Electricity-hydrogen energy hub collaborative optimization control method, system, equipment and medium

Abstract

The invention provides an electricity-hydrogen energy hub collaborative optimization control method, system, equipment and medium, and belongs to the field of electricity-hydrogen fusion hub collaborative operation control, the method comprises the following steps: constructing an electricity-hydrogen energy hub structure which couples a photovoltaic power generation unit, a hydrogen energy unit and a storage battery unit to a direct current bus, and establishing each unit model; determining the output of each unit through each unit model, and designing a cooperative control strategy of the electricity-hydrogen fusion hub based on a cooperative control theory; constructing a small signal model based on each unit model, and determining a specific value of a duty ratio in the small signal model in combination with a cooperative control strategy and the output of each unit; and verifying the stability of the proposed cooperative control strategy under the condition of small disturbance of the DC micro-grid through a small signal model, and determining the optimal value of each control parameter of the cooperative control strategy. Cooperative operation of all units in the electro-hydrogen fusion hub can be effectively achieved, the stability of bus voltage is ensured, and the overall operation performance of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of coordinated operation control of an electric-hydrogen fusion hub, and in particular to a coordinated optimization control method, system, equipment and medium for an electric-hydrogen energy hub. Background Art

[0002] Hydrogen energy has both material and energy properties. Its energy properties can support long-term electricity demand and ensure real-time power balance of the power system. Its material properties can provide long-term energy storage needs and support longer-term energy supply capabilities. Therefore, hydrogen energy effectively makes up for the limitations of electricity as a secondary energy source. At the same time, the efficient conversion and transmission capabilities of electricity can break through the bottleneck of the comprehensive utilization of hydrogen energy in multiple scenarios, especially in terms of energy storage and flexible scheduling.

[0003] Based on this, building an energy hub that is "mainly electricity-based and integrates electricity and hydrogen" has become an important means to support the flexible adjustment of the new power system. The electricity-hydrogen integration energy hub is a complex system that includes multiple key components such as electrolysis hydrogen production, hydrogen storage, charging, hydrogen injection, and fuel cells, involving multiple energy flow links between electricity and hydrogen energy. There are many types of equipment in the system, and the energy and material conversion and transmission relationships between the components are complex, with a high degree of coupling effect.

[0004] In order to achieve efficient operation of the electric-hydrogen fusion energy hub, it is necessary to deeply understand the energy-matter coupling relationship between each device and apply appropriate coordinated control strategies. Through these strategies, the potential of each device can be fully utilized, the overall efficiency of the system can be improved, and its safe and stable operation can be ensured. However, existing coordinated control technologies are mostly based on linear system models and often fail under large disturbance conditions. In addition, since the electric-hydrogen fusion energy hub is highly coupled and is a nonlinear system with a higher dimension, higher requirements are placed on the stability and robustness of the control strategy. Therefore, there is an urgent need to develop better coordinated control strategies. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a method, system, equipment and medium for collaborative optimization control of an electric hydrogen energy hub. Against the background of the continuous improvement of the penetration rate of new energy and the deep integration of the power system and hydrogen energy, the present invention conducts an in-depth analysis of the structure and working principle of the electric hydrogen hub system, and constructs the overall structure and mathematical model of the system. Subsequently, the collaborative control theory is applied to the system, and according to the specific structure and operating characteristics of the electric hydrogen hub, a comprehensive control scheme based on collaborative control is proposed to achieve efficient and stable operation of the electric hydrogen energy hub.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, an embodiment of the present invention provides a method for coordinated optimization control of an electric-hydrogen energy hub, comprising the following steps:

[0008] Construct an electric hydrogen energy hub structure that couples photovoltaic power generation units, hydrogen energy units, and battery units to the DC bus, and establish models for each unit;

[0009] Determine the output of each unit through each unit model, and design the coordinated control strategy of the electric-hydrogen fusion hub based on the coordinated control theory;

[0010] A small signal model is constructed based on each unit model. The stability of the proposed cooperative control strategy under small disturbances in the DC microgrid is verified through the small signal model, and the optimal values ​​of each control parameter of the cooperative control strategy are determined.

[0011] Furthermore, the construction of the electric hydrogen energy hub structure that couples the photovoltaic power generation unit, the hydrogen energy unit, and the battery unit to the DC bus, and establishing the model of each unit includes:

[0012] The structure of the electric-hydrogen energy hub is constructed according to the composition of the electric-hydrogen energy hub and the connection between the equipment, in which the photovoltaic power generation unit, fuel cell, electrolyzer and battery are connected to the DC bus through the converter;

[0013] The voltage dynamic equation of the DC bus capacitor is as follows:

[0014] (1)

[0015] Among them, C dc 、u dc are the DC bus capacitance and voltage respectively, in V; P pv , P fc , P el , P bat , P load They are the power from photovoltaics flowing into the DC bus, the power from fuel cells flowing into the DC bus, the power from electrolyzers flowing into the DC bus, the power from batteries flowing into the DC bus, and the power from loads flowing into the DC bus, in W.

[0016] According to the type and technical characteristics of each unit, the mathematical model of photovoltaic power generation unit, fuel cell, electrolyzer, battery and their connection circuit is established;

[0017] For a photovoltaic power generation unit, which is composed of multiple photovoltaic cells connected in series and parallel to form photovoltaic power sources of different capacities, the output current of the photovoltaic cell is:

[0018] (2)

[0019] in:

[0020] (3)

[0021] (4)

[0022] Among them, I p ,I ph ,I p0 ,I sh ,I d They are the photovoltaic cell output current, photocurrent, diode reverse saturation current, leakage current and the current flowing through the diode, in A; q is the electron charge, taken as ; U p is the open circuit voltage of the photovoltaic cell, in V; R ss , R sh are the equivalent series resistance and parallel resistance, in Ω; A is the ideal quality factor of the diode; k is the Boltzmann constant, which is ; T pv is the photovoltaic cell temperature, in K; exp() is the exponential function;

[0023] The photovoltaic power generation unit is connected through a Boost circuit and uses maximum power point tracking control;

[0024] The fuel cell uses a PEM fuel cell, and the internal voltage equation corresponding to the PEM fuel cell is:

[0025] (5)

[0026] Among them, E fc is the voltage inside the fuel cell; E0 is the standard reference potential under standard conditions, in V; R is the gas constant, with a value of 8.3143 J / ( ), T fc is the fuel cell temperature, in K; F is the Faraday constant, with a value of 96485C / mol; is the hydrogen partial pressure, in Pa; is the oxygen partial pressure, in pa; E d,fc Delayed effect voltage for fuel and oxidizer;

[0027] The fuel cell output voltage is:

[0028] (6)

[0029] in:

[0030] (7)

[0031] (8)

[0032] (9)

[0033] Among them, U fc,act , U fc,ohm , U fc,conc and U fcc is the polarization voltage, ohmic voltage, concentration voltage, and output voltage of the fuel cell, in V; i fcd is the unit current density of the fuel cell, in A / cm 2 ; a, b are the constants of the Tafel equation, in V / K; R fc,ohm is the resistance of the polymer film, the resistance between the film and the electrode, and the integrated resistance between the electrodes, in Ω; z is the number of participating electrons; i fc,limit is the limiting current density of the fuel cell, in A / cm 2 ; T fc is the fuel cell temperature, in K;

[0034] Multiple fuel cells are connected in series and parallel to form a fuel cell stack, and its output power P fc for:

[0035] (10)

[0036] in:

[0037] (11)

[0038] (12)

[0039] Among them, u fc is the fuel cell stack voltage, in V; i fc is the fuel cell stack current, in A; N fcs 、N fcp are the number of fuel cells in series and parallel respectively; I fc is the fuel cell current, in A;

[0040] The fuel cell provides power to the DC bus through the Boost circuit, and the differential equation is established:

[0041] (13)

[0042] in:

[0043] (14)

[0044] Among them, i fcL is the inductor current in the boost circuit connected to the fuel cell, in A; C fc1 The low-voltage side capacitance of the boost circuit connected to the fuel cell, in F; L fcis the inductance of the boost circuit connected to the fuel cell, in H; D fc is the duty cycle of the boost circuit controller connected to the fuel cell;

[0045] A PEM electrolyzer is used, which consists of multiple electrolytic chambers connected in series, and multiple groups of electrolytic cells are connected in parallel to a DC power supply;

[0046] The voltage-current equation of the electrolysis chamber terminal voltage at any temperature is:

[0047] (15)

[0048] in:

[0049] (16)

[0050] (17)

[0051] (18)

[0052] Among them, E el , U el,act , U el,ohm and U el They are the open circuit voltage, polarization overvoltage, ohmic polarization voltage and terminal voltage of the electrolytic cell, in V; α H2O is the water activity between the anode and the electrolyte, here it is 1; T el is the electrolyte temperature, in K; α is the transfer coefficient; i eld is the electrolytic cell current density; i el,0 Electrolytic cell exchange current density; R el,ohm is the membrane resistance;

[0053] Multiple electrolytic chambers are connected in series and parallel to form an electrolytic cell stack, which consumes power P el for:

[0054] (19)

[0055] in:

[0056] (20)

[0057] (twenty one)

[0058] Among them, u el is the electrolysis voltage, in V; i el is the electrolysis current, in A; N els 、N elp are the number of electrolytic cells connected in series and in parallel respectively; I el is the electrolytic cell current, in A;

[0059] The DC bus provides electrical energy for the electrolyzer to produce hydrogen through the Buck circuit, and the differential equation is established as follows:

[0060] (twenty two)

[0061] Among them, i elL is the inductor current in the Buck circuit connected to the electrolytic cell, in A; C el2 The low-voltage side capacitance of the Buck circuit connected to the electrolytic cell, in F; L el is the inductance of the Buck circuit connected to the electrolytic cell, in H; D el is the duty cycle of the Buck circuit controller connected to the electrolyzer;

[0062] A lead-acid battery is selected as the electrochemical energy storage device, and its terminal voltage is:

[0063] (twenty three)

[0064] Among them, the controlled voltage source equation is:

[0065] (twenty four)

[0066] Among them, u bat 、E bat 、E bat0 and K bat They are the battery terminal voltage, internal potential, no-load voltage and polarization voltage, in V; Q n is the battery capacity, in Ah; I bat is the battery charge and discharge current, in A; B1 is the voltage change coefficient, in V; B2 is the capacity change coefficient, in ; R eq is the equivalent internal resistance of the battery, in Ω;

[0067] The battery state of charge S bat The expression for remaining capacity is:

[0068] (25)

[0069] Among them, S bat0 is the initial state of charge of the battery, in %;

[0070] The battery is charged and discharged via a bidirectional Buck-Boost circuit, and the differential equation is established:

[0071] (1) Buck working status:

[0072] (26)

[0073] (2) Boost working status:

[0074] (27)

[0075] Among them, i batL is the inductor current in the bidirectional Buck-Boost circuit connected to the battery, in A; C bat2 The low-voltage side capacitor of the bidirectional Buck-Boost circuit connected to the battery, in F; L bat is the inductance of the bidirectional Buck-Boost circuit connected to the battery, in H; D bat1 It is the duty cycle of the high-side switch controller of the bidirectional Buck-Boost circuit connected to the battery.

[0076] Furthermore, the output of each unit is determined through each unit model, and the coordinated control strategy of the electric-hydrogen fusion hub is designed based on the coordinated control theory, including:

[0077] Clarify the basic principles and framework of collaborative control theory, determine the coordination mechanism and information interaction mode between multi-unit models, and analyze the application of collaborative control theory in complex energy systems;

[0078] Consider the microgrid as an n-dimensional nonlinear system as shown in formula (28):

[0079] (28)

[0080] Where x is the system state vector; d is the control input; t is time; f is the function expression of x, d, and t;

[0081] Cooperative control is based on the derivation of control laws based on the nonlinear system model, including the definition of macro variables and the solution of control quantities. The macro variable Ψ(x) is a function of the state variable in the nonlinear system, and the state variable is selected according to the purpose to be achieved by the control system. Through cooperative control, the macro variable can converge and remain on the manifold Ψ(x)=0. The dynamic equation of the macro variable tending to the manifold after the system disturbance is described as:

[0082] (29)

[0083] Where N is a time constant, which determines the convergence speed of the macro variables to the manifold, and N>0;

[0084] Substituting the constructed macro variables into equation (28) into equation (29) yields:

[0085] (30)

[0086] By solving equation (29), we can obtain the solution of d. Under the action of d, the nonlinear system recovers stability from any state after being disturbed, and the macro variables move toward the manifold, gradually approaching the equilibrium point of the system.

