SOFC-GT system integrated power generation modeling and cooperative control method for micro-grid application

Abstract

The invention discloses a micro-grid application-oriented SOFC-GT system integrated power generation modeling and cooperative control method, relates to the technical field of new energy power generation, and is used for solving the technical problems that an existing solid oxide fuel cell is slow in dynamic response to power requirements and low in power generation efficiency. The SOFC-GT system integrated power generation modeling method for micro-grid application comprises the following steps: determining an SOFC power generation model and a GT power generation model; dynamic description of tail gas output is added on the basis of the SOFC power generation model; on the basis of the GT power generation model, dynamic description of bypass SOFC tail gas fuel input is introduced, and then an SOFC-GT system integrated power generation dynamic model is obtained; the cooperative control method comprises the following steps: respectively constructing a basic controller of the SOFC power generation unit and a basic controller of the GT power generation unit; and a top-layer adaptive power distribution strategy is constructed to realize integrated power generation. The technical scheme of the invention provides an SOFC-GT system integrated power generation modeling and cooperative control method for micro-grid application.

Description

Technical Field

[0001] The present invention relates to the field of renewable energy power generation technology, and in particular to an integrated power generation modeling and coordinated control method of a SOFC-GT system for microgrid applications. Background Art

[0002] Energy is the cornerstone of human survival and development and the lifeblood of the national economy. At present, my country's energy supply structure is still dominated by traditional fossil energy power generation, and electricity supply is achieved through centralized large power grids, which have the disadvantages of high energy consumption, heavy pollution, unsustainability and poor reliability.

[0003] Compared with photovoltaic, wind power and other renewable energy generation devices currently used in power grids on a large scale, Solid Oxide Fuel Cell (SOFC) has a broader development prospect. Its power generation process is continuous, stable and controllable, and is not affected by factors such as geographical location and meteorological conditions. However, compared with other energy storage power devices such as supercapacitors or lithium-ion batteries, SOFC's dynamic response to power requirements is relatively slow, limiting it to operate only in Grid Following (GFL) mode, and it is difficult to operate in Grid Forming (GFM) mode. In addition, during the operation of solid oxide fuel cells, a large amount of unreacted fuel and the accompanying heat will be discharged as exhaust gas, which limits its power generation efficiency to a certain extent and causes waste of resources. Summary of the invention

[0004] The purpose of the present invention is to provide an integrated power generation modeling and coordinated control method of a SOFC-GT system for microgrid applications, which is used to solve the technical problems of slow dynamic response of existing solid oxide fuel cells to power requirements and low power generation efficiency. In view of this, the present invention is implemented through the following scheme.

[0005] In a first aspect, the present invention provides a SOFC-GT system integrated power generation modeling method for microgrid applications, comprising:

[0006] Determine the SOFC power generation model and GT power generation model;

[0007] Based on the SOFC power generation model, a dynamic description of its tail gas output is added;

[0008] Based on the GT power generation model, a dynamic description of bypass SOFC tail gas fuel input is introduced to obtain a SOFC-GT system integrated power generation dynamic model;

[0009] Here, SOFC stands for solid oxide fuel cell, and GT stands for gas turbine.

[0010] Compared with the prior art, in the SOFC-GT system integrated power generation modeling method for microgrid applications of the present invention, by introducing the dynamic description of bypass SOFC tail gas fuel input on the basis of the GT power generation model, the gas turbine and the solid oxide fuel cell are coupled to obtain the SOFC-GT system integrated power generation dynamic model. Based on the SOFC-GT system integrated power generation dynamic model, it is possible to fully utilize the exhaust gas discharged by the solid oxide fuel cell for secondary power generation, and effectively improve the power generation efficiency compared to a single solid oxide fuel cell. At the same time, the natural mechanical inertia of the gas turbine can help the SOFC-GT system to achieve grid / island mode operation. The SOFC-GT system is crucial to improving the overall power generation efficiency of the system, enhancing the elasticity and flexibility of the power grid, and ultimately ensuring the safe, reliable and economical operation of the power grid. Through the above-mentioned technical solution of the present invention, the technical problems of the slow dynamic response of the existing solid oxide fuel cell to the power requirements and the low power generation efficiency are solved.

[0011] Furthermore, in the SOFC-GT system integrated power generation modeling and coordinated control method for microgrid application of the present invention, the input of the SOFC power generation model is the output current and the original fuel molar flow rate of the SOFC stack at the last moment;

[0012] The output of the SOFC power generation model is the SOFC stack voltage and the molar flow rate of the tail gas;

[0013] and / or,

[0014] The input of the GT power generation model is the fuel supply control amount, the electromagnetic power output of the generator at the last moment, and the rotor speed;

[0015] The output of the GT power generation model is three-phase alternating current.

[0016] Furthermore, in the SOFC-GT system integrated power generation modeling and coordinated control method for microgrid application of the present invention, the SOFC power generation model outputs the SOFC stack voltage, including:

[0017] The original fuel molar flow is converted into hydrogen molar flow after the fuel processing step;

[0018] Obtain the gas partial pressure and obtain the Nernst voltage of SOFC through the Nernst voltage equation;

[0019] Convert numerical quantities into electrical quantities through controllable voltage source modules within engineering design or simulation software;

[0020] The ohmic polarization of the cell stack and the wires is simulated by equivalently simulating the ohmic polarization of the cell stack by series resistance, and then the SOFC cell stack voltage is outputted by the SOFC power generation model;

[0021] and / or,

[0022] The GT power generation model outputs three-phase alternating current, including:

[0023] The fuel supply control quantity is obtained by passing through the valve and the fuel system link to obtain the fuel flow supplied by the fuel system;

[0024] After being combined with the bypass SOFC tail gas fuel and then passing through the catalytic combustion delay link, the actual fuel input to the gas turbine is obtained, and the input mechanical torque of the gas turbine is obtained;

[0025] The speed of the gas turbine at the next moment is obtained by the difference between the mechanical torque of the gas turbine and the output electromagnetic torque through the rotor link, and is converted into three-phase alternating current and output through the synchronous generator module of the engineering design or simulation software.

[0026] In a second aspect, the present invention provides a SOFC-GT system integrated power generation coordinated control method, which is used to control the SOFC-GT system integrated power generation dynamic model obtained by the above-mentioned SOFC-GT system integrated power generation modeling method for microgrid application, and the SOFC-GT system integrated power generation coordinated control method comprises:

[0027] The basic controller of SOFC power generation unit and the basic controller of GT power generation unit are constructed respectively; then the top-level adaptive power allocation strategy is constructed to realize integrated power generation; among which:

[0028] The basic controller of the SOFC power generation unit includes control of fuel input flow, DC bus voltage, and current-source inverter power output;

[0029] The GT power generation unit basic controller includes GT output power and speed control considering bypass SOFC tail gas input;

[0030] The top-level adaptive power allocation strategy determines the respective power output reference values ​​by acquiring the current operating status of each power generation unit, and finally realizes the integrated power generation of the system.

