Photovoltaic storage system

Abstract

This application discloses a photovoltaic (PV) energy storage system, belonging to the field of photovoltaics. The PV energy storage system includes: a photovoltaic module; a conversion device for connecting to the power grid; an energy storage device connected between the photovoltaic module and the conversion device; and a control device for controlling the power transmission status between the photovoltaic module, the conversion device, and the energy storage device based on the grid electricity price and the power generation capacity of the photovoltaic module. This PV energy storage system, by setting up an energy storage device between the photovoltaic module and the conversion device, adjusts the power transmission status between the photovoltaic module, the conversion device, and the energy storage device according to the grid electricity price and the power generation capacity of the photovoltaic module, thereby improving economic efficiency while reducing the PV curtailment rate.

Description

Technical Field

[0001] This application pertains to the field of photovoltaics, and in particular relates to a photovoltaic-storage system. Background Technology

[0002] A photovoltaic (PV) energy storage system includes photovoltaic (PV) modules and PV inverters connecting the PV modules and the power grid. In related technologies, grid dispatching mainly relies on the power generation capacity of PV modules and load demand to achieve energy dispatch. However, due to fluctuations in grid electricity prices, this dispatching method is prone to causing significant curtailment of solar power, resulting in a certain degree of waste of solar energy. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a photovoltaic energy storage system that improves economic efficiency while reducing photovoltaic curtailment rate.

[0004] In a first aspect, this application provides an optical storage system, comprising: Photovoltaic modules; A conversion device for connecting to the power grid; An energy storage device is connected between the photovoltaic module and the conversion device; A control device is used to control the power transmission status between the photovoltaic module, the conversion device, and the energy storage device based on the electricity price of the power grid and the power generation capacity of the photovoltaic module.

[0005] According to the photovoltaic-storage system of this application, by setting up an energy storage device between the photovoltaic module and the conversion device, the power transmission status between the photovoltaic module, the conversion device and the energy storage device is adjusted according to the grid electricity price and the power generation capacity of the photovoltaic module, thereby improving economic efficiency while reducing the photovoltaic curtailment rate.

[0006] According to one embodiment of this application, the control device is used for: When the electricity price is greater than or equal to the first electricity selling price, at least one of the photovoltaic module and the energy storage device is controlled to supply electrical energy to the conversion device.

[0007] According to one embodiment of this application, the control device is used for: When the power generation capacity is greater than a preset power generation threshold, and the electricity price is greater than or equal to the second electricity selling price and less than the first electricity selling price, the photovoltaic module is controlled to supply power to the energy storage device and the conversion device.

[0008] According to one embodiment of this application, the control device is used for: When the power generation capacity is greater than a preset power generation threshold and the electricity price is less than the second electricity selling price, the photovoltaic module is controlled to supply power to the energy storage device.

[0009] According to one embodiment of this application, the control device is used for: When the power generation capacity is less than or equal to a preset power generation threshold, the energy storage device is controlled to supply electrical energy to the conversion device.

[0010] According to one embodiment of this application, the energy storage device includes: Energy storage module; A first switch, the first end of which is connected to the photovoltaic module, and the second end of which is connected to the energy storage module and the conversion device respectively; The control device is used to control the working state of the energy storage module, the on / off state of the first switch, and the opening / closing state of the conversion device.

[0011] According to one embodiment of this application, the energy storage module includes: Energy storage batteries; A boost / buck device is disposed between the energy storage battery and the second terminal. The control device is used to control the working state of the boost / buck device; the working state includes the open / closed state and the energy flow direction.

[0012] According to one embodiment of this application, when the electricity price is greater than or equal to the first electricity selling price... The control closes the first switch, shuts down the boost / blow-up device, and turns on the conversion device; or, The first switch is closed, the boost / buck device is turned on, and the energy flow path is adjusted so that the energy storage battery flows to the conversion device, and the conversion device is turned on.

