Energy storage system, control method of energy storage system and energy storage cabinet

Abstract

This application relates to the field of energy storage, disclosing an energy storage system, a control method for the energy storage system, and an energy storage cabinet. A static transfer switch directly collects the real-time power value of the load and transmits it to an energy storage converter. The energy storage converter directly adjusts its output power value in real time based on the real-time power value of the load transmitted by the static transfer switch. This direct and rapid data interaction between the static transfer switch and the energy storage converter effectively shortens the transmission path of the real-time power value of the load, reducing the response time of the energy storage system to load power fluctuations from hundreds of milliseconds to tens of milliseconds. This significantly improves the response speed of the energy storage converter to load power fluctuations, enabling the energy storage system to quickly track load power fluctuations and reduce the risk of reverse current. Furthermore, this energy storage system can more fully utilize new energy sources, reduce the consumption of grid power, and save on electricity costs.

Description

Technical Field

[0001] This application relates to the field of energy storage, and in particular to an energy storage system, a control method for the energy storage system, and an energy storage cabinet. Background Technology

[0002] Currently, most medium- and low-voltage power distribution networks are unidirectional power supply networks. Their protection devices, lines, transformers, and other equipment are designed for unidirectional power flow from the grid (G) to the load. Reverse power flow can lead to local voltage exceeding limits in the power system, malfunctions of protection devices, overloads of lines or transformers affecting their service life, and even personal safety issues. Therefore, many countries and regions have established standards requiring electrochemical energy storage systems or photovoltaic power generation systems to have reverse power flow protection at their grid connection points, i.e., anti-reverse current protection.

[0003] In existing technologies, such as Figure 1 As shown, Figure 1This is a schematic diagram of an existing photovoltaic energy storage cabinet. The photovoltaic energy storage cabinet includes: an Energy Management System (EMS), a Power Conversion System (PCS), a Static Transfer Switch (STS), and a Maximum Power Point Tracking (MPPT). The Energy Management System is connected to the Battery Management System (BMS), the PV MPPT, the Power Conversion System, the Load Wattmeter (LWM), and the Grid Watt Meter (GWM). The PV MPPT is also connected to the Photovoltaic (PV) panels and the Power Conversion System. The Power Conversion System is also connected to the Battery (BAT) clusters and the Static Transfer Switch. The Static Transfer Switch is also connected to the load (LOAD) and the grid connection point, which is connected to the power grid. A load-side wattmeter is installed on the load side of the energy storage cabinet to detect the real-time power value of the load and transmits this value to the energy management subsystem. The battery management subsystem then transmits the current remaining charge and maximum discharge power of the battery clusters to the energy management subsystem. The energy management subsystem combines the real-time load power value, the current remaining charge and maximum discharge power of the battery clusters to schedule the energy storage converter, enabling the converter to track load fluctuations in real time and achieve anti-reverse current protection. This anti-reverse current scheme uses a load-side wattmeter to collect load power and the energy management subsystem to schedule the energy storage converter. The entire data link is long; the response time from the load-side wattmeter collecting load power to the energy storage converter tracking the load power is over several hundred milliseconds. When load fluctuations are frequent, the anti-reverse current protection effect is poor. To achieve better anti-reverse current protection, the energy storage converter only follows 70%-80% of the load power, absorbing the remaining power from the grid. This results in higher grid power consumption and increased user costs. Summary of the Invention

[0004] The embodiments of this application aim to provide an energy storage system, a control method for the energy storage system, and an energy storage cabinet, which can solve the problems of slow response speed, poor anti-reverse current effect, and low utilization rate of new energy power in existing anti-reverse current schemes when the load fluctuates frequently.

[0005] To address the aforementioned technical problems, the first aspect of this application provides an energy storage system, which includes an energy storage converter and a static transfer switch; The energy storage converter is connected to the battery cluster via a DC bus. The static transfer switch is connected to the energy storage converter, the load, and the grid connection point, respectively. The grid connection point is connected to the power grid. The battery clusters are used for storing electrical energy; The static transfer switch is used to collect the real-time power value of the load and transmit it to the energy storage converter. The energy storage converter is used to adjust its own output power value in real time according to the real-time power value of the received load.

[0006] Optionally, the energy storage converter is also connected to a battery management subsystem, which is used to collect the current remaining power and maximum discharge power of the battery cluster and transmit them to the energy storage converter. The energy storage converter is used to adjust its output power in real time according to the received real-time power value of the load, including: The energy storage converter is used to adjust its output power value in real time according to the real-time power value of the load and the current remaining power and maximum discharge power of the battery cluster.

