CN212033756U

CN212033756U - Leakage protection circuit and wisdom street lamp that can independently resume

Info

Publication number: CN212033756U
Application number: CN202020605243.9U
Authority: CN
Inventors: 胡绪桢; 李选中; 吴振志; 吴涵渠
Original assignee: Shenzhen Aoto Electronics Co Ltd
Current assignee: Shenzhen Aoto Electronics Co Ltd
Priority date: 2020-04-21
Filing date: 2020-04-21
Publication date: 2020-11-27
Anticipated expiration: 2030-04-21

Abstract

The utility model relates to an electric leakage protection circuit and an intelligent street lamp capable of self-recovery, wherein, the electric leakage protection circuit comprises an electric leakage detection unit, a circuit on-off control unit, a working voltage generation unit and a time delay recovery unit; the load is connected with an input power supply through a circuit on-off control unit; the leakage detection unit outputs a leakage signal when detecting leakage; the circuit on-off control unit is used for receiving the leakage signal output by the leakage detection unit, disconnecting a connecting channel between the input power supply and the load and generating a delay control signal; the delay recovery unit receives the delay control signal output by the on-off control unit of the circuit and outputs a recovery control signal after the preset delay time; and the line on-off control unit is used for communicating a connecting passage between the input power supply and the load when receiving the recovery control signal. The power supply can be automatically recovered, the leakage protection situation caused by accidental leakage can be effectively coped with, and the normal state can be timely recovered.

Description

Leakage protection circuit and wisdom street lamp that can independently resume

Technical Field

The utility model relates to an intelligence street lamp field especially relates to a leakage protection circuit and wisdom street lamp that can independently resume.

Background

The intelligent street lamp is the basis of intelligent city construction, integrates multiple functional equipment such as illumination, demonstration, broadcasting, security protection control, is the node of various data acquisition, perceptions. Street lights may have electrical leakage problems for a variety of reasons. Therefore, in consideration of safety protection, the existing street lamp is generally provided with an electric leakage protection circuit, when electric leakage is detected, an input power supply path of the street lamp is directly cut off, and power supply can not be recovered until maintenance personnel finish overhauling. However, in an actual scene, the leakage of the street lamp can be eliminated in a short time only by accident, and the danger to the outside cannot be continuously generated. The existing leakage protection circuit cannot identify the accidental leakage, and the input power supply can be cut off all the time under the condition of the accidental leakage, so that the street lamp is always in a power-off state and cannot be restored to a normal state, and the lighting function of the street lamp is greatly influenced.

SUMMERY OF THE UTILITY MODEL

Therefore, it is necessary to provide an automatic recovery leakage protection circuit and an intelligent street lamp for solving the problem that the leakage protection circuit of the street lamp cannot recognize accidental leakage.

The utility model provides an embodiment provides an electric leakage protection circuit capable of self-recovering, which comprises an electric leakage detection unit, a circuit on-off control unit, a working voltage generation unit and a time delay recovery unit;

the input power supply is connected with the circuit on-off control unit, and the load is connected with the input power supply through the circuit on-off control unit;

the leakage detection unit is used for detecting whether leakage occurs in the circuit or not and outputting a leakage signal when the leakage is detected;

the working voltage generating unit is connected with an input power supply and used for generating direct-current working voltage;

the circuit on-off control unit is electrically connected with the electric leakage detection unit, the working voltage generation unit and the delay recovery unit; the circuit on-off control unit receives the leakage signal output by the leakage detection unit, disconnects a connecting channel between an input power supply and a load and generates a delay control signal;

the delay recovery unit is electrically connected with the working voltage generation unit and the circuit on-off control unit; the delay recovery unit receives the delay control signal output by the circuit on-off control unit and outputs a recovery control signal after a preset delay time;

and the line on-off control unit is communicated with a connecting passage between an input power supply and a load when receiving the recovery control signal output by the delay recovery unit.

In some embodiments, the input power source comprises a live end and a neutral end, and the power line connecting the load comprises a live and a neutral; the leakage detection unit comprises a mutual inductor, a first rectifier bridge, a silicon controlled rectifier, a first resistor, a first capacitor and a first relay, wherein the mutual inductor comprises a magnetic ring and a winding wound on the magnetic ring, a line of a live wire and a zero line penetrates through the mutual inductor, and the first resistor and the first capacitor are arranged between two ends of the winding in parallel; one end of the winding is connected with the direct-current output negative end of the first rectifier bridge and the negative electrode of the controlled silicon, the other end of the winding is connected with the control electrode of the controlled silicon, and the direct-current output positive end of the first rectifier bridge is connected with the anode of the controlled silicon; one alternating current input end of the first rectifier bridge and the input end of the first relay are connected with one of the live wire and the zero wire; the other alternating current input end of the first rectifier bridge is connected with one control end of the first relay; the other control end of the first relay is connected with the other of the live wire and the zero wire, and the normally open contact of the first relay is used as the output end of the leakage signal.

