Method, system, electronic device and storage medium for controlling a hybrid energy storage system

Abstract

The application provides a control method and system of a hybrid energy storage system, an electronic device and a storage medium. The method comprises: acquiring power grid operation states collected by a first energy storage converter and a second energy storage converter, and battery operation states of connected energy storage systems; calculating total power demand information based on the power grid operation states and power grid scheduling instructions; performing power distribution based on the total power demand information to obtain target power distribution results of the power-type energy storage system and the energy-type energy storage system respectively; and controlling the first energy storage converter and the second energy storage converter to instruct the connected energy storage systems to perform charging operation or discharging operation through respective corresponding grid-forming control algorithms based on the target power distribution results of the connected energy storage systems. In this way, quick power support can be provided when the power grid frequency is disturbed, the operation efficiency of the hybrid energy storage system is improved, and the service life of each type of energy storage system is prolonged.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, specifically to a control method, system, electronic device, and storage medium for a hybrid energy storage system. Background Technology

[0002] As the proportion of new energy power generation in power electronic systems continues to increase, the demand for rapid power regulation and stable support capabilities in the entire power system is also showing a continuous upward trend. Consequently, grid-based hybrid energy storage systems, which actively construct voltage and frequency benchmarks using power electronic systems, are gradually becoming an indispensable key component of new power systems. However, when scheduling and using various types of energy storage systems, most hybrid energy storage systems adopt relatively simple parallel or time-sharing activation strategies, which are difficult to adapt to various operating conditions, thus affecting the operating efficiency and lifespan of the energy storage systems. Summary of the Invention

[0003] The embodiments of this application provide a control method, system, electronic device, and storage medium for a hybrid energy storage system, which can provide rapid power support when the grid frequency is disturbed, suppress rapid changes in the grid frequency, and help extend the life of various types of energy storage systems.

[0004] In a first aspect, embodiments of this application provide a control method for a hybrid energy storage system, the hybrid energy storage system comprising a power-type energy storage system and an energy-type energy storage system, wherein the power-type energy storage system is connected to the power grid via a first energy storage converter, and the energy-type energy storage system is connected to the power grid via a second energy storage converter, the method comprising: Acquire the grid operating status and the battery operating status of the connected energy storage system collected by the first energy storage converter and the second energy storage converter; Based on the power grid operating status and power grid dispatch instructions, calculate the total power demand information; Based on the total power demand information, power allocation is performed to obtain the target power allocation results for the power-type energy storage system and the energy-type energy storage system, respectively. The first energy storage converter and the second energy storage converter control each other to instruct the connected energy storage system to perform charging or discharging operations based on the target power allocation result of the connected energy storage system through their respective network control algorithms.

[0005] In some embodiments, the battery operating state includes at least one of the energy storage system's state of charge and the allocable power range; The process of allocating power based on the total power demand information to obtain the target power allocation results for the power-type energy storage system and the energy-type energy storage system respectively includes: Based on the total power demand information, power allocation is performed to obtain the power allocation results for the power-type energy storage system and the energy-type energy storage system, respectively. Based on the battery operating status of each of the energy storage systems, the specified power allocation results are corrected to obtain the target power allocation results corresponding to the power-type energy storage system and the energy-type energy storage system, respectively.

[0006] In some embodiments, the step of allocating power based on the total power demand information to obtain the power allocation results corresponding to the power-type energy storage system and the energy-type energy storage system respectively includes: The target frequency division point is determined based on the battery operating status of the power-type energy storage system and / or the energy-type energy storage system. Based on the target frequency division point, the total power demand information is decomposed in the frequency domain to obtain high-frequency power components and low-frequency power components. The high-frequency power component is used as the power allocation result corresponding to the power-type energy storage system, and the low-frequency power component is used as the power allocation result corresponding to the energy-type energy storage system.

[0007] In some embodiments, determining the target frequency division point based on the battery operating state of the power-type energy storage system and / or the energy-type energy storage system includes: When the state of charge of the power-type energy storage system is outside the corresponding preset state of charge range, the initial frequency division point is increased to obtain the target frequency division point.

[0008] In some embodiments, the step of correcting the specified power allocation result based on the battery operating state of each of the energy storage systems to obtain the target power allocation result corresponding to each of the power-type energy storage system and the energy-type energy storage system includes: Determine the relationship between the state of charge (SOC) of the power-type energy storage system and the preset SOC range. When the state of charge of the power-type energy storage system is outside the corresponding preset state of charge range, the power allocation result corresponding to the power-type energy storage system is reduced, and the power allocation result corresponding to the energy-type energy storage system is increased, so as to obtain the target power allocation result corresponding to the power-type energy storage system and the energy-type energy storage system respectively.

[0009] In some embodiments, the method further includes: If the target power allocation result for one type of energy storage system is not within the corresponding allocable power range, the target power allocation result for that type of energy storage system is adjusted, and the target power allocation result for another type of energy storage system is adjusted according to the adjusted power value; or, If the target power allocation results for both the power-type energy storage system and the energy-type energy storage system are not within the corresponding allocable power range, the target power allocation results for both the power-type energy storage system and the energy-type energy storage system shall be adjusted. To obtain new target power allocation results corresponding to the power-type energy storage system and / or the energy-type energy storage system.

[0010] In some embodiments, the control parameters of the grid control algorithms corresponding to the first energy storage converter and the second energy storage converter are determined based on the grid operating status and the battery operating status of the connected energy storage system, respectively. The control parameters include at least one of the virtual inertia coefficient, droop coefficient, and damping coefficient.

[0011] In some embodiments, the energy-type energy storage system includes a lithium battery energy storage system, and the power-type energy storage system includes a sodium battery energy storage system.

[0012] Secondly, embodiments of this application provide a hybrid energy storage system, which includes an energy management system, a power-type energy storage system, and an energy-type energy storage system. The power-type energy storage system is connected to the power grid via a first energy storage converter, and the energy-type energy storage system is connected to the power grid via a second energy storage converter. The energy management system is communicatively connected to both the first and second energy storage converters. The energy management system is configured as follows: Acquire the grid operating status and the battery operating status of the connected energy storage system collected by the first energy storage converter and the second energy storage converter; Based on the power grid operating status and power grid dispatch instructions, calculate the total power demand information; Based on the total power demand information, power allocation is performed to obtain the target power allocation results for the power-type energy storage system and the energy-type energy storage system, respectively. The first energy storage converter and the second energy storage converter control each other to instruct the connected energy storage system to perform charging or discharging operations based on the target power allocation result of the connected energy storage system through their respective network control algorithms.

[0013] Thirdly, embodiments of this application provide an electronic device, the electronic device comprising: One or more processors; Memory; and One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by the processor to implement the control method of the hybrid energy storage system provided in any of the embodiments of this application.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium having a computer program stored thereon, the computer program being loaded by a processor to execute the control method for a hybrid energy storage system as described in any one of the embodiments of this application.

