CN204089154U - The overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking - Google Patents
The overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking Download PDFInfo
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- CN204089154U CN204089154U CN201420501867.0U CN201420501867U CN204089154U CN 204089154 U CN204089154 U CN 204089154U CN 201420501867 U CN201420501867 U CN 201420501867U CN 204089154 U CN204089154 U CN 204089154U
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Abstract
The utility model discloses the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking, it comprises ac current source input module, lightning-protection module, electromagnetic interface filter, overvoltage protective module, rectification module and filtration module, described overvoltage protective module comprises overvoltage protective module A and the overvoltage protective module B of two symmetrical configuration, by the interconnection of respective photoelectric coupling circuit between overvoltage protective module A and overvoltage protective module B, described overvoltage protective module A comprises rectification circuit, comparison circuit, amplifying circuit, reference voltage circuit, feedback control circuit, photoelectric coupling circuit and overvoltage protection switch.The utility model reduces power loss during ac current source overvoltage protection greatly, and over-voltage protection point temperature influence is very little, can reduce power supply unit volume, improves power supply unit reliability.When can also make ac current source overvoltage protection forward and negative sense protection magnitude of voltage close.
Description
Technical field
The utility model relates to overvoltage protection field, particularly relates to the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking.
Background technology
Intelligent grid is the developing direction of electrical network, and on-line monitoring is a part for intelligent grid.And the power pack of on-line monitoring system, be the basis that on-line monitoring system can normally run.By electromagnetic induction power taking on the ground wire of power transmission network, the powerup issue of on-line monitoring system effectively can be solved.As long as because ground wire has alternating current, just can obtain ac current source by iron core by electromagnetic induction principle, similar current transformer, power and the load resistance resistance of the AC power obtained are directly proportional, according to formula P=I
2* R, supposes current Iconst, then power P is proportional to resistance R.So when resistance R increases, power output increases, export piezoelectric voltage also to increase, when load there is no consumed power or open a way this extreme case time, the alternating current output voltage obtained can raise greatly, can exceed the withstand voltage limit of element device in circuit and damage components and parts.So the alternating current obtained must add overvoltage crowbar.
As shown in Figure 1, a kind of traditional typical ac current source overvoltage protection scheme, adopts bidirectional triode thyristor to realize ac current source overvoltage protection in this traditional scheme.
The operation principle of this traditional scheme is: direct-flow electricity utilization apparatus electricity consumption electric current reduces, and be equivalent to direct-flow electricity utilization apparatus internal resistance and increase, direct-flow electricity utilization apparatus both end voltage raises, and ac current source output voltage raises.Now, overvoltage crowbar operation principle divides the positive half cycle of ac current source and negative half period two kinds of situation analysis.
This traditional scheme overvoltage crowbar is in the positive half cycle operation principle of alternating current source:
Suppose that in Fig. 1, the relative B point voltage of A point voltage is just, i.e. V
aBfor positive voltage.The relative B point of C point is positive voltage, i.e. V
cBfor positive voltage.Work as V
cBprogressively raise, when reaching the conducting voltage of bidirectional diode DB1, bidirectional diode DB1 conducting, after electric current from left to right flows through bidirectional diode DB1, resistance R5, charges to electric capacity C2, and then the relative B point voltage of G point voltage is just, i.e. V
gBfor positive voltage, work as V
gBwhen reaching the positive conducting valve threshold voltage of bidirectional triode thyristor VT1, bidirectional triode thyristor VT1 conducting, electric current flow to MT1 from MT2, is equivalent to ac current source short circuit, ac current source is no longer powered to direct-flow electricity utilization apparatus, and is powered to direct-flow electricity utilization apparatus by the electric energy stored in electric capacity C3.Until alternating current source negative half period arrives, now V
aBwill be negative by rotating forward, the electric current flowing through bidirectional triode thyristor VT1 first reduces, and then to zero, more oppositely, bidirectional triode thyristor VT1, due to self-characteristic, can automatically shut down when current over-zero.
This traditional scheme overvoltage crowbar is in alternating current source negative half period operation principle:
Suppose that in Fig. 1, A point voltage relative B point voltage is negative, i.e. V
aBfor negative voltage.The relative B point of C point is negative voltage, i.e. V
cBfor negative voltage.Work as V
cBprogressively reduce, when reaching the conducting voltage of bidirectional diode DB1, bidirectional diode DB1 conducting, electric current flows through resistance R5 from right to left, and bidirectional diode DB1 is to C2 electric discharge (also can think reverse charging), and then G point voltage relative B point voltage is negative, i.e. V
gBfor negative voltage, work as V
gBwhen reaching the negative conducting valve threshold voltage of bidirectional triode thyristor VT1, bidirectional triode thyristor VT1 conducting, electric current flow to MT2 from MT1, is equivalent to ac current source short circuit, ac current source is no longer powered to direct-flow electricity utilization apparatus, and is powered to direct-flow electricity utilization apparatus by the electric energy stored in electric capacity C3.Until the positive half cycle of alternating current source arrives, now V
aBto turn negative number to positive number, the electric current flowing through bidirectional triode thyristor VT1 first reduces, and then to zero, more oppositely, bidirectional triode thyristor VT1, due to self-characteristic, can automatically shut down when current over-zero.
