Voltage filtering methods, current filtering methods, equipment and media for distributed power sources

Abstract

This invention discloses a voltage filtering method, a current filtering method, an apparatus, and a medium. In voltage filtering, 2 hours of full-wave voltage values ​​are obtained through equal-time sampling; a preset fundamental component to be solved is acquired; these 2 hours of full-wave voltage values ​​are converted into a form based on the fundamental component and a coefficient matrix; then, filtering parameters corresponding to the fundamental voltage value in the fundamental component are calculated based on the inverse of the coefficient matrix and the 2 hours of full-wave voltage values; finally, the sampled full-wave voltage values ​​are filtered based on the filtering parameters. The same principle applies to current filtering. Therefore, this invention can accurately calculate a filtering scheme covering all harmonics using only the full-wave sampled values.

Description

Technical Field

[0001] This invention relates to the field of power system operation and analysis technology, and in particular to a voltage filtering method, current filtering method, device and medium for distributed power sources. Background Technology

[0002] New energy sources, represented by photovoltaics and wind power, have been largely connected to the power grid, with distributed new energy sources mainly connected to the distribution network. Distributed new energy sources are strategically deployed for energy transmission and utilization, effectively improving the security and flexibility of energy use.

[0003] However, the use of a large number of power electronic devices increases the harmonics in the output of distributed power sources, which increases the power loss of transmission lines. Although filters can be used to filter them, existing filters such as high-pass single-tuned filters are difficult to accurately compensate for the actual harmonics, resulting in poor actual filtering effect. Summary of the Invention

[0004] Therefore, it is necessary to provide voltage filtering methods, current filtering methods, equipment, and media for distributed power sources to solve the problem of difficulty in accurately compensating for actual harmonics, which leads to poor actual filtering effects.

[0005] A voltage filtering method for distributed power sources, the method comprising:

[0006] Two full-wave voltage values ​​were obtained by sampling at equal time intervals over a period of 2 hours. Each full-wave voltage value consists of the fundamental voltage value and the harmonic voltage values ​​from the 2nd to the hth order.

[0007] Obtain the preset basic components to be solved; wherein, the basic components include the fundamental voltage value and the harmonic voltage values ​​from the 2nd to the hth order at the initial sampling time;

[0008] The 2h full-wave voltage values ​​are converted into a form based on the basic components and coefficient matrix;

[0009] The filter parameters corresponding to the fundamental voltage values ​​in the basic components are calculated based on the inverse of the coefficient matrix and the 2h full-wave voltage values.

[0010] The sampled full-wave voltage value is filtered based on the filtering parameters.

[0011] In one embodiment, the first full-wave voltage value obtained from the sampling is:

[0012] U(t)=U1sin(ω0t)+U2sin(2ω0t)+..U h sin(hω0t)

[0013] In the above formula, U1 is the fundamental voltage value, U2 is the second harmonic voltage value, and U...h ω0 is the h-th harmonic voltage value; ω0 is the fundamental frequency; t is the initial sampling time.

[0014] The full-wave voltage value obtained from the sampling for the 2nd hour is:

[0015] U(t+(2h-1)T)=U1sin(ω0t+ω0(2h-1)T)+U2sin(2ω0t+2ω0(2h-1)T)+..U h sin(hω0t+hω0(2h-1)T)

[0016] In the above formula, T represents the time interval.

[0017] In one embodiment, the preset basic components to be solved include:

[0018] v1=U1sin(ω0t), v 11 =U1cos(ω0t),v2=U2sin(2ω0t),v 21 =U2cos(2ω0t)……

[0019] v h =U h sin(hω0t), v h1 =U h cos(hω0t).

[0020] In one embodiment, the relationship between the 2h full-wave voltage values ​​and the fundamental components and coefficient matrix is ​​as follows:

[0021]

[0022]

[0023] In the above formula, A is the coefficient matrix.

