Distributed photovoltaic inverter control system and method

Abstract

The present invention proposes a distributed photovoltaic inverter control system and method, including multiple photovoltaic inverters, an Internet of Things switch and an intelligent fusion terminal; the multiple photovoltaic inverters are connected to the intelligent fusion terminal through the Internet of Things switch. This solves the problems that the remote control scheduling instructions of the photovoltaic inverter are difficult to implement, the safety performance is insufficient, and the active and reactive power regulation capabilities are not fully utilized. Combined with the intelligent fusion terminal and the Internet of Things switch, the hand-in-hand communication method of the photovoltaic inverter and the data relay communication method based on the instructions of the Internet of Things switch are used to improve the communication efficiency, reduce the initial construction cost, and ensure the security of information communication, so as to realize the power balance and voltage intelligent control of the substation area.

Description

Technical Field

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

[0002] Photovoltaic inverter is an inverter that can convert the variable DC voltage generated by photovoltaic solar panels into AC power at the mains frequency. With the advancement of energy transformation and the development of power distribution technology, distributed photovoltaics are showing a pattern of rapid development in installed capacity. Traditional photovoltaic inverters are usually connected directly to the distribution network, relying on the control device of the photovoltaic inverter to achieve maximum power point tracking and given power factor operation, and using wireless public networks or short-distance wireless Bluetooth communication methods to achieve remote control of the electrical quantity of the photovoltaic inverter.

[0003] With the rapid development of distributed power sources represented by distributed photovoltaics, large-scale distributed photovoltaics are connected to the distribution network, which has a great impact on the voltage level, short-circuit capacity, relay protection, power supply reliability and power quality of the distribution network. The traditional "passive and passive" distribution network has low access perception and remote control capabilities for photovoltaic inverters. It usually uses wireless public networks or short-distance wireless Bluetooth communication methods to achieve remote control of photovoltaic inverter electrical quantities. It is difficult to implement remote control dispatching instructions for photovoltaic inverters, and the safety performance is low.

[0004] In the existing distributed photovoltaic inverter control technology, each photovoltaic inverter is usually connected to the low-voltage distribution network in a disorderly manner by adjusting the grid-connected AC voltage, active power, reactive power, power factor, and power generation. There are the following disadvantages when using it:

[0005] 1. Each photovoltaic inverter does not take into account the information such as the power generation of the photovoltaic inverters connected to the distribution network in the adjacent area. The unorganized adjustment of the photovoltaic inverter alone will cause voltage fluctuations and active power fluctuations in the distribution network, thereby causing the power quality of the distribution network to deteriorate.

[0006] 2. With the increase of power load, the reactive power demand of distribution network increases. Although photovoltaic inverter has reactive power regulation and power factor regulation functions, photovoltaic inverter cannot obtain the real-time reactive power demand of low-voltage distribution network. It usually guarantees its own specific power factor, which wastes the reactive power regulation ability of photovoltaic inverter.

[0007] These issues are what need to be considered when large-scale distributed photovoltaic inverters are connected to low-voltage distribution networks.

[0008] In addition, the existing distributed photovoltaic inverter control technology usually detects the voltage of its own grid connection point, directly connects to the distribution network after meeting the grid connection conditions, and realizes remote control through the APP developed by each manufacturer. There are the following disadvantages when using it:

[0009] 1. Each photovoltaic inverter only detects the voltage at its own grid connection point and then directly connects to the low-voltage distribution network. The master station of the distribution network has insufficient perception of the photovoltaic inverter access and operating status.

[0010] 2. The remote control of photovoltaic inverters is usually carried out through wireless public networks or Bluetooth, without considering information security encryption, and is vulnerable to communication attacks against distributed photovoltaic inverters.

[0011] 3. The distribution network master station has not established communication with the photovoltaic inverter, and cannot realize remote dispatch control and protection functions. It only relies on the photovoltaic inverter's own operation strategy and protection strategy to achieve grid-connected operation, wasting the photovoltaic inverter's ability to actively participate in active peak regulation and reactive power compensation.

