CN202710671U - Open phase detecting circuit of three-phase power supply - Google Patents

Abstract

The utility model discloses an open phase detecting circuit of a three-phase power supply, which comprises three voltage division circuits correspondingly connected with three phases and three rectifier circuits connected with each voltage division circuit, wherein the three rectifier circuits are connected with a triode detecting circuit for detecting open phase signals, and each voltage division circuit comprises capacitors. The three-phase detecting circuit at the input side of the open phase detecting circuit selects the capacitors for voltage division and as the capacitors generate little heat at work, stability of the system is enhanced. The scheme of the utility model is simple, easy to realize and low in cost.

Description

The lack detection circuit of three-phase supply

Technical field

The utility model relates to a kind of power sense circuit, particularly a kind of lack detection circuit of three-phase supply.

Background technology

Phase three-wire three exchanges the input service mode and is widely used in the fields such as power supply, agricultural, Industry Control.In some application scenarios, such as power cell, if lack a phase, two of working current is met and is caused the rectifier bridge electric current to increase; If tested three-phase extracts from the phase-shifting transformer side, if lack a phase, can cause equally the biphase current of work excessive, thereby so that heating is serious, further cause burning rectifier bridge or phase-shifting transformer.On the other hand, phase shortage also can cause harmonic wave in the system to increase and the ripple current of DC support electric capacity increases.

Existing lack detection circuit often adopts mutual inductor step-down or isolation, three-phase commutation bridge rectification, filtering voltage regulation, detects or detect with modes such as electric resistance partial pressures with triode.

The electromagnetic radiation that the divider resistance that adopts in the existing phase shortage detection technique scheme produces when easily producing the work of higher heat and mutual inductor at work is so that Systems balanth is not high.

The utility model content

In view of this, the utility model is to provide a kind of lack detection circuit of three-phase supply, to solve the not high problem of said system stability.

For addressing the above problem, the utility model provides a kind of lack detection circuit of three-phase supply, comprise: corresponding three bleeder circuits that connect three-phase, each described bleeder circuit connects a rectification circuit separately, and three described rectification circuits connect the triode testing circuit that detects default phase signal; Each described bleeder circuit is made of electric capacity.

Preferably, the described electric capacity quantity of each described bleeder circuit is a plurality of, is connected in series.

Preferably, described rectification circuit is comprised of two diodes.

Preferably, each described rectification circuit also connects separately filter capacitor and voltage stabilizing diode.

Preferably, also comprise three photoelectrical couplers;

Each described rectification circuit is connected one of them photoelectrical coupler by filter capacitor separately with voltage stabilizing diode;

The output terminal of three described photoelectrical couplers connects described triode testing circuit.

Preferably, described triode testing circuit comprises:

NPN type triode, detection terminal;

The base stage of described NPN type triode connects the output terminal of described three described photoelectrical couplers; The collector of described NPN type triode connects noble potential and described detection terminal; The emitter of described NPN type triode connects earth terminal.

The beneficial effect of the utility model scheme shows:

1, this lack detection circuit three-phase input side is selected electric capacity, rather than electric resistance partial pressure or mutual inductor, has avoided selecting the heating of electric resistance partial pressure generation and the electromagnetic radiation that mutual inductor produces, and has increased the reliability of system.

2, the choosing of this lack detection circuit all is resistance, electric capacity, diode, optocoupler, the triode of commonly using.Small volume, cheap.

3, this lack detection circuit will select optocoupler that high-tension circuit and control circuit are kept apart, than selecting mutual inductor more to save volume.

4, the default phase signal of this lack detection circuit after optocoupler is comprehensive increases one-level with triode and drives and use capacitance-resistance filter, strengthened the antijamming capability of default phase signal and reliability, the stability of detection.

Description of drawings

Fig. 1 is the circuit diagram of this enforcement lack detection circuit;

Embodiment

For clearly demonstrating the technical scheme in the utility model, the below provides preferred embodiment and is described with reference to the accompanying drawings.

Referring to Fig. 1, lack detection circuit comprises that input terminal, A detect mutually, B detects mutually, C detects mutually, the signal synthesis module.

