CN102095937B - Method for quickly measuring instantaneous phase of alternating current electrical signal - Google Patents

Abstract

The invention provides a method for quickly measuring an instantaneous phase of an alternating current electrical signal, which is applicable to the measurement of the instantaneous phase of a low-frequency signal. The method comprises the following steps of: pre-processing a sampling value of the alternating current electrical signal; directly calculating zero crossing point time when the alternating current electrical signals in previous cyclic waves of the alternating current electrical signal are changed from low to high; calculating the cycle of the alternating current electrical signal according to the zero crossing point; forecasting the cycle of the current cyclic waves; and finally calculating the instantaneous phase of the alternating current electrical signal according to the zero crossing point time, the forecast cycle of the alternating current electrical signal and the current time. Compared with the traditional zero crossing method, the method has the advantages that the alternating current electrical signal is not needed to be converted into a square wave, and the disadvantage of low interference resistance of the traditional zero crossing point detection is overcome, so the method is particularly suitable for instantaneous phase measurement of the alternating current electrical signal; moreover, the system is convenient to detect and the hardware expense is low; meanwhile, the method is implemented easily and rationally, and the data is accurate and reliable; and aspects such as measurement precision, interference resistance and the like are improved.

Description

A kind of method of Quick Measurement instantaneous phase of alternating current electrical signal

Technical field

The present invention relates to a kind of method of Quick Measurement instantaneous phase of alternating current electrical signal, this invention can be used for the new energy fields such as wind-power electricity generation, solar electrical energy generation.

Background technology

Usually need to measure the instantaneous phase of ac signal in daily life, production run, the instantaneous phase of measurement is more accurate, and the effect of application is often better.In existing method for measuring instantaneous phase, great majority adopt traditional zero friendship method to measure the instantaneous phase of a certain road signal, and this algorithm is easy to realize, but the impact that is interfered easily, so that the precision of measuring is lower.What industry needed is the software method for measuring instantaneous phase that a kind of operand is little and have certain measuring accuracy.

Summary of the invention

Technical matters to be solved by this invention is not accurate enough for the instantaneous phase measuring accuracy of ac signal in the prior art, a kind of method of Quick Measurement instantaneous phase of alternating current electrical signal has been proposed, traditional zero friendship method of comparing obtains certain raising at aspects such as the precision of measuring, anti-interferences.

The present invention adopts following technical scheme for addressing the above problem:

A kind of method of Quick Measurement instantaneous phase of alternating current electrical signal may further comprise the steps:

Step 1), ac signal is sampled, obtain the sampled value of ac signal; Select n sampled point of combination in any near zero point when tested electric signals some changes from low to high;

Step 2), the sampling time of supposing each sampled point is t _i, sampled value is y _i, then the mean value M of the sampled value of n sampled point and average sample time of origin T are expressed as:

$M_j=\frac{\underset{1}{\overset{n}{\mathrm{\Σ}}}{y}_i}{n},T_j=\frac{\underset{1}{\overset{n}{\mathrm{\Σ}}}{t}_i}{n};$

In the following formula, n 〉=1, n, i, j are natural number, then (M _j, T _j) virtual point of expression;

Step 3), the process, electric signal effective value or the peak value that change from low to high at the ac signal of near zero-crossing point according to tested electric signals, and step 2) the mean value M of sampled value of a described n sampled point _j, obtain a mistiming T ' by the mode of calculating _j, described mistiming T ' _jRepresent under the pure sinusoid signal from virtual point (M _j, T _j) nearest zero crossing and the mistiming between this virtual point; Then corresponding zero crossing time representation is: T _Zj=T _j+ T ' _j

