Supercapacitor coupled lithium battery energy storage frequency modulation power distribution method and related devices

Abstract

The application discloses a super capacitor coupled lithium battery energy storage frequency modulation power distribution method and related equipment, and relates to the technical field of hybrid energy storage frequency modulation. The method obtains a power grid frequency modulation instruction, a super capacitor state of charge and a lithium battery state of charge; frequency decomposition and reconstruction are performed on the power grid frequency modulation instruction to obtain a high-frequency power component; a feedback weighting factor is determined according to the super capacitor state of charge, the high-frequency power component is weighted, and amplitude limiting is performed according to a super capacitor dynamic charging and discharging power boundary to obtain a super capacitor distributed power; a power deficiency is determined according to the power grid frequency modulation instruction and the super capacitor distributed power, a life weighting factor is determined according to the lithium battery state of charge, the power deficiency is weighted, and amplitude limiting is performed according to a lithium battery dynamic charging and discharging power boundary to obtain a lithium battery distributed power. The application can adapt the power distribution result to the state of charge and the allowed charging and discharging capacity of the two types of energy storage units.

Description

Technical Field

[0001] This application belongs to the field of hybrid energy storage power control technology, specifically involving a method for frequency modulation power distribution of supercapacitor-coupled lithium battery energy storage and related equipment. Background Technology

[0002] As the scale of new energy power generation continues to expand, power fluctuations and frequency deviations in the power grid are becoming more frequent, requiring energy storage systems to respond quickly to grid frequency regulation commands. Supercapacitors are characterized by high power density, fast charge and discharge response, and long cycle life, while lithium batteries are characterized by high energy density and strong continuous power supply capability. Therefore, supercapacitors and lithium batteries can be coupled to form a hybrid energy storage system, with both types of energy storage units jointly undertaking the power demand for grid frequency regulation.

[0003] Existing hybrid energy storage frequency regulation schemes typically allocate grid frequency regulation commands to supercapacitors and lithium batteries according to preset frequency bands or fixed ratios. However, the state of charge (SOC) of supercapacitors and lithium batteries changes dynamically during charging and discharging, and their permissible charging and discharging power is limited by operating parameters such as terminal voltage, maximum permissible current, and internal resistance. When using a fixed allocation method, it is difficult to adjust the power allocation based on the real-time SOC and dynamic charging and discharging capabilities of the two types of energy storage units. This can easily cause the energy storage units to deviate from their optimal operating state or cause the allocated power to exceed the current permissible range, affecting the hybrid energy storage system's ability to continuously execute grid frequency regulation commands. Summary of the Invention

[0004] The purpose of this application is to provide a method and related equipment for frequency modulation power allocation of supercapacitor-coupled lithium battery energy storage, so as to overcome the technical problem that the existing technology fails to combine the real-time state of charge and dynamic charge and discharge capabilities of supercapacitors and lithium batteries for power allocation, resulting in the power allocation results being difficult to adapt to the current operating state of the two types of energy storage units.

[0005] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, this application provides a method for frequency modulation power distribution in supercapacitor-coupled lithium battery energy storage, comprising: The grid frequency regulation command, the state of charge of the supercapacitor, and the state of charge of the lithium battery are obtained. The grid frequency regulation command is decomposed and reconstructed to obtain the high-frequency power component. The feedback weighting factor is determined based on the state of charge of the supercapacitor; the high-frequency power components are weighted according to the feedback weighting factor to obtain the supercapacitor reference power; The current terminal voltage of the supercapacitor is determined based on the state of charge of the supercapacitor, and the dynamic charging and discharging power boundary of the supercapacitor is determined based on the current terminal voltage, the preset maximum allowable current of the supercapacitor, and the equivalent series internal resistance. The reference power of the supercapacitor is limited according to the dynamic charging and discharging power boundary of the supercapacitor to obtain the allocated power of the supercapacitor. The power deficit is determined according to the power grid frequency regulation command and the power allocation of the supercapacitor. The power deficit is then weighted according to the lifetime weighting factor to obtain the lithium battery reference power. The lifetime weighting factor is determined based on the degree of deviation between the lithium battery state of charge and the preset optimal working state of charge. The current open-circuit voltage of the lithium battery is determined based on the state of charge of the lithium battery. The dynamic charge and discharge power boundary of the lithium battery is determined based on the current open-circuit voltage and the preset maximum allowable current and internal resistance parameters of the lithium battery. The reference power of the lithium battery is limited according to the dynamic charge and discharge power boundary of the lithium battery to obtain the lithium battery allocation power. The supercapacitor allocation power and the lithium battery allocation power are then output.

[0006] In one embodiment, the power grid frequency regulation command is frequency decomposed and reconstructed to obtain high-frequency power components, including: The power grid frequency regulation command is decomposed into multiple wavelet packets using the db4 wavelet basis to determine the frequency range corresponding to each decomposition node. The decomposition node corresponding to the target frequency range of 1 to 10 Hz is selected, and the selected decomposition node is reconstructed to obtain the high-frequency power component.

[0007] In one embodiment, the high-frequency power components are weighted according to a feedback weighting factor determined based on the supercapacitor's state of charge to obtain a supercapacitor reference power, including: The feedback weighting factor is determined according to the following formula:

[0008] In the formula, The feedback weighting factor is... This refers to the state of charge of the supercapacitor. and These are the preset upper and lower limits of the supercapacitor's state of charge; The product of the feedback weighting factor and the high-frequency power component is determined as the reference power of the supercapacitor.

[0009] In one embodiment, determining the current terminal voltage of the supercapacitor based on its state of charge, and determining the dynamic charging and discharging power boundary of the supercapacitor based on the current terminal voltage and a preset maximum allowable current and equivalent series internal resistance of the supercapacitor, includes: The current terminal voltage is determined according to the following formula:

[0010] The discharge power boundary of a supercapacitor is determined according to the following formula:

[0011] The charging power boundary of a supercapacitor is determined according to the following formula:

[0012] In the formula, The current terminal voltage, This refers to the state of charge of the supercapacitor. and These are the maximum and minimum terminal voltages of the supercapacitor, respectively. This is the maximum allowable current of the supercapacitor. The equivalent series internal resistance is... and These are the supercapacitor discharge power boundary and the supercapacitor charging power boundary, respectively.

[0013] In one embodiment, the power deficit is weighted according to a lifetime weighting factor to obtain a lithium battery reference power. The lifetime weighting factor is determined based on the deviation between the lithium battery's state of charge and a preset optimal operating state of charge, including: The lifetime weighting factor is determined according to the following formula:

[0014] In the formula, The lifetime weighting factor is... The state of charge of the lithium battery. This is the optimal state of charge. The standard deviation is the preset value. The product of the lifetime weighting factor and the power deficit is determined as the reference power of the lithium battery.

