A large-capacity electrolytic cell electromechanical transient modeling method considering topological relation matrix

Abstract

The application provides a large-capacity electrolytic cell electromechanical transient modeling method considering a topological relation matrix, including the following steps: for a power grid and a load configuration structure under a given scene, a topological relation matrix between an electrolytic cell array, an auxiliary system and an electric energy conversion system is constructed, and a system coordinated operation model is established; a large-capacity water electrolytic cell unit and an electrolytic cell auxiliary system are modeled, and a hydrogen production system operation model is obtained; the electric energy conversion system is modeled and installed in parallel with the grid, and forms a grid-connected system together with the integrated electrolytic cell system; a control strategy under multiple constraint conditions is considered, and the ability of the electrolytic cell to respond to power grid dispatching is improved; and the method provided by the application can solve the problem that the current hydrogen production system cannot linearly expand the coupling relationship between the unit array and the power distribution system in a sufficient and rapid manner.

Description

Technical Field

[0001] This invention belongs to the field of wind power hydrogen production technology, specifically relating to a method for electromechanical transient modeling of large-capacity electrolyzers that considers topological relationship matrices. Background Technology

[0002] Hydrogen energy is a recognized clean energy carrier, characterized by high energy density, high conversion efficiency, zero pollution, and zero carbon emissions, making it one of the most promising energy sources. Coupled hydrogen production with renewable energy sources such as wind power can not only leverage hydrogen's advantages in energy storage and rapid power regulation, reducing the instability of grid integration with high proportions of renewable energy and increasing the utilization hours of renewable energy generation, but also fully utilize wind and solar power curtailment, improving the economics of hydrogen production from wind and solar power. In the context of the "dual-carbon" era, utilizing renewable energy sources such as wind power for hydrogen production will undoubtedly be an important research topic for future energy development.

[0003] Hydrogen production technology is an important energy technology that produces high-purity hydrogen by electrolyzing water to separate it into hydrogen and oxygen. The hydrogen electrolyzer is a key component of hydrogen production equipment, significantly impacting efficiency and energy consumption, and is widely used in the hydrogen energy industry. Currently, traditional hydrogen electrolyzer designs typically employ empirical formulas and static modeling methods to simulate the gas-liquid fluid dynamics and electrochemical reactions within the cell. However, this static modeling approach cannot accurately describe the dynamic processes within the electrolyzer, leading to a degree of uncertainty and trial-and-error in the design and optimization process. Furthermore, current simulation analysis methods for hydrogen electrolyzers are primarily based on traditional mathematical models, which are complex and computationally intensive, and current hydrogen production systems cannot fully and quickly coordinate the coupling relationship between the unit array and the power distribution system for linear scaling. Therefore, a dynamic simulation modeling method for hydrogen electrolyzers is needed to accurately simulate the coupling relationship between the electrolyzer unit array and the power distribution system, rapidly obtain dynamic information on system physical parameters, and improve the efficiency and energy utilization of hydrogen production equipment. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for electromechanical transient modeling of large-capacity electrolyzers considering topological relationship matrices. This method establishes a comprehensive electrolyzer model capable of describing the hydrogen production characteristics, temperature and pressure variations, mass transport, energy conversion, thermodynamic characteristics of auxiliary systems, alkali circulation, and hydrogen compression and storage. The invention will now be clearly and completely described in conjunction with the accompanying drawings and specific examples. It should be noted that the described embodiments are only some, not all, of the embodiments of this invention, and this invention is not intended to limit its use or purpose.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for electromechanical transient modeling of large-capacity electrolytic cells considering topological relationship matrices, specifically including:

[0007] Based on the power grid and load configuration structure, establish a topological relationship matrix between the electrolytic cell array, auxiliary equipment system, and power conversion system;

[0008] Considering power, hydrogen balance and various equipment constraints, a model is created for the large-capacity water electrolyzer unit and auxiliary system to obtain an integrated electrolyzer system operation model.

[0009] Based on the overload characteristics and initial capacity of the integrated electrolytic cell system, the power conversion system is modeled and grid-connected, resulting in a grid-connected system model.

[0010] Based on the equipment operating threshold and combined with the bus voltage and the dynamic characteristics of the electrolytic cell, a control strategy for the electrolytic cell system under multiple constraints is proposed.

[0011] Beneficial effects:

[0012] This invention provides a dynamic simulation modeling method for hydrogen production electrolyzers, which simplifies the mathematical model of the hydrogen production electrolyzer, accurately describes the dynamic process inside the electrolyzer, accurately simulates the coupling relationship between the electrolyzer unit array and the power distribution system, quickly obtains dynamic information on system physical parameters, and improves the efficiency and energy utilization of hydrogen production equipment. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of an electrolytic cell model and a power grid interface proposed in this invention;

[0014] Figure 2 This is a schematic diagram of an auxiliary system model that is matched with an electrolytic cell, as proposed in this invention.

