CN105548690A - Frequency measurement method and system based on zero initial phase reference sine function frequency multiplication sequence - Google Patents

Abstract

The invention relates to a frequency measurement method and system based on a zero initial phase reference sine function frequency multiplication sequence. The method includes the steps of: obtaining a real frequency mixing sequence and an imaginary frequency mixing sequence, then performing digital filtering and integration on the real frequency mixing sequence and the imaginary frequency mixing sequence, obtaining a real frequency integral value and an imaginary frequency integral value, obtaining the phase of a zero initial phase reference sine function frequency multiplication sequence according to the real frequency integral value and the imaginary frequency integral value, and obtaining the frequency of an electric power signal according to the phase. Obtaining the frequency of the electric power signal through the method provided by the invention can remarkably improve the degree of accuracy of frequency measurement of the electric power signal.

Description

Based on zero initial phase reference sinusoidal function frequency multiplication sequence frequency measuring method and system

Technical field

The present invention relates to technical field of power systems, particularly relate to a kind of based on zero initial phase reference sinusoidal function frequency multiplication sequence frequency measuring method and system.

Background technology

The frequency measurement, phase measurement, amplitude measurement etc. of electric system are the measurement of sine parameter in itself.Fourier transform is the basic skills realizing sine parameter measurement, is widely used in electric system.But along with the development of sine parameter measuring technique, Fourier transform Problems existing is 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, the mensuration based on neural network, the mensuration etc. that converts based on DFT (DiscreteFourierTransform, discrete Fourier transformation).Because the specified power frequency of operation of power networks is near 50Hz (hertz), belong to the sinusoidal frequency that frequency is lower, and interference is there is in the electric power signal of reality, such as humorous wave interference, electric load among a small circle in random fluctuation produce similar white noise interference etc., under interference environment, the problem that the ubiquitous accuracy of measurement of these algorithms is not high.

Summary of the invention

Based on this, be necessary for the problems referred to above, provide a kind of based on zero initial phase reference sinusoidal function frequency multiplication sequence frequency measuring method and system, the accuracy that frequency power signal is measured can be improved.

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

Based on a frequency measurement method for zero initial phase reference sinusoidal function times frequency 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;

Described default integer signal period number is multiplied with described unit period sequence length, obtains preprocessing sequence length;

According to described preprocessing sequence length, from the preliminary sequence of described electric power signal, obtain preprocessing sequence;

Carry out comb filtering process to described preprocessing sequence, obtain comb filtering sequence, wherein comb filtering sequence length is the residue length of described preprocessing sequence after carrying out comb filtering process;

Determine the ratio integer of described comb filtering sequence length and described unit period sequence length, obtain predetermined sequence length according to described ratio integer and described unit period sequence length, wherein said ratio integer is odd number, and described predetermined sequence length is odd number;

According to described predetermined sequence length and default starting point, from described comb filtering 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 comb filtering 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;

Be multiplied by 2 again after being multiplied with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence by described zero initial phase benchmark cosine function modulation sequence, obtain zero initial phase reference sinusoidal function times frequency sequence;

Described zero initial phase reference sinusoidal function times frequency sequence is multiplied with the discrete cosine function of 2 times of reference frequencies respectively and is multiplied with the discrete sine function of 2 times of reference frequencies, obtain the real sequence of mixing frequently and the empty sequence of mixing frequently;

Respectively digital filtering is carried out to described real mixing sequence frequently and the described empty sequence of mixing frequently, obtain real filtered sequence and imaginary frequency filtering sequence frequently;

Respectively integration is carried out to described real filtered sequence and described imaginary frequency filtering sequence frequently, obtain real integrated value frequently and empty integrated value frequently;

According to described real integrated value frequently and empty integrated value frequently, obtain the phase place of zero initial phase reference sinusoidal function times frequency sequence, obtain the frequency of electric power signal according to described phase place.

Based on a frequency measuring system for zero initial phase reference sinusoidal function times frequency 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;

Preprocessing sequence length determination modul, for being multiplied with described unit period sequence length by described default integer signal period number, obtains preprocessing sequence length;

Preprocessing sequence acquisition module, for according to described preprocessing sequence length, obtains preprocessing sequence from the preliminary sequence of described electric power signal;

Comb filtering sequence determination module, for carrying out comb filtering process to described preprocessing sequence, obtain comb filtering sequence, wherein comb filtering sequence length is the residue length of described preprocessing sequence after carrying out comb filtering process;

Predetermined sequence length determination modul, for determining the ratio integer of described comb filtering sequence length and described unit period sequence length, predetermined sequence length is obtained according to described ratio integer and described unit period sequence length, wherein said ratio integer is odd number, and described 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 comb filtering 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 comb filtering 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;

