CN105044455B

CN105044455B - The frequency of AC signal and the measuring method of phase

Info

Publication number: CN105044455B
Application number: CN201510405191.4A
Authority: CN
Inventors: 俞建定; 王青; 文化锋
Original assignee: Ningbo University
Current assignee: Ningbo University
Priority date: 2015-07-09
Filing date: 2015-07-09
Publication date: 2017-11-24
Anticipated expiration: 2035-07-09
Also published as: CN105044455A

Abstract

The invention discloses a kind of frequency of AC signal and the measuring method of phase, its AC signal given first crosses the frequency measured during the 1st zero point and the phase of determination；Then time during the excessive preceding zero point of AC signal is read；When then by judging the excessive preceding zero point of AC signal and excessively previous zero point when between period in frequency whether determine whether current zero point is interference signal in the reasonable scope；When current zero point is non-interference signal, further according to the time and AC signal currently read excessively previous zero point when the frequency that measures, calculate frequency during the excessive preceding zero point of AC signal, and according to the time and AC signal currently read excessively previous zero point when the frequency that measures determine AC signal excessive preceding zero point when phase；Repeat in real time obtain AC signal excessively each zero point when frequency and phase；Advantage is greatly or in the case of wave distortion, can accurately still to measure frequency even in power network interference, and accurately determines phase, good in anti-interference performance.

Description

The frequency of AC signal and the measuring method of phase

Technical field

The present invention relates to a kind of alternating current signal detection technology, the measurement side of frequency and phase more particularly, to AC signal Method.

Background technology

In many control systems, it is often necessary to power network or other AC signals are detected, and when detecting AC signal Need the zero point of Measuring Alternating Current Signal and the frequency of AC signal and phase.

At present, the method for Measuring Alternating Current Signal frequency has the counting of the chronometry and Timing measurement signal number of measurement period Method.The fixed frequency of general AC signal is 50HZ or 60HZ, and in actual use, frequency is not necessarily strict 50HZ Or 60HZ, certain deviation be present, simultaneously because electronic equipment is used in conjunction with, the waveform of power network can deform or severe jamming, In this case, the measurement result of the method for above-mentioned Measuring Alternating Current Signal frequency can be inaccurate.

At present, the method for Measuring Alternating Current Signal phase has the method that zero crossing timing judges and surveys the side of voltage calculating phase Method.Both approaches can accurately obtain the phase of AC signal, but first method is needed by timer, second Method is needed by a/d converter；In addition, two methods can cause phase measurement because the interference of signal or the inaccuracy of frequency Inaccuracy.

The content of the invention

The technical problems to be solved by the invention are to provide a kind of frequency of AC signal and the measuring method of phase, its energy Enough frequencies and phase for measuring AC signal exactly, and measurement cost is low.

Technical scheme is used by the present invention solves above-mentioned technical problem：A kind of survey of the frequency and phase of AC signal Amount method, it is characterised in that comprise the following steps：

1. make F₁Represent that AC signal crosses the frequency measured during the 1st zero point, and make F₁=F；Make P₁Represent AC signal mistake The phase determined during the 1st zero point, and make P₁=0 degree；Wherein, F represents the estimation frequency of AC signal, and unit is HZ, F's Value is estimated to obtain according to the application scenario of AC signal；

2. assuming that current AC signal crosses i-th of zero point, then time when AC signal crosses i-th of zero point is read, is designated as t_i, unit s, wherein, i initial value is 2, t_iValue for AC signal cross the i-th -1 zero point terminate to cross i-th of zero point knot A period of time of beam；

3. judgeWhether it is more than or equal to F-F × 10% and is less than or equal to F+F × 10%, if it is, thinks i-th Individual zero point is non-interference signal, then performs step 4.；Otherwise it is assumed that i-th of zero point is interference signal, step is then performed ⑤；

4. calculating AC signal crosses the frequency measured during i-th of zero point, F is designated as_i, and unit is HZ, Wherein, F_i-1Represent that AC signal crosses the frequency measured during the i-th -1 zero point, and unit is HZ, f_iRepresent AC signal cross i-th- The frequency in period between when during 1 zero point and crossing i-th of zero point, and unit is HZ,It is then determined that exchange letter Phase during number i-th of zero point of mistake, is designated as P_i, unit is degree,Step is performed again 5.；

5. making i=i+1, it is then back to step and 2. continues executing with, obtains frequency when AC signal crosses i-th of zero point in real time And phase, until AC signal is disposed, wherein, "=" in i=i+1 is assignment.

Compared with prior art, the advantage of the invention is that：

1) AC signal crosses the estimation frequency that the frequency measured during the 1st zero point is AC signal, and is calculating exchange letter During the frequency measured number later during continuous zero point, during preceding zero point excessive according to AC signal and excessively previous zero point when between time Frequency and AC signal in section excessively previous zero point when the frequency that obtains, to calculate what is obtained during the excessive preceding zero point of AC signal Frequency, therefore time of measuring is longer, the frequency of the AC signal measured is more accurate.

2) it is determined that after frequency during AC signal zero crossing point, then phase when determining AC signal zero crossing point, according to friendship The frequency that is measured when time and AC signal during the stream excessive preceding zero point of signal excessive preceding zero point determines that AC signal is excessively current Phase during zero point, because the frequency measured during AC signal zero crossing point is more accurate, therefore it is effectively improved the survey of phase Measure accuracy.

