A method and apparatus for stabilizing the fuel flow of a heavy gas turbine

Abstract

The present application relates to the technical field of gas turbine control, and discloses a heavy gas turbine fuel flow stability control method and device, comprising obtaining pressure temperature and component parameters, calling Joule-Thomson coefficient and real gas state equation, and calculating fluid thermodynamic parameters considering throttling effect; based on the parameters, parent pipe pressure and target flow, generating anti-blocking target pressure and calculating steady-state basic opening degree instruction; performing differential operation on intermediate pipe cavity pressure, and converting to generate dynamic feedforward compensation; determining static friction dead zone risk and generating asymmetric excitation pulse signal; superimposing the steady-state basic opening degree instruction, feedforward compensation and excitation pulse signal to generate the final control instruction. The present application improves the accuracy of flow calculation under low load conditions, avoids aerodynamic choking, and overcomes static friction and suppresses flow fluctuations through dynamic feedforward and excitation compensation, thereby improving the operating stability of the gas turbine.

Description

Technical Field

[0001] This invention relates to the field of gas turbine control technology, specifically to a method and apparatus for stable control of fuel flow in heavy-duty gas turbines. Background Technology

[0002] As a power generation device, the operational stability and combustion efficiency of heavy-duty gas turbines largely depend on the stable control of the fuel supply system. The fuel flow control valve is the actuator of the gas turbine's fuel supply system, and its response characteristics directly affect the stability of the fuel flow.

[0003] During gas turbine ignition and low-load operation, the fuel pipeline system operates at low flow rates and high pressure differentials. When fuel gases such as natural gas flow through the control valve, their temperature drops due to the Joule-Thomson effect, leading to a change in gas density. Existing control methods, if they ignore this throttling and cooling effect or use a simplified gas state model when calculating fuel flow, will introduce density calculation errors, which in turn will cause deviations in flow control.

[0004] Meanwhile, the high pressure differential condition also poses a risk of gas dynamic sonic blockage to the control valve. Once the critical flow state is reached, the downstream flow rate will no longer change with the increase of upstream pressure or valve opening, causing the control system to lose its ability to regulate the flow rate, which affects combustion stability.

[0005] In addition, pressure pulsations and other disturbances in the fuel supply pipeline are common. As a mechanical device, the flow control valve has static friction and hysteresis characteristics between its internal components such as the valve stem and actuator. When the control system outputs a small adjustment command to counteract these disturbances, the valve cannot overcome the static friction and generates a response dead zone, which manifests as delayed or discontinuous movement, ultimately causing unexpected fluctuations in fuel flow and affecting the stable operation of the unit. Summary of the Invention

[0006] The technical problem addressed by this invention is that, under ignition and low-load conditions, the fuel gas circuit system of existing heavy-duty gas turbines operates in a low-flow, high-pressure differential state. When the gas fluid flows through valves, a throttling and cooling effect occurs, affecting the calculated fluid density and flow rate. Simultaneously, the flow control valve faces the physical risk of gas dynamic sonic blockage during throttling and pressure regulation. Furthermore, when external disturbances such as pressure pulsations occur in the fuel pipeline, the inherent mechanical static friction of the internal components of the flow control valve can create an opening dead zone under small command responses, leading to lag or discontinuous valve action, which in turn causes fuel flow fluctuations, affecting the aerodynamic stability of gas turbine ignition and operation.

[0007] To address the above problems, the present invention provides the following technical solution:

[0008] The first aspect of this invention provides a method for stabilizing fuel flow in a heavy-duty gas turbine, comprising: The first absolute pressure signal and the first absolute temperature signal upstream of the pressure regulating shut-off valve, the pressure signal of the intermediate cavity in the intermediate pipeline, and the natural gas component parameters are obtained, and the fluid thermodynamic parameters of natural gas are calculated. Based on the fluid thermodynamic parameters, the intermediate pipe pressure signal, the actual pressure signal of the main pipe inside the combustion chamber main pipe and the target set flow rate, a target set pressure for controlling the pressure regulating shut-off valve is generated, and a steady-state basic opening command for the flow control valve is calculated. The intermediate cavity pressure signal is subjected to time differentiation operation, and the transient mass flow rate deviation is calculated in combination with local aerodynamic sensitivity. The transient mass flow rate deviation is then converted into a dynamic feedforward compensation amount that matches the steady-state basic opening command. The polarity of the dynamic feedforward compensation is determined and an asymmetric excitation pulse signal is generated. The asymmetric excitation pulse signal, the dynamic feedforward compensation, and the steady-state basic opening command are superimposed to generate the final control command, which is then sent to the control valve servo positioner.

