Small-capacity digital battery energy storage system large-scale integration method and system

Abstract

The application provides a small-capacity digital battery energy storage system large-scale integration method and system, and belongs to the technical field of digital energy storage.The system comprises a battery operation system, a hardware control system and digital batteries, wherein the hardware control system comprises a central processor and a reconfigurable battery network, further comprises a reconfigurable battery network controller connected with the central processor, a global energy controller, a decentralized coordination controller, a system discharging circuit and a system charging circuit, the system charging circuit is connected with each digital battery system in the reconfigurable battery network and an input side, the system discharging circuit is connected with each digital battery system in the reconfigurable battery network and an output side, the reconfigurable battery network is combined and connected by the digital batteries, and the reconfigurable battery network is controlled by the reconfigurable battery network controller and the global energy controller.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of digital energy storage, in particular to a small-capacity digital battery energy storage system large-scale integration method and system. BACKGROUND

[0002] With the increasing demand for large-capacity battery energy storage system, the battery monomers with low voltage and capacity level are usually connected in a fixed series-parallel manner in the order of "millions". The common practice is to first connect the battery monomers in series and parallel to form a battery module, and then connect the battery modules in series and parallel to form a battery cluster, and then connect the battery cluster to the AC side through a power conversion system to realize grid connection and improve the voltage and current level of the energy storage system.

[0003] In a hundred megawatt-level energy storage power station and a megawatt-level distributed energy storage system, the common practice is to first connect the battery monomers in series and parallel to form a battery module, and then connect the battery modules in series and parallel to form a battery cluster, and then connect the battery cluster to the AC side through a power conversion system to realize grid connection and improve the voltage and current level of the energy storage system. The types and quantities of intermediate state variables and intermediate control variables required for observation and adjustment during the operation of the energy storage system are quite large. If all the state variables and control variables of the battery modules are processed centrally, the delay and error accumulation caused by the large amount of calculation will directly affect the response speed and control accuracy of the entire energy storage system. In addition, due to the inherent differences between the battery monomers, the battery modules composed of the battery monomers also have differences between each other, and direct fixed series-parallel integration will amplify these differences, making the centralized management of the energy storage system less efficient and less safe, reducing the efficiency, reliability and safety of the large-scale energy storage system, and making it difficult to flexibly realize the diversity of application requirements in vertical industries. SUMMARY

[0004] Therefore, the present application provides a small-capacity digital battery energy storage system large-scale integration method and system, which improves the control strategy of the large-scale energy storage system for the battery monomers, improves the response speed and control accuracy of the large-scale energy storage system, and improves the working efficiency, reliability and safety of the large-scale energy storage system.

[0005] The technical solution adopted by the embodiment of the present application to solve the technical problems is:

[0006] A small-capacity digital battery energy storage system large-scale integration system, the large-scale integration system comprising: a battery operation system, a hardware control system and a digital battery, wherein:

[0007] The hardware control system comprises a central processor and a reconfigurable battery network, and further comprises a reconfigurable battery network controller, a global energy controller, a decentralized coordination controller, a digital battery system discharging circuit and a digital battery system charging circuit connected with the central processor, wherein the digital battery system charging circuit is connected with each digital battery system in the reconfigurable battery network and an input side, the digital battery system discharging circuit is connected with each digital battery system in the reconfigurable battery network and an output side, and the reconfigurable battery network is controlled by the reconfigurable battery network controller and the global energy controller.

[0008] The battery operation system is embedded in the central processor, and the battery operation system supports an open API.

[0009] The reconfigurable battery network is coupled with an m-number of digital energy storage subsystems and a high-frequency power electronic switch array, the reconfigurable battery network controller manages the electronic switch state of the high-frequency power electronic switch array according to the state information of each digital energy storage subsystem, and each high-frequency power electronic switch in the high-frequency power electronic switch array is located at a node between a system DC bus and a common DC bus of each digital energy storage subsystem.

[0010] Each digital energy storage subsystem is connected with one decentralized coordination controller, and the message interfaces of the global energy controller, the decentralized coordination controllers and the digital energy storage subsystems are connected to a system message bus, the signals in the system message bus are time-division multiplexing signals, the global energy controller and the decentralized coordination controllers control the real-time output of each digital energy storage subsystem through a rolling horizon control strategy, and the digital energy storage subsystem independently regulates the output of each low-voltage digital battery system in the internal digital energy storage subsystem to form an autonomous decentralized control structure.

