A primary frequency modulation control method and system for a hybrid energy storage power station

Abstract

The application discloses a primary frequency modulation control method and system of a hybrid energy storage power station, relates to the technical field of power grid frequency modulation, and comprises the following steps: when a current frequency deviation of the hybrid energy storage power station is not in a preset frequency modulation dead zone range and the current frequency deviation is greater than zero, determining a first current frequency modulation control strategy based on the charging priority of two groups of energy storage components, the current frequency deviation, the preset frequency modulation dead zone range and the current state of charge corresponding to the two groups of energy storage components; if the current frequency deviation is less than or equal to zero, determining a second current frequency modulation control strategy; the second current frequency modulation control strategy is used for realizing frequency modulation control meeting the discharge demand; when the current frequency deviation is in the preset frequency modulation dead zone range, determining a third current frequency modulation control strategy; the third current frequency modulation control strategy is used for realizing self-recovery frequency modulation control of any energy storage component. The application can scientifically and efficiently solve the frequency stability problem of power distribution of the hybrid energy storage and primary frequency modulation of the power grid.

Description

Technical Field

[0001] This invention relates to the field of power grid frequency regulation technology, and in particular to a primary frequency regulation control method and system for a hybrid energy storage power station. Background Technology

[0002] With the continuous increase in the installed capacity of renewable energy sources such as wind power and photovoltaics, the penetration rate of wind power is rising year by year. The intermittency, volatility, and unpredictability of its output pose challenges to the safe and stable operation of the power grid. Maintaining frequency stability is one of the key factors for the safe and stable operation of the power grid. Energy storage systems, as a key technology in building new power systems, can fully utilize the complementary technical characteristics of different types of energy storage, possessing outstanding advantages such as flexible control and rapid response. They are currently a superior frequency regulation power source and can effectively improve the problems brought about by renewable energy grid integration. Therefore, research can be conducted on primary frequency regulation control strategies for hybrid energy storage power stations, taking into account the frequency regulation characteristics of different types of energy storage and the remaining frequency regulation capacity.

[0003] Currently, in terms of single energy storage operation control strategies, the relevant research on energy storage participation in the primary frequency regulation operation control of the power grid is mainly divided into two types: (1) virtual droop control method that imitates the droop characteristics of the unit; virtual droop control mainly includes fixed K method and variable K method (K is the virtual droop coefficient). (2) virtual inertial control method to suppress the deterioration of the initial frequency.

[0004] In terms of coordinated control strategies for hybrid energy storage, in order to enable energy storage power stations to simultaneously possess large capacity and high power performance, energy-type energy storage media and power-type energy storage media are usually combined into a hybrid energy storage system. Control strategies can be divided into two main categories: (1) Unoptimized algorithms, such as those based on filtering (low-pass / high-pass filters) and droop control. Unoptimized algorithm control strategies do not rely on optimization design, but they have acceptable performance and can be implemented in real-time applications. Among them, the commonly used filtering-based control strategy is to pass the power demand signal through a first-order low-pass filter, so that the power-type energy storage responds to the high-frequency components in the power command, and the energy-type energy storage responds to the low-frequency components in the power command, thereby reducing the number of charge and discharge cycles of the lithium battery and improving its lifespan. In the droop control strategy, the droop coefficient of the power-type energy storage system is usually set to be greater than that of the energy-type energy storage system, or the adjustment dead zone of the power-type energy storage system is within the adjustment dead zone of the energy-type energy storage system, so that the power-type energy storage takes priority and quickly provides more power to enable the system to quickly recover stability. (2) Optimization involving power allocation is usually based on the predicted power demand signals of the day and day for global optimization. Existing methods mainly aim to optimize the system lifetime index. Commonly used methods include particle swarm optimization, genetic algorithm, and mixed integer linear programming.

[0005] However, the aforementioned control strategies all have corresponding technical drawbacks in practical applications. For example: 1) Optimization-based power allocation strategies suffer from complex solution processes, large computational costs, and numerous constraints, making it difficult to quickly and easily determine the power of different types of energy storage devices participating in frequency regulation based on the primary frequency regulation requirements of the power grid. 2) Using only a single droop control strategy, which determines the action sequence by setting the droop coefficient of different types of energy storage and the frequency regulation dead zone, fails to consider the coordination of power output from different types of energy storage systems, thus failing to maximize the advantages of hybrid power plants. 3) Studying only the power allocation between different types of energy storage during frequency regulation without considering the self-recovery of the energy storage's state of charge to the optimal position within the frequency regulation dead zone will have a certain impact on the lifespan of the energy storage and subsequent frequency regulation performance. Summary of the Invention

[0006] The purpose of this invention is to provide a primary frequency regulation control method and system for hybrid energy storage power stations, which can scientifically and efficiently solve the problems of power distribution of hybrid energy storage and frequency stability during primary frequency regulation of the power grid.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] A primary frequency regulation control method for a hybrid energy storage power station, applied to a hybrid energy storage power station comprising two sets of energy storage components, the method comprising:

[0009] Obtain the current frequency deviation of the hybrid energy storage power station and the current state of charge of each of the two sets of energy storage components;

[0010] When the current frequency deviation is not within the preset frequency tuning dead zone range, determine whether the current frequency deviation is greater than zero;

[0011] If the current frequency deviation is greater than zero, the charging priority of the two sets of energy storage components is determined based on their respective current states of charge. Based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone, and the respective current states of charge of the two sets of energy storage components, a first current frequency regulation control strategy for the hybrid energy storage power station is determined. The first current frequency regulation control strategy is used to achieve frequency regulation control that meets charging requirements.

[0012] If the current frequency deviation is less than or equal to zero, the discharge priority of the two sets of energy storage components is determined based on their respective current states of charge. A second current frequency regulation control strategy for the hybrid energy storage power station is determined based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone, and the respective current states of charge of the two sets of energy storage components. This second current frequency regulation control strategy is used to achieve frequency regulation control that meets the discharge requirements.