Zero initial phase reference sinusoidal function times frequency sequence determination sequence, is multiplied by 2 again, obtains zero initial phase reference sinusoidal function times frequency sequence after being multiplied with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence by described zero initial phase benchmark cosine function modulation sequence;

Mixing sequence determination module, to be multiplied with the discrete sine function of 2 times of reference frequencies for being multiplied with the discrete cosine function of 2 times of reference frequencies respectively by described zero initial phase reference sinusoidal function times frequency sequence, obtains the real sequence of mixing frequently and the empty sequence of mixing frequently;

Filtered sequence determination module, for carrying out digital filtering to described real mixing sequence frequently and the described empty sequence of mixing frequently respectively, obtains real filtered sequence and imaginary frequency filtering sequence frequently;

Integrated value determination module, for carrying out integration to described real filtered sequence and described imaginary frequency filtering sequence frequently respectively, obtains real integrated value frequently and empty integrated value frequently;

Frequency power signal determination module, for according to described real integrated value frequently and empty integrated value frequently, obtains the phase place of zero initial phase reference sinusoidal function times frequency sequence, obtains the frequency of electric power signal according to described phase place.

The present invention is based on zero initial phase reference sinusoidal function frequency multiplication sequence frequency measuring method and system, obtain the real sequence of mixing frequently and the empty sequence of mixing frequently, then digital filtering and integration are carried out to described real mixing sequence frequently and the described empty sequence of mixing frequently, obtain real integrated value frequently and empty integrated value frequently, according to described real integrated value frequently and empty integrated value frequently, obtain the phase place of zero initial phase reference sinusoidal function times frequency sequence, obtain the frequency of electric power signal according to described phase place.Obtained the frequency of electric power signal by mode of the present invention, the accuracy that frequency power signal is measured can be significantly improved.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet that the present invention is based on zero initial phase reference sinusoidal function frequency multiplication sequence frequency measuring method embodiment;

Fig. 2 is the schematic diagram of comb filtering process of the present invention in frequency domain amplitude versus frequency characte;

Fig. 3 is the schematic diagram of comb filtering sequence of the present invention, the first forward sequence, the first anti-pleat sequence;

Fig. 4 is the pictorial diagram of the present invention zero initial phase reference point;

Fig. 5 is the structural representation that the present invention is based on zero initial phase reference sinusoidal function frequency multiplication sequence frequency measuring system embodiment.

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 based on zero initial phase reference sinusoidal function frequency multiplication sequence frequency measuring method, comprise 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, described default integer signal period number to be multiplied with described unit period sequence length, to obtain preprocessing sequence length;

S106, according to described preprocessing sequence length, from the preliminary sequence of described electric power signal, obtain preprocessing sequence;

S107, carry out comb filtering process to described preprocessing sequence, obtain comb filtering sequence, wherein comb filtering sequence length is the residue length of described preprocessing sequence after carrying out comb filtering process;

S108, determine the ratio integer of described comb filtering sequence length and described unit period sequence length, predetermined sequence length is obtained according to described ratio integer and described unit period sequence length, wherein said ratio integer is odd number, and described predetermined sequence length is odd number;

S109, according to described predetermined sequence length and default starting point, from described comb filtering sequence, obtain the first forward sequence, obtain the first anti-pleat sequence according to described first forward sequence;

S110, obtain the first positive phase according to described first forward sequence, obtain the first antiphase according to described first anti-pleat sequence;

S111, according to described first positive phase and described first antiphase obtain the first average initial phase;

S112, 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;

S113, according to described predetermined sequence length and described new starting point, from described comb filtering sequence, obtain the second forward sequence, obtain the second anti-pleat sequence according to the second forward sequence;

S114, obtain the second positive phase according to described second forward sequence, obtain the second antiphase according to described second anti-pleat sequence;

S115, according to described second positive phase and described second antiphase obtain the second average initial phase;

S116, 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;

S117, 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;

S118, 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;

S119, described zero initial phase benchmark cosine function modulation sequence is multiplied with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence after be multiplied by 2 again, obtain zero initial phase reference sinusoidal function times frequency sequence;

S120, being multiplied with the discrete cosine function of 2 times of reference frequencies respectively by described zero initial phase reference sinusoidal function times frequency sequence is multiplied with the discrete sine function of 2 times of reference frequencies, obtains the real sequence of mixing frequently and the empty sequence of mixing frequently;

S121, respectively digital filtering is carried out to described real mixing sequence frequently and the described empty sequence of mixing frequently, obtain real filtered sequence and imaginary frequency filtering sequence frequently;

S122, respectively integration is carried out to described real filtered sequence and described imaginary frequency filtering sequence frequently, obtain real integrated value frequently and empty integrated value frequently;

S123, according to described real integrated value frequently and empty integrated value frequently, obtain the phase place of zero initial phase reference sinusoidal function times frequency sequence, obtain the frequency of electric power signal according to described phase place.