[0024] In one embodiment, the fundamental voltage value in the basic component is represented by the corresponding filtering parameters as follows:

[0025] v1=k0[k1U(t)+k2U(t+T)+...k 2h U(t+(2h-1)T)]

[0026] In the above formula, k0, k1, k2, ... k 2h These are the filter parameters.

[0027] A current filtering method for distributed power sources, the method comprising:

[0028] Two full-wave current values ​​were obtained by sampling at equal time intervals over a period of 2 hours. Each full-wave current value consists of the fundamental current value and the harmonic current values ​​from the 2nd to the hth order.

[0029] Obtain the preset basic components to be solved; wherein, the basic components include the fundamental current value and the harmonic current values ​​from the 2nd to the hth order at the initial sampling time;

[0030] The 2h full-wave current values ​​are converted into a form based on the basic components and coefficient matrix;

[0031] The filter parameters corresponding to the fundamental current value in the basic component are calculated based on the inverse of the coefficient matrix and the 2h full-wave current values.

[0032] The sampled full-wave current value is filtered based on the filtering parameters.

[0033] In one embodiment, the first full-wave current value obtained from the sampling is:

[0034] I(t)=I1sin(ω0t)+I2sin(2ω0t)+..I h sin(hω0t)

[0035] In the above formula, I1 is the fundamental current value, I2 is the second harmonic current value, and I... h ωh is the h-th harmonic current value; ω0 is the fundamental frequency; t is the initial sampling time.

[0036] The sampled full-wave current value for the 2nd hour is obtained as follows:

[0037] I(t+(2h-1)T)=I1sin(ω0t+ω0(2h-1)T)+I2sin(2ω0t+2ω0(2h-1)T)+..I h sin(hω0t+hω0(2h-1)T)

[0038] In the above formula, T represents the time interval.

[0039] In one embodiment, the preset basic components to be solved include:

[0040] v1=I1sin(ω0t), v 11 =I1cos(ω0t),v2=I2sin(2ω0t),v 21 =I2cos(2ω0t)……

[0041] v h =I h sin(hω0t), v h1 =I h cos(hω0t).

[0042] A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the voltage filtering method and current filtering method of the distributed power source described above.

[0043] An output filtering device for a distributed power source includes a memory and a processor. The memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of the voltage filtering method and current filtering method for the distributed power source described above.

[0044] This invention provides a voltage filtering method, a current filtering method, equipment, and a medium for distributed power sources. In voltage filtering, 2 hours of full-wave voltage values ​​are obtained through equal-time sampling; a preset fundamental component to be solved is acquired; these 2 hours of full-wave voltage values ​​are converted into a form based on the fundamental component and a coefficient matrix; then, the filtering parameters corresponding to the fundamental voltage value in the fundamental component are calculated based on the inverse of the coefficient matrix and the 2 hours of full-wave voltage values; finally, the sampled full-wave voltage values ​​are filtered based on the filtering parameters. The same principle applies to current filtering. Therefore, this invention can accurately calculate a filtering scheme covering all harmonics using only the full-wave sampled values. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] in:

[0047] Figure 1 This is a flowchart illustrating a voltage filtering method for a distributed power source in one embodiment.

[0048] Figure 2 This is a schematic diagram of the waveform before filtering in one embodiment;

[0049] Figure 3 This is a schematic diagram of the filtered waveform in one embodiment;

[0050] Figure 4 This is a flowchart illustrating a current filtering method for a distributed power source in one embodiment.

[0051] Figure 5 This is a structural block diagram of the output filtering device of a distributed power source in one embodiment. Detailed Implementation

[0052] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0053] It is known that distributed generation systems typically employ a large number of power electronic devices, and their output contains significant harmonic components. Therefore, designing an effective filtering scheme for distributed generation systems is crucial. The solution proposed in this invention is as follows:

[0054] like Figure 1 As shown, Figure 1 This is a flowchart illustrating a voltage filtering method for a distributed power source in one embodiment. The steps provided by the voltage filtering method for a distributed power source in this embodiment include:

[0055] S101, acquire 2h full-wave voltage values ​​obtained by sampling at equal time intervals.

