Multi-harmonic instantaneous extraction method, device and equipment based on FPGA (Field Programmable Gate Array) and medium

Abstract

The invention discloses a multi-harmonic instantaneous extraction method, device and equipment based on an FPGA and a medium, and the method comprises the steps: generating a conversion signal of an analog-to-digital conversion chip through a digital phase-locked loop of the FPGA, and fixing a sampling point of a unit power frequency period; capturing a completion signal of single analog quantity sampling of the analog-to-digital conversion chip in real time based on a main clock; reading an analog quantity sampling value, corresponding to the first storage unit, of the current address index; when the harmonic frequency is 2, sine and cosine values of the second storage unit and real and imaginary part values of the third storage unit are read based on the current address index and the harmonic frequency; new real part and imaginary part values are calculated and stored in a third storage unit; and obtaining a harmonic instantaneous value based on the new real part and imaginary part values and sine and cosine values, and when the target highest harmonic frequency is reached, updating the address index to wait for next sampling. The method is realized based on the logic gate and the storage unit of the FPGA, coordinate transformation is not needed, the method is suitable for harmonic detection of voltage or current of a single-phase or three-phase power system, and the real-time performance and the accuracy are high.

Description

Technical Field

[0001] The present invention relates to the technical field of power system harmonic detection, and in particular to an FPGA-based multi-harmonic instantaneous extraction method, device, equipment and medium. Background Art

[0002] With the rapid development of semiconductor technology and the country's strong support for renewable energy generation, more and more power electronic equipment are connected to the power grid, and the harmonic pollution of the power grid is becoming more and more serious. Therefore, the control of harmonics has always been the focus of research. Active power filter is a commonly used harmonic control method in power systems. The active power filter needs to extract the harmonic current from the object to be compensated, and then the compensation device outputs a compensation current of equal magnitude and opposite direction to make the total harmonic current zero, thereby achieving harmonic control. Therefore, the real-time and accuracy of the harmonic extraction algorithm will directly affect the effect of harmonic control.

[0003] Harmonic detection methods are mainly divided into time domain analysis methods based on instantaneous power theory and frequency domain analysis methods based on Fourier transform. The time domain analysis method based on instantaneous power theory is only applicable to three-phase systems and requires coordinate transformation, which is relatively complicated to implement. In the frequency domain analysis method, the traditional discrete Fourier transform has a large amount of calculation and a long calculation time, resulting in poor real-time performance of the calculation results. Although the fast Fourier transform simplifies the calculation process by combining the symmetric terms and similar terms in the discrete Fourier transform, it requires that the number of sampling points N must be an integer power of 2, and can only obtain the harmonics of all N frequencies at the same time, and cannot achieve selective harmonic extraction, and has poor flexibility. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned defects and problems existing in the prior art, and to provide a multi-harmonic instantaneous extraction method, device, equipment and medium based on FPGA, which is implemented based on FPGA logic gates and storage units, does not require coordinate transformation, and is suitable for harmonic detection of voltage or current in single-phase or three-phase power systems. When the sampling rate of the analog-to-digital conversion chip is sufficient, the instantaneous value from the fundamental wave to the ultra-high harmonic can be calculated after a single sampling is completed, and the real-time and accuracy are high.

[0005] To achieve the above objectives, the technical solution of the present invention is: a multi-harmonic instantaneous extraction method based on FPGA, comprising:

[0006] The conversion signal of the analog-to-digital conversion chip is generated through the digital phase-locked loop of the FPGA, and the sampling point of the unit power frequency cycle is fixed;

[0007] Capture the completion signal of a single analog quantity sampling of the analog-to-digital conversion chip in real time based on the main clock;

[0008] Read the analog quantity sampling value of the first storage unit corresponding to the current address index, and store the latest value in the first storage unit;

[0009] Starting from when the harmonic order is 2, the sine value and cosine value of the second storage unit and the real value and imaginary value of the third storage unit are read based on the current address index and the harmonic order;

[0010] Calculate new real value and imaginary value based on analog quantity sampling value, real value and imaginary value, sine value and cosine value, and store the new real value and imaginary value in a third storage unit of a corresponding address;

[0011] Obtaining the instantaneous value of the harmonic corresponding to the harmonic order based on the new real part value and imaginary part value as well as the sine value and cosine value;

[0012] Determine whether the harmonic order has reached the target highest harmonic order. If not, add 1 to the harmonic order and continue to obtain the instantaneous harmonic value of the corresponding harmonic order according to the above steps. If it has reached the target highest harmonic order, update the address index and wait for the next sampling.

