Phasor correction method and device, computer equipment and program product

Abstract

The invention is applicable to the technical field of power system frequency measurement, and provides a phasor correction method and device, computer equipment and a program product, and the method comprises the steps: for three continuous sampling points, combining real part functions and imaginary part functions of the three sampling points to obtain a first expression about system frequency and real part values of the three sampling points, the first expression is about the system frequency and the imaginary part values of the three sampling points, and the second expression is about the system frequency and the imaginary part values of the three sampling points, and the first expression and the second expression are integrated according to a similar proportion principle to obtain a calculation formula of the system frequency; calculating the current system frequency by using the real part values and imaginary part values of the three sampling points and a calculation formula of the system frequency; and calculating a real part correction coefficient and an imaginary part correction coefficient based on the average frequency favg and the reference frequency f0 in a period of time, and correcting the real part function and the imaginary part function of the sampling point according to the real part correction coefficient and the imaginary part correction coefficient. Therefore, the system frequency can be accurately and efficiently calculated, and the system phasor is corrected.

Description

Technical Field

[0001] The present application belongs to the technical field of power system frequency measurement, and in particular, to a phasor correction method, device, computer equipment and program product. Background Art

[0002] Frequency is an important parameter in the power system and an important criterion for measuring the power quality of the power system. In recent years, with the rapid development of power technology, the installed capacity of new energy power plants (wind farms and photovoltaic power plants) has gradually increased, and the safe and stable operation of grid-connected new energy power plants and the regional power grids they are connected to has received increasing attention. Frequency, as an important criterion for measuring power quality, has received more widespread attention. Due to the commissioning of many nonlinear electrical equipment, the voltage and current waveforms of the power grid are distorted into non-sinusoidal waves, and there are a large number of harmonic components. When the harmonic content of the system reaches a certain level, it will cause damage to the normal operation of the power system. Therefore, accurately measuring the frequency value of the real-time operation of the power system and correcting the phase based on the frequency value are of great significance to ensure the stable operation of the power system. Summary of the invention

[0003] The embodiments of the present application provide a phasor correction method, apparatus, computer equipment and program product, which can accurately and efficiently calculate the frequency magnitude in the system and adjust the system phasor.

[0004] In a first aspect, an embodiment of the present application provides a phasor correction method, comprising:

[0005] For three consecutive sampling points of the AC voltage, the real and imaginary functions of the three sampling points are combined to obtain the real value U of the three sampling points related to the system frequency. R(k-1) , U Rk , U R(k+1) The first expression of, and the imaginary value U of the system frequency and the three sampling points I(k-1) , U Ik , U I(k+1) The second expression of is obtained by integrating the first expression and the second expression according to the principle of similar proportion to obtain the calculation formula of the system frequency;

[0006] The current system frequency is calculated using the real and imaginary values ​​of the three sampling points and the calculation formula of the system frequency;

[0007] Based on the average value of the frequency over a period of time f avg , reference frequency f 0 The real part correction coefficient and the imaginary part correction coefficient are calculated, and the real part function and the imaginary part function of the sampling point are corrected according to the real part correction coefficient and the imaginary part correction coefficient.

[0008] In a possible implementation manner of the first aspect, the first expression includes the real part values ​​U of the three sampling points R(k-1) , U Rk , U R(k+1) and The second expression above includes the imaginary values ​​U of the three sampling points I(k-1) , U Ik , U I(k+1) and Among them, T 0 is the sampling period, and N is the total number of sampling points.

[0009] Specifically, the first expression above is:

[0010]

[0011] The second expression above is:

[0012]

[0013] Specifically, the calculation formula of the above system frequency is as follows:

[0014]

[0015] In another implementation, the calculation formula of the above system frequency is as follows:

[0016]

[0017] Where n is the size of the calculation window, and the upper limit of n is N / 8.

[0018] Specifically, the real part correction coefficient is:

[0019]

[0020] The above imaginary correction coefficient is:

[0021]

[0022] in,

[0023] Exemplarily, the real part function with the correction coefficient is:

[0024]

[0025] The imaginary function with correction coefficient is:

[0026]

[0027] Where Δf is the frequency deviation.