[0013] According to one embodiment of this application, when the power generation capacity is greater than a preset power generation threshold, and the electricity price is greater than or equal to a second electricity selling price and less than a first electricity selling price, The system controls the closure of the first switch, activates the boost / buck device, adjusts the energy flow path to flow from the photovoltaic module to the energy storage battery, and activates the conversion device.

[0014] According to one embodiment of this application, when the power generation capacity is greater than a preset power generation threshold and the electricity price is less than a second electricity selling price, The system controls the closure of the first switch, activates the boost / buck device, adjusts the energy flow path to flow from the photovoltaic module to the energy storage battery, and shuts down the conversion device.

[0015] According to one embodiment of this application, when the power generation capacity is less than or equal to a preset power generation threshold... The control disconnects the first switch, turns on the boost / buck device, adjusts the energy flow path to flow from the energy storage battery to the conversion device, and turns on the conversion device.

[0016] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects: By installing an energy storage device between photovoltaic modules and conversion devices, the power transmission status between photovoltaic modules, conversion devices, and energy storage devices can be adjusted according to the grid electricity price and the power generation capacity of photovoltaic modules, thereby improving economic efficiency while reducing the photovoltaic curtailment rate.

[0017] Furthermore, by adjusting the electricity price of the grid and the power generation capacity of the photovoltaic modules, the power transmission status among the photovoltaic modules, conversion devices, and energy storage devices can be regulated. When the electricity price is high, the energy generated by the photovoltaic system and / or stored in the energy storage device is transmitted to the grid to obtain higher returns. When the electricity price is moderate, excess photovoltaic energy is transmitted to the energy storage device for storage, so that the grid can still be supplied normally if the electricity price increases or the photovoltaic modules cannot generate power normally. When the photovoltaic modules cannot generate power normally, the connection between the photovoltaic modules and other devices is cut off to protect the photovoltaic modules, and the energy storage device transmits power to the grid. This not only ensures the normal power demand of the grid but also increases returns, reduces the photovoltaic curtailment rate, and extends the lifespan of the photovoltaic modules. It takes into account various complex application scenarios such as climate, environment, and grid fluctuations, and achieves a dynamic balance between improving solar energy utilization, increasing economic benefits, extending lifespan, and meeting electricity demand.

[0018] Furthermore, by cooperating with the first switch and the step-up / step-down device, multiple energy flow paths between photovoltaic modules, energy storage batteries, and the grid side can be switched. The circuit structure is simple, the design cost is low, and the space occupied is small.

[0019] Furthermore, by disconnecting the output terminal of a photovoltaic module from other components when its power generation capacity is low, the risk of the output terminal being damaged by high-voltage impacts can be reduced, thereby increasing the lifespan of the photovoltaic module.

[0020] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is one of the structural schematic diagrams of the photovoltaic energy storage system provided in the embodiments of this application; Figure 2 This is the second schematic diagram of the structure of the photovoltaic energy storage system provided in the embodiments of this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0023] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0024] In the description of this application, "multiple" means two or more.

[0025] The optical storage system provided in this application will be described below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0026] It should be noted that the photovoltaic and energy storage system of this application can be applied to photovoltaic power plants, or small-scale photovoltaic scenarios such as residential rooftop photovoltaics, small-scale industrial and commercial power plants, and building-integrated photovoltaics.

[0027] like Figure 1 As shown, the photovoltaic-energy storage system includes: photovoltaic modules, conversion devices, energy storage devices, and control devices.

[0028] Photovoltaic modules are used to convert solar energy into electrical energy. The power generation capacity of photovoltaic modules is affected by factors such as weather, time, climate, light intensity, as well as the installation location and orientation of the photovoltaic modules.

[0029] The conversion device is used to connect to the power grid and to convert direct current (DC) into alternating current (AC) for transmission to the grid. In some embodiments, the conversion device may be a photovoltaic inverter.

[0030] Energy storage devices are connected between photovoltaic modules and conversion devices, and have functions such as storing electrical energy output by photovoltaic modules and transmitting electrical energy to conversion devices.

