CN101833031A - AC signal zero crossing detection circuit - Google Patents
AC signal zero crossing detection circuit Download PDFInfo
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- CN101833031A CN101833031A CN 201010182029 CN201010182029A CN101833031A CN 101833031 A CN101833031 A CN 101833031A CN 201010182029 CN201010182029 CN 201010182029 CN 201010182029 A CN201010182029 A CN 201010182029A CN 101833031 A CN101833031 A CN 101833031A
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Abstract
The invention provides an AC signal zero crossing detection circuit. The circuit comprises a comparator; the non-inverting input end of the comparator is connected with a ground resistance, and the output end of the comparator is connected with a current-limiting resistance; and a resistance is connected between the non-inverting input end of the comparator and the current-limiting resistance, and more than two filters are serially connected between a signal to be tested and the inverting input end of the comparator. By arranging more than two filters which are serially connected between the signal to be tested and the inverting input end of the comparator, the invention realizes accurately capturing the zero crossing point of an AC signal to ensure that the obtained zero crossing point and the input AC signal to have the same frequency and phase.
Description
Technical field
The present invention relates to a kind of detection technique, relate in particular to a kind of AC signal zero crossing detection circuit; Belong to technical field of automation.
Background technology
Zero passage detection refer to the AC signal waveform from positive half cycle to the negative half period transfer process, to it through the detection of zero-bit.Zero passage detection has vital role in AC system; for example: in the switch designs of AC power equipment; usually switching point can be chosen in the zero crossing of AC signal; can reduce interference like this to power supply; and be not easy phenomenons such as sparking and noise to occur, simultaneously equipment played a protective role.
In the prior art to the zero passage detection of AC signal, common in-phase input end process resistance eutral grounding with comparer, output terminal at comparer connects current-limiting resistance, between the in-phase input end of comparer and output terminal, connect resistance, with the inverting input of the direct input comparator of AC signal to be detected or via the reverse input end of various wave filter input comparators.Owing to contain harmonic wave in the AC signal, therefore, cause the zero cross signal that obtains and the different frequencies of AC signal of input or homophase not easily.
Summary of the invention
The technical problem to be solved in the present invention is: provide a kind of AC signal zero crossing detection circuit, to solve in the prior art owing to containing the zero cross signal that obtains that harmonic wave causes different frequencies of AC signal or the out of phase problem with input in the AC signal.
The invention provides a kind of AC signal zero crossing detection circuit, comprise: a comparer, the in-phase input end of described comparer is connected with a stake resistance, the output terminal of described comparer is connected with a current-limiting resistance, be connected with a resistance between the in-phase input end of described comparer and the described current-limiting resistance, be serially connected with two above wave filters between the inverting input of signal to be detected and described comparer.
Wherein, comprise more than one first bandpass filter and more than one second bandpass filter in described two above wave filters; The described first bandpass filter centre frequency is less than described signal frequency to be detected, and the described second bandpass filter centre frequency is greater than described signal frequency to be detected.
Further, the absolute value sum of described first bandpass filter centre frequency and described signal frequency difference to be detected equates with the absolute value sum of described signal frequency difference to be detected with the described second bandpass filter centre frequency.
AC signal zero crossing detection circuit provided by the invention, by two above wave filters of inverting input serial connection at signal to be detected and comparer, realized accurately catching the zero crossing of AC signal, the AC signal that makes the zero crossing that obtains and input with frequently, homophase.
Description of drawings
In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art, to do one to the accompanying drawing of required use in embodiment or the description of the Prior Art below introduces simply, apparently, accompanying drawing in describing below is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the circuit diagram of an AC signal zero crossing detection circuit embodiment of the present invention;
Fig. 2 is the circuit diagram of another AC signal zero crossing detection circuit of the present invention embodiment;
Fig. 3 is the phase diagram of a sinusoidal ac signal zero passage detection of the present invention embodiment.
Embodiment
For the purpose, technical scheme and the advantage that make the embodiment of the invention clearer, below in conjunction with the accompanying drawing in the embodiment of the invention, technical scheme in the embodiment of the invention is clearly and completely described, obviously, described embodiment is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.
Embodiment one
Fig. 1 is the circuit diagram of an AC signal zero crossing detection circuit embodiment of the present invention, as shown in Figure 1, this circuit arrangement comprises: a comparer U1, the in-phase input end of this comparer U1 is connected with a stake resistance R1, the output terminal of comparer U1 is connected with a current-limiting resistance R3, be connected with a resistance R 2 between the in-phase input end of comparer U1 and the current-limiting resistance R3, be serially connected with two above wave filter F between the inverting input (-) of signal to be detected and comparer U1.