[0028] In a second aspect, an embodiment of the present application provides a phasor correction device, including:

[0029] The frequency calculation module is used to combine the real and imaginary functions of the three consecutive sampling points of the AC voltage to obtain the real value U of the system frequency and the three sampling points. R(k-1) , U Rk , U R(k+1) The first expression of, and the imaginary value U of the system frequency and the three sampling points I(k-1) , U Ik , U I(k+1) The second expression of is used to integrate the first expression and the second expression according to the similar proportion principle to obtain a calculation formula for the system frequency; the current system frequency is calculated using the real part values, imaginary part values ​​of the three sampling points and the calculation formula for the system frequency;

[0030] Phase correction module, used to calculate the average value of the frequency f over a period of time avg , reference frequency f 0 The real part correction coefficient and the imaginary part correction coefficient are calculated, and the real part function and the imaginary part function of the sampling point are corrected according to the real part correction coefficient and the imaginary part correction coefficient.

[0031] In a third aspect, an embodiment of the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method described in any one of the first aspects is implemented.

[0032] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, comprising: the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in the method described in any one of the first aspects are implemented.

[0033] In a fifth aspect, an embodiment of the present application provides a computer program product. When the computer program product is run on a computer device, the computer device executes any method described in the first aspect above.

[0034] It can be understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0035] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0036] This application uses the real and imaginary part sampling values ​​of the "three-point" AC voltage and the principle of similar proportion to solve the frequency in the power system, which can accurately and efficiently calculate the system frequency. It has the advantages of small overall algorithm calculation, fast response speed, and high applicability, which can shorten the measurement cycle and take into account both instantaneity and accuracy. In addition, using the calculated system frequency for phasor correction can improve the stability of system operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 is a flow chart of a phasor correction method provided by an embodiment of the present application;

[0039] Figure 2 is a structural schematic diagram of a phasor correction device provided in one embodiment of the present application;

[0040] Figure 3 It is a structural diagram of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0041] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0042] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0043] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0044] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0045] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0046] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0047] At present, frequency measurement methods in power systems are mainly divided into two categories, namely hardware-based measurement and algorithm-based measurement, considering simplicity and real-time performance.

[0048] (1) Hardware-based measurement method

[0049] There are two main commonly used hardware measurement methods. One is to use a measurement tool composed of a zero-crossing comparator, a square wave forming circuit and a counter. This method uses the system's period and frequency calculation to directly measure the frequency. The other is to use a phase-locked frequency multiplication circuit to track the system frequency online. This method combines the functions of a phase-locked loop (PLL) and a frequency multiplier. It is a circuit that can automatically adjust the output signal frequency and phase to keep it synchronized with the input signal. These two hardware-based methods rely on the role of peripheral circuits and do not occupy processor time. However, for the newly added external frequency measurement circuit, both require the use of the computer's external interrupt port, and the external device is easily affected by external factors, which poses certain challenges and complexities to hardware design.

[0050] (2) Algorithm-based measurement method

[0051] The algorithmic frequency measurement method uses the obtained discrete values, peak detection, cumulative summation and cycle calculation methods to measure the sampling frequency, and then adjusts the sampling interval to timely achieve that the N sampling points of each cycle are evenly distributed in each power frequency cycle. Compared with the hardware-based measurement method, this method does not require hardware circuit design, the calculation is simple and convenient, and it is easy to implement. However, it takes a certain amount of processor calculation time. Traditional algorithm-based measurement methods include voltage zero-crossing method, interpolation-based CROSS method, least squares method, Kalman filter method and Fourier transform-based method. Most of these methods have large calculation amounts, cannot suppress harmonic components well, and cannot unify calculation accuracy and calculation speed well, which will affect practical applications.

[0052] The method often used in power system protection and measurement and control is the Fourier algorithm, which calculates the spectrum of the signal and finds the component corresponding to the fundamental frequency to obtain the system frequency. It is widely used because of its inherent insensitivity to the large time lag of harmonic components and its high precision and fast response. The following is the process of the traditional Fourier frequency measurement algorithm:

[0053] The analog quantity in the known system is shown in formula (1), where f 0 The power frequency is 50Hz, The initial phase.

