CN105372489A - Method and system for obtaining any one initial-phase cosine function sequence from power signals - Google Patents

Abstract

The invention relates to a method and system for obtaining any one initial-phase cosine function sequence from power signals. After a zero initial-phase reference cosine function modulation sequence and a zero initial-phase reference sine function modulation sequence are obtained, an initial phase is arranged, a first multiplication sequence is obtained by multiplying an initial-phase cosine function by the zero initial-phase reference cosine function modulation sequence, and a second multiplication sequence is obtained by multiplying an initial-phase sine function by the zero initial-phase reference sine function modulation sequence; and the initial-phase sine function sequence is obtained by subtracting the second multiplication sequence from the first multiplication sequence. According to the invention, the initial phase of a cosine function sequence is arranged according to actual needs, the influences of random input sequences and uncertain initial phase problems are avoided, and the method and system have positive significance on improvement of accuracy of sine parameter calculation.

Description

The method and system of any initial phase cosine function sequence is obtained from electric power signal

Technical field

The present invention relates to technical field of power systems, particularly relate to a kind of method and system obtaining any initial phase cosine function sequence from electric power signal.

Background technology

The frequency measurement of electric system, phase measurement and amplitude measurement etc. are the measurement of sine parameter in itself.Fast fourier transform algorithm (FFT) and discrete fourier transform algorithm (DFT) are the basic mathematical methods calculated for sine parameter, are widely used in electric system.But along with the development of sine parameter measuring technique, fast fourier transform algorithm and discrete fourier transform algorithm Problems existing are also more aobvious outstanding, and it is difficult to the requirement meeting the calculating of electric system offset of sinusoidal parameter pin-point accuracy further.

In the measurement of electric system sine parameter, also has the measurement method of parameters that some improve, as zero hands over method, based on the mensuration of filtering, based on Wavelet Transform, based on the mensuration of neural network and the mensuration etc. based on DFT conversion.The specified power frequency of operation of power networks, near 50Hz (hertz), belongs to the sinusoidal frequency that frequency is lower.Due to the complicacy that limitation and the signal of actual signal treatment technology are formed, the data produced as signal discrete sampling quantize ground unrest impact, burst blocks that the spectrum leakage problem caused objectively is difficult to avoid, the impact of any and uncertain initial phase problem of signal, direct current in signal and subharmonic and subharmonic problem impact etc., therefore the measuring accuracy of these algorithms is low, and anti-harmonic wave and noise poor.

Summary of the invention

Based on this, be necessary for the problems referred to above, a kind of method and system obtaining any initial phase cosine function sequence from electric power signal be provided, the pin-point accuracy that sine parameter calculates can be ensured.

For solving the problems of the technologies described above, the present invention adopts following technical scheme:

From electric power signal, obtain a method for any initial phase cosine function sequence, comprise step:

According to the lower limit of frequency power signal scope, default sample frequency and default integer signal period number, obtain preliminary sequence length;

According to described preliminary sequence length, electric power signal is sampled, obtain the preliminary sequence of described electric power signal;

Frequency preliminary survey is carried out to described preliminary sequence, obtains the first synchronizing frequency of described electric power signal, obtain reference frequency according to described just synchronizing frequency;

According to described default sample frequency and described reference frequency, obtain the unit period sequence length of described electric power signal;

According to described default integer signal period number and described unit period sequence length, obtain predetermined sequence length, wherein said predetermined sequence length is odd number;

According to described predetermined sequence length and default starting point, from described preliminary sequence, obtain the first forward sequence, obtain the first anti-pleat sequence according to described first forward sequence;

Obtain the first positive phase according to described first forward sequence, obtain the first antiphase according to described first anti-pleat sequence;

The first average initial phase is obtained according to described first positive phase and described first antiphase;

According to the described first average initial phase and preset phase value, obtain phase compare value, according to described phase compare value, described default starting point and described unit period sequence length, obtain new starting point;

According to described predetermined sequence length and described new starting point, from described preliminary sequence, obtain the second forward sequence, obtain the second anti-pleat sequence according to the second forward sequence;

Obtain the second positive phase according to described second forward sequence, obtain the second antiphase according to described second anti-pleat sequence;

The second average initial phase is obtained according to described second positive phase and described second antiphase;

Described second forward sequence is added with described second anti-pleat sequence, obtains and sequence, according to described and sequence and the described second average initial phase cosine function value, obtain cosine function modulation sequence;

Described second forward sequence and described second anti-pleat sequence are subtracted each other, obtains difference sequence, according to the sine function of described difference sequence and the described second average initial phase, obtain sine function modulation sequence;

Export from described cosine function modulation sequence central point, obtain zero initial phase benchmark cosine function modulation sequence, export from described sine function modulation sequence central point, obtain zero initial phase reference sinusoidal FUNCTION MODULATION sequence;

Initial phase is set, be multiplied the cosine function of described initial phase with described zero initial phase benchmark cosine function modulation sequence acquisition first multiplication sequence, and be multiplied the sine function of described initial phase with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence acquisition second multiplication sequence;

Described first multiplication sequence is deducted described second multiplication sequence, obtains the cosine function sequence of described initial phase.

