CN217404498U - Circuit for rapidly detecting single-phase alternating current power supply signal - Google Patents
Circuit for rapidly detecting single-phase alternating current power supply signal Download PDFInfo
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- CN217404498U CN217404498U CN202121245819.6U CN202121245819U CN217404498U CN 217404498 U CN217404498 U CN 217404498U CN 202121245819 U CN202121245819 U CN 202121245819U CN 217404498 U CN217404498 U CN 217404498U
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Abstract
The invention relates to a circuit for rapidly detecting a single-phase alternating current power supply signal, which comprises two wiring terminals, two optocouplers U1-U2, a resistor R2, a phase shifter and two rectifier bridges D1-D2, wherein the optocouplers U1-U2 are connected with the resistor R2; the two connecting terminals are respectively used for butting an L line and an N line of a single-phase alternating-current power supply, one connecting terminal is respectively connected with one input end of each of the two rectifier bridges D1-D2, and the other connecting terminal is connected with the other input end of the rectifier bridge D1 and is connected with the other input end of the rectifier bridge D2 through the phase shifter; the output ends of the two rectifier bridges D1-D2 respectively drive a light-emitting diode of an optocoupler to emit light; the light receivers of the two optical couplers U1-U2 are connected in parallel to form a branch circuit, the branch circuit is connected with a resistor R2 in series and then bridged between VCC and ground, and a joint between the branch circuit and the resistor R3 is used as a signal output node DSP-32 of a circuit for rapidly detecting a single-phase alternating current power supply signal. The method is used for solving the problem that the single-phase alternating current power supply can not be quickly and accurately detected when the single-phase alternating current power supply is judged.
Description
Technical Field
The invention relates to the field of power electronics, in particular to a circuit for rapidly detecting a single-phase alternating-current power supply signal.
Background
In power electronic products, a single-phase alternating current power supply is generally used as a control power supply of a system, and supplies power to the control system after AC/DC conversion. Due to the existence of energy storage elements such as an inductor and a capacitor in the AC/DC, the control system can still work for a short time even after the single-phase alternating current power supply is disconnected. However, the power failure of the single-phase alternating-current power supply is a very severe event, which may have serious influence on the system, affect normal production and life, and even damage the system. Therefore, fast and reliable detection of a single-phase ac power loss becomes important.
As shown in FIG. 1, the single-phase AC voltage waveform has an effective value of AC220V, a frequency of 50Hz, a maximum voltage of 311V, a minimum voltage of-311V, and an intermediate voltage of 0V. In the figure, the ordinate is the voltage in V and the abscissa is the time axis in s. The voltage is 0V at 0ms, i.e. sin0 °, 311V at 5ms, i.e. sin90 °, 0V at 10ms, i.e. sin180 °, minus 311V at 15ms, i.e. sin270 °, and 0V at 20 ms. By analogy, a voltage of 0V will appear every 10 ms.
Fig. 2 shows a conventional single-phase ac power signal detection circuit, L, N being a single-phase ac inlet terminal, i.e. live and neutral. When the voltage of the live wire L is higher than the voltage of the zero line N (positive half cycle), namely sin 0-sin 180 degrees, a light emitting diode of the optocoupler U1 emits light, an internal phototriode is conducted, and at the moment, a DSP-32 terminal outputs low level. At this time, the light emitting diode of the optocoupler U2 is in a reverse state, and cannot be turned on to emit light, and the internal phototriode is cut off. When the voltage of the live wire L is lower than the zero line N, namely, sin 180-sin 360 degrees (negative half cycle), a light emitting diode of the optocoupler U2 emits light, an internal phototriode is conducted, and the DSP-32 terminal outputs low level. At this time, the led in U1 is in reverse state and cannot be turned on to emit light. Through the analysis, when the alternating current power supply exists, the DSP-32 terminal outputs low level, after the alternating current power supply is disconnected, the light emitting diodes in the two optocouplers cannot emit light, the two phototriodes are cut off, and the DSP-32 terminal outputs high level. The control system judges according to the high-low level of the DSP-32 terminal, considers that the AC power supply is normal when detecting the low level, and considers that the AC power supply is disconnected when detecting the high level.
However, the method for quickly judging whether the alternating current power supply exists or not is easy to misjudge, because the voltage waveform of the alternating current power supply has 0V voltage and smaller voltage when the positive half cycle and the negative half cycle are alternated, the optical coupler cannot be conducted to emit light, the DSP-32 terminal outputs high level due to the existence of the pull-up resistor R3, so that an output waveform diagram is shown in fig. 3, when the voltage of the live wire L is far higher or far lower than the zero line N, the signal detection circuit outputs low level, when the voltage difference between the live wire L and the zero line N is close to or equal to 0V, the high level is output, and at the moment, the high level signal is obviously unreasonable as a signal for disconnecting the alternating current power supply.
