Earth leakage protection circuit and device

Abstract

The invention provides an electric leakage protection circuit and device. The electric leakage protection circuit comprises a power supply circuit, an electric leakage detection circuit, a tripping circuit and a control circuit, the power supply circuit comprises a first L-phase power supply branch, a second L-phase power supply branch, a third L-phase power supply branch, an N-phase power supply branch, a rectification circuit and a test circuit. The first L-phase power supply branch is connected with the negative electrode of the diode VD2, and half-wave rectification is realized through the diode VD2; the second L-phase power supply branch is connected with the positive electrode of the diode VD5, and half-wave rectification is realized through the diode VD5; the third L-phase power supply branch is connected with the negative electrode and the positive electrode of a diode VD3 and the positive electrode of a diode VD6 respectively, full-wave rectification is achieved through the diode VD3 and the diode VD6, the third L-phase power supply branch is connected with the test circuit, and breaking of the third L-phase power supply branch is kept synchronous with opening and closing of the circuit breaker; the N-phase power supply branch is connected with the negative electrode and the positive electrode of the diode VD1 and the diode VD4, and full-wave rectification is achieved through the diode VD1 and the diode VD4.

Description

Technical Field

[0001] The invention relates to the field of low-voltage electrical appliances, and in particular to a leakage protection circuit and a device. Background Art

[0002] A residual current operated circuit breaker is a switch device that can close, carry and break the current under normal circuit conditions and close, carry and break the current under abnormal circuit conditions within a specified time. When users use a residual current operated circuit breaker for line terminal wiring operations, if the wiring is wrong, the product coil will burn, the integrated chip will be damaged, and the thyristor will explode, causing the product to fail.

[0003] That is to say, the residual current circuit breaker with overload and short-circuit protection function can provide overload and short-circuit protection for the line. In the three-phase four-wire rectifier circuit, the neutral line input terminal of the 3P+N residual current circuit breaker must be connected to the neutral line N, and not any of the three-phase lines. Once the neutral line N is not accurately connected to the neutral line input terminal, but any of the phase lines is connected to the neutral line input terminal, the circuit board of the residual current circuit breaker is easily damaged by overvoltage. In the existing leakage principle of the electronic component board, the power supply part adopts a three-phase four-wire bridge rectifier, which can achieve normal operation when any two poles are energized. When the product input and output lines are connected incorrectly (reverse wiring), if leakage is triggered at this time, the circuit board will continue to supply power, and the thyristor cannot pass zero (or is lower than the maintenance voltage), so that the coil cannot stop conducting and burns out. The reason is that the bridge rectifier circuit composed of three-phase four wires provides a continuous DC voltage that does not pass zero.

[0004] An existing leakage protection device, under the condition of three-phase three-wire connection, realizes zero voltage across the thyristor through half-wave rectification, effectively protecting the safety of the product. Figure 5 The simplified equivalent circuit diagram of the power supply circuit is shown in Figure 2. Figure 6 As shown, during three-phase half-wave rectification, the maximum voltage across the thyristor is 563V, the minimum is 3V, the effective value is 367V, and the voltage is approximately zero during the cycle.

[0005] However, Figure 7 and Figure 8 As shown in the figure, under the condition of three-phase four-wire connection, half-wave rectification is adopted, the maximum voltage across the thyristor is 563V, the minimum is 59V, the effective value is 390V, and the voltage still does not reach zero during the cycle. Therefore, under the condition of three-phase four-wire connection, the half-wave rectification method cannot achieve voltage zero crossing.

[0006] like Fig. 9 and Fig.10 As shown, under the three-phase four-wire connection conditions, full-bridge rectification is adopted, the voltage peak value of both ends of the thyristor is 563V, the minimum value is 502V, the effective value is 539V, and the voltage does not reach zero during the cycle.

