CN1548965A - AC voltage under-voltage detecting circuit - Google Patents
AC voltage under-voltage detecting circuit Download PDFInfo
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- CN1548965A CN1548965A CNA031134068A CN03113406A CN1548965A CN 1548965 A CN1548965 A CN 1548965A CN A031134068 A CNA031134068 A CN A031134068A CN 03113406 A CN03113406 A CN 03113406A CN 1548965 A CN1548965 A CN 1548965A
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Abstract
The AC undervoltage detecting circuit can fast detect the fast drop in AC voltage and slowly detect the slow drop in AC voltage to ensure the UPS inverter to output AC voltage matching the requirement to the load. The AC undervoltage detecting circuit has bridge rectifier with output connected to both the input of the fast filter and the input of the slow filter, the output of the fast filter and the output of the slow filter connected separately to the input of the fast detection circuit and the slow detection circuit separately, the output of the fast detection circuit and the output of the slow detection circuit connected to the inputs of the or-gate, and D-trigger with input connected to the output of the or-gate and output Q as detection result.
Description
Technical field
The present invention relates to a kind of testing circuit, in particular, relate to a kind of ac voltage detection circuit.
Background technology
UPS is that uninterrupted power source must switch to bypass power supply with the requirement of proof load to power supply when inverter voltage is undesired.Inverter voltage changes and may drop into very low even to zero (as being reduced to zero in 1/4 cycle), also may slowly reduce (70--80% that is reduced to ratings as 5-10 cycle) from ratings moment.For former variant, load request UPS switches fast, and for the latter, load request UPS can be through switching behind the certain hour, to eliminate the small size misoperation that changes but do not need to switch of the inverter voltage that causes as load changing again.Usually the voltage analog in the uninterrupted power supply (ups) Unity is detected, adopt the method for step-down-rectification-filtering-threshold judgement basically.Its circuit is as shown in Figure 1: inverter voltage in step-down after after rectification, filtering become the very little DC voltage U of ripple factor, send into overvoltage comparator and under-voltage comparator.Adjust the allowable upper limit value that needs respectively and allow lower limit.Work as U
1＜U＜U
2The time, wherein: U
1Be the overvoltage threshold voltage, U is the voltage of voltage to be detected behind rectifying and wave-filtering, U
2It is under-voltage threshold voltage; Overvoltage comparator and under-voltage comparator are all exported high level, then detect and are output as " 0 ", and when U exceeded above-mentioned scope, promptly no matter voltage U was higher or on the low side, and the output of Sheffer stroke gate U1A is " 1 ".Because this circuit requirement dc ripple coefficient is little, so adopt the RC filter network time long, the output result has time-delay.After but inverter broke down, the general requirement of UPS detected in sinusoidal wave 1/4 cycle.The moment that above-mentioned voltage detecting circuit is difficult in fault detects the variation of voltage, and change-over switch can't be blocked inversion immediately and be switched to bypass supply and get on, thereby causes the intolerable output voltage of load to interrupt, and causes unnecessary loss.At present also have employing to utilize the method for digital signal processing to detect signal to be detected and model sinusoidal voltage waveform, but this method need CPU or dsp chip to handle cost height, complexity.Perhaps utilize CPU or DSP that the sine wave of taking a sample is carried out periodic sampling, several cycles (generally in order to prevent misoperation, the value of 5 left and right sides cycle 100ms that sample is averaged again) just can detect, can not be satisfied the requirement of computer load far away.
Summary of the invention
The present invention is in order to overcome weak point of the prior art, provide a kind of alternating voltage is significantly fallen fast to carry out fast detecting and descend by a small margin for a long time carrying out slow detection, the AC power that no matter inverter output voltage drops fast or slowly decline can both offer load of guaranteeing UPS meets the requirements, and simple in structure, the alternating voltage undervoltage detection circuit that cost is low.