[0009] Further, the first absolute pressure signal and the first absolute temperature signal upstream of the pressure regulating shut-off valve, the intermediate cavity pressure signal in the intermediate pipeline, and the natural gas component parameters are acquired to calculate the fluid thermodynamic parameters of the natural gas. This includes: acquiring the natural gas component parameters, the first absolute pressure signal, the first absolute temperature signal, and the intermediate cavity pressure signal; retrieving the corresponding Joule-Thomson coefficient from the built-in fluid property database; comparing the values ​​of the acquired first absolute pressure signal and the intermediate cavity pressure signal; when the first absolute pressure signal is greater than the intermediate cavity pressure signal, using the transient temperature correction formula, and utilizing the first absolute pressure signal, the first absolute temperature signal, the intermediate cavity pressure signal, and the Joule-Thomson coefficient, to calculate the transient fluid calculation temperature, thereby obtaining the transient fluid calculation temperature after compensating for the throttling effect.

[0010] Furthermore, the calculation of the fluid thermodynamic parameters of natural gas also includes: using the transient fluid calculation temperature, the intermediate pipeline pressure signal, and the natural gas component parameters as input boundary conditions, substituting them into the real gas state equation of natural gas for solution, to obtain the dynamic compressibility factor and specific heat ratio of natural gas; the fluid thermodynamic parameters are constituted by the transient fluid calculation temperature, the dynamic compressibility factor of natural gas, and the specific heat ratio of gas.

[0011] Further, based on the fluid thermodynamic parameters, the intermediate pipe pressure signal, the actual pressure signal of the main pipe inside the combustion chamber main pipe, and the target set flow rate, a target set pressure for controlling the pressure regulating shut-off valve is generated, including: acquiring the target set flow rate; performing table lookup or interpolation calculations based on the pre-calibrated correspondence between the target set flow rate and the intermediate pipe target pressure, and outputting the corresponding basic mapping pressure benchmark; using an anti-blocking limit constraint formula, calculating the critical blockage occurrence pressure using the actual pressure signal of the main pipe and the gas specific heat ratio in the fluid thermodynamic parameters; combining the system's preset anti-blocking pressure margin, performing boundary constraint optimization calculations on the basic mapping pressure benchmark and the critical blockage occurrence pressure to generate the target set pressure; comparing the target set pressure with the intermediate pipe pressure signal, and generating a pressure regulating opening command to control the pressure regulating shut-off valve.

[0012] Furthermore, based on the fluid thermodynamic parameters, the intermediate cavity pressure signal, the actual pressure signal of the main pipe inside the combustion chamber main pipe, and the target set flow rate, a steady-state basic opening command for the flow control valve is calculated, including: reading the target set flow rate, the intermediate cavity pressure signal, the actual pressure signal of the main pipe, and the fluid thermodynamic parameters; substituting them into the compressible fluid valve flow equation; and solving in reverse to obtain the valve flow capacity coefficient; calling the inherent flow characteristic curve of the flow control valve; converting the valve flow capacity coefficient into the corresponding physical valve stroke percentage; and generating the steady-state basic opening command for the flow control valve.

[0013] Further, performing time differentiation on the intermediate lumen pressure signal includes: acquiring the intermediate lumen pressure signal, performing filtering using a first-order low-pass digital filter at the differential operation front end; performing the time differentiation operation on the filtered intermediate lumen pressure signal, and extracting the lumen pressure change rate for feedforward compensation calculation.

[0014] Furthermore, the transient mass flow rate deviation is calculated by combining local pneumatic sensitivity, and the transient mass flow rate deviation is converted into a dynamic feedforward compensation amount to match the steady-state basic opening command. This includes: calculating the partial derivatives of the intermediate cavity pressure signal and the valve mechanical opening according to the compressible fluid valve flow equation, respectively, to obtain the control valve pneumatic pressure sensitivity and control valve mechanical displacement sensitivity as local pneumatic sensitivity parameters; multiplying the extracted cavity pressure change rate with the control valve pneumatic pressure sensitivity to calculate the transient mass flow rate deviation caused by pressure disturbance; introducing the actuator mechanical delay time constant, and using the feedforward compensation conversion formula, the transient mass flow rate deviation is converted into the dynamic feedforward compensation amount representing the advance action margin required to match the steady-state basic opening command.