[0007] Based on the above, under the three-phase four-wire connection conditions, whether it is half-wave rectification or full-wave rectification, the voltage cannot cross zero. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the prior art and provide a leakage protection circuit and device.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A leakage protection circuit comprises: a power supply circuit, a leakage detection circuit, a tripping circuit, a control circuit and a test circuit S1;

[0011] The test circuit S1 includes at least one opening and closing breakpoint synchronized with the opening and closing of the leakage protection device;

[0012] The power supply circuit includes a first L-phase power supply branch L1, a second L-phase power supply branch L2, a third L-phase power supply branch L3, an N-phase power supply branch, and a rectifier circuit;

[0013] The rectifier circuit includes: a diode VD1, a diode VD2, a diode VD3, a diode VD4, a diode VD5, and a diode VD6;

[0014] The first L-phase power branch L1 is connected to the cathode of the diode VD2, and half-wave rectification is achieved through the diode VD2; the second L-phase power branch L2 is connected to the anode of the diode VD5, and half-wave rectification is achieved through the diode VD5;

[0015] The third L-phase power branch L3 is connected to the cathode of the diode VD3 and the anode of the diode VD6 respectively, and full-wave rectification is realized by the diode VD3 and the diode VD6. The opening and closing breakpoints of the test circuit S1 are connected in series between the third L-phase power branch L3 and the rectifier circuit, so that the opening and closing of the third L-phase power branch L3 is synchronized with the opening and closing of the leakage protection device;

[0016] The N-phase power supply branch is connected to the cathode of the diode VD1 and the anode of the diode VD4 respectively, and full-wave rectification is achieved through the diode VD1 and the diode VD4.

[0017] Preferably, the test circuit S1 includes a test resistor R60, a test breakpoint driven by a test button, and an opening and closing breakpoint driven by the opening and closing operation of the leakage protection device. The test breakpoint, the opening and closing breakpoint and the test resistor R60 are all connected in series in the loop of the test circuit S1, and the opening and closing breakpoint is connected in series between the third L-phase power supply branch L3 and the rectifier circuit.

[0018] Preferably, the leakage detection circuit includes: a zero-sequence transformer TA, a detection circuit, and a detection chip, the detection end of the detection circuit is connected to the zero-sequence transformer TA, the output end of the detection circuit is connected to the signal input pin of the detection chip, the signal output pin OS of the detection chip is connected to the control circuit, the detection circuit is used to detect the signal of the zero-sequence transformer TA and input it to the detection chip, and the detection chip controls the control circuit according to the signal of the detection circuit.

[0019] Preferably, the detection circuit includes: at least one action value resistor, a bidirectional diode D1, a series resistor R2, a series resistor R3, and a capacitor C1, the action value resistor is connected in parallel to the two terminals of the zero-sequence transformer TA, the first end of the series resistor R2 is connected in series with the zero-sequence transformer TA and the first end of the action value resistor, the second end of the series resistor R2 is connected to the first input pin I n1 of the detection chip, the first end of the series resistor R3 is connected in series with the zero-sequence transformer TA and the second end of the action value resistor, and the second end of the series resistor R3 is connected to the second input pin I n2 of the detection chip;

[0020] Preferably, the detection circuit also includes: a filter capacitor C3 and a filter capacitor C2; one end of the filter capacitor C3 is connected in parallel to the second end of the series resistor R2, and the other end is grounded; one end of the filter capacitor C2 is connected in parallel to the second end of the series resistor R3, and the other end is grounded.

[0021] Preferably, the cathode of the diode VD5, the cathode of the diode VD6, and the cathode of the diode VD4 are connected together as the first output end of the rectifier circuit, and the first output end of the rectifier circuit is connected to the tripping circuit and the control circuit;

[0022] The anode of the diode VD2, the anode of the diode VD3 and the anode of VD1 are connected together as the second output end of the rectifier circuit, and the second output end of the rectifier circuit is connected to the tripping circuit, the control circuit, and / or the ground GND.

[0023] Preferably, two ends of the test circuit S1 are connected between the N-phase power branch and the third L-phase power branch L3.

[0024] Preferably, the tripping circuit includes tripping coils KA1, KA2 and a diode VD7 connected in parallel therewith, the cathode of the diode VD7 is connected to the power supply circuit, and the anode of the diode VD7 is connected to the detection chip power supply terminal VDD of the leakage detection circuit.

[0025] Preferably, a series resistor R5, a series resistor R6, and a filter capacitor C7 are connected in parallel between the diode VD7 and the power supply terminal VDD of the detection chip.