In some embodiments, the operating voltage generating unit includes a second capacitor, a third capacitor, a second resistor, a third resistor, a second rectifier bridge, and a voltage regulator tube, and an ac input end of the second rectifier bridge is connected to one of a live wire end and a neutral wire end of the input power supply through the second capacitor; the other alternating current input end of the second rectifier bridge is connected with the other of the live wire end and the zero wire end of the input power supply; the second resistor and the third resistor are connected in series to form a discharge branch, and the discharge branch is connected with the second capacitor in parallel; the third capacitor and the voltage-stabilizing tube are arranged in parallel between the direct-current output positive end and the direct-current output negative end of the second rectifier bridge, the direct-current output negative end of the second rectifier bridge is grounded, and the direct-current output positive end outputs working voltage.

In some embodiments, the operating voltage generating unit further includes a fourth capacitor and a three-terminal regulator chip, an input terminal of the three-terminal regulator chip is connected to the positive terminal of the dc output of the second rectifier bridge, and a ground terminal of the three-terminal regulator chip is grounded; and two ends of the fourth capacitor are respectively connected with the output end and the grounding end of the three-terminal voltage stabilizing chip, and the output end of the three-terminal voltage stabilizing chip outputs working voltage.

In some embodiments, the on-off line control unit comprises a second relay, a third relay and a trigger signal relay; the second relay comprises a first channel and a second channel, the input end of the first channel is connected with a live wire end of an input power supply, the normally closed contact of the first channel is connected with a live wire, the input end of the second channel is connected with a zero wire end of the input power supply, the normally closed contact of the second channel is connected with a zero wire, and the normally open contact of the second channel is connected with one control end of the trigger signal relay, the normally open contact of the first relay and one control end of the second relay; the other control end of the second relay is connected with the input end of the third relay;

the normally closed contact of the third relay is connected with a live wire end of an input power supply, one control end of the third relay is connected with working voltage, and the other control end of the third relay receives a recovery control signal;

the other control end of the trigger signal relay is connected with a live wire end of an input power supply, the input end of the trigger signal relay is connected with working voltage, and a normally open contact of the trigger signal relay serves as a delay control signal output end and is used for outputting a delay control signal.

In some embodiments, the delay recovery unit includes a delay control module, the delay control module includes a fourth resistor, a fifth resistor, a sixth resistor, a fifth capacitor, a first triode, and an and gate chip, the and gate chip has at least 2 and gate channels, wherein two input ends of the first and gate channel respectively receive the delay control signal, an output end of the first and gate channel is connected with two input ends of the second and gate channel, an output end of the first and gate channel is further grounded through the fifth capacitor, and the fourth resistor is connected in parallel with the fifth capacitor; the output end of the second and gate channel is connected with the first end of the sixth resistor, the second end of the sixth resistor is connected with the base electrode of the first triode, the base electrode of the first triode is grounded through the fifth resistor, the emitting electrode of the first triode is grounded, and the collecting electrode of the first triode is used as the output end of the recovery control signal and used for outputting the recovery control signal.

In some embodiments, the delay recovery unit comprises a delay control module and a counting module; the counting module comprises a counter, a sixth capacitor and a seventh capacitor, and the delay control module comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a fifth capacitor, a first triode, a second triode and an AND gate chip; the AND gate chip comprises 4 AND gate channels, two input ends of a first AND gate channel receive the delay control signal, an output end of the first AND gate channel is connected with two input ends of a second AND gate channel, an output end of the first AND gate channel is grounded through a fifth capacitor, and a fourth resistor is connected with the fifth capacitor in parallel; the output end of the second and gate channel is connected with two input ends of a fourth and gate channel, the output end of the fourth and gate channel is connected with the first end of a sixth resistor, the second end of the sixth resistor is connected with the base electrode of the first triode, the base electrode of the first triode is grounded through the fifth resistor, and the emitting electrode of the first triode is grounded;

the clock signal end of the counter is connected with the second end of the sixth resistor, the input end of the counter is grounded, 2 output ends of the counter are connected with two input ends of a third AND channel of the AND chip, the output end of the third AND channel is connected with the base electrode of the second triode, the base electrode of the second triode is grounded through the seventh resistor, the collector electrode of the second triode is connected with the collector electrode of the first triode, and the emitter electrode of the second triode is used as a recovery control signal output end and used for outputting a recovery control signal; the second triode is a PNP triode.