[0015] The beneficial effects of the embodiments of this application are as follows: In the embodiments of this application, by collecting the grid operating status and the battery status of various types of energy storage systems, and combining the total power demand information with grid dispatch instructions, power allocation is performed according to the different characteristics of power-type and energy-type energy storage systems to obtain the target allocation results for various types of energy storage systems. Finally, the first energy storage converter and the second energy storage converter respectively execute the target power allocation results using their respective corresponding grid control algorithms. This can provide rapid power support when grid frequency disturbances occur, suppress rapid changes in grid frequency, and help extend the lifespan of various types of energy storage systems. Compared with energy-type energy storage systems or traditional follower-type energy storage systems, it can participate in frequency stabilization control in the early stages of grid disturbances, thereby improving the operating efficiency of hybrid energy storage systems and enhancing their frequency support capabilities under weak grid and islanded grid operating conditions. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is an application scenario diagram of the control method for the hybrid energy storage system provided in the embodiments of this application; Figure 2 This is an exemplary flowchart of a control method for a hybrid energy storage system provided in an embodiment of this application; Figure 3 This is an exemplary schematic diagram of a hybrid energy storage system provided in an embodiment of this application; Figure 4 This is an exemplary schematic diagram of the control device for a hybrid energy storage system provided in an embodiment of this application; Figure 5 This is an exemplary schematic diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. At the same time, in the description of the embodiments of this application, the terms "first," "second," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0019] Hybrid Energy Storage System (HESS) combines power storage devices (such as supercapacitors and flywheel energy storage) with energy storage devices (such as lithium-ion batteries and flow batteries). It can take advantage of the former's fast response speed and long cycle life and the latter's high energy density and strong continuous discharge capability to effectively smooth the power fluctuations of renewable energy generation and improve the power quality and operational stability of the power grid.

[0020] Currently, the scheduling and control of different types of energy storage subsystems in related hybrid energy storage systems usually adopt simple parallel operation or time-sharing switching strategies. They lack the adaptive coordination capability based on grid operating conditions and the energy storage's own state, making it difficult to cope with changing operating scenarios. This results in low overall regulation efficiency of hybrid energy storage systems, insufficient dynamic response performance and equipment utilization, which in turn affects the overall regulation performance and the lifespan of the energy storage system.

[0021] In view of this, this application proposes a control method for a hybrid energy storage system. By integrating grid operating status and grid dispatch commands to calculate total power demand information, power is allocated between the power-type and energy-type energy storage systems. The initial power allocation result is then corrected based on the respective battery operating states, preventing the energy storage system from operating beyond its battery capacity and improving safety and lifespan. The first and second energy storage converters execute the target power allocation result using their respective grid control algorithms, actively providing inertia and damping support to enhance grid stability. The power-type and energy-type energy storage systems operate collaboratively, responding to high-frequency power fluctuations and continuous energy throughput respectively, achieving complementary advantages and ensuring long-term energy support while meeting dynamic dispatch commands. Simultaneously, through reasonable power allocation (allowing the power-type energy storage system to handle high-frequency, high-rate power fluctuations, while the energy-type energy storage system handles relatively stable, low-rate energy throughput) and real-time correction based on battery operating states, excessively high-rate charge / discharge commands are avoided for the energy-type energy storage system, thereby extending its actual usable lifespan.

[0022] Figure 1 This is an application scenario diagram of the control method for a hybrid energy storage system provided in the embodiments of this application.

[0023] The control method for hybrid energy storage systems provided in this application can be applied to various hybrid energy storage systems. For example, a hybrid energy storage system composed of a supercapacitor battery system and a lithium battery system, or a hybrid energy storage system composed of a power-type energy storage system (such as a sodium-ion battery system) and an energy-type energy storage system (such as a lithium-ion battery system).

[0024] The implementing entity of the technical solution in this application embodiment can be an electronic device, which can be executed by the control device of the hybrid energy storage system. The control device of the hybrid energy storage system can be implemented in hardware and / or software, and can be configured in any electronic device with network communication capabilities. The electronic device can also be a server, a terminal, or other similar device.

[0025] The server can be a standalone physical server, a server cluster or distributed system composed of multiple physical servers, or a cloud server providing basic cloud computing services such as cloud services, cloud databases, and cloud computing. The terminal can include, but is not limited to, mobile phones, computers, and smart voice interaction devices. The terminal and server can be directly or indirectly connected via wired or wireless communication methods; this embodiment does not impose any limitations on this.

[0026] In some embodiments, the application scenario may also include, for example, networks, storage devices, etc. Networks may include any suitable wired or wireless networks that facilitate the exchange of information and / or data. Storage devices are used to store data, instructions, and / or any other information.

[0027] Please see Figure 1 , Figure 1 This is a schematic diagram illustrating a scenario of an operation control system for a hybrid energy storage system provided in an embodiment of this application. The system may include at least one terminal, at least one server, at least one database, and a network. A user-held terminal can connect to different servers via the network. The terminal is any device with computing hardware capable of supporting and executing software products corresponding to games. Furthermore, when the system includes multiple terminals, multiple servers, and multiple networks, different terminals can connect to each other through different networks and different servers. The network can be a wireless network or a wired network, such as a wireless local area network (WLAN), local area network (LAN), cellular network, 2G network, 3G network, 4G network, 5G network, etc. Additionally, different terminals can also connect to other terminals or to servers using their own Bluetooth networks or hotspot networks.

[0028] It is worth noting that the application scenarios of the control method for hybrid energy storage systems are provided for illustrative purposes only and are not intended to limit the scope of the embodiments of this application. Those skilled in the art can make various changes and modifications based on the description of the embodiments of this application. For example, the application scenarios may also include databases, information sources, etc. Furthermore, the application scenarios may be implemented on other devices to achieve similar or different functions. However, these changes and modifications will not depart from the scope of the embodiments of this application.

[0029] Figure 2 This is an exemplary flowchart of a control method for a hybrid energy storage system provided in an embodiment of this application. The hybrid energy storage system includes a power-type energy storage system and an energy-type energy storage system. The power-type energy storage system is connected to the grid via a first energy storage converter, and the energy-type energy storage system is connected to the grid via a second energy storage converter. In some embodiments, process 200 can be executed based on electronic devices. Figure 2 As shown, process 200 includes the following steps.

[0030] Step 210: Obtain the grid operation status and battery operation status of the connected energy storage system collected by the first energy storage converter and the second energy storage converter.

[0031] Power-type energy storage systems refer to energy storage systems that can quickly respond to power commands, have high power density and cycle life but relatively low energy density, such as supercapacitor energy storage systems, flywheel energy storage systems or sodium-ion battery energy storage systems.

[0032] Energy storage systems refer to energy storage forms with relatively high energy density, capable of continuous charging and discharging for a relatively long time, but with relatively slow response speed, such as lithium-ion battery energy storage systems, flow battery energy storage systems, or lead-carbon battery energy storage systems.

[0033] An energy storage converter is a power electronic device that connects an energy storage system to the power grid. It is used to control the charging or discharging power of the energy storage system according to the received power command, so as to realize AC to DC conversion and grid connection control.

[0034] The power grid operating status refers to parameters that characterize the working condition of the power grid. For example, the power grid operating status may include, but is not limited to, power grid frequency, frequency change rate, frequency deviation, voltage amplitude, and voltage fluctuation.

[0035] Battery operating status refers to parameters that characterize the working condition of an energy storage system. For example, battery operating status may include, but is not limited to, the state of charge, state of health, temperature, voltage, and charge / discharge power limits of the energy storage system.

[0036] Specifically, frequency deviation refers to the deviation between the current measured frequency of the power grid and its rated frequency (usually 50Hz or 60Hz). Voltage deviation refers to the deviation between the current measured effective voltage value of the power grid and its rated voltage. The rate of frequency change is used to reflect the severity of frequency fluctuations; for example, the rate of frequency change can be determined by the derivative of the power grid's frequency with respect to time.

[0037] In some embodiments, the energy management system is communicatively connected to a first energy storage converter and a second energy storage converter. The energy storage converter is used to detect the voltage and current at its AC side connection point with the power grid, and to calculate the current grid frequency, rate of frequency change, frequency deviation, and the magnitude and direction of active and reactive power as data of the grid operating status.