[0015] Further, determining the polarity of the dynamic feedforward compensation amount and generating an asymmetric excitation pulse signal includes: receiving the dynamic feedforward compensation amount; when it is detected that the dynamic feedforward compensation amount in the current operation cycle and the dynamic feedforward compensation amount in the previous operation cycle satisfy an opposite polarity relationship, and the absolute value of the current dynamic feedforward compensation amount is not greater than the system's preset opening dead zone judgment threshold, determining that there is a mechanical static friction opening dead zone risk and triggering the high-frequency excitation logic for getting out of trouble; wherein, the opening dead zone judgment threshold is set to 0.5% to 1.5% based on the historical operating data of the gas turbine TCS system and the factory hysteresis test curve of the flow control valve; when the high-frequency excitation logic for getting out of trouble is triggered, an asymmetric excitation pulse generation formula related to the feedforward compensation direction is used to adaptively generate the asymmetric excitation pulse signal according to the actual polarity direction of the dynamic feedforward compensation amount.

[0016] A second aspect of the present invention provides a fuel flow stabilization control device for heavy-duty gas turbines, comprising: The thermophysical property calculation module is used to acquire the first absolute pressure signal, the first absolute temperature signal, the intermediate pipeline pressure signal, and the natural gas component parameters, and to calculate the fluid thermodynamic parameters of the natural gas. The basic opening calculation module is used to receive the fluid thermodynamic parameters, and combine the intermediate pipe cavity pressure signal, the main pipe actual pressure signal and the target set flow rate to generate the target set pressure of the intermediate pipe to control the pressure regulating shut-off valve. At the same time, it calculates the steady-state basic opening command of the flow control valve. The feedforward compensation calculation module is used to perform differential operations on the intermediate cavity pressure signal to obtain the cavity pressure change rate, and then calculate the transient mass flow rate deviation, and convert the transient mass flow rate deviation into a dynamic feedforward compensation amount that matches the steady-state basic opening command; The instruction synthesis excitation module is used to integrate the steady-state basic opening instruction with the dynamic feedforward compensation amount, and combine it with the generated asymmetric excitation pulse signal to generate the final control instruction, and send the final control instruction to the control valve servo positioner.

[0017] In a preferred embodiment of the present invention, the instruction synthesis excitation module is used to generate an asymmetric excitation pulse signal, and to superimpose the asymmetric excitation pulse signal, the steady-state basic opening command, and the dynamic feedforward compensation amount to generate a final control command. Specifically, the instruction synthesis excitation module is used to: determine whether the flow control valve has a risk of entering the mechanical static friction opening dead zone; when the mechanical static friction opening dead zone risk exists, the dead zone trigger flag is activated, the asymmetric excitation pulse signal is generated, and the steady-state basic opening command, the dynamic feedforward compensation amount, and the asymmetric excitation pulse signal are superimposed in the time domain in the digital computing domain to generate the final control command.

[0018] In a preferred embodiment of the present invention, the thermophysical property calculation module acquires a first absolute pressure signal, a first absolute temperature signal, an intermediate pipe pressure signal, and natural gas component parameters, and calculates the fluid thermodynamic parameters of natural gas. Specifically, it is used to: acquire the natural gas component parameters, the first absolute pressure signal, the first absolute temperature signal, and the intermediate pipe pressure signal; call the corresponding Joule-Thomson coefficient; compare the values ​​of the acquired first absolute pressure signal and the intermediate pipe pressure signal; when the first absolute pressure signal is greater than the intermediate pipe pressure signal, use the transient temperature correction formula, and use the first absolute pressure signal, the first absolute temperature signal, the intermediate pipe pressure signal, and the Joule-Thomson coefficient to obtain the transient fluid calculation temperature after compensating for the throttling effect.

[0019] In a preferred embodiment of the present invention, the thermodynamic parameters of natural gas calculated by the thermodynamic property calculation module are further used to: take the transient fluid calculation temperature, the intermediate cavity pressure signal and the natural gas component parameters as input boundary conditions, substitute them into the real gas state equation of natural gas for solution, and obtain the dynamic compressibility factor and specific heat ratio of natural gas, which constitute the thermodynamic parameters of natural gas.