In some embodiments, the counting module further comprises a reset key, and the reset terminal of the counter is grounded through the reset key; when the reset key is pressed down, the reset end of the counter is grounded, and the counting in the counter is cleared.

In some embodiments, the delay recovery unit further comprises an alarm, and a port of the alarm is connected with the base of the second triode; and when the counting of the counter reaches a preset time threshold value, the alarm is synchronously triggered to warn.

Another embodiment of the present application further provides a smart street lamp having the self-recoverable leakage protection circuit of any one of the foregoing embodiments.

According to the leakage protection circuit capable of automatically recovering, the delay recovery unit and the line on-off control unit are arranged, so that after the leakage is detected and the connection path between the input power supply and the load is disconnected, the connection path between the input power supply and the load can be recovered after the preset delay time. The leakage protection circuit that can independently resume that this embodiment provided can realize independently resuming the power supply, can effectively deal with the leakage protection situation that accidental electric leakage leads to, in time resumes normal condition.

Drawings

Fig. 1 is a schematic diagram of a frame structure of an earth leakage protection circuit according to an embodiment of the present invention;

fig. 2 is a schematic circuit diagram of an embodiment of the leakage protection circuit of the present invention;

fig. 3 is a schematic circuit diagram of the leakage detecting unit and the operating voltage generating unit according to an embodiment of the present invention;

fig. 4 is a schematic circuit diagram of a delay control module according to an embodiment of the present invention;

fig. 5 is a schematic circuit diagram of a delay recovery unit according to another embodiment of the present invention.

Detailed Description

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in detail with reference to the accompanying drawings and detailed description. In addition, the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As shown in fig. 1 and fig. 2, an embodiment of the present invention provides an electric leakage protection circuit 10 capable of self-recovery, which includes an electric leakage detection unit 100, a circuit on-off control unit 200, a working voltage generation unit 300, and a delay recovery unit 400;

the input power supply is connected with the circuit on-off control unit 200, and the load is connected with the input power supply through the circuit on-off control unit 200;

a leakage detecting unit 100 for detecting whether leakage occurs in the circuit and outputting a leakage signal when leakage is detected;

a working voltage generating unit 300 connected to an input power source for generating a direct current working voltage;

the line on-off control unit 200 is electrically connected with the leakage detection unit 100, the working voltage generation unit 300 and the delay recovery unit 400; a line on-off control unit 200, which disconnects a connection path between an input power supply and a load and generates a delay control signal Pu when receiving the leakage signal output by the leakage detection unit 100;

the delay recovery unit 400 is electrically connected with the working voltage generation unit 300 and the line on-off control unit 200; the delay recovery unit 400 receives the delay control signal Pu output by the line on-off control unit 200, and outputs a recovery control signal RE after receiving a preset delay time of the delay control signal Pu;

the line on-off control unit 200 is configured to connect a connection path between the input power source and the load when receiving the recovery control signal RE output by the delay recovery unit 400.

The leakage detecting unit 100 is used to detect whether leakage occurs in the circuit. The leakage detecting unit 100 may employ a common leakage detecting circuit, such as a voltage-type leakage detecting circuit, a pulse-type leakage detecting circuit, or a current-type leakage detecting circuit. In the present embodiment, the leakage detecting unit 100 is a current leakage detecting circuit. Specifically, as shown in fig. 2 and 3, the input power is two-phase alternating current, the input power includes a live wire end and a zero line end, and the power line connected to the load includes a live wire L and a zero line N; the leakage detection unit 100 may include a transformer CL, a first rectifier bridge B1, a silicon controlled rectifier SCR, a first resistor R1, a first capacitor C1, and a first relay J1, where the transformer CL includes a magnetic ring and a winding wound around the magnetic ring, a line of a live line L and a zero line N passes through the transformer CL, and a first resistor R1 and a first capacitor C1 are arranged between two ends of the winding in parallel; one end of the winding is connected with the direct-current output negative end of the first rectifier bridge B1 and the negative electrode C of the silicon controlled rectifier SCR, the other end of the winding is connected with the control electrode G of the silicon controlled rectifier SCR, and the direct-current output positive end of the first rectifier bridge B1 is connected with the anode A of the silicon controlled rectifier SCR; an alternating current input end of the first rectifier bridge B1 and an input end IN of the first relay J1 are connected with one of a live wire L and a zero wire N; the other alternating current input end of the first rectifier bridge B1 is connected with a control end CO of the first relay J1; the other control end CO of the first relay J1 is connected with the other of the live wire L and the zero wire N, and the normally open contact S of the first relay J1 is used as an output end of a leakage signal.

