WO2013173975A1

WO2013173975A1 - Harmonic detection method and relevant device

Info

Publication number: WO2013173975A1
Application number: PCT/CN2012/075884
Authority: WO
Inventors: 刘海威
Original assignee: 深圳市英威腾电气股份有限公司
Priority date: 2012-05-22
Filing date: 2012-05-22
Publication date: 2013-11-28
Also published as: CN103547328B; CN103547328A

Abstract

A harmonic detection method and a relevant device. A harmonic detection method comprises: sampling an electrical signal from a power line to obtain an N-point electrical signal sequence; performing N-point real fast Fourier transform (RFFT) computation on the N-point electrical signal sequence to obtain a first complex sequence; performing harmonic extraction processing on the first complex sequence to obtain a second complex sequence; performing virtual-real combination processing on the second complex sequence to obtain a third complex sequence; performing RFFT computation on the third complex sequence to obtain a fourth complex sequence; and performing virtual-real combination processing on the fourth complex sequence to obtain an N-point harmonic sequence. The harmonic detection method and relevant device are favourable to taking both storage space and computation time into account during harmonic detection.

Description

^b wave detection method and related device

Technical field

The invention relates to the field of electronic technology, and in particular to a harmonic detection method and related device. Background technique

At present, various power electronic devices and non-linear loads are widely used in power systems, resulting in a large number of harmonics. Harmonics not only pose a threat to the safe operation of the power system itself, but also may have a great impact and harm to the surrounding electrical environment.

Active Power Filter (APF) is a power electronic device used to dynamically suppress harmonics and compensate reactive power. Static Var Generator (SVG) is one of the main devices in the Flexible AC Transmission System (FACTS). APF can compensate for harmonics and varying reactive powers that vary in size and frequency. APF's detection of harmonic signals is the key to ensuring its compensation performance. SVG can dynamically compensate for reactive power and compensate harmonics. SVG represents a new development direction of power system reactive power compensation technology. The same harmonic signal detection is the key to ensure SVG harmonic compensation performance.

Harmonic signals in power systems are usually referred to as current harmonics and voltage harmonics. Among them, when APF/SVG is deployed in parallel mode, current harmonics are usually detected and governed; when APF/SVG is deployed in series, voltage harmonics are usually detected and governed. Existing harmonic detection techniques are difficult to balance storage space and computing time. Summary of the invention

The embodiment of the invention provides a harmonic detection method and related device, so that the harmonic detection can take into account the storage space and the calculation time.

An embodiment of the present invention provides a harmonic detection method, including: sampling an electrical signal from a power line to obtain an electrical signal sequence of an N point; performing a real fast Fourier transform RFFT of the N point electrical signal sequence at an N point Computing to obtain a first complex sequence; performing harmonic extraction processing on the first complex sequence to obtain a second complex sequence; performing a virtual-real combination process on the second complex sequence to obtain a third complex sequence; Performing a real fast Fourier transform RFFT operation to obtain a fourth complex sequence; and performing a virtual real combining process on the fourth complex sequence to obtain an N point harmonic sequence. Optionally, the step of sampling the electrical signal from the power line to obtain the electrical signal sequence of the defect includes: sampling the electrical signal from the power line at intervals in a signal fundamental period to obtain the electrical signal sequence of the defect .

Optionally, the step of performing harmonic extraction processing on the first complex sequence to obtain the second complex sequence includes: removing a fundamental component in the first complex sequence to obtain the second complex sequence; or

The harmonic component of the first complex sequence is zeroed to obtain a fifth complex sequence, and then the fifth complex sequence is subtracted from the first complex sequence to obtain the second complex sequence.

Optionally, the step of performing a virtual real combining process on the second complex sequence includes: dividing, in the second complex sequence including the plurality of second complex numbers, a DC component and a Nyquist frequency point a second complex number corresponding to each of the second complex numbers is generated by each of the second complex numbers except the data, wherein the real part of the third complex number is equal to the imaginary part coefficient corresponding to the second complex number And the sum of the real parts, the imaginary part coefficient of the third complex number is equal to the difference between the real part and the imaginary part coefficient corresponding to the second complex number.

Optionally, the step of performing the virtual real combining process on the fourth complex sequence includes: selecting, in addition to the direct current component and the Nyquist frequency point, in the fourth complex sequence including the plurality of fourth complex numbers Each fourth complex number other than the data generates a sixth complex number corresponding to each of the fourth complex numbers by a combination of the virtual and real processes, wherein the real part of the sixth complex number is equal to the imaginary part coefficient corresponding to the fourth complex number And the sum of the real part, the imaginary part coefficient of the sixth complex number is equal to the difference between the real part and the imaginary part coefficient corresponding to the fourth complex number.

Optionally, the step of performing a real fast Fourier transform RFFT operation on the electrical signal sequence of the defect to obtain the first complex sequence comprises: dividing the electrical signal sequence of the defect by the Ν, Performing an RFFT operation of the defect to obtain a first complex sequence;

Or,

The step of performing harmonic extraction processing on the first complex sequence to obtain a second complex sequence includes: performing harmonic extraction processing on the first complex sequence by dividing the first complex sequence to obtain a second complex sequence;

or, The step of performing a virtual-real combination process on the second complex sequence to obtain a third complex sequence includes: after dividing the second complex sequence by the N, performing a virtual-real combination process to obtain a third complex sequence;

Or the step of performing an RFFT operation on the third complex sequence to obtain a fourth complex sequence includes: performing an RFFT operation on the third complex sequence by dividing the N to obtain a fourth complex sequence 歹' J;

Or,

The step of performing the virtual and real combination processing on the fourth complex sequence to obtain the N-point harmonic sequence includes: after dividing the fourth complex sequence by the N, performing a virtual-solid combination process to obtain an N-point harmonic Sequence

Or,

The harmonic detecting method further includes: dividing the obtained N-point harmonic sequence by the

Another aspect of the present invention provides a harmonic detecting apparatus, which may include: a sampling unit, configured to sample an electrical signal from a power line to obtain an electrical signal sequence of an N point; and a first RFFT operation unit for The N-point electrical signal sequence obtained by the sampling unit performs a real-time fast Fourier transform (RFFT) operation of the N-point to obtain a first complex sequence; a harmonic extraction unit is configured to harmonize the first complex sequence obtained by the first RFFT operation unit The wave extraction process obtains a second complex sequence; the virtual real combining processing unit is configured to perform a virtual real combination process on the second complex sequence obtained by the harmonic extraction unit to obtain a third complex sequence; and a second RFFT operation unit, The third complex sequence obtained by the virtual and real processing unit performs an RFFT operation to obtain a fourth complex sequence; and the virtual real processing unit is further configured to perform a virtual real combination process on the fourth complex sequence obtained by the second RFFT operation unit. A sequence of N points of harmonics is obtained.

