An external communication module for a micro-inverter and a control method thereof

Abstract

This invention relates to the field of micro-inverter communication, specifically to an external communication module for a micro-inverter and its control method. Specifically, the micro-inverter has a USART communication interface fixedly embedded externally, connected to a first control unit. The external communication module includes a 4G communication device and a WIFI communication device, both pluggable at one end to the communication interface. This allows for flexible selection of a suitable external communication module based on different external communication environments, simplifying operation. Replacing the external communication module does not require disassembling the micro-inverter body, reducing maintenance costs. The 4G and WIFI communication devices internally encapsulate corresponding control units and corresponding control components capable of establishing bidirectional communication connections with the control units. The combination of the "mobile terminal and client terminal" with the "control unit and control components" enables efficient data communication transmission and efficient remote monitoring of the micro-inverter.

Description

Technical Field

[0001] This invention relates to the field of communication technology for microinverters, and more particularly to an external communication module for microinverters and its control method. Background Technology

[0002] As one of the core components of a distributed photovoltaic system, the micro-inverter is capable of transmitting and remotely monitoring its operating data in real time, which is a key link in ensuring the stable and efficient operation of the distributed photovoltaic system.

[0003] Currently, microinverters mostly use communication methods such as "power line carrier communication" or "built-in WIFI module". However, as the application scenarios of microinverters continue to expand and the demand for communication flexibility increases, traditional communication methods can no longer fully meet the requirements, as specifically shown below: 1) Wireless WIFI communication is usually achieved by using the built-in WIFI module of the micro inverter; however, the built-in WIFI module has a high degree of integration, so when the module fails, the micro inverter usually needs to be disassembled before it can be repaired, which leads to high maintenance costs. 2) Power line carrier communication has a low communication rate, which can limit remote upgrades. In addition, some areas lack basic network infrastructure. These factors will affect the realization of functions such as data transmission, remote monitoring, and fault early warning of micro-inverters.

[0004] To solve the aforementioned technical problems, it is urgent to propose an external communication module for micro-inverters and its control method. Summary of the Invention

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an external communication module for microinverters and its control method, which solves the problem of "how to reduce the maintenance cost of microinverter components while ensuring the data communication transmission efficiency and remote monitoring efficiency of microinverter components" in the process of achieving high-quality communication of microinverters.

[0006] To achieve the above objectives, the main technical solutions adopted by the present invention include: This invention provides an external communication module for a micro inverter. Specifically, the micro inverter has an integrated first control unit inside, and a USART communication interface connected to the first control unit is fixedly embedded outside the micro inverter. The external communication module includes: a 4G communication device and a WIFI communication device that are pluggable at one end; the pluggable ends of the 4G communication device and the WIFI communication device are each fixed with a communication connector adapted to the communication interface; The 4G communication device internally encapsulates: a second control unit, and a first control component capable of establishing a bidirectional communication connection with the second control unit; the first control component includes: a first Bluetooth module, a first storage chip, a first clock chip, and a 4G communication unit; The WIFI communication device internally encapsulates: a third control unit, and a second control component capable of establishing a bidirectional communication connection with the third control unit; the second control component includes: a second Bluetooth module, a second storage chip, and a second clock chip.

[0007] Optionally, the micro inverter also integrates a DC-AC conversion unit and a protection unit. The number of communication interfaces is one; the communication interface and the communication connector can be connected bidirectionally via USART.

[0008] Optionally, the first control unit encapsulates drivers adapted to 4G communication devices and WIFI communication devices respectively; The first control unit identifies and matches the 4G communication device / WIFI communication device connected to the micro-inverter, and configures parameters and establishes communication connections based on the driver program.

[0009] Optionally, the 4G communication device has a SIM card slot fixedly encapsulated inside; the WIFI communication device integrates the lwip protocol stack, and the optional modes include: AP access point mode and STA client mode.

[0010] Optionally, the second control unit communicates with the first Bluetooth module via a bidirectional SPI connection. The second control unit communicates with the first memory chip via a bidirectional SPI connection. The second control unit communicates with the first clock chip via a bidirectional I2C connection. The second control unit communicates with the 4G communication unit via a bidirectional USART connection. Furthermore, the 4G communication unit is respectively connected to: a preset communication operator and multiple servers; each server is selected to connect to a mobile terminal and a client.

