Energy storage systems and inverter systems

Abstract

This application discloses an energy storage system and an inverter system, belonging to the technical field of energy storage systems. The energy storage system includes: at least one set of energy storage modules; an inverter module, the inverter module including a boost module and a first DC / DC converter, one end of the first DC / DC converter being connected to the high-voltage bus of the inverter module and connected to the boost module via the high-voltage bus; the other end of the first DC / DC converter being connected to each of the energy storage modules via low-voltage buses. The energy storage system of this application achieves composite DC coupling, and through dual buses, it achieves direct decoupling between the energy storage modules and the inverter module, facilitating energy management of multiple energy storage modules, reducing the coupling influence between components, and simplifying system control.

Description

Technical Field

[0001] This application belongs to the field of energy storage system technology, and particularly relates to an energy storage system and an inverter system. Background Technology

[0002] With the miniaturization of photovoltaic (PV) energy storage systems, more and more PV energy storage systems are being deployed in individual households. Considering the operation and electrical safety of individual users, energy storage systems are increasingly favoring lightweight designs, providing more flexible options for individual users. In existing miniaturized PV energy storage products, such as those for balconies, the energy of the battery packs is coupled to the inverter module via a low-voltage DC bus. This architecture is not conducive to managing the energy of multiple battery packs, and the coupling between different parts has a significant impact, resulting in complex system control. Utility Model Content

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes an energy storage system and an inverter system that achieves composite DC coupling. Direct decoupling of the energy storage module and the inverter module is achieved through a dual-bus system, facilitating energy management of multiple energy storage modules, reducing the coupling effects between components, and simplifying system control.

[0004] In a first aspect, this application provides an energy storage system, comprising:

[0005] At least one set of energy storage modules;

[0006] The inverter module includes a boost module and a first DC / DC converter. One end of the first DC / DC converter is connected to the high-voltage bus of the inverter module and is connected to the boost module via the high-voltage bus. The other end of the first DC / DC converter is connected to each of the energy storage modules via a low-voltage bus.

[0007] According to the energy storage system provided in the embodiments of this application, a first DC / DC converter is connected to each energy storage module via a low-voltage bus, and low-voltage DC bus coupling technology is used to realize the coupling expansion of the energy storage modules. At the same time, the first DC / DC converter is connected to the boost module via a high-voltage bus, and high-voltage bus coupling is used to realize the power transmission between the energy storage module and the inverter module, realizing a composite DC coupling. The dual bus realizes the direct decoupling of the energy storage module and the inverter module, which facilitates the energy management of multiple energy storage modules, reduces the coupling influence between components, and simplifies system control.

[0008] In one embodiment of the energy storage system of this application, a first terminal of the first DC / DC converter is connected to the positive bus of the high-voltage bus, a second terminal is connected to the negative bus of the high-voltage bus, a third terminal is connected to each of the energy storage modules via the positive bus of the low-voltage bus, and a fourth terminal is connected to each of the energy storage modules via the negative bus of the low-voltage bus.

[0009] One embodiment of the energy storage system of this application further includes:

[0010] A first capacitor is connected in parallel with the third and fourth terminals.

[0011] One embodiment of the energy storage system of this application includes an energy storage module comprising:

[0012] A second DC / DC converter, one end of which is connected to the other end of the first DC / DC converter;

[0013] A battery pack is connected to the other end of the second DC / DC converter; the output voltage of the battery pack is less than a first voltage threshold.

[0014] In one embodiment of the energy storage system of this application, the first DC / DC converter is an isolated converter.

[0015] In one embodiment of the energy storage system of this application, the first DC / DC converter is a bidirectional DC / DC converter.

[0016] In one embodiment of the present application, an energy storage system is provided in which the first DC / DC converter is configured to switch to a corresponding conversion direction based on the charging and discharging state of the energy storage module.

[0017] In one embodiment of the energy storage system of this application, one end of the boost module is configured to connect to a new energy power generation device, and the other end of the boost module is connected to one end of the first DC / DC converter via the high-voltage bus.

[0018] In one embodiment of the energy storage system of this application, the boost module is an isolated converter.

[0019] One embodiment of the energy storage system of this application includes an inverter module comprising:

[0020] A DC / AC converter, one end of which is connected to one end of the first DC / DC converter via the high-voltage bus, and the other end of which is configured to be connected to the power grid.

