Leakage current protection detection circuits, circuit breakers and electronic equipment

Abstract

This invention discloses a leakage current protection detection circuit, a circuit breaker, and an electronic device. The leakage current protection detection circuit includes a current acquisition unit, a leakage current protection unit, a leakage current tripping unit, a leakage current protection action detection unit, and a main control unit. This invention acquires the leakage current of the circuit under test through the current acquisition unit and detects the leakage current value through the leakage current protection unit. When the leakage current exceeds a preset current threshold, the leakage current tripping unit is controlled to perform a leakage current protection action. This invention incorporates a leakage current protection action detection unit within the leakage current protection circuit. This detection unit effectively isolates the leakage current protection unit from the main control unit and can accurately detect whether the leakage current tripping unit has performed a leakage current protection action.

Description

Technical Field

[0001] This invention relates to the field of low-voltage electrical appliances, and more particularly to a leakage current protection detection circuit, circuit breaker, and electronic equipment. Background Technology

[0002] Intelligent residual current circuit breakers with leakage current reclosing function have become the mainstream product in today's power systems. In order to ensure the safety and stability of leakage current operation, this type of residual current circuit breaker generally still uses a dedicated residual current protection chip to realize the leakage current protection function.

[0003] However, this type of circuit breaker is difficult to distinguish between leakage protection and other tripping situations. Generally, it can only be reclosed when leakage tripping occurs. Other manual tripping, short circuit protection, overload protection, etc., should not be reclosed.

[0004] Therefore, there is an urgent need for a leakage current protection detection solution that can accurately determine whether a leakage current protection circuit breaker has performed leakage current protection action. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides a leakage current protection detection circuit, a circuit breaker, and an electronic device, with the specific solution as follows:

[0006] In a first aspect, embodiments of this application provide a leakage current protection detection circuit, which includes: a current acquisition unit, a leakage current protection unit, a leakage current tripping unit, a leakage current protection action detection unit, and a main control unit;

[0007] The current acquisition unit is installed in the circuit to be tested, and the current acquisition unit is used to acquire the leakage current of the circuit to be tested;

[0008] The first input terminal of the leakage current protection unit is connected to the output terminal of the current acquisition unit, and the second input terminal of the leakage current protection unit is used to connect to the mains power.

[0009] The output terminal of the leakage current protection unit is connected to the control terminal of the leakage current tripping unit. The leakage current protection unit is used to send a tripping control signal to the leakage current tripping unit when the leakage current in the circuit is greater than a preset current threshold.

[0010] The input terminal of the leakage current protection action detection unit is connected to the output terminal of the leakage current protection unit, and the leakage current protection action detection unit is used to convert the trip control signal into a level signal;

[0011] The input terminal of the main control unit is connected to the output terminal of the leakage current protection action detection unit. The main control unit is used to determine whether the leakage current tripping unit performs leakage current protection action based on the level signal.

[0012] According to a specific embodiment of the present application, the current acquisition unit includes a zero-sequence current transformer;

[0013] The load side of the zero-sequence current transformer is connected in the path of the circuit to be tested, and the output side of the secondary coil of the zero-sequence current transformer is connected to the first input terminal of the leakage protection unit.

[0014] The zero-sequence current transformer is used to detect the current vector sum of the circuit to be tested and output the leakage current of the circuit to the leakage protection unit. The current value of the leakage current is determined by the current vector sum.

[0015] According to a specific embodiment of the present application, the leakage protection unit includes a power input branch, a first full-wave rectifier branch, a trip control branch, and a dedicated leakage protection chip.

[0016] The power input branch includes a first terminal, a second terminal, and a varistor. The first terminal and the second terminal serve as the second input terminals of the leakage protection unit. The first terminal is used to connect to the mains live wire and the first terminal is used to connect to the mains neutral wire. The varistor is connected in parallel between the first terminal and the second terminal.

[0017] The first terminal is connected to one input terminal of the first full-wave rectifier branch via the leakage current trip unit, and the second terminal is connected to the other input terminal of the first full-wave rectifier branch;

[0018] The positive output terminal of the first full-wave rectifier branch is connected to the first control terminal of the trip control branch, and the negative output terminal of the first full-wave rectifier branch is connected to the second control terminal of the trip control branch.

