High-voltage cascade network construction type energy storage hierarchical grid-connected control method and high-voltage cascade network construction type energy storage hierarchical grid-connected control system

Abstract

The invention relates to a high-voltage cascade network construction type energy storage hierarchical grid-connected control method and system, and belongs to the field of energy storage control and power system optimization. According to the method, a plurality of energy storage units are connected in a cascading manner, so that flexible expansion and efficient integration of the system are realized, and the method is suitable for power requirements of different scales. On the basis, a hierarchical control strategy is provided, and two hierarchical control methods of local control and global coordination are adopted. Local control performs real-time optimization management on each energy storage unit to ensure efficient operation of the energy storage unit; and the global coordination is dynamically adjusted based on the overall power grid state, the overall output of the energy storage system is optimized, and coordinated and consistent grid-connected control is realized. According to the method, through hierarchical control and dynamic adjustment, optimized operation of the energy storage system is realized, and the reliability and stability of the power system are enhanced.

Description

Technical Field

[0001] The invention relates to a high-voltage cascade grid-forming energy storage hierarchical grid-connected control method, belonging to the field of energy storage system optimization operation. Background Art

[0002] As the proportion of new energy applications in power systems gradually increases, the strong randomness and uncertainty of new energy will have an adverse impact on the safe operation of the power system. Equipping energy storage systems to cooperate with large-scale new energy grid connection is an effective solution. With the rapid development of energy storage technology, many control strategies based on different ideas have emerged. For different scales of power demand, the system can be flexibly expanded in a cascaded manner. It is of great significance to dynamically optimize the operation of energy storage systems based on the two levels of energy storage systems and energy storage units.

[0003] Energy storage systems are widely used in improving the flexibility of energy storage systems, improving the efficiency and reliability of energy storage systems, and promoting the large-scale application of renewable energy. With the rapid development of energy storage systems in power networks, the key research direction in the field of energy storage system control is to achieve flexible, efficient and dynamic operation of energy storage systems based on their own structure and external demand. At present, the flexibility and dynamic performance of the control methods for energy storage systems are poor. The control methods do not well integrate the structure of the energy storage system itself with the external power demand to match the output of the energy storage unit, and fail to optimize the control of the energy storage system while quickly and dynamically responding to the grid demand.

[0004] There are currently two issues that need further research: ① Based on the different scales of power demand in the power grid, realize flexible and efficient control of the energy storage system by cascading multiple energy storage unit modules. ② Improve the existing control method and establish a hierarchical control method based on local control and global coordination, realize the optimal management of energy storage units by local control, and realize the dynamic adjustment of energy storage systems by global coordination. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems and propose a high-voltage cascade grid-type energy storage hierarchical grid-connected control method. The present invention adopts a cascade method of multiple energy storage units to achieve flexible expansion and efficient integration of the system, and combines a two-layer control method based on local control and global control to coordinate the optimized operation of the energy storage system. It can achieve more flexible and efficient optimization control of the energy storage system, and provide a theoretical basis and practical method for the grid-connected control of multiple high-voltage cascade grid-type energy storage.

[0006] In a first aspect, the present invention provides a high-voltage cascade grid-connected energy storage hierarchical grid-connected control method, comprising: S1, connecting multiple energy storage units in a cascade manner to form an energy storage system; S2, identify and analyze the demand for energy storage systems in power networks of different sizes; S3, adjusting the output power of each energy storage unit according to the demand of the power network for the energy storage system; S4, check whether the current energy storage unit output has achieved local optimization; if not, return to step S3 and continue to adjust the output; if it has been optimized, proceed to the next step; S5, controlling the energy storage unit to achieve local optimal output; S6, dynamically adjusts the output of the energy storage system according to the overall demand of the power grid; S7, check whether the output of the energy storage system meets the needs of the power grid; if not, return to step S6 and continue to adjust; if satisfied, proceed to the next step; S8, finally the overall output power of the energy storage system is obtained and coordinated grid-connected control is performed.

[0007] As a further improvement of the present invention, the multiple energy storage units are connected in a cascade manner to form an energy storage system, which is to connect the multiple energy storage units in a cascade manner using a high-voltage cascade modular method.