[0087] Solving the ordinary differential equation (28) yields the macro variables:

[0088] (31)

[0089] Among them, Ψ(0) is the initial state of the macro variable;

[0090] According to the principles of collaborative control theory, the coordinated control strategy of the system is designed and constructed, including:

[0091] (1) Fuel cell control design:

[0092] The relationship between the input voltage and output voltage in the Boost circuit where the fuel cell is located is:

[0093] (32)

[0094] Combined with the differential equation of the Boost circuit, the macro control variables are designed as follows:

[0095] (33)

[0096] Among them, u fcref is the input voltage reference value of the Boost circuit, in V; k1 is the positive coefficient; i fcLref is the reference value of the inductor current of the Boost circuit, which is determined by the inductor current i fcL The value after low-pass filtering is determined in A;

[0097] Derivative (33) and substitute it into (29), we get the dynamic process of macro variable Ψ1 tending to the manifold:

[0098] (34)

[0099] Wherein, N1 is the time constant of the coordinated control of the fuel cell module;

[0100] According to equations (13) and (34), the duty cycle D of the boost circuit controller where the fuel cell is located is obtained: fc ’ The solution is:

[0101] (35)

[0102] When the system is in steady state operation, u fc =u fcref 、i fcL =i fcLref, from formula (35) we get D fc ’ is a constant, the fuel cell power is constant, and when the bus voltage fluctuates, D fc ’ The L based on the Boost circuit changes accordingly to achieve fuel cell power response. fc , C fc1 Parameters, N1 and k1 are determined according to the simulation operation, and the power of the fuel cell when the system is stable before and after the disturbance is obtained;

[0103] To achieve the change of fuel cell power in response to bus voltage changes, D fc ’ The value of satisfies the interval [0,1], which controls the on / off of the Boost circuit switch;

[0104] By modulating D fc ’ The corresponding fuel cell power is:

[0105] (36)

[0106] (2) Electrolyzer control design:

[0107] The relationship between the input voltage and output voltage in the Buck circuit where the electrolyzer is located is:

[0108] (37)

[0109] In order to ensure that the output power of the electrolyzer is equal to the set power, the macro variables are designed in combination with the Buck circuit differential equation as follows:

[0110] (38)

[0111] Among them, u elref is the reference value of the Buck circuit output voltage, in V; k2 is a positive coefficient; i elLref is the reference value of the inductor current of the Buck circuit, which is determined by the inductor current i elL The value after low-pass filtering is determined in A;

[0112] Derivative (38) and substitute it into (29), we get the dynamic process of macro variable Ψ2 tending to the manifold:

[0113] (39)

[0114] Wherein, N2 is the time constant of the coordinated control of the electrolyzer modules;

[0115] According to equations (22) and (39), the duty cycle D of the Buck circuit controller where the electrolyzer is located is obtained el The solution is:

[0116] (40)

[0117] When the system is in steady state operation, u el =u elref 、i elL =i elLref , we can get D from formula (40): el is a constant, the electrolytic cell power is constant, and when the bus voltage fluctuates, D el The L based on Buck circuit el , C el2 Parameters, N2, k2 are determined according to the simulation operation, and the power of the electrolyzer when the system is stable before and after the disturbance is obtained; in order to change the electrolyzer power in response to the bus voltage change, D el The value of satisfies the interval [0,1], which controls the opening and closing of the Buck circuit switch;

[0118] By modulating D el The corresponding electrolyzer power is:

[0119] (41)

[0120] (3) Battery control design:

[0121] ①Battery in Buck state:

[0122] Set the bus power as the difference between the power supply power and the load power, and use the mathematical model of each unit to calculate the formula Transform it and get:

[0123] (42)

[0124] In order to suppress the bus voltage change, the linear combination of battery power deviation and bus voltage deviation is selected to design the macro variable as:

[0125] (43)

[0126] Among them, u batref is the voltage reference value of the battery, in V; k3 and k4 are positive coefficients; i batLref is the reference value of the inductor current of the Buck-Boost circuit, which is determined by the inductor current i batL The value after low-pass filtering is determined in A; u dcref is the DC bus reference voltage, in V;

[0127] Deriving equation (43) and substituting it into equation (29), we obtain:

[0128] (44)

[0129] Among them, N3 is the time constant of cooperative control of the battery module in Buck state;

[0130] According to equations (26), (42) and (44), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained: bat1 The solution is:

[0131] (45)

[0132] ②Battery in Boost state:

[0133] In Boost mode, the battery is equivalent to a power source, and the expression for bus power balance becomes:

[0134] (46)

[0135] The macro variables of linear combination design are similar to the structure of Buck mode, as follows:

[0136] (47)

[0137] Among them, k5 and k6 are positive coefficients;

[0138] Deriving equation (47) and substituting it into equation (29), we obtain:

[0139] (48)

[0140] Wherein, N4 is the time constant of cooperative control of the battery module in the Boost state;

[0141] According to equations (27), (46) and (48), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained bat1 The solution is:

[0142] (49)

[0143] When the system is running in steady state, i bat =i batref 、u bat =u batref 、u dc =u dcref , fuel cell, and electrolyzer power change is 0, and the battery duty cycle is obtained from equations (45) and (49): , the power of the fuel cell, electrolyzer and battery will not change; from equation (47) and equation (49), we can get D based on the collaborative control theory design bat1 With D el , D fc ’and u dc There is a coupling relationship, the four influence each other, when u dc When fluctuation occurs, D bat1 , D el and D fc ’ Corresponding changes occur: when the DC bus voltage is higher than the rated value, the power surplus in the microgrid is reduced by increasing the electrolyzer power and the charging power of the battery; on the contrary, when the bus voltage is lower than the rated value, the system power is supplemented by increasing the fuel cell power and the discharging power of the battery.

[0144] Furthermore, the small signal model is constructed based on each unit model, the stability of the proposed collaborative control strategy under small disturbance of the DC microgrid is verified by the small signal model, and the optimal values ​​of each control parameter of the collaborative control strategy are determined, including:

[0145] In order to verify the stability of the proposed control strategy in the DC microgrid under small disturbances, a small signal model of the microgrid is established. First, the small signal models of the electrolyzer Buck circuit, the fuel cell Boost circuit, and the battery DC / DC loop are established respectively. Then, the photovoltaic and DC loads are regarded as constant power units, and the small signal model of the DC microgrid is obtained from the DC bus KCL relationship as shown in Equation (50):

[0146] (50)

[0147] Among them, the DC microgrid small signal model variables ,in A is a variable including voltage and current; DC is the coefficient matrix;

[0148] The DC microgrid small signal model constructed based on formula (50) is expressed by the coefficient matrix A DC Analyze the characteristic roots of the system; the collaborative control coefficient N is a time constant that determines the speed at which the macro variables converge to the manifold; in the system stability analysis, determine the value range of the control parameters.

[0149] In a second aspect, an embodiment of the present invention further provides an electric-hydrogen energy hub collaborative optimization control system, comprising the following modules:

[0150] The equipment power calculation module builds an electric hydrogen energy hub structure that couples the photovoltaic power generation unit, hydrogen energy unit, and battery unit to the DC bus, and establishes models for each unit;

[0151] Integrated control module, which determines the output of each unit through each unit model, and designs the coordinated control strategy of the electric-hydrogen fusion hub based on the coordinated control theory;

[0152] The control stability verification module builds a small signal model based on each unit model, verifies the stability of the proposed collaborative control strategy under small disturbances of the DC microgrid through the small signal model, and determines the optimal values ​​of each control parameter of the collaborative control strategy.

[0153] Furthermore, the device power calculation module implements:

[0154] The structure of the electric-hydrogen energy hub is constructed according to the composition of the electric-hydrogen energy hub and the connection between the equipment, in which the photovoltaic power generation unit, fuel cell, electrolyzer and battery are connected to the DC bus through the converter;

[0155] The voltage dynamic equation of the DC bus capacitor is as follows:

[0156] (1)

[0157] Among them, C dc 、u dc are the DC bus capacitance and voltage respectively, in V; P pv , P fc , P el , P bat , P load They are the power from photovoltaics flowing into the DC bus, the power from fuel cells flowing into the DC bus, the power from electrolyzers flowing into the DC bus, the power from batteries flowing into the DC bus, and the power from loads flowing into the DC bus, in W.

[0158] According to the type and technical characteristics of each unit, the mathematical model of photovoltaic power generation unit, fuel cell, electrolyzer, battery and their connection circuit is established;

[0159] For a photovoltaic power generation unit, which is composed of multiple photovoltaic cells connected in series and parallel to form photovoltaic power sources of different capacities, the output current of the photovoltaic cell is:

[0160] (2)

[0161] in:

[0162] (3)

[0163] (4)

[0164] Among them, I p ,I ph ,I p0 ,I sh ,I d They are the photovoltaic cell output current, photocurrent, diode reverse saturation current, leakage current and the current flowing through the diode, in A; q is the electron charge, taken as ; Up is the open circuit voltage of the photovoltaic cell, in V; R ss , R sh are the equivalent series resistance and parallel resistance, in Ω; A is the ideal quality factor of the diode; k is the Boltzmann constant, which is ; T pv is the photovoltaic cell temperature, in K; exp() is the exponential function;

[0165] The photovoltaic power generation unit is connected through a Boost circuit and uses maximum power point tracking control;

[0166] The fuel cell uses a PEM fuel cell, and the internal voltage equation corresponding to the PEM fuel cell is:

[0167] (5)

[0168] Among them, E fc is the voltage inside the fuel cell; E0 is the standard reference potential under standard conditions, in V; R is the gas constant, with a value of 8.3143 J / ( ), T fc is the fuel cell temperature, in K; F is the Faraday constant, with a value of 96485C / mol; is the hydrogen partial pressure, in Pa; is the oxygen partial pressure, in pa; E d,fc The delayed effect of fuel and oxidant on voltage; the fuel cell output voltage is:

[0169] (6)

[0170] in:

[0171] (7)

[0172] (8)

[0173] (9)

[0174] Among them, U fc,act , U fc,ohm , U fc,conc and U fc is the polarization voltage, ohmic voltage, concentration voltage, and output voltage of the fuel cell, in V; i fcd is the unit current density of the fuel cell, in A / cm 2 ; a, b are the constants of the Tafel equation, in V / K; R fc,ohm is the resistance of the polymer film, the resistance between the film and the electrode, and the integrated resistance between the electrodes, in Ω; z is the number of participating electrons; i fc,limitis the limiting current density of the fuel cell, in A / cm 2 ;

[0175] Multiple fuel cells are connected in series and parallel to form a fuel cell stack, and its output power P fc for:

[0176] (10)

[0177] in:

[0178] (11)

[0179] (12)

[0180] Among them, u fc is the fuel cell stack voltage, in V; i fc is the fuel cell stack current, in A; N fcs 、N fcp are the number of fuel cells in series and parallel respectively; I fc is the fuel cell current, in A;

[0181] The fuel cell provides power to the DC bus through the Boost circuit, and the differential equation is established:

[0182] (13)

[0183] in:

[0184] (14)

[0185] Among them, i fcL is the inductor current in the boost circuit connected to the fuel cell, in A; C fc1 The low-voltage side capacitance of the boost circuit connected to the fuel cell, in F; L fc is the inductance of the boost circuit connected to the fuel cell, in H; D fc is the duty cycle of the boost circuit controller connected to the fuel cell;

[0186] A PEM electrolyzer is used, which consists of multiple electrolytic chambers connected in series, and multiple groups of electrolytic cells are connected in parallel to a DC power supply;

[0187] The voltage-current equation of the electrolysis chamber terminal voltage at any temperature is:

[0188] (15)

[0189] in:

[0190] (16)

[0191] (17)

[0192] (18)

[0193] Among them, E el , U el,act , U el,ohm and U el They are the open circuit voltage, polarization overvoltage, ohmic polarization voltage and terminal voltage of the electrolytic cell, in V; α H2O is the water activity between the anode and the electrolyte, here it is 1; T el is the electrolyte temperature, in K; α is the transfer coefficient; i eld is the electrolytic cell current density; i el,0 Electrolytic cell exchange current density; R el,ohm is the membrane resistance;

[0194] Multiple electrolytic chambers are connected in series and parallel to form an electrolytic cell stack, which consumes power P el for:

[0195] (19)

[0196] in:

[0197] (20)

[0198] (twenty one)

[0199] Among them, u el is the electrolysis voltage, in V; i el is the electrolysis current, in A; N els 、N elp are the number of electrolytic cells connected in series and in parallel respectively; I el is the electrolytic cell current, in A;

[0200] The DC bus provides electrical energy for the electrolyzer to produce hydrogen through the Buck circuit, and the differential equation is established as follows:

[0201] (twenty two)

[0202] Among them, i elL is the inductor current in the Buck circuit connected to the electrolytic cell, in A; C el2 The low-voltage side capacitance of the Buck circuit connected to the electrolytic cell, in F; L el is the inductance of the Buck circuit connected to the electrolytic cell, in H; D el is the duty cycle of the Buck circuit controller connected to the electrolyzer;

[0203] A lead-acid battery is selected as the electrochemical energy storage device, and its terminal voltage is:

[0204] (twenty three)

[0205] Among them, the controlled voltage source equation is:

[0206] (twenty four)

[0207] Among them, u bat 、E bat 、E bat0 and K bat They are the battery terminal voltage, internal potential, no-load voltage and polarization voltage, in V; Q n is the battery capacity, in Ah; I bat is the battery charge and discharge current, in A; B1 is the voltage change coefficient, in V; B2 is the capacity change coefficient, in ; R eq is the equivalent internal resistance of the battery, in Ω;

[0208] By the battery state of charge S bat The expression for remaining capacity is:

[0209] (25)

[0210] Among them, S bat0 is the initial charge state of the battery, unit is %;

[0211] The battery is charged and discharged via a bidirectional Buck-Boost circuit, and the differential equation is established:

[0212] (1) Buck working status:

[0213] (26)

[0214] (2) Boost working status:

[0215] (27)

[0216] Among them, i batL is the inductor current in the bidirectional Buck-Boost circuit connected to the battery, in A; C bat2 The low-voltage side capacitor of the bidirectional Buck-Boost circuit connected to the battery, in F; L bat is the inductance of the bidirectional Buck-Boost circuit connected to the battery, in H; D bat1It is the duty cycle of the high-side switch controller of the bidirectional Buck-Boost circuit connected to the battery.

