Energy storage system

Abstract

The embodiment of the utility model provides an energy storage system, which comprises an interface, a first power compensation device and a second power compensation device, and is characterized in that the interface is electrically connected with an external power supply device; one end of the first power compensation device is electrically connected with the interface, and the other end of the first power compensation device is electrically connected with a capacitor; one end of the second power compensation device is electrically connected with the interface, and the other end of the second power compensation device is electrically connected with the battery device; wherein the first power compensation device and the second power compensation device are configured to provide reactive power and / or active power for the power supply device or absorb the reactive power and / or the active power according to a preset power priority. Based on the embodiment of the invention, the power supply stability of the power supply device can be improved.

Description

Technical Field

[0001] This application relates to the field of energy storage, and more specifically, to an energy storage system. Background Technology

[0002] In modern power systems, with the large-scale grid integration of renewable energy sources (such as wind and solar power) and increasingly complex load demands, grid stability and power quality face severe challenges. In energy storage systems, where bidirectional energy exchange occurs between the grid and battery devices, grid stability is crucial for building a robust modern power system. Therefore, improving grid stability is an urgent problem to be solved. Utility Model Content

[0003] This application provides an energy storage system that can improve the stability of power supply from an external power source.

[0004] In a first aspect, this application provides an energy storage system, including an interface, a first power compensation device, and a second power compensation device, wherein the interface is electrically connected to an external power supply device; the first power compensation device has one end electrically connected to the interface and the other end electrically connected to a capacitor; the second power compensation device has one end electrically connected to the interface and the other end electrically connected to a battery device; wherein the first power compensation device and the second power compensation device are configured to provide or absorb reactive power and / or active power to the power supply device according to a preset power priority.

[0005] In the embodiments of this application, since the first power compensation device can complement the second power compensation device electrically connected to the battery device, it can flexibly adapt to various power auxiliary service scenarios. Secondly, the first and second power compensation devices are configured to provide or absorb reactive power and / or active power to the power supply device according to a preset power priority, which can improve the efficiency of providing or absorbing reactive power and / or active power to the power supply device, thereby improving the stability of the power supply from the external power supply device. Furthermore, the dual-core grid system also has harmonic mitigation capabilities, which can reduce the risk of broadband oscillations.

[0006] The dual-core grid system refers to a system in which two power compensation devices with grid-building capabilities work together to build and support an external power supply device (such as a power grid or microgrid) through coordinated control. In the embodiments of this application, the dual-core grid system refers to the grid system formed by the first power compensation device and the second power compensation device.

[0007] In some embodiments, the first power compensation device is configured to provide or absorb reactive power to the power supply device in priority to provide or absorb active power to the power supply device based on capacitors; the second power compensation device is configured to provide or absorb active power to the power supply device based on battery devices in priority to reactive power.

[0008] In the embodiments of this application, the first power compensation device is configured to provide or absorb reactive power to the power supply device in priority over active power; the second power compensation device is configured to provide or absorb active power to the power supply device in priority over reactive power, which can maximize equipment utilization efficiency and response speed. In addition, when a disturbance occurs, the energy storage system can simultaneously, independently and to the maximum extent call up voltage regulation resources and frequency regulation resources, avoiding internal capacity contention and enhancing the stability and support capability of the energy storage system.

[0009] In some embodiments, the first power compensation device is configured to provide or absorb reactive power to the power supply device when the strength of the disturbance signal is below a first threshold; and / or, provide or absorb active power to the power supply device based on a capacitor; the first power compensation device and the second power compensation device are configured to provide or absorb reactive power and / or active power to the power supply device when the strength of the disturbance signal is greater than or equal to the first threshold; wherein the strength of the disturbance signal is determined according to the frequency and voltage of the power supply device.

[0010] In the embodiments of this application, when the strength of the disturbance signal is lower than a first threshold, the first power compensation device is configured to provide or absorb reactive power to the power supply device; and / or, provide or absorb active power to the power supply device based on a capacitor; when the strength of the disturbance signal is greater than or equal to the first threshold, the first power compensation device and the second power compensation device are configured to provide or absorb reactive power and / or active power to the power supply device. Voltage fluctuations in the power supply device require millisecond-level fast current response for compensation, and the first power compensation device can respond quickly. While frequency fluctuations and power fluctuations also require fast response, they often require more sustained energy support. By having the first power compensation device and the second power compensation device work together to compensate, a good dynamic response can be achieved, thereby improving the stability of the power supply from the external power supply device.

[0011] In some embodiments, the first power compensation device and the second power compensation device are configured to provide or absorb reactive power and / or active power to the power supply device when the short-circuit ratio of the power supply device is less than or equal to a second threshold and when the strength of the disturbance signal is greater than or equal to a first threshold; wherein the strength of the disturbance signal is determined according to the frequency and voltage of the power supply device.

[0012] In the scheme of this application embodiment, voltage and frequency decoupling and coordinated stability can be achieved under weak power grid conditions; in addition, the first power compensation device and the second power compensation device both operate in grid-connected mode and, as controlled voltage sources, can directly increase the equivalent short-circuit capacity of the access point.

[0013] In some embodiments, the capacitor is a double-layer capacitor.

[0014] In the embodiments of this application, because the double-layer capacitor has high power density, short response time, and longer cycle life, the first power compensation device electrically connected to it can complement the second power compensation device electrically connected to the battery device, thus flexibly adapting to various power auxiliary service scenarios. Secondly, the first and second power compensation devices are configured to provide or absorb reactive power and / or active power to the power supply device according to a preset power priority, which can improve the efficiency of providing or absorbing reactive power and / or active power to the power supply device, thereby improving the stability of the power supply from the external power supply device. Furthermore, the dual-core grid system also has harmonic mitigation capabilities, which can reduce the risk of broadband oscillations.

[0015] In some embodiments, the energy storage system further includes a controller for controlling the first power compensation device and the second power compensation device to provide or absorb reactive power and / or active power to the power supply device according to a preset power priority.