From electric power signal, obtain a system for any initial phase cosine function sequence, comprising:

Preliminary sequence length determination modul, for the lower limit according to frequency power signal scope, presets sample frequency and default integer signal period number, obtains preliminary sequence length;

Preliminary sequence acquisition module, for sampling to electric power signal according to described preliminary sequence length, obtains the preliminary sequence of described electric power signal;

Reference frequency determination module, for carrying out frequency preliminary survey to described preliminary sequence, obtains the first synchronizing frequency of described electric power signal, obtains reference frequency according to described just synchronizing frequency;

Unit period sequence length determination module, for according to described default sample frequency and described reference frequency, obtains the unit period sequence length of described electric power signal;

Predetermined sequence length determination modul, for according to described default integer signal period number and described unit period sequence length, obtain predetermined sequence length, wherein said predetermined sequence length is odd number;

First ray acquisition module, for according to described predetermined sequence length and default starting point, obtains the first forward sequence from described preliminary sequence, obtains the first anti-pleat sequence according to described first forward sequence;

First positive and negative phase determination module, for obtaining the first positive phase according to described first forward sequence, obtains the first antiphase according to described first anti-pleat sequence;

First average initial phase determination module, for obtaining the first average initial phase according to described first positive phase and described first antiphase;

New starting point determination module, for according to the described first average initial phase and preset phase value, obtains phase compare value, according to described phase compare value, described default starting point and described unit period sequence length, obtains new starting point;

Second retrieval module, for according to described predetermined sequence length and described new starting point, obtains the second forward sequence from described preliminary sequence, obtains the second anti-pleat sequence according to the second forward sequence;

Second positive and negative phase determination module, for obtaining the second positive phase according to described second forward sequence, obtains the second antiphase according to described second anti-pleat sequence;

Second average initial phase determination module, for obtaining the second average initial phase according to described second positive phase and described second antiphase;

Cosine function modulation sequence determination module, for described second forward sequence being added with described second anti-pleat sequence, obtains and sequence, according to described and sequence and the described second average initial phase cosine function value, obtains cosine function modulation sequence;

Sine function modulation sequence determination module, for described second forward sequence and described second anti-pleat sequence being subtracted each other, obtains difference sequence, according to the sine function of described difference sequence and the described second average initial phase, obtains sine function modulation sequence;

Zero initial phase modulation sequence acquisition module, for exporting from described cosine function modulation sequence central point, obtain zero initial phase benchmark cosine function modulation sequence, export from described sine function modulation sequence central point, obtain zero initial phase reference sinusoidal FUNCTION MODULATION sequence;

Multiplication sequence acquisition module, for arranging initial phase, be multiplied the cosine function of described initial phase with described zero initial phase benchmark cosine function modulation sequence acquisition first multiplication sequence, and be multiplied the sine function of described initial phase with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence acquisition second multiplication sequence;

Initial phase cosine function sequence determination module, for described first multiplication sequence is deducted described second multiplication sequence, obtains the cosine function sequence of described initial phase.

The present invention obtains the method and system of any initial phase cosine function sequence from electric power signal, the initial phase of cosine function sequence can be set according to actual needs, avoid the impact of any and uncertain initial phase problem of list entries, have positive effect to raising sine parameter accuracy in computation.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet that the present invention obtains the embodiment of the method for any initial phase cosine function sequence from electric power signal;

Fig. 2 is the schematic diagram of preliminary sequence of the present invention, the first forward sequence and the first anti-pleat sequence;

Fig. 3 is the schematic diagram of the present invention zero initial phase reference point;

Fig. 4 is the structural representation that the present invention obtains the system embodiment of any initial phase cosine function sequence from electric power signal.

Embodiment

For further setting forth the technological means that the present invention takes and the effect obtained, below in conjunction with accompanying drawing and preferred embodiment, to technical scheme of the present invention, carry out clear and complete description.

As shown in Figure 1, a kind of method obtaining any initial phase cosine function sequence from electric power signal, comprises step:

S101, the lower limit according to frequency power signal scope, default sample frequency and default integer signal period number, obtain preliminary sequence length;

S102, according to described preliminary sequence length, electric power signal to be sampled, obtain the preliminary sequence of described electric power signal;

S103, frequency preliminary survey is carried out to described preliminary sequence, obtain the first synchronizing frequency of described electric power signal, obtain reference frequency according to described just synchronizing frequency;

S104, according to described default sample frequency and described reference frequency, obtain the unit period sequence length of described electric power signal;

S105, according to described default integer signal period number and described unit period sequence length, obtain predetermined sequence length, wherein said predetermined sequence length is odd number;

S106, according to described predetermined sequence length and default starting point, from described preliminary sequence, obtain the first forward sequence, obtain the first anti-pleat sequence according to described first forward sequence;

S107, obtain the first positive phase according to described first forward sequence, obtain the first antiphase according to described first anti-pleat sequence;

S108, according to described first positive phase and described first antiphase obtain the first average initial phase;

S109, according to the described first average initial phase and preset phase value, obtain phase compare value, according to described phase compare value, described default starting point and described unit period sequence length, obtain new starting point;

S110, according to described predetermined sequence length and described new starting point, from described preliminary sequence, obtain the second forward sequence, obtain the second anti-pleat sequence according to the second forward sequence;

S111, obtain the second positive phase according to described second forward sequence, obtain the second antiphase according to described second anti-pleat sequence;

S112, according to described second positive phase and described second antiphase obtain the second average initial phase;

S113, described second forward sequence to be added with described second anti-pleat sequence, to obtain and sequence, according to described and sequence and the described second average initial phase cosine function value, acquisition cosine function modulation sequence;

S114, described second forward sequence and described second anti-pleat sequence to be subtracted each other, obtain difference sequence, according to the sine function of described difference sequence and the described second average initial phase, obtain sine function modulation sequence;

S115, to export from described cosine function modulation sequence central point, obtain zero initial phase benchmark cosine function modulation sequence, export from described sine function modulation sequence central point, obtain zero initial phase reference sinusoidal FUNCTION MODULATION sequence;

S116, initial phase is set, be multiplied the cosine function of described initial phase with described zero initial phase benchmark cosine function modulation sequence acquisition first multiplication sequence, and be multiplied the sine function of described initial phase with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence acquisition second multiplication sequence;

S117, described first multiplication sequence is deducted described second multiplication sequence, obtain the cosine function sequence of described initial phase.