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 17.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):

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, described preprocessing sequence length is formula (4):

N _set＝C _2πN _2π(4)

Wherein, N _setfor preprocessing sequence length; C _{2 π}for default integer signal period number; N _{2 π}for unit periodic sequence length.

For step S106, in one embodiment, obtain preprocessing sequence, be formula (5):

Wherein, X _setn () is preprocessing sequence, X _startn () is preliminary sequence, N _setfor preprocessing sequence length.

There are subharmonic, even-order harmonic, odd harmonic etc. in electric power signal, in optical mixing process, the mixing interfering frequency produced has a strong impact on the accuracy in computation of sine parameter, and carrying out comb filtering process effectively can suppress from source to the factor that mixing interfering frequency produces.

For step S107, list entries different for 2 starting points is subtracted each other, the frequency domain amplitude-frequency filtering characteristic of pectination can be obtained, referred to as comb filtering process.The interval of 2 list entries is defined as comb filtering parameter, and the process of single-stage comb filtering is expressed as formula (6):

$\begin{array}{c}{X}_L\left(n\right)=\frac{1}{2}{X}_{set}\left(n\right)-\frac{1}{2}{X}_{set}\left(N_L+n\right)\\ n=0,1,2,3,\mathrm{.......},N_{set}-N_L-1\\ N_L=\left(\mathrm{int}\right)\left(0.5N_{2\mathrm{\π}}\right)\end{array}---\left(6\right)$

Wherein, X _ln () is single-stage comb filtering output sequence; X _setn () is preprocessing sequence; X _set(N _l+ n) be from N _linitial preprocessing sequence; N _lbe 2 train interval or single-stage comb filtering parameter; N _setfor preprocessing sequence length; N _{2 π}for unit periodic sequence length.Comb filtering Parameter N _lvalue is unit periodic sequence length N _{2 π}0.5 times, can suppress even-order harmonic and subharmonic be decayed.

In one embodiment, comb filtering process can be carried out by comb filter to described preprocessing sequence.Due to reference frequency there is error, there is integer error in comb filtering parameter, in order to improve comb-filter effects, comb filtering process can be carried out by 8 grades of comb filter, being expressed as formula (7):

Wherein, X _8Ln () is 8 grades of comb filter or comb filtering sequence; Filter [8, N _l, X _set(n)] in 8 to represent comb filtering progression be 8, N _lfor single-stage comb filtering parameter, X _setn () is preprocessing sequence; K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, T is sampling interval duration; for comb filtering sequence initial phase; N _setfor preprocessing sequence length.

Comb filtering process needs applying unit periodic sequence length N _{2 π}4 times of sequence lengths.Comb filtering process in frequency domain amplitude versus frequency characte as shown in Figure 2.

For step S108, in one embodiment, ratio integer is set to odd number, determines the ratio integer of described comb filtering sequence length and described unit period sequence length, is formula (8):

Wherein, k is described ratio integer, N _setfor preprocessing sequence length, N _lfor single-stage comb filtering parameter, N _{2 π}for unit periodic sequence length.

In one embodiment, predetermined sequence length is set to odd number, and predetermined sequence length computation is formula (9):

Wherein, N is predetermined sequence length, and k is described ratio integer, N _{2 π}for unit periodic sequence length.

For step S109, in one embodiment, default starting point can be 0.5 times of described unit period sequence length, and described first forward sequence is formula (10):

Wherein, X _8Ln () is 8 grades of comb filtering sequences, X _{+ start}n () is the first forward sequence, P _startfor default starting point, N _{2 π}for unit periodic sequence length, (int) is round numbers, and A is signal amplitude, unit v, ω _ifor signal frequency, K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, T is sampling interval duration, and n is series of discrete number, be the first forward sequence initial phase, N is predetermined sequence length.

In one embodiment, described first anti-pleat sequence is formula (11):

$\begin{array}{c}{X}_{-\mathrm{start}}(-n)=X_{+\mathrm{start}}(N-n)=\mathrm{AK}\left({\mathrm{\ω}}_i\right)\cos (-{\mathrm{\ω}}_i\mathrm{Tn}+\mathrm{\β}1)\\ n=\mathrm{0,1,2,3},.....,N-1\end{array}---\left(11\right)$

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.Comb filtering sequence, the first forward sequence and the first anti-pleat sequence pattern are expressed as shown in Figure 3.

For step S110, the calculating of the first positive phase and the first antiphase is the result based on quadrature downconvert and integral and calculating.

When not considering the mixing interfering frequency of quadrature downconvert, quadrature downconvert is expressed as formula (12), and integral and calculating is expressed as formula (13):

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, K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, be the first forward sequence initial phase, β 1 is the first forward sequence initial phase, and N is predetermined sequence length.