[0015] Figure 3a This is a parallel Buck circuit topology diagram in an energy conversion system proposed in this invention;

[0016] Figure 3b This invention provides an equivalent circuit for a symmetrical resonant dual active bridge converter.

[0017] Figure 4a This is a block diagram of an electrolytic cell temperature control proposed in this invention;

[0018] Figure 4b This is a block diagram of an electrolytic cell pressure control proposed in this invention;

[0019] Figure 4c This invention proposes a control strategy for power constraints based on hydrogen reserves.

[0020] Figure 4d This is a block diagram of an electrolytic cell power control proposed in this invention. Detailed Implementation

[0021] This invention primarily addresses the problem of complex and computationally intensive electromechanical transient modeling methods for hydrogen production electrolyzers. Furthermore, it addresses the issue that hydrogen production systems cannot fully and quickly coordinate the coupling relationship between the unit array and the power distribution system for linear expansion. Therefore, this invention proposes a large-capacity electromechanical transient modeling method that considers the topological relationship matrix.

[0022] The present invention provides a method for electromechanical transient modeling of large-capacity electrolytic cells considering topological relationship matrices, specifically comprising:

[0023] Based on the power grid and load configuration structure, establish a topological relationship matrix between the electrolytic cell array, auxiliary equipment system, and power conversion system;

[0024] Considering power, hydrogen balance and various equipment constraints, a model is created for the large-capacity water electrolyzer unit and auxiliary system to obtain an integrated electrolyzer system operation model.

[0025] Based on the overload characteristics and initial capacity of the integrated electrolytic cell system, the power conversion system is modeled and grid-connected, resulting in a grid-connected system model.

[0026] Based on the equipment operating threshold and combined with the bus voltage and the dynamic characteristics of the electrolytic cell, a control strategy for the electrolytic cell system under multiple constraints is proposed.

[0027] First, this invention provides an interface model for an electrolytic cell and a power grid, see... Figure 1 Including the electrolytic reactor reverse voltage U rev Internal resistance R i Including double electric layer branch (EDL), the model can accurately reflect the energy exchange relationship between the electrolyzer and the power grid.

[0028] The electrolytic reactor model is based on the electrolytic reactor inverse voltage U. rev Internal resistance R i and the double electrical layer branch EDL (this branch has a transmission resistance R) m and overpotential capacitance C op The composition can be obtained by fitting the polarization curve / response curve of the measurement experiment.

[0029]

[0030] Among them, U rev and R i It is the electrolytic cell pressure p el and temperature T el The function. E rev0 and R i0 Let T0 be the initial values ​​of the reverse voltage and internal resistance at temperature T0 and pressure p0, k be the parameters of the fitted curve, C be the temperature coefficient of resistance, and F be the Faraday constant.

[0031] Furthermore, the topology relationship establishment module specifically includes:

[0032] First, the electrolytic cells, auxiliary systems, and power conversion systems in a given scenario are numbered. (Assume the number of electrolytic cells in the given topology is m, the number of auxiliary systems is n, and the number of power conversion systems is k). The electrolytic cell sequence is numbered 1, 2, 3, ..., m; the auxiliary system sequence is numbered 1, 2, 3, ..., n; and the power conversion system sequence is numbered 1, 2, 3, ..., k.

[0033] Then, according to the topological correspondence between the electrolytic cell, auxiliary system and power conversion system in the given scenario, topological relationship matrices A, B and C are established between the electrolytic cell sequence, auxiliary system sequence and power conversion system sequence, respectively.

[0034] Assuming there are m auxiliary systems and n electrolytic cells, we can construct an m x n matrix where each element is a binary value representing a correspondence. For example, if auxiliary system 1 needs to be paired with electrolytic cell 2, then the element in the first row and second column of the relationship matrix is ​​1, and the elements in the remaining rows and columns are 0.

[0035] The relationship matrix A between the electrolytic cell array and the auxiliary system array is established as follows:

[0036]

[0037] The relationship matrix B between the power conversion system sequence and the electrolyzer sequence is established as follows:

[0038]

[0039] The relationship matrix C between the power conversion system sequence and the auxiliary system sequence is established as follows:

[0040]

[0041] Furthermore, in the model building module, the system model specifically includes: an electrochemical model, a mass transport model, and an energy conversion model;

[0042] The established electrochemical model for a single-unit water electrolyzer is as follows:

[0043] For a bipolar electrolytic cell, the total voltage U of the electrolytic cell el The voltage U of a single electrolysis cell cell The sum is calculated as follows:

[0044] U el =N cell U cell

[0045] Where: N cell This refers to the number of electrolysis chambers.

[0046] According to electrochemical theory, the voltage U of a single electrolysis chamber is... cell Including the minimum voltage U required to start electrolysis rev Ohmic overvoltage U ohm and activation overvoltage U act .

[0047]

[0048] Among them: U rev The minimum voltage required to start electrolysis, U ohm For ohmic overvoltage, U act To activate the overvoltage, T el I is the temperature of the electrolytic cell. el For direct current, A el t1 represents the electrode area; r1 and r2 are the ohmic resistance parameters of the electrolyte; s, t1, t2, and t3 are the electrode overvoltage coefficients.

