Photovoltaic energy storage system and energy management method thereof

Abstract

The invention relates to a photovoltaic energy storage system and an energy management method thereof. The system comprises at least one photovoltaic energy storage unit, at least one pure energy storage unit, an energy management system and a high-voltage power distribution cabinet, a DCDC converter is introduced into the photovoltaic energy storage unit so as to carry out DC-DC conversion on photovoltaic power generation; the photovoltaic energy storage unit is electrically connected with the high-voltage power distribution cabinet so as to realize bidirectional flow of electric energy; the pure energy storage unit is electrically connected with the high-voltage power distribution cabinet so as to realize bidirectional flow of electric energy; the high-voltage power distribution cabinet accesses a power grid; and based on a preset charging and discharging mode, the energy management system performs charging and discharging management on the photovoltaic energy storage unit and the pure energy storage unit according to the residual electric quantity of the photovoltaic energy storage unit, the residual electric quantity of the pure energy storage unit and the output power of the DCDC converter so as to realize residual energy deviation balance control. According to the application, the problem of system energy incoordination can be solved while the continuous stability of the system capacity can be realized.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic energy storage technology, and in particular to a photovoltaic energy storage system and an energy management method thereof. Background Art

[0002] In a related technology, most photovoltaic energy storage power stations use Figure 1 The system architecture shown is shown. On the photovoltaic side, photovoltaic panels are connected to a photovoltaic inverter, which is then converted to high voltage via a transformer. On the energy storage side, a lithium battery storage container is connected to a storage inverter (PCS), which is then converted to high voltage via a booster tank. Both the photovoltaic and energy storage sides are connected to a high-voltage distribution cabinet, which is then connected to the grid. This enables the photovoltaic power station to access the grid, while the energy storage container stores electricity. In this architecture, multiple such links are connected in parallel on the photovoltaic side, and multiple energy storage links are also connected in parallel on the energy storage side. This is the mainstream topology for large-scale photovoltaic and energy storage systems. However, in this solution, the energy from photovoltaics entering the energy storage system must undergo multiple conversions, including a photovoltaic inverter, two transformers, and a storage inverter. This results in very low efficiency and is suitable for applications with limited storage capacity.

[0003] In another related technology, the photovoltaic energy storage system architecture is as follows Figure 2 As shown, by introducing a DC to DC converter (DCDC), the electricity from the photovoltaic power station is directly converted into energy suitable for lithium battery energy storage containers, which can reduce Figure 1 The electric energy in the medium system architecture enters the energy storage unit circulation link, improving the overall efficiency. Figure 2 The medium-sized topology is widely used in micro-grids, but is rarely used in large-scale photovoltaic power plants. In order to cope with the low or negative electricity prices during photovoltaic power generation, the energy storage capacity configured in photovoltaic power plants is getting larger and larger. When the energy storage capacity is close to the photovoltaic power generation, the energy storage capacity is used. Figure 2 The topology of this architecture will achieve better photovoltaic power storage efficiency. Lithium batteries experience lifespan degradation over time, and the capacity of the entire energy storage station will gradually decrease during actual use. If users require 100% capacity during use, additional lithium battery storage containers will be needed to compensate for the lifetime degradation of the existing containers. Adding energy storage containers without adding photovoltaic panels will lead to energy inconsistency issues between the additional containers and the energy storage containers connected to the photovoltaic panels. Summary of the Invention

[0004] Based on the above description, the present application provides a photovoltaic energy storage system and an energy management method thereof, which can achieve continuous stability of system capacity while achieving consistency in energy coordination of the energy storage system.

[0005] In a first aspect, the present application provides a photovoltaic energy storage system, comprising: at least one photovoltaic energy storage unit, at least one pure energy storage unit, an energy management system, and a high-voltage distribution cabinet; a DC-DC converter is introduced into the photovoltaic energy storage unit to convert photovoltaic power generation into DC-DC; The photovoltaic energy storage unit is electrically connected to the high-voltage distribution cabinet to achieve a two-way flow of electric energy; the pure energy storage unit is electrically connected to the high-voltage distribution cabinet to achieve a two-way flow of electric energy; the high-voltage distribution cabinet is connected to the power grid; The remaining energy of the photovoltaic energy storage unit, the remaining energy of the pure energy storage unit, and the average remaining power of the power station are obtained in real time to determine the actual power station remaining energy deviation. The average coordinated power station power is determined based on the actual power station remaining energy deviation and a preset total reference deviation of the power station remaining energy. The energy management system obtains the charging and discharging mode from the dispatching center, and based on the output power of all the DCDC converters, the average coordinated power station power, and the preset reference charging and discharging power, manages the charging and discharging of the photovoltaic energy storage unit and the pure energy storage unit, determines the charging and discharging power requirements of the photovoltaic energy storage unit and the pure energy storage unit, and realizes the balance control of the remaining energy deviation.

[0006] In one or more embodiments, the photovoltaic energy storage unit includes a photovoltaic battery group, a DCDC converter, a first energy storage module, a first converter, a first transformer, and a first coordination controller; The photovoltaic battery group is used to generate photovoltaic power and output electrical energy. After conversion by the DCDC converter, the electrical energy is output to the corresponding first energy storage module and the corresponding first converter, so that the first converter performs power conversion on the electrical energy and outputs it to the first transformer. The first transformer then boosts the electrical energy and transmits it to the high-voltage distribution cabinet. The first energy storage module is used to store or discharge energy. The first coordination controller is connected to the energy management system, and is used to control the DCDC converter, the first energy storage module and the first converter based on a residual energy deviation balance control strategy.

[0007] In one or more embodiments, the pure energy storage unit includes a second energy storage module, a second converter, a second transformer, and a second coordination controller, wherein the second energy storage module is connected to the second converter; one side of the second converter is connected to the second transformer and the second coordination controller in sequence; and the second coordination controller is connected to the high-voltage distribution cabinet; The second energy storage module is used for storing or discharging energy; the second coordination controller is used for controlling the second energy storage module and the second converter based on a residual energy deviation balance control strategy.

[0008] In one or more embodiments, if the charge and discharge mode is the discharge-allowed mode, the discharge demand power of the current photovoltaic energy storage unit is determined based on the output power of all the DCDC converters, the average coordinated power, and the preset reference discharge power, and based on the difference between the current remaining energy of the photovoltaic energy storage unit and the average remaining power of the power station; Determining the discharge power requirement of the current pure energy storage unit based on the output power of all the DCDC converters, the average coordinated power, and the preset reference discharge power, and based on the difference between the current remaining energy of the pure energy storage unit and the average remaining power of the power station; If the charging and discharging mode is the charging-allowing mode, the current charging demand power of the photovoltaic energy storage unit is determined based on the output power of all the DCDC converters, the average coordinated power, and the preset reference charging power, and based on the difference between the average remaining power of the power station and the current remaining energy of the photovoltaic energy storage unit; The charging demand power of the current pure energy storage unit is determined based on the output power of all the DCDC converters, the average coordinated power and the preset reference charging power, and based on the difference between the average remaining power of the power station and the remaining energy of the current pure energy storage unit.