[0026] Preferably, the control circuit includes: a thyristor VT1 connected in parallel to the tripping circuit, a thyristor VT2 connected in series to the thyristor VT1, a series resistor R4 connected to the G pole of the thyristor VT1, and a diode VD8 connected in series with the series resistor R4, the G pole of the thyristor VT2 is connected to the signal output end of the leakage detection circuit, the positive pole of the diode VD8 is connected to the output end of the power supply circuit, and the negative pole of the diode VD8 is connected to the series resistor R4.

[0027] Preferably, a filter capacitor C4 is also connected in parallel to the G pole of the thyristor VT2.

[0028] An embodiment of the present invention also provides a leakage protection device, including any of the aforementioned leakage protection circuits. When the leakage protection device is closed, the handle, operating mechanism or moving contact drives the opening and closing breakpoint of the test circuit S1 to close, or the opening and closing breakpoint is automatically reset and closed; when the leakage protection device is opened, the handle, operating mechanism or moving contact drives the opening and closing breakpoint to open, or the opening and closing breakpoint is automatically reset and opened.

[0029] The power supply part of the leakage protection circuit of the embodiment of the present invention adopts three-phase four-wire rectification. By connecting one phase line adopting full-wave rectification to the breakpoint of the test circuit and the opening and closing of the circuit breaker, the other phase lines adopt half-wave rectification. The test circuit is at least a double-breakpoint test circuit and is synchronized with the opening and closing of the circuit breaker. When one phase of the full-wave rectification connected to the test circuit is disconnected, while the other two phases are kept to take power normally, the half-wave rectification of the other two phases can be realized, the voltage across the thyristor can reach zero, and then the coil is stopped from conducting. When the input and output lines are connected incorrectly (reverse wiring), the thyristor can be turned off, thereby realizing the reverse wiring function of the three-phase four-wire residual current operated circuit breaker, ensuring the safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a circuit schematic diagram of the leakage protection circuit of the present invention (power supply circuit part);

[0031] Figure 2 It is a circuit schematic diagram of the leakage protection circuit of the present invention (leakage detection circuit part);

[0032] Figure 3 is an equivalent circuit diagram of a power supply circuit according to an embodiment of the present invention;

[0033] Figure 4 yes Figure 3 Simulated diagram of voltage across the thyristor with one phase line disconnected under wiring conditions;

[0034] Figure 5 It is an equivalent circuit diagram of an existing power supply circuit (three-phase three-wire);

[0035] Figure 6 yes Figure 5 Simulation diagram of voltage across thyristor under wiring conditions;

[0036] Figure 7 is based on Figure 5 Consider the equivalent circuit diagram of three-phase four-wire half-wave rectification;

[0037] Figure 8 yes Figure 7 Simulation diagram of voltage across thyristor under wiring conditions;

[0038] Fig. 9 It is an equivalent circuit diagram based on the concept of three-phase four-wire full-bridge rectification;

[0039] Fig.10 yes Fig. 9 Simulation diagram of voltage across thyristor under wiring conditions;

[0040] Fig.11 is another assumed equivalent circuit diagram based on this embodiment;

[0041] Fig.12 yes Fig.11 Simulation diagram of the voltage across the thyristor under wiring conditions. DETAILED DESCRIPTION

[0042] The specific implementation of the socket and the power-on / off structure of the present invention is further described below in conjunction with the embodiments given in the accompanying drawings. The socket and the power-on / off structure of the present invention are not limited to the description of the following embodiments.

[0043] like Figure 1 and Figure 2As shown, the present embodiment provides a leakage protection circuit for a leakage protection device, such as a circuit breaker. The circuit includes: a power supply circuit 110, a leakage detection circuit 120, a tripping circuit 130, and a control circuit 140, wherein the input end of the power supply circuit 110 is connected to the L phase and the N phase, and the two ends of the test circuit S1 are connected between the N phase and at least one L phase. The test circuit S1 in the present embodiment is at least a double-breakpoint test circuit, and its breaking process is synchronized with the opening and closing of the circuit breaker. The test circuit S1 includes at least one opening and closing breakpoint synchronized with the opening and closing of the leakage protection device. For example, an embodiment of the test circuit S1 has a test breakpoint driven by a test button, and an opening and closing breakpoint driven by the opening and closing operation of the leakage protection device. For example, the opening and closing breakpoint is driven by the handle, operating mechanism or moving contact of the leakage protection device. When the leakage protection device is closed, the handle, operating mechanism or moving contact drives the opening and closing breakpoint to close, or the opening and closing breakpoint automatically resets and closes; when the leakage protection device is opened, the handle, operating mechanism or moving contact drives the opening and closing breakpoint to open, or the opening and closing breakpoint automatically resets and opens. When the leakage protection device is closed, the opening and closing breakpoint is closed, and the test button is pressed to drive the test breakpoint to close, and the test circuit S1 is turned on. At this time, the leakage detection circuit 120 detects the simulated leakage current generated by the experimental circuit S1, and transmits the detection signal to the control circuit 140. The control circuit 140 triggers the circuit breaker to trip through the trip circuit 130 to achieve leakage detection. The same is true when leakage occurs. The leakage detection circuit 120 transmits a leakage signal to the control circuit 140 , and the control circuit 140 triggers the circuit breaker to trip through the trip circuit 130 .

