Automatic regulation and control method, device and control system for high-proportion distributed photovoltaic inverter

Abstract

The invention provides an automatic regulation and control method, device and control system for a high-proportion distributed photovoltaic inverter, and is applied to the technical field of distributed photovoltaic power generation operation. The method is applied to automatic regulation and control devices of the distributed photovoltaic inverters, each automatic regulation and control device is in communication connection with one distributed photovoltaic inverter, and the method comprises the following steps: acquiring alternating current side frequency and alternating current side voltage of the distributed photovoltaic inverters; performing droop control of the active power of the distributed photovoltaic inverter based on the alternating current side frequency so as to cooperate with active power regulation and control of a power grid; and performing droop control of reactive power of the distributed photovoltaic inverter based on the alternating current side voltage so as to cooperate with reactive power regulation and control of a power grid. The problems that low-voltage grid-connected related equipment is difficult to effectively regulate and control in real time, and safe and stable operation of the power distribution network and use safety of electric equipment of a user are affected due to the fact that high-proportion distributed photovoltaic power generation is connected into the low-voltage power distribution network are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of distributed photovoltaic power generation operation, and in particular to an automatic control method, device and control system for a high-ratio distributed photovoltaic inverter. Background Art

[0002] Driven by the dual carbon goals, my country's distributed photovoltaics are accelerating their development, with installed capacity and penetration continuing to rise. The large-scale and intensive grid connection of distributed photovoltaics will lead to large-scale power reverse transmission and frequent voltage fluctuations in the distribution area, increasing the difficulty of distribution network operation control and management, and posing major challenges to the safe, stable and economic operation of the distribution network.

[0003] At present, my country's distributed photovoltaic power generation mainly adopts two modes: 10kV or 35kV medium voltage grid connection and 0.4kV low voltage grid connection. For the distributed photovoltaic power generation system connected to the 0.4kV low voltage grid, due to the small installed capacity and considering the investment cost, the real-time operation information of the relevant equipment is not connected to the dispatching and operation organization of the power grid company. Some information is often connected to the marketing department of the power grid company through smart meters and electricity information collection channels. The collection time interval is generally hourly or even longer, which makes it difficult to effectively dispatch and control. The access of a large number of distributed photovoltaic power generation to the low-voltage distribution network will significantly change the size and direction of the flow, causing the voltage distribution of each node on the distribution line to change significantly. When the photovoltaic power generation output is large, local power grid overvoltage occurs, or the distribution transformer is reversed and overloaded or even overloaded, which endangers the safe and stable operation of the distribution network and the safety of users' electrical equipment. Summary of the invention

[0004] In order to overcome the problem that the above-mentioned low-voltage grid-connected related equipment is difficult to effectively regulate in real time and the high-proportion distributed photovoltaic power generation connected to the low-voltage distribution network affects the safe and stable operation of the distribution network and the safety of users' electrical equipment, the present invention provides a high-proportion distributed photovoltaic inverter automatic regulation method, device and control system.

[0005] On the one hand, the present invention provides a high-ratio distributed photovoltaic inverter automatic control method, which is applied to the automatic control device of the distributed photovoltaic inverter, each of which is communicatively connected to one of the distributed photovoltaic inverters, and the method comprises:

[0006] Acquiring an AC side frequency and an AC side voltage of the distributed photovoltaic inverter;

[0007] Performing droop control on the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid;

[0008] Based on the AC side voltage, the reactive power of the distributed photovoltaic inverter is controlled to droop, so as to cooperate with the reactive power regulation of the power grid;

[0009] Wherein, the distributed photovoltaic inverter is used for low-voltage grid connection of a distributed photovoltaic power generation system.

[0010] Optionally, the droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid includes:

[0011] When the AC side frequency is in the frequency regulation response area, if the AC side frequency is less than the first frequency regulation boundary value, the distributed photovoltaic inverter active power is drooped based on the AC side frequency and the first droop control relationship to cooperate with the active power regulation of the power grid;

[0012] If the AC side frequency is greater than or equal to the first frequency modulation boundary value, the distributed photovoltaic inverter active power is drooped based on the AC side frequency and the second droop control relationship to cooperate with the active power regulation of the power grid;

[0013] The absolute value of the slope of the curve corresponding to the first droop control relationship is smaller than the absolute value of the slope of the curve corresponding to the second droop control relationship.

[0014] Optionally, the droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid includes:

[0015] When the AC side voltage is in the voltage regulation response area, performing droop control on the reactive power of the distributed photovoltaic inverter based on the AC side voltage and a third droop control relationship to cooperate with reactive power regulation of the power grid;

[0016] Among them, if the AC side voltage is higher than the maximum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the maximum voltage value of the voltage control dead zone and the first voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; if the AC side voltage is lower than the minimum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the minimum voltage value of the voltage control dead zone and the second voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; the difference between the first voltage limit and the second voltage limit is greater than the difference between the two endpoint values ​​of the voltage control dead zone.

[0017] Optionally, the droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid also includes:

[0018] If the distributed photovoltaic inverter absorbs reactive power of the power grid at the maximum reactive power regulation value and the AC side voltage is higher than the first voltage limit, the distributed photovoltaic inverter is controlled to absorb reactive power at the maximum reactive power regulation value, and the distributed photovoltaic inverter is controlled to droop the active power based on the AC side voltage and the fourth droop control relationship to cooperate with reactive power regulation of the power grid;

[0019] The fourth droop control relationship is determined based on the ratio of the difference between the first voltage limit and the preset maximum adjustable voltage to the maximum reactive power regulation value of the distributed photovoltaic inverter.

[0020] Optionally, the droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid also includes:

[0021] If the AC side frequency is greater than or equal to the second frequency regulation boundary value and less than or equal to the maximum limit of the frequency regulation response area, the active power of the distributed photovoltaic inverter is controlled based on the active power corresponding to the maximum active power reduction amount;

[0022] Among them, the second frequency modulation boundary value is greater than or equal to the first frequency modulation boundary value, and the maximum active power reduction amount is determined based on the rated power of the distributed photovoltaic inverter and the maximum reduction ratio configured by the user.

[0023] Optionally, the droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid also includes:

[0024] If the AC side voltage is lower than the second voltage limit, the distributed photovoltaic inverter is controlled to output reactive power to the power grid at a maximum reactive power regulation value.

[0025] Optionally, after acquiring the AC side frequency and the AC side voltage of the distributed photovoltaic inverter, the method further includes:

[0026] Determine whether the AC side frequency is in a frequency control dead zone, and if so, control the operation of the distributed photovoltaic inverter based on a maximum power tracking mode;

[0027] Determine whether the AC side voltage is in a voltage regulation dead zone, and if so, control the distributed photovoltaic inverter to operate based on a maximum power tracking mode and a power factor of 1.

[0028] Optionally, before acquiring the AC side frequency and the AC side voltage of the distributed photovoltaic inverter, the method further includes:

[0029] Receive active and / or reactive power control instructions sent by the regional terminal or remote monitoring subsystem;

[0030] The active and / or reactive power of the distributed photovoltaic inverter is controlled and adjusted based on the active and / or reactive control instructions.

[0031] Optionally, after acquiring the AC side frequency and the AC side voltage of the distributed photovoltaic inverter, the method further includes:

[0032] Determining whether to perform droop control of the active power of the distributed photovoltaic inverter based on the received active power regulation mode parameters configured by the user;

[0033] If it is determined that the distributed photovoltaic inverter active power droop control is not performed, controlling the operation of the distributed photovoltaic inverter based on a maximum power tracking mode;

[0034] Determining whether to perform droop control of reactive power of the distributed photovoltaic inverter based on the reactive power control mode parameters configured by the user received;

[0035] If it is determined not to perform droop control on the reactive power of the distributed photovoltaic inverter, the distributed photovoltaic inverter is controlled to operate based on a maximum power tracking mode and a power factor of 1.

[0036] Optionally, the droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency further includes:

[0037] If the output active power of the distributed photovoltaic inverter is less than the target value, exit the droop control process, and control the operation of the distributed photovoltaic inverter in the maximum power tracking mode;

[0038] The target value is a specified proportion of the rated power of the distributed photovoltaic inverter.

[0039] Optionally, after acquiring the AC side frequency and the AC side voltage of the distributed photovoltaic inverter, the method further includes:

[0040] If the AC side frequency exceeds the maximum limit of the frequency control response zone or the AC side voltage reaches a preset maximum adjustable voltage, the distributed photovoltaic inverter is controlled to stop generating electricity.