[0038] In some embodiments, the first energy storage converter is communicatively connected to the power energy storage system and, under certain circumstances (e.g., in real time, at intervals, or triggered under certain circumstances), actively acquires parameters such as the state of charge, temperature, and maximum allowable charge and discharge power of the power energy storage system as data on the battery operating status of the power energy storage system.

[0039] In some embodiments, the second energy storage converter is communicatively connected to the energy storage system and, under certain circumstances (e.g., in real time, at intervals, or triggered under certain circumstances), actively acquires parameters such as the state of charge, temperature, and maximum allowable charge / discharge power of the energy storage system as data on the battery operating status of the energy storage system.

[0040] It is worth noting that the acquired power grid operating status and battery operating status can include both real-time measured values ​​and estimated values ​​obtained by filtering or state estimation of the measured values. This application does not limit this.

[0041] Step 220: Calculate the total power demand information based on the power grid operating status and power grid dispatch instructions.

[0042] A grid dispatch command refers to a power command that requires the hybrid energy storage system to perform. For example, a grid dispatch command may include power command values ​​(such as active power command values ​​and reactive power command values). For instance, a positive power command value indicates that the hybrid energy storage system needs to discharge to the grid, while a negative value indicates that the hybrid energy storage system needs to charge from the grid.

[0043] In some embodiments, grid dispatch instructions may be generated by the grid dispatch center and sent to the energy management system.

[0044] Total power demand information refers to the power that a hybrid energy storage system should handle (e.g., the power it should supply to the grid or the power it should absorb from the grid). For example, total power demand information may include the active power it should handle and the reactive power it should handle.

[0045] In some embodiments, power demand information can be determined based on frequency deviation, frequency change rate, and grid dispatch instructions in the grid operating state. It is understood that the grid operating state can be the grid operating state collected by the first energy storage converter, or the grid operating state collected by the second energy storage converter, or determined based on the grid operating states collected by both the first and second energy storage converters.

[0046] It is understood that, depending on the actual application requirements, the response may be limited to active power demand information, reactive power demand information, or both. This application embodiment does not limit this.

[0047] In some embodiments, a model predictive control method is also employed, which uses the grid operating state as a feedback quantity and the grid dispatch command as a reference trajectory. By optimizing and solving the optimal power sequence, the first value in the optimal power sequence is used as the total power demand information at the current moment.

[0048] Step 230: Based on the total power demand information, power allocation is performed to obtain the target power allocation results for the power-type energy storage system and the energy-type energy storage system, respectively.

[0049] Power allocation refers to the process of allocating a portion of the power value represented by the total power demand information to a power-type energy storage system and another portion to an energy-type energy storage system, according to a preset allocation rule.

[0050] In some embodiments, different priorities can be pre-set for power-type energy storage systems and energy-type energy storage systems. When the absolute value of the total power demand information does not exceed a preset threshold (e.g., 80%) of the rated capacity of the power-type energy storage system, it is preferentially allocated to the power-type energy storage system to avoid frequent start-ups and shutdowns of the energy-type energy storage system. When the absolute value of the total power demand information exceeds the preset threshold of the rated capacity of the power-type energy storage system, the portion exceeding the rated capacity is allocated to the energy-type energy storage system. This can reduce the cycle number of the energy-type energy storage system and extend its service life.

[0051] In some embodiments, a planning method can be employed to minimize the overall operating cost of the hybrid energy storage system. This involves establishing charging and discharging loss models and aging cost models that include both power-type and energy-type energy storage. Total power demand information is used as a constraint, and a quadratic or linear programming problem is solved in real time to obtain the target power allocation result that minimizes the objective function. This target power allocation result can dynamically adjust the power proportion undertaken by each type of energy storage system based on the differences in real-time battery operating status and cost between the two types of energy storage systems.

[0052] Step 240: Control the first energy storage converter and the second energy storage converter to instruct the connected energy storage system to perform charging or discharging operations based on the target power allocation result of the connected energy storage system through their respective network control algorithms.

[0053] In some embodiments, the target power allocation result may include a first power value of the power-type energy storage system and a second power value of the energy-type energy storage system.

[0054] In some embodiments, a first power command can be generated based on a first power value and sent to a first energy storage converter, so that the first energy storage converter can control the power-type energy storage system to perform charging or discharging operations based on the first power command.

[0055] In some embodiments, a second power command can be generated based on a second power value and sent to a second energy storage converter, so that the second energy storage converter can control the energy storage system to perform charging or discharging operations based on the second power command.

[0056] In some embodiments, the network control algorithm may employ a virtual synchronous machine control algorithm, a droop control algorithm, and a virtual inertia control algorithm, or a combination thereof.

[0057] In some embodiments, the battery operating state includes at least one of the energy storage system's state of charge and the allocable power range; Power allocation is performed based on total power demand information to obtain the target power allocation results for power-type energy storage systems and energy-type energy storage systems, including: Power allocation is performed based on total power demand information to obtain the power allocation results for power-type energy storage systems and energy-type energy storage systems respectively. Based on the battery operating status of each energy storage system, the specified power allocation results are corrected to obtain the target power allocation results for each of the power-type energy storage system and the energy-type energy storage system.

[0058] Among these, the correction operation can be to reduce, increase, or redistribute the power values ​​that various energy storage systems should bear.

[0059] The specified power allocation result can be the initial power allocation result of a power-type energy storage system, and / or the initial power allocation result of an energy-type energy storage system, depending on the battery operating status of each energy storage system.

[0060] In some embodiments, the target power allocation result refers to the power value that needs to be undertaken by the power-type energy storage system and the energy-type energy storage system after correcting the initial power allocation result. The target power allocation result includes a first power value that the power-type energy storage system needs to actually perform (such as charging or discharging operations), and a second power value that the energy-type energy storage system needs to actually perform (such as charging or discharging operations).

[0061] In some embodiments, the maximum allowable power (also known as the current maximum allowable charge / discharge power) in the battery operating state of various energy storage system batteries can be obtained, and the power command value in the power allocation result can be compared with the corresponding maximum allowable power to correct the corresponding power allocation result.

[0062] In some embodiments, the state of charge (SOC) of the batteries in various energy storage systems can be obtained, and the power allocation result of the specified energy storage system can be corrected based on the SOC of the energy storage system.

[0063] In some embodiments, power allocation is performed based on total power demand information to obtain power allocation results for power-type energy storage systems and energy-type energy storage systems, including: Determine the target frequency division point based on the battery operating status of power-type energy storage systems and / or energy-type energy storage systems; Based on the target frequency division point, the total power demand information is decomposed in the frequency domain to obtain high-frequency power components and low-frequency power components. The high-frequency power component is used as the power allocation result for the power-type energy storage system, and the low-frequency power component is used as the power allocation result for the energy-type energy storage system.

[0064] In some embodiments, the power allocation result includes the active power allocation result.

[0065] In some embodiments, the total power demand information includes the total active power demand, which can be filtered. Specifically, a first-order or second-order low-pass digital filter is configured, with the cutoff frequency set according to the response capability of the power-type energy storage system, for example, a cutoff frequency of 0.1Hz. The P_total signal is input to the low-pass digital filter, which outputs a low-frequency power component P_low. This low-frequency power component P_low serves as the active power allocation result P_E of the energy-type energy storage system. Then, the low-frequency power component P_low is subtracted from the total active power demand P_total to obtain the high-frequency power component P_high, i.e., P_high = P_total - P_low. This high-frequency power component P_high serves as the active power allocation result P_P of the power-type energy storage system. Through this allocation method, the power-type energy storage system responds to rapidly changing power components, while the energy-type energy storage system handles slowly changing power components, fully utilizing its large-capacity energy storage characteristics.

