CN104377647A - Electric leakage protection circuit - Google Patents
Electric leakage protection circuit Download PDFInfo
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- CN104377647A CN104377647A CN201410707631.7A CN201410707631A CN104377647A CN 104377647 A CN104377647 A CN 104377647A CN 201410707631 A CN201410707631 A CN 201410707631A CN 104377647 A CN104377647 A CN 104377647A
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Abstract
The invention provides an electric leakage protection circuit. The electric leakage protection circuit comprises an electric leakage detecting unit, a first circuit and a switch control circuit. The electric leakage detecting unit is used for detecting whether electric leakage exists in the circuit or not and outputting electric leakage signals during electric leakage. The first circuit comprises a control switch, a voltage divider and a protector, wherein the control switch is serially connected with the protector after connected with the voltage divider in parallel. The first circuit cuts off a power supply circuit through the protector when receiving the electric leakage signals, the switch control circuit cuts off the control switch when the current in the first circuit is larger than or equal to the preset value, so that the current flowing the voltage divider is subjected to voltage dividing, and the control switch is conducted when the current is smaller than the preset value. When the first circuit is overlarge in current, the voltage divider is serially connected into the first circuit for voltage dividing, current flowing through the protector is lowered, high impact on an executing mechanism matched with the protector is avoided when the current is overlarge, and electrical life of an electric leakage protection breaker is prolonged. Besides, when the first circuit is low in current, the voltage divider is in short circuit, and sufficient current of the protector is ensured so as to cut off a power source at a malfunction position.
Description
Technical field
The present invention relates to electric leakage protection technology field.Relate in particular to a kind of leakage protection circuit.
Background technology
Establishing earth leakage protective device to be one of effective measures preventing accident of human electric shock in low-voltage distribution system, is also prevent because electric leakage causes one of technical measures of electrical fire and electric equipment damage accident.
Common earth leakage protective device has earth leakage protective device, circuit breaker etc.In prior art, when load on-line operation, detecting element can be passed through, such as instrument transformer comes whether have leak current fault in testing circuit, in embody rule, the live wire of a certain phase line, zero line pass the magnet ring of instrument transformer, and constitute the primary winding of instrument transformer, the winding be wrapped on magnet ring constitutes the second siding ring of instrument transformer.If do not leak electricity generation, at this moment flow through live wire, zero line current vector and equal zero, therefore on the second siding ring of instrument transformer, also can not produce corresponding induced electromotive force.And if there occurs electric leakage, then live wire, zero line current vector and be not equal to zero, will make the second siding ring of instrument transformer produces induced electromotive force, and trigger actuator, such as the power supply at release dropout disengagement failure place.
At present, at home in low voltage electrical apparatus industry, the mode of single tripping coil work that what the leakage protection circuit in common electronic leakage protective circuit breaker generally adopted is, according to different needs, be divided into discrete earth leakage circuit breaker and integrated form earth leakage circuit breaker, Fig. 1 is the circuit theory diagrams of the leakage protection circuit of discrete earth leakage circuit breaker, the signal that instrument transformer exports is used for directly triggering controllable silicon D5 after simple resistance capacitance process, after controllable silicon D5 conducting, at live wire A, tripping coil Coil, rectifier bridge, loop is formed between controllable silicon D5 and zero line N, electric current is had to flow through tripping coil Coil, making it produce the suction-combining force makes hasp and snap close throw off, by main contact disjunction, disengagement failure place power supply is to realize earth leakage protective function, Fig. 2 is the circuit theory diagrams of the leakage protection circuit of integrated form earth leakage circuit breaker, and employing integrated chip processes the electric leakage signal that instrument transformer second siding ring detects exactly.
But be no matter the earth leakage circuit breaker of discrete or integrated form, in order to ensure that earth leakage circuit breaker normally works under interchange 50V ~ 230V operating voltage, tripping coil used must meet and can normally work under interchange 50V voltage, but, in real work circuit, normal power supply voltage is 230V, its voltage has exceeded 4 times of the normal working voltage of tripping coil Coil used, release works when exceeding normal working voltage for a long time, the electric current flowing through release is larger, considerably increase the tripping force of tripping coil Coil, this can cause larger impact to the actuator coordinated with it, produce unnecessary damage, in addition, single tripping coil Coil works and can reduce its useful life because of heating under long-term big current, increase the possibility that it damages.