[0031] The control device is used to control the power transmission status between the photovoltaic module, the conversion device and the energy storage device based on the grid electricity price, the power generation capacity of the photovoltaic module and the state of charge of the energy storage device.

[0032] The power transmission state may include the power transmission direction, which may include at least one of the following: power transmission from photovoltaic modules to energy storage devices, power transmission from photovoltaic modules to conversion devices and then to the power grid, and power transmission from energy storage devices to conversion devices and then to the power grid.

[0033] The electricity price on the power grid is the price at which the power grid sells electricity.

[0034] In some embodiments, the energy storage device and the control device can be integrated to reduce the space occupied.

[0035] like Figure 2 As shown, in some embodiments, the energy storage device includes an energy storage module and a first switch S1.

[0036] In this embodiment, the energy storage module is used to store electrical energy.

[0037] The first terminal of the first switch S1 is connected to the photovoltaic module, and the second terminal is connected to the energy storage module and the conversion device, respectively. The first switch S1 is electrically connected to the control device, which controls its on / off state. The on / off state includes being on or off.

[0038] In some embodiments, the electrical connection may include wired electrical connections and radio connections, such as wireless communication connections, etc., which are not limited herein.

[0039] In some embodiments, the first switch S1 may be a relay, a transistor, etc., which is not limited herein.

[0040] The control device is used to control the operating state of the energy storage module, the on / off state of the first switch S1, and the on / off state of the conversion device. The operating state of the energy storage module includes being on or off.

[0041] like Figure 2 As shown, in some embodiments, the energy storage module includes: an energy storage battery and a buck-boost device.

[0042] In this embodiment, the energy storage battery may include one or more battery packs, and each battery pack may include one or more individual battery cells.

[0043] A boost / buck device is disposed between the energy storage battery and the second terminal of the first switch S1, and is used to boost or buck the electrical energy output from or input to the energy storage battery. In some embodiments, the boost / buck device can be a bidirectional boost / buck device, such as a bidirectional boost / buck converter.

[0044] The control device is electrically connected to the buck-boost device and is used to control the operating status of the buck-boost device; the operating status includes the on / off state and the direction of energy flow. It can be understood that when the buck-boost device is on, adjusting its operating status can change the direction of energy flow, i.e., controlling whether energy is input from the photovoltaic modules to the energy storage device, or output from the energy storage device to the conversion device; when the buck-boost device is off, the energy storage device cannot transmit energy or receive externally input energy.

[0045] According to the photovoltaic-storage system provided in the embodiments of this application, the switching of multiple energy flow paths between photovoltaic modules, energy storage batteries and the grid side can be realized through the cooperation of the first switch S1 and the step-up / step-down device. The circuit structure is simple, the design cost is low, and the space occupied is small.

[0046] In some embodiments, multiple combinations can be pre-set based on the different electricity prices on the grid and the power generation capacity of the photovoltaic modules, and one or more operating modes can be set for each combination, with each operating mode corresponding to a different energy flow pattern. Switching between different operating modes is achieved by adjusting the on / off state of the first switch S1, the operating state of the step-up / step-down device, and the operating state of the conversion device.

[0047] In actual implementation, the on / off state of the first switch S1, the working state of the step-up / step-down device, and the working state of the conversion device can be adaptively adjusted according to the electricity price sold by the grid and the power generation capacity of the photovoltaic modules. This adjusts the direction of power transmission, so that when the power generation capacity of the photovoltaic modules is large, the surplus power is transmitted to the energy storage device for storage; when the power generation capacity of the photovoltaic modules is insufficient, the energy storage device provides power to the grid; and when the electricity price sold by the grid is high, as much power as possible is provided to the grid, thereby reducing the photovoltaic curtailment rate and improving economic efficiency.