[0020] In a preferred embodiment of the present invention, the basic opening calculation module generates the target set pressure to control the pressure regulating shut-off valve. Specifically, it is used to: perform lookup table or interpolation calculation based on the obtained target set flow rate and the correspondence between the pre-calibrated target set flow rate and the intermediate pipeline target pressure, output the basic mapping pressure benchmark, and calculate the critical blockage occurrence pressure using the actual pressure signal of the main pipe using the anti-blockage limit constraint formula; combine the anti-blockage pressure margin to perform constraint optimization calculation on the basic mapping pressure benchmark and the critical blockage occurrence pressure to generate the target set pressure; compare the target set pressure with the intermediate pipeline pressure signal to generate a pressure regulating opening command to control the pressure regulating shut-off valve.

[0021] In a preferred embodiment of the present invention, the feedforward compensation calculation module extracts the differential rate of change of the intermediate cavity pressure signal to calculate the dynamic feedforward compensation amount. Specifically, it is used to: acquire the intermediate cavity pressure signal and perform a first-order low-pass digital filter followed by time differentiation to obtain the cavity pressure rate of change; calculate and extract the transient mass flow rate deviation based on the cavity pressure rate of change, and use the feedforward compensation conversion formula to convert the transient mass flow rate deviation to obtain the advance action margin required to match the steady-state basic opening command, and generate the dynamic feedforward compensation amount.

[0022] In a preferred embodiment of the present invention, the instruction synthesis excitation module generates the asymmetric excitation pulse signal, specifically for: when the dead zone trigger flag takes effect and triggers the high-frequency excitation logic for escaping, using the asymmetric excitation pulse generation formula; and adaptively generating the asymmetric excitation pulse signal according to the polarity direction of the obtained dynamic feedforward compensation amount.

[0023] In a preferred embodiment of the present invention, an internal unified clock is used to synchronously sample and hold the acquired first absolute pressure signal, the first absolute temperature signal, and the intermediate cavity pressure signal.

[0024] This invention provides a method and apparatus for stabilizing fuel flow in heavy-duty gas turbines. It offers the following advantages: 1. This invention corrects the front-end temperature signal by obtaining the natural gas composition and Joule-Thomson coefficient, and substitutes them into the real gas equation of state to obtain the dynamic compressibility factor and specific heat ratio of natural gas. This method reduces the interference of the throttling cooling effect on fluid density assessment under low flow and high pressure differential conditions of gas turbines, and improves the accuracy of fuel fluid thermodynamic parameters and steady-state basic opening calculations.

[0025] 2. This invention calculates the critical blockage pressure using the actual pressure of the main pipe and the specific heat ratio of the gas, and optimizes the target setting pressure of the pressure regulating shut-off valve by combining the anti-blockage pressure margin. This method limits the pressure build-up target upstream of the flow control valve to a range below the aerodynamic critical point, avoiding gas dynamic sonic blockage during the throttling and pressure regulation process, and maintaining the valve's physical regulation margin.