[0041] Optionally, before receiving the active power and / or reactive power control instruction sent by the regional terminal or the remote monitoring subsystem, the method further includes:

[0042] Acquiring real-time operating data of the distributed photovoltaic inverter;

[0043] Perform encryption processing on the real-time operation data based on a power grid-specific encryption method to obtain corresponding encrypted data;

[0044] The encrypted data is sent to the regional terminal or the remote monitoring subsystem, so that the regional terminal or the remote monitoring subsystem aggregates the received encrypted data of each distributed photovoltaic inverter and sends the aggregated result to the power grid management agency.

[0045] On the other hand, the present invention also provides a high-ratio distributed photovoltaic inverter automatic control device, each of the automatic control devices is communicatively connected to one of the distributed photovoltaic inverters, and each of the automatic control devices includes:

[0046] A communication module, used to obtain the AC side frequency and AC side voltage of the distributed photovoltaic inverter;

[0047] An active power control module, used to perform droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid;

[0048] A reactive power control module, used for performing droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid;

[0049] Wherein, the distributed photovoltaic inverter is used for low-voltage grid connection of a distributed photovoltaic power generation system.

[0050] On the other hand, the present invention further provides a control system for a high-ratio distributed photovoltaic inverter, comprising: an automatic control device for a high-ratio distributed photovoltaic inverter as described in any one of the above items.

[0051] On the other hand, the present invention also provides an electronic device, comprising: at least one processor and a memory; the memory and the processor are connected via a bus;

[0052] The memory is used to store one or more programs;

[0053] When the one or more programs are executed by the at least one processor, any one of the above-mentioned methods for automatic control of high-ratio distributed photovoltaic inverters is implemented.

[0054] On the other hand, the present invention further provides a readable storage medium having an execution program stored thereon, and when the execution program is executed, the automatic control method of a high-ratio distributed photovoltaic inverter described in any one of the above items is implemented.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] The present invention provides a high-proportion distributed photovoltaic inverter automatic control method and device, by acquiring the AC side frequency and AC side voltage of the distributed photovoltaic inverter, and based on this, performing droop control of the active power and reactive power of the inverter on the distributed photovoltaic inverter side to cooperate with the active and reactive power control of the power grid. On the one hand, in the case of high-proportion distributed photovoltaic power generation, each distributed photovoltaic inverter automatically cooperates with the active and reactive power control of the power grid, and realizes real-time and effective control of low-voltage grid-connected equipment without equipment modification; on the other hand, through real-time automatic control of the active and reactive power of each distributed photovoltaic inverter connected to the power grid, the occurrence of local power grid overvoltage and distribution overload operation caused by large photovoltaic power generation output is greatly reduced, and the safe and stable operation capability of the distribution network and the safety of power equipment are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 A schematic diagram of a process flow of a high-ratio distributed photovoltaic inverter automatic control method of the present invention;

[0058] Figure 2 A schematic diagram of the connection between an automatic control device and a photovoltaic inverter according to an example of the present invention;

[0059] Figure 3 A schematic diagram of an active power control process of an automatic control method for a high-ratio distributed photovoltaic inverter of the present invention;

[0060] Figure 4 A schematic diagram of a reactive power control process of an automatic control method for a high-ratio distributed photovoltaic inverter according to the present invention;

[0061] Figure 5 A schematic diagram of an active power-frequency droop control curve corresponding to an active power regulation process of the present invention;

[0062] Figure 6 A schematic diagram of a power-voltage droop control curve corresponding to a reactive power regulation process of the present invention;

[0063] Figure 7 This is one of the hardware topology diagrams of a high-ratio distributed photovoltaic inverter automatic control device of the present invention;

[0064] Figure 8 This is a second schematic diagram of the hardware topology structure of a high-ratio distributed photovoltaic inverter automatic control device of the present invention;

[0065] Fig. 9 A communication conversion schematic diagram of a high-ratio distributed photovoltaic inverter automatic control device of the present invention;

[0066] Fig.10A communication network diagram of a high-ratio distributed photovoltaic inverter automatic control device of the present invention;

[0067] Fig.11 It is a schematic structural diagram of the electronic device of the present invention. DETAILED DESCRIPTION

[0068] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0069] Example 1

[0070] The present invention provides a method for automatically controlling a high-proportion distributed photovoltaic inverter, as shown in the schematic diagram Figure 1 As shown, including:

[0071] Step S110, obtaining the AC side frequency and AC side voltage of the distributed photovoltaic inverter;

[0072] Step S120, performing droop control on the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid;

[0073] Step S130, performing droop control on the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid;

[0074] In this example implementation, the execution subject of this method is an automatic control device designed for each distributed photovoltaic inverter, and each of the automatic control devices is connected to a distributed photovoltaic inverter in communication, for example, each automatic control device is connected to a distributed photovoltaic inverter via a communication interface. Figure 2As shown, the automatic control device can be connected to the communication interface position of the photovoltaic inverter. If the automatic control device includes a power carrier communication HPLC communication interface, an AC coupling line can be drawn from the AC interface of the inverter as a carrier communication signal; the photovoltaic inverter comes with a communication stick that can be connected to other communication interfaces of the automatic control device. The automatic control device can be designed as a control rod or control box of a distributed photovoltaic inverter. The control rod can be connected to the RS485 serial port of the photovoltaic inverter through a plug-in connection, and the control box can be connected to the RS485 serial port of the photovoltaic inverter through an RS485 communication line. In this way, the automatic control device can directly read the AC side frequency and voltage of the photovoltaic inverter. The distributed photovoltaic inverter is used for low-voltage grid-connected distributed photovoltaic power generation systems. That is to say, the present invention is designed for the photovoltaic low-voltage grid-connected process. The present invention can control the active output of the inverter based on the AC side frequency, and control the reactive output of the inverter based on the AC side voltage, that is, the active and reactive power of the inverter can be automatically controlled according to the real-time AC side frequency and AC side voltage, so that the inverter can participate in the grid regulation and control, and the adaptive control of the photovoltaic inverter can be realized. The active control function can support distributed photovoltaic power generation to participate in peak regulation, which is beneficial to the management of transformer heavy overload; the reactive power regulation and reactive power support functions can be used to manage the voltage over-limit of the distribution network and improve the qualified rate of the grid voltage; the present invention can also automatically control the inverter to perform active and reactive support for the distribution network, which is beneficial to the coordinated control of distributed power generation and distribution network, and realize the integrated development of source and network.

[0075] The present invention relates to an automatic control method and device for high-proportion distributed photovoltaic power generation dispatching inverter. The device is directly inserted into the local communication interface of the photovoltaic inverter, and the device operation information is obtained by communicating with the inverter to perform real-time power control on the inverter. At the same time, the operation information can be converted and forwarded, thereby realizing large-scale high-proportion distributed photovoltaic adaptive control and cluster aggregation coordinated control, and supporting the coordinated development of distributed photovoltaic power generation and distribution network.

[0076] In an example implementation, the step of performing droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency in S120 to cooperate with active power regulation of the power grid includes:

[0077] When the AC side frequency is in the frequency regulation response area, if the AC side frequency is less than the first frequency regulation boundary value, the distributed photovoltaic inverter active power is drooped based on the AC side frequency and the first droop control relationship to cooperate with the active power regulation of the power grid;

[0078] If the AC side frequency is greater than or equal to the first frequency modulation boundary value, the distributed photovoltaic inverter active power is drooped based on the AC side frequency and the second droop control relationship to cooperate with the active power regulation of the power grid;

[0079] The absolute value of the slope of the curve corresponding to the first droop control relationship is smaller than the absolute value of the slope of the curve corresponding to the second droop control relationship.

[0080] In this example implementation, the frequency control response area refers to the frequency control area outside the frequency control dead zone, and the frequency control dead zone refers to the active output non-response area of ​​the control system. Taking into account the different active output reduction rates at different frequencies, this example divides the active output reduction area into two stages by setting the first frequency modulation boundary value, and uses different reduction rates to regulate the active output in different stages, so that the inverter can better cooperate with the peak load regulation of the power grid. Specifically, in the frequency control response area within the first frequency modulation boundary value, the first droop control relationship is used to control the active output of the inverter, and when the frequency on the AC side is greater than the first frequency modulation boundary value, the second droop control relationship is used to control the active output of the inverter. The absolute value of the slope of the curve corresponding to the first droop control relationship is smaller than the absolute value of the slope of the curve corresponding to the second droop control relationship. In this way, when the frequency on the AC side is low, a smaller reduction rate is used to control the active output. When the frequency on the AC side exceeds the first frequency regulation boundary value, that is, when the grid frequency is high, the photovoltaic active output is controlled to be reduced by a larger amplitude. Through this segmented active power reduction, the distributed photovoltaic power generation system can better cooperate with the peak regulation of the grid and achieve better peak regulation effect.