Concrete, form zero cross detection circuit by comparer U1, stake resistance R1, current-limiting resistance R3 and resistance R 2, signal to be detected is an AC signal, owing to contain harmonic wave in the AC signal, therefore, the zero cross signal of very difficult assurance output and AC signal to be detected are with frequency, homophase.
Between the inverting input (-) of signal to be detected and comparer U1, be connected in series plural wave filter F, the inverting input (-) of signal input comparator U1 to be detected before, at first pass through plural wave filter F, the effect of these wave filters F is the harmonic wave in the filtering signal to be detected, and adjusts the phase place of AC signal to be detected.
Owing to contain energy-storage travelling wave tubes such as electric capacity among the wave filter F, this signal that will cause the signal to be detected of input filter F and output filter F is homophase not.Because wave filter F can make the leading or hysteresis of input signal phase place, therefore, between the inverting input (-) of signal to be detected and comparer U1, be connected in series plural wave filter F, realize that at least one wave filter F makes the phase place of signal to be detected leading, at least one wave filter F makes the phase lag of signal to be detected, by selecting the wave filter F of suitable frequency, make in advance to equate with the phase place that lags behind.
Concrete, when two wave filter F of serial connection, first wave filter F can make the leading certain angle of phase place of signal to be detected, second wave filter F can make the phase lag certain angle of signal to be detected, by selecting to be fit to the wave filter F of frequency, make the leading angle of the first wave filter F identical, the angle of lead and lag is cancelled each other, thereby realize output signal and signal homophase to be detected with the angle that second wave filter F lags behind.Because two wave filter F itself have filter action, realize that output signal and signal to be detected are with frequently again.Equally, if first wave filter F makes signal lag certain angle to be detected, second wave filter F makes the leading certain angle of signal to be detected, can realize that equally output signal and signal to be detected are with frequently.
Be understandable that, when being serially connected with three above wave filter F, among these wave filters F, frequency by selective filter, assurance has at least a wave filter F to make the leading certain angle of signal to be detected, other wave filters F makes the same angle of signal lag to be detected, thereby the angle of lead and lag is cancelled each other; Perhaps guarantee to have at least a wave filter F to make the certain angle of signal lag to be detected, other wave filters F makes the leading same angle of signal to be detected.
Wherein, wave filter F can select the wave filter of low-pass filter, Hi-pass filter, bandpass filter or other types.
The AC signal zero crossing detection circuit that present embodiment provides, by being connected in series two above wave filters between signal to be detected and the comparer, thereby the leading certain angle of phase place that assurance has at least a wave filter to make signal to be detected, and have at least a wave filter to make the phase lag certain angle of signal to be detected, thereby the angle of leading angle and hysteresis is cancelled each other, realize accurately catching the zero crossing of AC signal, make the zero crossing that obtains and AC signal to be detected with frequency, homophase.
Embodiment two
Fig. 2 is the circuit diagram of another AC signal zero crossing detection circuit of the present invention embodiment, as shown in Figure 2, this circuit arrangement comprises: a comparer U1, the in-phase input end of this comparer U1 is connected with a stake resistance R1, the output terminal of comparer U1 is connected with a current-limiting resistance R3, be connected with a resistance R 2 between the in-phase input end of comparer U1 and the current-limiting resistance R3, be serially connected with two above wave filters between the inverting input (-) of signal to be detected and comparer U1.
Wherein, comprise more than one first bandpass filter and more than one second bandpass filter in two above wave filters; The first bandpass filter centre frequency is less than signal frequency to be detected, and the second bandpass filter centre frequency is greater than signal frequency to be detected.
The absolute value sum of the first bandpass filter centre frequency and signal frequency difference to be detected equates with the absolute value sum of signal frequency difference to be detected with the second bandpass filter centre frequency.
Concrete, be provided with plural wave filter between the inverting input of signal to be detected and comparer U1, before the inverting input of AC signal input comparator U1 to be detected, at first carry out filtering and phase place adjustment by two above wave filters.
Select more than one first bandpass filter in the present embodiment for use and more than one second bandpass filter treat detection signal and carry out filtering and phase place adjustment.For bandpass filter, centre frequency can make the phase lag of signal to be detected less than the bandpass filter of signal frequency to be detected, and centre frequency can make the phase place of signal to be detected leading greater than the bandpass filter of signal frequency to be detected.According to these characteristics of bandpass filter, the centre frequency that can select first bandpass filter is less than signal frequency to be detected, and the centre frequency of second bandpass filter is greater than the frequency of signal to be detected.When the centre frequency of bandpass filter during greater than signal frequency to be detected, signal to be detected is through after this bandpass filter, its phase place is with leading certain angle, and when bandpass filter centre frequency during less than signal frequency to be detected, signal to be detected is through after this bandpass filter, and its phase place is with the hysteresis certain angle.