[0217] Furthermore, the integrated control module realizes:

[0218] Clarify the basic principles and framework of collaborative control theory, determine the coordination mechanism and information interaction mode between multi-unit models, and analyze the application of collaborative control theory in complex energy systems;

[0219] Consider the microgrid as an n-dimensional nonlinear system as shown in formula (28):

[0220] (28)

[0221] Where x is the system state vector; d is the control input; t is time; f is the function expression of x, d, and t;

[0222] Cooperative control is based on the derivation of control laws based on the nonlinear system model, including the definition of macro variables and the solution of control quantities. The macro variable Ψ(x) is a function of the state variable in the nonlinear system, and the state variable is selected according to the purpose to be achieved by the control system. Through cooperative control, the macro variable can converge and remain on the manifold Ψ(x)=0. The dynamic equation of the macro variable tending to the manifold after the system disturbance is described as:

[0223] (29)

[0224] Where N is a time constant, which determines the convergence speed of the macro variables to the manifold, and N>0;

[0225] Substituting the constructed macro variables into equation (28) into equation (29) yields:

[0226] (30)

[0227] By solving equation (29), we can obtain the solution of d. Under the action of d, the nonlinear system recovers stability from any state after being disturbed, and the macro variables move toward the manifold, gradually approaching the equilibrium point of the system.

[0228] Solving the ordinary differential equation (28) yields the macro variables:

[0229] (31)

[0230] Among them, Ψ(0) is the initial state of the macro variable;

[0231] According to the principles of collaborative control theory, the coordinated control strategy of the system is designed and constructed, including:

[0232] (1) Fuel cell control design:

[0233] The relationship between the input voltage and output voltage in the Boost circuit where the fuel cell is located is:

[0234] (32)

[0235] Combined with the differential equation of the Boost circuit, the macro control variables are designed as follows:

[0236] (33)

[0237] Among them, u fcref is the input voltage reference value of the Boost circuit, in V; k1 is the positive coefficient; i fcLref is the reference value of the inductor current of the Boost circuit, which is determined by the inductor current i fcL The value after low-pass filtering is determined in A;

[0238] Derivative (33) and substitute it into (29), we get the dynamic process of macro variable Ψ1 tending to the manifold:

[0239] (34)

[0240] Wherein, N1 is the time constant of the coordinated control of the fuel cell module;

[0241] According to equations (13) and (34), the duty cycle D of the boost circuit controller where the fuel cell is located is obtained: fc ’ The solution is:

[0242] (35)

[0243] When the system is in steady state operation, u fc =u fcref 、i fcL =i fcLref , from formula (35) we get D fc ’ is a constant, the fuel cell power is constant, and when the bus voltage fluctuates, D fc ’ The L based on the Boost circuit changes accordingly to achieve fuel cell power response. fc , C fc1 Parameters, N1 and k1 are determined according to the simulation operation, and the power of the fuel cell when the system is stable before and after the disturbance is obtained;

[0244] To achieve the change of fuel cell power in response to bus voltage changes, D fc ’ The value of satisfies the interval [0,1], which controls the on / off of the Boost circuit switch;

[0245] By modulating Dfc ’ The corresponding fuel cell power is:

[0246] (36)

[0247] (2) Electrolyzer control design:

[0248] The relationship between the input voltage and output voltage in the Buck circuit where the electrolyzer is located is:

[0249] (37)

[0250] In order to ensure that the output power of the electrolyzer is equal to the set power, the macro variables are designed in combination with the Buck circuit differential equation as follows:

[0251] (38)

[0252] Among them, u elref is the reference value of the Buck circuit output voltage, in V; k2 is a positive coefficient; i elLref is the reference value of the inductor current of the Buck circuit, which is determined by the inductor current i elL The value after low-pass filtering is determined in A;

[0253] Derivative (38) and substitute it into (29), we get the dynamic process of macro variable Ψ2 tending to the manifold:

[0254] (39)

[0255] Wherein, N2 is the time constant of the coordinated control of the electrolyzer modules;

[0256] According to equations (22) and (39), the duty cycle D of the Buck circuit controller where the electrolyzer is located is obtained el The solution is:

[0257] (40)

[0258] When the system is in steady state operation, u el =u elref 、i elL =i elLref , we can get D from formula (40): el is a constant, the electrolytic cell power is constant, and when the bus voltage fluctuates, D el The L based on Buck circuit el , C el2 Parameters, N2, k2 are determined according to the simulation operation, and the power of the electrolyzer when the system is stable before and after the disturbance is obtained; in order to change the electrolyzer power in response to the bus voltage change, D elThe value of satisfies the interval [0,1], which controls the opening and closing of the Buck circuit switch;

[0259] By modulating D el The corresponding electrolyzer power is:

[0260] (41)

[0261] (3) Battery control design:

[0262] ①Battery in Buck state:

[0263] Set the bus power as the difference between the power supply power and the load power, and use the mathematical model of each unit to calculate the formula Transform it and get:

[0264] (42)

[0265] In order to suppress the bus voltage change, the linear combination of battery power deviation and bus voltage deviation is selected to design the macro variable as:

[0266] (43)

[0267] Among them, u batref is the voltage reference value of the battery, in V; k3 and k4 are positive coefficients; i batLref is the reference value of the inductor current of the Buck-Boost circuit, which is determined by the inductor current i batL The value after low-pass filtering is determined in A; u dcref is the DC bus reference voltage, in V;

[0268] Deriving equation (43) and substituting it into equation (29), we obtain:

[0269] (44)

[0270] Among them, N3 is the time constant of cooperative control of the battery module in Buck state;

[0271] According to equations (26), (42) and (44), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained: bat1 The solution is:

[0272] (45)

[0273] ②Battery in Boost state:

[0274] In Boost mode, the battery is equivalent to a power source, and the expression for bus power balance becomes:

[0275] (46)

[0276] The macro variables of linear combination design are similar to the structure of Buck mode, as follows:

[0277] (47)

[0278] Among them, k5 and k6 are positive coefficients;

[0279] Deriving equation (47) and substituting it into equation (29), we obtain:

[0280] (48)

[0281] Wherein, N4 is the time constant of cooperative control of the battery module in the Boost state;

[0282] According to equations (27), (46) and (48), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained bat1 The solution is:

[0283] (49)

[0284] When the system is running in steady state, i bat =i batref 、u bat =u batref 、u dc =u dcref , fuel cell, and electrolyzer power change is 0, and the battery duty cycle is obtained from equations (45) and (49): , the power of the fuel cell, electrolyzer and battery will not change; from equation (47) and equation (49), we can get D based on the collaborative control theory design bat1 With D el , D fc ’ and u dc There is a coupling relationship, the four influence each other, when u dc When fluctuation occurs, D bat1 , D el and D fc ’ Corresponding changes occur: when the DC bus voltage is higher than the rated value, the power surplus in the microgrid is reduced by increasing the electrolyzer power and the charging power of the battery; on the contrary, when the bus voltage is lower than the rated value, the system power is supplemented by increasing the fuel cell power and the discharging power of the battery.

[0285] Furthermore, the control stability verification module implements:

[0286] In order to verify the stability of the proposed control strategy in the DC microgrid under small disturbances, a small signal model of the microgrid is established. First, the small signal models of the electrolyzer Buck circuit, the fuel cell Boost circuit, and the battery DC / DC loop are established respectively. Then, the photovoltaic and DC loads are regarded as constant power units, and the small signal model of the DC microgrid is obtained from the DC bus KCL relationship as shown in Equation (50):

[0287] (50)

[0288] Among them, the DC microgrid small signal model variables ,in A is a variable including voltage and current; DC is the coefficient matrix;

[0289] The DC microgrid small signal model constructed based on formula (50) is expressed by the coefficient matrix A DC Analyze the characteristic roots of the system; the collaborative control coefficient N is a time constant that determines the speed at which the macro variables converge to the manifold; in the system stability analysis, determine the value range of the control parameters.

[0290] In a third aspect, the present invention further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned method for collaborative optimization control of an electric-hydrogen energy hub when executing the program.

[0291] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-mentioned method for coordinated optimization control of an electric-hydrogen energy hub.

[0292] Beneficial effects:

[0293] 1. The present invention systematically constructs a precise model of each unit and its connecting circuit, accurately depicts the dynamic characteristics of the electric hydrogen energy hub, and provides a more realistic basis for the design and optimization of control strategies.

[0294] 2. The present invention is based on the collaborative control theory. The constructed electric hydrogen energy hub model can be directly applied in the control design without linearization processing. It can effectively cope with the complex nonlinear characteristics and dynamic operating conditions of the system, and improve the applicability and robustness of the control strategy.

[0295] 3. Based on verifying the stability of the control strategy, the present invention further optimizes the control parameters to ensure that the electric hydrogen energy hub can quickly reach a stable state and avoid overshoot, thereby improving the dynamic performance and operating efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0296] Figure 1 This is a flow chart of an integrated control method for an electric-hydrogen energy hub based on collaborative control theory in an embodiment of the present invention;

[0297] Figure 2 is a schematic diagram of a Boost circuit connected to a fuel cell in an embodiment of the present invention;

[0298] Figure 3 Schematic diagram of a Buck circuit connected to an electrolytic cell in an embodiment of the present invention;

[0299] Figure 4 Schematic diagram of a bidirectional Buck-Boost circuit connected to a battery in an embodiment of the present invention. DETAILED DESCRIPTION

[0300] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0301] In the description of the present invention, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. used in the present invention to indicate the orientation or position relationship is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0302] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0303] The present invention proposes an integrated control method and system for an electric-hydrogen energy hub based on collaborative control theory. Aiming at the scenarios of increasing the penetration rate of new energy and combining the power system with hydrogen energy, the method aims to give full play to the potential of each device and improve the overall efficiency and safety of the system. Combined with the structure and characteristics of the electric-hydrogen hub system, a comprehensive control scheme based on collaborative control is proposed.

[0304] like Figure 1 As shown, an integrated control method of an electric hydrogen energy hub based on collaborative control theory provided by an embodiment of the present invention includes the following steps:

[0305] Step S1: construct an electric hydrogen energy hub structure that couples a photovoltaic power generation unit, a hydrogen energy unit, and a battery unit to a DC bus, and establish a model of each unit;

[0306] Step S2: Determine the output of each unit through each unit model, and design a coordinated control strategy for the electric-hydrogen fusion hub based on coordinated control theory;

[0307] Step S3: construct a small signal model based on each unit model, verify the stability of the proposed collaborative control strategy under small disturbances of the DC microgrid through the small signal model, and determine the optimal values ​​of each control parameter of the collaborative control strategy.

[0308] In an embodiment, the step S1 specifically includes:

[0309] Step S11: construct an electric hydrogen energy hub structure according to the composition of the electric hydrogen energy hub and the connection method between the equipment, wherein the photovoltaic power generation unit, fuel cell, electrolyzer and battery are connected to the DC bus through the inverter.

[0310] The structure of the electric hydrogen energy hub includes photovoltaic power generation units, batteries, fuel cells, electrolyzers, hydrogen storage tanks, converters and loads. The photovoltaic power generation unit is responsible for capturing solar energy and continuously inputting energy into the system; when there is excess power in the system, the electrolyzer uses the remaining power to produce hydrogen, which is stored in the hydrogen storage tank for use by the hydrogen load. When the output of new energy is low, the fuel cell converts the hydrogen in the hydrogen storage tank into electrical energy for use by the electrical load, thereby maximizing the utilization efficiency of new energy. The battery provides support for the electrolyzer and fuel cell, helping to maintain the stability of the DC bus voltage.