[0016] In the scheme of this application embodiment, a controller is used to configure the first power compensation device and the second power compensation device to provide or absorb reactive power and / or active power to the power supply device according to a preset power priority. Since the first power compensation device, which is electrically connected to the capacitor, can complement the second power compensation device, which is electrically connected to the battery device, it can flexibly adapt to various power auxiliary service scenarios. Secondly, configuring the first power compensation device and the second power compensation device to provide or absorb reactive power and / or active power to the power supply device according to the preset power priority can improve the efficiency of providing or absorbing reactive power and / or active power to the power supply device, thereby improving the stability of the power supply from the external power supply device. In addition, the dual-core grid system also has harmonic mitigation capabilities, reducing the risk of broadband oscillations.

[0017] In some embodiments, the interface is a busbar, one end of which is electrically connected to a power supply device and the other end is electrically connected to a first power compensation device and a second power compensation device; wherein, the power supply device is used to obtain external power, and the busbar is used to distribute the external power to the first power compensation device and / or the second power compensation device.

[0018] In the scheme of this application embodiment, the interface is a busbar. The busbar is used for the electrical connection between the first power compensation device and the second power compensation device and the power supply device, so that while the power supply device provides power to the first power compensation device and the second power compensation device, in the case of unstable power supply device, the first power compensation device and / or the second power compensation device can first provide or absorb active or reactive power to the power grid, so as to improve the stability and reliability of the power supply device.

[0019] In some embodiments, the first power compensation device includes a first modulator and a voltage source converter; wherein the first modulator is used to adjust the voltage phase and / or amplitude of the voltage source converter to provide or absorb reactive power and / or active power to the power supply device.

[0020] In the embodiments of this application, the voltage phase and / or amplitude of the voltage source converter are adjusted by the first regulator in the first power compensation device, thereby providing or absorbing reactive power and / or active power to the power supply device, so as to improve the stability and reliability of the power supply device.

[0021] In some embodiments, the second power compensation device includes a plurality of first sub-power compensation devices, which are connected in parallel; the first sub-power compensation device includes a plurality of second sub-power compensation devices, which are connected in series.

[0022] In the scheme of this application embodiment, multiple first sub-power compensation devices are connected in parallel, and the total output power is the sum of the output power of each first sub-power compensation device, which meets the large capacity requirements. Furthermore, in the event of a failure of a single first sub-power compensation device, the other first sub-power compensation devices can continue to operate, improving the stability of the energy storage system. Additionally, multiple second sub-power compensation devices are connected in series, which can adapt to different grid voltage levels and flexibly respond to various scenarios with different grid voltage levels. Attached Figure Description

[0023] Figure 1 A partial structural schematic diagram of a battery device provided in an embodiment of this application is shown.

[0024] Figure 2 A schematic diagram of the structure of an energy storage system provided in an embodiment of this application is shown.

[0025] Figure 3 A schematic diagram of another energy storage system provided in an embodiment of this application is shown.

[0026] Figure 4 A schematic diagram of another energy storage system provided in an embodiment of this application is shown.

[0027] Figure 5 A schematic diagram of another energy storage system provided in an embodiment of this application is shown.

[0028] Figure 6 A schematic diagram of another energy storage system provided in an embodiment of this application is shown.

[0029] Figure label:

[0030] Energy storage system 100; battery device 110; housing 11; first housing section 111; second housing section 112; battery cell 12; interface 120; power supply device 101; first power compensation device 102; second power compensation device 103; capacitor 140; controller 104; power grid 1011; bus 1012; first modulator 1021; voltage source converter 1022; first sub-power compensation device 1034; second sub-power compensation device 1035. Detailed Implementation

[0031] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to illustrate the principles of this application by way of example, but should not be used to limit the scope of this application, that is, this application is not limited to the described embodiments.

[0032] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, rather than to describe a specific order or hierarchy.

[0033] The directional terms used in the following description refer to the directions shown in the figures and are not intended to limit the specific structure of this application. It should also be noted in the description of this application that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0035] In this application, "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0036] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0037] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0038] Unless otherwise specified, all steps of this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0039] The battery apparatus mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells connected in series, parallel, or mixed connections via a busbar.

[0040] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells.

[0041] As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module. As another example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0042] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cells housed within the housing.

[0043] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0044] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0045] As an example, the enclosure may include a first enclosure and a second enclosure. The first enclosure and the second enclosure are fastened together to form a closed space inside the enclosure to house the individual battery cells. Here, "closed" refers to covering or closing, and can be either sealed or unsealed. The first enclosure may be a top cover or a bottom plate.

[0046] As an example, the enclosure may include a top cover, a frame, and a bottom plate. The top cover and bottom plate are connected to the frame, creating an enclosed space inside the enclosure to house the individual battery cells.

[0047] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0048] This application provides an energy storage device including one or more battery clusters to increase the voltage and capacity of the energy storage device. The battery cluster may include multiple battery devices, which are connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0049] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, an energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage system provided in this application embodiment can be any power system that requires energy storage devices.

[0050] In some embodiments, the energy storage device is an energy storage container or an energy storage cabinet.

[0051] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet.

[0052] In some embodiments, the energy storage device may include modules such as a thermal management module, a main control module, a central control module, a power distribution module, and a fire protection module.

[0053] As an example, the thermal management module may include a liquid cooling unit that supplies coolant to each battery device via piping to regulate the temperature of the individual battery cells.

[0054] As an example, the main control module can serve as the battery management unit for the battery cluster, used to monitor and manage the battery cluster. The main control module can monitor information such as the current, voltage, power, or temperature of the battery cluster. For instance, it can control the charging and discharging current and voltage of the battery cluster. The main control module includes modules such as an auxiliary battery management unit (SBMU) and a fusion switch.