[0031] Furthermore, in the SOFC-GT system integrated power generation coordinated control method of the present invention, the construction of the SOFC power generation unit basic controller includes:

[0032] Obtain the hydrogen molar flow rate and output current of the SOFC stack, and obtain the fuel utilization rate;

[0033] Determining a fuel utilization rate target value, and controlling the original fuel molar flow rate so that the fuel utilization rate is maintained near the fuel utilization rate target value;

[0034] Obtaining the SOFC stack voltage and the internal inductor current of the Boost converter, determining a voltage target value, and controlling the DC bus voltage to be stable near the voltage target value;

[0035] Obtain the inductor voltage and inductor current on the grid side, obtain the active power and reactive power output by the SOFC power generation unit, and obtain the three-phase electrical frequency and phase angle of the grid through a phase-locked loop;

[0036] Obtain the voltage of the line capacitor and the current flowing through the inductor on the power supply side;

[0037] An output power controller for grid-following operation is designed for the inverter to control the active power and reactive power output by the SOFC power generation unit in the grid-following mode.

[0038] Furthermore, in the SOFC-GT system integrated power generation coordinated control method of the present invention, the GT power generation unit basic controller is constructed, including:

[0039] A speed governor is designed for the GT power generation unit, and the speed governor can be switched between a grid-following mode and a grid-building mode according to the SOFC-GT system, so as to stably control the speed of the gas turbine;

[0040] Wherein, in the grid-following mode, the speed governor has synchronization, and the speed governor can adjust the output power and rotor speed of the gas turbine without steady-state error. The relationship between the output power and the rotor speed is:

[0041] ;

[0042] in:

[0043] ;

[0044] ;

[0045] In the above formula, To control the amount of fuel supply, is the additional fuel compensation amount, is the scaling factor, is the gas turbine rotor speed, is the speed regulator time constant, is the Lagrangian operator, The fuel supply control quantity for the power stage, The fuel supply control quantity for the speed link, is the reference power output of the gas turbine, is the gas turbine output power, is the proportional link control gain, is the control gain of the first integral link, is the control gain of the second integral link, is the control gain of the third integral link, is the reference speed of the gas turbine rotor, is the droop coefficient;

[0046] In the grid-building mode, when the speed regulator controls the frequency of the SOFC-GT system to maintain the rated frequency, the output power automatically tracks the actual load power demand, and the relationship between the rotor speed and the fuel supply control amount is:

[0047] ;

[0048] in, To control the amount of fuel supply, is the additional fuel compensation amount, is the scaling factor, is the gas turbine rotor speed, is the speed regulator time constant, is a pull operator, Provides control quantity of fuel supply for speed link;

[0049] Among them, the basic controller of the GT power generation unit is a gas turbine fuel controller designed to consider the bypass SOFC tail gas fuel input; the gas turbine fuel controller takes the rotor speed of the gas turbine at the previous moment and the electromagnetic power output of the generator as input.

[0050] Furthermore, in the SOFC-GT system integrated power generation coordinated control method of the present invention, in the process of designing a gas turbine fuel controller that considers bypassing the SOFC tail gas fuel input:

[0051] Ensure that the fuel supply is greater than or equal to the minimum warning value of fuel input;

[0052] Regarding the supply amount of the fuel, in addition to the bypass input of the SOFC tail gas fuel, it is also necessary to directly provide additional fuel compensation to the gas turbine from the original fuel system;

[0053] For the fuel compensation, the following equation must be satisfied:

[0054] ;

[0055] in, is the additional fuel compensation amount, is the minimum warning value of fuel input, is the molar flow rate of exhaust fuel.

[0056] Furthermore, in the SOFC-GT system integrated power generation coordinated control method of the present invention, the control process of the basic controller of the GT power generation unit is:

[0057] When the SOFC-GT system is in the grid-following mode, the power loop control switch is in a closed state;

[0058] When the SOFC-GT system is in the grid-building mode, the power ring control switch is in an open state.

[0059] Furthermore, in the SOFC-GT system integrated power generation coordinated control method of the present invention, the construction of the top-level adaptive power allocation strategy includes:

[0060] Obtaining hydrogen molar flow rate, output voltage and tail gas fuel molar flow rate of the SOFC stack;

[0061] Design top-level online adaptive power allocation strategy;

[0062] Among them, the top-level online adaptive power allocation strategy uses the exhaust fuel molar flow rate as a reference to set the target power generation value of each power generation unit after the system is in steady state, and the dynamic process before steady state is dynamically adaptively adjusted according to the current operating status of each power generation unit.

[0063] Furthermore, in the SOFC-GT system integrated power generation coordinated control method of the present invention, in the process of constructing the top-level adaptive power allocation strategy, the output power that the gas turbine should generate when supplied by the tail gas of the solid oxide fuel cell is:

[0064] ;

[0065] in, is the output power of the gas turbine, is the rated output power of the gas turbine, is the exhaust fuel molar flow rate, It is the minimum warning value of fuel input;

[0066] When the SOFC-GT system is in dynamic operation, the unsatisfied output power of the SOFC power generation unit will be borne entirely by the GT power generation module. When the system enters the steady-state operation stage, the target output power of the gas turbine is determined by the SOFC fuel tail gas flow rate.

[0067] The SOFC-GT system can quickly and accurately meet the total power demand;

[0068] As the total power demand changes, the fuel utilization of the solid oxide fuel cell is 0.7~0.9pu, and the overall fuel utilization of the system reaches 1p.u., and all fuel is fully utilized. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0070] Figure 1 A schematic diagram of the working process of the SOFC-GT system of the present invention;

[0071] Figure 2 It is a schematic diagram of the principle of the integrated power generation dynamic model of the SOFC-GT system of the present invention;

[0072] Figure 3 It is a schematic diagram of the principle of the collaborative control method of the present invention;

[0073] Figure 4 It is a schematic diagram of the power output dynamic response of the SOFC-GT system of the present invention in different modes;

[0074] Figure 5 It is a schematic diagram of the dynamic response of the parameters of the SOFC-GT system of the present invention in different modes;

[0075] Figure 6 It is a schematic diagram of the AC bus voltage waveform when the operation mode of the SOFC-GT system of the present invention is switched. DETAILED DESCRIPTION

[0076] In order to make the technical problems, technical solutions and beneficial effects to be solved by 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.

