Power evaluation method and device for hybrid energy storage system

Abstract

The invention discloses a power evaluation method and device for a hybrid energy storage system. The method comprises the following steps: acquiring a frequency modulation instruction of a power system; according to the output characteristics of the gravity energy storage subsystem, a gravity power range corresponding to the frequency modulation instruction is given; comparing the gravity control instruction with the gravity power range, and analyzing the electrochemical power corresponding to the gravity control instruction; and the total power range of the hybrid energy storage system is given in combination with the working state of the hybrid energy storage system. According to the method, the frequency modulation instruction sent by the power system is obtained in time, the gravity power range is determined according to the frequency modulation instruction in combination with the output characteristics of the gravity energy storage subsystem, the electrochemical power is determined based on the gravity power range, and finally the total power range of the hybrid energy storage system in different working states is obtained. The gravity power range and the electrochemical power are sequentially determined according to the frequency modulation instruction capable of reflecting the actual demand of the power system, the total power range of the hybrid energy storage system is finally obtained, and the accuracy of power evaluation of the hybrid energy storage system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hybrid energy storage evaluation, and in particular relates to a power evaluation method and device for a hybrid energy storage system. Background Art

[0002] Renewable energy has characteristics such as randomness, intermittency and volatility, which makes the power supply in the power system connected to renewable energy difficult to predict and prone to violent fluctuations, affecting the frequency stability and power balance of the power system.

[0003] In order to solve this problem, integrating energy storage systems with power systems containing renewable resources can effectively enhance the flexibility and reliability of power systems. The large-scale application of energy storage systems is conducive to improving the flexibility, economy and safety of power systems.

[0004] Gravity energy storage systems have the advantages of high safety, clean and environmental protection, flexible site selection, and low overall cost. For example, the existing vertical matrix gravity energy storage system uses the lifting and lowering movement of heavy blocks in the vertical direction to efficiently convert gravitational potential energy into electrical energy, thereby realizing energy storage and release. However, the mechanical structure characteristics of the gravity energy storage system inherently determine that the speed of change of its output power is limited by physical processes, and it cannot immediately respond to the power fluctuation requirements of the power system, making the gravity energy storage system alone insufficient to meet the power system's requirements for real-time regulation capabilities and dynamic response speed. It is necessary to design a hybrid energy storage system that connects gravity energy storage and electrochemical energy storage in parallel to better meet the power requirements of the power system.

[0005] For example, patent CN118868166A discloses a capacity planning method for configuring electrochemical energy storage in a mechanical energy storage power station, determines the power regulation response function of gravity energy storage, calculates the electrochemical energy storage capacity that meets the grid assessment requirements, and optimizes the configuration capacity of electrochemical energy storage. Through the response function of gravity energy storage power regulation, the response performance of single instructions and multiple instructions under different load levels is analyzed, and the configuration power and capacity of electrochemical energy storage are calculated to improve the regulation performance of gravity energy storage, meet the assessment requirements of grid primary frequency regulation and automatic power generation control, and improve the comprehensive frequency regulation performance indicators.

[0006] When constructing a hybrid energy storage system that includes gravity energy storage and electrochemical energy storage, how to improve the accuracy of power assessment of the hybrid energy storage system to ensure the frequency stability and power balance of the power system is a problem that needs to be solved at present. Summary of the invention

[0007] In view of the defects existing in the above-mentioned prior art, the present invention provides a power evaluation method and device for a hybrid energy storage system, the method comprising: obtaining the frequency modulation instruction of the power system; according to the output characteristics of the gravity energy storage subsystem, giving the gravity power range corresponding to the frequency modulation instruction; comparing the gravity control instruction and the gravity power range, analyzing the electrochemical power corresponding to the gravity control instruction; and giving the total power range of the hybrid energy storage system in combination with the working state of the hybrid energy storage system. The present invention obtains the frequency modulation instruction issued by the power system in a timely manner, determines the gravity power range according to the frequency modulation instruction combined with the output characteristics of the gravity energy storage subsystem, and determines the electrochemical power based on this, and finally obtains the total power range of the hybrid energy storage system under different working states. According to the frequency modulation instruction that can reflect the actual needs of the power system, the gravity power range and the electrochemical power are determined in turn, and finally the total power range of the hybrid energy storage system is obtained, thereby improving the accuracy of the power evaluation of the hybrid energy storage system.

[0008] In a first aspect, a power evaluation method for a hybrid energy storage system includes:

[0009] Obtaining a frequency modulation instruction of the power system, wherein the frequency modulation instruction includes a gravity control instruction for a gravity energy storage subsystem in the hybrid energy storage system and an electrochemical control instruction for an electrochemical energy storage subsystem in the hybrid energy storage system;

[0010] According to the output characteristics of the gravity energy storage subsystem, the gravity power range corresponding to the frequency modulation instruction is given, wherein the output characteristics include the power constraint and the ramp rate constraint of the gravity energy storage subsystem;

[0011] Compare the gravity control instructions and gravity power range, and analyze the electrochemical power corresponding to the gravity control instructions;

[0012] Combined with the working state of the hybrid energy storage system, the total power range of the hybrid energy storage system is given.