[0081] In an example implementation, the step of performing droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage in S130 to coordinate reactive power regulation of a power grid includes:

[0082] When the AC side voltage is in the voltage regulation response area, performing droop control on the reactive power of the distributed photovoltaic inverter based on the AC side voltage and a third droop control relationship to cooperate with reactive power regulation of the power grid;

[0083] Among them, if the AC side voltage is higher than the maximum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the maximum voltage value of the voltage control dead zone and the first voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; if the AC side voltage is lower than the minimum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the minimum voltage value of the voltage control dead zone and the second voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; the difference between the first voltage limit and the second voltage limit is greater than the difference between the two endpoint values ​​of the voltage control dead zone.

[0084] In this example implementation, the voltage control response area refers to the voltage interval outside the voltage control dead zone, and the voltage control dead zone refers to the reactive power control non-response area of ​​the control system, which can be a voltage range centered on the rated voltage Un of the grid connection point. For example, the voltage control dead zone is [Un-ΔU, Un+ΔU]. The voltage control response area includes a high-voltage control area with a maximum voltage value higher than the voltage control dead zone and a low-voltage control area with a minimum voltage value lower than the voltage control dead zone. The first voltage limit corresponds to the maximum control capability of the high-voltage control area, and the second voltage limit corresponds to the maximum control capability of the low-voltage control area. The difference between the first voltage limit and the second voltage limit is greater than the difference between the two endpoint values ​​of the voltage control dead zone to ensure the control range of the droop control area. The first voltage limit and the second voltage limit can both be set according to the corresponding voltage safety standards and actual needs. In the high-voltage control area and the low-voltage control area, the reactive power droop control of the inverter can be performed based on the current AC side voltage and the third droop control relationship. The third droop control relationship can form a corresponding droop control curve / straight line. For the high-voltage control area, the ratio of the difference between the maximum voltage value of the voltage control dead zone and the first voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter can be used as the slope of the control curve to perform corresponding droop control, so as to perform reactive voltage support; for the low-voltage control area, the ratio of the difference between the minimum voltage value of the voltage control dead zone and the second voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter can be used as the slope of the control curve to perform corresponding droop control, so as to perform reactive voltage support. This example realizes the reactive power support of distributed photovoltaic to the power grid through adaptive droop control of the high-voltage control area and the low-voltage control area, which is beneficial to the control of voltage over-limit of the distribution network and improves the qualified rate of the power grid voltage.

[0085] In an example implementation, the step of performing droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to coordinate reactive power regulation of the power grid in S130 further includes:

[0086] If the distributed photovoltaic inverter absorbs reactive power of the power grid at the maximum reactive power regulation value and the AC side voltage is higher than the first voltage limit, the distributed photovoltaic inverter is controlled to absorb reactive power at the maximum reactive power regulation value, and the distributed photovoltaic inverter is controlled to droop the active power based on the AC side voltage and the fourth droop control relationship to cooperate with reactive power regulation of the power grid;

[0087] The fourth droop control relationship is determined based on the ratio of the difference between the first voltage limit and the preset maximum adjustable voltage to the maximum reactive power regulation value of the distributed photovoltaic inverter.

[0088] In this example implementation, considering that the line resistance and reactance of the distribution network are relatively large, the active power and reactive power of distributed photovoltaic power generation will affect the voltage value of the inverter grid connection point, so the grid voltage can be adjusted by active output control. Specifically, when the distributed photovoltaic inverter absorbs the reactive power of the grid at the maximum reactive adjustment value, the AC side voltage is still higher than the first voltage limit, that is, when the reactive power regulation capacity is exhausted and the current measurement is still overvoltage, the distributed photovoltaic inverter can be controlled to absorb reactive power at the maximum reactive adjustment value, and the active power of the distributed photovoltaic inverter can be drooped based on the AC side voltage and the fourth droop control relationship, so as to assist reactive control through active output control to prevent overvoltage on the AC side. The first voltage limit can be the overvoltage limit on the AC side. The fourth droop control relationship can be a droop control curve / straight line, and the slope of the corresponding droop control curve can be determined based on the ratio of the difference between the first voltage limit and the preset maximum adjustable voltage to the maximum reactive power regulation value of the distributed photovoltaic inverter, and this curve can be used to perform auxiliary active power regulation when the reactive power regulation capacity is exhausted, so as to avoid overvoltage on the AC side and improve the voltage regulation capacity of the device. The power-voltage droop control in this example is mainly based on reactive voltage control, supplemented by active voltage control. The voltage on the AC side of the inverter prioritizes regulating the reactive power of the inverter. If the reactive output capacity of the inverter is exhausted and the AC side is still overvoltage, the active output should be gradually reduced to prevent overvoltage on the power grid.

[0089] In an exemplary implementation, the step S120 of performing droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid further includes:

[0090] If the AC side frequency is greater than or equal to the second frequency regulation boundary value and less than or equal to the maximum limit of the frequency regulation response area, the active power of the distributed photovoltaic inverter is controlled based on the active power corresponding to the maximum active power reduction amount;

[0091] Among them, the second frequency modulation boundary value is greater than or equal to the first frequency modulation boundary value, and the maximum active power reduction amount is determined based on the rated power of the distributed photovoltaic inverter and the maximum reduction ratio configured by the user.

[0092] In this example implementation, the second frequency modulation demarcation value and the maximum limit value of the frequency control response zone can be set according to actual conditions, and the two are not equal and the latter is greater than the former and the latter. For example, the second frequency modulation demarcation value is set to 50.3, and the maximum limit value of the frequency control response zone is set to 50.5. The maximum active power reduction amount can be determined based on the maximum reduction ratio configured by the user, such as the maximum active power reduction amount is the product of the rated power and the maximum reduction ratio. When the frequency on the AC side is between the second frequency modulation demarcation value and the maximum limit value of the frequency control response zone, the active power output of the inverter can be controlled based on the pre-configured maximum active power reduction amount, so that the maximum active power output can be reduced within a certain frequency range, so that a certain buffer can be provided before the photovoltaic power generation stops, and the frequent start and stop phenomenon caused by direct shutdown after reaching a certain frequency can be avoided.

[0093] In an exemplary implementation, the step S130 of performing droop control on the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid further includes:

[0094] If the AC side voltage is lower than the second voltage limit, the distributed photovoltaic inverter is controlled to output reactive power to the power grid at a maximum reactive power regulation value.

[0095] In this example implementation, the second voltage limit may be the voltage when the reactive power emitted by the photovoltaic inverter reaches a maximum value. If the AC side voltage continues to decrease, that is, the AC side voltage is lower than the second voltage limit, the photovoltaic inverter performs reactive voltage support according to the maximum reactive power regulation value to provide maximum reactive voltage support under low grid voltage conditions.

[0096] In an exemplary implementation, after obtaining the AC side frequency and the AC side voltage of the distributed photovoltaic inverter in S110, the method further includes:

[0097] Determine whether the AC side frequency is in a frequency control dead zone, and if so, control the operation of the distributed photovoltaic inverter based on a maximum power tracking mode;

[0098] Determine whether the AC side voltage is in a voltage regulation dead zone, and if so, control the distributed photovoltaic inverter to operate based on a maximum power tracking mode and a power factor of 1.

[0099] In this example implementation, when the AC side frequency is in the frequency regulation dead zone, the photovoltaic inverter is controlled to operate based on the maximum power point tracking (MPPT) mode, that is, the photovoltaic inverter operates in the maximum power tracking state, and the power is the MPPT power point. When the AC side voltage is in the voltage regulation dead zone, the photovoltaic inverter is controlled to operate based on the maximum power tracking mode and the power factor is 1 (that is, the reactive output is 0). This example can ensure the maximum power output of the photovoltaic system in the regulation dead zone.

[0100] In an exemplary implementation, before obtaining the AC side frequency and the AC side voltage of the distributed photovoltaic inverter in S110, the method further includes:

[0101] Receive active and / or reactive power control instructions sent by the regional terminal or remote monitoring subsystem;

[0102] The active and / or reactive power of the distributed photovoltaic inverter is controlled and adjusted based on the active and / or reactive control instructions.

[0103] In this example implementation, the active and reactive power of the inverter can be regulated based on the superior instruction, so that the distributed photovoltaic participates in the centralized regulation of the power grid. Specifically, the automatic regulation device of each photovoltaic inverter receives the active regulation instruction and / or reactive regulation instruction sent by the regional terminal or the remote monitoring subsystem through the communication interface, and the instruction may include a regulation value or a regulation target, etc., and controls the active and reactive power of the corresponding photovoltaic inverter according to the instruction.