[0009] In one or more embodiments, the actual power station residual energy deviation can be determined according to the following calculation formula: : ; in, represents the remaining energy of the A-th photovoltaic energy storage unit; represents the remaining energy of the Bth pure energy storage unit; Indicates the average remaining energy of the power station; A=1...N, N is the total number of photovoltaic energy storage units; B=1...M, M is the total number of pure energy storage units; Determine the average coordinated power of the power station according to the following calculation formula :

[0010] in, =(M+N)× ; Indicates the total reference deviation of the remaining energy of the power station; Indicates the allowable deviation of the remaining energy of the power station; Represents the average coordinated power coefficient of the energy management system.

[0011] In one or more embodiments, if the charge and discharge mode obtained from the dispatch center is the discharge-allowed mode, the discharge power requirement of the current photovoltaic energy storage unit is calculated according to the following formula: and the discharge power requirement of the current pure energy storage unit : ; ; in, is the preset reference discharge power; Indicates the total output power of all DCDC converters in the current photovoltaic energy storage unit; Represents the average coordinated power of the power station; A=1...N, N is the total number of photovoltaic energy storage units; B=1...M, M is the total number of pure energy storage units; represents the remaining energy of the A-th photovoltaic energy storage unit; represents the remaining energy of the Bth pure energy storage unit; Indicates the average remaining energy of the power station.

[0012] In one or more embodiments, if the charging and discharging mode obtained from the dispatch center is the charging mode, the current charging demand power of the photovoltaic energy storage unit is calculated according to the following formula: and the charging power requirement of the current pure energy storage unit : ; ; in, is the preset reference charging power; Indicates the total output power of all DCDC converters in the current photovoltaic energy storage unit; Represents the average coordinated power of the power station; A=1...N, N is the total number of photovoltaic energy storage units; B=1...M, M is the total number of pure energy storage units; represents the remaining energy of the A-th photovoltaic energy storage unit; represents the remaining energy of the Bth pure energy storage unit; Indicates the average remaining energy of the power station.

[0013] In one or more embodiments, further comprising: Acquire the remaining energy and average remaining energy of the first energy storage module in the photovoltaic energy storage unit in real time, and determine the actual remaining energy deviation of the photovoltaic energy storage unit; Determining the average coordinated power of the photovoltaic energy storage unit according to the actual remaining energy deviation in the photovoltaic energy storage unit and the first preset average remaining energy reference deviation; The current photovoltaic energy storage unit obtains the charging and discharging mode from the energy management system, and determines the charging and discharging required power of the first converter in the current photovoltaic energy storage unit based on the output power of the DCDC converter in the current photovoltaic energy storage unit, the average coordinated power of the current photovoltaic energy storage unit, and the charging and discharging required power.

[0014] In one or more embodiments, the actual remaining energy deviation of the photovoltaic energy storage unit is determined according to the following calculation formula: :

[0015] in, Represents the remaining energy of the MAth first energy storage module in the current photovoltaic energy storage unit; Represents the average remaining energy of all first energy storage modules in the current photovoltaic energy storage unit; MA=1...L, where L is the total number of first energy storage modules in the current photovoltaic energy storage unit; The average coordinated power of the current photovoltaic energy storage unit is determined according to the following calculation formula :

[0016] in, ; Indicates a first preset average remaining energy reference deviation of the current photovoltaic energy storage unit; Indicates the allowable deviation of the average remaining energy in the current photovoltaic energy storage unit; Indicates the current residual energy deviation proportional coefficient of the photovoltaic energy storage unit.

[0017] In one or more embodiments, if the charge and discharge mode obtained from the energy management system is the discharge-allowed mode, the discharge power requirement of the MAth first converter in the current photovoltaic energy storage unit is calculated according to the following formula: ; ; If the charging and discharging mode obtained from the energy management system is the charging mode, the charging demand power of the MAth first converter in the current photovoltaic energy storage unit is calculated according to the following formula: ; ; in, Indicates the current discharge power requirement of the photovoltaic energy storage unit; Indicates the current charging power requirement of the photovoltaic energy storage unit; Represents the output power of the MAth DCDC converter in the current photovoltaic energy storage unit; Indicates the average coordinated power of the current photovoltaic energy storage unit; Represents the remaining energy of the MAth first energy storage module in the current photovoltaic energy storage unit; Represents the average remaining energy of all first energy storage modules in the current photovoltaic energy storage unit; MA=1...L, where L is the total number of first energy storage modules in the current photovoltaic energy storage unit.

[0018] In one or more embodiments, further comprising: Acquire the remaining energy and average remaining energy of the second energy storage module in the current pure energy storage unit in real time, and determine the actual remaining energy deviation of the current pure energy storage unit; Determining the average coordinated power of the current pure energy storage unit according to the actual remaining energy deviation in the current pure energy storage unit and the second preset average remaining energy reference deviation; The current pure energy storage unit obtains the charge and discharge mode from the energy management system, and determines the charge and discharge required power of the second converter in the current pure energy storage unit according to the average coordinated power and the charge and discharge required power in the current pure energy storage unit.

[0019] In one or more embodiments, the actual remaining energy deviation of the current pure energy storage unit is determined according to the following calculation formula: :

[0020] in, Represents the remaining energy of the MBth second energy storage module in the current pure energy storage unit; represents the average remaining energy of all second energy storage modules in the current pure energy storage unit; MB=1...K, where K is the total number of second energy storage modules in the current pure energy storage unit; The average coordinated power of the current pure energy storage unit is determined according to the following calculation formula :

[0021] in, ; Indicates a second preset average remaining energy reference deviation of the current pure energy storage unit; Indicates the allowable deviation of the average remaining energy in the current pure energy storage unit; Indicates the current residual energy deviation proportional coefficient of the pure energy storage unit.

[0022] In one or more embodiments, if the charge and discharge mode obtained from the energy management system is the discharge-allowed mode, the discharge power requirement of the MBth second converter in the current pure energy storage unit is calculated according to the following formula: ; ; If the charging and discharging mode obtained from the energy management system is the charging mode, the charging power requirement of the MBth second converter in the current pure energy storage unit is calculated according to the following formula: ; ; in, Indicates the current discharge power requirement of the pure energy storage unit; Indicates the current charging power requirement of the pure energy storage unit; Indicates the average coordinated power of the current pure energy storage unit; Represents the remaining energy of the MBth second energy storage module in the current pure energy storage unit; Represents the average remaining energy of all second energy storage modules in the current pure energy storage unit; MB=1... , is the total number of second energy storage modules in the current pure energy storage unit.

