Photovoltaic inverter electric energy quality comprehensive control method and system

Abstract

The invention discloses a photovoltaic inverter electric energy quality comprehensive control method and system, and the method comprises the steps: obtaining an inverter access point voltage amplitude value, calculating a three-phase voltage mean value and the deviation of each phase voltage, and obtaining an inverter three-phase output active power value; performing three-phase imbalance compensation according to the active power value, and judging whether the three-phase voltage is balanced or not; if the balance is reached, the deviation between the line voltage value after the three-phase imbalance compensation and the upper and lower limit voltage values of the power grid is calculated, the three-phase output reactive power value of the inverter is obtained, and the line voltage is adjusted according to the reactive power value; the method comprises the following steps: adjusting a line voltage, obtaining an inverter access point line load current, calculating a three-phase harmonic current compensation value, carrying out line harmonic current compensation according to the three-phase harmonic current compensation value, and realizing inverter power quality comprehensive control and high-quality power supply based on the adjusted line voltage and the compensated line harmonic current.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic inverter control, and in particular to a photovoltaic inverter power quality comprehensive control method and system. Background Art

[0002] With the access of large-scale distributed photovoltaic power generation, the power quality problem of low-voltage distribution network has become increasingly prominent: the disorderly access and load imbalance characteristics of distributed photovoltaic power generation have aggravated the three-phase imbalance of the line; when photovoltaic power generation is large during the day, the load is low, and the voltage at the end of the line exceeds the upper limit, which may even cause damage to electrical equipment in severe cases; when there is no photovoltaic power generation at night, the power load is high, and the voltage at the end of the line exceeds the lower limit; multiple photovoltaic inverters are connected to the grid, causing the harmonic content of the grid to exceed the standard, causing grid voltage distortion, and even broadband oscillation problems in severe cases.

[0003] At present, smart capacitors, SVG, UPQC, APF and other power quality control equipment are usually added to the substation side. These devices only have single reactive power, voltage regulation and harmonic control functions and cannot achieve comprehensive control of power quality. Not only does it increase equipment investment, but it also increases line losses, which is not conducive to project implementation and promotion. Summary of the invention

[0004] In view of the above existing problems, the present invention is proposed.

[0005] Therefore, the present invention provides a photovoltaic inverter power quality comprehensive control method and system to solve the problem that the current power quality control equipment only has a single reactive power, voltage regulation, and harmonic control function and cannot achieve comprehensive control of power quality.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a photovoltaic inverter power quality comprehensive control method, comprising:

[0008] Obtain the voltage amplitude at the inverter access point, calculate the three-phase voltage mean and the deviation of each phase voltage, and obtain the three-phase output active power value of the inverter;

[0009] According to the active power value, three-phase unbalance compensation is performed, and whether the three-phase voltage is balanced is determined;

[0010] If balance is achieved, the deviation between the line voltage value after three-phase imbalance compensation and the upper and lower limit voltage values ​​of the power grid is calculated to obtain the three-phase output reactive power value of the inverter, and the line voltage is adjusted according to the reactive power value;

[0011] The line load current at the inverter access point is obtained, a three-phase harmonic current compensation value is calculated, and line harmonic current compensation is performed according to the three-phase harmonic current compensation value.

[0012] As a preferred solution of the photovoltaic inverter power quality comprehensive control method described in the present invention, the three-phase output active power value of the inverter includes:

[0013] The voltage deviation of the three phases is the average value of the three phase voltages, and the difference between the average value and the corresponding phase voltage;

[0014] The three-phase active power value is the product of the voltage deviation of the corresponding phase and the transfer function of the active power controller.

[0015] As a preferred solution of the photovoltaic inverter power quality comprehensive control method of the present invention, judging whether the three-phase voltage is balanced includes:

[0016] It is determined whether the average value of the three-phase voltage amplitude and the deviation of each phase voltage amplitude are both less than the set voltage threshold. If they are all less than the set point voltage threshold, the three-phase voltage balance is achieved.