[0011] The digital energy storage subsystem is flexibly aggregated by n-number of low-voltage digital battery systems with small capacity through a power electronic converter, the digital energy storage subsystem adopts a distributed energy-on-demand control strategy for each level of the low-voltage digital battery system in the internal digital energy storage subsystem, and the low-voltage digital battery system is composed of p-number of digital battery strings in series or parallel, and the low-voltage digital battery system adopts a charging and discharging voltage active adjustment and parameter adaptive control strategy for each digital battery in the internal low-voltage digital battery system.

[0012] Preferably, the reconfigurable battery network controller is composed of m-number of subsystem switching control units, each of the m-number of subsystem switching control units is connected with one high-frequency power electronic switch and communicates with an internal CAN bus of the reconfigurable battery network controller.

[0013] The digital energy storage subsystem has a built-in embedded sensing device, which is connected to the digital energy control chip of the subsystem switching control unit. The sensor types in the embedded sensing device include at least a subsystem voltage acquisition device and a temperature sensor.

[0014] The digital energy control chip calculates the state information of the digital energy storage subsystem based on the sampling data of the embedded sensing device, and controls the switching state of the high-frequency power electronic switch based on the state information of the digital energy storage subsystem to control the switching state of the digital energy storage subsystem. The state information of the digital energy storage subsystem includes the battery state of charge (SOC) and the battery state of health (SOH). The battery state of charge (SOC) is calculated based on the voltage sampling data of the subsystem voltage collector, and the battery state of health (SOH) is calculated based on the temperature sampling data of the subsystem voltage collector.

[0015] Preferably, the control strategy of the reconfigurable battery network controller for the common DC bus of each of the digital energy storage subsystems is a centralized voltage regulation control strategy. The control system of the centralized voltage regulation strategy consists of an outer voltage loop and an inner current loop. The control output of the outer voltage loop is the command current of the inner current loop. The inner current loop has feedforward control and decoupling control to accelerate the dynamic response of the system.

[0016] Preferably, the energy-on-demand control strategy of the digital energy storage subsystem includes constant voltage mode, constant current mode, and constant power mode.

[0017] Preferably, the global energy controller, controlled by the central processing unit, is used to send the system's real-time output requirement at time k+1 to the system message bus.

[0018] The i-th distributed coordination controller obtains the actual output {Y} of all the digital energy storage subsystems at time k through the system message bus. 1,k ,Y 2,k ,...,Y m,k}, the aforementioned Under the current global output control mode of the large-scale integrated system, according to {Y 1,k ,Y 2,k ,...,Y m,k}, the aforementioned Actual system output at time k Calculate the control input variable u of the i-th digital energy storage subsystem at time k+1. i (k+1), where, The control input variable u at time k+1 i (k+1) is input to the i-th digital energy storage subsystem;

[0019] The i-th digital energy storage subsystem is configured to send the state information of the i-th digital energy storage subsystem to the system message bus according to the u i (k+1) independently regulates the output of each low-voltage digital battery system in the i-th digital energy storage subsystem, and at the k+1 moment, the actual output Y i,k+1 to the system message bus.

[0020] Preferably, the global output control mode includes an external electrical system transient response mode, an external electrical system real-time scheduling mode, and a digital energy storage system energy management mode.

[0021] Preferably, the state equation of the large-scale integrated system is described as:

[0022]

[0023] wherein x i (k) is the state variable of the i-th digital energy storage subsystem controlled at the k moment, and matrix A and matrix B are matrix parameters.

[0024] The application also provides a large-scale integration method of a small-capacity digital battery energy storage system, comprising:

[0025] A reconfigurable battery network is constructed, which is coupled by m digital energy storage subsystems and a high-frequency power electronic switch array, each high-frequency power electronic switch in the high-frequency power electronic switch array is located at a node between a system DC bus and a common DC bus of each digital energy storage subsystem, each digital energy storage subsystem is flexibly connected and aggregated by n small-capacity low-voltage digital battery systems through a power electronic converter, and each low-voltage digital battery system is composed of p digital battery strings in series or parallel.