[0013] The method of calculating new real value and imaginary value based on the analog quantity sampling value, the real value and imaginary value, and the sine value and cosine value comprises:

[0014] Calculate the analog sampling value x(n) per unit power frequency cycle:

[0015]

[0016] Where k is the harmonic order; N m is the harmonic with the highest frequency; N is the number of sampling points in a unit power frequency cycle; n is the sampling time; X real (k) is the real part value; X imag (k) is the imaginary part value; is the sine value; is the cosine value;

[0017] Real value X real (k) is:

[0018]

[0019] Imaginary value X imag (k) is:

[0020]

[0021] Assuming that the sampling values ​​of N sampling points before sampling time n are known, the real and imaginary values ​​are expressed as:

[0022]

[0023]

[0024] Similarly, we can get:

[0025]

[0026]

[0027] Then the real and imaginary values ​​are expressed as:

[0028]

[0029]

[0030] The instantaneous value of the harmonic corresponding to the harmonic order is:

[0031]

[0032] Where x(k, n) is the instantaneous value of the kth harmonic at sampling time n; real (k, n) is the real part value; X imag (k, n) is the imaginary part value; is the sine value; is the cosine value.

[0033] A multi-harmonic instantaneous extraction device based on FPGA, comprising:

[0034] The conversion signal generation module is used to generate the conversion signal of the analog-to-digital conversion chip through the digital phase-locked loop of the FPGA and fix the sampling point of the unit power frequency cycle;

[0035] A single sampling completion signal capture module is used to capture the completion signal of a single analog quantity sampling of the analog-to-digital conversion chip in real time based on the main clock;

[0036] A data reading module No. 1, used for reading the analog quantity sampling value of the first storage unit corresponding to the current address index, and storing the latest value in the first storage unit;

[0037] A second data reading module is used to read the sine value and cosine value of the second storage unit and the real value and imaginary value of the third storage unit based on the current address index and the harmonic order starting from when the harmonic order is 2;

[0038] A real value and imaginary value calculation module, used for calculating new real value and imaginary value based on the analog quantity sampling value, the real value and imaginary value, and the sine value and cosine value, and storing the new real value and imaginary value in a third storage unit of a corresponding address;

[0039] The harmonic instantaneous value acquisition module is used to obtain the harmonic instantaneous value of the corresponding harmonic order based on the new real value and imaginary value and the sine value and cosine value; and to determine whether the harmonic order has reached the target maximum harmonic order. If not, the harmonic order is increased by 1, and the harmonic instantaneous value of the corresponding harmonic order is obtained according to the above steps; if it has been reached, the address index is updated and wait for the next sampling.

[0040] The method of calculating new real value and imaginary value based on the analog quantity sampling value, the real value and imaginary value, and the sine value and cosine value comprises:

[0041] Calculate the analog sampling value x(n) per unit power frequency cycle:

[0042]

[0043] Where k is the harmonic order; N m is the harmonic with the highest frequency; N is the number of sampling points in a unit power frequency cycle; n is the sampling time; X real (k) is the real part value; X imag (k) is the imaginary part value; is the sine value; is the cosine value;

[0044] Real value X real (k) is:

[0045]

[0046] Imaginary value X imag (k) is:

[0047]

[0048] Assuming that the sampling values ​​of N sampling points before sampling time n are known, the real and imaginary values ​​are expressed as:

[0049]

[0050]

[0051] Similarly, we can get:

[0052]

[0053]

[0054] Then the real and imaginary values ​​are expressed as:

[0055]

[0056]

[0057] The instantaneous value of the harmonic corresponding to the harmonic order is:

[0058]

[0059] Where x(k, n) is the instantaneous value of the kth harmonic at sampling time n; real (k, n) is the real part value; X imag (k, n) is the imaginary part value; is the sine value; is the cosine value.

[0060] A multi-harmonic instantaneous extraction device based on FPGA, comprising a memory and a processor;

[0061] The memory is used to store computer program code and transmit the computer program code to the processor;

[0062] The processor is used to execute the method according to the instructions in the computer program code.