[0013] It can be seen from the above technical solution that by timely obtaining the frequency modulation instructions issued by the power system, the gravity power range is determined according to the frequency modulation instructions combined with the output characteristics of the gravity energy storage subsystem, and the electrochemical power is determined based on this, and finally the total power range of the hybrid energy storage system under different working conditions is obtained. According to the frequency modulation instructions that can reflect the actual needs of the power system, the gravity power range and electrochemical power are determined in turn, and finally the total power range of the hybrid energy storage system is obtained, which improves the accuracy of the power evaluation of the hybrid energy storage system.

[0014] Furthermore, the frequency regulation command of the power system is determined by:

[0015] Obtaining the initial control signal from the power system;

[0016] Perform variational mode decomposition on the initial control signal to obtain n intrinsic mode function components;

[0017] The high frequency components among the n intrinsic mode function components are used as electrochemical control instructions, and the low frequency components among the n intrinsic mode function components are used as gravity control instructions.

[0018] Furthermore, the gravity control instruction and the electrochemical control instruction are specifically expressed as:

[0019]

[0020] in, is the gravity control command, is the electrochemical control command, m is the number of intrinsic mode function components in the gravity control command, u k (t) is the kth intrinsic mode function component.

[0021] Furthermore, the power constraint and ramp rate constraint of the gravity energy storage subsystem are specifically expressed as:

[0022]

[0023] in, is the power of the gravity energy storage subsystem, is the gravity control command obtained at time t, μ is the climbing rate of the gravity energy storage subsystem, ΔP is the power change in the gravity energy storage subsystem within the interval time, and Δt is the interval time when the heavy block in the gravity energy storage subsystem is put into operation.

[0024] Furthermore, the output characteristics also include time constraints. The time constraints of the gravity energy storage subsystem are the time for putting a specific weight block into operation in a specific gravity energy storage unit given by combining the interval time for putting the weight block into operation, the number of gravity energy storage units in the gravity energy storage subsystem, and the number of weight blocks in the gravity energy storage subsystem.

[0025] Furthermore, the time constraint of the gravity energy storage subsystem is specifically expressed as:

[0026] t on_m,i =t on_1,1 +(i-1)·Δt+Δt·f(M)·(m-1)

[0027] Among them, t on_m,i is the input time of the ith weight block in the mth gravity energy storage unit, t on_1,1 is the time when the first weight block in the first gravity energy storage unit is put into operation, Δt is the interval time when the weight block is put into operation, f() is the mapping function, and M is the number of gravity energy storage units in the gravity energy storage subsystem.

[0028] Furthermore, the gravity power range is specifically expressed as:

[0029]

[0030] in, is the maximum power of the gravity energy storage subsystem at time t, is the minimum power of the gravity energy storage subsystem at time t, μ is the ramp rate of the gravity energy storage subsystem, Δt t-1 is the duration of the actual power of the gravity energy storage subsystem at time t-1, P Gra (t-1) is the actual power of the gravity energy storage subsystem at time t-1.

[0031] Furthermore, the gravity control instructions and gravity power range are compared, and the electrochemical power corresponding to the gravity control instructions is analyzed, including:

[0032] When the maximum power in the gravity power range is less than the gravity control instruction, the electrochemical power is determined as:

[0033]

[0034] When the minimum power in the gravity power range is greater than the gravity control instruction, the electrochemical power is determined as:

[0035]

[0036] Among them, P Bess (t) is the electrochemical power, For electrochemical control instructions, is the gravity control command, is the maximum power in the gravity power range, The minimum power in the gravity power range.

[0037] Furthermore, the working state of the hybrid energy storage system is specifically expressed as:

[0038] 0≤ω gra,c +ω gra,d ≤1

[0039] 0≤ω Bess,c +ω Bess,d ≤1

[0040] ω gra,c ·ω Bess,d +ω gra,d ·ω Bess,c =0

[0041] ω gra,c ,ω gra,d ∈{0,1}

[0042] ω Bess,c ,ω Bess,d ∈{0,1}

[0043] Among them, ω gra,c is the charging operation state of the gravity energy storage subsystem, ω gra,d is the discharge operation state of the gravity energy storage subsystem, ω Bess,c is the charging operation state of the electrochemical energy storage subsystem, ω Bess,d It is the discharge operation state of the electrochemical energy storage subsystem.

[0044] Furthermore, combined with the working state of the hybrid energy storage system, the total power range of the hybrid energy storage system is given, including:

[0045] When the hybrid energy storage system is in the discharging state, the total power range of the hybrid energy storage system is given, which is specifically expressed as:

[0046]

[0047] in, is the maximum power that the hybrid energy storage system can send to the power system at time t, is the minimum power that the hybrid energy storage system can send to the power system at time t, ω gra,d is the discharge operation state of the gravity energy storage subsystem in the hybrid energy storage system, is the maximum power of the gravity energy storage subsystem in the hybrid energy storage system under discharge state, is the minimum power of the gravity energy storage subsystem in the hybrid energy storage system in the discharge state, ω Bess,d is the discharge operation state of the electrochemical energy storage subsystem in the hybrid energy storage system, is the maximum power of the electrochemical energy storage subsystem in the hybrid energy storage system under discharge state, It is the minimum power of the electrochemical energy storage subsystem in the hybrid energy storage system under discharge state.

