CN103547328B - Harmonic detecting method and relevant apparatus - Google Patents

Abstract

The invention discloses a kind of harmonic detecting method and relevant apparatus.Wherein, a kind of harmonic detecting method comprises: electric signal of sampling from power circuit is to obtain the electrical signal sequence of N point; The Real Fast Fourier Transform RFFT computing electrical signal sequence of N point being carried out N point obtains the first sequence of complex numbers; Harmonic wave extraction process is carried out to the first sequence of complex numbers and obtains the second sequence of complex numbers; Actual situation is carried out to the second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers; RFFT computing is carried out to the 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; 4th sequence of complex numbers is carried out actual situation and combine process to obtain N point harmonic sequence.The advantageous of the embodiment of the present invention can take into account storage space and computing time when at harmonic detecting.

Description

Harmonic detecting method and relevant apparatus

Technical field

The present invention relates to electronic technology field, be specifically related to harmonic detecting method and relevant apparatus.

Background technology

At present, the various power electronic equipment of widespread use and nonlinear load in electric system, make to create a large amount of harmonic wave.Harmonic wave not only can constitute a threat to the safe operation of electric system itself, brings impact greatly and harm also may to the electric circumstance of surrounding.

Active Power Filter-APF (APF, ActivePowerFilter) is a kind of power electronic equipment for dynamic harmonic wave and compensating reactive power.Static reacance generator (SVG, StaticVarGenerator) is one of main device in flexible AC transmitting system (FACTS, FlexibleACTransmissionSystem).APF can compensate humorous the idle of change that involve that size and frequency all change, and the detection of APF to harmonic signal is the key ensureing its compensation performance.SVG can dynamic compensation idle, also can compensation harmonic, SVG represents the new developing direction of power system reactive power compensation technology, and the detection of same harmonic signal is the key ensureing SVG harmonic compensation performance.

Harmonic signal in electric system typically refers to current harmonics and voltage harmonic.Wherein, when APF/SVG adopts parallel way to dispose, usually detect and administer current harmonics; When APF/SVG adopts series system to dispose, usually detect and administer voltage harmonic.Existing harmonic detecting technique is difficult to take into account storage space and computing time etc.

Summary of the invention

The embodiment of the present invention provides a kind of harmonic detecting method and relevant apparatus, can take into account storage space and computing time to harmonic detecting.

The embodiment of the present invention provides a kind of harmonic detecting method on the one hand, comprising: electric signal of sampling from power circuit is to obtain the electrical signal sequence of N point, the Real Fast Fourier Transform RFFT computing that the electrical signal sequence of described N point carries out N point is obtained the first sequence of complex numbers, harmonic wave extraction process is carried out to described first sequence of complex numbers and obtains the second sequence of complex numbers, actual situation is carried out to described second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers, carry out actual situation to described second sequence of complex numbers to comprise in conjunction with process: in described second sequence of complex numbers comprising multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, wherein, described 3rd real equals imaginary part coefficient and the real part sum of corresponding second plural number, the imaginary part coefficient of described 3rd plural number equals the difference of corresponding second real and imaginary part coefficient, Real Fast Fourier Transform RFFT computing is carried out to described 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers, and described 4th sequence of complex numbers is carried out actual situation combination process to obtain N point harmonic sequence, carry out actual situation to described 4th sequence of complex numbers to comprise in conjunction with process: in described 4th sequence of complex numbers comprising multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, wherein, described 6th real equals imaginary part coefficient and the real part sum of corresponding 4th plural number, the imaginary part coefficient of described 6th plural number equals the difference of corresponding 4th real and imaginary part coefficient.

Optionally, described electric signal of sampling from power circuit comprises with the step of the electrical signal sequence obtaining N point: within a signal primitive period, from the sampling electric signal of power circuit equal intervals to obtain the electrical signal sequence of N point.

Optionally, describedly the step that harmonic wave extraction process obtains the second sequence of complex numbers is carried out to described first sequence of complex numbers comprise: remove fundametal compoment in described first sequence of complex numbers to obtain described second sequence of complex numbers;

Or,

Make the harmonic component in described first sequence of complex numbers be zero to obtain the 5th sequence of complex numbers, then deduct described 5th sequence of complex numbers to obtain described second sequence of complex numbers with described first sequence of complex numbers again.

Optionally, the step that the Real Fast Fourier Transform RFFT computing that the described electrical signal sequence by described N point carries out N point obtains the first sequence of complex numbers comprises: by the electrical signal sequence of described N point divided by after described N, then the RFFT computing carrying out N point obtains the first sequence of complex numbers;

Or,

Describedly the step that harmonic wave extraction process obtains the second sequence of complex numbers carried out to described first sequence of complex numbers comprise: to described first sequence of complex numbers divided by described N after carry out harmonic wave extraction process again and obtain the second sequence of complex numbers;

Or,

Described to described second sequence of complex numbers carry out actual situation combine process comprise with the step obtaining the 3rd sequence of complex numbers: to described second sequence of complex numbers divided by described N after, then carry out actual situation combine process to obtain the 3rd sequence of complex numbers;

Or, describedly the step that RFFT computing obtains the 4th sequence of complex numbers carried out to described 3rd sequence of complex numbers comprise: to described 3rd sequence of complex numbers divided by described N after carry out RFFT computing again and obtain the 4th sequence of complex numbers;

Or,

Described described 4th sequence of complex numbers is carried out actual situation combine process comprise with the step obtaining N point harmonic sequence: will described 4th sequence of complex numbers divided by described N after, then carry out actual situation combination process to obtain N point harmonic sequence;

Or,

Described harmonic detecting method also comprises: by the described N point harmonic sequence that obtains divided by described N.

The embodiment of the present invention also provides a kind of harmonic measurement device on the other hand, can comprise: sampling unit, for electric signal of sampling from power circuit to obtain the electrical signal sequence of N point, one RFFT arithmetic element, the Real Fast Fourier Transform RFFT computing that the electrical signal sequence for the N point obtained by described sampling unit carries out N point obtains the first sequence of complex numbers, harmonic extraction unit, the first sequence of complex numbers for obtaining a described RFFT arithmetic element carries out harmonic wave extraction process and obtains the second sequence of complex numbers, actual situation is in conjunction with processing unit, the second sequence of complex numbers for obtaining described harmonic extraction unit carries out actual situation and combines process to obtain the 3rd sequence of complex numbers, concrete, what described actual situation obtained in described harmonic extraction unit in conjunction with processing unit comprises in described second sequence of complex numbers of multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, wherein, described 3rd real equals imaginary part coefficient and the real part sum of corresponding second plural number, the imaginary part coefficient of described 3rd plural number equals the difference of corresponding second real and imaginary part coefficient, to obtain the 3rd sequence of complex numbers comprising multiple 3rd plural number, 2nd RFFT arithmetic element, obtains the 4th sequence of complex numbers for carrying out RFFT computing to described actual situation in conjunction with the 3rd sequence of complex numbers that processing unit obtains, and described actual situation in conjunction with processing unit also for, the 4th sequence of complex numbers that described 2nd RFFT arithmetic element obtains is carried out actual situation and combine process to obtain N point harmonic sequence, concrete, what described actual situation obtained in described 2nd RFFT arithmetic element in conjunction with processing unit comprises in the 4th sequence of complex numbers of multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, wherein, described 6th real equals imaginary part coefficient and the real part sum of corresponding 4th plural number, the imaginary part coefficient of described 6th plural number equals the difference of corresponding 4th real and imaginary part coefficient, to obtain the N point harmonic sequence comprising multiple 6th plural number.