[0011] Optionally, the third control unit communicates with the second Bluetooth module via a bidirectional BLE4.2 communication connection. The third control unit communicates with the second memory chip via a bidirectional SPI communication connection. The third control unit communicates with the second clock chip via a bidirectional I2C communication connection. The third control unit communicates with the APP / server via a two-way WIFI communication connection.

[0012] The present invention also provides a control method based on the aforementioned external communication module, specifically, the control method includes: S1. When the first control unit recognizes that the 4G communication device is connected to the micro inverter, it controls the network configuration status of the 4G communication device through a state machine based on a preset control method, so as to realize the server upload of the micro inverter's operating data and receive client control commands. The network configuration status includes a regular status; the regular status includes, in order: initialization status, PDP context configuration and activation status, TCP connection status, MQTT connection status, MQTT client topic subscription status, and data processing status. The preset control method includes: after the 4G communication device completes the preset operation required for the current normal state, the 4G communication device is controlled to switch to the next normal state in sequence.

[0013] Optionally, the network configuration state may also include an anomaly handling state; the preset control method may also include: When the 4G communication device is in any of the PDP context configuration and activation state, TCP connection state, or MQTT connection state, if a preset operation fails, it will return to the previous state accordingly. If a preset operation fails when the 4G communication device is in either the initialization state or the data processing state, the 4G communication device will be switched to the abnormal handling state. After performing the corresponding abnormal recovery operation based on the preset solution, the 4G communication device will be switched back to the original state.

[0014] Optionally, the control method further includes: After completing S1, when the network configuration status is in an abnormal processing state and the network is interrupted, the second control unit performs offline data storage based on the first storage chip; after the network is restored, the offline data is uploaded.

[0015] Optionally, the control method further includes: When the MCU microprocessor recognizes that the WIFI communication device is connected to the micro inverter, it controls the WIFI communication device to perform the following in sequence: system initialization, Bluetooth network configuration, data interaction and process configuration.

[0016] The beneficial effects of this application are as follows: In this application, the microinverter is externally embedded with a USART communication interface connected to the first control unit. Simultaneously, the external communication module includes a 4G communication device and a WIFI communication device, both pluggable at one end of the communication interface. This allows for flexible selection of a suitable external communication module based on different external communication environments, simplifying operation. Furthermore, replacing the external communication module does not require disassembling the microinverter body, reducing maintenance costs. In this application, the 4G communication device and the WIFI communication device are internally encapsulated with: corresponding control units, and corresponding control components that can establish a two-way communication connection with the control unit; the combination of "mobile terminal and client terminal" with "control unit and control components" can realize: efficient data communication transmission and efficient remote monitoring involved in the micro inverter. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the communication connection between a micro inverter and an external communication module according to an embodiment of the present invention. Figure 2 This is a schematic diagram illustrating the communication connection between a micro inverter and a 4G communication device according to an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the communication connection between a micro inverter and a WIFI communication device according to an embodiment of the present invention. Detailed Implementation

[0018] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0020] Example 1

[0021] This embodiment proposes an external communication module for a micro inverter; specifically... Figure 1 This is a schematic diagram illustrating the communication connection between a micro-inverter and an external communication module, as shown below. Figure 1 As shown, the micro inverter integrates a first control unit, a DC-AC conversion unit, and a protection unit. Preferably, the first control unit can be an MCU microprocessor; the DC-AC conversion unit is used to convert photovoltaic DC power to AC power in a distributed photovoltaic system; the protection unit is used to implement overcurrent, overvoltage, and overheat protection mechanisms in a distributed photovoltaic system. like Figure 1 As shown, the micro inverter is externally fixed with a USART communication interface that connects to the first control unit; preferably, the communication interface is a standardized external communication interface, specifically an aviation plug female connector; the communication interface is provided with a fastening nut and a resilient locking buckle.