Summary of the invention
For this reason; the mode of single tripping coil work that what technical problem to be solved by this invention was that leakage protection circuit of the prior art generally adopts is; release works when exceeding normal working voltage for a long time; make the electric current flowing through release larger; cause the tripping force of tripping coil excessive; larger impact is caused to the actuator coordinated with it; create unnecessary damage; reduce the electrical endurance of earth leakage circuit breaker, thus a kind of leakage protection circuit that can strengthen earth leakage circuit breaker electrical endurance is provided.
For solving the problems of the technologies described above, technical scheme of the present invention is as follows:
The invention provides a kind of leakage protection circuit, comprising:
Detection of electrical leakage unit, for whether leaking electricity in testing circuit, and exports electric leakage signal when there is electric leakage;
First loop, comprises control switch, voltage divider and protector, connects after described control switch and described voltage divider parallel connection with described protector; Described first loop cuts off supply line when receiving described electric leakage signal by described protector;
ON-OFF control circuit, disconnects described control switch when the electric current in described first loop is more than or equal to preset value, makes described electric current flow through described voltage divider and carries out dividing potential drop; Control switch described in conducting when electric current in described first loop is less than described preset value.
Leakage protection circuit of the present invention, described detection of electrical leakage unit comprises instrument transformer, the first voltage-stabiliser tube Z3, the first electric capacity C5, the first resistance R8 and the second resistance R9;
Described instrument transformer comprises magnet ring and is wrapped in the winding on described magnet ring, live wire and zero line pass from described magnet ring, one end of described winding and the negative electrode of described first voltage-stabiliser tube Z3 couple, the other end of described winding and the anode of described first voltage-stabiliser tube Z3 couple, one end of described first electric capacity C5 couples with the negative electrode of described first voltage-stabiliser tube Z3 after described first resistance R8, the other end of described first electric capacity C5 couples with the anode of described first voltage-stabiliser tube Z3 after described second resistance R9, one end that described first electric capacity C5 and described first resistance R8 couples is the electric leakage signal output of described detection of electrical leakage unit, for exporting described electric leakage signal.
Leakage protection circuit of the present invention, described protector 23 is first tripping coil Coil.
Leakage protection circuit of the present invention, described first loop also comprises the first controllable silicon D8, the bridge circuit be made up of the first diode D1, the second diode D2, the 3rd diode D3 and the 4th diode D4 and the first piezo-resistance MYR1;
The positive pole of described first diode D1 is connected the first end as bridge circuit with the negative pole of described 3rd diode D3, the positive pole of described second diode D2 is connected the second end as bridge circuit with the negative pole of described 4th diode D4, the negative pole of described first diode D1 is connected the 3rd end as bridge circuit with the negative pole of described second diode D2, the positive pole of described 3rd diode D3 is connected the 4th end as bridge circuit with the positive pole of described 4th diode D4;
The control pole of described first controllable silicon D8 and the electric leakage signal output of described detection of electrical leakage unit couple, the positive pole of described first controllable silicon D8 and the 3rd end of described bridge circuit couple, the negative pole of described first controllable silicon D8 and the 4th end of described bridge circuit couple, one end and the described live wire of described first tripping coil Coil couple, the other end of described first tripping coil Coil couples with described zero line after described first piezo-resistance MYR1, and the two ends of described first piezo-resistance MYR1 couple with the first end of described bridge circuit and the second end respectively.
Leakage protection circuit of the present invention, described control switch comprises the second controllable silicon D6 and the 5th diode D7;
It is in parallel with described voltage divider after described second controllable silicon D6 and described 5th diode D7 connects;
The positive pole of described second controllable silicon D6 and the 3rd end of described bridge circuit couple, the negative pole of described second controllable silicon D6 and the positive pole of described 5th diode D7 couple, the negative pole of described 5th diode D7 and the positive pole of described first controllable silicon D8 couple, and the described control pole of the second controllable silicon D6 and the voltage output end of described ON-OFF control circuit couple.
Leakage protection circuit of the present invention, described voltage divider is coil N.
Leakage protection circuit of the present invention, described first loop also comprises discharger, with described coil N parallel, discharges to described coil N for the moment in described coil N power-off.
Leakage protection circuit of the present invention; described discharger comprises the 6th diode D5; one end that negative pole and the described coil N of described 6th diode D5 are connected with the positive pole of described second controllable silicon D6 couples, and one end that positive pole and the described coil N of described 6th diode D5 are connected with the negative pole of described 5th diode D7 couples.