[0015] In one embodiment, the internal resistance parameters include ohmic internal resistance and charge transfer internal resistance; The current open-circuit voltage of the lithium battery is determined based on the state of charge of the lithium battery, and the dynamic charge / discharge power boundary of the lithium battery is determined based on the current open-circuit voltage and preset maximum allowable current and internal resistance parameters of the lithium battery, including: The current open-circuit voltage is determined according to the following formula:

[0016] The lithium battery discharge power boundary and lithium battery charging power boundary are determined according to the following formulas:

[0017]

[0018] In the formula, The current open-circuit voltage, The state of charge of the lithium battery. and These are the maximum and minimum open-circuit voltages of the lithium battery, respectively. This is the maximum allowable current of the lithium battery. The internal resistance is ohmic. The charge transfer internal resistance, and These are the lithium battery discharge power boundary and the lithium battery charging power boundary, respectively.

[0019] In one embodiment, after limiting the lithium battery reference power according to the lithium battery dynamic charge / discharge power boundary to obtain the lithium battery allocated power, the method further includes: Obtain the actual grid frequency, and based on the frequency deviation between the actual grid frequency and the rated frequency, determine the proportional-integral correction amount used to correct the sum of the supercapacitor's allocated power and the lithium battery's allocated power according to the following formula:

[0020] The total feedforward power is determined based on the supercapacitor power allocation and the lithium battery power allocation. The sum of the total feedforward power and the proportional-integral correction amount is determined as the total correction power target. The total correction power target is then output as the execution command of the power conversion system. In the formula, This is the proportional-integral correction amount. The frequency deviation is... and These are the proportional coefficient and the integral coefficient, respectively. The starting time of integration, This is the time variable for integration.

[0021] Secondly, this application provides a supercapacitor-coupled lithium battery energy storage frequency modulation power distribution system, comprising: The frequency decomposition module is used to acquire the power grid frequency regulation command, the state of charge of the supercapacitor and the state of charge of the lithium battery, and to perform frequency decomposition and reconstruction on the power grid frequency regulation command to obtain high-frequency power components. A supercapacitor reference power determination module is used to determine a feedback weighting factor based on the supercapacitor's state of charge; and to weight the high-frequency power components according to the feedback weighting factor to obtain the supercapacitor reference power. The supercapacitor power allocation module is used to determine the current terminal voltage of the supercapacitor based on the state of charge of the supercapacitor, and to determine the dynamic charging and discharging power boundary of the supercapacitor based on the current terminal voltage and the preset maximum allowable current and equivalent series internal resistance of the supercapacitor. The supercapacitor reference power is limited according to the dynamic charging and discharging power boundary of the supercapacitor to obtain the supercapacitor allocation power. The lithium battery reference power determination module is used to determine the power deficit based on the grid frequency regulation command and the power allocation of the supercapacitor, and to weight the power deficit according to the lifetime weighting factor to obtain the lithium battery reference power. The lifetime weighting factor is determined based on the degree of deviation between the lithium battery state of charge and the preset optimal working state of charge. The lithium battery power distribution module is used to determine the current open-circuit voltage of the lithium battery based on the state of charge of the lithium battery, and to determine the dynamic charge and discharge power boundary of the lithium battery based on the current open-circuit voltage and preset maximum allowable current and internal resistance parameters of the lithium battery. The module limits the reference power of the lithium battery according to the dynamic charge and discharge power boundary of the lithium battery to obtain the lithium battery distribution power, and outputs the supercapacitor distribution power and the lithium battery distribution power.

[0022] Thirdly, this application provides a computer device, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, it implements the supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method described in any embodiment of the first aspect.

[0023] Fourthly, this application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method described in any embodiment of the first aspect.

[0024] Compared with the prior art, this application has the following beneficial effects: Firstly, this application provides a method for power allocation in frequency regulation for supercapacitor-coupled lithium battery energy storage. This application decomposes and reconstructs the grid frequency regulation command, weights the obtained high-frequency power components according to the supercapacitor's state of charge (SOC), and determines the dynamic charge / discharge power boundary based on the supercapacitor's current terminal voltage, maximum allowable current, and equivalent series internal resistance, thus limiting the supercapacitor's reference power. Based on this, the lithium battery reference power is determined according to the remaining power deficit and the degree of deviation of the lithium battery's SOC from its optimal operating SOC, and is also limited according to the lithium battery's dynamic charge / discharge power boundary. This allows the power allocation process to simultaneously adapt to the real-time SOC and current allowable charge / discharge capabilities of both types of energy storage units, thereby reducing the likelihood of allocated power exceeding the current allowable range of the energy storage units and improving the ability of the hybrid energy storage system to continuously execute grid frequency regulation commands.

[0025] Secondly, this application provides a supercapacitor-coupled lithium battery energy storage frequency regulation power allocation system. This system, through a frequency decomposition module, a supercapacitor reference power determination module, a supercapacitor power allocation module, a lithium battery reference power determination module, and a lithium battery power allocation module, realizes frequency decomposition of grid frequency regulation commands, determination of reference powers for the two types of energy storage units, and power limiting based on dynamic charge and discharge power boundaries. This allows the data processing link for hybrid energy storage frequency regulation power allocation to be implemented through corresponding modules, facilitating modular deployment of the power allocation process and output of allocation results.

[0026] Thirdly, this application provides a computer device. This computer device executes a computer program stored in memory via a processor to perform frequency decomposition of grid frequency regulation commands, determination of reference power for supercapacitors and lithium batteries, determination of dynamic charging and discharging power boundaries, and limiting and outputting allocated power. This enables data processing and result output for hybrid energy storage frequency regulation power allocation to be completed within the computer device.

[0027] Fourthly, this application provides a computer-readable storage medium. This computer-readable storage medium is used to store a computer program for implementing a supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method, enabling the above method to be implemented through program loading and execution, facilitating its invocation and operation in a computer device. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and therefore should not be considered as a limitation on the scope of protection. For those skilled in the art, other related drawings can be obtained based on these drawings without any creative effort.