[0049] According to Faraday's law, the hydrogen production rate of an electrolyzer... It has a linear relationship with the electrolysis current and is also proportional to the number of electrolysis chambers, as calculated below:

[0050]

[0051] Where: η F denoted by F, where z is the Faraday efficiency; z is the number of electrons transferred in the reaction; and F is the Faraday constant.

[0052] Faraday efficiency η F It changes with the current, and the empirical expression is calculated as follows:

[0053]

[0054] Where f1 and f2 are the coefficients of Faraday efficiency.

[0055] Assuming negligible hydrogen leakage in the electrolyzer, the hydrogen accumulation rate at the cathode is... Hydrogen accumulation at the end of hydrogen production The calculation is as follows:

[0056]

[0057]

[0058] in: The hydrogen production rate of the electrolyzer; t0 represents the hydrogen discharge rate from the electrolyzer; t0 and t1 represent the initial and final times of hydrogen production, respectively. This represents the amount of hydrogen accumulated at the initial moment of hydrogen production.

[0059] In addition, the hydrogen pressure p in the electrolyzer el It can be obtained from the ideal gas law, and the calculation is as follows:

[0060]

[0061] Where: R is the molar gas constant; V el This represents the volume of the cathode.

[0062] Electrolytic cell energy efficiency η e The calculation formula is:

[0063]

[0064] In the formula: U tn It is a thermal neutral potential.

[0065] The established mass transport model for a single-unit electrolyzer is as follows:

[0066] According to the laws of conservation of charge and conservation of mass, the amount of hydrogen and oxygen produced per unit time... and and the mass of water decomposed per unit time Calculated by the following formula:

[0067]

[0068] in: and These represent the amounts of hydrogen and oxygen produced per unit time, respectively. A is the molar mass of water; cell j is the cross-sectional area of ​​the region through which the current flows in the electrolysis chamber; el This represents the operating current density.

[0069] To maintain the water balance in the electrolysis chamber, an equal amount of water needs to be added to the anode. The mass of water consumed per unit time due to electroosmosis is... for:

[0070]

[0071] Where D is the electroosmotic motion coefficient.

[0072] Because the evaporation process absorbs heat from the electrolyzer, affecting energy exchange within the cell, the influence of water vapor cannot be ignored in energy calculations. (The saturated vapor pressure of hydrogen...) for:

[0073]

[0074] Wherein: T el The temperature of the electrolyzer is a4-a0, and the saturated vapor pressure coefficient of hydrogen is a4-a0.

[0075] The amount of water vapor leaving the electrolyzer in the form of hydrogen per unit time for:

[0076]

[0077] Where: p K This is the cathode pressure. Similarly, at the anode, the saturated vapor pressure of oxygen is... The amount of water vapor leaving the electrolyzer with oxygen per unit time for:

[0078]

[0079]

[0080] In the formula, b4-b0 is the saturated vapor pressure coefficient of oxygen, and p A This is the gas pressure at the anode.

[0081] The energy conversion model for a single electrolytic cell is established as follows:

[0082] First, the input power P of the electrolytic cell el The input current, derived from the power grid, is expressed as the product of the input current and the operating voltage of the electrolytic cell:

[0083] P el =j el A cell U cell N cell

[0084] Where: j el For the operating current density, A cell U is the cross-sectional area of ​​the region through which the current flows in the electrolysis chamber; cell For the voltage of a single electrolysis cell, N cell This refers to the number of electrolysis chambers;

[0085] Most of the input power to the electrolyzer is consumed in the water electrolysis reaction, storing the energy as hydrogen gas. The energy used to generate hydrogen gas is... Consumption is:

[0086]

[0087] Where ΔH is the calorific value of hydrogen.

[0088] When the water injected into the electrolyzer participates in the electrolysis reaction, it needs to be heated to the operating temperature T of the electrolyzer. el The power consumed in this process for:

[0089]

[0090] Among them, T sur At room temperature This is the specific heat capacity of water.

[0091] The amount of water vapor generated from hydrogen and oxygen, and the endothermic power P of vaporization into water vapor. Vapor for:

[0092]

[0093] Where, ΔH Vap This refers to the amount of heat absorbed by the evaporation of one kilogram of water at the rated operating temperature of the electrolytic cell.

[0094] Due to the temperature difference between the electrolytic cell and the environment, a portion of the power is dissipated as external heat dissipation power P. Surface Consumption, expressed as:

[0095] P Surface =(T el -T Sur )α AC A AC

[0096] Where, α AC A is the heat exchange coefficient. AC This represents the heat exchange area. The product of these two values ​​was determined through engineering experiments to be 152.63 W / K.