[0026] 3. This invention extracts the pressure change rate by performing differential operations on the pipe pressure signal to generate a dynamic feedforward compensation quantity. When a risk of mechanical static friction dead zone is detected, an asymmetric excitation pulse signal is generated and superimposed for output. This method reduces the static friction resistance of internal valve components, overcomes the problems of valve action lag and discontinuity under small command responses, reduces fuel flow fluctuations caused by external disturbances, and improves the aerodynamic stability of the gas turbine. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall architecture of a heavy-duty gas turbine fuel control system proposed in an embodiment of the present invention; Figure 2 This is a flowchart of a method for stabilizing fuel flow in a heavy-duty gas turbine, as proposed in an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the control principle of a specific fuel flow stabilization control method proposed in an embodiment of the present invention; Figure 4 This is a boundary diagram of the lumen pressure disturbance according to the present invention; Figure 5 This is a comparison diagram of the controller output commands of the present invention; Figure 6 This is a comparison diagram of the physical valve action response of the present invention. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] See attached document Figure 1 The present invention provides a fuel flow stabilization control device for heavy-duty gas turbines, which may include: a pressure regulating shut-off valve, an intermediate pipeline, a flow control valve, and a control device; The pressure regulating shut-off valve, intermediate pipeline, and flow control valve are connected sequentially along the flow direction of the gas turbine fuel gas; the first pressure transmitter and the first temperature transmitter are installed on the upstream pipeline of the pressure regulating shut-off valve; the second pressure transmitter is installed on the intermediate pipeline; and the third pressure transmitter is installed on the combustion chamber main pipeline. The first pressure transmitter, the first temperature transmitter, the second pressure transmitter, the third pressure transmitter, the pressure regulating valve servo positioner, and the control valve servo positioner are all electrically connected to the control device. The control device receives externally input system operation requirements parameters and natural gas composition parameters. The pressure regulating shut-off valve is used to regulate the flow rate of fuel gas entering the intermediate pipeline and to perform fuel gas shut-off action under abnormal operating conditions. The intermediate pipe receives the gas fluid and guides it to the flow control valve; the flow control valve controls the gas flowing through the interior and discharges it into the combustion chamber header. The first pressure transmitter acquires the first absolute pressure signal at the front end of the pressure regulating shut-off valve. The first temperature transmitter acquires the first absolute temperature signal at the front end of the pressure regulating shut-off valve. The second pressure transmitter collects the pressure signal of the intermediate cavity in the intermediate pipeline. The third pressure transmitter collects the actual pressure signal of the main pipe inside the combustion chamber main pipe; The control device acquires the first absolute pressure signal, the first absolute temperature signal, the intermediate pipe pressure signal, the main pipe actual pressure signal, and natural gas component parameters. It is internally equipped with a thermophysical property calculation module, a basic opening calculation module, a feedforward compensation calculation module, and a command synthesis excitation module. The thermodynamic property calculation module uses the first absolute pressure signal, the first absolute temperature signal, the intermediate pipe pressure signal, and the natural gas component parameters to calculate the fluid thermodynamic parameters of natural gas. The basic opening calculation module generates the target set pressure of the intermediate pipeline and forms the pressure regulating opening command of the pressure regulating shut-off valve based on the deviation between the target set pressure and the pressure signal of the intermediate pipeline cavity. The pressure regulating opening command is then sent to the pressure regulating valve servo positioner. Meanwhile, the basic opening calculation module combines fluid thermodynamic parameters, intermediate tube pressure signal, actual main tube pressure signal and target set flow rate input from outside the system to calculate the steady-state basic opening command of the flow control valve; The feedforward compensation calculation module extracts the differential rate of change of the intermediate lumen pressure signal to calculate the dynamic feedforward compensation amount that matches the steady-state basic opening command. The command synthesis excitation module integrates the steady-state basic opening command and the dynamic feedforward compensation to generate the final control command, and sends the final control command to the control valve servo positioner.

[0030] See attached document Figure 2 This invention provides a method for stable control of fuel flow in a heavy-duty gas turbine, comprising the following steps: S1, State parameter calculation: Obtain the first absolute pressure signal, the first absolute temperature signal, the intermediate pipe pressure signal, and the natural gas component parameters, and calculate the fluid thermodynamic parameters of natural gas. S2, basic opening inversion, generates target set pressure for controlling pressure regulating shut-off valve, and calculates steady-state basic opening command for flow control valve based on fluid thermodynamic parameters, intermediate cavity pressure signal, actual main pipe pressure signal and target set flow rate. S3, feedforward compensation extraction, performs time differentiation operation on the intermediate tube pressure signal, calculates the transient mass flow rate deviation by combining local aerodynamic sensitivity, and converts it into a dynamic feedforward compensation amount to match the steady-state basic opening command; S4, excitation superposition output, determines the polarity of dynamic feedforward compensation and generates an asymmetric excitation pulse signal, superimposes the asymmetric excitation pulse signal, dynamic feedforward compensation and steady-state basic opening command to generate the final control command and sends it to the control valve servo positioner.

[0031] The control execution process of each of the above steps will be explained in detail below, taking into account the specific characteristics of the model.

[0032] For the process of obtaining the first absolute pressure signal, the first absolute temperature signal, the intermediate pipeline pressure signal, and the natural gas component parameters in step S1, and calculating the fluid thermodynamic parameters of natural gas, the thermophysical property calculation module inside the control device performs the following sub-step operations.

[0033] S101, During system operation, the control device periodically collects physical feedback quantities from each monitoring point through the underlying electrical interface. Specifically, the control device acquires the first absolute pressure signal transmitted by the first pressure transmitter, the first absolute temperature signal transmitted by the first temperature transmitter, and the intermediate pipeline pressure signal transmitted by the second pressure transmitter. To ensure alignment of different physical quantities at the same time cross-section, the control device uses an internal unified clock to synchronously sample and hold the aforementioned analog signals. Simultaneously, the thermophysical property calculation module acquires the natural gas composition parameters of the system.