Optionally, the virtual and real combination processing unit is specifically configured to: in the second complex sequence including the plurality of second complex numbers obtained by the harmonic extraction unit, corresponding to a DC component and a Nyquist frequency point For each second complex number other than the data, a third complex number corresponding to each of the second complex numbers is generated by a combination of the virtual and real processes, wherein the real part of the third complex number is equal to the imaginary part corresponding to the second complex number The sum of the coefficient and the real part, the imaginary part coefficient of the third complex number is equal to the difference between the real part and the imaginary part coefficient corresponding to the second complex number, to obtain a third complex sequence including a plurality of third complex numbers. Optionally, the virtual and real combination processing unit is further configured to: in the fourth complex sequence including the plurality of fourth complex numbers obtained by the second RFFT operation unit, corresponding to the DC component and the Nyquist frequency point For each fourth complex number other than the data, a sixth complex number corresponding to each of the fourth complex numbers is generated by a combination of the virtual and real processes, wherein the real part of the sixth complex number is equal to the imaginary part corresponding to the fourth complex number The sum of the coefficient and the real part, the imaginary part coefficient of the sixth complex number is equal to the difference between the real part and the imaginary part coefficient corresponding to the fourth complex number, to obtain an N-point harmonic sequence including a plurality of sixth complex numbers.

Optionally, the first RFFT operation unit is specifically configured to: after dividing the electrical signal sequence of the N points obtained by the sampling unit by the N, perform an RFFT operation of an N point to obtain a first complex sequence; or

The harmonic extraction unit is specifically configured to: after the first complex sequence obtained by performing an RFFT operation on the first RFFT operation unit is divided by the N, perform harmonic extraction processing to obtain a second complex sequence 歹' J ;

Or,

The virtual and real combination processing unit is specifically configured to: after dividing the second complex sequence obtained by the harmonic extraction unit by the N, perform a virtual real combination process to obtain a third complex sequence;

Or,

The second RFFT operation unit is specifically configured to: after dividing the third complex sequence obtained by the virtual and real combination processing unit by the N, perform an RFFT operation to obtain a fourth complex sequence;

Or,

The virtual real processing unit is further configured to: after dividing the fourth complex sequence obtained by the second RFFT operation unit by the N, perform a virtual real combining process to obtain an N point harmonic sequence;

Or,

The virtual real processing unit is further configured to perform a virtual real combining process on the fourth complex sequence obtained by the second RFFT operation unit to obtain an N point harmonic sequence, and divide the N point harmonic sequence by the Output after N.

A still further aspect of the present invention provides a harmonic elimination device, including:

a harmonic detecting device, configured to sample an electrical signal from a power line to obtain an electrical signal sequence of an N point; and perform a real fast Fourier transform RFFT operation of the N point electrical signal sequence to obtain a first a complex sequence; performing harmonic extraction processing on the first complex sequence to obtain a second complex sequence; performing a virtual-real combination process on the second complex sequence to obtain a third complex sequence; and performing an RFFT operation on the third complex sequence a fourth complex sequence; and performing a virtual-solid combination process on the fourth complex sequence to obtain an N-point harmonic sequence and outputting;

An electric signal feedback device, configured to generate a compensation electric signal based on the N-point harmonic sequence output by the harmonic detecting device, and feed back the generated compensation electric signal to the power line to eliminate generation in the power line Harmonics.

Another aspect of the present invention further provides a computer storage medium storing a program, where the program includes some or all of the steps of the method embodiment.

As can be seen from the above, in the technical solution provided by the embodiment of the present invention, the electrical signal is sampled from the power line to obtain the electrical signal sequence of the N point, and the R complex operation of the N point is performed to obtain the first complex sequence; and the first complex sequence is subjected to harmonic extraction. Processing to obtain a second complex sequence; performing a virtual-real combination process on the second complex sequence to obtain a third complex sequence; performing an RFFT operation on the third complex sequence to obtain a fourth complex sequence; and performing a virtual-solid combination process on the fourth complex sequence to obtain an N-point Harmonic sequence. The technical solution does not need to perform the conjugate operation before and after the RFFT, and does not need the data extraction operation, and only needs to perform the virtual and real combination processing operations twice, that is, the addition and subtraction operation of the single-single, so the calculation is relatively saved compared with the prior art. Time, and because the RFFT code can be fully utilized for operation, it also saves code space.

Further, no additional storage space is required, and the code space, the number of storage units, and the calculation time can be comprehensively optimized. DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings to be used in the following description of the embodiments will be briefly described. It is obvious that the drawings in the following description are only some embodiments of the present invention, Those skilled in the art can also obtain other drawings based on these drawings without paying any creative work.

1 is a schematic flow chart of a harmonic detecting method according to an embodiment of the present invention;

2 is a schematic diagram of storage of calculation data provided by an embodiment of the present invention;

3 is a schematic diagram of a harmonic detecting apparatus according to an embodiment of the present invention;

4 is a schematic diagram of a harmonic elimination device according to an embodiment of the present invention; FIG. 5a is a schematic structural diagram of applying a harmonic elimination device to a power grid according to an embodiment of the present invention; FIG.

FIG. 5b is a schematic diagram of another architecture for applying a harmonic elimination device to a power grid according to an embodiment of the present invention; FIG.

FIG. 5c is a schematic diagram of another architecture for applying a harmonic elimination device to a power grid according to an embodiment of the present invention. detailed description

The detailed description will be respectively made below through specific embodiments.

In order to make the object, the features and the advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the invention, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts are within the scope of the present invention.

The terms "first", "second", "third", "fourth", etc. (if present) in the specification and claims of the present invention and the above figures are used to distinguish similar objects without being used for Describe a specific order or order. It is to be understood that the data so used may be interchanged as appropriate, so that the embodiments of the invention described herein can be implemented, for example, in a sequence other than those illustrated or described herein. In addition, the terms "comprises" and "comprises" and "comprises" and "includes" or "includes" or "comprises" or "comprises" or "comprises" Those steps or units may include other steps or units not explicitly listed or inherent to such processes, methods, products or devices.

The harmonic signal detection range of the present invention includes detection of harmonic voltages and/or harmonic currents.