[0008] As a further improvement of the present invention, the multiple energy storage units are connected in a cascade manner to form an energy storage system, and the number of cascades is determined based on an output quantity model of high-voltage cascade energy storage modules.

[0009] As a further improvement of the present invention, the method for establishing the output quantity model of the high-voltage cascade energy storage module includes: Establish a maximum output constraint model for high-voltage cascade energy storage modules, including the maximum available output of the energy storage module when charging is required and the maximum available output of the energy storage unit when discharging is required; The maximum available output of the energy storage module when charging is required is:

[0010] In the formula, S OC，i For the i The current state of charge of each energy storage unit; E i For the i The maximum capacity of an energy storage unit; Δ k For charging time; The maximum available output of the energy storage unit when discharging is required is:

[0011] Based on the maximum output constraint model of high-voltage cascade energy storage modules, a cascade quantity model of high-voltage cascade energy storage modules is established, which specifically includes: The number of cascaded energy storage units should meet the charging requirements:

[0012] in, N is the number of cascaded energy storage modules; P re To meet the electricity demand from the outside; When discharging, the number of cascaded energy storage units should meet the following requirements:

[0013] in, i For the i Energy storage unit.

[0014] As a further improvement of the present invention, adjusting the output power of each energy storage unit according to the demand of the power network for the energy storage system is an output model of the battery module in the energy storage unit.

[0015] As a further improvement of the present invention, the method for establishing the output model of the battery module in the energy storage unit includes: Establish the battery module output constraint model in the energy storage module, including: The maximum available output of the battery module when charging is required:

[0016] In the formula, S OC，ij For the i Energy storage unit j The current state of charge of each battery module; E ij For the i Energy storage unit j The maximum capacity of a battery module; Δ k For charging time; The maximum available output of the energy storage unit when discharging is required:

[0017] Output constraints based on the energy storage module’s own limits:

[0018] In the formula, P ij,max For the i In the energy storage module j Maximum available power of each battery module; Battery module output constraints based on energy storage module output:

[0019] In the formula, Mis the number of battery modules in the energy storage module; Establish the output objective function model of the energy storage module in the energy storage system, including: The state of charge model of the battery module after output is:

[0020] In the formula, S OC,i ( k )for k Moment i In the energy storage module j The state of charge of each battery module; P i ( k )for k Moment i In the energy storage module j The output power of each battery module, E is the rated capacity of the energy storage battery module; Mathematical model of the maximum and minimum state of charge of the battery module after output:

[0021] In the formula, S OC,i1 ( k+ 1), S OC,i2 ( k+ 1),…, S OC,ij ( k+ 1) are respectively i The first, second and j Battery modules in k +1 moment SOC;

[0022] In the formula, S OC_i,max ( k +1) k +1 moment i The maximum SOC value of the battery module in each energy storage module, S OC_i,min ( k +1) k +1 moment i The minimum SOC value of the battery module in the energy storage module.

[0023] As a further improvement of the present invention, dynamically adjusting the output of the energy storage system according to the overall demand of the power grid is to dynamically adjust the overall output model of the energy storage system.

[0024] As a further improvement of the present invention, the method for establishing the overall output model of the energy storage system includes: Establish the output constraint model of energy storage module in energy storage system: Output constraints based on the energy storage module’s own limits:

[0025] In the formula, P i,max is the maximum available power of the energy storage module; Energy storage module output constraints based on grid demand:

[0026] Establish the output objective function model of energy storage module in energy storage system: The state of charge model of the energy storage unit after output is:

[0027] In the formula, S OC,i ( k )for k Moment i The charge state of each energy storage module, P i ( k )for k Moment i The output power of each energy storage module is E 0 is the rated capacity of the energy storage unit; Mathematical model of maximum and minimum state of charge of energy storage unit after output:

[0028] In the formula, S OC,1 ( k+ 1), S OC,2 ( k+ 1),…, S OC,i ( k+ 1) respectively 1st, 2nd and i Energy storage modules in k +1 moment SOC;

[0029] In the formula, S OC,max ( k +1) k +1 time the maximum SOC value of the energy storage module, S OC,max (k +1) k +1 is the minimum SOC value in the energy storage module.