The disadvantage of prior art is: the VTM value of bidirectional triode thyristor is general all comparatively large, and VTM value is for after bidirectional triode thyristor is conducted through electric current, and the potential difference between MT2 pin and MT1 pin, when bidirectional triode thyristor is conducted through larger current, loss is quite large.Because the trigger voltage threshold values of bidirectional triode thyristor 1,3 quadrant is different, thus when causing ac current source overvoltage protection, forward and negative sense protect magnitude of voltage inconsistent.
Utility model content
The purpose of this utility model is to overcome the deficiencies in the prior art, provides the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking, the problem that when overcoming overvoltage protection, loss power is too large.
The purpose of this utility model is achieved through the following technical solutions: the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking, it comprises ac current source input module, lightning-protection module, electromagnetic interface filter, overvoltage protective module, rectification module and filtration module, ac current source input module is connected with lightning-protection module, lightning-protection module is connected with electromagnetic interface filter, electromagnetic interface filter is connected with overvoltage protective module, overvoltage protective module is connected with rectification module, rectification module is connected with filtration module, the input of lightning-protection module exports with ac current source and is connected, filtration module exports and is connected with direct-flow electricity utilization apparatus.
Described overvoltage protective module comprises overvoltage protective module A and the overvoltage protective module B of two symmetrical configuration, by the interconnection of respective photoelectric coupling circuit between overvoltage protective module A and overvoltage protective module B.
Described overvoltage protective module A comprises rectification circuit, comparison circuit, amplifying circuit, reference voltage circuit, feedback control circuit, photoelectric coupling circuit and overvoltage protection switch.
The alternating current of input is converted to direct current by described rectification circuit, one road direct current of rectification circuit export through voltage stabilizing circuit respectively with comparison circuit power end, the power end of amplifying circuit, and reference voltage circuit connects, another road direct current of rectification circuit exports and is connected with the in-phase input end of comparison circuit after dividing potential drop, the output of reference voltage circuit is connected with the inverting input of comparison circuit, the output of comparison circuit respectively with amplifying circuit, photoelectric coupling circuit connects, the output of amplifying circuit is connected with overvoltage protection switch, one end of feedback control circuit is connected with the output of comparison circuit, the other end of feedback control circuit is connected with the in-phase input end of comparison circuit, photoelectric coupling circuit is connected with the in-phase input end of the comparison circuit of overvoltage protective module B, conversely, the photoelectric coupling circuit of overvoltage protective module B is also connected with the in-phase input end of the comparison circuit of overvoltage protective module A.
Described rectification circuit is half-wave rectifying circuit, described half-wave rectifying circuit comprises rectifier diode D1 and commutation capacitor C5, the anode of described rectifier diode D1 is connected with ac input end B, the negative electrode of rectifier diode D1 is connected with the anode of commutation capacitor C5, the negative electrode of commutation capacitor C5 is connected with ac input end A, and the mid point of rectifier diode D1 and commutation capacitor C5 exports direct current.
Described voltage stabilizing circuit comprises resistance R7, voltage stabilizing triode Q1 and voltage stabilizing didoe Z1, the described collector electrode of voltage stabilizing triode Q1 exports with the direct current of rectification circuit and is connected, the emitter of voltage stabilizing triode Q1 is connected with the power end of comparison circuit, the base stage of voltage stabilizing triode Q1 is connected with the negative electrode of voltage stabilizing didoe Z1, the anode of voltage stabilizing didoe Z1 is connected with ac input end A, the emitter of voltage stabilizing triode Q1 is also connected with ac input end A, between the collector electrode that resistance R7 is connected in parallel on voltage stabilizing triode Q1 and base stage by electric capacity C7.
Described bleeder circuit comprises divider resistance R1 and divider resistance R3, described divider resistance R1 and divider resistance R3 is connected in series, one end of series connection exports with the direct current of rectification circuit and is connected, the other end is connected with ac input end A, the mid point of series connection is connected with the in-phase input end of comparison circuit, and the mid point of series connection is also connected with ac input end A by electric capacity C1.
Described comparison circuit comprises operational amplifier U1, and operational amplifier U1 earth terminal is connected with ac input end A.
Described amplifying circuit is push-pull amplifier circuit; described push-pull amplifier circuit comprises amplifying triode Q3 and amplifying triode Q5; the base stage of described amplifying triode Q3 is connected with the output of the base stage of amplifying triode Q5 and operational amplifier U1; the collector electrode of amplifying triode Q3 is connected with the emitter of voltage stabilizing triode Q1; the emitter of amplifying triode Q3 is connected with the emitter of amplifying triode Q5 and overvoltage protection switch, and the collector electrode of amplifying triode Q5 is connected with ac input end A.
Described reference voltage circuit comprises voltage-stabiliser tube U3, resistance R9 and electric capacity C2, described voltage-stabiliser tube U3 is controllable accurate source of stable pressure TL431, the anode of described voltage-stabiliser tube U3 is connected with ac input end A, the negative electrode of voltage-stabiliser tube U3 is connected with the emitter of voltage stabilizing triode Q1 by resistance R9, the negative electrode of voltage-stabiliser tube U3 is also connected with ac input end A by electric capacity C2, and the negative electrode of voltage-stabiliser tube U3 is also connected with the reference pole of voltage-stabiliser tube U3 and the reverse input end of operational amplifier U1.
