltage divider signal of the voltage divider output terminal and the voltage of the third power supply terminal V3.

[0061] The third power supply terminal V3 is used to transmit DC voltage, such as 5V. The protection module 106 compares the voltage at the third power supply terminal V3 with the voltage divider signal at the voltage divider output terminal of the voltage divider module 101 to determine whether protection of the voltage divider output signal is required. When the voltage divider signal at the voltage divider output terminal is greater than the voltage at the third power supply terminal V3, the protection module 106 can connect the third and fifth terminals to pull the voltage divider signal low. The protection module 106 can protect the voltage divider signal at the voltage divider output terminal through a comparator and an optocoupler. By setting up the protection module 106, the safety of the charging pile can be protected, preventing damage due to various complex charging environments and improving the reliability of short-circuit detection.

[0062] In some optional embodiments of this utility model, reference continues to be made. Figure 3 The protection module 106 includes a comparison unit 1061 and an optocoupler control unit 1062.

[0063] The first input terminal of the comparator unit 1061 is connected to the voltage divider output terminal of the voltage divider module 101. The second input terminal of the comparator unit 1061 is connected to the third power supply terminal V3. The output terminal of the comparator unit 1061 is connected to the second power supply terminal V2 and the first terminal of the optocoupler control unit 1062. The second and third terminals of the optocoupler control unit 1062 are connected to the ground terminal GND. The fourth terminal of the optocoupler control unit 1062 is connected to the voltage divider output terminal of the voltage divider module 101. The comparator unit 1061 is used to output a level signal based on the difference between the voltage divider signal at the voltage divider output terminal and the voltage at the third power supply terminal V3. The optocoupler control unit 1062 is used to control the voltage at the voltage divider output terminal based on the level signal.

[0064] The comparison unit 1061 can be a comparator. The optocoupler control unit 1062 can be an optocoupler. The optocoupler drives a light-emitting diode to emit light through an input electrical signal. The light passes through an isolation channel and illuminates a photosensitive device. The photosensitive device changes its conduction state according to the light intensity, generating an output electrical signal. The comparison unit 1061 compares its first input terminal with its second input terminal and outputs a high-level signal or a low-level signal. The first terminal of the optocoupler control unit 1062 is connected to the output terminal of the comparison unit 1061. Based on the high-level or low-level signal from the comparison unit 1061, the control unit controls whether the third and fourth terminals of the optocoupler control unit 1062 are turned on, thereby controlling the voltage divider signal at the voltage divider output terminal.

[0065] Specifically, if the voltage divider signal at the output terminal is greater than the voltage at the third power supply terminal V3, the comparator unit 1061 outputs a high-level signal. The third and fourth terminals of the optocoupler control unit 1062 are turned on, pulling the voltage divider signal at the output terminal low, thus protecting the circuit from damage. If the voltage divider signal at the output terminal is less than or equal to the voltage at the third power supply terminal V3, the comparator unit 1061 outputs a low-level signal. The third and fourth terminals of the optocoupler control unit 1062 are not turned on.

[0066] In some optional embodiments of this utility model, reference continues to be made. Figure 3 The comparison unit 1061 includes a comparator COMP, a first resistor R1, and a second resistor R2.

[0067] The first input terminal of comparator COMP is connected to the output terminal of voltage divider module 101. The second input terminal of comparator COMP is connected to the first terminal of first resistor R1. The second terminal of first resistor R1 is connected to the third power supply terminal V3. The output terminal of comparator COMP is connected to the first terminal of second resistor R2 and the first terminal of optocoupler control unit 1062. The second terminal of second resistor R2 is connected to the second power supply terminal V2.

[0068] The comparator COMP compares the voltage divider signal at the voltage divider output terminal with the voltage at the third power supply terminal V3, and outputs a high-level signal or a low-level signal. The output signal of the comparator COMP directly drives the optocoupler control unit 1062, controlling whether the light-emitting diode of the optocoupler control unit 1062 emits light, thereby controlling whether the fourth terminal and the third terminal of the optocoupler control unit 1062 are connected.

[0069] Specifically, when the voltage divider output signal is greater than the voltage of the third power supply terminal V3, the comparator COMP outputs a high level, the LED of the optocoupler control unit 1062 lights up, and the fourth terminal of the optocoupler control unit 1062 is de-conductive from the third terminal, thus pulling the voltage divider output signal low. When the voltage divider output signal is less than or equal to the voltage of the third power supply terminal V3, the comparator COMP outputs a low level, the LED of the optocoupler control unit 1062 does not light up, and the third and fourth terminals of the optocoupler control unit 1062 are not conductive.