[0054]

[0055] In the process of Fourier calculation formula, since the frequency deviation Δf is unknown, the Fourier algorithm can only use the power frequency orthogonal function to calculate. The function formula of the full-cycle Fourier calculation of the real and imaginary parts. First, set the orthogonal basis sin(2πf 0 t) and cos(2πf 0 t), then the real and imaginary orthogonal functions are u r (t)=u(t)sin(2πf 0 t) and u i (t) = u(t)cos(2πf 0 t). The integral formulas for calculating the real and imaginary parts are shown in formulas (2) and (3) respectively:

[0056]

[0057]

[0058] The real and imaginary part functions are shown in formulas (4) and (5):

[0059]

[0060] If the sampling point is N sampling intervals per cycle, then N sampling points can be used. As shown in formula (6):

[0061]

[0062] After time series calculation, we can get the following equation (7):

[0063]

[0064] Then calculate the system frequency using equations (8), (9), and (10).

[0065]

[0066] (3) Analysis of traditional frequency measurement methods

[0067] In the traditional frequency measurement method, the hardware-based method uses the hardware equipment of the peripheral circuit to measure the frequency during the frequency measurement process. Although it does not take up the processor time, it has certain challenges for the overall hardware design. It needs to occupy the external interrupt port of the computer, and is easily affected by the zero drift and harmonics of the device. The real-time performance cannot be guaranteed, which is not convenient enough. The algorithm-based frequency measurement method has been more commonly used in recent years, but most of these methods have the problems of large amount of calculation, lack of real-time performance, and relatively complex algorithms. Nowadays, the most commonly used frequency measurement method is still the method based on Fourier transform, which is widely used based on its own simple calculation and inherent insensitivity to harmonics. However, when the traditional Fourier transform method uses fixed frequency sampling or the sampling frequency cannot track the system frequency well, the calculation error will be large. And when the system frequency deviates greatly from the rated frequency, the frequency calculation error will also be relatively large.

[0068] In summary, the current traditional frequency measurement methods mainly have the following problems:

[0069] 1) In the actual frequency measurement process, it is easily affected by external and harmonic frequencies, and when the system frequency deviates greatly from the rated frequency, the frequency calculation error is large;

[0070] 2) For sudden changes in phase and frequencies with large fluctuations, the sudden changes cannot be detected in a timely and accurate manner, resulting in large errors in frequency calculation;

[0071] 3) For algorithms with large computational complexity, the frequency measurement cycle is long, which affects the response speed and real-time performance of the frequency measurement.

[0072] In response to the above problems, the present application provides a phasor correction method, which is based on a new fast and high-precision frequency measurement method to achieve fast measurement of system frequency, and use the measured system frequency to perform phasor correction on the real and imaginary part function, taking into account both instantaneousness and accuracy, and has high applicability. Among them, the new fast and high-precision frequency measurement method uses the real and imaginary part information of three AC voltage sampling points to calculate the system frequency according to the principle of similar proportions. It has the advantages of small calculation amount, fast response speed, and strong applicability. It is more effective and accurate for the frequency measurement of new energy stations, can shorten the measurement cycle, and takes into account both instantaneousness and accuracy.

[0073] The technical solutions in the embodiments of the present application are described in detail below.

[0074] Figure 1 : is a flow chart of a phasor correction method provided by an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0075] Step 101, calculate the current system frequency using the real part value, imaginary part value of three consecutive sampling points of the AC voltage and the calculation formula of the system frequency.

[0076] In one embodiment, the real function and the imaginary function of the sampling point can be obtained by using the Fourier transform algorithm to determine the orthogonal basis sin(2πf 0 t) and cos(2πf 0 t); Use the Fourier transform algorithm to determine the orthogonal function u of the AC voltage r (t)=u(t)sin(2πf 0 t) and u i (t) = u(t)cos(2πf 0 t); the calculation formula of the real and imaginary part function is obtained by Fourier transform algorithm.