Be specially: input terminal J1 is A, B, C three-phase power input end.7 pin that 4 pin that 1 pin of J1 meets A phase power supply, J1 meet B phase power supply, J1 connect C phase power supply, and wherein 2,3,5,6 pin are for reserving pin, use with isolate withstand voltage.In practice, can select suitable terminal pins according to electric pressure.

The A phase detecting circuit is comprised of C1, C2, C3, D1, D2, D3, R1, U1.1 pin of the termination J1 of C1 is the input of A phase power supply; Another termination C2 of C1; The positive pole of another termination D1 of C2 and the negative pole of D3; The positive pole of C3 connects the negative pole of D1, the negative pole of D2, the end of R1; The negative pole of C3 connects the positive pole of D3, the positive pole of D2, the negative pole of U1 input; The positive pole of another termination U1 input of R1.Safety capacitor C 1, C2 are composed in series the alternating current path of A phase power supply, can increase according to the requirement of supply voltage height the number of capacitances in series.What cause flow through is the leakage current of electric capacity, so electric current is very little, thereby avoids adopting the electric resistance partial pressure step-down, especially during high voltage, the persistent fever of divider resistance itself easily damages, further, environment temperature also can be along with rising, thereby causes the stability of other device serviceabilitys in the system.D1, D3 are the rectification diode, and AC rectification is become direct current; C3 is filter capacitor, and the filtering burr keeps the steady of voltage; D2 is voltage stabilizing diode, and the voltage stabilization after the rectification on the numerical value of needs, is caused damage to device when avoiding overtension; R1 is current-limiting resistance, and the voltage after the rectification is input to the input end of optocoupler U1 after the R1 current limliting, guarantees that the electric current on the former limit of optocoupler is no more than its ratings; U1 is optocoupler, with high-tension circuit and control circuit isolation, and when A phase power supply is normal, the optocoupler conducting; When phase shortage or voltage are very low, not conducting of optocoupler.

The B phase detecting circuit is comprised of C4, C5, C6, D4, D5, D6, R2, U2.4 pin of the termination J1 of C4 are the input of B phase power supply; Another termination C5 of C4; The positive pole of another termination D4 of C5 and the negative pole of D6; The positive pole of C6 connects the negative pole of D4, the negative pole of D5, the end of R2; The negative pole of C6 connects the positive pole of D6, the positive pole of D5, the negative pole of U2 input; The positive pole of another termination U2 input of R2.Safety capacitor C 4, C5 are composed in series the alternating current path of B phase power supply, can increase according to the requirement of supply voltage height the number of capacitances in series.What cause flow through is the leakage current of electric capacity, so electric current is very little, thereby avoids adopting the electric resistance partial pressure step-down, especially during high voltage, the persistent fever of divider resistance itself easily damages, further, environment temperature also can be along with rising, thereby causes the stability of other device serviceabilitys in the system.D4, D6 become direct current for the arrangement diode with AC rectification; The C6 filter capacitor, the filtering burr keeps the steady of voltage; D5 is voltage stabilizing diode, on the numerical value of needs, avoids overtension that device is caused damage the voltage stabilization after the rectification; R2 is current-limiting resistance, and the voltage after the rectification is input to the input end of optocoupler U2 after the R2 current limliting, guarantees that the electric current on the former limit of optocoupler is no more than its ratings; U2 is optocoupler, with high-tension circuit and control circuit isolation, and when B phase power supply is normal, the optocoupler conducting; When phase shortage or voltage are very low, not conducting of optocoupler.

The C phase detecting circuit is comprised of C7, C8, C9, D7, D8, D9, R3, U3, and 7 pin of the termination J1 of C7 are the input of C phase power supply, another termination C8 of C7; The positive pole of another termination D7 of C8 and the negative pole of D9; The positive pole of C9 connects the negative pole of D7, the negative pole of D8, the end of R3; The negative pole of C9 connects the positive pole of D9, the positive pole of D8, the negative pole of U3 input; The positive pole of another termination U3 input of R3.Safety capacitor C 7, C8 are composed in series the alternating current path of C phase power supply, can increase according to the requirement of supply voltage height the number of capacitances in series.What cause flow through is the leakage current of electric capacity, so electric current is very little, thereby avoids adopting the electric resistance partial pressure step-down, especially during high voltage, the persistent fever of divider resistance itself easily damages, further, environment temperature also can be along with rising, thereby causes the stability of other device serviceabilitys in the system.D7, D9 become direct current for the arrangement diode with AC rectification; The C9 filter capacitor, the filtering burr keeps the steady of voltage; D8 is voltage stabilizing diode, on the numerical value of needs, avoids overtension that device is caused damage the voltage stabilization after the rectification; R3 is current-limiting resistance, and the voltage after the rectification is input to the input end of optocoupler U3 after the R3 current limliting, guarantees that the electric current on the former limit of optocoupler is no more than its ratings; U3 is optocoupler, with high-tension circuit and control circuit isolation, and when C phase power supply is normal, the optocoupler conducting; When phase shortage or voltage are very low, not conducting of optocoupler.