[0013] When the current frequency deviation is within the preset frequency regulation dead zone range, a third current frequency regulation control strategy for the hybrid energy storage power station is determined based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components; the third current frequency regulation control strategy is used to realize the self-recovering frequency regulation control of any energy storage component.

[0014] Optionally, the two sets of energy storage components are a lithium battery and a supercapacitor energy storage system, respectively;

[0015] Based on the current state of charge of each of the two sets of energy storage components, the charging priority of the two sets of energy storage components is determined, specifically including:

[0016] When the current state of charge of the lithium battery is higher than or equal to the current state of charge of the supercapacitor energy storage system, the charging priority is: the supercapacitor energy storage system is charged first, and the lithium battery is charged to meet the charging requirements.

[0017] When the current state of charge of the lithium battery is lower than the current state of charge of the supercapacitor energy storage system, the charging priority is: the lithium battery is charged first, and the supercapacitor energy storage system is charged to meet the charging requirements.

[0018] Optionally, based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge corresponding to each of the two sets of energy storage components, a first current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including:

[0019] Based on virtual droop control, the first current frequency regulation action of the hybrid energy storage power station is calculated according to the current frequency deviation and the preset frequency regulation dead zone range;

[0020] Calculate the maximum charging power of the lithium battery based on its current state of charge; calculate the maximum charging power of the supercapacitor energy storage system based on its current state of charge.

[0021] Based on the charging priority, the maximum charging power of the lithium battery, the maximum charging power of the supercapacitor energy storage system, and the first current frequency regulation action of the hybrid energy storage power station, the first current frequency regulation control strategy of the hybrid energy storage power station is determined.

[0022] Optionally, the two sets of energy storage components are a lithium battery and a supercapacitor energy storage system, respectively;

[0023] Based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components, a second current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including:

[0024] Based on virtual droop control, the second current primary frequency regulation action of the hybrid energy storage power station is calculated according to the current frequency deviation and the preset frequency regulation dead zone range;

[0025] Calculate the maximum discharge power of the lithium battery based on its current state of charge; calculate the maximum discharge power of the supercapacitor energy storage system based on its current state of charge.

[0026] Based on the discharge priority, the maximum discharge power of the lithium battery, the maximum discharge power of the supercapacitor energy storage system, and the second current frequency regulation action of the hybrid energy storage power station, the second current frequency regulation control strategy of the hybrid energy storage power station is determined.

[0027] Optionally, the two sets of energy storage components are a lithium battery and a supercapacitor energy storage system, respectively;

[0028] Based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components, a third current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including:

[0029] Based on the current state of charge of the lithium battery, calculate the self-recovery charging power requirement and the self-recovery discharging power requirement of the lithium battery; based on the current state of charge of the supercapacitor energy storage system, calculate the self-recovery charging power requirement and the self-recovery discharging power requirement of the supercapacitor energy storage system.

[0030] Based on the current frequency deviation and the preset frequency tuning dead zone range, the charging power constraints and discharging power constraints of the lithium battery and the charging power constraints and discharging power constraints of the supercapacitor energy storage system are calculated respectively.

[0031] The actual self-recovery power of the lithium battery is determined based on its current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirement, and self-recovery discharging power requirement; the actual self-recovery power of the supercapacitor energy storage system is determined based on its current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirement, and self-recovery discharging power requirement.

[0032] Optionally, the actual self-recovery power of the lithium battery is determined based on its current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirement, and self-recovery discharging power requirement. Specifically, this includes:

[0033] If the current state of charge of the lithium battery is less than the lower state of charge value of the lithium battery, then the actual recovery power of the lithium battery is determined according to the self-recovery charging power requirement of the lithium battery and the charging power constraint.

[0034] If the current state of charge of the lithium battery is greater than the higher state of charge value of the lithium battery, then the actual recovery power of the lithium battery is determined according to the self-recovery discharge demand power of the lithium battery and the discharge power constraint.

[0035] If the current state of charge of the lithium battery is greater than or equal to the lower state of charge value of the lithium battery, and less than or equal to the higher state of charge value of the lithium battery, then the actual recovery power of the lithium battery is 0; wherein the higher state of charge value and the lower state of charge value of the lithium battery are both preset values.

[0036] To achieve the above objectives, the present invention also provides the following technical solutions:

[0037] A primary frequency regulation control system for a hybrid energy storage power station, applied to a hybrid energy storage power station comprising two sets of energy storage components, the system comprising:

[0038] The data acquisition module is used to acquire the current frequency deviation of the hybrid energy storage power station and the current state of charge of each of the two sets of energy storage components.

[0039] The frequency deviation judgment module is used to determine whether the current frequency deviation is greater than zero when the current frequency deviation is not within the preset frequency tuning dead zone range.

[0040] The first frequency regulation control module is used to determine the charging priority of the two sets of energy storage components based on their respective current states of charge when the current frequency deviation is greater than zero; and to determine a first current frequency regulation control strategy for the hybrid energy storage power station based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone range, and the respective current states of charge of the two sets of energy storage components; the first current frequency regulation control strategy is used to achieve frequency regulation control that meets charging requirements.

[0041] The second frequency regulation control module is used to determine the discharge priority of the two sets of energy storage components based on their respective current states of charge when the current frequency deviation is less than or equal to zero; and to determine a second current frequency regulation control strategy for the hybrid energy storage power station based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone range, and the respective current states of charge of the two sets of energy storage components; the second current frequency regulation control strategy is used to achieve frequency regulation control that meets the discharge requirements.

[0042] The third frequency regulation control module is used to determine a third current frequency regulation control strategy for the hybrid energy storage power station based on the current frequency deviation, the preset frequency regulation dead zone, and the current state of charge of each of the two sets of energy storage components when the current frequency deviation is within a preset frequency regulation dead zone range. The third current frequency regulation control strategy is used to achieve self-recovering frequency regulation control for any energy storage component.