[0022] In this embodiment, it should be noted that the external communication module includes a 4G communication device and a WIFI communication device that are pluggable at one end; the pluggable ends of the 4G communication device and the WIFI communication device are both fixed with a communication connector adapted to the communication interface; preferably, the communication connector is a standardized external communication connector, specifically an aviation plug male connector; the communication connector, combined with the aforementioned fastening nut and elastic locking buckle, can be firmly connected to the communication interface; The system includes one communication interface, which can be extended to connect to other wired communication methods (such as RS232, RS485, Modbus, etc.) when not connected to a communication connector, to adapt to more application scenarios. Bidirectional USART communication can be established after any communication interface is connected to any communication connector. It should be noted that the first control unit encapsulates drivers adapted for 4G and WIFI communication devices respectively. After a bidirectional USART communication connection is established between the communication interface and the corresponding communication connector, the first control unit can identify, match, and drive the 4G / WIFI communication device connected to the micro-inverter, and configure parameters and establish communication based on the driver. In this embodiment, Figure 2 This is a schematic diagram illustrating the communication connection between a microinverter and a 4G communication device, as shown below. Figure 2 As shown, the 4G communication device internally encapsulates: a second control unit, and a first control component capable of establishing a bidirectional communication connection with the second control unit; wherein, the first control component includes: a first Bluetooth module, a first storage chip, a first clock chip, and a 4G communication unit; Specifically, such as Figure 2As shown, the second control unit communicates with the first Bluetooth module via a bidirectional SPI connection; the second control unit communicates with the first memory chip via a bidirectional SPI connection; the second control unit communicates with the first clock chip via a bidirectional I2C connection; the second control unit communicates with the 4G communication unit via a bidirectional USART connection; and the 4G communication unit is connected to: a preset communication operator and multiple servers; each server is selected to communicate with either the mobile terminal or the client. It should be noted that, preferably, the second control unit can be an MCU microprocessor; as the main control unit of the 4G communication unit, the second control unit can: 1) efficiently complete network configuration, data processing, module scheduling and protocol conversion tasks; 2) monitor network status in real time; 3) cache data and trigger reconnection when the link is interrupted; and resume data transmission after the link is restored. It should be noted that the 4G communication unit supports all frequency bands of GSM, LTE-TDD, and LTE-FDD; the 4G communication unit can achieve network attachment, TCP connection, and MQTTS (two-way encrypted authentication) connection through AT commands; the 4G communication unit is compatible with local operator networks, ensuring stable network connectivity in different areas; It should be noted that, based on the first Bluetooth module, the client ID, account, password and certificate can be transmitted through the mobile APP, enabling real-time collection and display of key operating parameters of the micro inverter in local mode, and also supporting local query and export of fault logs; It should be noted that the first clock chip is used to: support wide voltage power supply and backup battery switching, and provide reliable time basis for fault tracing, operation trend analysis and data statistics; It should be noted that the first storage chip can be a Flash chip, which supports breakpoint resume function and is used to cache real-time data transmitted by the MQTTS protocol. In this embodiment, Figure 3 This is a schematic diagram illustrating the communication connection between a micro inverter and a WIFI communication device, as shown below. Figure 3 As shown, the WIFI communication device internally encapsulates: a third control unit, and a second control component capable of establishing a bidirectional communication connection with the third control unit; wherein, the second control component includes: a second Bluetooth module, a second memory chip, and a second clock chip; Specifically, such as Figure 3 As shown, the third control unit communicates with the second Bluetooth module via a bidirectional BLE4.2 communication connection; the third control unit communicates with the second memory chip via a bidirectional SPI communication connection; the third control unit communicates with the second clock chip via a bidirectional I2C communication connection; and the third control unit communicates with the APP / server via a bidirectional WIFI communication connection.

[0023] It should be noted that, preferably, the third control unit can be an MCU microprocessor; the third control unit is used to perform module communication control and function debugging through integrated AT commands; It should be noted that the second memory chip implements data storage function through Flash; It should be noted that the second Bluetooth module is used for: data interaction and control functions of the micro-inverter in local mode; It should be noted that the second clock chip obtains the network time via the NTP protocol to achieve time synchronization of the module; In this embodiment, it should be noted that the 4G communication device has a SIM card slot that is fixedly encapsulated inside. The SIM card slot can be used to insert a mobile network card to achieve mobile network connection and supports multi-band 4G / 3G / 2G network access. The WIFI communication device integrates the lwip protocol stack and has selectable modes including AP access point mode and STA client mode, which can flexibly access existing WIFI networks or self-built hotspot networks. In this embodiment, it should be noted that, for the structure of the 4G communication device and the WIFI communication device, an optional structure is as follows: the outer shell structure adopts a barrel-type one-piece molding design, using PPE+PS (polyphenylene ether + polystyrene) blend material, designed according to the IP65 protection level, to achieve complete dustproof and waterproof; the communication connector adapted to the communication interface is equipped with a silicone rubber sealing ring, which can be adapted to harsh installation environments such as outdoor rooftops, mountain wilderness, and seaside tidal flats, to ensure long-term stable operation.