[0029] Figure 1This is a flowchart of the supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method in the embodiments of this application; Figure 2 This is a structural block diagram of the supercapacitor-coupled lithium battery energy storage frequency modulation power distribution system in the embodiments of this application; Figure 3 This is a diagram showing the internal structure of a computer device in an embodiment of this application. Detailed Implementation

[0030] Hybrid energy storage systems composed of supercapacitors and lithium batteries can leverage the differences in power response and continuous power supply capabilities between the two types of energy storage units to jointly execute grid frequency regulation commands. Existing power allocation methods typically use fixed frequency bands or fixed ratios, which fail to adequately adapt to changes in the state of charge and permissible charging and discharging power of the two types of energy storage units during operation, potentially leading to power allocation exceeding the current permissible range of the energy storage units.

[0031] Based on the above background, this application performs feedback weighting on the high-frequency power components in the grid frequency regulation command according to the state of charge of the supercapacitor, and determines the supercapacitor allocation power according to the dynamic charging and discharging power boundary of the supercapacitor; then, it determines the lithium battery reference power according to the remaining power deficit and the state of charge of the lithium battery, and determines the lithium battery allocation power according to the dynamic charging and discharging power boundary of the lithium battery, so that the power allocation result can adapt to the current operating state of the two types of energy storage units.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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 some embodiments of this application, not all 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.

[0033] Example 1 This embodiment provides a method for frequency modulation power distribution in supercapacitor-coupled lithium battery energy storage. For example... Figure 1 As shown, the method includes the following steps.

[0034] The system acquires the grid frequency regulation command, the state of charge of the supercapacitor, and the state of charge of the lithium battery. It then performs frequency decomposition and reconstruction on the grid frequency regulation command to obtain the high-frequency power component.

[0035] The grid frequency regulation command represents the frequency regulation power demand that the hybrid energy storage system needs to respond to. The state of charge (SOC) of the supercapacitor and the state of charge (SOC) of the lithium battery represent the remaining charge state of the supercapacitor and lithium battery at the current moment, respectively. The grid frequency regulation command is frequency decomposed to distinguish power components with different rates of change. The power components corresponding to the high-frequency range after decomposition are reconstructed to obtain the high-frequency power component. This high-frequency power component serves as the basis for determining the reference power of the supercapacitor, allowing the supercapacitor, with its faster response speed, to preferentially handle the faster-changing power demands in the grid frequency regulation command.

[0036] The high-frequency power components are weighted according to the feedback weighting factor determined based on the state of charge of the supercapacitor to obtain the supercapacitor reference power.

[0037] The feedback weighting factor changes with the supercapacitor's state of charge (SOC) to adjust the degree to which high-frequency power components are allocated to the supercapacitor. The supercapacitor reference power obtained after weighting the high-frequency power components retains the rapid power demand reflected by the high-frequency power components while adjusting the power load on the supercapacitor based on its current SOC, thus avoiding a fixed determination of the supercapacitor's power demand solely based on the frequency decomposition results.

[0038] The current terminal voltage of the supercapacitor is determined based on its state of charge. The dynamic charging and discharging power boundary of the supercapacitor is determined based on the current terminal voltage, the preset maximum allowable current of the supercapacitor, and the equivalent series internal resistance. The reference power of the supercapacitor is limited according to the dynamic charging and discharging power boundary of the supercapacitor to obtain the allocated power of the supercapacitor.

[0039] The current terminal voltage of a supercapacitor varies with its state of charge. The current terminal voltage, along with the maximum allowable current and equivalent series internal resistance, reflects the range of charging and discharging power that the supercapacitor can withstand under its current operating conditions. The dynamic charging and discharging power boundaries of the supercapacitor, determined based on these parameters, include both the current allowable discharge power boundary and the charging power boundary, and change dynamically with the supercapacitor's operating state.

[0040] When the supercapacitor reference power is within the range defined by the supercapacitor's dynamic charge and discharge power boundary, the supercapacitor reference power can be determined as the supercapacitor's allocated power; when the supercapacitor reference power exceeds this range, it is limited to the corresponding charging power boundary or discharging power boundary, thereby ensuring that the supercapacitor's allocated power does not exceed the supercapacitor's current allowable charge and discharge capacity.

[0041] The power deficit is determined based on the grid frequency regulation command and the power allocation of the supercapacitor. This power deficit is then weighted according to a lifetime weighting factor to obtain the reference power for the lithium battery. The lifetime weighting factor is determined based on the deviation between the lithium battery's state of charge and a preset optimal operating state of charge.

[0042] Power deficit refers to the portion of the power demand corresponding to the grid frequency regulation command that is not allocated to the supercapacitor. Using the power deficit as the input for lithium battery power allocation allows both lithium batteries and supercapacitors to share the power demand corresponding to the grid frequency regulation command.

[0043] The lifetime weighting factor is used to adjust the degree to which the power deficit is allocated to the lithium battery based on its current state of charge (SOC). When the deviation between the lithium battery's SOC and its optimal operating SOC varies, different weights are applied to the power deficit to obtain a reference power for the lithium battery that is adapted to its current SOC. This reduces the impact of directly controlling the lithium battery's charging and discharging based on the unadjusted power deficit on its operating state.

[0044] The current open-circuit voltage of the lithium battery is determined based on its state of charge. The dynamic charge and discharge power boundary of the lithium battery is determined based on the current open-circuit voltage and the preset maximum allowable current and internal resistance parameters of the lithium battery. The reference power of the lithium battery is limited according to the dynamic charge and discharge power boundary of the lithium battery to obtain the lithium battery allocation power. The supercapacitor allocation power and the lithium battery allocation power are then output.

[0045] The current open-circuit voltage of a lithium battery changes with its state of charge. The current open-circuit voltage, along with the battery's maximum allowable current and internal resistance, reflects the range of charge and discharge power the battery can withstand under current operating conditions. The dynamic charge and discharge power boundaries of a lithium battery include both the currently allowable discharge power boundary and the charging power boundary.

[0046] When the lithium battery reference power is within the range defined by the dynamic charge and discharge power boundary of the lithium battery, the lithium battery reference power can be determined as the lithium battery allocation power; when the lithium battery reference power exceeds this range, it is restricted to the corresponding charging power boundary or discharging power boundary so that the lithium battery allocation power is adapted to the current allowable charge and discharge capacity of the lithium battery.

[0047] Therefore, this embodiment sequentially completes the frequency decomposition of the grid frequency regulation command, the determination of the supercapacitor reference power, the dynamic limiting of the supercapacitor, the determination of the power deficit, the determination of the lithium battery reference power, and the dynamic limiting of the lithium battery, forming a complete processing path from the grid frequency regulation command to the power allocation of the two types of energy storage units. The power allocation of the supercapacitor and the power allocation of the lithium battery serve as the power control basis for the supercapacitor and the lithium battery, respectively, so that the power allocation result of the hybrid energy storage system simultaneously adapts to the real-time state of charge and the current allowable charge and discharge capacity of the two types of energy storage units.