[0043] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0044] This invention discloses a primary frequency regulation control method and system for a hybrid energy storage power station. Based on the current frequency deviation of the hybrid energy storage power station and the current state of charge of each of the two sets of energy storage components, a reasonable setting of the frequency regulation dead zone of the hybrid energy storage power station is achieved by pre-setting a frequency regulation dead zone range. Then, combined with the preset frequency regulation dead zone range, three current frequency regulation control strategies are constructed. Thus, when the frequency regulation pressure is relatively small, i.e., the current frequency deviation is within the preset frequency regulation dead zone range, the system can better complete the frequency regulation task in the next stage by reasonably restoring its own state of charge. When the current frequency deviation is not within the preset frequency regulation dead zone range and the energy storage components need to participate in primary frequency regulation, the output size and output sequence of each type of energy storage are determined by combining the frequency regulation characteristics of each type of energy storage, the remaining capacity of frequency regulation, and the actual operating parameters, so as to meet the charging and discharging needs respectively, thereby realizing the rapid and effective restoration of the system frequency to a normal stable state. This invention, taking into account different types of energy storage devices, can scientifically and efficiently solve the problems of power distribution in hybrid energy storage and frequency stability during primary frequency regulation of the power grid. It fully leverages the advantages of hybrid energy storage systems in terms of flexible control and rapid response, alleviates the pressure on power grid frequency regulation brought about by large-scale new energy grid connection, and enables safe and stable access for various types of generating units. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a flowchart illustrating the primary frequency regulation control method for the hybrid energy storage power station of the present invention.

[0047] Figure 2 This is a schematic diagram of the primary frequency regulation control system of the hybrid energy storage power station of the present invention. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] This invention provides a primary frequency regulation control method and system for a hybrid energy storage power station. The method is scientific, simple, and easy to operate.

[0050] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] Example 1

[0052] like Figure 1 As shown, this invention provides a primary frequency regulation control method for a hybrid energy storage power station, applied to a hybrid energy storage power station comprising two sets of energy storage components, namely a lithium battery and a supercapacitor energy storage system; the primary frequency regulation control method includes:

[0053] Step 100: Obtain the current frequency deviation of the hybrid energy storage power station and the current state of charge of each of the two sets of energy storage components. The formula for calculating the current frequency deviation is:

[0054] Δf=f0-f N .

[0055] In the formula, Δf represents the current frequency deviation, f0 represents the power output of the power station before the frequency regulation command is issued, and f N This indicates the system's rated frequency.

[0056] Step 200: When the current frequency deviation is not within the preset frequency regulation dead zone, the hybrid energy storage power station participates in primary frequency regulation. In the primary frequency regulation step, it is first determined whether the current frequency deviation is greater than zero.

[0057] Step 300: If the current frequency deviation is greater than zero, then based on the current state of charge of the two sets of energy storage components, determine the charging priority of the two sets of energy storage components; based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of the two sets of energy storage components, determine the first current frequency regulation control strategy of the hybrid energy storage power station; the first current frequency regulation control strategy is used to achieve frequency regulation control that meets charging requirements.

[0058] (1) Based on the current state of charge of each of the two sets of energy storage components, determine the charging priority of the two sets of energy storage components, specifically including:

[0059] 11) When the current state of charge of the lithium battery is higher than or equal to the current state of charge of the supercapacitor energy storage system, the charging priority is: the supercapacitor energy storage system is charged first, and the lithium battery is charged to meet the charging requirements.

[0060] 12) When the current state of charge of the lithium battery is lower than the current state of charge of the supercapacitor energy storage system, the charging priority is: the lithium battery is charged first, and the supercapacitor energy storage system is charged to meet the charging requirements.

[0061] In one specific embodiment, the determination of the relative levels of the current state of charge (S) of the lithium battery and the supercapacitor energy storage system can be based on a preset higher S value. high and the preset lower state of charge value S low Confirmed. Please refer to Table 1 below for details.

[0062] Table 1

[0063]

[0064] In Table 1, states S1, S2, S3, S5, S6, and S9 are as follows: states S2, S3, and S6 indicate that the SOC of the lithium battery is higher than that of the supercapacitor energy storage system; states S1, S5, and S9 indicate that the SOCs of the lithium battery and the supercapacitor are at the same level. To ensure that the lithium battery has a certain degree of regulation capability in the next time period and to fully utilize the advantage of the supercapacitor having no limit on the number of charge-discharge cycles, a strategy is adopted in which the supercapacitor energy storage system is charged first, and the lithium battery energy storage system supplements the remaining charging needs.

[0065] In states S4, S7, and S8, the SOC level of the supercapacitor energy storage system is higher than that of the lithium battery. This is partly due to the large storage capacity of lithium batteries as energy storage devices, and partly because supercapacitors should reserve a certain charging capacity for the next period's adjustment tasks. Therefore, a strategy is adopted where lithium batteries are charged first, and the supercapacitor energy storage system supplements the remaining charging demand.

[0066] (2) Based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge corresponding to each of the two sets of energy storage components, a first current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including:

[0067] 21) Based on virtual droop control, and according to the current frequency deviation and the preset frequency regulation dead zone range, calculate the first current frequency regulation action of the hybrid energy storage power station. The specific calculation formula is as follows:

[0068] ΔP c_hess =-Khess (Δf-f d ); where ΔP c_hess Indicates the first frequency modulation action, f d Indicates the preset FM dead zone range, K hess This represents the droop coefficient.

[0069] 22) Calculate the maximum charging power of the lithium battery based on its current state of charge; calculate the maximum charging power of the supercapacitor energy storage system based on its current state of charge. Specifically, real-time operating information of the hybrid energy storage power station is collected, including the state of charge of the lithium battery and the supercapacitor energy storage system. A Logistic regression function is introduced to obtain the corresponding maximum charging power of the lithium battery and the supercapacitor energy storage system.