[0007] Optionally, the energy storage system further includes a photovoltaic maximum power tracker, which is connected to the photovoltaic panel and the DC bus respectively, for tracking the maximum power of photovoltaic power generation.

[0008] Optionally, the photovoltaic maximum power tracker is also connected to the energy storage converter to transmit the real-time power value of photovoltaic power generation to the energy storage converter; The energy storage converter is used to adjust its output power in real time according to the received real-time power value of the load, including: The energy storage converter is used to adjust its output power value in real time according to the real-time power value of the load, the current remaining power and maximum discharge power of the battery cluster, and the real-time power value of the photovoltaic power generation.

[0009] Optionally, the energy storage converter and the static transfer switch are connected via a controller area network (CAN) or RS485 serial differential communication (Recommended Standard 485, RS485).

[0010] Optionally, the static transfer switch is also used to collect the voltage value of the power grid and determine whether the energy storage system is connected to or disconnected from the grid based on the collected voltage value of the power grid.

[0011] A second aspect of this application also provides a control method for an energy storage system, applied to an energy storage system including an energy storage converter and a static transfer switch. The energy storage converter is connected to a battery cluster via a DC bus. The static transfer switch is connected to the energy storage converter, a load, and a grid connection point, respectively. The grid connection point is connected to the power grid. The control method includes: The static transfer switch collects the real-time power value of the load and transmits it to the energy storage converter; The energy storage converter adjusts its output power in real time according to the real-time power value of the load.

[0012] Optionally, the energy storage converter is also connected to a battery management subsystem; the control method further includes, before the energy storage converter adjusts its output power value in real time according to the real-time power value of the load: The battery management subsystem collects the current remaining power and maximum discharge power of the battery cluster and transmits them to the energy storage converter. The energy storage converter adjusts its output power in real time according to the real-time power value of the load, including: The energy storage converter adjusts its output power in real time based on the real-time power value of the load and the current remaining power and maximum discharge power of the battery cluster.

[0013] Optionally, the energy storage system further includes a photovoltaic maximum power tracker, which is connected to the photovoltaic panel, the DC bus, and the energy storage converter respectively; the control method further includes, before the energy storage converter adjusts its output power value in real time according to the real-time power value of the load: The photovoltaic maximum power tracker transmits the real-time power value of photovoltaic power generation to the energy storage converter; The energy storage converter adjusts its output power in real time according to the real-time power value of the load, including: The energy storage converter adjusts its output power in real time based on the real-time power value of the load, the current remaining power and maximum discharge power of the battery cluster, and the real-time power value of the photovoltaic power generation.

[0014] A third aspect of this application also provides an energy storage cabinet, which includes the energy storage system described in the first aspect.

[0015] Compared to existing technologies, this application provides an energy storage system, a control method for the energy storage system, and an energy storage cabinet. In this system, a static transfer switch directly collects the real-time power value of the load and transmits it to an energy storage converter. The energy storage converter directly adjusts its output power value in real time based on the real-time power value of the load transmitted by the static transfer switch. This direct and rapid data interaction between the static transfer switch and the energy storage converter effectively shortens the transmission path of the real-time power value of the load, reducing the response time of the energy storage system to load power fluctuations from hundreds of milliseconds to tens of milliseconds. This significantly improves the response speed of the energy storage converter to load power fluctuations, enabling the energy storage system to quickly track load power fluctuations and reduce the risk of reverse current. Furthermore, this energy storage system can more fully utilize new energy sources, reduce the consumption of grid power, and save on electricity costs. Attached Figure Description

[0016] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a schematic diagram of an existing photovoltaic energy storage cabinet; Figure 2 This is a schematic diagram of an energy storage system provided in this application; Figure 3 This is a flowchart illustrating a control method for an energy storage system provided in this application; Figure 4 This is a flowchart illustrating another control method for an energy storage system provided in this application; Figure 5 This is a flowchart illustrating another control method for an energy storage system provided in this application; Figure 6 This is a schematic diagram of an energy storage cabinet provided in this application. Detailed Implementation

[0018] To facilitate understanding of this application, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "bottom," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0020] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0021] The following explanations of some terms used in the embodiments of this application are provided to facilitate understanding by those skilled in the art.