Described feedback control circuit comprises diode D3 and resistance R13, and the anode of diode D3 is connected with the output of operational amplifier U1, and the negative electrode of diode D3 is connected with the input in the same way of operational amplifier U1 by resistance R13.
Described photoelectric coupling circuit comprises photoelectrical coupler U5, resistance R10 and resistance R15, described photoelectrical coupler U5 input negative electrode is connected with the output of operational amplifier U1, photoelectrical coupler U5 input anode is connected with ac input end A by resistance R10, photoelectrical coupler U5 output emitter is connected with the input in the same way of the operational amplifier U2 symmetrical with operational amplifier U1 by resistance R15, and photoelectrical coupler U5 output collector electrode is connected with the emitter of the voltage stabilizing triode Q2 symmetrical with voltage stabilizing triode Q1.
Described overvoltage protection switch comprises switch MOS pipe Q7, diode D5, divider resistance R17, divider resistance R4 and voltage stabilizing didoe Z3, the source electrode of described switch MOS pipe Q7 is connected with ac input end A, the drain electrode of switch MOS pipe Q7 is connected with the drain electrode of the symmetrical switch MOS pipe Q8 with switch MOS pipe Q7, the grid of switch MOS pipe Q7 is connected with the emitter of amplifying triode Q3 and the emitter of amplifying triode Q5 by divider resistance R17, the grid of switch MOS pipe Q7 is also connected with ac input end A with voltage stabilizing didoe Z3 by divider resistance R4 in parallel, the negative electrode of voltage stabilizing didoe Z3 is connected with the grid of switch MOS pipe Q7, the anode of diode D5 is connected with the source electrode of switch MOS pipe Q7, the negative electrode of diode D5 is connected with the drain electrode of switch MOS pipe Q7.
The beneficial effects of the utility model are: the utility model adopts two N-channel MOS FET to realize ac current source overvoltage protection; greatly can reduce power loss during ac current source overvoltage protection; over-voltage protection point temperature influence is very little; power supply unit volume can be reduced, improve power supply unit reliability.When can also make ac current source overvoltage protection forward and negative sense protection magnitude of voltage close.
Accompanying drawing explanation
Fig. 1 is traditional typical ac current source overvoltage protection resolution circuitry schematic diagram.
Fig. 2 is the utility model system block diagram;
Fig. 3 is the utility model overvoltage protection resolution circuitry schematic diagram;
The graph of a relation of electric current and voltage when Fig. 4 is bidirectional triode thyristor work;
Fig. 5 is the Realization of Simulation result figure of the utility model overvoltage protective system.
Embodiment
Below in conjunction with accompanying drawing, the technical solution of the utility model is described in further detail, but protection range of the present utility model is not limited to the following stated.
Intelligent grid is the developing direction of electrical network, and on-line monitoring is a part for intelligent grid.And the power pack of on-line monitoring system, be the basis that on-line monitoring system can normally run.By electromagnetic induction power taking on the ground wire of power transmission network, the powerup issue of on-line monitoring system effectively can be solved.As long as because ground wire has alternating current, just ac current source can be obtained by iron core by electromagnetic induction principle.Similar current transformer, power and the load resistance resistance of the AC power obtained are directly proportional, according to formula P=I
2* R, supposes current Iconst, then power P is proportional to resistance R.So when resistance R increases, power output increases, export piezoelectric voltage also to increase, when load there is no consumed power or open a way this extreme case time, the alternating current output voltage obtained can raise greatly, can exceed the withstand voltage limit of element device in circuit and damage components and parts.So the alternating current obtained must add overvoltage crowbar.
The utility model adopts two N-channel MOS FET to substitute bidirectional triode thyristor and realizes ac current source overvoltage protection, greatly can reduce power loss during ac current source overvoltage protection, can reduce power supply unit volume, improves power supply unit reliability.When can also make ac current source overvoltage protection forward and negative sense protection magnitude of voltage close.
As shown in Figure 2; the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking; it comprises ac current source input module, lightning-protection module, electromagnetic interface filter, overvoltage protective module, rectification module and filtration module; ac current source input module is connected with lightning-protection module; lightning-protection module is connected with electromagnetic interface filter; electromagnetic interface filter is connected with overvoltage protective module; overvoltage protective module is connected with rectification module; rectification module is connected with filtration module; the input of lightning-protection module exports with ac current source and is connected, and filtration module exports and is connected with direct-flow electricity utilization apparatus.
1, ac current source: flow through AC power on electric power transmission network ground wire, the principle utilizing magnet ring battery to respond to is from power taking ground wire, and similar operation of current transformers principle, the electricity obtained in the short time can be equivalent to ac current source.
2, lightning-protection module: by piezo-resistance, the lightning protection circuit that the components and parts such as gas discharge tube and inductance are designed, the energy of indirect lightning strike of releasing to a certain extent, prevents the energy of indirect lightning strike from damaging components and parts in circuit below.