[0077] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0078] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0079] Compared with photovoltaic, wind power and other renewable energy generation devices currently used in power grids on a large scale, Solid Oxide Fuel Cell (SOFC) has a broader development prospect. Its power generation process is continuous, stable and controllable, and is not affected by factors such as geographical location and meteorological conditions. However, compared with other energy storage power devices such as supercapacitors or lithium-ion batteries, SOFC's dynamic response to power requirements is relatively slow, limiting it to operate only in the Grid Following (GFL) mode, and it is difficult to achieve grid forming / islanding (GFM) operation. In addition, during the operation of SOFC, a large amount of unreacted fuel and the accompanying heat will be discharged as exhaust gas, which to a certain extent limits its upper limit of power generation efficiency and causes waste of resources.

[0080] In order to solve the above technical problems, in a first aspect, the present invention provides an integrated power generation modeling method of a SOFC-GT system for microgrid application, comprising:

[0081] Determine the SOFC power generation model and GT power generation model;

[0082] Based on the SOFC power generation model, a dynamic description of its tail gas output is added;

[0083] Based on the GT power generation model, a dynamic description of bypass SOFC tail gas fuel input is introduced to obtain a SOFC-GT system integrated power generation dynamic model;

[0084] Here, SOFC stands for solid oxide fuel cell, and GT stands for gas turbine.

[0085] Under the condition of adopting the above technical scheme, in the SOFC-GT system integrated power generation modeling method for microgrid application of the present invention, by introducing the dynamic description of bypass SOFC tail gas fuel input on the basis of GT power generation model, the gas turbine and solid oxide fuel cell are coupled to obtain the SOFC-GT system integrated power generation dynamic model. Based on the SOFC-GT system integrated power generation dynamic model, it is possible to fully utilize the tail gas discharged by the solid oxide fuel cell for secondary power generation, and effectively improve the power generation efficiency compared with a single solid oxide fuel cell. At the same time, the natural mechanical inertia of the gas turbine can help the SOFC-GT system to realize the grid / island mode operation. The SOFC-GT system is crucial to improving the overall power generation efficiency of the system, enhancing the elasticity and flexibility of the power grid, and ultimately ensuring the safe, reliable and economical operation of the power grid. Through the above technical scheme of the present invention, the technical problems of the slow dynamic response of the existing solid oxide fuel cell to the power requirements and the low power generation efficiency are solved.

[0086] In a second aspect, the present invention provides a SOFC-GT system integrated power generation coordinated control method, which is used to control the SOFC-GT system integrated power generation dynamic model obtained by the above-mentioned SOFC-GT system integrated power generation modeling method for microgrid application, and the SOFC-GT system integrated power generation coordinated control method comprises:

[0087] The basic controller of SOFC power generation unit and the basic controller of GT power generation unit are constructed respectively; then the top-level adaptive power allocation strategy is constructed to realize integrated power generation; among which:

[0088] The basic controller of the SOFC power generation unit includes control of fuel input flow, DC bus voltage, and current-source inverter power output;

[0089] The GT power generation unit basic controller includes GT output power and speed control considering bypass SOFC tail gas input;

[0090] The top-level adaptive power allocation strategy determines the respective power output reference values ​​by acquiring the current operating status of each power generation unit, and finally realizes the integrated power generation of the system.

[0091] When the above technical scheme is adopted, in the integrated power generation coordinated control method of the SOFC-GT system of the present invention, integrated power generation can be achieved by respectively constructing the basic controller of the SOFC power generation unit and the basic controller of the GT power generation unit, and then constructing the top-level adaptive power allocation strategy, and the coordinated operation of the SOFC / GT power generation units inside the system can be realized. Under the premise of ensuring the safe operation of each unit, the system's fast and efficient integrated power generation is achieved, and the system is given the ability to follow the grid and build the grid to meet the flexible operation needs of the microgrid; compared with SOFC single power generation, the integrated power generation system promoted by the present technical scheme can effectively improve the power response speed, and the fuel utilization rate can reach 100%. At the same time, sufficient mechanical inertia is injected into the microgrid, which is of great significance for improving the elasticity and flexibility of the microgrid, promoting the full and efficient utilization of hydrogen-rich fuels, and reducing carbon emissions.

[0092] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific embodiments, but the content of the present invention is not limited to the following embodiments.

[0093] Unless otherwise specified, the raw materials used in the following examples are commercially available.

[0094] Example 1

[0095] This embodiment provides a SOFC-GT system integrated power generation modeling method for microgrid applications, including:

[0096] S100, determining a SOFC power generation model and a GT power generation model;

[0097] S200, adding a dynamic description of the tail gas output thereof based on the SOFC power generation model;

[0098] S300, introducing a dynamic description of bypass SOFC tail gas fuel input on the basis of the GT power generation model, thereby obtaining a SOFC-GT system integrated power generation dynamic model;

[0099] Here, SOFC stands for solid oxide fuel cell, and GT stands for gas turbine.

[0100] This embodiment further provides a SOFC-GT system integrated power generation coordinated control method, which is used to control the SOFC-GT system integrated power generation dynamic model obtained by the above-mentioned SOFC-GT system integrated power generation modeling method for microgrid application, and the SOFC-GT system integrated power generation coordinated control method includes:

[0101] Step 1, constructing a basic controller of a SOFC power generation unit and a basic controller of a GT power generation unit respectively;

[0102] Step 2, then construct a top-level adaptive power allocation strategy to achieve integrated power generation;

[0103] Wherein, the basic controller of the SOFC power generation unit includes control of the fuel input flow, DC bus voltage, and current source inverter power output;

[0104] The GT power generation unit basic controller includes GT output power and speed control considering bypass SOFC tail gas input;

[0105] The top-level adaptive power allocation strategy determines the respective power output reference values ​​by acquiring the current operating status of each power generation unit, and finally realizes the integrated power generation of the system.

[0106] Example 2

[0107] This embodiment provides a SOFC-GT system integrated power generation modeling method for microgrid applications, including:

[0108] S100, determining a SOFC power generation model and a GT power generation model;

[0109] The input of the SOFC power generation model is the output current of the SOFC stack at the last moment and the original fuel molar flow rate, and the output of the SOFC power generation model is the SOFC stack voltage and the molar flow rate of the tail gas; the input of the GT power generation model is the fuel supply control amount, the electromagnetic power output of the generator at the last moment and the rotor speed, and the output of the GT power generation model is three-phase alternating current;

[0110] The SOFC power generation model outputting the SOFC stack voltage may further include:

[0111] S111, the original fuel molar flow is converted into hydrogen molar flow after the fuel processing step;

[0112] S112, obtaining the gas partial pressure, and obtaining the Nernst voltage of the SOFC through the Nernst voltage equation;

[0113] S113, converting the numerical value into an electrical value through a controllable voltage source module within the engineering design or simulation software;

[0114] S114, simulating the ohmic polarization of the inside of the stack and the wires by equivalently connecting the series resistors, and then outputting the SOFC stack voltage through the SOFC power generation model;

[0115] The GT power generation model outputs three-phase alternating current, and may further include:

[0116] S121, the fuel supply control amount is passed through the valve and the fuel system link to obtain the fuel flow supplied by the fuel system;

[0117] S122, after being combined with the bypass SOFC tail gas fuel and then passing through the catalytic combustion delay link, the actual fuel input amount input to the gas turbine is obtained, and the input mechanical torque of the gas turbine is obtained;

[0118] S123, obtaining the speed of the gas turbine at the next moment through the difference between the mechanical torque of the gas turbine and the output electromagnetic torque, converting it into three-phase alternating current through a synchronous generator module of engineering design or simulation software, and outputting it;

[0119] S200, adding a dynamic description of the tail gas output thereof based on the SOFC power generation model;

[0120] S300, introducing a dynamic description of bypass SOFC tail gas fuel input on the basis of the GT power generation model, thereby obtaining a SOFC-GT system integrated power generation dynamic model;

[0121] Here, SOFC stands for solid oxide fuel cell, and GT stands for gas turbine.