[0022] An energy storage converter is a device that enables bidirectional flow of electrical energy. When the battery is charging, the energy storage converter converts the AC power from the grid side into DC power to charge the battery; when the battery is discharging, the energy storage converter converts the DC power from the battery side into AC power to supply AC loads.

[0023] The theoretical basis of the embodiments of this application will be explained below to facilitate understanding by those skilled in the art.

[0024] When the energy storage system of the energy storage cabinet is charging, it needs to absorb electrical energy from the grid, and there will be no backflow phenomenon. In the off-grid state, the energy storage system is physically isolated from the grid, and there will be no backflow phenomenon. Therefore, the backflow of the energy storage system will only occur during the grid-connected discharge process. This application only introduces how to prevent backflow when the energy storage system is grid-connected for discharge.

[0025] To illustrate the detailed process of this application, the following settings are made: the active power of the A, B, and C phases of the load detected by the static transfer switch are respectively... , , The reactive power is respectively , , The wattmeter on the grid side detected the active power of the A, B, and C phases input to the grid at the grid connection point as follows: , , The reactive power is respectively , , The active power output of the energy storage converter for phases A, B, and C are respectively , , The reactive power is respectively , , .

[0026] The active power of the three phases A, B, and C of AC between the energy storage converter, the load, and the power grid satisfies formula (1): (1) The relationship between the active power of the three phases A, B, and C can be expressed by the general formula as shown in formula (2): (2) The three-phase reactive power rates of AC A, B, and C between the energy storage converter, load, and power grid satisfy formula (3): (3) The relationship between the three-phase reactive power of A, B, and C can be expressed by the general formula as shown in formula (4): (4) From formulas (2) and (4), it can be seen that in steady state, to achieve a complete absence of backflow into the grid, the active and reactive power of the grid's three phases A, B, and C must satisfy formula (5): (5) At this point, it is required that the power output of the energy storage converter is perfectly matched with the power absorbed by the load, that is, the power output of the energy storage converter and the power absorbed by the load satisfy formula (6): (6) When the load power changes, the change in active power is: The change in reactive power is At this point, formulas (2) and (4) become formula (7): (7) If the energy storage converter responds slowly to load changes, it means that the output of the energy storage converter will be slow after the load changes. It remains the same as the value from the previous cycle, which is the same as the load value from the previous cycle. Since they are equal, formula (7) can be simplified to formula (8): (8)

[0027] When the load increases, the amount of change in load. A value greater than 0 means that the load needs to absorb more power from the grid, increasing the cost for users to purchase electricity from the grid.

[0028] The amount of change in load when the load decreases. A value less than 0 means that the load cannot fully absorb the electrical energy output by the energy storage converter, and the excess electrical energy will flow back to the grid. This is the situation that this application aims to suppress.

[0029] Theoretical analysis shows that the faster the response of the energy storage converter, the better the effect of suppressing reverse current. The existing method of preventing reverse current in energy storage systems is to detect the load power information by a wattmeter on the load side and transmit the detection result data to the energy management subsystem. After comprehensive processing, the energy management subsystem transmits the target power data to the energy storage converter, and finally the energy storage converter executes the target power. The entire response time is at least several hundred milliseconds.

[0030] This application utilizes a static transfer switch within the energy storage system to collect real-time active and reactive power components of the load and promptly transmits this information to the energy storage converter. The energy storage converter then performs rapid adjustments based on these active and reactive power components, with the entire response time controllable within tens of milliseconds, effectively suppressing reverse current. Understandably, the energy storage converter's adjustment of its own output power also needs to reference its rated maximum output power; the final output power value cannot exceed its rated maximum output power.

[0031] The energy storage system, control method, and energy storage cabinet provided in this application are described in detail below with reference to the accompanying drawings.

[0032] In one embodiment, this application provides an energy storage system, such as Figure 2 As shown, Figure 2 This is a schematic diagram of an energy storage system provided in this application. The energy storage system includes an energy storage converter and a static transfer switch; The energy storage converter is connected to the battery cluster via a DC bus. The static transfer switch is connected to the energy storage converter, the load, and the grid connection point, respectively. The grid connection point is connected to the power grid. The battery clusters are used for storing electrical energy; The static transfer switch is used to collect the real-time power value of the load and transmit it to the energy storage converter. The energy storage converter is used to adjust its own output power value in real time according to the real-time power value of the received load.