The main methods of harmonic signal detection are: analog band-pass filter detection method, detection method based on instantaneous reactive power theory, fast Fourier transform (FFT) detection method and so on. The detection method based on the analog fusion filter can only detect harmonics in a fixed frequency range, can not compensate the changed harmonics in real time, and easily cause resonance; fast Fourier transform method and based on instantaneous reactive power The power theory detection method can detect harmonics in a wide frequency range and, therefore, is widely used in power systems. The detection method based on instantaneous reactive power has unique advantages in the overall compensation and fast response of reactive power and harmonics, and the FFT detection method is irreplaceable in the detailed analysis of the signal spectrum and data display, especially in the harmonics. The advantages of content analysis and individual compensation for individual spectrum are obvious. Considering the duality of FFT and IFFT, for those devices that have used the FFT detection method for harmonic content analysis and display (such as partial APF and SVG), it is possible to directly call the existing code for inverse transformation to obtain harmonic instructions. The application of FFT in these applications is more advantageous. The FFT-based harmonic extraction method is more complicated in calculation, less real-time, and more memory in calculation.

When APF/SVG needs to compensate for one or several specific subharmonics at the same time, the FFT calculation is indispensable. The harmonic signal extraction based on the FFT inverse transform principle takes more memory and the program operation time is longer. Applications are blocked in large-scale real-time processing.

Some improved FFT-based harmonic detection methods are as follows:

(1) The FFT calculation is used to obtain the harmonic sequence. Although the forward and reverse transforms can share the same FFT block, the cost is reduced by the positive transform efficiency, and the storage space is increased by one time. For the inverse transform method, additional conjugate is needed (or Sort) operations and data extraction operations.

(2) The real-time and complex FFT are combined to calculate the harmonic sequence. The forward transform operation time and storage space can be optimized. Although the former method improves the efficiency of forward transform, this method sacrifices code sharing and increases. The complexity of the program.

(3) The real-time fast Fourier transform (RFFT, Real number FFT) is used to calculate the harmonic sequence. Although this method can be code-multiplexed, it additionally increases the storage space by one time, and requires two real virtual separation operations. Increased, affecting the computing speed of the processor. It can be seen that each of the above methods has advantages and disadvantages, and there is no comprehensive performance that can balance code reuse, storage space and calculation time. An embodiment of the harmonic detecting method of the present invention may include: sampling an electrical signal from a power line to obtain an electrical signal sequence of an N point; performing an N-point real-time fast Fourier transform RFFT operation on the N-point electrical signal sequence a complex sequence; performing harmonic extraction processing on the first complex sequence to obtain a second complex sequence; performing a virtual real combination process on the second complex sequence to obtain a third complex sequence; performing an RFFT operation on the third complex sequence to obtain a fourth complex sequence; Combining the fourth complex sequence with virtual and real To get the N point harmonic sequence.

Referring to FIG. 1, FIG. 1 is a schematic diagram of a harmonic detection method according to an embodiment of the present invention, which may include the following contents:

Step 101: Sample an electrical signal from the power line to obtain an electrical signal sequence of the N point.

In some embodiments of the invention, electrical signals may be sampled at equal or unequal intervals from the power line during a signal fundamental period to obtain an electrical signal sequence at point N. For example, a three-phase current signal (or a three-phase voltage signal) at equal intervals or unequal intervals in a signal fundamental period can be extracted from a three-phase power line to obtain an N-point current signal corresponding to each phase current. Sequence (or N-point voltage signal sequence).

Step 102: Perform an RFFT operation of the N point electrical signal sequence to obtain a first complex sequence. The first complex sequence includes a plurality of first complex numbers.

Referring to FIG. 2, FIG. 2 is a schematic diagram of storage of computing data according to an embodiment of the present invention. As shown in Figure 2, the sequence of electrical signals at point N is expressed as ! ^~!^^, suppose that N memory cells are used to store the N-point electrical signal sequence (R.~R _N 4 ), and the N-point electrical signal sequence (R.~R _N4 ) is subjected to the N-point RFFT operation. a complex sequence storing data corresponding to a direct current component and a Nyquist frequency point in the first complex sequence (eg, R ₀ and R _N/2 ) in two memory locations, and may also retain the remaining N in the first complex sequence - The real part of (N-2)/2 complex numbers (Ι^~Ι _Ν/2 4 ) in 2 complex numbers is stored in (N-2)/2 memory cells, and the (N-2) The imaginary part of the /2 complex number is stored in (N-2)/2 memory cells because the data corresponding to the DC component and the Nyquist frequency point are removed in the first complex sequence (such as R. and R _N/2). The real and imaginary coefficients of the two partial complex numbers (~11⁄2 _/2-1 ) and (R _N /2 ₊ 1~RN-1 ) have conjugate symmetry, so the stored complex number is used (R^Rn ), the complex number that is not stored in the first complex sequence can be recovered, which can save a large storage space. Of course, the (R _N/2+1 ~R _N4 ) part in the first complex sequence can also be stored, and the first part is not stored. In a complex sequence

), and according to (R _N /2 ₊ 1~RN-1), the ( ) part can also be recovered. It will be appreciated that complex numbers having conjugate symmetry in other complex sequences may also be stored in this manner.

Referring to FIG. 1, step 103, performing harmonic extraction processing on the first complex sequence to obtain a second complex sequence.

In some embodiments of the present invention, performing harmonic extraction processing on the first complex sequence to obtain a second complex number The sequence of steps may include: removing a fundamental component in the first complex sequence to obtain a second complex sequence (of course, harmonic components of an unnecessary number of times may also be removed, that is, only one or several set times may be extracted Harmonic component), for example, may make the fundamental component in the first complex sequence zero to obtain the second complex sequence; or, the harmonic component in the first complex sequence may be zero to obtain the first The fifth complex sequence is then subtracted from the first complex sequence by the first complex sequence to obtain a second complex sequence.

The second complex sequence includes a plurality of second complex numbers.

Step 104: Perform a virtual and real combination process on the second complex sequence to obtain a third complex sequence.

In some embodiments of the present invention, for example, in a second complex sequence including a plurality of second complex numbers, each second complex number other than the data corresponding to the direct current component and the Nyquist frequency point is combined by virtual and real a processing manner of generating a third complex number corresponding to each of the second complex numbers, and wherein a real part of the third complex number is equal to a sum of an imaginary part coefficient and a real part of the corresponding second complex number, the third complex number The imaginary part coefficient is equal to the difference between the real part and the imaginary part coefficient corresponding to the second complex number, such that each second of the second complex sequence except the data corresponding to the direct current component and the Nyquist frequency point is second The complex complex processing as described above can obtain the third complex sequence of N points, that is, the third complex sequence includes a plurality of third complex numbers, wherein the third complex sequence of the N points includes the second complex sequence The data corresponding to the direct current component and the Nyquist frequency point further includes, for the second complex number, each second complex number other than the data corresponding to the direct current component and the Nyquist frequency point, Virtual and treatment had generated a third plurality and said second plurality each corresponding.