[0122] This embodiment further provides a SOFC-GT system integrated power generation coordinated control method, which is used to control the SOFC-GT system integrated power generation dynamic model obtained by the above-mentioned SOFC-GT system integrated power generation modeling method for microgrid application, and the SOFC-GT system integrated power generation coordinated control method includes:

[0123] Step S100, constructing a basic controller of a SOFC power generation unit and a basic controller of a GT power generation unit respectively;

[0124] Step S200, further constructing a top-level adaptive power allocation strategy to realize integrated power generation;

[0125] Wherein, in step S100, the construction of the basic controller of the SOFC power generation unit includes:

[0126] Step S111, obtaining the hydrogen molar flow rate and output current of the SOFC stack, and obtaining the fuel utilization rate;

[0127] Step S112, determining a target value of fuel utilization, and controlling the original fuel molar flow rate so that the fuel utilization is maintained near the target value of fuel utilization;

[0128] Step S113, obtaining the SOFC stack voltage and the internal inductor current of the Boost converter, determining a voltage target value, and controlling the DC bus voltage to be stable near the voltage target value;

[0129] Step S114, obtaining the inductor voltage and inductor current on the grid side, and obtaining the active power and reactive power output by the SOFC power generation unit, and obtaining the three-phase electrical frequency and phase angle of the grid through a phase-locked loop;

[0130] Step S115 obtains the voltage of the line capacitor and the current flowing through the inductor on the power supply side;

[0131] Step S116, designing a grid-following operation output power controller for the inverter to control the active power and reactive power output by the SOFC power generation unit in the grid-following mode;

[0132] Wherein, in step S100, the basic controller of the GT power generation unit is constructed, including:

[0133] Step S121, designing a speed governor for the GT power generation unit, wherein the speed governor can be switched between a grid-following mode and a grid-building mode according to the SOFC-GT system, and is used to stably control the speed of the gas turbine;

[0134] Wherein, in the grid-following mode, the speed governor has synchronization, and the speed governor can adjust the output power and rotor speed of the gas turbine without steady-state error. The relationship between the output power and the rotor speed is:

[0135] ;

[0136] in:

[0137] ;

[0138] ;

[0139] In the above formula, To control the amount of fuel supply, is the additional fuel compensation amount, is the scaling factor, is the gas turbine rotor speed, is the speed regulator time constant, is the Lagrangian operator, The fuel supply control quantity for the power stage, The fuel supply control quantity for the speed link, is the reference power output of the gas turbine, is the gas turbine output power, is the proportional link control gain, is the control gain of the first integral link, is the control gain of the second integral link, is the control gain of the third integral link, is the reference speed of the gas turbine rotor, is the droop coefficient;

[0140] Step S122, in the grid-building mode, when the speed regulator controls the frequency of the SOFC-GT system to maintain the rated frequency, the output power automatically tracks the actual load power demand, and the relationship between the rotor speed and the fuel supply control amount is:

[0141] ;

[0142] in, To control the amount of fuel supply, is the additional fuel compensation amount, is the scaling factor, is the gas turbine rotor speed, is the speed regulator time constant, is a pull operator, Provides control quantity of fuel supply for speed link;

[0143] Among them, the basic controller of the GT power generation unit is a gas turbine fuel controller designed to consider the bypass SOFC tail gas fuel input; the gas turbine fuel controller takes the rotor speed of the gas turbine at the previous moment and the electromagnetic power output of the generator as input;

[0144] Wherein, in step S200, the constructing of the top-level adaptive power allocation strategy includes:

[0145] S201, obtaining the hydrogen molar flow rate, output voltage and tail gas fuel molar flow rate of the SOFC stack;

[0146] S202, design a top-level online adaptive power allocation strategy;

[0147] The top-level online adaptive power allocation strategy uses the tail gas fuel molar flow rate as a reference to set the target power generation value of each power generation unit after the system reaches steady state, and the dynamic process before steady state is dynamically adaptively adjusted according to the current operating state of each power generation unit;

[0148] Furthermore, in the process of designing the gas turbine fuel controller that considers bypassing the SOFC tail gas fuel input: ensuring that the fuel supply is greater than or equal to the minimum warning value of the fuel input; for the fuel supply, in addition to the bypass input of the SOFC tail gas fuel, it is also necessary to directly provide additional fuel compensation to the gas turbine from the original fuel system;

[0149] For the fuel compensation, the following equation must be satisfied:

[0150] ;

[0151] in, is the additional fuel compensation amount, is the minimum warning value of fuel input, is the molar flow rate of exhaust fuel;

[0152] Furthermore, the control process of the basic controller of the GT power generation unit is:

[0153] When the SOFC-GT system is in the grid-following mode, the power loop control switch is in a closed state;

[0154] When the SOFC-GT system is in the grid-building mode, the power ring control switch is in an open state;

[0155] Further, in step S200, in the process of constructing the top-level adaptive power allocation strategy, the output power that the gas turbine should generate when supplied by the tail gas of the solid oxide fuel cell is:

[0156] ;

[0157] in, is the output power of the gas turbine, is the rated output power of the gas turbine, is the exhaust fuel molar flow rate, It is the minimum warning value of fuel input;

[0158] When the SOFC-GT system is in dynamic operation, the unsatisfied output power of the SOFC power generation unit will be borne entirely by the GT power generation module. When the system enters the steady-state operation stage, the target output power of the gas turbine is determined by the SOFC fuel tail gas flow rate.

[0159] The SOFC-GT system can quickly and accurately meet the total power demand;

[0160] As the total power demand changes, the fuel utilization of the solid oxide fuel cell is 0.7~0.9pu, and the overall fuel utilization of the system reaches 1p.u., and all fuels are fully utilized.