The present invention is achieved through the following technical solutions:
A kind of alternating voltage undervoltage detection circuit, comprise rectifier bridge, input is connected the output of described rectifier bridge with slow filter with the input of fast electric-wave filter respectively, and the output of described fast electric-wave filter is connected with the input of fast detecting circuit, the output of described fast detecting circuit with or input be connected; The output of described slow filter is connected with the input of slow detection circuit, the output of described slow detection circuit with or the door input is connected, described or output be connected with the D pin of d type flip flop, the output Q of described d type flip flop provides the testing result signal.Rectifier bridge will sample AC rectification and become pulsating direct current, fast detecting circuit and slow filter that alternating voltage is significantly fallen fast to carry out fast detecting and descend by a small margin for a long time carrying out slow detection, the inverter output voltage of guaranteeing UPS no matter fast drop or slowly the decline AC power that can both offer load meet the requirements, as long as just or door and the D device that sets out represent drop fast or have in the decline one improperly to export under-voltage signal at a slow speed.Described fast electric-wave filter is formed the capacitance-resistance filter network by low capacity thin-film capacitor C1 and resistance R 1; Described fast detecting circuit adopts waveform threshold judgement mode, by thresholding one, thresholding two, thresholding three, phase inverter, positive-feedback circuit and resistance R 2, resistance R 4, capacitor C 3, resistance R 5, capacitor C 4 is formed, the anti-phase input TP1 of described thresholding one by resistance R 2 respectively with capacitor C 1, resistance R 1 connects, the in-phase input end of described thresholding one is a fixedly direct current threshold voltage TP2, the output TP3 of described thresholding one respectively with resistance R 4, the inverting input of capacitor C 3 and thresholding two connects, the other end of resistance R 4 is connected with the positive VCC of control power supply, and the other end of capacitor C 3 is connected with control power supply ground GND; The output terminal TP5 of described thresholding two is connected with the in-phase input end of resistance R 5, capacitor C 4 and thresholding three respectively, and the other end of resistance R 5 is connected with the positive VCC of control power supply, and the other end of capacitor C 4 is connected with control power supply ground GND; The output terminal TP7 of described thresholding three is connected with the input end of phase inverter; The output TP8 of described phase inverter respectively with or the door input and the input of positive-feedback circuit be connected; Described positive-feedback circuit is connected with the in-phase input end TP4 of described thresholding two and the in-phase input end TP6 of described thresholding three respectively.Described slow filter is made up of diode VD5, resistance R 3, resistance R 6, electrochemical capacitor C2; The anode of described diode VD5 is connected with the anti-phase input TP1 of described thresholding one, the negative electrode of described diode VD5 is connected with an end of resistance R 3, and the other end TP9 of resistance R 3 is connected with inverting input, resistance R 6 and an end of capacitor C 2 parallel connections of thresholding four respectively; The other end of resistance R 6, capacitor C 2 parallel connections is connected with the ground GND of control power supply.Described slow detection circuit is made up of thresholding four; The inverting input of described thresholding four is connected with an end TP9 of resistance R 3, one fixedly direct current threshold voltage TP10 connect the in-phase input end of thresholding four; The output TP11 of described thresholding four with or the door an input end be connected.Described thresholding is the open collector circuit.
The present invention has following beneficial effect:
The present invention can significantly fall fast alternating voltage and carry out fast detecting and descend by a small margin for a long time carrying out slow detection, the AC power that no matter inverter output voltage drops fast or slowly decline can both offer load of guaranteeing UPS meets the requirements, and simple in structure, cost is low.
Description of drawings
Fig. 1 is conventional ac voltage detection circuit figure;
Fig. 2 is the alternating voltage undervoltage detection circuit block diagram that is used for UPS of the present invention;
Fig. 3 is the alternating voltage undervoltage detection circuit figure that is used for UPS of the present invention;
Fig. 4 is key point oscillogram in the testing circuit of the present invention.
Embodiment
The invention will be further described below in conjunction with accompanying drawing.
As shown in Figure 2, a kind of alternating voltage undervoltage detection circuit comprises rectifier bridge, fast electric-wave filter and fast detecting circuit, slow filter and slow detection device circuit or door, d type flip flop.Rectifier bridge becomes pulsating direct current, fast detecting circuit and slow filter that alternating voltage is significantly fallen fast the AC rectification that samples to carry out fast detecting and descend by a small margin for a long time carrying out slow detection, the inverter output voltage of guaranteeing UPS no matter fast drop or slowly the decline AC power that can both offer load meet the requirements, as long as just or door and the D device that sets out represent drop fast or have in the decline one improperly to export under-voltage signal at a slow speed.Input is connected with slow filter with the input of fast electric-wave filter respectively for rectifier bridge output, and the output of described fast electric-wave filter is connected with the input of fast detecting circuit, the output of described fast detecting circuit with or input be connected; The output of described slow filter is connected with the input of slow detection circuit, the output of described slow detection circuit with or the door input is connected, described or output be connected with the D pin of d type flip flop, the output Q of described d type flip flop provides the testing result signal.