[0023] Compared with the prior art, the technical solution of this application has the following beneficial technical effects: In the above-mentioned photovoltaic energy storage system and its energy management method, the introduction of a DCDC converter in the photovoltaic energy storage unit can directly convert the electricity generated by the photovoltaic power station into energy suitable for storage in the energy storage container, reducing the number of power circulation loops and improving overall efficiency. On the basis of the photovoltaic energy storage architecture, a pure energy storage unit is added to realize a photovoltaic energy storage system with increased energy storage capacity. This allows the addition of energy storage containers during use to compensate for the attenuation of the original container capacity and ensure the continuous stability of the system capacity. At the same time, the energy management system manages the charging and discharging of the photovoltaic energy storage unit and the pure energy storage unit based on the remaining power of the photovoltaic energy storage unit, the remaining power of the pure energy storage unit, and the output power of the DCDC converter to achieve residual energy deviation balance control and strive to achieve residual energy consistency in each energy storage unit, which is conducive to extending the life of the energy storage battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the topology of a photovoltaic energy storage system in a related art; Figure 2 A schematic diagram of the topology of a photovoltaic energy storage system in another related technology; Figure 3 This is a schematic diagram of the principle of a photovoltaic energy storage system in one embodiment of the present application; Figure 4 for Figure 3 Schematic diagram of the architecture topology of the photovoltaic energy storage system; Figure 5 This is a flow chart of an energy management method for a photovoltaic energy storage system according to an embodiment of the present application; Figure 6 This is a flow chart of an energy management method for a photovoltaic energy storage system according to another embodiment of the present application; Figure 7 Schematic diagram of a flow chart of an energy management method for a photovoltaic energy storage system in another embodiment of the present application. DETAILED DESCRIPTION

[0025] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0027] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediate element. In the following embodiments, "connection" should be understood as "electrical connection", "communication connection", etc. if the connected circuits, units, and elements have electrical signals or data transmission between each other.

[0028] When used herein, the singular forms "a", "an", and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0029] In related art, Figure 1 The large-scale photovoltaic power station shown in the figure faces the problem of low photovoltaic power storage efficiency when a higher proportion of storage is allocated. Figure 2 The large-scale photovoltaic power station shown can improve efficiency, but when it is necessary to increase integration or reduce costs, a high proportion of storage power stations may lead to Figure 2Some energy storage containers lack DC-DC connections and PV panels. Alternatively, users may require 100% capacity during their lifetime and add additional storage containers in the early years to compensate for battery degradation. This results in the added containers lacking DC-DC connections and PV panels. These factors have led to the division of power plants into pure energy storage areas and energy storage areas with PV. This shift poses significant challenges to power plant energy management. Traditional power allocation focuses primarily on matching PV and energy storage, maximizing solar energy utilization, but fails to address the energy coordination issues between pure energy storage and PV storage.

[0030] Based on this, the embodiments of the present application provide a photovoltaic energy storage system and an energy management method, which can achieve continuous stability of system capacity while achieving consistency in energy coordination of the energy storage system.

[0031] See Figure 3 and Figure 4 , Figure 3 A schematic diagram showing the principle of a photovoltaic energy storage system in one embodiment of the present application is shown; Figure 4 Shown Figure 3 Schematic diagram of the architectural topology of the photovoltaic energy storage system.

[0032] A photovoltaic energy storage system provided by one embodiment of the present application includes: at least one photovoltaic energy storage unit, at least one pure energy storage unit, an energy management system, and a high-voltage distribution cabinet; a DCDC converter is introduced into the photovoltaic energy storage unit to convert photovoltaic power generation from DC to DC. The photovoltaic energy storage unit and the high-voltage distribution cabinet are electrically connected to achieve a two-way flow of electric energy; the pure energy storage unit and the high-voltage distribution cabinet are electrically connected to achieve a two-way flow of electric energy; and the high-voltage distribution cabinet is connected to the power grid. Based on a preset charge and discharge mode, the energy management system manages the charge and discharge of the photovoltaic energy storage unit and the pure energy storage unit according to the remaining power of the photovoltaic energy storage unit, the remaining power of the pure energy storage unit, and the output power of the DCDC converter to achieve balance control of the remaining energy deviation.

[0033] It should be noted that the photovoltaic energy storage system is a hybrid energy storage power station with a photovoltaic energy storage area and a pure energy storage area. The photovoltaic energy storage area includes at least one photovoltaic energy storage unit, and the pure energy storage area includes at least one pure energy storage unit. A photovoltaic energy storage unit refers to a unit that can store energy and supply power to the grid through photovoltaic power generation. A pure energy storage unit refers to a unit that can store energy and supply power to the grid. The photovoltaic energy storage area is connected to the high-voltage distribution cabinet via power cables, enabling bidirectional power flow between the photovoltaic energy storage area and the high-voltage distribution cabinet. The pure energy storage area is connected to the high-voltage distribution cabinet via power cables, enabling bidirectional power flow between the pure energy storage area and the high-voltage distribution cabinet. The high-voltage distribution cabinet is connected to the power grid via power cables, enabling power flow between the photovoltaic energy storage area, the pure energy storage area, and the grid. The energy management system is connected to the photovoltaic energy storage area, the pure energy storage area, and the high-voltage distribution cabinet via signal lines, enabling signal communication between them. The power cables transmit power between these modules. In this embodiment, both the photovoltaic energy storage unit and the pure energy storage unit are provided in plurality. In other embodiments, both the photovoltaic energy storage unit and the pure energy storage unit can also be provided in one.

[0034] Specifically, the high-voltage port of each photovoltaic energy storage unit is connected to the high-voltage distribution cabinet via a power cable, and the high-voltage distribution cabinet is connected to the power grid. The high-voltage port of each pure energy storage unit is connected to the high-voltage distribution cabinet via a power cable. The photovoltaic energy storage unit is used to generate electricity and can store part of the electrical energy after DCDC conversion, while realizing the flow of electricity with the high-voltage distribution cabinet; the high-voltage distribution cabinet can transmit part of the electrical energy output by the photovoltaic energy storage unit to the power grid, and transmit the other part of the electrical energy to the pure energy storage unit for storage; the pure energy storage unit is used for energy storage or to supply power to the grid through the high-voltage distribution cabinet. In other words, the electricity generated by each photovoltaic energy storage unit can be supplied to the grid, or it can be stored by each photovoltaic energy storage unit and each pure energy storage unit. When power is needed to the grid, each photovoltaic energy storage unit and each pure energy storage unit can discharge.

[0035] In this embodiment, the introduction of a DCDC converter in the photovoltaic energy storage unit can directly convert the electricity generated by the photovoltaic power station into energy suitable for storage in the energy storage container, reduce the power flow loop, and improve overall efficiency. On the basis of the photovoltaic energy storage architecture, a pure energy storage unit is added to realize a photovoltaic energy storage system with increased energy storage capacity. In this way, it is allowed to add energy storage containers during use to compensate for the attenuation of the original container capacity and ensure the continuous stability of the system capacity. At the same time, based on the charging mode / discharging mode of the dispatching center, the energy management system performs charging / discharging management on each photovoltaic energy storage unit and each pure energy storage unit according to the remaining power of each photovoltaic energy storage unit, the remaining power of each pure energy storage unit, and the output power of each DCDC converter, so as to realize the balance control of the remaining energy deviation and try to achieve the consistency of the remaining energy of each energy storage unit, which is conducive to extending the life of the energy storage battery.