[0097] If no additional power is injected or absorbed from the outside through the temperature control system, the remaining power P of the electrolytic cell will be... sum for:

[0098]

[0099] The rate of change of temperature in the electrolytic cell during operation for:

[0100]

[0101] Among them, C ele It is the heat capacity of the electrolytic cell, P Control The power injected into or absorbed by the temperature control system into the electrolytic cell is related to the structure of the electrolytic cell.

[0102] Furthermore, the model building module includes the following system models: a heat exchanger model, an alkali circulation system model, a compressor model, and a hydrogen storage tank model. Detailed diagrams of the electrolyzer auxiliary system model are available in [link to diagram]. Figure 2 .

[0103] The heat exchanger model of the electrolytic cell auxiliary system is established as follows:

[0104] The energy balance equations for the hot and cold sides of the heat exchanger are as follows:

[0105]

[0106]

[0107] Where: subscripts h and c represent heat flux and cold flux, respectively; ρ lye and ρ cw The densities of the alkaline solution and cooling water are respectively; V h and V c These are the hot and cold side volumes of the heat exchanger, respectively; C p，lye and C p,cw These are the heat capacities of the alkaline solution and the cooling water, respectively. The temperature of the imported alkali solution. The temperature of the liquid in the buffer tank. The temperature of the inlet cooling water. q represents the outlet cooling water temperature. lye and q cw These represent the mass flow rates of the alkali solution and cooling water, respectively; U is the heat transfer coefficient, and A... HX Where ΔT is the heat exchange area; LMTD The logarithmic mean temperature difference for countercurrent flow is calculated as follows:

[0108]

[0109] The established model of the alkaline solution circulation system of the electrolytic cell auxiliary system is as follows:

[0110] The temperature of the alkaline solution after mixing the electrolyte streams from all electrolyzers is calculated from the table below:

[0111]

[0112] in: For water consumption during electrolysis, T k and q lye,k Let C be the temperature and inlet alkali flow rate of the k-th electrolytic cell. p,w and C p,lye The heat capacities of the alkaline solutions are those of water and alkaline solution, respectively. T ref The reference temperature for enthalpy calculation is taken as 25℃;

[0113] The mass balance calculation for the buffer tank is as follows:

[0114]

[0115] Where: ρ lyeLet V be the density of the alkali solution flow, V be the volume of the buffer tank, and A be the density of the alkali solution flow. bt h is the cross-sectional area of ​​the buffer tank. bt q represents the height of the liquid in the buffer tank. out q H2O and q lye These are the mass flow rates of each stream;

[0116] The energy balance equation for the buffer tank is:

[0117]

[0118] The left side of the above equation can be rewritten as:

[0119]

[0120] After simplifying the equation, we get:

[0121]

[0122] The compressor model of the electrolytic cell auxiliary system is established as follows:

[0123]

[0124] in: α is the hydrogen molar flow rate at the compressor output; W is the compression work of the compressor; α comp For compressor efficiency, P comp T represents the compressor power. el and p el p represents the compressor inlet gas temperature and pressure. sto The compressor outlet gas pressure is equal to the hydrogen pressure in the gas storage tank, K is the multistage efficiency, and R is the gas constant.

[0125] Assumption Equal to the total flow rate of hydrogen from all electrolyzers Solve for P comp The above equation yields:

[0126]

[0127] A centrifugal compressor is a type of rotary compressor with a fixed pressure ratio, therefore P comp As the dependent variable, K is calculated using the above formula. K is related to the adiabatic component g, and is calculated as follows:

[0128]

[0129] The multi-directional efficiency E of centrifugal compressors p It is between 0.7 and 0.75. For the calculations in this invention, it is assumed that E p =0.75. The adiabatic index γ of diatomic hydrogen is 1.4.

[0130] Similarly, since O2 is also a diatomic molecule, the γ and x values ​​of oxygen are the same as those of hydrogen. Furthermore, to simplify the model, a formula is used to calculate the power requirement of the oxygen compressor. (Calculated by chemometrics).

[0131] The hydrogen storage tank model of the electrolyzer auxiliary system is established as follows:

[0132]

[0133] in, The molar content of hydrogen in the storage tank. Let n be the molar flow rate of hydrogen at the outlet. Substituting the ideal gas equation n = pV / RT into the equation:

[0134]

[0135] Among them, V sto For storage volume, T sto Storage temperature (°C), R is the gas constant. Operating pressure storage. It is a dynamic variable.

[0136] The outlet molar flow rate is calculated using the valve equation as follows:

[0137]

[0138] Where, k vlv Where z is the valve constant, and p is the valve displacement. out External pressure; storage temperature T sto Ideally, the temperature is controlled at 25°C, assuming a constant pressure in the electrolytic cell. The pressure inside the container increases with the increase of gas, and the inlet flow pressure must be higher than the storage pressure in order to allow it to enter the storage.