[0104] In an exemplary implementation, after acquiring the AC side frequency and the AC side voltage of the distributed photovoltaic inverter at S110, the method further includes:

[0105] Determining whether to perform droop control of the active power of the distributed photovoltaic inverter based on the received active power regulation mode parameters configured by the user;

[0106] If it is determined that the distributed photovoltaic inverter active power droop control is not performed, controlling the operation of the distributed photovoltaic inverter based on a maximum power tracking mode;

[0107] Determining whether to perform droop control of reactive power of the distributed photovoltaic inverter based on the reactive power control mode parameters configured by the user received;

[0108] If it is determined not to perform droop control on the reactive power of the distributed photovoltaic inverter, the distributed photovoltaic inverter is controlled to operate based on a maximum power tracking mode and a power factor of 1.

[0109] In this example implementation, the user can configure whether the active support function of the photovoltaic inverter is put into use by configuring the active control mode parameters, and can also configure whether the reactive support function of the photovoltaic inverter is put into use by configuring the reactive control mode parameters. If it is determined to be put into use, the active / reactive droop control of the inverter is performed; if the active support is not put into use, the operation of the distributed photovoltaic inverter is controlled based on the maximum power tracking mode; if the reactive support is not put into use, the operation of the distributed photovoltaic inverter is controlled based on the maximum power tracking mode and the power factor is 1. This example can provide a control entrance for users to facilitate user participation in regulation.

[0110] In an example implementation, the step of performing droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency in S120 further includes:

[0111] If the output active power of the distributed photovoltaic inverter is less than the target value, exit the droop control process, and control the operation of the distributed photovoltaic inverter in the maximum power tracking mode;

[0112] The target value is a specified proportion of the rated power of the distributed photovoltaic inverter.

[0113] In this example implementation, the target value may be a specified ratio of the rated power of the photovoltaic inverter, and the specified ratio may be a user-configured parameter, for example, the target value is 15% Pn, where Pn is the rated power of the photovoltaic inverter. When the active output of the inverter is less than the target value, the droop control process may be exited, and the inverter operation may be controlled in a normal maximum power tracking mode.

[0114] In an exemplary implementation, after acquiring the AC side frequency and the AC side voltage of the distributed photovoltaic inverter in S110, the method further includes:

[0115] If the AC side frequency exceeds the maximum limit of the frequency control response zone or the AC side voltage reaches a preset maximum adjustable voltage, the distributed photovoltaic inverter is controlled to stop generating electricity.

[0116] In this example implementation, if the AC side frequency exceeds the maximum limit of the frequency control response zone or the AC side voltage reaches a preset maximum adjustable voltage, it means that the grid does not need to supply power, and the inverter is controlled to stop generating power.

[0117] In an exemplary implementation, before receiving the active power and / or reactive power control instruction sent by the regional terminal or the remote monitoring subsystem, the method further includes:

[0118] Acquiring real-time operating data of the distributed photovoltaic inverter;

[0119] Perform encryption processing on the real-time operation data based on a power grid-specific encryption method to obtain corresponding encrypted data;

[0120] The encrypted data is sent to the regional terminal or the remote monitoring subsystem, so that the regional terminal or the remote monitoring subsystem aggregates the received encrypted data of each distributed photovoltaic inverter and sends the aggregated result to the power grid management agency.

[0121] In this example implementation, real-time operating data may include AC voltage, AC current, active power, reactive power, power factor, frequency, DC voltage, DC current, DC power, daily power generation, monthly power generation, annual power generation, total power generation, inverter temperature, inverter working status, faults or alarms and other operating information of the photovoltaic inverter. The automatic control device collects the real-time operating data of the inverter and then encrypts the operating data through the configured power-specific encryption chip before sending it out. For example, the encrypted data is sent to the regional collection terminal (such as a fusion terminal, concentrator, etc.) or the monitoring subsystem for information collection (such as similar data aggregation processing) and then sent to the power grid management agency. It can also accept the dispatching control of the power grid management agency to ensure the security of the power grid data, realize the management and control of distributed photovoltaic access to the power grid, and realize the adaptive control and cluster aggregation coordinated control of large-scale distributed photovoltaics.

[0122] The following is a specific embodiment to illustrate the specific steps of a high-ratio distributed photovoltaic inverter automatic control method of the present invention. The active power control process is as follows: Figure 3 , the reactive power control process is as follows Figure 4 As shown, the active power control process and the reactive power control process are carried out simultaneously.

[0123] The active power control process is as follows: the automatic control device monitors the active power control instructions of the upper terminal or system, determines whether a new instruction is issued, and if there is a new instruction, controls the active power output of the inverter according to the control instruction (new instruction), otherwise continues to monitor the frequency of the inverter AC side; determines whether the AC side frequency exceeds the frequency control dead zone, and if the frequency exceeds the dead zone, further determines whether the active power support function is put into use; if the frequency does not exceed the dead zone, or although it exceeds the dead zone, the active power support function is not put into use, the photovoltaic inverter operates in the maximum power tracking mode; if the frequency exceeds the dead zone and the active power support function is put into use, then Figure 5 The active power-frequency segmented droop curve shown controls the active power output of the inverter. Figure 5The horizontal axis in the middle is the frequency of the AC side of the photovoltaic inverter, that is, the grid side, and the vertical axis is the active power of the photovoltaic inverter. The active-frequency droop curve is a segmented droop curve. Under normal circumstances, the photovoltaic inverter operates in the maximum power tracking state, and the power is the MPPT power point. When the AC side frequency exceeds the dead zone f1, the active output begins to automatically decrease. The higher the frequency, the more it decreases. When the frequency is f2, the power reduction is X1%Pn. When the frequency exceeds f2, the power decreases rapidly. When the frequency reaches f3, the power reaches the maximum reduction of X2%Pn, where Pn is the rated power of the photovoltaic inverter. The frequency parameters f1, f2 and f3, as well as the reduction percentages X1 and X2 can be set. The default values ​​are f1=50.05Hz, f2=50.2Hz, f3=50.3Hz, X1=5, and X2=10. These five parameters determine the slope of the two-stage power reduction. If f1=f2 or f2=f3 is set, the two stages can be simplified into one stage. When the frequency exceeds 50.5Hz, the photovoltaic inverter stops generating electricity. When the frequency is lower than 50Hz, the photovoltaic inverter operates in the maximum power tracking state. When the inverter output active power is less than 15% Pn, it automatically exits the droop control and the photovoltaic inverter operates in the maximum power tracking state.

[0124] The reactive power control process is as follows: the automatic control device monitors the reactive power control instructions of the upper terminal or system to determine whether there are new instructions. If there are new instructions, the reactive power output of the inverter is controlled according to the control instructions (new instructions). Otherwise, the AC side voltage of the inverter is continuously monitored to determine whether the AC side voltage exceeds the dead zone. If the voltage exceeds the dead zone, a further step is taken to determine whether the reactive power support function is put into operation. If the voltage does not exceed the dead zone, or exceeds the dead zone but the reactive power support function is not put into operation, the photovoltaic inverter operates in the maximum power tracking mode with a power factor of 1. If the voltage exceeds the dead zone and the reactive power support function is put into operation, the active power output of the inverter is controlled according to the power-voltage droop curve. The power-voltage droop curve is as follows: Figure 6 shown. Figure 6The abscissa represents the AC-side voltage value of the PV inverter, the left ordinate represents the reactive power, and the right ordinate represents the active power. Un is the rated voltage at the grid connection point, and U1, U2, U3, U4, and U5 are voltage demarcation points, which can be set according to corresponding standards and actual requirements, and U1 < U2 < Un < U3 < U4 < U5. +Qmax represents the maximum reactive power output value of the inverter, and -Qmax represents the maximum reactive power absorption value of the inverter. This parameter is provided by the PV inverter manufacturer. When the AC-side voltage is within the range of U2 to U3, that is, the voltage regulation dead zone, the PV inverter operates in the power factor of 1 mode, that is, the reactive power is 0. When the AC voltage is lower than U2, the PV inverter starts to emit reactive power according to the "reactive power section I" curve. Until the voltage drops to U1, the reactive power emitted by the PV inverter reaches the maximum value +Qmax. If the voltage further decreases, the inverter performs reactive voltage support according to the maximum value +Qmax. When the AC voltage is higher than U3, the PV inverter starts to absorb reactive power according to the "reactive power section II" curve. Until the voltage rises to U4, the reactive power absorbed by the PV inverter reaches the maximum value -Qmax. If the voltage further increases, the inverter performs reactive voltage support according to the maximum value -Qmax. When the AC voltage is lower than U4, the PV inverter always operates in the maximum power tracking mode, as shown in the "active power section I". When the AC voltage is higher than U4, the inverter starts to reduce the active power output, emits active power according to the "active power section II" curve, and reduces the active power output to 0 when the voltage reaches U5, and the inverter stops generating electricity or disconnects from the grid.