[0048] Example 2 This embodiment, based on embodiment 1, provides a detailed explanation of the frequency decomposition and reconstruction process of power grid frequency regulation commands.

[0049] The power grid frequency regulation command is decomposed into multiple wavelet packets using the db4 wavelet basis to determine the frequency range corresponding to each decomposition node. The decomposition node corresponding to the target frequency range of 1 to 10 Hz is selected, and the selected decomposition node is reconstructed to obtain the high-frequency power component.

[0050] Specifically, the time-varying power grid frequency regulation command is acquired and used as the input signal for wavelet packet decomposition. The input signal is then decomposed into multiple layers using the db4 wavelet basis, resulting in multiple decomposition nodes for the power grid frequency regulation command. Different decomposition nodes correspond to different frequency ranges.

[0051] Based on the sampling frequency and wavelet packet decomposition level of the power grid frequency regulation command, the frequency range corresponding to each decomposition node is determined, and the frequency range corresponding to each decomposition node is matched with the target frequency range of 1–10 Hz. Decomposition nodes whose frequency range falls within the target frequency range of 1–10 Hz are selected, or decomposition nodes whose frequency range corresponds to the target frequency range of 1–10 Hz are selected.

[0052] Wavelet packet reconstruction is performed on the selected decomposition nodes, and the reconstructed time-domain power signal is determined as the high-frequency power component. The high-frequency power component reflects the power variation components in the target frequency range of 1 to 10 Hz in the power grid frequency regulation command, and serves as the input for subsequent determination of the supercapacitor reference power.

[0053] When selecting nodes, if the target frequency range corresponds to one decomposition node, then that decomposition node is reconstructed; if the target frequency range corresponds to multiple decomposition nodes, then each of the multiple decomposition nodes is reconstructed separately, and the reconstruction results are combined into a high-frequency power component. Thus, the high-frequency power demand suitable for supercapacitors can be extracted from the grid frequency regulation command.

[0054] Example 3 This embodiment, based on Embodiment 1, provides a detailed explanation of the process for determining the reference power of the supercapacitor and the dynamic charging and discharging power boundary of the supercapacitor.

[0055] The high-frequency power components are weighted according to a feedback weighting factor determined based on the supercapacitor's state of charge to obtain the supercapacitor reference power. The feedback weighting factor is determined by the following formula:

[0056] In the formula, For feedback weighting factors, This is the state of charge of a supercapacitor. and These are the preset upper and lower limits of the supercapacitor's state of charge.

[0057] The feedback weighting factor is calculated based on the supercapacitor's state of charge, the upper limit of the supercapacitor's state of charge, and the lower limit of the supercapacitor's state of charge. The product of the feedback weighting factor and the high-frequency power component obtained in Example 2 is determined as the supercapacitor's reference power.

[0058] The feedback weighting factor is used to characterize the impact of the supercapacitor's current state of charge on its ability to handle high-frequency power components. When the supercapacitor's state of charge changes, the feedback weighting factor changes accordingly, thereby adjusting the high-frequency power components allocated to the supercapacitor.

[0059] After obtaining the reference power of the supercapacitor, the current terminal voltage of the supercapacitor is determined based on its state of charge. The front-end voltage is determined according to the following formula:

[0060] In the formula, For supercapacitors at time The current terminal voltage, For supercapacitors at time The state of charge, and These are the maximum and minimum terminal voltages of the supercapacitor, respectively.

[0061] Based on the current terminal voltage, the preset maximum allowable current of the supercapacitor, and the equivalent series internal resistance, the supercapacitor discharge power boundary and the supercapacitor charging power boundary are determined respectively. The supercapacitor discharge power boundary is determined according to the following formula:

[0062] The charging power boundary of a supercapacitor is determined by the following formula:

[0063] In the formula, This is the maximum allowable current for the supercapacitor. This is the equivalent series internal resistance of the supercapacitor. For supercapacitors at time The discharge power boundary, For supercapacitors at time The charging power boundary.

[0064] The supercapacitor's discharge power boundary and charging power boundary together constitute the supercapacitor's dynamic charge and discharge power boundary. Since the current terminal voltage is determined based on the supercapacitor's state of charge, the supercapacitor's dynamic charge and discharge power boundary changes dynamically with the supercapacitor's state of charge.

[0065] The supercapacitor reference power is limited according to the supercapacitor's dynamic charge and discharge power boundaries. When the supercapacitor reference power is greater than the supercapacitor discharge power boundary, the supercapacitor discharge power boundary is determined as the supercapacitor allocated power; when the supercapacitor reference power is less than the supercapacitor charge power boundary, the supercapacitor charge power boundary is determined as the supercapacitor allocated power; when the supercapacitor reference power is between the supercapacitor charge power boundary and the supercapacitor discharge power boundary, the supercapacitor reference power is determined as the supercapacitor allocated power.

[0066] Through the above processing, the power distribution of the supercapacitor can be kept within the current allowable charging and discharging power range of the supercapacitor, based on adjusting the high-frequency power component according to the state of charge of the supercapacitor.

[0067] Example 4 This embodiment, based on Embodiment 1, provides a detailed explanation of the process for determining the reference power of the lithium battery and the dynamic charge / discharge power boundary of the lithium battery.

[0068] The power deficit is determined based on the grid frequency regulation command and the power allocated by the supercapacitors. Specifically, the difference between the grid frequency regulation command and the power allocated by the supercapacitors is defined as the power deficit. The power deficit represents the portion of the power demand corresponding to the grid frequency regulation command that is not met by the supercapacitors.

[0069] The power deficit is weighted using a lifetime weighting factor to obtain the reference power of the lithium battery. The lifetime weighting factor is determined based on the deviation between the lithium battery's state of charge and a preset optimal operating state of charge, and is calculated according to the following formula:

[0070] In the formula, Lifetime weighting factor This is the state of charge of the lithium battery. This is the preset optimal state of charge. This is the preset standard deviation.

[0071] The product of the lifetime weighting factor and the power deficit is determined as the lithium battery reference power. The lifetime weighting factor varies with the deviation between the lithium battery's state of charge (SOC) and its optimal operating SOC, and is used to adjust the degree to which the lithium battery bears the power deficit. When the lithium battery's SOC is close to its optimal operating SOC, the lifetime weighting factor is relatively large; when the lithium battery's SOC deviates from its optimal operating SOC, the lifetime weighting factor decreases accordingly, thereby adjusting the lithium battery reference power based on the current SOC of the lithium battery.

