Photovoltaic power generation system

Abstract

The utility model provides a photovoltaic power generation system, which comprises a plurality of photovoltaic power generation subsystems, each photovoltaic power generation subsystem comprises at least one photovoltaic group string, an inverter and a distributed energy storage unit, the inverter is provided with an input end, a direct current output end and an alternating current output end, the input end is electrically connected with the at least one photovoltaic group string, and the alternating current output end is electrically connected with the distributed energy storage unit. The DC output end is electrically connected with the distributed energy storage unit, and the AC output end is electrically connected with load equipment and / or a power grid. Because each photovoltaic power generation subsystem is provided with an independent inverter, the distributed energy storage unit under each photovoltaic power generation subsystem can adapt to the optimal charging and discharging voltage through the inverter, so that the distributed energy storage unit can be fully charged and fully discharged. And therefore, the battery capacity utilization rate of each distributed energy storage unit in the photovoltaic power generation system can be maximized.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic technology, and in particular to a photovoltaic power generation system. Background Art

[0002] Photovoltaic units, inverters, and energy storage units together constitute a photovoltaic power generation system, which can be used to power the power grid and load equipment.

[0003] Existing photovoltaic power generation systems usually use large inverters and integrate multiple batteries into a whole. The electricity generated by the photovoltaic panels is charged by the inverter. However, since the capacity of each battery is different, charging with the same voltage will cause some batteries to not be fully charged and discharged for a long time, resulting in system capacity loss. Utility Model Content

[0004] The embodiments of the present application provide a photovoltaic power generation system to at least partially improve the above problems.

[0005] The implementation method of the present application is achieved through the following technical solutions.

[0006] An embodiment of the present application provides a photovoltaic power generation system, which includes a plurality of photovoltaic power generation subsystems, each of the plurality of photovoltaic power generation subsystems includes at least one photovoltaic string, an inverter and a distributed energy storage unit, the inverter having an input end, a DC output end and an AC output end, the input end being electrically connected to the at least one photovoltaic string, the DC output end being electrically connected to the distributed energy storage unit, and the AC output end being electrically connected to a load device and / or a power grid; wherein the inverter is used to perform voltage conversion on electric energy to adapt to the charging voltage of the distributed energy storage unit, thereby charging the distributed energy storage unit; the inverter is also used to perform voltage conversion according to the discharge voltage of the distributed energy storage unit, so that the distributed energy storage unit discharges to the load device and / or the power grid.

[0007] In some embodiments, the photovoltaic power generation system further includes a plurality of substrates, the plurality of substrates corresponding one-to-one to the plurality of photovoltaic power generation subsystems, each of the plurality of substrates having a photovoltaic slot, an inverter slot and an energy storage slot, the photovoltaic slot being used to assemble the at least one photovoltaic string, the inverter slot being used to assemble the inverter, and the energy storage slot being used to assemble the distributed energy storage unit.

[0008] In some embodiments, each of the plurality of photovoltaic power generation sub-systems is mounted on the plurality of substrates, respectively, and the plurality of substrates are interconnected and mounted and fixed on a roof of a building.

[0009] In some embodiments, the energy storage slots between the plurality of substrates are dispersedly arranged at intervals.

[0010] In some embodiments, the inverter slots between the plurality of substrates are arranged in dispersed intervals.

[0011] In some embodiments, the AC output end includes a first output end and a second output end, the first output end is used to be electrically connected to an external power grid and / or a first load, the second output end is used to be electrically connected to a second load, and the power-on priority of the second load is higher than that of the first load.

[0012] In some embodiments, the inverter further includes a controller, and the controller is used to control the opening or closing of the first output terminal.

[0013] In some embodiments, the at least one photovoltaic string includes a plurality of photovoltaic units, and the plurality of photovoltaic units are connected in series and / or in parallel to convert solar energy into electrical energy.

[0014] In some embodiments, the inverter is a microinverter.

[0015] In some embodiments, the inverters in the plurality of photovoltaic power generation subsystems are connected in parallel.