Actual electrical force signal is a kind of based on the sinusoidal signal of first-harmonic composition, and if no special instructions, electric power signal all refers to fundamental signal, and frequency power signal all refers to fundamental frequency.For step S101, power system frequency scope is generally at 45Hz (hertz)-55Hz, so the lower limit f of frequency power signal scope _min45Hz can be taken as.Preset integer signal period number C _{2 π}can arrange according to actual needs, such as, by C _{2 π}be taken as 13.Preliminary sequence length can calculate according to formula (1):

$N_{start}=\left(\mathrm{int}\right)\frac{C_{2\mathrm{\π}}f}{f_{min}}---\left(1\right)$

Wherein, N _startfor preliminary sequence length; (int) expression rounds; C _{2 π}for default integer signal period number; f _minfor the lower limit of frequency power signal scope, unit Hz; F is for presetting sample frequency, unit Hz.

For step S102, can with the cosine function signal representation electric power signal of single fundamental frequency, so preliminary sequence is formula (2):

$T=\frac{1}{f}---\left(2\right)$

n＝0,1,2,3,.....,N _start-1

Wherein, X _startn () is preliminary sequence; A is signal amplitude, unit v; ω _ifor signal frequency, T is sampling interval duration, and f is for presetting sample frequency, and unit Hz, n are series of discrete number, for the initial phase of preliminary sequence, N _startfor preliminary sequence length.

For step S103, by zero friendship method, based on filtering algorithm, based on Wavelet Transformation Algorithm, based on neural network algorithm, based on DFT conversion frequency algorithm or based on the frequency algorithm of phase differential, frequency preliminary survey is carried out to preliminary sequence, obtain preliminary frequencies omega _o.In one embodiment, described reference frequency ω _s=ω _o.

For step S104, in one embodiment, the unit period sequence length of described electric power signal calculates, and is formula (3):

$N_{2\mathrm{\π}}=\left(\mathrm{int}\right)\frac{2\mathrm{\π}f}{{\mathrm{\ω}}_s}---\left(3\right)$

Wherein, N _{2 π}for unit periodic sequence length; (int) be round numbers; F is for presetting sample frequency, unit Hz; ω _sfor reference frequency.There is the error in 1 sampling interval in described unit period sequence length integer.

For step S105, predetermined sequence length is odd number, and in one embodiment, described predetermined sequence length computation, is formula (4):

Wherein, N is predetermined sequence length, and (int) is round numbers, N _{2 π}for described unit period sequence length, C _{2 π}for default integer signal period number.

For step S106, in one embodiment, default starting point can be 0.5 times of described unit period sequence length, and described first forward sequence is formula (5):

P _start＝(int)(0.5N _2π)

(5)

n＝0,1,2,3,.....,N-1

Wherein, X _startn () is preliminary sequence, X _{+ start}n () is the first forward sequence, P _startfor default starting point, N _{2 π}for described unit period sequence length, (int) is round numbers, and A is signal amplitude, unit v, ω _ifor signal frequency, T is sampling interval duration, and n is series of discrete number, be the first forward sequence initial phase, N predetermined sequence length.

Described first anti-pleat sequence, is formula (6):

X _-start(-n)＝X _+start(N-n)＝Acos(-ω _iTn+β1)

(6)

n＝0,1,2,3,.....,N-1

Wherein, X _-start(-n) is the first anti-pleat sequence, X _{+ start}n () is the first forward sequence, A is signal amplitude, unit v, ω _ifor signal frequency, T is sampling interval duration, and n is series of discrete number, and β 1 is the first anti-pleat sequence initial phase, and N is predetermined sequence length.As shown in Figure 2, be the schematic diagram of preliminary sequence, the first forward sequence and the first anti-pleat sequence.

For step S107, in one embodiment, according to the result of the first forward sequence being carried out to quadrature downconvert and integral and calculating, the first positive phase is obtained; According to the result of the first anti-pleat sequence being carried out to quadrature downconvert and integral and calculating, obtain the first antiphase.When not considering the mixing interfering frequency of quadrature downconvert, quadrature downconvert is expressed as formula (7), and integral and calculating is expressed as formula (8):

(7)

Ω＝ω _i-ω _s

n＝0,1,2,.....,N-1

Wherein, R _{+ start}n () is the first positive real sequence of mixing frequently, I _{+ start}n () is the first weakened body resistance frequency mixing sequence, R _-start(-n) is the first anti-real sequence of mixing frequently, I _-start(-n) is the first anti-empty sequence of mixing frequently, cos (ω _sor cos (-ω Tn) _stn) be the discrete cosine function of reference frequency, sin (ω _sor sin (-ω Tn) _stn) be the discrete sine function of reference frequency, Ω is signal frequency ω _iwith reference frequency ω _sfrequency difference, T is sampling interval duration, and n is series of discrete number, be the first forward sequence initial phase, β 1 is the first forward sequence initial phase, and N is predetermined sequence length.

$R_{-start}=\frac{2}{N}\underset{0}{\overset{N-1}{\Σ}}{R}_{-start}(-n)=A\frac{2\sin \left(\frac{\mathrm{\Ω}TN}{2}\right)}{\mathrm{\Ω}TN}\cos (-\frac{\mathrm{\Ω}TN}{2}+\mathrm{\β}1)$

(8)

$I_{-start}=\frac{2}{N}\underset{0}{\overset{N-1}{\Σ}}{I}_{-start}(-n)=-A\frac{2\sin \left(\frac{\mathrm{\Ω}TN}{2}\right)}{\mathrm{\Ω}TN}\sin (-\frac{\mathrm{\Ω}TN}{2}+\mathrm{\β}1)$

n＝0,1,2,.....,N-1

Wherein, R _{+ start}first positive real integrated value frequently, unit dimensionless, I _{+ start}be the first weakened body resistance frequency integrated value, unit dimensionless, R _-startbe the first anti-real integrated value frequently, unit dimensionless, I _-startbe the first anti-empty integrated value of mixing frequently, unit dimensionless, Ω is signal frequency ω _iwith reference frequency ω _sfrequency difference, T is sampling interval duration, and n is series of discrete number, and N is predetermined sequence length, be the first forward sequence initial phase, β 1 is the first anti-pleat sequence initial phase, and N is predetermined sequence length.

