CN107345989B - Open-phase detection circuit of three-phase input power supply - Google Patents
Open-phase detection circuit of three-phase input power supply Download PDFInfo
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- CN107345989B CN107345989B CN201710656273.5A CN201710656273A CN107345989B CN 107345989 B CN107345989 B CN 107345989B CN 201710656273 A CN201710656273 A CN 201710656273A CN 107345989 B CN107345989 B CN 107345989B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
- G01R29/16—Measuring asymmetry of polyphase networks
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/40—Testing power supplies
- G01R31/42—AC power supplies
Abstract
The invention provides a phase-failure detection circuit of a three-phase input power supply, which comprises a signal conversion circuit, a self-locking circuit and an output circuit, wherein the signal conversion circuit is used for converting the input voltage of the three-phase input power supply into a level signal; the self-locking circuit is used for locking the high-level signal; the output circuit is used for outputting a level signal; the input end of the signal conversion circuit is connected with a three-phase power supply, the output end of the signal conversion circuit is connected with the input end of the self-locking circuit, and the output end of the self-locking circuit is connected with the input end of the output circuit. When the three-phase voltage input is normal, the output circuit outputs a low level; if any one phase voltage in the three-phase voltage of the external three-phase alternating current is powered down or is in phase failure, the output circuit continuously outputs high level and locks, and whether the power supply is in phase failure is detected by observing the output level signal of the output circuit. The invention has the advantages of simple circuit, rapid detection, accuracy, reliability, strong anti-interference capability and good application prospect.
Description
Technical Field
The invention relates to the field of circuit detection, in particular to a phase-failure detection circuit of a three-phase input power supply.
Background
Because of the reason of the power grid or unreliable power input wiring, the switching power supply sometimes has the condition of open-phase operation, and the open-phase operation is not easy to find. When the power supply is in open-phase operation, one arm of the rectifier bridge has no current, and other arms can be damaged due to serious overcurrent, and meanwhile, the inverter works abnormally, so that the open-phase must be protected.
The current transformer or the electronic phase-loss detection circuit is generally adopted for detecting the phase loss of the power grid, and the electronic phase-loss protection circuit is generally adopted in the switching power supply because of high cost and large volume of the current transformer. The general electronic open-phase protection circuit is complex, other devices are needed to be matched for use, the cost is high, and the reliability is low.
Disclosure of Invention
In order to solve the technical problems, the invention aims to provide a phase failure detection circuit of a three-phase input power supply, which has the advantages of simple structure, rapid detection, accuracy, reliability and strong anti-interference capability.
In order to achieve the above object, the present invention provides a phase-failure detection circuit of a three-phase input power supply, which comprises a signal conversion circuit 1, a self-locking circuit 2 and an output circuit 3, wherein the signal conversion circuit 1 is used for converting input voltage of the three-phase input power supply into a level signal; the self-locking circuit 2 is used for locking the high-level signal; the output circuit 3 is used for outputting a level signal; the input end of the signal conversion circuit 1 is connected with a three-phase power supply, the output end of the signal conversion circuit is connected with the input end of the self-locking circuit 2, the output end of the self-locking circuit 2 is connected with the input end of the output circuit 3, the output circuit 3 comprises an optocoupler V4, a diode D5, a capacitor C5 and resistors R18 and R19, one end of the resistor R18 is connected with 12 power supply voltage, and the other end of the resistor R18 is connected with the anode of the optocoupler V4; the collector of the optocoupler V4 is connected with 5V power supply voltage, and the emitter of the optocoupler V is grounded through a capacitor C5; the resistor R19 is connected in parallel with two ends of the capacitor C5; the cathode of the diode D5 is connected with the cathode of the optocoupler V4, and the anode of the diode D is connected with the output end of the self-locking circuit 2.