[0055] As an example, the master control module can serve as the battery management unit for an energy storage device, used to monitor and manage the device. The master control module can monitor information such as the energy storage device's current, voltage, power, state of charge, or temperature. For instance, it can control the charging and discharging current and voltage of the energy storage device. As an example, the master control module may include modules such as an insulation monitoring module (IMM), a master battery management unit (MBMU), an Ethernet (ETH) module, and a fiber optic conversion module.

[0056] As an example, a fire protection system includes control panels, detectors, alarm devices, etc., used to detect, alarm, or extinguish fires in energy storage systems.

[0057] As an example, the power distribution unit can be used to distribute power to the power modules of the energy storage device.

[0058] In some embodiments, the energy storage system may include one or more energy storage devices and a power converter system (PCS), the power converter being connected between the power generation device and the energy storage device. The power generation device generates electrical energy, which can be stored in the energy storage device via the power converter. For example, the power generation device may specifically be a solar panel, hydroelectric power generation equipment, thermal power generation equipment, wind power generation equipment, etc. The specific type of power generation device is not limited in this application.

[0059] This application provides a charging network including a charging pile and an energy storage device. The charging pile is electrically connected to the energy storage device, which provides power to the charging pile. The charging pile is electrically connected to a battery device in the energy storage device via a cable, and the battery device can provide its stored electrical energy to the charging pile. The charging pile has one or more connectors for connecting to electrical equipment (such as a vehicle), thereby enabling the charging equipment to be recharged.

[0060] Currently, in energy storage systems, the power grid experiences voltage or power fluctuations due to external environmental interference or load changes, leading to grid instability. Energy storage systems need to provide active or reactive power to the power grid to reduce grid fluctuations and improve grid stability.

[0061] In energy storage systems, active and reactive power compensation to the power grid is usually achieved through PCS (Power Control System) within the energy storage system. However, setting up a large number of PCS for active and reactive power compensation is costly, and in the event of a PCS failure, neither active nor reactive power compensation can be performed, which is detrimental to the stability of the power grid.

[0062] Based on the above considerations, to improve grid stability, this application provides an energy storage system, including an interface, a first power compensation device, and a second power compensation device. The interface is electrically connected to an external power supply device. The first power compensation device is electrically connected at one end to the interface and at the other end to a capacitor. The second power compensation device is electrically connected at one end to the interface and at the other end to a battery device. The first and second power compensation devices are configured to provide or absorb reactive power and / or active power to the power supply device according to a preset power priority. Since the first power compensation device can complement the second power compensation device electrically connected to the battery device, it can flexibly adapt to various power auxiliary service scenarios. Furthermore, the configuration of the first and second power compensation devices to provide or absorb reactive power and / or active power to the power supply device according to a preset power priority can improve the efficiency of providing or absorbing reactive power and / or active power to the power supply device, thereby improving the stability of the power supply from the external power supply device. In addition, the dual-core grid system also has harmonic mitigation capabilities, which can reduce the risk of broadband oscillations.

[0063] The dual-core grid system refers to a system in which two power compensation devices with grid-building capabilities work together to build and support an external power supply device (such as a power grid or microgrid) through coordinated control. In the embodiments of this application, the dual-core grid system refers to the grid system formed by the first power compensation device and the second power compensation device.

[0064] Figure 1 A partial structural schematic diagram of a battery device 110 provided in an embodiment of this application is shown. For example... Figure 1 As shown, the battery device 110 of this application embodiment may include a plurality of battery cells 12 to meet different power usage requirements. The shape of the battery cell 12 in this application embodiment can be set according to actual application. For example, the battery cell 12 may be cylindrical, or it may be... Figure 1 The embodiments shown may be cuboids or other shapes, but are not limited to these.

[0065] It should be understood that, such as Figure 1 As shown, the battery device 110 of this embodiment may further include a housing 11, which can be used to accommodate multiple battery cells 12. The housing 11 of this embodiment has a hollow interior, and the multiple battery cells 12 are accommodated within the housing 11. The housing 11 may include two parts, referred to herein as a first housing portion 111 and a second housing portion 112, which are fastened together. The shapes of the first housing portion 111 and the second housing portion 112 can be determined according to the shape of the components housed inside, for example, according to the shape of the combination of the multiple battery cells 12 housed inside. At least one of the first housing portion 111 and the second housing portion 112 has an opening. For example, as... Figure 1 As shown, the first housing portion 111 and the second housing portion 112 can both be hollow cuboids with one open side each. The openings of the first housing portion 111 and the second housing portion 112 are opposite to each other, and the first housing portion 111 and the second housing portion 112 are interlocked to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 12. The multiple battery cells 12 are connected in parallel, series, or mixed and placed inside the housing 11 formed by the interlocking of the first housing portion 111 and the second housing portion 112.

[0066] For example, unlike Figure 1 As shown, either the first housing portion 111 or the second housing portion 112 may have only one hollow cuboid with an opening, while the other is plate-shaped to cover the opening. Taking the second housing portion 112 as a hollow cuboid with one opening, and the first housing portion 111 as a plate-shaped example, then the first housing portion 111 covers the opening of the second housing portion 112 to form a housing 11 with a closed chamber, which can be used to accommodate multiple battery cells 12.

[0067] Figure 2 A schematic diagram of the structure of an energy storage system 100 provided in an embodiment of this application is shown.

[0068] According to some embodiments of this application, such as Figure 2 As shown, the energy storage system 100 includes an interface 120, a first power compensation device 102, and a second power compensation device 103. The interface 120 is electrically connected to an external power supply device 101. The first power compensation device 102 is electrically connected at one end to the interface 120 and at the other end to a capacitor 140. The second power compensation device 103 is electrically connected at one end to the interface 120 and at the other end to a battery device 110. The first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101 according to a preset power priority.

[0069] The first power compensation device 102 can be a Static Var Generator (SVG), and the second power compensation device 103 can be a PCS. The SVG has a response speed of up to 3ms, enabling it to quickly provide reactive power to the grid 1011 to compensate for grid 1011 and improve its stability. Furthermore, the SVG can output capacitive or inductive reactive power without step-by-step adjustment. The SVG's output current THD is <3%. It can accurately compensate for reactive power, improving the stability of the grid 1011. Additionally, with a large number of second power compensation devices 103, circulating current and oscillation problems between devices are difficult to avoid. Increasing the number of SVGs can reduce these problems.