In one embodiment, the calculating of the first positive phase and the first antiphase, is expressed as formula (9):

${\mathrm{PH}}_{-start}=-\arctan \left(\frac{I_{-start}}{R_{-start}}\right)=-\frac{\mathrm{\Ω}TN}{2}+\mathrm{\β}1---\left(9\right)$

Wherein, PH _{+ start}be the first positive phase, PH _-startbe the first antiphase, R _{+ start}be the first positive real integrated value frequently, unit dimensionless, I _{+ start}be the first weakened body resistance frequency integrated value, unit dimensionless, R _-startbe the first anti-real integrated value frequently, unit dimensionless, I _-startbe the first anti-empty integrated value of mixing frequently, unit dimensionless, Ω is signal frequency ω _iwith reference frequency ω _sfrequency difference, T is sampling interval duration, and N is predetermined sequence length, be the first forward sequence initial phase, β 1 is the first anti-pleat sequence initial phase.

For step S108, in one embodiment, the first average initial phase computing method, are expressed as formula (10):

Wherein, PH _start-avgbe the first average initial phase, PH _{+ start}be the first positive phase, PH _-startbe the first antiphase, be the first forward sequence initial phase, β 1 is the first anti-pleat sequence initial phase.

For step S109, in one embodiment, described preset phase value can be ± π/4; According to the described first average initial phase and preset phase value, the step obtaining phase compare value can comprise:

If the described first average initial phase is more than or equal to 0 and is less than or equal to pi/2, deduct the described first average initial phase according to π/4 and obtain phase compare value;

If the described first average initial phase is more than or equal to-and pi/2 is less than or equal to 0, deducts the described first average initial phase obtain phase compare value according to-π/4.

Be specially formula (11):

${\mathrm{\ΔPH}}_{com}=\left\{\begin{array}{cc}\frac{\mathrm{\π}}{4}-{\mathrm{PH}}_{start-avg}& 0\≤{\mathrm{PH}}_{start-avg}\≤\frac{\mathrm{\π}}{2}\\ -\frac{\mathrm{\π}}{4}-{\mathrm{PH}}_{start-avg}& -\frac{\mathrm{\π}}{2}\≤{\mathrm{PH}}_{start-avg}\≤0\\ 0& {\mathrm{PH}}_{start-avg}=\±\frac{\mathrm{\π}}{4}\end{array}\right.---\left(11\right)$

Wherein, △ PH _comfor phase compare value, unit rad, PH _start-avgit is the first average initial phase.

In one embodiment, described new starting point calculates, and is formula (12):

$P_{new}=P_{start}+\left(\mathrm{int}\right)\left(\frac{{\mathrm{\ΔPH}}_{com}}{2\mathrm{\π}}{N}_{2\mathrm{\π}}\right)---\left(12\right)$

Wherein, P _newfor new starting point, unit dimensionless, P _startfor default starting point, △ PH _comfor phase compare value, unit rad, N _{2 π}for unit periodic sequence length, (int) is round numbers.

For step S110, the second forward sequence and the second anti-pleat sequence are formula (13):

X _-end(-n)＝X _+end(N-n)＝Acos(-ω _iTn+β2)(13)

n＝0,1,2,3,.....,N-1

Wherein, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, P _newfor new starting point, unit dimensionless, be the second forward sequence initial phase, β 2 is the second anti-pleat sequence initial phase, ω _ifor signal frequency, T is sampling interval duration, and n is series of discrete number, and N is predetermined sequence length.

For step S111, in one embodiment, according to the result of the second forward sequence being carried out to quadrature downconvert and digital filtering, the second positive phase is obtained; According to the result of the second anti-pleat sequence being carried out to quadrature downconvert and digital filtering, obtain the second antiphase.The i.e. computing method of the second positive phase and the second antiphase are the results calculated based on quadrature downconvert and digital filtering.In one embodiment, digital filtering can be carried out by 6 of 2 kinds of filtering parameters grade rectangular window arithmetic mean filter to the second forward sequence after quadrature downconvert and the second anti-pleat sequence.

When not considering the mixing interfering frequency of quadrature downconvert, quadrature downconvert is expressed as formula (14), and 6 grades of rectangular window arithmetic mean filter filtering calculation expressions of 2 kinds of filtering parameters are formula (15):

$R_{-end}(-n)=X_{-end}(-n)cos(-{\mathrm{\ω}}_{s}Tn)=\frac{A}{2}cos(-\mathrm{\Ω}Tn+\mathrm{\β}2)$

(14)

$I_{-end}(-n)=X_{-end}(-n)\sin (-{\mathrm{\ω}}_{s}Tn)=-\frac{A}{2}\sin (-\mathrm{\Ω}Tn+\mathrm{\β}2)$

Ω＝ω _i-ω _s

n＝0,1,2,.....,N-1

Wherein, R _{+ end}n () is the second positive real sequence of mixing frequently, I _{+ end}n () is the second weakened body resistance frequency mixing sequence, R _-end(-n) is the second anti-real sequence of mixing frequently, I _-end(-n) is the second anti-empty sequence of mixing frequently, cos (ω _sor cos (-ω Tn) _stn) be the discrete cosine function of reference frequency, sin (ω _sor sin (-ω Tn) _stn) be the discrete sine function of reference frequency, Ω is signal frequency ω _iwith reference frequency ω _sfrequency difference, T is sampling interval duration, and n is series of discrete number, be the first forward sequence initial phase, β 1 is the first anti-pleat sequence initial phase, and N is predetermined sequence length.