[0017] As a preferred solution of the photovoltaic inverter power quality comprehensive control method described in the present invention, the calculation of the deviation between the line voltage value after three-phase unbalance compensation and the upper and lower limit voltage values ​​of the power grid includes:

[0018] When the average value of the three-phase voltage is greater than the upper limit voltage value of the power grid, the deviation is the difference between the average value of the three-phase voltage and the upper limit voltage of the power grid;

[0019] When the average value of the three-phase voltage is less than the lower limit voltage value of the power grid, the deviation is the difference between the average value of the three-phase voltage and the lower limit voltage of the power grid.

[0020] As a preferred solution of the photovoltaic inverter power quality comprehensive control method described in the present invention, the inverter three-phase output reactive power value includes:

[0021] The product of the reactive power controller transfer function, the line voltage amplitude after three-phase unbalance compensation and the deviation between the upper and lower limit voltage amplitudes of the power grid.

[0022] As a preferred solution of the photovoltaic inverter power quality comprehensive control method described in the present invention, the calculation of the three-phase harmonic current compensation value includes:

[0023] The fundamental active current of the three-phase load is the product of the fundamental active conductance and the per-unit value of the corresponding inverter access point voltage;

[0024] The fundamental reactive current of the three-phase load is the product of the fundamental reactive conductance and the per-unit value setting degree of the corresponding leading inverter access point voltage;

[0025] The three-phase harmonic current compensation value is the corresponding line load current minus the three-phase load fundamental active current minus the three-phase load fundamental reactive current.

[0026] In a second aspect, the present invention provides a photovoltaic inverter power quality integrated control system, comprising:

[0027] The first calculation module is used to obtain the voltage amplitude at the inverter access point, calculate the three-phase voltage mean and the deviation of each phase voltage, and obtain the three-phase output active power value of the inverter;

[0028] A judgment module, used to perform three-phase imbalance compensation according to the active power value and judge whether the three-phase voltage is balanced;

[0029] The second calculation module is used to calculate the deviation between the line voltage value after three-phase imbalance compensation and the upper and lower limit voltage values ​​of the power grid if balance is achieved, obtain the three-phase output reactive power value of the inverter, and adjust the line voltage according to the reactive power value;

[0030] The third calculation module is used to obtain the line load current of the inverter access point, calculate the three-phase harmonic current compensation value, and perform line harmonic current compensation according to the three-phase harmonic current compensation value.

[0031] As a preferred solution of the system of the photovoltaic inverter power quality comprehensive control method described in the present invention, it includes: overload operation at a set threshold multiple time.

[0032] In a third aspect, the present invention provides a computing device, comprising:

[0033] Memory and processor;

[0034] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the photovoltaic inverter power quality comprehensive control method are implemented.

[0035] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the photovoltaic inverter power quality comprehensive control method.

[0036] Compared with the prior art, the present invention has the following beneficial effects: the present invention performs comprehensive power quality control based on the redundant capacity of the photovoltaic inverter, reduces equipment investment, reduces line loss, and is easy to promote and apply. By adjusting the output of the photovoltaic inverter in real time, the present invention helps to balance the grid load, reduce voltage fluctuations, and thus enhance the overall stability of the grid, solve problems such as three-phase imbalance, reactive power overcompensation, high and low voltage, and excessive harmonics, significantly improves the power supply quality, reduces harmonic distortion in the grid, improves the reliability of electric energy, improves the power quality of the photovoltaic power generation system, and helps to promote a wider integration of renewable energy into the grid and support sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0038] Figure 1 A schematic diagram of the overall process logic of a photovoltaic inverter power quality comprehensive control method according to an embodiment of the present invention;

[0039] Figure 2 A system structure diagram of a photovoltaic inverter power quality comprehensive control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0041] Example 1

[0042] Reference Figure 1 , as an embodiment of the present invention, provides a photovoltaic inverter power quality comprehensive control method, comprising:

[0043] S100: Obtain the voltage amplitude of the inverter access point, calculate the three-phase voltage mean and the deviation of each phase voltage, and obtain the three-phase output active power value of the inverter;

[0044] S200: Perform three-phase unbalance compensation according to the active power value, and determine whether the three-phase voltage is balanced;

[0045] S300: If balance is achieved, the deviation between the line voltage value after three-phase imbalance compensation and the upper and lower limit voltage values ​​of the power grid is calculated to obtain the three-phase output reactive power value of the inverter, and the line voltage is adjusted according to the reactive power value;

[0046] S400: Based on the voltage amplitude of the inverter access point, obtain the line load current of the inverter access point, calculate the three-phase harmonic current compensation value, and perform line harmonic current compensation according to the three-phase harmonic current compensation value.

