Photovoltaic module level power generation system

Abstract

The invention discloses a photovoltaic module level power generation system. The system comprises a plurality of photovoltaic strings, a string stage power optimizer, a convergence module and an inversion module, the photovoltaic group string comprises at least two component-level power optimizers; wherein the input end of each component-level power optimizer is coupled with a photovoltaic component; the output ends of the component-level power optimizers are connected in series and then output; part of the photovoltaic group strings are coupled with the inversion module through the group string stage power optimizers which are arranged in one-to-one correspondence with the photovoltaic group strings; and part of the photovoltaic group strings are coupled with the inversion module through the common convergence module. The photovoltaic module-level power generation system can give consideration to the power generation efficiency, the cost and the installation flexibility.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a photovoltaic module-level power generation system. Background Technology

[0002] With the continuous development of photovoltaic technology, photovoltaic power generation systems are being used more and more widely. For example, photovoltaic power generation systems can be deployed in places with abundant solar resources, such as deserts, mountains, water surfaces, and rooftops. In existing technologies, photovoltaic power generation systems can be roughly divided into centralized inverter power generation (single-stage inverter), string inverter power generation, module-level inverter power generation, and module-level power optimizer + inverter power generation, etc.

[0003] Among them, the module-level power optimizer + inverter power generation method has the advantages of high power generation and good safety, and is gradually becoming a trend in distributed rooftop photovoltaic power generation systems. However, in the current technology, when using the module-level power optimizer + inverter method for photovoltaic power generation, if the power generation efficiency and cost are to be guaranteed, the installation flexibility must be sacrificed; if the installation flexibility is to be guaranteed, the power generation efficiency will be reduced and the cost will be increased. Summary of the Invention

[0004] This invention provides a photovoltaic module-level power generation system that balances power generation efficiency, cost, and installation flexibility.

[0005] This photovoltaic module-level power generation system includes:

[0006] Multiple photovoltaic strings, each photovoltaic string including at least two module-level power optimizers; wherein the input terminal of each module-level power optimizer is coupled to a photovoltaic module; and the output terminals of each module-level power optimizer are connected in series for output.

[0007] The system comprises a string-level power optimizer, a combiner module, and an inverter module; wherein, some of the photovoltaic strings are coupled to the inverter module through the string-level power optimizer, which is configured one-to-one with each other; and some photovoltaic strings are coupled to the inverter module through the common combiner module.

[0008] Optionally, the photovoltaic string coupled to the string-level power optimizer is a first photovoltaic string, and the photovoltaic string coupled to the combiner module is a second photovoltaic string;

[0009] The number of the first photovoltaic strings is less than the number of the second photovoltaic strings.

[0010] Optionally, the first photovoltaic string is a single string; the second photovoltaic string is multiple strings.

[0011] Optionally, the photovoltaic string coupled to the string-level power optimizer is a first photovoltaic string, and the photovoltaic string coupled to the combiner module is a second photovoltaic string;

[0012] Wherein, the length of the first photovoltaic string is less than the length of the second photovoltaic string; and the difference in length between each second photovoltaic string is less than a set threshold.

[0013] Optionally, the photovoltaic string coupled to the string-level power optimizer is a first photovoltaic string, and the photovoltaic string coupled to the combiner module is a second photovoltaic string;

[0014] The illumination time of the first photovoltaic string is less than that of the second photovoltaic string.

[0015] Optionally, the photovoltaic string coupled to the combiner module is a second photovoltaic string;

[0016] The second photovoltaic string also includes a protection unit, which is connected in series between the output terminal of the second photovoltaic string and the combiner module.

[0017] Optionally, the protection unit includes at least one of the following: a reverse protection diode, a fuse, and a protection switch.

[0018] Optionally, the correspondence between the module-level power optimizer and the photovoltaic module includes at least one of the following:

[0019] The component-level power optimizer is coupled to one of the photovoltaic modules;

[0020] The component-level power optimizer is coupled to at least two of the photovoltaic modules.

[0021] Optionally, the connection bus of the string power optimizer, the combiner module and the inverter module is a DC bus;

[0022] The photovoltaic module-level power generation system further includes: a DC load and / or a DC power supply; wherein the DC load is coupled to the DC bus, and the DC power supply is coupled to the DC bus.

[0023] Optionally, the DC load includes at least one of an energy storage battery and a charging pile.

[0024] The photovoltaic module-level power generation system provided in this invention, by setting two different connection methods for photovoltaic strings, allows for flexible setting of the number of photovoltaic modules while ensuring the power generation efficiency of the photovoltaic strings and controlling the required costs. This design enables the photovoltaic module-level power generation system to be optimized according to the needs of actual application scenarios, allowing users to flexibly adjust according to illumination conditions and module performance, thereby maximizing power generation efficiency and improving overall economic benefits.