$\begin{array}{c}{R}_{-end}=\frac{1}{N_{D2}}\underset{n}{\overset{N_{D2}-1}{\Σ}}\frac{1}{N_{D2}}\underset{n}{\overset{N_{D2}-1}{\Σ}}\frac{1}{N_{D2}}\underset{n}{\overset{N_{D2}-1}{\Σ}}\frac{1}{N_{D1}}\underset{n}{\overset{N_{D1}-1}{\Σ}}\frac{1}{N_{D1}}\underset{n}{\overset{N_{D1}-1}{\Σ}}\frac{1}{N_{D1}}\underset{n}{\overset{N_{D1}-1}{\Σ}}{R}_{-end}(-n)\\ =\frac{A}{2}K\left(\mathrm{\Ω}\right)\cos (-\frac{{\mathrm{\ΩTN}}_d}{2}+\mathrm{\β}2)\end{array}$

$\begin{array}{c}{I}_{-end}=\frac{1}{N_{D2}}\underset{n}{\overset{N_{D2}-1}{\Σ}}\frac{1}{N_{D2}}\underset{n}{\overset{N_{D2}-1}{\Σ}}\frac{1}{N_{D2}}\underset{n}{\overset{N_{D2}-1}{\Σ}}\frac{1}{N_{D1}}\underset{n}{\overset{N_{D1}-1}{\Σ}}\frac{1}{N_{D1}}\underset{n}{\overset{N_{D1}-1}{\Σ}}\frac{1}{N_{D1}}\underset{n}{\overset{N_{D1}-1}{\Σ}}{I}_{-end}(-n)\\ =-\frac{A}{2}K\left(\mathrm{\Ω}\right)\sin (-\frac{{\mathrm{\ΩTN}}_d}{2}+\mathrm{\β}2)\end{array}$

$K\left(\mathrm{\Ω}\right)={\[\frac{2\sin \left(\frac{{\mathrm{\ΩTN}}_{D1}}{2}\right)}{{\mathrm{\ΩTN}}_{D1}}\]}^3{\[\frac{2\sin \left(\frac{{\mathrm{\ΩTN}}_{D2}}{2}\right)}{{\mathrm{\ΩTN}}_{D2}}\]}^3$

(15)

N _D＝3N _D1+3N _D2

N _D≤N

n＝0,1,2,3,....,N _D-1

Wherein, R _{+ end}be the second positive real digital filtering final value frequently, unit dimensionless; I _{+ end}be the second weakened body resistance frequency digital filtering final value, unit dimensionless; R _-endbe the second anti-digital filtering final value, unit dimensionless; I _-endbe the second anti-empty digital filtering final value frequently, unit dimensionless; Ω is signal frequency ω _iwith reference frequency ω _sfrequency difference; K (Ω) for digital filtering is in the amplitude gain of frequency difference Ω, unit dimensionless; T is sampling interval duration; it is the second forward sequence initial phase; β 2 is the second anti-pleat sequence initial phase; N _d1for filtering parameter 1, namely to N _d1individual continuous discrete value is added, and then gets its arithmetic mean and exports as this filter value; N _d2for filtering parameter 2, namely to N _d2individual continuous discrete value is added, and then gets its arithmetic mean and exports as this filter value; N _dfor digital filtering uses sequence length, be quantitatively the summation of 6 grades of rectangular window arithmetic mean filter filtering parameters, be less than or equal to predetermined sequence length N.

In one embodiment, filtering parameter N _d1value is 1.5 times of the unit period sequence length of described reference frequency, and object carries out degree of depth suppression to the mixing interfering frequency that 1/3 subharmonic produces; Filtering parameter N _d2value is 2 times of the unit period sequence length of described reference frequency, and object carries out degree of depth suppression to the mixing interfering frequency that direct current, 1/2 gradation, subharmonic etc. produce.6 grades of rectangular window arithmetic mean filter filtering of 2 kinds of filtering parameters calculate 10.5 times that need to use signal period sequence length.

Filtering parameter N _d1with filtering parameter N _d2be calculated as formula (16):

N ^D1＝(int)(1.5N ^2π)

(16)

N _D2＝2N _2π

Wherein, N _d1for digital filter parameters 1, unit dimensionless, (int) is round numbers, N _d2for digital filter parameters 2, unit dimensionless, N _{2 π}for unit periodic sequence length.

In one embodiment, the computing method of the second positive phase and the second antiphase, are expressed as formula (17):

(17)

${\mathrm{PH}}_{-end}=-arctan\left(\frac{I_{-end}}{R_{-end}}\right)=-\frac{{\mathrm{\ΩTN}}_D}{2}+\mathrm{\β}2$

Wherein, PH _{+ end}be the second positive phase, PH _-endbe the second antiphase, R _{+ end}be the second positive real integrated value frequently, unit dimensionless, I _{+ end}be the second weakened body resistance frequency integrated value, unit dimensionless, R _-endbe the second anti-real integrated value frequently, unit dimensionless, I _-endbe the second anti-empty integrated value of mixing frequently, unit dimensionless, Ω is signal frequency ω _iwith reference frequency ω _sfrequency difference, T is sampling interval duration, N _dfor digital filtering uses sequence length, be the second forward sequence initial phase, β 2 is the second anti-pleat sequence initial phase.

For step S112, the second average initial phase computing method, are expressed as formula (18):

Wherein, PH _end-avgbe the second average initial phase, PH _{+ end}be the second positive phase, PH _-endbe the second antiphase, be the second forward sequence initial phase, β 2 is the second forward sequence initial phase.