With near approximate straight line, then the zero crossing time T regarded as of the sinusoidal signal zero point _ZjComputing method as follows: $\begin{array}{c}{T}_{\mathrm{zj}}=T_j+T_j^{\′}{\≈T}_j-\frac{M_j}{U_{\mathrm{EMS}}\×\sqrt{2}\×2\×\mathrm{\π}{\×f}_c}=T_j-\frac{M_j\×T_c}{U_{\mathrm{EMS}}\×\sqrt{2}\×2\×\mathrm{\π}}\\ T_{\mathrm{zj}}=T_j+T_j^{\′}\≈T_j-\frac{M_j}{U_{\mathrm{MAX}}\×2\×\mathrm{\π}\×f_c}=T_j-\frac{M_j{\×T}_c}{U_{\mathrm{MAX}}\×2\×\mathrm{\π}}\end{array},$

F wherein _cThe ac voltage standard frequency, T _cThe ac voltage standard cycle, U _MAXThe ac signal maximal value, U _EMSBe the ac signal effective value, the condition that following formula is set up is

Perhaps

Value close to 0;

Step 4), near other zero point that changes from low to high of the sampled value of electric signal, select successively n sampled point of combination in any, repeating step 2) and step 3) obtain several zero crossings time, according to these several zero crossing times, calculate the cycle of tested electric signals;

Step 5), according to step 4) ac signal cycle of calculating, predict cycle of current cycle;

Step 6), time, the step 5 of the zero crossing that calculates when changing from low to high according to previous period ac signal) cycle and current time of current cycle of prediction, calculate current instantaneous phase.

Further, in the method for aforesaid Quick Measurement instantaneous phase of alternating current electrical signal, step 1) described electric signal is sampled is constant duration sampling or not constant duration sampling.

Further, in the method for aforesaid Quick Measurement instantaneous phase of alternating current electrical signal, step 1) described being sampled as sampled to the complete cycle ripple of electric signal.

The concrete steps in the calculating tested electric signals cycle further, in the method for aforesaid Quick Measurement instantaneous phase of alternating current electrical signal, step 4) are as follows: repeating step 2), step 3) obtain several zero crossing time T _Z1, T _Z2, T _Z3... T _Zj, T _Zj+1, T _Zj+2... T _Zn..., the cycle of tested ac signal: T then _Pj=T _Zj+1-T _Zj, the cycle of the signal that therefore obtains is followed successively by T _P1, T _P2, T _P3, T _P4... T _Pk-1, T _Pk..., k is natural number.

Further, in the method for aforesaid Quick Measurement instantaneous phase of alternating current electrical signal, step 5) ac period that calculated of described basis predicts that the step of current cycle period is as follows:

The cycle of a) establishing by several cycles before the ac signal that calculates is followed successively by T _Pk-3, T _Pk-2, T _Pk-1, T _Pk, the cycle of current several cycles does not exist or when can not get, makes it equal the ac voltage standard cycle;

B) periodic table of the current cycle of prediction is shown:

T _Pt=K ₁* T _Pk+ K ₂* T _Pk-1+ K ₃* T _Pk-2+ K ₄* T _Pk-3K in the formula ₁, K ₂, K ₃, K ₄Be arbitrary constant, but the K that must satisfy condition ₁+ K ₂+ K ₃+ K ₄=1.

Further, in the method for aforesaid Quick Measurement instantaneous phase of alternating current electrical signal, step 6) concrete steps are as follows: the time of establishing ac signal zero crossing from low to high is T _z, the current time is T _Ct, by step 5) and predict that the cycle of the current cycle of ac signal that obtains is T _Pt, then current instantaneous phase is expressed as: Or be expressed as:

The result who calculates is respectively the phase value that represents with the number of degrees or radian.