Leakage protection circuit of the present invention, described ON-OFF control circuit comprises comparator U1, the 3rd resistance R1, the 4th resistance R2 and the second electric capacity C1;
Described comparator U1 comprises first input end, the second input and an output;
Described 4th resistance R2 is in parallel with described second electric capacity C1, one end of described 3rd resistance R1 and the 3rd end of described bridge circuit couple, the other end of described 3rd resistance R1 couples with described 4th resistance R2 and a common port of described second electric capacity C1 and the first input end of described comparator U1 simultaneously, another common end grounding of described 4th resistance R2 and described second electric capacity C1, the second input termination predeterminated voltage V2 of described comparator U1, the output of described comparator U1 is the voltage output end of described ON-OFF control circuit, couple with the control pole of described second controllable silicon D6,
When the electric current in described first loop is more than or equal to preset value, the voltage at the first input end place of described comparator U1 is more than or equal to the predeterminated voltage V2 of second input end of described comparator U1, the output output low level of described comparator U1; When the electric current in described first loop is less than preset value, the voltage at the first input end place of described comparator U1 is less than the predeterminated voltage V2 of second input end of described comparator U1, and the output of described comparator U1 exports high level.
Leakage protection circuit of the present invention, described ON-OFF control circuit also comprises voltage provides electronic circuit, and described voltage provides electronic circuit to comprise the first voltage-stabiliser tube Z1, the second voltage-stabiliser tube Z2 and the 7th resistance R7;
It is in parallel with described first voltage-stabiliser tube Z1 after described 7th resistance R7 connects with described second voltage-stabiliser tube Z2, couple with the 4th end of described bridge circuit after the positive pole of described second voltage-stabiliser tube Z2 is connected with the positive pole of described first voltage-stabiliser tube Z1, couple with the positive pole of described first controllable silicon D8 after described 7th resistance R7 is connected with the negative pole of described first voltage-stabiliser tube Z1, one end that described 7th resistance R7 is connected with the negative pole of described first voltage-stabiliser tube Z1 is used for providing direct voltage to described comparator U1, the common port of described 7th resistance R7 and described second voltage-stabiliser tube Z2 is for exporting described predeterminated voltage V2.
Technique scheme of the present invention has the following advantages compared to existing technology:
The invention provides a kind of leakage protection circuit, comprise detection of electrical leakage unit, for whether leaking electricity in testing circuit, and export electric leakage signal when there is electric leakage, first loop, comprise control switch, voltage divider and protector, connect with protector after control switch and voltage divider parallel connection, first loop cuts off supply line when receiving electric leakage signal by protector, ON-OFF control circuit electric current in the first loop disconnects control switch when being more than or equal to preset value, make electric current flow through voltage divider and carry out dividing potential drop, the conducting control switch when electric current is less than preset value.Also namely when the first loop current is excessive, voltage divider is connected and carries out dividing potential drop into the first loop, reduce the electric current flowing through protector, avoid the excessive greater impact that the actuator be mated is caused of protector electric current, and the phenomenon of the reduction in useful life caused because of heating that works under the long-term big current of protector, enhance the electrical endurance of earth leakage circuit breaker; When the first loop current is less, again can short circuit voltage divider, guarantee that protector has enough electric currents to flow through with the power supply at open failure place, ensure that the smooth realization of creepage protection function.
Accompanying drawing explanation
In order to make content of the present invention be more likely to be clearly understood, below according to a particular embodiment of the invention and by reference to the accompanying drawings, the present invention is further detailed explanation, wherein
Fig. 1 is the circuit theory diagrams of discrete leakage protection circuit in prior art;
Fig. 2 is the circuit theory diagrams of integrated form leakage protection circuit in prior art;
Fig. 3 is the structured flowchart of leakage protection circuit of the present invention;
Fig. 4 is the circuit theory diagrams of leakage protection circuit of the present invention.
In figure, Reference numeral is expressed as: 1-detection of electrical leakage unit, 2-first loop, 3-ON-OFF control circuit, 4-power consumption equipment; 5-actuator, 6-power supply, 11-instrument transformer, 21-control switch; 22-voltage divider, 23-protector, 24-discharger, 34-voltage provides electronic circuit.
Embodiment
Present embodiments provide a kind of leakage protection circuit, as shown in Figure 3, comprising:
Detection of electrical leakage unit 1, for whether leaking electricity in testing circuit, and exports electric leakage signal when there is electric leakage;
First loop 2, comprises control switch 21, voltage divider 22 and protector 23, connects after described control switch 21 and described voltage divider 22 parallel connection with described protector 23; Described first loop 2 cuts off supply line when receiving described electric leakage signal by described protector 23;
ON-OFF control circuit 3, disconnects described control switch 21 when the electric current in described first loop 2 is more than or equal to preset value, makes described electric current flow through described voltage divider 22 and carries out dividing potential drop; Control switch 21 described in conducting when electric current in described first loop 2 is less than described preset value.