[0012] These issues are what need to be considered when large-scale distributed photovoltaic inverters are connected to low-voltage distribution networks.

[0013] Therefore, there is an urgent need for a solution to improve the measurability, controllability and safety performance of photovoltaic inverters. Summary of the invention

[0014] In view of the defects and shortcomings of the prior art, the present invention proposes a distributed photovoltaic inverter control system and method to solve the problems of difficult implementation of remote control scheduling instructions of photovoltaic inverters, insufficient safety performance, and underutilized active and reactive power regulation capabilities. By combining the intelligent fusion terminal and the IoT switch, the hand-in-hand communication mode of the photovoltaic inverter and the data relay communication mode based on instructions of the IoT switch are used to improve communication efficiency, reduce initial construction costs, ensure information communication security, and realize power balance and voltage intelligent control in the substation area.

[0015] The present invention specifically adopts the following technical solutions:

[0016] A distributed photovoltaic inverter control system, characterized in that it comprises: a plurality of photovoltaic inverters, an Internet of Things switch and an intelligent fusion terminal; the plurality of photovoltaic inverters are respectively connected to the intelligent fusion terminal through the Internet of Things switch.

[0017] Furthermore, each of the photovoltaic inverters is equipped with: an inverter controller with at least 2 RS485 interfaces; the IoT switch is at least connected with: an RS485 communication module with at least 2 RS485 interfaces and an HPLC carrier communication module; multiple photovoltaic inverters and IoT switches are hand-in-hand connected through RS485 interfaces to form a ring network; the intelligent fusion terminal is connected to the IoT switch through HPLC.

[0018] Furthermore, the power output end of the IoT switch is electrically connected to the 380V power distribution network in the substation, and the power input end is electrically connected to the photovoltaic inverter.

[0019] Furthermore, the photovoltaic inverter is connected to the inverter control device and the data acquisition device respectively, and the inverter control device is connected to the data acquisition device, the data calculation device and the data transmission device respectively; the display device is connected to the data acquisition device and the data transmission device respectively.

[0020] Furthermore, the intelligent fusion terminal has a built-in security encryption chip to support terminal self-protection; the IoT switch is provided with a security encryption chip to extend the security boundary of photovoltaic control data communication to the IoT switch data collection side.

[0021] Furthermore, the data acquisition device integrates the three-phase photovoltaic inverter into the voltage of the AC power distribution network. U a 、U b 、U c , current fed into the AC distribution network i al 、i bl 、i cl , PV DC voltage, PV DC current i dc , collect and send to the inverter control device, the inverter control device cooperates with the data calculation device to calculate the current power generation, active power, reactive power and power factor electrical quantity data, and sends it to the IoT switch through the data transmission device, and sends the relevant display data to the display device. For data that does not need to be calculated, it includes: the voltage of the three-phase photovoltaic inverter connected to the AC distribution network U a 、U b 、U c , current fed into the AC distribution network i al 、i bl 、i cl , PV DC voltage, PV DC current i dc The data is directly sent from the data acquisition device to the display device, and the real-time operation status data of the photovoltaic inverter is displayed through the display device; the IoT switch aggregates the data of each photovoltaic inverter, and locally parses the contents of the data packets uploaded by each photovoltaic inverter through the RS485 communication module of the IoT switch, determines whether there is any photovoltaic inverter operation status data that does not meet the grid-connected requirements, performs protection actions on the spot, and then packages it into a data format adapted to the HPLC communication method and transmits it to the intelligent fusion terminal.

[0022] Furthermore, the intelligent fusion terminal responds to the dispatching instruction or calculates the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter locally to meet the functions of AC voltage stability, active power fluctuation suppression, reactive power unified compensation and power factor centralized regulation in the area; the intelligent fusion terminal sends the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter to the IoT switch through the HPLC communication method, and the IoT switch distributes the given values ​​of the photovoltaic inverter to the corresponding photovoltaic inverter and its supporting control device. The inverter control device adjusts the internal control parameters and drive signals according to the obtained grid-connected voltage, power generation, active power, reactive power and power factor given values, so as to achieve the purpose of adjusting the grid-connected voltage, power generation, active power, reactive power and power factor according to the dispatching requirements.

