New-energy energy storage sub-module and operation method therefor, and energy storage system and operation method therefor

Abstract

A new-energy energy storage sub-module and an operation method therefor, and an energy storage valve and an energy storage system comprising an energy storage valve and an operation method for the energy storage system.comprising the energy storage valve and an operation method of the energy storage system In a new-energy grid-connected system, new-energy assemblies are arranged in sub-modules in a distributed mode, such that a new-energy energy storage sub-module comprising a direct-current bus, a power module, an energy storage module, a first converter and a new-energy assembly is built, and the new-energy assembly is accessed as the new-energy energy storage sub-module to an energy storage system for operation. By means of modularizing new-energy assemblies, the impact of an individual fault of the new-energy assemblies on a new-energy grid-connected system can be reduced, that is, when a single new-energy assembly has a fault, a new-energy energy storage sub-module where the faulty new-energy assembly is located is removed, thereby reducing the impact on the operation of other new-energy assemblies, and increasing the operation time proportion of the new-energy grid-connected system, thus effectively improving the system availability of the new-energy grid-connected system.

Description

New energy storage submodule and operation method thereof, energy storage system and operation method thereof Cross-references

[0001] This application refers to Chinese patent application No. 202311526165.8 filed on November 15, 2023, entitled “New energy storage sub-module and its operation method, energy storage system and its operation method”, which is incorporated into this application in its entirety by reference. Technical Field

[0002] The present application relates to the field of energy storage technology, and in particular to a new energy storage submodule and an operating method thereof, an energy storage valve, an energy storage system and an operating method thereof. Background Art

[0003] With the development of new energy and energy storage technologies, the grid-connected operation of new energy power generation modules and energy storage systems has gradually gained momentum. Renewable energy generation has gained widespread application due to its clean, pollution-free operation, short construction period, long service life, and low maintenance costs. New energy grid-connected systems typically use inverters to convert the DC power output of new energy components into AC power, which is then boosted to grid voltage by transformers for transmission to the AC grid.

[0004] However, in the related art, when a new energy component fails, the new energy grid-connected system will be shut down, resulting in low system availability of the new energy grid-connected system.

[0005] Based on this, it is necessary to provide a new energy storage submodule and its operating method, an energy storage valve, an energy storage system and its operating method to improve the system availability of the new energy grid-connected system.

[0006] The new energy storage submodule provided in the embodiment of the present application includes a DC bus, a power module, an energy storage module, a first converter and a new energy component. The power module includes a grid connection side and a DC side. The grid connection side of the power module is used to cascade with adjacent new energy storage submodules. The energy storage module is connected to the DC side of the power module through a DC bus. The first converter is connected to the DC bus, and the new energy component is connected to the first converter.

[0007] In the above scheme, in the new energy grid-connected system, the new energy components are distributedly arranged in each sub-module to form a new energy storage sub-module including a DC bus, a power module, an energy storage module, a first converter and new energy components. The new energy components are connected to the energy storage system in the form of new energy storage sub-modules for operation. Through this scheme, the new energy components are distributedly arranged in each new energy storage sub-module, and the new energy components are modularized, which has better flexibility and can reduce the impact of single failures of new energy components on the new energy grid-connected system. That is, when a single new energy component fails, the new energy storage sub-module where the failed new energy component is located can be removed, reducing the impact on the operation of other new energy components and increasing the proportion of operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0008] In some embodiments, the new energy storage submodule further includes a second converter, which is disposed between the DC bus and the energy storage module and is connected to the DC bus and the energy storage module respectively.

[0009] In the above solution, a second converter is further provided between the DC bus and the energy storage module. The second converter can realize DC voltage conversion during the charging and discharging process to meet the charging and discharging requirements of the energy storage module.

[0010] In some embodiments, the second converter includes a bidirectional non-isolated DC converter or a bidirectional isolated DC converter.

[0011] In the above solution, the second converter can be configured as a bidirectional non-isolated DC converter or a bidirectional isolated DC converter, which can be selected based on the actual scenario, and has high configuration flexibility.

[0012] In some embodiments, the new energy storage submodule further includes an insulating support assembly, and the new energy assembly is disposed on the insulating support assembly.

[0013] In the above solution, the new energy components are arranged on the insulating support components, and voltage isolation is performed through the insulating support components to improve the operational reliability of the new energy components.

[0014] In some embodiments, the first converter comprises a non-isolated DC converter.

[0015] In the above solution, when the new energy component is voltage-isolated by the insulating support component, the first converter between the new energy component and the DC bus directly adopts a non-isolated DC converter, which can effectively reduce costs.

[0016] In some embodiments, the first converter comprises an isolated DC converter.

[0017] In the above solution, the first converter between the new energy component and the DC bus adopts an isolated DC converter. The high-voltage isolation of the new energy component can be achieved through the isolated converter, so that the new energy component can be set up without going through an insulating support component, thereby improving the convenience of setting up the new energy storage sub-module.

[0018] In some embodiments, the new energy storage submodule further includes a third converter, which is disposed between the DC bus and the power module and is connected to the DC bus and the DC side of the power module respectively.

[0019] In the above solution, the energy storage module is connected to the third converter via a DC bus, so that the new energy component is directly connected between the third converter and the energy storage module. The electric energy generated by the new energy component can be transmitted to the energy storage module without passing through the third converter, which can effectively improve the efficiency of electric energy transmission.

[0020] In some embodiments, the new energy component comprises a photovoltaic component.

[0021] In the above solution, the new energy components specifically adopt photovoltaic components, and the power generation and operation stability of the new energy storage sub-module are guaranteed.

[0022] An embodiment of the present application also provides an operating method based on the above-mentioned new energy energy storage sub-module, including: when the electric energy storage conditions are met, the electric energy output by the new energy component is converted by the first converter and then transmitted to the energy storage module for storage; when the electric energy supply conditions are met, the electric energy output by the new energy component is converted by the first converter and the power module and then transmitted to the power grid for load power supply.

[0023] In the above scheme, the electric energy generated by the new energy components can be transmitted to the energy storage module for storage according to actual conditions, and / or transmitted to the power grid to power the load, thereby reducing the waste of electric energy generated by the new energy components and improving the electric energy utilization rate of the new energy components.

[0024] In some embodiments, the operating method of the new energy storage sub-module also includes: obtaining the output electrical parameters of the new energy component; determining the target output voltage when the new energy component operates at maximum power based on the output electrical parameters; and controlling the operation of the first converter based on the output electrical parameters and the target output voltage.

[0025] The above solution can be combined with the output electrical parameters of the new energy components to maintain the new energy components running at maximum power and improve the operating efficiency of the new energy components.

[0026] In some embodiments, the output electrical parameters include output voltage and output current. Based on the output electrical parameters, the target output voltage of the new energy component when it operates at maximum power is determined, including: performing maximum power point tracking control based on the output voltage and output current to determine the target output voltage of the new energy component when it operates at maximum power; and controlling the operation of the first converter based on the output electrical parameters and the target output voltage, including: controlling the operation of the first converter based on the output voltage and the target output voltage.

[0027] The above scheme can combine the output current and output voltage of the new energy component to perform maximum power point tracking control, thereby determining the target output voltage when the new energy component is running at maximum power, and improving the control accuracy of the new energy component running at maximum power.

[0028] In some embodiments, the operation of the first converter is controlled according to the output voltage and the target output voltage, including: determining the output voltage difference according to the comparison between the output voltage and the target output voltage; performing proportional-integral adjustment according to the output voltage difference to determine the first target duty cycle; performing pulse width modulation according to the first target duty cycle to generate a first switching signal and send it to the first converter.

[0029] The above scheme combines the output voltage and the target output voltage to perform proportional-integral regulation, and performs pulse width modulation on the result of the proportional-integral regulation, thereby determining the first switching signal required for the operation of the first converter, and performing on-off control on the first converter, thereby realizing the operation control of the first converter with high control accuracy.

[0030] In some embodiments, the operation method of the new energy storage submodule further includes: obtaining a DC bus voltage reference value and a DC bus voltage; and performing voltage stabilization control on the DC bus according to the DC bus voltage reference value and the DC bus voltage.

[0031] The above solution can also be combined with the DC bus voltage and the DC bus voltage reference value to achieve voltage stabilization control of the DC bus, effectively improving the operational reliability of the new energy storage sub-module.