[0024] In this embodiment, when the application scenario or communication requirements change, the micro-inverter is triggered to issue a disconnect command for the 4G communication device / WIFI communication device; the 4G communication device / WIFI communication device executes the corresponding disconnect command; after confirming that the data transmission of the micro-inverter has stopped, the 4G communication device / WIFI communication device is manually removed from the micro-inverter; the WIFI communication device / 4G communication device is manually installed onto the micro-inverter; the first control unit identifies and matches the WIFI communication device / 4G communication device, and configures parameters and establishes communication connection based on the driver program; thereby enabling normal communication again.

[0025] For the external communication module for the microinverter described in Embodiment 1 above, the microinverter is externally embedded with a USART communication interface connected to the first control unit. Simultaneously, the external communication module includes a 4G communication device and a WIFI communication device, both pluggable at one end to the communication interface. Therefore, it is possible to select a suitable external communication module based on different external communication environments, allowing for flexible adaptation and simple operation. When replacing the external communication module, it is not necessary to disassemble the microinverter body, reducing maintenance costs. For the external communication module for the micro-inverter described in Embodiment 1 above, the 4G communication device and the WIFI communication device internally encapsulate: a corresponding control unit, and a corresponding control component capable of establishing a bidirectional communication connection with the control unit; the combination of "mobile terminal and client terminal" with "control unit and control component" can realize: efficient data communication transmission and efficient remote monitoring involved in the micro-inverter.

[0026] Example 2

[0027] This embodiment provides a control method based on the external communication module described in the aforementioned embodiment one. Specifically, the control method includes: S1. When the first control unit recognizes that the 4G communication device is connected to the micro inverter, it controls the network configuration status of the 4G communication device through a state machine based on a preset control method, so as to realize the server upload of the micro inverter's operating data and receive client control commands. The network configuration status includes a normal status and an exception handling status. The normal status includes, in order: initialization status, PDP context configuration and activation status, TCP connection status, MQTT connection status, MQTT client topic subscription status, and data processing status. The preset control methods include: 1) After the 4G communication device completes the required preset operations for the current normal state, the 4G communication device is controlled to switch to the next normal state in sequence; 2) When the 4G communication device is in any of the following states: PDP context configuration and activation, TCP connection, and MQTT connection, if a preset operation fails, it will revert to the previous state. 3) When the 4G communication device is in either the initialization state or the data processing state, if a preset operation fails, the 4G communication device will be switched to the abnormal handling state; after performing the corresponding abnormal recovery operation based on the preset solution, the 4G communication device will be switched back to the original state.

[0028] It should be noted that the required preset operations for the initialization state include: completing hardware initialization and software parameter initialization, while no configuration errors occur; The required preset operations for PDP context configuration and activation status include: the second control unit configures the core parameters of the 4G communication unit through AT commands, performs APN configuration, network registration query, and PDP context activation; the core parameters include: PDP context number, network protocol type, SIM card operator and assigned IP address; it should be noted that if PDP context activation fails multiple times, wait 15 minutes and try again. The required default operations for TCP connection state include: configuring server IP and port, setting connection timeout and reconnection count; The required default operations for MQTT connection status include: accessing the SSL / TLS MQTT server; setting the SSL version and authentication mode of the first SSL context to 2, setting the CA root certificate, client certificate and client key; starting the MQTT service; configuring the MQTT Broker address, port, client ID, username and password, and establishing a two-way encrypted authentication MQTT connection with the server; The MQTT protocol employs a two-way encrypted authentication connection, and the specific process includes: 1) The micro inverter initiates a TLS connection request to the MQTT Broker via the 4G network, carrying the device-side root certificate; 2) The Broker returns its own server certificate to the micro inverter. The micro inverter verifies the legality of the server certificate through the locally pre-installed root certificate (verifying the certificate signature, validity period, and domain name matching). If the verification is successful, the connection continues; otherwise, the connection is terminated and switched to the exception handling state. 3) The micro inverter sends the device identity certificate and verification information signed with the private key to the Broker; 4) The Broker verifies the identity and legitimacy of the device using the pre-configured device certificate public key (verifying certificate revocation status and device permissions). If the verification is successful, two-way encrypted authentication is completed, and a secure TLS channel is established. 5) Complete the MQTT connection handshake based on the secure channel (send a CONNECT message carrying parameters such as client ID and heartbeat period).