[0019] The second control terminal of the trip control branch is also connected to the trip control signal output terminal of the dedicated leakage protection chip;

[0020] The leakage signal detection terminal of the dedicated leakage protection chip is connected to the output terminal of the current acquisition unit as the first input terminal of the leakage protection unit. The dedicated leakage protection chip is used to output the trip control signal through the trip control signal output terminal when the leakage current of the circuit is detected to be greater than the preset current threshold.

[0021] According to a specific embodiment of the present application, the leakage protection unit further includes a power supply voltage regulation branch, which includes a Zener diode, a current limiting resistor, and an electrolytic capacitor.

[0022] The negative terminal of the Zener diode is connected to the power input terminal of the dedicated leakage protection chip, and the positive terminal of the Zener diode is grounded.

[0023] The negative terminal of the Zener diode is also connected to the positive output terminal of the full-wave rectifier branch through the current-limiting resistor;

[0024] The electrolytic capacitor is connected in parallel between the positive and negative terminals of the Zener diode.

[0025] According to a specific embodiment of this application, the tripping control branch includes a thyristor and a filter capacitor;

[0026] The anode of the thyristor is connected to the positive output terminal of the full-wave rectifier branch as the first control terminal of the trip control branch.

[0027] The cathode of the thyristor serves as the second control terminal of the trip control branch, and is connected to the negative output terminal of the full-wave rectifier branch and the trip control signal output terminal of the dedicated leakage protection chip, respectively.

[0028] One end of the filter capacitor is connected to the trip control signal output terminal of the dedicated leakage protection chip, and the other end of the filter capacitor is grounded.

[0029] According to a specific embodiment of the present application, the leakage current tripping unit includes a leakage current tripping device;

[0030] The switch control terminal of the residual current device is connected to the mains power. When the residual current device receives the trip control signal, it connects to the mains power through the switch control terminal to perform the residual current protection action.

[0031] According to a specific embodiment of the present application, the leakage protection action detection unit includes a second full-wave rectifier branch, a signal amplification branch, and a comparison amplification branch;

[0032] The first and second input terminals of the second full-wave rectifier branch are connected in parallel to the two ends of the leakage current trip unit;

[0033] The negative input terminal of the signal amplification branch is connected to the negative output terminal of the second full-wave rectifier branch through a preset number of current-limiting resistors. The negative input terminal of the signal amplification branch is also connected to the output terminal of the signal amplification branch through a resistor.

[0034] The positive input terminal of the signal amplification branch is connected to the positive output terminal of the second full-wave rectifier branch through a preset number of current-limiting resistors, and the positive input terminal of the signal amplification branch is grounded.

[0035] The output terminal of the signal amplification branch is connected to the positive input terminal of the comparison amplification branch, and the negative input terminal of the comparison amplification branch is used to connect to the reference voltage signal.

[0036] The output of the comparison amplification branch is connected to the input of the main control unit.

[0037] According to a specific embodiment of this application, the main control unit determines whether the leakage current tripping unit performs leakage current protection action based on the level signal within a single cycle time.

[0038] If the level signal remains low for a single cycle, it is determined that the leakage current trip unit has not performed leakage current protection action.

[0039] If the level signal within a single cycle time has a preset number of rising edge signals, it is determined that the leakage current trip unit has performed leakage current protection action.

[0040] Secondly, embodiments of this application provide a circuit breaker, which includes the leakage current protection detection circuit described in the first aspect and any embodiment of the first aspect.

[0041] Thirdly, embodiments of this application provide an electronic device, which includes the circuit breaker described in the second aspect above.

[0042] This application provides a leakage current protection detection circuit, a circuit breaker, and an electronic device. The leakage current protection detection circuit includes: a current acquisition unit, a leakage current protection unit, a leakage current tripping unit, a leakage current protection action detection unit, and a main control unit. This invention acquires the leakage current of the circuit under test through the current acquisition unit and detects the leakage current value through the leakage current protection unit. When the leakage current exceeds a preset current threshold, the leakage current tripping unit is controlled to perform a leakage current protection action. This invention incorporates a leakage current protection action detection unit within the leakage current protection circuit. This detection unit effectively isolates the leakage current protection unit from the main control unit and can accurately detect whether the leakage current tripping unit has performed a leakage current protection action. Attached Figure Description

[0043] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope of protection of the present invention. In the various drawings, similar components are numbered similarly.

[0044] Figure 1 A schematic diagram of a leakage current protection detection circuit according to an embodiment of this application is shown.