Specifically, the signal conversion circuit 1 includes a branch A, B and a branch C, where the branch a includes an optocoupler V1, a diode D1, and an operational amplifier U4, one end of a resistor R1 is connected to an a phase of a three-phase power supply, the other end of the resistor R1 is connected to an anode of the optocoupler V1 through the resistor R4, and a collector of the optocoupler V1 is connected to a non-inverting input end of the operational amplifier U4; the anode of the diode D1 is connected with the cathode of the optocoupler V1, and the cathode of the diode D1 is connected with the anode of the optocoupler V1; the branch B comprises an optocoupler V2, a diode D2 and an operational amplifier U3, one end of a resistor R2 is connected with the phase B voltage of the power supply, the other end of the resistor R2 is connected with the anode of the optocoupler V2 through a resistor R5, and the collector of the optocoupler V2 is connected with the non-inverting input end of the operational amplifier U2; the anode of the diode D2 is connected with the cathode of the optocoupler V2, and the cathode of the diode D2 is connected with the anode of the optocoupler V2; the branch circuit C comprises an optocoupler V3, a diode D3 and an operational amplifier U3, one end of a resistor R3 is connected with the C-phase voltage of the power supply, the other end of the resistor R3 is connected with the anode of the optocoupler V3 through a resistor R6, and the collector of the optocoupler V3 is connected with the in-phase input end of the operational amplifier U3; the anode of the diode D3 is connected with the cathode of the optocoupler V3, and the cathode of the diode D3 is connected with the anode of the optocoupler V3; cathodes of the optocouplers V1, V2 and V3 are connected, one end of a resistor R7 is connected with 12V power supply voltage, and the other end of the resistor R7 is connected with a collector of the optocoupler V1; one end of the resistor R8 is connected with 12V power supply voltage, and the other end of the resistor R8 is connected with the collector electrode of the optocoupler V2; one end of the resistor R9 is connected with 12V power supply voltage, and the other end of the resistor R9 is connected with the collector electrode of the optocoupler V3; one end of a resistor R10 is connected with 12V power supply voltage, the other end of the resistor R is grounded through a resistor R11, and a capacitor C1 is connected in parallel with two ends of the resistor R11; the inverting input ends of the operational amplifiers U4, U2 and U3 are connected with nodes between the resistors R10 and R11; one end of the resistor R12 is connected with 12V power supply voltage, and the other end of the resistor R is grounded through the capacitor C2; the output ends of the operational amplifiers U4, U2 and U3 are connected with nodes between the resistor R12 and the capacitor C2; the output end of the operational amplifier U4 is connected with the input end of the self-locking circuit 2.
Specifically, the self-locking circuit 2 includes a triode Q1, an operational amplifier U1, a diode D4, and capacitors C3 and C4, where the base of the triode Q1 is connected to the output ends of the operational amplifiers U4, U2, and U3, the collector is connected to a 12V supply voltage via R13, and the emitter is grounded; the inverting input end of the operational amplifier U1 is connected with the collector electrode of the triode Q1, and the non-inverting input end of the operational amplifier U1 is connected with 12V power supply voltage through a resistor R15 and is grounded through a resistor R16; one end of the capacitor C3 is connected with the positive power supply end of the operational amplifier U1, and the other end of the capacitor C is grounded; the capacitor C4 is connected in parallel with two ends of the capacitor C3; one end of the resistor R14 is connected with the inverting input end of the operational amplifier U1, and the other end of the resistor R is grounded; one end of the resistor R17 is connected with 12V power supply voltage, and the other end of the resistor R is connected with the output end of the operational amplifier U1; the anode of the diode D4 is connected with the output end of the operational amplifier U1, and the cathode of the diode D is connected with the non-inverting input end of the operational amplifier U1; the output terminal of the operational amplifier U1 is connected with the anode of the diode D5.
As can be seen from the above technical scheme, the invention provides a phase-failure detection circuit of a three-phase input power supply, which comprises a signal conversion circuit, a self-locking circuit and an output circuit, wherein the input end of the signal conversion circuit is connected with the three-phase power supply, the output end of the signal conversion circuit is connected with the input end of the self-locking circuit, and the output end of the self-locking circuit is connected with the input end of the output circuit; the circuit has the advantages of simple structure, quick and accurate inspection, strong anti-interference capability and higher stability.
Drawings
Fig. 1 is a schematic diagram of a phase loss detection circuit of a three-phase input power supply according to the present invention.
Fig. 2 is a waveform diagram of the base voltage of the transistor Q1 when the open-phase detection circuit of the three-phase input power supply of the present invention is open-phase.