[0070] The formula for calculating the maximum charging power of the lithium battery is:

[0071]

[0072] The formula for calculating the maximum charging power of the supercapacitor energy storage system is as follows:

[0073]

[0074] Among them, P c_bmax P represents the maximum charging power of a lithium battery. cN_b This represents the rated charging power of the lithium battery, e represents the exponent, and n and P0 are both adaptation factors. The values ​​of these two adaptation factors are not unique and can be adjusted appropriately according to actual needs; SOC_b max SOC_b represents the maximum state of charge (SOC) of the lithium battery, while SOC_b represents the current state of charge (SOC) of the lithium battery. high This indicates a relatively high state of charge (SOC) value for the lithium battery; P c_scmax P represents the maximum charging power of the supercapacitor energy storage system. cN_sc SOC_sc represents the rated charging power of the supercapacitor energy storage system. max SOC_sc represents the maximum state of charge (SOC) of the supercapacitor energy storage system, while SOC_sc represents the current state of charge (SOC) of the supercapacitor energy storage system. high This indicates the higher state of charge (SOC) value of the supercapacitor energy storage system; and both the higher SOC values ​​of the lithium battery and the supercapacitor energy storage system are preset values.

[0075] 23) Based on the charging priority, the maximum charging power of the lithium battery, the maximum charging power of the supercapacitor energy storage system, and the first current frequency regulation action of the hybrid energy storage power station, determine the first current frequency regulation control strategy of the hybrid energy storage power station. Specifically, the process of determining the first current frequency regulation control strategy of the hybrid energy storage power station includes:

[0076] When the charging priority is: the supercapacitor energy storage system is charged first, and the lithium battery is charged to meet the charging requirements, according to the formula...

[0077]

[0078] Determine the first current frequency regulation control strategy for the hybrid energy storage power station.

[0079] When the charging priority is: the lithium battery is charged first, and the supercapacitor energy storage system replenishes the remaining charge until the charging demand is met, according to the formula...

[0080]

[0081] Determine the first current frequency regulation control strategy for the hybrid energy storage power station.

[0082] Among them, P c_b P represents the charging power value of the lithium battery used for frequency modulation control. c_sc This represents the charging power value used for frequency regulation control in a supercapacitor energy storage system, and max() represents the function to find the maximum value.

[0083] Step 400: If the current frequency deviation is less than or equal to zero, then the discharge priority of the two sets of energy storage components is determined based on their respective current states of charge; based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone range, and the respective current states of charge of the two sets of energy storage components, a second current frequency regulation control strategy for the hybrid energy storage power station is determined; the second current frequency regulation control strategy is used to achieve frequency regulation control that meets the discharge requirements.

[0084] (1) Based on the current state of charge of each of the two sets of energy storage components, determine the discharge priority of the two sets of energy storage components, specifically including:

[0085] 11) Specifically, as shown in Table 1 above, in states S1, S2, S3, S5, S6, and S9, the current state of charge of the lithium battery is higher than or equal to the current state of charge of the supercapacitor energy storage system. In order to ensure that the lithium battery has a certain adjustment capability in the next period and to make full use of the advantage of the supercapacitor having no limit on the number of charge and discharge cycles, the discharge priority is: the lithium battery is given priority to discharge, and the supercapacitor energy storage system replenishes the remaining discharge until the discharge demand is met.

[0086] 12) Specifically, as can be seen from Table 1 above, in states S4, S7, and S8, the current state of charge of the lithium battery is lower than the current state of charge of the supercapacitor energy storage system. This is because the lithium battery, as an energy storage element, has a large storage capacity, and the supercapacitor should reserve a certain charging capacity for the next period of adjustment. The discharge priority is as follows: the supercapacitor energy storage system discharges first, and the lithium battery discharges the remaining amount until the discharge demand is met.

[0087] (2) Based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge corresponding to each of the two sets of energy storage components, a second current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including:

[0088] 21) Based on virtual droop control, and according to the current frequency deviation and the preset frequency regulation dead zone range, calculate the second current primary frequency regulation action of the hybrid energy storage power station. The specific calculation formula is as follows:

[0089] ΔP d_hess =-K hess (Δf+f d ); where ΔP d_hess This indicates the second frequency modulation action.

[0090] 22) Calculate the maximum discharge power of the lithium battery based on its current state of charge; calculate the maximum discharge power of the supercapacitor energy storage system based on its current state of charge.

[0091] The formula for calculating the maximum discharge power of the lithium battery is:

[0092]

[0093] The formula for calculating the maximum discharge power of the supercapacitor energy storage system is as follows:

[0094]

[0095] Among them, P d_bmax P represents the maximum discharge power of a lithium battery. dN_b SOC_b represents the rated discharge power of the lithium battery. min SOC_b represents the minimum state of charge (SOC) of the lithium battery, while SOC_b represents the current state of charge (SOC) of the lithium battery. low This indicates a lower state of charge (SOC) value for the lithium battery; P d_scmax P represents the maximum discharge power of the supercapacitor energy storage system. dN_sc SOC_sc represents the rated discharge power of the supercapacitor energy storage system.min SOC_sc represents the minimum state of charge (SOC) of the supercapacitor energy storage system, while SOC_sc represents the current state of charge (SOC) of the supercapacitor energy storage system. low This indicates the lower state of charge (SOC) value of the supercapacitor energy storage system; and the higher SOC values ​​of both the lithium battery and the supercapacitor energy storage system are preset values.

[0096] 23) Based on the discharge priority, the maximum discharge power of the lithium battery, the maximum discharge power of the supercapacitor energy storage system, and the second current frequency regulation action of the hybrid energy storage power station, determine the second current frequency regulation control strategy of the hybrid energy storage power station.