[0047] It should be noted that through the control technology of photovoltaic inverters, effective compensation and regulation of line three-phase imbalance, voltage fluctuations and harmonic currents are achieved, thereby improving the power quality. The redundant capacity of the photovoltaic inverter itself is used to carry out comprehensive control of power quality, reducing the investment in additional power quality control equipment. Since no additional power quality control equipment is required, the equipment investment is reduced, line losses are reduced, and energy utilization efficiency is improved.

[0048] In the embodiment of the present application, the above step S100 includes the following sub-steps A1-A2;

[0049] In A1: the voltage deviation of the three phases is the average value of the three phase voltages, and the difference between the average value and the corresponding phase voltage;

[0050] In A2: The active power value of the three phases is the product of the voltage deviation of the corresponding phase and the transfer function of the active power controller.

[0051] Specifically, the three-phase voltage at the access point of the photovoltaic inverter is detected, and the deviation between the mean value of the three-phase voltage and each voltage is calculated, which is expressed as:

[0052]

[0053] Then the three-phase output active power value of the photovoltaic inverter is expressed as:

[0054]

[0055] G PIp The transfer function for the active PI controller is expressed as:

[0056]

[0057] Among them, V a 、V b 、V c is the three-phase voltage amplitude of the photovoltaic inverter access point A, B, and C, G PIp is the active PI controller transfer function, ΔV ap , ΔV bp , ΔV cp are the deviations of the average voltage amplitudes of the three phases A, B, and C and the voltage amplitudes of each phase, k pp is the proportional adjustment coefficient, k Ip is the integral adjustment coefficient.

[0058] It should be noted that by calculating the average value of the three-phase voltage and comparing it with the voltage of each phase, the deviation of each phase from the average value can be obtained, which can accurately reflect the difference between the voltage of each phase and the overall voltage level. By using the calculated voltage deviation, the active power output of each phase is adjusted through the active PI controller transfer function to effectively compensate for the imbalance of the three-phase voltage, ensure that the three-phase voltage in the power grid is more balanced, and improve the power quality. By dynamically adjusting the active power output of the photovoltaic inverter, the voltage fluctuation in the power grid can be reduced, thereby improving the stability and reliability of the power grid.

[0059] In the embodiment of the present application, the above step S200 includes the following sub-step B1:

[0060] In B1: determine whether the average value of the three-phase voltage amplitude and the deviation of each phase voltage amplitude are both less than the set voltage threshold. If they are both less than the set point voltage threshold, the three-phase voltage balance is achieved.

[0061] Specifically, if the sampling accuracy is 1%, the voltage threshold is set to 2.2V, that is, when ΔV ap , ΔV bp , ΔV cp When all are less than 2.2V, the three-phase voltage is balanced.

[0062] It should be noted that by setting specific voltage thresholds, it is possible to accurately detect whether the three-phase voltage has reached a balanced state, which helps to promptly identify and adjust the unbalanced condition. When the three-phase voltage is close to balanced, measures can be taken to maintain this state and prevent grid problems caused by imbalance. By ensuring the balance of the three-phase voltage, voltage fluctuations and imbalances can be reduced, thereby improving the quality of power. Voltage imbalance will aggravate the generation of harmonics. By maintaining voltage balance, the generation of harmonics can be reduced and the quality of power can be further improved.

[0063] In the embodiment of the present application, the above step S300 includes the following sub-steps C1-C2;

[0064] In C1: When the average value of the three-phase voltage is greater than the upper limit voltage value of the power grid, the deviation is the difference between the average value of the three-phase voltage and the upper limit voltage of the power grid;

[0065] In C2: When the average value of the three-phase voltage is less than the lower limit voltage value of the power grid, the deviation is the difference between the average value of the three-phase voltage and the lower limit voltage of the power grid;

[0066] Specifically, the deviation between the line voltage value after three-phase unbalance compensation and the upper and lower limit voltage values ​​allowed by the power grid is expressed as:

[0067]

[0068] Among them, u limmaxis the upper limit voltage amplitude allowed by voltage, u limmin It is the lower voltage amplitude allowed by the power grid.

