Photovoltaic-energy storage coupled module

Abstract

A photovoltaic-energy storage coupled module, belonging to the technical field of power electronics. The photovoltaic-energy storage coupled module comprises a photovoltaic array, a DC / DC converter and an energy storage module. The DC / DC converter comprises an input interface and an output interface. The photovoltaic array is connected to the input interface, and the energy storage module is connected to the output interface to form a first power supply path. After being connected in series to the input interface or the output interface of the DC / DC converter, the photovoltaic array as a whole is connected to the energy storage module to form a first power supply circuit.

Description

Optical-storage coupling module

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 202510100186.6, filed on January 21, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of power electronics technology, and more specifically, to a photoelectric-storage coupling module and its control method, and a photoelectric-storage coupling system. Background Technology

[0004] Currently, existing photovoltaic-storage systems generally connect to the grid separately via transformers, in the form of energy storage power stations and photovoltaic power stations. Photovoltaic power stations mainly consist of photovoltaic arrays, which can be composed of a large number of photovoltaic panels. A centralized inverter converts the direct current (DC) output from the photovoltaic array into alternating current (AC), which is then stepped up to a higher voltage level by a step-up transformer before being connected to the grid. Energy storage power stations include battery banks, energy storage converters, battery management systems, and energy management systems. Energy storage converters enable bidirectional power conversion between the battery banks and the grid. However, existing photovoltaic-storage systems have a drawback: they require high current-carrying capacity from the electrical and power electronic components used in the DC / DC converters. Summary of the Invention

[0005] This application provides an optical-storage coupling module and its control method, as well as an optical-storage coupling system, to reduce the current carrying capacity requirements of various electrical and power electronic devices in a DC / DC converter.

[0006] In a first aspect, embodiments of this application provide a photovoltaic-storage coupling module, which includes: a photovoltaic array, a DC / DC converter, and an energy storage module; the DC / DC converter includes an input interface and an output interface, the photovoltaic array is connected to the input interface, and the energy storage module is connected to the output interface to form a first power supply path; the photovoltaic array is connected in series with the input interface or the output interface of the DC / DC converter, and then the whole is connected to the energy storage module to form a first power supply loop.

[0007] In the above technical solution, the photovoltaic array is connected in series with the input or output interface of the DC / DC converter. The photovoltaic array and the DC / DC converter are connected as a whole to the energy storage module. A portion of the output power of the photovoltaic array is directly supplied to the energy storage module through this series path. The role of the DC / DC converter in this photovoltaic-energy storage coupling module is a series boost partial power converter. The DC / DC converter only processes a portion of the output power of the photovoltaic array, not all of it. The power electronic devices and other electrical devices in the DC / DC converter do not need to withstand the maximum voltage of the submodule, which reduces the power processing requirements of the DC / DC converter. The current carrying capacity requirements of each electrical device and power electronic device in the DC / DC converter are low, thereby increasing the application range of the photovoltaic-energy storage coupling module. It can also reduce the size of each electrical device and power electronic device in the DC / DC converter, thereby reducing the overall size of the DC / DC converter and submodule. Furthermore, since it is not necessary to use electrical devices and power electronic devices with high current carrying capacity, it can reduce costs to a certain extent. Furthermore, compared to the power exchange method in related technologies where photovoltaic-storage systems require multiple converters, in this embodiment, after coupling the photovoltaic array with the DC / DC converter, the DC power output by the photovoltaic array can be partially exchanged by the DC / DC converter and then stored by the energy storage module. This reduces the number of conversions between the photovoltaic power station and the energy storage power station, reduces system losses, and also reduces the losses of power electronic devices by processing part of the power.

[0008] In some embodiments, the target electrical quantity output by the photovoltaic array and the sum / difference between the target electrical quantities input / output by the DC / DC converter are clamped by the target electrical quantity of the energy storage module.

[0009] In the above technical solution, the output target electrical quantity of the photovoltaic array is clamped by the electrical quantity of the energy storage module, and the sum / difference of the output / input target electrical quantity of the DC / DC converter is fixed by using the electrical quantity of the energy storage module as a constant value, thereby achieving the regulation of the photovoltaic array.

[0010] In some embodiments, the sum of the output voltage of the photovoltaic array and the output voltage of the DC / DC converter is clamped by the voltage of the energy storage module.

[0011] In the above technical solution, the output voltage of the photovoltaic array is clamped by the output voltage of the energy storage module, and the sum of the output voltage of the DC / DC converter is clamped. By using the constant voltage of the energy storage module, the relationship between the output voltage of the photovoltaic array and the output voltage of the DC / DC converter is fixed, so as to realize the regulation of the photovoltaic array by controlling the output voltage of the DC / DC converter, and the regulation of the output power of the photovoltaic array is more convenient.

[0012] In some embodiments, the photovoltaic array includes positive and negative terminals, the input interface of the DC / DC converter includes a first input terminal and a second input terminal, and the output interface of the DC / DC converter includes a first output terminal and a second output terminal; the photovoltaic array is connected in series with the output interface of the DC / DC converter, including:

[0013] The positive terminal of the photovoltaic array is electrically connected to the first input terminal and the second output terminal of the DC / DC converter.

[0014] In the above technical solution, the photovoltaic array is connected in series with the output interface of the DC / DC converter, and the photovoltaic array and DC / DC converter are connected in parallel with the energy storage module. A portion of the output power of the photovoltaic array is directly supplied to the energy storage module through this series path. The role of the DC / DC converter in this photovoltaic-energy storage coupling module is a series boost partial power converter. The DC / DC converter only processes a portion of the output power of the photovoltaic array, not all of it. The power electronic devices and other electrical devices in the DC / DC converter do not need to withstand the maximum voltage of the submodule, which reduces the power processing requirements of the DC / DC converter. The current carrying capacity requirements of each electrical device and power electronic device in the DC / DC converter are low, thereby increasing the application range of the photovoltaic-energy storage coupling module. It can also reduce the size of each electrical device and power electronic device in the DC / DC converter, thereby reducing the overall size of the DC / DC converter and submodule. Furthermore, since it is not necessary to use electrical devices and power electronic devices with high current carrying capacity, it can reduce costs to a certain extent.

[0015] In some embodiments, the sum of the output voltage of the photovoltaic array and the input voltage of the DC / DC converter is clamped by the voltage of the energy storage module.

[0016] In the above technical solution, the output voltage of the photovoltaic array is clamped by the output voltage of the energy storage module, and the sum of the output voltage of the photovoltaic array and the input voltage of the DC / DC converter is fixed by using the constant voltage of the energy storage module. This makes it easier to regulate the output power of the photovoltaic array by controlling the output voltage of the DC / DC converter.

[0017] In some embodiments, the photovoltaic array includes a positive terminal and a negative terminal, the input interface of the DC / DC converter includes a first input terminal and a second input terminal, and the output interface of the DC / DC converter includes a first output terminal and a second output terminal; the photovoltaic array is connected in series with the input interface of the DC / DC converter, including: the first output terminal of the DC / DC converter is electrically connected to the positive terminal of the photovoltaic array; and the negative terminal of the photovoltaic array is electrically connected to the first input terminal of the DC / DC converter.

[0018] In the above technical solution, the photovoltaic array is connected in series with the input interface of the DC / DC converter, and the photovoltaic array and DC / DC converter are connected in parallel with the energy storage module. A portion of the output power of the photovoltaic array is directly supplied to the energy storage module through this series path. The role of the DC / DC converter in this photovoltaic-energy storage coupling module is a series boost partial power converter. The DC / DC converter only processes a portion of the output power of the photovoltaic array, not all of it. The power electronic devices and other electrical devices in the DC / DC converter do not need to withstand the maximum voltage of the submodule, which reduces the power processing requirements of the DC / DC converter. The current carrying capacity requirements of each electrical device and power electronic device in the DC / DC converter are low, thereby increasing the application range of the photovoltaic-energy storage coupling module. It can also reduce the size of each electrical device and power electronic device in the DC / DC converter, thereby reducing the overall size of the DC / DC converter and submodule. Furthermore, since it is not necessary to use electrical devices and power electronic devices with high current carrying capacity, it can reduce costs to a certain extent.

[0019] In some embodiments, the output current of the photovoltaic array and the sum / difference of the input / output current of the DC / DC converter are clamped by the current of the energy storage module.

[0020] In the above technical solution, the output current of the photovoltaic array is clamped by the output current of the energy storage module, and the sum / difference of the output / input current of the DC / DC converter is fixed by using the current of the energy storage module as a constant value. This fixes the relationship between the output current of the photovoltaic array and the output / input current of the DC / DC converter, thereby enabling the photovoltaic array to be regulated by controlling the output voltage of the DC / DC converter.

[0021] In some embodiments, the photovoltaic-storage coupling module further includes a controller, and the DC / DC converter further includes a control terminal; the controller is connected to the control terminal of the DC / DC converter; the controller is used to control the output voltage and / or current of the DC / DC converter to perform maximum power point tracking control on the photovoltaic array.