[0048] According to the photovoltaic-storage system provided in the embodiments of this application, by setting up an energy storage device between the photovoltaic module and the conversion device, the power transmission status between the photovoltaic module, the conversion device and the energy storage device is adjusted according to the grid electricity price and the power generation capacity of the photovoltaic module, thereby improving economic efficiency while reducing the photovoltaic curtailment rate.

[0049] The specific implementation method of this optical energy storage system will be explained below.

[0050] In some embodiments, the control device is used to: control at least one of the photovoltaic module and the energy storage device to supply electrical energy to the conversion device when the electricity price is greater than or equal to a first electricity selling price.

[0051] In this embodiment, the first electricity selling price can be based on user-defined settings, such as statistics from electricity selling prices under historical profitable conditions.

[0052] When the electricity selling price is greater than or equal to the first electricity selling price, it is considered that the current grid electricity selling price is high. At least one of the photovoltaic modules and energy storage devices is controlled to supply power to the conversion device, so as to meet the grid load demand and obtain as much revenue as possible.

[0053] In practice, when the price of electricity sold by the grid is high, the device that supplies power to the grid can be selected by combining the current power generation capacity of the photovoltaic modules, the current state of charge of the energy storage device, and the grid load demand, thereby taking into account the grid load demand, the photovoltaic curtailment rate, and economic benefits.

[0054] For example, when the electricity price is greater than or equal to the first electricity selling price and the photovoltaic module has a large power generation capacity, the photovoltaic module can be controlled to supply power to the conversion device.

[0055] When the electricity price is greater than or equal to the first electricity selling price and the photovoltaic module's power generation capacity is small or even zero, control the energy storage device to supply power to the conversion device.

[0056] When the electricity price is greater than or equal to the first electricity selling price and the grid load demand is high, control the photovoltaic modules and energy storage devices to supply power to the conversion device together.

[0057] In some embodiments, the control device is used to: control the photovoltaic module to deliver electrical energy to the energy storage device and the conversion device when the power generation capacity is greater than a preset power generation threshold and the electricity price is greater than or equal to the second electricity selling price and less than the first electricity selling price.

[0058] In this embodiment, the second electricity selling price is lower than the first electricity selling price. The second electricity selling price can be based on a user-defined setting, such as a positive value close to 0.

[0059] When the selling price of electricity is greater than or equal to the second selling price, the current selling price of electricity from the power grid is considered not negative. When the selling price of electricity is greater than or equal to the second selling price but less than the first selling price, the current selling price of electricity from the power grid is considered to be within a moderate range.

[0060] The preset power generation threshold can be set by the user. When the power generation capacity exceeds the preset threshold, the photovoltaic module is considered to be generating power normally.

[0061] In actual implementation, when the grid electricity price is in a moderate range and the photovoltaic modules can generate electricity normally, the photovoltaic modules can be controlled to simultaneously supply electricity to the energy storage device and the conversion device. While the photovoltaic modules provide electricity to the grid to meet the grid load demand, some photovoltaic energy can also be stored in the energy storage device so that it can be delayed in being supplied to the grid when the grid electricity price increases, thereby obtaining higher economic benefits.

[0062] In some embodiments, the control device is used to: control the photovoltaic module to deliver electrical energy to the energy storage device when the power generation capacity is greater than a preset power generation threshold and the electricity price is less than a second electricity selling price.

[0063] In this embodiment, when the grid electricity price is less than the second electricity price, it can be approximated that the electricity price is 0 or negative.

[0064] In practice, if the grid electricity price is low, the photovoltaic modules are controlled to supply electricity to the energy storage device to store the photovoltaic energy, reduce the curtailment rate, and facilitate the delayed transmission to the grid when the grid electricity price increases, so as to obtain higher economic benefits.

[0065] In some embodiments, the control device is used to: control the energy storage device to supply electrical energy to the conversion device when the power generation capacity is less than or equal to a preset power generation threshold.