[0036] Continue reading Figure 4 In some embodiments, the photovoltaic energy storage unit includes a photovoltaic battery group, a DC-DC converter, a first energy storage module, a first converter, a first transformer, and a first coordination controller. The photovoltaic battery group is used to generate photovoltaic power and output electrical energy. After conversion by the DC-DC converter, the energy is output to the corresponding first energy storage module and the corresponding first converter, respectively. The first converter converts the electrical energy into power and outputs it to the first transformer, which then boosts the electrical energy and transmits it to the high-voltage distribution cabinet. The first energy storage module is used for energy storage or discharge. The first coordination controller is connected to the energy management system and is used to control the DC-DC converter, the first energy storage module, and the first converter based on the residual energy deviation balance control strategy.

[0037] It should be noted that the photovoltaic battery group is composed of one or more photovoltaic modules connected in series. In this embodiment, the photovoltaic battery group, DCDC converter, first energy storage module, and first converter of the photovoltaic energy storage unit are all set to multiple and one-to-one corresponding, and the first transformer and first coordination controller of the same photovoltaic energy storage unit are both set to one. In other embodiments, the photovoltaic battery group, DCDC converter, first energy storage module, and first converter of the photovoltaic energy storage unit can all be set to one, and the first transformer and first coordination controller of the same photovoltaic energy storage unit can all be set to one; or, the photovoltaic battery group, DCDC converter, first energy storage module, and first converter of the photovoltaic energy storage unit can all be set to multiple, and the first transformer and first coordination controller of the same photovoltaic energy storage unit can all be set to two or three, etc. Each combination of the first transformer and the first coordination corresponds to a combination of one or more photovoltaic battery groups, DCDC converters, first energy storage modules, and first converters. The specific settings can be determined according to actual conditions.

[0038] In the same photovoltaic energy storage unit, each photovoltaic battery group is connected to a corresponding DCDC converter via a power cable, each DCDC converter is connected to a corresponding first energy storage module via a power cable, each first energy storage module is connected to a corresponding first converter via a power cable, each first converter is connected to the first transformer via a power cable, and the first transformer is connected to the high-voltage distribution cabinet via a power cable. The power cables enable power transmission between the above modules.

[0039] In the same photovoltaic energy storage unit, the first coordination controller is connected to each DCDC converter via a signal line, and the first coordination controller is connected to the energy management system via a signal line. The DCDC converter transmits the current output power and maximum photovoltaic power generation power signal to the first coordination controller, and the first coordination controller transmits the maximum operating DCDC power to the current DCDC converter. The first coordination controller is connected to each first converter via a signal circuit. The first converter transmits the current charging power signal / discharging power signal to the energy management system via the first coordination controller. In this embodiment, the energy management system can determine whether the current first converter is operating normally based on the deviation between the charging power / discharging power requirement set for the current first converter and the currently received charging power / discharging power.

[0040] The first coordinating controller also transmits the current PV energy storage unit's permitted charging / discharging power and the remaining energy signal to the energy management system. The energy management system then transmits the charging / discharging mode and the required charging / discharging power signal for the current PV energy storage unit to the first coordinating controller. In this embodiment, the energy management system ensures that the required charging / discharging power signal does not exceed the permitted charging / discharging power of the PV energy storage unit based on the current permitted charging / discharging power of the PV energy storage unit.

[0041] The first coordination controller is connected to each first energy storage module via a signal line. In this embodiment, the first energy storage module can be a lithium battery energy storage container or a single cluster of lithium battery energy storage containers. The first energy storage module can transmit the current allowed charging power / allowed discharging power and remaining energy signal of the first energy storage module to the first coordination controller. In this embodiment, before the first converter controls the corresponding first energy storage module to charge or discharge, the first coordination controller may judge the charging requirement power / discharging requirement power set for the first converter based on the current allowable charging power / allowable discharging power of the first energy storage module. If the charging requirement power / discharging requirement power does not exceed the allowable charging power / allowable discharging power of the corresponding first energy storage module, the charging requirement power / discharging requirement power is sent to the first converter, and the first converter controls the charging or discharging of the corresponding first energy storage module. If the charging requirement power / discharging requirement power set for the first converter exceeds the allowable charging power / allowable discharging power of the corresponding first energy storage module, the charging requirement power / discharging requirement power set for the first converter is updated based on the allowable charging power / allowable discharging power of the corresponding first energy storage module, and the updated charging requirement power / discharging requirement power is sent to the first converter.

[0042] Specifically, the photovoltaic battery pack outputs electrical energy through photovoltaic power generation, which, after conversion by a DC-DC converter, is then output to the corresponding first energy storage module and the corresponding first converter. The first converter then performs power conversion on the energy and outputs it to the first transformer. The first transformer then steps up the voltage and transmits the energy to a high-voltage distribution cabinet, where it is then connected to the grid or transmitted to a pure energy storage unit. The first energy storage module is used for energy storage or discharge. The first coordination controller dynamically controls the corresponding first converter using a residual energy deviation balance control strategy based on the charging / discharging mode and charging / discharging power requirements signals issued by the energy management system for the current photovoltaic energy storage unit, and based on the residual energy of each first energy storage module and the output power of the corresponding DC-DC converter, to control the charging / discharging power of the first converter. This approach, by rationally controlling the charging / discharging power of each first converter, prevents the risk of overcharging and discharging of a single first energy storage module, thereby improving consistency across energy storage systems.

[0043] Continue reading Figure 4 In some embodiments, the pure energy storage unit includes a second energy storage module, a second converter, a second transformer, and a second coordinated controller. The second energy storage module is connected to the second converter; one side of the second converter is sequentially connected to the second transformer and the second coordinated controller; and the second coordinated controller is connected to a high-voltage distribution cabinet. The second energy storage module is used to store or discharge energy; the second coordinated controller is used to control the second energy storage module and the second converter based on a residual energy deviation balance control strategy.

[0044] It should be noted that in this embodiment, the second energy storage module and the second converter of the pure energy storage unit are both provided in multiple configurations, and the second transformer and the second coordinated controller of the same pure energy storage unit are both provided in one configuration. In other embodiments, the second energy storage module and the second converter of the pure energy storage unit may both be provided in one configuration, and the second transformer and the second coordinated controller of the same pure energy storage unit may both be provided in one configuration; alternatively, the second energy storage module and the second converter of the pure energy storage unit may both be provided in multiple configurations, and the second transformer and the second coordinated controller of the same pure energy storage unit may both be provided in two or three configurations, etc. The specific configuration may be determined based on actual conditions.