[0032] In some embodiments, the DC bus is voltage-stabilized and controlled based on the DC bus voltage reference value and the DC bus voltage, including: determining a bus voltage difference based on the DC bus voltage reference value and the DC bus voltage; performing proportional-integral adjustment based on the bus voltage difference to determine a second target duty cycle; performing pulse width modulation based on the second target duty cycle to generate a second switching signal and send it to the second converter.

[0033] The above scheme combines the bus voltage difference between the DC bus voltage reference value and the DC bus voltage, performs proportional-integral regulation and pulse width modulation in sequence, and finally generates a second switching signal to control the operation of the second converter. That is, DC bus voltage stabilization control is achieved through the second converter, which has the advantage of high voltage stabilization control accuracy.

[0034] An embodiment of the present application further provides an energy storage valve, comprising a submodule controller and the above-mentioned new energy storage submodule, wherein the new energy storage submodules are cascaded and each new energy storage submodule is respectively connected to the submodule controller.

[0035] An embodiment of the present application also provides an energy storage system, including a converter valve and the above-mentioned energy storage valve, wherein the first end and the second end formed by cascading each new energy storage submodule are respectively connected to the converter valve, and the converter valve is used to connect to the AC power grid.

[0036] In some embodiments, the converter valve includes at least one of a voltage source converter valve, a grid commutated converter valve, and a cascade converter valve.

[0037] An embodiment of the present application also provides an operating method based on the above-mentioned energy storage system, including: when the new energy component has output, obtaining the new energy output power of the new energy component and the system demand power of the AC power grid; controlling the new energy component to output electric energy according to the new energy output power and the system demand power.

[0038] The operating method of the above-mentioned energy storage system combines the new energy output power of the new energy components with the system power demand of the AC power grid to realize the output power control of the new energy components, smooth the power output of the power grid, realize the high integration of new energy power generation and energy storage, and improve the grid-connected operation reliability of the energy storage system.

[0039] In some embodiments, the output of electric energy by the new energy component is controlled according to the new energy output power and the system required power, including: when the new energy output power is greater than the system required power, controlling the new energy component to output electric energy to the AC power grid and the energy storage module; when the new energy output power is equal to the system required power, controlling the new energy component to output electric energy to the AC power grid; when the new energy output power is less than the system required power, controlling the new energy component and the energy storage module to output electric energy to the AC power grid at the same time.

[0040] The above solution controls the transmission of new energy components and the charging and discharging of energy storage modules based on the relationship between the output power of new energy and the power required by the system, effectively improving the operating efficiency of the energy storage system.

[0041] In some embodiments, the operating method of the energy storage system further includes: controlling the energy storage module to output electrical energy to the AC power grid when the new energy component does not output.

[0042] In the above solution, when there is no output from the new energy component, the energy storage module is used to supply power to the AC grid to meet the load demand of the AC grid and improve the functional reliability of the energy storage system for the AC grid.

[0043] In some embodiments, the operating method of the energy storage system further includes: when the new energy storage submodule is bypassed, disconnecting the power transmission between the new energy component and the energy storage module.

[0044] The above solution interrupts the transmission of power from the new energy component to the energy storage module when the new energy storage submodule is bypassed, thereby improving the operational safety of the energy storage module.

[0045] In some embodiments, the operation method of the energy storage system further includes: when the energy storage module is fully charged, disconnecting the power transmission between the new energy component and the energy storage module; when the energy storage module is discharged to a preset power threshold, connecting the power transmission between the new energy component and the energy storage module.

[0046] The above solution interrupts the transmission of power from the new energy component to the energy storage module when the energy storage module is fully charged, thereby preventing the energy storage module from overcharging and improving the charging safety of the energy storage module. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on the drawings without inventive work. In the drawings:

[0048] FIG1 is a schematic diagram of an application scenario of a new energy storage submodule in some embodiments of the present application;

[0049] FIG2 is a schematic diagram of the structure of a converter valve in some embodiments of the present application;

[0050] FIG3 is a schematic diagram of the structure of a converter valve in some other embodiments of the present application;

[0051] FIG4 is a schematic diagram of the structure of a new energy storage submodule in some embodiments of the present application;

[0052] FIG5 is a schematic diagram of the structure of a new energy storage submodule in some other embodiments of the present application;

[0053] FIG6 is a schematic diagram of the structure of a new energy storage submodule in some other embodiments of the present application;

[0054] FIG7 is a schematic diagram of the structure of a new energy storage submodule in some further embodiments of the present application;

[0055] FIG8 is a schematic diagram of the structure of a new energy storage submodule in some other embodiments of the present application;

[0056] FIG9 is a schematic diagram of the structure of a new energy storage submodule in some further embodiments of the present application;

[0057] FIG10 is a schematic flow chart of an operating method of a new energy storage submodule in some embodiments of the present application;

[0058] FIG11 is a schematic diagram of a control flow of a first converter in some embodiments of the present application;

[0059] FIG12 is a schematic flow chart of an operating method of a new energy storage submodule in other embodiments of the present application;

[0060] FIG13 is a schematic diagram of a second converter control flow in some embodiments of the present application;

[0061] FIG14 is a flow chart of an operating method of an energy storage system in some embodiments of the present invention. DETAILED DESCRIPTION

[0062] The following will describe in detail the embodiments of the technical solution of the present application in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only used as examples and cannot be used to limit the scope of protection of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" in the specification and claims of the present application and the above-mentioned description of the drawings and any variations thereof are intended to cover non-exclusive inclusions.

[0063] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0064] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0065] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0066] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0067] Currently, judging by market developments, new energy sources are gradually replacing traditional fossil fuels and occupying a significant position in the energy supply sector. Among various types of renewable energy, renewable energy power generation is widely used due to its stable and reliable operation, simple operation and maintenance, low maintenance costs, and long service life. Renewable energy power generation is generally integrated into the AC grid and energy storage systems. After renewable energy components convert solar energy (photovoltaics, for example) into DC power, the energy can be directly transmitted to the energy storage system for storage or converted and boosted by renewable energy inverters and transformers before being transmitted to the AC grid. The voltage level of renewable energy inverters is generally below 1 kV (kilovolts). With the application of multi-level technology in renewable energy grid-connected systems, the voltage level of renewable energy inverters can even reach 35 kV.

[0068] However, in a grid-connected renewable energy system where renewable energy components and energy storage systems operate in parallel, solar curtailment and unstable power quality are inevitable due to component failures. In particular, in scenarios where renewable energy components are connected in series and / or parallel to form a renewable energy array, a single component failure can affect the operation of the entire renewable energy array and, in severe cases, even cause the grid-connected renewable energy system to shut down, resulting in low system availability.

[0069] To alleviate the low system availability of renewable energy grid-connected systems, research has found that centralized renewable energy components can be distributed within energy storage systems. This distributed configuration reduces the impact of single component failures on the renewable energy grid-connected system, thereby improving the system availability.

[0070] Based on these considerations, and to achieve a distributed configuration of new energy components, in-depth research led to the design of a new energy storage submodule integrated with new energy components. Specifically, the submodule comprises a DC bus, power module, energy storage module, converter, and new energy components. The new energy components are connected to the energy storage system as a new energy storage submodule, enabling grid-connected operation of the new energy generation and storage system.

[0071] Through the above method, the new energy components are distributedly set in each new energy energy storage sub-module, and the new energy components are modularized, which has good flexibility and can reduce the impact of single failure of new energy components on the new energy grid-connected system. That is, when a single new energy component fails, the new energy storage sub-module where the failed new energy component is located can be removed, reducing the impact on the operation of other new energy components and increasing the proportion of operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0072] The new energy storage submodule provided in the embodiment of the present application is applied to an energy storage system. After the energy storage system is connected to the AC power grid, a new energy grid-connected system can be constructed. Specifically, the energy storage system can be a DC direct-connected type energy storage system. Please refer to Figure 1. In this energy storage system, each new energy storage submodule 11 is cascaded in sequence, and the structure formed after the cascade is connected to the submodule controller (not shown) to jointly construct an energy storage valve 10. The energy storage valve 10 is connected to the converter valve 20, and the converter valve 20 is further connected to the AC power grid 30, ultimately obtaining a new energy grid-connected system.

[0073] It should be noted that the type of converter valve 20 in the above-mentioned energy storage system is not limited. As long as it is a device that can realize the rectification and inversion functions, it can be set according to actual needs. For example, in some embodiments, the converter valve 20 includes a line commutated converter (LCC) converter valve, a VSC (voltage sourced converter) converter valve, etc. In some embodiments, the VSC converter valve can also be two single-level converters, a three-level converter, or a modular multilevel converter (MMC) converter valve as shown in Figure 2, etc., without specific limitation. In another embodiment, the converter valve 20 can also adopt the cascade converter valve shown in Figure 3, and can be set according to actual needs.

