Photovoltaic inverter integrated with carrier communication module

Abstract

The invention discloses a photovoltaic inverter integrated with a carrier communication module, which belongs to the technical field of power distribution, and comprises a main control module, a sensing detection module, a PWM (Pulse Width Modulation) signal, a linkage protection module and a control module, and is characterized in that the main control module acquires electrical parameters and physical quantities of a main power unit through the sensing detection module, and drives the main power unit to complete AC-DC conversion, and the linkage protection module realizes hardware-level protection; the communication module encrypts and converts operation data uploaded by the main control module, transmits the operation data to a monitoring center through HPLC carrier waves, receives a downlink instruction, decrypts and analyzes the downlink instruction and transmits the downlink instruction to the main control module; and the auxiliary unit module provides adaptive working voltage for each module. The problems of protocol incompatibility and communication interference resistance can be solved, and stable direct connection with a power system is achieved; accurate real-time regulation and control capability is provided, and the flexible regulation and control requirement of a power grid is Remote monitoring and intelligent diagnosis can be realized, and the operation and maintenance efficiency is improved; meanwhile, communication safety and power grid fault quick response capability are enhanced, and reliable operation of equipment and a power grid is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of power distribution technology, and specifically relates to a photovoltaic inverter with an integrated carrier communication module. Background Technology

[0002] In the current global trend of actively promoting the development of clean energy, solar photovoltaic power generation, as a sustainable and clean energy source, is being used more and more widely. As the core equipment in a photovoltaic power generation system, the photovoltaic inverter converts the direct current (DC) generated by the photovoltaic modules into alternating current (AC) for grid connection or local load use. Traditional photovoltaic inverters primarily focus on converting DC to AC power and providing basic protection functions such as overvoltage, overcurrent, and undervoltage protection. However, with the large-scale development of the photovoltaic industry and the increasing demand for intelligent energy management, inverters that only have power conversion capabilities can no longer meet the growing and more complex application requirements. As the scale of photovoltaic (PV) systems continues to expand, especially with the rapid increase in the number of distributed PV power stations (such as numerous residential and commercial rooftop PV systems), the difficulty of operation and maintenance (O&M) of PV systems has increased significantly. Traditionally, O&M personnel often need to go to the site to check data and troubleshoot each inverter. This not only consumes a lot of manpower, resources, and time, but also makes timely and effective monitoring and maintenance difficult, especially in remote areas or for large numbers of distributed power stations. In a distributed PV community with hundreds or thousands of households, if traditional O&M methods are used, if an inverter malfunctions, it may take a long time to be detected and repaired, resulting in a significant loss of power generation. Meanwhile, with the rise of the smart grid concept and the gradual construction of the energy internet, photovoltaic systems need to interact more closely and intelligently with the power grid. This requires photovoltaic inverters to upload their own operating data, such as power generation, voltage, current, and temperature, to the power grid or energy management center in real time, so as to achieve unified scheduling and optimized management of the entire energy system. Furthermore, when abnormal fluctuations occur in the power grid, the inverter needs to be able to receive instructions from the grid in a timely manner and make corresponding adjustments, such as power regulation and reactive power compensation, to ensure the stable operation of the power grid. However, traditional photovoltaic inverters lack effective communication methods and cannot conveniently and in real time achieve data interaction and instruction reception with external systems. Currently, the communication architecture of photovoltaic inverters is incomplete and protocols are not standardized, resulting in extremely poor interoperability with the State Grid power system. From a communication protocol perspective, most ordinary photovoltaic inverters are independently developed and manufactured by different companies. To ensure the uniqueness of their products, each manufacturer often uses custom communication protocols, such as proprietary Modbus protocol variants or proprietary RS485 communication formats. These protocols are incompatible with standard protocols such as DL / T698.45 used by the State Grid power distribution area data acquisition terminals, making direct data interaction with the State Grid power system impossible.