[0023] Furthermore, the data communication method includes the following steps:

[0024] Step S1: When the photovoltaic inverter device is ready to be connected to the power distribution network for power generation, the photovoltaic inverter device collects photovoltaic input voltage, input current, output voltage, output current electrical quantity data, calculates and obtains current power generation, active power, reactive power and power factor electrical quantity data, and packages the above data and sends it to the IoT switch in RS485 mode;

[0025] Step S21: The communication module of the IoT switch collects the current photovoltaic operation data sent by the photovoltaic inverter device in accordance with the RS485 communication mode, parses the data packet locally, analyzes the current power generation, active power, reactive power and power factor electrical quantity data information, and determines whether it is necessary to perform protection actions on site, including: island protection, overload protection, overvoltage protection and undervoltage protection; and packages the data packet in accordance with the HPLC communication mode and sends it to the intelligent fusion terminal;

[0026] Step S3: After the intelligent fusion terminal collects the photovoltaic inverter operation data sent by the IoT switch, it uploads the data packet to the cloud master station; the intelligent fusion terminal responds to the dispatch instruction or calculates the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter locally, and sends the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter to the IoT switch in accordance with the HPLC or RS485 communication method;

[0027] Step S4: After the IoT switch communication module collects the given value data packets of each photovoltaic inverter device sent by the intelligent fusion terminal, it distributes the data packets to the corresponding photovoltaic inverter and its supporting control device;

[0028] Step S5: The photovoltaic inverter control device adjusts internal control parameters according to the obtained grid-connected voltage, power generation, active power, reactive power, and power factor given values ​​to achieve the purpose of regulating the grid-connected voltage, power generation, active power, reactive power, and power factor according to the scheduling requirements.

[0029] Further, step S21 is replaced by step S22: the communication module of the IoT switch is adapted through the protocol, and the fusion terminal forwards the call communication instruction issued by the master station to the IoT switch. The IoT switch receives the port information in the request frame data field, and collects the data packets sent by the photovoltaic inverter device in accordance with the RS485 communication method through data relay, packages the data in the format of the response frame, and copies and uploads it to the intelligent fusion terminal, and does not perform parsing locally on the IoT switch.

[0030] The present invention and its preferred embodiments have the following advantages or beneficial effects:

[0031] 1. Through protocol adaptation of IoT switches, data relay is realized, so as to achieve the purpose of transmitting different protocols through high-speed power carrier HPLC module, and give IoT switches the ability to manage photovoltaic inverter devices from different manufacturers.

[0032] 2. The intelligent fusion terminal comes with a security encryption chip, and the IoT switch can be equipped with a security encryption chip to extend the power information security boundary of the photovoltaic grid to the collection side of the IoT switch, ensuring the security of photovoltaic power information data from the equipment level.

[0033] 3. Using intelligent fusion terminals and IoT switches to collect, remotely control and locally protect the grid-connected voltage, power generation, active power, reactive power and power factor of distributed photovoltaic inverters, is conducive to maintaining the voltage stability of the low-voltage distribution network, suppressing active power fluctuations, achieving the purpose of regulating the given reactive power and target power factor, and reducing line losses.

[0034] 4. One IoT switch can be used to collect grid-connected information of multiple inverters, which reduces the construction cost and subsequent operation and maintenance cost of one IoT switch for collecting and protecting one photovoltaic inverter;

[0035] 5. Make full use of the reactive power compensation function of the photovoltaic inverter and its supporting control device, eliminating the need to build a set of reactive power compensation devices, thus reducing construction costs and subsequent operation and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0037] Figure 1 A schematic diagram of the structure of a first distributed photovoltaic inverter control system provided in an embodiment of the present invention.