[0033] Specifically, the static transfer switch is connected to the energy storage converter, the load, and the grid connection point via an AC bus. The static transfer switch is also communicatively connected to the energy storage converter. This communication connection can be a controller area network (CLAN) or an RS485 serial differential communication connection, or other communication methods. This embodiment does not limit the specific communication connection method between the two. Figure 2 The following explanation uses a controller area network (CLAN) communication method as an example. During grid-connected discharge, the static transfer switch collects the real-time power values ​​of the load, including the real-time voltage and current values. Based on these values, it calculates the active and reactive power of each phase and transmits the results to the energy storage converter via a communication line. The energy storage converter adjusts its output power in real time based on the received real-time load power values, effectively shortening the power transmission path and significantly improving its response speed to load power fluctuations, thus reducing the risk of reverse current. Furthermore, the energy consumed by the load in this energy storage system primarily comes from renewable energy sources, reducing grid power consumption and saving electricity costs. These renewable energy sources can be generated from solar, wind, and other renewable energy sources. Furthermore, this energy storage system directly collects the real-time power value of the load through a static transfer switch, eliminating the need for a wattmeter on the load side and saving system hardware costs.

[0034] In one embodiment, the energy storage converter is also connected to a battery management subsystem, which collects the current remaining charge and maximum discharge power of the battery cluster and transmits them to the energy storage converter. The energy storage converter is used to adjust its output power in real time according to the received real-time power value of the load, including: The energy storage converter is used to adjust its output power value in real time according to the real-time power value of the load and the current remaining power and maximum discharge power of the battery cluster.

[0035] In this embodiment, the battery management subsystem is communicatively connected to the energy storage converter. The specific communication connection method can be a controller area network (Controller Area Network) or an RS485 serial differential communication connection, or other communication connection methods. This embodiment does not limit the specific communication connection method between the two. Figure 2The following explanation uses a controller area network (CLAN) communication method as an example. The battery management subsystem collects the current remaining charge and maximum discharge power of the battery clusters, including: collecting the temperature and voltage values ​​of the battery clusters; calculating the current remaining charge and maximum discharge power based on the temperature and voltage values; and transmitting the current remaining charge and maximum discharge power of the battery clusters to the energy storage converter. The energy storage converter adjusts its output power in real time according to the real-time power value of the load and the current remaining charge and maximum discharge power of the battery clusters, including: within the allowable range of the current remaining charge and maximum discharge power of the battery clusters, the energy storage converter adjusts its output power in real time according to the real-time power value of the load to reduce the risk of reverse current.

[0036] In one embodiment, the energy storage system further includes a photovoltaic maximum power tracker, which is connected to the photovoltaic panel and the DC bus respectively, for tracking the maximum power of photovoltaic power generation.

[0037] In this embodiment, the energy storage system is a photovoltaic energy storage system. It tracks the maximum power of photovoltaic power generation through a photovoltaic maximum power tracker, thereby making greater use of solar energy, reducing the consumption of grid power, and saving user costs.

[0038] In one embodiment, the photovoltaic maximum power tracker is also connected to the energy storage converter to transmit the real-time power value of the photovoltaic power generation to the energy storage converter. The energy storage converter is used to adjust its output power in real time according to the received real-time power value of the load, including: The energy storage converter is used to adjust its output power value in real time according to the real-time power value of the load, the current remaining power and maximum discharge power of the battery cluster, and the real-time power value of the photovoltaic power generation.

[0039] In this embodiment, the photovoltaic maximum power tracker and the energy storage converter are communicatively connected. The specific communication connection method can be Ethernet or RS485 serial differential communication, or other communication methods. This embodiment does not limit the specific communication connection method between the two. Figure 2 The following explanation uses RS485 serial differential communication as an example. The energy storage converter adjusts its output power in real time based on the real-time power value of the load, the current remaining charge and maximum discharge power of the battery cluster, and the real-time power value of the photovoltaic power generation. This includes: the energy storage converter prioritizes using the power output from the photovoltaic power generation to supply power to the load; when the power output from the photovoltaic power generation cannot meet the load's demand, it then supplements the load with the power from the battery cluster, within the allowable range of the current remaining charge and maximum discharge power of the battery cluster, to maximize the utilization of solar energy, reduce the consumption of grid power, and save user costs.

[0040] In one embodiment, the energy storage converter and the static transfer switch are connected via a controller area network or RS485 serial differential communication.