[0066] The frequency division point is the boundary frequency that separates high-frequency power components from low-frequency power components, usually measured in Hz. When allocating power, frequency components above the frequency division point can be considered high-frequency power components. High-frequency power components are characterized by rapid changes and frequent fluctuations, making them suitable for power-type energy storage systems with fast response speeds and long cycle lives. Conversely, frequency components below the frequency division point can be considered low-frequency power components. Low-frequency power components are characterized by slow changes and longer durations, making them suitable for energy-type energy storage systems with high energy density and strong continuous charge-discharge capabilities.

[0067] In some embodiments, the target frequency division point can be determined based on prior knowledge or manual input.

[0068] In some embodiments, the target frequency division point may be the optimal frequency division point dynamically determined based on the current battery operating state of the power-type energy storage system and / or the energy-type energy storage system.

[0069] By incorporating battery operating status as the basis for determining the target frequency division point, the frequency division point can be adaptively adjusted, thereby making fuller use of the real-time availability of both types of energy storage systems. Specifically, the target frequency division point can be determined based on the battery operating status of the power-type energy storage system, the battery operating status of the energy-type energy storage system, or both. For example, when the battery operating status of one energy storage system approaches its safety boundary, the frequency division point can be appropriately adjusted to transfer part of the power component that should have been handled by that energy storage system to another energy storage system, in order to avoid overcharging, over-discharging, or power saturation.

[0070] In some embodiments, determining the target frequency division point based on the battery operating state of the power-type energy storage system and / or the energy-type energy storage system includes: When the state of charge of a power-type energy storage system is outside the corresponding preset state of charge range, the initial frequency division point is increased to obtain the target frequency division point.

[0071] The initial frequency division point can be a pre-set frequency division point. For example, the initial frequency division point can be the default frequency division point when the hybrid energy storage system is turned on, or the frequency division point of the last response to the grid dispatch command, etc., but this application embodiment does not limit this.

[0072] State of charge (SBC) represents the percentage of a storage system's current remaining energy capacity relative to its rated capacity, ranging from 0% to 100%. A high SBC reflects the system's available charging and discharging capabilities: a high SBC indicates sufficient discharge energy but limited acceptable charging energy, and continued charging can easily lead to overcharging; a low SBC indicates sufficient acceptable charging energy but limited discharge energy, and continued discharging can easily lead to over-discharging. Therefore, SBC is the basis for determining the frequency division point and power allocation of an energy storage system.

[0073] The preset state of charge range refers to a reference range set for the state of charge of an energy storage system. Within this reference range, the energy storage system can safely and efficiently perform charging and discharging operations without the risk of overcharging or over-discharging.

[0074] The upper and lower limits of the preset state of charge (SOC) range can be pre-calibrated based on the type of energy storage system, its electrochemical characteristics, and its operating strategy. For example, for a lithium-ion battery power energy storage system, the preset SOC range can be set to 10% to 90%; for a sodium-ion battery power energy storage system, the preset SOC range can be set to 30% to 70%. When the actual SOC of the energy storage system is lower than the lower limit or higher than the upper limit, or within the preset range of the lower or upper limit (e.g., close to the upper or lower limit), it is considered to be in a non-ideal operating state, and the initial frequency division point needs to be adjusted.

[0075] In some embodiments, a preset state of charge range for the power-type energy storage system and a preset state of charge range for the energy-type energy storage system can be preset. For example, the preset state of charge range for the power-type energy storage system is [30%, 70%], where 30% is the lower limit of the preset state of charge range and 70% is the upper limit of the preset state of charge range.

[0076] In some embodiments, when the state of charge of a power energy storage system is outside a preset state of charge range, such as when the state of charge of the power energy storage system is higher than the upper limit (e.g., more than 70%), it indicates that it is at a high level of charge; or when the state of charge of the power energy storage system is lower than the lower limit (e.g., less than 30%), it indicates that it is at a low level of charge.

[0077] In one possible embodiment, the initial frequency division point can be adjusted using an adjustment coefficient. For example, the target frequency division point is equal to the initial frequency division point multiplied by the adjustment coefficient k. The adjustment coefficient k can be calculated based on the degree of deviation of SOC_p from the preset state of charge range. For instance, the current state of charge of the power storage system can be obtained, denoted as SOC_p, with the lower limit of the preset state of charge range denoted as SOC_min and the upper limit as SOC_max. When SOC_p is between SOC_min and SOC_max, the adjustment coefficient k equals 1, and the target frequency division point equals the initial frequency division point. When SOC_p is less than SOC_min, the deviation degree d = (SOC_min - SOC_p) / SOC_min is calculated, and the adjustment coefficient k = 1 + α1 * d, where α1 is a preset intensity coefficient. When SOC_p is greater than SOC_max, the deviation degree d = (SOC_p - SOC_max) / (100% - SOC_max) is calculated, and the adjustment coefficient k = 1 + β1 * d, where β1 is also a preset intensity coefficient. α1 and β1 can be determined based on experiments or experience.

[0078] Through the above linear mapping, the greater the deviation, the greater the increase in the crossover point, and the greater the transfer of high-frequency power components. To ensure smooth control, the rate of change of the target crossover point can be limited to prevent abrupt changes in the crossover point from causing drastic jumps in the power allocation result.

[0079] In one possible embodiment, a segmented adjustment strategy can be employed. Multiple state-of-charge intervals are pre-defined, with each interval corresponding to an adjustment factor at a frequency division point. For example, when SOC_p is between 30% and 70%, the target frequency division point is equal to the initial frequency division point (without increasing it); when SOC_p is between 20% and 30% or between 70% and 80%, the target frequency division point can be equal to 1.1 times the initial frequency division point (to appropriately increase the power value that the energy storage system should bear and appropriately decrease the power value that the power storage system should bear); when SOC_p is between 10% and 20% or between 80% and 90%, the target frequency division point can be equal to 1.5 times the initial frequency division point (to increase the power value that the energy storage system should bear and decrease the power value that the power storage system should bear); when SOC_p is below 10% or above 90%, the target frequency division point can be equal to 2 times the initial frequency division point (to significantly increase the power value that the energy storage system should bear and significantly decrease the power value that the power storage system should bear).

[0080] In some embodiments, the adjustment strategy for the initial frequency division point can differ depending on whether it is in the discharge direction or the charging direction.

[0081] It is worth noting that the above description only uses the state of charge (SBC) of power-type energy storage systems as the basis for adjustment. However, in practical applications, the SBC of energy-type energy storage systems can also be considered for comprehensive decision-making. This application does not limit this aspect.

[0082] In some embodiments, based on the battery operating status of each energy storage system, the specified power allocation result is corrected to obtain the target power allocation result corresponding to the power-type energy storage system and the energy-type energy storage system, including: Determine the relationship between the state of charge (SOC) of the power-type energy storage system and the preset SOC range. When the state of charge of the power-type energy storage system is outside the corresponding preset state of charge range, the power allocation result corresponding to the power-type energy storage system is reduced, and the power allocation result corresponding to the energy-type energy storage system is increased, so as to obtain the target power allocation result corresponding to the power-type energy storage system and the energy-type energy storage system respectively.

[0083] When the state of charge of a power-type energy storage system is outside the corresponding preset state of charge range, the specified power allocation result may include the initial power allocation result of the power-type energy storage system and the initial power allocation result of the energy-type energy storage system.