[0016] The utility model provides a photovoltaic power generation system, including multiple photovoltaic power generation subsystems, each photovoltaic power generation subsystem includes at least one photovoltaic string, an inverter and a distributed energy storage unit, the inverter has an input end, a DC output end and an AC output end, the input end is electrically connected to the at least one photovoltaic string, the DC output end is electrically connected to the distributed energy storage unit, and the AC output end is electrically connected to a load device and / or a power grid. Since each photovoltaic power generation subsystem is configured with an independent inverter, the distributed energy storage unit under each photovoltaic power generation subsystem can adapt the optimal charging and discharging voltage through the inverter, so that the distributed energy storage unit can be fully charged and fully discharged, which is beneficial to maximize the battery capacity utilization of each distributed energy storage unit under the photovoltaic power generation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the implementation mode of the present application, the drawings required for use in the description of the implementation mode will be briefly introduced below. Obviously, the drawings described below are only some implementation modes of the present utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic structural diagram of a photovoltaic power generation system provided in one embodiment of the present application is shown.

[0019] Figure 2 Another structural schematic diagram of a photovoltaic power generation system provided in an embodiment of the present application is shown.

[0020] Figure numerals: photovoltaic power generation system 1, photovoltaic power generation subsystem 10, photovoltaic string 110, photovoltaic unit 111, inverter 120, input terminal 121, DC output terminal 122, AC output terminal 123, first output terminal 1231, second output terminal 1232, controller 124, distributed energy storage unit 130, substrate 140, MPPT controller 150, power grid 20, load device 30, first load 310, second load 320. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the implementation mode of the present application will be clearly and completely described below in conjunction with the drawings in the implementation mode of the present application. Obviously, the described implementation mode is only a part of the implementation mode of the utility model, not all the implementation modes. Based on the implementation mode in the utility model, all other implementation modes obtained by those skilled in the art without making creative work are within the scope of protection of the utility model.

[0022] The technical solutions in the implementation modes of the present application will be described clearly and completely below in conjunction with the accompanying drawings in the implementation modes of the present application.

[0023] Photovoltaic power generation system is a device that converts solar energy into electrical energy. Photovoltaic units, inverters, and batteries together constitute a photovoltaic power generation system, which can be used to power the power grid and load equipment.

[0024] Existing photovoltaic power generation systems usually use large inverters and integrate batteries into a whole. The batteries are charged through photovoltaic units-inverters-grids-AC coupling. However, the charging efficiency of AC coupling charging is low. Specifically, the principle of AC coupling charging is to convert the AC power of the grid into a voltage suitable for battery charging through a transformer, and then convert the AC power into DC power through a rectifier to supply the battery. In this process, since the voltage and frequency of the AC power will be affected by the grid environment and load changes, the efficiency of AC coupling charging may be reduced in the actual charging process. In addition, the battery is formed by connecting each group of energy storage units in series and parallel. Since the cells of each energy storage unit in each energy storage unit group are different, the charging and / or discharging current of the energy storage unit with high internal resistance is low, and the charging and / or discharging current of the energy storage unit with low internal resistance is high. If the same voltage is used for charging, some energy storage units will not be fully charged and / or discharged for a long time, resulting in energy storage unit capacity loss. There are problems of capacity loss caused by series current mismatch and parallel voltage mismatch.

[0025] See also Figure 1 Based on the above problems, an embodiment of the present application provides a photovoltaic power generation system 1, which may include at least one photovoltaic power generation sub-system 10. The embodiment of the present application is explained by taking the photovoltaic power generation system 1 including multiple photovoltaic power generation sub-systems 10 as an example. It should be noted that the embodiment of the present application does not limit the specific number of photovoltaic power generation sub-systems 10, and can be flexibly set according to actual conditions.

[0026] Specifically, each photovoltaic power generation subsystem 10 may include multiple photovoltaic strings 110, inverters 120, and distributed energy storage units 130. It is understandable that the embodiment of the present application also does not limit the number of photovoltaic strings 110, which can be flexibly set according to actual conditions.

[0027] The photovoltaic string 110 can be used to absorb sunlight and convert solar energy into electrical energy. In the present embodiment, each photovoltaic power generation subsystem 10 may include at least one photovoltaic string 110. When multiple photovoltaic strings 110 are provided, the multiple photovoltaic strings 110 may be provided in parallel. This can increase the power generation of the entire photovoltaic power generation subsystem 10, and at the same time enable the entire photovoltaic power generation subsystem 10 to receive more sunlight, increase the absorption of sunlight, and thereby increase the power generation.