[0038] Figure 2 A schematic diagram of the structure of a second distributed photovoltaic inverter control system provided in an embodiment of the present invention.

[0039] Figure 3 The figure is a schematic diagram of the control process of a distributed photovoltaic inverter according to an embodiment of the present invention.

[0040] Figure 4 The figure is a schematic diagram of the overall structure of a photovoltaic inverter and its supporting control device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] Hereinafter, the specific embodiments of the present application will be described in detail with reference to the accompanying drawings. According to these detailed descriptions, those skilled in the art can clearly understand the present application and can implement the present application. Without violating the principles of the present application, the features in the various embodiments can be combined to obtain new implementations, or certain features in certain embodiments can be replaced to obtain other preferred implementations.

[0042] In order to make the features and advantages of this patent more obvious and easy to understand, the following embodiments are specifically described in detail with the accompanying drawings as follows:

[0043] like Figure 1 As shown, the basic design scheme proposed in this embodiment includes n photovoltaic inverters, IoT switches and intelligent fusion terminals.

[0044] Among them, each photovoltaic inverter is equipped with: an inverter controller with at least 2 RS485 interfaces; the Internet of Things switch is at least connected with: an RS485 communication module with at least 2 RS485 interfaces and an HPLC carrier communication module; n photovoltaic inverters and Internet of Things switches are connected hand in hand through RS485 interfaces to form a ring network; the intelligent fusion terminal and the Internet of Things switch are connected through HPLC carrier relay communication.

[0045] Specifically, the connection method of the core part can be: the communication module of the Internet of Things switch is connected to the first RS-485 interface of the photovoltaic inverter and its supporting controller device 1, the second RS-485 interface of the photovoltaic inverter device 1 is connected to the first RS-485 interface of the photovoltaic inverter device 2, the second RS-485 interface of the photovoltaic inverter device 2 is connected to the first RS-485 interface of the photovoltaic inverter device 3, and so on, until the second RS-485 interface of the photovoltaic inverter device n is connected to the second RS-485 interface of the Internet of Things switch.

[0046] In this embodiment, the definition of the IoT switch used is basically the same as the meaning of the "IoT smart switch" in the existing conventional field, that is, the opening and closing of the switch can be remotely controlled through the Internet of Things. When specifically applied to the scenario of this embodiment, the "IoT part" is implemented using an HPLC carrier communication module (which can also be replaced by an RS485 communication method). This module is a common circuit module in this field and is not further described in this embodiment; while the "switch" part can use a circuit breaker commonly used in the field to control the on and off of the circuit and can further be equipped with a closing and opening control circuit.

[0047] In order to further realize the on-off control of the photovoltaic inverter to the power grid, the power output end of the IoT switch can be electrically connected to the 380V distribution network in the substation, and the power input end can be electrically connected to the photovoltaic inverter, which is equivalent to connecting the circuit breaker part.

[0048] By introducing relevant modules such as control and communication, it can be used to implement island protection, overvoltage protection, undervoltage protection, power statistics, remote control and telemetry, uploading and downloading electrical quantity data, and rapid isolation of photovoltaic inverters in fault conditions.

[0049] In this embodiment, the intelligent fusion terminal used is also a relatively mature device at present. It can use its own functions to respond to dispatch instructions or calculate the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter locally to meet the functions of AC voltage stability, active power fluctuation suppression, reactive power unified compensation and power factor centralized regulation in the region, as well as to monitor the power quality of the IoT switch and low-voltage distribution network, and upload data to the distribution cloud master station. The intelligent fusion terminal can further exchange data with other devices through wireless public networks.

[0050] In this embodiment, the intelligent fusion terminal is embedded with a security encryption chip to support terminal self-protection. Correspondingly, the IoT switch can be equipped with a security encryption chip to extend the security boundary of photovoltaic control data communication to the IoT switch data collection side.