[0056] Each full-wave voltage value consists of the fundamental voltage value and the harmonic voltage values ​​from the 2nd to the hth order. Typically...

[0057] In other words, the full-wave voltage value is expressed as:

[0058] U(t)=U1sin(ω0t+θ1)+U2sin(2ω0t+θ2)+..U h sin(hω0t+θ h (1)

[0059]

[0060] In the above formula, U1 is the fundamental voltage value, U2 is the second harmonic voltage value, and U... h The value is the h-th harmonic voltage.

[0061] ω0 is the fundamental frequency, t is the initial sampling time, θ1 represents the initial phase angle of the fundamental frequency, θ2 represents the initial phase angle of the second harmonic, and θ... h f represents the initial phase angle of the h-th harmonic. norm This indicates the system's rated frequency, for example, set to 50Hz.

[0062] In one specific embodiment, to simplify subsequent analysis, the first full-wave electrical signal obtained from the sampling will be used.

[0063] Pressure value is expressed as:

[0064] U(t)=U1sin(ω0t)+U2sin(2ω0t)+..U hsin(hω0t) (3)

[0065] Furthermore, assuming the calculation time interval of the monitoring equipment is T, then the full-wave voltage value obtained at t+T is...

[0066] Represented as:

[0067] U(t+T)=U1sin(ω0t+ω0T)+U2sin(2ω0t+2ω0T)+..U h sin(hω0t+hω0T) (4)

[0068] Equation (4) can be expanded using trigonometric functions to obtain equation (5):

[0069] U(t+T)=U1sin(ω0t)cos(ω0T)+U1cos(ω0t)sin(ω0T)+U2sin(2ω0t)cos(2ω0T)+

[0070] U2cos(2ω0t)sin(2ω0T)+...+U h sin(hω0t)cos(hω0T)+U h cos(hω0t)sin(hω0T))(5)

[0071] In this embodiment, 2 hours of full-wave voltage values ​​need to be sampled at equal time intervals. Therefore, the last sampled full-wave voltage value is represented as:

[0072] U(t+(2h-1)T)=U1sin(ω0t+ω0(2h-1)T)+U2sin(2ω0t+2ω0(2h-1)T)+..U h sin(hω0t+hω0(2h-1)T)(6)

[0073] Similarly, equation (6) can also be expanded using trigonometric functions.

[0074] S102, Obtain the preset basic components to be solved.

[0075] The fundamental component includes the fundamental voltage value and the harmonic voltage values ​​from the 2nd to the hth order at the initial sampling time. U(t), U(t+T)...U(t+(2h-1)T) obtained by sampling in S101 can all be represented by this fundamental component.

[0076] In one specific embodiment, the basic components to be solved include:

[0077] v1=U1sin(ω0t), v 11 =U1cos(ω0t),v2=U2sin(2ω0t),v 21=U2cos(2ω0t)……v h =U h sin(hω0t), v h1 =U h cos(hω0t).

[0078] S103 converts the 2h full-wave voltage values ​​into a form based on the fundamental components and coefficient matrix.

[0079] That is, it can be expressed as:

[0080]

[0081]

[0082] In the above formula, A is the coefficient matrix.

[0083] S104, calculate the filtering parameters corresponding to the fundamental voltage value in the basic component based on the inverse of the coefficient matrix and 2h full-wave voltage values.

[0084] Since U(t), U(t+T)...U(t+(2h-1)T) can be obtained directly by sampling through monitoring equipment, and the parameters in the coefficient matrix A are either set by the user or known, the coefficient matrix A can be calculated directly. Therefore, by multiplying both sides of equation (7) by the inverse of A, v1 and v2 can be solved. 11 v2, v 21 …v h v h1 .

[0085] Where v1 can be expressed as shown in equation (9):

[0086] v1=k0[k1U(t)+k2U(t+T)+...k 2h U(t+(2h-1)T)] (9)

[0087] In the above formula, k0, k1, k2…k 2h These are the filter parameters.