[0063] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method described above is implemented.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The present invention discloses an FPGA-based multi-harmonic instantaneous extraction method, device, equipment and medium. The method is implemented based on FPGA logic gates and storage units without coordinate transformation, and is suitable for harmonic detection of voltage or current in single-phase or three-phase power systems. The method has no requirement on the number of sampling points and can realize selective harmonic extraction with high flexibility. When the sampling rate of an analog-to-digital conversion chip is sufficient, the instantaneous value from fundamental wave to ultra-high harmonic can be calculated after a single sampling is completed, and the method has high real-time performance and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 The present invention is a flowchart of a multi-harmonic instantaneous extraction method based on FPGA.

[0067] Figure 2 It is a structural block diagram of a multi-harmonic instantaneous extraction device based on FPGA of the present invention.

[0068] Figure 3 It is a structural block diagram of a multi-harmonic instantaneous extraction device based on FPGA of the present invention. DETAILED DESCRIPTION

[0069] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0070] See also Figure 1 , a multi-harmonic instantaneous extraction method based on FPGA, comprising:

[0071] S1, generate the conversion signal of the analog-to-digital conversion chip through the digital phase-locked loop of the FPGA, and fix the sampling point of the unit power frequency cycle;

[0072] S2, based on the system master clock, real-time capture of the completion signal of a single analog quantity sampling of the analog-to-digital conversion chip;

[0073] S3, reading the analog quantity sampling value of the first storage unit corresponding to the current address index, and storing the latest value in the first storage unit;

[0074] S4, starting from when the harmonic order is 2, read the sine value and cosine value (i.e., sine-cosine table) of the second storage unit and the real value and imaginary value of the third storage unit based on the current address index and the harmonic order;

[0075] S5, calculating new real part value and imaginary part value based on the analog quantity sampling value, the real part value and the imaginary part value, and the sine value and the cosine value, and storing the new real part value and the imaginary part value in a third storage unit at a corresponding address;

[0076] S6. Obtaining the instantaneous value of the harmonic corresponding to the harmonic order based on the new real part value and imaginary part value as well as the sine value and cosine value;

[0077] S7. Determine whether the harmonic order has reached the target maximum harmonic order. If not, add 1 to the harmonic order and continue to follow the above steps (steps S4 to S6) to obtain the instantaneous harmonic value of the corresponding harmonic order. If it has reached the target maximum harmonic order, update the address index and wait for the next sampling.

[0078] Further, the calculating of new real value and imaginary value based on the analog quantity sampling value, the real value and the imaginary value, and the sine value and the cosine value includes:

[0079] Calculate the analog sampling value x(n) per unit power frequency cycle:

[0080]

[0081] Where k is the harmonic order; N m is the harmonic with the highest frequency; N is the number of sampling points in a unit power frequency cycle; n is the sampling time; X real (k) is the real part value; X imag (k) is the imaginary part value; is the sine value; is the cosine value;

[0082] Real value X real (k) is:

[0083]

[0084] Imaginary value X imag (k) is:

[0085]

[0086] Assuming that the sampling values ​​of N sampling points before sampling time n are known, the real and imaginary values ​​are expressed as:

[0087]

[0088]

[0089] Similarly, we can get:

[0090]

[0091]

[0092] Then the real and imaginary values ​​are expressed as:

[0093]

[0094]

[0095] Through the above calculation method, it is only necessary to calculate the analog sampling values ​​x(n) and x(nN) obtained in step S3 and the sine value obtained in step S4. and cosine and the old real value X real (k, n-1) and the imaginary value X imag (k, n-1), you can get the new real and imaginary part values.

[0096] Furthermore, the instantaneous value of the harmonic corresponding to the harmonic order is:

[0097]

[0098] Where x(k, n) is the instantaneous value of the kth harmonic at sampling time n; real (k, n) is the real part value; X imag (k, n) is the imaginary part value; is the sine value; is the cosine value.