Wherein, 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 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 (14):

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 S111, in one embodiment, the first average initial phase computing method, are expressed as formula (15):

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 S112, 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 (16):

${\mathrm{\ΔPH}}_{com}=\left\{\begin{array}{cc}\frac{\mathrm{\π}}{4}-{\mathrm{PH}}_{start-avg}& 0\≤{\mathrm{PH}}_{start-avg}\≤\frac{\mathrm{\π}}{2}\\ -\frac{\mathrm{\π}}{4}-{\mathrm{PH}}_{start-avg}& -\frac{\mathrm{\π}}{2}\≤{\mathrm{PH}}_{start-avg}\≤0\\ 0& {\mathrm{PH}}_{start-avg}=\±\frac{\mathrm{\π}}{4}\end{array}\right.---\left(16\right)$

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 (17):

$P_{new}=P_{start}+\left(\mathrm{int}\right)\left(\frac{{\mathrm{\ΔPH}}_{com}}{2\mathrm{\π}}{N}_{2\mathrm{\π}}\right)---\left(17\right)$

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 S113, the second forward sequence and the second anti-pleat sequence are formula (18):

Wherein, X _8Ln () is 8 grades of comb filtering sequences, X _{+ end}n () is the second forward sequence, X _-end(-n) is the second anti-pleat sequence, P _newfor new starting point, unit dimensionless, K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, 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 S114, the computing method of the second positive phase and the second antiphase are the results calculated based on quadrature downconvert and digital filtering.Described digital filtering is made up of 6 grades of rectangular window arithmetic mean filter of 2 kinds of filtering parameters.

When not considering the mixing interfering frequency of quadrature downconvert, quadrature downconvert is expressed as formula (19), and 6 grades of rectangular window arithmetic mean filter filtering calculation expressions of 2 kinds of filtering parameters are formula (20):

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, K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, Ω is signal frequency ω _iwith reference frequency ω _sfrequency difference, ω _ifor signal frequency, 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.

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; K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, 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 (21):

$\begin{array}{c}{N}_{D1}=\left(\mathrm{int}\right)\left({1.5N}_{2\mathrm{\π}}\right)\\ N_{D2}={2N}_{2\mathrm{\π}}\end{array}---\left(21\right)$

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 (22):

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 S115, the second average initial phase computing method, are expressed as formula (23):

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 S116, cosine function modulation sequence is expressed as formula (24):

Wherein, X _cosn () is cosine function modulation sequence; AK _l(ω _i) be cosine function modulation sequence amplitude, unit v; for cosine function modulation sequence initial phase, K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, 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 S117, sine function modulation sequence is expressed as formula (25):

Wherein, X _sinn () is sine function modulation sequence, AK _l(ω _i) be sine function modulation sequence amplitude, unit v, for cosine function modulation sequence initial phase, K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, 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 S118, in one embodiment, obtain zero initial phase benchmark cosine function modulation sequence, be expressed as formula (26):

$\begin{array}{c}X{0}_{cos}\left(n\right)=X_{cos}(\frac{N-1}{2}+n)={\mathrm{AK}}_L\left({\mathrm{\ω}}_i\right)cos\left({\mathrm{\ω}}_{i}Tn\right)\\ n=0,1,2,3,\mathrm{.....},\frac{N-1}{2}-1\end{array}---\left(26\right)$

Wherein, X0 _cosn () is zero initial phase benchmark cosine function modulation sequence, AK _l(ω _i) be cosine function modulation sequence amplitude, unit v, ω _ifor signal frequency, K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, T is sampling interval duration, and n is series of discrete number, and N is predetermined sequence length.

In one embodiment, obtain zero initial phase reference sinusoidal FUNCTION MODULATION sequence, be expressed as formula (27):

$\begin{array}{c}X{0}_{sin}\left(n\right)=X_{sin}(\frac{N-1}{2}+n)={\mathrm{AK}}_L\left({\mathrm{\ω}}_i\right)sin\left({\mathrm{\ω}}_i{T}_{n}n\right)\\ n=0,1,2,3,\mathrm{.....},\frac{N-1}{2}-1\end{array}---\left(27\right)$

Wherein, X0 _sinn () is zero initial phase reference sinusoidal FUNCTION MODULATION sequence, AK _l(ω _i) be sine function modulation sequence amplitude, unit is v, ω _ifor signal frequency, K _l(ω _i) for comb filtering process is at signal frequency ω _idimensionless amplitude gain, T is sampling interval duration, and n is series of discrete number, and (N-1)/2 are sequence length.Zero initial phase reference point avatars as shown in Figure 4.