[0051] like Figure 4As shown, in this embodiment, the circuit topology of the three-phase inverter involved includes but is not limited to a two-level topology, a three-level T-Type topology, a three-level flying capacitor topology, a three-level neutral point clamped topology, a multi-level clamped topology, a multi-level cascaded topology, etc., to realize the function of converting DC into three-phase AC and the functions of active power, reactive power and power factor regulation. Its controller is used to control the photovoltaic inverter to generate a voltage that meets the requirements of grid-connected access to the low-voltage distribution network, to collect electrical quantity data of photovoltaic input voltage, input current, output voltage and output current, to exchange photovoltaic inverter information with the Internet of Things switch through RS-485 communication, and to respond to the grid-connected control instructions issued by the Internet of Things switch through RS-485 communication.

[0052] In actual use, the three-phase photovoltaic inverter can be connected to the voltage of the AC distribution network through the data acquisition device. U a 、U b 、U c , current fed into the AC distribution network i al 、i bl 、i cl , PV DC voltage, PV DC current i dc , collect and send to the inverter control device, the inverter control device cooperates with the data calculation device to calculate the current power generation, active power, reactive power and power factor electrical quantity data, and sends the above data to the IoT switch through the data transmission device in RS-485 mode, and sends the relevant display data to the display device. For data that does not need to be calculated, such as the voltage of the three-phase photovoltaic inverter connected to the AC distribution network U a 、U b 、U c , current fed into the AC distribution network i al 、i bl 、i cl , PV DC voltage, PV DC current i dcThe data is directly sent from the data acquisition device to the display device, and the real-time operation status data of the photovoltaic inverter is displayed on the display device. The IoT switch aggregates the data of each photovoltaic inverter, and locally parses the contents of the data packets uploaded by each photovoltaic inverter through the RS-485 communication module of the IoT switch to determine whether there is any photovoltaic inverter operation status data that does not meet the grid connection requirements, and performs protection actions on the spot, such as overload protection, overvoltage protection, undervoltage protection, etc., and then packages it into a data format that is adapted to the HPLC communication method, and transmits it to the intelligent fusion terminal according to the HPLC communication method.

[0053] The intelligent fusion terminal responds to the dispatching instructions or calculates the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter locally to meet the functions of AC voltage stability, active power fluctuation suppression, reactive power unified compensation and power factor centralized regulation in the area. The AC intelligent fusion terminal sends the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter to the IoT switch through HPLC communication. The IoT switch distributes the given values ​​of the photovoltaic inverter to the corresponding photovoltaic inverter and its supporting control device through RS-485 communication. The control device adjusts the internal control parameters and drive signals according to the obtained grid-connected voltage, power generation, active power, reactive power and power factor given values ​​to achieve the purpose of adjusting the grid-connected voltage, power generation, active power, reactive power and power factor according to the dispatching requirements.

[0054] like Figure 2 As shown, the second distributed photovoltaic inverter control system structure provided in the embodiment of the present invention also supports a multi-IoT switch topology in which each photovoltaic inverter is connected to a corresponding IoT switch. This solution is clearer in terms of management and control logic, but the cost is higher, and the IoT switch and the intelligent fusion terminal can only support HPLC carrier communication.

[0055] like Figure 3 As shown, the communication scheme provided by the embodiment of the present invention is:

[0056] S1. When the photovoltaic inverter device is ready to be connected to the distribution network for power generation, the photovoltaic inverter device collects the photovoltaic input voltage, input current, output voltage, and output current electrical quantity data, calculates the current power generation, active power, reactive power, and power factor electrical quantity data, and packages the above data in RS-485 mode and sends it to the IoT switch.