[0034] In this embodiment, the natural gas composition parameters can be transmitted from the gas turbine upper-level distributed control system to the control device. Alternatively, they can be measured in real-time and transmitted to the control device via an online gas chromatograph mounted on the intake pipeline. These natural gas composition parameters typically include the real-time mole fractions of combustible components such as methane, ethane, and propane, as well as inert gases such as nitrogen and carbon dioxide. Based on the acquired natural gas composition parameters, the first absolute pressure signal, the first absolute temperature signal, and the intermediate cavity pressure signal, the thermophysical property calculation module retrieves the corresponding Joule-Thomson coefficients from the built-in fluid property database. Preferably, the Joule-Thomson coefficients are obtained by interpolation using a two-dimensional or multi-dimensional data table indexed by gas composition, pressure, and temperature, with the pressure unit consistent with the pressure unit in the subsequent transient temperature correction formula.

[0035] S102. Considering that under low-flow ignition conditions, the gas fluid experiences a pressure drop when flowing through the pressure regulating shut-off valve, triggering a throttling and cooling effect in fluid thermodynamics. From a physical perspective, natural gas undergoes isenthalpic throttling expansion as it passes through the valve's constriction. Due to the increased intermolecular distance, work must be done to overcome intermolecular forces, consuming internal heat energy and ultimately resulting in a decrease in macroscopic fluid temperature. Under these conditions, the gas temperature inside the intermediate pipeline is often lower than the upstream temperature of the pressure regulating shut-off valve. Directly using the first absolute temperature signal as the calculation boundary for the gas inside the intermediate pipeline can easily introduce calculation errors in subsequent flow inversion.

[0036] To avoid algorithmic errors caused by unit shutdown or abnormal sensor data, the thermophysical property calculation module first compares the values ​​of the first absolute pressure signal and the intermediate cavity pressure signal before inputting them into the formula. When the first absolute pressure signal is less than or equal to the intermediate cavity pressure signal, the thermophysical property calculation module directly assigns the first absolute temperature signal to the transient fluid calculation temperature; when the first absolute pressure signal is greater than the intermediate cavity pressure signal, the thermophysical property calculation module uses the transient temperature correction formula to calculate the transient fluid calculation temperature. The transient temperature correction formula is as follows: ; in, This indicates the temperature calculated for transient fluid. This represents the first absolute temperature signal. This represents the Joule-Thomson coefficient. This indicates the first absolute pressure signal. This indicates the pressure signal in the intermediate cavity; This indicates the pressure difference across the pressure regulating shut-off valve. This indicates the correction amount for throttling and cooling. and The same pressure unit is used. Using this formula, the thermal property calculation module obtains the transient fluid calculation temperature after compensating for the throttling effect.

[0037] S103, after obtaining the corrected temperature boundary, the thermal property calculation module continues to calculate the relevant parameters of the gas equation of state. In specific operation, the thermal property calculation module uses the transient fluid calculation temperature, intermediate cavity pressure signal, and natural gas component parameters obtained above as input boundary conditions, and substitutes them into the real gas equation of state of natural gas for multi-dimensional online iterative optimization.

[0038] In this embodiment, the real gas equation of state adopts the industry-recognized AGA8 standard model equation. The thermophysical property calculation module obtains the dynamic compressibility factor of natural gas and density and compressibility correction parameters related to the real gas state by solving the AGA8 standard model equation; simultaneously, it calculates the gas specific heat ratio by combining the isobaric specific heat, isochoric specific heat, or sound velocity calculation relationships corresponding to the natural gas component parameters. Since pressure fluctuations exist in the intermediate pipeline during the ignition stage, the gas no longer conforms to the ideal gas law; therefore, introducing the real-time natural gas dynamic compressibility factor can effectively correct the influence of intermolecular forces on volume caused by high-pressure gas.

[0039] Ultimately, the transient fluid calculation temperature, natural gas dynamic compressibility factor, and gas specific heat ratio obtained from this step together constitute the fluid thermodynamic parameters required in the aforementioned step S1. These fluid thermodynamic parameters are refreshed in real time within the independent operation cycle of the control device and provided to the basic opening calculation module to execute the subsequent opening inversion logic.