[0022] In the above technical solution, the output voltage and / or current of the DC / DC converter are controlled by the controller to perform maximum power point tracking control on the photovoltaic array. This enables maximum power point tracking (MPPT) control of the photovoltaic array output by controlling the DC / DC converter, without the need for an additional optimizer for photovoltaic MPPT control.

[0023] In some embodiments, voltage regulator components are connected between the input interfaces and / or output interfaces of the DC / DC converter.

[0024] In the above technical solution, by connecting the input interface and / or output interface of the DC / DC converter through the voltage regulator component, the input voltage and / or output voltage of the DC / DC converter can be stabilized, thereby improving the operational stability of the photovoltaic-storage coupling module and improving the accuracy of photovoltaic array control.

[0025] In some embodiments, the voltage regulator component includes a capacitor.

[0026] In the above technical solution, connecting the input and / or output interfaces of the DC / DC converter with capacitors can stabilize the input and / or output voltage of the DC / DC converter. The components used are simple, without increasing the complexity of the circuit, which can improve the operational stability of the photovoltaic-storage coupling module and improve the accuracy of photovoltaic array control.

[0027] In some embodiments, the DC / DC converter employs a dual active bridge structure.

[0028] In the above technical solution, the DC / DC converter adopts a dual active bridge structure, which can realize the control of the photovoltaic array output without the need to add an additional optimizer to control the photovoltaic array output.

[0029] In some embodiments, the DC / DC converter is an isolated DC / DC converter.

[0030] In the above technical solution, by using an isolated DC / DC converter, the insulation requirements for the input and output sides of the DC / DC converter can be reduced, and the complexity of engineering implementation can be reduced.

[0031] In some embodiments, the energy storage module includes parallel energy storage cabinets; each energy storage cabinet is composed of multiple battery cells connected in series and parallel.

[0032] In the above technical solution, by using an energy storage cabinet composed of multiple battery cells connected in series and parallel to form an energy storage module, the energy storage capacity is stronger and more stable.

[0033] In some embodiments, the power module adopts a half-bridge structure or a full-bridge structure.

[0034] In the above technical solutions, by adopting a half-bridge or full-bridge structure for the power module, the operation of the optical-storage coupling module is more stable and efficient.

[0035] Secondly, embodiments of this application provide a photovoltaic-storage coupling system, the photovoltaic-storage coupling system comprising: at least one power module, the power module being connected to the photovoltaic-storage coupling module as described in any of the first aspects, the power module forming a second power supply path with the photovoltaic array, and / or, the power module forming a third power supply path with the energy storage module.

[0036] In the above technical solutions, by employing any of the aforementioned photovoltaic-storage coupling modules, the power processing requirements of the DC / DC converter can be reduced, and the current-carrying capacity requirements of the various electrical and power electronic components in the DC / DC converter are lower. This expands the application range of the photovoltaic-storage coupling module and reduces the size of the various electrical and power electronic components in the DC / DC converter, thereby reducing the overall size of the DC / DC converter, sub-modules, and modular multilevel converter system. Furthermore, since it is not necessary to use electrical and power electronic components with high current-carrying capacity, costs can be reduced to a certain extent. Moreover, compared to the method in related technologies where photovoltaic-storage systems require multiple stages of converters for power exchange, in this embodiment, after coupling the DC / DC converter and the photovoltaic array, the DC power output from the photovoltaic array can be partially exchanged by the DC / DC converter and then stored by the energy storage module. This reduces the number of conversions between the photovoltaic power station and the energy storage power station, reduces system losses, and also reduces the losses of power electronic components by processing a portion of the power.

[0037] In some embodiments, the optical-storage coupling system is a DC-connected optical-storage system, a modular multilevel converter-type optical-storage system, or a cascaded optical-storage system.

[0038] In the above technical solutions, by adopting any of the aforementioned opto-storage coupling modules, the power processing requirements of the DC / DC converter can be reduced, and the current carrying capacity requirements of each electrical and power electronic device in the DC / DC converter are low. This can improve the application range of the opto-storage coupling module, and also reduce the size of each electrical and power electronic device in the DC / DC converter, thereby reducing the overall size of the DC / DC converter, sub-modules, and modular multilevel converter system. Furthermore, since it is not necessary to use electrical and power electronic devices with high current carrying capacity, the cost can be reduced to a certain extent.

[0039] Furthermore, the modular multilevel converter type photovoltaic energy storage system, by adopting any of the aforementioned photovoltaic energy storage coupling modules and utilizing the cascading of power modules, is equivalent to connecting the power modules in series, which can increase the voltage of the photovoltaic energy storage system and thus increase the photovoltaic energy storage capacity.

[0040] Furthermore, DC direct-connected photovoltaic-storage systems using any of the aforementioned photovoltaic-storage coupling modules can be applied to scenarios such as DC power transmission and distribution networks, overcoming the AC harmonic problems present in the aforementioned scenarios in related technologies, and are more friendly to batteries and photovoltaic-storage systems.

[0041] Furthermore, AC direct-connected photovoltaic-storage systems using any of the aforementioned photovoltaic-storage coupling modules can be directly connected to the AC power grid, offering more application scenarios and better adaptability.

[0042] Thirdly, embodiments of this application provide a control method for an optical-storage coupling module as described in any of the first aspects, the control method comprising:

[0043] Obtain the maximum power point of the photovoltaic array at the target time;

[0044] Based on the maximum power point of the photovoltaic array at the target time, the output voltage of the DC / DC converter is controlled to perform maximum power point tracking control on the photovoltaic array.

[0045] In the above technical solution, the output voltage of the photovoltaic array is adjusted by regulating the output voltage of the DC / DC converter, thereby achieving MPPT control of the photovoltaic array. MPPT control of the photovoltaic array can be performed through the DC / DC converter without the need for an additional optimizer, which can reduce costs to a certain extent.

[0046] In some embodiments, obtaining the maximum power point of the photovoltaic array at a target time includes:

[0047] Obtain the output voltage and output current of the photovoltaic array at the target moment;

[0048] Based on the output voltage and output current of the photovoltaic array at the target time, the maximum power point of the photovoltaic array at the target time is obtained.

[0049] In the above technical solution, by obtaining the maximum power point of the photovoltaic array at the target time based on the output voltage and output current of the photovoltaic array, the maximum power point of the photovoltaic array at the target time can be obtained more quickly and accurately, thereby enabling faster and more accurate MPPT control of the photovoltaic array.

[0050] In some embodiments, controlling the output voltage of the DC / DC converter based on the maximum power point of the photovoltaic array at a target time includes:

[0051] Based on the maximum power point of the photovoltaic array at the target time, obtain the reference output voltage of the DC / DC converter;

[0052] The output voltage of the DC / DC converter is controlled based on the reference output voltage.

[0053] In the above technical solution, the output voltage of the photovoltaic array is adjusted by regulating the output voltage of the DC / DC converter, thereby achieving MPPT control of the photovoltaic array. MPPT control of the photovoltaic array can be performed through the DC / DC converter without the need for an additional optimizer, which can reduce costs to a certain extent.

[0054] In some embodiments, obtaining the reference output voltage of the DC / DC converter based on the maximum power point of the photovoltaic array at the target time includes:

[0055] Based on the maximum power point of the photovoltaic array at the target time, obtain the target voltage corresponding to the maximum power point of the photovoltaic array at the target time, and obtain the voltage of the energy storage module;

[0056] The reference output voltage is obtained based on the target voltage and the voltage of the energy storage module.

[0057] In the above technical solution, the reference output voltage of the DC / DC converter is obtained based on the target voltage corresponding to the maximum power point of the photovoltaic array at the target time and the voltage of the energy storage module. Using the reference output voltage of the DC / DC converter as the control target, the output voltage of the DC / DC converter is adjusted to achieve control over the output voltage U of the photovoltaic array. pv The adjustment ultimately achieves MPPT control of the photovoltaic array. It can perform MPPT control of the photovoltaic array through the DC / DC converter without the need for an additional optimizer, which can reduce costs to a certain extent. Attached Figure Description

[0058] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 is a schematic diagram of the structure of the optical-storage coupling module in the related technology;

[0060] Figure 2 is a schematic diagram of one of the optical-storage coupling modules provided in some embodiments of this application;

[0061] Figure 3 is a schematic diagram of the DC / DC converter provided in some embodiments of this application;

[0062] Figure 4 is a second schematic diagram of the structure of the optical-storage coupling module provided in some embodiments of this application;

[0063] Figure 5 is a third schematic diagram of the structure of the optical-storage coupling module provided in some embodiments of this application;

[0064] Figure 6 is a partial structural schematic diagram of an optical-storage coupling module provided in some embodiments of this application;

[0065] Figure 7 is a schematic diagram of the optical-storage coupling module provided in some embodiments of this application;

[0066] Figure 8 is a second partial structural schematic diagram of the optical-storage coupling module provided in some embodiments of this application;

[0067] Figure 9 is a schematic diagram of the structure of the optical-storage coupling module provided in some embodiments of this application;

[0068] Figure 10 is a schematic diagram of the structure of a modular multilevel converter system provided in some embodiments of this application;

[0069] Figure 11 is a schematic diagram of the structure of a DC direct-connected energy storage system provided in some embodiments of this application;

[0070] Figure 12 is a schematic diagram of the structure of a modular multilevel converter type converter valve provided in some embodiments of this application;

[0071] Figure 13 is a schematic diagram of the structure of a cascaded converter valve provided in some embodiments of this application;

[0072] Figure 14 is a flowchart illustrating the control method of the optical-storage coupling module provided in some embodiments of this application;

[0073] Figure 15 is a control block diagram of an optical-storage coupling module provided in some embodiments of this application. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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 embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0075] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0076] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0077] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0078] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0079] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0080] In this embodiment, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged after discharge to activate the active materials and continue to be used. The battery cell is used to store or provide electrical energy.