[0072] After obtaining the reference power of the lithium battery, the current open-circuit voltage of the lithium battery is determined based on its state of charge. The current open-circuit voltage is determined according to the following formula:

[0073] In the formula, For lithium batteries at all times The current open-circuit voltage, For lithium batteries at all times The state of charge, and These are the maximum and minimum open-circuit voltages of the lithium battery, respectively.

[0074] The internal resistance parameters of a lithium battery include ohmic internal resistance and charge transfer internal resistance. Based on the current open-circuit voltage of the lithium battery, the preset maximum allowable current, the ohmic internal resistance, and the charge transfer internal resistance, the discharge power boundary and the charging power boundary of the lithium battery are determined respectively. The discharge power boundary is determined according to the following formula:

[0075] The charging power boundary of a lithium battery is determined by the following formula:

[0076] In the formula, This is the maximum allowable current for lithium batteries. For ohmic internal resistance, For charge transfer internal resistance, For lithium batteries at all times The discharge power boundary, For lithium batteries at all times The charging power boundary.

[0077] The lithium battery discharge power boundary and the lithium battery charging power boundary together constitute the dynamic charge and discharge power boundary of the lithium battery. Since the current open-circuit voltage is determined based on the lithium battery's state of charge, the dynamic charge and discharge power boundary of the lithium battery changes dynamically with the lithium battery's state of charge.

[0078] The reference power of the lithium battery is limited according to the dynamic charge and discharge power boundaries of the lithium battery. When the reference power of the lithium battery is greater than the discharge power boundary, the discharge power boundary is determined as the allocated power of the lithium battery; when the reference power of the lithium battery is less than the charging power boundary, the charging power boundary is determined as the allocated power of the lithium battery; when the reference power of the lithium battery is between the charging power boundary and the discharge power boundary, the reference power is determined as the allocated power of the lithium battery.

[0079] The supercapacitor allocation power determined in Example 3 and the lithium battery allocation power determined in this example are used as the basis for power control of the supercapacitor and lithium battery, respectively. Through the above processing, the reference power of the lithium battery can be determined based on the remaining power deficit and the state of charge of the lithium battery, and the lithium battery allocation power can be kept within the current allowable charge and discharge power range of the lithium battery.

[0080] Example 5 This embodiment, based on embodiment 1, provides a detailed explanation of the process of proportional-integral closed-loop correction based on power grid frequency deviation.

[0081] After limiting the reference power of the lithium battery according to the dynamic charging and discharging power boundary of the lithium battery to obtain the lithium battery power allocation, the actual frequency of the power grid is obtained, and the frequency deviation is determined based on the difference between the actual frequency of the power grid and the rated frequency.

[0082] The proportional-integral (PI) correction amount is determined based on the frequency deviation. This PI correction amount is used to correct the sum of the power allocated by the supercapacitor and the power allocated by the lithium battery. The PI correction amount is calculated according to the following formula:

[0083] In the formula, For a moment The proportional integral correction amount For a moment frequency deviation, This is the proportionality coefficient. The integral coefficient is... The starting time of integration, This is the time variable for integration.

[0084] The proportional term determines the corresponding power correction based on the current frequency deviation, and the integral term determines the corresponding power correction based on the cumulative frequency deviation from the start of integration to the current time. The sum of the two constitutes the proportional-integral correction.

[0085] The total feedforward power is determined based on the allocated power of the supercapacitor and the allocated power of the lithium battery. Specifically, the sum of the allocated power of the supercapacitor and the allocated power of the lithium battery is determined as the total feedforward power. The total feedforward power represents the initial power control target determined based on the grid frequency regulation command, the state of charge of the supercapacitor, the state of charge of the lithium battery, and the dynamic charge and discharge power boundaries of the two types of energy storage units.

[0086] The sum of the total feedforward power and the proportional-integral correction is determined as the total correction power target, and this total correction power target is output as the execution command for the power conversion system. The power conversion system controls the supercapacitor and lithium battery to charge or discharge according to this execution command.

[0087] During frequency regulation, the actual grid frequency is continuously acquired, and the frequency deviation and proportional-integral (PI) correction are updated. As the actual grid frequency changes, the total correction power target is adjusted accordingly, thus forming a closed-loop correction process based on grid frequency deviation on the basis of feedforward power allocation.

[0088] In this embodiment, the power distribution by the supercapacitor and the power distribution by the lithium battery constitute the feedforward control quantity, and the proportional-integral correction quantity is formed according to the frequency deviation between the actual frequency of the power grid and the rated frequency, so that the execution command output to the power conversion system can be corrected according to the change of the actual frequency of the power grid.

[0089] Example 6 Based on Example 1, this embodiment takes a 10 MW hybrid energy storage frequency regulation system applied to a new energy power plant as an example to illustrate the parameter settings, operation process and implementation effect of the method of this application.

[0090] The hybrid energy storage frequency regulation system in this embodiment includes a lithium battery energy storage unit, a supercapacitor energy storage unit, a control system, and a power conversion system.

[0091] The lithium-ion battery energy storage unit has a rated power of 10 MW, a rated capacity of 10 MWh, and a charge / discharge rate of 1 C, using lithium iron phosphate batteries. The battery pack has a rated voltage of 1500 V and a rated capacity of 6667 Ah. The maximum open-circuit voltage of a single lithium-ion battery cell is 3.65 V, the minimum open-circuit voltage is 2.5 V, the ohmic internal resistance is 1 mΩ, the charge transfer internal resistance is 2 mΩ, and the maximum charge / discharge rate is 1 C. These individual lithium-ion battery parameters are used for device selection and pack design of the lithium-ion battery energy storage unit. When calculating the dynamic charge / discharge power boundary of the lithium-ion battery energy storage unit, the individual lithium-ion battery parameters are converted into equivalent parameters on the lithium-ion battery energy storage unit side based on the series and parallel connection relationship of the battery pack.

[0092] The supercapacitor energy storage unit has a rated power of 2 MW, a rated capacity of 0.05 MWh, a rated voltage of 1500 V, and a maximum charge / discharge current of 1900 A. The supercapacitor energy storage unit consists of multiple individual supercapacitors, and their state of charge (SOC) is determined based on the terminal voltage of the supercapacitor energy storage unit. The aforementioned individual supercapacitor parameters are used for device selection and group design of the supercapacitor energy storage unit; when calculating the dynamic charge / discharge power boundary of the supercapacitor energy storage unit, the individual supercapacitor parameters are converted into equivalent parameters on the supercapacitor energy storage unit side based on the series and parallel connection relationship of the supercapacitors. Upper limit of supercapacitor SOC. The value is 0.9, which is the lower limit of the state of charge of a supercapacitor. It is 0.1.