IN the example shown IN fig. 3, the lower ac input of the first rectifier bridge B1, the input IN of the first relay J1, is connected to the neutral line N; the other control terminal CO of the first relay J1 is connected to the live line L.

When no electric leakage exists, the winding of the mutual inductor CL has no induced current, the SCR is cut off, the first rectifier bridge B1 does not work, the control end of the first relay J1 has no alternating current input, the first relay J1 does not work, the normally open contact S of the first relay J1 is disconnected with the input end IN, and the normally open contact S has no effective electric signal output.

When a leakage condition exists in the circuit, the winding of the transformer CL can generate an induced current to charge the first capacitor C1. After certain charge time, when the level of first electric capacity C1 reached silicon controlled rectifier SCR 'S trigger voltage level, silicon controlled rectifier SCR switched on, and first rectifier bridge B1 work, there is the alternating current input first relay J1' S control end, and first relay J1 'S coil circular telegram for normally open contact S is closed, and first relay J1' S normally open contact S communicates with input IN, and normally open contact S exports leakage signal. In the example shown in fig. 3, the leakage signal output by the normally open contact S is the voltage signal of the live line N.

By configuring the capacitance of the first capacitor C1, the turn-on time of the SCR during leakage can be controlled, and the turn-on time can represent the reaction time of leakage protection. The first resistor R1 is used to discharge the first capacitor C1, so that the first capacitor C1 can be restored to the initial state to perform the leakage detection again.

And the working voltage generating unit 300 is connected to the input power supply, and is configured to generate a working voltage VCC required by the line on-off control unit 200 and the delay recovery unit 400. For example, as shown in fig. 2 and 3, the operating voltage generating unit 300 may include a second capacitor C2, a third capacitor C3, a second resistor R2, a third resistor R3, a second rectifier bridge B2, and a voltage regulator D1, wherein an ac input terminal of the second rectifier bridge B2 is connected to one of a live line terminal L and a neutral line terminal N of the input power through the second capacitor C2; the other alternating current input end of the second rectifier bridge B2 is connected with the other of the live wire end L and the zero wire end N of the input power supply; the second resistor R2 and the third resistor R3 are connected in series to form a discharge branch, and the discharge branch is connected with the second capacitor C2 in parallel; the third capacitor C3 and the voltage regulator tube D1 are connected in parallel between the dc output positive terminal and the dc output negative terminal of the second rectifier bridge B2, the dc output negative terminal of the second rectifier bridge B2 is grounded, and the dc output positive terminal can output the working voltage VCC.

In the embodiment shown in fig. 3, the ac input terminal of the second rectifier bridge B2 located on the upper side is connected to the live line terminal L of the input power source through a second capacitor C2; and the alternating current input end positioned on the lower side is connected with the zero line end N of the input power supply. After the power supply input of the alternating current passes through the second rectifier bridge B2, a direct current signal can be obtained; and then the working voltage VCC can be obtained through the filtering of a third capacitor C3 and the voltage stabilization of a voltage stabilizing tube D1. For example, the operating voltage VCC may be a 5V dc voltage. It is understood that, by adjusting the capacitance of the third capacitor C3, the operating voltage VCC may have other voltage values, which may be selected according to actual needs.

The second capacitor C2 is arranged in series between the ac input end of the second rectifier bridge B2 located at the upper side and the live wire end L of the input power supply, and the second capacitor C2 is provided with the discharge branch formed by connecting the second resistor R2 and the third resistor R3 in series in parallel, so that the current limiting effect can be achieved, the transient overshoot problem when the working voltage generating unit 300 is started can be avoided, and the relatively stable current output can be realized.

In order to further improve the stability of the operating voltage VCC, as shown in fig. 3, the operating voltage generating unit 300 may further include a fourth capacitor C4 and a three-terminal regulator chip U1, an input terminal of the three-terminal regulator chip U1 is connected to the positive terminal of the dc output of the second rectifier bridge B2, and a ground terminal of the three-terminal regulator chip U1 is grounded; the two ends of the fourth capacitor C4 are respectively connected to the output end and the ground end of the three-terminal voltage stabilization chip U1, and the output end of the three-terminal voltage stabilization chip U1 outputs the working voltage VCC. For example, the three-terminal regulator chip U1 may be a common three-terminal regulator IC, such as a 7805 chip.

