CN218630128U - Zero-crossing detection circuit - Google Patents
Zero-crossing detection circuit Download PDFInfo
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- CN218630128U CN218630128U CN202221979488.3U CN202221979488U CN218630128U CN 218630128 U CN218630128 U CN 218630128U CN 202221979488 U CN202221979488 U CN 202221979488U CN 218630128 U CN218630128 U CN 218630128U
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Abstract
The utility model relates to a zero cross detection circuit, including zero line input, live wire input, opto-coupler one and master control circuit, its characterized in that: the input end of the zero line and the input end of the live line are firstly connected with a rectifier bridge for rectification, then pass through a first optocoupler and finally are grounded to form a pulsating direct current circuit; the main control circuit is connected to the first optocoupler and used for detecting a zero point in the pulsating direct current circuit; the pulsating direct current circuit refers to a circuit from the output end of the rectifier bridge to the ground before the ground is grounded. Because alternating current is rectified into a pulsating direct current waveform, a light emitting diode in the first optocoupler does not emit light signals only at a zero point, and light signals can be emitted at the rest time, so that one level signal can be accurately output only at the zero point.
Description
Technical Field
The utility model relates to a power detects technical field, especially relates to a zero cross detection circuit.
Background
In electric products, a plurality of load control needs to use a zero-crossing point signal of a power supply as a control load reference foundation point. For example, in the control of the heating power of the heating assembly of the electric cooker, by intercepting a segment of the conduction of each electric wave period, that is, the conduction angle control, and by adjusting the size of the conduction angle, the heating power is controlled.
A full-wave cycle of the alternating current includes not only a positive half-wave but also a negative half-wave. The control of the existing control circuit to the strong current circuit is mostly realized by an optical coupler, and the optical coupler generally comprises a light emitting diode and a photoelectric switch. Because the light emitting diode does not emit light signals in the negative half waveform of the alternating current, the conventional simple zero-crossing detection circuit usually outputs level signals continuously in the negative half waveform. If it is required to accurately output a level signal only at the zero point and not output a signal at the negative half waveform, a more complicated circuit is required for identification.
Disclosure of Invention
An object of the utility model is to provide a simple structure's zero crossing detection circuit that can only export a level signal at zero point.
In order to solve the technical problem, the utility model provides a zero cross detection circuit, including zero line input, live wire input, opto-coupler one and master control circuit, its characterized in that: the input end of the zero line and the input end of the live line are firstly connected with a rectifier bridge for rectification, then pass through a first optocoupler and finally are grounded to form a pulsating direct current circuit; the main control circuit is connected to the first optocoupler and used for detecting a zero point in the pulsating direct current circuit; the pulsating direct current circuit refers to a circuit from the output end of the rectifier bridge to the ground before the output end of the rectifier bridge is grounded.
The utility model has the advantages that: because alternating current is rectified into a pulsating direct current waveform, a light emitting diode in the first optocoupler does not emit light signals only at a zero point, and light signals can be emitted at the rest time, so that one level signal can be accurately output only at the zero point.
Furthermore, the live wire input end and the zero line input end are respectively connected to the first input end and the second input end of the rectifier bridge, the output end of the rectifier bridge is connected to the first end of the first capacitor, the second end of the first capacitor is grounded, and the second end of the first capacitor is connected to the third input end of the rectifier bridge.
The beneficial effect of adopting the above further scheme is: the first capacitor can filter high-frequency components to form a more standard pulsating direct current waveform.
Further, the pulsating direct current circuit also comprises a switching circuit, and the switching circuit comprises a second optical coupler, a second resistor and a zero-crossing switch; the second optical coupler is connected with the first optical coupler in series; the positive input end of the second optocoupler is connected with a weak current positive electrode after passing through a second resistor; and the negative electrode input end of the second optocoupler is connected with the zero-crossing switch.
The beneficial effect of adopting the above further scheme is: the zero-cross switch is generally a switch controlled by a single chip microcomputer, the second optocoupler is switched on after the zero-cross switch is switched on, and the pulsating direct current circuit is switched on. The starting and stopping of the zero-crossing detection circuit are convenient to control.
Furthermore, a first resistor is also connected in series in the pulsating direct current circuit, and the first resistor is positioned between the output end of the rectifier bridge and the second optocoupler.
The beneficial effect of adopting the above further scheme is: the resistor I is used for voltage division, and only a small amount of voltage can be detected.