Step 105: Perform an RFFT operation on the third complex sequence to obtain a fourth complex sequence.

The fourth complex sequence includes a plurality of fourth complex numbers.

Step 106: Perform a virtual-solid combination process on the fourth complex sequence to obtain an N-point harmonic sequence.

In some embodiments of the present invention, for example, in a fourth complex sequence including a plurality of fourth complex numbers, each fourth complex number other than the data corresponding to the direct current component and the Nyquist frequency point is passed through the virtual reality The combined processing manner generates a sixth complex number corresponding to each of the fourth complex numbers, the real part of the sixth complex number is equal to the sum of the imaginary part coefficient and the real part of the corresponding fourth complex number, and the virtual number of the sixth complex number The coefficient of the part is equal to the difference between the real part and the imaginary part coefficient of the fourth complex number corresponding thereto, so that each of the fourth complex sequence is subjected to the virtual and real combination processing as described above to obtain a plurality of sixth complex numbers. An N-point harmonic sequence, wherein the N-point harmonic sequence includes a DC component and a Nyquist in the fourth complex sequence The data corresponding to the frequency point further includes, for the fourth complex sequence in the fourth complex sequence, each fourth complex number except the data corresponding to the direct current component and the Nyquist frequency point, generated by the combination of the virtual and real processing The sixth complex number corresponding to each fourth complex number.

Among them, the two real and virtual combined processing methods are the same, which can realize code multiplexing, which is beneficial to save code storage space. In this embodiment, the conjugate operation is not required, and only the addition and subtraction operations of the data are performed, and the harmonic calculation of the multiplexed RFFT code can be realized with less computational complexity and without adding additional storage units. And the output result does not need operations such as data extraction sorting, and can completely correspond to the original real sequence, which is beneficial to save computation time and does not add extra code space and storage space. If you need to calculate harmonic amplitude, phase, total harmonic distortion (THD), etc., you can also fully reuse the code to reduce the program memory space.

It should be noted that N in the embodiment of the present invention refers to the number of points of the inverse Fourier transform, that is, the length of the harmonic sequence output.

Furthermore, in order to obtain a true amplitude, the amplitude can also be restored, i.e., subjected to a "divide by N" operation (which may be referred to as a 1/N operation in the embodiment of the present invention).

For example, in an embodiment of the present invention, performing the RFFT operation of the N-point electrical signal sequence in step 102 to obtain the first complex sequence may include the following specific steps: dividing the electrical signal sequence of the N point After N, an N-point RFFT operation is performed to obtain a first complex sequence.

Alternatively, in another embodiment of the present invention, performing harmonic extraction processing on the first complex sequence in step 103 to obtain the second complex sequence may include the following specific steps: performing harmonics after dividing the first complex sequence by N The wave extraction process results in a second complex sequence.

Alternatively, in another embodiment of the present invention, performing the virtual real combining process on the second complex sequence in step 104 to obtain the third complex sequence may include the following specific steps: after dividing the second complex sequence by N, The virtual and real combination processing is performed to obtain a third complex sequence.

Alternatively, in another embodiment of the present invention, performing an RFFT operation on the third complex sequence in step 105 to obtain the fourth complex sequence may include the following specific steps: performing an RFFT operation after dividing the third complex sequence by N The fourth plural sequence.

Alternatively, in another embodiment of the present invention, performing the virtual real combining process on the fourth complex sequence to obtain the N point harmonic sequence in step 106 includes the following specific steps: dividing the fourth complex sequence After N, the virtual and real combination processing is performed to obtain an N-point harmonic sequence.

Alternatively, in another embodiment of the present invention, the obtained N-point harmonic sequence may be divided by N and output. In order to facilitate a better understanding of the embodiments of the present invention, the basis of the method provided by the embodiments of the present invention will be analyzed.

For RFFT, the sampled electrical signal sequence can be expressed as: x(n) = x _R (n) , 0<n<Nl Since the imaginary part of the sampled electrical signal sequence is 0, the DFT definition and properties can be obtained. Out:

N-1 N-l

2πΙσι

DFT: X _R (k) =∑ x _R (n) cos h Xj (n) sin - n=0 NNN

2nkn

Ν That is, after RFFT, the real part is a cosine component, which is a real even sequence, and the imaginary part is a sinusoidal component, which is a real odd sequence.

For the inverse Fourier transform, the input sequence is:

X(k) = X _R (k) + jX _I ) , 0 ≤ k ≤ N_l The inverse transformation result is χ(η), which is obtained according to the properties of the inverse Fourier transform:

x(n) = IFFT(X(k))

= IFFT(X _R (k)+jX _I = IFFT(X _R (k))+ j^IFFTiX^k)) = conj(FFT(X _R (k))) + j^conj(FFT(X = FFT (X _R (k)) + j^(-l)^(FFT(X _I It can be obtained: x(n) = FFT(X _R (k)) - jHFFT(X _] where 0 ≤ k ≤ Nl. It should be noted that the 1/N operation is omitted in the above formula, considering 1/N It only affects the final amplitude, so no analysis is done here. It is understandable that if you need to get the true amplitude, you can perform 1/N operation on the result. By _(n) = FFT(X _R (k)) - j * (FFT(X _I (k))) It can be seen that there are still two FFT transforms in the result, and each transform requires N data. Therefore, the equation x(n) = FFT (X _R ) is also needed. (k)) - j * (FFT(X _I (k))

For further analysis, let's find the FFT on both sides of s(o = ^ +x, then ^?0 = +x ) to get:

S(K) = X _R (k) + X _I (k) · where FFT (X _R (k)) is a pure real number and FFT (X: (k)) is a pure imaginary number.

Therefore, you can get:

s = FFT(X _R (k)) + FFTiX^k) )=s _R+ j* _Sl where _{0 ≤ k ≤ N} _ _l; where s = FFTiX^ + FFTiX^k) )=s _R +j The second FFT-j FFT ring can be transformed into: (n) = s _R + Sj where Q _{≤ k ≤ N} γ. By formulating S (K) and FFTing it, you can pass the formula

Restore the original real sequence x(n). Actually for the storage list x(n) = s _R +s

In the case where the number of elements is the same, it is necessary to construct an expression in which S (K) and the formula are exactly the same, so that one block can be shared. It can be seen from Fig. 2 that after a typical N-point real number sequence is RFFT-transformed, only half of the data (ie, the spectral value) can be stored by its conjugate symmetry, so if N points are to be calculated, the other half needs to be restored. The data, because the other half of the data is conjugate symmetric with the saved data, so the construction of S (K) can be decomposed into: x _R m, where, =ο

X _R (K) + X!(K) , where 0 ≤ ≤ /2- 1

X _R (N 12) , where = /2

X N-K)-XAN-K) , real , Ν ί2 ≤ Κ ≤ Ν Obviously, χ (η) can also be implemented by the above method, and will not be described here.