[0026] A reconfigurable battery network controller is connected to the reconfigurable battery network, which is connected to the high-frequency power electronic switch array and is configured to manage the electronic switch state of the high-frequency power electronic switch array according to the state information of each digital energy storage subsystem.

[0027] A decentralized coordination controller is connected to each digital energy storage subsystem in the reconfigurable battery network.

[0028] The scale integration system comprises a battery operation system, a hardware control system and a digital battery, the hardware control system comprises a central processor and the reconfigurable battery network, and further comprises the reconfigurable battery network controller connected with the central processor, the global energy controller, each of the distributed coordination controllers, a digital battery system discharging circuit and a digital battery system charging circuit, the digital battery system charging circuit is connected with each of the digital battery systems in the reconfigurable battery network and an input side, and the digital battery system discharging circuit is connected with each of the digital battery systems in the reconfigurable battery network and an output side; the message interfaces of the global energy controller, each of the distributed coordination controllers and each of the digital energy storage subsystems are connected to a system message bus; the central processor is embedded with the battery operation system, and the battery operation system supports an open API.

[0029] Preferably, the control strategy of the reconfigurable battery network controller for the common DC bus of each of the digital energy storage subsystems is a centralized voltage stabilization control strategy, the control system of the centralized voltage stabilization strategy comprises a voltage outer loop and a current inner loop, wherein the control output of the voltage outer loop is the command current of the current inner loop, and the current inner loop has feedforward control and decoupling control to accelerate the dynamic response of the system.

[0030] The signals in the system message bus are time division multiplexing signals, the global energy controller and the distributed coordination controllers control the real-time output of each of the digital energy storage subsystems through a rolling horizon control strategy, each of the digital energy storage subsystems independently regulates the output of each of the low-voltage digital battery systems inside to form an autonomous distributed control structure.

[0031] The digital energy storage subsystem adopts a distributed energy on-demand control strategy for each of the low-voltage digital battery systems inside, the energy on-demand control strategy comprises a constant voltage mode, a constant current mode and a constant power mode, and the low-voltage digital battery system adopts a charging and discharging voltage active adjustment and parameter adaptive control strategy for each of the digital batteries inside.

[0032] Preferably, the state equation of the scale integration system is described as follows:

[0033]

[0034] wherein, x i (k) is the state variable of the i-th digital energy storage subsystem at the k-th moment, the matrix A and the matrix B are matrix parameters, u i (k) is the control input variable of the i-th digital energy storage subsystem at the k-th moment, and the u i (k) is the real-time output requirement of the system at the k+1-th moment of the global energy controller Actual output of subsystem at time k {Y 1,k Actual output of subsystem at time k {Y 2,k Actual output of subsystem at time k {Y m,k Actual output of subsystem at time k {Y Calculated.

[0035] According to the technical scheme, the small-capacity digital battery energy storage system large-scale integration method and system provided by the embodiment of the application, the large-scale integration system is composed of a battery operation system, a hardware control system and a digital battery, wherein: the hardware control system comprises a central processor and a reconfigurable battery network, further comprises a reconfigurable battery network controller, a global energy controller, a decentralized coordination controller, a digital battery system discharge circuit and a digital battery system charging circuit connected with the central processor, the digital battery system charging circuit is connected with each digital battery system in the reconfigurable battery network and an input side, the digital battery system discharge circuit is connected with each digital battery system in the reconfigurable battery network and an output side, and the reconfigurable battery network is controlled by the reconfigurable battery network controller and the global energy controller; the reconfigurable battery network is composed of a plurality of digital energy storage subsystems, the digital energy storage subsystem is composed of a low-voltage digital energy storage system, and the low-voltage digital energy storage system is composed of battery monomers in series or parallel connection. The application improves the control strategy of the large-scale energy storage system for the battery monomers, adopts the self-regulation and collaborative control combining the centralized control and the distributed control, the system only adopts the centralized control strategy for each digital energy storage subsystem in the reconfigurable battery network, the digital energy storage subsystem independently regulates and controls the output, adopts the distributed control strategy of the active modulation of the charging and discharging voltage and the parameter adaptive control for each low-voltage digital energy storage system in the subsystem, reduces the granularity of the battery control of the large-scale integration system, and improves the response speed and the control precision of the system. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a large-scale integration system architecture diagram of the small-capacity digital battery energy storage system.