3) remaining zero point of the inventive method to AC signal in addition to the 1st zero point, first passes through and judges that AC signal is excessive During preceding zero point and excessively previous zero point when between period in frequency whether in the reasonable scope, to determine that current zero point is No is interference signal, that is, can be good at determining to disturb unreasonable position, accordingly even when being disturbed in power network big or wave distortion In the case of, frequency can accurately be still measured, and phase is determined, good in anti-interference performance.

Brief description of the drawings

Fig. 1 is the implementation process block diagram of the inventive method；

Fig. 2 is the waveform diagram of an AC signal.

Embodiment

The present invention is described in further detail below in conjunction with accompanying drawing embodiment.

A kind of frequency of AC signal proposed by the present invention and the measuring method of phase, it realizes FB(flow block) such as Fig. 1 institutes Show, it comprises the following steps：

1. make F₁Represent that AC signal crosses the frequency measured during the 1st zero point, and make F₁=F；Make P₁Represent AC signal mistake The phase determined during the 1st zero point, and make P₁=0 degree；Wherein, F represents the estimation frequency of AC signal, and unit is HZ, F's Value is estimated to obtain according to the application scenario of AC signal, as AC signal is applied to power network, then can make F=50HZ or F=60HZ.

2. assuming that current AC signal crosses i-th of zero point, then time when AC signal crosses i-th of zero point is read, is designated as t_i, unit s, wherein, i initial value is 2, t_iValue for AC signal cross the i-th -1 zero point terminate to cross i-th of zero point knot A period of time of beam.

3. judgeWhether it is more than or equal to F-F × 10% and is less than or equal to F+F × 10%, if it is, thinks i-th Individual zero point is non-interference signal, then performs step 4.；Otherwise it is assumed that i-th of zero point is interference signal, ignore i-th of zero point, Frequency and phase are not obtained when i.e. AC signal crosses i-th of zero point, then performs step 5..

4. calculating AC signal crosses the frequency measured during i-th of zero point, F is designated as_i, and unit is HZ,Wherein, F_i-1Represent that AC signal crosses the frequency measured during the i-th -1 zero point, and unit is HZ, f_i The frequency in period between when representing when AC signal crosses the i-th -1 zero point and cross i-th of zero point, and unit is HZ,Phase when then determining that AC signal crosses i-th of zero point by theoretical calculation, is designated as P_i, unit is degree,Step is performed again 5..

To further illustrate the feasibility and validity of the inventive method, tested.

Fig. 2 gives the oscillogram of an AC signal, and the excessively each zero point of AC signal is obtained using the inventive method When the frequency that the measures and phase determined.AC signal crosses the frequency F measured during the 1st zero point₁=F, AC signal cross the 1st The phase P determined during zero point₁=0 degree；When AC signal crosses the 2nd zero point, time when AC signal crosses the 2nd zero point is read For t₂, andMore than or equal to F-F × 10% and it is less than or equal to F+F × 10%, it is thus determined that the 2nd zero point is useful signal Rather than interference signal, pass throughCalculate AC signal and cross the frequency F measured during the 2nd zero point₂, and lead to CrossDetermine phase P when AC signal crosses the 2nd zero point₂；When AC signal crosses the 3rd zero point, read Time when AC signal crosses the 3rd zero point is t₃, andMore than or equal to F-F × 10% and it is less than or equal to F+F × 10%, It is thus determined that the 3rd zero point is useful signal rather than interference signal, pass throughCalculate AC signal mistake The frequency F measured during the 3rd zero point₃, and pass throughDetermine phase when AC signal crosses the 3rd zero point P₃；When AC signal crosses the 4th zero point, the time read when AC signal crosses the 4th zero point is t₄, andIt is not more than or is waiting In F-F × 10% and less than or equal to F+F × 10% in the range of this, it is thus determined that the 4th zero point is interference signal, ignore the 4 zero points；Said process is repeated, determines that the 5th zero point, the 6th zero point and the 7th zero point are useful signal.

Claims

1. a kind of frequency of AC signal and the measuring method of phase, it is characterised in that comprise the following steps：

1. make F₁Represent that AC signal crosses the frequency measured during the 1st zero point, and make F₁=F；Make P₁Represent that AC signal crosses the 1st The phase determined during individual zero point, and make P₁=0 degree；Wherein, F represents the estimation frequency of AC signal, and unit is HZ, F value Estimate to obtain according to the application scenario of AC signal；

2. assuming that current AC signal crosses i-th of zero point, then time when AC signal crosses i-th of zero point is read, is designated as t_i, it is single Position is s, wherein, i initial value is 2, t_iValue cross the i-th -1 zero point for AC signal and terminate to crossing i-th zero point to terminate For a period of time；

3. judgeWhether it is more than or equal to F-F × 10% and is less than or equal to F+F × 10%, if it is, thinks i-th zero Point is non-interference signal, then performs step 4.；Otherwise it is assumed that i-th of zero point is interference signal, then step is performed 5.；

5. making i=i+1, it is then back to step and 2. continues executing with, obtains frequency and phase when AC signal crosses i-th of zero point in real time Position, until AC signal is disposed, wherein, "=" in i=i+1 is assignment.