[0161] Example 3

[0162] In a first aspect, this embodiment provides a SOFC-GT system integrated power generation modeling method for microgrid applications, including:

[0163] S100, determining a SOFC power generation model and a GT power generation model;

[0164] The input of the SOFC power generation model is the output current of the SOFC stack at the last moment and the original fuel molar flow rate, and the output of the SOFC power generation model is the SOFC stack voltage and the molar flow rate of the tail gas; the input of the GT power generation model is the fuel supply control amount, the electromagnetic power output of the generator at the last moment and the rotor speed, and the output of the GT power generation model is three-phase alternating current;

[0165] The SOFC power generation model outputting the SOFC stack voltage may further include:

[0166] S111, the original fuel molar flow is converted into hydrogen molar flow after the fuel processing step;

[0167] S112, obtaining the gas partial pressure, and obtaining the Nernst voltage of the SOFC through the Nernst voltage equation;

[0168] S113, converting the numerical value into an electrical value through a controllable voltage source module within the engineering design or simulation software;

[0169] S114, simulating the ohmic polarization of the inside of the stack and the wires by equivalently connecting the series resistors, and then outputting the SOFC stack voltage through the SOFC power generation model;

[0170] The GT power generation model outputs three-phase alternating current, and may further include:

[0171] S121, the fuel supply control amount is passed through the valve and the fuel system link to obtain the fuel flow supplied by the fuel system;

[0172] S122, after being combined with the bypass SOFC tail gas fuel and then passing through the catalytic combustion delay link, the actual fuel input amount input to the gas turbine is obtained, and the input mechanical torque of the gas turbine is obtained;

[0173] S123, obtaining the speed of the gas turbine at the next moment through the difference between the mechanical torque of the gas turbine and the output electromagnetic torque, converting it into three-phase alternating current through a synchronous generator module of engineering design or simulation software, and outputting it;

[0174] S200, adding a dynamic description of the tail gas output thereof based on the SOFC power generation model;

[0175] S300, introducing a dynamic description of bypass SOFC tail gas fuel input on the basis of the GT power generation model, thereby obtaining a SOFC-GT system integrated power generation dynamic model;

[0176] Among them, SOFC stands for solid oxide fuel cell, GT stands for gas turbine;

[0177] Furthermore, for the SOFC power generation model, the SOFC stack output voltage, hydrogen molar flow rate, hydrogen partial pressure, oxygen partial pressure, water vapor partial pressure and tail gas fuel molar flow rate are obtained by the following formulas:

[0178] SOFC part: (1)

[0179] In the above formula, is the SOFC stack output voltage, is the molar flow rate of hydrogen, is the hydrogen partial pressure, is the partial pressure of oxygen, is the water vapor partial pressure, is the number of SOFC stack cells, is the electrode potential, is the gas constant, is the temperature, is the Faraday constant, is the original fuel molar flow rate, for The time constant, is a pull operator, is the hydrogen valve molar constant, is the proportionality coefficient, is the output current of the SOFC stack, is the time constant of hydrogen, is the oxygen valve molar constant, is the hydrogen-oxygen ratio, is the time constant of oxygen, is the time constant of water vapor, is the molar flow rate of exhaust fuel; is the ohmic polarization loss, , ;

[0180] For the GT power generation model, the fuel input, gas turbine output mechanical torque (Tm) and gas turbine (GT) rotor speed are obtained by the following formulas:

[0181] GT part: (2)

[0182] in, is the fuel input, is a natural constant, is a pull operator, is the combustion phase lag time, is the exhaust fuel molar flow rate, To control the amount of fuel supply, is the time constant of the intake valve link, is the time constant of the fuel system link, Output mechanical torque for the gas turbine, is the gas turbine rotor speed, is the electromagnetic torque, is the rotor time constant;

[0183] It should be noted that in the SOFC-GT system integrated power generation modeling method for microgrid application of this embodiment, the input quantity for the SOFC power generation model is the output current of the SOFC stack at the current moment. and the raw untreated fuel molar flow rate from the fuel system , original fuel molar flow rate After the fuel processing stage, it is converted into the hydrogen molar flow rate input into the flow channel of the SOFC stack. , and the molar flow of reactants and products consumed by the SOFC stack at the current moment can be measured by the output current Multiply by the proportionality factor As shown above, the difference between the two is obtained by the "pressure-flow" conversion formula corresponding to each component to obtain the gas partial pressure at the current moment. The gas partial pressure includes the hydrogen partial pressure. , oxygen partial pressure and water vapor pressure , and then the Nernst voltage is obtained through the Nernst voltage equation The numerical value is converted into electrical value through the controllable voltage source module in the engineering design or simulation software (such as MATLAB / Simulink), and the ohmic polarization caused by the interaction of the SOFC stack and the wires The equivalent simulation is performed through the series resistance, and the model output is finally obtained, that is, the output voltage of the SOFC stack ; Furthermore, for the GT dynamic model, the input is the fuel supply control amount , the electromagnetic power of the generator at the current moment and gas turbine rotor speed , fuel supply control amount The fuel flow rate supplied by the fuel system is obtained after passing through two typical lag links of the valve and the fuel system. Then, after the catalytic combustion delay stage, the actual fuel input to the gas turbine is obtained. , and then the gas turbine output mechanical torque is obtained through the gas turbine output mechanical torque formula , the gas turbine output mechanical torque With electromagnetic torque The gas turbine speed at the next moment is obtained by subtracting and combining with the rotor operation expression, and finally converted into three-phase AC output through the synchronous generator module in the engineering design or simulation software (such as MATLAB / Simulink). Therefore, this embodiment first adds a description of the dynamic process of its tail gas output on the basis of the original SOFC power generation model, and at the same time adds a description of the dynamic process of bypass SOFC tail gas fuel input on the basis of the original GT power generation model, and finally forms a SOFC-GT system integrated power generation dynamic model with "hydrogen-electricity" coupling.

[0184] In a second aspect, this embodiment further provides a SOFC-GT system integrated power generation coordinated control method, which is used to control the SOFC-GT system integrated power generation dynamic model obtained by the above-mentioned SOFC-GT system integrated power generation modeling method for microgrid application, and the SOFC-GT system integrated power generation coordinated control method includes:

[0185] Step 1: Collect the hydrogen molar flow rate of the SOFC stack With output current , calculate the fuel utilization ; Design fuel controller to control the original fuel molar flow To maintain fuel efficiency Maintain at target value The closed-loop control law is as follows:

[0186] (3)

[0187] in, is the hydrogen molar flow rate of the SOFC stack, is the fuel utilization rate, is the target value, is the proportional link control gain, is the integral link control gain, is the Lagrangian operator, for The time constant of

[0188] For fuel efficiency ,have:

[0189] (4)

[0190] in, is the fuel utilization rate, is the proportionality coefficient, is the SOFC output current, is the molar flow rate of hydrogen out of the SOFC reaction interface;

[0191] Step 2: Collect SOFC output voltage The internal inductor current of the Boost converter , design a voltage outer loop and current inner loop dual loop controller for boost converter to maintain DC bus voltage Stable near the target value to effectively deal with output voltage fluctuations caused by the polarization characteristics of solid oxide fuel cells (SOFCs);