[0074] Please refer to Figure 4. The new energy storage sub-module provided in the embodiment of the present application includes a DC bus 411, a power module 413, an energy storage module 415, a first converter 417 and a new energy component 419. The power module 413 includes a grid connection side and a DC side. The grid connection side of the power module 413 is used to cascade with adjacent new energy storage sub-modules. The energy storage module 415 is connected to the DC side of the power module 413 through the DC bus 411. The first converter 417 is connected to the DC bus 411, and the new energy component 419 is connected to the first converter 417.

[0075] The DC bus 411 is the line for transmitting DC power between the energy storage module 415 and the power module 413. The power module 413 is a device used to achieve power conversion; the energy storage module 415 is a device used to store electrical energy and release it when it is needed. The new energy component 419 is a device that can generate electricity through new energy generation. The first converter 417 is a device that can convert the electrical energy generated by the new energy component 419 into a DC power of appropriate magnitude and transmit it to the DC bus.

[0076] In the technical solution of the present application, the first converter 417 is connected to the DC bus 411. In some embodiments, the first converter 417 may be connected to the common connection point between the DC bus 411 and the power module 413. In this case, the first converter 417 can be equivalently considered to be connected to the DC side of the power module 413. In other embodiments, the first converter 417 may be connected to the middle section of the DC bus 411. In this case, the first converter 417 can be equivalently considered to be connected to the DC side of the power module 413 through the DC bus 411, and the first converter 417 can be connected to the energy storage module 415 through the DC bus 411. In other embodiments, the first converter 417 may be connected to the common connection point between the DC bus 411 and the energy storage module 415. In this case, the first converter 417 can be equivalently considered to be connected to the energy storage module 415.

[0077] It should be noted that the specific type of the new energy component 419 is not unique, and can be one or more of a photovoltaic component, a wind power generation component, a biomass power generation component, and a tidal power generation component. Correspondingly, the type of the first converter 417 will also be different. If the electric energy generated by the new energy component 419 is alternating current, the corresponding first converter 417 should adopt an alternating current / direct current converter (also known as an AC / DC converter). If the electric energy generated by the new energy component 419 is direct current, the corresponding first converter 417 should adopt a direct current converter (also known as a DC-DC converter). It should be noted that the DC bus 411 includes a first-end DC bus (a positive DC bus or a negative DC bus) and a second-end DC bus (with opposite polarity to the first-end DC bus). The energy storage module 415 is connected to the power module 413 via the DC bus 411, including the positive and negative poles of the energy storage module 415, which are connected to the two ends of the DC side of the power module 413 through the positive and negative DC buses, respectively. It should be noted that the first converter 417 is connected to the DC bus 411, and the new energy component 419 is connected to the first converter. The first converter 417 has at least three terminals, two of which are connected to the positive and negative DC busbars, respectively, and at least one of which is connected to the new energy component 419. To facilitate understanding of the technical solution of this application, the following embodiments are explained using the example of the new energy component 419 being a photovoltaic component to achieve photoelectric conversion, and the first converter 417 being a DC converter. This effectively improves the power generation and operational stability of the new energy storage submodule.

[0078] During normal operation of the new energy component 419, light energy is converted into electrical energy, which is transmitted in the form of DC power. After DC conversion by the first converter 417, it is converted into DC power suitable for the energy storage module 415 and then transmitted to the energy storage module 415 for storage. The new energy component 419 can also be connected to a new energy inverter outside the new energy storage submodule. The DC power generated by the new energy component 419 is transmitted to the new energy inverter for conversion to AC power. This AC power is then stepped up by the subsequent transformer and transmitted to the AC grid for use.

[0079] In actual use scenarios, the new energy storage submodule only needs to choose to transmit DC power to the energy storage module 415 and / or the AC grid based on the system power demand of the AC grid and the amount of power stored in the energy storage module 415, thereby minimizing the occurrence of abandoned light from the new energy component 419. In this way, when the power generated by the new energy component 419 charges the energy storage module 415, it only needs to pass through the first converter 417 at a minimum, that is, only one level of conversion, before reaching the energy storage module 415, reducing losses, shortening delays, and greatly improving conversion efficiency.

[0080] It should be noted that the specific type of the power module 413 is not unique. It can be a full-bridge power module or a half-bridge power module. The bridge arm power electronic devices include at least one of IGBT (Insulate-Gate Bipolar Transistor), IEGT (Injection Enhanced Gate Transistor), and IGCT (Integrated Gate-Commutated Thyristor). The specific selection can be made in combination with actual needs. In some embodiments, taking the half-bridge power module as an example for explanation, please refer to Figure 5. The power module 413 includes a half-bridge power unit 510 and a parallel DC support capacitor C. Here, the power module 413 is used to control the input and removal of the new energy storage sub-module. In some embodiments, please continue to refer to Figure 5. The power module 413 also includes a voltage equalizing resistor R arranged in parallel with the DC support capacitor C, and / or also includes a bypass switch P arranged on the side of the half-bridge power unit away from the DC support capacitor C.

[0081] Similarly, the specific structure of the energy storage module 415 is not unique. In some embodiments, please refer to Figure 5. The energy storage module 415 includes an energy storage battery pack S and a charge-discharge circuit. One end of the energy storage battery pack S is connected to the DC bus 411 through the charge-discharge circuit, and the other end of the energy storage battery pack S is connected to the DC bus 411. The specific structure of the charge-discharge circuit is not unique. As shown in Figure 5, it may include a pre-charge resistor R1, a pre-charge switch K1, and a normal switch K2. The pre-charge resistor R1 and the pre-charge switch K1 are connected in series and then in parallel to the two ends of the normal switch K2, thereby forming a charge-discharge circuit. The energy storage battery pack S may include multiple lithium batteries, each of which is connected in series and / or in parallel to ultimately form the energy storage battery pack S.

[0082] In some embodiments, please refer to Figure 5. The new energy storage sub-module also includes an isolating switch K. The energy storage module 415 is connected to the power module 413 through the isolating switch K. By opening the isolating switch K, electrical isolation is achieved between the energy storage module 415 and the power module 413, thereby improving the operating safety of the new energy storage sub-module.

[0083] In the above solution, in the new energy grid-connected system, the new energy components 419 are distributedly arranged in each sub-module to form a new energy storage sub-module including a DC bus 411, a power module 413, an energy storage module 415, a first converter 417 and a new energy component 419. The new energy component 419 is connected to the energy storage system for operation in the form of a new energy storage sub-module. Through this solution, the new energy components 419 are distributedly arranged in each new energy storage sub-module, and the new energy components 419 are modularized, which has good flexibility and can reduce the impact of a single failure of the new energy component 419 on the new energy grid-connected system. That is, when a single new energy component 419 fails, the new energy storage sub-module where the failed new energy component is located can be removed, thereby reducing the impact on the operation of other new energy components 419 and increasing the proportion of the operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0084] Please refer to Figure 6. In some embodiments, the new energy storage submodule further includes a second converter 612. The second converter 612 is disposed between the DC bus 411 and the energy storage module 415 and is connected to the DC bus 411 and the energy storage module 415 respectively.

[0085] The second converter 612 is a converter that can transmit DC power in both directions. Specifically, in the embodiment of the present application, bidirectional transmission refers to the DC power output by the new energy component 419, which can be input into the energy storage module 415 through the second converter 612 to realize charging of the energy storage module 415; and can also output the electric energy stored in the energy storage module 415 through the second converter 612 to realize discharging of the energy storage module 415.

[0086] Moreover, through the setting of the second converter 612 in the embodiment of the present application, during the operation of the new energy storage sub-module, the operation of the switching device in the second converter 612 can be controlled in combination with the change of the DC bus voltage, so as to achieve the purpose of stabilizing the DC bus 411 and effectively improve the operating stability of the new energy storage sub-module.

[0087] In the above solution, a second converter 612 is further provided between the power module 413 and the energy storage module 415 . Through the second converter 612 , the energy storage module 415 can realize DC voltage conversion during charging and discharging to meet the charging and discharging requirements of the energy storage module 415 .

[0088] The specific type of the second converter 612 is not limited. In some embodiments, the second converter 612 includes a bidirectional non-isolated DC converter or a bidirectional isolated DC converter.