[0084] In some embodiments, reducing the power allocation result corresponding to the power storage system means multiplying the power allocation result obtained in the aforementioned steps (e.g., the high-frequency power component that the power storage system should bear, obtained through frequency domain decomposition) by a coefficient less than 1, or subtracting an adjustment amount, thereby obtaining a smaller power allocation result.

[0085] In some embodiments, while keeping the total power demand information unchanged, the reduced power value of the power-type energy storage system is added to the power allocation result of the energy-type energy storage system.

[0086] It is understandable that, before and after the correction, the reduction in the power value that the power-type energy storage system should bear is equal to the increase in the power value that the energy-type energy storage system should bear, so that the sum of the two new target power allocation results equals the original total power demand information.

[0087] In some embodiments, the power allocation result of the power-type energy storage system can be corrected using a power reduction factor γ. The reduction factor γ can be calculated based on the degree of deviation of SOC_p from a preset state of charge range. For example, the current state of charge of the power-type energy storage system can be obtained, denoted as SOC_p. When SOC_p is between SOC_min and SOC_max, γ equals 1, meaning the power allocation result of the power-type energy storage system is not reduced. When SOC_p is less than SOC_min, the deviation degree d_dis = (SOC_min - SOC_p) / SOC_min is calculated, and γ is set to max(0, 1 - α2 * d_dis), where α2 is a preset intensity coefficient. The value of γ ranges from 0 to 1; the greater the deviation, the smaller γ, and the greater the reduction in power value that the power-type energy storage system should bear. When SOC_p is greater than SOC_max, the deviation degree d_ch = (SOC_p - SOC_max) / (100% - SOC_max) is calculated, and γ = max(0, 1 - β2 * d_ch) is set, where β2 is also a preset intensity coefficient. Then, the original power allocation result of the power-type energy storage system (denoted as P_P_orig) is multiplied by γ to obtain the target power allocation result of the power-type energy storage system, denoted as P_P_target = γ × P_P_orig. At the same time, a correction amount ΔP = P_P_orig - P_P_target is added to the original power allocation result of the energy-type energy storage system (denoted as P_E_orig) to obtain the target power allocation result of the energy-type energy storage system: P_E_target = P_E_orig + ΔP; Where P_P_target + P_E_target = P_P_orig + P_E_orig, the total power demand remains constant. α2 and β2 can be determined experimentally or empirically.

[0088] It is worth noting that the power allocation result corresponding to the power-type energy storage system can be reduced while keeping the total power demand information unchanged. In some cases, when the state of charge of the power-type energy storage system deviates significantly from the preset state of charge range (e.g., below 5%), γ can be set to 0, that is, the response of a certain type of energy storage system is stopped, such as the response of the power-type energy storage system, and all power is borne by the energy-type energy storage system.

[0089] It should be understood that by correcting the corresponding power allocation results based on the state of charge, the hybrid energy storage system can automatically reduce the power load of the power-type energy storage system when it is at risk of overcharging or over-discharging, and transfer part of its power load to the energy-type energy storage system. This effectively protects the power-type energy storage system, extends its cycle life, and ensures that the entire system can still maintain its power support capability to the grid as much as possible when unsafe boundaries occur.

[0090] It should be noted that for power-type energy storage battery systems, a relatively central preset state of charge range is usually set, such as approximately 30% to 70%. This preset state of charge range is to ensure that the power-type energy storage battery system always has sufficient adjustment space for charging and discharging during operation, so as to continuously undertake the tasks of frequency support and high-frequency power regulation. Moreover, operating within this preset state of charge range is optimal for the lifespan of the energy storage system.

[0091] Taking sodium-ion battery energy storage systems as power-type energy storage systems and lithium-ion battery energy storage systems as energy-type energy storage systems as examples, if the state of charge (SOC) of a power-type energy storage system is close to the upper or lower limit of its corresponding preset SOC range, its charge and discharge regulation capability will be limited, hindering its participation in rapid frequency regulation. For lithium-ion battery energy storage systems, which primarily undertake energy-type regulation tasks such as load tracking or low-frequency power balancing, the preset SOC range can usually be set wider, such as within a larger SOC range (5%–95% or even 0%–100%), rather than strictly maintaining it within a relatively central preset SOC range. In other words, lithium-ion battery energy storage systems are more used to provide energy capacity support, while sodium-ion battery energy storage systems are more used for rapid response.

[0092] During the operation of the hybrid energy storage system, the EMS (Energy Management System) continuously monitors the State of Charge (SOC) of both energy storage systems and dynamically adjusts the power allocation strategy based on the SOC. When the SOC of the sodium-ion battery energy storage system approaches its corresponding preset state of charge range, the EMS reduces the power it bears and allocates more regulation tasks to the lithium-ion battery energy storage system to prevent the SOC of the sodium-ion battery energy storage system from continuing to deviate towards the boundary.

[0093] When the State of Charge (SOC) of both energy storage systems is outside their respective preset state of charge ranges, the Energy Management System (EMS) can readjust the allocation of charging and discharging power or configure compensatory charging and discharging operations to gradually bring one of the energy storage systems back to its corresponding preset state of charge range. For example, this can be achieved by prioritizing the charging and discharging regulation of lithium-ion batteries.

[0094] In terms of design principles, priority is usually given to maintaining the state of charge (SOC) of sodium-ion batteries within their corresponding preset range. This is because sodium-ion battery energy storage systems are responsible for rapid power response and frequency support, requiring bidirectional regulation capabilities. If the SOC of a sodium-ion battery energy storage system is close to full charge or close to depletion, it will affect the system's ability to participate in frequency regulation.

[0095] By prioritizing the maintenance of sodium-ion battery energy storage systems within a suitable SOC range and utilizing lithium-ion batteries to undertake more energy-type regulation power distribution tasks, the two types of energy storage systems can complement each other in terms of power response capability and energy capacity, thereby improving the operational stability and regulation efficiency of the entire hybrid energy storage system.

[0096] It should be understood that the preset state of charge range, the calculation method of the adjustment coefficient γ, and the value of the adjustment intensity coefficient can all be flexibly configured according to the actual situation, and the embodiments of this application are not limited in this regard.

[0097] In some embodiments, the method further includes: If the target power allocation result for a certain type of energy storage system is not within the corresponding allocable power range, the target power allocation result for that type of energy storage system will be adjusted, and the target power allocation result for another type of energy storage system will be adjusted according to the adjusted power value. If the target power allocation results for both the power-type energy storage system and the energy-type energy storage system are not within the corresponding allocable power range, the target power allocation results for both the power-type energy storage system and the energy-type energy storage system will be adjusted. To obtain new target power allocation results for power-type energy storage systems and / or energy-type energy storage systems.

[0098] The target power allocation result refers to the power value to be allocated to each energy storage system based on a specific energy management strategy (such as filtering, optimization or rule-based methods). The target power allocation result can be positive or negative, where a positive value indicates discharging and a negative value indicates charging.

[0099] The allocable power range refers to the power interval allowed for each energy storage system under physical or safe operating conditions. This range can be defined by a maximum allocable power (upper limit) and a minimum allocable power (lower limit). Adjustment refers to setting the target power allocation result as a boundary value (upper or lower limit) when it is outside the allocable power range, and calculating the difference before and after adjustment as the adjusted power value.

[0100] The new target power allocation result refers to the actual power value finally issued to each energy storage system after the above adjustments.