[0045] Figure 2 A schematic diagram of the circuit structure of a leakage current protection unit of a leakage current protection detection circuit provided in an embodiment of this application is shown;

[0046] Figure 3 A schematic diagram of the circuit structure of the leakage current protection action detection unit of a leakage current protection detection circuit provided in this application is shown;

[0047] Figure 4 This illustration shows an example of the level signal output by the leakage protection action detection unit of a leakage protection detection circuit provided in this application embodiment. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] The components of the embodiments of the invention described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0050] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of the invention, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0051] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0052] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.

[0053] refer to Figure 1 This is a schematic diagram of a leakage current protection detection circuit provided in an embodiment of this application. The leakage current protection detection circuit provided in this embodiment of the application is as follows: Figure 1As shown, the leakage current protection detection circuit includes: a current acquisition unit, a leakage current protection unit, a leakage current tripping unit, a leakage current protection action detection unit, and a main control unit;

[0054] The current acquisition unit is installed in the circuit to be tested, and the current acquisition unit is used to acquire the leakage current of the circuit to be tested;

[0055] The first input terminal of the leakage current protection unit is connected to the output terminal of the current acquisition unit, and the second input terminal of the leakage current protection unit is used to connect to the mains power.

[0056] The output terminal of the leakage current protection unit is connected to the control terminal of the leakage current tripping unit. The leakage current protection unit is used to send a tripping control signal to the leakage current tripping unit when the leakage current in the circuit is greater than a preset current threshold.

[0057] The input terminal of the leakage current protection action detection unit is connected to the output terminal of the leakage current protection unit, and the leakage current protection action detection unit is used to convert the trip control signal into a level signal;

[0058] The input terminal of the main control unit is connected to the output terminal of the leakage current protection action detection unit. The main control unit is used to determine whether the leakage current tripping unit performs leakage current protection action based on the level signal.

[0059] In a specific embodiment, the circuit to be tested can be a mains circuit or any multiphase circuit that will generate leakage current. This embodiment does not limit the type of circuit to be tested and can be adaptively replaced according to the actual application scenario.

[0060] The leakage current protection detection circuit proposed in this embodiment can be used on all leakage current circuit breakers that use dedicated leakage current protection chips for leakage current protection.

[0061] The leakage current protection detection circuit proposed in this embodiment includes a leakage current protection part circuit and a leakage current protection action detection part circuit. The leakage current protection part circuit includes a current acquisition unit, a leakage current protection unit, and a leakage current tripping unit. The leakage current protection action detection part circuit includes a leakage current protection action detection unit and a main control unit.

[0062] Specifically, the current acquisition unit is used to acquire the leakage current signal on the circuit to be tested.

[0063] The leakage current protection unit determines whether a leakage current has occurred in the circuit under test based on the current value of the leakage current signal acquired by the current acquisition unit, and generates a corresponding trip control signal based on the leakage current detection result. The trip control signal is used to implement the leakage current protection function.

[0064] The leakage current tripping unit is used to receive the tripping control signal sent by the leakage current protection unit and to perform the corresponding tripping action in order to realize leakage current protection of the circuit under test.

[0065] The leakage current protection action detection unit is used to detect whether the leakage current tripping unit has executed the leakage current protection action and generate a corresponding level signal. The leakage current protection action detection unit is also used to achieve strong and weak current isolation between the main control circuit and the circuit under test.

[0066] The main control unit is used to receive the level signal sent by the leakage current protection action detection unit, identify whether the leakage current protection circuit has performed leakage current protection action based on the level signal, and send the identification result to the corresponding host computer device.

[0067] In practical applications, the main control unit is also used to communicate with a host computer device, which can be a local host or a cloud server. The host computer device can notify the user of the information that the circuit under test has leakage and the leakage trip unit has performed the tripping process via SMS or APP push.

[0068] According to a specific embodiment of the present application, the current acquisition unit includes a zero-sequence current transformer;

[0069] The load side of the zero-sequence current transformer is connected in the path of the circuit to be tested, and the output side of the secondary coil of the zero-sequence current transformer is connected to the first input terminal of the leakage protection unit.

[0070] The zero-sequence current transformer is used to detect the current vector sum of the circuit to be tested and output the leakage current of the circuit to the leakage protection unit. The current value of the leakage current is determined by the current vector sum.