[0030] In a second aspect, the present invention provides a high-voltage cascade grid-connected energy storage hierarchical grid-connected control system, comprising: A cascade module is used to connect multiple energy storage units in a cascade manner to form an energy storage system; The local control module is used to identify and analyze the needs of power networks of different sizes for energy storage systems; adjust the output power of each energy storage unit according to the needs of the power network for the energy storage system; check whether the current energy storage unit output has achieved local optimization; if not, return to continue adjusting the output; control the energy storage unit to achieve the local optimal output; The global coordination module is used to dynamically adjust the output of the energy storage system according to the overall needs of the power grid; check whether the output of the energy storage system meets the needs of the power grid; if not, continue to adjust; and finally coordinate and coordinate the grid-connected control.

[0031] In a third aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the high-voltage cascade grid-type energy storage hierarchical grid-connected control method when executing the computer program.

[0032] In a fourth aspect, the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the high-voltage cascade grid-type energy storage hierarchical grid-connected control method is implemented.

[0033] In a fifth aspect, the present invention provides a computer program product, which includes computer instructions, and the computer instructions instruct a computer to execute the high-voltage cascade grid-type energy storage hierarchical grid-connected control method.

[0034] The beneficial effects of the present invention compared with the prior art are as follows: Compared with the prior art, the beneficial effects of the present invention are as follows: comprehensively considering the external power demand and the structure of the energy storage system itself, reasonably allocating the output quantity of the energy storage units in a cascade manner, and based on the hierarchical idea, dividing the control of the energy storage system into local control and global control, optimizing the management of the energy storage units in a local control manner, and optimizing the overall output of the energy storage system in a global control manner, providing a method for the flexible, efficient and dynamic operation of the energy storage system.

[0035] The present invention adopts a high-voltage cascade modular design. By connecting multiple energy storage units in a cascade manner, the system can be flexibly expanded and efficiently integrated, which is suitable for power demands of different scales. Two hierarchical control methods, local control and global coordination, are adopted. Local control performs real-time optimization management for each energy storage unit to ensure its efficient operation; global coordination performs dynamic adjustment based on the overall power grid status, optimizes the overall output of the energy storage system, and realizes coordinated grid-connected control. This method realizes the optimized operation of the energy storage system through hierarchical control and dynamic adjustment, and enhances the reliability and stability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the embodiments of the present invention or the drawings of related technical solutions in the prior art are introduced below. It should be understood that the drawings introduced below are only for the convenience of clearly describing some embodiments of the technical solutions of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 It is a flow chart of a high-voltage cascade grid-connected energy storage hierarchical grid-connected control method; Figure 2 It is a framework diagram of the cascading and hierarchical control of energy storage unit modules. DETAILED DESCRIPTION The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limitations of the present invention. For the step numbers in the following embodiments, they are only provided for the convenience of explanation, and the order between the steps is not limited in any way, and the execution order of each step in the embodiment can be adaptively adjusted according to the understanding of those skilled in the art.

[0039] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0040] The purpose of the present invention is to solve the above problems. The first purpose of the present invention is to provide a high-voltage cascade grid-type energy storage hierarchical grid-connected control method, comprising the following steps: S1, connecting multiple energy storage units in a cascade manner to form an energy storage system; S2, identify and analyze the demand for energy storage systems in power networks of different sizes; S3, adjusting the output power of each energy storage unit according to the demand of the power network for the energy storage system; S4, check whether the current energy storage unit output has achieved local optimization; if not, return to step S3 and continue to adjust the output; if it has been optimized, proceed to the next step; S5, controlling the energy storage unit to achieve local optimal output; S6, dynamically adjusts the output of the energy storage system according to the overall demand of the power grid; S7, check whether the output of the energy storage system meets the needs of the power grid; if not, return to step S6 and continue to adjust; if satisfied, proceed to the next step; S8, finally the overall output power of the energy storage system is obtained and coordinated grid-connected control is performed.

