CN221353909U

CN221353909U - Leakage protection circuit

Info

Publication number: CN221353909U
Application number: CN202322946710.0U
Authority: CN
Inventors: 蔡峰毅; 许海恩; 陈金环
Original assignee: Xiamen Ztc Technology Co ltd
Current assignee: Xiamen Ztc Technology Co ltd
Priority date: 2023-10-31
Filing date: 2023-10-31
Publication date: 2024-07-16
Anticipated expiration: 2033-10-31

Abstract

The utility model discloses a leakage protection circuit, which comprises a zero sequence current transformer, a leakage protection chip, a release driving circuit and a power supply conversion circuit, wherein the zero sequence current transformer is sleeved on a live wire and a zero wire to be protected, the output end of a secondary coil of the zero sequence current transformer is connected with the input end of the leakage protection chip, the output end of the leakage protection chip is connected with the control end of the release driving circuit, the release is at least connected on the live wire to be protected in series, the input end of the power supply conversion circuit is connected with the live wire and the zero wire to be protected, and the power supply conversion circuit is used for supplying power to the leakage protection chip. The utility model can realize AC type leakage protection, 0 degree, 90 degree and 135 degree residual pulsation direct current leakage protection and residual pulsation direct current superposition 6mA smooth direct current leakage protection, greatly improves the safety and reliability of the electric appliance, and has simple circuit, stable performance and reliable action.

Description

Leakage protection circuit

Technical Field

The utility model belongs to the technical field of leakage protection, and particularly relates to a leakage protection circuit.

Background

Various electric appliances are almost kept away in life of people, and with the increasing popularization of electric appliances, the opportunities of people to be in contact with the electric appliances are increased, and in order to better protect users, the power supply circuits of many electric appliances are provided with leakage protection circuits, so that the users are prevented from being damaged by electric shock, and the life safety and equipment safety of the users are protected. At present, the most used AC type leakage protection circuit in the market, but with the rising of the electric appliance technology, the detection requirement on the leakage is also improved, because the leakage signal in the occasions such as the electric appliance has alternating current type and pulsating direct current type, and the conventional AC type leakage protection circuit can not detect the pulsating direct current type leakage signal, so that the refusal action occurs, and the personal safety of a user or the safety of equipment is seriously influenced. Although some A-type leakage protection circuits exist, the circuit structure is complex and the reliability is low.

Disclosure of Invention

The present utility model is directed to a leakage protection circuit for solving the above-mentioned problems.

In order to achieve the above purpose, the utility model adopts the following technical scheme: the utility model provides a leakage protection circuit, including zero sequence current transformer, earth leakage protection chip, the release, release drive circuit and power conversion circuit, zero sequence current transformer cover is established on the live wire and the zero line that wait to protect, zero sequence current transformer's secondary coil's output termination earth leakage protection chip's input, earth leakage protection chip's output termination release drive circuit's control end, release drive circuit is used for driving the break-make of release, the release concatenates on the live wire that wait to protect at least, power conversion circuit's input receives the live wire and the zero line that wait to protect, power conversion circuit is used for supplying power for earth leakage protection chip.

Further, the model of the leakage protection chip is FM2147B, and two ends of a secondary coil of the zero sequence current transformer are respectively connected with an RCI1 end and an RCI2 end of the leakage protection chip.

Further, the leakage protection device further comprises resistors R4 and R5, wherein the first ends of the resistors R4 and R5 are respectively connected with two ends of a secondary coil of the zero sequence current transformer, and the second ends of the resistors R4 and R5 are respectively connected with an RCI1 end and an RCI2 end of the leakage protection chip.

Further, the zero sequence current transformer further comprises a resistor R3 ^*, and the resistor R3 ^* is connected between two ends of the secondary coil of the zero sequence current transformer.

Further, the capacitor C1 and the capacitor C2 are also included, the capacitor C1 is arranged in parallel with the resistor R3 ^*, and the capacitor C2 is connected between the second ends of the resistors R4 and R5.

Further, the release driving circuit comprises a silicon controlled rectifier SCR which is connected in series in a coil loop of the release, and a control electrode of the silicon controlled rectifier SCR is connected with a TRIG end of the leakage protection chip.

Further, the power supply conversion circuit comprises a rectifying circuit and a voltage reducing circuit, wherein the input end of the rectifying circuit is connected with a live wire and a zero wire to be protected, the input end of the voltage reducing circuit is connected with the output end of the rectifying circuit, and the voltage reducing circuit supplies power for the leakage protection chip.

Furthermore, the voltage reducing circuit comprises a resistor R2 and a zener diode D1, wherein the first end of the resistor R2 is connected with the positive output end of the rectifying circuit, the second end of the resistor R2 is connected with the VDD end of the leakage protection chip, and the zener diode D1 is connected between the second end of the resistor R2 and the ground GND.

Further, the step-down circuit further includes a filter capacitor C6, where the filter capacitor C6 is parallel connected to the zener diode D1.

Further, the release is a double-contact release, and the double contacts are respectively connected in series on a live wire and a zero wire to be protected.

