CN102435828A - Isolated type circuit-voltage zero-crossing detecting circuit - Google Patents
Isolated type circuit-voltage zero-crossing detecting circuit Download PDFInfo
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- CN102435828A CN102435828A CN2011104396625A CN201110439662A CN102435828A CN 102435828 A CN102435828 A CN 102435828A CN 2011104396625 A CN2011104396625 A CN 2011104396625A CN 201110439662 A CN201110439662 A CN 201110439662A CN 102435828 A CN102435828 A CN 102435828A
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- photoisolator
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- electric capacity
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Abstract
The invention discloses an isolated type circuit-voltage zero-crossing detecting circuit and belongs to the technical field of electrics. The isolated type circuit-voltage zero-crossing detecting circuit comprises a capacitor charging circuit, a discharging loop/return circuit, a photoisolator and a capturing circuit of a digital signal processor, wherein an input end of the capacitor charging circuit is respectively connected to a phase A and a phase B of a three-phase voltage on a network side; an output end of the capacitor charging circuit is connected to a capacitor discharging loop/return circuit; and the discharging loop/return circuit is used for outputting zero-crossing information of a circuit voltage through the photoisolator and is connected to the input end of the capturing circuit of the digital signal processor, thereby obtaining accurate zero-crossing information. With a simple circuit structure, the isolated type circuit-voltage zero-crossing detecting circuit is used for realizing the zero-crossing detection, is successfully applied, is excellent in effect and is easily realized.
Description
Technical field
The present invention relates to the ac line voltage zero cross detection circuit of system power factor correcting control circuit, specifically be meant a kind of isolated line voltage zero-cross testing circuit.
Background technology
Along with the development of Power Electronic Technique, eliminate the harmonic wave of introducing electrical network, it is idle to reduce system, accomplishes electromagnetic compatibility, improves the efficient and the quality of energy conversion, more and more causes people's attention.In order to improve power factor; Reduce system harmonics and idle; Need assurance system's net side input current and input voltage same-phase, therefore need a kind of voltage over zero testing circuit to obtain voltage-phase, and then current phase is controlled to satisfy the synchronous requirement of current/voltage.
The voltage comparator that present voltage zero-crossing detection circuit mainly is made up of Hall element, operational amplifier, photoisolator etc. constitute, and mostly exist circuit cost higher, the uppity problem of dynamic parameter.Be an exemplary voltages zero-crossing detection circuit commonly used at present like Fig. 1.
Summary of the invention
The shortcoming that the objective of the invention is to overcome above prior art is with not enough, and the isolated line voltage zero-cross testing circuit that a kind of easy low cost is provided, is easy to control adopts simple components such as diode, electric capacity, triode to realize the detection of zero crossing.
The present invention realizes through following technical proposals:
A kind of isolated line voltage zero-cross testing circuit; Comprise a photoisolator and a digital signal processor; It is characterized in that also comprising a capacitor charging circuit and a capacitor discharge loop: said capacitor charging circuit is connected with said capacitor discharge loop; Said capacitor discharge loop is connected with said photoisolator, and described photoisolator is connected with described digital signal processor, by said photoisolator at input line voltage U
ABOutput negative edge trigger pip during zero crossing, and this signal is delivered to said digital signal processor capturing unit handle.
Said capacitor charging circuit comprises first diode, the 3rd diode, first electric capacity and first resistance; The external A phase voltage of the first diode anode wherein, the first diode negative terminal links to each other with first electric capacity upper end, and the other end of first electric capacity is connected with the 3rd diode anode, and first resistance, one end is connected with the 3rd diode negative terminal, and the other end is connected to the B phase voltage.
First electric capacity and voltage stabilizing diode are in parallel in the said capacitor charging circuit, and last charging voltage is stabilized in the voltage stabilizing value of voltage stabilizing diode; Said first resistance is pressed line voltage value, to satisfy the charging current requirement.
Said capacitor discharge loop comprises first electric capacity, second resistance, first triode and photoisolator light-emitting diode pipe end; Wherein first electric capacity links to each other with photoisolator light emitting diode anode; Photoisolator light emitting diode negative terminal is connected to second resistance, one end; The second resistance other end is then linked first transistor collector, and first transistor emitter links to each other with first electric capacity, and base stage then is connected to the 3rd diode negative terminal; The value of said first electric capacity and second resistance directly influences the time of discharge process.
Said photoisolator comprises a light emitting diode and a controlled triode; Controlled triode conducting is controlled by the break-make of light emitting diode whether; Controlled transistor collector links to each other with the 3rd resistance, and the 3rd resistance other end is linked the 15V power supply, controlled transistor emitter ground connection.
Said digital signal processor is caught input end and is linked to each other with the controlled transistor collector of photoisolator, waits for the negative edge signal of catching input end, and when the appearance of negative edge signal, digital signal processor cuts out timer internal, stores the current counter time.
