Photovoltaic string power balancing and optimizing method and system based on wireless communication
By monitoring the output current and voltage of the photovoltaic string in real time, a power distribution map is generated, and the modules are grouped using wireless communication. This solves the power loss problem caused by module mismatch, improves the power generation efficiency and reliability of the photovoltaic string, and reduces hardware and communication costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-04-07
AI Technical Summary
The power loss problem caused by component mismatch in traditional photovoltaic strings is difficult to promote in complex scenarios due to high hardware costs and high communication complexity.
By monitoring the output current and voltage of photovoltaic modules within a string in real time, a power distribution map is generated. Reconfiguration commands are then issued via a wireless communication network to group the modules and form main current and bypass current paths, thus replacing the traditional PLC and reducing hardware and communication complexity.
It effectively overcomes the "weakest link" effect, increases string power generation, reduces operation and maintenance complexity, is suitable for complex scenarios, and enables automatic diagnosis and optimization.
Smart Images
Figure CN121814028A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of photovoltaic power generation, and particularly relates to a photovoltaic string power balancing and optimization method and system based on wireless communication. BACKGROUND
[0002] In a traditional series structure photovoltaic string, the string output current is limited by the smallest current of the photovoltaic components in the string (i.e. the "bottleneck effect"). When some components have reduced power generation capacity due to shadow, stains, aging or failure, the power generation performance of the entire string will be severely impaired. In the prior art, a conventional optimizer performs power optimization at the component level through an MPPT (Maximum Power Point Tracking) module and a DC-DC (Direct Current-Direct Current Converter) module, and uses PLC power carrier communication, but such a scheme has high hardware cost, limited communication capacity and complex wiring, and is difficult to be widely promoted in complex scenarios such as distributed roof and mountain power station. SUMMARY
[0003] Therefore, it is necessary to provide a photovoltaic string power balancing and optimization method and system based on wireless communication to solve the technical problem of power loss caused by shadow and component mismatch, so as to maximize the overall output power of the string while reducing hardware cost and communication complexity.
[0004] A photovoltaic string power balancing and optimization method based on wireless communication, comprising the following steps: monitoring the output current and output voltage of each photovoltaic component in the string in real time, and calculating the real-time power according to the output current and output voltage to generate a power distribution map; determining whether the power difference between each photovoltaic component exceeds a preset difference threshold according to the power distribution map; when the power difference exceeds the preset difference threshold, issuing a string reconstruction instruction through a wireless communication network; grouping photovoltaic components according to the string reconstruction instruction to form a main current path and a side current path in series respectively.
[0005] In one embodiment, the wireless communication network uses a WIoTa Internet of Things communication protocol.
[0006] In one embodiment, determining whether the power difference between each photovoltaic component exceeds a preset difference threshold according to the power distribution map comprises: calculating the power difference between each photovoltaic component in the string according to the power distribution map; obtaining a preset difference threshold and comparing the relationship between the power difference and the preset difference threshold; and maintaining the current circuit structure of the string when the power difference is less than the preset difference threshold.
[0007] In one of the embodiments, the photovoltaic module grouping according to the group string reconstruction instruction to form the main current path and the side current path in series respectively comprises: detecting the output power of each photovoltaic module in the group string based on the group string reconstruction instruction; obtaining the stable power of the photovoltaic module, calculating the difference value between the output power of all photovoltaic modules and the stable power, and judging the relationship between the difference value and the grouping threshold; when the difference value is greater than or equal to the grouping threshold, the photovoltaic module is grouped into a high-power group to form the main current path in series; when the difference value is less than the grouping threshold, the photovoltaic module is grouped into a low-power group to form the side current path in series.
[0008] In one of the embodiments, it further comprises: continuously detecting the output power of the photovoltaic module in the low-power group; when the output power of the photovoltaic module is detected to recover to the preset power, the instruction is triggered to add the corresponding photovoltaic module to the high-power group for series power generation.
[0009] A photovoltaic group string power balancing and optimization system based on wireless communication is used to realize the photovoltaic group string power balancing and optimization method based on wireless communication as described above, comprising: a plurality of photovoltaic intelligent control terminals, a WIoTa wireless intelligent gateway and a system control end; the plurality of photovoltaic intelligent control terminals are connected with a plurality of photovoltaic modules, used to monitor the output current and output voltage of each photovoltaic module in the group string in real time, and to group the photovoltaic modules under the group string reconstruction instruction to form the main current path and the side current path in series respectively; the WIoTa wireless intelligent gateway is used to transmit data between the photovoltaic intelligent control terminal and the system control end; the system control end is used to calculate the real-time power according to the output current and output voltage, to generate a power distribution diagram, to judge whether the power difference between each photovoltaic module exceeds the preset difference threshold according to the power distribution diagram, and to issue the group string reconstruction instruction through the WIoTa wireless intelligent gateway when the power difference exceeds the preset difference threshold.
