CN102435828B - Isolated type circuit-voltage zero-crossing detecting circuit - Google Patents
Isolated type circuit-voltage zero-crossing detecting circuit Download PDFInfo
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- CN102435828B CN102435828B CN2011104396625A CN201110439662A CN102435828B CN 102435828 B CN102435828 B CN 102435828B CN 2011104396625 A CN2011104396625 A CN 2011104396625A CN 201110439662 A CN201110439662 A CN 201110439662A CN 102435828 B CN102435828 B CN 102435828B
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- 239000003990 capacitor Substances 0.000 claims abstract description 36
- 230000000087 stabilizing effect Effects 0.000 claims description 13
- 238000001514 detection method Methods 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 2
- 238000007599 discharging Methods 0.000 abstract 3
- 238000000034 method Methods 0.000 description 7
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
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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 refer to a kind of isolated type circuit-voltage zero-crossing detecting circuit.
Background technology
Along with the development of Power Electronic Technique, eliminate the harmonic wave of introducing electrical network, reduce System Reactive Power, accomplish electromagnetic compatibility, improve efficiency and the quality of energy conversion, more and more cause people's concern.In order to improve power factor, reduce system harmonics and idle, need to guarantee system network 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 meet the synchronous requirement of current/voltage.
The voltage comparator that current voltage zero-crossing detection circuit mainly consists of Hall element, operational amplifier, photoisolator etc. form, and mostly exist circuit cost higher, the uppity problem of dynamic parameter.As Fig. 1 is an exemplary voltages zero-crossing detection circuit commonly used at present.
Summary of the invention
The shortcoming that the object of the invention is to overcome above prior art, with not enough, provide a kind of easy low cost, is easy to the isolated type circuit-voltage zero-crossing detecting circuit of controlling, and adopts the simple components such as diode, electric capacity, triode to realize the detection of zero crossing.
The present invention is achieved through the following technical solutions:
A kind of isolated type circuit-voltage zero-crossing detecting circuit, comprise a photoisolator and a digital signal processor, characterized by further comprising a capacitor charging circuit and a capacitor discharge loop: described capacitor charging circuit is connected with described capacitor discharge loop, described capacitor discharge loop is connected with described photoisolator, described photoisolator is connected with described digital signal processor, by described photoisolator at input line voltage U
aBoutput negative edge trigger pip during zero crossing, and this signal is delivered to described digital signal processor capturing unit and processed.
Described capacitor charging circuit comprises the first diode, the 3rd diode, the first electric capacity and the first resistance; The external A phase voltage of the first diode anode wherein, the first diode negative terminal is connected with the first electric capacity upper end, and the other end of the first electric capacity is connected with the 3rd diode anode, and the first resistance one end is connected with the 3rd diode negative terminal, and the other end is connected to the B phase voltage.
In described capacitor charging circuit, the first electric capacity and voltage stabilizing diode are in parallel, and last charging voltage is stabilized in the voltage stabilizing value of voltage stabilizing diode; Described the first resistance is pressed line voltage value, to meet the charging current requirement.
Described capacitor discharge loop comprises the first electric capacity, the second resistance, the first triode and photoisolator light-emitting diode pipe end; Wherein the first electric capacity is connected with photoisolator light emitting diode anode, photoisolator light emitting diode negative terminal is connected to the second resistance one end, the second resistance other end is linked the first transistor collector, and the first transistor emitter is connected with the first electric capacity, and base stage is connected to the 3rd diode negative terminal; The value of described the first electric capacity and the second resistance directly affects the time of discharge process.
Described 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 is connected with the 3rd resistance, and the 3rd resistance other end is linked the 15V power supply, controlled transistor emitter ground connection.
Described digital signal processor is caught input end and is connected with the controlled transistor collector of photoisolator, waits the negative edge signal of input end to be captured, and when the negative edge signal occurs, digital signal processor cuts out timer internal, stores the current counter time.