[0139] Furthermore, the grid-connected installation module includes:

[0140] Based on a DC transformer (LLC-DAB converter) with a symmetrical resonant dual active bridge structure as its submodule, fundamental wave analysis is used for modeling; the influence of line impedance within the topology is ignored, and the equivalent circuit of the power conversion system converter is simplified. According to... Figure 3a The topology of the neutron module is modeled using fundamental wave analysis, U AB and U CD This represents a positive and negative square wave voltage with a duty cycle of 0.5. Due to the symmetry of the DAB converter topology, an external phase shift control angle exists between the high and low voltage full-bridge converters. Ignoring the influence of line impedance within the topology, the equivalent circuit of the power conversion system converter is shown below. Figure 3b Among them, B iFor the i-th switch in a parallel Buck circuit, D i U is the i-th unidirectional diode in a parallel Buck circuit; B U is the output voltage of the Buck circuit. L This refers to the port voltage of the LLC-DAB converter.

[0141] According to Kirchhoff's laws, the above equivalent circuit derivation yields:

[0142]

[0143]

[0144]

[0145] Where: C r1 L r1 These are the capacitor and inductor of the high-voltage side full-bridge resonant branch, C. r2 L r2 These are the capacitance and inductance of the low-voltage side full-bridge resonant branch, respectively; n is the transformer turns ratio. i1 and i2 are the high-voltage side and low-voltage side currents, respectively, and e1 and e2 are the high-voltage side and low-voltage side induced electromotive forces, respectively. m1 For L m The current.

[0146] For U AB and U CD Perform Fourier transform analysis using the fundamental component U AB1 and U CD1 Replace U AB and U CD To simplify analysis and calculation, its accuracy meets the requirements. AB1 and U CD1 The expression is:

[0147]

[0148]

[0149] Where, ω s The primary side angle frequency of the high and low voltage full bridge is... For the external phase shift control angle, U H and U L These are the port voltages on both sides of the converter;

[0150] The active power transmitted by the submodule is:

[0151]

[0152] The DC voltage gain is:

[0153]

[0154] in: Quality Factor f s R is the primary side angular frequency of the high and low voltage full bridge. eq C represents the equivalent load value coupled to the primary side of the transformer. r1 L r1 These are the capacitor and inductor of the high-voltage side full-bridge resonant branch, ω r1 f r1 These are the angular frequency and frequency of the high-voltage side full-bridge resonant branch, respectively. r2 L r2 These are the capacitor and inductor of the low-voltage side full-bridge resonant branch, respectively; L m is the magnetizing inductance of the high-frequency isolation transformer, and n is the transformer turns ratio.

[0155] The alkaline electrolyzer in the electro-hydrogen-chemical coupling system receives power commands P from the power grid dispatch center under multiple constraints. gref Hydrogen is produced and then compressed and stored to supply hydrogen to downstream coal chemical processes. The system control diagram is as follows: Figures 4a-4d As shown, this includes temperature control, hydrogen pressure and flow control, hydrogen storage capacity constraint in the hydrogen storage tank, and power control under multiple constraints. In the diagram: V H2-out-ref This is a reference value for the hydrogen emission rate; P comp-ref This is a reference value for the compressor's compression power; p el-ref This is a reference value for the hydrogen pressure in the electrolyzer; T el-ref This is the temperature reference value for the electrolytic cell; P sref The power command value considering the hydrogen storage capacity constraint within the hydrogen storage tank; P ref This represents the actual reference power of the electrolyzer. Since temperature and force both affect the hydrogen production, energy consumption, safety, and lifespan of the electrolyzer, the variable load operation of the water electrolysis hydrogen production system must meet its own constraints as well as the constraints of downstream coal chemical hydrogen use. The following mainly introduces the control strategy for the electro-hydrogen-chemical coupling system considering multiple constraints.

[0156] Considering the temperature constraints of the electrolytic cell as follows:

[0157] As can be seen from the thermodynamic model, changes in the electrolyzer power will affect the heat Q generated inside the electrolyzer. gen The higher the power, the more heat the electrolyzer generates, which in turn affects the temperature of the electrolyzer. Since temperature affects the hydrogen production, safety, and lifespan of the electrolyzer, there is a certain temperature threshold for its normal operation. Therefore, to prevent the electrolyzer from overheating, a cooling system is needed to cool the alkali solution, thereby cooling the electrolyzer. Specifically, when the electrolyzer is operating, if its temperature T... el Exceeding threshold Tth The cooling water flow rate is adjusted via a PI controller to maintain the electrolytic cell temperature at a constant value, thus suppressing temperature fluctuations under varying load conditions. See the temperature control block diagram below. Figure 4a .

[0158] Considering the pressure constraints of the electrolytic cell as follows:

[0159] To ensure the safe and efficient operation of the electrolyzer, the hydrogen pressure in the electrolyzer should be maintained at a constant value p. el-ref See the pressure control block diagram. Figure 4b The hydrogen pressure in the electrolyzer is kept constant by controlling the required hydrogen discharge rate, and the hydrogen is discharged at a reference rate using a compressor. The output is sent to the hydrogen storage tank. Specifically, a PI controller is used to control the hydrogen pressure p in the actual electrolyzer. el By controlling the process, a reference value for the hydrogen discharge rate from the electrolyzer is obtained. Simultaneously, through flow control, according to The pressure p of the hydrogen storage tank sto Hydrogen pressure p in the electrolyzer el The compressor's compression power reference value P is calculated. comp-ref and P comp-ref This is input into the compressor model to ensure a constant hydrogen pressure in the electrolyzer.