[0077] In one embodiment, the calculation formula of the system frequency can be obtained by the following method:

[0078] For three consecutive sampling points of the AC voltage, the real and imaginary functions of the three sampling points are combined to obtain the real value U of the three sampling points related to the system frequency. R(k-1) , U Rk , U R(k+1) The first expression of, and the imaginary value U of the system frequency and the three sampling points I(k-1) , U Ik , U I(k+1)The second expression of is obtained by integrating the first expression and the second expression according to the principle of similar proportion, and the calculation formula of the system frequency is obtained. Among them, the principle of similar proportion means that the corresponding physical quantities of all the phenomena characterized at the corresponding points at the corresponding instants maintain their respective fixed proportional relationships.

[0079] In one example, the first expression includes the real value U of three sampling points R(k-1) , U Rk , U R(k+1) and The second expression includes the imaginary values ​​U of the three sampling points I(k-1) , U Ik , U I(k+1) and Among them, T 0 is the sampling period, and N is the total number of sampling points.

[0080] The specific system frequency calculation formula will be described in detail later and will not be repeated here.

[0081] Step 102, calculating a real correction coefficient and an imaginary correction coefficient based on an average value of the frequency within a period of time and a reference frequency, and correcting the real function and the imaginary function of the sampling point according to the real correction coefficient and the imaginary correction coefficient.

[0082] The average value of the frequency over a period of time can be expressed as f avg The reference frequency is f 0 .

[0083] After the system frequency is obtained based on step 101, considering the integrity of the phase information of the real and imaginary functions and the accuracy of the spectrum characteristic analysis, in order to avoid the occurrence of signal distortion and adapt to practical applications, the phasor correction operation of the real and imaginary functions can be performed through step 102, which can not only ensure the integrity of the signal phase information, but also improve the accurate analysis of the spectrum characteristics, avoid signal distortion and meet the needs in practical applications.

[0084] The three-point frequency measurement method in step 101 can be used to obtain the frequency values ​​corresponding to all sampling points within a period of time. In order to reduce the error, a phasor correction is performed based on the obtained frequency. In one embodiment, the average value of the frequency within a period of time f avg It can be obtained in the following way: The average frequency over a period of time is obtained by the three-point frequency measurement method. The specific calculation formula is: in If N is 48, the average value of the 24 consecutive frequency values ​​is used as f avg .

[0085] So far, the Figure 1 Description of the process shown.

[0086] Figure 1 The process shown uses the real and imaginary part sampling values ​​of the "three-point" AC voltage and the principle of similar proportion to solve the frequency in the power system, which can accurately and efficiently calculate the system frequency. It has the advantages of small overall algorithm calculation, fast response speed, and high applicability, which can shorten the measurement cycle and take into account both instantaneousness and accuracy. In addition, using the calculated system frequency for phasor correction can improve the stability of system operation.

[0087] The following is an example of the system frequency calculation in step 101 above:

[0088] Step 101 is to solve based on the real and imaginary numerical information of the three selected continuous sampling points. Specifically, the solution is obtained through the following calculation process.

[0089] In one example, the real part and imaginary part function expressions of the analog quantity obtained by Fourier transform are shown in equations (11) and (12):

[0090]

[0091] make Then the real part and imaginary part functions can be simplified as formula (13) and (14):

[0092]

[0093] Substitute the information of the sampling points on both sides into the real part function and then add them together to obtain formula (15):

[0094]

[0095] By calculation, formula (15) can be organized as shown in formula (16):

[0096]

[0097] Simplifying formula (16) yields formula (17):

[0098]

[0099] Formula (18) can be obtained by transforming formula (17), which is the first expression described in the above embodiment:

[0100]

[0101] Similarly, for the calculation of the imaginary function, the information of the sampling points on both sides is substituted into the function expression of the imaginary part, and after the addition operation, it is simplified as shown in formula (19):

[0102]

[0103] Transforming formula (19) yields formula (20), which is the second expression described in the above embodiment:

[0104]

[0105] According to the principle of similar proportion, integrating formula (18) and (20), we can get formula (21):

[0106]

[0107] By rearranging formula (21), we can get formula (22), which is the calculation formula for the system frequency f:

[0108]

[0109] Wherein, a refers to arc, which is the abbreviation of inverse trigonometric function, and acos refers to inverse cosine function. For example, if cos(a)=b, then arccos(b)=a. a in formulas (21), (22), (24), and (30) has the same meaning.