Principle of the present invention: at first, as B phase voltage u
bbe less than A phase voltage u
athe time, capacitor charging circuit work, now the first electric capacity constantly charges until finally reach the voltage stabilizing value of voltage stabilizing diode, due to the 3rd diode current flow now, there is forward voltage drop, thereby cause the first transistor base voltage lower than emitter voltage, the first triode cut-off, photoisolator light-emitting diode pipe end no current passes through, the controlled triode cut-off of photoisolator, export high level under the effect of collector pull-up resistor, charging process can be determined by the resistance size that changes the first resistance the size of charging current, choosing of this resistance value should avoid charging current excessive.From the line voltage zero-cross point moment, B phase voltage u
bbecome and be greater than A phase voltage u
athe time, start working in the capacitor discharge loop, now the base voltage of the first triode is higher than emitter voltage, the first triode conducting, the first electric capacity is discharged by loop, photoisolator light emitting diode place, light emitting diode has electric current to pass through, the controlled triode conducting of photoelectrical coupler, and its output is dragged down, the negative edge signal of the input end to be captured such as described digital signal processor, now the negative edge signal occurs, digital signal processor cuts out timer internal, stores the current counter time.Along with the electric weight of the first electric capacity discharges, its both end voltage constantly reduces, when this undertension so that during the conducting of photoisolator light emitting diode, controlled triode cut-off in photoisolator, its output is drawn high by external pull-up resistor again, until B phase voltage u
bbe less than A phase voltage u
athe time, circuit is from newly being returned to initial state before.Visible according to this testing circuit principle of work, each cycle of line voltage 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 simple components such as diode, electric capacity, triode to realize the detection of zero crossing, simple in structure, has reduced circuit cost.
(2) in discharge loop of the present invention, due to the photoelectrical coupler light emitting diode and the first triode on resistance less, the discharge time constant of the first electric capacity is about R
2c
1, in the situation that the second resistance is selected, select the first electric capacity can determine discharge time constant, thus the capable of regulating photoisolator output low level time.
The accompanying drawing explanation
Fig. 1 is existing voltage zero-crossing detection circuit figure commonly used;
Fig. 2 is isolated type circuit-voltage zero-crossing detecting circuit figure of the present invention;
Fig. 3 is isolated type circuit-voltage zero-crossing detecting circuit workflow diagram of the present invention.
Embodiment
Below the specific embodiment of the present invention is described in further detail, but embodiments of the present invention are not limited to this.
As shown in Figure 2, isolated type circuit-voltage zero-crossing detecting circuit of the present invention, comprise a photoisolator and a digital signal processor, characterized by further comprising a capacitor charging circuit and a capacitor discharge loop: described capacitor charging circuit is connected with described capacitor discharge loop, described capacitor discharge loop is connected with described photoisolator, described photoisolator is connected with described digital signal processor, by described photoisolator at input line voltage U
aBoutput negative edge trigger pip during zero crossing, and this signal is delivered to described digital signal processor capturing unit and processed.
Described capacitor charging circuit comprises the first diode, the 3rd diode, the first electric capacity and the first resistance; The external A phase voltage of the first diode anode wherein, the first diode negative terminal is connected with the first electric capacity upper end, and the other end of the first electric capacity is connected with the 3rd diode anode, and the first resistance one end is connected with the 3rd diode negative terminal, and the other end is connected to the B phase voltage.
In described capacitor charging circuit, the first electric capacity and voltage stabilizing diode are in parallel, and last charging voltage is stabilized in the voltage stabilizing value of voltage stabilizing diode; Described the first resistance is pressed line voltage value, to meet the charging current requirement.
Described capacitor discharge loop comprises the first electric capacity, the second resistance, the first triode and photoisolator light-emitting diode pipe end; Wherein the first electric capacity is connected with photoisolator light emitting diode anode, photoisolator light emitting diode negative terminal is connected to the second resistance one end, the second resistance other end is linked the first transistor collector, and the first transistor emitter is connected with the first electric capacity, and base stage is connected to the 3rd diode negative terminal; The value of described the first electric capacity and the second resistance directly affects the time of discharge process.
Described 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 is connected with the 3rd resistance, and the 3rd resistance other end is linked the 15V power supply, controlled transistor emitter ground connection.
Described digital signal processor is caught input end and is connected with the controlled transistor collector of photoisolator, waits the negative edge signal of input end to be captured, and when the negative edge signal occurs, digital signal processor cuts out timer internal, stores the current counter time.
As shown in Figure 2,3.Line voltage is in a period of change, and this testing circuit will have following operational process: capacitor charging circuit is charged to the first electric capacity; The first electric capacity discharges electric energy by 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 described digital signal processor capturing unit and processed; The first electric capacity is put a little complete, and lock-on signal is from new reply high level until end cycle so far, completes a zero crossing detection.