[0160] Power control considering the hydrogen storage capacity constraint in the hydrogen storage tank is as follows:

[0161] The hydrogen storage tank serves as a buffer between the electrolyzer and downstream hydrogen consumption stages. Its hydrogen storage capacity is related to the hydrogen input rate and the hydrogen consumption rate in the downstream coal chemical process. The hydrogen output rate to the storage tank is also relevant. Hydrogen production rate of the electrolyzer Hydrogen pressure p in the electrolyzer el The hydrogen production rate of an electrolyzer is determined by its power output, which is related to the electrolysis current. Higher electrolyzer power results in a higher current and thus a higher hydrogen production rate. Therefore, there are mutual influences between the electrolyzer, hydrogen storage tank, and downstream coal chemical processes. It is necessary to ensure the safe and stable operation of the hydrogen storage tank and downstream coal chemical processes while simultaneously enabling the electrolyzer to respond quickly to power grid commands.

[0162] At any given moment, the amount of hydrogen stored in the hydrogen storage tank is n. sto (t) should satisfy the following constraints:

[0163]

[0164] in: The minimum amount of hydrogen storage required to provide a stable hydrogen supply for downstream coal chemical industry; This is the maximum capacity of the hydrogen storage tank.

[0165] The amount of hydrogen stored in the hydrogen storage tank constrains the electrolysis current, thereby limiting the power of the electrolyzer. When the hydrogen storage tank reaches its upper limit... When the alkaline electrolyzer is forced to shut down, the reference power P of the electrolyzer, considering the hydrogen storage capacity constraint, is... sref =0 (i.e., P) ref =P sref =0), then the amount of hydrogen stored in the hydrogen storage tank gradually decreases until the hydrogen storage tank leaves sufficient storage space n, after which the electrolyzer will follow the power command value of the power grid again, P ref =P sref =P gref When the hydrogen storage tank reaches its lower limit... At this time, the electrolyzer operates at maximum power, achieving the highest hydrogen production rate and ensuring a stable hydrogen supply for downstream coal chemical processes. The reference power for the electrolyzer at this time is P. max (i.e. P) ref =P sref =P max Then, the amount of hydrogen stored in the hydrogen storage tank gradually increases. Similarly, when the hydrogen storage tank has stored Δn of hydrogen, the electrolyzer follows the power command value, P. ref =P sref =P gref When the hydrogen storage capacity in the hydrogen storage tank does not exceed its upper or lower limit constraint value, the electrolyzer follows the power command value P from the power grid. ref =P sref =P gref Normal operation. See detailed power control block diagram. Figure 4c , Figure 4d .

[0166] Furthermore, based on the aforementioned modeling method and control strategy, the topological relationship matrices A, B, and C between the electrolytic cell array, auxiliary system array, and power conversion system array are used to quickly coordinate the linear expansion of the coupling relationship between the unit array and the power distribution system. For example, after calculating the energy consumption of the electrolytic cell using the above modeling formula, considering the energy consumption of the auxiliary system array matched with the electrolytic cell and the input power of the power conversion system, the topological relationship matrix can be used for convenient solution.

[0167]

[0168]

[0169] P BoP =AP Stack

[0170] P PCS =BP Stack

[0171] Where: P stack,iP represents the input power of the i-th individual electrolytic cell in the electrolytic cell array. BoP,i P represents the input power of the i-th single auxiliary system in the auxiliary system array. PCS,i The input power is the i-th power conversion system in the power conversion system array.

[0172] By utilizing the topological relationship matrices A, B, and C between the electrolytic cell array, auxiliary system array, and power conversion system array, the energy consumption of the electrolytic cell under the auxiliary system array and power conversion system array matched with the electrolytic cell can be quickly calculated.

[0173] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of this application can be implemented in various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0174] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0175] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0176] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0177] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0178] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for electromechanical transient modeling of a large-capacity electrolytic cell considering a topological relation matrix, characterized in that, include: Based on the power grid and load configuration structure, a topological relationship matrix is ​​established between the electrolytic cell array, auxiliary equipment system, and power conversion system, including: First, the electrolytic cell, auxiliary system and power conversion system in a given scenario are numbered; then, according to the topological correspondence between the electrolytic cell sequence, auxiliary system sequence and power conversion system in a given scenario, topological relationship matrices A, B and C are established between each pair of the electrolytic cell sequence, auxiliary system sequence and power conversion system sequence. Considering power, hydrogen balance and various equipment constraints, a model is created for the large-capacity water electrolyzer unit and auxiliary system to obtain an integrated electrolyzer system operation model. Based on the overload characteristics and initial capacity of the integrated electrolytic cell system, the power conversion system is modeled and grid-connected, resulting in a grid-connected system model. Based on the equipment operating threshold and combined with the bus voltage and the dynamic characteristics of the electrolytic cell, a control strategy for the electrolytic cell system under multiple constraints is proposed.

2. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix as described in claim 1, characterized in that, The modeling of the large-capacity water electrolyzer unit and auxiliary system, taking into account power, hydrogen balance, and various equipment constraints, yields an integrated electrolyzer system operation model, including: First, the large-capacity electrolyzer unit is modeled, including the following system models: electrochemical model, mass transport model, and energy conversion model. Based on electrochemical theory, the voltage model for a single electrolysis chamber is established as follows: ； Among them: U rev The minimum voltage required to start electrolysis, U ohm For ohmic overvoltage, U act To activate the overvoltage, T el I is the temperature of the electrolytic cell. el For direct current, A el t1 represents the electrode area; r1 and r2 are the ohmic resistance parameters of the electrolyte; s, t1, t2, and t3 are the electrode overvoltage coefficients. Assuming negligible hydrogen leakage in the electrolyzer, the hydrogen accumulation rate at the cathode is... Hydrogen accumulation at the end of hydrogen production The calculation is as follows: ； in: The hydrogen production rate of the electrolyzer; This refers to the number of electrolysis chambers; denoted by F, where z is the Faraday efficiency; z is the number of electrons transferred in the reaction; and F is the Faraday constant. t0 represents the hydrogen discharge rate from the electrolyzer; t0 and t1 represent the initial and final times of hydrogen production, respectively. This represents the amount of hydrogen accumulated at the initial moment of hydrogen production.

3. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix according to claim 2, characterized in that, Modeling methods for large-capacity water electrolysis cell units include: The mass transport model for a single-unit electrolyzer is established as follows: According to the laws of conservation of charge and conservation of mass, the amount of hydrogen and oxygen produced per unit time... and and the mass of water decomposed per unit time Calculated by the following formula: ； in: and These represent the amounts of hydrogen and oxygen produced per unit time, respectively. The molar mass of water; This is the cross-sectional area of ​​the region through which the current flows in the electrolysis chamber; The operating current density; saturated vapor pressure of hydrogen Calculated by the following formula: ； Wherein: T el The temperature of the electrolyzer is a4-a0, and the saturated vapor pressure coefficient of hydrogen is a4-a0.

4. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix according to claim 3, characterized in that, Modeling a large-capacity water electrolysis cell unit includes: The energy conversion model for a single-unit electrolytic cell is established as follows: First, the input power P of the electrolytic cell el The input current, derived from the power grid, is expressed as the product of the input current and the operating voltage of the electrolytic cell: ； in: Energy consumption for generating hydrogen; ΔH is the calorific value of hydrogen; To ensure that the water injected into the electrolyzer rises to the electrolyzer's operating temperature T during the electrolysis reaction. el The power consumed in the process; The mass of water consumed per unit time due to electroosmosis. P is the specific heat capacity of water. Surface To account for the heat dissipation power due to the temperature difference between the electrolytic cell and the environment, T sur At room temperature, α AC A is the heat exchange coefficient. AC For heat exchange area; Considering that no additional power is injected or absorbed from the outside through the temperature control system, the remaining power P of the electrolytic cell is... sum The calculation is as follows: ； Among them, P Vapor The amount of water vapor generated in the hydrogen and oxygen production is the endothermic power of vaporization into water vapor.

5. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix according to claim 4, characterized in that, Modeling a large-capacity water electrolysis cell unit includes: The circuit model of the single-unit electrolytic cell is established as follows: The electrolyzer model is based on the inverse voltage U of the electrolyzer stack. rev Internal resistance R i It consists of an electric double layer branch (EDL) and a transmission resistance R. m and overpotential capacitance C op The composition was obtained by fitting the polarization curves of the measurement experiment; ； Among them: U t and i t These are the voltage and current across the electrolytic cell model; E rev0 and R i0 Let T0 be the initial values ​​of the reverse voltage and internal resistance at temperature T0 and pressure p0, k be the parameters of the fitted curve, C be the temperature coefficient of resistance, and F be the Faraday constant.

6. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix according to claim 1, characterized in that, Modeling the auxiliary equipment system of the electrolytic cell includes: A model of the electrolyzer auxiliary system was established, including the following system models: heat exchanger model, alkali circulation system model, compressor model, and hydrogen storage tank model. The energy balance equations for the hot and cold sides of the heat exchanger in the auxiliary system of the electrolytic cell are as follows: ； Where: subscripts h and c represent heat flux and cold flux, respectively; ρ lye and ρ cw The densities of the alkaline solution and cooling water are respectively; V h and V c These are the hot and cold side volumes of the heat exchanger, respectively; C p,lye and C p,cw These are the heat capacities of the alkaline solution and the cooling water, respectively. The temperature of the imported alkali solution. The temperature of the liquid in the buffer tank. The temperature of the inlet cooling water. q represents the outlet cooling water temperature. lye and q cw These represent the mass flow rates of the alkali solution and cooling water, respectively; U is the heat transfer coefficient, and A... HX Where ΔT is the heat exchange area; LMTD The logarithmic mean temperature difference for countercurrent flow.

7. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix according to claim 6, characterized in that, The establishment of the electrolytic cell auxiliary system model includes: The established model of the alkaline solution circulation system of the electrolytic cell auxiliary system is as follows: The temperature of the alkaline solution after mixing the electrolyte streams from all electrolyzers is calculated as follows: ； Wherein: T k and q lye,k Let C be the temperature and inlet alkali flow rate of the kth electrolytic cell; p,w and C p,lye The heat capacities of the alkaline solution and the alkaline solution are respectively those of water and alkaline solution; Water consumption for electrolysis; T ref The reference temperature for enthalpy calculation is taken as 25℃; The mass balance calculation for the buffer tank is as follows: ； in: Let V be the density of the alkali solution flow, V be the volume of the buffer tank, and A be the density of the alkali solution flow. bt h is the cross-sectional area of ​​the buffer tank. bt q represents the height of the liquid in the buffer tank. out , and q lye These are the mass flow rates of each stream; The total energy consumption of the heat exchanger and alkali circulation system is calculated as follows: 。 8. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix according to claim 6, characterized in that, The establishment of the electrolytic cell auxiliary system model includes: The compressor model of the electrolytic cell auxiliary system is specifically as follows: ； in: α is the hydrogen molar flow rate at the compressor output; W is the compression work of the compressor; α comp For compressor efficiency, P comp T represents the compressor power. el and p el p represents the compressor inlet gas temperature and pressure. sto The compressor outlet gas pressure is equal to the hydrogen pressure in the gas storage tank, K is the multistage efficiency, and R is the gas constant. Assumption Equal to the total flow rate of hydrogen from all electrolyzers Solve for P from the above equation comp get: 。 9. A method for electromechanical transient modeling of a large-capacity electrolytic cell considering a topological relation matrix, as described in claim 8, is characterized in that... The establishment of the electrolytic cell auxiliary system model includes: The hydrogen storage tank model of the electrolyzer auxiliary system is established as follows: The total molar balance of the gas storage tank is calculated as follows: ； in: The molar content of hydrogen in the storage tank. Let n be the molar flow rate of hydrogen at the outlet; substituting the ideal gas n = pV / RT into the equation: ； Where: V sto For storage volume, T sto The storage temperature is R, the gas constant is R, and the operating pressure of the storage tank is R. It is a dynamic variable; The outlet molar flow rate is given by the valve equation as follows: ； Where, k vlv Where z is the valve constant, p is the valve displacement, and z is the valve displacement. out External pressure; assuming storage temperature T sto Ideally, the temperature is controlled at 25 °C, and the pressure in the electrolytic cell remains constant.

10. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix according to claim 1, characterized in that, Based on the overload characteristics and initial capacity of the integrated electrolytic cell system, the power conversion system is modeled and grid-connected, resulting in a grid-connected system model including: Based on a DC transformer with a symmetrical resonant dual active bridge submodule, fundamental wave analysis is used for modeling. The influence of line impedance within the topology is ignored, and the equivalent circuit of the power conversion system converter is simplified. The voltage U at both ends of the DC transformer is then analyzed. AB and U CD Perform Fourier transform analysis using the fundamental component U AB1 and U CD1 Replace U AB and U CD To simplify the analysis and calculation, the following is an example: ； ； in, The primary side angle frequency of the high and low voltage full bridge is... For the external phase shift control angle, U H and U L These are the port voltages on both sides of the converter before simplification; The active power transmitted by the DC transformer is: ； The DC voltage gain is: ； in: , , , Quality factor , R is the primary side angular frequency of the high and low voltage full bridge. eq C represents the equivalent load value coupled to the primary side of the transformer. r1 L r1 These are the capacitor and inductor of the high-voltage side full-bridge resonant branch, respectively. f r1 These are the angular frequency and frequency of the high-voltage side full-bridge resonant branch, respectively. r2 L r2 These are the capacitor and inductor of the low-voltage side full-bridge resonant branch, respectively; L m is the magnetizing inductance of the high-frequency isolation transformer, and n is the transformer turns ratio.

11. The electromechanical transient modeling method for a large-capacity electrolytic cell considering a topological relation matrix according to claim 1, characterized in that, Based on the equipment operating threshold and combined with the bus voltage and the dynamic characteristics of the electrolyzer, a control strategy for the electrolyzer system under multiple constraints is proposed, including: temperature control of the electrolyzer by adjusting the cooling water flow rate through the controller; pressure control of the electrolyzer calculated based on the discharge rate reference value, the pressure of the hydrogen storage tank, and the hydrogen pressure in the electrolyzer; and constraint of the electrolysis current based on the amount of hydrogen stored in the hydrogen storage tank, thereby constraining the power of the electrolyzer.

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