Signal to be detected can be earlier by first bandpass filter of centre frequency less than signal frequency to be detected, again by second bandpass filter of centre frequency greater than signal frequency to be detected before the inverting input that enters comparer U1; Also can pass through second bandpass filter earlier, again by first bandpass filter.
If between the inverting input of signal to be detected and comparer U1 one first bandpass filter and one second bandpass filter are only arranged, then the frequency of first bandpass filter of Xuan Zeing and second bandpass filter need meet the following conditions and offset fully with the leading angle of the phase place that guarantees signal to be detected and the angle of hysteresis:
|f0-f1|＝|f2-f0|；
Wherein, f0 is the frequency of signal to be detected, and f1 is the centre frequency of first bandpass filter, and f2 is the centre frequency of second bandpass filter.
If be serially connected with more than one first bandpass filter between the inverting input of signal to be detected and comparer U1 and more than one during second bandpass filter, then the frequency of first bandpass filter of Xuan Zeing and second bandpass filter need meet the following conditions and offset fully with the leading angle of the phase place that guarantees signal to be detected and the angle of hysteresis:
Wherein: n 〉=1, m 〉=1, f1n is the centre frequency of first bandpass filter, f2m is the centre frequency of second bandpass filter.
The situation that is provided with three bandpass filter between the inverting input with signal to be detected shown in Figure 2 and comparer U1 is an example, if the frequency of signal to be detected is f0, the centre frequency of wave filter F1 is f1, and the centre frequency of wave filter F2 is f2, and the centre frequency of wave filter F3 is f3.
Can select F1 and F2 is second bandpass filter: f1＞f0, and f2＞f0, F3 are first bandpass filter: f3＜f0, and satisfies | f1-f0|+|f2-f0|=|f0-f3|;
Wherein,, compare the further leading again certain angle of signal1 from the signal signal2 of F2 output from the leading certain angle of signal signal1 of F1 output, and from the signal signal3 and the signal signal0 homophase to be detected of F3 output.Be that F1 makes leading angle of signal to be detected and F3 make the angle of signal lag to be detected identical with F2.
Can also select: f1＞f0, f2＜f0, f3＜f0, and | f1-f0|=|f0-f2|+|f0-f3|;
Be that F1 makes the leading angle of signal to be detected and F2 and F3 make the angle of signal lag to be detected identical.Below only enumerate two kinds of feasible situations, as long as satisfy
The phase place of leading phase place of signal to be detected and hysteresis is offset fully.
In addition, because behind the AC signal process wave filter, certain decay can appear in its amplitude, through two above wave filters, then serious decay appears in amplitude probably as if signal to be detected, therefore, can guarantee the amplitude of signal to be detected by selecting gain A.
Below provide one more specifically example describe, referring to Fig. 3, the amplitude of the common frequency power network signal signal0 of input is V1, frequency is f0=50Hz; At the input end of common frequency power network signal and the inverting input of comparer two bandpass filter are set, its frequency is respectively f1 and f2, f1=30Hz, f2=70Hz, if do not consider the amplitude attenuation of signal to be detected, the gain of then desirable two bandpass filter can elect 1 as; The output level of comparer U1 is V2, and the size of V2 is by the model decision of comparer.During first bandpass filter of common frequency power network signal signal0 process, the phase lag certain angle is during again through second bandpass filter, the leading certain angle of phase place, because f0-f1=f2-f0, therefore, the square-wave signal of output and the AC signal of input are with frequency, homophase.
In addition, it is the circuit of square wave that the AC signal zero crossing detection circuit that embodiment provides only provides the zero cross signal of output, and for the zero cross signal of other types such as pulse or triangular wave, equally the AC signal zero crossing detection circuit that can adopt present embodiment to provide obtain with frequently, the zero cross signal of homophase.
The AC signal zero crossing detection circuit that present embodiment provides, by being connected in series two above wave filters with the inverting input of comparer at signal to be detected, thereby the leading certain angle of phase place that assurance has at least a wave filter to make signal to be detected, and have at least a wave filter to make the phase lag certain angle of signal to be detected, thereby the angle of leading angle and hysteresis is cancelled each other.Circuit structure is simple, realizes easily, can accurately catch the zero crossing of sinusoidal ac signal, and the sinusoidal ac signal of having realized the zero crossing that obtains and input is with frequency, homophase.