Optionally, a described RFFT arithmetic element specifically for, the electrical signal sequence of the N point obtained by described sampling unit is divided by after described N, then the RFFT computing carrying out N point obtains the first sequence of complex numbers;

Or,

Described harmonic extraction unit specifically for, described first sequence of complex numbers that RFFT computing obtains is carried out divided by after described N to a described RFFT arithmetic element, then carries out harmonic wave extraction process and obtain the second sequence of complex numbers;

Or,

Described actual situation in conjunction with processing unit specifically for, described second sequence of complex numbers obtained described harmonic extraction unit divided by after described N, then carry out actual situation and combine process to obtain the 3rd sequence of complex numbers;

Or,

Described 2nd RFFT arithmetic element divided by after described N specifically for, the 3rd sequence of complex numbers obtained in conjunction with processing unit described actual situation, then is carried out RFFT computing and is obtained the 4th sequence of complex numbers;

Or,

Described actual situation in conjunction with processing unit also for, described 4th sequence of complex numbers that described 2nd RFFT arithmetic element is obtained divided by after described N, then carry out actual situation and combine process to obtain N point harmonic sequence;

Or,

Described actual situation is also carried out actual situation for, described 4th sequence of complex numbers described 2nd RFFT arithmetic element obtained in conjunction with processing unit and is combined process to obtain N point harmonic sequence, is exported by described N point harmonic sequence divided by after described N.

The another aspect of the embodiment of the present invention also provides a kind of Harmonics elimination equipment, comprising:

Harmonic measurement device, for electric signal of sampling from power circuit to obtain the electrical signal sequence of N point; The Real Fast Fourier Transform RFFT computing that the electrical signal sequence of described N point carries out N point is obtained the first sequence of complex numbers; Harmonic wave extraction process is carried out to described first sequence of complex numbers and obtains the second sequence of complex numbers; Actual situation is carried out to described second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers; RFFT computing is carried out to described 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; And described 4th sequence of complex numbers is carried out actual situation combination process to obtain N point harmonic sequence and to export;

Electric signal feedback assembly, the described N point harmonic sequence for exporting based on described harmonic measurement device generates and compensates electric signal, and the described compensation electric signal generated is fed back to described power circuit to eliminate the harmonic wave produced in described power circuit;

Wherein, described harmonic measurement device carries out actual situation to described second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers, comprise: in described second sequence of complex numbers comprising multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, wherein, described 3rd real equals imaginary part coefficient and the real part sum of corresponding second plural number, the imaginary part coefficient of described 3rd plural number equals the difference of corresponding second real and imaginary part coefficient,

Described harmonic measurement device carries out actual situation to described 4th sequence of complex numbers and combines process to obtain N point harmonic sequence, comprise: in described 4th sequence of complex numbers comprising multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, wherein, described 6th real equals imaginary part coefficient and the real part sum of corresponding 4th plural number, the imaginary part coefficient of described 6th plural number equals the difference of corresponding 4th real and imaginary part coefficient.

Therefore in the technical scheme that the embodiment of the present invention provides, the RFFT computing that electric signal of sampling from power circuit carries out N point with the electrical signal sequence obtaining N point obtains the first sequence of complex numbers; Harmonic wave extraction process is carried out to the first sequence of complex numbers and obtains the second sequence of complex numbers; Actual situation is carried out to the second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers; RFFT computing is carried out to the 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; 4th sequence of complex numbers is carried out actual situation and combine process to obtain N point harmonic sequence.The technical program without the need to carrying out conjugate operation before and after RFFT, also without the need to data extraction operation, and only need carry out twice actual situation combination process operation, namely simply reducing is added, so in terms of existing technologies, comparatively save computing time, and carry out computing due to RFFT code can be made full use of, so also can code space be saved.

Further, do not need increase additional storage space, can code space, number of memory cells and computing time complex optimum.

Term " first ", " second ", " the 3rd " " 4th " etc. (if existence) in instructions of the present invention and claims and above-mentioned accompanying drawing are for distinguishing similar object, and need not be used for describing specific order or precedence.Should be appreciated that the data used like this can be exchanged in the appropriate case, so as embodiments of the invention described herein such as can with except here diagram or describe those except order implement.In addition, term " comprises " and " having " and their any distortion, intention is to cover not exclusive comprising, such as, contain those steps or unit that the process of series of steps or unit, method, system, product or equipment is not necessarily limited to clearly list, but can comprise clearly do not list or for intrinsic other step of these processes, method, product or equipment or unit.

Harmonic signal sensing range of the present invention comprises the detection to harmonic voltage and/or harmonic current.

Harmonic signal detection method mainly contains: analog bandpass filtering device detection method, detection method, fast fourier transform (FFT, FastFourierTransformation) detection method etc. based on instantaneous reactive power theory.Detection method based on simulation circulation wave filter can only detect the harmonic wave within the scope of fixed frequency, cannot carry out real-Time Compensation, and easily cause resonance to the harmonic wave of change; Quickly diaphragm filter and the harmonic wave that can detect based on the detection method of instantaneous reactive power theory in broad frequency domain, therefore, be widely used in electric system.Detection method based on instantaneous reactive has original advantage idle with harmonic wave entire compensation and quick responder's mask, and FFT detection method is being carried out in signal spectrum labor and data display, then that the former is irreplaceable, especially in harmonic content analysis with carry out in separate compensation with the obvious advantage to indivedual frequency spectrum.Consider the duality of FFT and IFFT, to those used FFT detection method carry out harmonic content analysis and display device in (as part APF and SVG), directly can call existing code to carry out inverse transformation and obtain harmonic wave instruction, make FFT these occasions application advantageously.Based on FFT harmonic wave extracting method denounce be to calculate more complicated, real-time poor, calculate time committed memory more.

When needing one in APF/SVG or compensate several specific subharmonic simultaneously, it is essential that FFT calculates, HARMONIC SIGNAL EXTRACTION FROM based on FFT inverse transformation principle is more because of committed memory, the sequential operation time is longer, applies and be obstructed in extensive process in real time.

Some improved Harmonic Current Detecting Methods based on FFT are analyzed as follows:

(1) FFT is adopted to calculate harmonic sequence, although positive inverse transformation can share same FFT program segment, cost is reduction of direct transform efficiency, adds 1 times of storage space, to inverse transformation method, also need extra conjugation (or sequence) operation and data extraction operation.

(2) adopt real number and plural FFT to combine and calculate harmonic sequence, direct transform operation time and storage space can obtain optimum, although a kind of method improves the efficiency of direct transform comparatively, these class methods sacrifice code and share, and add the complicacy of program.