[0045] In this embodiment, the second energy storage module is connected to the second converter via a power cable; the second converter is connected to the second transformer via a power cable; the second transformer is connected to the high-voltage distribution cabinet via a power cable; and the power cable enables power transmission between the above modules. The second coordination controller is connected to the second converter via a signal circuit; the second coordination controller is connected to the energy management system via a signal line. The second converter can transmit the current charging power / discharging power signal to the energy management system via the second coordination controller. In this embodiment, the energy management system can determine whether the current second converter is operating normally based on the deviation between the charging demand power / discharging demand power set for the current second converter and the currently received charging power / discharging power.

[0046] The second coordination controller also transmits the allowed charging power / allowed discharging power of the current pure energy storage unit and the remaining energy signal of the pure energy storage unit to the energy management system, and the energy management system transmits the charging and discharging mode and the charging demand power / discharging demand power signal for the current pure energy storage unit to the second coordination controller. In this embodiment, the energy management system can ensure that the set charging demand power / discharging demand power signal does not exceed the allowed charging power / allowed discharging power of the current pure energy storage unit based on the allowed charging power / allowed discharging power of the current pure energy storage unit. In this embodiment, the second coordination controller and the second energy storage module are connected via a signal line. The second energy storage module can be a lithium battery energy storage container or a single cluster of lithium battery energy storage containers; the second energy storage module transmits the allowed charging and discharging power and remaining energy signals to the second coordination controller. In this embodiment, before the second converter controls the corresponding second energy storage module to charge or discharge, the second coordination controller may judge the charging requirement power / discharging requirement power set for the second converter based on the current allowable charging power / allowable discharging power of the second energy storage module. If the charging requirement power / discharging requirement power does not exceed the allowable charging power / allowable discharging power of the corresponding second energy storage module, the charging requirement power / discharging requirement power is sent to the second converter, and the second converter controls the charging or discharging of the corresponding second energy storage module. If the charging requirement power / discharging requirement power set for the second converter exceeds the allowable charging power / allowable discharging power of the corresponding second energy storage module, the charging requirement power / discharging requirement power set for the second converter is updated based on the allowable charging power / allowable discharging power of the corresponding second energy storage module, and the updated charging requirement power / discharging requirement power is sent to the second converter.

[0047] Specifically, the second energy storage module is used for energy storage or discharge, that is, charging or discharging. In the charging mode of the second energy storage module, the second transformer receives part of the electric energy transmitted by the high-voltage distribution cabinet and transmits the electric energy to the corresponding second energy storage module after conversion by each second converter to achieve the purpose of energy storage. In the discharge mode of the second energy storage module, the second energy storage module outputs electric energy to and outputs the electric energy to the high-voltage distribution cabinet after conversion by the second converter and the second transformer, so as to achieve power supply and grid access. The corresponding second converter is dynamically controlled by the second coordination controller based on the residual energy and residual energy deviation balance control strategy of each second energy storage unit to control the charging power / discharging power of the second converter. In this way, by reasonably controlling the charging power / discharging power of each second converter, the risk of excessive charging and discharging of a single second energy storage module is prevented, which helps to improve the consistency between energy storage systems.

[0048] The photovoltaic energy storage system in this embodiment adopts a partitioned architecture, with the photovoltaic energy storage area and pure energy storage area separately connected to high-voltage distribution cabinets. This system utilizes an energy management system to coordinate energy and information scheduling. Furthermore, by coordinating signal transmission between the controller and the energy management system, the power and mode of photovoltaic power generation and energy storage charging and discharging are precisely controlled, achieving more efficient and flexible system energy management.

[0049] Based on the same inventive concept, an embodiment of the present application also provides an energy management method for a photovoltaic energy storage system. The energy management method adopts a hierarchical control method, which is divided into a residual energy deviation balance control strategy of the photovoltaic energy storage area and the pure energy storage area based on the energy management system level, and a residual energy deviation balance control strategy of the photovoltaic energy storage area and the internal unit modules of the pure energy storage area based on the coordination controller level.

[0050] See Figure 5 , Figure 5 A flow chart of an energy management method for a photovoltaic energy storage system provided in an embodiment of the present application is shown.

[0051] An energy management method for a photovoltaic energy storage system provided in an embodiment of the present application includes the following steps: S501: Obtain the remaining energy of the photovoltaic energy storage unit, the remaining energy of the pure energy storage unit, and the average remaining power of the power station in real time to determine the actual remaining energy deviation of the power station.

[0052] In some embodiments, the actual power station residual energy deviation can be determined according to the following calculation formula: : ; in, represents the remaining energy of the A-th photovoltaic energy storage unit; represents the remaining energy of the Bth pure energy storage unit; Indicates the average remaining energy of the power station; A=1...N, N is the total number of photovoltaic energy storage units; B=1...M, M is the total number of pure energy storage units. In this embodiment, the average remaining energy of the power station is .

[0053] Specifically, the remaining energy SOE of the current photovoltaic energy storage unit is obtained from the first coordination controller of the photovoltaic energy storage unit in the photovoltaic energy storage area by communication. A , that is, the remaining energy SOE of the A-th photovoltaic energy storage unit A , and obtain the total output power POWER of all DCDC converters in the current photovoltaic energy storage unit DCDC_A In addition, the remaining energy SOE of the current pure energy storage unit is obtained from the second coordination controller of the pure energy storage unit in the pure energy storage area through communication. B , that is, the remaining energy SOE of the Bth pure energy storage unit B According to the remaining energy of the photovoltaic energy storage unit , the remaining energy of the pure energy storage unit and the average remaining power of the power station , determine the actual power station residual energy deviation .

[0054] S502: Determine the average coordinated power of the power station according to the actual power station residual energy deviation and the preset power station residual energy total reference deviation.

[0055] In some embodiments, the average coordinated power of the power station can be determined according to the following calculation formula: :

[0056] in, ; Indicates the total reference deviation of the remaining energy of the power station; Indicates the allowable deviation of the remaining energy of the power station; Represents the average coordinated power coefficient of the energy management system.

[0057] Specifically, the power station remaining energy allowable deviation SOE is obtained from the client's user setting interface delt_base , get the maximum value of the power station's remaining energy SOE max , SOC minimum SOE min . According to the actual residual energy deviation of the power station and the preset total reference deviation of the remaining energy of the power station , determine the average coordinated power of the power station .

[0058] S503. The energy management system obtains the charge and discharge mode from the dispatch center and determines the charge and discharge power requirements of the photovoltaic energy storage unit and the pure energy storage unit based on the output power of all DCDC converters, the average coordinated power of the power station, and the preset reference charge and discharge power.

[0059] In some embodiments, if the charge / discharge mode is the discharge-permitted mode, the discharge power requirement of the current photovoltaic energy storage unit is determined based on the output power of all DCDC converters, the average coordinated power, and a preset reference discharge power, and based on the difference between the current remaining energy of the photovoltaic energy storage unit and the average remaining power of the power station. Simultaneously, the discharge power requirement of the current pure energy storage unit is determined based on the output power of all DCDC converters, the average coordinated power, and a preset reference discharge power, and based on the difference between the current remaining energy of the pure energy storage unit and the average remaining power of the power station. In this manner, the energy management system transmits the discharge power requirement and discharge mode of the current photovoltaic energy storage unit to the corresponding first coordination controller via a signal, and transmits the discharge power requirement and discharge mode of the current pure energy storage unit via a signal to the corresponding second coordination controller, and then returns to step S501.