[0125] Distributed photovoltaic power generation is huge in number and scattered in layout. The observability, measurability, controllability and adjustability of photovoltaic inverters are poor. The periodicity, randomness and volatility of its output have a significant impact on the dispatching and operation of the distribution network. In some special scenarios, it is easy to induce problems such as heavy overload of distribution transformers and damage to power generation and use equipment. At present, due to the relatively large installed capacity of medium-voltage grid-connected distributed photovoltaic power generation, the real-time operation information of related equipment can generally be connected to the grid dispatching and operation organization, and accept dispatching remote control and remote adjustment control. However, due to the small installed capacity and more sensitive unit investment cost of the distributed photovoltaic power generation system connected to 0.4kV, the real-time operation information of related equipment is difficult to be connected to the dispatching and operation organization of the grid company, and basically cannot be remotely controlled or remotely adjusted. It is difficult for the grid company to effectively dispatch and control such distributed photovoltaic power generation. The access of a large number of distributed photovoltaic power generation to the low-voltage distribution network will significantly change the size and direction of the power flow, causing the voltage distribution of each node on the distribution line to change significantly. Due to the large impedance of the distribution line, both the active current and reactive current of distributed photovoltaic power generation can cause line voltage fluctuations. The active output of photovoltaic power generation will raise the voltage at the end of the line, while the active load of the user will lower the voltage at the end of the line, causing voltage to exceed the limit in some cases. In order to maximize profits, distributed photovoltaic power stations generally set the export voltage protection value higher, causing overvoltage at the grid connection point and surrounding load users. In areas where a high proportion of distributed photovoltaic power generation is connected, power generation far exceeds the local load, resulting in local grid overvoltage when the photovoltaic power generation output is large, or the distribution transformer is reversed and overloaded or even overloaded, endangering the safe and stable operation of the distribution network and the safe use of users' electrical equipment.

[0126] The present invention combines the healthy development needs of the industry and proceeds from reality to propose a photovoltaic inverter automatic control method for the operation and control of high-proportion large-scale distributed photovoltaics. Other types of distributed power sources can also be expanded for use. The present invention takes into account that the line resistance and reactance of the distribution network are relatively large, so the active power and reactive power of distributed photovoltaic power generation both affect the voltage value of the inverter grid connection point. In order to ensure the benefits of distributed photovoltaic power generation as much as possible, the power-voltage droop control is mainly based on reactive voltage control, supplemented by active voltage control. The voltage on the AC side of the inverter preferentially adjusts the reactive power of the inverter. If the reactive output capacity of the inverter is exhausted and the AC side is still overvoltage, the active output should be gradually reduced until power generation stops.

[0127] Generally, photovoltaic inverters operate in the maximum power point tracking (MPPT) state, and need to reduce power when participating in active power interaction with the power grid. When the transformer in the substation is overloaded or peak regulation is required, the upper terminal or system can directly control the active power through the automatic control method of the present invention, and control the inverter to output at a specified active power or a specified percentage; the inverter active power can also be automatically controlled according to the frequency of the inverter AC side. The present invention has active power control and active power support functions, and can respond to the upper active power control instructions, or automatically adjust the active power output according to the active power-frequency droop curve.

[0128] In general, the photovoltaic inverter operates in the maximum power point tracking (MPPT) state, and the power factor is 1, that is, the reactive output is 0. When participating in the reactive voltage interaction of the power grid, it is necessary to control the reactive output according to the AC side voltage. When the AC line exceeds the limit and the voltage needs to be adjusted, the upper terminal or system can directly control the reactive power through the automatic control device of the present invention to control the inverter to output according to the specified reactive power or specified percentage, or automatically control the inverter reactive power according to the AC side voltage of the inverter. The photovoltaic inverter communication conversion and automatic control equipment has reactive power regulation and reactive support functions, and can respond to the upper reactive control instructions, or automatically adjust the reactive output according to the power-voltage droop curve (active reactive-voltage double-segmented droop curve).

[0129] The automatic control method of the present invention can simultaneously perform reactive power regulation and reactive power support functions, which is beneficial to the control of voltage over-limit in the distribution network and the improvement of the voltage qualification rate of the power grid; it can also automatically control the inverter to perform active power support and reactive power support in the distribution network, which is beneficial to the coordinated control of distributed power generation and distribution network and the realization of source-grid integration development; the present invention realizes the coordinated control of active power and reactive power of distributed photovoltaic power generation at the end of the power grid through the dual-segment droop curve control of active power-frequency and reactive power-voltage.

[0130] The automatic control method of the present invention can also be extended to other types of distributed power sources such as distributed energy storage and distributed wind power.

[0131] Example 2

[0132] Based on the same inventive concept, the present invention provides a high-ratio distributed photovoltaic inverter automatic control device, each of the automatic control devices is communicatively connected to one of the distributed photovoltaic inverters, and each of the automatic control devices includes:

[0133] A communication module, used to obtain the AC side frequency and AC side voltage of the distributed photovoltaic inverter;

[0134] An active power control module, used to perform droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid;

[0135] A reactive power control module, used for performing droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid;

[0136] Wherein, the distributed photovoltaic inverter is used for low-voltage grid connection of a distributed photovoltaic power generation system.

[0137] In this example implementation, the automatic control device can be designed to be in the form of a control rod (similar to a communication rod) or a control box of the inverter. If it is in the form of a control rod, the control rod is inserted into the local communication serial interface of the photovoltaic inverter. If it is in the form of a control box, it is similar to a "set-top box" of a photovoltaic inverter to participate in the control. It obtains the inverter operation information by communicating with the inverter, and performs real-time power control of the inverter when control is required. At the same time, it can also perform protocol conversion and information forwarding on the operation information, thereby realizing adaptive control and cluster aggregation coordinated control of large-scale distributed photovoltaics, and supporting the coordinated development of distributed photovoltaic power generation and distribution networks.

[0138] In a possible implementation manner, the active power control module includes:

[0139] A first active power control submodule is used to, when the AC side frequency is in the frequency regulation response area, if the AC side frequency is less than the first frequency regulation boundary value, perform droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency and the first droop control relationship to cooperate with the active power regulation of the power grid;

[0140] A second active power control submodule is used to perform droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency and the second droop control relationship if the AC side frequency is greater than or equal to the first frequency modulation boundary value, so as to cooperate with the active power regulation of the power grid;

[0141] The absolute value of the slope of the curve corresponding to the first droop control relationship is smaller than the absolute value of the slope of the curve corresponding to the second droop control relationship.

[0142] In a possible implementation manner, the reactive power control module includes:

[0143] A first reactive power control submodule, configured to, when the AC side voltage is in a voltage regulation response area, perform droop control on the reactive power of the distributed photovoltaic inverter based on the AC side voltage and a third droop control relationship to cooperate with reactive power regulation of a power grid;

[0144] Among them, if the AC side voltage is higher than the maximum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the maximum voltage value of the voltage control dead zone and the first voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; if the AC side voltage is lower than the minimum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the minimum voltage value of the voltage control dead zone and the second voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; the difference between the first voltage limit and the second voltage limit is greater than the difference between the two endpoint values ​​of the voltage control dead zone.

[0145] In a possible implementation manner, the reactive power control module further includes:

[0146] A second reactive power control submodule, configured to control the distributed photovoltaic inverter to absorb reactive power at the maximum reactive power regulation value if the distributed photovoltaic inverter absorbs reactive power of the power grid at the maximum reactive power regulation value and the AC side voltage is higher than the first voltage limit value, and to perform droop control of the active power of the distributed photovoltaic inverter based on the AC side voltage and the fourth droop control relationship to cooperate with reactive power regulation of the power grid;

[0147] The fourth droop control relationship is determined based on the ratio of the difference between the first voltage limit and the preset maximum adjustable voltage to the maximum reactive power regulation value of the distributed photovoltaic inverter.

[0148] In a possible implementation manner, the active power control module further includes:

[0149] A maximum active power control submodule, configured to control the active power of the distributed photovoltaic inverter based on the active power corresponding to the maximum active power reduction amount if the AC side frequency is greater than or equal to the second frequency regulation boundary value and less than or equal to the maximum limit of the frequency regulation response area;

[0150] Among them, the second frequency modulation boundary value is greater than or equal to the first frequency modulation boundary value, and the maximum active power reduction amount is determined based on the rated power of the distributed photovoltaic inverter and the maximum reduction ratio configured by the user.

[0151] In a possible implementation manner, the reactive power control module further includes:

[0152] The maximum reactive power control submodule is used to control the distributed photovoltaic inverter to output reactive power to the power grid at a maximum reactive power regulation value if the AC side voltage is lower than a second voltage limit.