[0010] Compared with the prior art, the advantages and beneficial effects of the present application are that: by monitoring the output current and output voltage of each photovoltaic module in the string in real time, the real-time power is calculated, the power distribution map is generated, and whether the power difference between each photovoltaic module exceeds the preset difference threshold is judged according to the power distribution map. When the power difference exceeds the preset difference threshold, the string reconstruction instruction is issued through the wireless communication network, replacing the traditional PLC, improving the terminal access capacity, reducing the wiring cost, reducing the hardware cost and communication complexity, facilitating the widespread promotion in various complex scenes, grouping photovoltaic modules according to the string reconstruction instruction, and respectively forming a main current path and a side current path in series, thereby effectively overcoming the barrel effect, improving the string power generation capacity in the shadow, uneven stains, component aging or failure scene, even if part of the component fails, it can also ensure efficient power generation of the remaining components, and can realize automatic diagnosis and optimization of power mismatch without manual intervention, reducing the operation and maintenance complexity. BRIEF DESCRIPTION OF DRAWINGS
[0011] Figure 1 It is a flowchart of a photovoltaic string power balancing and optimization method based on wireless communication in one embodiment.
[0012] Figure 2 It is a schematic diagram of the string current path after the component reconstruction in one embodiment.
[0013] Figure 3 It is a structural schematic diagram of a photovoltaic string power balancing and optimization system based on wireless communication in one embodiment. DETAILED DESCRIPTION
[0014] Before the specific embodiment of the present application is described, the overall concept of the present application is described as follows:
[0015] The present application is mainly developed based on the photovoltaic string regulation process. The current series structure photovoltaic string is prone to power mismatch problems, and the hardware cost is high, the wiring is complex, and it is difficult to be widely promoted.
[0016] Therefore, this invention proposes a photovoltaic string power balancing and optimization method based on wireless communication. By real-time monitoring of the output current and output voltage of each photovoltaic module in the string, the real-time power is calculated and a power distribution map is generated. Based on the power distribution map, it is determined whether the power difference between photovoltaic modules exceeds a preset difference threshold. When the power difference exceeds the preset difference threshold, a string reconstruction command is issued through the wireless communication network, replacing the traditional PLC. This improves the terminal access capacity, reduces wiring costs, lowers hardware costs and communication complexity, and facilitates widespread application in various complex scenarios. According to the string reconstruction command, photovoltaic modules are grouped and connected in series to form the main current path and the bypass current path, thereby effectively overcoming the bottleneck effect. In scenarios with shadows, uneven stains, module aging or failure, the string power generation is improved. Even if some modules fail, the high-efficiency power generation of the remaining modules can be ensured. It can also realize automatic diagnosis and optimization of power mismatch without manual intervention, reducing the complexity of operation and maintenance.
[0017] Having introduced the overall concept of the present invention, to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.
[0018] In one embodiment, such as Figure 1 As shown, a method for power equalization and optimization of photovoltaic strings based on wireless communication is provided, including the following steps:
[0019] Step S110: Monitor the output current and output voltage of each photovoltaic module in the string in real time, calculate the real-time power based on the output current and output voltage, and generate a power distribution map.
[0020] Specifically, a photovoltaic string connects multiple photovoltaic modules. The output current and output voltage of all photovoltaic modules are monitored in real time, the corresponding real-time power is calculated, and a power distribution map of the photovoltaic modules is generated. This allows for the determination of the power differences among different photovoltaic modules within a photovoltaic string based on the power distribution map.
[0021] Step S120: Based on the power distribution diagram, determine whether the power difference between each photovoltaic module exceeds a preset difference threshold.
[0022] Specifically, after generating the power distribution map, the power distribution map is analyzed by an optimization algorithm to determine whether the power difference between each photovoltaic string exceeds a preset difference threshold. The preset difference threshold can be set according to the actual situation, such as 25%, to meet the actual usage requirements and ensure the adaptability of subsequent photovoltaic module grouping.
[0023] Step S120 includes: calculating the power difference between photovoltaic modules in the string based on the power distribution diagram; obtaining a preset difference threshold and comparing the relationship between the power difference and the preset difference threshold; and maintaining the circuit structure of the current string when the power differences are all less than the preset difference threshold.