[0060] If the charge-discharge mode is the charging-allowed mode, the charging power requirement of the current photovoltaic energy storage unit is determined based on the output power of all DCDC converters, the average coordinated power, and the preset reference charging power, as well as the difference between the average remaining power of the power station and the remaining energy of the current photovoltaic energy storage unit. Simultaneously, the charging power requirement of the current pure energy storage unit is determined based on the output power of all DCDC converters, the average coordinated power, and the preset reference charging power, as well as the difference between the average remaining power of the power station and the remaining energy of the current pure energy storage unit. In this manner, the energy management system transmits the charging power requirement and charging mode of the current photovoltaic energy storage unit to the corresponding first coordination controller via signaling, and transmits the charging power requirement and charging mode of the current pure energy storage unit via signaling to the corresponding second coordination controller, and then returns to step S501.

[0061] In this embodiment, key data such as the SOE and DCDC output power of the photovoltaic energy storage unit and the pure energy storage unit are transmitted in real time to ensure the coordination of energy management of various parts during operation. In addition, the residual energy deviation balance control strategy can realize energy scheduling of the photovoltaic energy storage area and the pure energy storage area, improve the storage efficiency of photovoltaic energy, and prevent excessive residual energy deviation between the various energy storage units. This increases the consistency between the various units and helps to extend the life of the energy storage battery.

[0062] In some embodiments, if the charge and discharge mode obtained from the dispatch center is the discharge-allowed mode, the discharge power requirement of the current photovoltaic energy storage unit is calculated according to the following formula: and the current discharge power requirement of the pure energy storage unit : ; ; in, is the preset reference discharge power; Indicates the total output power of all DCDC converters in the current photovoltaic energy storage unit; Represents the average coordinated power of the power station; A=1...N, N is the total number of photovoltaic energy storage units; B=1...M, M is the total number of pure energy storage units; represents the remaining energy of the A-th photovoltaic energy storage unit; represents the remaining energy of the Bth pure energy storage unit; Indicates the average remaining energy of the power station.

[0063] Specifically, the energy management system obtains the charge and discharge mode and reference discharge power from the dispatch center. If the charge and discharge mode is the allowable discharge mode, the discharge power requirement of each photovoltaic energy storage unit is determined according to the above formula. and the discharge power requirements of each pure energy storage unit .

[0064] In some embodiments, if the charging and discharging mode obtained from the dispatch center is the charging mode, the charging demand power of the current photovoltaic energy storage unit is calculated according to the following formula: and the current charging power requirement of pure energy storage units : ; ; in, is the preset reference charging power; Indicates the total output power of all DCDC converters in the current photovoltaic energy storage unit; Represents the average coordinated power of the power station; A=1...N, N is the total number of photovoltaic energy storage units; B=1...M, M is the total number of pure energy storage units; represents the remaining energy of the A-th photovoltaic energy storage unit; represents the remaining energy of the Bth pure energy storage unit; Indicates the average remaining energy of the power station.

[0065] Specifically, if the charging and discharging mode obtained from the dispatching center is the charging mode, the energy management system calculates the reference charging power POWER according to the grid price and the capacity of the entire photovoltaic power station. charge_sys Then, the charging power requirement of the photovoltaic energy storage unit is determined according to the above formula: and the charging power requirement of pure energy storage unit .

[0066] See Figure 6 , Figure 6 A flow chart of an energy management method for a photovoltaic energy storage system according to another embodiment of the present application is shown.

[0067] In some embodiments, the energy management method of the photovoltaic energy storage system of the present application further includes: S601: Obtain the remaining energy and average remaining energy of the first energy storage module in the current photovoltaic energy storage unit in real time, and determine the actual remaining energy deviation of the current photovoltaic energy storage unit.

[0068] In this embodiment, the actual remaining energy deviation of the current photovoltaic energy storage unit can be determined according to the following calculation formula: :

[0069] in, Indicates the remaining energy of the MAth first energy storage module in the current photovoltaic energy storage unit; Represents the average remaining energy of all first energy storage modules in the current photovoltaic energy storage unit; MA=1...L, where L is the total number of first energy storage modules in the current photovoltaic energy storage unit.

[0070] Specifically, the first coordination controller of the current photovoltaic energy storage unit obtains the remaining energy SOE of the MAth first energy storage module in the current photovoltaic energy storage unit through communication. MA , MA=1....L, L is the total number of the first energy storage modules in the current photovoltaic energy storage unit. In addition, to facilitate subsequent calculations, the first coordination controller of the current photovoltaic energy storage unit obtains the allowable deviation of the average remaining energy SOE inside the photovoltaic energy storage unit from the energy management system delt_base_A , and obtain the output power POWER of the DCDC converter in the current photovoltaic energy storage unit DCDC_MA According to the remaining energy of all the first energy storage modules in the current photovoltaic energy storage unit , the first coordination controller of the current photovoltaic energy storage unit converts the surplus energy SOE of the current photovoltaic energy storage unit into A The signal is uploaded to the energy management system, and the output power POWER of the DCDC converter in the current photovoltaic energy storage unit is DCDC_MA The signal is uploaded to the energy management system.

[0071] S602: Determine the average coordinated power of the current photovoltaic energy storage unit according to the actual remaining energy deviation in the current photovoltaic energy storage unit and a first preset average remaining energy reference deviation.

[0072] In this embodiment, the average coordinated power of the current photovoltaic energy storage unit can be determined according to the following calculation formula: :

[0073] in, ; Indicates the first preset average remaining energy reference deviation of the current photovoltaic energy storage unit; Indicates the allowable deviation of the average remaining energy in the current photovoltaic energy storage unit; Indicates the current residual energy deviation proportional coefficient of the photovoltaic energy storage unit.

[0074] S603: The current photovoltaic energy storage unit obtains a charge and discharge mode from the energy management system, and determines the charge and discharge required power of the first converter in the current photovoltaic energy storage unit based on the output power of the DCDC converter in the current photovoltaic energy storage unit, the average coordinated power of the current photovoltaic energy storage unit, and the charge and discharge required power.

[0075] In this embodiment, if the charge and discharge mode obtained from the energy management system is the discharge-allowed mode, the discharge power requirement of the MAth first converter in the current photovoltaic energy storage unit is calculated according to the following formula: ; .

[0076] in, Indicates the current discharge power requirement of the photovoltaic energy storage unit; Indicates the output power of the MAth DCDC converter in the current photovoltaic energy storage unit; Indicates the average coordinated power of the current photovoltaic energy storage unit; Indicates the remaining energy of the MAth first energy storage module in the current photovoltaic energy storage unit; Represents the average remaining energy of all first energy storage modules in the current photovoltaic energy storage unit; MA=1...L, where L is the total number of first energy storage modules in the current photovoltaic energy storage unit.