[0089] An isolated DC converter is a device that uses isolation components to achieve DC-to-DC voltage conversion. Isolation components reduce the possibility of circuit coupling between the input and output terminals, improving operational safety and stability. Isolation components typically include transformers and optocouplers. A non-isolated DC converter is a device that connects directly to the circuit to perform DC-to-DC voltage conversion without using isolation components such as transformers. A bidirectional isolated DC converter is an isolated DC converter that can transmit DC voltage in both directions; a bidirectional non-isolated DC converter is a non-isolated DC converter that can transmit DC voltage in both directions.

[0090] Depending on the actual usage scenario or requirements, in the new energy storage sub-module, the second converter 612 can be set to an isolated DC converter, that is, a bidirectional isolated DC converter; or it can be set to a non-isolated DC converter, that is, a bidirectional non-isolated DC converter, without specific limitation.

[0091] In the above solution, the second converter 612 can be configured as a bidirectional non-isolated DC converter or a bidirectional isolated DC converter, which can be selected based on the actual scenario, and has high configuration flexibility.

[0092] Please refer to Figure 7. In some embodiments, the DC bus 411 includes a first-end DC bus and a second-end DC bus. The bidirectional non-isolated DC converter includes a first inductor L1 and a first switching device Q1. The first end of the first inductor L1 is connected to the first end of the first switching device Q1 and the first-end DC bus. The second end of the first inductor L1 is connected to the energy storage module 415. The second end of the first switching device Q1 is connected to the second-end DC bus and the energy storage module 415. The third end of the first switching device Q1 is used to receive a switching signal sent by the sub-module controller.

[0093] The first-end DC bus is the positive-end DC bus or the negative-end DC bus. The second-end DC bus can also be the positive-end DC bus or the negative-end DC bus, as long as the polarity is opposite to that of the first-end DC bus. When DC bus 411 includes a first-end DC bus and a second-end DC bus, the two ends of the first-end DC bus are respectively connected to the power module 413 and the bidirectional non-isolated DC converter. The two ends of the second-end DC bus are also respectively connected to the power module 413 and the bidirectional non-isolated DC converter. The first converter 417 is connected to the first-end DC bus and the second-end DC bus between the power module 413 and the second converter 612.

[0094] The solution of this embodiment is explained by taking a bidirectional non-isolated DC converter as an example. The bidirectional non-isolated DC converter includes a first inductor L1 and a first switching device Q1, which are constructed to form a boost converter, and the boost converter is used as the bidirectional non-isolated DC converter.

[0095] Based on the new energy storage submodule of this embodiment, during actual operation, the submodule controller corresponding to the new energy storage submodule will perform voltage stabilization control of the DC bus 411. This can be done by providing one submodule controller for each new energy storage submodule, one submodule controller for multiple new energy storage submodules, or one submodule controller for all new energy storage submodules. During the voltage stabilization control of the DC bus 411, the submodule controller can obtain the DC bus voltage and the output voltage required by the current new energy storage submodule (which can be used as a DC bus voltage reference value), and complete the voltage stabilization control of the DC bus 411 using the DC bus voltage reference value and the DC bus voltage.

[0096] It is understood that there is not only one way to obtain the DC bus voltage. In some embodiments, a voltage detector may be provided at a corresponding position of the DC bus 411 to collect the DC bus voltage. In another embodiment, the voltage collection function may be integrated into the submodule controller, and the submodule controller may be connected to the corresponding position of the DC bus 411 via a high-voltage-low-voltage conversion board to realize DC bus voltage collection.

[0097] It should be noted that the method for the third terminal of the first switching device Q1 to receive the switching signal sent by the sub-module controller is not unique. In some embodiments, the third terminal of the first switching device Q1 can be connected to a high-voltage-to-low-voltage conversion board, and then connected to the sub-module controller through the high-voltage-to-low-voltage conversion board to achieve reception of the switching signal. In another embodiment, the sub-module controller can also be equipped with high-voltage operating conditions, in which case the sub-module controller is directly connected to the third terminal of the first switching device Q1.

[0098] In the above solution, the second converter 612 specifically adopts a bidirectional non-isolated DC converter, and the bidirectional non-isolated DC converter includes a first inductor L1 and a first switching device Q1, which has a simple structure and is easy to implement, and has the advantage of high economic efficiency.

[0099] In some embodiments, the new energy storage submodule further includes an insulating support assembly, and the new energy assembly 419 is disposed on the insulating support assembly.

[0100] An insulating support assembly is a support device made of insulating material and having an insulating function. In this embodiment, the new energy storage submodule includes an insulating support assembly. New energy component 419 is mounted on the insulating support assembly, which is then placed on a platform (e.g., the ground) to achieve high-voltage insulation between new energy component 419 and the ground, improving the operational safety of the new energy storage submodule.

[0101] In some embodiments, in the new energy storage submodule, the power module 413, the energy storage module 415 and the new energy component 419 are all arranged on an insulating support component, and are set up on a placement platform through the insulating support component to improve the operating safety of the new energy storage submodule.

[0102] It can be understood that the power module 413, the energy storage module 415 and the new energy component 419 can be distributed and set up in different insulating support components, or can be set up in one insulating support component at the same time, without specific limitation.

[0103] It should be noted that the specific type of the insulating support assembly is not limited, and any device having an insulating support function can be used. For example, in some embodiments, the insulating support assembly includes a support insulator.

[0104] In the above solution, the new energy component 419 is arranged on the insulating support component, and voltage isolation is performed through the insulating support component, thereby improving the operating reliability of the new energy component 419.

[0105] In some embodiments, the first converter 417 includes a non-isolated DC converter.

[0106] This embodiment illustrates the DC power output of new energy component 419. This arrangement of new energy component 419 within the insulating support assembly addresses the high-voltage isolation issue of new energy component 419. Therefore, when new energy component 419 is connected to DC bus 411, no further electrical isolation is required. This embodiment eliminates the need for a high-voltage isolation converter in a new energy grid-connected system, enabling grid connection of new energy component 419 via a non-isolated converter. Specifically, new energy component 419 is connected to DC bus 411 via a non-isolated DC converter.

[0107] In the above solution, when the new energy component 419 is voltage-isolated by the insulating support component, the first converter 417 between the new energy component 419 and the DC bus 411 directly adopts a non-isolated first converter 417, which can effectively reduce costs.

[0108] It can be understood that in another embodiment, when the new energy component 419 is arranged in an insulating support component, in order to further improve the high-voltage isolation reliability of the new energy component 419, the first converter 417 can also be set as an isolated DC converter, and the specific selection can be made based on actual needs.

[0109] Please refer to Figure 8. In some embodiments, the DC bus 411 includes a first-end DC bus and a second-end DC bus. The non-isolated DC converter includes a first capacitor C1, a second inductor L2, and a second switching device Q2. The first end of the first capacitor C1 is connected to the new energy component 419 and the first end of the second inductor L2. The second end of the second inductor L2 is connected to the first end of the second switching device Q2 and the first-end DC bus. The second end of the first capacitor C1 is connected to the new energy component 419 and the second end of the second switching device Q2. The second end of the second switching device Q2 is also connected to the second-end DC bus. The third end of the second switching device Q2 is used to receive a switching signal sent by the sub-module controller.

[0110] In the solution of this embodiment, the non-isolated DC converter includes a first capacitor C1, a second inductor L2, and a second switching device Q2. That is, a boost-type converter is constructed by the first capacitor C1, the second inductor L2, and the second switching device Q2 to achieve DC voltage conversion and output from the new energy component 419 to the energy storage module 415.

[0111] Based on the non-isolated DC converter of the embodiment of the present application, the submodule controller corresponding to the new energy energy storage submodule can realize maximum power point tracking (MPPT, Maximum Power Point Tracking) control. Specifically, an MPPT controller is provided in the submodule controller. During the operation of the new energy component 419, the output current and output voltage of the new energy component 419 are obtained through the MPPT controller, and the maximum power point tracking is performed according to the output current and output voltage to obtain the voltage parameters required by the new energy component 419 when it is running at the maximum power point, that is, the target output voltage. Afterwards, the submodule controller uses the target output voltage as a reference value, and regulates it in combination with the output voltage of the new energy component 419, and controls the operation of the first converter 417 with the regulation result. Specifically, the on-off of the second switching device Q2 in the first converter 417 is controlled to complete the maximum power point tracking.

[0112] It is understood that in some embodiments, the new energy storage submodule may only include the first converter 417, which includes a first capacitor C1, a second inductor L2, and a second switch Q2. In this case, the submodule controller only needs to implement maximum power point tracking control based on the output voltage and output current of the new energy component 419. In this embodiment, due to the voltage clamping effect of the energy storage battery pack S in the energy storage module 415, the voltage of the DC bus 411 will not change suddenly. The energy storage battery pack S can be used to clamp the voltage of the DC bus 411, thereby achieving DC bus 411 voltage stability.