Because the signal detection circuit of the traditional single-phase alternating current power supply signal detection circuit also has high level when the positive half cycle and the negative half cycle are alternated without power failure, a control system cannot correctly judge the power failure condition of the single-phase alternating current power supply. If the control system carries out filtering processing on the signals, the signals are still high level after repeatedly detecting for a period of time when the high level is detected, the signals are considered to be powered down, and power down processing work is started. In this way, although the fault that the power failure is mistakenly reported when the positive and negative half cycles are alternated when the power failure does not exist can be avoided, the fault that the power failure is detected after a period of time lags in the real power failure. If the filtering time is too long, the detection time after the real power failure time lag is prolonged, and if the time is too short, the power failure fault can be mistakenly reported.
In order to solve the problems, the invention adopts a method of adding a symmetrical circuit and a capacitor on the basis of the original circuit, and fundamentally solves the problem that the judgment of the existence of the single-phase alternating current power supply cannot be quickly and accurately detected from the aspects of reliability and rapidity.
Disclosure of Invention
The invention aims to solve the problem that the judgment of the existence of a single-phase alternating current power supply cannot be carried out quickly and accurately.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the circuit for rapidly detecting the single-phase alternating-current power supply signal comprises two wiring terminals, two optocouplers U1-U2, a resistor R2, a phase shifter and two rectifier bridges D1-D2;
the two connecting terminals are respectively used for butting an L line and an N line of a single-phase alternating-current power supply, one connecting terminal is respectively connected with one input end of each of the two rectifier bridges D1-D2, and the other connecting terminal is connected with the other input end of the rectifier bridge D1 and is connected with the other input end of the rectifier bridge D2 through the phase shifter;
the output ends of the two rectifier bridges D1-D2 respectively drive a light-emitting diode of an optical coupler to emit light;
the light receivers of the two optical couplers U1-U2 are connected in parallel to form a branch circuit, the branch circuit is connected with a resistor R2 in series and then bridged between VCC and ground, and a joint between the branch circuit and the resistor R3 is used as a signal output node DSP-32 of a circuit for rapidly detecting a single-phase alternating current power supply signal.
Further, the phase shifter is for shifting the voltage waveform by 90 °.
Further, the phase shifter is specifically a capacitor C1.
Further, the phase shifter is connected to a connection terminal for butting the L line.
Furthermore, resistors are connected in series on the positive buses of the output ends of the two rectifier bridges D1-D2.
Further, the resistance values of the resistors on the positive buses of the output ends of the two rectifier bridges D1-D2 are equal.
Further, VCC is connected to ground after connecting resistance R3, the branch in series in turn.
Furthermore, the light receivers of the two optocouplers U1-U2 are connected in parallel: the 3 feet of the two optical couplers U1-U2 are connected together, and the 4 feet of the two optical couplers U1-U2 are connected together.
According to the signal detection circuit, when a single-phase alternating-current power supply exists, the signal detection circuit outputs high/low levels, and only when the single-phase alternating-current power supply is disconnected, the signal detection circuit outputs opposite levels, so that the output signals of the signal detection circuit can jump rapidly and accurately according to the existence of the single-phase alternating-current power supply, and meanwhile, strong and weak currents are subjected to photoelectric isolation.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like elements throughout the drawings. In the drawings:
FIG. 1 shows a single-phase AC supply voltage waveform;
fig. 2 shows a circuit diagram of a conventional single-phase ac power supply signal detection circuit;
fig. 3 shows an output voltage waveform of a conventional single-phase ac power supply signal detection circuit;
FIG. 4 is a circuit diagram of a circuit for rapidly detecting a single-phase AC power signal in accordance with the present invention;
fig. 5 shows the voltage waveform across the capacitor C1.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The circuit for rapidly detecting the single-phase alternating-current power supply signal is shown in fig. 4 and comprises two wiring terminals, two optocouplers U1-U2, a resistor R2, a phase shifter and two rectifier bridges D1-D2.
The two connecting terminals are respectively used for butting an L line and an N line of a single-phase alternating-current power supply, one connecting terminal is respectively connected with one input end of each of the two rectifier bridges D1-D2, and the other connecting terminal is connected with the other input end of the rectifier bridge D1 and is connected with the other input end of the rectifier bridge D2 through the phase shifter;
the output ends of the two rectifier bridges D1-D2 respectively drive a light-emitting diode of an optocoupler to emit light;
the light receivers of the two optical couplers U1-U2 are connected in parallel to form a branch circuit, the branch circuit is connected with a resistor R2 in series and then bridged between VCC and ground, and a joint between the branch circuit and the resistor R3 is used as a signal output node DSP-32 of a circuit for rapidly detecting a single-phase alternating current power supply signal.
In the scheme, after a single-phase alternating current power supply is added to a wiring terminal, the single-phase alternating current is input into two optocouplers U1-U2 after being rectified by a rectifier bridge, due to the existence of a phase shifter, the output voltage waveforms of the rectifier bridges D1 and D2 are staggered, when the output voltage waveform of the rectifier bridge D1 is close to 0V, the output voltage waveform of the rectifier bridge D2 is not zero, and therefore the low level output by the node DSP-32 is kept. Therefore, the node DSP-32 outputs a low level all the time as long as there is a single-phase ac power, and the node DSP-32 outputs a high level after the ac power is turned off.