[0048] Furthermore, combined with the working state of the hybrid energy storage system, the total power range of the hybrid energy storage system is given, including:

[0049] When the hybrid energy storage system is in the charging state, the total power range of the hybrid energy storage system is given, which is specifically expressed as:

[0050]

[0051] in, is the maximum power that the hybrid energy storage system can absorb from the power system at time t, is the minimum power that the hybrid energy storage system can absorb from the power system at time t, ω gra,c is the charging operation status of the gravity energy storage subsystem in the hybrid energy storage system, is the maximum power of the gravity energy storage subsystem in the hybrid energy storage system under charging state, is the minimum power of the gravity energy storage subsystem in the hybrid energy storage system under charging state, ω Bess,c is the charging operation status of the electrochemical energy storage subsystem in the hybrid energy storage system, is the maximum power of the electrochemical energy storage subsystem in the hybrid energy storage system under charging state, It is the minimum power of the electrochemical energy storage subsystem in the hybrid energy storage system under charging state.

[0052] The present invention also discloses a power evaluation device for a hybrid energy storage system, comprising:

[0053] An instruction acquisition module, used to acquire a frequency modulation instruction of the power system, wherein the frequency modulation instruction includes a gravity control instruction for a gravity energy storage subsystem in the hybrid energy storage system and an electrochemical control instruction for an electrochemical energy storage subsystem in the hybrid energy storage system;

[0054] A gravity power determination module is used to provide a gravity power range corresponding to the frequency modulation instruction according to the output characteristics of the gravity energy storage subsystem, wherein the output characteristics include power constraints and ramp rate constraints of the gravity energy storage subsystem;

[0055] An electrochemical power determination module is used to compare the gravity control instruction and the gravity power range, and analyze the electrochemical power corresponding to the gravity control instruction;

[0056] The hybrid power determination module is used to provide a total power range of the hybrid energy storage system in combination with the working state of the hybrid energy storage system.

[0057] Furthermore, the frequency regulation command of the power system is determined by:

[0058] Obtaining the initial control signal from the power system;

[0059] Perform variational mode decomposition on the initial control signal to obtain n intrinsic mode function components;

[0060] The high frequency components among the n intrinsic mode function components are used as electrochemical control instructions, and the low frequency components among the n intrinsic mode function components are used as gravity control instructions.

[0061] Furthermore, the gravity control instruction and the electrochemical control instruction are specifically expressed as:

[0062]

[0063] in, is the gravity control command, is the electrochemical control command, m is the number of intrinsic mode function components in the gravity control command, u k (t) is the kth intrinsic mode function component.

[0064] Furthermore, the power constraint and ramp rate constraint of the gravity energy storage subsystem are specifically expressed as:

[0065]

[0066] in, is the power of the gravity energy storage subsystem, is the gravity control command obtained at time t, μ is the climbing rate of the gravity energy storage subsystem, ΔP is the power change in the gravity energy storage subsystem within the interval time, and Δt is the interval time when the heavy block in the gravity energy storage subsystem is put into operation.

[0067] Furthermore, the output characteristics also include time constraints. The time constraints of the gravity energy storage subsystem are the time for putting a specific weight block into operation in a specific gravity energy storage unit given by combining the interval time for putting the weight block into operation, the number of gravity energy storage units in the gravity energy storage subsystem, and the number of weight blocks in the gravity energy storage subsystem.

[0068] Furthermore, the time constraint of the gravity energy storage subsystem is specifically expressed as:

[0069] t on_m,i =t on_1,1 +(i-1)·Δt+Δt·f(M)·(m-1)

[0070] Among them, t on_m,i is the input time of the i-th weight block in the m-th gravity energy storage unit, t on_1,1 is the time when the first weight block in the first gravity energy storage unit is put into operation, Δt is the interval time when the weight block is put into operation, f() is the mapping function, and M is the number of gravity energy storage units in the gravity energy storage subsystem.

[0071] Furthermore, the gravity power range is specifically expressed as:

[0072]

[0073] in, is the maximum power of the gravity energy storage subsystem at time t, is the minimum power of the gravity energy storage subsystem at time t, μ is the ramp rate of the gravity energy storage subsystem, Δt t-1 is the duration of the actual power of the gravity energy storage subsystem at time t-1, P Gra (t-1) is the actual power of the gravity energy storage subsystem at time t-1.

[0074] Furthermore, the gravity control instructions and gravity power range are compared, and the electrochemical power corresponding to the gravity control instructions is analyzed, including:

[0075] When the maximum power in the gravity power range is less than the gravity control instruction, the electrochemical power is determined as:

[0076]

[0077] When the minimum power in the gravity power range is greater than the gravity control instruction, the electrochemical power is determined as:

[0078]

[0079] Among them, P Bess (t) is the electrochemical power, For electrochemical control instructions, is the gravity control command, is the maximum power in the gravity power range, The minimum power in the gravity power range.

[0080] Furthermore, the working state of the hybrid energy storage system is specifically expressed as:

[0081] 0≤ω gra,c +ω gra,d ≤1

[0082] 0≤ω Bess,c +ω Bess,d ≤1

[0083] ω gra,c ·ω Bess,d +ω gra,d ·ω Bess,c =0

[0084] ω gra,c ,ω gra,d ∈{0,1}

[0085] ω Bess,c ,ω Bess,d ∈{0,1}

[0086] Among them, ω gra,c is the charging operation state of the gravity energy storage subsystem, ω gra,d is the discharge operation state of the gravity energy storage subsystem, ω Bess,c is the charging operation state of the electrochemical energy storage subsystem, ω Bess,d It is the discharge operation state of the electrochemical energy storage subsystem.