Detailed Description
The invention will be further described with reference to the accompanying drawings:
the embodiment of the invention shown in fig. 1 is a phase-failure detection circuit of a three-phase input power supply, which comprises a signal conversion circuit 1, a self-locking circuit 2 and an output circuit 3, wherein the signal conversion circuit 1 is used for converting the input voltage of the three-phase input power supply into a level signal; the self-locking circuit 2 is used for locking the high-level signal; the output circuit 3 is used for outputting a level signal; the input end of the signal conversion circuit 1 is connected with a three-phase power supply, the output end of the signal conversion circuit is connected with the input end of the self-locking circuit 2, the output end of the self-locking circuit 2 is connected with the input end of the output circuit 3, the output circuit 3 comprises an optocoupler V4, a zener diode D5, a capacitor C5 and resistors R18 and R19, one end of the resistor R18 is connected with 12 power supply voltage, and the other end of the resistor R18 is connected with the anode of the optocoupler V4; the collector of the optocoupler V4 is connected with 5V power supply voltage, and the emitter of the optocoupler V is grounded through a capacitor C5; the resistor R19 is connected in parallel with two ends of the capacitor C5; the cathode of the zener diode D5 is connected with the cathode of the optocoupler V4, and the anode of the zener diode D is connected with the output end of the self-locking circuit 2.
The signal conversion circuit 1 comprises a branch A, B and a branch C, wherein the branch A comprises an optocoupler V1, a diode D1 and an operational amplifier U4, one end of a resistor R1 is connected with an A phase of a three-phase power supply, the other end of the resistor R1 is connected with an anode of the optocoupler V1 through the resistor R4, and a collector of the optocoupler V1 is connected with a non-inverting input end of the operational amplifier U4; the anode of the diode D1 is connected with the cathode of the optocoupler V1, and the cathode of the diode D1 is connected with the anode of the optocoupler V1; the branch B comprises an optocoupler V2, a diode D2 and an operational amplifier U3, one end of a resistor R2 is connected with the phase B voltage of the power supply, the other end of the resistor R2 is connected with the anode of the optocoupler V2 through a resistor R5, and the collector of the optocoupler V2 is connected with the non-inverting input end of the operational amplifier U2; the anode of the diode D2 is connected with the cathode of the optocoupler V2, and the cathode of the diode D2 is connected with the anode of the optocoupler V2; the branch circuit C comprises an optocoupler V3, a diode D3 and an operational amplifier U3, one end of a resistor R3 is connected with the C-phase voltage of the power supply, the other end of the resistor R3 is connected with the anode of the optocoupler V3 through a resistor R6, and the collector of the optocoupler V3 is connected with the in-phase input end of the operational amplifier U3; the anode of the diode D3 is connected with the cathode of the optocoupler V3, and the cathode of the diode D3 is connected with the anode of the optocoupler V3; cathodes of the optocouplers V1, V2 and V3 are connected, one end of a resistor R7 is connected with 12V power supply voltage, and the other end of the resistor R7 is connected with a collector of the optocoupler V1; one end of the resistor R8 is connected with 12V power supply voltage, and the other end of the resistor R8 is connected with the collector electrode of the optocoupler V2; one end of the resistor R9 is connected with 12V power supply voltage, and the other end of the resistor R9 is connected with the collector electrode of the optocoupler V3; one end of a resistor R10 is connected with 12V power supply voltage, the other end of the resistor R is grounded through a resistor R11, and a capacitor C1 is connected in parallel with two ends of the resistor R11; the inverting input ends of the operational amplifiers U4, U2 and U3 are connected with nodes between the resistors R10 and R11; one end of the resistor R12 is connected with 12V power supply voltage, and the other end of the resistor R is grounded through the capacitor C2; the output ends of the operational amplifiers U4, U2 and U3 are connected with nodes between the resistor R12 and the capacitor C2; the output end of the operational amplifier U4 is connected with the input end of the self-locking circuit 2. The optocouplers V1, V2 and V3 in the three branches can isolate the high voltage of the three-phase mains supply from the power supply signal, ensure the safety of the circuit and improve the anti-interference capability of the circuit.