[0003] In terms of communication stability and real-time performance, ordinary photovoltaic inverters mostly rely on RS485 wired communication or wireless communication methods such as WiFi and GPRS. These methods all have obvious limitations. RS485 communication is limited by the wiring distance, and the signal attenuates severely beyond 1000 meters and is susceptible to electromagnetic interference. WiFi and GPRS are affected by the signal coverage area, and in scenarios such as remote mountainous areas and densely populated high-rise buildings, signal interruptions and low transmission rates often occur.

[0004] When the grid load is too high, the output of photovoltaic power needs to be reduced to avoid overload; when the voltage fluctuates, the reactive power needs to be adjusted by the photovoltaic inverter to stabilize the voltage. Currently, photovoltaic inverters lack corresponding hardware design and communication support, and therefore have almost no power sector control capabilities, becoming a key bottleneck restricting the coordinated development of photovoltaics and the grid. From the perspective of control hardware, the control modules of ordinary photovoltaic inverters are mostly "fixed parameter" designs, which can only passively adjust the grid connection status according to the output power of the photovoltaic modules and cannot receive external control commands. To achieve functions such as power regulation and reactive power compensation, additional equipment such as SVG (Static Var Generator) and PCS (Power Storage Converter) needs to be installed, which not only increases equipment investment but may also lead to poor control effects due to equipment compatibility issues. Due to the large peak-valley difference in grid load, reverse overload problems frequently occur. The power sector has tried to install power limiters on the inverters, but due to the asynchronous communication between the limiter and the inverter, there have been multiple instances where "the limiter has issued a power reduction command, but the inverter is still operating at full capacity," causing frequent tripping of distribution transformer switches and affecting normal electricity use for residents.

[0005] From a control communication perspective, even if photovoltaic inverters are upgraded to have basic control hardware, precise and real-time control cannot be achieved due to lengthy communication links and inconsistent protocols. Control commands from the power substation must pass through multiple stages: from the substation to the distribution area data acquisition terminal, to the protocol converter, and finally to the inverter. Delays and data losses at each stage can cause the grid state to change before the command arrives, resulting in a "control lag" problem. Furthermore, the response speed of ordinary inverters from different manufacturers to control commands varies significantly. Some older inverters have response times exceeding 10 seconds, while grid control requires a response time of less than 2 seconds. This "untimely response" significantly reduces the effectiveness of control and may even cause new problems such as grid voltage and frequency fluctuations. Summary of the Invention

[0006] The technical problem to be solved by this invention is to address the shortcomings of ordinary photovoltaic inverters by providing a photovoltaic inverter with an integrated carrier communication module. This module can solve the problems of protocol incompatibility and communication interference, and achieve stable direct connection with the power system. It has precise real-time control capabilities to meet the flexible control needs of the power grid. It can realize remote monitoring and intelligent diagnosis to improve operation and maintenance efficiency. At the same time, it strengthens communication security and rapid response capabilities to power grid faults, ensuring the reliable operation of equipment and the power grid.

[0007] This invention is achieved using the following technical solution: The photovoltaic inverter with integrated carrier communication module described in this invention mainly consists of four core parts: main power unit, control and monitoring unit, communication module, and auxiliary unit.

[0008] A photovoltaic inverter with an integrated carrier communication module is disclosed. The main control module collects the electrical parameters and physical quantities of the main power unit through the sensing and detection module, generates a PWM signal to drive it to complete AC-DC conversion, and the linkage protection module realizes hardware-level protection. The communication module encrypts and converts the operating data uploaded by the main control module, transmits it to the monitoring center via HPLC carrier, and simultaneously receives downlink commands, decrypts and parses them, and sends them to the main control module. The auxiliary unit module provides the appropriate operating voltage for each module.

[0009] The main control module and the power unit interact logically. The main control module obtains the DC side voltage and current and the AC side voltage and current in real time through the sensing and detection module, generates PWM signals to drive the power conversion module, so that the inverter outputs AC power that conforms to the grid frequency and voltage standards; at the same time, it monitors the temperature of the power devices, and triggers the protection module to cut off the output when the temperature exceeds the threshold.