The circuit on-off control unit 200 is configured to disconnect a connection path between the input power supply and the load and generate a delay control signal Pu when receiving the leakage signal output by the leakage detection unit 100; when receiving the recovery control signal RE output by the delay recovery unit 400, the connection path between the input power source and the load is connected.

For example, as shown IN fig. 3, the on-off line control unit 200 may specifically include a second relay J2, a third relay J3, and a trigger signal relay JR1, where the second relay J2 includes two channels, an input terminal IN1 of the first channel is connected to a live line terminal L of the input power source, and a normally closed contact H1 of the first channel is connected to the live line L; an input end IN2 of the second channel is connected with a zero line end N of an input power supply, a normally closed contact H2 of the second channel is connected with the zero line N, and a normally open contact S2 of the second channel is connected with one control end of a trigger signal relay JR1, a normally open contact S of a first relay J1 and one control end of a second relay J2; the other control end of the second relay J2 is connected with the input end IN of the third relay J3;

a normally closed contact H of the third relay J3 is connected with a live wire end L of an input power supply, one control end is connected with a working voltage VCC, and the other control end receives a recovery control signal RE;

the other control end of the trigger signal relay JR1 is connected to the live wire end L of the input power supply, the input end IN thereof is connected to the working voltage VCC, and the normally open contact S thereof serves as the delay control signal output end for outputting the delay control signal Pu, which is the high level of the working voltage VCC.

Since the normally closed contact H of the third relay J3 is connected to the live line terminal L of the input power source, the other control terminal of the second relay J2 is connected to the input terminal of the third relay J3, that is, the other control terminal of the second relay J2 is communicated with the live line terminal L of the input power source. Only when the third relay J3 receives the recovery control signal RE, the third relay J3 is electrically operated, and the communication between the input terminal of the third relay J3 and the normally closed contact H is disconnected, that is, the communication between the other control terminal of the second relay J2 and the live wire terminal L of the input power source is disconnected.

When the normally open contact S of the first relay J1 outputs a leakage signal, the normally open contact S of the first relay J1 is connected with the zero line end N of the input power supply, and one control end of the second relay J2 connected with the normally open contact S of the first relay J1 is communicated with the zero line end N of the input power supply. Therefore, when the normally open contact S of the first relay J1 outputs the leakage signal, the second relay J2 is electrically operated, and controls the normally open contact S1 of the first channel to communicate with the input terminal IN1, and the normally open contact S2 of the second channel to communicate with the input terminal IN 2. At this time, the live wire end L and the zero line end N of the input power supply are disconnected from the live wire L and the zero line N connected to the load, thereby realizing disconnection control of the communication path between the input power supply and the load.

When the normally open contact S of the first relay J1 outputs the leakage signal, two control ends of the trigger signal relay JR1 are respectively communicated with a fire wire end L and a zero wire end N of an input power supply, the trigger signal relay JR1 is electrified to work, the normally open contact S of the trigger signal relay JR1 is communicated with an input end IN to obtain the voltage of the working voltage VCC, and the delay control signal Pu, namely the voltage of the working voltage VCC, is generated.

Meanwhile, after the normally open contact S of the first relay J1 outputs a leakage signal, the live wire end L and the zero wire end N of the input power supply are disconnected with the live wire L and the zero wire N connected with the load under the control of the second relay J2, the live wire L and the zero wire N are not electrified, and the first relay J1 does not work any more. One control end of the trigger signal relay JR1 is connected with the normally open contact S of the first relay J1 and the normally open contact S2 of the second channel of the second relay J2 at the same time, namely, the control end of the trigger signal relay JR1 is connected with the normally open contact S2 and the normally closed contact H1 of the second channel of the second relay J2, when electric leakage is detected, the control end of the trigger signal relay JR1 can be communicated with a zero line end N of an input power supply at the front stage and the rear stage of the electric work of the second relay J2, and therefore the trigger signal relay JR1 can be in the working state all the time after the electric leakage is detected, and the delay control signal Pu is continuously output.