3, electromagnetic interface filter: electromagnetic interface filter is Electromagnetic interference filter, it is the filter designed by X electric capacity, Y capacitance, common mode inductance and differential mode inductance, prevent extraneous common mode disturbances and differential mode interference from affecting the normal work of power consumption equipment below, also the differential mode simultaneously preventing power consumption equipment from producing and common mode disturbances are passed by wire, cause interference to other electronic equipments be connected by wire.
4, overvoltage protective module: be made up of the duplicate circuit of upper and lower two parts, the operation principle of upper and lower two parts circuit is just the same.
5, rectification module: by rectifier bridge or four diodes, be DC power supply AC power rectification.
6, filtration module: by Large Copacity alminium electrolytic condenser, or CLC filter circuit realizes filtering, to obtain more desirable direct current.
7, direct-flow electricity utilization apparatus: can be the cell board realizing certain function also can be video camera, sensor power consumption equipment.
As shown in Figure 3, described overvoltage protective module comprises overvoltage protective module A and the overvoltage protective module B of two symmetrical configuration, by the interconnection of respective photoelectric coupling circuit between overvoltage protective module A and overvoltage protective module B.
Described overvoltage protective module A comprises rectification circuit, comparison circuit, amplifying circuit, reference voltage circuit, feedback control circuit, photoelectric coupling circuit and overvoltage protection switch.
The alternating current of input is converted to direct current by described rectification circuit, one road direct current of rectification circuit export through voltage stabilizing circuit respectively with comparison circuit power end, the power end of amplifying circuit, and reference voltage circuit connects, another road direct current of rectification circuit exports and is connected with the in-phase input end of comparison circuit after dividing potential drop, the output of reference voltage circuit is connected with the inverting input of comparison circuit, the output of comparison circuit respectively with amplifying circuit, photoelectric coupling circuit connects, the output of amplifying circuit is connected with overvoltage protection switch, one end of feedback control circuit is connected with the output of comparison circuit, the other end of feedback control circuit is connected with the in-phase input end of comparison circuit, photoelectric coupling circuit is connected with the in-phase input end of the comparison circuit of overvoltage protective module B, conversely, the photoelectric coupling circuit of overvoltage protective module B is also connected with the in-phase input end of the comparison circuit of overvoltage protective module A.
Described rectification circuit is half-wave rectifying circuit, described half-wave rectifying circuit comprises rectifier diode D1 and commutation capacitor C5, the anode of described rectifier diode D1 is connected with ac input end B, the negative electrode of rectifier diode D1 is connected with the anode of commutation capacitor C5, the negative electrode of commutation capacitor C5 is connected with ac input end A, and the mid point of rectifier diode D1 and commutation capacitor C5 exports direct current.
Described voltage stabilizing circuit comprises resistance R7, voltage stabilizing triode Q1 and voltage stabilizing didoe Z1, the described collector electrode of voltage stabilizing triode Q1 exports with the direct current of rectification circuit and is connected, the emitter of voltage stabilizing triode Q1 is connected with the power end of comparison circuit, the base stage of voltage stabilizing triode Q1 is connected with the negative electrode of voltage stabilizing didoe Z1, the anode of voltage stabilizing didoe Z1 is connected with ac input end A, the emitter of voltage stabilizing triode Q1 is also connected with ac input end A, between the collector electrode that resistance R7 is connected in parallel on voltage stabilizing triode Q1 and base stage by electric capacity C7.
Described bleeder circuit comprises divider resistance R1 and divider resistance R3, described divider resistance R1 and divider resistance R3 is connected in series, one end of series connection exports with the direct current of rectification circuit and is connected, the other end is connected with ac input end A, the mid point of series connection is connected with the in-phase input end of comparison circuit, and the mid point of series connection is also connected with ac input end A by electric capacity C1.
Described comparison circuit comprises operational amplifier U1, and operational amplifier U1 earth terminal is connected with ac input end A.
Described amplifying circuit is push-pull amplifier circuit; described push-pull amplifier circuit comprises amplifying triode Q3 and amplifying triode Q5; the base stage of described amplifying triode Q3 is connected with the output of the base stage of amplifying triode Q5 and operational amplifier U1; the collector electrode of amplifying triode Q3 is connected with the emitter of voltage stabilizing triode Q1; the emitter of amplifying triode Q3 is connected with the emitter of amplifying triode Q5 and overvoltage protection switch, and the collector electrode of amplifying triode Q5 is connected with ac input end A.
Described reference voltage circuit comprises voltage-stabiliser tube U3, resistance R9 and electric capacity C2, described voltage-stabiliser tube U3 is controllable accurate source of stable pressure TL431, the anode of described voltage-stabiliser tube U3 is connected with ac input end A, the negative electrode of voltage-stabiliser tube U3 is connected with the emitter of voltage stabilizing triode Q1 by resistance R9, the negative electrode of voltage-stabiliser tube U3 is also connected with ac input end A by electric capacity C2, and the negative electrode of voltage-stabiliser tube U3 is also connected with the reference pole of voltage-stabiliser tube U3 and the reverse input end of operational amplifier U1.