[0101] In some embodiments, the target power allocation result of the energy storage system includes the target power value of the energy storage system. If only one type of energy storage system exists, for example, the target power allocation result of a power-type energy storage system is not within its allocable power range (e.g., the target power value of the power-type energy storage system is 80 kW, while its maximum allocable power is only 50 kW), then the target power allocation result of the power-type energy storage system is adjusted: it is reduced to 50 kW, that is, adjusted to the maximum allocable power of the power-type energy storage system. The adjusted power value is calculated, that is, the difference before and after the adjustment, which is 30 kW (80 kW minus 50 kW). In order to keep the total demand power as constant as possible, the target power allocation result of another type of energy storage system, namely the energy-type energy storage system, needs to be adjusted according to the adjusted power value. Specifically, since the power-type energy storage system reduces the discharge power by 30 kW, the energy-type energy storage system should bear the additional 30 kW of power value, therefore the original target power value of the energy-type energy storage system is increased by 30 kW. If the increased power value does not exceed the allocable power range corresponding to the energy storage system, the adjustment is complete, and a new target power allocation result is obtained: 50 kW for the power storage system and 30 kW for the energy storage system. Conversely, if the increased target power value of the energy storage system also exceeds its corresponding maximum allocable power, the target power value of the energy storage system will be further adjusted to its corresponding maximum allocable power.

[0102] In some embodiments, if the target power allocation results for both the power-type energy storage system and the energy-type energy storage system are not within their respective allocable power ranges, then adjustments are made to both: the power-type energy storage system is adjusted to the boundary value of its corresponding allocable power range, and the energy-type energy storage system is adjusted to the boundary value of its corresponding allocable power range.

[0103] After the above steps, new target power allocation results are obtained for the power-type energy storage system and / or the energy-type energy storage system. It is possible that only one type of energy storage system is adjusted, or both types are adjusted. The new target power allocation results satisfy the following: the new target power allocation result for each energy storage system falls within its corresponding allocable power range. In actual control, the actual total power corresponding to the new target power allocation result is determined. If the actual total power cannot meet the original total power demand information, the energy management system issues a prompt message to reduce the desired power or activate the backup power supply, etc.

[0104] It should be understood that through the above adjustments, the maximum power output or maximum power absorption of each energy storage system under the current battery operating state is satisfied, while also approximating the total power demand information as closely as possible, thus achieving optimal power allocation under physical constraints. Subsequently, these new target power allocation results are sent to the first and second energy storage converters respectively. The first and second energy storage converters then charge or discharge the grid through their respective corresponding grid control algorithms, further enhancing the safety and robustness of the hybrid energy storage system and avoiding control failures or equipment damage caused by grid dispatch commands exceeding actual physical capabilities.

[0105] In some embodiments, the control parameters of the grid control algorithms corresponding to the first energy storage converter and the second energy storage converter are determined based on the grid operating status and the battery operating status of the connected energy storage system, respectively.

[0106] The control parameters include at least one of the virtual inertia coefficient, droop coefficient, and damping coefficient.

[0107] The virtual inertia coefficient determines the power support strength provided by the energy storage converter in simulating the rotor inertia of a synchronous generator when the grid frequency changes. A larger value indicates a stronger response of the energy storage converter to the rate of frequency change, enabling it to provide greater inertia-supported power. The droop coefficient (also known as the active-frequency droop coefficient or the voltage-no-voltage droop coefficient) determines the power output of the energy storage converter according to its droop characteristics when the grid steady-state frequency or voltage deviates from its rated value. A larger value indicates a larger response amplitude for primary frequency or voltage regulation. The damping coefficient is used to suppress oscillations in the converter's output power. A larger value results in a smoother dynamic process for the power response, but the response speed may be slower.

[0108] In some embodiments, the control parameters of the grid control algorithms corresponding to the first and second energy storage converters can be dynamically determined based on the grid operating status and the battery operating status of the energy storage systems connected to each energy storage converter. That is, the control parameters of the first energy storage converter are determined based on the grid operating status collected by the first energy storage converter and the battery operating status of the power-type energy storage system; the control parameters of the second energy storage converter are determined based on the grid operating status collected by the second energy storage converter and the battery operating status of the energy-type energy storage system.

[0109] In some embodiments, the three control parameters can be adjusted independently or in combination.

[0110] It should be noted that the adjustment range and strategy of the control parameters of the first and second energy storage converters can differ due to the different types of energy storage systems they are connected to. The first energy storage converter connected to a power-type energy storage system can use a larger virtual inertia coefficient to fully utilize its fast response advantage; the second energy storage converter connected to an energy-type energy storage system can use a relatively smaller virtual inertia coefficient to avoid frequent charging and discharging affecting its lifespan.

[0111] In some embodiments, when a preset change condition is detected in the power grid operating state... A first power command is generated based on a first power value and sent to a first energy storage converter, so that the first energy storage converter controls the power-type energy storage system to perform charging or discharging operations based on the first power command; and a second power command is generated based on a second power value and sent to a second energy storage converter, so that the second energy storage converter controls the energy-type energy storage system to perform charging or discharging operations based on the second power command.

[0112] The preset change conditions may include, but are not limited to, the following: the rate of change of the grid frequency exceeds a preset threshold (e.g., more than 0.5 Hz per second); the deviation of the grid frequency from the rated value exceeds a preset range (e.g., more than ±0.1 Hz); the effective value of the grid voltage experiences a sudden rise or fall, such as a change exceeding a preset threshold (e.g., more than 10 percent of the rated voltage); or disturbance events such as islanding switching or short-circuit faults are detected in the grid. When any of the above preset change conditions is met, it indicates that the grid operating state meets the preset change conditions.

[0113] In some embodiments, the energy-type energy storage system includes a lithium battery energy storage system, and the power-type energy storage system includes a sodium battery energy storage system.

[0114] It should be noted that the above description of the process is merely for illustration and explanation, and does not limit the scope of application of the embodiments of this application. Those skilled in the art can make various modifications and changes to the process under the guidance of the embodiments of this application. However, these modifications and changes are still within the scope of the embodiments of this application.

[0115] One or more embodiments of this application also provide a hybrid energy storage system. The hybrid energy storage system includes an energy management system, a power-type energy storage system, and an energy-type energy storage system. The power-type energy storage system is connected to the power grid through a first energy storage converter, and the energy-type energy storage system is connected to the power grid through a second energy storage converter. The energy management system is communicatively connected to both the first and second energy storage converters. The energy management system is configured as follows: Acquire the grid operating status and the battery operating status of the connected energy storage system from the first and second energy storage converters; Calculate total power demand information based on grid operating status and grid dispatch instructions; Power allocation is performed based on total power demand information to obtain the target power allocation results for power-type energy storage systems and energy-type energy storage systems respectively. The first and second energy storage converters control the connected energy storage systems to perform charging or discharging operations based on the target power allocation results of the connected energy storage systems and through their respective network control algorithms.

[0116] To better understand the above scheme, the control method of the hybrid energy storage system will be explained below with a specific embodiment.

[0117] Step 1: The grid-type energy storage converters connected to various energy storage systems monitor the grid operating status in real time. The grid operating status may include, but is not limited to, information such as grid frequency, frequency deviation, frequency change rate, voltage, and grid power exchange, which are used to determine the current operating status of the grid.

[0118] Step 2: Each energy storage converter uploads the detected grid operating status and the battery operating status within the connected energy storage system to the energy management system. The battery operating status may include, but is not limited to, the state of charge (SOC) of the sodium-ion battery energy storage system, the SOC of the lithium-ion battery energy storage system, power capacity (also known as the allocable power range), battery temperature, and the operating status of the energy storage converter itself.

[0119] Step 3: The energy management system calculates the power support requirements of the system based on the grid's frequency deviation, frequency change rate, and grid dispatch instructions, generating total power demand information. This total power demand information is used to characterize the power that various energy storage systems should inject into or absorb from the grid at different times.