[0071] Specifically, such as Figure 2 As shown, the current acquisition unit can be a zero-sequence current transformer.

[0072] This embodiment does not specifically limit the model and structure of the zero-sequence current transformer.

[0073] In a specific implementation, the circuit to be tested is connected to the circuit breaker device through the zero-sequence current transformer, so that the zero-sequence current transformer can obtain the current vector sum of the circuit to be tested.

[0074] The zero-sequence current transformer outputs a corresponding loop leakage current on the secondary coil side according to a fixed ratio of the current vector sum. When the current vector sum is zero, the current value of the loop leakage current is lower than a preset current threshold, indicating that there is no leakage current in the loop to be detected. When the current vector sum is not zero, the current value of the loop leakage current is greater than the preset current threshold, indicating that there is leakage current in the loop to be detected.

[0075] Specifically, the current threshold can be set to 0 or a very small current threshold. The setting of the current threshold can be adaptively replaced according to the detection accuracy of leakage current in the circuit to be detected in the actual application scenario.

[0076] The output side of the secondary coil of the zero-sequence current transformer is the output terminal of the circuit leakage current signal detected by the zero-sequence current transformer. The output side of the secondary coil is electrically connected to the first input terminal of the leakage protection unit. That is, the zero-sequence current transformer inputs the circuit leakage current to the leakage protection unit so that the leakage protection unit can detect whether the circuit under test has leakage and perform corresponding processing actions according to the leakage situation.

[0077] According to a specific embodiment of the present application, the leakage protection unit includes a power input branch, a first full-wave rectifier branch, a trip control branch, and a dedicated leakage protection chip.

[0078] The power input branch includes a first terminal, a second terminal, and a varistor. The first terminal and the second terminal serve as the second input terminals of the leakage protection unit. The first terminal is used to connect to the mains live wire and the first terminal is used to connect to the mains neutral wire. The varistor is connected in parallel between the first terminal and the second terminal.

[0079] The first terminal is connected to one input terminal of the first full-wave rectifier branch via the leakage current trip unit, and the second terminal is connected to the other input terminal of the first full-wave rectifier branch;

[0080] The positive output terminal of the first full-wave rectifier branch is connected to the first control terminal of the trip control branch, and the negative output terminal of the first full-wave rectifier branch is connected to the second control terminal of the trip control branch.

[0081] The second control terminal of the trip control branch is also connected to the trip control signal output terminal of the dedicated leakage protection chip;

[0082] The leakage signal detection terminal of the dedicated leakage protection chip is connected to the output terminal of the current acquisition unit as the first input terminal of the leakage protection unit. The dedicated leakage protection chip is used to output the trip control signal through the trip control signal output terminal when the leakage current of the circuit is detected to be greater than the preset current threshold.

[0083] In a specific embodiment, such as Figure 2 As shown, the power input branch includes a first terminal J1 connected to the mains live wire L and a second terminal J2 connected to the neutral wire N. A varistor RV1 is also connected in parallel between the first terminal J1 and the second terminal J2. The varistor changes its resistance value according to the magnitude of the voltage, and can play a role in transient voltage protection in the leakage current protection unit of this embodiment.

[0084] The first terminal J1 and the second terminal J2 of the voltage protection unit serve as the second input terminals, and the AC mains power connected to them can be 180V or 220V AC power.

[0085] It should be noted that the magnitude of the AC mains power can be adaptively replaced according to the actual application scenario. The AC mains power can also be replaced with other power supply devices for providing high voltage, which is not limited here.

[0086] The first full-wave rectifier branch is a full-bridge rectifier circuit, such as... Figure 2 As shown, the first full-wave rectifier circuit is a full-bridge rectifier circuit D1.

[0087] A leakage trip unit is connected in series between one input terminal of the full-bridge rectifier circuit D1 and terminal J1, and the other input terminal of the full-bridge rectifier circuit D1 is connected to terminal J2.

[0088] The first full-wave rectifier branch is used to perform full-wave rectification on the high-voltage mains power connected to the power input branch, ensuring that the leakage protection unit obtains a stable power supply current.

[0089] According to a specific embodiment of this application, the tripping control branch includes a thyristor and a filter capacitor;

[0090] The anode of the thyristor is connected to the positive output terminal of the full-wave rectifier branch as the first control terminal of the trip control branch.