[0021] In one embodiment of the energy storage system of this application, the number of the at least one set of energy storage modules is multiple, the energy storage modules are connected in parallel, and each energy storage module is connected to the other end of the first DC / DC converter.

[0022] In one embodiment of the energy storage system of this application, the number of the at least one set of energy storage modules is one.

[0023] Secondly, this application provides an inverter system, comprising:

[0024] Boost module;

[0025] A first DC / DC converter, one end of which is connected to the high-voltage bus of the inverter system and connected to the boost module via the high-voltage bus; the other end of the first DC / DC converter is configured to be connected to each energy storage module via a low-voltage bus.

[0026] The above-described one or more technical solutions in the embodiments of this application have at least one of the following technical effects:

[0027] By connecting the first DC / DC converter to each energy storage module via a low-voltage bus, the coupling capacity of the energy storage modules is expanded using low-voltage DC bus coupling technology. Simultaneously, the first DC / DC converter is connected to the boost module via a high-voltage bus, and power transmission between the energy storage module and the inverter module is achieved using high-voltage bus coupling, realizing a composite DC coupling. Direct decoupling between the energy storage module and the inverter module is achieved through dual buses, facilitating energy management of multiple energy storage modules, reducing the coupling influence between components, and simplifying system control.

[0028] Furthermore, by simplifying the inverter module, the energy of the new energy power generation device can be directly transmitted to the grid through the high-voltage bus. While ensuring power safety, this improves the efficiency of the inverter module, making the energy transmission through the grid connection path more efficient and reducing the energy loss of the new energy power generation device when it is directly utilized. In addition, the battery is independently managed through the low-voltage bus, reducing intermediate conversion links and lowering losses.

[0029] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0030] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0031] Figure 1 This is a schematic diagram of the energy storage system provided in the embodiments of this application.

[0032] Figure label:

[0033] Energy storage module 110; inverter module 120; boost module 130; first DC / DC converter 140;

[0034] Second DC / DC converter 150; battery pack 160; DC / AC converter 170; first capacitor C1;

[0035] The second capacitor is C2. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0037] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0038] 1. In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0039] 2. In the description of this application, "multiple" means two or more.

[0040] This application provides an energy storage system.

[0041] like Figure 1 As shown, in some embodiments, the energy storage system includes at least one set of energy storage modules 110 and inverter modules 120.

[0042] In this embodiment, the number of at least one set of energy storage modules 110 can be one set.

[0043] When the number of at least one set of energy storage modules 110 is one set, the energy storage system is in the form of an integrated energy storage unit, that is, the energy storage system includes a set of energy storage modules 110 and an inverter module 120.

[0044] The energy storage module 110 is the energy storage unit of the system. Each energy storage module 110 works independently and can be expanded according to the system capacity requirements.

[0045] By coupling a set of energy storage modules 110 and inverter modules 120 through an interface, the functions of an energy storage system can be realized.

[0046] In some embodiments, the number of at least one set of energy storage modules 110 can be multiple sets.

[0047] In this embodiment, another set of identical energy storage modules 110 can be coupled together with a set of energy storage modules 110 and inverter modules 120 to expand the energy storage capacity of the system and increase the flexibility of stacked products.

[0048] When the energy storage system includes multiple sets of energy storage modules 110, the multiple sets of energy storage modules 110 can be connected in parallel.

[0049] The inverter module 120 may include a boost module 130 and a first DC / DC converter 140.

[0050] The boost module 130 can convert a lower voltage to a higher voltage.

[0051] When the energy storage system includes multiple sets of energy storage modules 110, the multiple sets of energy storage modules 110 can be connected in parallel to the other end of the first DC / DC converter 140 respectively.

[0052] The first DC / DC converter 140 can convert low voltage to high voltage, or high voltage to low voltage.

[0053] In some embodiments, one end of the boost module 130 is configured to connect to a new energy power generation device (such as...). Figure 1 (As shown on the PV side), the other end of the boost module 130 is connected to one end of the first DC / DC converter 140 via the high-voltage bus.

[0054] In this embodiment, the new energy power generation device may include solar power generation device (such as photovoltaic module), wind power generation device, and biomass power generation device, etc.