(3) Real Fast Fourier Transform (RFFT is adopted, RealnumberFFT) harmonic sequence is calculated, though this method can code reuse, but extra increase by 1 times of storage space, need twice real empty lock out operation, operand also increases greatly, have impact on the arithmetic speed of processor.Visible above-mentioned several method respectively has relative merits, does not have a kind ofly can take into account code reuse, storage space and the combination property of computing time.

An embodiment of harmonic detecting method of the present invention, can comprise: electric signal of sampling from power circuit is to obtain the electrical signal sequence of N point; The Real Fast Fourier Transform RFFT computing electrical signal sequence of this N point being carried out N point obtains the first sequence of complex numbers; Harmonic wave extraction process is carried out to the first sequence of complex numbers and obtains the second sequence of complex numbers; Actual situation is carried out to the second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers; RFFT computing is carried out to the 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; 4th sequence of complex numbers is carried out actual situation and combine process to obtain N point harmonic sequence.

Refer to Fig. 1, Figure 1 shows that and can comprise following content by a kind of harmonic detecting method that the embodiment of the present invention provides:

Step 101, electric signal of sampling from power circuit are to obtain the electrical signal sequence of N point.

In some embodiments of the invention, can within a signal primitive period, from the sampling electric signal of power circuit equal intervals or unequal interval to obtain the electrical signal sequence of N point.For example, such as can from three-phase power circuit, to extract in the signal primitive period at equal intervals or the three-phase current signal of unequal interval (or three-phase voltage signal), to obtain N point current signal sequence (or N point voltage burst) corresponding to every phase current.

Step 102, the RFFT computing electrical signal sequence of N point being carried out N point obtain the first sequence of complex numbers.

Wherein, the first sequence of complex numbers comprises multiple first plural number.

Refer to Fig. 2, Figure 2 shows that the storage schematic diagram of the calculating data that the embodiment of the present invention provides.As shown in Figure 2, the electrical signal sequence of N point is expressed as R ₀~ R _n-1, suppose the electrical signal sequence (R with N number of cell stores N point ₀~ R _n-1), by the electrical signal sequence (R of N point ₀~ R _n-1) the RFFT computing of carrying out N point obtains the first sequence of complex numbers, by DC component in the first sequence of complex numbers and data corresponding to nyquist frequency point (as R ₀and R _n/2) be stored in 2 storage unit, also can by wherein (the N-2)/2 plural number (R in N-2 plural number remaining in the first sequence of complex numbers ₁~ R _n/2-1) real part be stored in (N-2)/2 storage unit, and (N-2)/2 plural imaginary part coefficient storage will be somebody's turn to do in (N-2)/2 storage unit, because except DC component and data corresponding to nyquist frequency point are (as R in the first sequence of complex numbers ₀and R _n/2) outside two parts plural number (R ₁~ R _n/2-1) and (R _n/2+1~ R _n-1) real part and imaginary part coefficient there is conjugate symmetry, therefore utilize the plural number (R of storage ₁~ R _n/2-1) plural number that the first sequence of complex numbers do not store can be recovered, like this can larger province storage space, certainly, (the R in the first sequence of complex numbers also can be stored _n/2+1~ R _n-1) part, do not store (the R in the first sequence of complex numbers ₁~ R _n/2-1), and according to (R _n/2+1~ R _n-1) also can recover (R ₁~ R _n/2-1) part.Be appreciated that the plural number in other sequence of complex numbers with conjugate symmetry also can store in this manner.

Please continue see Fig. 1, step 103, harmonic wave extraction process is carried out to the first sequence of complex numbers obtain the second sequence of complex numbers.

In some embodiments of the invention, carry out to the first sequence of complex numbers the step that harmonic wave extraction process obtains the second sequence of complex numbers can comprise: remove fundametal compoment in the first sequence of complex numbers to obtain the second sequence of complex numbers (certainly, yet can remove the harmonic component not needing number of times, namely, only can extract the harmonic component of number of times set by one or several), for example, the fundametal compoment in the first sequence of complex numbers such as can be made to be zero to obtain the second sequence of complex numbers; Or, the harmonic component in the first sequence of complex numbers also can be made to be zero to obtain the 5th sequence of complex numbers, then to deduct the 5th sequence of complex numbers to obtain the second sequence of complex numbers with the first sequence of complex numbers again.

Wherein, the second sequence of complex numbers comprises multiple second plural number.

Step 104, actual situation of carrying out the second sequence of complex numbers combine process to obtain the 3rd sequence of complex numbers.

In some embodiments of the invention, such as in the second sequence of complex numbers comprising multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, and, described 3rd real equals imaginary part coefficient and the real part sum of second plural number corresponding to it, the imaginary part coefficient of described 3rd plural number equals the difference of second real corresponding to it and imaginary part coefficient, so, each second plural number in second sequence of complex numbers except the data corresponding to DC component and nyquist frequency point is done actual situation as above and combine the 3rd sequence of complex numbers that process just can obtain N point, namely the 3rd sequence of complex numbers comprises multiple 3rd plural number, wherein, 3rd sequence of complex numbers of this N point comprises the DC component in the second sequence of complex numbers and the data corresponding to nyquist frequency point, also comprise in the second sequence of complex numbers, each second plural number except the data corresponding to DC component and nyquist frequency point, three plural number corresponding with each second plural number described that the processing mode combined by actual situation is generated.

Step 105, RFFT computing is carried out to the 3rd sequence of complex numbers obtain the 4th sequence of complex numbers.

Wherein, the 4th sequence of complex numbers comprises multiple 4th plural number.

Step 106, actual situation of being carried out by the 4th sequence of complex numbers combine process to obtain N point harmonic sequence.

In some embodiments of the invention, such as, in the 4th sequence of complex numbers comprising multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, described 6th real equals imaginary part coefficient and the real part sum of four plural number corresponding to it, the imaginary part coefficient of described 6th plural number equals the difference of four real corresponding to it and imaginary part coefficient, so, each plural number in 4th sequence of complex numbers is done actual situation as above and combine the N point harmonic sequence that process just can obtain comprising multiple 6th plural number, wherein, this N point harmonic sequence comprises DC component and the data corresponding to nyquist frequency point in above-mentioned 4th sequence of complex numbers, also comprise in above-mentioned 4th sequence of complex numbers, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, six plural number corresponding with each the 4th plural number described that the processing mode combined by actual situation is generated.

Wherein, twice real empty, and to combine the mode of process identical, can code multiplexing, and then be conducive to saving code memory space.The present embodiment scheme is without the need to carrying out conjugate operation, and only need simply add reducing to data, just can under less operand and the prerequisite not increasing additional memory units, realize multiplexing RFFT code and complete Harmonics Calculation, and Output rusults also can not need data to extract the operations such as sequence, may correspond to initial sequence of real numbers completely, be conducive to saving computing time, also can not increase extra code space and storage space.As the occasions such as harmonic amplitude, phase place, total harmonic distortion (THD, totalharmonicdistortion) need be calculated, program's memory space can also be reduced by abundant multiplexing code.

It should be noted that the N in the embodiment of the present invention refers to counting of inverse Fourier transform, the harmonic sequence length namely exported.

In addition, in order to obtain real amplitude, can also reduce to amplitude, namely through the computing (can be described as 1/N operation in embodiments of the present invention) of " divided by N ".