Principle of the present invention: at first, as B phase voltage u
bLess than A phase voltage u
aThe time, capacitor charging circuit work, this moment first electric capacity constantly charging until the voltage stabilizing value that reaches voltage stabilizing diode at last; Because the 3rd diode current flow had forward voltage drop, thereby caused the first transistor base voltage to be lower than emitter voltage this moment; First triode ends; Photoisolator light-emitting diode pipe end no current passes through, and then the controlled triode of photoisolator ends, output high level under the effect of collector pull-up resistor; Charging process can be confirmed the size of charging current through the resistance size that changes first resistance, and choosing of this resistance value should avoid charging current excessive.From line voltage zero-cross point constantly, B phase voltage u
bBecome greater than A phase voltage u
aThe time, start working in the capacitor discharge loop, and this moment, the base voltage of first triode was higher than emitter voltage; The first triode conducting, first electric capacity discharges through loop, photoisolator light emitting diode place, and light emitting diode has electric current to pass through; The controlled triode conducting of photoelectrical coupler, its output is dragged down, and said digital signal processor is waited for the negative edge signal of catching input end; This moment, the negative edge signal occurred, and digital signal processor cuts out timer internal, stores the current counter time.Along with the electric weight of first electric capacity discharges, its voltage constantly reduces, so that during the conducting of photoisolator light emitting diode, controlled triode ends in the photoisolator, its output is drawn high by external pull-up resistor once more, until B phase voltage u when this undertension
bLess than A phase voltage u
aThe time, circuit is from newly being returned to initial state before.It is thus clear that according to this testing circuit principle of work, each cycle of line voltage all has a zero crossing can make photoisolator output produce a negative edge, and then is caught by digital signal processor.
Compared with prior art, the present invention has following advantage and beneficial effect:
(1) the present invention adopts the detection of simple components realization zero crossings such as diode, electric capacity, triode, and is simple in structure, reduced circuit cost.
(2) in the discharge loop of the present invention, because the photoelectrical coupler light emitting diode and first triode on resistance are less, the first capacitance discharges time constant is about R
2C
1, under the situation that second resistance has been selected, select first electric capacity can confirm discharge time constant, thus the adjustable lay the grain electric isolator output low level time.
Description of drawings
Fig. 1 is existing voltage zero-crossing detection circuit figure commonly used;
Fig. 2 is the isolated line voltage zero-cross testing circuit of the present invention figure;
Fig. 3 is the isolated line voltage zero-cross testing circuit of a present invention workflow diagram.
Embodiment
Following specific embodiments of the invention is done further detailed explanation, but embodiment of the present invention is not limited thereto.
As shown in Figure 2; The isolated line voltage zero-cross testing circuit of the present invention; Comprise a photoisolator and a digital signal processor, it is characterized in that also comprising a capacitor charging circuit and a capacitor discharge loop: said capacitor charging circuit is connected with said capacitor discharge loop, and said capacitor discharge loop is connected with said photoisolator; Described photoisolator is connected with described digital signal processor, by said photoisolator at input line voltage U
ABOutput negative edge trigger pip during zero crossing, and this signal is delivered to said digital signal processor capturing unit handle.
Said capacitor charging circuit comprises first diode, the 3rd diode, first electric capacity and first resistance; The external A phase voltage of the first diode anode wherein, the first diode negative terminal links to each other with first electric capacity upper end, and the other end of first electric capacity is connected with the 3rd diode anode, and first resistance, one end is connected with the 3rd diode negative terminal, and the other end is connected to the B phase voltage.
First electric capacity and voltage stabilizing diode are in parallel in the said capacitor charging circuit, and last charging voltage is stabilized in the voltage stabilizing value of voltage stabilizing diode; Said first resistance is pressed line voltage value, to satisfy the charging current requirement.
Said capacitor discharge loop comprises first electric capacity, second resistance, first triode and photoisolator light-emitting diode pipe end; Wherein first electric capacity links to each other with photoisolator light emitting diode anode; Photoisolator light emitting diode negative terminal is connected to second resistance, one end; The second resistance other end is then linked first transistor collector, and first transistor emitter links to each other with first electric capacity, and base stage then is connected to the 3rd diode negative terminal; The value of said first electric capacity and second resistance directly influences the time of discharge process.
Said photoisolator comprises a light emitting diode and a controlled triode; Controlled triode conducting is controlled by the break-make of light emitting diode whether; Controlled transistor collector links to each other with the 3rd resistance, and the 3rd resistance other end is linked the 15V power supply, controlled transistor emitter ground connection.