[0311] In the electric hydrogen energy hub structure, the energy inflow and outflow of each unit will cause fluctuations in the DC bus voltage. In order to maintain the stability of the DC bus voltage and the balance of the system input and output power, the control center issues control instructions based on the operating status of each unit to coordinate the operation of each unit. The voltage dynamic equation of the DC bus capacitor is as follows:

[0312] (1)

[0313] Among them, C dc 、u dc They are the DC bus capacitance and voltage, in V; P pv , P fc , P el , P bat , Pload They are the power from photovoltaics flowing into the DC bus, the power from fuel cells flowing into the DC bus, the power from electrolyzers flowing into the DC bus, the power from batteries flowing into the DC bus, and the power from loads flowing into the DC bus, in W; t represents time.

[0314] Step S12: Establishing mathematical models of photovoltaic power generation units, fuel cells, electrolyzers, batteries and their connection circuits according to the types and technical characteristics of each unit.

[0315] The photocurrent generated by the photovoltaic cell under illumination is represented by a current source, the PN junction characteristics are represented by a diode, the current flowing through the diode is the PN junction diffusion current, and the output current of the photovoltaic cell is:

[0316] (2)

[0317] in:

[0318] (3)

[0319] (4)

[0320] Among them, I p ,I ph ,I p0 ,I sh ,I d They are the photovoltaic cell output current, photocurrent, diode reverse saturation current, leakage current, and current flowing through the diode, in A; q is the electron charge, which is taken as ; U p is the open circuit voltage of the photovoltaic cell, in V; R ss , R sh are the equivalent series resistance and parallel resistance, in Ω; A is the ideal quality factor of the diode; k is the Boltzmann constant, which is ; T pv is the photovoltaic cell temperature, in K; exp() is the exponential function.

[0321] The photovoltaic power generation unit is connected through the Boost circuit and uses the Maximum Power Point Tracking (MPPT) control to achieve accurate tracking of the maximum power point, ensuring that the power generation system always operates at the maximum power point, thereby reducing energy waste. Therefore, there is no need to adjust its operating state during the coordinated control process, so there is no need to establish a circuit model connected to it.

[0322] PEM fuel cells have outstanding advantages such as fast start-up and operation at low temperatures, solid electrolytes that are not easily lost, long life, high specific power and specific energy, etc., and are the most popular fuel cells. Therefore, PEM fuel cells are selected.

[0323] The internal voltage equation corresponding to the PEM fuel cell is:

[0324] (5)

[0325] Among them, E fc is the voltage inside the fuel cell; E0 is the standard reference potential under standard conditions, in V; R is the gas constant, with a value of 8.3143 J / ( ), T fc is the fuel cell temperature, in K; F is the Faraday constant, with a value of 96485C / mol; is the hydrogen partial pressure, in Pa; is the oxygen partial pressure, in pa; E d,fc Delayed effect voltage for fuel and oxidizer;

[0326] The fuel cell output voltage is:

[0327] (6)

[0328] in:

[0329] (7)

[0330] (8)

[0331] (9)

[0332] Among them, U fc,act , U fc,ohm , U fc,conc and U fc is the polarization voltage, ohmic voltage, concentration voltage, and output voltage of the fuel cell, in V; i fcd is the unit current density of the fuel cell, in A / cm 2 ; a, b are the constants of the Tafel equation, in V / K; R fc,ohm is the resistance of the polymer film, the resistance between the film and the electrode, and the integrated resistance between the electrodes, in Ω; z is the number of participating electrons; i fc,limit is the limiting current density of the fuel cell, in A / cm 2 ;

[0333] Multiple fuel cells are connected in series and parallel to form a fuel cell stack, and its output power P fc for:

[0334] (10)

[0335] in:

[0336] (11)

[0337] (12) Where u fc is the fuel cell stack voltage, in V; i fc is the fuel cell stack current, in A; N fcs 、N fcp are the number of fuel cells in series and parallel respectively; I fc is the fuel cell current, in A;

[0338] The boost circuit connects the fuel cell to the switch element and controls the switch state of the switch element to adjust the current. When the switch is turned on, the current flows through the inductor (L fc ) stores energy; when the switch is turned off, the inductor releases the stored energy and the current flows through the diode (D fc ) flows to the output terminal. The output terminal is connected to the output capacitor (C fc2 ), which is used to smooth the voltage and provide a stable output voltage higher than the input voltage to the DC bus. The equivalent circuit of the Boost circuit is as follows Figure 2 shown.

[0339] According to its working principle, the following differential equation can be established:

[0340] (13)

[0341] in:

[0342] (14)

[0343] Among them, i fcL is the inductor current in the boost circuit connected to the fuel cell, in A; C fc1 The low-voltage side capacitance of the boost circuit connected to the fuel cell, in F; L fc is the inductance of the boost circuit connected to the fuel cell, in H; D fc is the duty cycle of the boost circuit controller connected to the fuel cell.

[0344] Compared with other water electrolysis hydrogen production technologies, PEM electrolyzers have the advantages of high efficiency, energy saving, low noise, etc. Therefore, PEM electrolyzers are used as water electrolysis hydrogen production equipment. The commonly used PEM electrolyzers are composed of multiple electrolysis chambers connected in series, and multiple groups of electrolyzers are connected in parallel to a DC power supply.

[0345] The terminal voltage of the electrolysis chamber mainly includes reversible voltage, ohmic overvoltage and polarization overvoltage. Its voltage-current equation at any temperature is:

[0346] (15)

[0347] in:

[0348] (16)

[0349] (17)

[0350] (18)

[0351] Among them, E el , U el,act , U el,ohm and U el They are the open circuit voltage, polarization overvoltage, ohmic polarization voltage and terminal voltage of the electrolytic cell, in V; α H2O is the water activity between the anode and the electrolyte, here it is 1; T el is the electrolyte temperature, in K; α is the transfer coefficient; i eld is the electrolytic cell current density; i el,0 Electrolytic cell exchange current density; R el,ohm is the membrane resistance;

[0352] Multiple electrolytic chambers are connected in series and parallel to form an electrolytic cell stack, which consumes power P el for:

[0353] (19)

[0354] in:

[0355] (20)

[0356] (twenty one)

[0357] Among them, u el is the electrolysis voltage, in V; i el is the electrolysis current, in A; N els 、N elp are the number of electrolytic cells connected in series and in parallel respectively; I el is the electrolytic cell current, in A;

[0358] The Buck circuit connects the DC bus to a switching element to control the current flow. When the switch is turned on, the current flows through the inductor (L el ), storing energy; when the switch is turned off, the inductor releases the stored energy and current flows through the diode (D el) flows to the output terminal. The output terminal is connected to the output capacitor (C el2 ), which is used to smooth the voltage and provide a stable output voltage lower than the input voltage for the electrolyzer. The equivalent circuit of the Buck circuit is as follows Figure 3 shown.

[0359] According to its working principle, the following differential equation can be established:

[0360] (twenty two)

[0361] Among them, i elL is the inductor current in the Buck circuit connected to the electrolytic cell, in A; C el2 The low-voltage side capacitance of the Buck circuit connected to the electrolytic cell, in F; L el is the inductance of the Buck circuit connected to the electrolytic cell, in H; D el is the duty cycle of the Buck circuit controller connected to the electrolyzer.

[0362] Lead-acid battery technology is relatively mature, has high reliability, large capacity and good economy, so lead-acid batteries are used as electrochemical energy storage devices.

[0363] The battery equivalent model consists of a controlled voltage source related to the battery current and a resistor in series. The battery terminal voltage is:

[0364] (twenty three)

[0365] Among them, the controlled voltage source equation is:

[0366] (twenty four)

[0367] Among them, u bat 、E bat 、E bat0 and K bat They are the battery terminal voltage, internal potential, no-load voltage, and polarization voltage, in V; Q n is the battery capacity, in Ah; I bat is the battery charge and discharge current, in A; B1 is the voltage change coefficient, in V; B2 is the capacity change coefficient, in ; R eq is the equivalent internal resistance of the battery, in Ω;

[0368] The battery state of charge S bat The expression for remaining capacity is:

[0369] (25)

[0370] Among them, Sbat0 is the initial state of charge of the battery, %.

[0371] The bidirectional Buck-Boost circuit connects the battery and the inductor through a switching element, and adjusts the current flow according to the relationship between the input voltage and the output voltage. In Buck mode, the switching element S bat2 Keep off, switch S bat1 When the switch S is turned on, the current flows through the inductor to store energy; bat1 When turned off, the inductor releases the stored energy through S bat2 In Boost mode, the switching element S bat1 Keep off, switch S bat2 When the switch S is turned on, the current flows through the inductor to store energy; bat2 When turned off, the inductor releases the stored energy through S bat1 The diode in the output terminal supplies power to the output terminal. The output terminal is connected to the output capacitor (C bat1 ), which is used to smooth the output voltage and ensure a stable voltage for the DC bus. The equivalent circuit of the bidirectional Buck-Boost circuit is as follows Figure 4 shown.

[0372] According to its working principle, the following differential equation can be established:

[0373] (1) Buck working status:

[0374] (26)

[0375] (2) Boost working status:

[0376] (27)

[0377] Among them, i batL is the inductor current in the bidirectional Buck-Boost circuit connected to the battery, in A; C bat2 The low-voltage side capacitor of the bidirectional Buck-Boost circuit connected to the battery, in F; L bat is the inductance of the bidirectional Buck-Boost circuit connected to the battery, in H; D bat1 It is the duty cycle of the high-side switch controller of the bidirectional Buck-Boost circuit connected to the battery.

[0378] After step S1, the overall structure of the electric hydrogen hub system and the mathematical models of each unit and its connection circuit are established.

[0379] In an embodiment, the step S2 specifically includes:

[0380] Step S21: clarify the basic principles and framework of collaborative control theory, systematically explain its core concepts, including the coordination mechanism and information interaction mode among multiple systems, and analyze the application of collaborative control theory in complex energy systems, laying a theoretical foundation for the subsequent control strategy design;

[0381] Collaborative control theory is the application of synergetics and self-organization theory in the field of control. Its core idea is to coordinate the behaviors of various units within the system based on the self-organizing ability of the open system, and to guide the participating units to cooperate with each other when the system is disturbed or changes its operating mode, so as to achieve the goal of restoring system stability.

[0382] Consider the microgrid as an n-dimensional nonlinear system as shown in equation (28).

[0383] (28)

[0384] Among them, x is the system state vector; d is the control input; t is time; f is the function expression of x, d, and t.

[0385] Cooperative control can derive control laws based on nonlinear system models. The design process mainly includes defining macro variables and solving control quantities. The macro variable Ψ(x) is a function of the state variables in the nonlinear system. Its construction is the key to achieving cooperative control. The state variables need to be selected according to the purpose of the control system. In addition, through cooperative control, the macro variables can converge and remain on the manifold Ψ(x)=0. The dynamic equation of the macro variables tending to the manifold after the system disturbance can be described as:

[0386] (29)

[0387] Where N is a time constant that determines the convergence speed of the macro variables toward the manifold, and N>0.

[0388] Substituting the constructed macro variables into equation (28) into equation (29) yields:

[0389] (30)

[0390] By solving equation (30), we can get the solution of d. Under the action of d, the nonlinear system can recover stability from any state after disturbance, and the macro variables move toward the manifold and gradually approach the equilibrium point of the system. Solving the ordinary differential equation (29), we can get the macro variables as follows:

[0391] (31)

[0392] Among them, Ψ(0) is the initial state of the macro variable.

[0393] It can be seen from formula (31) that the macro variable decays exponentially with N and finally remains on the manifold. N is positively correlated with the dynamic process of the macro variable approaching the manifold. N is set to be much smaller than the system dynamic response time to ensure that the main time in the adjustment process is on the manifold. In order to improve the response speed of the system, N should be reduced as much as possible while maintaining system stability.

[0394] Step S22: Design and construct a coordinated control strategy for the system based on the principles of collaborative control theory. The strategy should fully consider the operating characteristics and interrelationships of each unit, and achieve efficient collaborative operation of the multi-energy system by optimizing control parameters and information interaction, thereby ensuring overall system stability and performance improvement;

[0395] (1) Fuel cell control design:

[0396] The relationship between the input voltage and output voltage in the Boost circuit where the fuel cell is located is:

[0397] (32)

[0398] When the bus voltage fluctuates, the voltage and current of the fuel cell can be adjusted by adjusting the duty cycle, thereby achieving the power response of the fuel cell. To ensure that the output power of the fuel cell is equal to the set target power, the macro control variables are designed as follows in combination with the differential equation of the Boost circuit:

[0399] (33)

[0400] Among them, u fcref is the input voltage reference value of the Boost circuit, in V; k1 is the positive coefficient; i fcLref is the reference value of the inductor current of the Boost circuit, which is determined by the inductor current i fcL The value is determined after low-pass filtering and the unit is A.

[0401] Derivative (33) and substitute it into (29), we get the dynamic process of macro variable Ψ1 tending to the manifold:

[0402] (34)

[0403] Wherein, N1 is the time constant of the coordinated control of the fuel cell module.