[0070] It should be understood that the power supply device 101 can provide power to the first power compensation device 102 and the second power compensation device 103 through the interface 120. Specifically, the power supply device 101 can be electrically connected to the second power compensation device 103, which can realize energy transfer and interaction between the power supply device 101 and the battery device 110. The battery device 110 can be charged, that is, absorb electrical energy from the power supply device 101; the battery device 110 can also be discharged, that is, the battery device 110 releases electrical energy to the power supply device 101.

[0071] It should be understood that the first power compensation device 102 and / or the second power compensation device 103 provide or absorb reactive or active power from the power supply device 101 because, for example, when the power supply device 101 is affected by external environmental interference or sudden load changes, the power of the power grid becomes unbalanced. The energy storage system 100 needs to stabilize the power grid by regulating its frequency or voltage. Specifically, frequency regulation or voltage regulation means providing active or reactive power to the power grid for compensation. Alternatively, in the embodiments of this application, unless otherwise specified, the first power compensation device 102 and / or the second power compensation device 103 are both configured in a grid-connected mode.

[0072] It should also be understood that there can be multiple first power compensation devices 102, which can be connected in parallel, in series, or in a mixed series-parallel connection; there can also be multiple second power compensation devices 103, which can be connected in parallel, in series, or in a mixed series-parallel connection. This application does not impose any limitations on this.

[0073] It should also be understood that the power supply device 101 may include the power grid, or other equipment or devices that provide power to the energy storage system 100, and this application does not limit it in any way. The interface 120 may be a busbar for electrically connecting the power supply device 101 with the first power compensation device 102 and the second power compensation device 103. The interface 120 may also be a pre-charge circuit, etc., and this application does not limit it in any way.

[0074] In the embodiments of this application, the preset power priority can be a rule-based strategy based on sequence or condition judgment.

[0075] For example, the first power compensation device 102 can first use its full capacity to meet its priority type of power demand (reactive power). If there is remaining capacity, it can then be used to meet the secondary type (active power). Simultaneously, the second power compensation device 103 can first use its full capacity to meet its priority type of power demand (active power). If there is remaining capacity, it can then be used to meet the secondary type (reactive power). For instance, if the power supply device 101 requires reactive power Q of 5 and active power P of 10, the first power compensation device 102 can provide 5 units of reactive power, and its remaining active power capacity is assumed to be 3. The second power compensation device 103 provides 10 units of active power. The second power compensation device 103 first uses its full 8 units of capacity to provide active power, leaving a 2-unit active power deficit. This deficit can be filled by utilizing the remaining active power capacity of the first power compensation device 102. It should be understood that the unit of active power can be watts, and the unit of reactive power can be volt-amperes.

[0076] For example, output thresholds or triggering conditions for secondary power types can be set for the first power compensation device 102 and the second power compensation device 103. Secondary power output is only permitted when the demand for its primary power type falls below a certain value. For instance, it can be set to only allow reactive power output when the active power output of the second power compensation device 103 is below 20% of its rated capacity. Or, the second power compensation device 103 can be instructed to initiate reactive power output only when the reactive power output of the first power compensation device 102 reaches 80% or more of its capacity.

[0077] In the embodiments of this application, the preset power priority can also be a collaborative allocation strategy based on optimized calculation.

[0078] For example, the power allocation problem can be structured as an optimization problem (such as minimizing total losses, minimizing equipment aging, or maximizing specific gains). In the objective function or constraints, higher weighting coefficients or more lenient constraints are assigned to the active power output of the second power compensation device 103 and the reactive power output of the first power compensation device 102, while lower weighting or more stringent constraints (such as capacity limits) are assigned to their secondary outputs.

[0079] In the embodiments of this application, the first power compensation device 102 can complement the second power compensation device 103, which is electrically connected to the battery device 110, and can flexibly adapt to various power auxiliary service scenarios. Secondly, the first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101 according to a preset power priority, which can improve the efficiency of providing or absorbing reactive power and / or active power to the power supply device 101, thereby improving the stability of the power supply from the external power supply device 101. In addition, the dual-core grid system also has harmonic mitigation capabilities, which can reduce the risk of broadband oscillations.

[0080] According to some embodiments of this application, optionally, such as Figure 2 As shown, the first power compensation device 102 is configured to provide or absorb reactive power to the power supply device 101 in priority to provide or absorb active power to the power supply device 101 based on the capacitor 140; the second power compensation device 103 is configured to provide or absorb active power to the power supply device 101 based on the battery device 110 in priority to provide or absorb reactive power.

[0081] The power supply device 101 can be electrically connected to the first power compensation device 102, which can realize energy transmission and interaction between the power supply device 101 and the capacitor 140. The capacitor 140 can be charged, that is, absorb electrical energy from the power supply device 101; the capacitor 140 can also be discharged, that is, the capacitor 140 releases electrical energy to the power supply device 101.

[0082] According to some embodiments of this application, the capacitor 140 may optionally be a double-layer capacitor.

[0083] The capacitor 140 can be a double-layer capacitor, also known as a supercapacitor. A supercapacitor is an energy storage device based on the principle of the double layer at the electrode-electrolyte interface and / or a rapid Faraday reaction. It has a power density and cycle life far exceeding that of a conventional battery device 110, and can achieve rapid charging and discharging at the second or even millisecond level. In this embodiment, the double-layer capacitor 140 serves as a power-type energy storage unit, working in conjunction with the first power compensation device 102 to provide instantaneous, highly dynamic active and reactive power support for the energy storage system 100. Unlike the conventional battery device 110, the energy storage process of a supercapacitor relies on physical electrostatic adsorption or a rapid surface redox reaction, without involving slow chemical reactions within the bulk phase. Therefore, it can respond to power commands within milliseconds, meeting the instantaneous power compensation requirements of the power grid 1011 while providing or absorbing large amounts of instantaneous power to smooth out power surges and oscillations.