[0055] The other end of the boost module 130 can be connected to the high-voltage side of the first DC / DC converter 140 via the high-voltage bus.

[0056] The boost module 130 can achieve maximum power point tracking (MPPT) function, which can make the new energy power generation device always work at the maximum power point by adjusting the input voltage or current, so as to improve the power generation efficiency.

[0057] The boost module 130 can convert the low voltage (such as less than 60V) on the side of the new energy power generation device into high voltage DC (greater than 310V).

[0058] The energy from the new energy power generation device is directly transmitted to the inverter through the high-voltage bus, which can reduce the loss on the low-voltage side and improve the conversion efficiency of the new energy power generation device to the grid.

[0059] In some embodiments, the boost module 130 may be an isolated converter.

[0060] In this embodiment, the boost module 130 can adopt an isolated DC / DC converter structure (such as an LLC resonant converter), which can achieve electrical isolation between the input (photovoltaic side) and the output (high voltage bus side), improve system safety, and adapt to different voltage levels.

[0061] An isolated transformer can be installed in the boost module 130 to achieve electrical isolation.

[0062] The inverter module 120 can be used to boost the ground voltage of the new energy power generation device to the high voltage bus and realize bidirectional energy conversion between the high voltage bus and the low voltage bus.

[0063] One end of the first DC / DC converter 140 is connected to the high-voltage bus of the inverter module 120, and is connected to the boost module 130 via the high-voltage bus.

[0064] High-voltage busbars are used to carry and transmit high-voltage currents. High-voltage busbars can transmit voltages greater than 310V.

[0065] The other end of the first DC / DC converter 140 is connected to each energy storage module 110 via a low-voltage bus.

[0066] Low-voltage busbars are used to carry and transmit low-voltage current; they can transmit voltages less than 60V.

[0067] According to the energy storage system provided in the embodiments of this application, a first DC / DC converter 140 is connected to each energy storage module 110 via a low-voltage bus, and low-voltage DC bus coupling technology is used to realize the coupling expansion of the energy storage module 110. At the same time, the first DC / DC converter 140 is connected to the boost module 130 via a high-voltage bus, and high-voltage bus coupling is used to realize the power transmission between the energy storage module 110 and the inverter module 120, realizing a composite DC coupling. The direct decoupling of the energy storage module 110 and the inverter module 120 is realized through the dual bus, which facilitates the energy management of multiple energy storage modules 110, reduces the coupling influence between components, and simplifies system control.

[0068] In some embodiments, the first DC / DC converter 140 includes a first terminal, a second terminal, a third terminal, and a fourth terminal.

[0069] In this embodiment, the high-voltage side of the first DC / DC converter 140 may include a first terminal and a second terminal, and the low-voltage side of the first DC / DC converter 140 may include a third terminal and a fourth terminal.

[0070] The first end can be connected to the positive busbar of the high-voltage busbar, and the second end can be connected to the negative busbar of the high-voltage busbar.

[0071] The third end can be connected to each energy storage module 110 via the positive busbar of the low-voltage busbar, and the fourth end can be connected to each energy storage module 110 via the negative busbar of the low-voltage busbar.

[0072] The connection method of the first, second, third and fourth terminals can form a four-wire connection, which can ensure independent control of the positive and negative buses and improve the stability of energy transmission.

[0073] In some embodiments, the first DC / DC converter 140 may be a bidirectional DC / DC converter.

[0074] In this embodiment, the bidirectional DC / DC converter can realize bidirectional energy flow between the high-voltage bus and the low-voltage bus. For example, when the battery is charging, energy flows from the high-voltage bus to the low-voltage bus, and when the battery is discharging, energy flows from the low-voltage bus to the high-voltage bus.

[0075] For example, when the new energy power generation device generates enough electricity, or when the grid needs energy storage, the high voltage of the high voltage bus is stepped down to the voltage of the low voltage bus by the first DC / DC converter 140, which can charge the energy storage module 110.

[0076] When the power generation of the new energy power generation device is insufficient or when grid connection is required, the low voltage of the low voltage bus can be boosted to the voltage of the high voltage bus by the first DC / DC converter 140, so as to supply power to the inverter module 120 for grid connection or directly to the high voltage load.

[0077] In some embodiments, the first DC / DC converter 140 may be an isolated converter.