[0081] The battery cell can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and the embodiments of this application are not limited to this.

[0082] Battery cells can be cylindrical, flat, cuboid, or other shapes, and this application embodiment is not limited to any of these. Battery cells are generally classified into three types according to their packaging method: cylindrical battery cells, square battery cells, and pouch battery cells, and this application embodiment is not limited to any of these types either.

[0083] A battery cell includes a casing, electrode components, and electrolyte. The casing houses the electrode components and electrolyte. The electrode components consist of a positive electrode, a negative electrode, and a separator. The battery cell primarily functions by the movement of metal ions between the positive and negative electrode components. The positive electrode includes a positive current collector and a positive active material layer. The positive current collector includes a current collector body and a positive electrode tab. The positive active material layer is coated on the surface of the current collector body, while the positive electrode tab is not coated with the positive active material layer and protrudes from the current collector body. Taking a lithium-ion battery as an example, the material of the positive current collector can be aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode includes a negative current collector and a negative active material layer. The negative current collector includes a current collector body and a negative electrode tab. The negative active material layer is coated on the surface of the current collector body, while the negative electrode tab is not coated with the negative active material layer and protrudes from the current collector body. The negative electrode current collector can be made of copper, and the negative electrode active material can be carbon or silicon, etc. To ensure that a large current can be passed without melting, there are multiple positive electrode tabs stacked together, and there are multiple negative electrode tabs stacked together.

[0084] The separator can be made of PP (polypropylene) or PE (polyethylene), etc. Furthermore, the electrode assembly can be a wound structure or a stacked structure; the embodiments of this application are not limited to these.

[0085] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0086] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0087] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0088] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0089] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0090] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0091] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0092] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0093] The inventors discovered that the Modular Multilevel Converter (MMC) has found some applications in the field of photovoltaic grid connection. For example, by adopting a grid connection method that combines photovoltaics with a cascaded topology, the voltage level can be increased to 35kV, and the system losses are reduced.

[0094] In photovoltaic grid-connected systems, sub-modules (SMs) often employ full-power converters, such as non-isolated BOOST converters or isolated dual-active-bridge (DAB) converters. When using full-power converters, the power electronic and other electrical components must withstand the maximum voltage of the sub-module and have high current-carrying capacity requirements. Furthermore, to meet full-power delivery requirements, especially when the sub-module's power and voltage ratings are high, the cost and size of a single sub-module are also significant.

[0095] For a conventional photovoltaic-storage coupling module, the full-power converter in this sub-module needs to process the entire output power of the photovoltaic array. The power electronic devices and other electrical devices in the full-power converter need to withstand the maximum voltage of the sub-module and have high requirements for current carrying capacity.

[0096] Figure 1 shows the structure of a conventional photovoltaic-storage coupling module. The following explanation, using the photovoltaic-storage coupling module shown in Figure 1 as an example, illustrates the principle of a full-power converter processing the entire output power of a photovoltaic array. It is understood that although the full-power converter in Figure 1 is a BOOST converter, those skilled in the art will understand that when using other full-power converters, the full-power converter also processes the entire output power of the photovoltaic array.

[0097] For this BOOST converter, P DC / DC =I out ×U bat =I pv ×U pv Among them, P DC / DC =I out ×U bat The power level after passing through the BOOST converter is compared with the power level P output by the photovoltaic array. pv =I pv ×U pv They are equal. Therefore, the IGBT in the topology shown in Figure 1 needs to withstand the maximum voltage of the submodule and needs a large current carrying capacity.

[0098] Based on the above considerations, and in order to solve the problem, the inventors, through in-depth research, designed a photovoltaic-storage coupling module. The photovoltaic array is connected in series with the output of a DC / DC converter, and the photovoltaic array and DC / DC converter are connected in parallel with the energy storage module. The DC / DC converter can be an isolated series boost partial power converter.

[0099] It is understandable that a DC / DC converter is also called a DC-DC converter. The symbol " / " in DC / DC converter means "to". A DC / DC converter is a device that performs conversion from DC to DC.

[0100] This photovoltaic-storage coupling module structure, by employing a topology based on a series-connected power converter, reduces the power handling requirements of the DC / DC converter compared to a topology based on a full-power DC / DC converter. It also lowers the current-carrying capacity requirements of the various power electronic and other electrical components within the DC / DC converter. Furthermore, it allows for MPPT control of the photovoltaic array output and provides high-voltage isolation functionality.

[0101] The following description, in conjunction with the accompanying drawings, details the optical-storage coupling module and its control method, as well as the modular multilevel converter system provided in this application, through specific embodiments and application scenarios.

[0102] Referring to Figure 2, a photovoltaic-storage coupling module 100 includes: a photovoltaic array 111, a DC / DC converter 112, and an energy storage module 120; the DC / DC converter 112 includes an input interface and an output interface, the photovoltaic array 111 is connected to the input interface, and the energy storage module 120 is connected to the output interface to form a first power supply path; the photovoltaic array 111 is connected in series with the input interface or the output interface of the DC / DC converter 112, and then the whole is connected to the energy storage module 120 to form a first power supply loop.

[0103] In actual implementation, the main topology of the photovoltaic-storage coupling module 100 is an integrated system consisting of a photovoltaic array 111 and a DC / DC converter 112, which is highly coupled to the energy storage module 120 in a modular form. The DC / DC converter 112 is a series boost partial-power DC / DC converter, which is highly coupled to the photovoltaic array 111, together forming the photovoltaic power generation module 110.

[0104] The photovoltaic-storage coupling module 100 may mainly include components such as a photovoltaic array 111, a DC / DC converter 112, and an energy storage module 120. The energy storage module 120 can be used to store or provide electrical energy. In some embodiments, the energy storage module 120 may employ an energy storage module from related technologies.

[0105] In some embodiments, the DC / DC converter 112 may include an input interface and an output interface. DC power is input to the DC / DC converter 112 through the input interface, converted by the DC / DC converter 112, and output through the output interface. The input interface of the DC / DC converter 112 is connected to the photovoltaic array 111, and the output interface of the DC / DC converter 112 is connected to the energy storage module 120, thereby forming a power supply path from the photovoltaic array 111 through the input interface of the DC / DC converter 112, the internal conversion circuit of the DC / DC converter 112, and the output interface of the DC / DC converter 112, to the energy storage module 120. This power supply path is the first power supply path.

[0106] In actual implementation, the photovoltaic array 111 and the DC / DC converter 112 can be connected to the energy storage module 120. Within this assembly, the photovoltaic array 111 can be connected in series with either the input or output interface of the DC / DC converter 112. Through this connection, the photovoltaic array 111, the DC / DC converter 112, and the energy storage module 120 can form a new power supply loop outside the first power supply path. This new power supply loop is the first power supply loop.

[0107] It should be noted that the term "path" refers to the path through which electric current can pass. The term "loop" refers to a closed circuit. A closed circuit is a circuit in which a charge can return to its original position after completing one revolution along the circuit.

[0108] It should be noted that, unlike related technologies, in this embodiment, the photovoltaic array 111 and the input or output interface of the DC / DC converter 112 are connected in series. Thus, the DC / DC converter 112 can be used as an isolated series partial power converter or a non-isolated series partial power converter, only processing part of the output power of the photovoltaic array 111 instead of all of the output power. The power electronic devices and other electrical devices in the DC / DC converter 112 do not need to withstand the maximum voltage of the submodule, and the requirements for their current carrying capacity are reduced.

[0109] It should be noted that in the photovoltaic-storage coupling module 100, the DC / DC converter 112 is generally used to boost the output voltage of the photovoltaic array 111, that is, the output voltage of the DC / DC converter 112 is greater than the input voltage of the DC / DC converter 112. Therefore, in the embodiments of this application, the DC / DC converter 112 can be used as an isolated series boost partial power converter or a non-isolated series boost partial power converter. Figure 3 shows one principle of the DC / DC converter 112.