For step S119, obtain zero initial phase reference sinusoidal function times frequency sequence, be expressed as formula (28):

$\begin{array}{c}X{02}_{\sin }\left(n\right)=2X{0}_{\cos }\left(n\right)X{0}_{\sin }\left(n\right)\\ ={\[{\mathrm{AK}}_L\left({\mathrm{\ω}}_i\right)\]}^2\sin \left(2{\mathrm{\ω}}_i{T}_{n}n\right)\\ n=0,1,2,3,\mathrm{.....},\frac{N-1}{2}\end{array}---\left(28\right)$

Wherein, X02 _sinn () is zero initial phase reference sinusoidal function times frequency sequence, (N-1)/2 are sequence length.

For step S120, in one embodiment, obtain the real sequence of mixing frequently and the empty sequence of mixing frequently, be expressed as formula (29):

$\begin{array}{c}R\left(n\right)=X{02}_{\sin }\left(n\right)\cos \left(2{\mathrm{\ω}}_{s}Tn\right)=\frac{U}{2}\sin \left(2\mathrm{\Ω}Tn\right)+\frac{U}{2}\sin \[2\left({\mathrm{\ω}}_i+{\mathrm{\ω}}_s\right)Tn\]\\ I\left(n\right)=X{02}_{\sin }\left(n\right)\sin \left(2{\mathrm{\ω}}_{s}Tn\right)=\frac{U}{2}\cos \left(2\mathrm{\Ω}Tn\right)-\frac{U}{2}\cos \[2\left({\mathrm{\ω}}_i+{\mathrm{\ω}}_s\right)Tn\]\\ U={\[{\mathrm{AK}}_L\left({\mathrm{\ω}}_i\right)\]}^2\\ 2\mathrm{\Ω}=2{\mathrm{\ω}}_i-2{\mathrm{\ω}}_s\\ n=0,1,2,\mathrm{....},\frac{N-1}{2}-1\end{array}---\left(29\right)$

Wherein, R (n) is the real sequence of mixing frequently, and I (n) is the empty sequence of mixing frequently, X02 _sinn () is zero initial phase reference sinusoidal function times frequency sequence, cos (2 ω _stn) be the discrete cosine function of 2 times of reference frequencies, sin (2 ω _stn) be the discrete sine function of 2 times of reference frequencies, U is public amplitude, unit v ², 2 Ω are signal 2 times of signal frequency 2 ω _iwith 2 times of reference frequency 2 ω _sfrequency difference, T is sampling interval duration, and n is series of discrete number, and 0.5 (N-1) is mixing sequence length.Its middle frequency difference 2 Ω part is useful component, frequency 2 (ω _i+ω _s) be partly mixing interference component.

For step S121, the filtering progression of digital filtering is set, in one embodiment, digital filtering can be carried out to described real mixing sequence frequently and the described empty sequence of mixing frequently respectively by rectangular window arithmetic mean filtering algorithm.

In one embodiment, the filtering progression of digital filtering can be set to 5 etc., and digital filter parameters is 1 times of unit periodic sequence length, and object carries out degree of depth suppression to subharmonic mixing interfering frequency.Do not consider mixing interfering frequency, the formula that is expressed as (30) of real filtered sequence and imaginary frequency filtering sequence frequently:

Wherein, R _dn () is real filtered sequence frequently; I _dn () is imaginary frequency filtering sequence; R (n) is the real sequence of mixing frequently; I (n) is the empty sequence of mixing frequently; U is public amplitude, unit v ²; N _dfor the filtering parameter of rectangular window arithmetic mean filtering algorithm, namely to N _dindividual continuous discrete value is added, and then gets its arithmetic mean and exports as this filter value; T is sampling interval duration; N _{2 π}for unit periodic sequence length; K _d(2 Ω) for digital filtering is in the amplitude gain of frequency difference 2 Ω, unit dimensionless; α (2 Ω) is for digital filtering is in the phase shift of frequency difference 2 Ω; M is digital filtering output sequence length; 0.5 (N-1) is digital filtering list entries length; N is predetermined sequence length.

For step S122, in one embodiment, described digital filtering output sequence length is integration lengths, obtains real integrated value frequently and empty integrated value frequently, is expressed as formula (31):

$\begin{array}{c}{R}_D=\frac{1}{M}\underset{n}{\overset{M-1}{\Σ}}{R}_D\left(n\right)=\frac{U}{2}{\[\frac{\sin \left({\mathrm{\ΩTN}}_D\right)}{{\mathrm{\ΩTN}}_D}\]}^5\[\frac{\sin \left(\mathrm{\Ω}TM\right)}{\mathrm{\Ω}TM}\]\sin \[\mathrm{\Ω}T\left(5N_D+M\right)\]\\ I_D=\frac{1}{M}\underset{n}{\overset{M-1}{\Σ}}{I}_D\left(n\right)=\frac{U}{2}{\[\frac{\sin \left({\mathrm{\ΩTN}}_D\right)}{{\mathrm{\ΩTN}}_D}\]}^5\[\frac{\sin \left(\mathrm{\Ω}TM\right)}{\mathrm{\Ω}TM}\]\cos \[\mathrm{\Ω}T\left(5N_D+M\right)\]\\ M=\frac{N-1}{2}-5N_D\\ n=0,1,2,3,\mathrm{....},M-1\end{array}---\left(31\right)$

Wherein, R _dfor real integrated value frequently; I _dfor void integrated value frequently; R _dn () is real filtered sequence frequently; I _dn () is imaginary frequency filtering sequence; T is sampling interval duration, and M is integration lengths; N _dfor the filtering parameter of rectangular window arithmetic mean filtering algorithm; 0.5 (N-1) is digital filtering list entries length; N is predetermined sequence length.