[0093] The main control unit of the control system uses a TI TMS320F28335 digital signal processor (DSP) with a control cycle of 10 ms and a sampling frequency of 100 Hz. The control system's data acquisition unit includes voltage sensors, current sensors, and a frequency acquisition module, which acquire the actual grid frequency, the terminal voltage and charging / discharging current of the supercapacitor, and the voltage and current of the lithium battery, respectively. The control system also obtains the state of charge of the lithium battery through a battery management system (BMS). The power conversion system uses a power conversion system (PCS) and controls the charging or discharging of the supercapacitor and lithium battery energy storage units according to the power commands output by the main control unit.

[0094] Within each 10 ms control cycle, real-time signal acquisition and preprocessing are performed first.

[0095] The actual grid frequency at the grid connection point is acquired through a frequency acquisition module, and the frequency deviation is determined based on the difference between the actual grid frequency and the 50Hz rated frequency. Real-time terminal voltage and charging / discharging current of the supercapacitor are acquired through voltage and current sensors, and the supercapacitor's state of charge (SOC) is determined based on the acquisition results. Real-time SOC, individual cell voltage, and current data of the lithium battery are acquired through a battery management system. Simultaneously, real-time automatic generation control (AGC) frequency regulation commands issued by the power station dispatch center are received, and the grid frequency regulation commands are pre-processed by limiting and filtering to remove glitches and interference.

[0096] After signal acquisition and preprocessing, the frequency regulation command of the power grid is decomposed and reconstructed.

[0097] In this embodiment, the sampling frequency is set to 100 Hz, and wavelet packet decomposition is performed using the db4 wavelet basis, with the minimum decomposition level being [number missing]. Setting it to 3 will increase the maximum number of decomposition levels. Set to 4, extract the wavelet packet coefficients of the high-frequency band corresponding to the target frequency range of 1 to 10 Hz, and reconstruct the corresponding decomposition nodes to obtain the high-frequency power components.

[0098] The upper limit of the supercapacitor's state of charge is set to 0.9, and the lower limit of the supercapacitor's state of charge is set to 0.1. The feedback weighting factor is determined based on the real-time acquired supercapacitor state of charge, and the high-frequency power components are weighted according to the method described in Example 3 to obtain the supercapacitor reference power.

[0099] The current terminal voltage of the supercapacitor energy storage unit is determined based on its state of charge (SOC). Then, based on the current terminal voltage, the maximum allowable current of the supercapacitor unit, and the equivalent series resistance of the grouped supercapacitors, the dynamic charge / discharge power boundary of the supercapacitor energy storage unit within the current control cycle is determined. The equivalent series resistance of the grouped supercapacitors is determined based on the equivalent series resistance of each individual supercapacitor and the series-parallel connection relationship of the supercapacitor energy storage units. The supercapacitor reference power is limited according to this dynamic charge / discharge power boundary to obtain the allocated power. This allocated power is output to the energy storage converter corresponding to the supercapacitor energy storage unit and used for subsequent power deficit calculations.

[0100] The power deficit is determined based on the difference between the grid frequency regulation command and the power allocated by the supercapacitor. This embodiment utilizes the optimal state of charge (SOC) of the lithium battery. Set to 0.5, preset standard deviation The value is set to 0.2. The lifetime weighting factor is determined based on the real-time acquired state of charge of the lithium battery, and the power deficit is weighted according to the lifetime weighting factor to obtain the reference power of the lithium battery.

[0101] The current open-circuit voltage of the lithium-ion battery energy storage unit is determined based on its state of charge (SOC). Then, based on the current SOC, the maximum allowable current of the lithium-ion battery energy storage unit, and the equivalent internal resistance parameters of the battery pack, the dynamic charge / discharge power boundary of the lithium-ion battery energy storage unit within the current control cycle is determined. The equivalent internal resistance parameters of the battery pack are determined based on the ohmic internal resistance and charge transfer internal resistance of the individual lithium-ion battery cells, as well as the series-parallel relationship of the battery pack. The reference power of the lithium-ion battery is limited according to this dynamic charge / discharge power boundary to obtain the allocated power. This allocated power is then output to the energy storage converter corresponding to the lithium-ion battery energy storage unit.

[0102] After obtaining the power allocation from the supercapacitor and the lithium battery, closed-loop power correction is performed. This embodiment targets a 10 MW hybrid energy storage frequency regulation system, where the proportional coefficient... Set to 10000 W / Hz, and adjust the integration coefficient. Set to 1000W / (Hz·s). Determine the proportional-integral correction amount based on the frequency deviation between the actual grid frequency and the 50 Hz rated frequency; take the sum of the supercapacitor distribution power and the lithium battery distribution power as the total feedforward power, and determine the total correction power target as the sum of the total feedforward power and the proportional-integral correction amount.

[0103] The control system outputs the total corrected power target as an execution command to the power conversion system. The power conversion system controls the charging or discharging of the supercapacitor energy storage unit and the lithium battery energy storage unit according to the execution command, and uses the operating data collected in this control cycle for power allocation and closed-loop correction in the next control cycle.

[0104] Under the operating conditions of the aforementioned engineering example, the state of charge of the supercapacitor was maintained at 0.2–0.8, with no overcharging or over-discharging phenomena; the state of charge of the lithium battery was concentrated at 0.4–0.6, reducing deep charging and discharging of the lithium battery and cycling in the edge range of the state of charge, thus extending the cycle life of the lithium battery by more than 35%; the steady-state error of the grid frequency regulation was no greater than ±0.02 Hz, and the pass rate of automatic generation control frequency regulation was no less than 99%.

[0105] Example 7 In one embodiment of this application, such as Figure 2 As shown, a supercapacitor-coupled lithium battery energy storage frequency regulation power distribution system is provided. This system is used to execute the aforementioned supercapacitor-coupled lithium battery energy storage frequency regulation power distribution method.