Particularly; after such as detection of electrical leakage unit 1 detects that power consumption equipment 4 leaks electricity; electric leakage signal to the first loop 2 can be exported; first loop 2 is after receiving electric leakage signal; protector 23 in first loop 2 can control actuator 5 action; disconnect the power supply 6 at power consumption equipment 4 place that electric leakage occurs, get an electric shock after preventing operating personnel from touching the metal shell of power consumption equipment 4.In prior art; produce enough strength in order to ensure protector 23 and control actuator 5 action; the current ratio flowing through protector 23 generally can be made larger; also the current ratio namely in the first loop 2 is larger; but protector 23 works for a long time under big current, easily heating reduces useful life; the excessive impact that protector 23 also can be made to cause the actuator 5 be mated of electric current separately flowing through protector 23 is comparatively large, causes actuator 5 to damage.
When electric current in the first loop 2 is more than or equal to preset value, ON-OFF control circuit 3 can control control switch 21 and disconnect, now voltage divider 22 drops into the first loop 2 and carries out dividing potential drop, electric current in first loop 2 is reduced, the electric current flowing through protector 23 also can reduce naturally, reduce its impact to actuator 5, extend the useful life of protector 23 and actuator 5; When electric current in the first loop 2 is less than preset value, ON-OFF control circuit 3 meeting conducting control switch 21, now voltage divider 22 is by control switch 21 short circuit, cuts out the first loop 2, makes protector 23 flow through enough large electric current and makes actuator 5 action.Therefore; leakage protection circuit described in the present embodiment is guaranteeing that protector 23 controls actuator 5 open failure place power supply with while realizing creepage protection function when there is electric leakage; the electric current flowing through protector 23 can also be reduced as far as possible; prevent it from producing excessive impact to actuator 5, extend its electrical endurance.
Preferably, as shown in Figure 4, described detection of electrical leakage unit 1 can comprise instrument transformer 11, first voltage-stabiliser tube Z3, the first electric capacity C5, the first resistance R8 and the second resistance R9;
Described instrument transformer 11 comprises magnet ring and is wrapped in the winding on described magnet ring, live wire and zero line pass from described magnet ring, one end of described winding and the negative electrode of described first voltage-stabiliser tube Z3 couple, the other end of described winding and the anode of described first voltage-stabiliser tube Z3 couple, one end of described first electric capacity C5 couples with the negative electrode of described first voltage-stabiliser tube Z3 after described first resistance R8, the other end of described first electric capacity C5 couples with the anode of described first voltage-stabiliser tube Z3 after described second resistance R9, one end that described first electric capacity C5 and described first resistance R8 couples is the electric leakage signal output of described detection of electrical leakage unit 1, for exporting described electric leakage signal.
Particularly, when there is leak current fault in circuit, the vector flowing into the electric current of instrument transformer 11 magnet ring and the electric current of outflow instrument transformer 11 magnet ring is non-vanishing, the winding two ends of instrument transformer 11 will produce induced electromotive force, dividing potential drop through the first voltage-stabiliser tube Z3 voltage stabilizing amplitude limit and the first resistance R8 and the second resistance R9 is after-applied on the first electric capacity C5, namely the voltage of one end that the first electric capacity C5 and the first resistance R8 couples can be used as electric leakage signal, and one end that corresponding first electric capacity C2 and the first resistance R4 couples is the electric leakage signal output of detection of electrical leakage unit 1.First resistance R8 is connected can carries out filtering with the first electric capacity C5, filters out the interference in electric leakage signal.
Preferably, as shown in Figure 4, described protector 23 can be the first tripping coil Coil.