[0110] Based on the frequency measurement based on three consecutive sampling points, the calculation window of this method can be extended. The system frequency calculation after the window extension can be expressed as shown in formula (23):

[0111]

[0112] When n approaches N, the value of N / n will be smaller, the influence of the calculation error of arccosine on the result will be smaller, and the accuracy of the measured system frequency will be higher. However, due to the limitation of the sum-difference-product formula, the difference between the two angles cannot be greater than 90 degrees, so n cannot approach N infinitely, and the upper limit of n is N / 8. Therefore, based on formula (23), if a 48-point sampling method is used, that is, N=48, the value of the calculation window n is 6. When n is 6, the system frequency calculation formula is shown in formula (24):

[0113]

[0114] Where i is the current moment. The result of the calculation by this formula is smooth and can be processed by mean filtering. The calculation is simple, the effect is good, and the calculation accuracy is high.

[0115] The following is an example of the phase correction in step 102 above:

[0116] After the system frequency is obtained in step 101, in one embodiment, the real correction coefficient and the imaginary correction coefficient may be calculated in the following manner:

[0117] f avgis the average frequency over a period of time, let Then we can get formula (25):

[0118]

[0119] Furthermore, the real and imaginary correction coefficients can be obtained as shown in equations (26) and (27):

[0120]

[0121] for Function, since the curve is constant, can be fixed by a table.

[0122] After obtaining the correction coefficient, the real and imaginary functions with the correction coefficient can be expressed as shown in equations (28) and (29):

[0123]

[0124] The corrected phase angle is shown in formula (30):

[0125]

[0126] At this point, the description of the phasor correction method provided by the present application is completed.

[0127] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0128] Corresponding to the phasor correction method described in the above embodiment, Figure 2 A structural block diagram of a phasor correction device provided in an embodiment of the present application is shown. For ease of explanation, only the parts related to the embodiment of the present application are shown.

[0129] Reference Figure 2 The device comprises: a frequency calculation module 201 and a phase correction module 202. Wherein:

[0130] The frequency calculation module 201 is used to combine the real part function and the imaginary part function of the three sampling points for the AC voltage to obtain the real part value U of the system frequency and the three sampling points. R(k-1) , U Rk , U R(k+1) The first expression of, and the imaginary value U of the system frequency and the three sampling points I(k-1) , U Ik , U I(k+1)The second expression of is used to integrate the first expression and the second expression according to the principle of similar proportion to obtain the calculation formula of the system frequency; the current system frequency is calculated using the real part value, the imaginary part value of the three sampling points and the calculation formula of the system frequency;

[0131] The phase correction module 202 is used to calculate the average value of the frequency f within a period of time. avg and reference frequency f 0 The real correction coefficient and the imaginary correction coefficient are calculated, and the real function and the imaginary function of the sampling point are corrected according to the real correction coefficient and the imaginary correction coefficient.

[0132] It should be noted that the information interaction, execution process, etc. between the above-mentioned devices / units / modules are based on the same concept as the method embodiment of the present application. Their specific functions and technical effects can be found in the method embodiment part and will not be repeated here.

[0133] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0134] An embodiment of the present application also provides a computer device, which includes: at least one processor, a memory, and a computer program stored in the memory and executable on the at least one processor, wherein the processor implements the steps of any of the above-mentioned method embodiments when executing the computer program.

[0135] An embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps in the above-mentioned method embodiments can be implemented.

[0136] An embodiment of the present application provides a computer program product. When the computer program product is run on a computer device, the computer device can implement the steps in the above-mentioned method embodiments when executing the computer device.

[0137] Figure 3 This is a schematic diagram of the structure of a computer device provided in one embodiment of the present application. Figure 3 As shown, the computer device of this embodiment includes: at least one processor 30 ( Figure 3 Only one is shown), a memory 31, and a computer program 32 stored in the memory 31 and executable on the at least one processor 30, wherein the processor 30 implements the steps of any of the above-mentioned visual programming method embodiments when executing the computer program 32.