[0066] In this embodiment, if the photovoltaic module has a low power generation capacity or no power generation capacity temporarily, the energy storage device is controlled to transmit the stored electrical energy to the grid through the conversion device to meet the grid's load demand. At the same time, certain economic benefits can still be obtained even when the photovoltaic module cannot generate electricity normally.

[0067] During the research and development process, the inventors discovered that electricity prices are dynamic and change. In related technologies, when photovoltaic power plants face dynamic electricity prices or even negative electricity prices, there is a lack of effective countermeasures. They often continue to supply power to the grid, which affects revenue. They may even shut down the photovoltaic power plant during periods of negative electricity prices, wasting a lot of solar energy and affecting revenue. In addition, the procedures for replacing grid-connected equipment in photovoltaic power plants are cumbersome.

[0068] In this application, by setting up an energy storage device between the photovoltaic module and the conversion device, the power transmission status between the photovoltaic module, the conversion device, and the energy storage device is adjusted according to the grid electricity price and the power generation capacity of the photovoltaic module. Without replacing the grid-connected inverter, it can achieve the following: when the electricity price is high, the photovoltaic power generation and / or the energy stored in the energy storage device is transmitted to the grid to obtain higher returns; when the electricity price is moderate, the excess photovoltaic energy is transmitted to the energy storage device for storage, so that the grid can still be supplied normally in the event of subsequent increases in electricity prices or photovoltaic modules failing to generate electricity normally. This ensures the normal electricity demand of the grid while increasing returns and reducing the curtailment rate. It also takes into account various complex application scenarios such as climate, environment, and grid fluctuations, achieving a dynamic balance between energy conservation and environmental protection, guaranteed benefits, and electricity demand, thereby improving the user experience.

[0069] In some embodiments, the control device is used to: when the power generation capacity is less than or equal to a preset power generation threshold, control the disconnection of the connection path between the photovoltaic module and the energy storage device, and disconnect the connection path between the photovoltaic module and the conversion device, such as controlling the first switch S1 to open.

[0070] According to the photovoltaic energy storage system provided in the embodiments of this application, by cutting off the connection between the output end of the photovoltaic module and other components when the power generation capacity of the photovoltaic module is low, the risk of the output end of the photovoltaic module being damaged by high voltage impact due to its inability to withstand high voltage can be reduced, thereby improving the service life of the photovoltaic module.

[0071] The following is combined with Figure 2 The specific circuit structure will be explained in detail to illustrate the above-mentioned energy flow implementation method.

[0072] In some embodiments, when the electricity price is greater than or equal to the first electricity selling price... When the first switch S1 is closed, the boost / buckling device is shut down, and the switching device is turned on; or, Control the closure of the first switch S1, turn on the boost / buck device, adjust the energy flow path to flow from the energy storage battery to the conversion device, and turn on the conversion device.

[0073] In this embodiment, if the price of electricity sold by the grid is high, the energy of the photovoltaic modules and / or energy storage devices can be transmitted to the grid.

[0074] If all the energy of the photovoltaic modules needs to be transmitted to the grid for sale, the first switch S1 is in the on state, and the energy of the photovoltaic modules is transmitted to the grid side through the photovoltaic inverter. The bidirectional buck-boost converter does not work.

[0075] If the energy of the energy storage device and the photovoltaic module needs to be transmitted to the grid for sale, the first switch S1 is in the on state. The energy of the photovoltaic module is transferred to the DC input port of the photovoltaic inverter. The energy of the energy storage battery is transferred to the DC input port of the photovoltaic inverter through the bidirectional buck-boost converter. The photovoltaic inverter then transfers the energy of the photovoltaic module at the DC input port and the energy transferred to the DC input port by the bidirectional buck-boost converter to the grid side.

[0076] If the energy from the energy storage device needs to be transmitted to the grid for sale, the energy from the energy storage battery is transmitted to the DC input port of the photovoltaic inverter via a bidirectional buck-boost converter, and the photovoltaic inverter then transmits the energy to the grid side.