Physical circuit as shown in Figure 3, and is very little to the RC time constant design of the input filtering significantly fallen fast, almost filtering high frequency interference just; The rectified half-waves waveform is carried out threshold judgement; And it is bigger to the time constant design of the input filtering RC that slightly descends at a slow speed of inverter voltage.Wherein:
The full-bridge circuit that rectifier bridge is made up of 4 diode VD1, VD2, VD3, VD4;
Fast electric-wave filter is formed the capacitance-resistance filter network by low capacity thin-film capacitor C1 and resistance R 1;
The fast detecting circuit adopts waveform threshold judgement mode, is made up of thresholding one, thresholding two, thresholding three, phase inverter, positive-feedback circuit and resistance R 2, resistance R 4, capacitor C 3, resistance R 5, capacitor C 4.The anti-phase input TP1 of thresholding one is connected with capacitor C 1, resistance R 1 by resistance R 2, the in-phase input end of thresholding one is a fixedly direct current threshold voltage TP2, the output TP3 of thresholding one connects the inverting input of resistance R 4, capacitor C 3 and thresholding two, the other end of resistance R 4 connects the positive VCC of control power supply, and the other end of capacitor C 3 connects control power supply ground GND.The output terminal TP5 of thresholding two connects the in-phase input end of resistance R 5, capacitor C 4 and thresholding three, and the other end of resistance R 5 connects the positive VCC of control power supply, and the other end of capacitor C 4 connects control power supply ground GND.The output terminal TP7 of thresholding three connects the input end of phase inverter.The output TP8 of phase inverter connects or the input of door and the input of positive-feedback circuit.Positive-feedback circuit is connected with the in-phase input end TP4 of thresholding two and the in-phase input end TP6 of thresholding three respectively again.
Slow filter is made up of diode VD5, resistance R 3, resistance R 6, electrochemical capacitor C2.The anode of diode VD5 is connected with TP1, and the negative electrode of VD5 connects an end of resistance R 3, and the other end TP9 of resistance R 3 is connected with parallel resistor R6, capacitor C 2, and TP9 connects the inverting input of thresholding four simultaneously.The other end of resistance R 6, capacitor C 2 parallel connections connects the ground GND of control power supply.
The slow detection circuit is made up of thresholding four.TP9 connects the inverting input of thresholding four, one fixedly direct current threshold voltage TP10 connect the in-phase input end of thresholding four.The output TP11 connection of thresholding four or another input end of door.
Inverter voltage in the uninterrupted power supply (ups) Unity send the full-wave rectification bridge among the present invention to get the half-sinusoid signal through (voltage sampling input) after the step-down, through high frequency fast electric-wave filter R1, C1, filtering high frequency interference clutter, obtain a relative clean waveform, deliver to back fast detecting circuit and slow detection circuit;
In the fast detecting circuit, adopt the method for directly waveform being carried out threshold judgement, by three thresholdings and phase inverter and positive-feedback circuit, 2 draw resistance R 4, R5 and 2 capacitor C 3, C4 to constitute, thresholding all is the open collector circuit; Half-sinusoid TP1 behind the rectifying and wave-filtering and one are provided with threshold voltage TP2 and compare by thresholding one, as TP1 during greater than TP2, and thresholding one output low level, capacitor C 3 discharges.Otherwise as TP1 during less than TP2, thresholding output is high, and resistance R 4 gives capacitor C 3 chargings.When R4, C3 value to regularly, the voltage on the long more then capacitor C 3 of duration of charging is high more.In case TP1 is under-voltage significantly, then the duration of charging of C3 extends, when the voltage TP3 of C3 is higher than the threshold setting of thresholding two, thresholding two output low levels then, then the electric charge of capacitor C 4 bleeds off by thresholding two rapidly, and so thresholding 3 output low level TP7 then when C4 goes up voltage and is lower than the voltage of thresholding three are by high signal TP8 of output behind the phase inverter, by or the door remove to trigger d type flip flop, thereby provide switching signal TP12.Adopting capacitor C 4 in the invention and do not adopt resistance, is can prevent to disturb and misoperation.
Positive-feedback circuit among the present invention is that the electrical voltage point that promptly switches back again need exceed the electrical voltage point in original switching past to hysteresis of detected voltage signal.
Threshold setting among the present invention in the waveform threshold judgement circuit is: thresholding one with input voltage TP1 with specified standards when sinusoidal wave, in the one-period (10ms) in the half-sinusoid amplitude less than the zone of TP2 threshold setting for to be advisable less than 4ms.Thresholding two decides according to resistance R 4 and capacitor C 3, should make to detect to prevent to disturb the misoperation that causes fast again.The value of R4*C3 is with reference to be charged to 1/2V in 4ms
CCBe advisable.Thresholding three is less demanding, and a 1/2V is set
CCGet final product, mainly the waveform that thresholding two is come out carries out shaping.Phase inverter is the needs for steering logic.