As can be seen from the above, in this embodiment, the electrical signal is sampled from the power line to obtain an electrical signal sequence of N points, and the R complex operation of the N point is performed to obtain the first complex sequence; the second complex sequence is obtained by performing harmonic extraction processing on the first complex sequence. Performing a virtual-real combination process on the second complex sequence to obtain a third complex sequence; performing an RFFT operation on the third complex sequence to obtain a fourth complex sequence; and performing a virtual-solid combination process on the fourth complex sequence to obtain an N-point harmonic sequence, the solution There is no need to perform a conjugate operation before and after the RFFT, and no data extraction operation is required, and only two virtual and real combining operations are performed, that is, the addition and subtraction operations of the cartridge are performed, so that the calculation time is saved compared with the prior art, and You can take full advantage of the RFFT code for calculations, so you can save code space. Further, without additional storage space, the code space, the number of storage units, and the calculation time can be comprehensively optimized. In order to facilitate a better understanding and implementation of the above described embodiments of the embodiments of the present invention, related apparatus for implementing the above aspects are also provided below. Referring to FIG. 3, an embodiment of the present invention further provides a harmonic detecting apparatus 300, which may include: a sampling unit 301, a first RFFT operation unit 302, a harmonic extraction unit 303, a virtual real processing unit 304, and a second RFFT operation unit. 305.

The sampling unit 301 is configured to sample an electrical signal from the power line to obtain an electrical signal sequence of the N point.

In some embodiments of the present invention, the sampling unit 301 can sample electrical signals from the power line at intervals or unequal intervals within a signal fundamental period to obtain an electrical signal sequence at point N. For example, the sampling unit 301 can extract a three-phase current signal (or a three-phase voltage signal) at equal intervals or unequal intervals in a signal fundamental period from a three-phase power line to obtain a sequence of N-point current signals of each phase current ( Or N point voltage signal sequence).

The first RFFT operation unit 302 is configured to perform an N-point real-time fast Fourier transform RFFT operation on the N-point electrical signal sequence obtained by the sampling unit 301 to obtain a first complex sequence. The first complex sequence includes a plurality of first complex numbers.

The harmonic extraction unit 303 is configured to perform harmonic extraction processing on the first complex sequence obtained by the first RFFT operation unit 302 to obtain a second complex sequence. The second complex sequence includes a plurality of second complex numbers.

The virtual and real combination processing unit 304 is configured to perform a virtual and real combination process on the second complex sequence obtained by the harmonic extraction unit 303 to obtain a third complex sequence. The third complex sequence includes a plurality of third complex numbers.

The second RFFT operation unit 305 is configured to perform an RFFT operation on the third complex sequence obtained by the virtual real combining processing unit 304 to obtain a fourth complex sequence. The fourth complex sequence includes a plurality of fourth complex numbers.

The virtual real processing unit 303 is further configured to perform a virtual real combining process on the fourth complex sequence obtained by the second RFFT operation unit 305 to obtain an N point harmonic sequence.

In some embodiments of the present invention, the virtual real processing unit 304 may be specifically configured to: in addition to the direct current component and the Nyquist frequency point, in the second complex sequence including the plurality of second complex numbers obtained by the harmonic extracting unit 303 a second complex number corresponding to each of the second complex numbers is generated by each of the second complex numbers except the corresponding data, and the real part of the third complex number is equal to the second complex number corresponding thereto The sum of the imaginary part coefficient and the real part, the imaginary part coefficient of the third complex number is equal to the difference between the real part and the imaginary part coefficient corresponding to the second complex number, and the second and second complex numbers are combined by the virtual and real parts to obtain the first Three complex sequences. In some embodiments of the present invention, the virtual real processing unit 304 is further configured to: in addition to the DC component and the Nyquist frequency point, the fourth complex sequence including the plurality of fourth complex numbers obtained by the second RFFT operation unit 305 a fourth complex number corresponding to each of the fourth complex numbers is generated by each of the fourth complex numbers other than the corresponding data, and the real part of the sixth complex number is equal to the fourth complex number corresponding thereto The sum of the imaginary part coefficient and the real part, the imaginary part coefficient of the sixth complex number is equal to the difference between the real part and the imaginary part coefficient of the corresponding fourth complex number, and each of the fourth complex numbers is subjected to a combination of virtual and real processing to obtain A plurality of sixth complex N-point harmonic sequences are included.

It can be understood that the third complex sequence obtained by the virtual reality combining processing unit 304 includes the DC component in the second complex sequence and the data corresponding to the Nyquist frequency point, and further includes a DC component and a Nyquivalent component in the second complex sequence. Each second complex number other than the data corresponding to the sterling frequency point is a third complex number corresponding to each of the second complex numbers generated by the combination of the virtual and real processing. The N-point harmonic sequence obtained by the virtual-real combination processing unit 304 includes data corresponding to the DC component and the Nyquist frequency point in the fourth complex sequence, and further includes a DC component and a Nyquivalent component in the fourth complex sequence. Each fourth complex number other than the data corresponding to the sterling frequency point is a sixth complex number corresponding to each of the fourth complex numbers generated by the combination of the virtual and real processing.

In some embodiments of the present invention, the harmonic extraction unit 303 is specifically configured to remove the fundamental component in the first complex sequence to obtain a second complex sequence.

In some embodiments of the present invention, the first RFFT operation unit 302 may be specifically configured to divide the electrical signal sequence of the N point obtained by the sampling unit 301 by N, and then perform an RFFT operation of the N point to obtain the first complex sequence.

Or,

The harmonic extraction unit 303 is specifically configured to perform a second complex sequence after the first complex sequence obtained by performing the RFFT operation on the first RFFT operation unit 302 is divided by N.

or, The virtual and real combination processing unit 304 is specifically configured to perform a virtual real combining process on the second complex sequence obtained by the harmonic extracting unit 303 by dividing N to obtain a third complex sequence.