[0097] The process of determining the second current frequency regulation control strategy of the hybrid energy storage power station specifically includes:

[0098] When the discharge priority of the two energy storage components is: the lithium battery discharges first, and the supercapacitor energy storage system replenishes the remaining discharge until the discharge demand is met, according to the formula...

[0099]

[0100] Determine the second current frequency regulation control strategy for the hybrid energy storage power station;

[0101] When the discharge priority of the two energy storage components is: the supercapacitor energy storage system discharges first, and the lithium battery replenishes the remaining discharge until the discharge demand is met, according to the formula...

[0102]

[0103] Determine the second current frequency regulation control strategy for the hybrid energy storage power station;

[0104] Among them, P d_b P represents the discharge power value of the lithium battery used for frequency modulation control. d_sc This represents the discharge power value used for frequency regulation control in a supercapacitor energy storage system, and min() represents the function to find the minimum value.

[0105] In a hybrid energy storage power station, each group of energy storage components outputs power according to the calculated current frequency regulation control strategy until the grid frequency returns to a normal and stable level.

[0106] Step 500: When the current frequency deviation is within the preset frequency regulation dead zone range, a third current frequency regulation control strategy for the hybrid energy storage power station is determined based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components; the third current frequency regulation control strategy is used to realize the self-recovering frequency regulation control of any energy storage component.

[0107] Specifically, based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components, a third current frequency regulation control strategy for the hybrid energy storage power station is determined, including:

[0108] (1) Based on the current state of charge of the lithium battery, calculate the self-recovery charging power requirement and the self-recovery discharging power requirement of the lithium battery; based on the current state of charge of the supercapacitor energy storage system, calculate the self-recovery charging power requirement and the self-recovery discharging power requirement of the supercapacitor energy storage system. Specifically, this includes:

[0109] The formula for calculating the self-recovery charging power requirement of the lithium battery is as follows:

[0110]

[0111] The formula for calculating the self-recovery discharge power requirement of the lithium battery is as follows:

[0112]

[0113] The formula for calculating the self-recovery charging power requirement of the supercapacitor energy storage system is as follows:

[0114]

[0115] The formula for calculating the self-recovery discharge power requirement of the supercapacitor energy storage system is as follows:

[0116]

[0117] Among them, P c_b1 This indicates the self-recovery charging power requirement of the lithium battery; SOC1 and SOC0 are preset values, mainly used to adjust the curve according to the high and low SOC states, specifically SOC1 can be 0.725 and SOC0 can be 0.275; P d_b1 P represents the power required for the self-recovery discharge of a lithium battery. c_sc1 P represents the self-recovery charging power requirement of a supercapacitor energy storage system. d_sc1 This indicates the self-recovery discharge power requirement of the supercapacitor energy storage system.

[0118] (2) Based on the current frequency deviation and the preset frequency tuning dead zone range, calculate the charging power constraint and discharging power constraint of the lithium battery and the charging power constraint and discharging power constraint of the supercapacitor energy storage system respectively.

[0119] The charging power constraint P of the lithium battery c_b2 The calculation formula is:

[0120]

[0121] The discharge power constraint P of the lithium battery d_b2 The calculation formula is:

[0122]

[0123] The charging power constraint P of the supercapacitor energy storage system c_sc2 The calculation formula is:

[0124]

[0125] The discharge power constraint P of the supercapacitor energy storage system d_sc2 The calculation formula is:

[0126]

[0127] (3) Determine the actual self-recovery power of the lithium battery based on its current state of charge, charging power constraint, discharging power constraint, self-recovery charging power requirement, and self-recovery discharging power requirement; determine the actual self-recovery power of the supercapacitor energy storage system based on its current state of charge, charging power constraint, discharging power constraint, self-recovery charging power requirement, and self-recovery discharging power requirement.

[0128] The process of determining the actual self-recovery power of a lithium battery specifically includes:

[0129] 11) If the current state of charge (SOC) of the lithium battery is less than the lower SOC value, then the actual recovery power of the lithium battery is determined based on the self-recovery charging power requirement and the charging power constraint; the specific determination formula is as follows:

[0130] P ess_b =-min(|P c_b1 |,|P c_b2 |),SOC_b<SOC_b low .

[0131] 12) If the current state of charge (SOC) of the lithium battery is greater than the higher SOC value, then the actual recovery power of the lithium battery is determined based on the self-recovery discharge power requirement and the discharge power constraint; the specific determination formula is as follows:

[0132] P ess_b =min(|P d_b1 |,|P d_b2 |),SOC_b>SOC_b high .

[0133] 13) If the current state of charge of the lithium battery is greater than or equal to the lower state of charge of the lithium battery, and less than or equal to the higher state of charge of the lithium battery, then the actual recovery power of the lithium battery is 0.

[0134] The process of determining the actual self-recovering power of a supercapacitor energy storage system specifically includes:

[0135] 21) If the current state of charge (SOC) of the supercapacitor energy storage system is less than the lower SOC value, then the actual recovery power of the supercapacitor energy storage system is determined based on the self-recovery charging power requirement and the charging power constraint; the specific determination formula is as follows:

[0136] P ess_sc =-min(|P c_sc1 |,|P c_sc2 |),SOC_sc<SOC_sc low .

[0137] 22) If the current state of charge (SOC) of the supercapacitor energy storage system is greater than the higher SOC value of the supercapacitor energy storage system, then the actual recovery power of the supercapacitor energy storage system is determined based on the self-recovery discharge demand power of the supercapacitor energy storage system and the discharge power constraint; the specific determination formula is as follows:

[0138] P ess_sc =min(|P d_sc1 |,|P d_sc2 |),SOC_sc>SOC_sc high .

[0139] 23) If the current state of charge of the supercapacitor energy storage system is greater than or equal to the lower state of charge value of the supercapacitor energy storage system, and less than or equal to the higher state of charge value of the supercapacitor energy storage system, then the actual recovery power of the supercapacitor energy storage system is 0.