[0110] In some embodiments, the photovoltaic array 111 can be a photovoltaic array composed of photovoltaic modules connected in series and parallel. Series and parallel connection means that some photovoltaic modules can be connected in series and some photovoltaic modules can be connected in parallel.

[0111] In some embodiments, the specific structures of the input and output sides of the DC / DC converter 112 are not limited in this application. For example, the input or output side of the DC / DC converter 112 can adopt a full-bridge or half-bridge structure.

[0112] In some embodiments, based on Figure 2, Figures 4-5 show a further refined structure of the optical-storage coupling module.

[0113] It should be noted that by connecting the photovoltaic array 111 in series with the input or output interface of the DC / DC converter 112, a portion of the output power of the photovoltaic array 111 can be directly supplied to the energy storage module 120 from this series path (i.e., the first power supply circuit), while the other portion of the output power is transmitted through the DC / DC converter 112 to adjust the power level.

[0114] According to the photovoltaic-storage coupling module provided in the embodiments of this application, the photovoltaic array is connected in series with the input or output interface of the DC / DC converter. The photovoltaic array and the DC / DC converter are connected as a whole to the energy storage module. A portion of the output power of the photovoltaic array is directly supplied to the energy storage module through this series path. The DC / DC converter in this photovoltaic-storage coupling module is a series boost partial power converter. The DC / DC converter only processes a portion of the output power of the photovoltaic array, not all of it. The power electronic devices and other electrical devices in the DC / DC converter do not need to withstand the maximum voltage of the submodule, which can reduce the power processing requirements of the DC / DC converter. The current carrying capacity requirements of each electrical device and power electronic device in the DC / DC converter are low, thereby improving the application range of the photovoltaic-storage coupling module. It can also reduce the size of each electrical device and power electronic device in the DC / DC converter, thereby reducing the overall size of the DC / DC converter and submodule. Furthermore, since it is not necessary to use electrical devices and power electronic devices with high current carrying capacity, it can reduce costs to a certain extent. Furthermore, compared to the power exchange method in related technologies where photovoltaic-storage systems require multiple converters, in this embodiment, after coupling the photovoltaic array with the DC / DC converter, the DC power output by the photovoltaic array can be partially exchanged by the DC / DC converter and then stored by the energy storage module. This reduces the number of conversions between the photovoltaic power station and the energy storage power station, reduces system losses, and also reduces the losses of power electronic devices by processing part of the power.

[0115] In some embodiments, the sum / difference between the target electrical quantity of the output of the photovoltaic array 111 and the target electrical quantity of the input / output of the DC / DC converter 112 is clamped by the target electrical quantity of the energy storage module 120.

[0116] In actual implementation, for the topology shown in Figure 2, depending on the way the photovoltaic array 111 is connected to the DC / DC converter 112, the sum of the target output electrical quantity of the photovoltaic array 111 and the target output electrical quantity of the DC / DC converter 112 is clamped by the target output electrical quantity of the energy storage module 120; or the difference between the target output electrical quantity of the photovoltaic array 111 and the target output electrical quantity of the DC / DC converter 112 is clamped by the target output electrical quantity of the energy storage module 120; or the sum of the target output electrical quantity of the photovoltaic array 111 and the target input electrical quantity of the DC / DC converter 112 is clamped by the target output electrical quantity of the energy storage module 120; or the difference between the target output electrical quantity of the photovoltaic array 111 and the target input electrical quantity of the DC / DC converter 112 is clamped by the target output electrical quantity of the energy storage module 120.

[0117] It should be noted that the symbol " / " in "input / output target electrical quantity" and "sum / difference" represents "or". Therefore, "the sum / difference of the output target electrical quantity of photovoltaic array 111 and the input / output target electrical quantity of DC / DC converter 112 is clamped by the target electrical quantity of energy storage module 120" can include the following situations: the sum of the output target electrical quantity of photovoltaic array 111 and the input target electrical quantity of DC / DC converter 112 is clamped by the target electrical quantity of energy storage module 120; the difference between the output target electrical quantity of photovoltaic array 111 and the input target electrical quantity of DC / DC converter 112 is clamped by the target electrical quantity of energy storage module 120; the sum of the output target electrical quantity of photovoltaic array 111 and the output target electrical quantity of DC / DC converter 112 is clamped by the target electrical quantity of energy storage module 120; and the difference between the output target electrical quantity of photovoltaic array 111 and the output target electrical quantity of DC / DC converter 112 is clamped by the target electrical quantity of energy storage module 120.

[0118] It should be noted that the term "clamping" refers to limiting electrical quantities such as voltage or current at a target node in a circuit to a certain value. Limiting voltage is called "voltage clamping," and limiting current is called "current clamping." For example, the sum of the output target electrical quantity of the photovoltaic array 111 and the input target electrical quantity of the DC / DC converter 112 is clamped by the target electrical quantity of the energy storage module 120; the difference between the output target electrical quantity of the photovoltaic array 111 and the input target electrical quantity of the DC / DC converter 112 is clamped by the target electrical quantity of the energy storage module 120; the sum of the output target electrical quantity of the photovoltaic array 111 and the output target electrical quantity of the DC / DC converter 112 is clamped by the target electrical quantity of the energy storage module 120; and the difference between the output target electrical quantity of the photovoltaic array 111 and the output target electrical quantity of the DC / DC converter 112 is clamped by the target electrical quantity of the energy storage module 120. These terms respectively refer to the photovoltaic array... The sum of the output target electrical quantity of photovoltaic array 111 and the input target electrical quantity of DC / DC converter 112 is limited to be equal to the target electrical quantity of energy storage module 120; the difference between the output target electrical quantity of photovoltaic array 111 and the input target electrical quantity of DC / DC converter 112 is limited to be equal to the target electrical quantity of energy storage module 120; the sum of the output target electrical quantity of photovoltaic array 111 and the output target electrical quantity of DC / DC converter 112 is limited to be equal to the target electrical quantity of energy storage module 120; and the difference between the output target electrical quantity of photovoltaic array 111 and the output target electrical quantity of DC / DC converter 112 is limited to be equal to the target electrical quantity of energy storage module 120.

[0119] According to the photovoltaic-storage coupling module provided in the embodiments of this application, the output target electrical quantity of the photovoltaic array is clamped by the electrical quantity of the energy storage module, and the sum / difference of the output / input target electrical quantity of the DC / DC converter is fixed by using the electrical quantity of the energy storage module as a constant value, thereby fixing the relationship between the output target electrical quantity of the photovoltaic array and the output / input target electrical quantity of the DC / DC converter, and realizing the regulation of the photovoltaic array.

[0120] In some embodiments, the sum of the output voltage of the photovoltaic array 111 and the output voltage of the DC / DC converter 112 is clamped by the voltage of the energy storage module 120.

[0121] In actual implementation, for the topology shown in Figure 6, the target electrical quantity can be voltage. The output voltage U of the photovoltaic array 111... pv The sum of the output voltage U1 of the DC / DC converter 112 and the voltage U of the energy storage module 120 bat Clamping satisfies the following formula:

[0122] U1+U pv =U bat .

[0123] According to the photovoltaic-storage coupling module provided in the embodiments of this application, the output voltage of the photovoltaic array and the output voltage of the DC / DC converter are clamped by the output voltage of the energy storage module. By using the constant voltage of the energy storage module, the relationship between the output voltage of the photovoltaic array and the output voltage of the DC / DC converter is fixed, so as to realize the regulation of the photovoltaic array by controlling the output voltage of the DC / DC converter, and the regulation of the output power of the photovoltaic array is more convenient.

[0124] Referring to Figure 6, in some embodiments, the photovoltaic array 111 includes a positive terminal and a negative terminal, the input interface of the DC / DC converter 112 includes a first input terminal and a second input terminal, and the output interface of the DC / DC converter 112 includes a first output terminal and a second output terminal; the photovoltaic array 112 is connected in series with the output interface of the DC / DC converter 112, including: the positive terminal of the photovoltaic array 111 is electrically connected to the first input terminal and the second output terminal of the DC / DC converter 112.

[0125] In actual implementation, based on the conventional photoelectric energy storage coupling module, the positive terminal of the energy storage module 120 can be electrically connected to the first output terminal of the DC / DC converter 112 to form a feedforward path, i.e., the first power supply circuit.

[0126] According to Kirchhoff's laws, the following voltage-current relationship can be obtained: U2 = U pv ;

[0127] U1+U pv =U bat ;

[0128] I1=I out ;

[0129] I out +I2=I pv .

[0130] The output power of the controlled device photovoltaic array 111 is:

[0131] P pv =U pv ×I pv .

[0132] The power consumed by DC / DC converter 112 is: P = U² × I² = U pv ×(I pv -I out )=U pv ×I pv -U pv ×I out .