[0192] For the DC / DC Boost converter, this embodiment adopts dual-loop voltage control, which is specifically expressed as follows:

[0193] (5)

[0194] in, is the duty cycle of the PWM drive signal, is the voltage reference / target value, is the SOFC output voltage, is the proportional link control gain, is the integral link control gain, is the Lagrangian operator, is the Boost converter inductor current, is the proportional link control gain, Control gain for the integral link;

[0195] Step 3: Collect the grid-side inductor voltage separately , inductor current , to obtain the output active power of the SOFC power generation unit and reactive power At the same time, the three-phase power frequency of the power grid is obtained through the phase-locked loop PLL Phase Angle ; At the same time, the line capacitance is collected separately Voltage , and the current flowing through the power supply side inductor Current ; Design a grid-following controller for the inverter to achieve the output active power of the SOFC power generation unit in the grid-following mode (GFL) / Reactive Power control;

[0196] Step 4: Based on the modified GT power generation unit model, a GT fuel controller is designed that considers the bypass SOFC tail gas fuel input; the controller is based on the gas turbine rotor speed. , Generator electromagnetic power The controller includes a speed control loop and a power control loop (the power control loop is equipped with an operation mode discrimination switch ), when the system is running in the grid-following mode (GFL), the discrimination switch is in the closed state ( ), to achieve the GT power generation unit running at the target speed and output power, and when the system is running in the grid / island mode (GFM), the discrimination switch is in the open state ( ), the power control loop is cut off and only the GT needs to be operated at the target speed, and the output power of the GT power generation unit changes with the load demand;

[0197] Furthermore, the design principle of the fuel controller in step 4 is as follows:

[0198] Considering that the exhaust gas flow of the solid oxide fuel cell will inevitably fluctuate when the gas turbine is inlet, it is necessary to ensure that the fuel provided to the gas turbine is always sufficient (i.e., the fuel input Fuel input minimum warning value ), in addition to the SOFC tail gas, additional fuel compensation is required directly from the fuel system For gas turbines, we have:

[0199] (6)

[0200] in, is the additional fuel compensation amount, is the minimum warning value of fuel input, is the molar flow rate of exhaust fuel;

[0201] Furthermore, a governor control has been developed for the GT generating unit to achieve seamless switching between the grid following mode (GFL) and the grid forming mode (GFM), see Figure 3 In the grid-following mode (GFL), the governor control has synchronous characteristics and can adjust the output power of the gas turbine without steady-state error. and rotor speed ( Also called operating frequency);

[0202] Furthermore, the output power and rotor speed The relationship is:

[0203] (7)

[0204] in:

[0205] (8)

[0206] (9)

[0207] In the above formula, To control the amount of fuel supply, is the additional fuel compensation amount, is the scaling factor, is the gas turbine rotor speed, is the speed regulator time constant, is the Lagrangian operator, The fuel supply control quantity for the power stage, The fuel supply control quantity for the speed link, is the reference power output of the gas turbine, is the gas turbine output power, is the proportional link control gain, is the control gain of the first integral link, is the control gain of the second integral link, is the control gain of the third integral link, is the reference speed of the gas turbine rotor, is the droop coefficient;

[0208] Furthermore, in the grid-building mode, when the speed governor controls the frequency of the SOFC-GT system to maintain the rated value, the output power automatically tracks the actual load power demand, and the relationship between the gas turbine rotor speed and the fuel supply control amount is:

[0209] (10)

[0210] in, To control the amount of fuel supply, is the additional fuel compensation amount, is the scaling factor, is the rotor speed, is the speed regulator time constant, is a pull operator, Provides control quantity of fuel supply for speed link;

[0211] It should be noted that the primary control algorithm of the GT power generation unit developed in this embodiment enables the SOFC-GT system (ISGS) integrated power generation to have the ability to operate in the grid-following mode and the grid-building mode, while ensuring that the gas turbine has sufficient fuel supply and maximizing the utilization rate of exhaust gas;

[0212] Step 5: Collect the hydrogen molar flow rate of the SOFC stack , output voltage , and the exhaust fuel molar flow rate , design the top-level online adaptive power allocation strategy based on the exhaust fuel molar flow The target power generation value of each power generation unit after the system is in steady state is set as a reference, and the dynamic process before steady state is dynamically adaptively adjusted according to the current operating state of each power generation unit, and finally the stable and safe operation of each power generation unit is ensured on the basis of achieving full utilization of tail gas. Compared with a single SOFC power generation unit, this embodiment greatly improves the power response speed of the system, and at the same time gives the system the ability to follow the grid and build a grid. In this process, the output power that the gas turbine can generate is:

[0213] (11)

[0214] in, is the output power of the gas turbine, is the rated output power of the gas turbine, is the exhaust fuel molar flow rate, It is the minimum warning value of fuel input;

[0215] Furthermore, when the SOFC-GT system (ISGS) operates to a steady state, the total power demand If constant, the gas turbine output reference power can be Set to the output power of the gas turbine In order to maximize the overall fuel utilization of the system, the remaining power demand Satisfied by SOFC power generation unit; as power demand To maximize the SOFC output power response speed while ensuring fuel utilization It has always been in the safe range (0.7-0.9pu), The value of is set to:

[0216] (12)

[0217] in, is the SOFC output power reference value, is the upper limit of power variation within the safe operating range of solid oxide fuel cells, is the lower limit of power variation within the safe operating range of solid oxide fuel cells, represents the remaining power requirement, Real-time power output for SOFC;

[0218] Furthermore, in the above formula:

[0219] ; (13)

[0220] ; (14)

[0221] in, is the upper limit of power variation within the safe operating range of solid oxide fuel cells, is the lower limit of power variation within the safe operating range of solid oxide fuel cells, is the SOFC stack output voltage, is the molar flow rate of hydrogen, is the proportionality coefficient;

[0222] In the above and If the remaining power requirement is met It is satisfied by the gas turbine; it should be noted that the strategy of this embodiment allocates appropriate power reference values ​​for the operation of solid oxide fuel cells and gas turbines. It is based on this regulation that the SOFC-GT system (ISGS) can quickly track the total power demand and maximize the use of system fuel while ensuring the safe operation of each power generation unit.

[0223] Furthermore, parameters are set based on the above-mentioned Example 3, and the actual effect is evaluated when the SOFC-GT system of Example 3 is operated in two operating modes, namely, the grid following mode (GFL) and the grid building mode (GFM), including:

[0224] (1) Parameter setting

[0225] To verify the effectiveness of Example 3, the key parameters of the SOFC-GT system are first set as follows:

[0226] The rated total output power of the system is 250KVA, the rated output power of the solid oxide fuel cell and the gas turbine is 150KVA (1p.u.) and 100KVA (1p.u.) respectively, the DC bus reference voltage is 800V, the rated fuel supply molar flow rate of the gas turbine is 1.2mol / s (1p.u.), and the droop coefficient is 0.04.