[0028] Furthermore, in each photovoltaic power generation subsystem 10, the photovoltaic string 110 may include a plurality of photovoltaic units 111 arranged in an array, and the plurality of photovoltaic units 111 are connected in series and / or in parallel to convert solar energy into electrical energy, which can also enable the entire photovoltaic power generation subsystem 10 to receive more sunlight, increase the amount of sunlight absorbed, and thus increase the amount of power generated. It should be noted that the embodiments of the present application do not limit the specific manner of the array, for example, in some embodiments, it may be a 3×6 array, in other embodiments, it may be a 4×5 array, etc., which may be specifically set according to actual conditions.

[0029] The inverter 120 can be used to convert the voltage of the electric energy to adapt to the charging voltage of the distributed energy storage unit 130, thereby charging the distributed energy storage unit 130, and the inverter 120 is also used to convert the voltage according to the discharge voltage of the distributed energy storage unit 130 so that the distributed energy storage unit 130 discharges to the load device 30 and / or the power grid 20.

[0030] Specifically, in this embodiment, the inverter 120 may have an input terminal 121, a DC output terminal 122, and an AC output terminal 123. The input terminal 121 may be electrically connected to at least one photovoltaic string 110. The photovoltaic string 110 may transmit electric energy to the inverter 120 through the input terminal 121. The DC output terminal 122 may be electrically connected to a distributed energy storage unit 130. The electric energy generated by the photovoltaic string 110 may charge the distributed energy storage unit 130 through the DC output terminal 122 of the inverter 120. Compared with the traditional method of charging the distributed energy storage unit 130 by AC coupling of the inverter 120, in this embodiment, the inverter 120 has a DC output terminal 122. Therefore, in this embodiment, the inverter 122 may charge the distributed energy storage unit 130 by DC coupling, and this charging method is more efficient. It should be noted that in this embodiment, the inverter 120 is a micro inverter, which can reduce the volume of the entire photovoltaic power generation system 1 and facilitate installation by users.

[0031] The distributed energy storage unit 130 can be used to store the electric energy generated by the photovoltaic string 110, and can be used to transmit the electric energy to the load device 30. It should be noted that the embodiment of the present application does not limit the specific structure of the distributed energy storage unit 130. For example, the distributed energy storage unit 130 can be a battery or a power station, etc., which is not limited here. For the sake of convenience, the distributed energy storage unit 130 is used as a battery as an example for explanation.

[0032] In this embodiment, a plurality of photovoltaic power generation subsystems 10 are provided, and the controller 124 of each photovoltaic power generation subsystem 10 is also used to independently control the distributed energy storage unit 130 connected thereto to charge or discharge. Since the battery cells of each distributed energy storage unit 130 are different, the charging and / or discharging current of the distributed energy storage unit 130 with high internal resistance is low, and the charging and / or discharging current of the distributed energy storage unit 130 with low internal resistance is high. If the distributed energy storage unit 130 is charged with the same voltage, some distributed energy storage units 130 may not be fully charged and / or discharged for a long time, thereby causing capacity loss of the distributed energy storage unit 130. Therefore, in this embodiment, the controller 124 in each photovoltaic power generation subsystem 10 charges and / or discharges the distributed energy storage unit 130 connected thereto separately, which can control the distributed energy storage unit 130 more accurately, thereby improving the charging efficiency and / or discharging efficiency of the distributed energy storage unit 130, thereby improving the service life of the distributed energy storage unit 130, and at the same time avoiding the problem of capacity loss caused by series current mismatch and parallel voltage mismatch caused by the traditional use of one inverter 120 to control the distributed energy storage unit 130 as a whole.

[0033] It is understandable that during the use of the distributed energy storage unit 130, the distributed energy storage unit 130 will inevitably age. When the distributed energy storage unit 130 ages, the distributed energy storage unit 130 needs to be replaced. If the distributed energy storage unit 130 with capacity loss is replaced, the new and old distributed energy storage units 130 will be mixed, which will accelerate the aging of the new distributed energy storage unit 130 and the mismatch of the capacity of the new and old distributed energy storage units 130. The old distributed energy storage unit 130 has a large internal resistance, so the temperature rises, which accelerates the aging of the distributed energy storage unit 130. When the new and old distributed energy storage units 130 are mixed, the capacity of the new distributed energy storage unit 130 can only be used in conjunction with the capacity of the old distributed energy storage unit 130, resulting in a serious capacity mismatch.