[0078] In this embodiment, the first DC / DC converter 140 can adopt an isolated converter structure (such as flyback, forward, or full-bridge isolated topology) to achieve electrical isolation between the high-voltage side and the low-voltage side, which can prevent high-voltage side faults from affecting low-voltage side equipment and improve system safety.

[0079] In some embodiments, the first DC / DC converter 140 may be configured for fixed gain control.

[0080] In this embodiment, by presetting a fixed voltage conversion ratio (gain), the dynamic relationship between the output voltage and the input voltage can be linearized, thereby reducing the complexity of the feedback control loop and reducing the need for dynamic adjustment.

[0081] An isolated bidirectional DC / DC converter achieves electrical isolation between input and output through a transformer. The voltage conversion ratio (gain) can be determined by both the transformer turns ratio and the duty cycle of the switching transistor.

[0082] Fixed gain control enables the design of a voltage regulation loop for the bus voltage, facilitating system loop voltage regulation.

[0083] Continue to refer to Figure 1 In some embodiments, the energy storage system may further include a first capacitor C1.

[0084] In this embodiment, the first capacitor C1 is connected in parallel with the third and fourth terminals.

[0085] Connecting a first capacitor C1 in parallel between the positive and negative busbars of the low-voltage busbar can suppress voltage fluctuations and filter out high-frequency noise.

[0086] The capacitance value of the first capacitor C1 can be selected according to the voltage level and load characteristics of the low-voltage bus, which can ensure the voltage stability of the low-voltage bus.

[0087] In some embodiments, the energy storage system may further include a second capacitor C2.

[0088] In this embodiment, the second capacitor C2 is connected in parallel with the first terminal and the second terminal.

[0089] The second capacitor C2 can be connected in parallel between the positive and negative busbars of the high-voltage busbar.

[0090] In some embodiments, the energy storage module 110 may include a second DC / DC converter 150 and a battery pack 160.

[0091] In this embodiment, one end of the second DC / DC converter 150 is connected to the other end of the first DC / DC converter 140.

[0092] The battery pack 160 can be connected to the other end of the second DC / DC converter 150.

[0093] The second DC / DC converter 150 is an energy conversion unit that connects the low-voltage bus to the battery pack 160.

[0094] The second DC / DC converter 150 can convert the voltage of the low-voltage bus to a voltage that matches the battery pack 160, or reverse the voltage of the battery pack 160 to the voltage of the low-voltage bus, thereby enabling the charging and discharging of the battery pack 160.

[0095] The second DC / DC converter 150 can be a bidirectional DC / DC converter. When the battery pack 160 is charging, the second DC / DC converter 150 can operate in buck mode, and energy flows from the low-voltage bus to the battery pack 160. When the battery pack 160 is discharging, the second DC / DC converter 150 can operate in boost mode, and energy flows from the battery pack 160 to the low-voltage bus.

[0096] The second DC / DC converter 150 can adopt a non-isolated topology (such as a Buck-Boost converter), which is suitable for direct connection between the low-voltage side and the low-voltage bus, and the voltage level difference between the two is small, so no additional isolation is required.

[0097] For example, in this application, the voltage characteristic value of the low-voltage bus can be less than 60V, and the output voltage of the battery pack 160 can be less than the first voltage threshold (e.g., 10V).

[0098] The low-voltage battery pack 160 has a lower cost; for example, the low-voltage battery pack 160 can be configured with 314AH cells.

[0099] Battery pack 160 can use lithium-ion batteries or lead-acid batteries, etc.

[0100] The required energy capacity can be achieved by connecting individual cells in series and parallel to store energy, which can reduce the cost of a single cell.

[0101] For example, the voltage of a single battery cell is typically 3.2V to 4.2V, and it can be connected in series or parallel to achieve the rated voltage (such as 10V).

[0102] In this application, an energy storage system is constructed based on a low-voltage battery pack 160, thereby reducing the cost of the energy storage system.

[0103] like Figure 1 As shown, in some embodiments, the inverter module 120 may further include a DC / AC converter 170.

[0104] In this embodiment, one end of the DC / AC converter 170 can be connected to one end (high-voltage side) of the first DC / DC converter 140 via a high-voltage bus, and the other end of the DC / AC converter 170 can be configured to connect to the power grid (such as a 220V / 380V AC power grid, e.g.) Figure 1 (As shown on the AC side).