[0404] According to equations (13) and (34), the duty cycle D of the boost circuit controller where the fuel cell is located can be obtained: fc ’ The solution is:

[0405] (35)

[0406] When the system is in steady state operation, ufc =u fcref 、i fcL =i fcLref , from formula (36) we get D fc ’ is a constant, the fuel cell power is constant, and when the bus voltage fluctuates, D fc ’ The L based on the Boost circuit changes accordingly to achieve the fuel cell power response. fc , C fc1 Parameters, N1, k1 are determined according to the simulation operation, and the power of the fuel cell when the system is stable before and after the disturbance can be obtained. In order to change the fuel cell power in response to the bus voltage change, D fc ’ The value of should be within the range of [0,1] to control the on / off of the Boost circuit switch. fc ’ The corresponding fuel cell power is:

[0407] (36)

[0408] (2) Electrolyzer control design:

[0409] The relationship between the input voltage and output voltage in the Buck circuit where the electrolyzer is located is:

[0410] (37)

[0411] When the bus voltage fluctuates, the duty cycle can be changed to adjust the electrolytic cell voltage and current to achieve the power response of the electrolytic cell. To ensure that the output power of the electrolytic cell is equal to the set power, the macro variable is designed in combination with the Buck circuit differential equation as follows:

[0412] (38)

[0413] Among them, u elref is the reference value of the Buck circuit output voltage, in V; k2 is a positive coefficient; i elLref is the reference value of the inductor current of the Buck circuit, which is determined by the inductor current i elL The value is determined after low-pass filtering and the unit is A.

[0414] Derivative (39) and substitute it into (30), we get the dynamic process of macro variable Ψ1 tending to the manifold:

[0415] (39)

[0416] Wherein, N2 is the time constant of the coordinated control of the electrolyzer modules.

[0417] According to equations (22) and (39), the duty cycle D of the Buck circuit controller where the electrolyzer is located can be obtained: el The solution is:

[0418] (40)

[0419] When the system is in steady state operation, u el =u elref 、i elL =i elLref , from formula (40) we get D el is a constant, the electrolytic cell power is constant, and when the bus voltage fluctuates, D el The L based on Buck circuit can achieve the power response of electrolyzer. el , C el2 Parameters, according to the simulation run to determine N2, k2, the power of the electrolyzer when the system is stable before and after the disturbance can be obtained. In order to change the electrolyzer power in response to the bus voltage change, D el The value of should be within the range of [0,1] to control the on / off of the Buck circuit switch. el The corresponding electrolyzer power is:

[0420] (41)

[0421] (3) Battery control design:

[0422] ①Battery in Buck state:

[0423] The battery assists the hydrogen energy system in dealing with bus voltage fluctuations caused by power imbalance in the microgrid by adjusting the output power. The bus power is set as the difference between the power source power and the load power. According to the mathematical model of each unit, equation (1) is transformed to obtain:

[0424] (42)

[0425] In order to suppress the bus voltage change, the linear combination of battery power deviation and bus voltage deviation is selected to design the macro variable as:

[0426] (43)

[0427] Among them, u batref is the voltage reference value of the battery, in V; k3 and k4 are positive coefficients; i batLref is the reference value of the inductor current of the Buck-Boost circuit, which is determined by the inductor current i batL The value after low-pass filtering is determined in A; u dcref is the DC bus reference voltage, in V. Derivative (43) and substitute it into (29) to obtain:

[0428] (44)

[0429] Among them, N3 is the time constant of the coordinated control of the battery module in the Buck state.

[0430] According to equations (26), (42) and (44), the duty cycle D of the Buck-Boost circuit controller where the battery is located can be obtained: bat1 The solution is:

[0431] (45)

[0432] ②Battery in Boost state:

[0433] In Boost mode, the battery can be equivalent to a power source, and the expression of bus power balance becomes:

[0434] (46)

[0435] The macro variables of linear combination design are similar to the structure of Buck mode, as follows:

[0436] (47)

[0437] Among them, k5 and k6 are positive coefficients.

[0438] Deriving equation (47) and substituting it into equation (29), we obtain:

[0439] (48)

[0440] Among them, N4 is the time constant of the coordinated control of the battery module in the Boost state.

[0441] According to equations (27), (46) and (48), the duty cycle D of the Buck-Boost circuit controller where the battery is located can be obtained: bat1 The solution is:

[0442] (49)

[0443] When the system is running in steady state, i bat =i batref 、u bat =u batref 、u dc =u dcref , fuel cell, and electrolyzer power change is 0, and the battery duty cycle is obtained from equations (45) and (49): , the power of the fuel cell, electrolyzer and battery will not change. From equations (45) and (49), it can be seen that D designed based on the collaborative control theorybat1 With D el , D fc ’ and u dc There is a coupling relationship, the four influence each other, when u dc When fluctuation occurs, D bat1 , D el and D fc ’ Corresponding changes occur: when the DC bus voltage is higher than the rated value, the power surplus in the microgrid is reduced by increasing the electrolyzer power and the charging power of the battery; on the contrary, when the bus voltage is lower than the rated value, the system power is supplemented by increasing the fuel cell power and the discharging power of the battery.

[0444] After step S2, an integrated control strategy based on coordinated control theory is obtained.

[0445] In an embodiment, the step S3 specifically includes:

[0446] In order to verify the stability of the proposed control strategy under small disturbances in the DC microgrid, a small signal model of the microgrid is established. First, the small signal models of the electrolyzer Buck circuit, the fuel cell Boost circuit, and the battery DC / DC loop are established respectively. Then, the photovoltaic and DC loads are regarded as constant power units, and the small signal model of the DC microgrid is obtained from the DC bus KCL relationship as shown in Equation (50).

[0447] (50)

[0448] Among them, the DC microgrid small signal model variables ,in A is a variable including voltage and current; DC is the coefficient matrix.

[0449] The DC microgrid small signal model constructed based on formula (50) is expressed by the coefficient matrix A DC Analyze the characteristic roots of the system. The collaborative control coefficient N is a time constant that determines the speed at which the macro variables converge to the manifold. In the system stability analysis, the influence of N can be ignored, and the focus of the analysis should be on the control parameter k (i.e. ~ ) on the small signal stability of the system and determine the value range of the control parameter k.

[0450] After step S3, the stability of the proposed control strategy is evaluated and the value range of the control parameter k is determined.

[0451] In summary, the present invention proposes an integrated control method for an electric hydrogen energy hub based on collaborative control theory, which aims to meet the challenges of increasing the penetration rate of new energy and combining the power system with hydrogen energy, so as to give full play to the potential of each device and improve the overall efficiency and safety of the system. This method combines the structure and characteristics of the electric hydrogen hub, analyzes the working principle of the system, first determines the overall architecture and constructs a mathematical model of each unit and its connecting circuit. Subsequently, the application of collaborative control theory in complex systems is deeply understood, and controllers for fuel cells, electrolyzers and batteries are designed based on this theory. Finally, a small signal stability analysis of the control strategy is carried out, and the range of values ​​of the control parameter k is determined, thereby realizing an integrated control strategy based on collaborative control theory.

[0452] The present invention also provides an integrated control system for an electric hydrogen energy hub based on collaborative control theory, comprising the following modules:

[0453] The equipment power calculation module builds an electric hydrogen energy hub structure that couples the photovoltaic power generation unit, hydrogen energy unit, and battery unit to the DC bus, and establishes models for each unit;

[0454] Integrated control module, which determines the output of each unit through each unit model, and designs the coordinated control strategy of the electric-hydrogen fusion hub based on the coordinated control theory;

[0455] The control stability verification module builds a small signal model based on each unit model, verifies the stability of the proposed collaborative control strategy under small disturbances of the DC microgrid through the small signal model, and determines the optimal values ​​of each control parameter of the collaborative control strategy.

[0456] Specifically, the device power calculation module realizes:

[0457] The structure of the electric-hydrogen energy hub is constructed according to the composition of the electric-hydrogen energy hub and the connection between the equipment, in which the photovoltaic power generation unit, the hydrogen energy unit and the battery are connected to the DC bus through the converter;

[0458] The hydrogen energy unit includes a fuel cell and an electrolyzer;

[0459] The voltage dynamic equation of the DC bus capacitor is as follows:

[0460] (1)

[0461] Among them, C dc 、u dc are the DC bus capacitance and voltage respectively, in V; P pv , P fc , P el , P bat , P loadThey are the power from photovoltaics flowing into the DC bus, the power from fuel cells flowing into the DC bus, the power from electrolyzers flowing into the DC bus, the power from batteries flowing into the DC bus, and the power from loads flowing into the DC bus, in W.

[0462] According to the type and technical characteristics of each unit, the mathematical model of photovoltaic power generation unit, fuel cell, electrolyzer, battery and their connection circuit is established;

[0463] For a photovoltaic power generation unit, which is composed of multiple photovoltaic battery cells connected in series and parallel, multiple photovoltaic power generation units are combined into a photovoltaic power generation unit to form photovoltaic power sources of different capacities. The output current of the photovoltaic cell is:

[0464] (2)

[0465] in:

[0466] (3)

[0467] (4)

[0468] Among them, I p ,I ph ,I p0 ,I sh ,I d They are the output current of the photovoltaic cell, the photocurrent, the reverse saturation current of the diode, the leakage current and the current flowing through the diode, in A; q is the electron charge, which is taken as ; U p is the open circuit voltage of the photovoltaic cell, in V; R ss , R sh are the equivalent series resistance and parallel resistance, in Ω; A is the ideal quality factor of the diode; k is the Boltzmann constant, which is ; T pv is the temperature of the photovoltaic cell, in K; exp() is an exponential function;

[0469] The photovoltaic power generation unit is connected through a Boost circuit and uses maximum power point tracking control;

[0470] The fuel cell uses a PEM fuel cell, and the internal voltage equation corresponding to the PEM fuel cell is:

[0471] (5)

[0472] Among them, E fc is the voltage inside the fuel cell; E0 is the standard reference potential under standard conditions, in V; R is the gas constant, with a value of 8.3143 J / ( ), T fcis the fuel cell temperature, in K; F is the Faraday constant, with a value of 96485C / mol; is the hydrogen partial pressure, in Pa; is the oxygen partial pressure, in pa; E d,fc Delayed effect voltage for fuel and oxidizer;

[0473] The fuel cell output voltage is:

[0474] (6)

[0475] in:

[0476] (7)

[0477] (8)

[0478] (9)

[0479] Among them, U fc,act , U fc,ohm , U fc,conc and U fc is the polarization voltage, ohmic voltage, concentration voltage, and output voltage of the fuel cell, in V; i fcd is the unit current density of the fuel cell, in A / cm 2 ; a, b are the constants of the Tafel equation, in V / K; R fc,ohm is the resistance of the polymer film, the resistance between the film and the electrode, and the integrated resistance between the electrodes, in Ω; z is the number of participating electrons; i fc,limit is the limiting current density of the fuel cell, in A / cm 2 ;

[0480] Multiple fuel cells are connected in series and parallel to form a fuel cell stack, and its output power P fc for:

[0481] (10)

[0482] in:

[0483] (11)

[0484] (12)

[0485] Among them, u fc is the fuel cell stack voltage, in V; i fc is the fuel cell stack current, in A; N fcs 、N fcp are the number of fuel cells in series and parallel respectively; I fcis the fuel cell current, in A;

[0486] The fuel cell provides power to the DC bus through the Boost circuit, and the differential equation is established:

[0487] (13)

[0488] in:

[0489] (14)

[0490] Among them, i fcL is the inductor current in the boost circuit connected to the fuel cell, in A; C fc1 The low-voltage side capacitance of the boost circuit connected to the fuel cell, in F; L fc is the inductance of the boost circuit connected to the fuel cell, in H; D fc is the duty cycle of the boost circuit controller connected to the fuel cell;

[0491] A PEM electrolyzer is used, which consists of multiple electrolytic chambers connected in series, and multiple groups of electrolytic cells are connected in parallel to a DC power supply;

[0492] The voltage-current equation of the electrolysis chamber terminal voltage at any temperature is:

[0493] (15)

[0494] in:

[0495] (16)

[0496] (17)

[0497] (18)

[0498] Among them, E el , U el,act , U el,ohm and U el They are the open circuit voltage, polarization overvoltage, ohmic polarization voltage and terminal voltage of the electrolytic cell, in V; α H2O is the water activity between the anode and the electrolyte, here it is 1; T el is the electrolyte temperature, in K; α is the transfer coefficient; i eld is the electrolytic cell current density; i el,0 Electrolytic cell exchange current density; R el,ohm is the membrane resistance;

[0499] Multiple electrolytic chambers are connected in series and parallel to form an electrolytic cell stack, which consumes power P el for:

[0500] (19)

[0501] in:

[0502] (20)

[0503] (twenty one)

[0504] Among them, u el is the electrolysis voltage, in V; i el is the electrolysis current, in A; N els 、N elp are the number of electrolytic cells connected in series and in parallel respectively; I el is the electrolytic cell current, in A;

[0505] The DC bus provides electrical energy for the electrolyzer to produce hydrogen through the Buck circuit, and the differential equation is established as follows:

[0506] (twenty two)

[0507] Among them, i elL is the inductor current in the Buck circuit connected to the electrolytic cell, in A; C el2 The low-voltage side capacitance of the Buck circuit connected to the electrolytic cell, in F; L el is the inductance of the Buck circuit connected to the electrolytic cell, in H; D el is the duty cycle of the Buck circuit controller connected to the electrolyzer;

[0508] A lead-acid battery is selected as the electrochemical energy storage device, and its terminal voltage is:

[0509] (twenty three)

[0510] Among them, the controlled voltage source equation is:

[0511] (twenty four)

[0512] Among them, u bat 、E bat 、E bat0 and K bat They are the battery terminal voltage, internal potential, no-load voltage and polarization voltage, in V; Q n is the battery capacity, in Ah; I bat is the battery charge and discharge current, in A; B1 is the voltage change coefficient, in V; B2 is the capacity change coefficient, in ; R eq is the equivalent internal resistance of the battery, in Ω;

[0513] The battery state of charge S bat The expression for remaining capacity is:

[0514] (25)

[0515] Among them, S bat0 is the initial state of charge of the battery, in %;

[0516] The battery is charged and discharged via a bidirectional Buck-Boost circuit, and the differential equation is established:

[0517] (1) Buck working status:

[0518] (26)

[0519] (2) Boost working status:

[0520] (27)

[0521] Among them, i batL is the inductor current in the bidirectional Buck-Boost circuit connected to the battery, in A; C bat2 The low-voltage side capacitor of the bidirectional Buck-Boost circuit connected to the battery, in F; L bat is the inductance of the bidirectional Buck-Boost circuit connected to the battery, in H; D bat1 It is the duty cycle of the high-side switch controller of the bidirectional Buck-Boost circuit connected to the battery.