[0044] Specifically, in this embodiment, the power supply circuit 110 includes a first L-phase power supply branch L1, a second L-phase power supply branch L2, a third L-phase power supply branch L3, an N-phase power supply branch 114, a rectifier circuit 115, and a test circuit S1; the rectifier circuit 115 includes: a diode VD1, a diode VD2, a diode VD3, a diode VD4, a diode VD5, and a diode VD6. The first L-phase power supply branch L1, the second L-phase power supply branch L2, the third L-phase power supply branch L3, and the N-phase power supply branch 114 can be used to connect the A phase, the B phase, the C phase, and the N phase (neutral phase) respectively. The first L-phase power supply branch L1, the second L-phase power supply branch L2, the third L-phase power supply branch L3, and the N-phase power supply branch 114 are connected to the rectifier circuit 115, and the rectifier circuit 115 outputs to the trip circuit 130 and the control circuit 140 after rectification. Of course, a corresponding step-down circuit may be included between the rectifier circuit 115 and the trip circuit 130 , as well as the control circuit 140 , and the leakage protection circuit may also include other circuits.

[0045] In this embodiment, the first L-phase power branch L1 is connected to the cathode of the diode VD2, and half-wave rectification is achieved through the diode VD2; the second L-phase power branch L2 is connected to the anode of the diode VD5, and half-wave rectification is achieved through the diode VD5; the third L-phase power branch L3 is connected to the cathode of the diode VD3 and the anode of the diode VD6, respectively, and full-wave rectification is achieved through the diode VD3 and the diode VD6. The third L-phase power branch L3 is connected to the test circuit S1, so that the third L-phase power branch L3 is connected to the test circuit S1. The disconnection of the circuit L3 is kept synchronous with the opening and closing of the leakage protection device, that is, the opening and closing breakpoints of the test circuit S1 and the opening and closing of the leakage protection device are connected in series in the third L-phase power branch L3. In this embodiment, the opening and closing breakpoints are connected in series between the third L-phase power branch L3 and the rectifier circuit 115, that is, between the third L-phase power branch L3 and the diode VD3 and the diode VD6; the N-phase power branch 114 is connected to the cathode of the diode VD1 and the anode of the diode VD4 respectively, and full-wave rectification is achieved through the diode VD1 and the diode VD4. The two ends of the test circuit S1 are connected between the N-phase power branch and the third L-phase power branch L3. In this embodiment, when the circuit breaker is opened, the full-wave rectified third L-phase power branch L3 is disconnected, and the first L-phase power branch L1 and the second L-phase power branch L2 are half-wave rectified, so zero crossing can be achieved. The cathode of diode VD5, the cathode of diode VD6, and the cathode of diode VD4 are connected together as a first output end of the rectifier circuit 115, and the first output end is connected to the tripping circuit 130 and the control circuit 140; the anode of diode VD2, the anode of diode VD3, and the anode of VD1 are connected together as a second output end of the rectifier circuit 115, and the second output end is connected to the tripping circuit 130, the control circuit 140, and / or the ground GND.