[0113] In another embodiment, the new energy storage submodule can be provided with a first converter 417 and a second converter 612 at the same time. The first converter 417 includes a first capacitor C1, a second inductor L2, and a second switch device Q2, while the second converter 612 includes a first inductor L1 and a first switch device Q1. In the solution of this embodiment, the submodule controller can not only implement maximum power point tracking control based on the output voltage and output current of the new energy component 419, but can also combine the DC bus voltage and the DC bus voltage reference value (which can be combined with the output voltage of the new energy storage submodule required to meet system requirements when the new energy storage submodule is actually put into operation in the energy storage system) to achieve DC bus 411 voltage regulation control.

[0114] In the above solution, the non-isolated DC converter is constructed by the first capacitor C1, the second inductor L2 and the second switch device Q2, that is, the boost converter is used to convert the DC voltage between the new energy component 419 and the energy storage module 415, which has the advantage of high output voltage stability.

[0115] In some embodiments, the first converter 417 includes an isolated DC converter.

[0116] Unlike the aforementioned arrangement of new energy component 419 within an insulating support assembly and the configuration of first converter 417 as a non-isolated DC converter, this embodiment addresses the high-voltage isolation issue of new energy component 419 by providing an isolated DC converter. Accordingly, this embodiment eliminates the need for new energy component 419 to be within an insulating support assembly while still ensuring safe operation of the new energy storage submodule.

[0117] In the above solution, the first converter 417 between the new energy component 419 and the DC bus 411 adopts an isolated DC converter. The high-voltage isolation of the new energy component 419 can be achieved through the isolated converter, so that the new energy component 419 can be erected without passing through an insulating support component, thereby improving the construction convenience of the new energy storage sub-module.

[0118] Referring to FIG. 9 , in some embodiments, the new energy storage submodule further includes a third converter 912 . The third converter 912 is disposed between the DC bus 411 and the power module 413 , and is connected to the DC bus 411 and the power module 413 , respectively.

[0119] The energy storage module 415 is connected to the third converter 912 via the DC bus 411, and the first converter 417 is connected to the DC bus, so that the first converter 417 is connected between the energy storage module 415 and the third converter 912. The DC power converted by the first converter 417 can be directly transmitted to the energy storage module 415 for storage.

[0120] In the above solution, the energy storage module 415 is connected to the third converter 912 via the DC bus 411, so that the new energy component 419 is directly connected between the third converter 912 and the energy storage module 415. The electric energy generated by the new energy component 419 can be transmitted to the energy storage module 415 without passing through the third converter 912, which can effectively improve the efficiency of electric energy transmission.

[0121] An embodiment of the present application also provides an operating method based on the above-mentioned new energy energy storage sub-module, including: when the electric energy storage conditions are met, the electric energy output by the new energy component is converted by the first converter and then transmitted to the energy storage module for storage; when the electric energy supply conditions are met, the electric energy output by the new energy component is converted by the first converter and the power module and then transmitted to the power grid for load power supply.

[0122] The structure of the new energy storage submodule is as shown in the above-mentioned embodiments and the accompanying drawings, and will not be described in detail here. Meeting the electric energy storage condition means that the new energy storage submodule has the need to store the electric energy generated by the new energy component 419 through the energy storage module 415. The specific form of meeting the electric energy storage condition is not unique. In some embodiments, the electric energy storage condition is considered to be met when the energy storage module 415 is not fully charged with electric energy. In other embodiments, the electric energy storage condition may be considered to be met when the energy storage system is not connected to the power grid, or when the load in the power grid cannot completely consume the electric energy generated by the new energy component 419. In other embodiments, the electric energy storage condition may be considered to be met when the new energy storage submodule receives an energy storage scheduling instruction manually sent by the user.

[0123] Meeting the power supply condition means that the new energy storage submodule has a need to power the external load via the power module 413. This specific form is not exclusive; in some embodiments, it may be that a load in the power grid has a power demand. In other embodiments, the power supply condition may be met when the new energy storage submodule receives a power scheduling instruction manually sent by the user.

[0124] It is understood that the electrical energy output by the new energy component 419 can be transmitted to the energy storage module 415 for storage while being simultaneously transmitted to the grid for power supply via the first converter and power module 413. In other words, electrical energy storage and electrical energy supply can be achieved simultaneously or separately, without specific limitation.

[0125] In the solution of this embodiment, the new energy storage submodule can transmit the electric energy generated by the new energy component 419 to the energy storage module 415 for storage, or transmit it to the power grid for load power supply according to user manual scheduling and other methods, and the specific selection can be based on actual needs.

[0126] In the above scheme, the electric energy generated by the new energy component 419 can be transmitted to the energy storage module 415 for storage according to actual conditions, and / or transmitted to the power grid to power the load, thereby reducing the waste of the electric energy generated by the new energy component 419 and improving the electric energy utilization rate of the new energy component 419.

[0127] Please refer to FIG. 10 . In some embodiments, the operation method of the new energy storage submodule further includes step 902 , step 904 , and step 906 .

[0128] Step 902: Obtain output electrical parameters of the new energy component.

[0129] Step 904 : determining the target output voltage of the new energy component when operating at maximum power according to the output electrical parameters.

[0130] Step 906 : Control the operation of the first converter according to the output electrical parameter and the target output voltage.

[0131] As shown in the above embodiments and the accompanying drawings, the new energy storage submodule further includes a controller, which is connected to the first converter. The controller can be a device independently provided relative to the submodule controller, and the submodule controller can be directly used as the controller, and the specific details are not repeated. For ease of understanding, the following explanation is given with the controller as the submodule controller. The solution of the embodiment of the present application is that the new energy storage submodule is communicatively connected to the submodule controller. When the new energy component 419 transmits DC power to the energy storage module 415, the submodule controller can obtain the output electrical parameters output by the new energy component 419 to the first converter 417, and then analyze the obtained output electrical parameters to obtain the target output voltage when the new energy component 419 in the current new energy storage submodule is running at maximum output power. Finally, the submodule controller performs feedback adjustment based on the target output voltage and output electrical parameters, so that the photovoltaic panel finally operates in a state of maximum power operation, realizing maximum power operation control of the new energy component 419.

[0132] The above solution can be combined with the output electrical parameters of the new energy component 419 to maintain the new energy component 419 running at maximum power, thereby improving the operating efficiency of the new energy component 419.

[0133] It should be noted that the specific type of output electrical parameters is not unique. In some embodiments, the output electrical parameters include output voltage and output current, namely, the output voltage and output current of the new energy component 419. Accordingly, in some embodiments, step 904 includes: performing maximum power point tracking control based on the output voltage and output current to determine the target output voltage when the new energy component operates at maximum power; and step 906 includes: controlling the operation of the first converter based on the output voltage and the target output voltage.

[0134] The solution of this embodiment uses the output voltage and output current of new energy component 419 to determine the target output voltage when new energy component 419 is operating at maximum output power. Specifically, the MPPT controller in the sub-module controller performs maximum power point tracking, and in conjunction with the MPPT algorithm, finds the target output voltage that can achieve the maximum power output of new energy component 419 at this time, and uses this target output voltage as the reference voltage. The sub-module controller then controls the obtained reference voltage and output voltage to obtain the control parameters required to ensure that the output voltage of new energy component 419 tracks the target output voltage. The obtained control parameters are used to control the operation of first converter 417.

[0135] It should be noted that the submodule controller is not the only way to obtain the output current and output voltage. In some embodiments, a voltage collector and a current collector may be provided at the output end of the new energy component 419, and the output voltage and output current may be collected by the voltage collector and the current collector, respectively, and transmitted to the submodule controller. The specific transmission method is not unique. The voltage collector and the current collector may be connected to a strong-weak current conversion board, and then the submodule controller obtains the voltage and current through the strong-weak current conversion board.

[0136] The above solution can combine the output current and output voltage of the new energy component 419 to perform maximum power point tracking control, thereby maintaining the new energy component 419 operating at the maximum power point and improving the operating efficiency of the new energy component 419.

[0137] Referring to FIG. 11 , in some embodiments, controlling the operation of the first converter according to the output voltage and the target output voltage includes steps 1002 , 1004 , and 1006 .

[0138] Step 1002 : Determine an output voltage difference by comparing the output voltage with the target output voltage.