[0029] The prerequisite operations for subscribing to the state of an MQTT client topic include: subscribing to topics published by the client to receive information in a timely manner for easy data loading; and receiving the corresponding content after successfully subscribing to a topic. The required preset operations for data processing include: the 4G communication unit encapsulates the collected micro-inverter operating data into data frames of the corresponding protocol (TCP uses custom binary frames, MQTT uses JSON format), uploads them to the server via the 4G network, and simultaneously receives client control commands forwarded by the server; control commands include, but are not limited to: handshake frames (heartbeat packets), upgrade programs, parameter acquisition and setting.

[0030] The control method further includes: After completing S1, when the network configuration status is in an abnormal processing state and the network is interrupted, the second control unit performs offline data storage based on the first storage chip; after the network is restored, the offline data is uploaded. After S1 is completed, the first Bluetooth module connects locally with the mobile APP to receive the client ID, account and password, and generate three certificates for MQTT two-way encrypted authentication; the second control unit downloads the three certificates received to the 4G communication unit based on the first Bluetooth module. The control method further includes: When the MCU microprocessor recognizes that the WIFI communication device is connected to the micro inverter, it controls the WIFI communication device to perform the following in sequence: system initialization, Bluetooth network configuration, data interaction and process configuration.

[0031] The methods involved in the aforementioned system initialization include: 1) Initialize the "bidirectional BLE4.2 communication between the third control unit and the second Bluetooth module", "bidirectional SPI communication between the third control unit and the second memory chip", and "bidirectional I2C communication between the third control unit and the second clock chip"; 2) Initialize the second clock chip and synchronize the system time; 3) Initialize the second Bluetooth module and enable Bluetooth broadcasting; 4) By reading the second storage chip, determine whether there is already network configuration information; if there is network configuration information, initialize WiFi and automatically connect to the router; if there is no network configuration information, wait for the mobile APP to perform Bluetooth network configuration.

[0032] The aforementioned methods for Bluetooth network configuration include: 1) Scan for BLE Bluetooth broadcast via mobile app; 2) Connect the mobile app to the third control unit via Bluetooth; 3) Send the WiFi SSID / password to the third control unit; 4) Receive the network configuration data and store it in the second storage chip; 5) Initialize the WiFi and connect to the router; 6) Complete network configuration and turn off BLE Bluetooth broadcast. It should be noted that the third control unit has a built-in BLE protocol stack for defining GATT services / features (used to transmit WiFi SSID / password) and for developing the interfaces corresponding to BLE broadcasting, connection, and data transmission / reception. The methods involved in the aforementioned data interaction and process configuration include: 1) The third control unit reads the microinverter's operating data via USART bidirectional communication; 2) It timestamps the acquired microinverter operating data by reading the second clock chip; 3) It stores the timestamped operating data in the second storage chip; 4) The third control unit uploads the data stored in the second storage chip to a webpage / app via WiFi; 5) The webpage / app sends control commands, and the third control unit receives the control commands via WiFi; 6) The third control unit sends the control commands to the microinverter via USART bidirectional communication; 7) The microinverter executes the received control commands. It should be noted that the third control unit has a built-in WiFi protocol stack, which can implement AP mode and STA mode (connecting to a router), and can perform TCP / UDP / MQTT communication (interacting with servers / web pages).

[0033] When abnormal situations occur in the aforementioned "system initialization, Bluetooth network configuration, data interaction and process configuration", the corresponding exception handling methods include: 1) When WiFi connection is lost, automatically retry connecting to the router; and during the disconnection, the micro inverter data is temporarily stored in the second storage chip, and the data will be uploaded in batches after WiFi is restored.

[0034] 2) If Bluetooth pairing fails and times out, restart BLE Bluetooth broadcasting and wait for the APP to reconnect; 3) When a communication anomaly occurs in the micro inverter, a retransmission mechanism is added to record the anomaly log and send the anomaly log to the second storage chip; It should be noted that the second storage chip is equipped with data verification (such as CRC) to prevent damage to network configuration information / operational data; and the USART communication is equipped with frame check bits to filter out erroneous data.

[0035] Based on the control method described in Embodiment 2 above, the combination of "mobile terminal and client terminal" with "control unit and control components" can achieve efficient data communication transmission and efficient remote monitoring involved in the micro inverter.