[0091] The cathode of the thyristor serves as the second control terminal of the trip control branch, and is connected to the negative output terminal of the full-wave rectifier branch and the trip control signal output terminal of the dedicated leakage protection chip, respectively.

[0092] One end of the filter capacitor is connected to the trip control signal output terminal of the dedicated leakage protection chip, and the other end of the filter capacitor is grounded.

[0093] In a specific embodiment, the trip control branch is a thyristor D2 used to control the leakage current trip unit to perform the trip action. When the thyristor is turned on, it outputs a corresponding trip control signal to the leakage current trip unit so that the leakage current trip unit performs the corresponding trip action.

[0094] The anode of the thyristor D2 is connected to the positive output terminal of the full-bridge rectifier circuit D1, and the cathode of the thyristor D2 is connected to the negative output terminal of the full-bridge rectifier circuit D1. The second control terminal of the thyristor D2, i.e., the cathode of the thyristor, is also connected to the trip control signal output terminal OS of the dedicated leakage protection chip U3.

[0095] Specifically, the voltage signal at the first control terminal of thyristor D2, i.e., the anode of thyristor D2, remains stable. The voltage signal at the second control terminal of thyristor D2, i.e., the cathode of thyristor D2, varies with the trip control signal output by the trip control signal output terminal OS.

[0096] When the trip control signal output terminal OS outputs a trip control signal, the thyristor D2 is turned on.

[0097] Specifically, the trip control signal output terminal OS is also connected to the GND pin of the dedicated leakage protection chip through a filter capacitor C1. The filter capacitor C1 is used to ensure the stability and reliability of the trip control signal.

[0098] The dedicated leakage current detection chip U3 also includes an IN pin and a VR pin, which serve as the first input terminals of the leakage current protection unit and are electrically connected to the secondary coil side of the zero-inductance current transformer.

[0099] A sampling resistor R2 is connected in parallel between the IN pin and the VR pin. The sampling resistor R2 is used to convert the loop leakage current generated by the zero-inductance current transformer into a leakage voltage signal.

[0100] The dedicated leakage current detection chip U3 acquires the leakage current voltage signal through the IN pin and the VR pin, and detects whether a leakage current occurs in the circuit under test based on the voltage value of the leakage current voltage signal. When a leakage current occurs in the circuit under test, the dedicated leakage current detection chip U3 outputs a trip control signal through the trip control signal output terminal OS.

[0101] According to a specific embodiment of the present application, the leakage protection unit further includes a power supply voltage regulation branch, which includes a Zener diode, a current limiting resistor, and an electrolytic capacitor.

[0102] The negative terminal of the Zener diode is connected to the power input terminal of the dedicated leakage protection chip, and the positive terminal of the Zener diode is grounded.

[0103] The negative terminal of the Zener diode is also connected to the positive output terminal of the full-wave rectifier branch through the current-limiting resistor;

[0104] The electrolytic capacitor is connected in parallel between the positive and negative terminals of the Zener diode.

[0105] In a specific embodiment, the dedicated leakage current detection chip U3 also includes a power input pin VS.

[0106] The negative terminal of the Zener diode D3 is connected to the power input pin VS of the dedicated leakage protection chip U3, and the positive terminal of the Zener diode is connected to the power ground GND of the dedicated leakage protection chip U3. The Zener diode D3 is used to provide a stable voltage for the dedicated leakage protection chip U3.

[0107] The Zener diode D3 is connected to the positive output terminal of the full-bridge rectifier circuit D1 through the current-limiting resistor R1; the Zener diode D3 is also connected in parallel with an electrolytic capacitor C2, which is used to make the DC voltage generated by the Zener diode D3 more stable, and to provide a more stable operating power supply for the dedicated leakage protection chip U3.

[0108] According to a specific embodiment of the present application, the leakage current tripping unit includes a leakage current tripping device;

[0109] The switch control terminal of the residual current device is connected to the mains power. When the residual current device receives the trip control signal, it connects to the mains power through the switch control terminal to perform the residual current protection action.

[0110] In a specific embodiment, such as Figure 2 As shown, the switch control terminal of the leakage current trip unit L1 is connected to the mains power. When the leakage current trip unit receives a trip control signal, it controls the switch control terminal to close, so that the two ends of the leakage current trip unit L1 are connected to the mains power in parallel.

[0111] The residual current trip unit L1 starts working after being connected to the mains power, controlling the residual current circuit breaker to perform a tripping action.