[0139] Step 1004 , performing proportional-integral regulation according to the output voltage difference to determine a first target duty cycle.

[0140] Step 1006 : Perform pulse width modulation according to the first target duty cycle to generate a first switching signal and send it to the first converter.

[0141] Referring to Figures 7 or 8 , the first converter 417 includes a first capacitor C1, a second inductor L2, and a second switching device Q2. The submodule controller includes an MPPT controller, a comparator, a proportional integral (PI) regulator, and a pulse width modulation (PWM) signal generator. The MPPT controller of the submodule controller is connected to the output terminal of the new energy component 419 to obtain the output current I_PV of the new energy component 419. The MPPT controller is connected to the first capacitor C1 arranged in parallel with the new energy component 419, and the voltage of the first capacitor C1 is used as the output voltage U_PV of the new energy component 419. After the MPPT controller performs maximum power point tracking to obtain the target output voltage, the target output voltage and the output voltage are compared in a comparator to obtain the output voltage difference U_ref. The output voltage difference is then transmitted to the PI regulator for PI regulation, and the first target duty cycle is output. Finally, the PWM signal generator generates a corresponding first switching signal in combination with the first target duty cycle, and sends it to the second switching device Q2. The switching signal is used to control the on and off of the second switching device Q2 to complete the maximum power tracking control.

[0142] The above scheme combines the output voltage and the target output voltage to perform proportional-integral regulation, and performs pulse width modulation on the result of the proportional-integral regulation, thereby determining the first switching signal required for the operation of the first converter 417, and performing on-off control on the first converter 417, thereby realizing the operation control of the first converter 417 with high control accuracy.

[0143] Please refer to FIG. 12 . In some embodiments, the operating method of the new energy storage submodule further includes steps 112 and 114 .

[0144] Step 112: Obtain a DC bus voltage reference value and a DC bus voltage.

[0145] Step 114 : performing voltage stabilization control on the DC bus according to the DC bus voltage reference value and the DC bus voltage.

[0146] The DC bus voltage reference value refers to the output voltage required by a single new energy storage submodule, calculated based on actual power demand, when the new energy storage submodule is connected to the energy storage system and the energy storage system operates with a fixed number of new energy storage submodules. The new energy storage submodule is in communication with the submodule controller (a high-voltage to low-voltage conversion board may be provided between the two). During the charging and discharging process of energy storage module 415, the submodule controller can obtain the DC bus voltage reference value and the DC bus voltage to perform voltage regulation control to maintain a stable DC bus voltage.

[0147] Similarly, there is not only one way to obtain the DC bus voltage. A voltage detector can be set at the corresponding position of the DC bus 411 to collect the DC bus voltage; or the voltage collection function can be integrated into the sub-module controller, and the sub-module controller is connected to the high-voltage-low-voltage conversion board, and then connected to the corresponding position of the DC bus 411 through the high-voltage-low-voltage conversion board to realize DC bus voltage collection. There is no specific limitation.

[0148] The above solution can also be combined with the DC bus voltage and the DC bus voltage reference value to achieve voltage stabilization control of the DC bus 411, effectively improving the operational reliability of the new energy storage sub-module.

[0149] Referring to FIG. 13 , in some embodiments, step 114 includes step 122 , step 124 , and step 126 .

[0150] Step 122 : Determine the bus voltage difference by comparing the DC bus voltage reference value with the DC bus voltage.

[0151] Step 124 , performing proportional-integral adjustment according to the bus voltage difference to determine a second target duty cycle.

[0152] Step 126 : Perform pulse width modulation according to the second target duty cycle to generate a second switching signal and send it to the second converter.

[0153] With reference to FIG. 7 , in the embodiment of the present application, the second converter 612 includes a first inductor L1 and a first switching device Q1, and the submodule controller includes a comparator, a PI regulator, and a PWM signal generator. The submodule controller obtains the voltage across the DC support capacitor C in the power module 413 and uses it as the DC bus voltage. The DC bus voltage and the DC bus voltage reference value are subjected to a difference comparison in the comparator to obtain the bus voltage difference. The bus voltage difference is then transmitted to the PI regulator for PI regulation, and a second target duty cycle is output. Finally, the PWM signal generator generates a corresponding second switching signal based on the second target duty cycle and sends it to the first switching device Q1. The switching signal is used to control the on and off of the first switching device Q1, thereby completing the voltage regulation control of the DC bus 411.

[0154] The above scheme combines the bus voltage difference between the DC bus voltage reference value and the DC bus voltage, performs proportional-integral regulation and pulse width modulation in sequence, and finally generates a second switching signal to control the operation of the second converter 612. That is, the DC bus 411 is controlled by the second converter 612, which has the advantage of high voltage control accuracy.

[0155] An embodiment of the present application further provides an energy storage valve, comprising a submodule controller and the above-mentioned new energy storage submodule, wherein the new energy storage submodule is communicatively connected to the submodule controller, and each new energy storage submodule is cascaded.

[0156] The submodule controller is used to execute the steps of the operation method of any of the above-mentioned new energy storage submodules. The specific structure of the new energy storage submodule and the implementation of its operation mode are as shown in the above-mentioned embodiments and the accompanying drawings, and will not be repeated here. In actual scenarios, each new energy storage submodule of the energy storage valve is connected to a corresponding submodule controller, that is, each submodule controller independently controls the operation of the new energy storage submodule connected to it in communication. In other embodiments, a submodule controller can also be selected according to actual needs to simultaneously control the operation of two or more new energy storage submodules, without specific limitation.

[0157] It should be noted that after cascading, the new energy storage submodules can be connected to either the AC or DC grid. When connected to the AC grid, the connection can be similar to that shown in Figures 2 and 3 , with the SM# submodule including the new energy storage submodule. When connected to the DC grid, after cascading, the new energy storage submodules are connected to the positive and negative lines of the DC grid. Furthermore, the new energy storage submodules can be mixed with energy storage submodules and photovoltaic submodules to connect to either the AC or DC grid to better meet the various grid requirements.

[0158] In the solution of the embodiment of the present application, each cascaded new energy energy storage sub-module distributes the new energy component 419 in each new energy energy storage sub-module, modularizes the new energy component 419, has good flexibility, and can reduce the impact of a single failure of the new energy component 419 on the new energy grid-connected system. That is, when a single new energy component 419 fails, the new energy storage sub-module where the failed new energy component is located can be removed, which will not have a significant impact on the operation of other new energy components 419, thereby increasing the proportion of the operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0159] It should be pointed out that the new energy storage submodule provided in this application can not only be constructed in the above-mentioned cascade manner to form a DC type energy storage valve, but can also be constructed to form an AC energy storage valve. You don’t need to choose which one you want, and you can choose it based on your actual needs.

[0160] An embodiment of the present application also provides an energy storage system, including a converter valve and the above-mentioned energy storage valve, wherein the first end and the second end formed by cascading each new energy storage submodule are respectively connected to the converter valve, and the converter valve is used to connect to the AC power grid.

[0161] The cascaded new energy storage submodules in the energy storage valve are as shown in the above-mentioned embodiments and drawings, and will not be described in detail here. In the embodiments of the present application, the converter valve can be a converter valve including at least one of a voltage source converter valve, a grid-commutated converter valve, and a cascade converter valve.

[0162] There is no single type of converter valve; any device capable of performing rectification and inversion functions can be used, and the configuration can be tailored to actual needs. For example, in some embodiments, the converter valve comprises a grid-commutated converter valve or a VSC converter valve. In some embodiments, the VSC converter valve can also be two single-level converters, a three-level converter, or the modular multilevel converter valve shown in Figure 2, without limitation. In other embodiments, the converter valve can also employ the cascade converter valve shown in Figure 3, with the configuration tailored to actual needs.

[0163] Through this solution, the new energy components 419 are distributedly set in various new energy energy storage sub-modules, and the new energy components 419 are modularized, which has good flexibility and can reduce the impact of single failures of new energy components 419 on the new energy grid-connected system. That is, when a single new energy component 419 fails, the new energy storage sub-module where the failed new energy component is located can be removed, which will not have a major impact on the operation of other new energy components 419, thereby increasing the proportion of operating time of the new energy grid-connected system, thereby effectively improving the system availability of the new energy grid-connected system.

[0164] Please refer to FIG. 14 . An embodiment of the present application further provides an operating method based on the above energy storage system, including step 132 and step 134 .

[0165] Step 132 : When the new energy component has output, obtain the new energy output power of the new energy component and the system required power of the AC power grid.

[0166] Step 134 : Control the new energy component to output electrical energy according to the new energy output power and the system required power.