Or,

The second RFFT operation unit 305 is specifically configured to perform a RFFT operation on the third complex sequence obtained by dividing the third complex sequence obtained by the virtual and real combination processing unit 304 by N to obtain a fourth complex sequence.

Or,

The virtual real processing unit 304 is further configured to divide the fourth complex sequence obtained by the second RFFT operation unit 305 by N, and then perform a virtual real combining process to obtain an N point harmonic sequence.

Or,

The virtual real processing unit 304 is further configured to perform a virtual real combining process on the fourth complex sequence obtained by the second RFFT operation unit 305 to obtain an N point harmonic sequence, and output the N point harmonic sequence by N and output.

It is to be understood that the functions of the functional modules of the harmonic detecting apparatus 300 of the present embodiment may be specifically implemented according to the method in the foregoing method embodiments. For the specific implementation process, refer to the related description in the foregoing method embodiments, and details are not described herein again. . The harmonic detecting device 300 of the present embodiment can be deployed in the APF/SVG as a means for performing harmonic detection in the APF/S VG. Referring to FIG. 4, an embodiment of the present invention further provides a harmonic elimination device 400, which may include: a harmonic detection device 410 and an electrical signal feedback device 420.

The harmonic detecting device 410 is configured to sample an electrical signal from the power line to obtain an electrical signal sequence of the N point; perform an RFFT operation of the N point electrical signal sequence to obtain a first complex sequence; The sequence is subjected to harmonic extraction processing to obtain a second complex sequence; the second complex sequence is subjected to virtual and real combination processing to obtain a third complex sequence; the third complex sequence is subjected to RFFT operation to obtain a fourth complex sequence; and the fourth complex sequence is subjected to virtual and real combination. Process to obtain an N-point harmonic sequence and output.

The electrical signal feedback device 420 is configured to generate a compensated electrical signal based on the N-point harmonic sequence output by the harmonic detecting device 410, and feed the generated compensated electrical signal to the power line to eliminate harmonics generated in the power line.

In some embodiments of the present invention, the harmonic detecting means 410 may sample the electrical signals from the power line at intervals or unequal intervals within a signal fundamental period to obtain an electrical signal sequence of N points. For example The harmonic detecting device 410 can extract, for example, three-phase current signals (or three-phase voltage signals) at equal intervals or unequal intervals in a signal fundamental period from the three-phase power line to obtain N points of each phase current. Current signal sequence (or N-point voltage signal sequence).

In some embodiments of the present invention, the harmonic detecting device 410 may employ, for example, a data storage method as shown in FIG. 2 for data storage. For example, the sequence of electrical signals at point N is expressed as! ^~!^^, suppose that N memory cells are used to store the N-point electrical signal sequence (R^R^), and the N-point electrical signal sequence (R^R^) is subjected to the N-point RFFT operation to obtain the first complex sequence. And storing the data corresponding to the direct current component and the Nyquist frequency point in the first complex sequence (such as R. and R _N/2 ) in two storage units, and further remaining N-2 in the first complex sequence The real part of (N-2)/2 complex numbers (R^RN/W) in the complex number is stored in (N-2)/2 memory cells, and the (N-2)/2 complex virtual The partial coefficients are stored in (N-2) /2 memory locations because of the two parts of the first complex sequence except for the DC component and the Nyquist frequency point corresponding to the data (such as R. and R _N/2 ). The real and imaginary coefficients of the complex numbers (R RN/W ) and (R _N /2 ₊ 1~RN-1 ) have conjugate symmetry, so the first complex (R^RN^ ) can be used to recover the first The complex sequence is not stored in a complex number, which can save a large storage space. Of course, the harmonic detecting device 410 can also store the (R _N/2+1 ~R _N4 ) portion in the first complex sequence, and does not store the first complex sequence. the (R Canton R _N / 24), and _{(R N / 2 + 1 ~} RN-1) can recover (R ^ RN / W) section. It will be appreciated that complex numbers having conjugate symmetry in other complex sequences may also be stored in this manner.

In some embodiments of the present invention, the harmonic detecting apparatus 410 performs harmonic extraction processing on the first complex sequence to obtain the second complex sequence, for example, including: removing the fundamental component in the first complex sequence to obtain the second complex sequence (of course It is also possible to remove unwanted harmonic components, that is, to extract only one or several set times of harmonic components, for example, for example, the fundamental component in the first complex sequence can be zero. Obtaining a second complex sequence; or alternatively, the harmonic components in the first complex sequence are zero to obtain a fifth complex sequence, and then subtracting the fifth complex sequence from the first complex sequence to obtain a second complex sequence. The second complex sequence includes a plurality of second complex numbers.

In some embodiments of the present invention, the harmonic detecting device 410 performs a virtual real combining process on the second complex sequence to obtain a third complex sequence. For example, the method may include: excluding a DC component in the second complex sequence including the plurality of second complex numbers And each second complex number other than the data corresponding to the Nyquist frequency point, the third complex number corresponding to each of the second complex numbers is generated by a combination of the virtual and real processing, and The real part of the third complex number is equal to the sum of the imaginary part coefficient and the real part of the second complex number, and the imaginary part coefficient of the third complex number is equal to the difference between the real part and the imaginary part coefficient corresponding to the second complex number, so that a second complex sequence of N points, that is, a second complex sequence of the second complex number in the second complex sequence except for the data corresponding to the direct current component and the Nyquist frequency point is processed as described above. The triple complex sequence includes a plurality of third complex numbers, wherein the third complex sequence of the N points includes data corresponding to the direct current component and the Nyquist frequency point in the second complex sequence, and is further included in the second complex sequence Each of the second complex numbers other than the data corresponding to the DC component and the Nyquist frequency point, the third complex number corresponding to each of the second complex numbers generated by the combination of the virtual and real processes.

In some embodiments of the present invention, the harmonic detecting device 410 performs a virtual-real combining process on the fourth complex sequence to obtain an N-point harmonic sequence, for example, may include a DC component in a fourth complex sequence including a plurality of fourth complex numbers. And each fourth complex number other than the data corresponding to the Nyquist frequency point, a sixth complex number corresponding to each of the fourth complex numbers is generated by a combination of the virtual and real processing, and the real part of the sixth complex number is equal to Corresponding to the sum of the imaginary part coefficient and the real part of the fourth complex number, the imaginary part coefficient of the sixth complex number is equal to the difference between the real part and the imaginary part coefficient corresponding to the fourth complex number, so that the fourth complex sequence is Each of the complex numbers performs the virtual-real combination processing as described above to obtain an N-point harmonic sequence including a plurality of sixth complex numbers, wherein the N-point harmonic sequence includes the DC component and the Nyquist in the fourth complex sequence. The data corresponding to the frequency point further includes each fourth complex number except the data corresponding to the direct current component and the Nyquist frequency point in the fourth complex sequence, through the virtual solid node The sixth complex number corresponding to each of the fourth complex numbers generated by the combined processing manner.