As shown in Figure 2,3.As B phase voltage u
bbe less than A phase voltage u
athe time, A phase voltage u
aby the first diode D
1, the first capacitor C
1, the 3rd diode D
3, the first resistance R
1, A phase voltage u
ato the first capacitor C
1charging, (charging process can be determined by the resistance size that changes the first resistance the size of charging current, and the choosing of this resistance value should avoid the charging current excessive) the 3rd diode D
3pressure drop make the first triode Q
1cut-off, last the first capacitor C
1charging voltage is stabilized in the voltage stabilizing value of voltage stabilizing diode VD.Optocoupler U now
1light emitting diode cut-off, controlled triode also ends, the capture-outside input CAP of digital signal processor is pulled to high level.After zero crossing, B phase voltage u
bvoltage is greater than A phase voltage u
a, u
bby the first resistance R
1, the first triode Q
1base stage, the second diode D
2, u
aform path, the first triode Q
1conducting, the first capacitor C
1at short notice the electric discharge, (due to the photoelectrical coupler light emitting diode and the first triode on resistance less, the discharge time constant of the first electric capacity is about R
2c
1in the situation that the second resistance is selected, select the first electric capacity can determine discharge time constant, thereby the adjustment photoisolator low level output time) the light emitting diode conducting in photoisolator, controlled triode conducting, photoisolator output terminal CAP is pulled down to low level, thereby forms negative edge.In the first capacitor C
1the moment of electric 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 mentioned above, just can realize preferably the present invention.Above-described embodiment is only preferred embodiment of the present invention, not is used for limiting practical range of the present invention; Be that all equalizations of doing according to content of the present invention change and modify, all contained by the claims in the present invention scope required for protection.
Claims (2)
1. an isolated type circuit-voltage zero-crossing detecting circuit, comprise a photoisolator and a digital signal processor, characterized by further comprising a capacitor charging circuit and a capacitor discharge loop: described capacitor charging circuit is connected with described capacitor discharge loop, described capacitor discharge loop is connected with described photoisolator, described photoisolator is connected with described digital signal processor, by described photoisolator at input line voltage
output negative edge trigger pip during zero crossing, and this signal is delivered to described digital signal processor capturing unit and processed;
Described capacitor charging circuit comprises the first diode, the 3rd diode, the first electric capacity and the first resistance; Wherein the first diode anode is external
phase voltage, the first diode negative terminal is connected with the first electric capacity upper end, and the other end of the first electric capacity is connected with the 3rd diode anode, and the first resistance one end is connected with the 3rd diode negative terminal, and the other end is connected to
phase voltage;
In described capacitor charging circuit, the first electric capacity and voltage stabilizing diode are in parallel, and last charging voltage is stabilized in the voltage stabilizing value of voltage stabilizing diode; Described the first resistance is pressed line voltage value, to meet the charging current requirement;
Described capacitor discharge loop comprises the first electric capacity, the second resistance, the first triode and photoisolator light-emitting diode pipe end; Wherein an end of the first electric capacity is connected with photoisolator light emitting diode anode, photoisolator light emitting diode negative terminal is connected to the second resistance one end, the second resistance other end is linked the first transistor collector, the first transistor emitter is connected with the other end of the first electric capacity, and base stage is connected to the 3rd diode negative terminal;
Described 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 is connected with the 3rd resistance, and the 3rd resistance other end is linked the 15V power supply, controlled transistor emitter ground connection.
2. isolated type circuit-voltage zero-crossing detecting circuit according to claim 1, it is characterized in that: described digital signal processor is caught input end and is connected with the controlled transistor collector of photoisolator, negative edge signal etc. input end to be captured, when the negative edge signal occurs, 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 |
Applications Claiming Priority (1)
| 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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| Publication Number | Publication Date |
|---|---|
| CN102435828A CN102435828A (en) | 2012-05-02 |
| CN102435828B true CN102435828B (en) | 2013-11-13 |
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|---|---|---|---|
| CN2011104396625A Expired - Fee Related CN102435828B (en) | 2011-12-23 | 2011-12-23 | Isolated type circuit-voltage zero-crossing detecting circuit |
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Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| 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 |
| 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 |
| 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 |
| CN112305300B (en) * | 2019-07-31 | 2023-11-03 | 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 |
| CN113671277A (en) * | 2021-08-11 | 2021-11-19 | 都昌县百事网络信息服务有限公司 | Zero-crossing pulse counting phase-loss detection circuit |
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 |
-
2011
- 2011-12-23 CN CN2011104396625A patent/CN102435828B/en not_active Expired - Fee Related
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 |
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| CN102435828A (en) | 2012-05-02 |
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