For step S113, cosine function modulation sequence is expressed as formula (19):

n＝0,1,2,3,.....,N-1

Wherein, X _cosn () is cosine function modulation sequence; X _{+ end}n () is the second forward sequence; X _-end(-n) is the second anti-pleat sequence; PH _end-avgit is the second average initial phase; A is cosine function modulation sequence amplitude, unit v; for cosine function modulation sequence initial phase, ω _ifor signal frequency, T is sampling interval duration, and n is series of discrete number, and N is predetermined sequence length, be the second forward sequence initial phase, β 2 is the second anti-pleat sequence initial phase.

For step S114, sine function modulation sequence is expressed as formula (20):

n＝0,1,2,3,.....,N-1

Wherein, X _sinn () is sine function modulation sequence, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, PH _end-avgbe the second average initial phase, A is sine function modulation sequence amplitude, unit v, for cosine function modulation sequence initial phase, ω _isignal frequency, T is sampling interval duration, and n is series of discrete number, and N is predetermined sequence length, be the second forward sequence initial phase, β 2 is the second anti-pleat sequence initial phase.

For step S115, in one embodiment, zero initial phase benchmark cosine function modulation sequence is expressed as formula (21):

$\begin{array}{c}X{0}_{\cos }\left(n\right)=X_{\cos }(\frac{N-1}{2}+n)=A\cos \left({\mathrm{\ω}}_i{T}_{n}n\right)\\ n=0,1,2,3,\mathrm{...},\frac{N-1}{2}-1\end{array}---\left(21\right)$

Wherein, X0 _sinn () is zero initial phase benchmark cosine function modulation sequence, A is cosine function modulation sequence amplitude, unit v, ω _isignal frequency, T is sampling interval duration, and n is series of discrete number, and N is predetermined sequence length.

In one embodiment, zero initial phase reference sinusoidal FUNCTION MODULATION sequence is expressed as formula (22):

$\begin{array}{c}X{0}_{\sin }\left(n\right)=X_{\sin }(\frac{N-1}{2}+n)=A\sin \left({\mathrm{\ω}}_i{T}_{n}n\right)\\ n=0,1,2,3,\mathrm{...},\frac{N-1}{2}-1\end{array}---\left(22\right)$

Wherein, X0 _sinn () is zero initial phase reference sinusoidal FUNCTION MODULATION sequence, A is sine function modulation sequence amplitude, unit v, ω _isignal frequency, T is sampling interval duration, and n is series of discrete number, and N is predetermined sequence length.Zero initial phase reference point figure as shown in Figure 3.

For step S116, initial phase scope at 0 ~ ± pi/2.In one embodiment, the first multiplication sequence obtained and the expression formula of the second multiplication sequence are (23):

$n=0,1,2,3,\mathrm{.....},\frac{N-1}{2}-1---\left(23\right)$

Wherein, X1 (n) is the first multiplication sequence, and X2 (n) is the second multiplication sequence, for described initial phase, for the sine function of described initial phase, X0 _cosn () is described zero initial phase benchmark cosine function modulation sequence, for the cosine function of described initial phase, X0 _sinn () is described zero initial phase reference sinusoidal FUNCTION MODULATION sequence, n is series of discrete number, and N is predetermined sequence length.

For step S117, the cosine function sequence of described initial phase is expressed as formula (24):

$n=0,1,2,3,\mathrm{.....},\frac{N-1}{2}-1---\left(24\right)$

Wherein, for the cosine function sequence of described initial phase.

Based on same inventive concept, the present invention also provides a kind of system obtaining any initial phase cosine function sequence from electric power signal, is described in detail embodiments of systems of the invention below in conjunction with accompanying drawing.

As shown in Figure 4, a kind of system obtaining any initial phase cosine function sequence from electric power signal, comprising:

Preliminary sequence length determination modul 101, for the lower limit according to frequency power signal scope, presets sample frequency and default integer signal period number, obtains preliminary sequence length;

Preliminary sequence acquisition module 102, for sampling to electric power signal according to described preliminary sequence length, obtains the preliminary sequence of described electric power signal;

Reference frequency determination module 103, for carrying out frequency preliminary survey to described preliminary sequence, obtains the first synchronizing frequency of described electric power signal, obtains reference frequency according to described just synchronizing frequency;

Unit period sequence length determination module 104, for according to described default sample frequency and described reference frequency, obtains the unit period sequence length of described electric power signal;

Predetermined sequence length determination modul 105, for according to described default integer signal period number and described unit period sequence length, obtain predetermined sequence length, wherein said predetermined sequence length is odd number;

First ray acquisition module 106, for according to described predetermined sequence length and default starting point, obtains the first forward sequence from described preliminary sequence, obtains the first anti-pleat sequence according to described first forward sequence;

First positive and negative phase determination module 107, for obtaining the first positive phase according to described first forward sequence, obtains the first antiphase according to described first anti-pleat sequence;

First average initial phase determination module 108, for obtaining the first average initial phase according to described first positive phase and described first antiphase;

New starting point determination module 109, for according to the described first average initial phase and preset phase value, obtains phase compare value, according to described phase compare value, described default starting point and described unit period sequence length, obtains new starting point;

Second retrieval module 110, for according to described predetermined sequence length and described new starting point, obtains the second forward sequence from described preliminary sequence, obtains the second anti-pleat sequence according to the second forward sequence;

Second positive and negative phase determination module 111, for obtaining the second positive phase according to described second forward sequence, obtains the second antiphase according to described second anti-pleat sequence;

Second average initial phase determination module 112, for obtaining the second average initial phase according to described second positive phase and described second antiphase;

Cosine function modulation sequence determination module 113, for described second forward sequence being added with described second anti-pleat sequence, obtains and sequence, according to described and sequence and the described second average initial phase cosine function value, obtains cosine function modulation sequence;

Sine function modulation sequence determination module 114, for described second forward sequence and described second anti-pleat sequence being subtracted each other, obtains difference sequence, according to the sine function of described difference sequence and the described second average initial phase, obtains sine function modulation sequence;

Zero initial phase modulation sequence acquisition module 115, for exporting from described cosine function modulation sequence central point, obtain zero initial phase benchmark cosine function modulation sequence, export from described sine function modulation sequence central point, obtain zero initial phase reference sinusoidal FUNCTION MODULATION sequence;

Multiplication sequence acquisition module 116, for arranging initial phase, be multiplied the cosine function of described initial phase with described zero initial phase benchmark cosine function modulation sequence acquisition first multiplication sequence, and be multiplied the sine function of described initial phase with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence acquisition second multiplication sequence;

Initial phase cosine function sequence determination module 117, for described first multiplication sequence is deducted described second multiplication sequence, obtains the cosine function sequence of described initial phase.