[0087] Furthermore, combined with the working state of the hybrid energy storage system, the total power range of the hybrid energy storage system is given, including:

[0088] When the hybrid energy storage system is in the discharging state, the total power range of the hybrid energy storage system is given, which is specifically expressed as:

[0089]

[0090] in, is the maximum power that the hybrid energy storage system can send to the power system at time t, is the minimum power that the hybrid energy storage system can send to the power system at time t, ω gra,d is the discharge operation state of the gravity energy storage subsystem in the hybrid energy storage system, is the maximum power of the gravity energy storage subsystem in the hybrid energy storage system under discharge state, is the minimum power of the gravity energy storage subsystem in the hybrid energy storage system in the discharge state, ω Bess,d is the discharge operation state of the electrochemical energy storage subsystem in the hybrid energy storage system, is the maximum power of the electrochemical energy storage subsystem in the hybrid energy storage system under discharge state, It is the minimum power of the electrochemical energy storage subsystem in the hybrid energy storage system under discharge state.

[0091] Furthermore, combined with the working state of the hybrid energy storage system, the total power range of the hybrid energy storage system is given, including:

[0092] When the hybrid energy storage system is in the charging state, the total power range of the hybrid energy storage system is given, which is specifically expressed as:

[0093]

[0094] in, is the maximum power that the hybrid energy storage system can absorb from the power system at time t, is the minimum power that the hybrid energy storage system can absorb from the power system at time t, ω gra,c is the charging operation status of the gravity energy storage subsystem in the hybrid energy storage system, is the maximum power of the gravity energy storage subsystem in the hybrid energy storage system under charging state, is the minimum power of the gravity energy storage subsystem in the hybrid energy storage system under charging state, ω Bess,c is the charging operation status of the electrochemical energy storage subsystem in the hybrid energy storage system, is the maximum power of the electrochemical energy storage subsystem in the hybrid energy storage system under charging state, It is the minimum power of the electrochemical energy storage subsystem in the hybrid energy storage system under charging state.

[0095] The power evaluation method and device of the hybrid energy storage system provided by the present invention have at least the following beneficial effects:

[0096] By timely obtaining the frequency modulation instructions issued by the power system, the gravity power range is determined according to the frequency modulation instructions and the output characteristics of the gravity energy storage subsystem, and the electrochemical power is determined based on this, and finally the total power range of the hybrid energy storage system under different working conditions is obtained.

[0097] According to the frequency modulation instructions that can reflect the actual needs of the power system, the gravity power range and the electrochemical power are determined in turn, and finally the total power range of the hybrid energy storage system is obtained, which improves the accuracy of the power evaluation of the hybrid energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0098] Figure 1 A flow chart of a power evaluation method for a hybrid energy storage system provided by an embodiment of the present invention;

[0099] Figure 2 A flow chart for determining a frequency modulation instruction provided by an embodiment of the present invention;

[0100] Figure 3 A structural diagram of a power evaluation device for a hybrid energy storage system provided in an embodiment of the present invention.

[0101] Among them, 201 is an instruction acquisition module; 202 is a gravity power determination module; 203 is an electrochemical power determination module; 204 is a hybrid power determination module. DETAILED DESCRIPTION

[0102] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0103] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0104] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0105] Gravity energy storage is a long-term energy storage technology. Due to its own mechanical structure limitations, the output power characteristics of gravity energy storage present a step-like characteristic. The dynamic adjustment process of gravity energy storage output is greatly affected by the initial load. The response time of high-power load increase and low-power load reduction is long and uncertain, and the adjustment rate is greatly affected.

[0106] Gravity energy storage has a fixed time interval for the insertion of heavy blocks. A single gravity energy storage device is difficult to meet the real-time power demand of the power system, while the power of electrochemical energy storage can achieve smooth and continuous output. The configuration of electrochemical energy storage is of great significance for improving the response time and regulation performance of gravity energy storage under different operating modes. The integration of gravity energy storage and electrochemical energy storage can achieve power and energy complementarity, improve the comprehensive regulation performance of the power station, and meet the operation requirements of the power system.

[0107] At present, the research on the integration of various energy storage forms mainly focuses on hybrid energy storage power stations in various forms such as flywheel and electrochemistry, supercapacitor and electrochemistry, etc., to achieve the complementarity of power-type and energy-type energy storage so that it has the characteristics of high power and high energy efficiency, and meet the peak and frequency regulation needs under complex working conditions of the power system.

[0108] Therefore, the research on hybrid energy storage systems including gravity energy storage and electrochemical energy storage has not yet been involved. How to accurately evaluate the power of the hybrid energy storage system composed of gravity energy storage and electrochemical energy storage is a problem that needs to be solved at present.

[0109] like Figure 1 As shown, the present invention provides a power evaluation method for a hybrid energy storage system, and the specific steps are as follows:

[0110] S101: Obtain frequency regulation instructions of the power system.

[0111] Specifically, the frequency modulation instructions include gravity control instructions for the gravity energy storage subsystem in the hybrid energy storage system and electrochemical control instructions for the electrochemical energy storage subsystem in the hybrid energy storage system.