Said digital signal processor is caught input end and is linked to each other with the controlled transistor collector of photoisolator, waits for the negative edge signal of catching input end, and when the appearance of negative edge signal, digital signal processor cuts out timer internal, stores the current counter time.
Like Fig. 2, shown in 3.Line voltage is in a period of change, and this testing circuit will have following operational process: capacitor charging circuit charges to first electric capacity; First electric capacity discharges electric energy through discharge loop; Drive the photoisolator action in the electric energy dispose procedure; The photoisolator action causes the negative edge signal; Digital signal processor captures the negative edge trigger pip; And this signal is delivered to said digital signal processor capturing unit handle; First electric capacity is put a little and is finished, and lock-on signal, so far, is accomplished a zero crossing and detected until end cycle from new answer high level.
Like Fig. 2, shown in 3.As B phase voltage u
bLess than A phase voltage u
aThe time, A phase voltage u
aThrough the first diode D
1, first capacitor C
1, the 3rd diode D
3, first resistance R
1, A phase voltage u
aTo first capacitor C
1Charging, (charging process can be confirmed the size of charging current through the resistance size that changes first resistance, and the choosing of this resistance value should avoid the charging current excessive) the 3rd diode D
3Pressure drop make the first triode Q
1End last first capacitor C
1Charging voltage is stabilized in the voltage stabilizing value of voltage stabilizing diode VD.This moment optocoupler U
1Light emitting diode end, controlled triode also ends, the capture-outside of digital signal processor input CAP is pulled to high level.Through behind the zero crossing, B phase voltage u
bVoltage is greater than A phase voltage u
a, u
bThrough first resistance R
1, the first triode Q
1Base stage, the second diode D
2, u
aForm path, the first triode Q
1Conducting, first capacitor C
1Discharge at short notice, (because the photoelectrical coupler light emitting diode and first triode on resistance are less, the first capacitance discharges time constant is about R
2C
1Under the situation that second resistance has been selected; Select first electric capacity can confirm discharge time constant, thus adjustment photoisolator low level output time) light emitting diode conducting in the photoisolator, controlled triode conducting; Photoisolator output terminal CAP is pulled down to low level, thereby forms negative edge.In first capacitor C
1The moment of discharge, digital signal processor is caught the negative edge signal of input end, and digital signal processor cuts out timer internal, stores the current counter time.
As stated, just can realize the present invention preferably.The foregoing description is merely preferred embodiment of the present invention, is not to be used for limiting practical range of the present invention; Be that all equalizations of doing according to content of the present invention change and modification, all contained by claim of the present invention scope required for protection.
Claims (6)
1. isolated line voltage zero-cross testing circuit; Comprise a photoisolator and a digital signal processor; It is characterized in that also comprising a capacitor charging circuit and a capacitor discharge loop: said capacitor charging circuit is connected with said capacitor discharge loop; Said capacitor discharge loop is connected with said photoisolator, and described photoisolator is connected with described digital signal processor, by said photoisolator at input line voltage U
ABOutput negative edge trigger pip during zero crossing, and this signal is delivered to said digital signal processor capturing unit handle.
2. isolated line voltage zero-cross testing circuit according to claim 1 is characterized in that: said capacitor charging circuit comprises first diode, the 3rd diode, first electric capacity and first resistance; The external u of the first diode anode wherein
aPhase voltage, the first diode negative terminal links to each other with first electric capacity upper end, and the other end of first electric capacity is connected with the 3rd diode anode, and first resistance, one end is connected with the 3rd diode negative terminal, and the other end is connected to u
bPhase voltage.
3. isolated line voltage zero-cross testing circuit according to claim 1, it is characterized in that: first electric capacity and voltage stabilizing diode are in parallel in the said capacitor charging circuit, and last charging voltage is stabilized in the voltage stabilizing value of voltage stabilizing diode; Said first resistance is pressed line voltage value, to satisfy the charging current requirement.
4. isolated line voltage zero-cross testing circuit according to claim 1 is characterized in that: said capacitor discharge loop comprises first electric capacity, second resistance, first triode and photoisolator light-emitting diode pipe end; Wherein first electric capacity links to each other with photoisolator light emitting diode anode; Photoisolator light emitting diode negative terminal is connected to second resistance, one end; The second resistance other end is then linked first transistor collector, and first transistor emitter links to each other with first electric capacity, and base stage then is connected to the 3rd diode negative terminal.
5. isolated line voltage zero-cross testing circuit according to claim 1; It is characterized in that: said photoisolator comprises a light emitting diode and a controlled triode; Controlled triode conducting is controlled by the break-make of light emitting diode whether; Controlled transistor collector links to each other with the 3rd resistance, and the 3rd resistance other end is linked the 15V power supply, controlled transistor emitter ground connection.