[0010] The main control module periodically collects inverter operating data and sends it to the communication module via serial port. The protocol conversion circuit of the communication module converts the data format into power line carrier protocol, encrypts it with a hardware encryption chip, and then uploads it to the power grid monitoring center via power line carrier. Downlink commands from the power grid dispatching system send control signals to the main control module through the communication module. The main control module executes the commands and feeds back the execution results to the communication module, which finally transmits them back to the power grid system.

[0011] The sensing module monitors the temperature and electrical parameters of power devices in real time. When the temperature exceeds the threshold or the electrical parameters are abnormal, the sensing module sends a signal to the main control module, triggering the hardware-level protection of the protection module. At the same time, the main control module packages the fault information and uploads it to the power grid monitoring center through the communication module.

[0012] The auxiliary unit module converts the DC or AC voltage to operating voltages such as 3.3V, 5V, and 12V, providing stable power to the main control module, sensing and detection module, communication module, and protection module.

[0013] The main power unit is a DC-side interface module, consisting of a DC filter circuit, a reverse connection protection diode, and a DC circuit breaker. It is used to connect to the DC power output from the photovoltaic array and perform preliminary filtering and protection.

[0014] The protection module includes integrated overvoltage / undervoltage protection circuits, overcurrent protection circuits, and overtemperature protection circuits, which work in conjunction with the main control module to achieve rapid hardware-level protection.

[0015] The carrier communication module can perform protocol identification and adaptation: the system automatically identifies the device protocol type through feature code analysis, handshake probing and other methods, loads the corresponding parser to establish a connection; the protocol library supports online expansion and updates, and the mainstream supported protocols include Modbus RTU commonly used in inverters, RS485 interface, and DL / T645 protocol for smart energy meters, and provides a unified data model mapping.

[0016] The data encryption and authentication functions of the carrier communication module use the national cryptographic algorithm SM4 to encrypt the collected inverter power generation data, operating status and control commands end-to-end.

[0017] The photovoltaic inverter with the integrated carrier communication module of the present invention can achieve the same effect by using an external protocol converter + photovoltaic inverter.

[0018] The technical effects of this invention are as follows: (1) Solve the problem of communication protocol compatibility and stability. By using the protocol adaptation unit of the carrier communication module to build a multi-standard protocol library, automatic protocol matching with the State Grid area acquisition terminal can be achieved without the need to install an additional protocol converter. This simplifies the communication link and reduces the communication transformation cost by 30% to 40%, significantly improving communication reliability.

[0019] (2) To achieve precise real-time control, the intelligent control module of the carrier communication module takes high performance as its core and dynamically adjusts the active / reactive power output according to the changes in grid load to meet the control requirements of the State Grid.

[0020] (3) By using priority queues and the national cryptographic SM4 encryption mechanism, the control commands are transmitted with priority encryption and are not tampered with, which effectively solves the problems of "control lag" and "command failure" of traditional inverters, avoids the circuit breaker tripping caused by reverse overload of the distribution area, and ensures the stable operation of the power grid.

[0021] (4) It has expansion and upgrade capabilities: the intelligent control module has reserved firmware upgrade interface, which can remotely upgrade the algorithm or add new functions through the carrier communication module to adapt to the new requirements of the future smart grid for photovoltaic inverters; the standardized hardware interface supports multiple application scenarios such as energy storage and microgrids, improving equipment reusability and market competitiveness. Attached Figure Description

[0022] Figure 1 A schematic diagram of the structure of the photovoltaic inverter with the integrated carrier communication module created by this invention in the power sector communication; Figure 2 A schematic diagram of the horizontal and vertical management regional framework of the power dispatching department for the photovoltaic inverter with integrated carrier communication module created by the present invention. Detailed Implementation Reference Figure 1 As shown: The low-voltage distribution network system with distributed photovoltaic power generation is constructed with the 10kV busbar outgoing line (serial number 9) stepped down to 380 / 220V (serial number 8) via the transformer (serial number 7). Residential loads draw power directly, and distributed photovoltaic power generation is grid-connected. On the equipment side, power supply control and metering protection are achieved through disconnectors (5), meters (4), and circuit breakers (3). Data acquisition relies on HPLC technology, with equipment data collected to the intelligent terminal (6) in the distribution area via the internal network communication line, and then uploaded to the property management platform and the data collection system via the external network communication line, ultimately connecting to the real-time measurement center. This forms a complete link of "grid power supply - photovoltaic grid connection - equipment management - intelligent data monitoring," ensuring reliable power supply and distributed energy consumption, and realizing intelligent management and efficient operation and maintenance of the distribution network through a layered communication architecture.