[0112] According to a specific embodiment of the present application, the leakage current protection action detection unit includes a second full-wave rectifier branch, a signal amplification branch, and a comparison amplification branch;

[0113] The first and second input terminals of the second full-wave rectifier branch are connected in parallel to the two ends of the leakage current trip unit;

[0114] The negative input terminal of the signal amplification branch is connected to the negative output terminal of the second full-wave rectifier branch through a preset number of current-limiting resistors. The negative input terminal of the signal amplification branch is also connected to the output terminal of the signal amplification branch through a resistor.

[0115] The positive input terminal of the signal amplification branch is connected to the positive output terminal of the second full-wave rectifier branch through a preset number of current-limiting resistors, and the positive input terminal of the signal amplification branch is grounded.

[0116] The output terminal of the signal amplification branch is connected to the positive input terminal of the comparison amplification branch, and the negative input terminal of the comparison amplification branch is used to connect to the reference voltage signal.

[0117] The output of the comparison amplification branch is connected to the input of the main control unit.

[0118] In a specific embodiment, the circuit structure of the second full-wave rectifier branch can be similar to that of the first full-wave rectifier branch, or the circuit structure of the second full-wave rectifier branch can be different from that of the first full-wave rectifier branch, depending on the actual application scenario.

[0119] In this embodiment, the second full-wave rectifier branch is a full-bridge rectifier circuit D4, and the two input terminals of the second full-bridge rectifier circuit D4 are connected in parallel with the leakage current trip unit L1.

[0120] like Figure 3 As shown, the signal amplification branch includes an operational amplifier U1A that amplifies the trip control signal output by the leakage current protection unit.

[0121] In one example, the specific connection structure of the signal amplification branch can be as follows: the negative input terminal of the operational amplifier U1A is connected to the negative output terminal of the full-bridge rectifier circuit D4 through five series-connected current-limiting resistors R3, R4, R5, R6, and R7; the negative input terminal of the operational amplifier U1A is connected to the output terminal of the operational amplifier U1A through resistor R11; the positive input terminal of the operational amplifier U1A is connected to the positive output terminal of the full-bridge rectifier circuit D4 through three series-connected current-limiting resistors R8, R9, and R10; and the positive input terminal of the operational amplifier U1A is connected to the signal ground of the main control circuit.

[0122] The preset number of current-limiting resistors between the negative input terminal of the signal amplification branch and the full-bridge rectifier circuit, as well as the preset number of current-limiting resistors between the positive input terminal of the signal amplification branch and the positive output terminal of the full-bridge rectifier circuit D4, can be determined according to the actual application scenario. It should be noted that the preset number should be large enough to ensure that the leakage protection detection unit can effectively isolate the influence of strong and weak currents, reducing excessive leakage current caused by high voltage differences between strong and weak currents.

[0123] After amplifying the trip control signal, the signal amplification branch inputs the amplified trip control signal into the comparison amplification branch, so that the comparison amplification branch can compare it with a preset reference voltage signal.

[0124] In one example, the comparison amplification branch includes operational amplifier U1B, the positive input terminal of which is connected to the output terminal of operational amplifier U1A via a series resistor R14; the negative input terminal of operational amplifier U1B is connected to a reference voltage signal; the reference voltage signal is obtained by voltage divider resistors R12 and R13; one end of voltage divider resistor R12 is connected to VDD of the main control unit; the other end of voltage divider resistor R12 is connected to one end of voltage divider resistor R13 and the negative input terminal of operational amplifier U1B; the other end of voltage divider resistor R13 is connected to the signal ground of the main control circuit; the output terminal of operational amplifier U1B is connected to the GPIO signal acquisition port of the main control unit via resistor R15.

[0125] The comparison amplification branch compares the amplified trip control signal with the reference voltage signal to obtain the corresponding level signal.

[0126] Specifically, when the trip control signal is less than the reference voltage signal, the comparison amplification branch outputs a low-level signal; when the trip control signal is greater than or equal to the reference voltage signal, the comparison amplification branch outputs a high-level signal.

[0127] Specifically, the operating power supply for both operational amplifier U1A and operational amplifier U1B is provided by the VDD terminal and signal ground terminal of the main control unit.

[0128] According to a specific embodiment of this application, the main control unit determines whether the leakage current tripping unit performs leakage current protection action based on the level signal within a single cycle time.