[0522] Specifically, the integrated control module realizes:

[0523] Clarify the basic principles and framework of collaborative control theory, determine the coordination mechanism and information interaction mode among multiple systems, and analyze the application of collaborative control theory in complex energy systems;

[0524] Consider the microgrid as an n-dimensional nonlinear system as shown in formula (28):

[0525] (28)

[0526] Where x is the system state vector; d is the control input; t is time; f is the function expression of x, d, and t;

[0527] Cooperative control is based on the derivation of control laws based on the nonlinear system model, including the definition of macro variables and the solution of control quantities. The macro variable Ψ(x) is a function of the state variable in the nonlinear system, and the state variable is selected according to the purpose to be achieved by the control system. Through cooperative control, the macro variable can converge and remain on the manifold Ψ(x)=0. The dynamic equation of the macro variable tending to the manifold after the system disturbance is described as:

[0528] (29)

[0529] Where N is a time constant, which determines the convergence speed of the macro variables to the manifold, and N>0;

[0530] Substituting the constructed macro variables into equation (28) into equation (29) yields:

[0531] (30)

[0532] By solving equation (29), we can obtain the solution of d. Under the action of d, the nonlinear system recovers stability from any state after being disturbed, and the macro variables move toward the manifold, gradually approaching the equilibrium point of the system.

[0533] Solving the ordinary differential equation (28) yields the macro variables:

[0534] (31)

[0535] Among them, Ψ(0) is the initial state of the macro variable;

[0536] According to the principles of collaborative control theory, the coordinated control strategy of the system is designed and constructed, including:

[0537] (1) Fuel cell control design:

[0538] The relationship between the input voltage and output voltage in the Boost circuit where the fuel cell is located is:

[0539] (32)

[0540] Combined with the differential equation of the Boost circuit, the macro control variables are designed as follows:

[0541] (33)

[0542] Among them, u fcref is the input voltage reference value of the Boost circuit, in V; k1 is the positive coefficient; i fcLref is the reference value of the inductor current of the Boost circuit, which is determined by the inductor current i fcL The value after low-pass filtering is determined in A;

[0543] Derivative (33) and substitute it into (29), we get the dynamic process of macro variable Ψ1 tending to the manifold:

[0544] (34)

[0545] Wherein, N1 is the time constant of the coordinated control of the fuel cell module;

[0546] According to equations (13) and (34), the duty cycle D of the boost circuit controller where the fuel cell is located is obtained: fc ’ The solution is:

[0547] (35)

[0548] When the system is in steady state operation, u fc =u fcref 、i fcL =i fcLref , from formula (35) we get D fc ’ is a constant, the fuel cell power is constant, and when the bus voltage fluctuates, D fc ’ The L based on the Boost circuit changes accordingly to achieve fuel cell power response. fc , C fc1 Parameters, N1 and k1 are determined according to the simulation operation, and the power of the fuel cell when the system is stable before and after the disturbance is obtained;

[0549] To achieve the change of fuel cell power in response to bus voltage changes, D fc ’ The value of satisfies the interval [0,1], which controls the on / off of the Boost circuit switch;

[0550] By modulating D fc ’ The corresponding fuel cell power is:

[0551] (36)

[0552] (2) Electrolyzer control design:

[0553] The relationship between the input voltage and output voltage in the Buck circuit where the electrolyzer is located is:

[0554] (37)

[0555] In order to ensure that the output power of the electrolyzer is equal to the set power, the macro variables are designed in combination with the Buck circuit differential equation as follows:

[0556] (38)

[0557] Among them, u elref is the reference value of the Buck circuit output voltage, in V; k2 is a positive coefficient; i elLref is the reference value of the inductor current of the Buck circuit, which is determined by the inductor current i elL The value after low-pass filtering is determined in A;

[0558] Derivative (38) and substitute it into (29), we get the dynamic process of macro variable Ψ2 tending to the manifold:

[0559] (39)

[0560] Wherein, N2 is the time constant of the coordinated control of the electrolyzer modules;

[0561] According to equations (22) and (39), the duty cycle D of the Buck circuit controller where the electrolyzer is located is obtained el The solution is:

[0562] (40)

[0563] When the system is in steady state operation, u el =u elref 、i elL =i elLref , we can get D from formula (40): el is a constant, the electrolytic cell power is constant, and when the bus voltage fluctuates, D el The L based on Buck circuit el , C el2 Parameters, N2, k2 are determined according to the simulation operation, and the power of the electrolyzer when the system is stable before and after the disturbance is obtained; in order to change the electrolyzer power in response to the bus voltage change, D el The value of satisfies the interval [0,1], which controls the opening and closing of the Buck circuit switch;

[0564] By modulating D el The corresponding electrolyzer power is:

[0565] (41)

[0566] (3) Battery control design:

[0567] ①Battery in Buck state:

[0568] Assuming the bus power is the difference between the power source power and the load power, the equation (1) is transformed according to the mathematical model of each unit to obtain:

[0569] (42)

[0570] In order to suppress the bus voltage change, the linear combination of battery power deviation and bus voltage deviation is selected to design the macro variable as:

[0571] (43)

[0572] Among them, u batref is the voltage reference value of the battery, in V; k3 and k4 are positive coefficients; i batLref is the reference value of the inductor current of the Buck-Boost circuit, which is determined by the inductor current i batL The value after low-pass filtering is determined in A; u dcref is the DC bus reference voltage, in V;

[0573] Deriving equation (43) and substituting it into equation (29), we obtain:

[0574] (44)

[0575] Among them, N3 is the time constant of cooperative control of the battery module in Buck state;

[0576] According to equations (26), (42) and (44), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained: bat1 The solution is:

[0577] (45)

[0578] ②Battery in Boost state:

[0579] In Boost mode, the battery is equivalent to a power source, and the expression for bus power balance becomes:

[0580] (46)

[0581] The macro variables of linear combination design are similar to the structure of Buck mode, as follows:

[0582] (47)

[0583] Among them, k5 and k6 are positive coefficients;

[0584] Deriving equation (47) and substituting it into equation (29), we obtain:

[0585] (48)

[0586] Wherein, N4 is the time constant of cooperative control of the battery module in the Boost state;

[0587] According to equations (27), (46) and (48), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained bat1 The solution is:

[0588] (49)

[0589] When the system is running in steady state, i bat =i batref 、u bat =u batref 、u dc =u dcref , fuel cell, and electrolyzer power change is 0, and the battery duty cycle is obtained from equations (45) and (49): , the power of the fuel cell, electrolyzer and battery will not change; from equation (47) and equation (49), we can get D based on the collaborative control theory design bat1 With D el , D fc ’ and u dc There is a coupling relationship, the four influence each other, when u dc When fluctuation occurs, D bat1 , D el and D fc ’ Corresponding changes occur: when the DC bus voltage is higher than the rated value, the power surplus in the microgrid is reduced by increasing the electrolyzer power and the charging power of the battery; on the contrary, when the bus voltage is lower than the rated value, the system power is supplemented by increasing the fuel cell power and the discharging power of the battery.

[0590] Specifically, the control stability verification module implements:

[0591] The control parameters include ~ ;

[0592] In order to verify the stability of the proposed control strategy in the DC microgrid under small disturbances, a small signal model of the microgrid is established;

[0593] The small signal models of the electrolyzer Buck circuit, fuel cell Boost circuit, and battery DC / DC loop are established respectively;

[0594] Considering the photovoltaic and DC loads as constant power units, the small signal model of the DC microgrid is obtained from the DC bus KCL relationship as shown in formula (50):

[0595] (50)

[0596] Among them, the DC microgrid small signal model variables ,in A is a variable including voltage and current; DC is the coefficient matrix;

[0597] The DC microgrid small signal model constructed based on formula (50) is expressed by the coefficient matrix A DC Analyze the characteristic roots of the system; the collaborative control coefficient N is a time constant that determines the speed at which the macro variables converge to the manifold; in the system stability analysis, determine ~ The value range of .

[0598] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the above-mentioned integrated control method of an electric-hydrogen energy hub based on collaborative control theory are implemented.

[0599] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned integrated control method for an electric-hydrogen energy hub based on collaborative control theory.

[0600] It should be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may 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 codes. The solutions in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and interpreted scripting language JavaScript, etc.

[0601] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0602] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0603] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0604] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. 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.

[0605] Obviously, those skilled in the art can 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 coordinated optimization control method for an electric hydrogen energy hub, characterized in that: The steps include: Construct an electric hydrogen energy hub structure that couples photovoltaic power generation units, hydrogen energy units, and battery units to the DC bus, and establish models for each unit; Determine the output of each unit through each unit model, and design the coordinated control strategy of the electric-hydrogen fusion hub based on the coordinated control theory; A small signal model is constructed based on each unit model. The stability of the proposed cooperative control strategy under small disturbances in the DC microgrid is verified through the small signal model, and the optimal values ​​of each control parameter of the cooperative control strategy are determined.