It should be noted that at last: above embodiment only in order to technical scheme of the present invention to be described, is not intended to limit; Although with reference to previous embodiment the present invention is had been described in detail, those of ordinary skill in the art is to be understood that: it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution break away from the spirit and scope of various embodiments of the present invention technical scheme.
Claims (3)
1. AC signal zero crossing detection circuit, comprise: a comparer, the in-phase input end of described comparer is connected with a stake resistance, the output terminal of described comparer is connected with a current-limiting resistance, be connected with a resistance between the in-phase input end of described comparer and the described current-limiting resistance, it is characterized in that: be serially connected with two above wave filters between the inverting input of signal to be detected and described comparer.
2. AC signal zero crossing detection circuit according to claim 1 is characterized in that: comprise more than one first bandpass filter and more than one second bandpass filter in described two above wave filters;
The described first bandpass filter centre frequency is less than described signal frequency to be detected, and the described second bandpass filter centre frequency is greater than described signal frequency to be detected.
3. AC signal zero crossing detection circuit according to claim 2 is characterized in that:
The absolute value sum of described first bandpass filter centre frequency and described signal frequency difference to be detected equates with the absolute value sum of described signal frequency difference to be detected with the described second bandpass filter centre frequency.
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| CN 201010182029 CN101833031A (en) | 2010-05-24 | 2010-05-24 | AC signal zero crossing detection circuit |
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| CN 201010182029 CN101833031A (en) | 2010-05-24 | 2010-05-24 | AC signal zero crossing detection circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102590598A (en) * | 2012-02-15 | 2012-07-18 | 浙江大学 | Method for predicting zero crossing point of ultrasonic signal based on multi-threshold comparison |
| CN105842526A (en) * | 2012-05-19 | 2016-08-10 | 快捷半导体(苏州)有限公司 | Zero-current detection circuit and method, and voltage conversion circuit |
| CN106093564A (en) * | 2016-07-27 | 2016-11-09 | 深圳市康必达控制技术有限公司 | A kind of intelligent electric energy meter based on cloud service |
| CN109917177A (en) * | 2019-04-12 | 2019-06-21 | 国网江苏省电力有限公司宿迁供电分公司 | A kind of jamproof zero cross detection circuit and detection method |
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| DE3723263A1 (en) * | 1986-08-20 | 1988-02-25 | Elin Union Ag | Device for detecting the zero crossings |
| DE4328630C2 (en) * | 1993-08-20 | 1995-06-29 | Aeg Westinghouse Transport | Method for detecting the zero crossing of the fundamental wave of periodic AC voltages subject to frequency fluctuations and arrangement for carrying out the method |
| JPH0989946A (en) * | 1995-09-20 | 1997-04-04 | Nippon Avionics Co Ltd | Detector for a.c. phase and zero cross point |
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2010
- 2010-05-24 CN CN 201010182029 patent/CN101833031A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3723263A1 (en) * | 1986-08-20 | 1988-02-25 | Elin Union Ag | Device for detecting the zero crossings |
| DE4328630C2 (en) * | 1993-08-20 | 1995-06-29 | Aeg Westinghouse Transport | Method for detecting the zero crossing of the fundamental wave of periodic AC voltages subject to frequency fluctuations and arrangement for carrying out the method |
| JPH0989946A (en) * | 1995-09-20 | 1997-04-04 | Nippon Avionics Co Ltd | Detector for a.c. phase and zero cross point |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102590598A (en) * | 2012-02-15 | 2012-07-18 | 浙江大学 | Method for predicting zero crossing point of ultrasonic signal based on multi-threshold comparison |
| CN105842526A (en) * | 2012-05-19 | 2016-08-10 | 快捷半导体(苏州)有限公司 | Zero-current detection circuit and method, and voltage conversion circuit |
| CN105842526B (en) * | 2012-05-19 | 2019-05-24 | 快捷半导体(苏州)有限公司 | A kind of zero current detecting circuit and method and voltage conversion circuit |
| CN106093564A (en) * | 2016-07-27 | 2016-11-09 | 深圳市康必达控制技术有限公司 | A kind of intelligent electric energy meter based on cloud service |
| CN106093564B (en) * | 2016-07-27 | 2019-04-02 | 深圳市康必达控制技术有限公司 | A kind of intelligent electric energy meter based on cloud service |
| CN109917177A (en) * | 2019-04-12 | 2019-06-21 | 国网江苏省电力有限公司宿迁供电分公司 | A kind of jamproof zero cross detection circuit and detection method |
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Application publication date: 20100915 |