[0037] Figure 2 It is a digital energy storage subsystem architecture diagram composed of a low-voltage digital energy storage system.

[0038] Figure 3 It is a connection diagram of the reconfigurable battery network controller and the reconfigurable battery network.

[0039] Figure 4 It is a schematic diagram of the global output control and the self-regulation control of each subsystem.

[0040] Figure 5 It is a bottom layer control mode diagram of the digital energy storage subsystem.

[0041] Figure 6 It is a common DC bus voltage stability control block diagram.

[0042] Figure 7 This is a schematic diagram of a balanced control strategy for a large-scale integrated system. Detailed Implementation

[0043] The technical solution and effects of the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] This invention provides a scalable integration system for a small-capacity digital battery energy storage system. It adopts a plug-and-play hierarchical control architecture for the low-voltage digital battery system. The scalable integration units of the small-capacity digital battery, from smallest to largest, are: digital battery, low-voltage digital battery system, digital energy storage subsystem, and reconfigurable battery network. Specifically, as follows... Figure 1 As shown, the reconfigurable battery network consists of m digital energy storage subsystems coupled with a high-frequency power electronic switch array, such as... Figure 2 As shown, the digital energy storage subsystem is formed by flexibly connecting and aggregating n small-capacity low-voltage digital battery systems through a power electronic converter. Further, the low-voltage digital battery system is composed of p digital batteries connected in series or parallel. This invention also includes a construction scheme for a large-scale integrated system, a communication architecture scheme for the electrochemical energy storage system, a software and hardware system integration scheme, and a voltage regulation and control method for the electrochemical energy storage system.

[0045] like Figure 1 As shown, the large-scale integrated system of small-capacity digital battery energy storage system (hereinafter referred to as the large-scale integrated system) provided by the present invention includes: a software operating system, a hardware control system, and a digital battery, wherein:

[0046] The hardware control system includes a central processing unit and a reconfigurable battery network, as well as a reconfigurable battery network controller, a global energy controller, a distributed coordination controller, a digital battery system discharge circuit, and a digital battery system charging circuit connected to the central processing unit. The reconfigurable battery network is controlled by the reconfigurable battery network controller and the global energy controller. A distributed and centralized control method is adopted for the state variables and control variables of each digital energy storage subsystem in the reconfigurable battery network. That is, energy on demand control is performed on each level of low-voltage digital battery system in the digital energy storage subsystem, and voltage stabilization control is performed on the common DC bus of each level of digital energy storage subsystem.

[0047] The software operating system, also known as the battery operating system, is crucial for supporting the overall system operation. Its software programs are embedded in the central processing unit, achieving seamless integration with the system hardware. Furthermore, the battery OS supports an open API (Application Programming Interface), allowing users to customize battery charging and discharging strategies according to their needs.

[0048] In the application, the reconfigurable battery network is coupled by m digital energy storage subsystems and a high-frequency power electronic switch array, a reconfigurable battery network controller manages the electronic switch state of the high-frequency power electronic switch array according to the state information of each digital energy storage subsystem, and each high-frequency power electronic switch in the high-frequency power electronic switch array is located at a node between a system DC bus and a common DC bus of each digital energy storage subsystem. Figure 3 As shown in the figure, the reconfigurable battery network controller is composed of m subsystem switching control units, each of the m subsystem switching control units is connected with one high-frequency power electronic switch and communicates with the internal CAN bus of the reconfigurable battery network controller; an embedded sensing device is built in the digital energy storage subsystem, the embedded sensing device is connected with a digital energy control chip of the subsystem switching control unit, for example, the sensor types in the embedded sensing device at least include a subsystem voltage collector and a temperature sensor, and the collected data forms voltage sampling data and temperature sampling data;

[0049] The digital energy control chip calculates the state information of the digital energy storage subsystem according to the sampling data of the embedded sensing device, and controls the switching state of the high-frequency power electronic switch according to the state information of the digital energy storage subsystem, so as to control the switching state of the digital energy storage subsystem in the reconfigurable battery network, wherein the state information of the digital energy storage subsystem includes a battery state of charge SOC (State Of Charge) and a battery state of health SOH (State Of Health), the battery state of charge SOC is calculated according to the voltage sampling data of the subsystem voltage collector, and the battery state of health SOH is calculated according to the temperature sampling data of the subsystem voltage collector.

