Distributed photovoltaic inverter communication interface expansion device and method

Abstract

The invention discloses a distributed photovoltaic inverter communication interface expansion device and method. The distributed photovoltaic inverter communication interface expansion device comprises a power supply circuit, a Sub1G wireless SoC, a matching network and a serial communication interface, the Sub1G wireless SoC comprises a Sub1G wireless communication instance, a serial interface instance, a multi-protocol frame identification and cache module, an expansion switch module and a system parameter management module; the two serial communication interfaces are electrically connected with a serial interface instance in a Sub1G wireless SoC, and the two serial communication interfaces and the Sub1G wireless communication instance are processed in a unified mode through a multi-protocol frame recognition and cache module and instantiated into an inverter interface, an inverter manufacturer'communication bar 'communication interface and a Sub1G wireless communication interface respectively. And finally, the expansion of the inverter interface is realized through the expansion switch module. According to the invention, the communication interface of the distributed photovoltaic inverter is expanded from one path to two paths, the inverter manufacturer and the converter are respectively connected, and the problem that the communication interface and the protocol of the existing product are incompatible is solved.

Description

Technical Field

[0001] The present invention relates to the field of distributed photovoltaic inverter data communication, and in particular to a distributed photovoltaic inverter communication interface expansion device and method. Background Art

[0002] As the best clean energy at present, solar energy has always been the focus of my country's new energy development. With the strong support of national policies, the photovoltaic industry has developed rapidly. In 2022, China's new photovoltaic installed capacity will reach 87.43 million kilowatts, accounting for 32.28% of the world's total, and it is expected to reach 118.09 million kilowatts in 2023.

[0003] Distributed photovoltaics have the advantages of rich resources, simple construction, energy saving and environmental protection, and are one of the important ways of development and utilization. In 2021, the newly installed capacity exceeded that of centralized power stations for the first time. Data shows that in 2021, the newly installed capacity of centralized power stations was only 25.6GW, a year-on-year decrease of 21.66%, and a total of 198.48GW; distributed photovoltaics added 29.3GW, a year-on-year increase of 88.65%, and a total of 107.5GW, accounting for about one-third.

[0004] With the rapid development of the distributed photovoltaic industry, many brands of inverter products have appeared on the market. Due to the lack of unified standards, these products have communication interface and protocol incompatibility issues, which brings inconvenience to centralized management and is not conducive to the development of intelligent and healthy directions. Summary of the invention

[0005] The main technical problem solved by the present invention is to provide a distributed photovoltaic inverter communication interface expansion device and method, which expands the distributed photovoltaic inverter communication interface from one to two, connects the inverter manufacturer and the converter respectively, and solves the problem of incompatibility between the communication interface and the protocol of the existing products.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a distributed photovoltaic inverter communication interface expansion device, which is characterized by: comprising a power supply circuit, a Sub1G wireless SoC, a matching network and a serial communication interface; Sub1G wireless SoC includes Sub1G wireless communication instance, serial interface instance, multi-protocol frame recognition and buffering module, expansion switch module, and system parameter management module; Two serial communication interfaces are electrically connected to a serial interface instance in a Sub1G wireless SoC. The two serial communication interfaces and a Sub1G wireless communication instance are uniformly processed through a multi-protocol frame recognition and cache module and instantiated into an inverter interface, an inverter manufacturer's "communication stick" communication interface, and a Sub1G wireless communication interface, respectively. Finally, the inverter interface is expanded through an expansion switch module. Matching network: maximizes the power transfer from the wireless signal source to the load (antenna); Multi-protocol frame recognition and buffering module: provides a unified data reception and processing mechanism for two serial interfaces and one Sub1G wireless communication instance; Extension switch module: realizes the multiplexing between the inverter communication interface and the inverter manufacturer's "communication stick" communication interface and Sub1G wireless communication interface; System parameter management module: saves the parameters necessary for system operation into non-volatile memory so that they can be restored after system reset; The power supply circuit provides suitable working power for the entire device.

[0007] Furthermore, the matching network uses a T-type matching network.

[0008] Furthermore, the serial communication interface is RS385, RS232, or TTL.