[0034] In addition, the high-voltage distributed energy storage units 130 have series losses and the barrel effect. Since the charging and / or discharging currents of the distributed energy storage units 130 are the same, but the capacities of different distributed energy storage units 130 are different, the distributed energy storage units 130 with small capacities are fully charged and discharged first, which in turn causes some distributed energy storage units 130 to be unable to be fully charged and discharged for a long time, resulting in capacity loss in the distributed energy storage unit 130 group.

[0035] In summary, by controlling each distributed energy storage unit 130 separately, it is also possible to share distributed energy storage units 130 of different capacities, lifespans, and types in the photovoltaic power generation system 1. The lifespan of the new distributed energy storage unit 130 will not be reduced after replacing it with a new distributed energy storage unit 130 due to damage or aging of individual distributed energy storage units 130. By controlling each distributed energy storage unit 130 separately, it is possible to maximize the utilization of the capacity and number of cycles of each distributed energy storage unit 130.

[0036] In this embodiment, the AC output terminal 123 of each photovoltaic power generation subsystem 10 is used to be electrically connected to the external power grid 20 and / or the load device 30, and the inverter 120 can also perform voltage conversion according to the discharge voltage of the distributed energy storage unit 130, so that the distributed energy storage unit 130 discharges to the load device 30 and / or the power grid 20. In other words, the electric energy generated by the photovoltaic string 110 can be used to supply power to the external power grid 20 and / or the load device 30 through the AC output terminal 123 of the inverter 120. It should be noted that the external power grid 20 is also electrically connected to the load device 30. When the photovoltaic string 110 receives sunlight, the photovoltaic string 110 can directly supply power to the load device 30. When the photovoltaic string 110 cannot receive sunlight, the external power grid 20 can directly supply power to the load device 30.

[0037] Specifically, in this embodiment, the AC output terminal 123 may include: a first output terminal 1231 and a second output terminal 1232, and the load device 30 may include a first load 310 and a second load 320, and the second load 320 has a higher power-on priority than the first load 320, that is, when the power is insufficient, the power supply of the second load 320 needs to be met first, and then the power supply of the first load 310 is met. The first load 310 may be an ordinary load, such as an ordinary household load, a factory production load, etc., and the second load 320 may be a critical load, such as a national defense load, a digital computer room load, etc.

[0038] More specifically, in one implementation, when the present embodiment is applied to a user's home, the first load 320 may be a lighting load, and the second load 320 may be a key electrical load such as a computer load.

[0039] In another embodiment, the first load 310 and the second load 320 can be set according to the user's preference. For example, the user can set a refrigerator load, a lighting load, or a water heater load as the second load 320, and the remaining household loads are set as the first load 310.

[0040] The first output terminal 1231 is used to be electrically connected to the external power grid 20 and / or the first load 310, and the external power grid 20 is arranged in parallel with the first load 310, and the second output terminal 1232 is used to be electrically connected to the second load 320. Separating the common load from the critical load can prevent the common load and the critical load from affecting each other. Specifically, when the external power grid 20 fails, the first output terminal 1231 will be disconnected, and the external power grid 20 cannot supply power to the first load 310 and the second load 320. At this time, the second output terminal 1232 is still electrically connected to the critical load. If the photovoltaic string 110 can receive sunlight at this time, the electric energy generated by the photovoltaic string 110 can be directly transmitted to the critical load, ensuring that the second load 320 can work normally without being affected when the external power grid 20 fails; if the photovoltaic string 110 cannot receive sunlight at this time, the distributed energy storage unit 130 can transmit electric energy to the inverter 120 through the DC output terminal 122, and then transmit the electric energy to the second load 320 through the second output terminal 1232 of the inverter 120, ensuring that the second load 320 can work normally without being affected when the external power grid 20 fails.