In addition, in order to obtain a true amplitude, in some embodiments of the present invention, the harmonic detecting device 410 can also restore the amplitude, that is, after a "divide by N" operation (in the embodiment of the present invention Called 1/N operation).

For example, in an embodiment of the present invention, the harmonic detecting means 410 may perform the RFFT operation of the N point to obtain the first complex sequence after dividing the signal sequence of the N point by N.

Alternatively, in another embodiment of the present invention, the harmonic detecting means 410 may perform harmonic extraction processing after dividing the first complex sequence by N to obtain a second complex sequence.

Alternatively, in another embodiment of the present invention, the harmonic detecting means 410 may perform a virtual real combining process after dividing the second complex sequence by N to obtain a third complex sequence.

Alternatively, in another embodiment of the present invention, the harmonic detecting means 410 may perform an RFFT operation after dividing the third complex sequence by N to obtain a fourth complex sequence.

Alternatively, in another embodiment of the present invention, the harmonic detecting means 410 may perform a virtual real combining process after dividing the fourth complex sequence by N to obtain an N point harmonic sequence.

Alternatively, in another embodiment of the present invention, the harmonic detecting means 410 may also output the obtained N-point harmonic sequence by N.

It will be appreciated that harmonic detection device 410, such as harmonic detection device 300, may have some or all of the functionality of harmonic detection device 300. The functions of the harmonic detecting device 410 can be specifically implemented according to the method in the foregoing method embodiments. For the specific implementation process, refer to the related description in the foregoing method embodiments, and details are not described herein again.

In some embodiments of the present invention, harmonic detection device 410 and electrical signal feedback device 420 in harmonic cancellation device 400 may be deployed, for example, in each of the power grid topologies shown in Figures 5a-5c to eliminate Harmonics.

To further illustrate the topology position and function of the harmonic elimination device 400 of the present invention, the following description uses the harmonic elimination device 400 as the APF/SVG as an example, combined with the parallel compensation harmonic current APF/SVG. It is to be noted that those skilled in the art will appreciate that the principles of the present invention for harmonic compensation in series or hybrid mode are equally applicable and are within the scope of the present invention.

See Figure 5b, Figure 5b is a schematic diagram of the parallel connection of APF/SVG compensation for reactive power and harmonic compensation. The nonlinear load is running in the grid, APF/SVG is connected in parallel to the grid, and the harmonics of the nonlinear load are applied. And reactive compensation. Where i _s (including i _Sa , i _sb , i _Sc ) is the supply current, (including iLa, iLb, ίΐ in the figure) is the load voltage 1Μ (including i]Ma, IMC) is the electrical signal feedback Device The compensation current generated by 420.

Referring to Figure 5c, the APF/SVG can detect harmonic components in the load current through the harmonic detecting means 410 therein. The harmonic detecting device 410 outputs a harmonic current sequence, and the reactive power detecting device 430 can calculate the load current fundamental wave reactive power by using the classical instantaneous reactive power theory calculation, output the reactive current sequence, and add the reactive current sequence and the harmonic current sequence. , get the reactive current sequence and harmonic current sequence to be compensated. The electrical signal feedback device 420 in FIG. 5c includes: a current controller 421, a DC voltage controller 422, and a power device 423 (such as an Insulated Gate Bipolar Transistor (IGBT)), wherein the current controller 421 and The harmonic detecting device 410, the reactive power detecting device 430, the DC voltage controller 422, and the power device 423 are connected, and the DC voltage controller 422 is also connected to the power device 423. The DC voltage controller 422 is mainly used to output a DC voltage adjustment signal. The current controller 421 is mainly configured to generate a pulse width modulation (PWM) signal output according to the reactive current sequence, the harmonic current sequence, and the DC voltage adjustment signal output by the DC voltage controller 422. The power device 423 is mainly used to generate a current signal output for compensating for harmonics and reactive power according to the PWM signal outputted by the current controller 421 to compensate the reactive and harmonic currents of the load. The compensation current i _M generated by the power device 423 (including i _Ma , i _Mb , i _{Mc in the} figure) can be equal to and equal to the harmonic component in the load current, so that the two can cancel each other, so that the power supply current only contains Basic active component.

The embodiment of the present invention further provides a computer storage medium, wherein the computer storage medium can store a program, and the program includes some or all of the steps of the data processing method described in the foregoing method embodiments. It should be noted that, for each of the foregoing method embodiments, for the description of the package, it is expressed as a series of action combinations, but those skilled in the art should know that the embodiments of the present invention are not subject to the described action sequence. Limitations, as certain steps may be performed in other orders or concurrently in accordance with embodiments of the present invention. In addition, those skilled in the art should also understand that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

In the above embodiments, the descriptions of the various embodiments are different, and the details are not described in detail in an embodiment, and the related descriptions of other embodiments can be referred to.

In summary, in the technical solution provided by the embodiment of the present invention, an electrical signal is sampled from a power line to obtain an N-point electrical signal sequence, and an N-point RFFT operation is performed to obtain a first complex sequence; The column performs harmonic extraction processing to obtain a second complex sequence; the second complex sequence is subjected to virtual and real combination processing to obtain a third complex sequence; the third complex sequence is subjected to RFFT operation to obtain a fourth complex sequence; and the fourth complex sequence is subjected to virtual and real combination Processing to obtain the N-point harmonic sequence, the scheme does not need to perform the conjugate operation before and after the FFT, and does not need the data extraction operation, but only needs to perform the virtual and real combination operations twice, that is, the addition and subtraction operation of the cartridge, so compared with the existing In terms of technology, the calculation time is saved, and the code space can be saved because the RFFT code can be fully utilized for calculation.

Further, no additional storage space is required, and the code space, the number of storage units, and the calculation time can be comprehensively optimized.

A person skilled in the art may understand that all or part of the various steps of the foregoing embodiments may be completed by a program instructing related hardware. The program may be stored in a computer readable storage medium, and the storage medium may include: Read-only memory, random access memory, disk or optical disk, etc.

The foregoing detailed description of a method for detecting harmonics and related devices provided by the embodiments of the present invention is only for helping to understand the method and core idea of the present invention. Meanwhile, for those skilled in the art, The present invention is not limited by the scope of the present invention.