[0057] S21, the communication module of the IoT switch collects the current photovoltaic operation data sent by the photovoltaic inverter device in accordance with the RS-485 communication method, parses the data packet locally, analyzes the current power generation, active power, reactive power and power factor electrical quantity data information, determines whether it is necessary to perform protection actions on site, such as island protection, overload protection, overvoltage protection, undervoltage protection, etc., and packages the data packet in accordance with the HPLC communication method and sends it to the intelligent fusion terminal;

[0058] S22. The communication module of the IoT switch is adapted through the protocol. The fusion terminal forwards the call communication command issued by the master station to the IoT switch. The IoT switch receives the port information in the data field of the request frame, and collects the data packets sent by the photovoltaic inverter device in accordance with the RS-485 communication method through data relay. The data is packaged in the format of the response frame and copied to the intelligent fusion terminal, and is not parsed locally on the IoT switch.

[0059] S3. After the intelligent fusion terminal collects the photovoltaic inverter operation data sent by the IoT switch, it uploads the data packet to the cloud master station. The intelligent fusion terminal responds to the dispatch instruction or calculates the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter locally, and sends the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter to the IoT switch in accordance with the HPLC or RS-485 communication method.

[0060] S4. After the IoT switch communication module collects the given value data packets of each photovoltaic inverter device sent by the intelligent fusion terminal, it distributes the data packets to the corresponding photovoltaic inverter and its supporting control device.

[0061] S5. The control device adjusts the internal control parameters according to the obtained grid-connected voltage, power generation, active power, reactive power and power factor given values ​​to achieve the purpose of regulating the grid-connected voltage, power generation, active power, reactive power and power factor according to the scheduling requirements.

[0062] Among them, for the second step, if the following Figure 1 For the topology shown, the S21 solution is generally selected. The corresponding first communication method is that the photovoltaic inverter device parses the collected data packets locally and then repackages and uploads them to the intelligent fusion terminal;

[0063] If you use Figure 2For the topology shown in the figure, the S22 solution is generally selected. The corresponding second communication method is that the communication module of the IoT switch is adapted through the protocol, and the fusion terminal forwards the call communication command issued by the master station to the IoT switch. The IoT switch receives the port information in the request frame data field, and collects the data packets sent by the photovoltaic inverter device in accordance with the RS-485 communication method through data relay. The data is packaged in the format of the response frame and copied to the intelligent fusion terminal, and is not parsed locally in the IoT switch.

[0064] This patent is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of distributed photovoltaic inverter control systems and methods under the inspiration of this patent. All equal changes and modifications made according to the scope of the patent application of the present invention should be covered by this patent.

Claims

1. A distributed photovoltaic inverter control system, characterized in that: include: Multiple photovoltaic inverters, IoT switches and intelligent fusion terminals; The plurality of photovoltaic inverters are connected to the intelligent fusion terminal through the IoT switch respectively; Each of the photovoltaic inverters is equipped with: an inverter controller with at least 2 RS485 interfaces; the IoT switch is at least connected with: an RS485 communication module with at least 2 RS485 interfaces and an HPLC carrier communication module; a plurality of the photovoltaic inverters and IoT switches are connected hand in hand through the RS485 interfaces to form a ring network; the intelligent fusion terminal is connected to the IoT switch through HPLC; the photovoltaic inverter is respectively connected to the inverter control device and the data acquisition device, and the inverter control device is respectively connected to the data acquisition device, the data calculation device and the data transmission device; the display device is respectively connected to the data acquisition device and the data transmission device; The data acquisition device integrates the three-phase photovoltaic inverter into the voltage of the AC power distribution network U a 、U b 、U c , current fed into the AC distribution network i al 、i bl 、i cl , PV DC voltage, PV DC current i dc , collect and send to the inverter control device, the inverter control device cooperates with the data calculation device to calculate the current power generation, active power, reactive power and power factor electrical quantity data, and sends it to the IoT switch through the data transmission device, and sends the relevant display data to the display device. For data that does not need to be calculated, it includes: the voltage of the three-phase photovoltaic inverter connected to the AC distribution network U a 、U b 、U c , current fed into the AC distribution network i al 、i bl 、i cl , PV DC voltage, PV DC current i dc The data is directly sent from the data acquisition device to the display device, and the real-time operation status data of the photovoltaic inverter is displayed on the display device; the IoT switch aggregates the data of each photovoltaic inverter, and locally parses the contents of the data packets uploaded by each photovoltaic inverter through the RS485 communication module of the IoT switch, determines whether there is any operation status data of the photovoltaic inverter that does not meet the grid connection requirements, performs protection actions on the spot, and then packages it into a data format adapted to the HPLC communication mode and transparently transmits it to the intelligent fusion terminal; The intelligent fusion terminal responds to the dispatching instruction or calculates the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter locally to meet the functions of regional AC voltage stability, active power fluctuation suppression, reactive power unified compensation and power factor centralized regulation; the intelligent fusion terminal sends the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter to the IoT switch through the HPLC communication method, and the IoT switch distributes the given values ​​of the photovoltaic inverter to the corresponding photovoltaic inverter and its supporting control device. The inverter control device adjusts the internal control parameters and drive signals according to the obtained grid-connected voltage, power generation, active power, reactive power and power factor given values, so as to achieve the purpose of adjusting the grid-connected voltage, power generation, active power, reactive power and power factor according to the dispatching requirements.