[0129] If the level signal remains low for a single cycle, it is determined that the leakage current trip unit has not performed leakage current protection action.

[0130] If the level signal within a single cycle time has a preset number of rising edge signals, it is determined that the leakage current trip unit has performed leakage current protection action.

[0131] In a specific embodiment, such as Figure 3 As shown, the main control unit includes a main control chip U2 that receives and determines whether the leakage current tripping unit performs leakage current protection action.

[0132] The signal detection GPIO port of the main control chip U2 is connected to the output terminal of the comparator amplifier branch through resistor R15. The main control chip U2 detects whether the circuit under test has experienced leakage protection action based on the high and low level signal of the signal detection GPIO port within a fixed single cycle time.

[0133] Specifically, the duration of a single cycle can be set to 16.6ms or 20ms, and the duration of a single cycle can also be adaptively replaced according to the actual application scenario. A single cycle refers to the duration of one detection cycle.

[0134] If the level signal remains low for a single cycle, it is considered that the leakage current trip unit L1 has not performed leakage current protection.

[0135] If the level signal has N rising edges within a single cycle time, it is considered that the leakage current trip unit L1 has performed leakage protection action.

[0136] Specifically, the number of rising edge signals N can be 1 or 2 times, and the preset number of rising edge signals can be adaptively replaced according to the detection accuracy of the leakage current protection behavior detection unit.

[0137] like Figure 4 As shown, during the 0-40ms detection process, the main control unit determines that no leakage current has occurred in the circuit under test, and the leakage current trip unit does not perform leakage protection action. During the 40-80ms detection process, the main control unit determines that a leakage current has occurred in the circuit under test, and the leakage current trip unit has performed leakage protection action.

[0138] It is important to know that Figure 4 This is for illustrative purposes only; the detection process can be adapted to the actual application scenario.

[0139] In summary, the leakage current protection detection circuit proposed in this application can, while providing leakage current protection for the circuit under test, accurately determine through the leakage current protection behavior detection circuit that the circuit breaker trips due to leakage current in the circuit under test, thereby enabling faster resolution and restoration of operation of the circuit under test. Furthermore, by incorporating a resistor with a large resistance value in the leakage current protection behavior detection unit, excessive leakage current caused by high voltage differences between high and low voltage circuits can be reduced through isolation.

[0140] This application also provides a circuit breaker, which includes the leakage current protection detection circuit in the foregoing embodiments.

[0141] This application also provides an electronic device, which includes the circuit breaker from the foregoing embodiments.

[0142] The specific implementation process of the circuit breaker and electronic equipment mentioned in the above embodiments can be found in the specific implementation process of the above method embodiments, and will not be repeated here.

[0143] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that, as an alternative implementation, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0144] In addition, the functional modules or units in the various embodiments of the present invention can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0145] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a smartphone, personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0146] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A leakage current protection detection circuit, characterized in that, The leakage current protection detection circuit includes: a current acquisition unit, a leakage current protection unit, a leakage current tripping unit, a leakage current protection action detection unit, and a main control unit; The current acquisition unit is installed in the circuit to be tested, and the current acquisition unit is used to acquire the leakage current of the circuit to be tested; The first input terminal of the leakage current protection unit is connected to the output terminal of the current acquisition unit, and the second input terminal of the leakage current protection unit is used to connect to the mains power. The output terminal of the leakage current protection unit is connected to the control terminal of the leakage current tripping unit. The leakage current protection unit is used to send a tripping control signal to the leakage current tripping unit when the leakage current in the circuit is greater than a preset current threshold. The input terminal of the leakage current protection action detection unit is connected to the output terminal of the leakage current protection unit, and the leakage current protection action detection unit is used to convert the trip control signal into a level signal; The input terminal of the main control unit is connected to the output terminal of the leakage current protection action detection unit. The main control unit is used to determine whether the leakage current tripping unit performs leakage current protection action based on the level signal. The leakage current protection action detection unit is also used to realize the strong and weak current isolation between the main control unit and the circuit to be detected. The leakage current protection action detection unit includes a second full-wave rectifier branch, a signal amplification branch and a comparison amplification branch. The first and second input terminals of the second full-wave rectifier branch are connected in parallel to the two ends of the leakage current trip unit; The negative input terminal of the signal amplification branch is connected to the negative output terminal of the second full-wave rectifier branch through a preset number of current-limiting resistors. The negative input terminal of the signal amplification branch is also connected to the output terminal of the signal amplification branch through a resistor. The positive input terminal of the signal amplification branch is connected to the positive output terminal of the second full-wave rectifier branch through a preset number of current-limiting resistors, and the positive input terminal of the signal amplification branch is grounded. The output terminal of the signal amplification branch is connected to the positive input terminal of the comparison amplification branch, and the negative input terminal of the comparison amplification branch is used to connect to the reference voltage signal. The output of the comparison amplification branch is connected to the input of the main control unit.