[0041] As an example, the high-voltage cascade grid-type energy storage control method has certain complexity, which is mainly manifested in: based on the power demand of different scales of the power network, the energy storage system is flexibly expanded and efficiently integrated, and from the perspective of improving the reliable and stable operation of the energy storage system, the energy storage system is hierarchically controlled based on the state of the power grid, the energy storage system is dynamically adjusted, and the operation mode of the energy storage system is optimized. The present invention solves the problem of insufficient dynamic performance of the traditional energy storage system control method and enhances the flexibility and efficiency of the energy storage system.

[0042] Furthermore, the method of the present invention is a multi-type energy storage application value assessment method based on market analysis. The basic idea is: for different scales of power demand in the power grid, multiple energy storage units are cascaded using a high-voltage cascade modular method. In view of the problem of insufficient dynamic performance of traditional energy storage system control methods, it is proposed to optimize the management of energy storage units based on local control, and dynamically adjust the energy storage system in a globally coordinated manner based on the power grid status, providing a control method for efficient and dynamic control of energy storage systems.

[0043] Furthermore, the technical solution provided by the present invention is: to control the operation of the energy storage system based on modular cascade and hierarchical control methods, and to ensure that the control method can realize flexible, efficient and dynamic operation of the energy storage system. By connecting multiple energy storage units in a cascade manner, the flexible expansion and efficient integration of the system are realized, which is suitable for power demand of different scales. On this basis, a hierarchical control strategy is proposed, which adopts two-level control methods: local control and global coordination. Local control performs real-time optimization management for each energy storage unit to ensure its efficient operation; global coordination performs dynamic adjustment based on the overall power grid status, optimizes the overall output of the energy storage system, and realizes coordinated and consistent grid-connected control. This method realizes the optimized operation of the energy storage system and enhances the reliability and stability of the power system through hierarchical control and dynamic adjustment.

[0044] Among them, the energy storage system adopts a high-voltage cascade modular design method, referring to the power demand of different scales of the power system, and increases the scalability and flexibility of the energy storage system by connecting multiple energy storage units in a cascade manner to meet the processing requirements.

[0045] Based on the hierarchical control concept, a hierarchical control strategy for grid-type energy storage is proposed. Based on the power demand and the state of the energy storage system itself, the two-level control methods of local control and global coordination are used to achieve efficient and dynamic operation of the energy storage system, thereby enhancing the reliability and stability of the power system.

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] based on Figure 1 The specific steps of the embodiment of the present invention are as follows: Start: S1, cascading multiple energy storage units: connecting multiple energy storage units in a cascade manner to form an energy storage system.

[0048] S2, Demand for power networks of different sizes: Identify and analyze the demand for energy storage systems for power networks of different sizes.

[0049] S3, adjust the output of each energy storage unit: adjust the output power of each energy storage unit according to the needs of the power network.

[0050] S4, Is local optimization achieved? Check whether the current energy storage unit output has achieved local optimization.

[0051] No: If not optimized, return to the step "Adjust the output of each energy storage unit" and continue to adjust the output.

[0052] Yes: If optimized, proceed to the next step.

[0053] S5, realize local optimization control: control the energy storage unit to achieve local optimal output.

[0054] S6, based on the overall grid demand: consider the needs of the entire grid, not just the local needs.

[0055] Dynamically adjust the output of the energy storage system: Dynamically adjust the output of the energy storage system according to the overall needs of the power grid.

[0056] S7, Meet grid demand? Check whether the output of the energy storage system meets the grid demand.

[0057] No: If not satisfied, return to the step of "Dynamically Adjusting the Energy Storage System Output" and continue to adjust.

[0058] Yes: If satisfied, proceed to the next step.

[0059] S8, obtain the overall output of the energy storage system: determine the overall output power of the energy storage system to meet the needs of the power grid.

[0060] End: The energy storage system has been optimized according to grid demand and outputs the required power.

[0061] like Figure 2 As shown in the figure, multiple energy storage units are cascaded and optimized and adjusted according to the different needs of the power grid. Through local and overall optimization, the energy storage system can effectively meet the dynamic needs of the power grid.