[0046] like Figure 3 As shown, it is a simplified equivalent circuit diagram of the power supply circuit in this embodiment. Figure 4 The voltage simulation diagram of the two ends of the thyristor is based on the equivalent circuit diagram. When the product is tripped, the C phase is disconnected synchronously (equivalent to disconnecting the third L phase branch). According to the simulation results, the maximum voltage across the thyristor is 563V, the minimum is 0V, the effective value is 212V, and the voltage can reach zero during the cycle. In other words, when one phase of the full-wave rectifier connected to the test circuit is disconnected, while the other two phases are kept to operate normally, the half-wave rectification of the other two phases can be achieved, the voltage across the thyristor can reach zero, and then the coil is stopped from conducting. The thyristor can also be turned off when the input and output lines are connected incorrectly (reverse wiring), thereby realizing the reverse wiring function of the three-phase four-wire residual current operated circuit breaker and ensuring the safety of the product.

[0047] Further, in the present embodiment, the test circuit S1 includes a test resistor R60, which is used to ensure that the voltage is within an acceptable range, and also includes two breakpoints, which are a test breakpoint driven by a test button and a switch-on / off breakpoint driven by the switch-on / off operation of the leakage protection device. The test breakpoint, the switch-on / off breakpoint and the test resistor R60 are all connected in series in the loop of the test circuit S1 and pass through the zero-sequence mutual inductor TA. At the same time, the switch-on / off breakpoint is also connected in series between the third L-phase power branch L3 and the rectifier circuit 115. It should also be noted that the test circuit S1 may also include three breakpoints or more breakpoints.

[0048] In this embodiment, the leakage detection circuit 120 includes: a zero-sequence mutual inductor TA, a detection circuit 121, and a detection chip 122. The detection chip 122 of this embodiment is LW301S / FM2147B, but is not limited to this chip type. The detection end of the detection circuit 121 is connected to the zero-sequence mutual inductor TA, the output end of the detection circuit 121 is connected to the signal input pins I n1 and I n2 of the detection chip 122, the signal output pin OS of the detection chip 122 is connected to the control circuit 140, the detection circuit is used to detect the signal of the zero-sequence mutual inductor TA, and input it to the detection chip, the detection chip controls the control circuit according to the signal of the detection circuit, and outputs a control signal to the control circuit.

[0049] Specifically, the detection circuit 121 includes: at least one action value resistor (R*, R**), a bidirectional diode D1, a series resistor R2, a series resistor R3, and a capacitor C1, wherein the value of the action value resistor (R*, R**) is mainly adjusted and selected according to the residual current action value. To illustrate with an example, the action value resistor may include a resistor R* and a resistor R** connected in parallel therewith, the action value resistor (R*, R**) is connected in parallel to two terminals of the zero-sequence transformer TA, the first end of the series resistor R2 is connected in series with the zero-sequence transformer TA and the first end of the action value resistor (R*, R**), the second end of the series resistor R2 is connected to the first input pin I n1 of the detection chip, the first end of the series resistor R3 is connected in series with the zero-sequence transformer TA and the second end of the action value resistor (R*, R**), and the second end of the series resistor R3 is connected to the second input pin I n2 of the detection chip.

[0050] Furthermore, the detection circuit 121 also includes: a filter capacitor C3 and a filter capacitor C2; one end of the filter capacitor C3 is connected in parallel to the second end of the series resistor R2, and the other end is grounded; one end of the filter capacitor C2 is connected in parallel to the second end of the series resistor R3, and the other end is grounded. The filter capacitor C3 and the filter capacitor C2 are used to filter out clutter signals to ensure that the signal value input to the detection chip is reliable. Furthermore, a filter capacitor C1 is also connected between the second end of the series resistor R2 and the second end of the series resistor R3 to reduce noise interference.

[0051] In this embodiment, the trip circuit 130 includes trip coils KA1, KA2 and a diode VD7 connected in parallel therewith, the cathode of the diode VD7 is connected to the power circuit, and the anode of the diode VD7 is connected to the power supply terminal VDD of the detection chip of the leakage detection circuit. The VSS terminal and the NC terminal of the detection chip are grounded, and the DIY terminal and the OA terminal are respectively connected in series with capacitors C5 and C6 and grounded.

[0052] Furthermore, a series resistor R5, a series resistor R6, and a filter capacitor C7 are connected in parallel between the diode VD7 and the power supply terminal VDD of the detection chip. The series resistor R5 and the series resistor R6 ensure that the voltage input to the power supply terminal VDD of the detection chip is within a reasonable range (i.e., a voltage reduction effect) so as not to burn the detection chip. At the same time, the filter capacitor C7 ensures the reliability of the voltage signal of the power supply terminal VDD and filters out clutter signals.