For example, in one embodiment of this invention, the RFFT computing electrical signal sequence of N point being carried out N point in step 102 obtains the first sequence of complex numbers and can comprise following concrete steps: by the electrical signal sequence of N point divided by N after, then the RFFT computing carrying out N point obtains the first sequence of complex numbers.

Or, in another embodiment of the invention, harmonic wave extraction process is carried out to the first sequence of complex numbers obtain the second sequence of complex numbers and can comprise following concrete steps in step 103: to the first sequence of complex numbers divided by N after carry out harmonic wave extraction process again and obtain the second sequence of complex numbers.

Or, in another embodiment of the invention, in step 104 to the second sequence of complex numbers carry out actual situation combine process can comprise following concrete steps to obtain the 3rd sequence of complex numbers: to the second sequence of complex numbers divided by N after, then carry out actual situation combine process to obtain the 3rd sequence of complex numbers.

Or, in another embodiment of the invention, RFFT computing is carried out to the 3rd sequence of complex numbers obtain the 4th sequence of complex numbers and can comprise following concrete steps in step 105: to the 3rd sequence of complex numbers divided by N after carry out RFFT computing again and obtain the 4th sequence of complex numbers.

Or, in another embodiment of the invention, in step 106 will to obtain the 4th sequence of complex numbers carry out actual situation combine process comprise following concrete steps to obtain N point harmonic sequence: to the 4th sequence of complex numbers divided by N after, then carry out actual situation combine process to obtain N point harmonic sequence.

Or, in another embodiment of the invention, also the N obtained some harmonic sequence can be exported divided by after N again.

For the ease of better understanding the embodiment of the present invention, below the foundation of the method provided the embodiment of the present invention is made a setting analysis.

For RFFT, the electrical signal sequence of sampling can be expressed as:

x(n)＝x _R(n),0≤n≤N-1；

Because the imaginary part of electrical signal sequence of sampling is 0, so can draw according to DFT definition and character:

$DFT:X_R\left(k\right)=\underset{n=0}{\overset{N-1}{\Σ}}\[x_R\left(n\right)cos\frac{2\mathrm{\π}kn}{N}+x_I\left(n\right)\sin \frac{2\mathrm{\π}kn}{N}\]=\underset{n=0}{\overset{N-1}{\Σ}}{x}_R\left(n\right)cos\frac{2\mathrm{\π}kn}{N}$

$X_I\left(k\right)=\underset{n=0}{\overset{N-1}{\Σ}}\[x_R\left(n\right)sin\frac{2\mathrm{\π}kn}{N}-x_I\left(n\right)cos\frac{2\mathrm{\π}kn}{N}\]=\underset{n=0}{\overset{N-1}{\Σ}}{x}_R\left(n\right)sin\frac{2\mathrm{\π}kn}{N};$

That is, after RFFT, real part is cosine component, and be real even sequence, imaginary part is sinusoidal component, is real odd sequence.

For inverse fourier transform, list entries is:

X(k)＝X _R(k)+jX _I(k),0≤k≤N-1；

Its inverse transformed result is x (n), and the character according to inverse Fourier transform can obtain:

x(n)＝IFFT(X(k))

＝IFFT(X _R(k)+jX _I(k))

＝IFFT(X _R(k))+j*IFFT(X _I(k))

＝conj(FFT(X _R(k)))+j*conj(FFT(X _I(k)))

＝FFT(X _R(k))+j*(-1)*(FFT(X _I(k))

Can obtain: x (n)=FFT (X _r(k))-j* (FFT (X _i(k)),

Wherein, 0≤k≤N-1;

It should be noted that, eliminate 1/N operation in above formula, consider that 1/N only affects final amplitude, so do not analyze herein, be understandable that, if real amplitude need be obtained, 1/N operation can be carried out to result.

By x (n)=FFT (X _r(k))-j* (FFT (X _i(k)) can find out, still containing two FFT conversion in this result, and each conversion needs N number of data, therefore, also needs this formula x (n)=FFT (X _r(k))-j* (FFT (X _i(k)) be further analyzed, as follows:

Make S (K)=X _r(k)+X _ik (), then at S (K)=X _r(k)+X _ik FFT is asked on the both sides of (), obtain:

S(K)＝X _R(k)+X _I(k)；

Wherein, FFT (X _r(k)) be pure real number, and FFT (X _i(k)) be pure imaginary number.

Therefore, can obtain:

S=FFT (X _r(k))+FFT (X _i(k))=s _r+ j*s _i, wherein, 0≤k≤N-1;

Wherein, s=FFT (X _r(k))+FFT (X _i(k))=s _r+ j*s _i.

So, formula x (n)=FFT (X _r(k))-j* (FFT (X _i(k)) can abbreviation be:

X (n)=s _r+ s _i, wherein, 0≤k≤N-1;

By formula x (n)=s _r+ s _iknown, only need build S (K) and carry out FFT to it, just by formula x (n)=s _r+ s _ireduce initial sequence of real numbers x (n).In fact, when consistent for number of memory cells, need to build S (K) and formula x (n)=s _r+ s _iidentical expression formula, so a program segment can be shared.

As can be seen from Figure 2, typical N point sequence of real numbers is after RFFT conversion, its conjugate symmetry can be utilized only to store the data (i.e. spectrum value) of half, if so N number of point will be calculated, also need to reduce second half data, because the Data Conjugate of second half data and preservation is symmetrical, therefore the building mode of S (K) can be analyzed to:

Obviously, x (n) can adopt said method to realize equally, does not repeat them here.

As from the foregoing, the RFFT computing that electric signal of sampling from power circuit carries out N point with the electrical signal sequence obtaining N point is obtained the first sequence of complex numbers by the present embodiment; Harmonic wave extraction process is carried out to the first sequence of complex numbers and obtains the second sequence of complex numbers; Actual situation is carried out to the second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers; RFFT computing is carried out to the 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; 4th sequence of complex numbers is carried out actual situation and combine process to obtain N point harmonic sequence, this programme without the need to carrying out conjugate operation before and after RFFT, also without the need to data extraction operation, and only need carry out twice actual situation binding operation, namely simply add reducing, so in terms of existing technologies, comparatively save computing time, and carry out computing due to RFFT code can be made full use of, so also can code space be saved.Further, do not need increase additional storage space, can code space, number of memory cells and computing time complex optimum.

For ease of better understanding and implementing embodiment of the present invention such scheme, be also provided for the relevant apparatus implementing such scheme below.

Refer to Fig. 3, the embodiment of the present invention also provides a kind of harmonic measurement device 300, can comprise: sampling unit 301, a RFFT arithmetic element 302, harmonic extraction unit 303, actual situation are in conjunction with processing unit 304 and the 2nd RFFT arithmetic element 305.

Wherein, sampling unit 301, for electric signal of sampling from power circuit to obtain the electrical signal sequence of N point.

In some embodiments of the invention, sampling unit 301 can within a signal primitive period, from the sampling electric signal of power circuit equal intervals or unequal interval to obtain the electrical signal sequence of N point.Such as sampling unit 301 can from three-phase power circuit, to extract in the signal primitive period at equal intervals or the three-phase current signal of unequal interval (or three-phase voltage signal), to obtain the N point current signal sequence (or N point voltage burst) of every phase current.