2. The method for coordinated optimization control of an electric hydrogen energy hub according to claim 1, characterized in that: The construction couples the photovoltaic power generation unit, the hydrogen energy unit, and the battery unit to the electric hydrogen energy hub structure of the DC bus, and establishes the model of each unit, including: The structure of the electric-hydrogen energy hub is constructed according to the composition of the electric-hydrogen energy hub and the connection mode between the equipment. Among them, the photovoltaic power generation unit, the hydrogen energy unit and the battery unit are connected to the DC bus through the converter; the hydrogen energy unit includes a fuel cell and an electrolyzer; The voltage dynamic equation of the DC bus capacitor is as follows: （1） Among them, C dc 、u dc are the DC bus capacitance and voltage respectively, in V; P pv , P fc , P el , P bat , P load They are the power from photovoltaics flowing into the DC bus, the power from fuel cells flowing into the DC bus, the power from electrolyzers flowing into the DC bus, the power from batteries flowing into the DC bus, and the power from loads flowing into the DC bus, in W. According to the type and technical characteristics of each unit, the mathematical model of photovoltaic power generation unit, fuel cell, electrolyzer, battery and their connection circuit is established; The photovoltaic power generation unit includes a plurality of photovoltaic cell monomers; For a photovoltaic power generation unit composed of multiple photovoltaic battery cells connected in series and parallel to form photovoltaic power sources of different capacities, the output current of the photovoltaic battery cell is: （2） in: （3） （4） Among them, I p ,I ph ,I p0 ,I sh ,I d They are the output current of the photovoltaic cell, the photocurrent, the reverse saturation current of the diode, the leakage current and the current flowing through the diode, in A; q is the electron charge; U p is the open circuit voltage of the photovoltaic cell, in V; R ss , R sh are the equivalent series resistance and parallel resistance, in Ω; A is the ideal quality factor of the diode; k is the Boltzmann constant; T pv is the temperature of the photovoltaic cell, in K; exp() is an exponential function; The photovoltaic power generation unit is connected through a Boost circuit and uses maximum power point tracking control; The fuel cell uses a PEM fuel cell, and the internal voltage equation corresponding to the PEM fuel cell is: （5） Among them, E fc is the voltage inside the fuel cell; E0 is the standard reference potential under standard conditions, in V; R is the gas constant, with a value of , T fc is the fuel cell temperature, in K; F is the Faraday constant, with a value of 96485C / mol; is the hydrogen partial pressure, in Pa; is the oxygen partial pressure, in pa; E d,fc Delayed effect voltage for fuel and oxidizer; The fuel cell output voltage is: （6） in: （7） （8） （9） Among them, U fc,act , U fc,ohm , U fc,conc and U fc is the polarization voltage, ohmic voltage, concentration voltage, and output voltage of the fuel cell, in V; i fcd is the unit current density of the fuel cell, in A / cm 2 ; a, b are the constants of the Tafel equation, in V / K; R fc,ohm is the resistance of the polymer film, the resistance between the film and the electrode, and the integrated resistance between the electrodes, in Ω; z is the number of participating electrons; i fc,limit is the limiting current density of the fuel cell, in A / cm 2 ; Multiple fuel cells are connected in series and parallel to form a fuel cell stack, and its output power P fc for: （10） in: （11） （12） Among them, u fc is the fuel cell stack voltage, in V; i fc is the fuel cell stack current, in A; N fcs 、N fcp are the number of fuel cells in series and parallel respectively; I fc is the fuel cell current, in A; The fuel cell provides power to the DC bus through the Boost circuit, and the differential equation is established: （13） in: （14） Among them, i fcL is the inductor current in the boost circuit connected to the fuel cell, in A; C fc1 The low-voltage side capacitance of the boost circuit connected to the fuel cell, in F; L fc is the inductance of the boost circuit connected to the fuel cell, in H; D fc is the duty cycle of the boost circuit controller connected to the fuel cell; A PEM electrolyzer is used, which consists of multiple electrolytic chambers connected in series, and multiple groups of electrolytic cells are connected in parallel to a DC power supply; The voltage-current equation of the electrolysis chamber terminal voltage at any temperature is: （15） in: （16） （17） （18） Among them, E el , U el,act , U el,ohm and U el They are the open circuit voltage, polarization overvoltage, ohmic polarization voltage and terminal voltage of the electrolytic cell, in V; α H2O is the water activity between the anode and the electrolyte, here it is 1; T el is the electrolyte temperature, in K; α is the transfer coefficient; i eld is the electrolytic cell current density; i el,0 Electrolytic cell exchange current density; R el,ohm is the membrane resistance; Multiple electrolytic chambers are connected in series and parallel to form an electrolytic cell stack, which consumes power P el for: （19） in: （20） （21） Among them, u el is the electrolysis voltage, in V; i el is the electrolysis current, in A; N els 、N elp are the number of electrolytic cells connected in series and in parallel respectively; I el is the electrolytic cell current, in A; The DC bus provides electrical energy for the electrolyzer to produce hydrogen through the Buck circuit, and the differential equation is established as follows: （22） Among them, i elL is the inductor current in the Buck circuit connected to the electrolytic cell, in A; C el2 The low-voltage side capacitance of the Buck circuit connected to the electrolytic cell, in F; L el is the inductance of the Buck circuit connected to the electrolytic cell, in H; D el is the duty cycle of the Buck circuit controller connected to the electrolyzer; A lead-acid battery is selected as the electrochemical energy storage device, and its terminal voltage is: （23） Among them, the controlled voltage source equation is: （24） Among them, u bat 、E bat 、E bat0 and K bat They are the battery terminal voltage, internal potential, no-load voltage and polarization voltage, in V; Q n is the battery capacity, in Ah; I bat is the battery charge and discharge current, in A; B1 is the voltage change coefficient, in V; B2 is the capacity change coefficient, in ; R eq is the equivalent internal resistance of the battery, in Ω; The battery state of charge S bat The expression for remaining capacity is: （25） Among them, S bat0 is the initial state of charge of the battery, in %; The battery is charged and discharged via a bidirectional Buck-Boost circuit, and the differential equation is established: (1) Buck working status: （26） (2) Boost working status: （27） Among them, i batL is the inductor current in the bidirectional Buck-Boost circuit connected to the battery, in A; C bat2 The low-voltage side capacitor of the bidirectional Buck-Boost circuit connected to the battery, in F; L bat is the inductance of the bidirectional Buck-Boost circuit connected to the battery, in H; D bat1 It is the duty cycle of the high-side switch controller of the bidirectional Buck-Boost circuit connected to the battery.

3. The method for coordinated optimization control of an electric hydrogen energy hub according to claim 1, characterized in that: The output of each unit is determined by each unit model, and the coordinated control strategy of the electric-hydrogen fusion hub is designed based on the coordinated control theory, including: Clarify the basic principles and framework of collaborative control theory, determine the coordination mechanism and information interaction mode between multi-unit models, and analyze the application of collaborative control theory in complex energy systems; Consider the microgrid as an n-dimensional nonlinear system as shown in formula (28): （28） Where x is the system state vector; d is the control input; t is time; f is the function expression of x, d, and t; Cooperative control is based on the derivation of control laws based on the nonlinear system model, including the definition of macro variables and the solution of control quantities. The macro variable Ψ(x) is a function of the state variable in the nonlinear system, and the state variable is selected according to the purpose to be achieved by the control system. Through cooperative control, the macro variable can converge and remain on the manifold Ψ(x)=0. The dynamic equation of the macro variable tending to the manifold after the system disturbance is described as: （29） Where N is a time constant, which determines the convergence speed of the macro variables to the manifold, and N>0; Substituting the constructed macro variables into equation (28) into equation (29) yields: （30） By solving equation (29), we can obtain the solution of d. Under the action of d, the nonlinear system recovers stability from any state after being disturbed, and the macro variables move toward the manifold, gradually approaching the equilibrium point of the system. Solving the ordinary differential equation (28) yields the macro variables: （31） Among them, Ψ(0) is the initial state of the macro variable; According to the principles of collaborative control theory, the coordinated control strategy of the system is designed and constructed, including: (1) Fuel cell control design: The relationship between the input voltage and output voltage in the Boost circuit where the fuel cell is located is: （32） Combined with the differential equation of the Boost circuit, the macro control variables are designed as follows: （33） Among them, u fcref is the input voltage reference value of the Boost circuit, in V; k1 is the positive coefficient; i fcLref is the reference value of the inductor current of the Boost circuit, which is determined by the inductor current i fcL The value after low-pass filtering is determined in A; Derivative (33) and substitute it into (29), we get the dynamic process of macro variable Ψ1 tending to the manifold: （34） Wherein, N1 is the time constant of the coordinated control of the fuel cell module; According to equations (13) and (34), the duty cycle D of the boost circuit controller where the fuel cell is located is obtained: fc ’ The solution is: （35） When the system is in steady state operation, u fc =u fcref 、i fcL =i fcLref , from formula (35) we get D fc ’ is a constant, the fuel cell power is constant, and when the bus voltage fluctuates, D fc ’ The L based on the Boost circuit changes accordingly to achieve fuel cell power response. fc , C fc1 Parameters, N1 and k1 are determined according to the simulation operation, and the power of the fuel cell when the system is stable before and after the disturbance is obtained; To achieve the change of fuel cell power in response to bus voltage changes, D fc ’ The value of satisfies the interval [0,1], which controls the on / off of the Boost circuit switch; By modulating D fc ’ The corresponding fuel cell power is: （36） (2) Electrolyzer control design: The relationship between the input voltage and output voltage in the Buck circuit where the electrolyzer is located is: （37） In order to ensure that the output power of the electrolyzer is equal to the set power, the macro variables are designed in combination with the Buck circuit differential equation as follows: （38） Among them, u elref is the reference value of the Buck circuit output voltage, in V; k2 is a positive coefficient; i elLref is the reference value of the inductor current of the Buck circuit, which is determined by the inductor current i elL The value after low-pass filtering is determined in A; Derivative (38) and substitute it into (29), we get the dynamic process of macro variable Ψ2 tending to the manifold: （39） Wherein, N2 is the time constant of the coordinated control of the electrolyzer modules; According to equations (22) and (39), the duty cycle D of the Buck circuit controller where the electrolyzer is located is obtained el The solution is: （40） When the system is in steady state operation, u el =u elref 、i elL =i elLref , we can get D from formula (40): el is a constant, the electrolytic cell power is constant, and when the bus voltage fluctuates, D el The L based on Buck circuit el , C el2 Parameters, N2, k2 are determined according to the simulation operation, and the power of the electrolyzer when the system is stable before and after the disturbance is obtained; in order to change the electrolyzer power in response to the bus voltage change, D el The value of satisfies the interval [0,1], which controls the opening and closing of the Buck circuit switch; By modulating D el The corresponding electrolyzer power is: （41） (3) Battery control design: ①Battery in Buck state: Assuming the bus power is the difference between the power source power and the load power, the equation (1) is transformed according to the mathematical model of each unit to obtain: （42） In order to suppress the bus voltage change, the linear combination of battery power deviation and bus voltage deviation is selected to design the macro variable as: （43） Among them, u batref is the voltage reference value of the battery, in V; k3 and k4 are positive coefficients; i batLref is the reference value of the inductor current of the Buck-Boost circuit, which is determined by the inductor current i batL The value after low-pass filtering is determined in A; u dcref is the DC bus reference voltage, in V; Deriving equation (43) and substituting it into equation (29), we obtain: （44） Among them, N3 is the time constant of cooperative control of the battery module in Buck state; According to equations (26), (42) and (44), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained: bat1 The solution is: （45） ②Battery in Boost state: In Boost mode, the battery is equivalent to a power source, and the expression for bus power balance becomes: （46） The macro variables of linear combination design are similar to the structure of Buck mode, as follows: （47） Among them, k5 and k6 are positive coefficients; Deriving equation (47) and substituting it into equation (29), we obtain: （48） Wherein, N4 is the time constant of cooperative control of the battery module in the Boost state; According to equations (27), (46) and (48), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained bat1 The solution is: （49） When the system is running in steady state, i bat =i batref 、u bat =u batref 、u dc =u dcref , fuel cell, and electrolyzer power change is 0, and the battery duty cycle is obtained from equations (45) and (49): , the power of the fuel cell, electrolyzer and battery will not change; from equation (47) and equation (49), we can get D based on the collaborative control theory design bat1 With D el , D fc ’ and u dc There is a coupling relationship, the four influence each other, when u dc When fluctuation occurs, D bat1 , D el and D fc ’ Corresponding changes occur: when the DC bus voltage is higher than the rated value, the power surplus in the microgrid is reduced by increasing the electrolyzer power and the charging power of the battery; on the contrary, when the bus voltage is lower than the rated value, the system power is supplemented by increasing the fuel cell power and the discharging power of the battery.

4. The method for coordinated optimization control of an electric hydrogen energy hub according to claim 3 is characterized in that: The small signal model is constructed based on each unit model, and the stability of the proposed coordinated control strategy under the condition of small disturbance of the DC microgrid is verified by the small signal model, and the optimal value of each control parameter of the coordinated control strategy is determined, including: The control parameters include ~ ; In order to verify the stability of the proposed control strategy in the DC microgrid under small disturbances, a small signal model of the microgrid is established; The small signal models of the electrolyzer Buck circuit, fuel cell Boost circuit, and battery DC / DC loop are established respectively; Considering the photovoltaic and DC loads as constant power units, the small signal model of the DC microgrid is obtained from the DC bus KCL relationship as shown in formula (50): （50） Among them, the DC microgrid small signal model variables ,in A is a variable including voltage and current; DC is the coefficient matrix; The DC microgrid small signal model constructed based on formula (50) is expressed by the coefficient matrix A DC Analyze the characteristic roots of the system; the collaborative control coefficient N is a time constant that determines the speed at which the macro variables converge to the manifold; in the system stability analysis, determine ~ The value range of .

5. A coordinated optimization control system for an electric hydrogen energy hub, characterized in that: Includes the following modules: The equipment power calculation module builds an electric hydrogen energy hub structure that couples the photovoltaic power generation unit, hydrogen energy unit, and battery unit to the DC bus, and establishes models for each unit; Integrated control module, which determines the output of each unit through each unit model, and designs the coordinated control strategy of the electric-hydrogen fusion hub based on the coordinated control theory; The control stability verification module builds a small signal model based on each unit model, verifies the stability of the proposed collaborative control strategy under small disturbances of the DC microgrid through the small signal model, and determines the optimal values ​​of each control parameter of the collaborative control strategy.