[0084] It should be understood that in the embodiments of this application, any power-type energy storage device or fast-response energy storage unit with similar high power density and fast charging and discharging characteristics, such as flywheel energy storage system, superconducting magnetic energy storage system, etc., can replace the supercapacitor and be combined with the first power compensation device 102 to achieve the same instantaneous power support purpose.

[0085] In the embodiments of this application, because the double-layer capacitor has high power density, short response time, and longer cycle life, the first power compensation device 102 electrically connected to it can complement the second power compensation device 103 electrically connected to the battery device 110, which can flexibly adapt to various power auxiliary service scenarios. Secondly, the first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101 according to a preset power priority, which can improve the efficiency of providing or absorbing reactive power and / or active power to the power supply device 101, thereby improving the stability of the power supply from the external power supply device 101. In addition, the dual-core grid system also has harmonic mitigation capabilities, which can reduce the risk of broadband oscillations.

[0086] The first power compensation device 102 is configured to provide or absorb reactive power to the power supply device 101 prior to active power. In other words, the first power compensation device 102 primarily provides reactive power and secondarily provides active power. For example, when it is necessary to provide both active and reactive power to the power supply device 101 simultaneously, the first power compensation device 102 first provides reactive power, and then provides active power. Alternatively, the total capacity of the first power compensation device 102 is a fixed value. The configuration of the first power compensation device 102 to provide or absorb reactive power to the power supply device 101 prior to active power determines the order in which its capacity is used: first allocated to reactive power, and then the remainder to active power.

[0087] The second power compensation device 103 is configured to provide or absorb active power to the power supply device 101 in priority over reactive power. In other words, the second power compensation device 103 mainly provides active power and secondarily provides reactive power.

[0088] Among them, the dual-core grid system composed of the first power compensation device 102 and the second power compensation device 103 has a fast response speed. Since the supercapacitor can react quickly within milliseconds, when the frequency modulation command is received, the grid with the supercapacitor responds quickly and undertakes the primary frequency modulation task. Since the response time is faster and the frequency modulation effect is better, the grid corresponding to the battery device 110 is responsible for the secondary frequency modulation and peak shaving tasks.

[0089] In the scheme of this application embodiment, the first power compensation device 102 is configured to provide or absorb reactive power to the power supply device 101 in priority over active power; the second power compensation device 103 is configured to provide or absorb active power to the power supply device 101 in priority over reactive power, which can maximize the equipment utilization efficiency and response speed. In addition, when a disturbance occurs, the energy storage system 100 can simultaneously, independently and to the maximum extent call up voltage regulation resources and frequency regulation resources, avoiding internal capacity contention and enhancing the stability and support capability of the energy storage system 100.

[0090] According to some embodiments of this application, optionally, such as Figure 2 As shown, when the strength of the disturbance signal is lower than a first threshold, the first power compensation device 102 is configured to provide or absorb reactive power to the power supply device 101; and / or, provide or absorb active power to the power supply device 101 based on the capacitor 140; when the strength of the disturbance signal is greater than or equal to the first threshold, the first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101; wherein, the strength of the disturbance signal is determined according to the frequency and voltage of the power supply device 101.

[0091] When the strength of the disturbance signal is lower than the first threshold, i.e. when the power supply device 101 experiences a small disturbance, the first power compensation device 102 provides or absorbs reactive power and / or active power. At this time, the second power compensation device 103 can be in grid-following mode, and the first power compensation device 102 can be in grid-building mode. The grid-following mode refers to the mode in which the first power compensation device 102 or the second power compensation device 103 operates as a controlled current source, tracks the voltage of the grid 1011 through a phase-locked loop, and outputs power based on a given current command. The grid-building mode refers to the mode in which the first power compensation device 102 or the second power compensation device 103 operates as a voltage source, autonomously establishes and controls the voltage and frequency of the AC bus 1012.

[0092] In some embodiments, the configuration of the first power compensation device 102 to provide or absorb reactive power and / or active power to the power supply device 101 when the strength of the disturbance signal is lower than a first threshold refers to the situation where a small disturbance occurs in the power supply device 101. Specifically, a small disturbance refers to an abnormal state of the power grid 1011 caused by load switching, slight fluctuations in renewable energy power, etc., with low intensity and short duration. The small disturbance can be determined based on the voltage amplitude deviation, frequency deviation, disturbance frequency, and duration of the power grid 1011.

[0093] The first threshold can be determined based on the frequency, voltage, etc. of the power supply device 101, or in other words, the first threshold can be determined based on the strength of the disturbance signal of the power supply device 101. The first threshold can also be set based on empirical values ​​or actual conditions, and this application does not impose any limitations on this.

[0094] In some embodiments, the first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101 when the strength of the disturbance signal is greater than or equal to a first threshold. This refers to the situation where the power supply device 101 experiences a large disturbance. Specifically, a large disturbance refers to a fault or sudden change state that threatens the stability of the power grid 101 and requires the first power compensation device 102 and the second power compensation device 103 to provide maximum instantaneous power and continuous energy support.

[0095] In the embodiments of this application, the first power compensation device 102 is configured to provide or absorb reactive power to the power supply device 101 when the intensity of the disturbance signal is lower than a first threshold; the first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101 when the intensity of the disturbance signal is greater than or equal to the first threshold. Voltage fluctuations in the power supply device 101 require millisecond-level fast current response for compensation, and the first power compensation device 102 can respond quickly. While frequency fluctuations and power fluctuations also require fast response, they often require more sustained energy support. By having the first power compensation device 102 and the second power compensation device 103 work together to compensate, a good dynamic response can be achieved, thereby improving the stability of the power supply from the external power supply device 101.