[0024] Specifically, after obtaining the power distribution map, the power difference between each photovoltaic module in the string is calculated based on the power distribution map to obtain the power difference between all photovoltaic modules. A preset difference threshold for the power difference is obtained, and the relationship between all power differences and the preset difference threshold is compared. If all power differences are less than the preset difference threshold, it means that the power of each photovoltaic module in the current string is relatively stable and matched. Then the circuit structure of the current string is maintained, and no circuit structure adjustment is required.
[0025] Step S130: When the power difference exceeds a preset difference threshold, a string reconstruction command is sent through the wireless communication network.
[0026] Specifically, when a power difference between photovoltaic modules within a string is detected to exceed a preset difference threshold, indicating a power mismatch issue, a string reconfiguration command can be issued via the wireless communication network to reconfigure the string and adjust the string current path in a timely manner. Communication via wireless IoT replaces the traditional PLC, increasing terminal access capacity, reducing wiring costs, and eliminating the need for MPPT and DC-DC modules, requiring only data acquisition and bypass functions, thus reducing module-level optimization costs.
[0027] The wireless communication network adopts the WIoTa Internet of Things communication protocol.
[0028] Specifically, WIoTa IoT communication has advantages such as wide coverage, low power consumption, high sensitivity and throughput, low cost and high integration, flexible networking methods, and high stability. It can achieve efficient communication in the process of photovoltaic string power balancing and optimization, and meet the needs of real-time optimization.
[0029] Step S140: The photovoltaic modules are grouped according to the string reconfiguration instruction and connected in series to form the main current path and the bypass current path.
[0030] Specifically, according to the string reconfiguration command, the photovoltaic modules within the string are regrouped based on their power levels. These regrouped modules are then connected in series to form a main current path and a bypass current path. This allows for timely string reconfiguration in situations such as shading, uneven soiling, module aging, or failure, thereby increasing string power generation. By assigning photovoltaic modules with similar performance to the same current path, string reconfiguration ensures that current primarily flows through the high-power modules, bypassing the low-power modules. This is equivalent to forming a shorter, higher-current new string. Figure 2As shown, this ensures the consistency of photovoltaic modules within the same current path, thereby improving the power generation efficiency and reliability of the photovoltaic system.
[0031] Step S140 includes: based on the string reconfiguration instruction, detecting the output power of each photovoltaic module in the string; obtaining the stable power of the photovoltaic module, calculating the difference between the output power and the stable power of all photovoltaic modules, and determining the relationship between the difference and the grouping threshold; when the difference is greater than or equal to the grouping threshold, grouping the photovoltaic modules into the high-power group and connecting them in series to form the main current path; when the difference is less than the grouping threshold, grouping the photovoltaic modules into the low-power group and connecting them in series to form the bypass current path.
[0032] Specifically, after determining the power mismatch of photovoltaic modules within a string and receiving a string reconfiguration command, the system detects the output power of each photovoltaic module within the string and obtains the stable power of the photovoltaic modules before the power mismatch, such as the average output power of all photovoltaic modules, or a stable value set according to actual conditions, such as 485W. It then calculates the difference between the output power and the stable power of all photovoltaic modules. A grouping threshold is set, for example, 10. When the difference is greater than or equal to the grouping threshold, the corresponding photovoltaic module is assigned to the high-power group, and all photovoltaic modules in the high-power group are connected in series to form the main current path, maintaining a direct current flow for photovoltaic power generation. When the difference is less than the grouping threshold, the corresponding photovoltaic module is assigned to the low-power group, and all photovoltaic modules in the low-power group are connected in series to form a bypass current path, isolating them from the main current path. This effectively overcomes the "weakest link" effect, improving module power generation in scenarios with shading, uneven staining, module aging, or failure. Even if some modules fail, the bypass ensures efficient power generation of the remaining modules.
[0033] In one embodiment, the method further includes: continuously detecting the output power of the photovoltaic modules in the low-power group; and triggering an instruction to add the corresponding photovoltaic modules to the high-power group for series power generation when the output power of the photovoltaic modules is detected to recover to the preset power.
[0034] Specifically, the output power of each photovoltaic module in the low-power group is continuously monitored to obtain a preset power. The preset power can be calculated based on the output power of the photovoltaic module and a preset difference threshold. For example, if the output power of the photovoltaic module is 500W and the preset difference threshold is 25%, then the preset power is 375W. When the output power of the photovoltaic module is detected to have recovered to the preset power, a command is triggered to add the corresponding photovoltaic module to the high-power group for series power generation. The photovoltaic modules in the high-power group and the low-power group are reconnected in series to respond to changes in sunlight and achieve dynamic adaptive optimization.