Signal integrated circuit is comprised of U1, U2, U3.The input cathode of U1, U2, U3 is shorted together.The output terminal of U1, U2, U3 is connected in series.Termination control power supply+5V of U1, another termination U2; Another termination U3 of U2; Another termination R6 of U3 is as the output behind the signal synthesis.The output terminal of U1, U2, three optocouplers of U3 is connected in series.When three-phase voltage was all normal, three all conductings of optocoupler were high level behind the signal synthesis; As long as when having a phase power phase shortage or voltage very low, the not conducting of optocoupler that it is corresponding is output as default low level behind the signal synthesis.

Driving circuit and lead-out terminal are comprised of R4, R5, R6, R7, C10, C11, Q1.The termination signal integrated circuit of R6, the base stage of another termination C11, R7 and Q1; C11 and R7 are in parallel, another termination DGND; The emitter of Q1 meets DGND; The collector of Q1 connects the end of R4, R5; Another termination 5V of R4; Another termination C10, the J2 of R5; Another termination DGND of C10; J2 is lead-out terminal, and its 1 pin and 2 pin short circuits get up to use.When phase shortage or voltage are very low, be the drop-down low level of R7 behind the signal synthesis, under low level effect, arrive lead-out terminal J2 behind the capacitance-resistance filter that not conducting of Q1, the output of collector form high level signal by R5, C10 after drawing on the R4.When phase shortage not, the high level behind the signal synthesis is through R6 current limliting, C11 filtering rear drive triode Q1 conducting, arrives lead-out terminal J2 behind the capacitance-resistance filter that the low level of collector output forms by R5, C10.

When the output level that detects detection terminal J2 is high level, can judge open phases of three-phase power source; When output level is low level, can judge not phase shortage.

Open phases of three-phase power source testing circuit of the present utility model by adopting electric capacity to carry out dividing potential drop at three-phase detection circuit input side, because the heat that electric capacity produces is little, has strengthened Systems balanth when work.

For the device of setting forth among each embodiment of the utility model, all within spirit of the present utility model and principle, any modification of doing, be equal to replacement, improvement etc., all should be included within the protection domain of the present utility model.

Claims (6)

1. the lack detection circuit of a three-phase supply comprises: corresponding three bleeder circuits that connect three-phase, each described bleeder circuit connection rectification circuit separately, the triode testing circuit of three described rectification circuits connection detection default phase signal; It is characterized in that, each described bleeder circuit is made of electric capacity.

2. lack detection circuit according to claim 1 is characterized in that, the described electric capacity quantity of each described bleeder circuit is a plurality of, is connected in series.

3. lack detection circuit according to claim 1 is characterized in that, described rectification circuit is comprised of two diodes.

4. according to claim 1 or 3 described lack detection circuits, it is characterized in that, each described rectification circuit also connects filter capacitor and voltage stabilizing diode separately.

5. lack detection circuit according to claim 4 is characterized in that, also comprises three photoelectrical couplers;

Each described rectification circuit is connected one of them photoelectrical coupler by filter capacitor separately with voltage stabilizing diode;

The output terminal of three described photoelectrical couplers connects described triode testing circuit.

6. lack detection circuit according to claim 1 is characterized in that, described triode testing circuit comprises:

NPN type triode, detection terminal;

The base stage of described NPN type triode connects the output terminal of described three described photoelectrical couplers; The collector of described NPN type triode connects noble potential and described detection terminal; The emitter of described NPN type triode connects earth terminal.

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