In one embodiment, described cosine function modulation sequence determination module 113 can according to expression formula obtain cosine function modulation sequence X _cos(n), wherein, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, PH _end-avgit is the second average initial phase.

In one embodiment, described sine function modulation sequence determination module 114 can according to expression formula obtain sine function modulation sequence X _sin(n), wherein, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, PH _end-avgit is the second average initial phase.

In one embodiment, described zero initial phase modulation sequence acquisition module 115 can according to expression formula obtain described zero initial phase benchmark cosine function modulation sequence X0 _cos(n), wherein, n=0,1,2,3 ... .., n is series of discrete number, and N is predetermined sequence length, X _cosn () is cosine function modulation sequence.

In one embodiment, described zero initial phase modulation sequence acquisition module 115 can according to expression formula obtain described zero initial phase reference sinusoidal FUNCTION MODULATION sequence X 0 _sin(n), wherein, n=0,1,2,3 ... .., n is series of discrete number, and N is predetermined sequence length, X _sinn () is sine function modulation sequence.

Described multiplication sequence acquisition module 116 can according to expression formula obtain the first multiplication sequence X1 (n), according to expression formula obtain the second multiplication sequence X2 (n);

Wherein, for described initial phase, for the sine function of described initial phase, X0 _cosn () is described zero initial phase benchmark cosine function modulation sequence, for the cosine function of described initial phase, X0 _sinn () is described zero initial phase reference sinusoidal FUNCTION MODULATION sequence, n=0,1,2,3 ... .., n is series of discrete number, and N is predetermined sequence length.

Other technical characteristic of present system is identical with the inventive method, does not repeat them here.

Each technical characteristic of the above embodiment can combine arbitrarily, for making description succinct, the all possible combination of each technical characteristic in above-described embodiment is not all described, but, as long as the combination of these technical characteristics does not exist contradiction, be all considered to be the scope that this instructions is recorded.

The above embodiment only have expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but can not therefore be construed as limiting the scope of the patent.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.

Claims (10)

1. from electric power signal, obtain a method for any initial phase cosine function sequence, it is characterized in that, comprise step:

According to the lower limit of frequency power signal scope, default sample frequency and default integer signal period number, obtain preliminary sequence length;

According to described preliminary sequence length, electric power signal is sampled, obtain the preliminary sequence of described electric power signal;

Frequency preliminary survey is carried out to described preliminary sequence, obtains the first synchronizing frequency of described electric power signal, obtain reference frequency according to described just synchronizing frequency;

According to described default sample frequency and described reference frequency, obtain the unit period sequence length of described electric power signal;

According to described default integer signal period number and described unit period sequence length, obtain predetermined sequence length, wherein said predetermined sequence length is odd number;

According to described predetermined sequence length and default starting point, from described preliminary sequence, obtain the first forward sequence, obtain the first anti-pleat sequence according to described first forward sequence;

Obtain the first positive phase according to described first forward sequence, obtain the first antiphase according to described first anti-pleat sequence;

The first average initial phase is obtained according to described first positive phase and described first antiphase;

According to the described first average initial phase and preset phase value, obtain phase compare value, according to described phase compare value, described default starting point and described unit period sequence length, obtain new starting point;

According to described predetermined sequence length and described new starting point, from described preliminary sequence, obtain the second forward sequence, obtain the second anti-pleat sequence according to the second forward sequence;

Obtain the second positive phase according to described second forward sequence, obtain the second antiphase according to described second anti-pleat sequence;

The second average initial phase is obtained according to described second positive phase and described second antiphase;

Described second forward sequence is added with described second anti-pleat sequence, obtains and sequence, according to described and sequence and the described second average initial phase cosine function value, obtain cosine function modulation sequence;

Described second forward sequence and described second anti-pleat sequence are subtracted each other, obtains difference sequence, according to the sine function of described difference sequence and the described second average initial phase, obtain sine function modulation sequence;

Export from described cosine function modulation sequence central point, obtain zero initial phase benchmark cosine function modulation sequence, export from described sine function modulation sequence central point, obtain zero initial phase reference sinusoidal FUNCTION MODULATION sequence;

Initial phase is set, be multiplied the cosine function of described initial phase with described zero initial phase benchmark cosine function modulation sequence acquisition first multiplication sequence, and be multiplied the sine function of described initial phase with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence acquisition second multiplication sequence;

Described first multiplication sequence is deducted described second multiplication sequence, obtains the cosine function sequence of described initial phase.

2. the method obtaining any initial phase cosine function sequence from electric power signal according to claim 1, is characterized in that, according to expression formula obtain the first multiplication sequence X1 (n), according to expression formula obtain the second multiplication sequence X2 (n);

Wherein, for described initial phase, for the sine function of described initial phase, X0 _cosn () is described zero initial phase benchmark cosine function modulation sequence, for the cosine function of described initial phase, X0 _sinn () is described zero initial phase reference sinusoidal FUNCTION MODULATION sequence, n is series of discrete number, and N is predetermined sequence length.