Preferably, as shown in Figure 4, described first loop 2 can also comprise the first controllable silicon D8, the bridge circuit be made up of the first diode D1, the second diode D2, the 3rd diode D3 and the 4th diode D4 and the first piezo-resistance MYR1;
The positive pole of described first diode D1 is connected the first end as bridge circuit with the negative pole of described 3rd diode D3, the positive pole of described second diode D2 is connected the second end as bridge circuit with the negative pole of described 4th diode D4, the negative pole of described first diode D1 is connected the 3rd end as bridge circuit with the negative pole of described second diode D2, the positive pole of described 3rd diode D3 is connected the 4th end as bridge circuit with the positive pole of described 4th diode D4;
The control pole of described first controllable silicon D8 and the electric leakage signal output of described detection of electrical leakage unit 1 couple, the positive pole of described first controllable silicon D8 and the 3rd end of described bridge circuit couple, the negative pole of described first controllable silicon D8 and the 4th end of described bridge circuit couple, one end and the described live wire of described first tripping coil Coil couple, the other end of described first tripping coil Coil couples with described zero line after described first piezo-resistance MYR1, and the two ends of described first piezo-resistance MYR1 couple with the first end of described bridge circuit and the second end respectively.
Particularly, alternating current between live wire and zero line can apply a forward voltage to the positive pole of the first controllable silicon D8 after bridge circuit rectification, because the control pole of the first controllable silicon D8 and the electric leakage signal output of detection of electrical leakage unit 1 couple, be and be electrically connected with the common port between the first electric capacity C5 with the first resistance R8, the induced electromotive force produced when detection of electrical leakage unit 1 is enough large, also namely electric leakage signal is enough strong, when reaching the trigger voltage of the control pole of the first controllable silicon D8, will triggering and conducting first controllable silicon D8, and after the first controllable silicon D8 conducting, live wire A, first tripping coil Coil, bridge circuit, first controllable silicon D8, the loop of a conducting will be formed between zero line N, also i.e. the first loop 2 conducting, now have electric current and flow through the first tripping coil Coil, making it produce the suction-combining force makes hasp and snap close throw off, by main contact disjunction, disengagement failure place power supply is to realize earth leakage protective function.And the first tripping coil Coil and the first piezo-resistance MYR1 is in series, can absorb surge, holding circuit is stablized.
Preferably, as shown in Figure 4, described control switch 21 can comprise the second controllable silicon D6 and the 5th diode D7;
It is in parallel with described voltage divider 22 after described second controllable silicon D6 and described 5th diode D7 connects;
The positive pole of described second controllable silicon D6 and the 3rd end of described bridge circuit couple, the negative pole of described second controllable silicon D6 and the positive pole of described 5th diode D7 couple, the negative pole of described 5th diode D7 and the positive pole of described first controllable silicon D8 couple, and the described control pole of the second controllable silicon D6 and the voltage output end of described ON-OFF control circuit 3 couple.
Particularly, when electric current in the first loop 2 is more than or equal to preset value, ON-OFF control circuit 3 is to the control pole output low level of the second controllable silicon D6, lower than the trigger voltage of the second controllable silicon D6, make it end, and the second controllable silicon D6 ends, also namely control switch 21 disconnects, make voltage divider 22 drop into the first loop 2 and carry out dividing potential drop, reduce the electric current in the first loop 2; When electric current in the first loop 2 is less than preset value, ON-OFF control circuit 3 exports high level to the control pole of the second controllable silicon D6, higher than the trigger voltage of the second controllable silicon D6, make its conducting, electric current now in circuit directly returns zero line N after the second controllable silicon D6, the 5th diode D7, the first controllable silicon D8, rectifier bridge, voltage divider 22, by short circuit, cuts out the first loop 2.
Preferably, as shown in Figure 4, described voltage divider 22 can be coil N.
Particularly, leakage protection circuit in the present embodiment, the current conditions in the first loop 2 is detected by ON-OFF control circuit 3, and control being turned on or off of control switch 21 according to current conditions, the startup achieving unicoil and twin coil two kinds of working methods switches, and unicoil (the first tripping coil Coil) work under utilizing low current, the mechanism of action of two coil (the first tripping coil Coil and coil N) dividing potential drops of connecting under high electric current, reach the object reducing and flow through the electric current of the first tripping coil Coil, reduce tripping force when it is threaded off, prevent it to the excessive damage brought of actuator's impulsive force (the suction-combining force), enhance the electrical endurance of product.
Preferably, as shown in Figure 3, Figure 4, described first loop 2 can also comprise discharger 24, with described coil N parallel, discharges to described coil N for the moment in described coil N power-off.
Preferably, as shown in Figure 4, described discharger 24 can comprise the 6th diode D5, one end that negative pole and the described coil N of described 6th diode D5 are connected with the positive pole of described second controllable silicon D6 couples, and one end that positive pole and the described coil N of described 6th diode D5 are connected with the negative pole of described 5th diode D7 couples.