[0077] In some embodiments, when the power generation capacity exceeds a preset power generation threshold, and the electricity price is greater than or equal to the second electricity selling price and less than the first electricity selling price, Control the closing of the first switch S1, turn on the step-up and step-down device, adjust the energy flow path to flow from the photovoltaic module to the energy storage battery, and turn on the conversion device.

[0078] In this embodiment, if the electricity price sold by the grid is reasonable and the photovoltaic modules can generate electricity normally, part of the energy of the photovoltaic modules can be transmitted to the grid and part can be transmitted to the energy storage device for storage.

[0079] In this case, the first switch S1 is in the on state, and the energy of the photovoltaic module is transferred to the grid side through the photovoltaic inverter. At the same time, the bidirectional buck-boost converter converts the energy of the photovoltaic module into the energy storage battery for storage.

[0080] In some embodiments, when the power generation capacity is greater than a preset power generation threshold and the state of charge of the energy storage device is greater than a first state of charge threshold, the first switch S1 is closed, the step-up / step-down device is turned on, the energy flow path is adjusted to flow from the photovoltaic module to the energy storage battery, and the conversion device is turned on.

[0081] In this embodiment, the first state of charge threshold is a relatively high threshold. When the state of charge is greater than the first state of charge threshold, it indicates that the remaining capacity of the energy storage battery is relatively high. In this case, the energy storage battery may not be able to absorb all the electrical energy transmitted by the photovoltaic module. Therefore, the energy of the photovoltaic module can be controlled to be partially transferred to the energy storage battery for storage, and the remaining part can be transferred to the energy storage device for storage.

[0082] In some embodiments, when the power generation capacity exceeds a preset power generation threshold and the electricity price is lower than the second electricity selling price, Control the closing of the first switch S1, turn on the step-up and step-down device, adjust the energy flow path to flow from the photovoltaic module to the energy storage battery, and turn off the conversion device.

[0083] In this embodiment, if the electricity price sold by the grid is low or even negative, and the photovoltaic modules are able to generate electricity normally, all the energy of the photovoltaic modules can be controlled to be transferred to the energy storage device for storage, and the flow path between the photovoltaic modules and the grid can be closed.

[0084] In this situation, the first switch S1 is in the on state, the control device controls the photovoltaic inverter to stop working, and the bidirectional buck-boost converter converts the energy of the photovoltaic module into the energy storage battery for storage.

[0085] In some embodiments, when the power generation capacity is less than or equal to a preset power generation threshold... The control disconnects the first switch S1, turns on the boost / buck device, adjusts the energy flow path to flow from the energy storage battery to the conversion device, and turns on the conversion device.

[0086] In this embodiment, if the photovoltaic module is currently unable to generate electricity normally or has a low output voltage, such as in scenarios with weak or no sunlight, the energy storage device can transmit electrical energy to the grid side for sale, and close the flow path between the photovoltaic module, the energy storage device, and the grid.

[0087] In this configuration, the first switch S1 is open. The energy from the energy storage battery is transferred to the DC input port of the photovoltaic inverter via the bidirectional buck-boost converter, and then transmitted to the grid side via the photovoltaic inverter. By disconnecting the first switch S1 to cut off the connection between the output terminal of the photovoltaic module and the photovoltaic inverter and energy storage device, the risk of the output terminal of the photovoltaic module being damaged by high-voltage surges can be reduced, thereby improving the service life of the photovoltaic module.

[0088] According to the photovoltaic-storage system provided in this application embodiment, the power transmission status between the photovoltaic module, conversion device, and energy storage device is adjusted based on the grid electricity price and the power generation capacity of the photovoltaic module. When the electricity price is high, the photovoltaic power generation and / or the energy stored in the energy storage device are transmitted to the grid to obtain higher returns. When the electricity price is moderate, excess photovoltaic energy is transmitted to the energy storage device for storage, so that the grid can still be supplied normally in the event of subsequent increases in electricity prices or photovoltaic modules failing to generate power normally. When the photovoltaic module fails to generate power normally, the connection between the photovoltaic module and other devices is disconnected to protect the photovoltaic module, and the energy storage device transmits power to the grid. While ensuring the normal power demand of the grid, it also improves returns, reduces the photovoltaic curtailment rate, and extends the service life of the photovoltaic module. It takes into account various complex application scenarios such as climate, environment, and grid fluctuations, and achieves a dynamic balance between improving solar energy utilization, improving economic benefits, extending service life, and meeting power demand.