[0133] Comparison yields:

[0134] P < P pv .

[0135] Therefore, only a small portion of the total output power of the photovoltaic array 111 flows through the DC / DC converter 112, while the remaining main photovoltaic power is directly output through the feedforward path. This design optimizes a range of aspects of the DC / DC converter 112, including efficiency, power density, cost, and heat dissipation.

[0136] In the above formula, U1 and I1 represent the output voltage and output current of DC / DC converter 112, respectively; U2 and I2 represent the input voltage and input current of DC / DC converter 112, respectively; U pv and I pv These represent the output voltage and output current of photovoltaic array 111, respectively; U bat Indicates the voltage of energy storage module 120; I out This represents the current in the feedforward path.

[0137] In some embodiments, the first output terminal and the second output terminal of the DC / DC converter 112 can also be electrically connected through an output capacitor C1; the first input terminal and the second input terminal of the DC / DC converter 112 can be electrically connected through an input capacitor C2; the first output terminal of the DC / DC converter 112 and the positive terminal of the energy storage module 120 can also be electrically connected through a filter inductor L.

[0138] It should be noted that the voltage Uc of the output capacitor C1 is equal to the output voltage of the DC / DC converter 112, and the current I of the filter inductor L is equal to the voltage Uc of the output capacitor C1.L It is equal to the input current of DC / DC converter 112.

[0139] It is understandable that when the output power P of the photovoltaic array... pv Under the same conditions, compared to a regular submodule, this topology satisfies P <P pv The power rating of the DC / DC converter 112 is reduced, and the current carrying capacity requirement of the IGBT (Insulated-Gate Bipolar Transistor) is reduced.

[0140] In some embodiments, the negative terminal of the photovoltaic array 111 is electrically connected to the second input terminal of the DC / DC converter 112.

[0141] According to the photovoltaic-storage coupling module provided in this application embodiment, the photovoltaic array is electrically connected to the first input terminal and the second output terminal of the DC / DC converter. The photovoltaic array and the DC / DC converter are connected in parallel with the energy storage module. A portion of the output power of the photovoltaic array is directly supplied to the energy storage module through a series path. The DC / DC converter in this photovoltaic-storage coupling module is a series boost partial power converter. The DC / DC converter only processes a portion of the output power of the photovoltaic array, not all of it. The power electronic devices and other electrical devices in the DC / DC converter do not need to withstand the maximum voltage of the submodule, which can reduce the power processing requirements of the DC / DC converter. The current carrying capacity requirements of each electrical device and power electronic device in the DC / DC converter are low, thereby improving the application range of the photovoltaic-storage coupling module. It can also reduce the size of each electrical device and power electronic device in the DC / DC converter, thereby reducing the overall size of the DC / DC converter and submodule. Furthermore, since it is not necessary to use electrical devices and power electronic devices with high current carrying capacity, it can reduce costs to a certain extent.

[0142] In some embodiments, the sum of the output voltage of the photovoltaic array 111 and the input voltage of the DC / DC converter 112 is voltage clamped by the energy storage module 120.

[0143] In actual implementation, for the topology shown in Figure 8, the target electrical quantity can be voltage. The output voltage U of the photovoltaic array 111... pv The sum of the input voltage U2 of the DC / DC converter 112 and the voltage U of the energy storage module 120 is... bat Clamping satisfies the following formula:

[0144] U bat =U2+U pv .

[0145] According to the photovoltaic-storage coupling module provided in the embodiments of this application, the output voltage of the photovoltaic array is clamped by the output voltage of the energy storage module, and the sum of the output voltage of the photovoltaic array and the input voltage of the DC / DC converter is fixed by using the constant voltage of the energy storage module. This makes it easier to regulate the output power of the photovoltaic array by controlling the output voltage of the DC / DC converter.

[0146] Referring to Figure 8, in some embodiments, the photovoltaic array 111 includes a positive terminal and a negative terminal, the input interface of the DC / DC converter 112 includes a first input terminal and a second input terminal, and the output interface of the DC / DC converter 112 includes a first output terminal and a second output terminal; the photovoltaic array 112 is connected in series with the input interface of the DC / DC converter 112, including: the first output terminal of the DC / DC converter 112 is electrically connected to the positive terminal of the photovoltaic array 111; and the negative terminal of the photovoltaic array 111 is electrically connected to the first input terminal of the DC / DC converter 112.

[0147] In actual implementation, the first input terminal and the first output terminal of 112 can be electrically connected through the photovoltaic array 111 to form a feedforward path, i.e., the first power supply loop. The positive terminal of the photovoltaic array 111 is electrically connected to the first output terminal of the DC / DC converter 112, and the negative terminal of the photovoltaic array 111 is electrically connected to the first input terminal of the DC / DC converter 112.

[0148] According to Kirchhoff's laws, the following voltage-current relationship can be obtained:

[0149] U bat =U2+U pv ;

[0150] U1=U bat ;

[0151] I1+I pv =I out ;

[0152] I2=I pv .

[0153] The output power of the controlled device photovoltaic array 111 is:

[0154] P pv =U pv ×I pv .

[0155] The power consumed by DC / DC converter 112 is:

[0156] P = U² × I² = (U bat -U pv )×(- pv)=U pv ×I pv -U bat ×I pv

[0157] Comparison yields:

[0158] P < P pv .

[0159] Therefore, only a small portion of the total output power of the photovoltaic array 111 flows through the DC / DC converter 112, while the remaining main photovoltaic power is directly output through the feedforward path. This design optimizes a range of aspects of the DC / DC converter 112, including efficiency, power density, cost, and heat dissipation.

[0160] In the above formula, U1 and I1 represent the output voltage and output current of DC / DC converter 112, respectively; U2 and I2 represent the input voltage and input current of DC / DC converter 112, respectively; U pv and I pv These represent the output voltage and output current of photovoltaic array 111, respectively; U bat Indicates the voltage of energy storage module 120; I out This represents the sum of the current in the feedforward path and the output current of the DC / DC converter 112.

[0161] In some embodiments, the first output terminal and the second output terminal of the DC / DC converter 112 can also be electrically connected through an output capacitor C1; the first input terminal and the second input terminal of the DC / DC converter 112 can be electrically connected through an input capacitor C2; the first output terminal of the DC / DC converter 112 and the positive terminal of the energy storage module 120 can also be electrically connected through a filter inductor L.

[0162] In some embodiments, based on FIG8, FIG9 shows a further refined structure of the optical-storage coupling module.

[0163] According to the photovoltaic-storage coupling module provided in the embodiments of this application, the photovoltaic array is connected in series with the output terminal of the DC / DC converter, and the photovoltaic array and the DC / DC converter are connected in parallel with the energy storage module. The DC / DC converter in this photovoltaic-storage coupling module is a series boost partial power converter. The DC / DC converter only processes part of the output power of the photovoltaic array, not all of it. The power electronic devices and other electrical devices in the DC / DC converter do not need to withstand the maximum voltage of the submodule, which can reduce the power processing requirements of the DC / DC converter. The current carrying capacity requirements of each electrical device and power electronic device in the DC / DC converter are low, thereby improving the application range of the photovoltaic-storage coupling module. It can also reduce the size of each electrical device and power electronic device in the DC / DC converter, thereby reducing the overall size of the DC / DC converter and submodule. Furthermore, since it is not necessary to use electrical devices and power electronic devices with high current carrying capacity, it can reduce costs to a certain extent.

[0164] In some embodiments, the output current of the photovoltaic array 111 and the sum / difference of the input / output current of the DC / DC converter 112 are clamped by the current of the energy storage module 120.

[0165] In actual implementation, in some embodiments, the target electrical quantity can be current. The output current I of the photovoltaic array 111. pv The sum of the output current I1 of the DC / DC converter 112 and the current I of the energy storage module 120 bat Clamping satisfies the following formula:

[0166] I1+I pv =I bat .

[0167] In some embodiments, the target electrical quantity can be current. The output current I of the photovoltaic array 111 pv The difference between the input current I2 of the DC / DC converter 112 and the current I of the energy storage module 120 is... bat Clamping satisfies the following formula:

[0168] I bat +I2=I pv .

[0169] In some embodiments, the target electrical quantity can be current. The output current I of the photovoltaic array 111 pv The difference between the output current I1 of the DC / DC converter 112 and the current I of the energy storage module 120 is... bat Clamping, satisfying the following formula: I bat +I1=I pv .

[0170] In some embodiments, the target electrical quantity can be current. The output current I of the photovoltaic array 111 pv The sum of the input current I2 of the DC / DC converter 112 and the current I of the energy storage module 120 is bat Clamping satisfies the following formula:

[0171] I2+I pv =I bat .