Described feedback control circuit comprises diode D3 and resistance R13, and the anode of diode D3 is connected with the output of operational amplifier U1, and the negative electrode of diode D3 is connected with the input in the same way of operational amplifier U1 by resistance R13.
Described photoelectric coupling circuit comprises photoelectrical coupler U5, resistance R10 and resistance R15, described photoelectrical coupler U5 input negative electrode is connected with the output of operational amplifier U1, photoelectrical coupler U5 input anode is connected with ac input end A by resistance R10, photoelectrical coupler U5 output emitter is connected with the input in the same way of the operational amplifier U2 symmetrical with operational amplifier U1 by resistance R15, and photoelectrical coupler U5 output collector electrode is connected with the emitter of the voltage stabilizing triode Q2 symmetrical with voltage stabilizing triode Q1.
Described overvoltage protection switch comprises switch MOS pipe Q7, diode D5, divider resistance R17, divider resistance R4 and voltage stabilizing didoe Z3, the source electrode of described switch MOS pipe Q7 is connected with ac input end A, the drain electrode of switch MOS pipe Q7 is connected with the drain electrode of the symmetrical switch MOS pipe Q8 with switch MOS pipe Q7, the grid of switch MOS pipe Q7 is connected with the emitter of amplifying triode Q3 and the emitter of amplifying triode Q5 by divider resistance R17, the grid of switch MOS pipe Q7 is also connected with ac input end A with voltage stabilizing didoe Z3 by divider resistance R4 in parallel, the negative electrode of voltage stabilizing didoe Z3 is connected with the grid of switch MOS pipe Q7, the anode of diode D5 is connected with the source electrode of switch MOS pipe Q7, the negative electrode of diode D5 is connected with the drain electrode of switch MOS pipe Q7.
Wherein, voltage stabilizing triode Q1, Q2 and amplifying triode Q3, Q4 are NPN triode, and amplifying triode Q5, Q6 are PNP triode, and switch MOS pipe Q7, Q8 are NMOS tube.
Overvoltage protective module in the utility model comprises overvoltage protective module A and the overvoltage protective module B of two symmetrical configuration; its components and parts composition is identical with circuit structure; namely the utility model overvoltage protective module is made up of the duplicate circuit of upper and lower two parts, and the operation principle of upper and lower two parts circuit is also just the same.
Operation principle below with regard to overvoltage protective module lower part circuit is described, and is namely described the operation principle of overvoltage protective module B, according to the operation principle of the known overvoltage protective module A of the operation principle of overvoltage protective module B.
When ac input end A is relative and ac input end B is timing.
Rectifier diode D1 not conducting, rectifier diode D2 conducting, electric current charges to commutation capacitor C6, the voltage at commutation capacitor C6 two ends, by divider resistance R2 and divider resistance R5 dividing potential drop, the mid point of divider resistance R2 and divider resistance R5 is the input voltage of operational amplifier U2 input in the same way, and this input voltage is designated as branch pressure voltage Vins.
The positive pole of commutation capacitor C6, the voltage stabilizing circuit formed through resistance R8, voltage stabilizing didoe Z2 and NPN voltage stabilizing triode Q2 is again powered to operational amplifier U2, be connected to the 8th pin operating voltage input VCC of operational amplifier U2, VCC voltage is determined by the magnitude of voltage of voltage stabilizing didoe Z2.
VCC voltage flows through electric current to voltage-stabiliser tube U4 through resistance R11, voltage-stabiliser tube U4 is TL431, the reference pole R of voltage-stabiliser tube U4 and negative electrode K pole short circuit, the effect of such voltage-stabiliser tube U4 is exactly a high accuracy 2.5V voltage-stabiliser tube with temperature compensation function, provides 2.5V reference voltage to hold to the 2nd pin anti-phase input A-of operational amplifier U2.
The 3rd pin that the 1st pin output terminals A out of operational amplifier U2 is connected to operational amplifier U2 by diode D4 and resistance R16 inputs A+ end in the same way, realizes positive feedback and controls.
Simultaneously the 1st pin output terminals A out of operational amplifier U2 recommends amplification by triode Q4 and triode Q6, and carry out driving switch MOS and close Q8, it is N-channel MOS FET that switch MOS closes Q8.
In addition, the input of operational amplifier U2 the 1st pin output terminals A out series connection photoelectrical coupler U6, through resistance R12 to ac input end B electronegative potential, like this, once the 1st pin output terminals A out of operational amplifier U2 exports high level, so the input of photoelectrical coupler U6 flows through electric current, the output conducting of photoelectrical coupler U6, electric current is from operational amplifier U1 the 8th pin operating voltage input VCC, flow through the output of photoelectrical coupler U6, and the 3rd pin homophase input A+ end of operational amplifier U1 is flow to by resistance R14, thus improve operational amplifier U1 the 3rd pin homophase input A+ terminal voltage.