[0140] In summary, to address the issues of complex solution processes, large computational costs, and numerous constraints associated with optimization-based power allocation strategies, this invention, based on droop control and independent of optimization design, enables rapid and convenient calculation of primary frequency modulation allocation methods in real-time applications.

[0141] To address the issue that using only a single droop control strategy fails to consider the coordination of power output from different types of energy storage systems, this invention fully considers the frequency regulation characteristics and remaining frequency regulation capacity of different energy storage types to allocate power, thus fully leveraging the advantages of hybrid energy storage.

[0142] To address the issue that studying only the power distribution among different types of energy storage during frequency regulation fails to consider the self-recovery of the energy storage's state of charge, thus affecting the energy storage's lifespan and subsequent frequency regulation performance, this invention establishes a frequency regulation dead zone for hybrid energy storage power stations. It considers the power demand for energy storage self-recovery charging and discharging, as well as the real-time operating status of the power grid, to constrain the maximum charging and discharging power of the energy storage. This determines the control strategy for the energy storage's self-recovery state of charge, thereby improving the utilization lifespan of the energy storage system.

[0143] Example 2

[0144] like Figure 2 As shown, in order to implement the technical solution in Embodiment 1 and achieve the corresponding functions and technical effects, this embodiment provides a primary frequency regulation control system for a hybrid energy storage power station, applied to a hybrid energy storage power station. The hybrid energy storage power station includes two sets of energy storage components, and the system includes:

[0145] The data acquisition module 101 is used to acquire the current frequency deviation of the hybrid energy storage power station and the current state of charge of each of the two sets of energy storage components.

[0146] The frequency deviation judgment module 201 is used to determine whether the current frequency deviation is greater than zero when the current frequency deviation is not within the preset frequency tuning dead zone range.

[0147] The first frequency regulation control module 301 is used to determine the charging priority of the two sets of energy storage components based on their respective current states of charge when the current frequency deviation is greater than zero; and to determine the first current frequency regulation control strategy of the hybrid energy storage power station based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone range, and the respective current states of charge of the two sets of energy storage components; the first current frequency regulation control strategy is used to achieve frequency regulation control that meets charging requirements.

[0148] The second frequency regulation control module 401 is used to determine the discharge priority of the two sets of energy storage components based on their respective current states of charge when the current frequency deviation is less than or equal to zero; and to determine a second current frequency regulation control strategy for the hybrid energy storage power station based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone range, and the respective current states of charge of the two sets of energy storage components; the second current frequency regulation control strategy is used to achieve frequency regulation control that meets the discharge requirements.

[0149] The third frequency regulation control module 501 is used to determine the third current frequency regulation control strategy of the hybrid energy storage power station based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components when the current frequency deviation is within the preset frequency regulation dead zone range; the third current frequency regulation control strategy is used to realize the self-recovery frequency regulation control of any energy storage component.

[0150] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0151] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A primary frequency regulation control method for a hybrid energy storage power station, applied to a hybrid energy storage power station comprising two sets of energy storage components, characterized in that, The methods include: Obtain the current frequency deviation of the hybrid energy storage power station and the current state of charge of each of the two sets of energy storage components; When the current frequency deviation is not within the preset frequency tuning dead zone range, determine whether the current frequency deviation is greater than zero; If the current frequency deviation is greater than zero, the charging priority of the two sets of energy storage components is determined based on their respective current states of charge; and the first current frequency regulation control strategy of the hybrid energy storage power station is determined based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone range, and the respective current states of charge of the two sets of energy storage components. The first current frequency modulation control strategy is used to achieve frequency modulation control that meets charging requirements; If the current frequency deviation is less than or equal to zero, the discharge priority of the two sets of energy storage components is determined based on their respective current states of charge. Based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components, a second current frequency regulation control strategy for the hybrid energy storage power station is determined. The second current frequency modulation control strategy is used to achieve frequency modulation control that meets the discharge requirements; When the current frequency deviation is within the preset frequency regulation dead zone range, the third current frequency regulation control strategy of the hybrid energy storage power station is determined based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components. The third current frequency modulation control strategy is used to achieve self-recovering frequency modulation control for any energy storage component; The two sets of energy storage components are a lithium battery and a supercapacitor energy storage system, respectively. Based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components, a third current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including: Based on the current state of charge of the lithium battery, calculate the self-recovery charging power requirement and the self-recovery discharging power requirement of the lithium battery; based on the current state of charge of the supercapacitor energy storage system, calculate the self-recovery charging power requirement and the self-recovery discharging power requirement of the supercapacitor energy storage system. Based on the current frequency deviation and the preset frequency tuning dead zone range, the charging power constraints and discharging power constraints of the lithium battery and the charging power constraints and discharging power constraints of the supercapacitor energy storage system are calculated respectively. The actual self-recovery power of the lithium battery is determined based on its current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirement, and self-recovery discharging power requirement; the actual self-recovery power of the supercapacitor energy storage system is determined based on its current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirement, and self-recovery discharging power requirement. Based on the current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirements, and self-recovery discharging power requirements of the lithium battery, the actual self-recovery power of the lithium battery is determined, specifically including: If the current state of charge of the lithium battery is less than the lower state of charge value of the lithium battery, then the actual recovery power of the lithium battery is determined according to the self-recovery charging power requirement of the lithium battery and the charging power constraint. If the current state of charge of the lithium battery is greater than the higher state of charge value of the lithium battery, then the actual recovery power of the lithium battery is determined according to the self-recovery discharge demand power of the lithium battery and the discharge power constraint. If the current state of charge of the lithium battery is greater than or equal to the lower state of charge value of the lithium battery, and less than or equal to the higher state of charge value of the lithium battery, then the actual recovery power of the lithium battery is 0; wherein, the higher state of charge value and the lower state of charge value of the lithium battery are both preset values. If the current state of charge of the supercapacitor energy storage system is less than the lower state of charge value of the supercapacitor energy storage system, then the actual recovery power of the supercapacitor energy storage system is determined according to the self-recovery charging demand power of the supercapacitor energy storage system and the charging power constraint. If the current state of charge of the supercapacitor energy storage system is greater than the higher state of charge value of the supercapacitor energy storage system, then the actual recovery power of the supercapacitor energy storage system is determined according to the self-recovery discharge demand power of the supercapacitor energy storage system and the discharge power constraint. If the current state of charge of the supercapacitor energy storage system is greater than or equal to the lower state of charge value of the supercapacitor energy storage system, and less than or equal to the higher state of charge value of the supercapacitor energy storage system, then the actual recovery power of the supercapacitor energy storage system is 0.