The delay recovery unit 400 receives the delay control signal Pu output by the line on-off control unit 200, and outputs a recovery control signal RE after a preset delay time. For example, as shown in fig. 1 and fig. 4, the delay recovering unit 400 may include a delay control module 410, where the delay control module 410 may specifically include a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a fifth capacitor C5, a first triode Q1, and an and gate chip U2, where the and gate chip U2 has at least 2 and gate channels (A1B1Y1, A2B2Y2), where two input ends A1 and B1 of the first and gate channel respectively receive a delay control signal Pu, an output end Y1 is connected with two input ends A2 and B2 of the second and gate channel, the output end Y1 is further grounded through the fifth capacitor C5, and the fourth resistor R4 is connected in parallel with the fifth capacitor C5; the output end Y2 of the second AND gate is connected with the first end of a sixth resistor R6, the second end of the sixth resistor R6 is connected with the base electrode of a first triode Q1, the base electrode of the first triode Q1 is also grounded through a fifth resistor R5, the emitter electrode of the first triode Q1 is grounded, and the collector electrode of the first triode Q1 serves as a recovery control signal output end and is used for outputting a recovery control signal RE.

After the delay control module 410 receives the delay control signal Pu, because the control signal Pu is a high level of the working voltage VCC, both the two input ends a1 and B1 of the first and gate channel of the and gate chip U2 are high levels, and the output end Y1 outputs a high level to charge the fifth capacitor C5; after a certain charging time, the voltage on the fifth capacitor C5 rises to a high level, so that the two input ends a2 and B2 of the second and gate channel are both at a high level, the output end Y2 outputs a high level, the first triode Q1 is turned on, the collector of the first triode Q1 is grounded, and the collector of the first triode Q1 outputs a low-level recovery control signal RE.

The charging time of the fifth capacitor C5 charged to the high level can be regarded as a delay time. In the embodiment shown in fig. 4, the delay control module 410 may output the recovery control signal RE after the charging time of the fifth capacitor C5. By adjusting the capacitance value of the fifth capacitor C5, the magnitude of the delay time can be adjusted. And the fourth resistor R4 is used for discharging the fifth capacitor C5.

When a control end of the third relay J3 in the on-off circuit control unit 200 receives a low-level recovery control signal RE, because another control end of the third relay J3 is connected to the working voltage VCC, the third relay J3 is powered on to work, the input end of the third relay J3 is disconnected from the normally closed contact S, a control end of the second relay J2 is no longer connected to the live wire end L of the input power supply, the second relay J2 is powered off to stop working, the normally closed contacts on the two channels of the second relay J2 are connected to the input end, and a connection path between the input power supply and the load is recovered.

In order to avoid reverse breakdown of the output end of the first and gate channel of the and gate chip U2 connected to the fifth capacitor C5 after charging to the high level, a second diode D2 may be arranged in series between the output end Y1 of the first and gate channel of the and gate chip U2 and the fifth capacitor C5, and the negative electrode of the second diode D2 is connected to the fifth capacitor C5.

In some embodiments, in order to more effectively identify the accidental leakage, the delay recovery unit 400, as shown in fig. 1, fig. 2 and fig. 5, may further include a counting module 450, where the counting module 450 may count the number of times of outputting the recovery control signal RE, and when the number of times of outputting the recovery control signal RE reaches a preset number threshold, the delay control module 410 is controlled to stop outputting the recovery control signal RE.

In some cases, the smart street lamp may have accidental leakage, which may be recovered in a short time without affecting the smart street lamp, and at this time, the delay control module 410 may be enabled to output the recovery control signal RE after the delay to attempt to recover the connection path between the input power and the load. If the leakage condition still exists, after the leakage is detected, the connection path between the input power supply and the load is disconnected, and the previous delay recovery process is continued. Considering that the recovery from the accidental leakage is generally completed in a short time, if the power failure-recovery-power failure is performed a plurality of times in succession, it can be considered that the power is not recovered as the accidental leakage.

For example, as shown in fig. 5, the counting module 450 may include a counter U3, a sixth capacitor C6, and a seventh capacitor C7, and the delay control module 410 may include a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a fifth capacitor C5, a first transistor Q1, a second transistor Q2, and an and gate chip U2; the and gate chip U2 may specifically include 4 and gate channels, where two input ends a1 and B1 of the first and gate channel receive the delay control signal Pu, an output end Y1 is connected to two input ends a2 and B2 of the second and gate channel, an output end Y1 is further grounded through a fifth capacitor C5, and a fourth resistor R4 is connected in parallel to the fifth capacitor C5; an output end Y2 of the second AND gate channel is connected with two input ends A4 and B4 of the fourth AND gate channel, an output end Y4 of the fourth AND gate channel is connected with a first end of a sixth resistor R6, a second end of the sixth resistor R6 is connected with a base electrode of a first triode Q1, the base electrode of the first triode Q1 is grounded through a fifth resistor R5, and an emitter electrode of a first triode Q1 is grounded;

a clock signal end CLK of the counter U3 is connected with a second end of a sixth resistor R6, an input end of the counter U3 is grounded, 2 output ends are connected with two input ends A3 and B3 of a third AND gate channel of the AND gate chip U2, an output end Y3 of the third AND gate channel is connected with a base electrode of a second triode Q2, the base electrode of the second triode Q2 is grounded through a seventh resistor R7, a collector electrode of the second triode Q2 is connected with a collector electrode of a first triode Q1, and an emitter electrode of the second triode Q2 serves as a recovery control signal output end and is used for outputting a recovery control signal RE; the second transistor Q2 is a PNP transistor.