[0025] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a photovoltaic module-level power generation system provided in an embodiment of the present invention;

[0028] Figure 2 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention. Detailed Implementation

[0034] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0035] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0036] Figure 1 This is a schematic diagram of a photovoltaic module-level power generation system provided in an embodiment of the present invention. This embodiment is applicable to rooftop photovoltaic systems. Figure 1 As shown, the photovoltaic module-level power generation system includes:

[0037] Multiple photovoltaic strings 10, each photovoltaic string 10 including at least two module-level power optimizers ( Figure 1 (not shown in the image); wherein, the input terminal of each component-level power optimizer is coupled to the photovoltaic module; the output terminals of each component-level power optimizer are connected in series and then output.

[0038] The system includes a string-level power optimizer 20, a combiner module 30, and an inverter module 40. Some photovoltaic strings 10 are coupled to the inverter module 40 through the string-level power optimizer 20, which is configured to correspond to each other. Other photovoltaic strings 10 are coupled to the inverter module 40 through the shared combiner module 30.

[0039] In this context, a module-level power optimizer refers to a device used to individually optimize the output of photovoltaic modules. It ensures that each module operates under optimal conditions by adjusting its output in real time. For example, a module-level power optimizer may include a DC / DC converter.

[0040] The photovoltaic string 10 includes at least two coupled photovoltaic modules and a module-level power optimizer for converting solar energy into electrical energy. The configuration of multiple photovoltaic modules and module-level optimizers ensures that if one photovoltaic module or module-level optimizer fails, the other photovoltaic modules can still operate normally, improving the overall reliability of the system.

[0041] The string-level power optimizer 20 is responsible for optimizing the power output of the entire photovoltaic string 10. For example, the string-level power optimizer 20 may include a DC / DC converter; obviously, the power output of the string-level power optimizer 20 is greater than that of the module-level power optimizer. The combiner module 30 refers to a device that combines the output currents of multiple photovoltaic strings 10 together, and outputs the combined large current to the inverter module 40. The inverter module 40 refers to a module that converts direct current (DC) to alternating current (AC), converting the DC power in the photovoltaic system into AC power for supply to the grid or AC users.

[0042] In this embodiment of the invention, some photovoltaic strings 10 are coupled to the inverter module 40 via their corresponding string-level power optimizers 20. Such photovoltaic strings 10 are referred to as first photovoltaic strings 11. In this connection method, since the string-level power optimizers 20 can transform the output voltage of the first photovoltaic strings 11 to match the input voltage of the inverter module 40, the length of each first photovoltaic string 11 (i.e., the number of coupled photovoltaic modules and module-level power optimizers included) can be set according to requirements, making installation more flexible. Some photovoltaic strings 10 are coupled to the inverter module 40 via a combiner module 30. Such photovoltaic strings 10 are referred to as second photovoltaic strings 12. In this connection method, since the outputs of each second photovoltaic string 12 are connected in parallel, their output voltages cannot differ too much, and the output voltage of the second photovoltaic strings 12 needs to match the input voltage of the inverter module 40. Therefore, the length of each second photovoltaic string 12 is limited to a small range. However, this connection method has high power generation efficiency and relatively low cost.

[0043] The photovoltaic module-level power generation system provided in this embodiment of the invention, by setting two different connection methods for the photovoltaic strings 10, can flexibly set the number of photovoltaic modules, ensure the power generation efficiency of the photovoltaic strings 10, and control the required costs. This design allows the photovoltaic module-level power generation system to be optimized according to the needs of actual application scenarios, allowing users to flexibly adjust according to illumination conditions and module performance, thereby maximizing power generation efficiency and improving overall economic benefits.

[0044] Figure 2 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention. Figure 2As shown, the photovoltaic string 10 includes at least two module-level power optimizers 101; wherein, the input terminal of each module-level power optimizer 101 is coupled to the photovoltaic module 102; and the output terminals of each module-level power optimizer 101 are connected in series and output.

[0045] See also Figure 2 Based on the above embodiments, optionally, in the photovoltaic module-level power generation system, the photovoltaic string coupled to the string-level power optimizer 20 is a first photovoltaic string 11, and the photovoltaic string coupled to the combiner module 30 is a second photovoltaic string 12. The number of first photovoltaic strings 11 is less than the number of second photovoltaic strings 12. For example, the number of first photovoltaic strings 11 is one string; the number of second photovoltaic strings 12 is multiple strings.