[0050] The charging and discharging of the large-scale energy storage system are designed based on stable DC voltage, and the out-of-range DC voltage fluctuation will cause the risk of system instability, therefore, the centralized integrated system controls the common DC bus of each digital energy storage subsystem to be stable, as shown in the figure, Figure 6 The control system of the centralized voltage stabilization strategy is composed of a voltage outer loop and a current inner loop, wherein the control output of the voltage outer loop is the command current of the current inner loop, the current inner loop has feedforward control and decoupling control, and is used to accelerate the dynamic response of the system, the DC voltage controller controls the active current component through decomposition, Id(s) and Iq(s), and then converts into a discrete time domain control method to realize the control of the control object. Figure 6 According to the load characteristic matching requirement, different digital energy storage subsystems are selected by time division multiplexing to output in series in turn, and combined with Figure 2 The voltage fine adjustment unit (connected to the digital energy control chip) in the figure is used to realize the fine adjustment of the output voltage of the digital energy storage subsystem, so as to realize the purpose of the software-defined digital energy storage subsystem DC voltage output port.

[0051] The system's output control strategy for each digital energy storage subsystem is as follows: Under the autonomous distributed control structure, the energy flow fragmentation and reorganization of different individual cells / modules of batteries are realized: Each digital energy storage subsystem is connected to a distributed coordination controller. The message interfaces of the global energy controller, each distributed coordination controller, and each digital energy storage subsystem are all connected to the system message bus. The signal form in the system message bus is a time-division multiplexed signal. The global energy controller and the distributed coordination controller control the real-time output of each digital energy storage subsystem and the overall global output of the system through a rolling time-domain control strategy. The distributed coordination controller calculates the control input of each digital energy storage subsystem at the next moment. The digital energy storage subsystem independently regulates the output of each low-voltage digital battery system inside, forming an autonomous distributed control structure.

[0052] Specifically, such as Figure 4 As shown, the global energy controller sends the system's real-time output requirement at time k+1 to the system message bus. The i-th distributed coordinating controller obtains the actual output {Y} of all digital energy storage subsystems at time k via the system message bus. 1,k ,Y 2,k ,...,Y m,k}、 Under the current global output control mode of the large-scale integrated system, according to {Y 1,k ,Y 2,k ,...,Y m,k}、 Actual system output at time k Calculate the control input variable u of the i-th digital energy storage subsystem at time k+1. i (k+1), where, The control input variable u at time k+1 i (k+1) is input to the i-th digital energy storage subsystem; the i-th digital energy storage subsystem is based on u i (k+1) Independently control the output of each low-voltage digital battery system in the i-th digital energy storage subsystem, and at time k+1, change the actual output Y of the subsystem at time k+1. i,k+1 Send to the system message bus.

[0053] The state equation of a scalable integrated system can be described as follows:

[0054]

[0055] Where, x i(k) is the state variable of the k moment controlled by the i digital energy storage subsystem, and the matrix A and the matrix B are matrix parameters. According to the electrical and communication structure of the large-scale integrated system, a correlation control model of each digital energy storage subsystem is established, and on this basis, a global control model of the overall system is established, and the influence of the working state, control performance, system communication delay and other factors of the energy storage subsystem on the global response speed and control accuracy of the overall system is analyzed.

[0056] As shown in Figure 7 The global output control mode includes an external electrical system transient response mode, an external electrical system real-time scheduling mode and a digital energy storage system energy management mode. Through the respective mode models constructed by the software operating system, the present application aims to establish a group target consistency control strategy of the energy storage subsystem with the highest overall output accuracy of the system as the target. In order to ensure the available capacity of the digital energy storage system, the present application aims to establish a balanced control strategy of the SOC of each digital energy storage subsystem with the maximum overall available capacity of the digital energy storage system as the target.