[0009] Furthermore, the Sub1G wireless SoC adopts STM32WL33C8.

[0010] Furthermore, the data receiving and processing mechanism is specifically as follows: when receiving data, first pre-read data from the circular cache of the communication interface, and determine whether the pre-read data contains a specific protocol frame. When a protocol frame is detected, the corresponding protocol callback function of the interface instance is called to process the data frame; the module provides a timeout mechanism for data reception, and the timeout mechanism will be triggered when the communication interface does not receive new data for a set time; the multi-protocol frame identification and caching module also provides a pre-read cache full processing mechanism. When the communication interface continuously receives data, if the data does not contain a protocol frame and the interval between receiving data is not enough to trigger the timeout mechanism, the pre-read cache will be filled, and the pre-read cache full callback function will be executed.

[0011] Furthermore, the extended switch module has contact holding, hold release and availability query functions: Among them, the inverter interface is used as a common contact, the inverter manufacturer's "communication stick" communication interface is a normally closed contact, and the Sub1G wireless communication interface is a normally open contact; Contact hold: After the contact hold function is turned on, the public contact will maintain data forwarding with the designated contact for a certain period of time; during the period when the hold function is turned on, the data received by the non-designated contact will be retained in the pre-read cache of the multi-protocol frame identification and cache module and will not be processed until the hold function times out or is actively released; Hold release: actively release the previously held contact before the contact hold timeout, and connect the common contact to the normally closed contact; Available query: Query whether the specified contact can forward data with the public contact.

[0012] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a distributed photovoltaic inverter communication interface expansion method based on the above device, the steps of which are: The inverter interface is connected to the distributed photovoltaic inverter, the inverter manufacturer's "communication stick" communication interface is connected to the inverter manufacturer, and the Sub1G wireless communication interface is connected to the distributed photovoltaic protocol converter, expanding the distributed photovoltaic inverter communication interface from one to two, and then switching through the expansion switch module to achieve multiplexing between the inverter interface and the inverter manufacturer and the distributed photovoltaic protocol converter; After receiving the inverter protocol frame, the Sub1G wireless communication interface will first query whether the current software extension switch is available. If it is not available, it will notify the multi-protocol frame identification and cache module to retain the pre-read data frame until the extension switch is available. If it is available, it will forward the inverter protocol frame to the inverter communication interface, and then turn on the hold function of the software extension switch, waiting for the return frame from the inverter interface. After completing the above operations, the Sub1G wireless communication interface will clear the pre-read cache and start the next round of receiving process; After receiving the inverter protocol frame, the inverter communication interface will forward the protocol frame to the corresponding interface according to the current connection status of the software extension switch, and then release the hold function of the software extension switch to put the inverter interface in an available state. After completing the above operations, the inverter interface will clear the pre-read cache and start the next round of receiving process.

[0013] Furthermore, the process of switch conversion by the extended switch module is as follows: the inverter interface is a common contact, the inverter manufacturer's "communication stick" communication interface is a normally closed contact, and the Sub1G wireless communication interface is a normally open contact; The extended switch module is initially in the released state. At this time, if a contact receives data, it will switch over in the corresponding multi-protocol frame recognition and cache module callback function, forward the data to the common contact, and turn on the hold function. During the hold function, if the common contact receives data, the data will be forwarded to the hold contact in the common contact callback function and then the hold function will be released; if the common contact does not receive data, the hold function will be automatically released after timeout; if the non-hold contact receives data, the data will be retained in the pre-read cache and the corresponding operation will be performed after the hold function is released.

[0014] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a computer-readable storage medium for expanding the communication interface of a distributed photovoltaic inverter, wherein the computer-readable storage medium stores program instructions that can be executed by a processor, and the program instructions are used to implement the steps of the above-mentioned expansion method.

[0015] The beneficial effects of the present invention are: 1. The present invention expands the communication interface of the distributed photovoltaic inverter from one channel to two channels without changing the software and hardware of the distributed photovoltaic inverter, affecting the original communication function of the distributed photovoltaic inverter, and requiring no additional wiring harness; the expanded first communication interface is of the same type and function as the expanded interface, providing a data communication channel for the distributed photovoltaic inverter and the inverter manufacturer's "communication stick"; the expanded second communication interface is a Sub1G wireless communication interface, providing a data communication channel between the distributed photovoltaic protocol converter and the inverter.