[0070] Figure 4 This is a circuit diagram of a detection circuit provided in an embodiment of the present invention, as shown below. Figure 4As shown, D3 and D4 are diodes. The third resistor R3 is the voltage divider resistor of the second voltage divider network 1012, and the fourth resistor R4 is the voltage divider resistor of the third voltage divider network 1013. Only one of the third resistor R3 and the fourth resistor R4 can be set, or both can be set simultaneously. The fifth resistor R5 is the voltage divider resistor of the first voltage divider network 1011. The first terminal of the sixth resistor R6 is connected to the output terminal of the voltage follower U1, and the second terminal of the sixth resistor R6 is connected to the first terminal of the first capacitor C1, the first terminal of the control module 102, and the first terminal of the voltage regulator module 105. The second terminal of the first capacitor C1 is connected to the ground terminal GND. The voltage regulator module 105 can be a Zener diode, or it can include a first diode D1 and a second diode D2. The working principle of this utility model is as follows: When short-circuit detection begins, the first detection terminal A1 and the second detection terminal A2 are connected to the first and second terminals of the charging gun under test, respectively. At least one first relay J1 and / or at least one second relay J2 of the switching module 105 are closed. If the voltage divider output signal is greater than the preset threshold voltage, the control module 102 determines that the charging gun under test has a short circuit fault and prohibits the charging gun from charging the device under test. If the voltage divider output signal is less than or equal to the preset threshold voltage, the control module 102 determines that there is no short circuit fault between the first and second poles of the charging gun under test, and the charging gun can charge the device under test normally. When the voltage divider output signal of the voltage divider module 101 is higher than the clamping voltage of the Zener diode D5, it is clamped to the voltage level of the Zener diode D5. If the comparator COMP outputs a low level, the fourth and third terminals of the optocoupler US1 are not conducting. If the comparator COMP outputs a high level, the fourth and third terminals of the optocoupler US1 are conducting, and the voltage divider output signal is directly pulled down to the ground terminal GND, protecting the circuit from damage. This achieves reliable detection of short circuit faults while protecting itself from damage.

[0071] The AC charging pile provided in this embodiment of the present invention may include the detection circuit provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the detection circuit.

[0072] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0073] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A detection circuit, characterized by, include: The first detection terminal is used to connect to the first pole of the charging gun under test; The second detection terminal is used to connect to the second pole of the charging gun under test; The first detection terminal and the second detection terminal are open-circuited to each other; A voltage divider module is connected between a first power supply terminal and a ground terminal; a first detection terminal is connected in series between the first power supply terminal and the voltage divider output terminal of the voltage divider module; a second detection terminal is connected in series between the first power supply terminal and the voltage divider output terminal; the voltage divider module is used to divide the voltage of the first power supply terminal according to the electrical signal between the first detection terminal and the second detection terminal. A control module is connected to the voltage divider output terminal of the voltage divider module. The control module is used to determine the fault state of the charging gun under test based on the difference between the voltage divider signal at the voltage divider output terminal and the preset threshold voltage.

2. The detection circuit of claim 1, wherein, The detection circuit also includes: a voltage follower module and a voltage regulator module; The first terminal of the voltage follower module is connected to the voltage divider output terminal of the voltage divider module, the second terminal of the voltage follower module is connected to the first terminal of the control module and the voltage regulator module, the second terminal of the voltage regulator module is connected to the second power supply terminal, and the third terminal of the voltage regulator module is connected to the ground terminal.

3. The detection circuit according to claim 1 or 2, characterized in that, The voltage divider module includes: a first voltage divider network; a first end of the first voltage divider network is connected to the grounding terminal, and a second end of the first voltage divider network is connected to the control module.

4. The detection circuit of claim 3, wherein, The voltage divider module further includes a second voltage divider network; a first end of the second voltage divider network is connected to a first power supply terminal, and a second end of the second voltage divider network is connected to the first detection terminal; and / or... A third voltage divider network; the first end of the third voltage divider network is connected to the second detection terminal, and the second end of the third voltage divider network is connected to the first end of the first voltage divider network.

5. The detection circuit of claim 4, wherein, The detection circuit further includes: at least one switching module; a first terminal of the at least one switching module is connected to a second terminal of the second voltage divider network, and a second terminal of the at least one switching module is connected to the first detection terminal; and / or, The first end of the at least one switching module is connected to the second detection terminal, and the second end of the at least one switching module is connected to the first end of the third voltage divider network.

6. The detection circuit of claim 5, wherein, The at least one switching module includes a first relay, a first terminal of which is connected to a second terminal of the second voltage divider network, and a second terminal of which is connected to the first detection terminal; and / or The at least one switching module includes a second relay, the first end of which is connected to the second detection terminal, and the second end of which is connected to the first end of the third voltage divider network.

7. The detection circuit according to claim 1, characterized in that, The detection circuit further includes: a protection module, wherein the first and second terminals of the protection module are connected to the voltage divider output terminal of the voltage divider module, the third terminal of the protection module is connected to the third power supply terminal, the fourth terminal of the protection module is connected to the second power supply terminal, and the fifth and sixth terminals of the protection module are connected to the ground terminal; the protection module is used to control the voltage of the voltage divider output terminal according to the difference between the voltage divider signal of the voltage divider output terminal and the voltage of the third power supply terminal.

8. The detection circuit according to claim 7, characterized in that, The protection module includes: a comparison unit and an optocoupler control unit; The first input terminal of the comparison unit is connected to the voltage divider output terminal of the voltage divider module, the second input terminal of the comparison unit is connected to the third power supply terminal, the output terminal of the comparison unit is connected to the second power supply terminal and the first terminal of the optocoupler control unit, the second and third terminals of the optocoupler control unit are connected to the ground terminal, and the fourth terminal of the optocoupler control unit is connected to the voltage divider output terminal of the voltage divider module. The comparison unit is used to output a level signal based on the difference between the voltage divider signal at the voltage divider output terminal and the voltage at the third power supply terminal. The optocoupler control unit is used to control the voltage at the voltage divider output terminal based on the level signal.

9. The detection circuit according to claim 8, characterized in that, The comparison unit includes a comparator, a first resistor, and a second resistor; The first input terminal of the comparator is connected to the output terminal of the voltage divider module, the second input terminal of the comparator is connected to the first end of the first resistor, the second end of the first resistor is connected to the third power supply terminal, the output terminal of the comparator is connected to the first end of the second resistor and the first end of the optocoupler control unit, and the second end of the second resistor is connected to the second power supply terminal.

10. An AC charging pile, characterized in that, Includes the detection circuit described in any one of claims 1-9.

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