One RFFT arithmetic element 302, the Real Fast Fourier Transform RFFT computing that the electrical signal sequence for the N point obtained by sampling unit 301 carries out N point obtains the first sequence of complex numbers.Wherein, the first sequence of complex numbers comprises multiple first plural number.

Harmonic extraction unit 303, the first sequence of complex numbers for obtaining a RFFT arithmetic element 302 carries out harmonic wave extraction process and obtains the second sequence of complex numbers.Wherein, the second sequence of complex numbers comprises multiple second plural number.

Actual situation is in conjunction with processing unit 304, and the second sequence of complex numbers for obtaining harmonic extraction unit 303 carries out actual situation and combines process to obtain the 3rd sequence of complex numbers.Wherein, the 3rd sequence of complex numbers comprises multiple 3rd plural number.

2nd RFFT arithmetic element 305, obtains the 4th sequence of complex numbers for carrying out RFFT computing to actual situation in conjunction with the 3rd sequence of complex numbers that processing unit 304 obtains.Wherein, the 4th sequence of complex numbers comprises multiple 4th plural number.

Actual situation is carried out actual situation in conjunction with the 4th sequence of complex numbers of processing unit 303 also for the 2nd RFFT arithmetic element 305 being obtained and is combined process to obtain N point harmonic sequence.

In some embodiments of the invention, actual situation can be specifically in conjunction with processing unit 304, what obtain in harmonic extraction unit 303 comprises in the second sequence of complex numbers of multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, and, described 3rd real equals imaginary part coefficient and the real part sum of second plural number corresponding with it, the imaginary part coefficient of described 3rd plural number equals the difference of second real corresponding to it and imaginary part coefficient, by each second plural number being carried out the process of actual situation combination to obtain the 3rd sequence of complex numbers.

In some embodiments of the invention, actual situation in conjunction with processing unit 304 also specifically for, what obtain for the 2nd RFFT arithmetic element 305 comprises in the 4th sequence of complex numbers of multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, and, described 6th real equals imaginary part coefficient and the real part sum of four plural number corresponding to it, the imaginary part coefficient of described 6th plural number equals the difference of the corresponding with it the 4th multiple real and imaginary part coefficient, by each the 4th plural number being carried out the process of actual situation combination to obtain comprising the N point harmonic sequence of multiple 6th plural number.

Be appreciated that, actual situation comprises the DC component in the second sequence of complex numbers and the data corresponding to nyquist frequency point in conjunction with the 3rd sequence of complex numbers that processing unit 304 obtains, also comprise for each second plural number in the second sequence of complex numbers except the data corresponding to DC component and nyquist frequency point, three plural number corresponding with each second plural number described that the processing mode combined by actual situation is generated.Actual situation comprises the DC component in above-mentioned 4th sequence of complex numbers and the data corresponding to nyquist frequency point in conjunction with the N point harmonic sequence that processing unit 304 obtains, also comprise for each the 4th plural number in above-mentioned 4th sequence of complex numbers except the data corresponding to DC component and nyquist frequency point, six plural number corresponding with each the 4th plural number described that the processing mode combined by actual situation is generated.

It should be noted that the N in the embodiment of the present invention refers to counting of inverse Fourier transform, the harmonic sequence length namely exported.

In addition, in order to obtain real amplitude, can also reduce to amplitude, namely through the computing (can be described as 1/N operation in embodiments of the present invention) of " divided by N ".

In some embodiments of the invention, harmonic extraction unit 303 specifically for, remove fundametal compoment in the first sequence of complex numbers to obtain the second sequence of complex numbers.

In some embodiments of the invention, a RFFT arithmetic element 302 can be specifically for, and the electrical signal sequence of the N point obtained by sampling unit 301 is divided by after N, then the RFFT computing carrying out N point obtains the first sequence of complex numbers.

Or,

Harmonic extraction unit 303 can be specifically for, carries out the first sequence of complex numbers that RFFT computing obtains divided by after N to a RFFT arithmetic element 302, then carry out harmonic wave extraction process and obtain the second sequence of complex numbers.

Or,

Actual situation in conjunction with processing unit 304 specifically for, the second sequence of complex numbers obtained harmonic extraction unit 303 divided by after N, then carry out actual situation and combine process to obtain the 3rd sequence of complex numbers.

Or,

2nd RFFT arithmetic element 305 divided by after N specifically for, the 3rd sequence of complex numbers obtained in conjunction with processing unit 304 actual situation, then is carried out RFFT computing and is obtained the 4th sequence of complex numbers.

Or,

Actual situation in conjunction with processing unit 304 also for, the 4th sequence of complex numbers that the 2nd RFFT arithmetic element 305 is obtained divided by after N, then carry out actual situation and combine process to obtain N point harmonic sequence.

Or,

Actual situation is also carried out actual situation for, the 4th sequence of complex numbers the 2nd RFFT arithmetic element 305 obtained in conjunction with processing unit 304 and is combined process to obtain N point harmonic sequence, is exported by this N point harmonic sequence divided by after N.

Be appreciated that the function of each functional module of the harmonic measurement device 300 of the present embodiment can according to the method specific implementation in said method embodiment, its specific implementation process see the associated description in said method embodiment, can repeat no more herein.The present embodiment harmonic measurement device 300 can be deployed in APF/SVG, to carry out the device of harmonic detecting in APF/SVG.

Refer to Fig. 4, the embodiment of the present invention also provides a kind of Harmonics elimination equipment 400, can comprise: harmonic measurement device 410 and electric signal feedback assembly 420.

Wherein, harmonic measurement device 410, for electric signal of sampling from power circuit to obtain the electrical signal sequence of N point; The RFFT computing that the electrical signal sequence of this N point carries out N point is obtained the first sequence of complex numbers; Harmonic wave extraction process is carried out to the first sequence of complex numbers and obtains the second sequence of complex numbers; Actual situation is carried out to the second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers; RFFT computing is carried out to the 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; 4th sequence of complex numbers is carried out actual situation and combine process to obtain N point harmonic sequence and to export.

Electric signal feedback assembly 420, the N point harmonic sequence for exporting based on harmonic measurement device 410 generates and compensates electric signal, and this compensation electric signal generated is fed back to this power circuit to eliminate the harmonic wave produced in this power circuit.

In some embodiments of the invention, harmonic measurement device 410 can within a signal primitive period, from the sampling electric signal of power circuit equal intervals or unequal interval to obtain the electrical signal sequence of N point.For example, harmonic measurement device 410 such as can from three-phase power circuit, to extract in the signal primitive period at equal intervals or the three-phase current signal of unequal interval (or three-phase voltage signal), to obtain the N point current signal sequence (or N point voltage burst) of every phase current.