[0096] According to some embodiments of this application, optionally, such as Figure 2 As shown, the first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101 when the short-circuit ratio of the power supply device 101 is less than or equal to the second threshold and when the strength of the disturbance signal is greater than or equal to the first threshold; wherein the strength of the disturbance signal is determined according to the frequency and voltage of the power supply device 101.

[0097] The short-circuit ratio being less than or equal to the second threshold refers to the case of a weak power grid. In this case, and when the strength of the disturbance signal is greater than or equal to the first threshold, both the first power compensation device 102 and the second power compensation device 103 are in the grid-forming mode.

[0098] Optionally, under strong grid conditions, i.e. when the short-circuit ratio is greater than the second threshold, and when the strength of the disturbance signal of the second power compensation device 103 is lower than the first threshold, the first power compensation device 102 and the second power compensation device 103 are configured to be in grid-following mode.

[0099] Among them, a strong power grid usually refers to a power grid with a high short-circuit ratio. For example, a power grid with a short-circuit ratio greater than 3 can be called a strong power grid. The short-circuit ratio is the ratio of the short-circuit capacity of the power grid to the rated capacity of the generating equipment connected to that point at a certain point of common coupling. The short-circuit capacity reflects the strength of the power grid at that point.

[0100] In other words, the smaller the system's equivalent impedance, the larger the short-circuit current, the larger the short-circuit capacity, and the stronger the power grid.

[0101] A weak power grid typically refers to a power grid with a low short-circuit ratio, such as a power grid with a short-circuit ratio of less than 2 or even close to 1.

[0102] It should be understood that the second threshold is determined based on the short-circuit ratio of the power grid, or it can be set based on actual conditions or empirical values.

[0103] It should also be understood that the second power compensation device 103 can set the system's reference frequency (e.g., 50Hz) and adjust the frequency according to power commands. When the load increases, the second power compensation device 103 increases active power output through a control algorithm to prevent frequency drops, thus providing virtual inertia and primary frequency regulation capability. The first power compensation device 102 directly counteracts voltage fluctuations caused by power flow by controlling the amplitude of its output voltage. In weak power grids, the first power compensation device 102 and the second power compensation device 103 work together; the second power compensation device 103 can adjust the frequency and provide active power, while the first power compensation device 102 can provide voltage.

[0104] In the scheme of this application embodiment, voltage and frequency decoupling and coordinated stability can be achieved under weak power grid conditions; in addition, the first power compensation device 102 and the second power compensation device 103 both operate in grid mode and, as controlled voltage sources, can directly increase the equivalent short-circuit capacity of the access point.

[0105] According to some embodiments of this application, optionally, the second power compensation device 103 is configured to be in network following mode when the strength of the disturbance signal is lower than a first threshold.

[0106] In the embodiment of this application, when the strength of the disturbance signal is lower than the first threshold, the second power compensation device 103 is configured to be in grid-following mode, which reduces the loss of the second power compensation device 103, can extend the service life of the PCS, and reduce operation and maintenance costs. In addition, when a small disturbance occurs, by having the first power compensation device 102 in grid-building mode and the second power compensation device 103 in grid-following mode, the control task is decoupled, which reduces the risk of oscillation or conflict that may occur when the two devices simultaneously control the voltage of the same bus 1012, thereby improving the stability of the power supply of the external power supply device 101.

[0107] Figure 3 A schematic diagram of the structure of another energy storage system 100 provided in an embodiment of this application is shown.

[0108] According to some embodiments of this application, optionally, such as Figure 3 As shown, the energy storage system 100 also includes a controller 104, which controls the first power compensation device 102 and the second power compensation device 103 to provide or absorb reactive power and / or active power to the power supply device 101 according to a preset power priority.

[0109] It should be understood that the controller 104 can control the first power compensation device 102 or the second power compensation device 103 based on the real-time detected voltage or power value of the power supply device 101. For example, when a voltage drop is detected in the power supply device 101, the controller 104 can control the first power compensation device 102 and / or the second power compensation device 103 to provide reactive power, thereby increasing the voltage of the power supply device 101. When a voltage rise is detected in the power supply device 101, the controller 104 can control the first power compensation device 102 and / or the second power compensation device 103 to absorb reactive power and reduce the voltage. Additionally, the controller 104 can also control based on other empirical values ​​or stored values; this application does not impose any limitations on this.

[0110] It should also be understood that the controller 104 may be an energy management system (EMS). The battery device 110 responds to the scheduling instructions of the power supply device 101 and participates in auxiliary services such as peak shaving, frequency regulation, and voltage support. The EMS is used to dynamically allocate the output of active and / or reactive power of the first power compensation device 102 and / or the second power compensation device 103 to ensure the stability and reliability of the energy storage system 100.

[0111] The controller 104 can communicate with the first power compensation device 102 and the second power compensation device 103 via Ethernet or Controller Area Network (CAN) cable, or via other means. This application does not impose any limitations on this.

[0112] It should also be understood that the controller 104 may include a first controller, a second controller and a third controller, wherein the first controller is the overall controller, the second controller may be set in the first power compensation device 102 for further controlling the first power compensation device 102 according to the instructions of the first controller, and the third controller may be set in the second power compensation device 103 for further controlling the second power compensation device 103 according to the instructions of the first controller.

[0113] Optionally, the second controller can control the first power compensation device 102 based on the voltage value of the power supply device 101, the reactive power command from the first controller, or the reactive power command obtained from local detection.

[0114] Optionally, the third controller can control the second rate compensation device based on the voltage or power value of the power supply device 101, the reactive power command from the first controller, or the active power command obtained from local detection.

[0115] In the embodiment of this application, a controller is used to configure the first power compensation device 102 and the second power compensation device 103 to provide or absorb reactive power and / or active power to the power supply device 101 according to a preset power priority. Since the double-layer capacitor has high power density, short response time, and longer cycle life, the first power compensation device 102, electrically connected to it, can complement the second power compensation device 103, electrically connected to the battery device 110, allowing for flexible adaptation to various power auxiliary service scenarios. Secondly, configuring the first power compensation device 102 and the second power compensation device 103 to provide or absorb reactive power and / or active power to the power supply device 101 according to a preset power priority can improve the efficiency of providing or absorbing reactive power and / or active power to the power supply device 101, thereby improving the stability of the power supply from the external power supply device 101. Furthermore, the dual-core grid system also features harmonic mitigation, reducing the risk of broadband oscillations.