[0099] See also Figure 2 , a multi-harmonic instantaneous extraction device based on FPGA, comprising:

[0100] The conversion signal generation module is used to generate the conversion signal of the analog-to-digital conversion chip through the digital phase-locked loop of the FPGA and fix the sampling point of the unit power frequency cycle;

[0101] A single sampling completion signal capture module is used to capture the completion signal of a single analog quantity sampling of the analog-to-digital conversion chip in real time based on the main clock;

[0102] A data reading module No. 1, used for reading the analog quantity sampling value of the first storage unit corresponding to the current address index, and storing the latest value in the first storage unit;

[0103] A second data reading module is used to read the sine value and cosine value of the second storage unit and the real value and imaginary value of the third storage unit based on the current address index and the harmonic order starting from when the harmonic order is 2;

[0104] A real value and imaginary value calculation module, used for calculating new real value and imaginary value based on the analog quantity sampling value, the real value and imaginary value, and the sine value and cosine value, and storing the new real value and imaginary value in a third storage unit of a corresponding address;

[0105] The harmonic instantaneous value acquisition module is used to obtain the harmonic instantaneous value of the corresponding harmonic order based on the new real value and imaginary value and the sine value and cosine value; and to determine whether the harmonic order has reached the target maximum harmonic order. If not, the harmonic order is increased by 1, and the harmonic instantaneous value of the corresponding harmonic order is obtained according to the above steps; if it has been reached, the address index is updated and wait for the next sampling.

[0106] Further, the calculating of new real value and imaginary value based on the analog quantity sampling value, the real value and the imaginary value, and the sine value and the cosine value includes:

[0107] Calculate the analog sampling value x(n) per unit power frequency cycle:

[0108]

[0109] Where k is the harmonic order; N m is the harmonic with the highest frequency; N is the number of sampling points in a unit power frequency cycle; n is the sampling time; X real (k) is the real part value; X imag (k) is the imaginary part value; is the sine value; is the cosine value;

[0110] Real value X real (k) is:

[0111]

[0112] Imaginary value X imag (k, n) is:

[0113]

[0114] Assuming that the sampling values ​​of N sampling points before sampling time n are known, the real and imaginary values ​​are expressed as:

[0115]

[0116]

[0117] Similarly, we can get:

[0118]

[0119]

[0120] Then the real and imaginary values ​​are expressed as:

[0121]

[0122]

[0123] Furthermore, the instantaneous value of the harmonic corresponding to the harmonic order is:

[0124]

[0125] Where x(k, n) is the instantaneous value of the kth harmonic at sampling time n; real (k, n) is the real part value; X imag (k, n) is the imaginary part value; is the sine value; is the cosine value.

[0126] See also Figure 3 ,The present invention also provides a multi-harmonic instantaneous extraction device based on FPGA, including a memory and a processor;

[0127] The memory is used to store computer program code and transmit the computer program code to the processor;

[0128] The processor is used to execute the above-mentioned FPGA-based multi-harmonic instantaneous extraction method according to the instructions in the computer program code.

[0129] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the FPGA-based multi-harmonic instantaneous extraction method described above is implemented.

[0130] Generally speaking, the computer instructions for implementing the method of the present invention may be carried in any combination of one or more computer-readable storage media. Non-transitory computer-readable storage media may include any computer-readable media, except for the signal itself that is temporarily propagating.

[0131] The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EKROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in conjunction with an instruction execution system, device, or device.

[0132] Computer program code for performing the operation of the present invention can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages, in particular, Python suitable for neural network computing and platform frameworks based on TensorFlow, PyTorch, etc. can be used. The program code can be executed entirely on the user's computer, partially on the user's computer, as an independent software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer or to an external computer (for example, using an Internet service provider to connect via the Internet) through any type of network, including a local area network (LAN) or a wide area network (WAN).

[0133] The above-mentioned device and non-temporary computer-readable storage medium can be found in the detailed description of a multi-harmonic instantaneous extraction method based on FPGA and its beneficial effects, which will not be repeated here.

[0134] Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A multi-harmonic instantaneous extraction method based on FPGA, characterized in that: include: The conversion signal of the analog-to-digital conversion chip is generated through the digital phase-locked loop of the FPGA, and the sampling point of the unit power frequency cycle is fixed; Capture the completion signal of a single analog quantity sampling of the analog-to-digital conversion chip in real time based on the main clock; Read the analog quantity sampling value of the first storage unit corresponding to the current address index, and store the latest value in the first storage unit; Starting from when the harmonic order is 2, the sine value and cosine value of the second storage unit and the real value and imaginary value of the third storage unit are read based on the current address index and the harmonic order; Calculate new real value and imaginary value based on analog quantity sampling value, real value and imaginary value, sine value and cosine value, and store the new real value and imaginary value in a third storage unit of a corresponding address; Obtaining the instantaneous value of the harmonic corresponding to the harmonic order based on the new real part value and imaginary part value as well as the sine value and cosine value; Determine whether the harmonic order has reached the target highest harmonic order. If not, add 1 to the harmonic order and continue to obtain the instantaneous harmonic value of the corresponding harmonic order according to the above steps. If it has reached the target highest harmonic order, update the address index and wait for the next sampling.