[0167] The energy storage system structure is as described in the various embodiments and accompanying figures above. The new energy output power is the sum of the output powers of the new energy components 419 in each new energy storage submodule with new energy output. The system demand power is the sum of the power demands of each electrical device in the AC power grid. This power demand is obtained through statistical analysis of the AC power grid and transmitted to the system controller.

[0168] In this embodiment, the energy storage system includes the aforementioned energy storage valve, converter valve, and control device. The energy storage valve and converter valve are each connected to the control device. During operation of the energy storage system, the control device obtains the output power of the renewable energy source and the system's required power, and then, based on the relationship between the two, supplies power to the AC grid. It should be noted that the overall logic of the energy storage system's operational control should prioritize the AC grid. Specifically, if the renewable energy source output power exceeds the required power, the excess power is transferred to the energy storage module 415 for storage.

[0169] The operating method of the above-mentioned energy storage system combines the new energy output power of the new energy component 419 and the system demand power of the AC power grid to realize the output power control of the new energy component 419, smooth the power output of the power grid, realize the high integration of new energy power generation and energy storage, and improve the grid-connected operation reliability of the energy storage system.

[0170] In some embodiments, step 134 includes: when the output power of the new energy is greater than the system required power, controlling the new energy component to output electric energy to the AC power grid and the energy storage module; when the output power of the new energy is equal to the system required power, controlling the new energy component to output electric energy to the AC power grid; when the output power of the new energy is less than the system required power, controlling the new energy component and the energy storage module to output electric energy to the AC power grid at the same time.

[0171] In the solution of this embodiment, if the output power of the new energy is greater than the power required by the system, after the output power of the new energy component 419 meets the needs of the AC power grid, the remaining output power will be supplied to the energy storage module 415 to charge the energy storage module 415. In this case, the control device conducts the connection between each new energy component 419 and the AC power grid (which can be achieved by turning on the new energy inverter), and the electric energy generated by the new energy component 419 is transmitted to the AC power grid. When the needs of the AC power grid are met, the control device conducts the connection between the remaining new energy components 419 and the energy storage module 415. Specifically, if only the first converter 417 is provided, it is sufficient to control the first converter 417 to be turned on. If the first converter 417 and the second converter 612 are provided at the same time, it is necessary to control both the first converter 417 and the second converter 612 to be turned on and run.

[0172] It can be understood that in some embodiments, when the new energy output power is greater than the system demand power, the control device can combine the power status of the energy storage module 415 in each new energy storage sub-module, and give priority to controlling the new energy components 419 in the same new energy storage sub-module as the energy storage module 415 with higher power, and connect them to the AC power grid for operation. The remaining new energy components 419 charge the corresponding energy storage modules 415 with lower power, thereby further improving the operational reliability of the energy storage system.

[0173] If the output power of the new energy is equal to the power required by the system, the power output by the new energy component 419 is just used by the AC system. Therefore, it is only necessary to control the new energy components 419 in each new energy storage sub-module to connect to the AC power grid for operation. At this time, the energy storage module 415 is neither charging nor discharging.

[0174] If the new energy output power is less than the system demand power, the output power of the new energy component 419 cannot meet the needs of the AC power grid, and it is necessary to control the energy storage module 415 of some or all of the new energy storage sub-modules to provide power to the AC power grid, that is, at this time some or all of the energy storage modules 415 are discharged.

[0175] The above solution controls the power transmission of the new energy component 419 and the charging and discharging of the energy storage module 415 according to the relationship between the output power of the new energy and the power required by the system, thereby effectively improving the operating efficiency of the energy storage system.

[0176] In some embodiments, the method for operating the energy storage system further includes: controlling the energy storage module 415 to output electric energy to the AC power grid when the new energy component 419 does not output electric energy.

[0177] The new energy component 419 has no output, that is, all new energy components 419 in the energy storage system have no power output, that is, the new energy component 419 is not performing power conversion (this may be due to a new energy component 419 failure, outage, or nighttime scenario). In this case, in order to meet the power demand of the AC power grid, it is necessary to control the discharge of the energy storage module 415 of some or all new energy storage sub-modules based on the system power demand.

[0178] In the above solution, when the new energy component 419 has no output, the energy storage module 415 supplies power to the AC grid to meet the load demand of the AC grid and improve the functional reliability of the energy storage system for the AC grid.

[0179] In some embodiments, the energy storage system operation method further includes: when the new energy storage submodule is bypassed, disconnecting the power transmission between the new energy component 419 and the energy storage module 415 .

[0180] Bypassing the new energy storage submodule, or cutting the new energy storage submodule out of the energy storage system, requires disconnecting the power transmission between the new energy component 419 and the energy storage module 415 to improve operational safety. This disconnection short-circuits the grid-connected side of the power module 413, thereby short-circuiting the new energy storage submodule. This disconnection removes the new energy storage submodule from the energy storage system and its power exchange with the grid. However, this does not affect the power exchange between other new energy storage submodules connected to the energy storage system and the grid.

[0181] It should be noted that there is not only one way to disconnect the power transmission between the new energy component 419 and the energy storage module 415. In some embodiments, if the new energy storage submodule includes only the first converter 417, it is sufficient to disconnect only the first converter 417. In another embodiment, if the new energy storage submodule includes the first converter 417 and the second converter 612, the power transmission between the new energy component 419 and the energy storage module 415 can be interrupted by disconnecting at least one of the first converter 417 and the second converter 612.

[0182] The above solution interrupts the transmission of electric energy from the new energy component 419 to the energy storage module 415 when the new energy storage submodule is bypassed, thereby improving the operational safety of the energy storage module 415 .

[0183] In some embodiments, the operation method of the energy storage system also includes: when the energy storage module 415 is fully charged, disconnecting the power transmission between the new energy component 419 and the energy storage module 415; when the energy storage module 415 is discharged to reach a preset power threshold, turning on the power transmission between the new energy component 419 and the energy storage module 415.

[0184] Full charge means that the charge of the energy storage battery pack S in the energy storage module 415 reaches a preset full charge threshold. In the solution of this embodiment, if the new energy component 419 transmits electrical energy to the energy storage module 415 to charge the energy storage module 415, the control device will obtain the charge of the energy storage module 415 in real time (which can be obtained through the battery management system of the energy storage battery pack S) for analysis. When the charge of the energy storage battery pack S reaches the preset full charge threshold, the control device will control the first converter 417 to stop operating, interrupting the charging of the energy storage module 415. After that, the control device will continuously monitor the charge of the energy storage module 415. If it is found that the energy storage module 415 is discharged and the charge reaches the preset charge threshold, it can control the first converter 417 to start and charge the energy storage module 415 again.

[0185] In the above solution, when the energy storage module 415 is fully charged, the new energy component 419 is interrupted from transmitting power to the energy storage module 415 , thereby reducing the possibility of overcharging the energy storage module 415 and improving the charging safety of the energy storage module 415 .

[0186] In order to facilitate understanding of the technical solution of the present application, the present application is explained below in conjunction with more detailed embodiments.

[0187] Referring to Figures 1 to 8 , the main topology of the energy storage system includes a converter valve, a DC direct-connected energy storage valve, and a control device. The DC direct-connected energy storage valve includes cascaded new energy storage sub-modules, and each new energy storage sub-module is respectively provided with a corresponding sub-module controller, and each sub-module controller is respectively connected to the control device.

[0188] In the new energy storage submodule, the new energy component 419 is arranged on an insulating support component and is set up on a placement platform (ground) through the insulating support component. The new energy component 419 is connected to the DC bus 411 between the power module 413 and the second converter 612 through the first converter 417, and the energy storage module 415 is connected to the second converter 612. Specifically, the DC bus 411 includes a first-end DC bus and a second-end DC bus. The bidirectional non-isolated DC converter includes a first inductor L1 and a first switching device Q1. The first end of the first inductor L1 is connected to the first end of the first switching device Q1 and the first-end DC bus. The second end of the first inductor L1 is connected to the energy storage module 415. The second end of the first switching device Q1 is connected to the second-end DC bus and the energy storage module 415. The third end of the first switching device Q1 is connected to the submodule controller.

[0189] The first converter 417 adopts a non-isolated DC converter, including a first capacitor C1, a second inductor L2, and a second switching device Q2. The first end of the first capacitor C1 is connected to the new energy component 419 and the first end of the second inductor L2, the second end of the second inductor L2 is connected to the first end of the second switching device Q2 and the first-end DC bus, the second end of the first capacitor C1 is connected to the new energy component 419 and the second end of the second switching device Q2, the second end of the second switching device Q2 is also connected to the second-end DC bus, and the third end of the second switching device Q2 is connected to the sub-module controller.