2. The leakage current protection detection circuit according to claim 1, characterized in that, The current acquisition unit includes a zero-sequence current transformer; The load side of the zero-sequence current transformer is connected in the path of the circuit to be tested, and the output side of the secondary coil of the zero-sequence current transformer is connected to the first input terminal of the leakage protection unit. The zero-sequence current transformer is used to detect the current vector sum of the circuit to be tested and output the leakage current of the circuit to the leakage protection unit. The current value of the leakage current is determined by the current vector sum.

3. The leakage current protection detection circuit according to claim 1, characterized in that, The leakage protection unit includes a power input branch, a first full-wave rectifier branch, a trip control branch, and a dedicated leakage protection chip. The power input branch includes a first terminal, a second terminal, and a varistor. The first terminal and the second terminal serve as the second input terminals of the leakage protection unit. The first terminal is used to connect to the mains live wire, and the second terminal is used to connect to the mains neutral wire. The varistor is connected in parallel between the first terminal and the second terminal. The first terminal is connected to one input terminal of the first full-wave rectifier branch via the leakage current trip unit, and the second terminal is connected to the other input terminal of the first full-wave rectifier branch; The positive output terminal of the first full-wave rectifier branch is connected to the first control terminal of the trip control branch, and the negative output terminal of the first full-wave rectifier branch is connected to the second control terminal of the trip control branch. The second control terminal of the trip control branch is also connected to the trip control signal output terminal of the dedicated leakage protection chip; The leakage signal detection terminal of the dedicated leakage protection chip is connected to the output terminal of the current acquisition unit as the first input terminal of the leakage protection unit. The dedicated leakage protection chip is used to output the trip control signal through the trip control signal output terminal when the leakage current of the circuit is detected to be greater than the preset current threshold.

4. The leakage current protection detection circuit according to claim 3, characterized in that, The leakage protection unit also includes a power supply voltage regulation branch, which includes a Zener diode, a current limiting resistor, and an electrolytic capacitor. The negative terminal of the Zener diode is connected to the power input terminal of the dedicated leakage protection chip, and the positive terminal of the Zener diode is grounded. The negative terminal of the Zener diode is also connected to the positive output terminal of the first full-wave rectifier branch through the current-limiting resistor; The electrolytic capacitor is connected in parallel between the positive and negative terminals of the Zener diode.

5. The leakage current protection detection circuit according to claim 3, characterized in that, The trip control branch includes a thyristor and a filter capacitor; The anode of the thyristor is connected to the positive output terminal of the first full-wave rectifier branch as the first control terminal of the trip control branch. The cathode of the thyristor is connected to the negative output terminal of the first full-wave rectifier branch as the second control terminal of the trip control branch. The control electrode of the thyristor is connected to the tripping control signal output terminal of the dedicated leakage protection chip; One end of the filter capacitor is connected to the trip control signal output terminal of the dedicated leakage protection chip, and the other end of the filter capacitor is grounded.

6. The leakage current protection detection circuit according to claim 1, characterized in that, The leakage current tripping unit includes a leakage current tripping device; The switch control terminal of the residual current device is connected to the mains power. When the residual current device receives the trip control signal, it connects to the mains power through the switch control terminal to perform the residual current protection action.

7. The leakage current protection detection circuit according to claim 1, characterized in that, The main control unit determines whether the leakage current trip unit should perform leakage current protection based on the level signal within a single cycle time. If the level signal remains low for a single cycle, it is determined that the leakage current trip unit has not performed leakage current protection action. If the level signal within a single cycle time has a preset number of rising edge signals, it is determined that the leakage current trip unit has performed leakage current protection action.

8. A circuit breaker, characterized in that, The circuit breaker includes the leakage current protection detection circuit as described in any one of claims 1-7.

9. An electronic device, characterized in that, The electronic device includes the circuit breaker as described in claim 8.

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