[0077] Specifically, the first coordination controller of the current photovoltaic energy storage unit sets the discharge demand power of the MAth first converter in the current photovoltaic energy storage unit to The discharge mode is transmitted to the MAth first converter of the current photovoltaic energy storage unit via a signal, and the process returns to step S601 to implement the remaining energy deviation balance control of each first energy storage module at the first coordination controller level.

[0078] Furthermore, if the charging and discharging mode obtained from the energy management system is the charging mode, the charging demand power of the MAth first converter in the current photovoltaic energy storage unit is calculated according to the following formula: ; ; in, Indicates the current charging power requirement of the photovoltaic energy storage unit.

[0079] Specifically, the first coordination controller of the current photovoltaic energy storage unit will charge the required power of the MAth first converter in the current photovoltaic energy storage unit. The charging mode is transmitted to the MAth first converter of the current photovoltaic energy storage unit via a signal, and the process returns to step S601 to implement the remaining energy deviation balancing control of each first energy storage module at the first coordination controller level.

[0080] In this embodiment, based on the residual energy deviation balance control strategy at the first coordination controller level, the charge and discharge power of each photovoltaic energy storage unit is dynamically adjusted by calculating the energy reference deviation and the average coordinated power, thereby preventing the risks brought by excessive charging and discharging of a single photovoltaic energy storage unit and improving the consistency between energy storage systems.

[0081] See Figure 7 , Figure 7 A flow chart of an energy management method for a photovoltaic energy storage system provided in another embodiment of the present application is shown.

[0082] In some embodiments, the energy management method of the photovoltaic energy storage system of the present application further includes the following steps: S701. Obtain the remaining energy and average remaining energy of the second energy storage module in the current pure energy storage unit in real time, and determine the actual remaining energy deviation of the current pure energy storage unit.

[0083] In this embodiment, the actual remaining energy deviation of the current pure energy storage unit can be determined according to the following calculation formula: :

[0084] in, Indicates the remaining energy of the MBth second energy storage module in the current pure energy storage unit; Represents the average remaining energy of all second energy storage modules in the current pure energy storage unit; MB=1...K, where K is the total number of second energy storage modules in the current pure energy storage unit.

[0085] Specifically, the second coordination controller of the current pure energy storage unit obtains the remaining energy SOE of the second energy storage module in the current pure energy storage unit through communication. MB To facilitate subsequent calculations, the second coordinated controller of the current pure energy storage unit also obtains the allowable deviation SOE of the average remaining energy within the pure energy storage unit of the pure energy storage area from the energy management system. delt_base_BAccording to the remaining energy of all second energy storage modules in the current pure energy storage unit The second coordinated controller converts the remaining energy SOE of the current pure energy storage unit into B The signal is uploaded to the energy management system.

[0086] S702 : Determine the average coordinated power of the current pure energy storage unit according to the actual remaining energy deviation in the current pure energy storage unit and the second preset average remaining energy reference deviation.

[0087] In this embodiment, the average coordinated power of the current pure energy storage unit can be determined according to the following calculation formula: :

[0088] in, ; Indicates the second preset average remaining energy reference deviation of the current pure energy storage unit; Indicates the allowable deviation of the average remaining energy in the current pure energy storage unit; Indicates the current residual energy deviation proportional coefficient of the pure energy storage unit.

[0089] S703: The current pure energy storage unit obtains a charge and discharge mode from the energy management system, and determines the charge and discharge required power of the second converter in the current pure energy storage unit according to the average coordinated power and the charge and discharge required power in the current pure energy storage unit.

[0090] In some embodiments, if the charge and discharge mode obtained from the energy management system is the discharge-allowed mode, the discharge power requirement of the MBth second converter in the current pure energy storage unit is calculated according to the following formula: ; .

[0091] in, Indicates the current discharge power requirement of the pure energy storage unit; Indicates the average coordinated power of the current pure energy storage unit; Indicates the remaining energy of the MBth second energy storage module in the current pure energy storage unit; Indicates the average remaining energy of all second energy storage modules in the current pure energy storage unit; MB=1... , is the total number of second energy storage modules in the current pure energy storage unit.

[0092] Specifically, the second coordination controller of the current pure energy storage unit will be based on the discharge power requirement of the MBth second converter in the current pure energy storage unit. The discharge mode is transmitted to the MBth second converter of the current photovoltaic energy storage unit via a signal, and the process returns to step S701 to implement the remaining energy deviation balance control of each second energy storage module at the second coordination controller level.

[0093] Furthermore, if the charging and discharging mode obtained from the energy management system is the charging mode, the charging power requirement of the MBth second converter in the current pure energy storage unit is calculated according to the following formula: : ; in, Indicates the current charging power requirement of the pure energy storage unit.

[0094] Specifically, the second coordination controller of the current pure energy storage unit will charge the MBth second converter in the current pure energy storage unit with the required power The charging mode is transmitted to the MBth second converter of the current pure energy storage unit via a signal, and the process returns to step S701 to implement the remaining energy deviation balancing control of each second energy storage module at the second coordination controller level.

[0095] In this embodiment, based on the residual energy deviation balance control strategy at the second coordination controller level, the charge and discharge power of each pure energy storage unit is dynamically adjusted by calculating the energy reference deviation and the average coordinated power, thereby preventing the risk of overcharging and discharging of a single pure energy storage unit and improving the consistency between energy storage systems.

[0096] In the energy management method of the photovoltaic energy storage system of this embodiment, the energy management strategy of hierarchical control includes a residual energy deviation balance control strategy based on the energy management system level and a residual energy deviation balance control strategy based on the coordination controller level. Through this energy management strategy, energy scheduling of the photovoltaic energy storage area and the pure energy storage area can be achieved, the storage efficiency of photovoltaic energy can be improved, and at the same time, the residual energy deviation between each energy storage unit is prevented from being too large, the consistency between each energy storage unit is increased, and the life of the energy storage battery is extended. In addition, by transmitting key data such as the charge and discharge power and SOE of the photovoltaic energy storage unit and the pure energy storage unit in real time, the coordination of energy management of each part during operation is ensured, and the average residual energy SOE target control of each energy storage unit is achieved; by calculating the energy reference deviation and the average coordinated power, the charge and discharge power of each energy storage unit is dynamically adjusted to prevent the risk of excessive charge and discharge of a single energy storage unit and improve the consistency between energy storage systems.