After the delay control module 410 receives the delay control signal Pu, both input ends a1 and B1 of a first and gate channel of the and gate chip U2 are at high level, and an output end Y1 of the first and gate channel outputs high level to charge the fifth capacitor C5; after a certain charging time, the voltage on the fifth capacitor C5 rises to a high level, so that the two input ends a2 and B2 of the second and gate channel are both at a high level, and the output end Y2 of the second and gate channel outputs a high level; two input ends A4 and B4 of a fourth AND gate channel are also high level, an output end Y4 of the fourth AND gate channel outputs high level, a first triode Q1 is conducted, a collector of the first triode Q1 is grounded, because a second triode Q2 is a PNP type triode, when the collector does not receive voltage control, a second triode Q2 is also in a conducting state, a collector of the second triode Q2 is connected with the collector of the first triode Q1, when the collector of the first triode Q1 is grounded, an emitter of the second triode Q2 is also grounded, and an emitter of the second triode Q2 outputs a low-level recovery control signal RE.

Since the clock signal terminal CLK of the counter U3 is connected to the second terminal of the sixth resistor R6, when the emitter of the second transistor Q2 outputs the recovery control signal RE of a low level once, the second terminal of the sixth resistor R6 also transitions from the low level to the high level, so that the counter U3 can count once. When the count of the counter U3 reaches a preset time threshold, two output ends of the counter U3, which are connected with two input ends A3 and B3 of a third AND channel of the AND chip U2, output high levels. At this time, two input ends A3 and B3 of the third and channel of the and chip U2 are at a high level, and an output end Y3 of the third and channel outputs a high level, so that the second transistor Q2 is turned off, and the emitter of the second transistor Q2 stops outputting the low-level recovery control signal RE.

In the example shown in fig. 5, the and gate chip U2 may be embodied as a 74LS08 chip, and the counter U3 may be embodied as a 74LS160A chip. And connecting a second output end QB and a third output end QC of the counter U3 with two input ends A3 and B3 of a third AND gate channel of the AND gate chip U2, and setting a preset time threshold value to be 6. It is understood that the preset times threshold of different values can be set by adjusting the output terminals of the counter U3 connected to the two input terminals of the third and channel of the and chip U2.

In some embodiments, the counting module 450 may further include a reset key K1, and the reset terminal of the counter U3 is grounded through the reset key K1. When the reset key K1 is pressed, the reset terminal of the counter U3 is grounded, and the count in the counter U3 is cleared.

In some embodiments, the delay recovery unit 400 may further include an alarm 480, and a port of the alarm 480 is connected to the base of the second transistor Q2, so that when the count of the counter U3 reaches a preset threshold number of times, the alarm 480 may be triggered synchronously to give an alarm.

The utility model discloses another embodiment still provides a wisdom street lamp, includes the leakage protection circuit that can independently resume in the arbitrary embodiment in the preceding.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An electric leakage protection circuit capable of automatically recovering is characterized by comprising an electric leakage detection unit, a circuit on-off control unit, a working voltage generation unit and a time delay recovery unit;

2. The earth leakage protection circuit of claim 1, wherein the input power source comprises a live end and a neutral end, and the power line to the load comprises a live and neutral line; the leakage detection unit comprises a mutual inductor, a first rectifier bridge, a silicon controlled rectifier, a first resistor, a first capacitor and a first relay, wherein the mutual inductor comprises a magnetic ring and a winding wound on the magnetic ring, a line of a live wire and a zero line penetrates through the mutual inductor, and the first resistor and the first capacitor are arranged between two ends of the winding in parallel; one end of the winding is connected with the direct-current output negative end of the first rectifier bridge and the negative electrode of the controlled silicon, the other end of the winding is connected with the control electrode of the controlled silicon, and the direct-current output positive end of the first rectifier bridge is connected with the anode of the controlled silicon; one alternating current input end of the first rectifier bridge and the input end of the first relay are connected with one of the live wire and the zero wire; the other alternating current input end of the first rectifier bridge is connected with one control end of the first relay; the other control end of the first relay is connected with the other of the live wire and the zero wire, and the normally open contact of the first relay is used as the output end of the leakage signal.