[0062] Among them, multiple energy storage units are connected in a cascade manner, and the output quantity model of the high-voltage cascade energy storage module is used for confirmation. The method for establishing the output quantity model of the high-voltage cascade energy storage module is as follows: Establish a high-voltage cascade energy storage module output quantity model; (1) Establish a maximum output constraint model for high-voltage cascade energy storage modules.

[0063] The maximum available output of the energy storage module when charging is required: (1) In the formula, S OC，i For the i The current state of charge of each energy storage unit; E i For the i The maximum capacity of an energy storage unit; Δ k For charging time.

[0064] The maximum available output of the energy storage unit when discharging is required: (2) (2) Establish a cascade quantity model for high-voltage cascade energy storage modules.

[0065] The number of cascaded energy storage units should meet the charging requirements: (3) in, N is the number of cascaded energy storage modules; P re To meet the electricity demand from outside.

[0066] When discharging, the number of cascaded energy storage units should meet the following requirements: (4) The method of dynamically adjusting the output of the energy storage system according to the overall demand of the power grid is to dynamically adjust the overall output model of the energy storage system. The method of establishing the overall output model of the energy storage system includes: According to the overall power grid status, establish the overall output model of the energy storage system (3) Establish the output constraint model of energy storage modules in the energy storage system: Output constraints based on the energy storage module’s own limits: (5) In the formula, P i,max is the maximum available power of the energy storage module.

[0067] Energy storage module output constraints based on grid demand: (6) (4) Establish the output objective function model of the energy storage module in the energy storage system: The state of charge model of the energy storage unit after output is: (7) In the formula, S OC,i ( k )for k Moment i The charge state of each energy storage module, P i ( k )for k Moment i The output power of each energy storage module is E 0 is the rated capacity of the energy storage unit.

[0068] Mathematical model of maximum and minimum state of charge of energy storage unit after output: (8) In the formula, S OC,1 ( k+ 1), S OC,2 ( k+ 1),…, S OC,i ( k+ 1) respectively 1st, 2nd and i Energy storage modules in k +1 SOC at the moment.

[0069] (9) In the formula, S OC,max ( k +1) k +1 time the maximum SOC value of the energy storage module, S OC,max ( k +1)k +1 is the minimum SOC value in the energy storage module at time.

[0070] The method of adjusting the output power of each energy storage unit according to the demand of the power network for the energy storage system is the output model of the battery module in the energy storage unit. The method of establishing the output model of the battery module in the energy storage unit includes: Based on the output of each energy storage unit, the battery module output model in the energy storage unit is established: (5) Establish the battery module output constraint model in the energy storage module: The maximum available output of the battery module when charging is required: (10) In the formula, S OC，ij For the i Energy storage unit j The current state of charge of each battery module; E ij For the i Energy storage unit j The maximum capacity of a battery module; Δ k For charging time.

[0071] The maximum available output of the energy storage unit when discharging is required: (11) Output constraints based on the energy storage module’s own limits: (12) In the formula, P ij,max For the i In the energy storage module j The maximum available power of each battery module.

[0072] Battery module output constraints based on energy storage module output: (13) In the formula, M is the number of battery modules in the energy storage module.

[0073] (6) Establish the output objective function model of the energy storage module in the energy storage system: The state of charge model of the battery module after output is: (14) In the formula, S OC,i ( k )for k Moment i In the energy storage module j The state of charge of each battery module;P i ( k )for k Moment i In the energy storage module j The output power of each battery module, E It is the rated capacity of the energy storage battery module.

[0074] Mathematical model of the maximum and minimum state of charge of the battery module after output: (15) In the formula, S OC,i1 ( k+ 1), S OC,i2 ( k+ 1),…, S OC,ij ( k+ 1) are respectively i The first, second and j Battery modules in k +1 SOC at the moment.

[0075] (16) In the formula, S OC_i,max ( k +1) k +1 moment i The maximum SOC value of the battery module in each energy storage module, S OC_i,min ( k +1) k +1 moment i The minimum SOC value of the battery module in the energy storage module.