[0138] The computer device may include, but is not limited to, a processor 30 and a memory 31. Those skilled in the art will appreciate that Figure 3 It is only an example of a computer device and does not constitute a limitation of the computer device. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, it may also include input and output devices, network access devices, etc.

[0139] The processor 30 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0140] In some embodiments, the memory 31 may be an internal storage unit of the computer device, such as a hard disk or memory of the computer device. In other embodiments, the memory 31 may also be an external storage device of the computer device, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the computer device. Further, the memory 31 may also include both an internal storage unit of the computer device and an external storage device. The memory 31 is used to store an operating system, an application program, a boot loader (BootLoader), data, and other programs, such as the program code of the computer program. The memory 31 may also be used to temporarily store data that has been output or is to be output.

[0141] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device that can carry the computer program code to the device / computer device, a recording medium, a computer memory, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), an electric carrier signal, a telecommunication signal, and a software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0142] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0143] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0144] In the embodiments provided in the present application, it should be understood that the disclosed apparatus / computer equipment and methods can be implemented in other ways. For example, the apparatus / computer equipment embodiments described above are merely schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of the apparatus or unit, which can be electrical, mechanical or other forms.

[0145] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0146] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A phasor correction method, characterized in that: include: For three consecutive sampling points of the AC voltage, the real and imaginary functions of the three sampling points are combined to obtain the real value U of the three sampling points related to the system frequency. R(k-1) , U Rk , U R(k+1) The first expression of, and the imaginary value U of the system frequency and the three sampling points I(k-1) , U Ik , U I(k+1) The second expression of , integrating the first expression and the second expression according to the similar proportion principle, to obtain a calculation formula for the system frequency; The current system frequency is calculated using the real and imaginary values ​​of the three sampling points and the calculation formula of the system frequency; Based on the average value of the frequency over a period of time f avg The real part correction coefficient and the imaginary part correction coefficient are calculated with reference frequency f0, and the real part function and the imaginary part function of the sampling point are corrected according to the real part correction coefficient and the imaginary part correction coefficient.

2. The method according to claim 1, characterized in that The first expression includes the real value U of the three sampling points R(k-1) , U Rk , U R(k+1) and The second expression includes the imaginary values ​​U of the three sampling points I(k-1) , U Ik , U I(k+1) and Among them, T0 is the sampling period and N is the total number of sampling points.

3. The method according to claim 2, characterized in that The first expression is: The second expression is:

4. The method according to claim 3, characterized in that The system frequency is calculated as follows:

5. The method according to claim 3, characterized in that: The system frequency is calculated as follows: Where n is the size of the calculation window, and the upper limit of n is N / 8.

6. The method according to claim 2, characterized in that The real part correction coefficient is: The imaginary part correction coefficient is: in, 7. The method according to claim 6, characterized in that The real part function with the correction coefficient is: The imaginary function with correction coefficient is: Where Δf is the frequency deviation.

8. A phasor correction device, characterized in that: include: The frequency calculation module is used to combine the real and imaginary functions of the three consecutive sampling points of the AC voltage to obtain the real value U of the system frequency and the three sampling points. R(k-1) , U Rk , U R(k+1) The first expression of, and the imaginary value U of the system frequency and the three sampling points I(k-1) , U Ik , U I(k+1) The second expression of , integrating the first expression and the second expression according to the similar proportion principle, to obtain a calculation formula for the system frequency; The current system frequency is calculated using the real and imaginary values ​​of the three sampling points and the calculation formula of the system frequency; Phase correction module, used to calculate the average value of the frequency f over a period of time avg The real part correction coefficient and the imaginary part correction coefficient are calculated with reference frequency f0, and the real part function and the imaginary part function of the sampling point are corrected according to the real part correction coefficient and the imaginary part correction coefficient.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 7 is implemented.

10. A computer program product, characterized in that When the computer program product is executed on a computer device, the computer device is caused to execute the method according to any one of claims 1 to 7.

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