The beneficial technical effects of the utility model are as follows:

The utility model can realize AC type leakage protection, 0 degree, 90 degree and 135 degree residual pulsation direct current leakage protection and residual pulsation direct current superposition 6mA smooth direct current leakage protection, greatly improves the safety and reliability of the electric appliance, and has simple circuit, stable performance and reliable action.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings that are needed in the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a circuit diagram of an embodiment of the present utility model.

Detailed Description

For further illustration of the various embodiments, the utility model is provided with the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments and together with the description, serve to explain the principles of the embodiments. With reference to these matters, one of ordinary skill in the art will understand other possible embodiments and advantages of the present utility model. The components in the figures are not drawn to scale and like reference numerals are generally used to designate like components.

The utility model will now be further described with reference to the drawings and detailed description.

As shown in fig. 1, the leakage protection circuit comprises a zero sequence current transformer ZCT, a leakage protection chip U2, a release TK, a release driving circuit and a power conversion circuit, wherein the zero sequence current transformer ZCT is sleeved on a live wire L and a zero wire N to be protected, namely, the live wire L and the zero wire N to be protected pass through the zero sequence current transformer ZCT, the output end of a secondary coil of the zero sequence current transformer ZCT is connected with the input end of the leakage protection chip U2, the output end of the leakage protection chip U2 is connected with the control end of the release driving circuit, the release driving circuit is used for driving the on-off of the release TK, the release TK is at least connected on the live wire L to be protected in series, the input end of the power conversion circuit is connected with the live wire L and the zero wire N to be protected, and the power conversion circuit is used for supplying power to the leakage protection chip U2.

In this embodiment, the zero sequence current transformer ZCT is implemented by using an existing zero sequence current transformer, which may be an integral zero sequence current transformer, an open zero sequence current transformer, or the like.

In this embodiment, the model of the leakage protection chip U2 is FM2147B, but the invention is not limited thereto, and in some embodiments, the leakage protection chip U2 may be implemented by other existing leakage protection chips that can implement leakage protection. Two ends (output ends) of the secondary coil of the zero sequence current transformer ZCT are respectively connected with an RCI1 end and an RCI2 end (input end) of the leakage protection chip U2.

Further, in this embodiment, the current-limiting protection circuit further includes resistors R4 and R5, the first ends of the resistors R4 and R5 are respectively connected to two ends of the secondary coil of the zero-sequence current transformer ZCT, the second ends of the resistors R4 and R5 are respectively connected to the RCI1 end and the RCI2 end of the leakage protection chip U2, and the resistors R4 and R5 play a role in current-limiting protection to protect the leakage protection chip U2.

In this embodiment, the leakage current adjusting device further includes a resistor R3 ^*, where the resistor R3 ^* is connected between two ends of the secondary coil of the zero-sequence current transformer ZCT, and is used for adjusting the magnitude of the leakage current.

Further, in order to improve the anti-interference capability, the embodiment further includes capacitors C1 and C2, where the capacitor C1 is parallel connected to the resistor R3 ^*, and the capacitor C2 is connected between the second ends of the resistors R4 and R5.

Preferably, the RCI1 end and the RCI2 end of the leakage protection chip U2 are respectively connected in series with the capacitors C3 and C4 to be grounded GND, so as to further improve the anti-interference performance.

In this embodiment, the trip driving circuit includes a silicon controlled rectifier SCR, the silicon controlled rectifier SCR is connected in series in a coil loop of the trip TK, a control electrode (control end of the trip driving circuit) of the silicon controlled rectifier SCR is connected in series with a resistor R6 and connected to a TRIG end (output end) of the leakage protection chip, and the control electrode of the silicon controlled rectifier SCR is also connected in series with a capacitor C7 and grounded GND. However, the present invention is not limited thereto, and in some embodiments, the trip driving circuit may be implemented by using other existing trip driving circuits, such as a trip driving circuit formed by using a MOS transistor, a triode, or the like.

In this embodiment, the power conversion circuit includes a rectifying circuit and a voltage-reducing circuit, the input end of the rectifying circuit is connected to the live wire L and the zero wire N to be protected, the input end of the voltage-reducing circuit is connected to the output end of the rectifying circuit, and the voltage-reducing circuit supplies power to the leakage protection chip U2.

More specifically, in the present embodiment, the rectifying circuit is implemented by using the rectifying bridge U1, but the rectifying effect is not limited thereto, and in some embodiments, the rectifying circuit may be implemented by using other existing rectifying circuits.

The step-down circuit includes a resistor R2 and a zener diode D1, and has a simple circuit structure, easy implementation, and low cost, but is not limited thereto, and in some embodiments, the step-down circuit may be implemented by using other existing step-down circuits.

One input end of the rectifier bridge U1 is connected with a coil connecting live wire L of a release TK in series, the other input end of the rectifier bridge U1 is connected with a zero line N, the negative output end of the rectifier bridge U1 is connected with the ground GND, the positive output end of the rectifier bridge U1 is connected with a silicon controlled rectifier SCR (selective catalytic reduction) ground GND in series, the first end of the resistor R2 is connected with the positive output end of the rectifier bridge U1, the second end of the resistor R2 is connected with the VDD end of the leakage protection chip U2, and the voltage stabilizing diode D1 is connected between the second end of the resistor R2 and the ground GND.