6. isolated line voltage zero-cross testing circuit according to claim 1; It is characterized in that: said digital signal processor is caught input end and is linked to each other with the controlled transistor collector of photoisolator; The negative edge signal of input end is caught in wait; When the appearance of negative edge signal, digital signal processor cuts out timer internal, stores the current counter time.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104396625A CN102435828B (en) | 2011-12-23 | 2011-12-23 | Isolated type circuit-voltage zero-crossing detecting circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104396625A CN102435828B (en) | 2011-12-23 | 2011-12-23 | Isolated type circuit-voltage zero-crossing detecting circuit |
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| CN102435828A true CN102435828A (en) | 2012-05-02 |
| CN102435828B CN102435828B (en) | 2013-11-13 |
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| CN2011104396625A Active CN102435828B (en) | 2011-12-23 | 2011-12-23 | Isolated type circuit-voltage zero-crossing detecting circuit |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108169546A (en) * | 2017-12-29 | 2018-06-15 | 上海盐巴信息科技有限公司 | A kind of zero-crossing detection system of alternating current and the electronic equipment with the system |
| CN109991535A (en) * | 2019-04-19 | 2019-07-09 | 青岛亿联客信息技术有限公司 | A kind of flash on-off control system and its input flash detection circuit |
| CN110676949A (en) * | 2019-10-12 | 2020-01-10 | 天津大学 | Optical feedback circuit for self-tuning wireless power supply |
| WO2020211114A1 (en) * | 2019-04-19 | 2020-10-22 | 青岛亿联客信息技术有限公司 | Flash switch control system and input flash detection circuit thereof |
| CN112305300A (en) * | 2019-07-31 | 2021-02-02 | 株洲中车时代半导体有限公司 | Voltage detection sensor and system |
| CN109991535B (en) * | 2019-04-19 | 2024-04-30 | 青岛亿联客信息技术有限公司 | Flash switch control system and input flash detection circuit thereof |
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| US4151427A (en) * | 1977-07-15 | 1979-04-24 | Travin Lev V | High-voltage zero-crossing detector |
| EP0174518A1 (en) * | 1984-08-17 | 1986-03-19 | Fuji Photo Film Co., Ltd. | Zero-cross point detecting circuit |
| US5166549A (en) * | 1991-08-07 | 1992-11-24 | General Electric Company | Zero-voltage crossing detector for soft-switching devices |
| CN201765270U (en) * | 2010-08-27 | 2011-03-16 | 深圳长城开发科技股份有限公司 | Zero-crossing detection circuit of electric meter system |
| CN202583310U (en) * | 2011-12-23 | 2012-12-05 | 华南理工大学 | Isolated type circuit-voltage zero-crossing detecting circuit |
-
2011
- 2011-12-23 CN CN2011104396625A patent/CN102435828B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4151427A (en) * | 1977-07-15 | 1979-04-24 | Travin Lev V | High-voltage zero-crossing detector |
| EP0174518A1 (en) * | 1984-08-17 | 1986-03-19 | Fuji Photo Film Co., Ltd. | Zero-cross point detecting circuit |
| US5166549A (en) * | 1991-08-07 | 1992-11-24 | General Electric Company | Zero-voltage crossing detector for soft-switching devices |
| CN201765270U (en) * | 2010-08-27 | 2011-03-16 | 深圳长城开发科技股份有限公司 | Zero-crossing detection circuit of electric meter system |
| CN202583310U (en) * | 2011-12-23 | 2012-12-05 | 华南理工大学 | Isolated type circuit-voltage zero-crossing detecting circuit |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108169546A (en) * | 2017-12-29 | 2018-06-15 | 上海盐巴信息科技有限公司 | A kind of zero-crossing detection system of alternating current and the electronic equipment with the system |
| CN108169546B (en) * | 2017-12-29 | 2024-03-19 | 上海盐巴信息科技有限公司 | Zero-crossing detection system of alternating current and electronic equipment with same |
| CN109991535A (en) * | 2019-04-19 | 2019-07-09 | 青岛亿联客信息技术有限公司 | A kind of flash on-off control system and its input flash detection circuit |
| WO2020211114A1 (en) * | 2019-04-19 | 2020-10-22 | 青岛亿联客信息技术有限公司 | Flash switch control system and input flash detection circuit thereof |
| CN109991535B (en) * | 2019-04-19 | 2024-04-30 | 青岛亿联客信息技术有限公司 | Flash switch control system and input flash detection circuit thereof |
| CN112305300A (en) * | 2019-07-31 | 2021-02-02 | 株洲中车时代半导体有限公司 | Voltage detection sensor and system |
| CN110676949A (en) * | 2019-10-12 | 2020-01-10 | 天津大学 | Optical feedback circuit for self-tuning wireless power supply |
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| Publication number | Publication date |
|---|---|
| CN102435828B (en) | 2013-11-13 |
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