Further, in the method for aforesaid Quick Measurement instantaneous phase of alternating current electrical signal, be offset ac voltage standard during the cycle in tested alternating current actual cycle, step 3) the middle predetermined period T that adopts current cycle _c' replacement ac voltage standard cycle T _cCalculate, obtain T _c' method as follows:

The cycle of a) establishing by several cycles before the ac signal that calculates is followed successively by T _Pk-3, T _Pk-2, T _Pk-1, T _Pk, the cycle of current several cycles does not exist or when can not get, makes it equal the ac voltage standard cycle;

B) periodic table of the current cycle of prediction is shown:

T _c'=K ₁* T _Pk+ K ₂* T _Pk-1+ K ₃* T _Pk-2+ K ₄* T _Pk-3K wherein ₁, K ₂, K ₃, K ₄Be arbitrary constant, but the K that must satisfy condition ₁+ K ₂+ K ₃+ K ₄=1.

The present invention adopts above technical scheme to have following beneficial effect:

1) traditional two opposite continuity points of zero friendship method symbolization are determined zero crossing, although the algorithm clear physics conception is subjected to the interference of harmonic wave, measuring error etc. easily, measuring accuracy is low.Only have an accurate location zero crossing, just can calculate accurate frequency and instantaneous phase.Along with the raising of acquisition speed, can near zero point, select arbitrarily several sampled points.Obtained the particular location of zero crossing through calculating by several sampled points of choosing.Determined to accurately calculate the instantaneous phase of ac signal after the zero crossing of signal.Traditional zero friendship method of comparing, operand greatly reduces, and the precision of measurement, anti-interference do not reduce yet.

2) sampling involved in the present invention can be the constant duration sampling, also can be not constant duration sampling, if the constant duration sampling, then operand can further reduce through optimizing.

3) the method can be chosen several sampled points and participate in calculating when calculating, and this can reduce the stochastic error of system to a certain extent; The another one advantage of the method is that the calculated amount of algorithm and the number of the sampled point of choosing only present linear dependence, and when the sampling number of choosing increased, the precision of computing can greatly improve but operand can not present exponential increase.

4) the present invention is straight line with sine curve fitting near sinusoidal zero point, has certain error of calculation, but at the M of virtual point _jWhen very approaching zero, error almost can be ignored.

Description of drawings:

Fig. 1 carries out constant duration sampling and the synoptic diagram of 8 sampled points obtaining near zero point.

Fig. 2 is the synoptic diagram that is calculated the signal zero crossing that obtains by 4 negative level sampled points.

Fig. 3 is the synoptic diagram that is calculated the signal zero crossing that obtains by 3 negative levels and 1 positive level sampled point.

Fig. 4 is the synoptic diagram that is calculated the signal zero crossing that obtains by 2 positive levels and 2 negative level sampled points.

Fig. 5 is under the sampling of constant duration not situation, is calculated the synoptic diagram of the signal zero crossing that obtains by 1 negative level and 3 positive level sampled points.

Fig. 6 is the synoptic diagram that calculates ac period.

Fig. 7 is the synoptic diagram that calculates some sampled point instantaneous phases.

Embodiment

Below in conjunction with accompanying drawing technical scheme of the present invention is elaborated:

Essence of the present invention is that several sampled points are carried out pre-service by the zero crossing that directly calculates signal; Calculated afterwards cycle and the instantaneous phase of signal by a series of zero crossings.The sampled point of choosing is too much unsuitable, if the sampled point of choosing is more, calculating will be more complex; The sampled point of choosing is also unsuitable very few, if the sampled point of choosing is less, and the impact that is interfered easily.So the user can choose rational sampled point combination as required and number is calculated.

For obtaining comparatively accurate measurement result, the Choice of the sampled point of suggestion is: the quantity of the quantity of positive sampled point and the sampled point of bearing equates or about equally, the number of sampled point then can be determined according to concrete actual conditions.