[0035] In this embodiment, the real-time power is calculated by monitoring the output current and output voltage of each photovoltaic module in the string, generating a power distribution map. Based on the power distribution map, it is determined whether the power difference between each photovoltaic module exceeds a preset difference threshold. When the power difference exceeds the preset difference threshold, a string reconfiguration command is issued through the wireless communication network, replacing the traditional PLC. This improves the terminal access capacity, reduces wiring costs, lowers hardware costs and communication complexity, and facilitates widespread application in various complex scenarios. The photovoltaic modules are grouped according to the string reconfiguration command and connected in series to form the main current path and the bypass current path, thereby effectively overcoming the bottleneck effect. In scenarios with shadows, uneven stains, module aging, or failure, the string power generation is improved. Even if some modules fail, the high-efficiency power generation of the remaining modules can be ensured. Furthermore, automatic diagnosis and optimization of power mismatch can be achieved without manual intervention, reducing the complexity of operation and maintenance.
[0036] like Figure 3 As shown, a photovoltaic string power balancing and optimization system 20 based on wireless communication is provided to implement the photovoltaic string power balancing and optimization method based on wireless communication as described above. The system includes: multiple photovoltaic intelligent control terminals 10, a WIoTa wireless intelligent gateway 20, and a system control terminal 30. The multiple photovoltaic intelligent control terminals 10 are connected to several photovoltaic modules 11, used to monitor the output current and output voltage of each photovoltaic module 11 in the string in real time, and to group the photovoltaic modules 11 into groups under string reconstruction commands, forming a main current path and a bypass current path respectively. The WIoTa wireless intelligent gateway 20 is used for data transmission between the photovoltaic intelligent control terminals 10 and the system control terminal 30. The system control terminal 30 is used to calculate the real-time power based on the output current and output voltage, generate a power distribution map, and determine whether the power difference between each photovoltaic module exceeds a preset difference threshold based on the power distribution map. When the power difference exceeds the preset difference threshold, a string reconstruction command is issued through the WIoTa wireless intelligent gateway 20.
[0037] In one embodiment, the system control terminal 30 is further configured to: calculate the power difference between each photovoltaic module in the string according to the power distribution diagram; obtain a preset difference threshold and compare the relationship between the power difference and the preset difference threshold; and maintain the circuit structure of the current string when the power differences are all less than the preset difference threshold.
[0038] In one embodiment, the system control terminal 30 is further configured to: detect the output power of each photovoltaic module in the string based on the string reconfiguration instruction; obtain the stable power of the photovoltaic module, calculate the difference between the output power and the stable power of all photovoltaic modules, and determine the relationship between the difference value and the grouping threshold; when the difference value is greater than or equal to the grouping threshold, group the photovoltaic modules into the high-power group and connect them in series to form the main current path; when the difference value is less than the grouping threshold, group the photovoltaic modules into the low-power group and connect them in series to form the bypass current path.
[0039] In one embodiment, the system control terminal 30 is further configured to: continuously detect the output power of the photovoltaic modules in the low-power group; and when the output power of the photovoltaic modules is detected to recover to the preset power, trigger an instruction to add the corresponding photovoltaic modules to the high-power group for series power generation.
[0040] In one embodiment, taking a typical rooftop photovoltaic system as an example, the string consists of 10 photovoltaic modules connected in series, each module is connected to a photovoltaic smart control terminal, the system control terminal is a cloud platform, communication is carried out through the WIoTa wireless network, there are tall pole-shaped obstacles near the photovoltaic array, which cause moving shadows to the photovoltaic as the sun moves.
[0041] Initially, the string output power is 5.0kW under uniform illumination.
[0042] Shadowing occurred at 10:00 AM. The shadow of the high pole obstacle moved, causing the No. 3 and No. 4 components to be covered by shadow. Their output power dropped from 500W to 350W and 300W respectively, with a power difference of 30% and 40% (exceeding the threshold of 25%). The string power was reduced from the minimum current control of the No. 4 component to 3.0kW.
[0043] System response: The control terminal identifies mismatches through the power distribution map, and the algorithm divides the components into high-power groups (1, 2, 5, 6, 7, 8, 9, 10) and low-power groups (3, 4).
[0044] The WIoTa network sends a "forced bypass" command to low-power group terminals and an "optimized mode" command to high-power group terminals.