[0097] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A photovoltaic energy storage system, characterized in that: include: At least one photovoltaic energy storage unit, at least one pure energy storage unit, an energy management system and a high-voltage distribution cabinet; a DCDC converter is introduced into the photovoltaic energy storage unit to convert photovoltaic power generation into DC-DC; The photovoltaic energy storage unit is electrically connected to the high-voltage distribution cabinet to achieve a two-way flow of electric energy; the pure energy storage unit is electrically connected to the high-voltage distribution cabinet to achieve a two-way flow of electric energy; the high-voltage distribution cabinet is connected to the power grid; The remaining energy of the photovoltaic energy storage unit, the remaining energy of the pure energy storage unit, and the average remaining power of the power station are obtained in real time to determine the actual power station remaining energy deviation. The average coordinated power station power is determined based on the actual power station remaining energy deviation and a preset total reference deviation of the power station remaining energy. The energy management system obtains the charging and discharging mode from the dispatching center, and based on the output power of all the DCDC converters, the average coordinated power station power, and the preset reference charging and discharging power, manages the charging and discharging of the photovoltaic energy storage unit and the pure energy storage unit, determines the charging and discharging power requirements of the photovoltaic energy storage unit and the pure energy storage unit, and realizes the balance control of the remaining energy deviation.

2. The photovoltaic energy storage system according to claim 1, characterized in that: The photovoltaic energy storage unit includes a photovoltaic battery group, a DCDC converter, a first energy storage module, a first converter, a first transformer and a first coordination controller; The photovoltaic battery group is used to generate photovoltaic power and output electrical energy. After conversion by the DCDC converter, the electrical energy is output to the corresponding first energy storage module and the corresponding first converter, so that the first converter performs power conversion on the electrical energy and outputs it to the first transformer. The first transformer then boosts the electrical energy and transmits it to the high-voltage distribution cabinet. The first energy storage module is used to store or discharge energy. The first coordination controller is connected to the energy management system, and is used to control the DCDC converter, the first energy storage module and the first converter based on a residual energy deviation balance control strategy.

3. The photovoltaic energy storage system according to claim 1, characterized in that: The pure energy storage unit includes a second energy storage module, a second converter, a second transformer and a second coordination controller, wherein the second energy storage module is connected to the second converter; one side of the second converter is connected to the second transformer and the second coordination controller in sequence; and the second coordination controller is connected to the high-voltage distribution cabinet; The second energy storage module is used for storing or discharging energy; the second coordination controller is used for controlling the second energy storage module and the second converter based on a residual energy deviation balance control strategy.

4. The energy management method of a photovoltaic energy storage system according to any one of claims 1 to 3, characterized in that: If the charge and discharge mode obtained from the dispatch center is the discharge-allowed mode, the discharge power requirement of the photovoltaic energy storage unit is calculated according to the following formula: and the discharge power requirement of the current pure energy storage unit : ； ； in, is the preset reference discharge power; Indicates the total output power of all DCDC converters in the current photovoltaic energy storage unit; Represents the average coordinated power of the power station; A=1...N, N is the total number of photovoltaic energy storage units; B=1...M, M is the total number of pure energy storage units; represents the remaining energy of the A-th photovoltaic energy storage unit; represents the remaining energy of the Bth pure energy storage unit; Indicates the average remaining energy of the power station.

5. The energy management method of a photovoltaic energy storage system according to any one of claims 1 to 3, characterized in that: If the charging and discharging mode obtained from the dispatch center is the charging mode, the charging demand power of the current photovoltaic energy storage unit is calculated according to the following formula: and the charging power requirement of the current pure energy storage unit : ； ； in, is the preset reference charging power; Indicates the total output power of all DCDC converters in the current photovoltaic energy storage unit; Represents the average coordinated power of the power station; A=1...N, N is the total number of photovoltaic energy storage units; B=1...M, M is the total number of pure energy storage units; represents the remaining energy of the A-th photovoltaic energy storage unit; represents the remaining energy of the Bth pure energy storage unit; Indicates the average remaining energy of the power station.

6. The energy management method of a photovoltaic energy storage system according to any one of claims 1 to 3, characterized in that: Also includes: Acquire the remaining energy and average remaining energy of the first energy storage module in the photovoltaic energy storage unit in real time, and determine the actual remaining energy deviation of the photovoltaic energy storage unit; Determining the average coordinated power of the photovoltaic energy storage unit according to the actual remaining energy deviation in the photovoltaic energy storage unit and the first preset average remaining energy reference deviation; The current photovoltaic energy storage unit obtains the charging and discharging mode from the energy management system, and determines the charging and discharging required power of the first converter in the current photovoltaic energy storage unit based on the output power of the DCDC converter in the current photovoltaic energy storage unit, the average coordinated power of the current photovoltaic energy storage unit, and the charging and discharging required power.

7. The energy management method of the photovoltaic energy storage system according to claim 6, characterized in that: If the charge and discharge mode obtained from the energy management system is the discharge-allowed mode, the discharge power requirement of the MAth first converter in the current photovoltaic energy storage unit is calculated according to the following formula: ; ； If the charging and discharging mode obtained from the energy management system is the charging mode, the charging demand power of the MAth first converter in the current photovoltaic energy storage unit is calculated according to the following formula: ; ； in, Indicates the current discharge power requirement of the photovoltaic energy storage unit; Indicates the current charging power requirement of the photovoltaic energy storage unit; Represents the output power of the MAth DCDC converter in the current photovoltaic energy storage unit; Represents the average coordinated power of the current photovoltaic energy storage unit; Represents the remaining energy of the MAth first energy storage module in the current photovoltaic energy storage unit; Represents the average remaining energy of all first energy storage modules in the current photovoltaic energy storage unit; MA=1...L, where L is the total number of first energy storage modules in the current photovoltaic energy storage unit.

8. The energy management method of a photovoltaic energy storage system according to any one of claims 1 to 3, characterized in that: Also includes: Acquire the remaining energy and average remaining energy of the second energy storage module in the current pure energy storage unit in real time, and determine the actual remaining energy deviation of the current pure energy storage unit; Determining the average coordinated power of the current pure energy storage unit according to the actual remaining energy deviation in the current pure energy storage unit and the second preset average remaining energy reference deviation; The current pure energy storage unit obtains the charge and discharge mode from the energy management system, and determines the charge and discharge required power of the second converter in the current pure energy storage unit according to the average coordinated power and the charge and discharge required power in the current pure energy storage unit.

9. The energy management method of the photovoltaic energy storage system according to claim 8, characterized in that: If the charge and discharge mode obtained from the energy management system is the discharge-allowed mode, the discharge power requirement of the MBth second converter in the current pure energy storage unit is calculated according to the following formula: ; ； If the charging and discharging mode obtained from the energy management system is the charging mode, the charging power requirement of the MBth second converter in the current pure energy storage unit is calculated according to the following formula: ; ； in, Indicates the current discharge power requirement of the pure energy storage unit; Indicates the current charging power requirement of the pure energy storage unit; Indicates the average coordinated power of the current pure energy storage unit; Represents the remaining energy of the MBth second energy storage module in the current pure energy storage unit; Represents the average remaining energy of all second energy storage modules in the current pure energy storage unit; MB=1... , is the total number of second energy storage modules in the current pure energy storage unit.

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