Particularly, when the moment of the second controllable silicon D6 conducting, coil N is by short circuit, now coil N can discharge in the moment of power-off, if do not have increase the 6th diode D5, the electricity that coil N releases likely can reverse breakdown second controllable silicon D6 and the 5th diode D7, by increasing by the 6th diode D5, a discharge loop can be formed between coil N and the 6th diode D5, prevent the second controllable silicon D6 and the 5th diode D7 to be reversed and puncture.
Preferably, as shown in Figure 4, described ON-OFF control circuit 3 can comprise comparator U1, the 3rd resistance R1, the 4th resistance R2 and the second electric capacity C1;
Described comparator U1 comprises first input end, the second input and an output;
Described 4th resistance R2 is in parallel with described second electric capacity C1, one end of described 3rd resistance R1 and the 3rd end of described bridge circuit couple, the other end of described 3rd resistance R1 couples with described 4th resistance R2 and a common port of described second electric capacity C1 and the first input end of described comparator U1 simultaneously, another common end grounding of described 4th resistance R2 and described second electric capacity C1, the second input termination predeterminated voltage V2 of described comparator U1, the output of described comparator U1 is the voltage output end of described ON-OFF control circuit 3, couple with the control pole of described second controllable silicon D6,
When the electric current in described first loop 2 is more than or equal to preset value, the voltage at the first input end place of described comparator U1 is more than or equal to the predeterminated voltage V2 of second input end of described comparator U1, the output output low level of described comparator U1; When the electric current in described first loop 2 is less than preset value, the voltage at the first input end place of described comparator U1 is less than the predeterminated voltage V2 of second input end of described comparator U1, and the output of described comparator U1 exports high level.
Particularly, described comparator U1 can select voltage comparator chip, according to the characteristic of voltage comparator chip, when just (+) input terminal voltage is higher than negative (-) input terminal voltage for it, the output of voltage comparator chip exports as high level, when just (+) input terminal voltage is lower than negative (-) input terminal voltage for it, the output of voltage comparator chip exports as low level.The value of predeterminated voltage V2 can be determined according to the resistance of the preset value of the electric current in the first loop 2 and the 3rd resistance R1, the 4th resistance R2.
In the present embodiment, the first input end (pin 2 place) of comparator U1 is negative input end, and second input (pin 3 place) of comparator U1 is positive input terminal.When the electric current in the first loop 2 is more than or equal to preset value, the electric current flowing through the 6th resistance R5 also can be larger, make the voltage on the 6th resistance R5 also can be larger, now the voltage at first input end (pin 2) place of comparator U1 will be more than or equal to the predeterminated voltage V2 at the second input (pin 3) place of comparator U1, also namely just (+) input terminal voltage lower than negative (-) input terminal voltage, output (pin 1) place of comparator U1 will output low level, second controllable silicon D6 ends, make coil N drop into the first loop 2 and carry out dividing potential drop, electric current in first loop 2 is reduced, when the electric current in the first loop 2 is less than preset value, the electric current flowing through the 6th resistance R5 also can be smaller, make the voltage on the 6th resistance R5 also can be smaller, now the voltage at first input end (pin 2) place of comparator U1 will be less than the predeterminated voltage V2 at the second input (pin 3) place of comparator U1, also namely just (+) input terminal voltage higher than negative (-) input terminal voltage, output (pin 1) place of comparator U1 will export high level, second controllable silicon D6 conducting, makes coil N cut out the first loop 2.
Particularly, in order to the voltage signal intensity that the output strengthening comparator U1 exports, it is made to be enough to conducting second controllable silicon D6 when exporting high level, pull-up circuit can be added at the output of comparator U1, as shown in Figure 4, namely 5th resistance R4 and the 6th resistance R5 constitutes above-mentioned pull-up circuit, concrete annexation is a termination direct voltage V1 of the 5th resistance R4, the other end of described 5th resistance R4 and one end of described 6th resistance R5 couple, the other end ground connection of described 6th resistance R5, the common port of described 5th resistance R4 and described 6th resistance R5 and the output of described comparator U1 couple.