[0105] The DC / AC converter 170 is used to convert the DC power from the high-voltage bus into AC power that is in phase and frequency with the power grid, thereby enabling grid connection.

[0106] The DC / AC converter 170 can be configured as a single-phase or three-phase unit and has grid-connection control to ensure that the harmonic content of the grid-connected current meets the standards.

[0107] The DC / AC converter 170 can directly utilize the high stability of the high-voltage bus to reduce the impact of voltage fluctuations in the inverter stage.

[0108] During the research and development process, the inventors discovered that in traditional single-bus systems, the transmission of new energy power generation devices to the grid requires multiple stages, resulting in a long transmission path and significant losses. Furthermore, battery charging and discharging directly affect the inverter input through the low-voltage bus, leading to voltage fluctuations and additional losses.

[0109] In this application, by simplifying the inverter module 120, the energy of the new energy power generation device can be directly transmitted to the grid through the high-voltage bus. While ensuring power safety, the efficiency of the inverter module 120 is improved, making the energy transmission of the grid connection path more efficient and reducing the energy loss of the new energy power generation device when it is directly used. In addition, the battery is independently managed through the low-voltage bus, reducing intermediate conversion links and reducing losses.

[0110] In some embodiments, the first DC / DC converter 140 is configured to switch to the corresponding conversion direction according to the charging and discharging state of the energy storage module 110.

[0111] In this embodiment, the charging and discharging state of the energy storage module 110 may include a charging state or a discharging state.

[0112] When the new energy power generation device generates excess power, the energy storage module 110 can start the charging mode and adjust its own charging current (or charging power); when the new energy power generation device generates insufficient power, the energy storage module 110 can start the discharging mode and supply power to the inverter module 120.

[0113] When the energy storage module 110 needs to be charged, the first DC / DC converter 140 and the second DC / DC converter 150 can operate in buck mode. The actual charging power input to the energy storage module 110 can be adjusted by changing the duty cycle of the switching transistors and continuously modulated until the battery charging power limit of the energy storage module 110 is reached. The actual charging power is the power that actually flows from the new energy power generation device into the energy storage module 110.

[0114] When the new energy power generation device generates sufficient power, the boost module 130 boosts the low voltage output by the new energy power generation device to the high voltage bus (e.g., 400V). Part of the energy is connected to the grid via the DC / AC converter 170; the other part of the energy is stepped down to the low voltage bus (e.g., 48V) via the first DC / DC converter 140, and then stepped down to the battery pack 160 voltage (10V) via the second DC / DC converter 150 to charge the battery pack 160. At this time, the first DC / DC converter 140 operates in step-down mode (high voltage → low voltage), and the second DC / DC converter 150 operates in step-down mode (low voltage bus → battery).

[0115] When the energy storage module 110 needs to discharge, the first DC / DC converter 140 and the second DC / DC converter 150 can operate in boost mode, and the energy storage module 110 can start to output power in reverse as a controlled current source. The current output from the energy storage module 110 to the inverter module 120 can be controlled by adjusting the duty cycle.

[0116] When the new energy power generation device generates insufficient power or there is no power generation at night, the battery pack 160 is boosted to the low-voltage bus (e.g., 10V→48V) by the second DC / DC converter 150, and then boosted to the high-voltage bus (48V→400V) by the first DC / DC converter 140. Finally, it is connected to the grid or supplies power to high-voltage loads through the DC / AC converter 170. At this time, the first DC / DC converter 140 operates in boost mode (low voltage→high voltage), and the second DC / DC converter 150 operates in boost mode (battery→low voltage bus).

[0117] In some embodiments, the energy storage system can support multiple combinations.

[0118] In this embodiment, for example, the energy storage system can support three combined forms to meet the needs of different scenarios:

[0119] The inverter module 120 may include a boost module 130, a DC / AC converter 170, and a first DC / DC converter 140. The simple inverter product can realize the grid connection function of energy transmission from the new energy power generation device to the grid. The high-voltage bus has no direct output interface, ensuring power safety.