2. The distributed photovoltaic inverter control system according to claim 1, characterized in that: The power output end of the IoT switch is electrically connected to the 380V power distribution network in the substation, and the power input end is electrically connected to the photovoltaic inverter.

3. The distributed photovoltaic inverter control system according to claim 1, characterized in that: The smart fusion terminal is embedded with a security encryption chip to support the terminal's own protection; the IoT switch is provided with a security encryption chip to extend the security boundary of photovoltaic control data communication to the IoT switch data collection side.

4. The data communication method of the distributed photovoltaic inverter control system according to claim 1, characterized in that: The following steps are involved: Step S1: When the photovoltaic inverter device is ready to be connected to the power distribution network for power generation, the photovoltaic inverter device collects photovoltaic input voltage, input current, output voltage, output current electrical quantity data, calculates and obtains current power generation, active power, reactive power and power factor electrical quantity data, and packages the above data and sends it to the IoT switch in RS485 mode; Step S21: The communication module of the IoT switch collects the current photovoltaic operation data sent by the photovoltaic inverter device in accordance with the RS485 communication mode, parses the data packet locally, analyzes the current power generation, active power, reactive power and power factor electrical quantity data information, and determines whether it is necessary to perform protection actions on site, including: island protection, overload protection, overvoltage protection and undervoltage protection; and packages the data packet in accordance with the HPLC communication mode and sends it to the intelligent fusion terminal; Step S3: After the intelligent fusion terminal collects the photovoltaic inverter operation data sent by the IoT switch, it uploads the data packet to the cloud master station; the intelligent fusion terminal responds to the dispatch instruction or calculates the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter locally, and sends the grid-connected voltage, power generation, active power, reactive power and power factor given values ​​of each photovoltaic inverter to the IoT switch in accordance with the HPLC or RS485 communication method; Step S4: After the IoT switch communication module collects the given value data packets of each photovoltaic inverter device sent by the intelligent fusion terminal, it distributes the data packets to the corresponding photovoltaic inverter and its supporting control device; Step S5: The photovoltaic inverter control device adjusts internal control parameters according to the obtained grid-connected voltage, power generation, active power, reactive power, and power factor given values ​​to achieve the purpose of regulating the grid-connected voltage, power generation, active power, reactive power, and power factor according to the scheduling requirements.

5. The data communication method of the distributed photovoltaic inverter control system according to claim 4, characterized in that: Replace step S21 with step S22: the communication module of the IoT switch is adapted through the protocol, and the fusion terminal forwards the call communication instruction issued by the master station to the IoT switch. The IoT switch receives the port information in the request frame data field, and collects the data packets sent by the photovoltaic inverter device in accordance with the RS485 communication method through data relay. The data is packaged in the format of the response frame and copied to the intelligent fusion terminal for uploading, and no parsing is performed locally on the IoT switch.

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