[0041] Furthermore, in one embodiment, the inverter 120 may also include a controller 124, which may be used to control the opening or closing of the first output terminal 1231. For example, when the distributed energy storage unit 130 is fully charged, the controller 124 may control the first output terminal 1231 to be closed, so as to avoid energy waste caused by overcharging of the distributed energy storage unit 130, and at the same time help to improve the service life of the distributed energy storage unit 130. When the distributed energy storage unit 130 is not fully charged or the external power grid 20 fails, the controller 124 may control the first output terminal 1231 to be opened, and the distributed energy storage unit 130 may continue to be charged or the distributed energy storage unit 130 may supply power to the second load 320.

[0042] It is understandable that in the daily use of the photovoltaic power generation system 1, due to different building orientations, surrounding buildings, tree shadows, between arrays, cloud cover and other shadow blocking scenarios, this will cause the photovoltaic string 110 to receive a changing amount of sunlight, which in turn causes the voltage of the electric energy generated by the photovoltaic string 110 to be different. In this embodiment, the inverter 120 can also have: a maximum power point tracking (MPPT) controller 150. The MPPT controller 150 can be electrically connected to the photovoltaic string 110 and to the power grid 20 and the load device 30. The MPPT controller 150 can detect the power generation voltage of the photovoltaic string 110 in real time and track the highest voltage and current values, so that the inverter 120 charges the distributed energy storage unit 130 with maximum power output. In this way, overcharging and / or discharging of the distributed energy storage unit 130 can be avoided, which is beneficial to improving the charging efficiency of the distributed energy storage unit 130, and can also improve the service life of the distributed energy storage unit 130.

[0043] In addition, each photovoltaic string 110 is connected to an MPPT controller 150 , so that each photovoltaic string 110 can transmit electrical energy to the inverter 120 at maximum power, thereby facilitating improving the power generation efficiency of the photovoltaic power generation system 1 .

[0044] Furthermore, in the present embodiment, a plurality of photovoltaic power generation subsystems 10 are provided, and the AC output terminals 123 of the plurality of photovoltaic power generation subsystems 10 are connected in parallel, and each photovoltaic power generation subsystem 10 outputs power to the external power grid 20 and / or the load device 30 at the same time, thereby increasing the capacity of the photovoltaic power generation system 1.

[0045] See also Figure 2In one embodiment, the photovoltaic power generation system 1 may further include a plurality of substrates 140, and the plurality of substrates 140 correspond one-to-one to the plurality of photovoltaic power generation subsystems 10. Each of the plurality of substrates 140 has a photovoltaic slot, an inverter slot, and an energy storage slot. The photovoltaic slot is used to assemble at least one photovoltaic string 110, the inverter slot is used to assemble the inverter 120, and the energy storage slot is used to assemble a distributed energy storage unit 130.

[0046] It should be noted that the present application does not restrict the connection between the photovoltaic string 110, the inverter 120 and the distributed energy storage unit 130 and the substrate 140. For example, in some embodiments, the photovoltaic string 110 can be bonded to the substrate 140, the inverter 120 can be fixed to the substrate 140 by bolts, and the distributed energy storage unit 130 can be snapped onto the substrate 140, etc. The specific settings can be made according to actual conditions.

[0047] In addition, the embodiments of the present application do not limit the specific material and structure of the substrate 140. For example, in some embodiments, the substrate 140 can be applied to the roof. In this case, the photovoltaic power generation system 1 can be used as a roof. Compared with the traditional roof, the roof has the function of photovoltaic power generation, which is beneficial to the use of sunlight. At this time, the substrate 140 can be made of high-strength waterproof insulating materials, such as polyurethane, polyvinyl chloride, polypropylene, polytetrafluoroethylene and other materials. Among them, polyurethane also has excellent elasticity and wear resistance, polyvinyl chloride also has excellent chemical corrosion resistance and wear resistance, polypropylene also has excellent heat resistance and corrosion resistance, polytetrafluoroethylene also has excellent wear resistance and high temperature resistance. The specific settings can be made according to actual conditions and are not limited here.