[0106] The frequency decomposition module is used to acquire the grid frequency regulation command, the supercapacitor's state of charge (SOC), and the lithium battery's SOC. It performs wavelet packet decomposition on the grid frequency regulation command, determines the target decomposition level based on the target frequency range, and reconstructs the signal using the wavelet packet coefficients corresponding to the target decomposition level to obtain the high-frequency power component. The frequency decomposition module can communicate with the power station dispatch system, voltage sensors, current sensors, and the battery management system. The grid frequency regulation command can be issued by the power station dispatch system; the supercapacitor's SOC can be determined based on its terminal voltage and charging / discharging current; and the lithium battery's SOC can be obtained through the battery management system. The high-frequency power component represents the high-frequency fluctuation portion of the grid frequency regulation command that is preferentially handled by the supercapacitor.

[0107] The supercapacitor reference power determination module is used to determine the feedback weighting factor based on the supercapacitor's state of charge, and to weight the high-frequency power components according to the feedback weighting factor to obtain the supercapacitor reference power.

[0108] The supercapacitor power allocation module determines the current terminal voltage of the supercapacitor based on its state of charge (SBC). It then determines the dynamic charge / discharge power boundary of the supercapacitor based on the current terminal voltage, the maximum allowable current, and the equivalent series resistance. The module limits the reference power of the supercapacitor according to this dynamic charge / discharge power boundary to obtain the allocated power. The feedback weighting factor varies with the supercapacitor's SBC. When the supercapacitor's SBC is within a preset intermediate operating range, the feedback weighting factor is relatively large, allowing the supercapacitor to handle a relatively large portion of the high-frequency power components. When the supercapacitor's SBC approaches the upper or lower limit of its SBC, the feedback weighting factor decreases accordingly to reduce the high-frequency power components handled by the supercapacitor. The dynamic charge / discharge power boundary dynamically changes with the current terminal voltage corresponding to the supercapacitor's SBC, thus constraining the allocated power.

[0109] The lithium battery reference power determination module is used to determine the power deficit based on the grid frequency regulation command and the power allocation of the supercapacitor, determine the lifetime weighting factor based on the deviation between the lithium battery state of charge and the preset optimal working state of charge, and weight the power deficit according to the lifetime weighting factor to obtain the lithium battery reference power.

[0110] The lithium battery power allocation module is also used to determine the current open-circuit voltage of the lithium battery based on its state of charge (SOC), and to determine the dynamic charge / discharge power boundary of the lithium battery based on the current open-circuit voltage, the maximum allowable current of the lithium battery, and its internal resistance parameters. The reference power of the lithium battery is then limited according to the dynamic charge / discharge power boundary to obtain the allocated power. The closer the lithium battery's SOC is to the preset optimal operating SOC, the larger the lifetime weighting factor; the further the lithium battery's SOC deviates from the preset optimal operating SOC, the smaller the lifetime weighting factor. This allows for adjustment of the degree to which the lithium battery bears the power deficit based on the current SOC.

[0111] In some embodiments, the system further includes a closed-loop correction module. The closed-loop correction module is used to determine the frequency deviation based on the actual grid frequency and the rated frequency, determine the proportional-integral correction amount based on the frequency deviation, and determine the total correction power target based on the power allocated by the supercapacitor, the power allocated by the lithium battery, and the proportional-integral correction amount. The total correction power target is output to the power conversion system, which controls the charging or discharging of the supercapacitor energy storage unit and the lithium battery energy storage unit.

[0112] Within a control cycle, the frequency decomposition module acquires the grid frequency regulation command, the supercapacitor's state of charge (SOC), and the lithium battery's SOC, and sends the obtained high-frequency power component to the supercapacitor reference power determination module. The supercapacitor reference power determination module sends the obtained supercapacitor reference power to the supercapacitor power allocation module, which in turn sends the obtained supercapacitor allocated power to the lithium battery reference power determination module. The lithium battery reference power determination module obtains the lithium battery reference power based on the grid frequency regulation command, the supercapacitor allocated power, and the lithium battery SOC, and sends this reference power to the lithium battery power allocation module. The lithium battery power allocation module obtains the lithium battery allocated power and outputs both the supercapacitor allocated power and the lithium battery allocated power. When the system also includes a closed-loop correction module, the supercapacitor allocated power and the lithium battery allocated power are also sent to the closed-loop correction module, which generates a total corrected power target based on the two allocated power values ​​and the frequency deviation.

[0113] After the power conversion system executes the overall corrected power target, the frequency decomposition module continues to acquire the grid frequency regulation command, the supercapacitor's state of charge, and the lithium battery's state of charge. When the system includes a closed-loop correction module, this module continues to acquire the actual grid frequency. This data is used for power allocation and closed-loop correction in the next control cycle, thus forming a continuous closed-loop control process.

[0114] In some embodiments, the above modules can be implemented by programs running in a digital signal processor, programmable logic controller, or industrial controller, or they can be configured as corresponding hardware circuits according to the processing functions performed by each module. The division of modules is used to describe the corresponding data processing functions and does not constitute a limitation on the physical configuration of the modules.

[0115] Example 8 Figure 3 An internal structural diagram of a computer device is shown in one embodiment. This computer device may specifically be a terminal or a server. Figure 3 As shown, the computer device includes a processor, memory, network interface, display, camera, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements the aforementioned supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method. The display can be a liquid crystal display (LCD) or an e-ink display. The input device can be a touch layer covering the display, buttons, a trackball, or a touchpad on the computer device's casing, or an external keyboard, touchpad, or mouse.

[0116] As will be understood by those skilled in the art, computer equipment Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computing devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0117] In one embodiment, a computer device is provided, including a processor and a computer-readable storage medium, wherein the processor performs the steps of the above method when executing a computer program.

[0118] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0119] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0120] The embodiments described above are merely preferred embodiments of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A method for frequency modulation power distribution in supercapacitor-coupled lithium battery energy storage, characterized in that, include: The grid frequency regulation command, the state of charge of the supercapacitor, and the state of charge of the lithium battery are obtained. The grid frequency regulation command is decomposed and reconstructed to obtain the high-frequency power component. The feedback weighting factor is determined based on the state of charge of the supercapacitor; the high-frequency power components are weighted according to the feedback weighting factor to obtain the supercapacitor reference power; The current terminal voltage of the supercapacitor is determined based on the state of charge of the supercapacitor, and the dynamic charging and discharging power boundary of the supercapacitor is determined based on the current terminal voltage, the preset maximum allowable current of the supercapacitor, and the equivalent series internal resistance. The reference power of the supercapacitor is limited according to the dynamic charging and discharging power boundary of the supercapacitor to obtain the allocated power of the supercapacitor. The power deficit is determined according to the power grid frequency regulation command and the power allocation of the supercapacitor. The power deficit is then weighted according to the lifetime weighting factor to obtain the lithium battery reference power. The lifetime weighting factor is determined based on the degree of deviation between the lithium battery state of charge and the preset optimal working state of charge. The current open-circuit voltage of the lithium battery is determined based on the state of charge of the lithium battery. The dynamic charge and discharge power boundary of the lithium battery is determined based on the current open-circuit voltage and the preset maximum allowable current and internal resistance parameters of the lithium battery. The reference power of the lithium battery is limited according to the dynamic charge and discharge power boundary of the lithium battery to obtain the lithium battery allocation power. The supercapacitor allocation power and the lithium battery allocation power are then output.