[0116] Figure 4 A schematic diagram of another energy storage system 100 provided in an embodiment of this application is shown.

[0117] According to some embodiments of this application, optionally, such as Figure 4As shown, interface 120 is bus 1012. One end of bus 1012 is electrically connected to power supply device 101, and the other end is electrically connected to first power compensation device 102 and second power compensation device 103. Power supply device 101 is used to obtain external power, and bus 1012 is used to distribute external power to first power compensation device 102 and / or second power compensation device 103.

[0118] It should be understood that the power supply device 101 can be a power grid 1011, wherein the power grid 1011 is an energy input for the power interaction hub. When the energy storage system 100 is charging, the power grid 1011 provides electrical energy; when the energy storage system 100 is discharging, it feeds electrical energy to the power grid 1011. It should also be understood that the following embodiments can be described using the power grid 1011 as an example.

[0119] It should also be understood that bus 1012 is the main power distribution channel within the energy storage system 100. Based on voltage levels, it is divided into a DC bus and an AC bus. The DC bus sends the DC power from the battery to the PCS for conversion to AC power, or for reverse charging. The AC bus connects to the PCS, loads, and other equipment, distributing AC power.

[0120] In the embodiment of this application, interface 120 is bus 1012. Bus 1012 is used for electrical connection between the first power compensation device 102 and the second power compensation device 103 and the power supply device 101. This allows the power supply device 101 to provide power to the first power compensation device 102 and the second power compensation device 103. In the event of instability in the power supply device 101, the first power compensation device 102 and / or the second power compensation device 103 can first provide or absorb active or reactive power to the power grid 1011, thereby improving the stability and reliability of the power supply device 101.

[0121] Figure 5 A schematic diagram of another energy storage system 100 provided in an embodiment of this application is shown.

[0122] Optionally, based on some embodiments of this application, reference may be made to... Figures 2 to 5 The first power compensation device 102 includes a first modulator 1021 and a voltage source converter 1022; wherein, the first modulator 1021 is used to adjust the voltage phase and / or amplitude of the voltage source converter 1022 to provide or absorb reactive power and / or active power to the power supply device 101.

[0123] It should be understood that the first modulator 1021 can also be regarded as a device in the second controller. The first modulator 1021 generates a pulse width modulation signal, which is transmitted to the gate of the insulated gate bipolar transistor (IGBT) or metal-oxide-semiconductor field-effect transistor (MOSFET) of the inverter through an optical fiber or an isolated drive circuit, thereby adjusting the voltage phase of the voltage source converter 1022 to provide or absorb reactive power to the power supply device 101.

[0124] Optionally, the voltage source converter 1022 includes one or more IGBTs; wherein, the first modulator 1021 is used to generate switching signals for the IGBTs to regulate the opening and closing of the IGBTs, thereby regulating the voltage phase of the voltage source converter 1022.

[0125] It should be understood that the voltage source converter 1022 includes one or more insulated gate bipolar transistors (IGBTs), which may include the following:

[0126] In one scenario, the voltage source converter 1022 is a two-level inverter, with each phase consisting of two IGBTs forming a half-bridge, for a total of six IGBTs used in three phases.

[0127] In another scenario, the voltage source converter 1022 is a three-level inverter, with each phase including four IGBTs, forming an "H" bridge and outputting multi-level waveforms.

[0128] It should also be understood that the first modulator 1021 is used to generate switching signals for the IGBT to regulate the opening and closing of the IGBT 1023, thereby regulating the voltage phase of the inverter. Specifically, the first modulator 1021 generates precise switching signals for the IGBT, thereby controlling the IGBT's on and off states, thus regulating the phase and amplitude of the output current of the voltage source converter 1022, ultimately achieving reactive power output.

[0129] In the embodiment of this application, the voltage phase and / or amplitude of the voltage source converter 1022 is adjusted by the first regulator in the first power compensation device 102, thereby providing or absorbing reactive power and / or active power to the power supply device 101, so as to improve the stability and reliability of the power supply device 101.

[0130] According to some embodiments of this application, optionally, the second power compensation device 103 includes a bidirectional converter; wherein, when the battery device 110 is configured to charge and discharge, the bidirectional converter is used for energy conversion between the battery device 110 and the power supply device 101 to provide or absorb reactive power and / or active power to the power supply device 101.

[0131] Specifically, when the battery device 110 is configured to charge and discharge, the controller 104 controls the magnitude and direction of the active power transmitted between the bidirectional converter and the AC grid by adjusting the phase angle of the AC side output voltage of the bidirectional converter relative to the AC grid voltage; and the controller 104 controls the magnitude of the reactive power exchanged between the bidirectional converter and the AC grid by adjusting the amplitude of the AC side output voltage of the bidirectional converter.

[0132] In the embodiment of this application, the bidirectional converter in the second power compensation device 103 is used for energy conversion between the battery device 110 and the power supply device 101, so as to provide or absorb reactive power and / or active power to the power supply device 101, thereby realizing efficient and flexible energy interaction between the battery device 110 and the power grid 1011, and thus improving the stability of the power supply device 101.

[0133] Optionally, a transformer and a grid-connected switch may be installed between the second power compensation device 103 and the power grid 1011. One end of the grid-connected switch can be connected to the power supply device 101, and the other end can be connected to the transformer. One end of the transformer can be connected to the second power compensation device 103. The grid-connected switch includes a fuse unit and a load switch. The load switch is connected to the fuse unit. One end of the load unit is connected to the power supply device 101, and the other end is connected to the fuse unit. One end of the fuse unit is connected to the transformer.

[0134] Optionally, the first power compensation device 102 and the second power compensation device 103 can be connected to the booster station first, and then connected to the power supply device 101.