[0172] According to the photovoltaic-storage coupling module provided in the embodiments of this application, the output current of the photovoltaic array is clamped by the output current of the energy storage module, and the sum / difference of the output / input current of the DC / DC converter is fixed by using the current of the energy storage module as a constant value, thereby fixing the relationship between the output current of the photovoltaic array and the output / input current of the DC / DC converter, and realizing the regulation of the photovoltaic array by controlling the output voltage of the DC / DC converter.

[0173] In some embodiments, the photovoltaic-storage coupling module further includes a controller, and the DC / DC converter 112 further includes a control terminal; the controller is connected to the control terminal of the DC / DC converter 112; the controller is used to control the output voltage and / or current of the DC / DC converter 112 to perform maximum power point tracking control on the photovoltaic array 111.

[0174] In actual implementation, the optical-storage coupling module may also include a controller for controlling the DC / DC converter 112.

[0175] In some embodiments, the DC / DC converter 112 may include a control terminal. In some embodiments, the control terminal may include the control electrode of each switch on the input side of the DC / DC converter 112. For example, for the structure shown in Figures 7 and 9, the control electrode of the switch is the gate of the IGBT, and the control terminal may include the gates of the four IGBTs on the input side of the DC / DC converter 112.

[0176] In actual operation, the controller can control the output voltage and / or output current of the DC / DC converter 112. Since the sum or difference between the output voltage of the photovoltaic array and the output voltage of the DC / DC converter 112 is clamped by the voltage of the energy storage module 120, and / or the sum or difference between the output current of the photovoltaic array and the output current of the DC / DC converter 112 is clamped by the current of the energy storage module 120, the output voltage / output current of the photovoltaic array 111 can be adjusted by controlling the output voltage and / or output current of the DC / DC converter 112. By controlling the output voltage and / or output current of the DC / DC converter 112 with the goal of tracking the maximum power point of the photovoltaic array 111, maximum power point tracking control of the photovoltaic array 111 can be achieved.

[0177] According to the photovoltaic-storage coupling module provided in the embodiments of this application, the output voltage and / or current of the DC / DC converter is controlled by the controller to perform maximum power point tracking control on the photovoltaic array. It can realize maximum power point tracking (MPPT) control of the photovoltaic array output by controlling the DC / DC converter, without the need to add an additional optimizer for photovoltaic MPPT control.

[0178] In some embodiments, a voltage regulator 113 is connected between the input interfaces and / or the output interfaces of the DC / DC converter 112.

[0179] In actual implementation, a voltage regulator 113 can be provided between the first input terminal and the second input terminal of the DC / DC converter 112, that is, the first input terminal and the second input terminal of the DC / DC converter 112 can be connected through the voltage regulator 113.

[0180] In some embodiments, a voltage regulator 113 may be provided between the first output terminal and the second output terminal of the DC / DC converter 112, that is, the first output terminal and the second output terminal of the DC / DC converter 112 can be connected through the voltage regulator 113.

[0181] According to the embodiments of this application, the photovoltaic-storage coupling module is connected between the input and / or output interfaces of the DC / DC converter through a voltage regulator component, which can stabilize the input and / or output voltage of the DC / DC converter, thereby improving the operational stability of the photovoltaic-storage coupling module and improving the accuracy of controlling the photovoltaic array.

[0182] In some embodiments, the voltage regulator 113 includes a capacitor.

[0183] In actual implementation, referring to Figures 4 to 9, the voltage regulator component 113 may include a capacitor. The voltage regulator component 113 located at the input interface of the DC / DC converter 112 includes capacitor C2. The voltage regulator component 113 located at the input interface of the DC / DC converter 112 includes capacitor C1.

[0184] The photovoltaic-storage coupling module provided in the embodiments of this application connects the input and / or output interfaces of the DC / DC converter via capacitors, which can stabilize the input and / or output voltages of the DC / DC converter. The components used are simple, without adding extra complexity to the circuit, which can improve the operational stability of the photovoltaic-storage coupling module and improve the accuracy of controlling the photovoltaic array.

[0185] In some embodiments, the DC / DC converter 112 employs a dual active bridge structure.

[0186] In practical implementation, referring to Figures 7 and 9, the DC / DC converter 112 can adopt a dual active bridge structure. The input side of the DC / DC converter 112 can use an active bridge structure composed of four IGBTs or diodes, and the output side of the DC / DC converter 112 can also use an active bridge structure composed of four IGBTs or diodes, thus the DC / DC converter 112 adopts a dual active bridge structure. The DC / DC converter 112 using the dual active bridge structure is a DAB converter.

[0187] According to the photovoltaic-storage coupling module provided in the embodiments of this application, the DC / DC converter 112 adopts a phase-shifted full-bridge structure, which can realize the control of the photovoltaic array output without the need to add an additional optimizer to control the photovoltaic output.

[0188] In some embodiments, the DC / DC converter 112 is an isolated DC / DC converter.

[0189] In actual implementation, referring to Figures 7 and 9, the DC / DC converter 112 can be an isolated DC / DC converter or a non-isolated DC / DC converter. When the DC / DC converter 112 adopts a dual active bridge structure and is an isolated DC / DC converter, the DC / DC converter 112 is an isolated dual active bridge DC / DC converter.

[0190] Understandably, isolated DC / DC converters include transformers to achieve voltage isolation.

[0191] According to the optical-storage coupling module provided in the embodiments of this application, by adopting an isolated DC / DC converter, the insulation requirements for the input and output sides of the DC / DC converter can be reduced, thereby reducing the complexity of engineering implementation.

[0192] In some embodiments, the energy storage module 120 includes parallel energy storage cabinets; each energy storage cabinet is composed of multiple battery cells connected in series and parallel.

[0193] In actual implementation, the energy storage module 120 can use energy storage batteries and / or capacitors with large capacitance values.

[0194] In some embodiments, the energy storage module 120 in a single photovoltaic-energy storage coupling module may be composed of multiple energy storage cabinets connected in parallel, which are composed of cells (i.e., battery cells) connected in series and parallel.

[0195] According to the photovoltaic-storage coupling module provided in the embodiments of this application, by adopting an energy storage cabinet composed of multiple battery cells connected in series and parallel to form an energy storage module 120, the energy storage capacity is stronger and more stable.

[0196] In some embodiments, the power module 130 adopts a half-bridge structure or a full-bridge structure.

[0197] In actual implementation, the power module 130 in a single optical-storage coupling module can be a half-bridge structure or a full-bridge structure. The power module 130 in Figures 4 to 5, 7 and 9 is an example of a half-bridge structure, but those skilled in the art will understand that a full-bridge structure of module 130 may be used.

[0198] According to the embodiment of this application, the optical-storage coupling module adopts a half-bridge structure or a full-bridge structure in the power module 130, making the operation of the optical-storage coupling module more stable and efficient.

[0199] This application also provides a photovoltaic-energy storage coupling system. Referring to FIG10, the photovoltaic-energy storage coupling system 1000 includes at least one power module 130, which is connected to the photovoltaic-energy storage coupling module 100. The power module 130 and the photovoltaic array 111 form a second power supply path, and / or, the power module 130 and the energy storage module 120 form a third power supply path.

[0200] In actual implementation, the optical-storage coupling system 1000 may include at least one submodule (SM). At least one of the aforementioned at least one submodule may be an optical-storage coupling module. The optical-storage coupling module may be the optical-storage coupling module 100 provided in any of the foregoing embodiments of this application.

[0201] In some embodiments, the photoelectric-storage coupling system 1000 may further include a power module 130. The power module 130 is a module composed of power electronic devices arranged according to certain functions.

[0202] In some embodiments, the energy storage module 120 and the power module 130 can be connected to form a third power supply path.

[0203] In some embodiments, the power module 130 can be a power module from the related art. That is, the connection relationship between the energy storage module 120 and the power module 130 can also be the connection relationship between the energy storage module and the power module in the photovoltaic-energy storage coupling module in the related art, with the energy storage module 120 and the power module 130 connected in parallel.

[0204] In some embodiments, the power module 130 may also be connected to the photovoltaic array 111 to form a second power supply path. In some embodiments, the power module 130 may also be connected to the positive and / or negative terminals of the photovoltaic array 111.

[0205] According to the photovoltaic-storage coupling system provided in the embodiments of this application, by employing any of the aforementioned photovoltaic-storage coupling modules, the power processing requirements of the DC / DC converter can be reduced, and the current-carrying capacity requirements of the various electrical and power electronic devices in the DC / DC converter are lower, thereby expanding the application range of the photovoltaic-storage coupling module. Furthermore, the size of the various electrical and power electronic devices in the DC / DC converter can be reduced, thereby reducing the overall equipment size of the DC / DC converter, sub-modules, and modular multilevel converter system. Also, since it is not necessary to use electrical and power electronic devices with high current-carrying capacity, costs can be reduced to a certain extent. Moreover, compared to the method in related technologies where photovoltaic-storage systems require multiple stages of converters for power exchange, in the embodiments of this application, after coupling the DC / DC converter and the photovoltaic array, the DC power output from the photovoltaic array can be partially exchanged by the DC / DC converter and then stored by the energy storage module. This reduces the number of conversions between the photovoltaic power station and the energy storage power station, reduces system losses, and also reduces the losses of power electronic devices by processing only a portion of the power.