[0076] The second object of the present invention is to provide a high voltage cascade grid-connected energy storage hierarchical grid-connected control system, comprising: A cascade module is used to connect multiple energy storage units in a cascade manner to form an energy storage system; The local control module is used to identify and analyze the needs of power networks of different sizes for energy storage systems; adjust the output power of each energy storage unit according to the needs of the power network for the energy storage system; check whether the current energy storage unit output has achieved local optimization; if not, return to continue adjusting the output; control the energy storage unit to achieve the local optimal output; The global coordination module is used to dynamically adjust the output of the energy storage system according to the overall needs of the power grid; check whether the output of the energy storage system meets the needs of the power grid; if not, continue to adjust; and finally coordinate and coordinate the grid-connected control.

[0077] The third object of the embodiment of the present invention is to provide an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the high-voltage cascade grid-type energy storage hierarchical grid-connected control method when executing the computer program. It also includes a communication interface and a bus.

[0078] The fourth objective of an embodiment of the present invention is to provide a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the high-voltage cascade grid-type energy storage hierarchical grid-connected control method is implemented.

[0079] A fifth objective of an embodiment of the present invention is to provide a computer program product, the computer program product comprising computer instructions, the computer instructions instructing a computer to execute the high-voltage cascade grid-type energy storage hierarchical grid-connected control method.

[0080] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0081] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0082] The present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, readable storage media, optical storage, etc.) containing computer-usable program codes.

[0083] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0084] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A high-voltage cascade grid-connected energy storage hierarchical grid-connected control method, characterized in that: include: S1, connecting multiple energy storage units in a cascade manner to form an energy storage system; S2, identify and analyze the demand for energy storage systems in power networks of different sizes; S3, adjusting the output power of each energy storage unit according to the demand of the power network for the energy storage system; S4, check whether the current energy storage unit output has achieved local optimization; if not, return to step S3 and continue to adjust the output; if it has been optimized, proceed to the next step; S5, controlling the energy storage unit to achieve local optimal output; S6, dynamically adjusts the output of the energy storage system according to the overall demand of the power grid; S7, check whether the output of the energy storage system meets the needs of the power grid; if not, return to step S6 and continue to adjust; if satisfied, proceed to the next step; S8, finally the overall output power of the energy storage system is obtained and coordinated grid-connected control is performed.

2. A high-voltage cascade grid-connected energy storage hierarchical grid-connected control method according to claim 1, characterized in that: The multiple energy storage units are connected in a cascade manner to form an energy storage system, which is to connect the multiple energy storage units in a cascade manner using a high-voltage cascade modular method.

3. A high-voltage cascade grid-connected energy storage hierarchical grid-connected control method according to claim 1, characterized in that: The multiple energy storage units are connected in a cascade manner to form an energy storage system, and the number of cascades is determined based on an output quantity model of high-voltage cascade energy storage modules.

4. A high-voltage cascade grid-connected energy storage hierarchical grid-connected control method according to claim 3, characterized in that: The method for establishing the output quantity model of the high-voltage cascade energy storage module includes: Establish a maximum output constraint model for high-voltage cascade energy storage modules, including the maximum available output of the energy storage module when charging is required and the maximum available output of the energy storage unit when discharging is required; The maximum available output of the energy storage module when charging is required is: In the formula, S OC，i For the i The current state of charge of each energy storage unit; E i For the i The maximum capacity of an energy storage unit; Δ k For charging time; The maximum available output of the energy storage unit when discharging is required is: Based on the maximum output constraint model of high-voltage cascade energy storage modules, a cascade quantity model of high-voltage cascade energy storage modules is established, which specifically includes: The number of cascaded energy storage units should meet the charging requirements: in, N is the number of cascaded energy storage modules; P re To meet the electricity demand from the outside; When discharging, the number of cascaded energy storage units should meet the following requirements: in, i For the i Energy storage unit.

5. A high-voltage cascade grid-connected energy storage hierarchical grid-connected control method according to claim 1, characterized in that: The adjustment of the output power of each energy storage unit according to the demand of the power network for the energy storage system is the output model of the battery module in the energy storage unit.