In some embodiments of the invention, harmonic measurement device 410 such as can adopt data storage method as shown in Figure 2 to carry out data storage.Such as the electrical signal sequence of N point is expressed as R ₀~ R _n-1, suppose the electrical signal sequence (R with N number of cell stores N point ₀~ R _n-1), by the electrical signal sequence (R of N point ₀~ R _n-1) the RFFT computing of carrying out N point obtains the first sequence of complex numbers, by DC component in the first sequence of complex numbers and data corresponding to nyquist frequency point (as R ₀and R _n/2) be stored in 2 storage unit, also can by wherein (the N-2)/2 plural number (R in N-2 plural number remaining in the first sequence of complex numbers ₁~ R _n/2-1) real part be stored in (N-2)/2 storage unit, and (N-2)/2 plural imaginary part coefficient storage will be somebody's turn to do in (N-2)/2 storage unit, because except DC component and data corresponding to nyquist frequency point are (as R in the first sequence of complex numbers ₀and R _n/2) outside two parts plural number (R ₁~ R _n/2-1) and (R _n/2+1~ R _n-1) real part and imaginary part coefficient there is conjugate symmetry, therefore utilize the plural number (R of storage ₁~ R _n/2-1) plural number that the first sequence of complex numbers do not store can be recovered, like this can larger province storage space, certainly, harmonic measurement device 410 also can store (the R in the first sequence of complex numbers _n/2+1~ R _n-1) part, do not store (the R in the first sequence of complex numbers ₁~ R _n/2-1), and according to (R _n/2+1~ R _n-1) also can recover (R ₁~ R _n/2-1) part.Be appreciated that the plural number in other sequence of complex numbers with conjugate symmetry also can store in this manner.

In some embodiments of the invention, harmonic measurement device 410 carries out harmonic wave extraction process to the first sequence of complex numbers and obtains the second sequence of complex numbers and such as can comprise: the fundametal compoment removed in the first sequence of complex numbers (yet can remove the harmonic component not needing number of times certainly to obtain the second sequence of complex numbers, namely, only can extract the harmonic component of number of times set by one or several), for example, the fundametal compoment in the first sequence of complex numbers such as can be made to be zero to obtain the second sequence of complex numbers; Or, the harmonic component in the first sequence of complex numbers also can be made to be zero to obtain the 5th sequence of complex numbers, then to subtract the 5th sequence of complex numbers to obtain the second sequence of complex numbers with the first sequence of complex numbers again.Wherein, the second sequence of complex numbers comprises multiple second plural number.

In some embodiments of the invention, harmonic measurement device 410 carries out actual situation to the second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers, such as can comprise: in the second sequence of complex numbers comprising multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, and, described 3rd real equals imaginary part coefficient and the real part sum of second plural number corresponding to it, the imaginary part coefficient of described 3rd plural number equals the difference of second real corresponding to it and imaginary part coefficient, so, each second plural number in second sequence of complex numbers except the data corresponding to DC component and nyquist frequency point is done actual situation as above and combine the 3rd sequence of complex numbers that process just can obtain N point, namely the 3rd sequence of complex numbers comprises multiple 3rd plural number, wherein, 3rd sequence of complex numbers of this N point comprises the DC component in the second sequence of complex numbers and the data corresponding to nyquist frequency point, also comprise for each second plural number in the second sequence of complex numbers except the data corresponding to DC component and nyquist frequency point, three plural number corresponding with each second plural number described that the processing mode combined by actual situation is generated.

In some embodiments of the invention, 4th sequence of complex numbers is carried out actual situation and combines process to obtain N point harmonic sequence by harmonic measurement device 410, such as can comprise for comprising in the 4th sequence of complex numbers of multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, described 6th real equals imaginary part coefficient and the real part sum of four plural number corresponding to it, the imaginary part coefficient of described 6th plural number equals the difference of four real corresponding to it and imaginary part coefficient, so, each plural number in 4th sequence of complex numbers is done actual situation as above and combine the N point harmonic sequence that process just can obtain comprising multiple 6th plural number, wherein, this N point harmonic sequence comprises DC component and the data corresponding to nyquist frequency point in above-mentioned 4th sequence of complex numbers, also comprise for each the 4th plural number in above-mentioned 4th sequence of complex numbers except the data corresponding to DC component and nyquist frequency point, six plural number corresponding with each the 4th plural number described that the processing mode combined by actual situation is generated.

Wherein, twice real empty, and to combine the mode of process identical, can code multiplexing, and then be conducive to saving code memory space.The present embodiment scheme is without the need to carrying out conjugate operation, and only need simply add reducing to data, just can under less operand and the prerequisite not increasing additional memory units, realize multiplexing RFFT code and complete Harmonics Calculation, and Output rusults also can not need data to extract the operations such as sequence, may correspond to initial sequence of real numbers completely, be conducive to saving computing time, also can not increase extra code space and storage space.As the occasions such as harmonic amplitude, phase place, total harmonic distortion (THD) need be calculated, program's memory space can also be reduced by abundant multiplexing code.

In addition, in order to obtain real amplitude, in some embodiments of the invention, harmonic measurement device 410 can also reduce to amplitude, namely through the computing (can be described as 1/N operation in embodiments of the present invention) of " divided by N ".

For example, in one embodiment of this invention, harmonic measurement device 410 can by the electrical signal sequence of N point divided by N after, then the RFFT computing carrying out N point obtains the first sequence of complex numbers.

Or, in another embodiment of the invention, harmonic measurement device 410 can to the first sequence of complex numbers divided by N after carry out harmonic wave extraction process again and obtain the second sequence of complex numbers.

Or, in another embodiment of the invention, harmonic measurement device 410 can to the second sequence of complex numbers divided by N after, then carry out actual situation combine process to obtain the 3rd sequence of complex numbers.

Or, in another embodiment of the invention, harmonic measurement device 410 can to the 3rd sequence of complex numbers divided by N after carry out RFFT computing again and obtain the 4th sequence of complex numbers.

Or, in another embodiment of the invention, harmonic measurement device 410 can to the 4th sequence of complex numbers divided by N after, then carry out actual situation combine process to obtain N point harmonic sequence.

Or in another embodiment of the invention, the N obtained some harmonic sequence can also can export divided by after N by harmonic measurement device 410 again.

Be understandable that, harmonic measurement device 410 as harmonic measurement device 300, can have the part or all of function of harmonic measurement device 300.Each function of harmonic measurement device 410 can according to the method specific implementation in said method embodiment, and its specific implementation process see the associated description in said method embodiment, can repeat no more herein.

In some embodiments of the invention, the harmonic measurement device 410 in Harmonics elimination equipment 400 and electric signal feedback assembly 420 such as can be deployed in each power network topology as shown in Fig. 5 a-5c, to eliminate the harmonic wave in electrical network.

For further illustrating topology location and the effect of Harmonics elimination equipment 400 of the present invention, below for Harmonics elimination equipment 400 for APF/SVG, be described in conjunction with parallel connection type compensation harmonic electric current APF/SVG.It is worthy of note, those skilled in the art must know, the harmonic compensation principle of the present invention for series connection or series-parallel connection mode is same being suitable for, also within protection scope of the present invention.

See the configuration diagram of compensation that Fig. 5 b, Fig. 5 b is parallel access APF/SVG compensating power and harmonic wave, nonlinear load runs in electrical network, APF/SVG parallel connection access electrical network, to the harmonic wave of nonlinear load with idlely to compensate.Wherein i _s(figure comprises i _sa, i _sb, i _sc) be source current, i _l(figure comprises i _la, i _lb, i _lc) be load current, i _m(figure comprises i _ma, i _mb, i _mc) for electric signal feedback assembly 420 produce offset current.