The operating state of overvoltage protective module circuit has two kinds:
(1) normal operating conditions
When branch pressure voltage Vins is less than 2.5V reference voltage; the input terminal voltage in the same way of operational amplifier U2 is less than reverse input end voltage; the 1st pin output terminals A out of operational amplifier U2 exports as low level; diode D4, amplifying triode Q4, photoelectrical coupler U6 are in off state; amplifying triode Q6 conducting; the grid voltage of switch MOS pipe Q8 is pulled low to close to source voltage; so switch MOS pipe Q8 turns off; now whole overvoltage crowbar is open-circuit condition relative to ac input end A and ac input end B, and this is state when not producing protection.
Now; in overvoltage crowbar, the branch pressure voltage Vins of divider resistance R2 and divider resistance R5 inputs as the homophase of operational amplifier U2; because divider resistance R2, resistance R15 and resistance R16 are in parallel; so the resistance of R2//R15//R16 must be less than R2; so the voltage of divider resistance R2 can rise; this is exactly the effect of positive feedback; ensure that the 1st pin of operational amplifier U2 exports high level and can continue for some time; prevent switch MOS pipe Q7 and switch MOS pipe Q8 from just having opened and having turned off immediately, improve the stability of system.
(2) overvoltage protection state
When branch pressure voltage Vins is greater than 2.5V reference voltage, the input terminal voltage in the same way of operational amplifier U2 is greater than reverse input end voltage, so the 1st pin output terminals A out of operational amplifier U2 exports as high level, diode D4, amplifying triode Q4, photoelectrical coupler U6 are in conducting state, amplifying triode Q6 closes, the grid voltage of switch MOS pipe Q8 is increased to the VCC voltage close to operational amplifier U2 instantaneously, so switch MOS pipe Q8 transient switching.
Meanwhile, due to the conducting of photoelectrical coupler U6 input, the VCC voltage positive feedback of operational amplifier U1 is passed to the 3rd pin in-phase input end of operational amplifier U1 by photoelectrical coupler U6 output.
In like manner, switch MOS pipe Q7 transient switching.After switch MOS pipe Q7 and switch MOS pipe Q8 conducting simultaneously, the switch MOS pipe Q7 that ac input end A and ac input end B is switched on and switch MOS pipe Q8 short circuit, realize over-voltage protecting function.
After switch MOS pipe Q7 and switch MOS pipe Q8 conducting, the voltage at commutation capacitor C6 two ends is rectified diode D2 clamper, keep certain voltage, because the electric energy of overvoltage crowbar need of work is provided by commutation capacitor C6, so the voltage at the positive and negative two ends of commutation capacitor C6 can linearly decline, the voltage always dropping to operational amplifier U2 the 3rd pin input is in the same way less than 2.5V reference voltage, now, the 1st pin output low level of operational amplifier U2, due to positive feedback, the voltage of operational amplifier U2 the 3rd pin input in the same way can be dragged down certain voltage instantaneously, prevent switch MOS pipe Q7 and switch MOS pipe Q8 from just having turned off and open-minded immediately.
It is to be noted: from operational amplifier U2 the 1st pin export high level by positive feedback make operational amplifier U2 the 3rd pin in the same way input terminal voltage be increased beyond the moment of 2.5V reference level, to operational amplifier U2 the 3rd pin in the same way input terminal voltage linearly drop to and be less than the 2.5V reference level moment, during this period of time, 1st pin of operational amplifier U2 exports high level always, makes switch MOS pipe Q7 and switch MOS pipe Q8 be in conducting state during this period of time always.
If switch MOS pipe Q7 and switch MOS pipe Q8 has just opened and has turned off immediately, or, switch MOS pipe Q7 and switch MOS pipe Q8 has just turned off and open-minded immediately, system is caused to enter unstable operating state, may cause switch MOS pipe Q7 and switch MOS pipe Q8 because of the reason loss of instability excessive, junction temperature is too high and damage.
Due to symmetrical on overvoltage protective module A and overvoltage protective module B structure, its components and parts composition is identical with circuit structure, and the operation principle when ac input end A is negative relative to interchange input B and above-mentioned analysis are in like manner.
Illustrate according to concrete instance below, the problem that when the utility model scheme effectively overcomes overvoltage protection, loss power is too large.
As shown in Figure 1, when doing overvoltage protection with bidirectional triode thyristor, suppose that bidirectional triode thyristor adopts this model of HQ6025RH5, from its databook, obtain the graph of a relation of electric current and voltage when bidirectional triode thyristor works, be illustrated in fig. 4 shown below.
Be illustrated in fig. 4 shown below, when this bidirectional triode thyristor flows through 10A electric current, the voltage drop representative value of MT1 and MT2 pin is about 1.025V, and now the loss power of bidirectional triode thyristor is according to formula P=I*V, and the loss power that can calculate bidirectional triode thyristor is 10.25W.
In the utility model scheme, suppose that switch MOS pipe Q7 and switch MOS pipe Q8 adopts this MOSFET of IPP045N10N3G, according to its databook, its conducting resistance representative value is 4.2m Ω.So, after switch MOS pipe Q7 tandem tap metal-oxide-semiconductor Q8 conducting, the resistance between switch MOS pipe Q7 source electrode and switch MOS pipe Q8 source electrode is 8.4m Ω.
If the electric current flow through after short circuit is similarly 10A when adopting bidirectional triode thyristor, the total losses so on switch MOS pipe Q7 and switch MOS pipe Q8 are: P=10*10*8.4=840(mW), namely total losses power is 0.84W.