[0016] 2. The matching network in this application uses a T-type matching network, which is less sensitive to parasitic effects caused by changes in component layout, is more stable than other matching network types, and has a larger radiation harmonic margin.

[0017] 3. In the switch mode of the present application, since the data retained in the pre-read cache of the non-holding contacts during the hold period is the request frame in the communication protocol, and the communication device often reserves a relatively long waiting response time after sending the request frame, the request frame is cached during the switch hold period and does not affect the normal communication between devices; in addition, the active release mechanism of the common contact after receiving the response frame speeds up the switching speed of the multiplexing, so that the utilization rate of the common contact is maximized. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the description of the present invention or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the disclosed drawings without paying creative work.

[0019] Figure 1 A structural diagram of a printed circuit board of the present invention; Figure 2 is a power supply circuit diagram of the present invention; Figure 3 It is a TTL interface driving circuit diagram of the present invention; Figure 4 It is the RS485 interface driving circuit diagram of the present invention; Figure 5 It is the RS232 interface driving circuit diagram of the present invention; Figure 6 This is the embedded software architecture diagram of the present invention; Figure 7 This is a flow chart of the multi-protocol frame identification and caching module of the present invention; Figure 8 This is a schematic diagram of a software simulation switch state machine of the present invention; Fig. 9This is a flowchart of the protocol frame callback function of the present invention; Fig.10 It is a schematic diagram of the application of the present invention in a distributed photovoltaic centralized management system; Fig.11 It is a schematic diagram of the structure of the readable storage medium of the present invention. DETAILED DESCRIPTION

[0020] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. Preferred embodiments of the present invention are provided in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0021] It should be noted that, unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in this specification includes any and all combinations of one or more related listed items.

[0022] Figure 1-10 A distributed photovoltaic inverter communication interface expansion device is shown, which is characterized by including a power supply circuit, a Sub1G wireless SoC, a matching network and a serial communication interface.

[0023] Sub1G wireless SoC includes Sub1G wireless communication instance, serial interface instance, multi-protocol frame recognition and buffering module, expansion switch module, and system parameter management module; Two serial communication interfaces are electrically connected to a serial interface instance in a Sub1G wireless SoC. The two serial communication interfaces and one Sub1G wireless communication instance are uniformly processed through a multi-protocol frame recognition and cache module and instantiated as an inverter interface, an inverter manufacturer's "communication stick" communication interface, and a Sub1G wireless communication interface, respectively. Finally, the inverter interface is expanded through an expansion switch module.

[0024] Matching network: maximizes the power transfer from the wireless signal source to the load (antenna).

[0025] Multi-protocol frame recognition and cache module: provides a unified data reception and processing mechanism for two serial interfaces and one Sub1G wireless communication instance; the module first stores the data in the receive cache into the pre-read cache; provides a timeout mechanism and a cache full judgment mechanism for the pre-read cache; and can recognize data frames for multiple protocols.

[0026] Extension switch module: realizes the multiplexing between the inverter communication interface and the inverter manufacturer's "communication stick" communication interface and Sub1G wireless communication interface.

[0027] System parameter management module: save the parameters necessary for system operation into non-volatile memory so as to restore after system reset; the operating parameters saved into non-volatile memory in the present invention are as follows: photovoltaic protocol converter communication address; photovoltaic protocol converter Sub1G channel; communication interface serial interface control parameters; extended switch module holding time.

[0028] The power supply circuit provides a suitable working power supply for the entire device; the power supply circuit takes the DC output of the distributed photovoltaic inverter as input. The DC output voltage range provided by different models of distributed photovoltaic inverters is between 4.5V and 16V, so the power supply circuit should work normally within this input voltage range.

[0029] Sub1G wireless SoC is the core component of the electronic circuit part of the present invention, mainly including the following functional modules: low-power Sub1G baseband, central processing unit (CPU), flash memory (Flash), random access memory (RAM), and various common peripherals (such as serial interface, timer, analog-to-digital converter, etc.), where the number of serial interfaces needs to be at least 2. The model used in the present invention is STM32WL33C8.