[0069] In the embodiment of the present application, after completing steps C1-C2 in the above step S300, the following sub-step C3 is also included;

[0070] In C3: the product of the reactive power controller transfer function and the deviation between the line voltage amplitude after three-phase unbalance compensation and the upper and lower limit voltage amplitudes of the power grid;

[0071] Specifically, the three-phase output reactive power value of the photovoltaic inverter is expressed as:

[0072]

[0073] Among them, G PIq is the reactive PI controller transfer function, ΔV q It is the deviation between the line voltage amplitude after three-phase unbalance compensation and the upper and lower limit voltage amplitudes allowed by the power grid.

[0074] It should be noted that by calculating the deviation between the average value of the three-phase voltage and the upper and lower voltage values ​​allowed by the power grid, the direction and amplitude of the voltage regulation can be accurately determined. According to the deviation value, the photovoltaic inverter can adjust its reactive power output to maintain the voltage within the range allowed by the power grid, thereby improving the stability and reliability of the power grid. Timely adjustment of reactive power output can prevent the voltage from exceeding the upper or lower limit allowed by the power grid and avoid damage to electrical equipment. Dynamic adjustment of reactive power output can improve the safety of power grid operation and reduce power grid failures caused by voltage instability. The application of the reactive PI controller transfer function allows more precise control of the distribution of reactive power to meet the voltage regulation needs of the power grid.

[0075] In the embodiment of the present application, the above step S400 includes the following sub-steps D1-D3;

[0076] In D1: the fundamental active current of the three-phase load is the product of the fundamental active conductance and the per-unit value of the corresponding inverter access point voltage;

[0077] In D2: the fundamental reactive current of the three-phase load is the product of the fundamental reactive conductance and the per-unit value setting degree of the corresponding leading inverter access point voltage;

[0078] In D3: the three-phase harmonic current compensation value is the corresponding line load current minus the three-phase load fundamental active current minus the three-phase load fundamental reactive current.

[0079] Specifically, set the degree to 90 degrees;

[0080] The fundamental active current of three-phase load is expressed as:

[0081]

[0082] The fundamental reactive current of three-phase load is expressed as:

[0083]

[0084] The three-phase harmonic current compensation value is expressed as:

[0085]

[0086] The fundamental active conductance and fundamental reactive conductance are expressed as:

[0087]

[0088] G LPF For a low-pass filter, the transfer function is expressed as:

[0089]

[0090] Among them, e as 、e bs 、e cs is the voltage at the access point of the photovoltaic inverter V a 、V b 、V c The per unit value, e ac 、e bc 、e cc Respectively ahead of e as 、e bs 、e cs 90 degrees, is the fundamental wave active conductance, is the fundamental wave reactive conductance, i La 、i Lb 、i Lc is the line load current.

[0091] It should be noted that the fundamental active and reactive currents of the three-phase load can be accurately calculated by multiplying the fundamental active and reactive conductance with the per-unit value of the corresponding voltage, which helps to more accurately analyze and control the current components in the power grid. By subtracting the fundamental active and reactive currents from the line load current, the harmonic current components can be identified, and the compensation current can be output in a targeted manner to reduce the harmonic content in the power grid. Compensating for the harmonic current can reduce the voltage distortion in the power grid, improve the power quality, and thus reduce the negative impact on the power grid and other electrical equipment. Based on the adjusted line voltage and compensated line harmonic current, the comprehensive control of the inverter power quality can be achieved.

[0092] The above is a schematic scheme of a photovoltaic inverter power quality comprehensive control method of this embodiment. It should be noted that the technical scheme of the photovoltaic inverter power quality comprehensive control system and the technical scheme of the photovoltaic inverter power quality comprehensive control method described above belong to the same concept, and the details of the technical scheme of the photovoltaic inverter power quality comprehensive control system not described in detail in this embodiment can be referred to the description of the technical scheme of the photovoltaic inverter power quality comprehensive control method described above.