And adopt the loss of bidirectional triode thyristor to be 10.25W, visible, the loss of bidirectional triode thyristor scheme is about 12 times of the utility model scheme.
As shown in Figure 5, carry out emulation experiment to the utility model overvoltage protective system, in experiment, inputting a road peak value is the alternating current of 96V, and arranging overvoltage protection value is 45V, judges whether this system effectively can carry out protective separation.From simulation result figure, peak value is after the alternating current of 96V inputs the utility model overvoltage protective system, only export-46.8V ~ 46.0V low pressure stage, and high pressure section is all isolated effectively, thus reaches the object of overvoltage protection.
From Fig. 5 also; when overvoltage protective system is from overvoltage protection state to normal operating conditions; overvoltage protective system does not enter normal operating conditions at once; but sustained overvoltage guard mode, after a period of time, then enter normal operating conditions; this meets design of the present utility model completely; do not allow switch MOS pipe just to turn off conducting again, prevent switch MOS pipe because of the reason loss of instability excessive, cause junction temperature too high and damage.
Emulate known by experiment, the utility model overvoltage protective system has feasibility and validity.
The utility model adopts two N-channel MOS FET to substitute bidirectional triode thyristor and realizes ac current source overvoltage protection; conducting or simultaneously turn off while adopting operational amplifier and photoelectrical coupler to realize two N-channel MOS FET, adopts amplifier positive feedback and power supply capacitor discharge to control the ON time of two N-channel MOS FET.
The utility model adopts two N-channel MOS FET, greatly can reduce power loss during ac current source overvoltage protection, can reduce power supply unit volume, improves power supply unit reliability.When can also make ac current source overvoltage protection forward and negative sense protection magnitude of voltage close.
Over-voltage protection point temperature influence of the present utility model is very little, because the voltage-stabiliser tube U3 and the voltage-stabiliser tube U4 that produce 2.5V reference data voltage are TL431, have temperature compensation function, when high/low temperature differs greatly, can provide stable reference voltage.
The utility model, when overvoltage protection, can make power device fast conducting and shutoff, reduces switching loss, improves the reliability of power device.
Claims (10)
1. the overvoltage crowbar of ultra-high-tension power transmission line ground wire power taking; it comprises ac current source input module, lightning-protection module, electromagnetic interface filter, overvoltage protective module, rectification module and filtration module; ac current source input module is connected with lightning-protection module; lightning-protection module is connected with electromagnetic interface filter; electromagnetic interface filter is connected with overvoltage protective module; overvoltage protective module is connected with rectification module; rectification module is connected with filtration module; the input of lightning-protection module exports with ac current source and is connected; filtration module exports and is connected with direct-flow electricity utilization apparatus, it is characterized in that:
Described overvoltage protective module comprises overvoltage protective module A and the overvoltage protective module B of two symmetrical configuration, by the interconnection of respective photoelectric coupling circuit between overvoltage protective module A and overvoltage protective module B;
Described overvoltage protective module A comprises rectification circuit, comparison circuit, amplifying circuit, reference voltage circuit, feedback control circuit, photoelectric coupling circuit and overvoltage protection switch;
The alternating current of input is converted to direct current by described rectification circuit, one road direct current of rectification circuit export through voltage stabilizing circuit respectively with comparison circuit power end, the power end of amplifying circuit, and reference voltage circuit connects, another road direct current of rectification circuit exports and is connected with the in-phase input end of comparison circuit after dividing potential drop, the output of reference voltage circuit is connected with the inverting input of comparison circuit, the output of comparison circuit respectively with amplifying circuit, photoelectric coupling circuit connects, the output of amplifying circuit is connected with overvoltage protection switch, one end of feedback control circuit is connected with the output of comparison circuit, the other end of feedback control circuit is connected with the in-phase input end of comparison circuit, photoelectric coupling circuit is connected with the in-phase input end of the comparison circuit of overvoltage protective module B, conversely, the photoelectric coupling circuit of overvoltage protective module B is also connected with the in-phase input end of the comparison circuit of overvoltage protective module A.
2. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking; it is characterized in that: described rectification circuit is half-wave rectifying circuit; described half-wave rectifying circuit comprises rectifier diode D1 and commutation capacitor C5; the anode of described rectifier diode D1 is connected with ac input end B; the negative electrode of rectifier diode D1 is connected with the anode of commutation capacitor C5; the negative electrode of commutation capacitor C5 is connected with ac input end A, and the mid point of rectifier diode D1 and commutation capacitor C5 exports direct current.
3. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking, it is characterized in that: described voltage stabilizing circuit comprises resistance R7, voltage stabilizing triode Q1 and voltage stabilizing didoe Z1, the described collector electrode of voltage stabilizing triode Q1 exports with the direct current of rectification circuit and is connected, the emitter of voltage stabilizing triode Q1 is connected with the power end of comparison circuit, the base stage of voltage stabilizing triode Q1 is connected with the negative electrode of voltage stabilizing didoe Z1, the anode of voltage stabilizing didoe Z1 is connected with ac input end A, the emitter of voltage stabilizing triode Q1 is also connected with ac input end A by electric capacity C7, between the collector electrode that resistance R7 is connected in parallel on voltage stabilizing triode Q1 and base stage.
4. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking; it is characterized in that: described bleeder circuit comprises divider resistance R1 and divider resistance R3; described divider resistance R1 and divider resistance R3 is connected in series; one end of series connection exports with the direct current of rectification circuit and is connected; the other end is connected with ac input end A; the mid point of series connection is connected with the in-phase input end of comparison circuit, and the mid point of series connection is also connected with ac input end A by electric capacity C1.
5. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking, is characterized in that: described comparison circuit comprises operational amplifier U1, operational amplifier U1 earth terminal is connected with ac input end A.
6. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking, it is characterized in that: described amplifying circuit is push-pull amplifier circuit, described push-pull amplifier circuit comprises amplifying triode Q3 and amplifying triode Q5, the base stage of described amplifying triode Q3 is connected with the output of the base stage of amplifying triode Q5 and operational amplifier U1, the collector electrode of amplifying triode Q3 is connected with the emitter of voltage stabilizing triode Q1, the emitter of amplifying triode Q3 is connected with the emitter of amplifying triode Q5 and overvoltage protection switch, the collector electrode of amplifying triode Q5 is connected with ac input end A.
7. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking, it is characterized in that: described reference voltage circuit comprises voltage-stabiliser tube U3, resistance R9 and electric capacity C2, described voltage-stabiliser tube U3 is controllable accurate source of stable pressure TL431, the anode of described voltage-stabiliser tube U3 is connected with ac input end A, the negative electrode of voltage-stabiliser tube U3 is connected with the emitter of voltage stabilizing triode Q1 by resistance R9, the negative electrode of voltage-stabiliser tube U3 is also connected with ac input end A by electric capacity C2, the negative electrode of voltage-stabiliser tube U3 is also connected with the reference pole of voltage-stabiliser tube U3 and the reverse input end of operational amplifier U1.
8. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking; it is characterized in that: described feedback control circuit comprises diode D3 and resistance R13; the anode of diode D3 is connected with the output of operational amplifier U1, and the negative electrode of diode D3 is connected with the input in the same way of operational amplifier U1 by resistance R13.
9. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking, it is characterized in that: described photoelectric coupling circuit comprises photoelectrical coupler U5, resistance R10 and resistance R15, described photoelectrical coupler U5 input negative electrode is connected with the output of operational amplifier U1, photoelectrical coupler U5 input anode is connected with ac input end A by resistance R10, photoelectrical coupler U5 output emitter is connected with the input in the same way of the operational amplifier U2 symmetrical with operational amplifier U1 by resistance R15, photoelectrical coupler U5 output collector electrode is connected with the emitter of the voltage stabilizing triode Q2 symmetrical with voltage stabilizing triode Q1.
10. the overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire according to claim 1 power taking, it is characterized in that: described overvoltage protection switch comprises switch MOS pipe Q7, diode D5, divider resistance R17, divider resistance R4 and voltage stabilizing didoe Z3, the source electrode of described switch MOS pipe Q7 is connected with ac input end A, the drain electrode of switch MOS pipe Q7 is connected with the drain electrode of the symmetrical switch MOS pipe Q8 with switch MOS pipe Q7, the grid of switch MOS pipe Q7 is connected with the emitter of amplifying triode Q3 and the emitter of amplifying triode Q5 by divider resistance R17, the grid of switch MOS pipe Q7 is also connected with ac input end A with voltage stabilizing didoe Z3 by divider resistance R4 in parallel, the negative electrode of voltage stabilizing didoe Z3 is connected with the grid of switch MOS pipe Q7, the anode of diode D5 is connected with the source electrode of switch MOS pipe Q7, the negative electrode of diode D5 is connected with the drain electrode of switch MOS pipe Q7.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420501867.0U CN204089154U (en) | 2014-09-02 | 2014-09-02 | The overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking |
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| CN201420501867.0U CN204089154U (en) | 2014-09-02 | 2014-09-02 | The overvoltage crowbar of a kind of ultra-high-tension power transmission line ground wire power taking |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104184111A (en) * | 2014-09-02 | 2014-12-03 | 四川汇源光通信有限公司 | Overvoltage protection circuit for high-voltage transmission line ground wire power getting |
| CN109245573A (en) * | 2018-11-13 | 2019-01-18 | 浙江奥科半导体有限公司 | Super-pressure combines silicon-controlled integration module without inductance voltage stabilizing chip |
-
2014
- 2014-09-02 CN CN201420501867.0U patent/CN204089154U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104184111A (en) * | 2014-09-02 | 2014-12-03 | 四川汇源光通信有限公司 | Overvoltage protection circuit for high-voltage transmission line ground wire power getting |
| CN104184111B (en) * | 2014-09-02 | 2017-02-15 | 四川汇源光通信有限公司 | Overvoltage protection circuit for high-voltage transmission line ground wire power getting |
| CN109245573A (en) * | 2018-11-13 | 2019-01-18 | 浙江奥科半导体有限公司 | Super-pressure combines silicon-controlled integration module without inductance voltage stabilizing chip |
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