[0041] In this embodiment, the controller local area network communication between the energy storage converter and the static transfer switch has good real-time performance, which can ensure the real-time tracking of load power fluctuations by the energy storage converter, thereby reducing the risk of reverse current. The RS485 serial differential communication method has a simple structure, low hardware cost, good fault tolerance, and high reliability, which can also reduce the risk of reverse current.

[0042] In one embodiment, the static transfer switch is also used to collect the voltage value of the power grid and determine whether the energy storage system is connected to or disconnected from the grid based on the collected voltage value of the power grid.

[0043] In this embodiment, the static transfer switch collects the three-phase AC voltage from the grid side in real time, using voltage quality as the basis for determining whether the energy storage system is connected to or disconnected from the grid. Specifically, voltage quality includes: whether the voltage amplitude is within the preset normal range, whether there are overvoltage or undervoltage phenomena, whether there are phase loss or phase breakage faults in the three-phase voltage, and whether the grid frequency is within the preset normal operating range. For example, if the voltage amplitude is within the preset normal range, there are no overvoltage or undervoltage phenomena, the three-phase voltage has no phase loss or phase breakage faults, and the grid frequency is within the preset normal operating range, the static transfer switch determines that the grid power supply is normal, and the energy storage system operates in grid-connected mode; otherwise, the energy storage system operates in off-grid mode.

[0044] Optionally, such as Figure 2 As shown, the energy storage system also includes an energy management subsystem, which is connected to the energy storage converter, static transfer switch, photovoltaic maximum power tracker, battery management subsystem and grid-side wattmeter respectively. The grid-side wattmeter is used to monitor and measure the electrical parameters of the grid connection point, and transmits the electrical parameters of the grid connection point to the energy management subsystem. The energy storage converter, static transfer switch, photovoltaic maximum power tracker, and battery management subsystem are also used to transmit their own electrical parameters to the energy management subsystem. The energy management subsystem is used to collect and manage the electrical parameters of the energy storage converter, static transfer switch, photovoltaic maximum power tracker, battery management subsystem, and grid-side wattmeter.

[0045] Specifically, the connection method between the energy management subsystem and the energy storage converter, static transfer switch, photovoltaic maximum power tracker, battery management subsystem, and grid-side wattmeter. Figure 2This embodiment uses RS485 serial differential communication as an example for explanation. Other communication methods such as Ethernet can also be used, but this embodiment does not limit the specific communication connection method. The energy management subsystem collects and comprehensively manages and displays the electrical parameters of the energy storage converter, static transfer switch, photovoltaic maximum power tracker, battery management subsystem, and grid-side wattmeter. The specific electrical parameters collected by the energy management subsystem from each functional module and how they are managed and displayed can be set according to specific needs; this embodiment does not limit this.

[0046] In this energy storage system, the static transfer switch directly collects the real-time power value of the load and transmits it to the energy storage converter. The energy storage converter directly adjusts its own output power value in real time based on the real-time power value of the load transmitted by the static transfer switch, thereby effectively shortening the transmission path of the load power value and reducing the response time of the energy storage system to load power fluctuations from hundreds of milliseconds to tens of milliseconds. This significantly improves the response speed of the energy storage converter to load power fluctuations and reduces the risk of reverse current. Furthermore, this energy storage system can make fuller use of new energy sources, reduce the consumption of grid power, and save on electricity costs.

[0047] Based on the same concept, in another embodiment, this application provides a control method for an energy storage system, such as... Figure 3 As shown, Figure 3 This is a flowchart illustrating a control method for an energy storage system provided in this application. This control method is applied to energy storage systems, such as... Figure 2 As shown, the energy storage system includes an energy storage converter and a static transfer switch. The energy storage converter is connected to the battery cluster via a DC bus. The static transfer switch is connected to the energy storage converter, the load, and the grid connection point, respectively. The grid connection point is connected to the power grid. The control method includes: S10. The static transfer switch collects the real-time power value of the load and transmits it to the energy storage converter. S20. The energy storage converter adjusts its output power value in real time according to the real-time power value of the load.

[0048] Specifically, during grid-connected discharge of the energy storage system, the static transfer switch collects the real-time power value of the load and transmits it to the energy storage converter. The energy storage converter adjusts its output power value in real time based on the received real-time power value of the load, thereby effectively shortening the transmission path of the load power value, significantly improving the response speed of the energy storage converter to load power fluctuations, and reducing the risk of reverse current. Furthermore, the electrical energy consumed by the load of this energy storage system comes more from renewable energy sources, which can reduce the consumption of grid power and save electricity costs. These renewable energy sources can be electricity generated from solar, wind, and other renewable energy sources.