[0030] The role of the matching network is to maximize the power transfer from the wireless signal source to the load (antenna). In many cases, the impedance between the signal source and the load is not matched, which can cause signal reflection and energy loss. The matching network adjusts the impedance relationship between the signal source and the load so that the most energy can be transferred from the signal source to the load. Common matching networks include L-type, π-type, T-type, etc., which are mainly composed of inductors and capacitors. The present invention uses a T-type matching network, and this matching network structure includes two series inductors and a parallel capacitor between the two inductors. Since the first component matched by the network is a series inductor, a high impedance load is provided at the harmonic, thereby achieving good harmonic suppression. In addition, the T-type matching network is less sensitive to parasitic effects caused by changes in component layout, is more stable than other matching network types, and has a larger radiated harmonic margin.

[0031] The communication interface driver circuit provides the physical layer functions and structures that comply with the specific communication interface standards. There are three main communication interface standards used by distributed photovoltaic inverters: RS485, RS232, TTL, etc.

[0032] The embedded software runs in the Sub1G wireless SoC, and is mainly composed of a Sub1G wireless communication driver, a Sub1G wireless communication instance, a serial interface driver, a serial interface instance, a multi-protocol frame recognition and cache module, an expansion switch module, a system parameter management module, etc. The embedded software of the present invention is written in C language based on the Sub1G wireless SoC development platform.

[0033] The Sub1G wireless communication example is a Sub1G wireless communication interface implemented based on the Sub1G wireless communication driver, which mainly includes Sub1G initialization, Sub1G event response function, data receiving and sending function and other functions.

[0034] The serial interface driver uses the DMA channel to send and receive data based on the underlying driver, and provides a ring buffer with adjustable size for data reception.

[0035] The serial interface instance is a serial communication interface based on a specific serial interface hardware peripheral in the Sub1G wireless SoC. In the present invention, there are two serial interface instances, which are used to connect the distributed photovoltaic inverter and the inverter manufacturer's "communication stick" respectively.

[0036] The data receiving and processing mechanism is specifically as follows: when receiving data, first pre-read data from the circular buffer of the communication interface, and determine whether the pre-read data contains a specific protocol frame. When a protocol frame is detected, the corresponding protocol callback function of the interface instance is called to process the data frame; the module provides a timeout mechanism for data reception, and the timeout mechanism will be triggered when the communication interface does not receive new data for a set period of time; the multi-protocol frame identification and caching module also provides a pre-read buffer full processing mechanism. When the communication interface continuously receives data, if the data does not contain a protocol frame and the interval between receiving data is not enough to trigger the timeout mechanism, the pre-read buffer will be filled, and the pre-read buffer full callback function will be executed.

[0037] The expansion switch module realizes the multiplexing between the inverter communication interface and the inverter manufacturer's "communication stick" communication interface and the Sub1G wireless communication interface. If the expansion switch module of the present invention is compared to a SPDT switch, the inverter interface is a common contact, the inverter manufacturer's "communication stick" communication interface is a normally closed contact, and the Sub1G wireless communication interface is a normally open contact; Contact hold: After the contact hold function is turned on, the public contact will maintain data forwarding with the designated contact for a certain period of time; during the period when the hold function is turned on, the data received by the non-designated contact will be retained in the pre-read cache of the multi-protocol frame identification and cache module and will not be processed until the hold function times out or is actively released; Hold release: actively release the previously held contact before the contact hold timeout, and connect the common contact to the normally closed contact; Available query: Query whether the specified contact can forward data with the public contact.