[0057] For the global output control strategy of the overall system, the present application aims to establish a corresponding global control strategy for the external electrical system transient response mode, the real-time scheduling mode and the local energy management mode. For the external electrical system transient response mode and the real-time scheduling mode, the key point of the global control strategy of the overall system lies in the accurate estimation of the control range and response ability, and the fast control of the system. According to the state of each energy storage subsystem, the present application aims to use the least square support vector machine method to perform real-time estimation on the feasible region of the system, including the available charging and discharging power, the electric quantity and the climbing rate of the system. The fast control strategy of the overall system is based on the model predictive control technology, and comprehensively considers the dynamic performance, control target and constraint condition of the large-scale digital energy storage system, establishes an online optimization heuristic control method, uses the rolling time domain control strategy to realize real-time control, and improves the global control speed of the overall system. In the large-scale digital energy storage local energy management mode, the present application aims to establish a global optimization energy management strategy of the system with economy and system life as the target.

[0058] Based on the centralized control of the large-scale integrated system on each digital energy storage subsystem, the digital energy storage subsystem adopts a distributed energy on-demand control strategy on each level of the internal low-voltage digital battery system. Figure 2 As shown in the figure, the digital energy storage subsystem is flexibly connected and aggregated by n small-capacity low-voltage digital battery systems through power electronic converters, and through active adjustment of the charging and discharging voltage and adaptive control of the parameters, the stability margin of the low-voltage digital battery system is expanded, and then a large-scale grid battery module is formed. The low-voltage digital battery system is composed of p digital batteries in series or parallel connection, and the low-voltage digital battery system adopts an active adjustment of the charging and discharging voltage and an adaptive control strategy of the parameters on each digital battery. The energy on-demand control strategy of the digital energy storage subsystem includes a constant voltage mode, a constant current mode and a constant power mode, and can realize free switching of charging and discharging.Figure 5 As shown, by switching, each low-voltage digital battery system in the digital energy storage subsystem is in constant voltage mode, constant current mode, and constant power mode, and the low-voltage digital battery system can charge and discharge in the three modes. Each digital battery system is powered by a digital battery system charging circuit and discharged by a digital battery system discharging circuit, and the charging and discharging circuits meet the requirements of low power consumption, high reliability, high safety, and low complexity.

[0059] The application also provides a small-capacity digital battery energy storage system large-scale integration method. First, single batteries are connected in the form of a reconfigurable battery network, then each digital energy storage subsystem is connected to a reconfigurable battery network controller, a distributed coordination controller is connected for each digital energy storage subsystem in the reconfigurable battery network, and finally a large-scale integration system is constructed according to the structure shown. Figure 1 The system discharging circuit is connected to the reconfigurable battery network and the output side; the global energy controller, each distributed coordination controller, and the message interface of each digital energy storage subsystem are connected to the system message bus; a battery operating system is embedded in the central processor, and the battery operating system supports an open API. The battery operating system is used to construct a control model for the large-scale integration system, each digital energy storage subsystem, and the low-voltage digital battery system,

[0060] The application improves the control strategy of the large-scale energy storage system for the battery monomer, adopts a combination of centralized and distributed self-regulation collaborative control, the system only adopts a centralized control strategy for each digital energy storage subsystem in the reconfigurable battery network, the digital energy storage subsystem independently regulates and controls its output, adopts a distributed control strategy of charging and discharging voltage active modulation and parameter adaptive control for each low-voltage digital energy storage system in the subsystem, reduces the granularity of battery control of the large-scale integration system, and improves the system response speed and control accuracy. The digital energy storage subsystem can be plug and play without affecting the global output, has good configuration flexibility and scalability, and the application can effectively improve the working efficiency, reliability, and safety of the large-scale energy storage system.

[0061] The above only discloses preferred embodiments of the application, and of course cannot limit the scope of the application, and those skilled in the art can understand that all or part of the above-mentioned embodiments can be implemented, and equivalent changes made according to the claims of the application still belong to the scope covered by the application.