[0153] In a possible implementation manner, the automatic control device further includes a dead zone control module, and the dead zone control module includes:

[0154] A dead zone active power control submodule, used to determine whether the AC side frequency is in the frequency control dead zone, and if so, to control the operation of the distributed photovoltaic inverter based on the maximum power tracking mode;

[0155] The dead zone reactive power control submodule is used to determine whether the AC side voltage is in the voltage regulation dead zone. If so, the distributed photovoltaic inverter is controlled to operate based on the maximum power tracking mode and the power factor is 1.

[0156] In a possible implementation, the automatic control device further includes a command control module;

[0157] The communication module is also used to receive active power and / or reactive power control instructions sent by the regional terminal or the remote monitoring subsystem;

[0158] The command control module is used to control and adjust the active and / or reactive power of the distributed photovoltaic inverter based on the active and / or reactive regulation command.

[0159] In a possible implementation manner, the automatic control device further includes: a mode control module, wherein the mode control module is used to:

[0160] Determining whether to perform droop control of the active power of the distributed photovoltaic inverter based on the received active power regulation mode parameters configured by the user;

[0161] If it is determined that the distributed photovoltaic inverter active power droop control is not performed, controlling the operation of the distributed photovoltaic inverter based on a maximum power tracking mode;

[0162] Determining whether to perform droop control of reactive power of the distributed photovoltaic inverter based on the reactive power control mode parameters configured by the user received;

[0163] If it is determined not to perform droop control on the reactive power of the distributed photovoltaic inverter, the distributed photovoltaic inverter is controlled to operate based on a maximum power tracking mode and a power factor of 1.

[0164] In a possible implementation manner, the automatic control device further includes:

[0165] A tracking mode control module, configured to exit the droop control process and control the operation of the distributed photovoltaic inverter in a maximum power tracking mode if the output active power of the distributed photovoltaic inverter is less than a target value;

[0166] The target value is a specified proportion of the rated power of the distributed photovoltaic inverter.

[0167] In a possible implementation manner, the automatic control device further includes:

[0168] The power generation control module is used to control the distributed photovoltaic inverter to stop generating power if the AC side frequency exceeds the maximum limit of the frequency regulation response zone or the AC side voltage reaches a preset maximum adjustable voltage.

[0169] In a possible implementation manner, the automatic control device further includes an encryption module;

[0170] The communication module is specifically used to obtain the real-time operation data of the distributed photovoltaic inverter; and is also used to send the encrypted data to the regional terminal or the remote monitoring subsystem, so that the regional terminal or the remote monitoring subsystem aggregates the received encrypted data of each distributed photovoltaic inverter and sends the aggregated result to the power grid management agency;

[0171] The encryption module is used to perform encryption processing on the real-time operation data based on a power grid-specific encryption method to obtain corresponding encrypted data.

[0172] In this embodiment, the communication module can be a plurality of communication interfaces of hardware (such as Figure 7 and Figure 8 The active control module and the reactive control module can be the main control chip of the hardware (such as Figure 7 and Figure 8 The encryption module may be an encryption chip, such as Figure 7 and Figure 8 The encryption chip in the

[0173] For example, the hardware topology of an automatic control device in the form of a control rod is as follows: Figure 7As shown, it includes a main control chip, an encryption chip and various communication interfaces. The commonly used inverter communication interface is a serial communication interface, which has multiple physical interfaces such as USB, RJ45, and pin-type. Based on this, the automatic control device in this example draws a DC power supply from the serial port to power itself. As shown in the figure, the power supply voltage VCC and the ground terminal GND are drawn from the serial port to form a power supply circuit, and the main control chip reads data from the RS485 serial bus (485A, 485B connecting wires) to achieve information interaction with the inverter. According to actual needs, various communication interfaces of the automatic control device can include 4G / 5G wireless communication, LoRa (Long Range Radio, long-distance radio) wireless communication, WiFi wireless communication, HRF (High-speed Radio Frequency, high-speed wireless communication) micro-power communication, HPLC (High-speed Power Line Communications, high-speed power line carrier) power carrier communication and other communication interfaces. It can support HRF micro-power communication and HPLC power carrier communication dual-mode communication. Power carrier communication HPLC draws an AC coupling line from the inverter AC interface as a carrier communication signal. The main control chip generally uses a digital signal processor (DSP) to facilitate interface expansion, information processing, coordinated control and data storage. The automatic control device generally communicates with the inverter through the Modbus protocol. To ensure the information security of the data interaction process, the data to be sent is encrypted by the power-specific protocol through the encryption chip, and the data is encrypted before forwarding. Communication interfaces such as LoRa wireless communication, WiFi wireless communication, HRF micro-power communication, and HPLC power carrier communication facilitate short-distance transmission and aggregation of photovoltaic inverters in a region (such as a power supply area). After being aggregated by the distribution fusion terminal, concentrator or other collection terminal (mostly located near the transformer in the area), the information is uniformly forwarded to the power grid management agency and subject to dispatch control.

[0174] If the site does not have the conditions for hard connection and direct plug-in, the automatic control device can also be designed as a separate control box mode. The hardware topology of the control box mode is as follows: Figure 8 As shown. Connected to the photovoltaic inverter via RS485 communication line ( Figure 8 A and B in the figure), a power module needs to be specially configured at this time to provide operating power for the automatic control device through 220V AC power. The power module converts AC power into 3.3V or 5V DC power. The live wire L of the AC operating power can also serve as the coupling line of the carrier communication signal, and N is the neutral wire of the AC operating power. The space size of the separate control box mode is more sufficient, and more interfaces can be expanded, such as network ports or serial ports, which can control multiple nearby photovoltaic inverters and photovoltaic grid-connected circuit breakers.

[0175] Exemplarily, the automatic control device of the present invention is as follows Fig. 9As shown in the dotted box, it may include a control module and an uplink communication interface and a downlink communication interface. The control module includes a digital signal processing chip, an encryption chip and a circuit module. The circuit module includes a power supply, a clock crystal oscillator, a timer circuit (such as a watchdog) and an LED indicator light, etc.; the uplink communication interface is used to communicate with the upper terminal (such as a regional acquisition terminal) or the system (distributed photovoltaic remote monitoring system or aggregation platform). The uplink communication interface includes RS485, HPLC, HRF micropower, LoRa, WiFi, 4G / 5G, Ethernet and other communication interfaces, and may also include an antenna; the downlink communication interface is used to communicate with the terminal device (photovoltaic inverter or photovoltaic grid-connected circuit breaker); the automatic control device can convert serial communication interfaces such as RS485 and USB into communication interfaces such as HPLC, HRF micropower, LoRa, WiFi, 4G / 5G, Ethernet, etc., and convert Modbus, custom and other communication interfaces into DL / T 634.5104, DL / T 698.45, GB / T 19582 (Modbus) and other communication protocols, so that the information of photovoltaic inverters and photovoltaic grid-connected circuit breakers is forwarded to the superior terminal or system through a unified protocol, and is subject to superior dispatching control, so as to realize the observability, measurability, controllability and adjustability of distributed photovoltaic power generation in seconds.

[0176] Low-voltage grid-connected distributed photovoltaic inverters generally support RS485 serial communication. The inverter manufacturer will randomly provide a communication stick, which is plugged into the serial communication interface (referred to as "serial port") to send the inverter's operating information to the inverter manufacturer or the monitoring cloud platform built by the construction unit through 4G / 5G communication. Distributed photovoltaic power generation users can log in to the cloud platform to view power generation operation data. In this operating mode, distributed photovoltaic power generation cannot effectively interact with the power grid management agency and is difficult to participate in power grid dispatching and control.

[0177] The present invention proposes a photovoltaic inverter automatic control method and device, which is designed to be inserted into the local communication serial interface of the photovoltaic inverter in a control stick mode, similar to the photovoltaic inverter "set-top box" participating in the control, and obtaining the inverter operation information by communicating with the inverter, and performing real-time power control on the inverter when regulation is required. At the same time, the operation information can be converted and forwarded, thereby realizing adaptive control and cluster aggregation coordinated control of large-scale distributed photovoltaics, and supporting the coordinated development of distributed photovoltaic power generation and distribution networks. The communication stick provided by the inverter manufacturer can be inserted into the tail of the photovoltaic inverter communication conversion and automatic control device, and continue to send photovoltaic operation data to the original cloud platform.

[0178] The automatic control device of the present invention can be installed at the distributed photovoltaic power generation site, and can perform communication conversion on photovoltaic inverters of different models, different interfaces, and different protocols of each inverter manufacturer, and send them out with interfaces and protocols of unified specifications, thereby improving the observable, measurable, adjustable, and controllable capabilities of the inverter. The automatic control device of the present invention extends short-distance communication interfaces such as HPLC, LoRa, and HRF micropower, which facilitates the collection and information access of photovoltaic inverters in the region without the need to lay additional communication cables; it also extends 4G / 5G interfaces to facilitate the long-distance transmission and monitoring of photovoltaic inverter information. The automatic control device of the present invention can be designed into two modes: a control rod and a control box. It can be directly plugged in for hard connection, softly connected via a communication line, and can also be connected to other equipment such as intelligent circuit breakers, suitable for different on-site scenarios.