[0089] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0090] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0091] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0092] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0093] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A photovoltaic energy storage system, characterized in that, include: Photovoltaic modules; A conversion device for connecting to the power grid; An energy storage device is connected between the photovoltaic module and the conversion device; A control device is used to control the power transmission status between the photovoltaic module, the conversion device, and the energy storage device based on the electricity price of the power grid and the power generation capacity of the photovoltaic module.

2. The photovoltaic energy storage system according to claim 1, characterized in that, The control device is used for: When the electricity price is greater than or equal to the first electricity selling price, at least one of the photovoltaic module and the energy storage device is controlled to supply electrical energy to the conversion device.

3. The photovoltaic energy storage system according to claim 1, characterized in that, The control device is used for: When the power generation capacity is greater than a preset power generation threshold, and the electricity price is greater than or equal to the second electricity selling price and less than the first electricity selling price, the photovoltaic module is controlled to supply power to the energy storage device and the conversion device.

4. The photovoltaic energy storage system according to claim 1, characterized in that, The control device is used for: When the power generation capacity is greater than a preset power generation threshold and the electricity price is less than the second electricity selling price, the photovoltaic module is controlled to supply power to the energy storage device.

5. The photovoltaic energy storage system according to claim 1, characterized in that, The control device is used for: When the power generation capacity is less than or equal to a preset power generation threshold, the energy storage device is controlled to supply electrical energy to the conversion device.

6. The photovoltaic energy storage system according to any one of claims 1-5, characterized in that, The energy storage device includes: Energy storage module; A first switch, the first end of which is connected to the photovoltaic module, and the second end of which is connected to the energy storage module and the conversion device respectively; The control device is used to control the working state of the energy storage module, the on / off state of the first switch, and the opening / closing state of the conversion device.

7. The photovoltaic energy storage system according to claim 6, characterized in that, The energy storage module includes: Energy storage batteries; A boost / buck device is disposed between the energy storage battery and the second terminal. The control device is used to control the working state of the boost / buck device; the working state includes the open / closed state and the energy flow direction.

8. The photovoltaic energy storage system according to claim 7, characterized in that, If the electricity price is greater than or equal to the first electricity selling price. The control closes the first switch, shuts down the boost / blow-up device, and turns on the conversion device; or, The first switch is closed, the boost / buck device is turned on, and the energy flow path is adjusted so that the energy storage battery flows to the conversion device, and the conversion device is turned on.

9. The photovoltaic energy storage system according to claim 7, characterized in that, When the power generation capacity is greater than a preset power generation threshold, and the electricity price is greater than or equal to the second electricity selling price and less than the first electricity selling price, The system controls the closure of the first switch, activates the boost / buck device, adjusts the energy flow path to flow from the photovoltaic module to the energy storage battery, and activates the conversion device.

10. The photovoltaic energy storage system according to claim 7, characterized in that, When the power generation capacity is greater than a preset power generation threshold and the electricity price is less than the second electricity selling price, The system controls the closure of the first switch, activates the boost / buck device, adjusts the energy flow path to flow from the photovoltaic module to the energy storage battery, and shuts down the conversion device.

11. The photovoltaic energy storage system according to claim 7, characterized in that, When the power generation capacity is less than or equal to a preset power generation threshold. The control disconnects the first switch, turns on the boost / buck device, adjusts the energy flow path to flow from the energy storage battery to the conversion device, and turns on the conversion device.

Images