To detect the harmonic component in load current by harmonic measurement device 410 wherein see Fig. 5 c, APF/SVG.Harmonic measurement device 410 output harmonic wave current sequence, idle pick-up unit 430 can adopt classical Instantaneous Power Theory to calculate and obtain load current fundamental wave reactive power, export reactive current sequence, reactive current sequence is added with harmonic current sequence, obtains the reactive current sequence and the harmonic wave current sequence that need compensation.Electric signal feedback assembly 420 in Fig. 5 c comprises: current controller 421, DC voltage controller 422 and power device 423 is (as insulated gate bipolar transistor (IGBT, InsulatedGateBipolarTransistor)), wherein, current controller 421 is connected with power device 423 with harmonic measurement device 410, idle pick-up unit 430, DC voltage controller 422, and DC voltage controller 422 is also connected with power device 423.DC voltage controller 422 is mainly used in exporting DC voltage regulation signal.DC voltage regulation signal production burst width modulated (PWM, the PulseWidthModulation) signal that current controller 421 is mainly used in exporting according to reactive current sequence, harmonic current sequence and DC voltage controller 422 exports.The pwm signal that power device 423 is mainly used in exporting according to current controller 421 produces and exports, to compensate the idle of load and harmonic current for compensation harmonic and idle current signal.The offset current i that power device 423 produces _m(figure comprises i _ma, i _mb, i _mc) can be contrary with the harmonic component equal and opposite in direction in load current, direction, thus the two can cancel each other, and makes in source current only containing basic real component.

The embodiment of the present invention also provides a kind of computer-readable storage medium, and wherein, this computer-readable storage medium can have program stored therein, and comprises the part or all of step of the data processing method recorded in said method embodiment when this program performs.

It should be noted that, for aforesaid each embodiment of the method, in order to simple description, therefore it is all expressed as a series of combination of actions, but those skilled in the art should know, the embodiment of the present invention is not by the restriction of described sequence of movement, because according to the embodiment of the present invention, some step can adopt other orders or carry out simultaneously.Secondly, those skilled in the art also should know, the embodiment described in instructions all belongs to preferred embodiment, and involved action and module might not be that the present invention is necessary.

In the above-described embodiments, the description of each embodiment is all emphasized particularly on different fields, in certain embodiment, there is no the part described in detail, can see the associated description of other embodiments.

To sum up, in the technical scheme that the embodiment of the present invention provides, the RFFT computing that electric signal of sampling from power circuit carries out N point with the electrical signal sequence obtaining N point is obtained the first sequence of complex numbers; Harmonic wave extraction process is carried out to the first sequence of complex numbers and obtains the second sequence of complex numbers; Actual situation is carried out to the second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers; RFFT computing is carried out to the 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; 4th sequence of complex numbers is carried out actual situation and combine process to obtain N point harmonic sequence, this programme without the need to carrying out conjugate operation before and after FFT, also without the need to data extraction operation, and only need carry out twice actual situation binding operation, namely simply add reducing, so in terms of existing technologies, comparatively save computing time, and carry out computing due to RFFT code can be made full use of, so also can code space be saved.

Further, do not need increase additional storage space, can code space, number of memory cells and computing time complex optimum.

One of ordinary skill in the art will appreciate that all or part of step in the various methods of above-described embodiment is that the hardware that can carry out instruction relevant by program has come, this program can be stored in a computer-readable recording medium, and storage medium can comprise: ROM (read-only memory), random access memory, disk or CD etc.

A kind of harmonic detecting method provided the embodiment of the present invention above and relevant apparatus are described in detail, apply specific case herein to set forth principle of the present invention and embodiment, the explanation of above embodiment just understands method of the present invention and core concept thereof for helping; Meanwhile, for one of ordinary skill in the art, according to thought of the present invention, all will change in specific embodiments and applications, to sum up, this description should not be construed as limitation of the present invention.

Accompanying drawing explanation

In order to be illustrated more clearly in the technical scheme of the embodiment of the present invention, be briefly described describing the required accompanying drawing used to embodiment below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is the schematic flow sheet of a kind of harmonic detecting method that the embodiment of the present invention provides;

Fig. 2 is the storage schematic diagram of the calculating data that the embodiment of the present invention provides;

Fig. 3 is the schematic diagram of a kind of harmonic measurement device that the embodiment of the present invention provides;

Fig. 4 is the schematic diagram of a kind of Harmonics elimination equipment that the embodiment of the present invention provides;

Fig. 5 a is a kind of configuration diagram be applied to by Harmonics elimination equipment in electrical network that the embodiment of the present invention provides;

Fig. 5 b be the embodiment of the present invention provide another Harmonics elimination equipment is applied to configuration diagram in electrical network;

Fig. 5 c is the configuration diagram that Harmonics elimination equipment is applied in electrical network by another kind that the embodiment of the present invention provides.

Embodiment

The embodiment of the present invention provides a kind of harmonic detecting method and relevant apparatus, can take into account storage space and computing time to harmonic detecting.

Below by specific embodiment, be described in detail respectively.

For making goal of the invention of the present invention, feature, advantage can be more obvious and understandable, below in conjunction with the accompanying drawing in the embodiment of the present invention, technical scheme in the embodiment of the present invention is clearly and completely described, obviously, the embodiments described below are only the present invention's part embodiments, and the embodiment of not all.Based on the embodiment in the present invention, those of ordinary skill in the art, not making other embodiments all obtained under creative work prerequisite, belong to the scope of protection of the invention.

Claims (7)

1. a harmonic detecting method, is characterized in that, comprising:

Sample electric signal to obtain the electrical signal sequence of N point from power circuit;

The Real Fast Fourier Transform RFFT computing that the electrical signal sequence of described N point carries out N point is obtained the first sequence of complex numbers;

Harmonic wave extraction process is carried out to described first sequence of complex numbers and obtains the second sequence of complex numbers;

Actual situation is carried out to described second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers, carry out actual situation to described second sequence of complex numbers to comprise in conjunction with process: in described second sequence of complex numbers comprising multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, wherein, described 3rd real equals imaginary part coefficient and the real part sum of corresponding second plural number, the imaginary part coefficient of described 3rd plural number equals the difference of corresponding second real and imaginary part coefficient,

Real Fast Fourier Transform RFFT computing is carried out to described 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; And

Described 4th sequence of complex numbers is carried out actual situation and combine process to obtain N point harmonic sequence, carry out actual situation to described 4th sequence of complex numbers to comprise in conjunction with process: in described 4th sequence of complex numbers comprising multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, wherein, described 6th real equals imaginary part coefficient and the real part sum of corresponding 4th plural number, the imaginary part coefficient of described 6th plural number equals the difference of corresponding 4th real and imaginary part coefficient.

2. harmonic detecting method according to claim 1, is characterized in that, described electric signal of sampling from power circuit comprises with the step of the electrical signal sequence obtaining N point:

Within a signal primitive period, from the sampling electric signal of power circuit equal intervals to obtain the electrical signal sequence of N point.