[0179] Example 3

[0180] Based on the same inventive concept, the present invention also provides a control system for a high-ratio distributed photovoltaic inverter, including: an automatic control device for a high-ratio distributed photovoltaic inverter as described in any one of Embodiment 2.

[0181] In a possible implementation manner, the size and interface form of the automatic control device are respectively the same as the communication stick of the distributed photovoltaic inverter;

[0182] The automatic control device also includes at least one expansion interface, wherein one expansion interface has the same physical structure as the interface of the communication stick of the corresponding distributed photovoltaic inverter.

[0183] In this example implementation, in order to minimize changes to existing equipment, the automatic control device can be designed to have exactly the same size and interface form as the communication stick of the existing photovoltaic inverter, avoiding the problem of being unable to install due to inappropriate size or interface, and reducing hardware changes. The communication interface of the automatic control device can include an interface with the same physical structure as the communication stick that comes with the photovoltaic inverter, so as to avoid changes to the original communication stick interface function. The size and interface form of the automatic control device must be consistent with the communication stick that comes with the inverter, and a physical interface that is exactly the same as the inverter communication interface must be configured at the rear to facilitate the expansion and continued insertion of the communication stick. If the photovoltaic inverter has more than one RS485 interface, the built-in communication stick can also be used alone.

[0184] For example, Fig.10As shown, the control system of the present invention may include a photovoltaic inverter and a corresponding automatic control device, and may also include a regional acquisition terminal, a distributed photovoltaic remote monitoring system / aggregation platform and a power grid management agency on the superior control side. The automatic control device can be connected to the regional acquisition terminal through communication interfaces such as RS485, HPLC, HRF micropower, LoRa, WiFi, etc., and communicate with the distributed photovoltaic remote monitoring system / aggregation platform and the power grid management agency through 4G / 5G or Ethernet. The automatic control device can collect real-time operating data of the photovoltaic inverter through the RS485 interface and then send it to the superior control side. If the automatic control device is configured with a 4G / 5G interface (both the control rod mode and the control box mode are available), the acquisition terminal can be skipped and the power grid management agency can be directly communicated through 4G / 5G. It is generally used in areas far away from the regional acquisition terminal and difficult to cover by short-distance wireless communication.

[0185] Example 4

[0186] like Fig.11 As shown, the present invention also provides an electronic device, which may be a computer device, a single-chip device, an intelligent mobile device, etc. The electronic device in this embodiment may include a processor, a memory, a transceiver component, etc. The memory, the processor, and the transceiver component are connected via a bus; the memory may be used to store an execution program, and an exemplary execution program may include instructions; the processor is used to execute the instructions stored in the memory. The memory may also be used to store data, which may be called and / or modified when the instructions are executed.

[0187] The processor 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 gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, specifically suitable for loading and executing one or more instructions in a storage medium to implement the corresponding method flow or corresponding functions, so as to implement the steps of a high-proportion distributed photovoltaic inverter automatic control method in the above-mentioned embodiment.

[0188] Example 5

[0189] Based on the same inventive concept, the present invention also provides a readable storage medium, specifically an electronic device readable storage medium (Memory), which is a memory device in an electronic device for storing programs and data. It can be understood that the storage medium here can include both built-in storage media in electronic devices and, of course, extended storage media supported by electronic devices. The storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by a processor are also stored in the storage space, and these instructions can be one or more execution programs (including program codes). It should be noted that the storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. The processor loads and executes one or more instructions stored in the storage medium, which can implement the steps of a high-proportion distributed photovoltaic inverter automatic control method in the above embodiment.

[0190] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0191] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0192] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0193] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0194] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the application, but these changes, modifications or equivalent substitutions are all within the protection scope of the claims to be approved.

Claims

1. A high-ratio distributed photovoltaic inverter automatic control method, characterized in that: An automatic control device applied to the distributed photovoltaic inverter, each of the automatic control devices is communicatively connected to one of the distributed photovoltaic inverters, and the method comprises: Acquiring an AC side frequency and an AC side voltage of the distributed photovoltaic inverter; Performing droop control on the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid; Based on the AC side voltage, the reactive power of the distributed photovoltaic inverter is controlled to droop, so as to cooperate with the reactive power regulation of the power grid; Wherein, the distributed photovoltaic inverter is used for low-voltage grid connection of a distributed photovoltaic power generation system.

2. The method according to claim 1, characterized in that The droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid includes: When the AC side frequency is in the frequency regulation response area, if the AC side frequency is less than the first frequency regulation boundary value, the distributed photovoltaic inverter active power is drooped based on the AC side frequency and the first droop control relationship to cooperate with the active power regulation of the power grid; If the AC side frequency is greater than or equal to the first frequency modulation boundary value, the distributed photovoltaic inverter active power is drooped based on the AC side frequency and the second droop control relationship to cooperate with the active power regulation of the power grid; The absolute value of the slope of the curve corresponding to the first droop control relationship is smaller than the absolute value of the slope of the curve corresponding to the second droop control relationship.

3. The method according to claim 1, characterized in that The droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with the reactive power regulation of the power grid includes: When the AC side voltage is in the voltage regulation response area, performing droop control on the reactive power of the distributed photovoltaic inverter based on the AC side voltage and a third droop control relationship to cooperate with reactive power regulation of the power grid; Among them, if the AC side voltage is higher than the maximum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the maximum voltage value of the voltage control dead zone and the first voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; if the AC side voltage is lower than the minimum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the minimum voltage value of the voltage control dead zone and the second voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; the difference between the first voltage limit and the second voltage limit is greater than the difference between the two endpoint values ​​of the voltage control dead zone.

4. The method according to claim 3, characterized in that The method of performing droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid also includes: If the distributed photovoltaic inverter absorbs reactive power of the power grid at the maximum reactive power regulation value and the AC side voltage is higher than the first voltage limit, the distributed photovoltaic inverter is controlled to absorb reactive power at the maximum reactive power regulation value, and the distributed photovoltaic inverter is controlled to droop the active power based on the AC side voltage and the fourth droop control relationship to cooperate with reactive power regulation of the power grid; The fourth droop control relationship is determined based on the ratio of the difference between the first voltage limit and the preset maximum adjustable voltage to the maximum reactive power regulation value of the distributed photovoltaic inverter.

5. The method according to claim 2, characterized in that: The method of performing droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid also includes: If the AC side frequency is greater than or equal to the second frequency regulation boundary value and less than or equal to the maximum limit of the frequency regulation response area, the active power of the distributed photovoltaic inverter is controlled based on the active power corresponding to the maximum active power reduction amount; Among them, the second frequency modulation boundary value is greater than or equal to the first frequency modulation boundary value, and the maximum active power reduction amount is determined based on the rated power of the distributed photovoltaic inverter and the maximum reduction ratio configured by the user.

6. The method according to claim 3, characterized in that The method of performing droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid also includes: If the AC side voltage is lower than the second voltage limit, the distributed photovoltaic inverter is controlled to output reactive power to the power grid at a maximum reactive power regulation value.

7. The method according to claim 1, characterized in that After obtaining the AC side frequency and the AC side voltage of the distributed photovoltaic inverter, the method further includes: Determine whether the AC side frequency is in a frequency control dead zone, and if so, control the operation of the distributed photovoltaic inverter based on a maximum power tracking mode; Determine whether the AC side voltage is in a voltage regulation dead zone, and if so, control the distributed photovoltaic inverter to operate based on a maximum power tracking mode and a power factor of 1.

8. The method according to any one of claims 1 to 7, characterized in that: Before obtaining the AC side frequency and the AC side voltage of the distributed photovoltaic inverter, the method further includes: Receive active and / or reactive power control instructions sent by the regional terminal or remote monitoring subsystem; The active and / or reactive power of the distributed photovoltaic inverter is controlled and adjusted based on the active and / or reactive control instructions.

9. The method according to claim 8, characterized in that After obtaining the AC side frequency and the AC side voltage of the distributed photovoltaic inverter, the method further includes: Determining whether to perform droop control of the active power of the distributed photovoltaic inverter based on the received active power regulation mode parameters configured by the user; If it is determined that the distributed photovoltaic inverter active power droop control is not performed, controlling the operation of the distributed photovoltaic inverter based on a maximum power tracking mode; Determining whether to perform droop control of reactive power of the distributed photovoltaic inverter based on the reactive power control mode parameters configured by the user received; If it is determined not to perform droop control on the reactive power of the distributed photovoltaic inverter, the distributed photovoltaic inverter is controlled to operate based on a maximum power tracking mode and a power factor of 1.