[0227] (2) Verification process

[0228] When the SOFC-GT system operates in the grid-following mode (GFL) and the grid-building mode (GFM), its actual effect is evaluated, mainly including the following two aspects: first, whether the total output power of the system and the work output of each power generation unit are met as expected when the power demand changes; second, whether the dynamic change process of each key parameter in the system is met as expected; the details are as follows:

[0229] See also Figure 4 and Figure 5 , the system is at the initial moment Running in GFL mode, Switch to GFM at all times, total power requirement The transition occurs at , and When the system is running in the GFL mode, The total power demand of the power grid at this moment is 180kW. The power demand is reduced to 130kW at any time. When the system is running in the grid-forming mode (GFM), the power output rises to 150kW at the same time, with a maximum change of 50kW. The initial power demand at the time is 170kW. It jumps to 150kW at any time, with a maximum change of 20kW.

[0230] (3) Verification results

[0231] See also Figures 4 to 6 , Figure 4 It shows that, regardless of the operating conditions, the collaborative control method of the present invention enables the SOFC-GT system (ISGS) to quickly meet the total power demand, and the power response is faster than the maximum response speed of the SOFC power generation unit. Under the action of the adaptive power allocation strategy, each power generation unit in the system can eventually reach its own target output power value. Figure 5 This shows the effectiveness of the primary control of the SOFC power generation unit and the GT power generation unit. It can be observed that the DC bus voltage and gas turbine rotor speed Under the control module, they can quickly and accurately track their reference values, exhaust fuel molar flow Can be fully utilized by gas turbines and fuel input is guaranteed Not less than the minimum warning value of fuel input Furthermore, the AC bus voltage waveform of the SOFC-GT system during the mode switching process is as follows: Figure 6As shown, a seamless transition of the SOFC-GT system from the grid-following mode (GFL) to the grid-building mode (GFM) can be observed, and a successful switch from the grid-connected mode to the islanded mode.

[0232] For further information, see Figures 1 to 3 , based on the above embodiments, for example, combined with Figures 1 to 3 The technical solution of the present invention is further described; wherein, Figure 1 The schematic diagram of the working process of the SOFC-GT system of the present invention is as follows: First, the grid dispatching center gives the total target output power of the system. To the local power adaptive allocation module, this module determines the output reference power value of each power generation unit according to the actual operating status of the SOFC power generation unit and the GT power generation unit in the current system, that is, the output reference power of the solid oxide fuel cell and the reference output power of the gas turbine ; Secondly, the SOFC power generation unit outputs a reference power according to the reference value solid oxide fuel cell By adjusting the fuel input flow, DC bus voltage and current inverter output power, the GT power generation unit outputs the required AC power to the grid / local load. Based on the SOFC tail gas flow, the GT power generation unit outputs the reference power of the gas turbine according to the reference value. The speed and output power of the gas turbine are adjusted by controlling the fuel flow through the speed governor, and then the required AC power is output to the grid / local load through the coaxial synchronous generator; finally, the SOFC-GT system outputs the AC power required by the total target power to achieve integrated power generation. Figure 2 It is a schematic diagram of the principle of the integrated power generation dynamic model of the SOFC-GT system of the present invention, Figure 2 The dynamic process of system integrated power generation is described in detail. The specific principle is as follows: For the SOFC power generation unit, the model input is the output current of the SOFC stack at the previous moment. and the original fuel molar flow rate, through the output current The molar flow rates of hydrogen and oxygen consumed and water generated are calculated respectively, and the difference is made with the input reactant flow rate and the gas partial pressure and tail gas molar flow rate are obtained through the first-order inertia link, and then the Nernst voltage is obtained through the Nernst voltage equation. Finally, the numerical value is converted into an electrical quantity through the controllable voltage source module in the engineering design or simulation software and the ohmic polarization is subtracted to obtain the output voltage of the SOFC power generation unit. For the GT power generation unit, the fuel supply control quantity The input flow is obtained by adding the molar flow of SOFC tail gas through the first-order inertial links such as the intake valve and the fuel system and through the hysteresis link of catalytic combustion. , combined with the gas turbine speed at the previous moment to obtain the current mechanical torque , and the speed of the gas turbine at the current moment is obtained by subtracting the speed from the electromagnetic torque at the previous moment through the rotor integration link, and the three-phase AC power is output through the synchronous generator module inside the engineering design or simulation software. Figure 3 is a schematic diagram of the principle of the collaborative control method of the present invention, Figure 3 The specific principle shown is as follows: First, the power grid dispatching center gives the total target output power of the system To the power distribution module, by obtaining the SOFC tail gas flow at the previous moment , SOFC hydrogen input flow rate and SOFC output voltage The output reference power value of each power generation unit is obtained through logical judgment, that is, the output reference power of the gas turbine and the reference output power of the gas turbine ; Secondly, for the SOFC power generation unit, its internal fuel control loop adopts PI control, the DC bus voltage adopts a dual-loop PI control with voltage outer loop and current inner loop, and the current-type inverter output power adopts a feedforward feedback composite dual-loop PI control; Finally, for the GT power generation unit, its internal speed regulator includes a speed control loop and a power control loop, both of which adopt PI control and are compounded in the integral part, and then by considering the exhaust gas flow The fuel supply control amount is obtained by the scaling rule , and finally input into the GT power generation unit sub-model to control it.

[0233] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0234] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A SOFC-GT system integrated power generation modeling method for microgrid applications, characterized in that: include: Determine the SOFC power generation model and GT power generation model; Based on the SOFC power generation model, a dynamic description of its tail gas output is added; Based on the GT power generation model, a dynamic description of bypass SOFC tail gas fuel input is introduced to obtain a SOFC-GT system integrated power generation dynamic model; Here, SOFC stands for solid oxide fuel cell, and GT stands for gas turbine.

2. The SOFC-GT system integrated power generation modeling method for microgrid application according to claim 1 is characterized in that: The input of the SOFC power generation model is the output current of the SOFC stack at the last moment and the original fuel molar flow rate; The output of the SOFC power generation model is the SOFC stack voltage and the molar flow rate of the tail gas; and / or, The input of the GT power generation model is the fuel supply control amount, the electromagnetic power output of the generator at the last moment, and the rotor speed; The output of the GT power generation model is three-phase alternating current.