Principle of the present invention describes by the instantaneous phase of measuring some sampled points.Raising along with sample rate, the sampling number of the generation in a cycle is also more and more, when sampling number is abundant, can select several sampled points near the zero point when ac signal changes from low to high, calculate mean value M and the average sample time of origin T of several sampled points, then obtain T ' according to characteristics and the mean value M calculating of current demand signal, come the zero crossing of approximate representation signal by T+T ', thereby calculate the cycle of signal; Further can calculate instantaneous phase sometime.All adopt four sampled points to calculate zero crossing in the follow-up embodiment, can suitably increase or reduce as required the number of sampled point in the practical application.Specific implementation process of the present invention is as follows:

1. tested electric signals is sampled, described here be sampled as the sampling that the complete cycle ripple is carried out.Can be the constant duration sampling, also can be not constant duration sampling.

2. near each zero point of signal, select several sampled points of combination in any.Zero point when referring to ac signal here said zero point and changing from low to high.The sampled value of the sampled point of selecting can just all be; Also can be all to be negative; Also can select as required several sampled values for just, several sampled values are negative sampled point.S0 on Fig. 1, S1, S2, S3, S4, S5, S6, S7 carry out constant duration sampling and 8 sampled points obtaining near zero point.Can in above-mentioned 8 points (but being not limited only to this 8 points), select several sampled points.Be to obtain comparatively accurate measurement result, the Choice of the sampled point of suggestion is: the quantity of the quantity of positive sampled point and negative sampled point equates or about equally.

3. the step of calculating the mean value M of several sampled points and average sample time of origin T is as follows:

1) selects several sampled points of combination in any near the zero point when the changing from low to high of ac signal;

2) suppose that the sampling number of choosing is n, the sampling time of each sampled point is t _i, sampled value is y _i, then the mean value M of n sampled point and average sample time of origin T can be expressed as:

$M_j=\frac{\underset{1}{\overset{n}{\mathrm{\Σ}}}{y}_i}{n},T_j=\frac{\underset{1}{\overset{n}{\mathrm{\Σ}}}{t}_i}{n};$

In the following formula, n 〉=1, i, j are natural number, then (M _j, T _j) can regard a virtual point as;

The process that obtains zero crossing is as follows: obtain (M _j, T _j) after, by the characteristics of current demand signal, the effective value of signal (perhaps peak value) and M _jObtain T ' by direct calculating _j, T ' _jPhysical significance be under the pure sinusoid signal, from virtual point (M _j, T _j) nearest zero crossing and the mistiming between this virtual point.Because in step 2) in the sampled point chosen choose T ' then near the zero point when the changing from low to high of ac signal _jCan be expressed as:

$T_j^{\′}=-1\×\frac{\arcsin \frac{M_j}{U_{\mathrm{EMS}}\×\sqrt{2}}}{2\×\mathrm{\π}\×f}=-1\×\frac{\arcsin \frac{M_j}{U_{\mathrm{MAX}}}}{2\×\mathrm{\π}\×f}$

When Hour, T ' _jBut approximate representation is:

$T_j^{\′}=-1\×\frac{\arcsin \frac{M_j}{U_{\mathrm{EMS}}\×\sqrt{2}}}{2\×\mathrm{\π}\×f}\≈-1\×\frac{M_j}{U_{\mathrm{EMS}}\×\sqrt{2}\×2\×\mathrm{\π}\×f_c}=-1\×\frac{M_j\×T_c}{U_{\mathrm{EMS}}\×\sqrt{2}\×2\×\mathrm{\π}}$

$T_j^{\′}=-1\×\frac{\arcsin \frac{M_j}{U_{\mathrm{MAX}}}}{2\×\mathrm{\π}\×f}\≈-1\×\frac{M_j}{U_{\mathrm{MAX}}\×2\×\mathrm{\π}\×f_c}=-1\×\frac{M_j\×T_c}{U_{\mathrm{MAX}}\×2\×\mathrm{\π}}$ ；

In above-mentioned several formula, f _cThe ac voltage standard frequency, T _cThe ac voltage standard cycle, U _MAXThe ac signal maximal value, U _EMSIt is the ac signal effective value.The establishment condition of above-mentioned several formula is

Perhaps

As far as possible little.Under normal conditions,

Less, the effect of then using is better, requirement in the follow-up application

Scope just carry out the calculating of zero crossing in [0.1,0.1].