[0112] Furthermore, the frequency regulation command of the power system is determined by:

[0113] Reference Figure 2 , obtain the initial control signal issued by the power system. Perform variational modal decomposition on the initial control signal to obtain n intrinsic modal function components. The high-frequency components in the n intrinsic modal function components are used as electrochemical control instructions, and the low-frequency components in the n intrinsic modal function components are used as gravity control instructions.

[0114] It should be understood that when the power system needs to be combined with a hybrid energy storage system for power distribution, the power system will issue an initial control signal. The initial control signal is subjected to variational mode decomposition to obtain n intrinsic mode function components. The n intrinsic mode function components are sorted in ascending or descending order according to the frequency, and the high-frequency components are reconstructed to obtain the electrochemical control instructions of the electrochemical energy storage subsystem. The low-frequency components are reconstructed to obtain the gravity control instructions of the gravity energy storage subsystem In a specific example, the n intrinsic mode function components are sorted in ascending order, and the gravity control instruction and the electrochemical control instruction are specifically expressed as:

[0115]

[0116] In the formula, is the gravity control command, is the electrochemical control command, m is the number of intrinsic mode function components in the gravity control command, u k (t) is the kth intrinsic mode function component. The first m intrinsic mode function components among the sorted n intrinsic mode function components are reconstructed to obtain the gravity control instruction, and the m+1th intrinsic mode function component to the nth intrinsic mode function component among the sorted n intrinsic mode function components are reconstructed to obtain the electrochemical control instruction.

[0117] Variational mode decomposition (VMD) is an adaptive signal processing technique used to decompose a signal into several modal components. This method aims to overcome the modal aliasing phenomenon in the empirical mode decomposition method. VMD determines the center frequency and bandwidth of each component by iteratively searching for the optimal solution of the variational model, thereby achieving frequency domain decomposition of the signal and effective separation of each component.

[0118] VMD decomposes the original signal into multiple modal components, each with a center frequency and a finite bandwidth. VMD finds the optimal center frequency and bandwidth of these modal components by optimizing the variational problem, so that the sum of the estimated bandwidths of each mode is minimized, while satisfying the constraint that the sum of all modes is equal to the original signal.

[0119] VMD can automatically determine the number of modal decompositions according to the actual situation of the signal, and adaptively match the optimal center frequency and limited bandwidth of each mode; it shows strong robustness in sampling and noise, and is suitable for processing non-stationary signals; and it can reduce the non-stationarity of time series with high complexity and strong nonlinearity.

[0120] S102: According to the output characteristics of the gravity energy storage subsystem, a gravity power range corresponding to the frequency modulation instruction is given.

[0121] Specifically, the output characteristics include power constraints and ramp rate constraints of the gravity energy storage subsystem.

[0122] In order to meet the frequency modulation requirements corresponding to the frequency modulation instructions, the power of the gravity energy storage subsystem and the electrochemical energy storage subsystem should meet their corresponding power constraints, which can be specifically expressed as:

[0123]

[0124]

[0125] In the formula, is the power of the gravity energy storage subsystem, is the gravity control command obtained at time t, is the power of the electrochemical energy storage subsystem, is the electrochemical control instruction obtained at time t.

[0126] The climbing rate constraint of the gravity energy storage subsystem is specifically expressed as:

[0127]

[0128] Among them, μ is the climbing rate of the gravity energy storage subsystem, ΔP is the power change in the gravity energy storage subsystem within the interval time, and Δt is the interval time when the heavy object block in the gravity energy storage subsystem is put into operation.

[0129] The climbing rate of the gravity energy storage unit is the variation range of the output power of the gravity energy storage unit per unit time. The climbing rate constraint of the gravity energy storage unit in the gravity energy storage subsystem is limited by the time when the weight block in the gravity energy storage subsystem is put into operation.

[0130] Due to the physical characteristics of the gravity energy storage unit in the gravity energy storage subsystem, there is a fixed time interval between the input and output of each weight block, which will directly affect the ramp rate of the gravity energy storage unit in the gravity energy storage subsystem. The input time of each weight block is measured by the time interval, and the time constraint for the input of each weight block is specifically expressed as:

[0131] t on_i =t on_1 +(i-1)Δt

[0132] Where i is the number of the weight block in the gravity energy storage subsystem, t on_1 is the time when the first weight block in the gravity energy storage subsystem is put into operation, t on_i is the time when the i-th weight block in the gravity energy storage subsystem is put into operation, Δt is the interval time when the weight blocks in the gravity energy storage subsystem are put into operation, and the time when the weight blocks in the gravity energy storage subsystem are put into operation is used to reflect the climbing rate of the gravity energy storage subsystem.

[0133] The gravity energy storage subsystem in the present invention includes multiple gravity energy storage units, each of which includes multiple weight blocks. In order to avoid a large power impact on the power system caused by the simultaneous input of multiple weight blocks, a control strategy is preset. By reasonably arranging the order and time of the input of the weight blocks, the power output of the gravity energy storage subsystem to the power system is optimized, and the stability and response efficiency of the power system are improved.

[0134] The preset control strategy is that the weight blocks in each gravity energy storage unit have a predetermined time to be put into operation to ensure that they are not put into operation at the same time.

[0135] That is, the output characteristics of the gravity energy storage subsystem also include time constraints. The time constraints of the gravity energy storage subsystem are the time for putting a specific weight block into operation in a specific gravity energy storage unit given by combining the interval time for putting the weight block into operation, the number of gravity energy storage units in the gravity energy storage subsystem, and the number of weight blocks in the gravity energy storage subsystem.