[0190] The processing logic of the control device under normal operation:

[0191] 1) New energy output power > system power requirement. New energy component 419 outputs power to the AC grid and energy storage module 415. At this time, energy storage module 415 is charged (in this case, the power requirement of the AC grid must be met first).

[0192] 2) New energy output power = system demand power, the new energy component 419 outputs power to the AC grid, and the energy storage module 415 neither charges nor discharges;

[0193] 3) The new energy output power is less than the system demand power. The new energy component 419 and the energy storage module 415 output power to the AC grid, and the energy storage module 415 discharges.

[0194] 4) If the new energy component 419 has no output, the energy storage module 415 outputs real-time matching of the load demand of the AC power grid.

[0195] Processing logic of the control device in special cases:

[0196] 1) If the new energy storage submodule fails and is bypassed, the new energy power output of the module is shut down through the first converter 417;

[0197] 2) If the energy storage module 415 is fully charged, the first converter 417 and / or the second converter 612 are used to shut down the new energy power output of the module, and the energy storage module 415 is discharged. After the discharge reaches a certain threshold, the new energy component 419 is connected again.

[0198] In a renewable energy grid-connected system, maximum power point tracking (MPPT) control and constant DC voltage control need to be implemented simultaneously. When only the first converter 417 is present, MPPT control can be implemented by the boost converter (i.e., the first converter 417) connected to the renewable energy component 419. The specific implementation method is as follows: the submodule controller obtains the DC bus 411 current I_PV (i.e., output current) of the renewable energy component 419 and the voltage U_PV of the second capacitor (i.e., output voltage of the renewable energy component 419). It then uses the MPPT algorithm to find the voltage that achieves maximum power output from the renewable energy component 419 at this point, and outputs it as the reference voltage U_ref. The output reference voltage is compared with the voltage U_PV to obtain an error, which is input into the PI regulator. The output of the PI regulator is the first target duty cycle, which is modulated by PWM to generate the first switching signal, implementing closed-loop voltage control of the boost converter, thereby achieving MPPT control of the renewable energy component 419. For DC bus 411 voltage regulation control, DC voltage clamping can be achieved directly using the voltage of the energy storage battery pack S in the parallel energy storage module 415.

[0199] When both the first converter 417 and the second converter 612 exist: the MPPT control is the same as described above, and is implemented by the boost converter connected to the new energy component 419. The DC bus voltage stabilization can be achieved by the boost converter (the second converter 612). The specific implementation method is as follows: the submodule controller obtains a given DC bus voltage reference value U_dc_ref, and makes a difference with the voltage (DC bus voltage) on the obtained DC support capacitor C to obtain the bus voltage error and input it into the PI regulator. The output value of the PI regulator is the second target duty cycle of the boost converter connected to the energy storage module 415. After PWM modulation, a second switching signal is generated to realize the voltage closed-loop control of the DC support capacitor C, thereby realizing the DC bus voltage stabilization control.

[0200] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A new energy storage submodule, comprising: DC bus; A power module, comprising a grid connection side and a DC side, wherein the grid connection side of the power module is used to be cascaded with an adjacent new energy storage submodule; An energy storage module, connected to the DC side of the power module via the DC bus; A first converter connected to the DC bus; and The new energy component is connected to the first converter.

2. The new energy storage submodule according to claim 1, wherein: The new energy storage submodule also includes a second converter, which is arranged between the DC bus and the energy storage module and is connected to the DC bus and the energy storage module respectively.

3. The new energy storage submodule according to claim 2, wherein: The second converter includes a bidirectional non-isolated DC converter or a bidirectional isolated DC converter.

4. The new energy storage submodule according to any one of claims 1 to 3, wherein: The new energy storage submodule also includes an insulating support component, and the new energy component is arranged on the insulating support component.

5. The new energy storage submodule according to claim 4, wherein: The first converter comprises a non-isolated DC converter.

6. The new energy storage submodule according to any one of claims 1 to 3, wherein: The first converter includes an isolated DC converter.

7. The new energy storage submodule according to claim 1, wherein: The new energy storage submodule also includes a third converter, which is arranged between the DC bus and the power module and is connected to the DC bus and the DC side of the power module respectively.

8. The new energy storage submodule according to any one of claims 1 to 7, wherein: The new energy components include photovoltaic components.

9. An operating method based on the new energy storage submodule according to any one of claims 1 to 8, comprising: When the electric energy storage conditions are met, the electric energy output by the new energy component is converted by the first converter and then transmitted to the energy storage module for storage; When the power supply conditions are met, the power output by the new energy component is converted by the first converter and the power module, and then transmitted to the power grid to supply power to the load.

10. The method according to claim 9, wherein: The operation method of the new energy storage submodule also includes: Obtaining output electrical parameters of the new energy component; Determining, based on the output electrical parameters, a target output voltage of the new energy component when operating at maximum power; The first converter is controlled to operate according to the output electrical parameter and the target output voltage.

11. The method according to claim 10, wherein: The output electrical parameters include output voltage and output current, and determining the target output voltage of the new energy component when operating at maximum power according to the output electrical parameters includes: Perform maximum power point tracking control according to the output voltage and the output current to determine a target output voltage of the new energy component when it is running at maximum power; Controlling the operation of the first converter according to the output electrical parameter and the target output voltage includes: controlling the operation of the first converter according to the output voltage and the target output voltage.

12. The method according to claim 11, wherein: The step of controlling the first converter to operate according to the output voltage and the target output voltage includes: Determine an output voltage difference by comparing the output voltage with the target output voltage; Performing proportional-integral regulation according to the output voltage difference to determine a first target duty cycle; Pulse width modulation is performed according to the first target duty cycle to generate a first switching signal and send it to the first converter.

13. The method according to any one of claims 9 to 12, wherein: The operation method of the new energy storage submodule also includes: Obtain a DC bus voltage reference value and a DC bus voltage; The DC bus is subjected to voltage stabilization control according to the DC bus voltage reference value and the DC bus voltage.

14. The method according to claim 13, wherein: The step of performing voltage stabilization control on the DC bus according to the DC bus voltage reference value and the DC bus voltage comprises: Determine a bus voltage difference by comparing the DC bus voltage reference value with the DC bus voltage; Perform proportional-integral regulation according to the bus voltage difference to determine a second target duty cycle; Pulse width modulation is performed according to the second target duty cycle to generate a second switching signal and send it to the second converter.

15. An energy storage valve, comprising a submodule controller and the new energy storage submodule according to any one of claims 1 to 8, wherein the submodule controller and the new energy storage submodule are communicatively connected, and each of the new energy storage submodules is cascaded.

16. An energy storage system, comprising a converter valve and the energy storage valve according to claim 15, wherein the first end and the second end formed by cascading each of the new energy storage submodules are respectively connected to the converter valve, and the converter valve is used to connect to an AC power grid.

17. The energy storage system according to claim 16, wherein: The converter valve includes at least one of a voltage source converter valve, a grid-commutated converter valve and a cascade converter valve.

18. A method for operating the energy storage system according to any one of claims 16 to 17, comprising: When the new energy component has output, obtaining the new energy output power of the new energy component and the system required power of the AC power grid; According to the new energy output power and the system required power, the new energy component is controlled to output electric energy.

19. The method according to claim 18, wherein: The step of controlling the new energy component to output electric energy according to the new energy output power and the system required power includes: When the output power of the new energy source is greater than the power required by the system, controlling the new energy component to output electric energy to the AC power grid and the energy storage module; When the output power of the new energy is equal to the power required by the system, controlling the new energy component to output electric energy to the AC power grid; When the output power of the new energy source is less than the power required by the system, the new energy component and the energy storage module are controlled to output electric energy to the AC power grid at the same time.

20. The method according to claim 18 or 19, wherein: The operation method of the energy storage system further includes: When the new energy component has no output, the energy storage module is controlled to output electric energy to the AC power grid.

21. The method according to any one of claims 18 to 20, wherein: The operation method of the energy storage system further includes: When the new energy storage submodule is bypassed, the power transmission between the new energy component and the energy storage module is disconnected.

22. The method according to any one of claims 18 to 21, wherein: The operation method of the energy storage system further includes: When the energy storage module is fully charged, disconnecting the power transmission between the new energy component and the energy storage module; When the energy storage module is discharged to a preset power threshold, power transmission between the new energy component and the energy storage module is turned on.

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