[0053] In this embodiment, the control circuit includes: a thyristor VT1 connected in parallel to the trip circuit 130, a thyristor VT2 connected in series to the thyristor VT1, a series resistor R4 connected to the G pole of the thyristor VT1, and a diode VD8 connected in series with the series resistor R4, the G pole of the thyristor VT2 is connected to the signal output end of the leakage detection circuit (i.e., the OS end of the detection chip 122), the positive pole of the diode VD8 is connected to the output end of the power supply circuit, and the negative pole of the diode VD8 is connected to the series resistor R4. In addition, the thyristor VT1 and the thyristor VT2 are also connected in parallel with a varistor. When the voltage is large enough, in order to protect the safety of the device, the resistance of the varistor is reduced, and a shunt is generated to protect the safety of the device.

[0054] Furthermore, a filter capacitor C4 is connected in parallel to the G pole of the thyristor VT2 to ensure that the signal output from the OS terminal of the detection chip 122 is free of impurities.

[0055] Based on the above, reference Figure 3 and Figure 4It can be seen that, under the condition of three-phase four-wire connection, when the circuit breaker of the power supply circuit of this embodiment is opened, one power branch is disconnected, while the other two phases are kept to operate normally, so that the DC voltage after rectification can pass through zero, and the voltage across the thyristor can pass through zero, so that the thyristor can be turned off when the input and output lines are connected incorrectly (reverse wiring), thereby realizing the reverse wiring function.

[0056] like Fig.11 and Fig.12 As shown, when the same power supply circuit is used, the A phase (equivalent to the first L phase power supply branch) is disconnected, the maximum voltage across the thyristor is 563V, the minimum is 36V, and the effective value is about 300V. The voltage cannot reach zero during the cycle. When the product is tripped, the B phase is disconnected synchronously, and the result is the same as the A phase. It can be seen that only when the A phase (equivalent to the first L phase power supply branch) and the B phase (equivalent to the second L phase power supply branch) use half-wave rectification and disconnect the C phase (equivalent to the third L phase power supply branch) of the full-bridge rectification, can the voltage be realized to cross zero. Therefore, in this embodiment, the third L phase power supply branch is connected to the test circuit, and its disconnection is synchronized with the circuit breaker opening and closing. When the leakage protection is on, the circuit breaker is opened, the third L phase power supply branch is disconnected, and the first L phase power supply branch and the second L phase power supply branch are half-wave rectified at this time, and the voltage can be realized to cross zero.

[0057] Based on the above, the present invention also provides a leakage protection device, including the leakage protection circuit described in the above embodiment, and the leakage protection device can be a switching electrical appliance such as a circuit breaker.

[0058] It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicate directions or positional relationships based on directions or positional relationships shown in the accompanying drawings, or directions or positional relationships that are usually placed when in use, and are only for the convenience of description, rather than indicating that the device or element referred to must have a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish descriptions, and cannot be understood as indicating relative importance.

[0059] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A leakage protection circuit, comprising: A power supply circuit (110), a leakage detection circuit (120), a tripping circuit (130), a control circuit (140) and a test circuit S1; characterized in that: The test circuit S1 includes at least one opening and closing breakpoint synchronized with the opening and closing of the leakage protection device; The power supply circuit (110) comprises a first L-phase power supply branch L1, a second L-phase power supply branch L2, a third L-phase power supply branch L3, an N-phase power supply branch (114), and a rectifier circuit (115); The rectifier circuit (115) comprises: a diode VD1, a diode VD2, a diode VD3, a diode VD4, a diode VD5, and a diode VD6; The first L-phase power branch L1 is connected to the cathode of the diode VD2, and half-wave rectification is achieved through the diode VD2; The second L-phase power supply branch L2 is connected to the positive electrode of the diode VD5, and half-wave rectification is achieved through the diode VD5; The third L-phase power branch L3 is connected to the cathode of the diode VD3 and the anode of the diode VD6 respectively, and full-wave rectification is achieved through the diode VD3 and the diode VD6. The opening and closing breakpoints of the test circuit S1 are connected in series between the third L-phase power branch L3 and the rectifier circuit (115), so that the opening and closing of the third L-phase power branch L3 is synchronized with the opening and closing of the leakage protection device. The N-phase power supply branch (114) is respectively connected to the cathode of the diode VD1 and the anode of the diode VD4, and full-wave rectification is achieved through the diode VD1 and the diode VD4.