[0136] The time constraint of the gravity energy storage subsystem is specifically expressed as:

[0137] t on_m，i =t on_1，1 +(i-1)·Δt+Δt·f(M)·(m-1)

[0138] Among them, t on_m，i is the input time of the i-th weight block in the m-th gravity energy storage unit, t on_1，1 is the time when the first weight block in the first gravity energy storage unit is put into operation, Δt is the interval time when the weight block is put into operation, f() is the mapping function, and M is the number of gravity energy storage units in the gravity energy storage subsystem.

[0139] Among them, f(M) is a mapping function related to the number of gravity energy storage units in the gravity energy storage subsystem. The type of mapping function can be preset, which can be a multiple relationship, a monomial, or a polynomial. No further limitation is made here.

[0140] The weight blocks of each gravity energy storage unit will be put into the power system at a time point calculated according to the above time constraints, thereby achieving a gradual increase in power and avoiding sudden and large changes in power.

[0141] For example, in one embodiment, the vertical matrix gravity energy storage system has three gravity energy storage units (M=3), each of which has four weight blocks. If the first weight block of the first gravity energy storage unit is at t on_1，1 = 0s, and the interval time Δt of the weight block input is 10s. f(M) and M are monomials. f(M) is 2. Then the time of the weight block input is as follows:

[0142] The first weight block of gravity energy storage unit 1: t on_1，1 = 0s;

[0143] The second weight block of gravity energy storage unit 1: t on_1，2 =10s;

[0144] Similarly, the first weight block of gravity energy storage unit 2: t on_2，1 =20s;

[0145] The second weight block of gravity energy storage unit 2: t on_2，1 =30s.

[0146] In this way, the input of each weight block of each gravity energy storage unit is orderly and dispersed in time, thereby reducing the power shock to the power system and improving the responsiveness and stability of the power system.

[0147] The gravity power range is specifically expressed as:

[0148]

[0149] in, is the maximum power of the gravity energy storage subsystem at time t, is the minimum power of the gravity energy storage subsystem at time t, μ is the ramp rate of the gravity energy storage subsystem, Δt t-1 is the duration of the actual power of the gravity energy storage subsystem at time t-1, P Gra (t-1) is the actual power of the gravity energy storage subsystem at time t-1.

[0150] S103: Compare the gravity control instruction and the gravity power range, and analyze the electrochemical power corresponding to the gravity control instruction.

[0151] Specifically, when the maximum power in the gravity power range is less than the gravity control instruction, the electrochemical power is determined as:

[0152]

[0153] When the minimum power in the gravity power range is greater than the gravity control instruction, the electrochemical power is determined as:

[0154]

[0155] Among them, P Bess (t) is the electrochemical power, For electrochemical control instructions, is the gravity control command, is the maximum power in the gravity power range, The minimum power in the gravity power range.

[0156] It should be understood that due to the certain losses in the energy storage equipment and the converter equipment during the process of storing and releasing electrical energy in the electrochemical energy storage subsystem, and considering the rapid response characteristics of the electrochemical energy storage subsystem, since the response time of the electrochemical energy storage subsystem is much shorter than that of the gravity energy storage subsystem, the electrochemical energy storage subsystem first responds quickly to the electrochemical control instructions to ensure the frequency modulation effect. As the output of the gravity energy storage subsystem gradually increases, the electrochemical energy storage subsystem begins to reduce power to ensure that the total power of the hybrid energy storage system remains consistent with the target power.

[0157] S104: Based on the working state of the hybrid energy storage system, a total power range of the hybrid energy storage system is given.

[0158] Specifically, when the working state of the hybrid energy storage system is the discharge state, the total power range of the hybrid energy storage system is given, which is specifically expressed as:

[0159]

[0160] in, is the maximum power that the hybrid energy storage system can send to the power system at time t, is the minimum power that the hybrid energy storage system can send to the power system at time t, ω gra,d is the discharge operation state of the gravity energy storage subsystem in the hybrid energy storage system, is the maximum power of the gravity energy storage subsystem in the hybrid energy storage system under discharge state, is the minimum power of the gravity energy storage subsystem in the hybrid energy storage system in the discharge state, ω Bess,d is the discharge operation state of the electrochemical energy storage subsystem in the hybrid energy storage system, is the maximum power of the electrochemical energy storage subsystem in the hybrid energy storage system under discharge state, It is the minimum power of the electrochemical energy storage subsystem in the hybrid energy storage system under discharge state.

[0161] When the hybrid energy storage system is in the charging state, the total power range of the hybrid energy storage system is given, which is specifically expressed as:

[0162]

[0163] in, is the maximum power that the hybrid energy storage system can absorb from the power system at time t, is the minimum power that the hybrid energy storage system can absorb from the power system at time t, ω gra,c is the charging operation status of the gravity energy storage subsystem in the hybrid energy storage system, is the maximum power of the gravity energy storage subsystem in the hybrid energy storage system under charging state, is the minimum power of the gravity energy storage subsystem in the hybrid energy storage system under charging state, ω Bess,c is the charging operation status of the electrochemical energy storage subsystem in the hybrid energy storage system, is the maximum power of the electrochemical energy storage subsystem in the hybrid energy storage system under charging state, It is the minimum power of the electrochemical energy storage subsystem in the hybrid energy storage system under charging state.