[0206] In some embodiments, the optical-storage coupling system is a DC-connected optical-storage system, a modular multilevel converter type optical-storage system, or a cascaded optical-storage system.

[0207] In practical implementation, the photovoltaic-storage coupling system employs modular multilevel technology, connecting one end of a power module to the photovoltaic-storage coupling module and cascading the other end to connect multiple photovoltaic-storage coupling modules in series: a DC-connected photovoltaic-storage system, a modular multilevel converter photovoltaic-storage system (MMC photovoltaic-storage system), or a cascaded photovoltaic-storage system (star topology). Figures 11 to 13 respectively illustrate the DC-connected photovoltaic-storage system, the modular multilevel converter photovoltaic-storage system, and the cascaded photovoltaic-storage system. SM#1 to SM#N in Figures 11 to 13 represent the Nth sub-modules, from the 1st to the Nth. Any one of these N sub-modules can be formed by connecting the photovoltaic-storage coupling module and a power module provided in any of the preceding embodiments of this application. For example, any power sub-module in Figure 12 can be formed by connecting the photovoltaic-storage coupling module and a power module provided in any of the preceding embodiments of this application.

[0208] It is understood that both MMC photovoltaic-storage systems and cascaded photovoltaic-storage systems are AC direct-connected photovoltaic-storage systems. An MMC photovoltaic-storage system may include an MMC converter valve and photovoltaic-storage coupling modules connected to each power module of the converter valve. A cascaded photovoltaic-storage system may include a cascaded converter valve and photovoltaic-storage coupling modules connected to each power module of the converter valve.

[0209] According to the optical-storage coupling system provided in the embodiments of this application, by adopting any of the aforementioned optical-storage coupling modules, the power processing requirements of the DC / DC converter can be reduced, and the current carrying capacity requirements of each electrical and power electronic device in the DC / DC converter are low, thereby increasing the application range of the optical-storage coupling module. It can also reduce the size of each electrical and power electronic device in the DC / DC converter, thereby reducing the overall size of the DC / DC converter, sub-modules and modular multilevel converter system. Furthermore, since it is not necessary to use electrical and power electronic devices with high current carrying capacity, the cost can be reduced to a certain extent.

[0210] Furthermore, the modular multilevel converter type photovoltaic energy storage system, by adopting any of the aforementioned photovoltaic energy storage coupling modules and utilizing the cascading of power modules, is equivalent to connecting the power modules in series, which can increase the voltage of the photovoltaic energy storage system and thus increase the photovoltaic energy storage capacity.

[0211] Furthermore, DC direct-connected photovoltaic-storage systems using any of the aforementioned photovoltaic-storage coupling modules can be applied to scenarios such as DC power transmission and distribution networks, overcoming the AC harmonic problems present in the aforementioned scenarios in related technologies, and are more friendly to batteries and photovoltaic-storage systems.

[0212] Furthermore, AC direct-connected photovoltaic-storage systems using any of the aforementioned photovoltaic-storage coupling modules can be directly connected to the AC power grid, offering more application scenarios and better adaptability.

[0213] This application also provides a control method for an optical-storage coupling module. Referring to FIG14, the control method includes steps 1410 and 1420.

[0214] In practical implementation, this control method can be used to control the photovoltaic-storage coupling module provided in any of the foregoing embodiments of this application. It should be noted that the DC / DC converter 112 in the photovoltaic-storage coupling module provided in any of the foregoing embodiments of this application is a series boost partial power converter. In addition to the traditional buck-boost conversion function, the DC / DC converter 112 can also realize MPPT control of the output of the photovoltaic array 111 without the need to add an additional optimizer for MPPT control of the output of the photovoltaic array 111.

[0215] Step 1410: Obtain the maximum power point of the photovoltaic array at the target time.

[0216] In actual implementation, any conventional method can be used to obtain the maximum power point of the photovoltaic array 111 at the target time. For example, the above methods may include the perturbation observation method, the incremental conductance method, or the constant voltage method. The specific method used to obtain the maximum power point is not limited in the embodiments of this application.

[0217] It is understandable that the target time can be any sampling time.

[0218] Step 1420: Based on the maximum power point of the photovoltaic array at the target time, control the output voltage of the DC / DC converter to perform maximum power point tracking control on the photovoltaic array.

[0219] In actual implementation, the output voltage of the DC / DC converter 112 can be controlled based on the maximum power point of the photovoltaic array 111 at the target time, so that the photovoltaic array 111 operates at the maximum power point, thereby improving the overall efficiency of the photovoltaic array 111.

[0220] According to the control method of the photovoltaic-storage coupling module provided in the embodiments of this application, the output voltage U of the photovoltaic array is controlled by adjusting the output voltage of the DC / DC converter 112. pv The adjustment ultimately achieves MPPT control of the photovoltaic array 111. The photovoltaic array 111 can be MPPT controlled through the DC / DC converter 112 without the need for an additional optimizer, which can reduce costs to a certain extent.

[0221] In some embodiments, obtaining the maximum power point of the photovoltaic array at a target time includes: obtaining the output voltage and output current of the photovoltaic array 111 at the target time.

[0222] In actual execution, the output voltage U of the photovoltaic array 111 at each sampling moment can be obtained. pv and output current I pv Any sampling time can be used as the target time.

[0223] Based on the output voltage and output current of photovoltaic array 111 at the target time, the maximum power point of photovoltaic array 111 at the target time is obtained.

[0224] In actual implementation, any MPPT method can be used, based on the target voltage U at the target time of the photovoltaic array 111. pv_mppt and target current I pv_mppt The maximum power point of photovoltaic array 111 at the target time is obtained.

[0225] According to the control method of the photovoltaic-storage coupling module provided in the embodiments of this application, the maximum power point of the photovoltaic array at the target time can be obtained based on the output voltage and output current of the photovoltaic array at the target time. This allows for faster and more accurate acquisition of the maximum power point of the photovoltaic array at the target time, thereby enabling faster and more accurate MPPT control of the photovoltaic array.

[0226] In some embodiments, controlling the output voltage of the DC / DC converter based on the maximum power point of the photovoltaic array at a target time includes: obtaining a reference output voltage of the DC / DC converter 112 based on the maximum power point of the photovoltaic array 111 at the target time.

[0227] In actual execution, after obtaining the maximum power point of the photovoltaic array 111 at the target time, the reference output voltage of the DC / DC converter 112 is obtained according to any MPPT method.

[0228] The output voltage of the DC / DC converter 112 is controlled based on the reference voltage.

[0229] In actual operation, the reference output voltage U of the DC / DC converter 112 can be used. c_ref To achieve the control objective, the output voltage of the DC / DC converter 112 is controlled using any control method to realize MPPT control of the photovoltaic array 111.

[0230] In this embodiment, the control method used to control the output voltage of the DC / DC converter 112 based on the reference output voltage is not specifically limited. For example, it can be at least one or any combination of PI (Proportional-Integral) control, P control, PIR (Proportional-Integral-Resonant) control, D (Derivative) control, and PR control. "Multiple" here refers to more than two methods.

[0231] In actual implementation, the output voltage of the DC / DC converter 112 can be controlled based on the maximum power point of the photovoltaic array 111 at the target time, thereby controlling the output power of the photovoltaic array 111 to perform maximum power point tracking control on the photovoltaic array 111, thus realizing MPPT control of the photovoltaic array 111.

[0232] It should be noted that the control of the output voltage of the DC / DC converter 112 is based on the maximum power point of the photovoltaic array 111 at the target time. Therefore, the control of the output voltage of the DC / DC converter 112 can realize the MPPT control of the photovoltaic array 111.

[0233] For example, in the structure shown in Figures 6 and 7, due to the output voltage U1 or U of the DC / DC converter 112 c As an adjustable voltage source and the output voltage U of the photovoltaic array pv Connected in series, and because of U c +U pv =U bat U cand U pv The sum of the voltage U of the energy storage module 120 bat Clamping, therefore, can be achieved by adjusting U c To achieve the output voltage U of the photovoltaic array pv The adjustment ultimately achieves MPPT control of the photovoltaic array 111. Similarly, for the structures shown in Figures 10 and 9, the input voltages U2 and U of the DC / DC converter 112 are... pv The sum of the voltage U of the energy storage module 120 bat Clamping, the output voltage U1 or U of DC / DC converter 112 c There is a proportional relationship between it and the input voltage U2, so it can also be adjusted by U c To achieve the output voltage U of the photovoltaic array pv The adjustment ultimately achieves MPPT control of the photovoltaic array 111.