After the calculating, then the corresponding zero crossing time can be expressed as: T _Zj=T _j+ T ' _j

4. point (the M at the hollow triangle place among Fig. 2 ₀, T ₀) be by the sampled point S0 among Fig. 1, S1, S2, S3 calculate the virtual point of rear acquisition, and the point at open circles place is the zero crossing that obtains afterwards as calculated; Point (the M at the hollow triangle place among Fig. 3 ₁, T ₁) be by the sampled point S1 among Fig. 1, S2, S3, S4 calculate the virtual point of rear acquisition, and the point at open circles place is the zero crossing that obtains afterwards as calculated; Point (the M at the hollow triangle place among Fig. 3 ₂, T ₂) be by the sampled point S2 among Fig. 1, S3, S4, S5 calculate the virtual point of rear acquisition, and the point at open circles place is the zero crossing that obtains afterwards as calculated; Sampling in the example of Fig. 2, Fig. 3, Fig. 4 is the constant duration sampling.Fig. 5 is the result schematic diagram that does not obtain under the constant duration sampling situation, the point (M at hollow triangle place ₃, T ₃) be by the sampled point S0 among the figure, S1, S2, S3 calculate the virtual point of rear acquisition, and the point at open circles place is the zero crossing that obtains afterwards as calculated.

5. obtain several zero crossings and can carry out the calculating of signal period after the time, ac signal among Fig. 6 has carried out calculating for four times (near 2 positive levels and 2 the negative level sampled points zero point are adopted in each calculating) near zero point (zero crossing when signal changes from low to high), obtain the virtual point at four hollow triangle places, obtained four zero crossing: T at open circles place after directly being calculated by four virtual point ₁, T ₂, T ₃, T ₄Because the cycle of tested ac signal can be expressed as: T _Pj=T _J+1-T _j, so among Fig. 6 the signal period can be expressed as: T _P3=T ₄-T ₃, T _P2=T ₃-T ₂, T _P1=T ₂-T ₁

6. a prerequisite measuring the alternating current instantaneous phase is the cycle that obtains current cycle, but before current cycle does not finish, the cycle of current cycle also can't directly obtain, rapid variation generally can not occur in the cycle (frequency) of considering ac signal, and the present invention has adopted a formula to predict the cycle T of current cycle _PtThis formula can be expressed as: T _Pt=K ₁* T _Pk+ K ₂* T _Pk-1+ K ₃* T _Pk-2+ K ₄* T _Pk-3Make K in the follow-up calculating ₁=2, K ₂=-1, K ₃=K ₄=0, i.e. T _Pt=2 * T _Pk-T _Pk-1

7. the calculating of instantaneous phase can be referring to Fig. 7, calculating be the instantaneous phase of sampled point S among Fig. 7, the sampling time of establishing sampled point S among Fig. 7 is T _Ct, the time of the upper ac signal zero crossing from low to high that calculates is T _z, then the instantaneous phase of sampled point S can be expressed as

T wherein _PtIt is the cycle of predicting the current cycle of ac signal that obtains.The result who calculates is the phase value that represents with the number of degrees.The instantaneous phase of other sampled points among Fig. 7 also can adopt similar method to obtain.The computing method of the phase place of an interior random time point of cycle are the same.