2. The primary frequency regulation control method for a hybrid energy storage power station according to claim 1, characterized in that, The two sets of energy storage components are a lithium battery and a supercapacitor energy storage system, respectively. Based on the current state of charge of each of the two sets of energy storage components, the charging priority of the two sets of energy storage components is determined, specifically including: When the current state of charge of the lithium battery is higher than or equal to the current state of charge of the supercapacitor energy storage system, the charging priority is: the supercapacitor energy storage system is charged first, and the lithium battery is charged to meet the charging requirements. When the current state of charge of the lithium battery is lower than the current state of charge of the supercapacitor energy storage system, the charging priority is: the lithium battery is charged first, and the supercapacitor energy storage system is charged to meet the charging requirements.

3. The primary frequency regulation control method for a hybrid energy storage power station according to claim 2, characterized in that, Based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components, a first current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including: Based on virtual droop control, the first current frequency regulation action of the hybrid energy storage power station is calculated according to the current frequency deviation and the preset frequency regulation dead zone range; Calculate the maximum charging power of the lithium battery based on its current state of charge; calculate the maximum charging power of the supercapacitor energy storage system based on its current state of charge. Based on the charging priority, the maximum charging power of the lithium battery, the maximum charging power of the supercapacitor energy storage system, and the first current frequency regulation action of the hybrid energy storage power station, the first current frequency regulation control strategy of the hybrid energy storage power station is determined.

4. The primary frequency regulation control method for a hybrid energy storage power station according to claim 3, characterized in that, The formula for calculating the maximum charging power of the lithium battery is: ； The formula for calculating the maximum charging power of the supercapacitor energy storage system is as follows: ； in, P c_bmax This indicates the maximum charging power of the lithium battery. P cN_b This indicates the rated charging power of the lithium battery. e Indicates an index. n and P 0 All are adaptation factors. SOC_b max This indicates the maximum state of charge (SOC) of the lithium battery. SOC_b This indicates the current state of charge of the lithium battery. SOC_b high This indicates a relatively high state of charge (SOC) value for the lithium battery. P c_scmax This indicates the maximum charging power of the supercapacitor energy storage system. P cN_sc This indicates the rated charging power of the supercapacitor energy storage system. SOC_sc max This represents the maximum state of charge of the supercapacitor energy storage system. SOC_sc This indicates the current state of charge of the supercapacitor energy storage system. SOC_sc high This indicates the higher state of charge (SOC) value of the supercapacitor energy storage system; and both the higher SOC values ​​of the lithium battery and the supercapacitor energy storage system are preset values.

5. The primary frequency regulation control method for a hybrid energy storage power station according to claim 3, characterized in that, The process of determining the first current frequency regulation control strategy of the hybrid energy storage power station specifically includes: When the charging priority is: the supercapacitor energy storage system is charged first, and the lithium battery is charged to meet the charging requirements, according to the formula... Determine the first current frequency regulation control strategy for the hybrid energy storage power station; When the charging priority is: the lithium battery is charged first, and the supercapacitor energy storage system replenishes the remaining charge until the charging demand is met, according to the formula... Determine the first current frequency regulation control strategy for the hybrid energy storage power station; in, P c_b This indicates the charging power value of the lithium battery used for frequency modulation control. P c_sc This indicates the charging power value used for frequency regulation control in a supercapacitor energy storage system. P c_bmax This indicates the maximum charging power of the lithium battery. P c_scmax This indicates the maximum charging power of the supercapacitor energy storage system. This indicates the first frequency regulation action of the hybrid energy storage power station, and max() represents the function to find the maximum value.

6. The primary frequency regulation control method for a hybrid energy storage power station according to claim 1, characterized in that, The two sets of energy storage components are a lithium battery and a supercapacitor energy storage system, respectively. Based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components, a second current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including: Based on virtual droop control, the second current primary frequency regulation action of the hybrid energy storage power station is calculated according to the current frequency deviation and the preset frequency regulation dead zone range; Calculate the maximum discharge power of the lithium battery based on its current state of charge; calculate the maximum discharge power of the supercapacitor energy storage system based on its current state of charge. Based on the discharge priority, the maximum discharge power of the lithium battery, the maximum discharge power of the supercapacitor energy storage system, and the second current frequency regulation action of the hybrid energy storage power station, the second current frequency regulation control strategy of the hybrid energy storage power station is determined.