[0048] Furthermore, each of the multiple photovoltaic power generation subsystems 10 is respectively assembled on multiple substrates 140, and the multiple substrates 140 are interconnected and installed and fixed on the roof of the building. That is to say, the substrate 140 can also be set on the existing roof, for example, the substrate 140 can be fixedly set on the existing roof structure. Similarly, the embodiment of the present application does not limit the connection between the substrate 140 and the roof. For example, it can be directly bonded or snap-fitted, etc., and can be specifically set according to actual conditions. The interconnected installation can be understood as when the substrate 140 is set on the existing roof, the specific structure of the substrate 140 can be set according to the specific structure of the roof to adapt to the existing roof. For example, when the roof is a sloping roof, the substrate 140 can also be set to an inclined structure. When the roof is a flat structure, the substrate 140 can also be set to a flat structure.

[0049] It should be noted that the photovoltaic power generation system 1 provided in the embodiment of the present application is not limited to application on roofs. Specifically, the structure of the substrate 140 can be deformed and set according to the actual environment to adapt to different environments. For example, the photovoltaic power generation system 1 provided in the embodiment of the present application can also be set on flat ground, slopes and other scenes, which is not limited here.

[0050] In addition, the traditional photovoltaic power generation system 1 is usually a large inverter 120 connected to an integrated distributed energy storage unit 130. There is a large distance between the inverter 120 and the distributed energy storage unit 130 to avoid the heat generated by the distributed energy storage unit 130 and the inverter 120 during work affecting each other, which will cause the wiring between the inverter 120, the distributed energy storage unit 130 and the photovoltaic string 110 to be longer, which is not conducive to the installation of the entire photovoltaic power generation system 1. Compared with the traditional photovoltaic power generation system 1, the photovoltaic power generation system 1 provided in the embodiment of the present application divides the photovoltaic power generation system 1 into multiple photovoltaic power generation sub-systems 10. The photovoltaic strings 110, inverters 120 and distributed energy storage units 130 in each photovoltaic power generation sub-system 10 are smaller in size, and thus less heat is generated. Therefore, the photovoltaic strings 110, inverters 120 and distributed energy storage units 130 can be arranged more concentratedly, reducing the setting volume of the entire photovoltaic power generation system 1, while reducing the wiring length, thereby simplifying the installation of the photovoltaic power generation system 1.

[0051] Please continue reading Figure 2 Furthermore, in one embodiment, the energy storage slots between the multiple substrates 140 are dispersedly arranged at intervals, so that the distributed energy storage units 130 of the multiple photovoltaic power generation subsystems 10 can be distributed at intervals, which can avoid the concentration of the distributed energy storage units 130, resulting in the concentration of heat in the photovoltaic power generation system 1, causing local high temperature in the entire photovoltaic power generation system 1, and further causing damage to the distributed energy storage units 130.

[0052] Similarly, in one embodiment, the inverter slots between the multiple substrates 140 are dispersedly arranged at intervals, so that the inverters 120 of the multiple photovoltaic power generation subsystems 10 can be distributed at intervals. In this way, the inverters 120 can be concentrated, resulting in the concentration of heat in the photovoltaic power generation system 1, causing local high temperatures in the entire photovoltaic power generation system 1, and further causing damage to the inverter 120.

[0053] The working principle of the photovoltaic power generation system 1 provided in the embodiment of the present application is as follows:

[0054] First, the photovoltaic strings 110 in the photovoltaic power generation subsystem 10 absorb sunlight and convert solar energy into electrical energy. The electrical energy can be transmitted to the inverter 120 through the input terminal 121 of the inverter 120, and the distributed energy storage unit 130 is charged through the DC output terminal 122 of the inverter 120. Part of the electrical energy generated by the photovoltaic power generation subsystem 10 will be stored in the distributed energy storage unit 130, and the other part of the electrical energy will be transmitted to the power grid 20 and the first load 310 through the first output terminal 1231 of the AC output terminal 123, and transmitted to the second load 320 through the second output terminal 1232 of the AC output terminal 123.

[0055] When a fault occurs in the power grid 20, the power grid 20 cannot supply power to the first load 310 and the second load 320, and the first output terminal 1231 of the inverter 120 will be disconnected. At this time, the photovoltaic string 110 cannot supply power to the first load 310, but can supply power to the second load 320. At the same time, the distributed energy storage unit 130 can also supply power to the second load 320 to ensure the normal use of the second load 320.