[0234] According to the control method of the photovoltaic-storage coupling module provided in the embodiments of this application, the output voltage U of the photovoltaic array is controlled by adjusting the output voltage of the DC / DC converter 112. pv The adjustment ultimately achieves MPPT control of the photovoltaic array 111. The photovoltaic array 111 can be MPPT controlled through the DC / DC converter 112 without the need for an additional optimizer, which can reduce costs to a certain extent.

[0235] In some embodiments, obtaining the reference output voltage of the DC / DC converter 112 based on the maximum power point of the photovoltaic array 111 at the target time includes: obtaining the target voltage corresponding to the maximum power point of the photovoltaic array 111 at the target time based on the maximum power point of the photovoltaic array 111 at the target time, and obtaining the voltage of the energy storage module 120.

[0236] In actual execution, after obtaining the maximum power point of photovoltaic array 111 at the target time, the target voltage U corresponding to the maximum power point of photovoltaic array 111 at the target time is obtained according to any MPPT method. pv_mppt By sampling or measuring the voltage of the energy storage module 120, the voltage U of the energy storage module 120 can be obtained. bat .

[0237] The reference output voltage is obtained based on the target voltage and the voltage of the energy storage module 120.

[0238] In actual execution, it can be based on the target voltage and target current, as well as U. c +U pv =U bat Obtain the reference output voltage U of DC / DC converter 112 c_ref Uc_ref =U bat -U pv_mppt .

[0239] In some embodiments, referring to FIG15, the control of the optical-storage coupling module shown in FIG7 may include the following steps.

[0240] In this photovoltaic-storage coupling module, the two IGBTs connected adjacent to the photovoltaic array 111 and input capacitor on the input side of the DC / DC converter 112 are controlled with a duty cycle of 0.5. Through PWM (Pulse Width Modulation) control, the two IGBTs are output as on / off signals. Specifically, when the upper IGBT is on, the lower IGBT is off; conversely, when the lower IGBT is on, the upper IGBT is off.

[0241] The control process for two IGBTs connected adjacent to the isolation transformer in the DC / DC converter 112 may include the following steps.

[0242] Step 1: Input U at each moment into the MPPT controller pv and I pv The maximum power point U at each time step is obtained using the MPPT algorithm (the specific MPPT algorithm is not limited). pv_mppt and I pv_mppt ;

[0243] Step 2: Calculate U c_ref =U bat -U pv The reference output voltage U of the DC / DC converter 112 at each moment is obtained. c_ref ;

[0244] Step 3: Set U at each moment c_ref With U at every moment C The difference is processed by PI control to satisfy U. C Infinitely close to or equal to U C_ref To meet the control requirements, the output result is converted into the phase angle difference between the two IGBTs connected to the isolation transformer and the two IGBTs connected to the photovoltaic array 111 and the input capacitor.

[0245] Step 4: Add the phase angle difference to the turn-on / turn-off signals of the two IGBTs connected to the photovoltaic array 111 and the input capacitor to obtain the turn-on / turn-off signals of the two IGBTs connected to the isolation transformer. Specifically, when the upper IGBT is on, the lower IGBT is off; conversely, when the lower IGBT is on, the upper IGBT is off.

[0246] According to the control method of the photovoltaic-storage coupling module provided in the embodiments of this application, the reference output voltage of the DC / DC converter 112 is obtained based on the target voltage corresponding to the maximum power point of the photovoltaic array 111 at the target time and the voltage of the energy storage module. Using the reference output voltage of the DC / DC converter 112 as the control target, the output voltage of the DC / DC converter 112 is adjusted to achieve control over the output voltage U of the photovoltaic array. pv The adjustment ultimately achieves MPPT control of the photovoltaic array 111. The photovoltaic array 111 can be MPPT controlled through the DC / DC converter 112 without the need for an additional optimizer, which can reduce costs to a certain extent.

[0247] 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.

[0248] 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.

[0249] 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.

[0250] 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.

[0251] 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.

[0252] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0253] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A photoelectric energy storage coupling module, comprising: A photovoltaic power generation module and an energy storage module are provided. The photovoltaic power generation module includes a photovoltaic array and a DC / DC converter. The DC / DC converter includes an input interface and an output interface. The photovoltaic array is connected to the input interface, and the energy storage module is connected to the output interface to form a first power supply path. The photovoltaic array is connected in series with the input interface or the output interface of the DC / DC converter. The photovoltaic power generation module and the energy storage module are connected in parallel to form a first power supply loop.

2. The optical-storage coupling module according to claim 1, wherein, The sum / difference between the target electrical quantity output by the photovoltaic array and the target electrical quantity input / output by the DC / DC converter is clamped by the target electrical quantity of the energy storage module.

3. The optical-storage coupling module according to claim 2, wherein, The sum of the output voltage of the photovoltaic array and the output voltage of the DC / DC converter is clamped by the voltage of the energy storage module.

4. The optical-storage coupling module according to claim 3, wherein, The photovoltaic array includes a positive terminal and a negative terminal; the input interface of the DC / DC converter includes a first input terminal and a second input terminal; and the output interface of the DC / DC converter includes a first output terminal and a second output terminal. The photovoltaic array is connected in series with the output interface of the DC / DC converter, including: The positive terminal is electrically connected to the first input terminal and the second output terminal of the DC / DC converter.

5. The optical-storage coupling module according to claim 2, wherein, The sum of the output voltage of the photovoltaic array and the input voltage of the DC / DC converter is clamped by the voltage of the energy storage module.

6. The optical-storage coupling module according to claim 5, wherein, The photovoltaic array includes a positive terminal and a negative terminal. The input interface of the DC / DC converter includes a first input terminal and a second input terminal. The output interface of the DC / DC converter includes a first output terminal and a second output terminal. The photovoltaic array is connected in series with the input interface of the DC / DC converter, including: the first output terminal of the DC / DC converter is electrically connected to the positive terminal of the photovoltaic array; the negative terminal of the photovoltaic array is electrically connected to the first input terminal of the DC / DC converter.

7. The optical-storage coupling module according to claim 2, wherein, The output current of the photovoltaic array and the sum / difference of the input / output current of the DC / DC converter are clamped by the current of the energy storage module.

8. The optical-storage coupling module according to any one of claims 1 to 7, wherein, The photovoltaic-storage coupling module further includes a controller, and the DC / DC converter further includes a control terminal; the controller is connected to the control terminal of the DC / DC converter; the controller is used to control the output voltage and / or current of the DC / DC converter to perform maximum power point tracking control on the photovoltaic array.

9. The optical-storage coupling module according to any one of claims 1 to 8, wherein, A voltage regulator is connected between the input interfaces and / or the output interfaces of the DC / DC converter.

10. The optical-storage coupling module according to claim 9, wherein, The voltage regulator component includes a capacitor.

11. The optical-storage coupling module according to claims 1 to 10, wherein, The DC / DC converter adopts a dual active bridge structure.

12. The optical-storage coupling module according to claim 11, wherein, The DC / DC converter is an isolated DC / DC converter.

13. A photoelectric-storage coupling system, wherein, It includes at least one power module, the power module being connected to the photovoltaic-storage coupling module as described in any one of claims 1 to 12, the power module forming a second power supply path with the photovoltaic array, and / or, the power module forming a third power supply path with the energy storage module.

14. The photoelectric storage coupling system according to claim 13, wherein, The photovoltaic-storage coupling system can be a DC-connected photovoltaic-storage system, a modular multilevel converter photovoltaic-storage system, or a cascaded photovoltaic-storage system.

15. A control method for an optical-storage coupling module as described in any one of claims 1 to 12, wherein, include: Obtain the maximum power point of the photovoltaic array at the target time; Based on the maximum power point of the photovoltaic array at the target time, the output voltage of the DC / DC converter is controlled to perform maximum power point tracking control on the photovoltaic array.

16. The control method for the optical-storage coupling module according to claim 15, wherein, The process of obtaining the maximum power point of the photovoltaic array at the target time includes: Obtain the output voltage and output current of the photovoltaic array at the target time; Based on the output voltage and output current of the photovoltaic array at the target time, the maximum power point of the photovoltaic array at the target time is obtained.

17. The control method for the optical-storage coupling module according to claim 15 or 16, wherein, The control of the output voltage of the DC / DC converter based on the maximum power point of the photovoltaic array at the target time includes: Based on the maximum power point of the photovoltaic array at the target time, obtain the reference output voltage of the DC / DC converter; The output voltage of the DC / DC converter is controlled based on the reference output voltage.

18. The control method for the optical-storage coupling module according to claim 17, wherein, The step of obtaining the reference output voltage of the DC / DC converter based on the maximum power point of the photovoltaic array at the target time includes: Based on the maximum power point of the photovoltaic array at the target time, obtain the target voltage corresponding to the maximum power point of the photovoltaic array at the target time, and obtain the voltage of the energy storage module; The reference output voltage is obtained based on the target voltage and the voltage of the energy storage module.

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