Further, the main control circuit comprises an NPN triode, a resistor III, a resistor IV, a resistor V, a resistor VI and a zero-crossing signal receiving end;
the positive output end of the first optocoupler is connected with a weak current positive electrode through a fourth resistor; the negative electrode output end of the second optocoupler is connected with a weak current negative electrode;
a base electrode of the NPN triode is connected with the positive electrode output end of the first optocoupler through a resistor six, a collector electrode of the NPN triode is connected with a weak current positive electrode through a resistor three, and an emitting electrode of the NPN triode is connected with a weak current negative electrode;
the resistor five is connected between the positive output end of the optocoupler I and the collector of the NPN triode;
and the collector of the NPN triode is connected with a zero-crossing signal receiving end.
The beneficial effect of adopting the further scheme is that: when the pulsating direct current circuit is in a positive half waveform, the first optocoupler is switched on, the base electrode of the NPN triode is in a low level, and the collector electrode of the NPN triode is in a high level. When the pulsating direct current circuit is at a zero point, the first optocoupler is closed, the base electrode of the NPN triode is at a high level, the collector electrode of the NPN triode is at a high level and a low level, and the collector electrode of the NPN triode is at a low level. Therefore, when the pulsating direct current circuit is at a zero point, the output of the receiving end of the signal passing through the zero point is low level, and the rest output high level. The whole structure is simple and reasonable.
Further, the main control circuit further comprises a second capacitor, and the second capacitor is connected between the zero-crossing signal receiving end and the weak current cathode.
The beneficial effect of adopting the further scheme is that: and the capacitor filters the waveform from the collector of the NPN triode to the receiving end of the zero-crossing signal.
Drawings
Fig. 1 is a circuit diagram of the present invention.
Detailed Description
The present invention will be further described with reference to the following embodiments.
As shown in fig. 1, this embodiment discloses a zero cross detection circuit, including zero line input 1, live wire input 2, opto-coupler 3 and master control circuit, its characterized in that: the input end 1 of the zero line and the input end 2 of the live line are firstly connected with a rectifier bridge 4 for rectification, then pass through an optocoupler I3 and finally are grounded to form a pulsating direct current circuit; the main control circuit is connected to the first optocoupler 3 and used for detecting a zero point in the pulsating direct current circuit; the pulsating direct current circuit refers to a circuit from the output end of the rectifier bridge 4 to the ground before the ground is grounded. Because alternating current is rectified into a pulsating direct current waveform, the light emitting diode in the optocoupler-3 does not emit light signals only at the zero point, and light signals can be emitted at the rest time, so that a level signal can be accurately output only at the zero point.
The live wire input end 2 and the zero line input end 1 are connected to a first input end and a second input end of the rectifier bridge 4 respectively, the output end of the rectifier bridge 4 is connected with a first end of the first capacitor 41, a second end of the first capacitor 41 is grounded, and the second end of the first capacitor 41 is connected with a third input end of the rectifier bridge 4. The first capacitor 41 can filter high-frequency components to form a more standard pulsating direct current waveform.
The pulsating direct current circuit further comprises a switching circuit, and the switching circuit comprises a second optocoupler 5, a second resistor 51 and a zero-crossing switch 52; the second optical coupler 5 is connected with the first optical coupler 3 in series; the positive input end of the optocoupler II 5 is connected with the weak current positive electrode after passing through a resistor II 51; and the negative electrode input end of the optocoupler II 5 is connected with a zero-crossing switch 52. The zero-cross switch 52 is generally a switch controlled by a single chip microcomputer, after the zero-cross switch is turned on, the optocoupler two 5 is turned on, and the pulsating direct current circuit is conducted. The starting and stopping of the zero-crossing detection circuit are convenient to control.
And a first resistor 6 is also connected in series in the pulsating direct current circuit, and the first resistor 6 is positioned between the output end of the rectifier bridge 4 and the second optocoupler 5. The first resistor 6 is used for voltage division, and only a small amount of voltage can be detected.
The main control circuit comprises an NPN triode 31, a resistor III 33, a resistor IV 34, a resistor V35, a resistor VI 36 and a zero-crossing signal receiving end 32; the positive output end of the optical coupler I3 is connected with a weak current positive electrode through a resistor IV 34; the negative electrode output end of the optocoupler II 5 is connected with a weak current negative electrode; the base electrode of the NPN triode 31 is connected with the positive electrode output end of the optocoupler I3 through a resistor VI 36, the collector electrode of the NPN triode 31 is connected with the weak current positive electrode through a resistor III 33, and the emitter electrode of the NPN triode 31 is connected with the weak current negative electrode; the resistor five 35 is connected between the positive output end of the optocoupler one 3 and the collector of the NPN triode 31; the collector of the NPN triode 31 is connected to the zero-crossing signal receiving terminal 32. When the pulsating direct current circuit is in a positive half waveform, the optocoupler I3 is turned on, the base of the NPN triode 31 is in a low level, and the collector of the NPN triode 31 is in a high level. When the pulsating direct current circuit is at a zero point, the optocoupler one 3 is closed, the base of the NPN triode 31 is at a high level, the collector of the NPN triode 31 is at a high level and a low level, and the collector of the NPN triode 31 is at a low level. Therefore, when the ripple dc circuit is at zero, the zero-crossing signal receiving terminal 32 outputs a low level, and the rest outputs a high level. The whole structure is simple and reasonable.