[0093] The photovoltaic inverter power quality integrated control system in this embodiment includes:

[0094] The first calculation module is used to obtain the voltage amplitude at the inverter access point, calculate the three-phase voltage mean and the deviation of each phase voltage, and obtain the three-phase output active power value of the inverter;

[0095] A judgment module, used to perform three-phase imbalance compensation according to the active power value and judge whether the three-phase voltage is balanced;

[0096] The second calculation module is used to calculate the deviation between the line voltage value after three-phase imbalance compensation and the upper and lower limit voltage values ​​of the power grid if balance is achieved, obtain the three-phase output reactive power value of the inverter, and adjust the line voltage according to the reactive power value;

[0097] The third calculation module is used to obtain the line load current of the inverter access point, calculate the three-phase harmonic current compensation value, and perform line harmonic current compensation according to the three-phase harmonic current compensation value.

[0098] In the embodiment of the present application, the threshold is set to 1.2, that is, the system can operate at 1.2 times overload for a long time;

[0099] For example, the distribution transformer capacity of rural pole-mounted areas generally does not exceed 250kVA. Taking the most commonly used 70 square wire diameter as an example, the power supply radius is 500 meters, and the wire resistance and reactance are approximately 0.2 ohms. In order to ensure that the distribution transformer is not overloaded, the photovoltaic access capacity should be less than 0.8 times the distribution transformer capacity, that is, 200kVA. When the photovoltaic power is fully generated, the maximum active current is 303A, and the voltage at the end photovoltaic access point is 280.6V. In order for the voltage to meet the standard and not exceed +10%, that is, 242V, it is necessary to inject 193A reactive current. Therefore, in order to achieve power quality control, the photovoltaic inverter needs to have a total current output capacity of 359A, that is, 1.18 times the overload capacity.

[0100] like Figure 2 As shown, it includes a DC capacitor unit, a boost unit, an inverter unit, an AC filter unit, an AC voltage sampling unit, and a line current sampling unit. A photovoltaic inverter is installed on the low-voltage line. The photovoltaic inverter has a long-term overload capacity of 1.2 times, and an external current transformer is used to collect the line load current.

[0101] It should be noted that it has a higher safety margin, so the system is less likely to fail when facing grid fluctuations or increased loads. During peak grid demand or special circumstances, the system can withstand higher loads, which provides greater flexibility for the stable operation of the grid. In the case of large fluctuations in grid demand, it can make fuller use of the power generation capacity of the photovoltaic inverter and improve energy utilization while ensuring safety.

[0102] This embodiment also provides a computing device, which is applicable to the comprehensive control of power quality of photovoltaic inverters, including:

[0103] Memory and processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the comprehensive control method of photovoltaic inverter power quality proposed in the above embodiment.

[0104] This embodiment further provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for realizing the comprehensive control of power quality of a photovoltaic inverter as proposed in the above embodiment is implemented.

[0105] The storage medium proposed in this embodiment and the method for realizing comprehensive control of power quality of photovoltaic inverter proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0106] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (Random Access Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0107] Example 2

[0108] Referring to Table 1, this embodiment is different from the first embodiment in that it provides a verification test of a photovoltaic inverter power quality comprehensive control method to verify and illustrate the technical effects adopted in this method.

[0109] At noon, the actual measured line voltage is 254.49V for phase A, 248.44V for phase B, and 247.81V for phase C. The three phases are unbalanced, and the voltage exceeds the upper limit (242V).

[0110] The present application is applied to perform comprehensive adjustment based on redundant capacity, and the results are shown in Table 1;

[0111] Table 1 Line three-phase voltage before and after compensation

[0112]

[0113]

[0114] As shown in Table 1, the three-phase voltages after compensation are 238.35V for phase A, 238.63V for phase B, and 238.11V for phase C. After adjustment, the three-phase voltages are balanced and lower than the upper limit voltage of 242V.

[0115] Before compensation, there was an obvious imbalance in the three-phase voltage, with phase A being the highest and phase C being the lowest, and all three-phase voltages exceeding the upper voltage limit allowed by the power grid. After compensation, the three-phase voltages dropped significantly, and the differences between them became very small, almost reaching a balanced state, and also lower than the upper voltage limit.