2. The supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method according to claim 1, characterized in that, The frequency regulation command of the power grid is decomposed and reconstructed to obtain high-frequency power components, including: The power grid frequency regulation command is decomposed into multiple wavelet packets using the db4 wavelet basis to determine the frequency range corresponding to each decomposition node. The decomposition node corresponding to the target frequency range of 1 to 10 Hz is selected, and the selected decomposition node is reconstructed to obtain the high-frequency power component.

3. The supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method according to claim 1, characterized in that, The high-frequency power components are weighted according to a feedback weighting factor determined based on the supercapacitor's state of charge to obtain the supercapacitor reference power, including: The feedback weighting factor is determined according to the following formula: In the formula, The feedback weighting factor is... This refers to the state of charge of the supercapacitor. and These are the preset upper and lower limits of the supercapacitor's state of charge; The product of the feedback weighting factor and the high-frequency power component is determined as the reference power of the supercapacitor.

4. The supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method according to claim 1, characterized in that, The current terminal voltage of the supercapacitor is determined based on its state of charge, and the dynamic charging and discharging power boundary of the supercapacitor is determined based on the current terminal voltage, the preset maximum allowable current of the supercapacitor, and the equivalent series internal resistance, including: The current terminal voltage is determined according to the following formula: The discharge power boundary of a supercapacitor is determined according to the following formula: The charging power boundary of a supercapacitor is determined according to the following formula: In the formula, The current terminal voltage, This refers to the state of charge of the supercapacitor. and These are the maximum and minimum terminal voltages of the supercapacitor, respectively. This is the maximum allowable current of the supercapacitor. The equivalent series internal resistance is... and These are the supercapacitor discharge power boundary and the supercapacitor charging power boundary, respectively.

5. The supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method according to claim 1, characterized in that, The power deficit is weighted according to a lifetime weighting factor to obtain the lithium battery reference power. The lifetime weighting factor is determined based on the deviation between the lithium battery's state of charge and a preset optimal operating state of charge, including: The lifetime weighting factor is determined according to the following formula: In the formula, The lifetime weighting factor is... The state of charge of the lithium battery. This is the optimal state of charge. The standard deviation is the preset value. The product of the lifetime weighting factor and the power deficit is determined as the reference power of the lithium battery.

6. The supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method according to claim 1, characterized in that, The internal resistance parameters include ohmic internal resistance and charge transfer internal resistance; The current open-circuit voltage of the lithium battery is determined based on the state of charge of the lithium battery, and the dynamic charge / discharge power boundary of the lithium battery is determined based on the current open-circuit voltage and preset maximum allowable current and internal resistance parameters of the lithium battery, including: The current open-circuit voltage is determined according to the following formula: The lithium battery discharge power boundary and lithium battery charging power boundary are determined according to the following formulas: In the formula, The current open-circuit voltage, The state of charge of the lithium battery. and These are the maximum and minimum open-circuit voltages of the lithium battery, respectively. This is the maximum allowable current of the lithium battery. The internal resistance is ohmic. The charge transfer internal resistance, and These are the lithium battery discharge power boundary and the lithium battery charging power boundary, respectively.

7. The supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method according to claim 1, characterized in that, The lithium battery reference power is limited according to the dynamic charge and discharge power boundary of the lithium battery to obtain the lithium battery power allocation, and then the following steps are included: Obtain the actual grid frequency, and based on the frequency deviation between the actual grid frequency and the rated frequency, determine the proportional-integral correction amount used to correct the sum of the supercapacitor's allocated power and the lithium battery's allocated power according to the following formula: The total feedforward power is determined based on the supercapacitor power allocation and the lithium battery power allocation. The sum of the total feedforward power and the proportional-integral correction amount is determined as the total correction power target. The total correction power target is then output as the execution command of the power conversion system. In the formula, This is the proportional-integral correction amount. The frequency deviation is... and These are the proportional coefficient and the integral coefficient, respectively. The starting time of integration, This is the time variable for integration.

8. A supercapacitor-coupled lithium battery energy storage frequency regulation power distribution system, characterized in that, include: The frequency decomposition module is used to acquire the power grid frequency regulation command, the state of charge of the supercapacitor and the state of charge of the lithium battery, and to perform frequency decomposition and reconstruction on the power grid frequency regulation command to obtain high-frequency power components. A supercapacitor reference power determination module is used to determine a feedback weighting factor based on the supercapacitor's state of charge; and to weight the high-frequency power components according to the feedback weighting factor to obtain the supercapacitor reference power. The supercapacitor power allocation module is used to determine the current terminal voltage of the supercapacitor based on the state of charge of the supercapacitor, and to determine the dynamic charging and discharging power boundary of the supercapacitor based on the current terminal voltage and the preset maximum allowable current and equivalent series internal resistance of the supercapacitor. The supercapacitor reference power is limited according to the dynamic charging and discharging power boundary of the supercapacitor to obtain the supercapacitor allocation power. The lithium battery reference power determination module is used to determine the power deficit based on the grid frequency regulation command and the power allocation of the supercapacitor, and to weight the power deficit according to the lifetime weighting factor to obtain the lithium battery reference power; the lifetime weighting factor is determined based on the degree of deviation between the lithium battery state of charge and the preset optimal working state of charge. The lithium battery power distribution module is used to determine the current open-circuit voltage of the lithium battery based on the state of charge of the lithium battery, and to determine the dynamic charge and discharge power boundary of the lithium battery based on the current open-circuit voltage and preset maximum allowable current and internal resistance parameters of the lithium battery. The module limits the reference power of the lithium battery according to the dynamic charge and discharge power boundary of the lithium battery to obtain the lithium battery distribution power, and outputs the supercapacitor distribution power and the lithium battery distribution power.

9. A computer device, characterized in that, include: Processor and computer-readable storage media; A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program adapted to be loaded by a processor and executed as described in any one of claims 1 to 7, the supercapacitor-coupled lithium battery energy storage frequency modulation power distribution method.

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