The self-locking circuit 2 comprises a triode Q1, an operational amplifier U1, a diode D4 and capacitors C3 and C4, wherein the base electrode of the triode Q1 is connected with the output ends of the operational amplifiers U4, U2 and U3, the collector electrode of the triode Q1 is connected with 12V power supply voltage through R13, and the emitter electrode of the triode Q is grounded; the inverting input end of the operational amplifier U1 is connected with the collector electrode of the triode Q1, and the non-inverting input end of the operational amplifier U1 is connected with 12V power supply voltage through a resistor R15 and is grounded through a resistor R16; one end of the capacitor C3 is connected with the positive power supply end of the operational amplifier U1, and the other end of the capacitor C is grounded; the capacitor C4 is connected in parallel with two ends of the capacitor C3; one end of the resistor R14 is connected with the inverting input end of the operational amplifier U1, and the other end of the resistor R is grounded; one end of the resistor R17 is connected with 12V power supply voltage, and the other end of the resistor R is connected with the output end of the operational amplifier U1; the anode of the diode D4 is connected with the output end of the operational amplifier U1, and the cathode of the diode D is connected with the non-inverting input end of the operational amplifier U1; the output end of the operational amplifier U1 is connected with the anode of the zener diode D5.
The working principle of this embodiment is as follows:
when the external three-phase alternating current is normal, the optocoupler V1 and the optocoupler V1 are conducted in turn, the base electrode of the triode Q1 is always in a low level, the triode Q1 is not conducted, the output end of the operational amplifier U1 is in a low level, the voltage stabilizing diode D5 plays a role in stabilizing voltage, the optocoupler V4 is conducted, and the emitter electrode of the voltage stabilizing diode D is in a low level, namely the alarm signal PH_FAULT.
Any one phase voltage of three-phase voltages of external three-phase alternating current is powered down or phase-lost, and triode Q1As shown in fig. 2. Assuming that the line voltage is U only when the C phase is absent AB When U AB At the vicinity of the zero crossing point, all three optocouplers are not conducted, at the moment, the base electrode of the triode Q1 is high level, the collector electrode and the emitter electrode of the triode are conducted, the inverting input end of the operational amplifier U1 is low level, the output end of the operational amplifier U1 is high level and is locked through the diode D4, so that the output end of the operational amplifier U1 continuously outputs high level, the locking alarm signal PH_FAULT is high level, after power is off and FAULTs are removed, the circuit is powered on again, the circuit is normal, the operational amplifier U1 outputs low level, and the alarm signal PH_FAULT is restored to low level.
By observing the level signal of the alarm signal PH_FAULT, the open-phase or not of the three-phase input power supply can be accurately detected.
The phase-loss detection circuit of the three-phase input power supply can accurately and timely detect whether the three-phase input power supply is in phase-loss. Compared with a common electronic open-phase protection circuit, the circuit in the embodiment has the advantages of simple structure, low cost, no need of other devices or software calculation, rapid detection, accurate result, high reliability and strong anti-interference capability, and has good application prospect.
The above examples are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection defined by the claims of the present invention without departing from the spirit of the present invention.
Claims (1)
1. A three-phase input power open-phase detection circuit is characterized in that: the power supply circuit comprises a signal conversion circuit (1), a self-locking circuit (2) and an output circuit (3), wherein the signal conversion circuit (1) is used for converting three-phase power supply input voltage into a level signal; the self-locking circuit (2) is used for locking the high-level signal; the output circuit (3) is used for outputting a level signal; the input end of the signal conversion circuit (1) is connected with a three-phase power supply, the output end of the signal conversion circuit is connected with the input end of the self-locking circuit (2), the output end of the self-locking circuit (2) is connected with the input end of the output circuit (3), the output circuit (3) comprises an optocoupler V4, a diode D5, a capacitor C5 and resistors R18 and R19, one end of the resistor R18 is connected with 12 power supply voltage, and the other end of the resistor R18 is connected with the anode of the optocoupler V4; the collector of the optocoupler V4 is connected with 5V power supply voltage, and the emitter of the optocoupler V is grounded through a capacitor C5; the resistor R19 is connected in parallel with two ends of the capacitor C5; the cathode of the diode D5 is connected with the cathode of the optocoupler V4, and the anode of the diode D is connected with the output end of the self-locking circuit (2);