2. The FPGA-based multi-harmonic instantaneous extraction method according to claim 1 is characterized in that: The method of calculating new real value and imaginary value based on the analog quantity sampling value, the real value and imaginary value, and the sine value and cosine value comprises: Calculate the analog sampling value x(n) per unit power frequency cycle: Where k is the harmonic order; N m is the harmonic with the highest frequency; N is the number of sampling points in a unit power frequency cycle; n is the sampling time; X real (k) is the real part value; X imag (k) is the imaginary part value; is the sine value; is the cosine value; Real value X real (k) is: Imaginary value X imag (k) is:

3. The FPGA-based multi-harmonic instantaneous extraction method according to claim 2 is characterized in that: Assuming that the sampling values ​​of N sampling points before sampling time n are known, the real and imaginary values ​​are expressed as: Similarly, we can get: Then the real and imaginary values ​​are expressed as:

4. The FPGA-based multi-harmonic instantaneous extraction method according to claim 3 is characterized in that: The instantaneous value of the harmonic corresponding to the harmonic order is: Where x(k, n) is the instantaneous value of the kth harmonic at sampling time n; X real (k, n) is the real part value; X imag (k, n) is the imaginary part value; is the sine value; is the cosine value.

5. A multi-harmonic instantaneous extraction device based on FPGA, characterized in that: include: The conversion signal generation module is used to generate the conversion signal of the analog-to-digital conversion chip through the digital phase-locked loop of the FPGA and fix the sampling point of the unit power frequency cycle; A single sampling completion signal capture module is used to capture the completion signal of a single analog quantity sampling of the analog-to-digital conversion chip in real time based on the main clock; A data reading module No. 1, used for reading the analog quantity sampling value of the first storage unit corresponding to the current address index, and storing the latest value in the first storage unit; A second data reading module is used to read the sine value and cosine value of the second storage unit and the real value and imaginary value of the third storage unit based on the current address index and the harmonic order starting from when the harmonic order is 2; A real value and imaginary value calculation module, used for calculating new real value and imaginary value based on the analog quantity sampling value, the real value and imaginary value, and the sine value and cosine value, and storing the new real value and imaginary value in a third storage unit of a corresponding address; The harmonic instantaneous value acquisition module is used to obtain the harmonic instantaneous value of the corresponding harmonic order based on the new real value and imaginary value and the sine value and cosine value; and to determine whether the harmonic order has reached the target maximum harmonic order. If not, the harmonic order is increased by 1, and the harmonic instantaneous value of the corresponding harmonic order is obtained according to the above steps; if it has been reached, the address index is updated and wait for the next sampling.

6. The FPGA-based multi-harmonic instantaneous extraction device according to claim 5, characterized in that: The method of calculating new real value and imaginary value based on the analog quantity sampling value, the real value and imaginary value, and the sine value and cosine value comprises: Calculate the analog sampling value x(n) per unit power frequency cycle: Where k is the harmonic order; N m is the harmonic with the highest frequency; N is the number of sampling points in a unit power frequency cycle; n is the sampling time; X real (k) is the real part value; X imag (k) is the imaginary part value; is the sine value; is the cosine value; Real value X real (k) is: Imaginary value X imag (k, n) is:

7. The FPGA-based multi-harmonic instantaneous extraction device according to claim 5, characterized in that: Assuming that the sampling values ​​of N sampling points before sampling time n are known, the real and imaginary values ​​are expressed as: Similarly, we can get: Then the real and imaginary values ​​are expressed as:

8. The FPGA-based multi-harmonic instantaneous extraction device according to claim 5, characterized in that: The instantaneous value of the harmonic corresponding to the harmonic order is: Where x(k, n) is the instantaneous value of the kth harmonic at sampling time n; X real (k, n) is the real part value; X imag (k, n) is the imaginary part value; is the sine value; is the cosine value.

9. A multi-harmonic instantaneous extraction device based on FPGA, characterized in that: including memory and processor; The memory is used to store computer program code and transmit the computer program code to the processor; The processor is configured to execute the method according to any one of claims 1 to 4 according to instructions in the computer program code.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 4 is implemented.

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