For step S123, in one embodiment, obtain the phase place of zero initial phase reference sinusoidal FUNCTION MODULATION sequence, be expressed as formula (32):

$PH=arctan\left(\frac{R_D}{I_D}\right)=\mathrm{\Ω}T(5N_D+M)---\left(32\right)$

Wherein, PH is the phase place of zero initial phase reference sinusoidal function times frequency sequence, I _dfor void integrated value frequently, R _dfor real integrated value frequently, M is integration lengths; N _dfor the filtering parameter of rectangular window arithmetic mean filtering algorithm.

In one embodiment, according to the phase place of zero initial phase reference sinusoidal function times frequency sequence, obtain frequency power signal, be expressed as formula (33):

${\mathrm{\ω}}_i=\frac{PH}{T(5N_D+M)}+{\mathrm{\ω}}_s---\left(33\right)$

Wherein, ω _ifor the frequency of electric power signal, PH is the phase place of zero initial phase reference sinusoidal function times frequency sequence, and T is sampling interval duration, and M is integration lengths, N _dfor the filtering parameter of rectangular window arithmetic mean filtering algorithm, ω _sfor reference frequency.

Based on same inventive concept, the present invention also provides a kind of frequency measuring system based on zero initial phase reference sinusoidal function times frequency sequence, is described in detail embodiments of systems of the invention below in conjunction with accompanying drawing.

As shown in Figure 5, a kind of frequency measuring system based on zero initial phase reference sinusoidal function times frequency sequence, 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;

Preprocessing sequence length determination modul 105, for being multiplied with described unit period sequence length by described default integer signal period number, obtains preprocessing sequence length;

Preprocessing sequence acquisition module 106, for according to described preprocessing sequence length, obtains preprocessing sequence from the preliminary sequence of described electric power signal;

Comb filtering sequence determination module 107, for carrying out comb filtering process to described preprocessing sequence, obtain comb filtering sequence, wherein comb filtering sequence length is the residue length of described preprocessing sequence after carrying out comb filtering process;

Predetermined sequence length determination modul 108, for determining the ratio integer of described comb filtering sequence length and described unit period sequence length, predetermined sequence length is obtained according to described ratio integer and described unit period sequence length, wherein said ratio integer is odd number, and described predetermined sequence length is odd number;

First ray acquisition module 109, for according to described predetermined sequence length and default starting point, obtains the first forward sequence from described comb filtering sequence, obtains the first anti-pleat sequence according to described first forward sequence;

First positive and negative phase determination module 110, 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 111, for obtaining the first average initial phase according to described first positive phase and described first antiphase;

New starting point determination module 112, 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 113, for according to described predetermined sequence length and described new starting point, obtains the second forward sequence from described comb filtering sequence, obtains the second anti-pleat sequence according to the second forward sequence;

Second positive and negative phase determination module 114, 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 115, for obtaining the second average initial phase according to described second positive phase and described second antiphase;

Cosine function modulation sequence determination module 116, 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 117, 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 118, 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;

Zero initial phase reference sinusoidal function times frequency sequence determination sequence 119, after being multiplied with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence by described zero initial phase benchmark cosine function modulation sequence, being multiplied by 2 again, obtaining zero initial phase reference sinusoidal function times frequency sequence;

Mixing sequence determination module 120, to be multiplied with the discrete sine function of 2 times of reference frequencies for being multiplied with the discrete cosine function of 2 times of reference frequencies respectively by described zero initial phase reference sinusoidal function times frequency sequence, obtains the real sequence of mixing frequently and the empty sequence of mixing frequently;

Filtered sequence determination module 121, for carrying out digital filtering to described real mixing sequence frequently and the described empty sequence of mixing frequently respectively, obtains real filtered sequence and imaginary frequency filtering sequence frequently;

Integrated value determination module 122, for carrying out integration to described real filtered sequence and described imaginary frequency filtering sequence frequently respectively, obtains real integrated value frequently and empty integrated value frequently;

Frequency power signal determination module 123, for according to described real integrated value frequently and empty integrated value frequently, obtains the phase place of zero initial phase reference sinusoidal function times frequency sequence, obtains the frequency of electric power signal according to described phase place.