Claims

1. A large-scale integrated system for small-capacity digital battery energy storage, characterized in that, The large-scale integrated system includes: a battery operating system, a hardware control system, and a digital battery, wherein: The hardware control system includes a central processing unit and a reconfigurable battery network, and further includes a reconfigurable battery network controller, a global energy controller, a distributed coordination controller, a digital battery system discharge circuit, and a digital battery system charging circuit connected to the central processing unit. The digital battery system charging circuit is connected to each digital battery system in the reconfigurable battery network and its input side. The digital battery system discharge circuit is connected to each digital battery system in the reconfigurable battery network and its output side. The reconfigurable battery network is controlled by the reconfigurable battery network controller and the global energy controller. The battery operating system is embedded in the central processing unit, and the battery operating system supports open APIs. The reconfigurable battery network is composed of m digital energy storage subsystems coupled with a high-frequency power electronic switch array. The reconfigurable battery network controller manages the electronic switch status of the high-frequency power electronic switch array according to the status information of each of the digital energy storage subsystems. Each high-frequency power electronic switch in the high-frequency power electronic switch array is located at a node between the system DC bus and the common DC bus of each of the digital energy storage subsystems. Each of the digital energy storage subsystems is connected to a distributed coordination controller. The message interfaces of the global energy controller, each of the distributed coordination controllers, and each of the digital energy storage subsystems are all connected to the system message bus. The signal form in the system message bus is a time-division multiplexed signal. The global energy controller and the distributed coordination controller control the real-time output of each of the digital energy storage subsystems through a rolling time-domain control strategy. Each digital energy storage subsystem independently regulates the output of each low-voltage digital battery system within it, forming a self-regulating distributed control structure. The digital energy storage subsystem is formed by flexibly connecting and aggregating n small-capacity low-voltage digital battery systems through power electronic converters. The digital energy storage subsystem adopts a distributed energy-on-demand control strategy for each level of the internal low-voltage digital battery system. The low-voltage digital battery system is composed of p digital batteries connected in series or in parallel. The low-voltage digital battery system adopts an active adjustment of charging and discharging voltage and parameter adaptive control strategy for each internal digital battery.

2. The large-scale integrated system of small-capacity digital battery energy storage system as described in claim 1, characterized in that, The reconfigurable battery network controller consists of m subsystem switching control units, each of which is connected to a high-frequency power electronic switch and communicates with the internal CAN bus of the reconfigurable battery network controller. The digital energy storage subsystem has a built-in embedded sensing device, which is connected to the digital energy control chip of the subsystem switching control unit. The sensor types in the embedded sensing device include at least a subsystem voltage acquisition device and a temperature sensor. The digital energy control chip calculates the state information of the digital energy storage subsystem based on the sampling data of the embedded sensing device, and controls the switching state of the high-frequency power electronic switch based on the state information of the digital energy storage subsystem to control the switching state of the digital energy storage subsystem. The state information of the digital energy storage subsystem includes the battery state of charge (SOC) and the battery state of health (SOH). The battery state of charge (SOC) is calculated based on the voltage sampling data of the subsystem voltage collector, and the battery state of health (SOH) is calculated based on the temperature sampling data of the subsystem voltage collector.

3. The large-scale integrated system of small-capacity digital battery energy storage system as described in claim 2, characterized in that, The control strategy of the reconfigurable battery network controller for the common DC bus of each digital energy storage subsystem is a centralized voltage regulation control strategy. The control system of the centralized voltage regulation control strategy consists of an outer voltage loop and an inner current loop. The control output of the outer voltage loop is the command current of the inner current loop. The inner current loop has feedforward control and decoupling control to accelerate the dynamic response of the system.

4. The large-scale integrated system of small-capacity digital battery energy storage system as described in claim 3, characterized in that, The energy-on-demand control strategy of the digital energy storage subsystem includes constant pressure mode, constant current mode, and constant power mode.

5. The scalable integration system of a small-capacity digital battery energy storage system as described in claim 4, characterized in that, The global energy controller, controlled by the central processing unit, is used to send the system's real-time output requirement at time k+1 to the system message bus. ; The i-th distributed coordination controller obtains the actual output {Y} of all the digital energy storage subsystems at time k through the system message bus. 1,k ,Y 2,k ,...,Y m,k }, the aforementioned In the current global output control mode of the large-scale integrated system, according to {Y 1,k ,Y 2,k ,...,Y m,k }, the aforementioned Actual system output at time k Calculate the control input variable u of the i-th digital energy storage subsystem at time k+1. i (k+1), where, The control input variable u at time k+1 i (k+1) is input to the i-th digital energy storage subsystem; The i-th digital energy storage subsystem is used to, according to the u i (k+1) Independently control the output of each low-voltage digital battery system in the i-th digital energy storage subsystem, and at time k+1, change the actual output Y of the subsystem at time k+1. i,k+1 Send to the system message bus.