[0120] Step 4: The energy management system performs frequency decomposition processing on the total power demand information, breaking it down into high-frequency power components and low-frequency power components. The high-frequency power components correspond to power demand changes over short timescales, while the low-frequency power components correspond to power demand changes over longer durations.

[0121] Step 5: Based on the structural characteristics of various energy storage systems and their battery operating status, the energy management system prioritizes allocating high-frequency power components to sodium-ion battery energy storage systems and low-frequency power components to lithium-ion battery energy storage systems to obtain the initial power allocation result. The initial power allocation result is then corrected by considering constraints such as battery state of charge and battery power limits to obtain the target power allocation result.

[0122] Step 6: The energy management system generates corresponding power commands based on the power allocation results and sends them to the energy storage converters connected to the sodium-ion battery energy storage system and the lithium-ion battery energy storage system, respectively, as the power control targets for each energy storage converter.

[0123] Step 7: Each energy storage converter adjusts its output voltage, frequency, and power according to the received power reference command and in conjunction with the grid control algorithm, such as the virtual synchronous machine control algorithm, droop control algorithm, or virtual inertia control algorithm, thereby achieving power support for the grid.

[0124] During operation, each energy storage converter continuously monitors the output power, grid status, and battery operating status, and feeds this information back to the energy management system in real time. Based on this feedback, the energy management system recalculates the total power demand and dynamically adjusts the power allocation strategy, thus achieving real-time control.

[0125] Through the above process, the coordinated operation and stable control of the grid-type sodium-lithium hybrid energy storage system under different power grid operating conditions can be achieved.

[0126] For example, such as Figure 3 As shown, the energy storage power station is configured as follows: The lithium-ion battery energy storage system has a rated power of 90MW and a rated energy of 360MWh. The sodium-ion battery energy storage system has a rated power of 10MW and a rated energy of 40MWh. Both types of energy storage systems are connected to the same AC bus via a grid-type PCS (also known as an energy storage converter), and are coordinated and controlled by a unified energy management system.

[0127] Under normal grid connection and stable operation: When the power grid is operating stably and the power grid frequency is within the rated range, the PCS of each grid type maintains the voltage amplitude and frequency reference value at the power station output.

[0128] In addition, the sodium-ion battery energy storage system is controlled within the state of charge range of 30% to 70% and kept in standby mode, only undertaking a small amount of power; the lithium-ion battery energy storage system undertakes the task of basic power output of the power station according to the grid dispatch instructions.

[0129] Under conditions of rapid fluctuations in power grid frequency: When the grid frequency deviates from the rated value for a short period of time (e.g., due to sudden load changes), the PCS of each grid type detects the frequency deviation and the rate of frequency change, and the corresponding PCS controls the sodium-ion battery energy storage system to inject power into the grid or absorb power.

[0130] During this process, the sodium-ion battery energy storage system responds rapidly within milliseconds, outputting high-frequency bidirectional power changes to suppress frequency fluctuations; the lithium-ion battery energy storage system maintains its original power capacity and does not participate in rapid power oscillations.

[0131] Under continuous frequency modulation operation: When the power grid enters continuous frequency regulation mode, the sodium-ion battery energy storage system continuously participates in frequency regulation, and its SOC usually fluctuates slightly within the range of 30% to 70%. When the SOC of the sodium-ion battery energy storage system is detected to be close to the boundary of 70% or 30%, the corresponding grid-type PCS reduces the power amplitude that the sodium-ion battery energy storage system should bear, while gradually increasing the power amplitude that the lithium-ion battery should bear.

[0132] In the case of SOC pullback in sodium-ion batteries: When the grid load is low or charging conditions are available, the lithium-ion battery energy storage system takes priority in energy regulation tasks. By adjusting the output power, the SOC of the sodium-ion battery energy storage system is brought back to near the midpoint of the preset state of charge range. During this correction process, the sodium-ion battery only participates in necessary frequency fine-tuning and does not undertake the task of continuous energy output.

[0133] Under intraday peak-shaving operation: During peak daily load periods of the power grid, the lithium-ion battery pure energy storage system continuously discharges according to the grid dispatch instructions to complete the power station's peak shaving task; the sodium-ion battery energy storage system only intervenes briefly when there are fluctuations in the grid frequency to provide frequency support.

[0134] Through the above methods, the energy storage power station can maintain stable output voltage and frequency while achieving coordinated operation of sodium-ion battery energy storage system and lithium-ion battery energy storage system at different time scales, meeting various operational requirements such as frequency regulation, inertial response and peak shaving.

[0135] Figure 4 This is a schematic diagram of the structure of the control device of a hybrid energy storage system according to some embodiments of the present application.

[0136] like Figure 4 As shown, one or more embodiments of this application also provide a structural schematic diagram of a control device for a hybrid energy storage system. The control device for the hybrid energy storage system may include: The acquisition module 401 is used to acquire the grid operation status and the battery operation status of the connected energy storage system collected by the first energy storage converter and the second energy storage converter. Calculation module 402 is used to calculate total power demand information based on the power grid operating status and power grid dispatch instructions; The allocation module 403 is used to perform power allocation based on the total power demand information to obtain the target power allocation results for the power-type energy storage system and the energy-type energy storage system respectively. The control module 404 is used to control the first energy storage converter and the second energy storage converter to instruct the connected energy storage system to perform charging or discharging operations based on the target power allocation result of the connected energy storage system through their respective network control algorithms.

[0137] The acquisition module 401, calculation module 402, allocation module 403 and control module 404 can be used to execute the corresponding embodiments of the control method of the above-mentioned hybrid energy storage system. For the specific implementation of these modules and more details, please refer to the corresponding method section, which will not be elaborated here.

[0138] In some embodiments of this application, the control device for the hybrid energy storage system can be implemented as a computer program, which can be implemented in, for example... Figure 5 The device operates on the electronic device shown. The memory of the electronic device can store various program modules that constitute the control device of the hybrid energy storage system. The computer program composed of the various program modules causes the processor to execute the steps in the control method of the hybrid energy storage system of the various embodiments of this application described in the embodiments of this application.

[0139] For details on the implementation of each of the above operations, please refer to the previous examples, which will not be repeated here.

[0140] Figure 5 This is a schematic diagram of the structure of an electronic device according to some embodiments of the present application.

[0141] This application embodiment also provides an electronic device 500, which may include components such as a processor 501 with one or more processing cores, a memory 502 with one or more computer-readable storage media, a power supply 503, and an input unit 504. Those skilled in the art will understand that... Figure 5 The electronic device structure shown does not constitute a limitation on the electronic device and may include more or fewer components than shown, or combine certain components, or have different component arrangements. Wherein: Processor 501 is the control center of the electronic device, connecting various parts of the device via various interfaces and lines. It executes software programs and / or modules stored in memory 502, and calls data stored in memory 502, to perform various functions and process data. It is understood that processor 501 communicates with the controller via signal transmission. Optionally, processor 501 may include one or more processing cores; preferably, processor 501 may integrate an application processor and a modem processor, wherein the application processor mainly handles the operating system, user interface, and applications, while the modem processor mainly handles wireless communication. It is understood that the modem processor may also not be integrated into processor 501.

[0142] The memory 502 can be used to store software programs and modules. The processor 501 executes various functional applications and data processing by running the software programs and modules stored in the memory 502. The memory 502 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, application programs required for at least one function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the electronic device, etc. In addition, the memory 502 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, the memory 502 may also include a memory controller to provide the processor 501 with access to the memory 502.