[0116] After compensation, the difference between the three-phase voltages is significantly reduced, and the three-phase voltages are all reduced to the range allowed by the power grid. Through voltage balance and regulation, it helps to improve the stability of the power grid and reduce power grid failures caused by unbalanced or excessive voltage. Through comprehensive control, the power quality is improved, providing the power grid with more stable and more secure power.

[0117] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A photovoltaic inverter power quality comprehensive control method, characterized in that: include: Obtain the voltage amplitude at the inverter access point, calculate the three-phase voltage mean and the deviation of each phase voltage, and obtain the three-phase output active power value of the inverter; According to the active power value, three-phase unbalance compensation is performed, and whether the three-phase voltage is balanced is determined; If balance is achieved, the deviation between the line voltage value after three-phase imbalance compensation and the upper and lower limit voltage values ​​of the power grid is calculated to obtain the three-phase output reactive power value of the inverter, and the line voltage is adjusted according to the reactive power value; The line load current at the inverter access point is obtained, a three-phase harmonic current compensation value is calculated, and line harmonic current compensation is performed according to the three-phase harmonic current compensation value.

2. The photovoltaic inverter power quality comprehensive control method according to claim 1, characterized in that: The inverter three-phase output active power value includes: The voltage deviation of the three phases is the average value of the three phase voltages, and the difference between the average value and the corresponding phase voltage; The three-phase active power value is the product of the voltage deviation of the corresponding phase and the transfer function of the active power controller.

3. The photovoltaic inverter power quality comprehensive control method according to claim 1, characterized in that: Judging whether the three-phase voltage is balanced includes: It is determined whether the average value of the three-phase voltage amplitude and the deviation of each phase voltage amplitude are both less than the set voltage threshold. If they are all less than the set point voltage threshold, the three-phase voltage balance is achieved.

4. The photovoltaic inverter power quality comprehensive control method according to claim 1, characterized in that: The deviation between the line voltage value after calculating the three-phase unbalance compensation and the upper and lower limit voltage values ​​of the power grid includes: When the average value of the three-phase voltage is greater than the upper limit voltage value of the power grid, the deviation is the difference between the average value of the three-phase voltage and the upper limit voltage of the power grid; When the average value of the three-phase voltage is less than the lower limit voltage value of the power grid, the deviation is the difference between the average value of the three-phase voltage and the lower limit voltage of the power grid.

5. The photovoltaic inverter power quality comprehensive control method according to claim 1, characterized in that: The three-phase output reactive power value of the inverter includes: The product of the reactive power controller transfer function, the line voltage amplitude after three-phase unbalance compensation and the deviation between the upper and lower limit voltage amplitudes of the power grid.

6. The photovoltaic inverter power quality comprehensive control method according to claim 1, characterized in that: Calculation of three-phase harmonic current compensation value includes: The fundamental active current of the three-phase load is the product of the fundamental active conductance and the per-unit value of the corresponding inverter access point voltage; The fundamental reactive current of the three-phase load is the product of the fundamental reactive conductance and the per-unit value setting degree of the corresponding leading inverter access point voltage; The three-phase harmonic current compensation value is the corresponding line load current minus the three-phase load fundamental active current minus the three-phase load fundamental reactive current.

7. A system using the photovoltaic inverter power quality comprehensive control method according to any one of claims 1 to 6, characterized in that: include: The first calculation module is used to obtain the voltage amplitude at the inverter access point, calculate the three-phase voltage mean and the deviation of each phase voltage, and obtain the three-phase output active power value of the inverter; A judgment module, used to perform three-phase imbalance compensation according to the active power value and judge whether the three-phase voltage is balanced; The second calculation module is used to calculate the deviation between the line voltage value after three-phase imbalance compensation and the upper and lower limit voltage values ​​of the power grid if balance is achieved, obtain the three-phase output reactive power value of the inverter, and adjust the line voltage according to the reactive power value; The third calculation module is used to obtain the line load current of the inverter access point, calculate the three-phase harmonic current compensation value, and perform line harmonic current compensation according to the three-phase harmonic current compensation value.

8. The system of the photovoltaic inverter power quality comprehensive control method according to claim 7, characterized in that: include: Overload operation at a time multiple of the set threshold.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the photovoltaic inverter power quality comprehensive control method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the photovoltaic inverter power quality comprehensive control method according to any one of claims 1 to 7.

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