2. The leakage protection circuit according to claim 1, characterized in that: The test circuit S1 comprises a test resistor R60, a test breakpoint driven by a test button, and an opening and closing breakpoint driven by an opening and closing operation of a leakage protection device. The test breakpoint, the opening and closing breakpoint and the test resistor R60 are all connected in series in a loop of the test circuit S1, and the opening and closing breakpoint is connected in series between the third L-phase power supply branch L3 and the rectifier circuit (115).

3. The leakage protection circuit according to claim 1, characterized in that: The leakage detection circuit (120) comprises: a zero-sequence transformer TA, a detection circuit (121), and a detection chip (122); the detection end of the detection circuit (121) is connected to the zero-sequence transformer TA, the output end of the detection circuit (121) is connected to a signal input pin (In1, In2) of the detection chip (122), the signal output pin OS of the detection chip (122) is connected to the control circuit (140), the detection circuit (121) is used to detect a signal of the zero-sequence transformer TA and input the signal to the detection chip (122), and the detection chip (122) controls the control circuit (140) according to the signal of the detection circuit.

4. The leakage protection circuit according to claim 3, characterized in that: The detection circuit includes: at least one action value resistor (R*, R**), a bidirectional diode D1, a series resistor R2, a series resistor R3, and a capacitor C1, the action value resistor (R*, R**) is connected in parallel to the two connection terminals of the zero-sequence transformer TA, the first end of the series resistor R2 is connected in series with the zero-sequence transformer TA and the first end of the action value resistor (R*, R**), the second end of the series resistor R2 is connected to the first input pin In1 of the detection chip, the first end of the series resistor R3 is connected in series with the zero-sequence transformer TA and the second end of the action value resistor (R*, R**), and the second end of the series resistor R3 is connected to the second input pin In2 of the detection chip.

5. The leakage protection circuit according to claim 4, characterized in that: The detection circuit also includes: a filter capacitor C3 and a filter capacitor C2; one end of the filter capacitor C3 is connected in parallel to the second end of the series resistor R2, and the other end is grounded; one end of the filter capacitor C2 is connected in parallel to the second end of the series resistor R3, and the other end is grounded.

6. The leakage protection circuit according to claim 1, characterized in that: The cathode of the diode VD5, the cathode of the diode VD6, and the cathode of the diode VD4 are connected together as a first output end of a rectifier circuit (115), and the first output end of the rectifier circuit (115) is connected to a trip circuit (130) and a control circuit (140); The anode of the diode VD2, the anode of the diode VD3, and the anode of VD1 are connected together as the second output end of the rectifier circuit (115), and the second output end of the rectifier circuit (115) is connected to the tripping circuit (130), the control circuit (140), and / or the ground GND.

7. The leakage protection circuit according to claim 1, characterized in that: Both ends of the test circuit S1 are connected between the N-phase power branch and the third L-phase power branch L3.

8. The leakage protection circuit according to claim 1, characterized in that: The tripping circuit comprises a tripping coil (KA1, KA2) and a diode VD7 connected in parallel therewith, wherein the cathode of the diode VD7 is connected to the power supply circuit (110), and the anode of the diode VD7 is connected to the detection chip power supply terminal VDD of the leakage detection circuit.

9. The leakage protection circuit according to claim 8, characterized in that: A series resistor R5, a series resistor R6, and a filter capacitor C7 are connected in parallel between the diode VD7 and the power supply terminal VDD of the detection chip.

10. A leakage protection device, characterized in that: It includes a leakage protection circuit as described in any one of claims 1 to 9, when the leakage protection device is closed, the handle, operating mechanism or moving contact drives the opening and closing breakpoint of the test circuit S1 to close, or the opening and closing breakpoint is automatically reset and closed; when the leakage protection device is opened, the handle, operating mechanism or moving contact drives the opening and closing breakpoint to open, or the opening and closing breakpoint is automatically reset and opened.

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