[0164] It should be understood that according to the topological structure of the hybrid energy storage system, when the power system sends the initial control signal, the operating state of the gravity energy storage subsystem should be consistent with the operating state of the electrochemical energy storage subsystem, that is, both are in the discharge state or the charging state at the same time. The working state of the hybrid energy storage system is specifically expressed as:

[0165] 0≤ω gra,c +ω gra,d ≤1

[0166] 0≤ω Bess,c +ω Bess,d ≤1

[0167] ω gra,c ·ω Bess,d +ω gra,d ·ω Bess,c =0

[0168] ω gra,c ,ω gra,d ∈{0,1}

[0169] ω Bess,c ,ω Bess,d ∈{0,1}

[0170] Among them, ω gra,c is the charging operation state of the gravity energy storage subsystem, ω gra,d is the discharge operation state of the gravity energy storage subsystem, ω Bess,c is the charging operation state of the electrochemical energy storage subsystem, ω Bess,d It is the discharge operation state of the electrochemical energy storage subsystem.

[0171] When gra,c =1, indicating that the gravity energy storage subsystem is operating in the charging state. gra,c =0, it means that the gravity energy storage subsystem is not operating in the charging state; when ω gra,d =1, indicating that the gravity energy storage subsystem is operating in the discharge state. gra,d = 0, it means that the gravity energy storage subsystem is not operating in the discharge state. Bess,c=1, indicating that the electrochemical energy storage subsystem is operating in the charging state. Bess,c = 0, indicating that the electrochemical energy storage subsystem is not operating in a charging state. Bess,d =1, indicating that the electrochemical energy storage subsystem is operating in the discharge state. Bess,d =0, the electrochemical energy storage subsystem is not operating in a discharge state.

[0172] Reference Figure 3 , an embodiment of the present invention provides a power evaluation device for a hybrid energy storage system, comprising:

[0173] The instruction acquisition module 201 is used to acquire the frequency modulation instruction of the power system, wherein the frequency modulation instruction includes the gravity control instruction for the gravity energy storage subsystem in the hybrid energy storage system and the electrochemical control instruction for the electrochemical energy storage subsystem in the hybrid energy storage system;

[0174] The gravity power determination module 202 is used to provide a gravity power range corresponding to the frequency modulation instruction according to the output characteristics of the gravity energy storage subsystem, wherein the output characteristics include the power constraint and the climbing rate constraint of the gravity energy storage subsystem;

[0175] The electrochemical power determination module 203 is used to compare the gravity control instruction with the gravity power range and analyze the electrochemical power corresponding to the gravity control instruction;

[0176] The hybrid power determination module 204 is used to provide a total power range of the hybrid energy storage system in combination with the working state of the hybrid energy storage system.

[0177] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process of the described module can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0178] The power evaluation method and device of the hybrid energy storage system provided by the present invention have at least the following beneficial effects:

[0179] By timely obtaining the frequency modulation instructions issued by the power system, the gravity power range is determined according to the frequency modulation instructions and the output characteristics of the gravity energy storage subsystem, and the electrochemical power is determined based on this, and finally the total power range of the hybrid energy storage system under different working conditions is obtained.

[0180] According to the frequency modulation instructions that can reflect the actual needs of the power system, the gravity power range and the electrochemical power are determined in turn, and finally the total power range of the hybrid energy storage system is obtained, which improves the accuracy of the power evaluation of the hybrid energy storage system.

[0181] It should be noted that the computer-readable medium of the present disclosure may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present disclosure, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer readable signal medium may also be any computer readable medium other than a computer readable storage medium, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0182] The computer-readable medium may be included in the electronic device, or may exist independently without being installed in the electronic device.

[0183] Computer program code for performing the operations of the present disclosure may be written in one or more programming languages, or a combination thereof, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., through the Internet using an Internet service provider).

[0184] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or the flowchart, and the combination of boxes in the block diagram and / or the flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0185] The units involved in the embodiments described in the present disclosure may be implemented by software or hardware, wherein the name of a unit does not, in some cases, limit the unit itself.

[0186] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A power evaluation method for a hybrid energy storage system, characterized in that: include: Obtaining a frequency modulation instruction of the power system, wherein the frequency modulation instruction includes a gravity control instruction for a gravity energy storage subsystem in the hybrid energy storage system and an electrochemical control instruction for an electrochemical energy storage subsystem in the hybrid energy storage system; According to the output characteristics of the gravity energy storage subsystem, the gravity power range corresponding to the frequency modulation instruction is given, wherein the output characteristics include the power constraint and the ramp rate constraint of the gravity energy storage subsystem; Compare the gravity control instructions and gravity power range, and analyze the electrochemical power corresponding to the gravity control instructions; Combined with the working state of the hybrid energy storage system, the total power range of the hybrid energy storage system is given.

2. The power evaluation method of the hybrid energy storage system according to claim 1, characterized in that: The frequency regulation command of the power system is determined by: Obtaining the initial control signal from the power system; Perform variational mode decomposition on the initial control signal to obtain n intrinsic mode function components; The high frequency components among the n intrinsic mode function components are used as electrochemical control instructions, and the low frequency components among the n intrinsic mode function components are used as gravity control instructions.

3. The power evaluation method of the hybrid energy storage system according to claim 2, characterized in that: The gravity control instructions and electrochemical control instructions are specifically expressed as: in, is the gravity control command, is the electrochemical control command, m is the number of intrinsic mode function components in the gravity control command, u k (t) is the kth intrinsic mode function component.