[0023] Reference Figure 2As shown, the overall architecture for distributed photovoltaic (PV) management and control is horizontally divided into a production control area and a management information area. The production control area, based on the needs of relevant departments in the power company's distribution technology field, is responsible for the regulation and control of distributed PV systems connected to medium voltage (10kV) and the generation of control commands for distributed PV systems connected to low voltage (380V). The management information area is responsible for the management and control of distributed PV systems at the substation level and the management of low-voltage distributed PV data.

[0024] The main control module collects the electrical parameters and physical quantities of the main power unit through the sensing and detection module, generates a PWM signal to drive it to complete the AC-DC conversion, and the linkage protection module realizes hardware-level protection. The communication module encrypts and converts the operating data uploaded by the main control module, transmits it to the monitoring center via HPLC carrier wave, and simultaneously receives downlink commands, decrypts and parses them and sends them to the main control module. The auxiliary unit provides the appropriate operating voltage for each core component. The four work together to achieve efficient power conversion, safe communication and stable operation.

[0025] The main power unit is primarily a DC-side interface module, which includes a DC filter circuit, reverse connection protection diodes, and a DC circuit breaker. It is used to connect to the DC power output from the photovoltaic array and perform preliminary filtering and protection. The power conversion module consists of power switching devices, drive circuits, high-frequency transformers, and LC filter circuits. It is responsible for inverting the DC power into AC power that conforms to the grid standards. The AC-side interface module includes an AC contactor, grid-connected relay, AC filter circuit (capacitors and inductors), and islanding effect detection circuit. It is used to connect the inverted AC power to the grid and achieve grid-connected protection.

[0026] The main control module of the control and monitoring unit integrates AD sampling circuit and PWM signal generation circuit, and is responsible for the overall operation logic control of the inverter; the sensing and detection module includes voltage sensors (DC side and AC side), current sensors and temperature sensors, which collect key electrical parameters and physical quantities in real time; the protection module includes integrated overvoltage / undervoltage protection circuit, overcurrent protection circuit and overtemperature protection circuit, which work in conjunction with the main control module to achieve hardware-level fast protection.

[0027] The communication module mainly consists of a communication control unit that integrates a hardware encryption chip (such as the national standard SM4 chip) to encrypt transmitted data and ensure communication security. The protocol conversion circuit is responsible for data format conversion and communication logic control.

[0028] The auxiliary unit converts the DC or AC voltage into the operating voltage required by each module.

[0029] The main control module interacts logically with the power unit. The main control module acquires the DC-side voltage / current and AC-side voltage / current in real time through the sensing and detection module (for grid-connected synchronous control), generates PWM signals to drive the power conversion module, and enables the inverter to output AC power that conforms to the grid frequency and voltage standards. At the same time, it monitors the temperature of the power devices, and triggers the protection module to cut off the output when the temperature exceeds the threshold.

[0030] The main control module periodically packages the inverter's operating data (power generation, output power, voltage and current, fault codes, etc.) and sends it to the communication module via serial port; after protocol conversion and encryption, the communication module uploads it to the power grid monitoring center via HPLC power line carrier.

[0031] Downlink commands are instructions received by the communication module from the power grid dispatch system, decrypted, parsed into control signals, and sent to the main control module; the main control module executes the commands and provides feedback on the execution results.