[0038] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a distributed photovoltaic inverter communication interface expansion method based on the above device. Figure 1-10 As shown, the steps are: The inverter interface is connected to the distributed photovoltaic inverter, the inverter manufacturer's "communication stick" communication interface is connected to the inverter manufacturer, and the Sub1G wireless communication interface is connected to the distributed photovoltaic protocol converter, expanding the distributed photovoltaic inverter communication interface from one to two, and then switching through the expansion switch module to achieve multiplexing between the inverter interface and the inverter manufacturer and the distributed photovoltaic protocol converter; After receiving the inverter protocol frame, the Sub1G wireless communication interface will first query whether the current software extension switch is available. If it is not available, it will notify the multi-protocol frame identification and cache module to retain the pre-read data frame until the extension switch is available. If it is available, it will forward the inverter protocol frame to the inverter communication interface, and then turn on the hold function of the software extension switch, waiting for the return frame from the inverter interface. After completing the above operations, the Sub1G wireless communication interface will clear the pre-read cache and start the next round of receiving process; After receiving the inverter protocol frame, the inverter communication interface will forward the protocol frame to the corresponding interface according to the current connection status of the software extension switch, and then release the hold function of the software extension switch to put the inverter interface in an available state. After completing the above operations, the inverter interface will clear the pre-read cache and start the next round of receiving process.

[0039] Among them, the process of switch conversion of the extended switch module is: the inverter interface is a common contact, the inverter manufacturer's "communication stick" communication interface is a normally closed contact, and the Sub1G wireless communication interface is a normally open contact; The extended switch module is initially in the released state. At this time, if a contact receives data, it will switch over in the corresponding multi-protocol frame recognition and cache module callback function, forward the data to the common contact, and turn on the hold function. During the hold function, if the common contact receives data, the data will be forwarded to the hold contact in the common contact callback function and then the hold function will be released; if the common contact does not receive data, the hold function will be automatically released after timeout; if the non-hold contact receives data, the data will be retained in the pre-read cache and the corresponding operation will be performed after the hold function is released.

[0040] Since the data retained in the pre-read cache of the non-holding contacts during the switch is the request frame in the communication protocol, and the communication device often reserves a relatively long waiting time for the response after sending the request frame, the request frame is cached during the switch holding period and does not affect the normal communication between devices. In addition, the active release mechanism of the public contact after receiving the response frame speeds up the switching speed of the multiplexing, maximizing the utilization rate of the public contact.

[0041] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a computer-readable storage medium for extending the communication interface of a distributed photovoltaic inverter. Fig.11 As shown, the computer-readable storage medium stores program instructions that can be executed by a processor, and the program instructions are used to implement the steps of the above-mentioned expansion method.

[0042] The functions or modules included in the device provided in the embodiments of the present disclosure can be used to execute the method described in the above method embodiments. The specific implementation thereof can refer to the description of the above method embodiments, and will not be repeated here for the sake of brevity.

[0043] The above description of various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced to each other, and for the sake of brevity, they will not be repeated herein.

[0044] In the detailed description provided in the present application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device implementation described above is only schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation. For example, units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0045] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0046] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions to enable a computer device (which can be a personal computer, server, or network device, etc.) or a processor (processor) to execute all or part of the steps of each implementation method of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

[0047] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A distributed photovoltaic inverter communication interface expansion device, characterized in that: Includes power circuit, Sub1G wireless SoC, matching network and serial communication interface; Sub1G wireless SoC includes Sub1G wireless communication instance, serial interface instance, multi-protocol frame recognition and buffering module, expansion switch module, and system parameter management module; Two serial communication interfaces are electrically connected to a serial interface instance in a Sub1G wireless SoC. The two serial communication interfaces and a Sub1G wireless communication instance are uniformly processed through a multi-protocol frame recognition and cache module and instantiated into an inverter interface, an inverter manufacturer "communication stick" communication interface, and a Sub1G wireless communication interface, respectively. Finally, the inverter interface is expanded through an expansion switch module. Matching network: maximizes power transfer from wireless signal source to load; Multi-protocol frame recognition and buffering module: provides a unified data reception and processing mechanism for two serial interfaces and one Sub1G wireless communication instance; Extension switch module: realizes the multiplexing between the inverter communication interface and the inverter manufacturer's "communication stick" communication interface and Sub1G wireless communication interface; System parameter management module: saves the parameters necessary for system operation into non-volatile memory so that they can be restored after system reset; The power supply circuit provides suitable working power for the entire device.

2. The distributed photovoltaic inverter communication interface expansion device according to claim 1, characterized in that: The matching network uses a T-type matching network.