[0143] The electronic device also includes a power supply 503 that supplies power to various components. Preferably, the power supply 503 can be logically connected to the processor 501 through a power management system, thereby enabling functions such as charging, discharging, and power consumption management through the power management system. The power supply 503 may also include one or more DC or AC power supplies, recharging systems, power fault detection circuits, power converters or inverters, power status indicators, and other arbitrary components.

[0144] The electronic device may also include an input unit 504, which can be used to receive input digital or character information and generate keyboard, mouse, joystick, optical or trackball signal inputs related to user settings and function control.

[0145] Although not shown, the electronic device may also include a display unit, etc., which will not be described in detail here. Specifically, in this embodiment, the processor 501 in the electronic device loads the executable files corresponding to the processes of one or more application programs into the memory 502 according to computer instructions, and the processor 501 runs the application programs stored in the memory 502 to realize various functions, such as the control method of the hybrid energy storage system of the various embodiments of this application described in the embodiments of this application.

[0146] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0147] It should be noted that, Figure 5 This is merely one implementation of the electronic device 500 provided in this application embodiment. In actual applications, the electronic device 500 may include more or fewer components, which is not limited here.

[0148] It should be understood that the various solutions in the embodiments of this application can be used in a reasonable combination, and the explanations or descriptions of the various terms appearing in the embodiments can be referenced or explained to each other in the various embodiments, without limitation.

[0149] Based on the above embodiments and the same concept, this application also provides a computer-readable storage medium storing a computer program that, when run on a computer, causes the computer to perform the method provided in the above embodiments.

[0150] Based on the above embodiments and the same concept, this application also provides a computer program product, including a computer program or instructions, which, when executed by a processor, performs the method provided in the above embodiments.

[0151] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the detailed descriptions of other embodiments above, which will not be repeated here.

[0152] In practice, each of the above units or structures can be implemented as an independent entity or can be arbitrarily combined to be implemented as the same or several entities. For the specific implementation of each of the above units or structures, please refer to the previous method embodiments, which will not be repeated here.

[0153] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of this application. The description of the embodiments above is only for the purpose of helping to understand the methods and core ideas of the embodiments of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the embodiments of this application. Therefore, the content of the embodiments of this application should not be construed as a limitation of this application.

Claims

1. A control method for a hybrid energy storage system, characterized in that, The hybrid energy storage system includes a power-type energy storage system and an energy-type energy storage system. The power-type energy storage system is connected to the power grid via a first energy storage converter, and the energy-type energy storage system is connected to the power grid via a second energy storage converter. The method includes: Acquire the grid operating status and the battery operating status of the connected energy storage system collected by the first energy storage converter and the second energy storage converter; Based on the power grid operating status and power grid dispatch instructions, calculate the total power demand information; Based on the total power demand information, power allocation is performed to obtain the target power allocation results for the power-type energy storage system and the energy-type energy storage system, respectively. The first energy storage converter and the second energy storage converter control each other to instruct the connected energy storage system to perform charging or discharging operations based on the target power allocation result of the connected energy storage system through their respective network control algorithms.

2. The control method for the hybrid energy storage system according to claim 1, characterized in that, The battery operating state includes at least one of the energy storage system's state of charge and the allocable power range. The process of allocating power based on the total power demand information to obtain the target power allocation results for the power-type energy storage system and the energy-type energy storage system respectively includes: Based on the total power demand information, power allocation is performed to obtain the power allocation results for the power-type energy storage system and the energy-type energy storage system, respectively. Based on the battery operating status of each of the energy storage systems, the specified power allocation results are corrected to obtain the target power allocation results corresponding to the power-type energy storage system and the energy-type energy storage system, respectively.

3. The control method for the hybrid energy storage system according to claim 2, characterized in that, The step of allocating power based on the total power demand information to obtain the power allocation results for the power-type energy storage system and the energy-type energy storage system respectively includes: The target frequency division point is determined based on the battery operating status of the power-type energy storage system and / or the energy-type energy storage system. Based on the target frequency division point, the total power demand information is decomposed in the frequency domain to obtain high-frequency power components and low-frequency power components. The high-frequency power component is used as the power allocation result corresponding to the power-type energy storage system, and the low-frequency power component is used as the power allocation result corresponding to the energy-type energy storage system.

4. The control method for the hybrid energy storage system according to claim 3, characterized in that, Determining the target frequency division point based on the battery operating status of the power-type energy storage system and / or the energy-type energy storage system includes: When the state of charge of the power-type energy storage system is outside the corresponding preset state of charge range, the initial frequency division point is increased to obtain the target frequency division point.

5. The control method for the hybrid energy storage system according to claim 2, characterized in that, The step of correcting the specified power allocation result based on the battery operating status of each of the energy storage systems to obtain the target power allocation result corresponding to each of the power-type energy storage system and the energy-type energy storage system includes: Determine the relationship between the state of charge (SOC) of the power-type energy storage system and the preset SOC range. When the state of charge of the power-type energy storage system is outside the corresponding preset state of charge range, the power allocation result corresponding to the power-type energy storage system is reduced, and the power allocation result corresponding to the energy-type energy storage system is increased, so as to obtain the target power allocation result corresponding to the power-type energy storage system and the energy-type energy storage system respectively.

6. The control method for the hybrid energy storage system according to claim 2, characterized in that, After obtaining the target power allocation results corresponding to the power-type energy storage system and the energy-type energy storage system respectively, the method further includes: If the target power allocation result for one type of energy storage system is not within the corresponding allocable power range, the target power allocation result for that type of energy storage system is adjusted, and the target power allocation result for another type of energy storage system is adjusted according to the adjusted power value; or, If the target power allocation results for both the power-type energy storage system and the energy-type energy storage system are not within the corresponding allocable power range, the target power allocation results for both the power-type energy storage system and the energy-type energy storage system shall be adjusted. To obtain new target power allocation results corresponding to the power-type energy storage system and / or the energy-type energy storage system.

7. The control method for a hybrid energy storage system according to any one of claims 1 to 6, characterized in that, The control parameters of the grid control algorithms corresponding to the first energy storage converter and the second energy storage converter are determined based on the grid operating status and the battery operating status of the connected energy storage system, respectively. The control parameters include at least one of the virtual inertia coefficient, droop coefficient, and damping coefficient.

8. The control method for a hybrid energy storage system according to any one of claims 1 to 6, characterized in that, The energy storage system includes a lithium battery energy storage system, and the power storage system includes a sodium battery energy storage system.

9. A hybrid energy storage system, characterized in that, The hybrid energy storage system includes an energy management system, a power-type energy storage system, and an energy-type energy storage system. The power-type energy storage system is connected to the power grid via a first energy storage converter, and the energy-type energy storage system is connected to the power grid via a second energy storage converter. The energy management system is communicatively connected to both the first and second energy storage converters. The energy management system is configured as follows: Acquire the grid operating status and the battery operating status of the connected energy storage system collected by the first energy storage converter and the second energy storage converter; Based on the power grid operating status and power grid dispatch instructions, calculate the total power demand information; Based on the total power demand information, power allocation is performed to obtain the target power allocation results for the power-type energy storage system and the energy-type energy storage system, respectively. The first energy storage converter and the second energy storage converter control each other to instruct the connected energy storage system to perform charging or discharging operations based on the target power allocation result of the connected energy storage system through their respective network control algorithms.

10. An electronic device, characterized in that, include: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the steps of the method according to any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that, It stores a computer program thereon, which, when executed by a processor, implements the steps of the method according to any one of claims 1 to 8.

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