The slow detection circuit that among the present invention alternating voltage is slightly descended at a slow speed is similar to general slow detection circuit, is made up of diode VD5, resistance R 3, R6, capacitor C 2, threshold setting TP10, the thresholding fourth class.Inverter voltage among the UPS gets the half-sinusoid signal through full-wave rectification after the step-down, and this signal is filtered into the less direct current signal TP9 of ripple factor through after the diode-isolated by R3, R6, C2 dividing potential drop.When this signal was lower than the threshold voltage TP10 of setting, thresholding four output TP11 were high level.Thresholding value and time constant filter R3*C2 are reference with the 70%--85% of normal alternating voltage 5-10 cycle of holding time.Certain positive feedback resistor is arranged in the thresholding four, give hysteresis of detected voltage, the electrical voltage point that promptly switches back again need exceed the electrical voltage point in original switching past.
Resistance R 7 and capacitor C 5 are the anti-tampering misoperation effect of exempting among the present invention.Fast detecting circuit output signal TP8 and slow detection circuit output signal TP11 form " or " relation, as long as that is to say significantly to fall fast or slightly descend at a slow speed has one to be detected, then control UPS and carry out the switching of inversion to bypass.
The frequency of the clock signal clk that the d type flip flop among the present invention needs is about 20kHz, can provide or design in addition a clock generating circuit by external circuit.
Fig. 4 is the detection waveform of key point among Fig. 3, further specifies principle of work of the present invention.
TP1 is a signal behind the detected voltage commutation among Fig. 4, and the 4th wave head of left-hand digit represents that moment descends fast.The right side descends at a slow speed after being illustrated in a normal wave head for a long time.
TP2, TP4 are respectively the threshold voltages that is provided with.
TP3 just often is a shorter and smaller sawtooth wave at detected voltage, in case voltage declines to a great extent suddenly, then sawtooth wave surpasses the threshold voltage of TP4.Long-term decline at a slow speed is a bigger sawtooth wave, but does not surpass the threshold voltage of TP4.
TP5 is at detected voltage high level just often, in case when voltage descended fast, capacitor C 4 discharged into when being lower than the TP6 threshold voltage, output TP7 is a high level.
TP9 is illustrated in detected voltage and descends at a slow speed that voltage is lower than the TP10 threshold voltage behind several ripples.It just often is low level that TP12 is illustrated in detected voltage, when detected electric voltage exception (comprise significantly to descend fast and moment descends at a slow speed), is high level.
Claims (2)
1. alternating voltage undervoltage detection circuit, comprise rectifier bridge, it is characterized in that, described rectifier bridge output is connected with slow filter input with the input of fast electric-wave filter respectively, the output of described fast electric-wave filter is connected with the input of fast detecting circuit, the output of described fast detecting circuit with or the door input be connected; The output of described slow filter is connected with the input of slow detection circuit, the output of described slow detection circuit with or the door input is connected, described or output be connected with the D pin of d type flip flop, the output Q of described d type flip flop provides the testing result signal; Described fast detecting circuit is used for alternating voltage significantly fallen fast and carries out fast detecting; Described slow filter is used for carrying out slow detection with descending by a small margin for a long time.
2. according to the described alternating voltage undervoltage detection circuit of claim 1, it is characterized in that:
Described fast electric-wave filter is formed the capacitance-resistance filter network by low capacity thin-film capacitor C1 and resistance R 1;
Described fast detecting circuit adopts waveform threshold judgement mode, by thresholding one, thresholding two, thresholding three, phase inverter, positive-feedback circuit and resistance R 2, resistance R 4, capacitor C 3, resistance R 5, capacitor C 4 is formed, the anti-phase input TP1 of described thresholding one by resistance R 2 respectively with capacitor C 1, resistance R 1 connects, the in-phase input end of described thresholding one is a fixedly direct current threshold voltage TP2, the output TP3 of described thresholding one respectively with resistance R 4, the inverting input of capacitor C 3 and thresholding two connects, the other end of resistance R 4 is connected with the positive VCC of control power supply, and the other end of capacitor C 3 is connected with control power