4. The power evaluation method of the hybrid energy storage system according to claim 1, characterized in that: The power constraint and ramp rate constraint of the gravity energy storage subsystem are specifically expressed as: in, is the power of the gravity energy storage subsystem, is the gravity control command obtained at time t, μ is the climbing rate of the gravity energy storage subsystem, ΔP is the power change in the gravity energy storage subsystem within the interval time, and Δt is the interval time when the heavy block in the gravity energy storage subsystem is put into operation.

5. The power evaluation method of the hybrid energy storage system according to claim 4, characterized in that: The gravity power range is specifically expressed as: in, is the maximum power of the gravity energy storage subsystem at time t, is the minimum power of the gravity energy storage subsystem at time t, μ is the ramp rate of the gravity energy storage subsystem, Δt t-1 is the duration of the actual power of the gravity energy storage subsystem at time t-1, P Gra (t-1) is the actual power of the gravity energy storage subsystem at time t-1.

6. The power evaluation method of the hybrid energy storage system according to claim 1, characterized in that: The comparing the gravity control instruction and the gravity power range and analyzing the electrochemical power corresponding to the gravity control instruction includes: When the maximum power in the gravity power range is less than the gravity control instruction, the electrochemical power is determined as: When the minimum power in the gravity power range is greater than the gravity control instruction, the electrochemical power is determined as: Among them, P Bess (t) is the electrochemical power, For electrochemical control instructions, is the gravity control command, is the maximum power in the gravity power range, The minimum power in the gravity power range.

7. The power evaluation method of the hybrid energy storage system according to claim 1, characterized in that: The working state of the hybrid energy storage system is specifically expressed as: 0≤ω gra,c +oh gra,d ≤1 0≤ω Bess,c +oh Bess,d ≤1 oh gra,c ·oh Bess,d +oh gra,d ·oh Bess,c =0 oh gra,c ,oh gra,d ∈{0,1} oh Bess,c ,oh Bess,d ∈{0,1} Among them, ω gra,c is the charging operation state of the gravity energy storage subsystem, ω gra,d is the discharge operation state of the gravity energy storage subsystem, ω Bess,c is the charging operation state of the electrochemical energy storage subsystem, ω Bess,d It is the discharge operation state of the electrochemical energy storage subsystem.

8. The power evaluation method of the hybrid energy storage system according to claim 7, characterized in that: Combined with the working state of the hybrid energy storage system, the total power range of the hybrid energy storage system is given, including: When the hybrid energy storage system is in the discharging state, the total power range of the hybrid energy storage system is given, which is specifically expressed as: in, is the maximum power that the hybrid energy storage system can send to the power system at time t, is the minimum power that the hybrid energy storage system can send to the power system at time t, ω gra,d is the discharge operation state of the gravity energy storage subsystem in the hybrid energy storage system, is the maximum power of the gravity energy storage subsystem in the hybrid energy storage system under discharge state, is the minimum power of the gravity energy storage subsystem in the hybrid energy storage system in the discharge state, ω Bess,d is the discharge operation state of the electrochemical energy storage subsystem in the hybrid energy storage system, is the maximum power of the electrochemical energy storage subsystem in the hybrid energy storage system under discharge state, It is the minimum power of the electrochemical energy storage subsystem in the hybrid energy storage system under discharge state.

9. The power evaluation method of the hybrid energy storage system according to claim 7, characterized in that: Combined with the working state of the hybrid energy storage system, the total power range of the hybrid energy storage system is given, including: When the hybrid energy storage system is in the charging state, the total power range of the hybrid energy storage system is given, which is specifically expressed as: in, is the maximum power that the hybrid energy storage system can absorb from the power system at time t, is the minimum power that the hybrid energy storage system can absorb from the power system at time t, ω gra,c is the charging operation status of the gravity energy storage subsystem in the hybrid energy storage system, is the maximum power of the gravity energy storage subsystem in the hybrid energy storage system under charging state, is the minimum power of the gravity energy storage subsystem in the hybrid energy storage system under charging state, ω Bess,c is the charging operation status of the electrochemical energy storage subsystem in the hybrid energy storage system, is the maximum power of the electrochemical energy storage subsystem in the hybrid energy storage system under charging state, It is the minimum power of the electrochemical energy storage subsystem in the hybrid energy storage system under charging state.

10. A power evaluation device for a hybrid energy storage system, characterized in that: A power evaluation method for a hybrid energy storage system according to any one of claims 1 to 9, comprising: An instruction acquisition module, used to acquire a frequency modulation instruction of the power system, wherein the frequency modulation instruction includes a gravity control instruction for a gravity energy storage subsystem in the hybrid energy storage system and an electrochemical control instruction for an electrochemical energy storage subsystem in the hybrid energy storage system; A gravity power determination module is used to provide a gravity power range corresponding to the frequency modulation instruction according to the output characteristics of the gravity energy storage subsystem, wherein the output characteristics include power constraints and ramp rate constraints of the gravity energy storage subsystem; An electrochemical power determination module is used to compare the gravity control instruction and the gravity power range, and analyze the electrochemical power corresponding to the gravity control instruction; The hybrid power determination module is used to provide a total power range of the hybrid energy storage system in combination with the working state of the hybrid energy storage system.

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