6. A high-voltage cascade grid-connected energy storage hierarchical grid-connected control method according to claim 5, characterized in that: The method for establishing the battery module output model in the energy storage unit includes: Establish the battery module output constraint model in the energy storage module, including: The maximum available output of the battery module when charging is required: In the formula, S OC，ij For the i Energy storage unit j The current state of charge of each battery module; E ij For the i Energy storage unit j The maximum capacity of a battery module; Δ k For charging time; The maximum available output of the energy storage unit when discharging is required: Output constraints based on the energy storage module’s own limits: In the formula, P ij,max For the i In the energy storage module j Maximum available power of each battery module; Battery module output constraints based on energy storage module output: In the formula, M is the number of battery modules in the energy storage module; Establish the output objective function model of the energy storage module in the energy storage system, including: The state of charge model of the battery module after output is: In the formula, S OC,i ( k )for k Moment i In the energy storage module j The state of charge of each battery module; P i ( k )for k Moment i In the energy storage module j The output power of each battery module, E is the rated capacity of the energy storage battery module; Mathematical model of the maximum and minimum state of charge of the battery module after output: In the formula, S OC,i1 ( k+ 1), S OC,i2 ( k+ 1),…, S OC,ij ( k+ 1) are respectively i The first, second and j Battery modules in k +1 SOC at the moment; In the formula, S OC_i,max ( k +1) k +1 moment i The maximum SOC value of the battery module in each energy storage module, S OC_i,min ( k +1) k +1 moment i The minimum SOC value of the battery module in the energy storage module.

7. A high voltage cascade grid-connected energy storage hierarchical grid-connected control method according to claim 1, characterized in that: The dynamically adjusting the output of the energy storage system according to the overall demand of the power grid is to dynamically adjust the overall output model of the energy storage system.

8. A high-voltage cascade grid-connected energy storage hierarchical grid-connected control method according to claim 7, characterized in that: The method for establishing the overall output model of the energy storage system includes: Establish the output constraint model of energy storage module in energy storage system: Output constraints based on the energy storage module’s own limits: In the formula, P i,max is the maximum available power of the energy storage module; Energy storage module output constraints based on grid demand: Establish the output objective function model of energy storage module in energy storage system: The state of charge model of the energy storage unit after output is: In the formula, S OC,i ( k )for k Moment i The charge state of each energy storage module, P i ( k )for k Moment i The output power of each energy storage module is E 0 is the rated capacity of the energy storage unit; Mathematical model of maximum and minimum state of charge of energy storage unit after output: In the formula, S OC,1 ( k+ 1), S OC,2 ( k+ 1),…, S OC,i ( k+ 1) respectively 1st, 2nd and i Energy storage modules in k +1 SOC at the moment; In the formula, S OC,max ( k +1) k +1 time the maximum SOC value of the energy storage module, S OC,max ( k +1) k +1 is the minimum SOC value in the energy storage module.

9. A high voltage cascade grid-connected energy storage hierarchical grid-connected control system, characterized in that: include: A cascade module is used to connect multiple energy storage units in a cascade manner to form an energy storage system; The local control module is used to identify and analyze the needs of power networks of different sizes for energy storage systems; adjust the output power of each energy storage unit according to the needs of the power network for the energy storage system; check whether the current energy storage unit output has achieved local optimization; if not, return to continue adjusting the output; control the energy storage unit to achieve the local optimal output; The global coordination module is used to dynamically adjust the output of the energy storage system according to the overall needs of the power grid; check whether the output of the energy storage system meets the needs of the power grid; if not, continue to adjust; and finally coordinate and coordinate the grid-connected control.

10. An electronic device, characterized in that: It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, it implements the high-voltage cascade grid-type energy storage hierarchical grid-connected control method as described in any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the high-voltage cascade grid-type energy storage hierarchical grid-connected control method according to any one of claims 1 to 8 is implemented.

12. A computer program product, comprising computer instructions, characterized in that: The computer instructions instruct the computer to execute the high-voltage cascade grid-connected energy storage hierarchical grid-connected control method as described in any one of claims 1-8.

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