supply ground GND; The output terminal TP5 of described thresholding two is connected with the in-phase input end of resistance R 5, capacitor C 4 and thresholding three respectively, and the other end of resistance R 5 is connected with the positive VCC of control power supply, and the other end of capacitor C 4 is connected with control power supply ground GND; The output terminal TP7 of described thresholding three is connected with the input end of phase inverter; The output TP8 of described phase inverter respectively with or the door input and the input of positive-feedback circuit be connected; Described positive-feedback circuit is connected with the in-phase input end TP4 of described thresholding two and the in-phase input end TP6 of described thresholding three respectively;
Described slow filter is made up of diode VD5, resistance R 3, resistance R 6, electrochemical capacitor C2; The anode of described diode VD5 is connected with the anti-phase input TP1 of described thresholding one, the negative electrode of described diode VD5 is connected with an end of resistance R 3, and the other end TP9 of resistance R 3 is connected with inverting input, resistance R 6 and an end of capacitor C 2 parallel connections of thresholding four respectively; The other end of resistance R 6, capacitor C 2 parallel connections is connected with the ground GND of control power supply;
Described slow detection circuit is made up of thresholding four; The inverting input of described thresholding four is connected with an end TP9 of resistance R 3, one fixedly direct current threshold voltage TP10 connect the in-phase input end of thresholding four; The output TP11 of described thresholding four with or the door an input end be connected;
Described thresholding is the open collector circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03113406 CN1260575C (en) | 2003-05-07 | 2003-05-07 | AC voltage under-voltage detecting circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03113406 CN1260575C (en) | 2003-05-07 | 2003-05-07 | AC voltage under-voltage detecting circuit |
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| CN1548965A true CN1548965A (en) | 2004-11-24 |
| CN1260575C CN1260575C (en) | 2006-06-21 |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102288809A (en) * | 2011-07-04 | 2011-12-21 | 隆鑫通用动力股份有限公司 | Voltmeter for measuring generating set |
| CN101738524B (en) * | 2008-11-19 | 2012-07-18 | 三星电子株式会社 | False signal eliminating circuit for low-voltage detection circuit |
| CN103036307A (en) * | 2012-11-28 | 2013-04-10 | 广州供电局有限公司 | Mains supply fault detection circuit and mains supply fault detection method and protective power supply emergency power supply system |
| CN104201643A (en) * | 2014-08-06 | 2014-12-10 | 潍坊歌尔电子有限公司 | Mains supply voltage protection circuit |
| CN104730323A (en) * | 2013-12-23 | 2015-06-24 | 珠海兴业节能科技有限公司 | AC voltage waveform distortion detection method and device |
| CN103364626B (en) * | 2012-03-26 | 2016-01-27 | 三垦电气株式会社 | AC-input voltage testing circuit |
| CN106768243A (en) * | 2016-12-15 | 2017-05-31 | 芯海科技（深圳）股份有限公司 | A kind of quick lock in accurate weight method |
| CN111007309A (en) * | 2019-12-30 | 2020-04-14 | 泛仕达机电股份有限公司 | Over-voltage and under-voltage detection method of variable frequency fan |
| CN112486022A (en) * | 2020-12-09 | 2021-03-12 | 国家电网有限公司 | Method and system for identifying variation trend of electrical quantity |
-
2003
- 2003-05-07 CN CN 03113406 patent/CN1260575C/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101738524B (en) * | 2008-11-19 | 2012-07-18 | 三星电子株式会社 | False signal eliminating circuit for low-voltage detection circuit |
| CN102288809A (en) * | 2011-07-04 | 2011-12-21 | 隆鑫通用动力股份有限公司 | Voltmeter for measuring generating set |
| CN103364626B (en) * | 2012-03-26 | 2016-01-27 | 三垦电气株式会社 | AC-input voltage testing circuit |
| CN103036307A (en) * | 2012-11-28 | 2013-04-10 | 广州供电局有限公司 | Mains supply fault detection circuit and mains supply fault detection method and protective power supply emergency power supply system |
| CN104730323A (en) * | 2013-12-23 | 2015-06-24 | 珠海兴业节能科技有限公司 | AC voltage waveform distortion detection method and device |
| CN104201643A (en) * | 2014-08-06 | 2014-12-10 | 潍坊歌尔电子有限公司 | Mains supply voltage protection circuit |
| CN106768243A (en) * | 2016-12-15 | 2017-05-31 | 芯海科技（深圳）股份有限公司 | A kind of quick lock in accurate weight method |
| CN106768243B (en) * | 2016-12-15 | 2019-03-05 | 芯海科技（深圳）股份有限公司 | A kind of quick lock in accurate weight method |
| CN111007309A (en) * | 2019-12-30 | 2020-04-14 | 泛仕达机电股份有限公司 | Over-voltage and under-voltage detection method of variable frequency fan |
| CN112486022A (en) * | 2020-12-09 | 2021-03-12 | 国家电网有限公司 | Method and system for identifying variation trend of electrical quantity |
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| Publication number | Publication date |
|---|---|
| CN1260575C (en) | 2006-06-21 |
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