Claims

Rights request

A harmonic detection method, characterized in that it comprises:

Sampling an electrical signal from a power line to obtain an electrical signal sequence at point N;

Performing a real-time fast Fourier transform of the N-point electrical signal sequence by an N-point RFFT operation to obtain a first complex sequence;

Performing harmonic extraction processing on the first complex sequence to obtain a second complex sequence;

Performing a virtual real combination process on the second complex sequence to obtain a third complex sequence;

Performing a real fast Fourier transform RFFT operation on the third complex sequence to obtain a fourth complex order 歹 ij ;

The fourth complex sequence is subjected to a virtual real combining process to obtain an N point harmonic sequence.

The harmonic detecting method according to claim 1, wherein the step of sampling the electrical signal from the power line to obtain the electrical signal sequence of the N point comprises:

During a signal fundamental period, electrical signals are sampled at equal intervals from the power line to obtain an electrical signal sequence at point N.

The harmonic detecting method according to claim 1, wherein the step of performing harmonic extraction processing on the first complex sequence to obtain a second complex sequence comprises:

Removing a fundamental component in the first complex sequence to obtain the second complex sequence; or

The method of detecting harmonics according to claim 1, wherein the step of performing a virtual-solid combination process on the second plurality of sequences comprises:

In the second complex sequence including the plurality of second complex numbers, each second complex number other than the data corresponding to the direct current component and the Nyquist frequency point is generated by the combination of the virtual and real processes a second complex number corresponding to the second complex number, wherein the real part of the third complex number is equal to the sum of the imaginary part coefficient and the real part corresponding to the second complex number, and the imaginary part coefficient of the third complex number is equal to the corresponding second complex number The difference between the real part and the imaginary part coefficient.

The method of detecting harmonics according to claim 1, wherein said said fourth complex The steps of performing the virtual and real combination processing on the sequence of numbers include:

In the fourth complex sequence including a plurality of fourth complex numbers, each fourth complex number other than the data corresponding to the direct current component and the Nyquist frequency point is generated by the combination of the virtual and real processing a sixth complex number corresponding to the fourth complex number, wherein the real part of the sixth complex number is equal to the sum of the imaginary part coefficient and the real part of the corresponding fourth complex number, and the imaginary part coefficient of the sixth complex number is equal to the corresponding fourth complex number The difference between the real part and the imaginary part coefficient.

The harmonic detecting method according to any one of claims 1 to 5, wherein the electric signal sequence of the N point is subjected to a real fast Fourier transform (RFFT) operation of N points to obtain a first complex sequence. The step includes: dividing the electrical signal sequence of the N point by the N, and performing an RFFT operation of the N point to obtain a first complex sequence;

Or,

The step of performing harmonic extraction processing on the first complex sequence to obtain the second complex sequence includes: performing harmonic extraction processing on the first complex sequence by dividing the N to obtain a second complex sequence;

Or,

The step of performing a virtual-real combination process on the second complex sequence to obtain a third complex sequence includes: after dividing the second complex sequence by the N, performing a virtual-real combination process to obtain a third complex sequence;

Or,

The harmonic detection method further includes:

Dividing the obtained N-point harmonic sequence by the stated

7. A harmonic detecting device, comprising:

a sampling unit, configured to sample an electrical signal from the power line to obtain an electrical signal sequence of N points; a first RFFT operation unit, configured to perform an N-point real fast Fourier transform of the electrical signal sequence of the N point obtained by the sampling unit The RFFT operation obtains the first complex sequence;

And a harmonic extraction unit, configured to perform harmonic extraction processing on the first complex sequence obtained by the first RFFT operation unit to obtain a second complex sequence;

a virtual and real combination processing unit, configured to perform a virtual combination process on the second complex sequence obtained by the harmonic extraction unit to obtain a third complex sequence;

a second RFFT operation unit, configured to perform an RFFT operation on the third complex sequence obtained by the virtual real processing unit to obtain a fourth complex sequence;

The virtual real processing unit is further configured to perform a virtual real combining process on the fourth complex sequence obtained by the second RFFT operation unit to obtain an N point harmonic sequence.

8. The harmonic detecting apparatus according to claim 7, wherein:

The virtual-real combination processing unit is specifically configured to: in the second complex sequence including the plurality of second complex numbers obtained by the harmonic extraction unit, except for the data corresponding to the direct current component and the Nyquist frequency point Each second complex number generates a third complex number corresponding to each of the second complex numbers by a combination of the virtual and real processes, wherein the real part of the third complex number is equal to the imaginary part coefficient and the real part corresponding to the second complex number And a sum of the imaginary part of the third complex number is equal to a difference between the real part and the imaginary part coefficient corresponding to the second complex number to obtain a third complex sequence including a plurality of third complex numbers.

The harmonic detecting apparatus according to claim 7, wherein the virtual real processing unit is further configured to: use, in the second RFFT operation unit, a fourth complex sequence including a plurality of fourth complex numbers a fourth complex number corresponding to each of the fourth complex numbers, wherein each of the fourth complex numbers other than the data corresponding to the direct current component and the Nyquist frequency point is generated by a combination of the virtual and real processes, wherein The real part of the sixth complex number is equal to the sum of the imaginary part coefficient and the real part corresponding to the fourth complex number, and the imaginary part coefficient of the sixth complex number is equal to the difference between the real part and the imaginary part coefficient corresponding to the fourth complex number to obtain a plurality of The sixth complex N-point harmonic sequence.

The harmonic detecting apparatus according to any one of claims 7 to 9, wherein the first RFFT operation unit is specifically configured to: the electric signal sequence of the N point obtained by the sampling unit After dividing the column by the N, performing an RFFT operation of N points to obtain a first complex sequence;

Or,

The harmonic extraction unit is specifically configured to: after the first complex sequence obtained by performing an RFFT operation on the first RFFT operation unit is divided by the N, perform harmonic extraction processing to obtain a second complex sequence;

Or,

11. A harmonic elimination device, comprising:

a harmonic detecting device, configured to sample an electrical signal from a power line to obtain an electrical signal sequence of N points; and perform a real-time fast Fourier transform RFFT operation of the N-point electrical signal sequence to obtain a first complex sequence; The first complex sequence is subjected to harmonic extraction processing to obtain a second complex sequence; the second complex sequence is subjected to a virtual real combination process to obtain a third complex sequence; and the third complex sequence is subjected to an RFFT operation to obtain a fourth complex sequence; Performing a virtual-solid combination process on the fourth complex sequence to obtain an N-point harmonic sequence and outputting;

12. A computer storage medium, characterized in that

The computer storage medium stores a program, and the program execution includes the steps of one of claims 1 to 6.