3. The earth leakage protection circuit according to claim 1, wherein the operating voltage generating unit comprises a second capacitor, a third capacitor, a second resistor, a third resistor, a second rectifier bridge and a voltage regulator tube, wherein an ac input end of the second rectifier bridge is connected to one of a live wire end and a neutral wire end of an input power supply through the second capacitor; the other alternating current input end of the second rectifier bridge is connected with the other of the live wire end and the zero wire end of the input power supply; the second resistor and the third resistor are connected in series to form a discharge branch, and the discharge branch is connected with the second capacitor in parallel; the third capacitor and the voltage-stabilizing tube are arranged in parallel between the direct-current output positive end and the direct-current output negative end of the second rectifier bridge, the direct-current output negative end of the second rectifier bridge is grounded, and the direct-current output positive end outputs working voltage.

4. The leakage protection circuit of claim 3, wherein the operating voltage generating unit further comprises a fourth capacitor and a three-terminal regulator chip, an input terminal of the three-terminal regulator chip is connected to the positive terminal of the direct current output of the second rectifier bridge, and a ground terminal of the three-terminal regulator chip is grounded; and two ends of the fourth capacitor are respectively connected with the output end and the grounding end of the three-terminal voltage stabilizing chip, and the output end of the three-terminal voltage stabilizing chip outputs working voltage.

5. The earth leakage protection circuit of claim 2, wherein the on-off line control unit comprises a second relay, a third relay, and a trigger signal relay; the second relay comprises a first channel and a second channel, the input end of the first channel is connected with a live wire end of an input power supply, the normally closed contact of the first channel is connected with a live wire, the input end of the second channel is connected with a zero wire end of the input power supply, the normally closed contact of the second channel is connected with a zero wire, and the normally open contact of the second channel is connected with one control end of the trigger signal relay, the normally open contact of the first relay and one control end of the second relay; the other control end of the second relay is connected with the input end of the third relay;

6. The earth leakage protection circuit of claim 1, wherein the delay recovery unit comprises a delay control module, the delay control module comprises a fourth resistor, a fifth resistor, a sixth resistor, a fifth capacitor, a first triode, and an and gate chip, the and gate chip has at least 2 and gate channels, wherein two input ends of the first and gate channel respectively receive the delay control signal, an output end of the first and gate channel is connected with two input ends of the second and gate channel, an output end of the first and gate channel is further grounded through the fifth capacitor, and the fourth resistor is connected in parallel with the fifth capacitor; the output end of the second and gate channel is connected with the first end of the sixth resistor, the second end of the sixth resistor is connected with the base electrode of the first triode, the base electrode of the first triode is grounded through the fifth resistor, the emitting electrode of the first triode is grounded, and the collecting electrode of the first triode is used as the output end of the recovery control signal and used for outputting the recovery control signal.

7. The earth leakage protection circuit of claim 1, wherein the delay recovery unit comprises a delay control module and a counting module; the counting module comprises a counter, a sixth capacitor and a seventh capacitor, and the delay control module comprises a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a fifth capacitor, a first triode, a second triode and an AND gate chip; the AND gate chip comprises 4 AND gate channels, two input ends of a first AND gate channel receive the delay control signal, an output end of the first AND gate channel is connected with two input ends of a second AND gate channel, an output end of the first AND gate channel is grounded through a fifth capacitor, and a fourth resistor is connected with the fifth capacitor in parallel; the output end of the second and gate channel is connected with two input ends of a fourth and gate channel, the output end of the fourth and gate channel is connected with the first end of a sixth resistor, the second end of the sixth resistor is connected with the base electrode of the first triode, the base electrode of the first triode is grounded through the fifth resistor, and the emitting electrode of the first triode is grounded;

8. The earth leakage protection circuit of claim 7, wherein the counting module further comprises a reset button, and a reset terminal of the counter is grounded through the reset button; when the reset key is pressed down, the reset end of the counter is grounded, and the counting in the counter is cleared.

9. The leakage protection circuit of claim 7, wherein the delay recovery unit further comprises an alarm, and a port of the alarm is connected to the base of the second transistor; and when the counting of the counter reaches a preset time threshold value, the alarm is synchronously triggered to warn.

10. An intelligent street lamp having the self-recoverable leakage protection circuit according to any one of claims 1 to 9.