In one embodiment, described mixing sequence determination module 120 can according to expression formula R (n)=X02 _sin(n) cos (2 ω _stn) real mixing sequence R frequently (n) is obtained, wherein, X02 _sinn () is zero initial phase reference sinusoidal function times frequency sequence, cos (2 ω _stn) be the discrete cosine function of 2 times of reference frequencies, ω _sfor reference frequency, T is sampling interval duration, and n is series of discrete number,

Described mixing sequence determination module 120 can according to expression formula I (n)=X02 _sin(n) sin (2 ω _stn) empty mixing sequence I frequently (n) is obtained, wherein, X02 _sinn () is zero initial phase reference sinusoidal function times frequency sequence, sin (2 ω _stn) be the discrete sine function of 2 times of reference frequencies, ω _sfor reference frequency, T is sampling interval duration, and n is series of discrete number, $n=0,1,2,\mathrm{.....},\frac{N-1}{2}-1.$

In one embodiment, described filtered sequence determination module 121 can carry out digital filtering to described real mixing sequence frequently and the described empty sequence of mixing frequently respectively by rectangular window arithmetic mean filtering algorithm.

In one embodiment, described frequency power signal determination module 123 can according to expression formula obtain the phase place PH of zero initial phase reference sinusoidal function times frequency sequence, wherein, R _dfor real integrated value frequently, I _dfor void integrated value frequently.

In one embodiment, described frequency power signal determination module 123 can according to expression formula obtain the frequencies omega of electric power signal _i, wherein, PH is the phase place of zero initial phase reference sinusoidal function times frequency sequence, and T is sampling interval duration, and M is integration lengths, N _dfor the filtering parameter of rectangular window arithmetic mean filtering algorithm, ω _sfor reference frequency.

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., based on a frequency measurement method for zero initial phase reference sinusoidal function times frequency 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;

Described default integer signal period number is multiplied with described unit period sequence length, obtains preprocessing sequence length;

According to described preprocessing sequence length, from the preliminary sequence of described electric power signal, obtain preprocessing sequence;

Carry out comb filtering process to described preprocessing sequence, obtain comb filtering sequence, wherein comb filtering sequence length is the residue length of described preprocessing sequence after carrying out comb filtering process;

Determine the ratio integer of described comb filtering sequence length and described unit period sequence length, obtain predetermined sequence length according to described ratio integer and described unit period sequence length, wherein said ratio integer is odd number, and described predetermined sequence length is odd number;

According to described predetermined sequence length and default starting point, from described comb filtering 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 comb filtering 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;

Be multiplied by 2 again after being multiplied with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence by described zero initial phase benchmark cosine function modulation sequence, obtain zero initial phase reference sinusoidal function times frequency sequence;

Described zero initial phase reference sinusoidal function times frequency sequence is multiplied with the discrete cosine function of 2 times of reference frequencies respectively and is multiplied with the discrete sine function of 2 times of reference frequencies, obtain the real sequence of mixing frequently and the empty sequence of mixing frequently;

Respectively digital filtering is carried out to described real mixing sequence frequently and the described empty sequence of mixing frequently, obtain real filtered sequence and imaginary frequency filtering sequence frequently;

Respectively integration is carried out to described real filtered sequence and described imaginary frequency filtering sequence frequently, obtain real integrated value frequently and empty integrated value frequently;

According to described real integrated value frequently and empty integrated value frequently, obtain the phase place of zero initial phase reference sinusoidal function times frequency sequence, obtain the frequency of electric power signal according to described phase place.

2. the frequency measurement method based on zero initial phase reference sinusoidal function times frequency sequence according to claim 1, is characterized in that, according to expression formula obtain the phase place PH of zero initial phase reference sinusoidal function times frequency sequence, wherein, R _dfor real integrated value frequently, I _dfor void integrated value frequently.

3. the frequency measurement method based on zero initial phase reference sinusoidal function times frequency sequence according to claim 1, it is characterized in that, respectively digital filtering is carried out to described real mixing sequence frequently and the described empty sequence of mixing frequently by rectangular window arithmetic mean filtering algorithm.

4. the frequency measurement method based on zero initial phase reference sinusoidal function times frequency sequence according to claim 3, is characterized in that, according to expression formula obtain the frequencies omega of electric power signal _i, wherein, PH is the phase place of zero initial phase reference sinusoidal function times frequency sequence, and T is sampling interval duration, and M is integration lengths, N _dfor the filtering parameter of rectangular window arithmetic mean filtering algorithm, ω _sfor reference frequency.