The main control circuit further comprises a second capacitor 37, and the second capacitor 37 is connected between the zero-crossing signal receiving end 32 and the weak current cathode. Capacitor two 37 filters the waveform from the collector of NPN transistor 31 to zero-cross signal receiving terminal 32.
Claims (6)
1. The utility model provides a zero cross detection circuit, includes zero line input (1), live wire input (2), opto-coupler (3) and master control circuit, its characterized in that: the zero line input end (1) and the live wire input end (2) are firstly connected with a rectifier bridge (4) for rectification, then pass through an optical coupler I (3), and finally are grounded to form a pulsating direct current circuit; and the main control circuit is connected to the optical coupler I (3) and is used for detecting a zero point in the pulsating direct current circuit.
2. A zero-crossing detection circuit as claimed in claim 1, characterized in that the live input (2) and the neutral input (1) are connected to a first input and a second input, respectively, of the rectifier bridge (4), the output of the rectifier bridge (4) is connected to a first terminal of a first capacitor (41), a second terminal of the first capacitor (41) is connected to ground, and the second terminal of the first capacitor (41) is connected to a third input of the rectifier bridge (4).
3. A zero-crossing detection circuit as claimed in claim 1, wherein the pulsating direct current circuit further comprises a switching circuit, and the switching circuit comprises a second optical coupler (5), a second resistor (51) and a zero-crossing switch (52); the second optical coupler (5) is connected with the first optical coupler (3) in series; the positive input end of the optocoupler II (5) is connected with the weak current positive electrode after passing through a resistor II (51); and the negative electrode input end of the optocoupler II (5) is connected with a zero-crossing switch (52).
4. A zero-crossing detection circuit as claimed in claim 3, wherein a first resistor (6) is further connected in series in the pulsating dc circuit, and the first resistor (6) is located between the output end of the rectifier bridge (4) and the second optocoupler (5).
5. A zero-crossing detection circuit as claimed in claim 3, wherein the main control circuit comprises an NPN triode (31), a resistor three (33), a resistor four (34), a resistor five (35), a resistor six (36) and a zero-crossing signal receiving terminal (32);
the positive output end of the optical coupler I (3) is connected with the weak current positive electrode through a resistor IV (34); the negative electrode output end of the optocoupler II (5) is connected with a weak current negative electrode;
the base electrode of the NPN triode (31) is connected with the positive electrode output end of the optocoupler I (3) through a resistor six (36), the collector electrode of the NPN triode (31) is connected with the weak current positive electrode through a resistor three (33), and the emitter electrode of the NPN triode (31) is connected with the weak current negative electrode;
the resistor five (35) is connected between the positive output end of the optocoupler one (3) and the collector of the NPN triode (31);
and the collector of the NPN triode (31) is connected with a zero-crossing signal receiving end (32).
6. A zero-crossing detection circuit as claimed in claim 5, wherein the master control circuit further comprises a second capacitor (37), and the second capacitor (37) is connected between the zero-crossing signal receiving terminal (32) and the weak current negative pole.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221979488.3U CN218630128U (en) | 2022-07-27 | 2022-07-27 | Zero-crossing detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202221979488.3U CN218630128U (en) | 2022-07-27 | 2022-07-27 | Zero-crossing detection circuit |
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| CN218630128U true CN218630128U (en) | 2023-03-14 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202221979488.3U Active CN218630128U (en) | 2022-07-27 | 2022-07-27 | Zero-crossing detection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116667266A (en) * | 2023-07-21 | 2023-08-29 | 烟台东方威思顿电气有限公司 | High-reliability special transformer acquisition terminal |
-
2022
- 2022-07-27 CN CN202221979488.3U patent/CN218630128U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116667266A (en) * | 2023-07-21 | 2023-08-29 | 烟台东方威思顿电气有限公司 | High-reliability special transformer acquisition terminal |
| CN116667266B (en) * | 2023-07-21 | 2023-10-20 | 烟台东方威思顿电气有限公司 | High-reliability special transformer acquisition terminal |
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