10. The method according to claim 1, characterized in that The droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency further includes: If the output active power of the distributed photovoltaic inverter is less than the target value, exit the droop control process, and control the operation of the distributed photovoltaic inverter in the maximum power tracking mode; The target value is a specified proportion of the rated power of the distributed photovoltaic inverter.

11. The method according to claim 5 or 6, characterized in that: After obtaining the AC side frequency and the AC side voltage of the distributed photovoltaic inverter, the method further includes: If the AC side frequency exceeds the maximum limit of the frequency control response zone or the AC side voltage reaches a preset maximum adjustable voltage, the distributed photovoltaic inverter is controlled to stop generating electricity.

12. The method according to claim 8, characterized in that Before receiving the active and / or reactive power control instructions sent by the regional terminal or the remote monitoring subsystem, it also includes: Acquiring real-time operating data of the distributed photovoltaic inverter; Perform encryption processing on the real-time operation data based on a power grid-specific encryption method to obtain corresponding encrypted data; The encrypted data is sent to the regional terminal or the remote monitoring subsystem, so that the regional terminal or the remote monitoring subsystem aggregates the received encrypted data of each distributed photovoltaic inverter and sends the aggregated result to the power grid management agency.

13. An automatic control device for high-ratio distributed photovoltaic inverters, characterized in that: Each of the automatic control devices is communicatively connected to one of the distributed photovoltaic inverters, and each of the automatic control devices comprises: A communication module, used to obtain the AC side frequency and AC side voltage of the distributed photovoltaic inverter; An active power control module, used to perform droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency to cooperate with the active power regulation of the power grid; A reactive power control module, used for performing droop control of the reactive power of the distributed photovoltaic inverter based on the AC side voltage to cooperate with reactive power regulation of the power grid; Wherein, the distributed photovoltaic inverter is used for low-voltage grid connection of a distributed photovoltaic power generation system.

14. The device according to claim 13, characterized in that The active power control module comprises: A first active power control submodule is used to, when the AC side frequency is in the frequency regulation response area, if the AC side frequency is less than the first frequency regulation boundary value, perform droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency and the first droop control relationship to cooperate with the active power regulation of the power grid; A second active power control submodule is used to perform droop control of the active power of the distributed photovoltaic inverter based on the AC side frequency and the second droop control relationship if the AC side frequency is greater than or equal to the first frequency modulation boundary value, so as to cooperate with the active power regulation of the power grid; The absolute value of the slope of the curve corresponding to the first droop control relationship is smaller than the absolute value of the slope of the curve corresponding to the second droop control relationship.

15. The device according to claim 13, characterized in that The reactive power control module comprises: A first reactive power control submodule, configured to, when the AC side voltage is in a voltage regulation response area, perform droop control on the reactive power of the distributed photovoltaic inverter based on the AC side voltage and a third droop control relationship to cooperate with reactive power regulation of a power grid; Among them, if the AC side voltage is higher than the maximum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the maximum voltage value of the voltage control dead zone and the first voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; if the AC side voltage is lower than the minimum voltage value of the voltage control dead zone, the third droop control relationship is determined based on the ratio of the difference between the minimum voltage value of the voltage control dead zone and the second voltage limit to the maximum reactive power regulation value of the distributed photovoltaic inverter; the difference between the first voltage limit and the second voltage limit is greater than the difference between the two endpoint values ​​of the voltage control dead zone.

16. The device according to claim 15, characterized in that The reactive power control module further comprises: A second reactive power control submodule, configured to control the distributed photovoltaic inverter to absorb reactive power at the maximum reactive power regulation value if the distributed photovoltaic inverter absorbs reactive power of the power grid at the maximum reactive power regulation value and the AC side voltage is higher than the first voltage limit value, and to perform droop control of the active power of the distributed photovoltaic inverter based on the AC side voltage and the fourth droop control relationship to cooperate with reactive power regulation of the power grid; The fourth droop control relationship is determined based on the ratio of the difference between the first voltage limit and the preset maximum adjustable voltage to the maximum reactive power regulation value of the distributed photovoltaic inverter.

17. The device according to claim 14, characterized in that The active power control module also includes: A maximum active power control submodule, configured to control the active power of the distributed photovoltaic inverter based on the active power corresponding to the maximum active power reduction amount if the AC side frequency is greater than or equal to the second frequency regulation boundary value and less than or equal to the maximum limit of the frequency regulation response area; Among them, the second frequency modulation boundary value is greater than or equal to the first frequency modulation boundary value, and the maximum active power reduction amount is determined based on the rated power of the distributed photovoltaic inverter and the maximum reduction ratio configured by the user.

18. The device according to claim 15, characterized in that The reactive power control module further comprises: The maximum reactive power control submodule is used to control the distributed photovoltaic inverter to output reactive power to the power grid at a maximum reactive power regulation value if the AC side voltage is lower than a second voltage limit.

19. The device according to claim 13, characterized in that The automatic control device further includes a dead zone control module, and the dead zone control module includes: A dead zone active power control submodule, used to determine whether the AC side frequency is in the frequency control dead zone, and if so, to control the operation of the distributed photovoltaic inverter based on the maximum power tracking mode; The dead zone reactive power control submodule is used to determine whether the AC side voltage is in the voltage regulation dead zone. If so, the distributed photovoltaic inverter is controlled to operate based on the maximum power tracking mode and the power factor is 1.

20. The device according to any one of claims 13 to 19, characterized in that The automatic control device also includes a command control module; The communication module is also used to receive active power and / or reactive power control instructions sent by the regional terminal or the remote monitoring subsystem; The command control module is used to adjust the active and / or reactive power of the distributed photovoltaic inverter based on the active and / or reactive regulation command control.

21. The device according to claim 20, characterized in that The automatic control device further comprises: a mode control module, wherein the mode control module is used to: Determining whether to perform droop control of the active power of the distributed photovoltaic inverter based on the received active power regulation mode parameters configured by the user; If it is determined that the distributed photovoltaic inverter active power droop control is not performed, controlling the operation of the distributed photovoltaic inverter based on a maximum power tracking mode; Determining whether to perform droop control of reactive power of the distributed photovoltaic inverter based on the reactive power control mode parameters configured by the user received; If it is determined not to perform droop control on the reactive power of the distributed photovoltaic inverter, the distributed photovoltaic inverter is controlled to operate based on a maximum power tracking mode and a power factor of 1.

22. The device according to claim 13, characterized in that The automatic control device also includes: A tracking mode control module, configured to exit the droop control process and control the operation of the distributed photovoltaic inverter in a maximum power tracking mode if the output active power of the distributed photovoltaic inverter is less than a target value; The target value is a specified proportion of the rated power of the distributed photovoltaic inverter.

23. The device according to claim 17 or 18, characterized in that The automatic control device also includes: The power generation control module is used to control the distributed photovoltaic inverter to stop generating power if the AC side frequency exceeds the maximum limit of the frequency regulation response zone or the AC side voltage reaches a preset maximum adjustable voltage.

24. The device according to claim 20, characterized in that The automatic control device also includes an encryption module; The communication module is specifically used to obtain the real-time operation data of the distributed photovoltaic inverter; and is also used to send the encrypted data to the regional terminal or the remote monitoring subsystem, so that the regional terminal or the remote monitoring subsystem aggregates the received encrypted data of each distributed photovoltaic inverter and sends the aggregated result to the power grid management agency; The encryption module is used to perform encryption processing on the real-time operation data based on a power grid-specific encryption method to obtain corresponding encrypted data.

25. A control system for a high-ratio distributed photovoltaic inverter, characterized in that: include: The high-ratio distributed photovoltaic inverter automatic control device as described in any one of claims 13 to 24.

26. The system according to claim 25, characterized in that The size and interface form of the automatic control device are respectively the same as the communication stick of the distributed photovoltaic inverter; The automatic control device also includes at least one expansion interface, wherein one expansion interface has the same physical structure as the interface of the communication stick of the corresponding distributed photovoltaic inverter.

27. An electronic device, characterized in that: include: at least one processor and memory; The memory and the processor are connected via a bus; The memory is used to store one or more programs; When the one or more programs are executed by the at least one processor, the high-ratio distributed photovoltaic inverter automatic control method according to any one of claims 1 to 12 is implemented.

28. A readable storage medium, characterized in that: An execution program is stored thereon, and when the execution program is executed, the automatic control method for a high-ratio distributed photovoltaic inverter as described in any one of claims 1 to 12 is implemented.

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