3. harmonic detecting method according to claim 1, is characterized in that, describedly carries out to described first sequence of complex numbers the step that harmonic wave extraction process obtains the second sequence of complex numbers and comprises:

Remove fundametal compoment in described first sequence of complex numbers to obtain described second sequence of complex numbers;

Or,

Make the harmonic component in described first sequence of complex numbers be zero to obtain the 5th sequence of complex numbers, then deduct described 5th sequence of complex numbers to obtain described second sequence of complex numbers with described first sequence of complex numbers again.

4. the harmonic detecting method according to any one of claims 1 to 3, it is characterized in that, the step that the Real Fast Fourier Transform RFFT computing that the described electrical signal sequence by described N point carries out N point obtains the first sequence of complex numbers comprises: by the electrical signal sequence of described N point divided by after described N, then the RFFT computing carrying out N point obtains the first sequence of complex numbers;

Or,

Describedly the step that harmonic wave extraction process obtains the second sequence of complex numbers carried out to described first sequence of complex numbers comprise: to described first sequence of complex numbers divided by described N after carry out harmonic wave extraction process again and obtain the second sequence of complex numbers;

Or,

Described to described second sequence of complex numbers carry out actual situation combine process comprise with the step obtaining the 3rd sequence of complex numbers: to described second sequence of complex numbers divided by described N after, then carry out actual situation combine process to obtain the 3rd sequence of complex numbers;

Or, describedly the step that RFFT computing obtains the 4th sequence of complex numbers carried out to described 3rd sequence of complex numbers comprise: to described 3rd sequence of complex numbers divided by described N after carry out RFFT computing again and obtain the 4th sequence of complex numbers;

Or,

Described described 4th sequence of complex numbers is carried out actual situation combine process comprise with the step obtaining N point harmonic sequence: will described 4th sequence of complex numbers divided by described N after, then carry out actual situation combination process to obtain N point harmonic sequence;

Or,

Described harmonic detecting method also comprises:

By the described N point harmonic sequence that obtains divided by described N.

5. a harmonic measurement device, is characterized in that, comprising:

Sampling unit, for electric signal of sampling from power circuit to obtain the electrical signal sequence of N point;

One RFFT arithmetic element, the Real Fast Fourier Transform RFFT computing that the electrical signal sequence for the N point obtained by described sampling unit carries out N point obtains the first sequence of complex numbers;

Harmonic extraction unit, the first sequence of complex numbers for obtaining a described RFFT arithmetic element carries out harmonic wave extraction process and obtains the second sequence of complex numbers;

Actual situation is in conjunction with processing unit, the second sequence of complex numbers for obtaining described harmonic extraction unit carries out actual situation and combines process to obtain the 3rd sequence of complex numbers, concrete, what described actual situation obtained in described harmonic extraction unit in conjunction with processing unit comprises in described second sequence of complex numbers of multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, wherein, described 3rd real equals imaginary part coefficient and the real part sum of corresponding second plural number, the imaginary part coefficient of described 3rd plural number equals the difference of corresponding second real and imaginary part coefficient, to obtain the 3rd sequence of complex numbers comprising multiple 3rd plural number,

2nd RFFT arithmetic element, obtains the 4th sequence of complex numbers for carrying out RFFT computing to described actual situation in conjunction with the 3rd sequence of complex numbers that processing unit obtains; And

Described actual situation in conjunction with processing unit also for, the 4th sequence of complex numbers that described 2nd RFFT arithmetic element obtains is carried out actual situation and combine process to obtain N point harmonic sequence, concrete, what described actual situation obtained in described 2nd RFFT arithmetic element in conjunction with processing unit comprises in the 4th sequence of complex numbers of multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, wherein, described 6th real equals imaginary part coefficient and the real part sum of corresponding 4th plural number, the imaginary part coefficient of described 6th plural number equals the difference of corresponding 4th real and imaginary part coefficient, to obtain the N point harmonic sequence comprising multiple 6th plural number.

6. harmonic measurement device according to claim 5, is characterized in that,

A described RFFT arithmetic element specifically for, the electrical signal sequence of the N point obtained by described sampling unit is divided by after described N, then the RFFT computing carrying out N point obtains the first sequence of complex numbers;

Or,

Described harmonic extraction unit specifically for, described first sequence of complex numbers that RFFT computing obtains is carried out divided by after described N to a described RFFT arithmetic element, then carries out harmonic wave extraction process and obtain the second sequence of complex numbers;

Or,

Described actual situation in conjunction with processing unit specifically for, described second sequence of complex numbers obtained described harmonic extraction unit divided by after described N, then carry out actual situation and combine process to obtain the 3rd sequence of complex numbers;

Or,

Described 2nd RFFT arithmetic element divided by after described N specifically for, the 3rd sequence of complex numbers obtained in conjunction with processing unit described actual situation, then is carried out RFFT computing and is obtained the 4th sequence of complex numbers;

Or,

Described actual situation in conjunction with processing unit also for, described 4th sequence of complex numbers that described 2nd RFFT arithmetic element is obtained divided by after described N, then carry out actual situation and combine process to obtain N point harmonic sequence;

Or,

Described actual situation is also carried out actual situation for, described 4th sequence of complex numbers described 2nd RFFT arithmetic element obtained in conjunction with processing unit and is combined process to obtain N point harmonic sequence, is exported by described N point harmonic sequence divided by after described N.

7. a Harmonics elimination equipment, is characterized in that, comprising:

Harmonic measurement device, for electric signal of sampling from power circuit to obtain the electrical signal sequence of N point; The Real Fast Fourier Transform RFFT computing that the electrical signal sequence of described N point carries out N point is obtained the first sequence of complex numbers; Harmonic wave extraction process is carried out to described first sequence of complex numbers and obtains the second sequence of complex numbers; Actual situation is carried out to described second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers; RFFT computing is carried out to described 3rd sequence of complex numbers and obtains the 4th sequence of complex numbers; Described 4th sequence of complex numbers is carried out actual situation and combine process to obtain N point harmonic sequence and to export;

Electric signal feedback assembly, the described N point harmonic sequence for exporting based on described harmonic measurement device generates and compensates electric signal, and the described compensation electric signal generated is fed back to described power circuit to eliminate the harmonic wave produced in described power circuit;

Wherein, described harmonic measurement device carries out actual situation to described second sequence of complex numbers and combines process to obtain the 3rd sequence of complex numbers, comprise: in described second sequence of complex numbers comprising multiple second plural number, each second plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates three plural number corresponding with each second plural number described, wherein, described 3rd real equals imaginary part coefficient and the real part sum of corresponding second plural number, the imaginary part coefficient of described 3rd plural number equals the difference of corresponding second real and imaginary part coefficient,

Described harmonic measurement device carries out actual situation to described 4th sequence of complex numbers and combines process to obtain N point harmonic sequence, comprise: in described 4th sequence of complex numbers comprising multiple 4th plural number, each the 4th plural number except the data corresponding to DC component and nyquist frequency point, the processing mode combined by actual situation generates six plural number corresponding with each the 4th plural number described, wherein, described 6th real equals imaginary part coefficient and the real part sum of corresponding 4th plural number, the imaginary part coefficient of described 6th plural number equals the difference of corresponding 4th real and imaginary part coefficient.