[0135] Figure 6 A schematic diagram of another energy storage system 100 provided in an embodiment of this application is shown.

[0136] According to some embodiments of this application, optionally, such as Figures 2 to 6 As shown, the second power compensation device 103 includes a plurality of first sub-power compensation devices 1034, which are connected in parallel; the first sub-power compensation devices 1034 include a plurality of second sub-power compensation devices 1035, which are connected in series.

[0137] In the scheme of this application embodiment, multiple first sub-power compensation devices 1034 are connected in parallel, and the total output power is the sum of the output power of each first sub-power compensation device 1034, which meets the large capacity requirements. In addition, if a single first sub-power compensation device 1034 fails, the other first sub-power compensation devices 1034 can continue to operate, which can improve the stability of the energy storage system 100. Furthermore, multiple second sub-power compensation devices 1035 are connected in series, which can adapt to different grid voltage levels and flexibly cope with various scenarios with different grid voltage levels.

[0138] According to some embodiments of this application, this application also provides an electrical device including an energy storage system 100 according to any of the above embodiments, the energy storage system 100 being used to store or provide electrical energy.

[0139] According to some embodiments of this application, see Figures 2 to 6 This application provides an energy storage system 100, including an interface 120, a first power compensation device 102, and a second power compensation device 103. The interface 120 is electrically connected to an external power supply device 101. The first power compensation device 102 is electrically connected at one end to the interface 120 and at the other end to a capacitor 140. The second power compensation device 103 is electrically connected at one end to the interface 120 and at the other end to a battery device 110. The first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101 according to a preset power priority.

[0140] The first power compensation device 102 is configured to provide or absorb reactive power to the power supply device 101 in priority to provide or absorb active power to the power supply device 101 based on the capacitor 140; the second power compensation device 103 is configured to provide or absorb active power to the power supply device 101 based on the battery device 110 in priority to provide or absorb reactive power.

[0141] When the strength of the disturbance signal is lower than a first threshold, the first power compensation device 102 is configured to provide or absorb reactive power to the power supply device 101; and / or, provide or absorb active power to the power supply device 101 based on the capacitor 140; when the strength of the disturbance signal is greater than or equal to the first threshold, the first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101; wherein the strength of the disturbance signal is determined according to the frequency and voltage of the power supply device 101.

[0142] When the short-circuit ratio of the power supply device 101 is less than or equal to a second threshold, and when the strength of the disturbance signal is greater than or equal to a first threshold, the first power compensation device 102 and the second power compensation device 103 are configured to provide or absorb reactive power and / or active power to the power supply device 101; wherein the strength of the disturbance signal is determined according to the frequency and voltage of the power supply device 101.

[0143] Capacitor 140 is a double-layer capacitor.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An energy storage system, characterized by, The energy storage system comprises: an interface (120) electrically connected to an external power supply device (101); a first power compensation device (102) having one end electrically connected to the interface (120) and the other end electrically connected to a capacitor (140); a second power compensation device (103) having one end electrically connected to the interface (120) and the other end electrically connected to a battery device (110); wherein the first power compensation device (102) and the second power compensation device (103) are configured to provide or absorb reactive power and / or active power to the power supply device (101) according to a preset power priority.

2. The energy storage system of claim 1, wherein, The first power compensation device (102) is configured to provide or absorb the reactive power to the power supply device (101) in priority to providing or absorbing the active power to the power supply device (101) based on the capacitor (140); The second power compensation device (103) is configured to provide or absorb the active power to the power supply device (101) in priority to the reactive power based on the battery device (110).

3. The energy storage system of claim 1, wherein, The first power compensation device (102) is configured to provide or absorb the reactive power to the power supply device (101) when the strength of a disturbance signal is lower than a first threshold value; and / or, provide or absorb the active power to the power supply device (101) based on the capacitor (140); The first power compensation device (102) and the second power compensation device (103) are configured to provide or absorb the reactive power and / or the active power to the power supply device (101) when the strength of the disturbance signal is greater than or equal to the first threshold value; wherein the strength of the disturbance signal is determined according to the frequency and voltage of the power supply device (101).

4. The energy storage system of claim 1, wherein, The first power compensation device (102) and the second power compensation device (103) are configured to provide or absorb the reactive power and / or the active power to the power supply device (101) when the short-circuit ratio of the power supply device (101) is less than or equal to a second threshold value and the strength of the disturbance signal is greater than or equal to the first threshold value; wherein the strength of the disturbance signal is determined according to the frequency and voltage of the power supply device (101).

5. The energy storage system of claim 1, wherein, The capacitor (140) is a double-layer capacitor.

6. The energy storage system of any one of claims 1-4, wherein, The energy storage system further comprises: a controller (104) for controlling the first power compensation device (102) and the second power compensation device (103) to be configured to provide or absorb the reactive power and / or the active power to the power supply device (101) according to the preset power priority.

7. The energy storage system of any one of claims 1-4, wherein, The interface (120) is a busbar (1012) having one end electrically connected to the power supply device (101) and the other end electrically connected to the first power compensation device (102) and the second power compensation device (103); wherein the power supply device (101) is configured to obtain an external power source, and the busbar (1012) is configured to distribute the external power source to the first power compensation device (102) and / or the second power compensation device (103).

8. The energy storage system of any one of claims 1-4, wherein, The first power compensation device (102) comprises a first modulator (1021) and a voltage source converter (1022); The first modulator (1021) is configured to adjust the voltage phase and / or amplitude of the voltage source converter (1022) to provide or absorb the reactive power and / or the active power to the power supply device (101).

9. The energy storage system of any one of claims 1-4, wherein, The second power compensation device (103) comprises a plurality of first sub-power compensation devices (1034), and the first sub-power compensation devices (1034) are connected in parallel. The first sub-power compensation device (1034) comprises a plurality of second sub-power compensation devices (1035), and the second sub-power compensation devices (1035) are connected in series.

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