8. the present invention adopts the ac voltage standard cycle T _cCalculate zero crossing T _Zj, when little in the tested alternating current actual cycle skew ac voltage standard cycle, can obtain comparatively accurately measurement result.When the tested alternating current actual cycle skew ac voltage standard cycle has to a certain degree, if still adopt the ac voltage standard cycle T _cCalculate zero crossing T _Zj, then may produce the larger error of calculation, can adopt predetermined period T of current cycle this moment _c' replacement ac voltage standard cycle T _cCalculate.Obtain T _c' method as follows: the cycle of establishing by several cycles before the ac signal that calculates is followed successively by T _Pk-3, T _Pk-2, T _Pk-1, T _Pk(when the cycle of cycle does not calculate in front, can make partly or completely T _Pk-3, T _Pk-2, T _Pk-1, T _PkEqual the ac voltage standard cycle); Then the cycle of the current cycle of prediction can be expressed as: T _c'=K ₁* T _Pk+ K ₂* T _Pk-1+ K ₃* T _Pk-2+ K ₄* T _Pk-3K in the formula ₁, K ₂, K ₃, K ₄Can be arbitrary constant, but the K that must satisfy condition ₁+ K ₂+ K ₃+ K ₄=1.As adopt predetermined period T of current cycle _c' calculate zero crossing T _Zj, can obtain more accurately result.In above-mentioned experiment, make K ₁=1, K ₂=K ₃=K ₄=0, T then _c'=T _Pk, think that namely the cycle of current cycle is identical with the cycle of a upper cycle.

Preferred version is the described constant duration sampling that is sampled as.

In sum, the method of a kind of Quick Measurement instantaneous phase of alternating current electrical signal involved in the present invention, do not need to convert ac signal to square wave, overcome the shortcoming that traditional zero crossing detects poor anti jamming capability, the instantaneous phase that is particularly suitable for ac signal is measured, system is easy to detect, and hardware spending is little; The antijamming capability of system is stronger; Implement advantages of simple, data accurately, reliably; More widely application prospect is arranged.Certainly, the present invention also can be applied to the instantaneous phase measurement of Low Frequency Sine Signals.

Claims (7)

1. the method for a Quick Measurement instantaneous phase of alternating current electrical signal is characterized in that: may further comprise the steps:

Step 1) is sampled to ac signal, obtains the sampled value of ac signal; Select n sampled point of combination in any near zero point when tested electric signals some changes from low to high;

Step 2), the sampling time of supposing each sampled point is t _i, sampled value is y _i, the mean value M of the sampled value of n sampled point then _jWith average sample time of origin T _jBe expressed as:

$M_j=\frac{\underset{1}{\overset{n}{\mathrm{\Σ}}}{y}_i}{n},$ $T_j=\frac{\underset{1}{\overset{n}{\mathrm{\Σ}}}{t}_i}{n};$

In the following formula, n 〉=1, n, i, j are natural number, then (M _j, T _j) virtual point of expression;

Step 3), the process, electric signal effective value or the peak value that change from low to high at the ac signal of near zero-crossing point according to tested electric signals, and step 2) the mean value M of sampled value of a described n sampled point _j, obtain a mistiming T ' by the mode of calculating _j, described mistiming T ' _jRepresent under the pure sinusoid signal from virtual point (M _j, T _j) nearest zero crossing and the mistiming between this virtual point; Then corresponding zero crossing time representation is: T _Zj=T _j+ T ' _j

With near approximate straight line, then the zero crossing time T regarded as of the sinusoidal signal zero point _ZjComputing method as follows:

$T_{\mathrm{zj}}=T_j+T_j^{\′}\≈T_j-\frac{M_j}{U_{\mathrm{EMS}}\×\sqrt{2}\×2\×\mathrm{\π}\×f_c}=T_j-\frac{M_j\×T_c}{U_{\mathrm{EMS}}\×\sqrt{2}\×2\×\mathrm{\π}}$

$T_{\mathrm{zj}}=T_j+T_j^{\′}\≈T_j-\frac{M_j}{U_{\mathrm{MAX}}\×2\×\mathrm{\π}\×f_c}=T_j-\frac{M_j\×T_c}{U_{\mathrm{MAX}}\×2\×\mathrm{\π}},$

F wherein _cThe ac voltage standard frequency, T _cThe ac voltage standard cycle, U _MAXThe ac signal maximal value, U _EMSBe the ac signal effective value, the condition that following formula is set up is