Further, the step-down circuit further comprises a filter capacitor C6, and the filter capacitor C6 and the zener diode D1 are arranged in parallel, so that the power supply stability is further improved.

Preferably, in this embodiment, the trip TK is a double-contact trip, and the double contacts are respectively connected in series to the live wire L and the neutral wire N to be protected, so that the power-off protection is more reliable, but the invention is not limited thereto.

In this embodiment, a varistor MOV is further connected between the live line L and the neutral line N to be protected, so as to perform surge lightning strike protection.

Further, in this embodiment, the device further includes a test circuit, one end of the test circuit receives a zero line N to be protected, the other end of the test circuit passes through a zero sequence current transformer ZCT to receive a live line L to be protected, and the test circuit is connected in series with a test switch AJ and a resistor R1, and when the test switch AJ is turned on, the leakage condition is simulated.

Working principle:

The rectifier bridge U1 rectifies alternating current of the live wire L and the zero line N into direct current to be output, the direct current is subjected to voltage reduction, voltage stabilization and pressure filtration by a voltage reduction circuit to supply power to the leakage protection chip U2, the leakage protection chip U2 works, when the load is subjected to leakage or personal electric shock or equipment insulation damage, the current vector sum of a primary coil of the zero sequence current transformer ZCT is not zero, a secondary coil of the zero sequence current transformer ZCT generates induced voltage, the induced voltage is compared and processed by the leakage protection chip U2, when the residual current reaches a set action current value, a stable and reliable signal is output from a TRIG end of the leakage protection chip U2 to enable the silicon controlled rectifier SCR to be conducted, the tripping device TK acts, the live wire L and the zero line N loops are disconnected, and the power supply is cut off to play a role in leakage and electric shock protection. The AC type electric leakage protection device not only can realize AC type electric leakage protection, but also can realize 0 degree, 90 degrees and 135 degrees of residual pulsating direct current electric leakage protection and residual pulsating direct current superposition 6mA smooth direct current electric leakage protection, and greatly improves the safety and reliability of the electric appliance.

While the utility model has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the utility model as defined by the appended claims.

Claims

1. The utility model provides a leakage protection circuit which characterized in that: the zero sequence current transformer is sleeved on a live wire and a zero wire to be protected, the output end of a secondary coil of the zero sequence current transformer is connected with the input end of the leakage protection chip, the output end of the leakage protection chip is connected with the control end of the release driving circuit, the release driving circuit is used for driving the on-off of the release, the release is at least connected on the live wire to be protected in series, the input end of the power conversion circuit is connected with the live wire and the zero wire to be protected, and the power conversion circuit is used for supplying power for the leakage protection chip.

2. The leakage protection circuit of claim 1, wherein: the model of the leakage protection chip is FM2147B, and two ends of a secondary coil of the zero sequence current transformer are respectively connected with an RCI1 end and an RCI2 end of the leakage protection chip.

3. The leakage protection circuit of claim 2, wherein: the secondary coil of the zero sequence current transformer is connected with the two ends of the secondary coil of the zero sequence current transformer respectively, and the RCI1 end and the RCI2 end of the leakage protection chip are connected with the second ends of the resistors R4 and R5 respectively.

4. A leakage protection circuit according to claim 3, wherein: the zero sequence current transformer also comprises a resistor R3 ^*, and the resistor R3 ^* is connected between two ends of the secondary coil of the zero sequence current transformer.

5. The leakage protection circuit of claim 4, wherein: the capacitor C1 is connected in parallel with the resistor R3 ^*, and the capacitor C2 is connected between the second ends of the resistors R4 and R5.

6. The leakage protection circuit of claim 2, wherein: the release driving circuit comprises a silicon controlled rectifier SCR which is connected in series in a coil loop of the release, and a control electrode of the silicon controlled rectifier SCR is connected with a TRIG end of the leakage protection chip.

7. The leakage protection circuit of claim 2, wherein: the power supply conversion circuit comprises a rectifying circuit and a voltage reducing circuit, wherein the input end of the rectifying circuit is connected with a live wire and a zero wire to be protected, the input end of the voltage reducing circuit is connected with the output end of the rectifying circuit, and the voltage reducing circuit supplies power for the leakage protection chip.

8. The leakage protection circuit of claim 7, wherein: the voltage reduction circuit comprises a resistor R2 and a voltage stabilizing diode D1, wherein the first end of the resistor R2 is connected with the positive output end of the rectifying circuit, the second end of the resistor R2 is connected with the VDD end of the leakage protection chip, and the voltage stabilizing diode D1 is connected between the second end of the resistor R2 and the ground GND.

9. The leakage protection circuit of claim 8, wherein: the step-down circuit further comprises a filter capacitor C6, and the filter capacitor C6 and the zener diode D1 are arranged in parallel.

10. The leakage protection circuit according to claim 1 or 2, characterized in that: the release is a double-contact release, and the double contacts are respectively connected in series on a live wire and a zero wire to be protected.