[0088] S105 filters the sampled full-wave voltage value based on the filtering parameters.

[0089] Therefore, given only the full-wave data U(t), U(t+T)…U(t+(2h-1)T), a voltage filter composed of proportional sums can be accurately and dynamically designed.

[0090] The following example illustrates how, when only a certain harmonic is filtered out, equation (3) can be rewritten as:

[0091] U(t) = U1sin(ω0t) + U hsin(hω0t) (10)

[0092] Since it is necessary to obtain the fourth equation, the four full-wave voltage values ​​obtained by sampling at equal time intervals can be intuitively rewritten as follows:

[0093]

[0094] Equation (9) can then be further specified as shown in equation (12):

[0095] v1=k0[k1U(t)+k2U(t+T)+k3U(t+2T)+k4U(t+3T)] (12)

[0096] Combining equations (11) and (12) into equation (13), we get k1=-cos(ω0T), k2=2cos(ω0T)cos(hω0T)+0.5, k3=-cos(ω0T)-cos(hω0T), k4=0.5

[0097] Assuming that the 5th, 7th, 11th, and 13th harmonics in the power grid each contain 10%, their original waveforms are as follows: Figure 2 As shown, the horizontal axis represents time, and the vertical axis represents the voltage per unit value. Figure 2 The waveform distortion of the power grid is clearly visible.

[0098] Based on the formula derived above: k1 = -cos(ω0T), k2 = 2cos(ω0T)cos(hω0T) + 0.5, k3 = -cos(ω0T) -cos(hω0T), k4 = 0.5. Design filters with orders h = 5, 7, 11, and 13 respectively. The waveforms after using the filters are as follows: Figure 3 As shown, the power grid waveform is clearly smoothed, and the filtering effect is obvious. It is evident that this invention can accurately calculate a filtering scheme covering all harmonics using full-wave sampling values.

[0099] Similarly, this invention also proposes a current filtering method for distributed power sources, such as... Figure 4 As shown, Figure 4 This is a flowchart illustrating a current filtering method for a distributed power source in one embodiment. The steps provided by the current filtering method for a distributed power source in this embodiment include:

[0100] S401, acquire 2h full-wave current values ​​obtained by sampling at equal time intervals.

[0101] Each full-wave current value consists of the fundamental current value and the harmonic current values ​​from the 2nd to the hth order. Typically, this full-wave current value is expressed as:

[0102] I(t)=I1sin(ω0t+θ1)+I2sin(2ω0t+θ2)+..I h sin(hω0t+θ h (13)

[0103]

[0104] In the above formula, I1 is the fundamental current value, I2 is the second harmonic current value, and I... h Here, ω is the h-th harmonic current value; ω0 is the fundamental frequency; t is the initial sampling time; θ1 represents the initial phase angle of the fundamental wave; θ2 represents the initial phase angle of the second harmonic; and θ... h f represents the initial phase angle of the h-th harmonic. norm This indicates the system's rated frequency, for example, set to 50Hz.

[0105] In one specific embodiment, for the sake of simplifying the subsequent analysis, the first full-wave current value obtained from the sampling is represented as:

[0106] I(t)=I1sin(ω0t)+I2sin(2ω0t)+..I h sin(hω0t) (15)

[0107] Furthermore, assuming the calculation time interval of the monitoring equipment is T, the full-wave current value obtained at t+T is expressed as:

[0108] I(t+T)=I1sin(ω0t+ω0T)+I2sin(2ω0t+2ω0T)+..I h sin(hω0t+hω0T) (16)

[0109] Equation (16) can be expanded using trigonometric functions into equation (17), resulting in:

[0110]

[0111] In this embodiment, 2 hours of full-wave current values ​​need to be sampled at equal time intervals. Therefore, the last sampled full-wave current value is represented as:

[0112] I(t+(2h-1)T)=I1sin(ω0t+ω0(2h-1)T)+I2sin(2ω0t+2ω0(2h-1)T)+..I h sin(hω0t+hω0(2h-1)T) (18)

[0113] Similarly, equation (18) can also be expanded using trigonometric functions.