[0046] The installation method of the first photovoltaic string 11 is more flexible, and the number of photovoltaic modules can be set according to the application scenario and specific needs. However, compared with the second photovoltaic string 12, it adds the use of a string-level power optimizer 20, which reduces the power generation efficiency of the photovoltaic module-level power generation system and increases the cost. Therefore, in practical applications, the number of first photovoltaic strings 11 is less than the number of second photovoltaic strings 12. That is, the more numerous second photovoltaic strings 12 are used as the main power generation device, and the fewer numerous first photovoltaic strings 11 are used as a supplement. This can be flexibly adjusted according to demand.

[0047] For example, for the second photovoltaic string 12, its DC output voltage must be at least 680V to meet the DC input voltage requirements of the inverter module 40. This requires a photovoltaic string to contain at least 18 and a maximum of 20 photovoltaic modules 102, with 18 being the optimal number. Assume a roof can accommodate 50 photovoltaic modules 102. If only the second photovoltaic string 12 is used, the roof can only accommodate a maximum of 40 photovoltaic modules 102. Specifically, each second photovoltaic string 12 could contain 20 photovoltaic modules 102, for a total of two photovoltaic strings 12. This arrangement leaves 10 photovoltaic modules 102 unused space on the roof, resulting in wasted space. In this embodiment, a combination of one first photovoltaic string 11 and two second photovoltaic strings 12 can be used. The first photovoltaic string 11 contains 12 photovoltaic modules 102, and each second photovoltaic string 12 contains 19 photovoltaic modules 102.

[0048] The photovoltaic module-level power generation system provided in this embodiment of the invention can set the number of the first photovoltaic string 11 and the second photovoltaic string 12 according to actual needs. This design not only ensures the power generation efficiency of the system under different environmental conditions, but also effectively reduces the overall cost, improves the flexibility and scalability of the power generation system, and provides users with a more efficient and economical photovoltaic power generation solution.

[0049] See also Figure 2 Based on the above embodiments, optionally, the length of the first photovoltaic string 11 is less than the length of the second photovoltaic string 12; the difference in length between each second photovoltaic string 12 is less than a set threshold. The set threshold refers to a pre-defined range of lengths for the second photovoltaic strings 12.

[0050] Specifically, in the actual installation of photovoltaic module-level power generation systems, a shorter first photovoltaic string 11 can better adapt to limited space, ensuring that the power generation system operates normally without interfering with other equipment or structures; at the same time, it reduces the complexity of connections between modules, facilitating subsequent maintenance and troubleshooting. The length of each second photovoltaic string 12 should be controlled within a reasonable range, which helps maintain a relatively consistent output voltage of each photovoltaic string, which is beneficial to the normal operation of the module-level power generation system.

[0051] As mentioned earlier, the use of the second photovoltaic string 12 can improve power generation efficiency and reduce costs. Therefore, in practical applications, the number of second photovoltaic strings 12 can be maximized. However, the length setting of the second photovoltaic string 12 lacks flexibility. For example, on a roof with limited space, the number of photovoltaic modules 102 that can be installed is limited. To maximize the use of roof space, users require that the photovoltaic modules 102 can cover the entire roof. However, the length setting of the second photovoltaic string 12 has high requirements, and there are cases where the quantity requirement cannot be met. If the first photovoltaic string 11 is used as a supplementary solution, its length only needs to meet the quantity requirements of the photovoltaic module-level power generation system. This setting can improve the flexibility of photovoltaic module 102 installation while maximizing power generation efficiency and reducing costs.

[0052] Figure 3 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention. Figure 3 As shown, based on the above embodiment, optionally, the illumination time of the first photovoltaic string 11 is less than the illumination time of the second photovoltaic string 12.

[0053] Specifically, in practical applications, the photovoltaic string 10 is significantly affected by the surrounding environment. For example, there may be photovoltaic strings 10 of equal length but with different periods of sunlight exposure, resulting in significant differences in the output voltage of each string 10 and affecting the safety and stability of the photovoltaic module-level power generation system. For instance, in areas with many trees or buildings, their shadows can affect the sunlight exposure time of the photovoltaic string 10.

[0054] For example, the second photovoltaic string 12 is configured in an area with better sunlight conditions to maximize overall power generation. These areas typically have good sunlight conditions, ensuring that each photovoltaic module 102 operates at its optimal state, thereby improving the system's energy efficiency and output. The first photovoltaic string 11 is configured in areas with more shade, such as under the shade of buildings or next to trees. Although these locations have shorter sunshine hours and lower output voltage, they can still generate a certain amount of power through proper configuration.