3. The SOFC-GT system integrated power generation modeling method for microgrid application according to claim 2 is characterized in that: The SOFC power generation model outputs the SOFC stack voltage, including: The original fuel molar flow is converted into hydrogen molar flow after the fuel processing step; Obtain the gas partial pressure and obtain the Nernst voltage of SOFC through the Nernst voltage equation; Convert numerical quantities into electrical quantities through controllable voltage source modules within engineering design or simulation software; The ohmic polarization of the cell stack and the wires is simulated by equivalently simulating the ohmic polarization of the cell stack by series resistance, and then the SOFC cell stack voltage is outputted by the SOFC power generation model; and / or, The GT power generation model outputs three-phase alternating current, including: The fuel supply control quantity is obtained by passing through the valve and the fuel system link to obtain the fuel flow supplied by the fuel system; After being combined with the bypass SOFC tail gas fuel and then passing through the catalytic combustion delay link, the actual fuel input to the gas turbine is obtained, and the input mechanical torque of the gas turbine is obtained; The speed of the gas turbine at the next moment is obtained by the difference between the mechanical torque of the gas turbine and the output electromagnetic torque through the rotor link, and is converted into three-phase alternating current and output through the synchronous generator module of the engineering design or simulation software.

4. A SOFC-GT system integrated power generation coordinated control method, characterized in that: The SOFC-GT system integrated power generation dynamic model obtained by the SOFC-GT system integrated power generation modeling method for microgrid application according to any one of claims 1 to 3, the SOFC-GT system integrated power generation coordinated control method comprising: The basic controller of SOFC power generation unit and the basic controller of GT power generation unit are constructed respectively; then the top-level adaptive power allocation strategy is constructed to realize integrated power generation; among which: The basic controller of the SOFC power generation unit includes control of fuel input flow, DC bus voltage, and current-source inverter power output; The GT power generation unit basic controller includes GT output power and speed control considering bypass SOFC tail gas input; The top-level adaptive power allocation strategy determines the respective power output reference values ​​by acquiring the current operating status of each power generation unit, and finally realizes the integrated power generation of the system.

5. The SOFC-GT system integrated power generation coordinated control method according to claim 4, characterized in that: The construction of the basic controller of the SOFC power generation unit comprises: Obtain the hydrogen molar flow rate and output current of the SOFC stack, and obtain the fuel utilization rate; Determining a fuel utilization rate target value, and controlling the original fuel molar flow rate so that the fuel utilization rate is maintained near the fuel utilization rate target value; Obtaining the SOFC stack voltage and the internal inductor current of the Boost converter, determining a voltage target value, and controlling the DC bus voltage to be stable near the voltage target value; Obtain the inductor voltage and inductor current on the grid side, obtain the active power and reactive power output by the SOFC power generation unit, and obtain the three-phase electrical frequency and phase angle of the grid through a phase-locked loop; Obtain the voltage of the line capacitor and the current flowing through the inductor on the power supply side; An output power controller for grid-following operation is designed for the inverter to control the active power and reactive power output by the SOFC power generation unit in the grid-following mode.

6. The SOFC-GT system integrated power generation coordinated control method according to claim 4, characterized in that: Construct the basic controller of the GT power generation unit, including: A speed governor is designed for the GT power generation unit, and the speed governor can be switched between a grid-following mode and a grid-building mode according to the SOFC-GT system, so as to stably control the speed of the gas turbine; Wherein, in the grid-following mode, the speed governor has synchronization, and the speed governor can adjust the output power and rotor speed of the gas turbine without steady-state error. The relationship between the output power and the rotor speed is: ； in: ； ； In the above formula, To control the amount of fuel supply, is the additional fuel compensation amount, is the scaling factor, is the gas turbine rotor speed, is the speed regulator time constant, is the Lagrangian operator, The fuel supply control quantity for the power stage, The fuel supply control quantity for the speed link, is the reference power output of the gas turbine, is the gas turbine output power, is the proportional link control gain, is the control gain of the first integral link, is the control gain of the second integral link, is the control gain of the third integral link, is the reference speed of the gas turbine rotor, is the droop coefficient; In the grid-building mode, when the speed regulator controls the frequency of the SOFC-GT system to maintain the rated frequency, the output power automatically tracks the actual load power demand, and the relationship between the rotor speed and the fuel supply control amount is: ； in, To control the amount of fuel supply, is the additional fuel compensation amount, is the scaling factor, is the gas turbine rotor speed, is the speed regulator time constant, is a pull operator, Provides control quantity of fuel supply for speed link; Among them, the basic controller of the GT power generation unit is a gas turbine fuel controller designed to consider the bypass SOFC tail gas fuel input; the gas turbine fuel controller takes the rotor speed of the gas turbine at the previous moment and the electromagnetic power output of the generator as input.

7. The SOFC-GT system integrated power generation coordinated control method according to claim 6, characterized in that: The process of designing a gas turbine fuel controller that considers bypassing the SOFC tail gas fuel input: Ensure that the fuel supply is greater than or equal to the minimum warning value of fuel input; Regarding the supply amount of the fuel, in addition to the bypass input of the SOFC tail gas fuel, it is also necessary to directly provide additional fuel compensation to the gas turbine from the original fuel system; For the fuel compensation, the following equation must be satisfied: ； in, is the additional fuel compensation amount, is the minimum warning value of fuel input, is the molar flow rate of exhaust fuel.

8. The SOFC-GT system integrated power generation coordinated control method according to claim 7, characterized in that: The control process of the basic controller of the GT power generation unit is: When the SOFC-GT system is in the grid-following mode, the power loop control switch is in a closed state; When the SOFC-GT system is in the grid-building mode, the power ring control switch is in an open state.

9. The SOFC-GT system integrated power generation coordinated control method according to claim 4, characterized in that: The constructing of the top-level adaptive power allocation strategy includes: Obtaining hydrogen molar flow rate, output voltage and tail gas fuel molar flow rate of the SOFC stack; Design top-level online adaptive power allocation strategy; Among them, the top-level online adaptive power allocation strategy uses the exhaust fuel molar flow rate as a reference to set the target power generation value of each power generation unit after the system is in steady state, and the dynamic process before steady state is dynamically adaptively adjusted according to the current operating status of each power generation unit.

10. The SOFC-GT system integrated power generation coordinated control method according to claim 9, characterized in that: In the process of constructing the top-level adaptive power allocation strategy, the output power that the gas turbine should generate when supplied by the tail gas of the solid oxide fuel cell is: ； in, is the output power of the gas turbine, is the rated output power of the gas turbine, is the exhaust fuel molar flow rate, It is the minimum warning value of fuel input; When the SOFC-GT system is in dynamic operation, the unsatisfied output power of the SOFC power generation unit will be borne entirely by the GT power generation module. When the system enters the steady-state operation stage, the target output power of the gas turbine is determined by the SOFC fuel tail gas flow rate. The SOFC-GT system can quickly and accurately meet the total power demand; As the total power demand changes, the fuel utilization of the solid oxide fuel cell is 0.7~0.9pu, and the overall fuel utilization of the system reaches 1p.u., and all fuel is fully utilized.

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