As an implementation scheme, the phase shifter is specifically used as a capacitor C1, so that circuit simplification and cost control are achieved.
Further, the capacitor C1 is used to shift the voltage waveform by 90 °, so, as shown in fig. 5, the voltage waveforms at the two ends of the capacitor C1 are staggered by 90 °, when the output voltage waveform of the rectifier bridge D1 is close to 0V, the output voltage waveform of the rectifier bridge D2 is just at the maximum value (311V) or the minimum value (-311V), and at this time, the optical coupler is in the most stable conducting state.
In one embodiment, the capacitor C1 is connected to the terminal for the mating L-line. If the capacitor C1 is connected to the terminal for the N line, a high will still be present when the first positive half cycle of the single phase ac power on transmission ends at approximately 0V, and not thereafter. If the capacitor C1 is connected to the terminal for connecting the L line, the high level generation can be eliminated at the end of the first positive half cycle of the single-phase ac power supply start-up transmission, and a better optimization can be achieved.
Preferably, a resistor R1 is connected in series with the positive bus of the output end of the rectifier bridge D1, and a resistor R3 is connected in series with the positive bus of the output end of the rectifier bridge D2, so as to implement input power protection. The resistance R1 is equal to the resistance R3 to maintain the circuit symmetry.
As an implementation scheme, VCC is used for being sequentially connected with a resistor R3 in series, and the branch circuit is connected to the ground, so that the node DSP-32 is pulled up, and the voltage of the node DSP-32 is ensured to be stable when the optical coupler is not conducted.
The output signal of the detection circuit can be directly judged by the control system, the high level indicates that the alternating current power supply is disconnected, the low level indicates that the alternating current power supply exists, and the control system does not need to carry out filtering or other special treatment, so that the aims of rapidness and accuracy are fulfilled.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (8)
1. A circuit for rapidly detecting a single-phase alternating-current power supply signal is characterized in that:
the circuit comprises two wiring terminals, two optocouplers U1-U2, a resistor R2, a phase shifter and two rectifier bridges D1-D2;
the two connecting terminals are respectively used for butting an L line and an N line of a single-phase alternating-current power supply, one connecting terminal is respectively connected with one input end of each of the two rectifier bridges D1-D2, and the other connecting terminal is connected with the other input end of the rectifier bridge D1 and is connected with the other input end of the rectifier bridge D2 through the phase shifter;
the output ends of the two rectifier bridges D1-D2 respectively drive a light-emitting diode of an optical coupler to emit light;
the light receivers of the two optical couplers U1-U2 are connected in parallel to form a branch circuit, the branch circuit is connected with a resistor R2 in series and then bridged between VCC and ground, and a joint between the branch circuit and the resistor R3 is used as a signal output node DSP-32 of a circuit for rapidly detecting a single-phase alternating current power supply signal.
2. The circuit for rapidly detecting a single-phase alternating current power supply signal as claimed in claim 1, wherein: the phase shifter is for shifting the voltage waveform by 90 °.
3. A circuit for rapidly detecting a single-phase ac power supply signal as claimed in claim 1 or 2, wherein: the phase shifter is in particular a capacitor C1.
4. The circuit for rapidly detecting a single-phase ac power supply signal as claimed in claim 1, wherein: the phase shifter is connected to a terminal for butting an L line.
5. The circuit for rapidly detecting a single-phase alternating current power supply signal as claimed in claim 4, wherein: resistors are connected in series on positive buses of output ends of the two rectifier bridges D1-D2.
6. The circuit for rapidly detecting a single-phase alternating current power supply signal as claimed in claim 5, wherein: the resistance values of the positive buses of the output ends of the two rectifier bridges D1-D2 are equal.
7. The circuit for rapidly detecting a single-phase alternating current power supply signal as claimed in claim 1, wherein: VCC is connected to ground after connecting resistance R3, branch in turn.
8. The circuit for rapidly detecting a single-phase alternating current power supply signal according to claim 1, wherein the light receivers of the two optocouplers U1 to U2 are connected in parallel with each other in a manner that: the 3 pins of the two optical couplers U1-U2 are connected together, and the 4 pins of the two optical couplers U1-U2 are connected together.
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| CN202121245819.6U CN217404498U (en) | 2021-06-04 | 2021-06-04 | Circuit for rapidly detecting single-phase alternating current power supply signal |
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| CN202121245819.6U CN217404498U (en) | 2021-06-04 | 2021-06-04 | Circuit for rapidly detecting single-phase alternating current power supply signal |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113433481A (en) * | 2021-06-04 | 2021-09-24 | 广东福德电子有限公司 | Circuit for rapidly detecting single-phase alternating current power supply signal |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113433481A (en) * | 2021-06-04 | 2021-09-24 | 广东福德电子有限公司 | Circuit for rapidly detecting single-phase alternating current power supply signal |
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