[0114] S402, Obtain the preset basic components to be solved.

[0115] The basic components include the fundamental current value at the initial sampling time and the harmonic current values ​​from the 2nd to the hth order.

[0116] The I(t), I(t+T)...I(t+(2h-1)T) obtained by sampling in S401 can all be represented by this basic component.

[0117] In one specific embodiment, the basic components to be solved include:

[0118] v1=I1sin(ω0t), v 11 =I1cos(ω0t),v2=I2sin(2ω0t),v 21 =I2cos(2ω0t)……v h =I h sin(hω0t), v h1 =I h cos(hω0t).

[0119] S403 converts the 2h full-wave current values ​​into a form based on the fundamental components and coefficient matrix.

[0120] That is, it can be expressed as:

[0121]

[0122]

[0123] In the above formula, A is the coefficient matrix.

[0124] S404, calculate the filtering parameters corresponding to the fundamental current value in the basic component based on the inverse of the coefficient matrix and 2h full-wave current values.

[0125] Since I(t), I(t+T)...I(t+(2h-1)T) can be obtained directly by sampling through monitoring equipment, and the parameters in the coefficient matrix A are either set by the user or known, the coefficient matrix A can be calculated directly. Therefore, by multiplying both sides of equation (19) by the inverse of A, v1 and v2 can be solved. 11 v2, v 21 …v h v h1 .

[0126] v1 can be expressed as shown in equation (21):

[0127] v1=k0[k1I(t)+k2I(t+T)+...k 2h I(t+(2h-1)T)] (21)

[0128] In the above formula, k0, k1, k2…k 2hThese are the filter parameters.

[0129] S405 filters the sampled full-wave current value based on the filtering parameters.

[0130] Therefore, given only the full-wave data I(t), I(t+T)…I(t+(2h-1)T), a current filter composed of proportional sums can be accurately and dynamically designed.

[0131] Figure 5 An internal structural diagram of the output filtering device of a distributed power source in one embodiment is shown. Figure 5 As shown, the output filtering device of the distributed power source includes a processor, a memory, and a network interface connected via a system bus. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium of the distributed power source's output filtering device stores an operating system and may also store a computer program. When executed by the processor, this computer program enables the processor to implement voltage filtering and current filtering methods for the distributed power source. The internal memory may also store a computer program, which, when executed by the processor, enables the processor to implement voltage filtering and current filtering methods for the distributed power source. Those skilled in the art will understand that... Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the solution of this application and does not constitute a limitation on the output filtering device of the distributed power supply to which the solution of this application is applied. The specific output filtering device of the distributed power supply may include more or fewer components than shown in the figure, or combine certain components, or have different component arrangements.

[0132] An output filtering device for a distributed power source includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it performs the following steps: acquiring 2h full-wave voltage values ​​sampled at equal time intervals; acquiring a preset fundamental component to be solved; converting the 2h full-wave voltage values ​​into a form based on the fundamental component and a coefficient matrix; calculating the filtering parameters corresponding to the fundamental voltage value in the fundamental component based on the inverse of the coefficient matrix and the 2h full-wave voltage values; and filtering the sampled full-wave voltage values ​​based on the filtering parameters.

[0133] The following steps are performed: obtaining 2h full-wave current values ​​sampled at equal time intervals; obtaining a preset basic component to be solved; converting the 2h full-wave current values ​​into a form based on the basic component and a coefficient matrix; calculating the filtering parameters corresponding to the fundamental current value in the basic component based on the inverse of the coefficient matrix and the 2h full-wave current values; and filtering the sampled full-wave current values ​​based on the filtering parameters.