3. The distributed photovoltaic inverter communication interface expansion device according to claim 2, characterized in that: The serial communication interface is RS385, RS232, or TTL.

4. The distributed photovoltaic inverter communication interface expansion device according to claim 1, characterized in that: The Sub1G wireless SoC adopts STM32WL33C8.

5. The distributed photovoltaic inverter communication interface expansion device according to claim 1, characterized in that: The data receiving and processing mechanism is specifically as follows: when receiving data, first pre-read data from the circular buffer of the communication interface, and determine whether the pre-read data contains a specific protocol frame. When a protocol frame is detected, the corresponding protocol callback function of the interface instance is called to process the data frame; the module provides a timeout mechanism for data reception, and the timeout mechanism will be triggered when the communication interface does not receive new data for a set period of time; the multi-protocol frame identification and caching module also provides a pre-read buffer full processing mechanism. When the communication interface continuously receives data, if the data does not contain a protocol frame and the interval between receiving data is not enough to trigger the timeout mechanism, the pre-read buffer will be filled, and the pre-read buffer full callback function will be executed.

6. The distributed photovoltaic inverter communication interface expansion device according to claim 1 is characterized in that: The switch module has contact holding, hold release and usable query functions: Among them, the inverter interface is a common contact, the inverter manufacturer's "communication stick" communication interface is a normally closed contact, and the Sub1G wireless communication interface is a normally open contact; Contact hold: After the contact hold function is turned on, the public contact will maintain data forwarding with the designated contact for a certain period of time; during the period when the hold function is turned on, the data received by the non-designated contact will be retained in the pre-read cache of the multi-protocol frame identification and cache module and will not be processed until the hold function times out or is actively released; Hold release: actively release the previously held contact before the contact hold timeout, and connect the common contact to the normally closed contact; Available query: Query whether the specified contact can forward data with the public contact.

7. A distributed photovoltaic inverter communication interface expansion method based on the device according to any one of claims 1 to 6, the steps of which are: The inverter interface is connected to the distributed photovoltaic inverter, the inverter manufacturer's "communication stick" communication interface is connected to the inverter manufacturer, and the Sub1G wireless communication interface is connected to the distributed photovoltaic protocol converter, expanding the distributed photovoltaic inverter communication interface from one to two, and then switching through the expansion switch module to achieve multiplexing between the inverter interface and the inverter manufacturer and the distributed photovoltaic protocol converter; After receiving the inverter protocol frame, the Sub1G wireless communication interface will first query whether the current software extension switch is available. If it is not available, it will notify the multi-protocol frame identification and cache module to retain the pre-read data frame until the extension switch is available. If it is available, it will forward the inverter protocol frame to the inverter communication interface, and then turn on the hold function of the software extension switch, waiting for the return frame from the inverter interface. After completing the above operations, the Sub1G wireless communication interface will clear the pre-read cache and start the next round of receiving process; After receiving the inverter protocol frame, the inverter communication interface will forward the protocol frame to the corresponding interface according to the current connection status of the software extension switch, and then release the hold function of the software extension switch to put the inverter interface in an available state. After completing the above operations, the inverter interface will clear the pre-read cache and start the next round of receiving process.

8. The distributed photovoltaic inverter communication interface expansion method according to claim 7 is characterized in that: The process of switch conversion of the switch module is as follows: the inverter interface is a common contact, the inverter manufacturer's "communication stick" communication interface is a normally closed contact, and the Sub1G wireless communication interface is a normally open contact; The extended switch module is initially in the released state. At this time, if a contact receives data, it will switch over in the corresponding multi-protocol frame recognition and cache module callback function, forward the data to the common contact, and turn on the hold function. During the hold function, if the common contact receives data, the data will be forwarded to the hold contact in the common contact callback function and then the hold function will be released; if the common contact does not receive data, the hold function will be automatically released after timeout; if the non-hold contact receives data, the data will be retained in the pre-read cache and the corresponding operation will be performed after the hold function is released.

9. A computer-readable storage medium for extending a communication interface of a distributed photovoltaic inverter, characterized in that: The computer-readable storage medium stores program instructions that can be executed by a processor, and the program instructions are used to implement the steps of the expansion method described in any one of claims 7 to 8.

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