[0055] The photovoltaic module-level power generation system provided in this embodiment of the invention can reduce output voltage imbalance caused by shading by adjusting the string length and layout. Photovoltaic strings 10 are respectively configured as first photovoltaic strings 11 and second photovoltaic strings 12 for different illumination times. Therefore, this embodiment of the invention can be optimized according to specific installation environments, making the photovoltaic module-level power generation system more flexible and adaptable to various application scenarios. This enables the photovoltaic module-level power generation system to maintain efficient operation under changing environmental conditions, providing users with a continuous and stable power supply while reducing environmental impact.

[0056] Figure 4 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention. Figure 4 As shown, based on the above embodiment, optionally, the second photovoltaic string 12 further includes a protection unit 15, which is connected in series between the output terminal of the second photovoltaic string 12 and the combiner module 30.

[0057] The protection unit 15 refers to a device used to protect the photovoltaic string 10, which may include functions such as overvoltage protection, overcurrent protection, reverse current protection, and short-circuit protection, ensuring the safe operation of the system under abnormal conditions. Overvoltage protection can automatically cut off the current when the voltage exceeds a safe threshold, preventing equipment damage due to excessive voltage. Overcurrent protection can quickly disconnect the circuit when the current exceeds a set range, avoiding the risk of fire caused by overload.

[0058] For example, the protection unit 15 may be a reverse protection diode (such as...) Figure 5 (as shown), fuses or protective switches, etc.

[0059] A reverse-current protection diode is a diode that prevents current from flowing in the reverse direction. In a photovoltaic (PV) power generation system, its main function is to prevent reverse current from flowing from the PV module to the outside under conditions of no sunlight (e.g., at night). If this reverse current is not prevented, it may cause the module to overheat, be damaged, or affect system performance. The installation of a reverse-current protection diode can protect the integrity of the PV module and related equipment, ensuring the long-term stable operation of the system. For example, a reverse-current protection diode can be a Schottky diode.

[0060] A fuse is a device that breaks a circuit by melting an internal metal wire or strip, thereby protecting other components in a system from damage. It can prevent overloads or short circuits in photovoltaic systems. A protective switch is an electrical switch used to manually or automatically disconnect a circuit to protect equipment from overloads, short circuits, or other abnormal conditions.

[0061] In this embodiment of the invention, by setting up protection units 15 such as anti-reverse diodes, fuses and protection switches, the safety and reliability of the photovoltaic module-level power generation system can be effectively improved, ensuring its long-term stable operation.

[0062] It should be noted that in the above embodiments, the exemplary correspondence between the module-level power optimizer and the photovoltaic module is that the module-level power optimizer is coupled to one photovoltaic module, which is not intended to limit the present invention. In other embodiments, the correspondence between the module-level power optimizer and the photovoltaic module can also be set so that the module-level power optimizer is coupled to at least two photovoltaic modules, which can be set as needed in practical applications.

[0063] When a module-level power optimizer is coupled to a photovoltaic (PV) module, each module-level power optimizer is specifically connected to and optimizes the output of that PV module. This ensures that each PV module can maximize its power generation capacity under different lighting conditions. If a PV module malfunctions, only the power optimizer of that module is affected, while other PV modules continue to operate normally, ensuring high reliability.

[0064] When a module-level power optimizer is coupled to at least two photovoltaic modules, one module-level power optimizer can be connected to two or more photovoltaic modules, which can reduce the number of power optimizers required, thereby reducing the overall cost of the system; and it is suitable for situations with limited space, as multiple modules can be optimized in the same location, thereby improving space utilization.

[0065] The photovoltaic module-level power generation system provided in this invention allows for flexible selection of coupling methods based on illumination conditions, space constraints, and cost budgets by flexibly setting the number of module-level power optimizers coupled to photovoltaic modules. In environments with uneven illumination, a one-to-one coupling method ensures independent optimization for each module, maximizing power generation efficiency. Conversely, in situations with limited space or tight budgets, coupling multiple modules to a single power optimizer reduces system complexity and cost. This photovoltaic module-level power generation system not only improves overall power generation efficiency but also enhances system adaptability and reliability, meeting the needs of different users and application scenarios.

[0066] Figure 6 This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention. Figure 7This is a schematic diagram of another photovoltaic module-level power generation system provided in an embodiment of the present invention. Figure 6 and Figure 7 As shown, based on the above embodiments, optionally, the connection bus of the string power optimizer 20, the combiner module 30 and the inverter module 40 is a DC bus 50; the photovoltaic module-level power generation system also includes at least one of a DC load 60 or a DC power supply 70; wherein, the DC load 60 is coupled to the DC bus 50 and the DC power supply 70 is coupled to the DC bus 50.