[0036] It should be noted that any reference numerals placed between parentheses in the claims should not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The words "a" or "an" preceding a component do not exclude the presence of a plurality of such components. The use of the terms first, second, third, etc., is for convenience only and does not indicate any order. These terms can be understood as part of the component names.

[0037] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0038] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the claims should be interpreted to include both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0039] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, then this invention should also include these modifications and variations.

Claims

1. An external communication module for a micro inverter, characterized in that, The micro inverter has an integrated first control unit inside, and a USART communication interface connected to the first control unit is fixedly embedded on the outside of the micro inverter. The external communication module includes: a 4G communication device and a WIFI communication device that are pluggable at one end; the pluggable ends of the 4G communication device and the WIFI communication device are each fixed with a communication connector adapted to the communication interface; The 4G communication device internally encapsulates: a second control unit, and a first control component capable of establishing a bidirectional communication connection with the second control unit; the first control component includes: a first Bluetooth module, a first storage chip, a first clock chip, and a 4G communication unit; The WIFI communication device internally encapsulates: a third control unit, and a second control component capable of establishing a bidirectional communication connection with the third control unit; the second control component includes: a second Bluetooth module, a second storage chip, and a second clock chip.

2. The external communication module according to claim 1, characterized in that, The micro inverter also integrates a DC-AC conversion unit and a protection unit. The number of communication interfaces is one; the communication interface and the communication connector can be connected bidirectionally via USART.

3. The external communication module according to claim 1, characterized in that, The first control unit encapsulates drivers adapted to 4G communication devices and WIFI communication devices respectively; The first control unit identifies and matches the 4G communication device / WIFI communication device connected to the micro-inverter, and configures parameters and establishes communication connections based on the driver program.

4. The external communication module according to claim 1, characterized in that, The 4G communication device has a SIM card slot fixedly encapsulated inside; the WIFI communication device integrates the lwip protocol stack, and the selectable modes include: AP access point mode and STA client mode.

5. The external communication module according to claim 1, characterized in that, The second control unit communicates with the first Bluetooth module via a bidirectional SPI connection. The second control unit communicates with the first memory chip via a bidirectional SPI connection. The second control unit communicates with the first clock chip via a bidirectional I2C connection. The second control unit communicates with the 4G communication unit via a bidirectional USART connection. Furthermore, the 4G communication unit is respectively connected to: a preset communication operator and multiple servers; each server is selected to connect to a mobile terminal and a client.

6. The external communication module according to claim 1, characterized in that, The third control unit communicates with the second Bluetooth module via a bidirectional BLE4.2 communication connection. The third control unit communicates with the second memory chip via a bidirectional SPI communication connection. The third control unit communicates with the second clock chip via a bidirectional I2C communication connection. The third control unit communicates with the APP / server via a two-way WIFI communication connection.

7. A control method based on an external communication module according to any one of claims 1 to 6, characterized in that, The control method includes: S1. When the first control unit recognizes that the 4G communication device is connected to the micro inverter, it controls the network configuration status of the 4G communication device through a state machine based on a preset control method, so as to realize the server upload of the micro inverter's operating data and receive client control commands. The network configuration status includes a regular status; the regular status includes, in order: initialization status, PDP context configuration and activation status, TCP connection status, MQTT connection status, MQTT client topic subscription status, and data processing status. The preset control method includes: after the 4G communication device completes the preset operation required for the current normal state, the 4G communication device is controlled to switch to the next normal state in sequence.

8. The control method according to claim 7, characterized in that, The network configuration status also includes an anomaly handling status; The preset control method also includes: When the 4G communication device is in any of the PDP context configuration and activation state, TCP connection state, or MQTT connection state, if a preset operation fails, it will return to the previous state accordingly. If a preset operation fails when the 4G communication device is in either the initialization state or the data processing state, the 4G communication device will be switched to the abnormal processing state. After performing the corresponding anomaly recovery operation based on the preset solution, the 4G communication device is switched back to its original state.

9. The control method according to claim 8, characterized in that, The control method further includes: After completing S1, when the network configuration status is in an abnormal processing state and the network is interrupted, the second control unit performs offline data storage based on the first storage chip; after the network is restored, the offline data is uploaded.

10. A control method based on an external communication module according to any one of claims 1 to 6, characterized in that, The control method further includes: When the MCU microprocessor recognizes that the WIFI communication device is connected to the micro inverter, it controls the WIFI communication device to perform the following in sequence: system initialization, Bluetooth network configuration, data interaction and process configuration.

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