Preferably, described ON-OFF control circuit 3 can also comprise voltage provides electronic circuit 34, and described voltage provides electronic circuit 34 can comprise the first voltage-stabiliser tube Z1, the second voltage-stabiliser tube Z2 and the 7th resistance R7;
It is in parallel with described first voltage-stabiliser tube Z1 after described 7th resistance R7 connects with described second voltage-stabiliser tube Z2, couple with the 4th end of described bridge circuit after the positive pole of described second voltage-stabiliser tube Z2 is connected with the positive pole of described first voltage-stabiliser tube Z1, couple with the positive pole of described first controllable silicon D8 after described 7th resistance R7 is connected with the negative pole of described first voltage-stabiliser tube Z1, one end that described 7th resistance R7 is connected with the negative pole of described first voltage-stabiliser tube Z1 is used for providing direct voltage V1 to described comparator U1, the common port of described 7th resistance R7 and described second voltage-stabiliser tube Z2 is for exporting described predeterminated voltage V2.
Particularly, by the pressure stabilization function of the first voltage-stabiliser tube Z1 and the second voltage-stabiliser tube Z2, galvanic current can be provided to press V1 and predeterminated voltage V2 to comparator U1, control more accurate.
Leakage protection circuit described in the present embodiment, when the first loop 2 electric current is excessive, voltage divider 22 is connected and carries out dividing potential drop into the first loop 2, reduce the electric current flowing through protector 23, avoid the excessive greater impact that the actuator 5 be mated is caused of protector 23 electric current, and the phenomenon of the reduction in useful life caused because of heating that works under the long-term big current of protector 23, enhance the electrical endurance of earth leakage circuit breaker; When the first loop 2 electric current is less, again can short circuit voltage divider 22, guarantee that protector 23 has enough electric currents to flow through with the power supply at open failure place, ensure that the smooth realization of creepage protection function.
Obviously, above-described embodiment is only for clearly example being described, and the restriction not to execution mode.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without the need to also giving all execution modes.And thus the apparent change of extending out or variation be still among the protection range of the invention.
Claims (10)
1. a leakage protection circuit, is characterized in that, comprising:
Detection of electrical leakage unit (1), for whether leaking electricity in testing circuit, and exports electric leakage signal when there is electric leakage;
First loop (2), comprise control switch (21), voltage divider (22) and protector (23), connect with described protector (23) after described control switch (21) and described voltage divider (22) parallel connection, described first loop (2) cuts off supply line when receiving described electric leakage signal by described protector (23);
ON-OFF control circuit (3), disconnects described control switch (21) when the electric current in described first loop (2) is more than or equal to preset value, makes described electric current flow through described voltage divider (22) and carries out dividing potential drop; Control switch (21) described in conducting when electric current in described first loop (2) is less than described preset value.
2. leakage protection circuit according to claim 1, it is characterized in that, described detection of electrical leakage unit (1) comprises instrument transformer (11), the first voltage-stabiliser tube (Z3), the first electric capacity (C5), the first resistance (R8) and the second resistance (R9);
Described instrument transformer (11) comprises magnet ring and is wrapped in the winding on described magnet ring, live wire and zero line pass from described magnet ring, one end of described winding and the negative electrode of described first voltage-stabiliser tube (Z3) couple, the other end of described winding and the anode of described first voltage-stabiliser tube (Z3) couple, one end of described first electric capacity (C5) couples with the negative electrode of described first voltage-stabiliser tube (Z3) after described first resistance (R8), the other end of described first electric capacity (C5) couples with the anode of described first voltage-stabiliser tube (Z3) after described second resistance (R9), one end that described first electric capacity (C5) and described first resistance (R8) couple is the electric leakage signal output of described detection of electrical leakage unit (1), for exporting described electric leakage signal.
3. leakage protection circuit according to claim 1, is characterized in that, described protector (23) is the first tripping coil (Coil).
4. leakage protection circuit according to claim 3, it is characterized in that, described first loop (2) also comprises the first controllable silicon (D8), the bridge circuit be made up of the first diode (D1), the second diode (D2), the 3rd diode (D3) and the 4th diode (D4) and the first piezo-resistance (MYR1);
The positive pole of described first diode (D1) is connected the first end as bridge circuit with the negative pole of described 3rd diode (D3), the positive pole of described second diode (D2) is connected the second end as bridge circuit with the negative pole of described 4th diode (D4), the negative pole of described first diode (D1) is connected the 3rd end as bridge circuit with the negative pole of described second diode (D2), the positive pole of described 3rd diode (D3) is connected the 4th end as bridge circuit with the positive pole of described 4th diode (D4);
The control pole of described first controllable silicon (D8) and the electric leakage signal output of described detection of electrical leakage unit (1) couple, the positive pole of described first controllable silicon (D8) and the 3rd end of described bridge circuit couple, the negative pole of described first controllable silicon (D8) and the 4th end of described bridge circuit couple, one end and the described live wire of described first tripping coil (Coil) couple, the other end of described first tripping coil (Coil) couples with described zero line after described first piezo-resistance (MYR1), the two ends of described first piezo-resistance (MYR1) couple with the first end of described bridge circuit and the second end respectively.