[0067] In this system, DC bus 50 refers to an electrical conductor or wire used to transmit direct current, typically used to connect multiple devices in the system. It provides a unified power transmission path, allowing different components and loads to exchange and connect power through the bus. DC load 60 refers to devices or modules in the photovoltaic system that consume direct current; for example, DC load 60 could be an energy storage battery, charging pile, motor, LED light, electronic equipment, etc. DC power supply 70 refers to devices that provide direct current, such as energy storage batteries or other energy storage systems, or power generation systems.

[0068] Energy storage batteries refer to devices used to store electrical energy, typically including batteries or other types of energy storage systems (such as supercapacitors). Energy storage batteries can both absorb electrical energy as a load and release electrical energy as a power source. They can store energy when there is a surplus of electricity and release energy when demand increases, thus balancing power supply and demand and improving system reliability and stability. Charging stations are facilities for charging electric vehicles or other battery-powered devices, typically equipped with DC charging interfaces. Charging stations convert DC power from the source into voltage and current suitable for the electric vehicle's battery, providing fast and efficient charging services.

[0069] In this embodiment of the invention, by coupling the DC load 60 and the DC power supply 70 to the DC bus 50, the photovoltaic module-level power generation system can manage energy flow more effectively. When photovoltaic power generation is excessive, energy can be directly supplied to the DC load 60; while when photovoltaic power generation is insufficient, the system can automatically switch to the DC power supply 70, thereby achieving energy balance and stability.

[0070] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0071] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A photovoltaic module-level power generation system, characterized in that, include: Multiple photovoltaic strings, each photovoltaic string including at least two module-level power optimizers; wherein the input terminal of each module-level power optimizer is coupled to a photovoltaic module; and the output terminals of each module-level power optimizer are connected in series for output. The system comprises a string-level power optimizer, a combiner module, and an inverter module; wherein, some of the photovoltaic strings are coupled to the inverter module through the string-level power optimizer, which is configured one-to-one with each other; and some photovoltaic strings are coupled to the inverter module through the common combiner module.

2. The photovoltaic module-level power generation system according to claim 1, characterized in that, The photovoltaic string coupled to the string-level power optimizer is the first photovoltaic string, and the photovoltaic string coupled to the combiner module is the second photovoltaic string; The number of the first photovoltaic strings is less than the number of the second photovoltaic strings.

3. The photovoltaic module-level power generation system according to claim 2, characterized in that, The first photovoltaic string consists of one string; the second photovoltaic string consists of multiple strings.

4. The photovoltaic module-level power generation system according to any one of claims 1-3, characterized in that, The photovoltaic string coupled to the string-level power optimizer is the first photovoltaic string, and the photovoltaic string coupled to the combiner module is the second photovoltaic string; Wherein, the length of the first photovoltaic string is less than the length of the second photovoltaic string; and the difference in length between each second photovoltaic string is less than a set threshold.

5. The photovoltaic module-level power generation system according to any one of claims 1-3, characterized in that, The photovoltaic string coupled to the string-level power optimizer is the first photovoltaic string, and the photovoltaic string coupled to the combiner module is the second photovoltaic string; The illumination time of the first photovoltaic string is less than that of the second photovoltaic string.

6. The photovoltaic module-level power generation system according to claim 1, characterized in that, The photovoltaic string coupled to the combiner module is a second photovoltaic string; The second photovoltaic string also includes a protection unit, which is connected in series between the output terminal of the second photovoltaic string and the combiner module.

7. The photovoltaic module-level power generation system according to claim 6, characterized in that, The protection unit includes at least one of the following: anti-reverse diode, fuse, and protection switch.

8. The photovoltaic module-level power generation system according to claim 1, characterized in that, The correspondence between the component-level power optimizer and the photovoltaic module includes at least one of the following: The component-level power optimizer is coupled to one of the photovoltaic modules; The component-level power optimizer is coupled to at least two of the photovoltaic modules.

9. The photovoltaic module-level power generation system according to claim 1, characterized in that, The connection bus of the string power optimizer, the combiner module and the inverter module is a DC bus; The photovoltaic module-level power generation system further includes: a DC load and / or a DC power supply; wherein the DC load is coupled to the DC bus, and the DC power supply is coupled to the DC bus.

10. The photovoltaic module-level power generation system according to claim 9, characterized in that, The DC load includes at least one of an energy storage battery and a charging pile.

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