6. The scalable integration system of a small-capacity digital battery energy storage system as described in claim 5, characterized in that, The global output control modes include external electrical system transient response mode, external electrical system real-time scheduling mode, and digital energy storage system energy management mode.

7. The scalable integration system of a small-capacity digital battery energy storage system as described in claim 6, characterized in that, The state equation of the large-scale integrated system is described as follows: ； in, Let A and B be the state variables at time k controlled by the i-th digital energy storage subsystem, and matrices A and B are both matrix parameters.

8. A method for large-scale integration of a small-capacity digital battery energy storage system, characterized in that, include: A reconfigurable battery network is constructed, which consists of m digital energy storage subsystems coupled with a high-frequency power electronic switch array. Each high-frequency power electronic switch in the high-frequency power electronic switch array is located at a node between the system DC bus and the common DC bus of each digital energy storage subsystem. Each digital energy storage subsystem is formed by n small-capacity low-voltage digital battery systems flexibly connected and aggregated through a power electronic converter. Each low-voltage digital battery system is composed of p digital batteries connected in series or in parallel. A reconfigurable battery network controller is connected to the reconfigurable battery network, and the reconfigurable battery network controller is connected to the high-frequency power electronic switch array and is used to manage the electronic switch state of the high-frequency power electronic switch array according to the state information of each of the digital energy storage subsystems; Connect a distributed coordination controller to each of the digital energy storage subsystems in the reconfigurable battery network; A large-scale integrated system is constructed, comprising a battery operating system, a hardware control system, and digital batteries. The hardware control system includes a central processing unit (CPU) and the reconfigurable battery network, and further includes a reconfigurable battery network controller, a global energy controller, each of the distributed coordination controllers, a digital battery system discharge circuit, and a digital battery system charging circuit connected to the CPU. The digital battery system charging circuit is connected to each digital battery system in the reconfigurable battery network and its input side, and the digital battery system discharge circuit is connected to each digital battery system in the reconfigurable battery network and its output side. The message interfaces of the global energy controller, each of the distributed coordination controllers, and each of the digital energy storage subsystems are all connected to the system message bus. The system message bus uses time-division multiplexed signals. The global energy controller and the distributed coordination controller control the real-time output of each digital energy storage subsystem through a rolling time-domain control strategy. Each digital energy storage subsystem independently regulates the output of its internal low-voltage digital battery systems, forming a self-regulating distributed control structure. The digital energy storage subsystem adopts a distributed energy-on-demand control strategy for each level of its internal low-voltage digital battery systems. The low-voltage digital battery systems employ active adjustment of charging and discharging voltage and adaptive parameter control strategies for each internal digital battery. The central processing unit embeds the battery operating system, which supports open APIs.

9. The method for large-scale integration of a small-capacity digital battery energy storage system as described in claim 8, characterized in that, The control strategy of the reconfigurable battery network controller for the common DC bus of each digital energy storage subsystem is a centralized voltage regulation control strategy. The control system of the centralized voltage regulation control strategy consists of a voltage outer loop and a current inner loop. The control output of the voltage outer loop is the command current of the current inner loop. The current inner loop has feedforward control and decoupling control to accelerate the dynamic response of the system. The energy-on-demand control strategy includes constant voltage mode, constant current mode, and constant power mode.

10. The method for large-scale integration of a small-capacity digital battery energy storage system as described in claim 9, characterized in that, The state equation of the large-scale integrated system is described as follows: ； in, Let u be the state variable at time k of the control of the i-th digital energy storage subsystem. Matrix A and matrix B are both matrix parameters. i (k) is the control input variable of the i-th digital energy storage subsystem at time k, where u i (k) is based on the real-time output requirement of the system at time k+1 of the global energy controller. Actual output of subsystem at time k {Y} 1,k ,Y 2,k ,...,Y m,k Actual system output at time k Calculated.

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