5. leakage protection circuit according to claim 4, is characterized in that, described control switch (21) comprises the second controllable silicon (D6) and the 5th diode (D7);
Described second controllable silicon (D6) and described 5th diode (D7) are in parallel with described voltage divider (22) after connecting;
The positive pole of described second controllable silicon (D6) and the 3rd end of described bridge circuit couple, the negative pole of described second controllable silicon (D6) and the positive pole of described 5th diode (D7) couple, the described negative pole of the 5th diode (D7) and the positive pole of described first controllable silicon (D8) couple, and the control pole of described second controllable silicon (D6) and the voltage output end of described ON-OFF control circuit (3) couple.
6. leakage protection circuit according to claim 5, is characterized in that, described voltage divider (22) is coil (N).
7. leakage protection circuit according to claim 6; it is characterized in that; described first loop (2) also comprises discharger (24); in parallel with described coil (N), for the moment in described coil (N) power-off, described coil (N) is discharged.
8. leakage protection circuit according to claim 7; it is characterized in that; described discharger (24) comprises the 6th diode (D5); one end that negative pole and the described coil (N) of described 6th diode (D5) are connected with the positive pole of described second controllable silicon (D6) couples, and one end that positive pole and the described coil (N) of described 6th diode (D5) are connected with the negative pole of described 5th diode (D7) couples.
9. leakage protection circuit according to claim 5, it is characterized in that, described ON-OFF control circuit (3) comprises comparator (U1), the 3rd resistance (R1), the 4th resistance (R2) and the second electric capacity (C1);
Described comparator (U1) comprises first input end, the second input and an output;
Described 4th resistance (R2) is in parallel with described second electric capacity (C1), described one end of 3rd resistance (R1) and the 3rd end of described bridge circuit couple, the other end of described 3rd resistance (R1) couples with described 4th resistance (R2) and a common port of described second electric capacity (C1) and the first input end of described comparator (U1) simultaneously, another common end grounding of described 4th resistance (R2) and described second electric capacity (C1), second input termination predeterminated voltage (V2) of described comparator (U1), the output of described comparator (U1) is the voltage output end of described ON-OFF control circuit (3), couple with the control pole of described second controllable silicon (D6),
When the electric current in described first loop (2) is more than or equal to preset value, the voltage at the first input end place of described comparator (U1) is more than or equal to the predeterminated voltage (V2) of the second input end of described comparator (U1), the output output low level of described comparator (U1); When the electric current in described first loop (2) is less than preset value, the voltage at the first input end place of described comparator (U1) is less than the predeterminated voltage (V2) of the second input end of described comparator (U1), and the output of described comparator (U1) exports high level.
10. leakage protection circuit according to claim 9, it is characterized in that, described ON-OFF control circuit (3) also comprises voltage provides electronic circuit (34), and described voltage provides electronic circuit (34) to comprise the first voltage-stabiliser tube (Z1), the second voltage-stabiliser tube (Z2) and the 7th resistance (R7);
Described 7th resistance (R7) is in parallel with described first voltage-stabiliser tube (Z1) after connecting with described second voltage-stabiliser tube (Z2), couple with the 4th end of described bridge circuit after the positive pole of described second voltage-stabiliser tube (Z2) is connected with the positive pole of described first voltage-stabiliser tube (Z1), couple with the positive pole of described first controllable silicon (D8) after described 7th resistance (R7) is connected with the negative pole of described first voltage-stabiliser tube (Z1), one end that described 7th resistance (R7) is connected with the negative pole of described first voltage-stabiliser tube (Z1) is used for providing direct voltage to described comparator (U1), the common port of described 7th resistance (R7) and described second voltage-stabiliser tube (Z2) is for exporting described predeterminated voltage (V2).
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| CN107919661A (en) * | 2017-12-28 | 2018-04-17 | 浙江多格电气有限公司 | A kind of modular Surge Protector |
| CN108270195A (en) * | 2017-02-17 | 2018-07-10 | 杰华特微电子（杭州）有限公司 | leakage protection circuit and method |
| CN110531219A (en) * | 2019-09-05 | 2019-12-03 | 上海芯荃微电子科技有限公司 | A kind of exchange detection method and circuit using switch drain |
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| CN104377647B (en) | 2018-02-27 |
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