[0032] The vertical system for distributed photovoltaic (PV) management can be decomposed into three parts: the power station side, the terminal side, and the platform side. The power station side includes the distributed PV energy system, which completes the data acquisition and transmission of distributed PV at the power station and responds to control requirements. The terminal side mainly includes 10kV boundary switches and intelligent distribution terminals. The boundary switches are responsible for the data acquisition and transmission of medium-voltage T-connected PV, receiving control commands issued by distribution control zone I, and directing the tripping commands directly by the boundary switches. The control commands are forwarded to the 10kV power station through the FTU. The intelligent distribution terminals are responsible for the data acquisition and aggregation of distributed PV in the distribution area, the autonomous operation of distributed PV in the distribution area, receiving and decomposing dispatch control commands, etc. The platform side consists of the package dispatch system, the distribution control system, and the user acquisition system, which are responsible for the management and control of distributed PV data and the regulation of generated power.

Claims

1. A photovoltaic inverter with an integrated carrier communication module, characterized in that, The main control module collects the electrical parameters and physical quantities of the main power unit through the sensing and detection module, generates a PWM signal to drive it to complete the AC-DC conversion, and the linkage protection module realizes hardware-level protection; the communication module encrypts and converts the operating data uploaded by the main control module, transmits it to the monitoring center via HPLC carrier, and simultaneously receives downlink commands, decrypts and parses them and sends them to the main control module; the auxiliary unit module provides the appropriate operating voltage for each module.

2. The photovoltaic inverter with an integrated carrier communication module according to claim 1, characterized in that, The main control module and the power unit interact logically. The main control module obtains the DC side voltage and current and the AC side voltage and current in real time through the sensing and detection module, generates PWM signals to drive the power conversion module, so that the inverter outputs AC power that conforms to the grid frequency and voltage standards; at the same time, it monitors the temperature of the power devices, and triggers the protection module to cut off the output when the temperature exceeds the threshold.

3. The photovoltaic inverter with an integrated carrier communication module according to claim 1, characterized in that, The main control module periodically collects inverter operating data and sends it to the communication module via serial port. The protocol conversion circuit of the communication module converts the data format into power line carrier protocol, encrypts it with a hardware encryption chip, and then uploads it to the power grid monitoring center via power line carrier. Downlink commands from the power grid dispatching system send control signals to the main control module through the communication module. The main control module executes instructions and feeds back the execution results to the communication module, which in turn transmits them back to the power grid system.

4. The photovoltaic inverter with an integrated carrier communication module according to claim 1, characterized in that, The sensing module monitors the temperature and electrical parameters of power devices in real time. When the temperature exceeds the threshold or the electrical parameters are abnormal, the sensing module sends a signal to the main control module, triggering the hardware-level protection of the protection module. At the same time, the main control module packages the fault information and uploads it to the power grid monitoring center through the communication module.

5. The photovoltaic inverter with an integrated carrier communication module according to claim 1, characterized in that, The auxiliary unit module converts the DC or AC voltage to operating voltages such as 3.3V, 5V, and 12V, providing stable power to the main control module, sensing and detection module, communication module, and protection module.

6. The photovoltaic inverter with an integrated carrier communication module according to claim 1, characterized in that, The main power unit is a DC-side interface module, consisting of a DC filter circuit, a reverse connection protection diode, and a DC circuit breaker. It is used to connect to the DC power output from the photovoltaic array and perform preliminary filtering and protection.

7. The photovoltaic inverter with an integrated carrier communication module according to claim 5, characterized in that, The protection module includes integrated overvoltage / undervoltage protection circuits, overcurrent protection circuits, and overtemperature protection circuits, which work in conjunction with the main control module to achieve rapid hardware-level protection.

8. The photovoltaic inverter with an integrated carrier communication module according to claim 1, characterized in that, The carrier communication module can perform protocol identification and adaptation: the system automatically identifies the device protocol type through feature code analysis, handshake probing and other methods, loads the corresponding parser to establish a connection; the protocol library supports online expansion and updates, and the mainstream supported protocols include Modbus RTU commonly used in inverters, RS485 interface, and DL / T645 protocol for smart energy meters, and provides a unified data model mapping.

9. The photovoltaic inverter with an integrated carrier communication module according to claim 1, characterized in that, The data encryption and authentication functions of the carrier communication module use the national cryptographic algorithm SM4 to encrypt the collected inverter power generation data, operating status and control commands end-to-end.

Images