6. The electric hydrogen energy hub collaborative optimization control system according to claim 5 is characterized in that: The device power calculation module implements: The structure of the electric-hydrogen energy hub is constructed according to the composition of the electric-hydrogen energy hub and the connection between the equipment, in which the photovoltaic power generation unit, the hydrogen energy unit and the battery are connected to the DC bus through the converter; The hydrogen energy unit includes a fuel cell and an electrolyzer; The voltage dynamic equation of the DC bus capacitor is as follows: （1） Among them, C dc 、u dc are the DC bus capacitance and voltage respectively, in V; P pv , P fc , P el , P bat , P load They are the power from photovoltaics flowing into the DC bus, the power from fuel cells flowing into the DC bus, the power from electrolyzers flowing into the DC bus, the power from batteries flowing into the DC bus, and the power from loads flowing into the DC bus, in W. According to the type and technical characteristics of each unit, the mathematical model of photovoltaic power generation unit, fuel cell, electrolyzer, battery and their connection circuit is established; The photovoltaic power generation unit includes multiple photovoltaic battery cells, which are connected in series and parallel to form photovoltaic power sources of different capacities. The output current of the photovoltaic battery is: （2） in: （3） （4） Among them, I p ,I ph ,I p0 ,I sh ,I d They are the output current of the photovoltaic cell, the photocurrent, the reverse saturation current of the diode, the leakage current and the current flowing through the diode, in A; q is the electron charge, which is taken as ; U p is the open circuit voltage of the photovoltaic cell, in V; R ss , R sh are the equivalent series resistance and parallel resistance, in Ω; A is the ideal quality factor of the diode; k is the Boltzmann constant, which is ; T pv is the temperature of the photovoltaic cell, in K; exp() is an exponential function; The photovoltaic power generation unit is connected through a Boost circuit and uses maximum power point tracking control; The fuel cell uses a PEM fuel cell, and the internal voltage equation corresponding to the PEM fuel cell is: （5） Among them, E fc is the voltage inside the fuel cell; E0 is the standard reference potential under standard conditions, in V; R is the gas constant, with a value of 8.3143 J / ( ), T fc is the fuel cell temperature, in K; F is the Faraday constant; is the hydrogen partial pressure, in Pa; is the oxygen partial pressure, in pa; E d,fc Delayed effect voltage for fuel and oxidizer; The fuel cell output voltage is: （6） in: （7） （8） （9） Among them, U fc,act , U fc,ohm , U fc,conc and U fc is the polarization voltage, ohmic voltage, concentration voltage, and output voltage of the fuel cell, in V; i fcd is the unit current density of the fuel cell, in A / cm 2 ; a, b are the constants of the Tafel equation, in V / K; R fc,ohm is the resistance of the polymer film, the resistance between the film and the electrode, and the integrated resistance between the electrodes, in Ω; z is the number of participating electrons; i fc,limit is the limiting current density of the fuel cell, in A / cm 2 ; Multiple fuel cells are connected in series and parallel to form a fuel cell stack, and its output power P fc for: （10） in: （11） （12） Among them, u fc is the fuel cell stack voltage, in V; i fc is the fuel cell stack current, in A; N fcs 、N fcp are the number of fuel cells in series and parallel respectively; I fc is the fuel cell current, in A; The fuel cell provides power to the DC bus through the Boost circuit, and the differential equation is established: （13） in: （14） Among them, i fcL is the inductor current in the boost circuit connected to the fuel cell, in A; C fc1 The low-voltage side capacitance of the boost circuit connected to the fuel cell, in F; L fc is the inductance of the boost circuit connected to the fuel cell, in H; D fc is the duty cycle of the boost circuit controller connected to the fuel cell; A PEM electrolyzer is used, which consists of multiple electrolytic chambers connected in series, and multiple groups of electrolytic cells are connected in parallel to a DC power supply; The voltage-current equation of the electrolysis chamber terminal voltage at any temperature is: （15） in: （16） （17） （18） Among them, E el , U el,act , U el,ohm and U el They are the open circuit voltage, polarization overvoltage, ohmic polarization voltage and terminal voltage of the electrolytic cell, in V; α H2O is the water activity between the anode and the electrolyte, here it is 1; T el is the electrolyte temperature, in K; α is the transfer coefficient; i eld is the electrolytic cell current density; i el,0 Electrolytic cell exchange current density; R el,ohm is the membrane resistance; Multiple electrolytic chambers are connected in series and parallel to form an electrolytic cell stack, which consumes power P el for: （19） in: （20） （21） Among them, u el is the electrolysis voltage, in V; i el is the electrolysis current, in A; N els 、N elp are the number of electrolytic cells connected in series and in parallel respectively; I el is the electrolytic cell current, in A; The DC bus provides electrical energy for the electrolyzer to produce hydrogen through the Buck circuit, and the differential equation is established as follows: （22） Among them, i elL is the inductor current in the Buck circuit connected to the electrolytic cell, in A; C el2 The low-voltage side capacitance of the Buck circuit connected to the electrolytic cell, in F; L el is the inductance of the Buck circuit connected to the electrolytic cell, in H; D el is the duty cycle of the Buck circuit controller connected to the electrolyzer; A lead-acid battery is selected as the electrochemical energy storage device, and its terminal voltage is: （23） Among them, the controlled voltage source equation is: （24） Among them, u bat 、E bat 、E bat0 and K bat They are the battery terminal voltage, internal potential, no-load voltage and polarization voltage, in V; Q n is the battery capacity, in Ah; I bat is the battery charge and discharge current, in A; B1 is the voltage change coefficient, in V; B2 is the capacity change coefficient, in ; R eq is the equivalent internal resistance of the battery, in Ω; The battery state of charge S bat The expression for remaining capacity is: （25） Among them, S bat0 is the initial state of charge of the battery, in %; The battery is charged and discharged via a bidirectional Buck-Boost circuit, and the differential equation is established: (1) Buck working status: （26） (2) Boost working status: （27） Among them, i batL is the inductor current in the bidirectional Buck-Boost circuit connected to the battery, in A; C bat2 The low-voltage side capacitor of the bidirectional Buck-Boost circuit connected to the battery, in F; L bat is the inductance of the bidirectional Buck-Boost circuit connected to the battery, in H; D bat1 It is the duty cycle of the high-side switch controller of the bidirectional Buck-Boost circuit connected to the battery.

7. The electric hydrogen energy hub collaborative optimization control system according to claim 5 is characterized in that: The integrated control module realizes: Clarify the basic principles and framework of collaborative control theory, determine the coordination mechanism and information interaction mode between multi-unit models, and analyze the application of collaborative control theory in complex energy systems; Consider the microgrid as an n-dimensional nonlinear system as shown in formula (28): （28） Where x is the system state vector; d is the control input; t is time; f is the function expression of x, d, and t; Cooperative control is based on the derivation of control laws based on the nonlinear system model, including the definition of macro variables and the solution of control quantities. The macro variable Ψ(x) is a function of the state variable in the nonlinear system, and the state variable is selected according to the purpose to be achieved by the control system. Through cooperative control, the macro variable can converge and remain on the manifold Ψ(x)=0. The dynamic equation of the macro variable tending to the manifold after the system disturbance is described as: （29） Where N is a time constant, which determines the convergence speed of the macro variables to the manifold, and N>0; Substituting the constructed macro variables into equation (28) into equation (29) yields: （30） By solving equation (29), we can obtain the solution of d. Under the action of d, the nonlinear system recovers stability from any state after being disturbed, and the macro variables move toward the manifold, gradually approaching the equilibrium point of the system. Solving the ordinary differential equation (28) yields the macro variables: （31） Among them, Ψ(0) is the initial state of the macro variable; According to the principles of collaborative control theory, the coordinated control strategy of the system is designed and constructed, including: (1) Fuel cell control design: The relationship between the input voltage and output voltage in the Boost circuit where the fuel cell is located is: （32） Combined with the differential equation of the Boost circuit, the macro control variables are designed as follows: （33） Among them, u fcref is the input voltage reference value of the Boost circuit, in V; k1 is the positive coefficient; i fcLref is the reference value of the inductor current of the Boost circuit, which is determined by the inductor current i fcL The value after low-pass filtering is determined in A; Derivative (33) and substitute it into (29), we get the dynamic process of macro variable Ψ1 tending to the manifold: （34） Wherein, N1 is the time constant of the coordinated control of the fuel cell module; According to equations (13) and (34), the duty cycle D of the boost circuit controller where the fuel cell is located is obtained: fc ’ The solution is: （35） When the system is in steady state operation, u fc =u fcref 、i fcL =i fcLref , from formula (35) we get D fc ’ is a constant, the fuel cell power is constant, and when the bus voltage fluctuates, D fc ’ The L based on the Boost circuit changes accordingly to achieve fuel cell power response. fc , C fc1 Parameters, N1 and k1 are determined according to the simulation operation, and the power of the fuel cell when the system is stable before and after the disturbance is obtained; To achieve the change of fuel cell power in response to bus voltage changes, D fc ’ The value of satisfies the interval [0,1], which controls the on / off of the Boost circuit switch; By modulating D fc ’ The corresponding fuel cell power is: （36） (2) Electrolyzer control design: The relationship between the input voltage and output voltage in the Buck circuit where the electrolyzer is located is: （37） In order to ensure that the output power of the electrolyzer is equal to the set power, the macro variables are designed in combination with the Buck circuit differential equation as follows: （38） Among them, u elref is the reference value of the Buck circuit output voltage, in V; k2 is a positive coefficient; i elLref is the reference value of the inductor current of the Buck circuit, which is determined by the inductor current i elL The value after low-pass filtering is determined in A; Derivative (38) and substitute it into (29), we get the dynamic process of macro variable Ψ2 tending to the manifold: （39） Wherein, N2 is the time constant of the coordinated control of the electrolyzer modules; According to equations (22) and (39), the duty cycle D of the Buck circuit controller where the electrolyzer is located is obtained el The solution is: （40） When the system is in steady state operation, u el =u elref 、i elL =i elLref , we can get D from formula (40): el is a constant, the electrolytic cell power is constant, and when the bus voltage fluctuates, D el The L based on Buck circuit el , C el2 Parameters, N2, k2 are determined according to the simulation operation, and the power of the electrolyzer when the system is stable before and after the disturbance is obtained; in order to change the electrolyzer power in response to the bus voltage change, D el The value of satisfies the interval [0,1], which controls the opening and closing of the Buck circuit switch; By modulating D el The corresponding electrolyzer power is: （41） (3) Battery control design: ①Battery in Buck state: Assuming the bus power is the difference between the power source power and the load power, the equation (1) is transformed according to the mathematical model of each unit to obtain: （42） In order to suppress the bus voltage change, the linear combination of battery power deviation and bus voltage deviation is selected to design the macro variable as: （43） Among them, u batref is the voltage reference value of the battery, in V; k3 and k4 are positive coefficients; i batLref is the reference value of the inductor current of the Buck-Boost circuit, which is determined by the inductor current i batL The value after low-pass filtering is determined in A; u dcref is the DC bus reference voltage, in V; Deriving equation (43) and substituting it into equation (29), we obtain: （44） Among them, N3 is the time constant of cooperative control of the battery module in Buck state; According to equations (26), (42) and (44), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained: bat1 The solution is: （45） ②Battery in Boost state: In Boost mode, the battery is equivalent to a power source, and the expression for bus power balance becomes: （46） The macro variables of linear combination design are similar to the structure of Buck mode, as follows: （47） Among them, k5 and k6 are positive coefficients; Deriving equation (47) and substituting it into equation (29), we obtain: （48） Wherein, N4 is the time constant of cooperative control of the battery module in the Boost state; According to equations (27), (46) and (48), the duty cycle D of the Buck-Boost circuit controller where the battery is located is obtained bat1 The solution is: （49） When the system is running in steady state, i bat =i batref 、u bat =u batref 、u dc =u dcref , fuel cell, and electrolyzer power change is 0, and the battery duty cycle is obtained from equations (45) and (49): , the power of the fuel cell, electrolyzer and battery will not change; from equation (47) and equation (49), we can get D based on the collaborative control theory design bat1 With D el , D fc ’ and u dc There is a coupling relationship, the four influence each other, when u dc When fluctuation occurs, D bat1 , D el and D fc ’ Corresponding changes occur: when the DC bus voltage is higher than the rated value, the power surplus in the microgrid is reduced by increasing the electrolyzer power and the charging power of the battery; on the contrary, when the bus voltage is lower than the rated value, the system power is supplemented by increasing the fuel cell power and the discharging power of the battery.

8. The electric hydrogen energy hub collaborative optimization control system according to claim 5 is characterized in that: The control stability test module realizes: The control parameters include ~ ; In order to verify the stability of the proposed control strategy in the DC microgrid under small disturbances, a small signal model of the microgrid is established; The small signal models of the electrolyzer Buck circuit, fuel cell Boost circuit, and battery DC / DC loop are established respectively; Considering the photovoltaic and DC loads as constant power units, the small signal model of the DC microgrid is obtained from the DC bus KCL relationship as shown in formula (50): （50） Among them, the DC microgrid small signal model variables ,in A is a variable including voltage and current; DC is the coefficient matrix; The DC microgrid small signal model constructed based on formula (50) is expressed by the coefficient matrix A DC Analyze the characteristic roots of the system; the collaborative control coefficient N is a time constant that determines the speed at which the macro variables converge to the manifold; in the system stability analysis, determine ~ The value range of .

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of a coordinated optimization control method for an electric-hydrogen energy hub are implemented as described in any one of claims 1 to 4.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a coordinated optimization control method for an electric-hydrogen energy hub are implemented as described in any one of claims 1 to 4.

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