[0049] In one implementation, such as Figure 2 As shown, the energy storage converter is also connected to the battery management subsystem. Figure 4 As shown, Figure 4 This is a flowchart illustrating another control method for an energy storage system provided in this application. Before the energy storage converter adjusts its output power value in real time according to the real-time power value of the load, the control method further includes: S30. The battery management subsystem collects the current remaining power and maximum discharge power of the battery cluster and transmits them to the energy storage converter. The energy storage converter adjusts its output power in real time according to the real-time power value of the load, including: S21. The energy storage converter adjusts its output power value in real time according to the real-time power value of the load and the current remaining power and maximum discharge power of the battery cluster.

[0050] In this embodiment, the battery management subsystem collects the current remaining charge and maximum discharge power of the battery cluster and transmits them to the energy storage converter. Within the allowable range of the current remaining charge and maximum discharge power of the battery cluster, the energy storage converter adjusts its output power in real time according to the real-time power value of the load to reduce the risk of reverse current. It is understood that the steps of the battery management subsystem collecting the current remaining charge and maximum discharge power of the battery cluster and transmitting them to the energy storage converter, and the steps of the static transfer switch collecting the real-time power value of the load and transmitting it to the energy storage converter, can be performed simultaneously or in any order. This embodiment does not limit the execution order of these two steps.

[0051] In one implementation, such as Figure 2 As shown, the energy storage system also includes a photovoltaic maximum power tracker, which is connected to the photovoltaic panel, the DC bus, and the energy storage converter. Figure 5 As shown, Figure 5 This is a flowchart illustrating another control method for an energy storage system provided in this application. Before the energy storage converter adjusts its output power value in real time according to the real-time power value of the load, the control method further includes: S40. The photovoltaic maximum power tracker transmits the real-time power value of photovoltaic power generation to the energy storage converter. The energy storage converter adjusts its output power in real time according to the real-time power value of the load, including: S22. The energy storage converter adjusts its output power in real time according to the real-time power value of the load, the current remaining power and maximum discharge power of the battery cluster, and the real-time power value of the photovoltaic power generation.

[0052] In this embodiment, the energy storage converter prioritizes using the electrical energy output from photovoltaic power generation to power the load. When the power output from photovoltaic power generation cannot meet the load's demand, it supplements the load with the electrical energy from the battery clusters, within the allowable range of the current remaining charge and maximum discharge power of the battery clusters. This maximizes the utilization of solar energy, reduces the consumption of grid power, and saves user costs. It is understood that the steps of the battery management subsystem collecting the current remaining charge and maximum discharge power of the battery clusters and transmitting them to the energy storage converter, the steps of the static transfer switch collecting the real-time power value of the load and transmitting it to the energy storage converter, and the steps of the photovoltaic maximum power tracker transmitting the real-time power value of photovoltaic power generation to the energy storage converter can be performed simultaneously or in any order. This embodiment does not limit the execution order of these three steps.

[0053] In the control method of the energy storage system in this embodiment, the static transfer switch directly collects the real-time power value of the load and transmits it to the energy storage converter. The energy storage converter directly adjusts its own output power value in real time according to the real-time power value of the load transmitted by the static transfer switch, thereby effectively shortening the transmission path of the load power value and compressing the response time of the energy storage system to load power fluctuations from hundreds of milliseconds to tens of milliseconds. This significantly improves the response speed of the energy storage converter to load power fluctuations and reduces the risk of reverse current. Furthermore, this energy storage system can make fuller use of new energy sources, reduce the consumption of grid power, and save electricity costs.

[0054] Based on the same concept, in another embodiment, please refer to Figure 6 , Figure 6 This is a schematic diagram of an energy storage cabinet provided in this application, which includes the energy storage system described in the above embodiment.

[0055] In this embodiment, the energy storage cabinet directly collects the real-time power value of the load and transmits it to the energy storage converter. The energy storage converter directly adjusts its own output power value in real time according to the real-time power value of the load transmitted by the static transfer switch, thereby effectively shortening the transmission path of the load power value and reducing the response time of the energy storage system to load power fluctuations from hundreds of milliseconds to tens of milliseconds. This significantly improves the response speed of the energy storage converter to load power fluctuations and reduces the risk of reverse current. Furthermore, this energy storage system can make fuller use of new energy sources, reduce the consumption of grid power, and save on electricity costs.