5. the frequency measurement method based on zero initial phase reference sinusoidal function times frequency sequence according to Claims 1-4 any one, is characterized in that:

According to expression formula R (n)=X02 _sin(n) cos (2 ω _stn) real mixing sequence R frequently (n) is obtained, wherein, X02 _sinn () is zero initial phase reference sinusoidal function times frequency sequence, cos (2 ω _stn) be the discrete cosine function of 2 times of reference frequencies, ω _sfor reference frequency, T is sampling interval duration, and n is series of discrete number,

According to expression formula I (n)=X02 _sin(n) sin (2 ω _stn) empty mixing sequence I frequently (n) is obtained, wherein, X02 _sinn () is zero initial phase reference sinusoidal function times frequency sequence, sin (2 ω _stn) be the discrete sine function of 2 times of reference frequencies, ω _sfor reference frequency, T is sampling interval duration, and n is series of discrete number,

6., based on a frequency measuring system for zero initial phase reference sinusoidal function times frequency 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;

Preprocessing sequence length determination modul, for being multiplied with described unit period sequence length by described default integer signal period number, obtains preprocessing sequence length;

Preprocessing sequence acquisition module, for according to described preprocessing sequence length, obtains preprocessing sequence from the preliminary sequence of described electric power signal;

Comb filtering sequence determination module, for carrying out comb filtering process to described preprocessing sequence, obtain comb filtering sequence, wherein comb filtering sequence length is the residue length of described preprocessing sequence after carrying out comb filtering process;

Predetermined sequence length determination modul, for determining the ratio integer of described comb filtering sequence length and described unit period sequence length, predetermined sequence length is obtained according to described ratio integer and described unit period sequence length, wherein said ratio integer is odd number, and described 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 comb filtering 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 comb filtering 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;

Zero initial phase reference sinusoidal function times frequency sequence determination sequence, is multiplied by 2 again, obtains zero initial phase reference sinusoidal function times frequency sequence after being multiplied with described zero initial phase reference sinusoidal FUNCTION MODULATION sequence by described zero initial phase benchmark cosine function modulation sequence;

Mixing sequence determination module, to be multiplied with the discrete sine function of 2 times of reference frequencies for being multiplied with the discrete cosine function of 2 times of reference frequencies respectively by described zero initial phase reference sinusoidal function times frequency sequence, obtains the real sequence of mixing frequently and the empty sequence of mixing frequently;

Filtered sequence determination module, for carrying out digital filtering to described real mixing sequence frequently and the described empty sequence of mixing frequently respectively, obtains real filtered sequence and imaginary frequency filtering sequence frequently;

Integrated value determination module, for carrying out integration to described real filtered sequence and described imaginary frequency filtering sequence frequently respectively, obtains real integrated value frequently and empty integrated value frequently;

Frequency power signal determination module, for according to described real integrated value frequently and empty integrated value frequently, obtains the phase place of zero initial phase reference sinusoidal function times frequency sequence, obtains the frequency of electric power signal according to described phase place.

7. the frequency measuring system based on zero initial phase reference sinusoidal function times frequency sequence according to claim 6, it is characterized in that, described frequency power signal determination module is according to expression formula obtain the phase place PH of zero initial phase reference sinusoidal function times frequency sequence, wherein, R _dfor real integrated value frequently, I _dfor void integrated value frequently.

8. the frequency measuring system based on zero initial phase reference sinusoidal function times frequency sequence according to claim 6, it is characterized in that, described filtered sequence determination module carries out digital filtering to described real mixing sequence frequently and the described empty sequence of mixing frequently respectively by rectangular window arithmetic mean filtering algorithm.

9. the frequency measuring system based on zero initial phase reference sinusoidal function times frequency sequence according to claim 8, it is characterized in that, described frequency power signal determination module is according to expression formula obtain the frequencies omega of electric power signal _i, wherein, PH is the phase place of zero initial phase reference sinusoidal function times frequency sequence, and T is sampling interval duration, and M is integration lengths, N _dfor the filtering parameter of rectangular window arithmetic mean filtering algorithm, ω _sfor reference frequency.

10. the frequency measuring system based on zero initial phase reference sinusoidal function times frequency sequence according to claim 6 to 9 any one, is characterized in that:

Described mixing sequence determination module is according to expression formula R (n)=X02 _sin(n) cos (2 ω _stn) real mixing sequence R frequently (n) is obtained, wherein, X02 _sinn () is zero initial phase reference sinusoidal function times frequency sequence, cos (2 ω _stn) be the discrete cosine function of 2 times of reference frequencies, ω _sfor reference frequency, T is sampling interval duration, and n is series of discrete number, $n=0,1,2,\mathrm{.....},\frac{N-1}{2}-1;$

Described mixing sequence determination module is according to expression formula I (n)=X02 _sin(n) sin (2 ω _stn) empty mixing sequence I frequently (n) is obtained, wherein, X02 _sinn () is zero initial phase reference sinusoidal function times frequency sequence, sin (2 ω _stn) be the discrete sine function of 2 times of reference frequencies, ω _sfor reference frequency, T is sampling interval duration, and n is series of discrete number, $n=0,1,2,\mathrm{.....},\frac{N-1}{2}-1.$