Perhaps

Value close to 0, i.e. requirement Value just carry out the calculating of zero crossing in scope [0.1,0.1];

Step 4), near other zero point that changes from low to high of the sampled value of electric signal, select successively n sampled point of combination in any, repeating step 2) and step 3) obtain several zero crossings time, according to these several zero crossing times, calculate the cycle of tested electric signals;

Step 5) according to the ac signal cycle that step 4) calculates, is predicted the cycle of current cycle;

Step 6), calculates current instantaneous phase at cycle and the current time of the current cycle of the time of the zero crossing that calculates when changing from low to high according to previous period ac signal, step 5) prediction.

2. the method for Quick Measurement instantaneous phase of alternating current electrical signal according to claim 1 is characterized in that: described electric signal is sampled of step 1) is constant duration sampling or not constant duration sampling.

3. the method for Quick Measurement instantaneous phase of alternating current electrical signal according to claim 1, it is characterized in that: described being sampled as of step 1) sampled to the complete cycle ripple of electric signal.

Repeating step 2), step 3) obtains several zero crossing time T 4. the method for Quick Measurement instantaneous phase of alternating current electrical signal according to claim 1, it is characterized in that: the concrete steps in the calculating tested electric signals cycle described in the step 4) are as follows: _Z1, T _Z2, T _Z3... T _Zj, T _Zj+1, T _Zj+2... T _Zn..., the cycle of tested ac signal: T then _Pj=T _Zj+1-T _Zj, the cycle of the signal that therefore obtains is followed successively by T _P1, T _P2, T _P3, T _P4..T _Pk-1, T _Pk..., k is natural number.

5. the method for Quick Measurement instantaneous phase of alternating current electrical signal according to claim 1, it is characterized in that: the ac period that the described basis of step 5) has calculated predicts that the step of current cycle period is as follows:

The cycle of a) establishing by several cycles before the ac signal that calculates is followed successively by T _Pk-3, T _Pk-2, T _Pk-1, T _Pk, the cycle of current several cycles does not exist or when can not get, makes it equal the ac voltage standard cycle;

B) periodic table of the current cycle of prediction is shown:

T _Pt=K ₁* T _Pk+ K ₂* T _Pk-1+ K ₃* T _Pk-2+ K ₄* T _Pk-3K in the formula ₁, K ₂, K ₃, K ₄Be arbitrary constant, but the K that must satisfy condition ₁+ K ₂+ K ₃+ K ₄=1.

6. the method for Quick Measurement instantaneous phase of alternating current electrical signal according to claim 1, it is characterized in that: the step 6) concrete steps are as follows: the time of establishing ac signal zero crossing from low to high is T _z, the current time is T _Ct, predicted that by step 5) the cycle of the current cycle of ac signal that obtains is T _Pt, then current instantaneous phase is expressed as:

Or be expressed as: The result who calculates is respectively the phase value that represents with the number of degrees or radian.

7. the method for each described Quick Measurement instantaneous phase of alternating current electrical signal in 6 according to claim 1 is characterized in that: during the cycle, adopt predetermined period T of current cycle at tested alternating current actual cycle skew ac voltage standard in the step 3) _c' replacement ac voltage standard cycle T _cCalculate, obtain T _c' method as follows:

The cycle of a) establishing by several cycles before the ac signal that calculates is followed successively by T _Pk-3, T _Pk-2, T _Pk-1, T _Pk, the cycle of current several cycles does not exist or when can not get, makes it equal the ac voltage standard cycle;

B) periodic table of the current cycle of prediction is shown:

T _c'=K ₁* T _Pk+ K ₂* T _Pk-1+ K ₃* T _Pk-2+ K ₄* T _Pk-3K wherein ₁, K ₂, K ₃, K ₄Be arbitrary constant, but the K that must satisfy condition ₁+ K ₂+ K ₃+ K ₄=1.

Images