7. The primary frequency regulation control method for a hybrid energy storage power station according to claim 1, characterized in that, The formula for calculating the self-recovery charging power requirement of the lithium battery is as follows: ； The formula for calculating the self-recovery discharge power requirement of the lithium battery is as follows: ； The formula for calculating the self-recovery charging power requirement of the supercapacitor energy storage system is as follows: ； The formula for calculating the self-recovery discharge power requirement of the supercapacitor energy storage system is as follows: ； in, P c_b1 This indicates the power required for the self-recovery charging of the lithium battery. P cN_b This indicates the rated charging power of the lithium battery. e Indicates an index. n and P 0 All are adaptation factors. SOC_b max This indicates the maximum state of charge (SOC) of the lithium battery. SOC_b This indicates the current state of charge of the lithium battery. SOC_b high This indicates a relatively high state of charge (SOC) value for the lithium battery; both SOC1 and SOC0 are preset values. P d_b1 This indicates the power required for the self-recovery discharge of a lithium battery. P d_bmax This indicates the maximum discharge power of the lithium battery. P dN_b This indicates the rated discharge power of the lithium battery. SOC_b min This represents the minimum state of charge (SOC) of a lithium battery. SOC_b This indicates the current state of charge of the lithium battery. SOC_ b low This indicates a low state of charge (SOC) value for the lithium battery. P c_sc1 This indicates the power required for the self-recovery charging of the supercapacitor energy storage system. P c_scmax This indicates the maximum charging power of the supercapacitor energy storage system. P cN_sc This indicates the rated charging power of the supercapacitor energy storage system. SOC_sc max This represents the maximum state of charge of the supercapacitor energy storage system. SOC_sc This indicates the current state of charge of the supercapacitor energy storage system. SOC_sc high This indicates a relatively high state of charge (SOC) value for the supercapacitor energy storage system. P d_sc1 This indicates the self-recovery discharge power requirement of the supercapacitor energy storage system. P d_scmax This indicates the maximum discharge power of the supercapacitor energy storage system. P dN_sc This indicates the rated discharge power of the supercapacitor energy storage system. SOC_sc min This represents the minimum state of charge of a supercapacitor energy storage system. SOC_sc This indicates the current state of charge of the supercapacitor energy storage system. SOC_sc low This indicates a low state of charge (SOC) value for the supercapacitor energy storage system.

8. A primary frequency regulation control system for a hybrid energy storage power station, applied to a hybrid energy storage power station comprising two sets of energy storage components, characterized in that, The system includes: The data acquisition module is used to acquire the current frequency deviation of the hybrid energy storage power station and the current state of charge of each of the two sets of energy storage components. The frequency deviation judgment module is used to determine whether the current frequency deviation is greater than zero when the current frequency deviation is not within the preset frequency tuning dead zone range. The first frequency regulation control module is used to determine the charging priority of the two sets of energy storage components based on their respective current states of charge when the current frequency deviation is greater than zero; and to determine a first current frequency regulation control strategy for the hybrid energy storage power station based on the charging priority, the current frequency deviation, the preset frequency regulation dead zone range, and the respective current states of charge of the two sets of energy storage components; the first current frequency regulation control strategy is used to achieve frequency regulation control that meets charging requirements. The second frequency regulation control module is used to determine the discharge priority of the two sets of energy storage components based on their respective current states of charge when the current frequency deviation is less than or equal to zero; and to determine a second current frequency regulation control strategy for the hybrid energy storage power station based on the discharge priority, the current frequency deviation, the preset frequency regulation dead zone range, and the respective current states of charge of the two sets of energy storage components; the second current frequency regulation control strategy is used to achieve frequency regulation control that meets the discharge requirements. The third frequency regulation control module is used to determine the third current frequency regulation control strategy of the hybrid energy storage power station based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components when the current frequency deviation is within the preset frequency regulation dead zone range; the third current frequency regulation control strategy is used to realize the self-recovery frequency regulation control of any energy storage component. The two sets of energy storage components are a lithium battery and a supercapacitor energy storage system, respectively. Based on the current frequency deviation, the preset frequency regulation dead zone range, and the current state of charge of each of the two sets of energy storage components, a third current frequency regulation control strategy for the hybrid energy storage power station is determined, specifically including: Based on the current state of charge of the lithium battery, calculate the self-recovery charging power requirement and the self-recovery discharging power requirement of the lithium battery; based on the current state of charge of the supercapacitor energy storage system, calculate the self-recovery charging power requirement and the self-recovery discharging power requirement of the supercapacitor energy storage system. Based on the current frequency deviation and the preset frequency tuning dead zone range, the charging power constraints and discharging power constraints of the lithium battery and the charging power constraints and discharging power constraints of the supercapacitor energy storage system are calculated respectively. The actual self-recovery power of the lithium battery is determined based on its current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirement, and self-recovery discharging power requirement; the actual self-recovery power of the supercapacitor energy storage system is determined based on its current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirement, and self-recovery discharging power requirement. Based on the current state of charge, charging power constraints, discharging power constraints, self-recovery charging power requirements, and self-recovery discharging power requirements of the lithium battery, the actual self-recovery power of the lithium battery is determined, specifically including: If the current state of charge of the lithium battery is less than the lower state of charge value of the lithium battery, then the actual recovery power of the lithium battery is determined according to the self-recovery charging power requirement of the lithium battery and the charging power constraint. If the current state of charge of the lithium battery is greater than the higher state of charge value of the lithium battery, then the actual recovery power of the lithium battery is determined according to the self-recovery discharge demand power of the lithium battery and the discharge power constraint. If the current state of charge of the lithium battery is greater than or equal to the lower state of charge value of the lithium battery, and less than or equal to the higher state of charge value of the lithium battery, then the actual recovery power of the lithium battery is 0; wherein, the higher state of charge value and the lower state of charge value of the lithium battery are both preset values. If the current state of charge of the supercapacitor energy storage system is less than the lower state of charge value of the supercapacitor energy storage system, then the actual recovery power of the supercapacitor energy storage system is determined according to the self-recovery charging demand power of the supercapacitor energy storage system and the charging power constraint. If the current state of charge of the supercapacitor energy storage system is greater than the higher state of charge value of the supercapacitor energy storage system, then the actual recovery power of the supercapacitor energy storage system is determined according to the self-recovery discharge demand power of the supercapacitor energy storage system and the discharge power constraint. If the current state of charge of the supercapacitor energy storage system is greater than or equal to the lower state of charge value of the supercapacitor energy storage system, and less than or equal to the higher state of charge value of the supercapacitor energy storage system, then the actual recovery power of the supercapacitor energy storage system is 0.

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