[0120] The energy storage module 110 may include a second DC / DC converter 150 and a battery pack 160. The energy storage module 110 can be used as an independent battery unit. After being coupled with the inverter module 120 through an interface, it forms an energy storage system and supports stacking expansion (such as stacking multiple energy storage modules 110), which conforms to the user's "stacked" usage habits.

[0121] The integrated energy storage unit may include: a boost module 130, a DC / AC converter 170, a first DC / DC converter 140, a second DC / DC converter 150, and a battery pack 160. It can integrate all functions and can expand the capacity of the integrated unit by stacking additional energy storage modules 110, thus providing greater flexibility.

[0122] This application also provides an inverter system, including a boost module 130 and a first DC / DC converter 140.

[0123] In this embodiment, one end of the first DC / DC converter 140 is connected to the high-voltage bus of the inverter system, and is connected to the boost module 130 via the high-voltage bus.

[0124] The other end of the first DC / DC converter 140 is configured to be connected to each energy storage module 110 via a low-voltage bus.

[0125] The boost module 130 and the first DC / DC converter 140 can be combined into an inverter product. The inverter product can realize the grid connection function of transmitting energy from the new energy power generation device to the power grid. The high-voltage bus has no direct output interface, ensuring power safety.

[0126] In some embodiments, the inverter system may further include a DC / AC converter 170.

[0127] In this embodiment, one end of the DC / AC converter 170 is connected to one end of the first DC / AC converter 140 via a high-voltage bus, and the other end of the DC / AC converter 170 is configured to be connected to the power grid.

[0128] This application also provides an energy storage device, including a second DC / DC converter 150 and a battery pack 160.

[0129] In this embodiment, the energy storage device can be used as an independent battery unit, and can be coupled to the inverter module 120 through an interface to form an energy storage system.

[0130] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

[0131] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0132] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An energy storage system, characterized by, include: At least one set of energy storage modules; The inverter module includes a boost module and a first DC / DC converter. One end of the first DC / DC converter is connected to the high-voltage bus of the inverter module and is connected to the boost module via the high-voltage bus. The other end of the first DC / DC converter is connected to each of the energy storage modules via a low-voltage bus.

2. The energy storage system of claim 1, wherein, The first end of the first DC / DC converter is connected to the positive bus of the high-voltage bus, the second end is connected to the negative bus of the high-voltage bus, the third end is connected to each of the energy storage modules via the positive bus of the low-voltage bus, and the fourth end is connected to each of the energy storage modules via the negative bus of the low-voltage bus.

3. The energy storage system of claim 2, wherein, Also includes: A first capacitor is connected in parallel with the third and fourth terminals.

4. The energy storage system of any one of claims 1-3, wherein, The energy storage module includes: A second DC / DC converter, one end of which is connected to the other end of the first DC / DC converter; A battery pack is connected to the other end of the second DC / DC converter; the output voltage of the battery pack is less than a first voltage threshold.

5. The energy storage system of claim 1, wherein, The first DC / DC converter is an isolated converter.

6. The energy storage system of claim 1, wherein, The first DC / DC converter is a bidirectional DC / DC converter.

7. The energy storage system of any one of claims 1-3, wherein, The first DC / DC converter is configured to switch to the corresponding conversion direction according to the charging and discharging state of the energy storage module.

8. The energy storage system of claim 1, wherein, One end of the boost module is configured to connect to a new energy power generation device, and the other end of the boost module is connected to one end of the first DC / DC converter via the high-voltage bus.

9. The energy storage system of claim 1, wherein, The boost module is an isolated converter.

10. The energy storage system of any one of claims 1-3, wherein, The inverter module includes: A DC / AC converter, one end of which is connected to one end of the first DC / DC converter via the high-voltage bus, and the other end of which is configured to be connected to the power grid.

11. The energy storage system of any one of claims 1-3, wherein, The number of the at least one set of energy storage modules is multiple sets, and each set of energy storage modules is connected in parallel. Each set of energy storage modules is connected to the other end of the first DC / DC converter.

12. The energy storage system of any one of claims 1-3, wherein, The number of the at least one set of energy storage modules is one set.

13. An inverter system characterized by comprising: include: Boost module; A first DC / DC converter, one end of which is connected to the high-voltage bus of the inverter system and connected to the boost module via the high-voltage bus; the other end of the first DC / DC converter is configured to be connected to each energy storage module via a low-voltage bus.

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