[0056] The photovoltaic power generation system 1 provided in the embodiment of the present application is configured as a plurality of photovoltaic power generation subsystems 10, each photovoltaic power generation subsystem 10 includes at least one photovoltaic string 110, an inverter 120 and a distributed energy storage unit 130, the inverter 120 has an input terminal 121, a DC output terminal 122 and an AC output terminal 123, the input terminal 121 is electrically connected to at least one photovoltaic string 110, the DC output terminal 122 is electrically connected to the distributed energy storage unit 130, and the AC output terminal 123 is electrically connected to the load device 30 and / or the power grid 20. Since each photovoltaic power generation subsystem 10 is configured with an independent inverter 120, the distributed energy storage unit 130 under each photovoltaic power generation subsystem 10 can adapt the optimal charge and discharge voltage through the inverter 120, so that the distributed energy storage unit 130 can be fully charged and discharged, which is conducive to maximizing the battery capacity utilization rate of each distributed energy storage unit 130 under the photovoltaic power generation system 1.

[0057] In this utility model, unless otherwise clearly specified or limited, the terms "installation", "connection" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, an integral connection, or a transmission connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0058] In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as specific or special structures. The description of the term "some embodiments" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In the present utility model, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any at least one embodiment or example. In addition, those skilled in the art can combine and combine different embodiments or examples described in the present utility model and the features of different embodiments or examples without contradiction.

[0059] The above implementation modes are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned implementation modes, a person skilled in the art should understand that the technical solutions described in the aforementioned implementation modes can still be modified, or some of the technical features can be replaced by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various implementation modes of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A photovoltaic power generation system, characterized in that: The photovoltaic power generation system includes a plurality of photovoltaic power generation subsystems, each of the plurality of photovoltaic power generation subsystems includes at least one photovoltaic string, an inverter and a distributed energy storage unit, the inverter has an input end, a DC output end and an AC output end, the input end is electrically connected to the at least one photovoltaic string, the DC output end is electrically connected to the distributed energy storage unit, and the AC output end is electrically connected to a load device and / or a power grid; wherein, The inverter is used to convert the voltage of the electric energy to adapt to the charging voltage of the distributed energy storage unit, thereby charging the distributed energy storage unit; The inverter is further used to perform voltage conversion according to the discharge voltage of the distributed energy storage unit, so that the distributed energy storage unit discharges to the load device and / or the power grid.

2. The photovoltaic power generation system according to claim 1, characterized in that: The photovoltaic power generation system also includes multiple substrates, which correspond one-to-one to the multiple photovoltaic power generation subsystems. Each of the multiple substrates has a photovoltaic slot, an inverter slot and an energy storage slot. The photovoltaic slot is used to install the at least one photovoltaic string, the inverter slot is used to install the inverter, and the energy storage slot is used to install the distributed energy storage unit.

3. The photovoltaic power generation system according to claim 2, characterized in that: Each of the plurality of photovoltaic power generation sub-systems is respectively mounted on the plurality of substrates, and the plurality of substrates are interconnected and installed and fixed on the roof of the building.

4. The photovoltaic power generation system according to claim 3, characterized in that: The energy storage slots between the multiple substrates are dispersedly arranged at intervals.

5. The photovoltaic power generation system according to claim 3, characterized in that: The inverter slots between the multiple substrates are dispersedly arranged at intervals.

6. The photovoltaic power generation system according to claim 1, characterized in that: The AC output end includes a first output end and a second output end, the first output end is used to be electrically connected to an external power grid and / or a first load, the second output end is used to be electrically connected to a second load, and the second load has a higher power-on priority than the first load.

7. The photovoltaic power generation system according to claim 6, characterized in that: The inverter further includes a controller, and the controller is used to control the opening or closing of the first output terminal.

8. The photovoltaic power generation system according to claim 1, characterized in that: The at least one photovoltaic string includes a plurality of photovoltaic units, and the plurality of photovoltaic units are connected in series and / or in parallel to convert solar energy into electrical energy.

9. The photovoltaic power generation system according to claim 1, characterized in that: The inverter is a micro inverter.

10. The photovoltaic power generation system according to claim 1, characterized in that: The inverters in the plurality of photovoltaic power generation subsystems are arranged in parallel.

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