3. the method obtaining any initial phase cosine function sequence from electric power signal according to claim 2, is characterized in that, according to expression formula obtain described zero initial phase benchmark cosine function modulation sequence X0 _cos(n), wherein, n is series of discrete number, and N is predetermined sequence length, X _cosn () is cosine function modulation sequence.

4. the method obtaining any initial phase cosine function sequence from electric power signal according to claim 2, is characterized in that, according to expression formula obtain described zero initial phase reference sinusoidal FUNCTION MODULATION sequence X 0 _sin(n), wherein, n is series of discrete number, and N is predetermined sequence length, X _sinn () is sine function modulation sequence.

5. the method obtaining any initial phase cosine function sequence from electric power signal according to Claims 1-4 any one, is characterized in that:

According to expression formula obtain cosine function modulation sequence X _cos(n), wherein, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, PH _end-avgit is the second average initial phase;

According to expression formula obtain sine function modulation sequence X _sin(n), wherein, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, PH _end-avgit is the second average initial phase.

6. from electric power signal, obtain a system for any initial phase cosine function sequence, it is characterized in that, comprising:

Preliminary sequence length determination modul, for the lower limit according to frequency power signal scope, presets sample frequency and default integer signal period number, obtains preliminary sequence length;

Preliminary sequence acquisition module, for sampling to electric power signal according to described preliminary sequence length, obtains the preliminary sequence of described electric power signal;

Reference frequency determination module, for carrying out frequency preliminary survey to described preliminary sequence, obtains the first synchronizing frequency of described electric power signal, obtains reference frequency according to described just synchronizing frequency;

Unit period sequence length determination module, for according to described default sample frequency and described reference frequency, obtains the unit period sequence length of described electric power signal;

Predetermined sequence length determination modul, for according to described default integer signal period number and described unit period sequence length, obtain predetermined sequence length, wherein said predetermined sequence length is odd number;

First ray acquisition module, for according to described predetermined sequence length and default starting point, obtains the first forward sequence from described preliminary sequence, obtains the first anti-pleat sequence according to described first forward sequence;

First positive and negative phase determination module, for obtaining the first positive phase according to described first forward sequence, obtains the first antiphase according to described first anti-pleat sequence;

First average initial phase determination module, for obtaining the first average initial phase according to described first positive phase and described first antiphase;

New starting point determination module, for according to the described first average initial phase and preset phase value, obtains phase compare value, according to described phase compare value, described default starting point and described unit period sequence length, obtains new starting point;

Second retrieval module, for according to described predetermined sequence length and described new starting point, obtains the second forward sequence from described preliminary sequence, obtains the second anti-pleat sequence according to the second forward sequence;

Second positive and negative phase determination module, for obtaining the second positive phase according to described second forward sequence, obtains the second antiphase according to described second anti-pleat sequence;

Second average initial phase determination module, for obtaining the second average initial phase according to described second positive phase and described second antiphase;

Cosine function modulation sequence determination module, for described second forward sequence being added with described second anti-pleat sequence, obtains and sequence, according to described and sequence and the described second average initial phase cosine function value, obtains cosine function modulation sequence;

Sine function modulation sequence determination module, for described second forward sequence and described second anti-pleat sequence being subtracted each other, obtains difference sequence, according to the sine function of described difference sequence and the described second average initial phase, obtains sine function modulation sequence;

Zero initial phase modulation sequence acquisition module, for exporting from described cosine function modulation sequence central point, obtain zero initial phase benchmark cosine function modulation sequence, export from described sine function modulation sequence central point, obtain zero initial phase reference sinusoidal FUNCTION MODULATION sequence;

Multiplication sequence acquisition module, for arranging initial phase, be multiplied the cosine function of described initial phase with described zero initial phase benchmark cosine function modulation sequence acquisition first multiplication sequence, and be multiplied the sine function of described initial phase with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence acquisition second multiplication sequence;

Initial phase cosine function sequence determination module, for described first multiplication sequence is deducted described second multiplication sequence, obtains the cosine function sequence of described initial phase.

7. the system obtaining any initial phase cosine function sequence from electric power signal according to claim 6, it is characterized in that, described multiplication sequence acquisition module is according to expression formula obtain the first multiplication sequence X1 (n), according to expression formula obtain the second multiplication sequence X2 (n);

Wherein, for described initial phase, for the sine function of described initial phase, X0 _cosn () is described zero initial phase benchmark cosine function modulation sequence, for the cosine function of described initial phase, X0 _sinn () is described zero initial phase reference sinusoidal FUNCTION MODULATION sequence, n is series of discrete number, and N is predetermined sequence length.

8. the system obtaining any initial phase cosine function sequence from electric power signal according to claim 7, is characterized in that, described zero initial phase modulation sequence acquisition module is according to expression formula obtain described zero initial phase benchmark cosine function modulation sequence X0 _cos(n), wherein, n is series of discrete number, and N is predetermined sequence length, X _cosn () is cosine function modulation sequence.

9. the system obtaining any initial phase cosine function sequence from electric power signal according to claim 7, is characterized in that, described zero initial phase modulation sequence acquisition module is according to expression formula obtain described zero initial phase reference sinusoidal FUNCTION MODULATION sequence X 0 _sin(n), wherein, n is series of discrete number, and N is predetermined sequence length, X _sinn () is sine function modulation sequence.

10. the system obtaining any initial phase cosine function sequence from electric power signal according to claim 6 to 9 any one, is characterized in that:

Described cosine function modulation sequence determination module is according to expression formula obtain cosine function modulation sequence X _cos(n), wherein, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, PH _end-avgit is the second average initial phase;

Described sine function modulation sequence determination module is according to expression formula obtain sine function modulation sequence X _sin(n), wherein, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, PH _end-avgit is the second average initial phase.