[0045] Reconfiguration result: After the current path is reconfigured, the string is equivalent to 8 high-power components connected in series, and the output power is increased to 4.0kW (33.3% higher than the 3.0kW before reconfiguration).
[0046] The bypass component remains under monitoring, but it does not participate in power generation.
[0047] Dynamic recovery: At 10:30 AM, the shadows were removed, and the power of components 3 and 4 was restored to 500W.
[0048] The control unit detected the change and sent a command to remove it from the bypass and rejoin the string, restoring the string power to 5.0kW.
[0049] In summary, the photovoltaic string power balancing and optimization achieved using the method described in this application yields the following results:
[0050] First, power generation increased. During the shaded period, string power generation increased from 3.0 kWh before reconfiguration to 4.0 kWh, representing a 33.3% improvement in efficiency.
[0051] Second, communication latency is reduced. The average latency for WIoTa network command issuance is less than 250ms, meeting the requirements for real-time optimization.
[0052] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.
[0053] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. Optionally, they can be implemented using computer-executable program code, thereby storing them in a computer storage medium (ROM / RAM, magnetic disk, optical disk) for execution by the computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Therefore, the present invention is not limited to any particular hardware and software combination.
[0054] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered within the scope of protection of the present invention.
Claims
1. A method for power equalization and optimization of photovoltaic strings based on wireless communication, characterized in that, Includes the following steps: The output current and output voltage of each photovoltaic module in the string are monitored in real time, and the real-time power is calculated based on the output current and output voltage to generate a power distribution map; Based on the power distribution diagram, determine whether the power difference between each photovoltaic module exceeds a preset difference threshold; When the power difference exceeds the preset difference threshold, a string reconstruction command is sent through the wireless communication network; The photovoltaic modules are grouped according to the string reconfiguration instruction and connected in series to form the main current path and the bypass current path.
2. The photovoltaic string power equalization and optimization method based on wireless communication according to claim 1, characterized in that, The wireless communication network adopts the WIoTa Internet of Things communication protocol.
3. The photovoltaic string power equalization and optimization method based on wireless communication according to claim 1, characterized in that, The step of determining whether the power difference between each photovoltaic module exceeds a preset difference threshold based on the power distribution map includes: Based on the power distribution diagram, the power difference between each photovoltaic module in the string is calculated; Obtain a preset difference threshold and compare the relationship between the power difference and the preset difference threshold; When the power differences are all less than a preset difference threshold, the circuit structure of the current string is maintained.
4. The photovoltaic string power equalization and optimization method based on wireless communication according to claim 1, characterized in that, The step of grouping photovoltaic modules according to the string reconfiguration instruction, and connecting them in series to form a main current path and a bypass current path, includes: Based on the string reconstruction instruction, the output power of each photovoltaic module in the string is detected; Obtain the stable power of the photovoltaic modules, calculate the difference between the output power of all photovoltaic modules and the stable power, and determine the relationship between the difference and the grouping threshold. When the difference value is greater than or equal to the grouping threshold, the photovoltaic modules are grouped into the high-power group and connected in series to form the main current path; When the difference value is less than the grouping threshold, the photovoltaic modules are grouped into the low-power group and connected in series to form a bypass current path.
5. The photovoltaic string power equalization and optimization method based on wireless communication according to claim 4, characterized in that, Also includes: Continuously monitor the output power of the photovoltaic modules in the low-power group; When the output power of the photovoltaic module is detected to have recovered to the preset power, a command is triggered to add the corresponding photovoltaic module to the high-power group for series power generation.
6. A photovoltaic string power equalization and optimization system based on wireless communication, characterized in that, A method for implementing a photovoltaic string power equalization and optimization method based on wireless communication as described in any one of claims 1-5 includes: Multiple photovoltaic intelligent control terminals, WIoTa wireless intelligent gateways, and system control terminals; The multiple photovoltaic intelligent control terminals are connected to several photovoltaic modules, which are used to monitor the output current and output voltage of each photovoltaic module in the string in real time, and to group the photovoltaic modules under the string reconstruction command, and connect them in series to form the main current path and the side current path respectively. The WIoTa wireless smart gateway is used for data transmission between the photovoltaic smart control terminal and the system control terminal; The system control terminal is used to calculate the real-time power based on the output current and output voltage, generate a power distribution map, determine whether the power difference between each photovoltaic module exceeds a preset difference threshold based on the power distribution map, and issue a string reconstruction command through the WIoTa wireless smart gateway when the power difference exceeds the preset difference threshold.