the signal conversion circuit (1) comprises a branch A, B and a branch C, wherein the branch A comprises an optocoupler V1, a diode D1 and an operational amplifier U4, one end of a resistor R1 is connected with an A phase of a three-phase power supply, the other end of the resistor R1 is connected with an anode of the optocoupler V1 through the resistor R4, and a collector of the optocoupler V1 is connected with a non-inverting input end of the operational amplifier U4; the anode of the diode D1 is connected with the cathode of the optocoupler V1, and the cathode of the diode D1 is connected with the anode of the optocoupler V1; the branch B comprises an optocoupler V2, a diode D2 and an operational amplifier U3, one end of a resistor R2 is connected with the phase B voltage of the power supply, the other end of the resistor R2 is connected with the anode of the optocoupler V2 through a resistor R5, and the collector of the optocoupler V2 is connected with the non-inverting input end of the operational amplifier U2; the anode of the diode D2 is connected with the cathode of the optocoupler V2, and the cathode of the diode D2 is connected with the anode of the optocoupler V2; the branch circuit C comprises an optocoupler V3, a diode D3 and an operational amplifier U3, one end of a resistor R3 is connected with the C-phase voltage of the power supply, the other end of the resistor R3 is connected with the anode of the optocoupler V3 through a resistor R6, and the collector of the optocoupler V3 is connected with the in-phase input end of the operational amplifier U3; the anode of the diode D3 is connected with the cathode of the optocoupler V3, and the cathode of the diode D3 is connected with the anode of the optocoupler V3; cathodes of the optocouplers V1, V2 and V3 are connected, one end of a resistor R7 is connected with 12V power supply voltage, and the other end of the resistor R7 is connected with a collector of the optocoupler V1; one end of the resistor R8 is connected with 12V power supply voltage, and the other end of the resistor R8 is connected with the collector electrode of the optocoupler V2; one end of the resistor R9 is connected with 12V power supply voltage, and the other end of the resistor R9 is connected with the collector electrode of the optocoupler V3; one end of a resistor R10 is connected with 12V power supply voltage, the other end of the resistor R is grounded through a resistor R11, and a capacitor C1 is connected in parallel with two ends of the resistor R11; the inverting input ends of the operational amplifiers U4, U2 and U3 are connected with nodes between the resistors R10 and R11; one end of the resistor R12 is connected with 12V power supply voltage, and the other end of the resistor R is grounded through the capacitor C2; the output ends of the operational amplifiers U4, U2 and U3 are connected with nodes between the resistor R12 and the capacitor C2; the output ends of the operational amplifiers U4, U2 and U3 are connected with the input end of the self-locking circuit (2);
the self-locking circuit (2) comprises a triode Q1, an operational amplifier U1, a diode D4 and capacitors C3 and C4, wherein the base electrode of the triode Q1 is connected with the output ends of the operational amplifiers U4, U2 and U3, the collector electrode of the triode is connected with 12V power supply voltage through R13, and the emitter electrode of the triode is grounded; the inverting input end of the operational amplifier U1 is connected with the collector electrode of the triode Q1, and the non-inverting input end of the operational amplifier U1 is connected with 12V power supply voltage through a resistor R15 and is grounded through a resistor R16; one end of the capacitor C3 is connected with the positive power supply end of the operational amplifier U1, and the other end of the capacitor C is grounded; the capacitor C4 is connected in parallel with two ends of the capacitor C3; one end of the resistor R14 is connected with the inverting input end of the operational amplifier U1, and the other end of the resistor R is grounded; one end of the resistor R17 is connected with 12V power supply voltage, and the other end of the resistor R is connected with the output end of the operational amplifier U1; the anode of the diode D4 is connected with the output end of the operational amplifier U1, and the cathode of the diode D is connected with the non-inverting input end of the operational amplifier U1; the output terminal of the operational amplifier U1 is connected with the anode of the diode D5.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710656273.5A CN107345989B (en) | 2017-08-03 | 2017-08-03 | Open-phase detection circuit of three-phase input power supply |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201710656273.5A CN107345989B (en) | 2017-08-03 | 2017-08-03 | Open-phase detection circuit of three-phase input power supply |
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| CN107345989B true CN107345989B (en) | 2023-05-23 |
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| CN2595041Y (en) * | 2003-01-15 | 2003-12-24 | 尹修平 | Intelligent protector of motor |
| WO2013044602A1 (en) * | 2011-09-30 | 2013-04-04 | 海信科龙电器股份有限公司 | Zero-crossing signal detection circuit |
| CN203982473U (en) * | 2014-08-01 | 2014-12-03 | 重庆宁来科贸有限公司 | Arrangements for automotive doors drops into a kind of locking device of conversion automatically |
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