[0134] A computer-readable storage medium storing a computer program, which, when executed by a processor, performs the following steps: acquiring 2h full-wave voltage values ​​sampled at equal time intervals; acquiring a preset fundamental component to be solved; converting the 2h full-wave voltage values ​​into a form based on the fundamental component and a coefficient matrix; calculating filtering parameters corresponding to the fundamental voltage value in the fundamental component based on the inverse of the coefficient matrix and the 2h full-wave voltage values; and filtering the sampled full-wave voltage values ​​based on the filtering parameters.

[0135] The following steps are performed: obtaining 2h full-wave current values ​​sampled at equal time intervals; obtaining a preset basic component to be solved; converting the 2h full-wave current values ​​into a form based on the basic component and a coefficient matrix; calculating the filtering parameters corresponding to the fundamental current value in the basic component based on the inverse of the coefficient matrix and the 2h full-wave current values; and filtering the sampled full-wave current values ​​based on the filtering parameters.

[0136] It should be noted that the voltage filtering method, current filtering method, device and medium of the above-mentioned distributed power source belong to a general inventive concept, and the contents of the embodiments of the voltage filtering method, current filtering method, device and medium of the distributed power source are applicable to each other.

[0137] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0138] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0139] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A voltage filtering method for distributed power sources, characterized in that, The method includes: Two full-wave voltage values ​​were obtained by sampling at equal time intervals over a period of 2 hours. Each full-wave voltage value consists of the fundamental voltage value and the harmonic voltage values ​​from the 2nd to the hth order. Obtain the preset basic components to be solved; wherein, the basic components include the fundamental voltage value and the harmonic voltage values ​​from the 2nd to the hth order at the initial sampling time; The 2h full-wave voltage values ​​are converted into a form based on the basic components and coefficient matrix; The filter parameters corresponding to the fundamental voltage value in the basic component are calculated based on the inverse of the coefficient matrix and the 2h full-wave voltage values. The sampled full-wave voltage value is filtered based on the aforementioned filtering parameters; The first full-wave voltage value obtained from the sampling is: In the above formula, This is the fundamental voltage value. This is the second harmonic voltage value. The value of the h-th harmonic voltage; Where t is the fundamental frequency and t is the initial sampling time; The full-wave voltage value obtained from the sampling for the 2nd hour is: In the above formula, T is the time interval; The basic components to be solved are: ， ， ， …… ， ； The relationship between the 2h full-wave voltage values ​​and the fundamental components and coefficient matrix is ​​as follows: In the above formula, A is the coefficient matrix.

2. The method according to claim 1, characterized in that, The fundamental voltage value in the basic component is represented by the corresponding filtering parameters as follows: In the above formula, These are the filter parameters.

3. A current filtering method for distributed power sources, characterized in that, The method includes: Two full-wave current values ​​were obtained by sampling at equal time intervals over a period of 2 hours. Each full-wave current value consists of the fundamental current value and the harmonic current values ​​from the 2nd to the hth order. Obtain the preset basic components to be solved; wherein, the basic components include the fundamental current value and the harmonic current values ​​from the 2nd to the hth order at the initial sampling time; The 2h full-wave current values ​​are converted into a form based on the basic components and coefficient matrix; The filter parameters corresponding to the fundamental current value in the basic component are calculated based on the inverse of the coefficient matrix and the 2h full-wave current values. The sampled full-wave current value is filtered based on the aforementioned filtering parameters; The first full-wave current value obtained from the sampling is: In the above formula, This is the fundamental current value. This is the value of the second harmonic current. The value of the h-th harmonic current; Where t is the fundamental frequency and t is the initial sampling time; The sampled full-wave current value for the 2nd hour is obtained as follows: In the above formula, T is the time interval; The basic components to be solved are: ， ， ， …… ， ； The relationship between the 2h full-wave current values ​​and the fundamental components and coefficient matrix is ​​as follows: In the above formula, A is the coefficient matrix.

4. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, the processor performs the steps of the method as described in any one of claims 1 to 3.

5. An output filtering device for a distributed power source, comprising a memory and a processor, characterized in that, The memory stores a computer program that, when executed by the processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 3.

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