[0056] It should be noted that the above-described energy storage system embodiments, energy storage system control methods, and energy storage cabinet embodiments belong to the same concept. For details of their implementation process, please refer to the energy storage system embodiments. Furthermore, the technical features in the energy storage system embodiments are also applicable to the above-described energy storage system control method embodiments and energy storage cabinet embodiments, and will not be repeated here.

[0057] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0058] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of this application as described above. For the sake of brevity, they are not provided in detail. 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 of the technical features. 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.

Claims

1. An energy storage system, characterized in that, The energy storage system includes an energy storage converter and a static transfer switch; The energy storage converter is connected to the battery cluster via a DC bus. The static transfer switch is connected to the energy storage converter, the load, and the grid connection point, respectively. The grid connection point is connected to the power grid. The static transfer switch is used to collect the real-time power value of the load and transmit it to the energy storage converter. The energy storage converter is used to adjust its own output power value in real time according to the real-time power value of the received load.

2. The energy storage system according to claim 1, characterized in that, The energy storage converter is also connected to the battery management subsystem, which is used to collect the current remaining power and maximum discharge power of the battery cluster and transmit them to the energy storage converter. The energy storage converter is used to adjust its output power in real time according to the received real-time power value of the load, including: The energy storage converter is used to adjust its own output power value in real time according to the real-time power value of the load and the current remaining power and maximum discharge power of the battery cluster.

3. The energy storage system according to claim 2, characterized in that, The energy storage system also includes a photovoltaic maximum power tracker, which is connected to the photovoltaic panel and the DC bus respectively, and is used to track the maximum power of photovoltaic power generation.

4. The energy storage system according to claim 3, characterized in that, The photovoltaic maximum power tracker is also connected to the energy storage converter to transmit the real-time power value of photovoltaic power generation to the energy storage converter. The energy storage converter is used to adjust its output power in real time according to the received real-time power value of the load, including: The energy storage converter is used to adjust its output power value in real time according to the real-time power value of the load, the current remaining power and maximum discharge power of the battery cluster, and the real-time power value of the photovoltaic power generation.

5. The energy storage system according to claim 1, characterized in that, The energy storage converter and the static transfer switch are connected via a controller area network or RS485 serial differential communication.

6. The energy storage system according to any one of claims 1-5, characterized in that, The static transfer switch is also used to collect the voltage value of the power grid and determine whether the energy storage system is connected to or disconnected from the grid based on the collected voltage value of the power grid.

7. A control method for an energy storage system, characterized in that, The system is applied to an energy storage system, which includes an energy storage converter and a static transfer switch. The energy storage converter is connected to a battery cluster via a DC bus. The static transfer switch is connected to the energy storage converter, a load, and a grid connection point, respectively. The grid connection point is connected to the power grid. The control method includes: The static transfer switch collects the real-time power value of the load and transmits it to the energy storage converter; The energy storage converter adjusts its output power in real time according to the real-time power value of the load.

8. The control method according to claim 7, characterized in that, The energy storage converter is also connected to a battery management subsystem; the control method further includes, before the energy storage converter adjusts its output power value in real time according to the real-time power value of the load: The battery management subsystem collects the current remaining power and maximum discharge power of the battery cluster and transmits them to the energy storage converter. The energy storage converter adjusts its output power in real time according to the real-time power value of the load, including: The energy storage converter adjusts its output power in real time based on the real-time power value of the load and the current remaining power and maximum discharge power of the battery cluster.

9. The control method according to claim 8, characterized in that, The energy storage system further includes a photovoltaic maximum power tracker, which is connected to the photovoltaic panel, the DC bus, and the energy storage converter. The control method further includes, before the energy storage converter adjusts its output power value in real time according to the real-time power value of the load: The photovoltaic maximum power tracker transmits the real-time power value of photovoltaic power generation to the energy storage converter; The energy storage converter adjusts its output power in real time according to the real-time power value of the load, including: The energy storage converter adjusts its output power in real time based on the real-time power value of the load, the current remaining power and maximum discharge power of the battery cluster, and the real-time power value of the photovoltaic power generation.

10. An energy storage cabinet, characterized in that, The energy storage cabinet includes the energy storage system as described in any one of claims 1-6.

Images