[0040] For the process of generating the target set pressure and calculating the steady-state foundation opening command in step S2, the foundation opening calculation module inside the control device performs the following sub-step operations.

[0041] S201, During system operation, the basic opening calculation module receives the target set flow rate input from outside the system. In this embodiment, the basic opening calculation module has a built-in pre-calibrated correspondence between the target set flow rate and the target pressure of the intermediate pipeline. This correspondence is used to characterize the desired gas pressure reference required to maintain combustion in the intermediate pipeline under different load conditions of the gas turbine. The correspondence can be stored in the control device in the form of a calibration data table, a piecewise function model, or a lookup table interpolation model. The basic opening calculation module uses the target set flow rate as a retrieval parameter, performs lookup table or interpolation calculations based on the correspondence, and then outputs the corresponding basic mapped pressure reference. For the specific mathematical implementation process of linear interpolation calculation, those skilled in the art can consult relevant numerical analysis materials, and its interpolation solution method is a well-known technology in the field, and will not be elaborated here.

[0042] S202, considering the physical risk of gas dynamic sonic blockage during the throttling and pressure regulation process of the flow control valve, when the pressure difference across the valve reaches the corresponding aerodynamic conditions causing the gas velocity to reach the local sonic velocity, the mass flow rate through the valve will no longer increase with the decrease in downstream pressure. To ensure that the flow control valve has the expected regulation margin, the basic opening calculation module, combined with the back pressure boundary on the combustion chamber side, performs multi-boundary constraint optimization calculations on the aforementioned basic mapped pressure benchmark. Based on this, the basic opening calculation module extracts the gas specific heat ratio from the fluid thermodynamic parameters calculated in the aforementioned steps and simultaneously acquires the actual pressure signal of the main pipe collected by the third pressure transmitter.

[0043] To prevent sensor malfunctions or communication anomalies from causing the gas specific heat ratio input value to be equal to or less than 1, thus triggering an error in the division-by-zero operation of the calculation formula, the basic opening calculation module performs a lower limit threshold clamping protection on the gas specific heat ratio before performing mathematical calculations to ensure that its value is always greater than 1. After completing the data validity verification, the basic opening calculation module 62 uses an anti-blocking limiting constraint formula to calculate the target set pressure used to control the pressure regulating shut-off valve 10. The anti-blocking limiting constraint formula is as follows: ; ; in, This indicates the pressure at which critical blockage occurs. This indicates the actual pressure signal of the main pipe. Indicates the specific heat ratio of a gas. This represents the intermediate variable in isentropic expansion. This represents the variable representing the power term of the adiabatic exponent; This indicates that setting goals will put pressure on you. This represents the function that performs the minimum value operation. Indicates the base mapping pressure benchmark. Indicates the pressure margin for preventing blockage. This indicates the upper limit pressure for noncritical flow safety.

[0044] Through the aforementioned constraints, the target set pressure is limited to a safe range below the critical blockage pressure, thereby reducing the risk of the flow control valve entering a pneumatic blockage state. Subsequently, the basic opening calculation module uses this target set pressure as the given value for the pressure closed loop and compares it with the intermediate pipeline pressure signal acquired by the second pressure transmitter to generate a pressure regulating opening command for the pressure regulating shut-off valve. The control device sends this pressure regulating opening command to the pressure regulating valve servo positioner, which drives the pressure regulating shut-off valve to actuate, so that the pressure in the intermediate pipeline approaches the target set pressure.

[0045] S203, after determining the pressure build-up target of the intermediate pipeline and completing the boundary constraints, the basic opening calculation module performs back-calculation of the flow control valve opening based on the actual fluid state. The basic opening calculation module reads the target set flow rate, the intermediate pipeline pressure signal, and the actual main pipe pressure signal, and extracts complete fluid thermodynamic parameters, including transient fluid calculation temperature, natural gas dynamic compressibility factor, and gas specific heat ratio. Since the gas undergoes corresponding density expansion changes when flowing through the constriction section inside the valve, the basic opening calculation module substitutes these parameters as known quantities into the compressible fluid valve flow equation, and solves in reverse the process to obtain the valve flow capacity coefficient necessary to maintain the target flow rate under the current operating conditions.

[0046] In this embodiment, the basic opening calculation module first determines the flow state of the flow control valve based on the intermediate pipe pressure signal and the actual main pipe pressure signal. When the determination result is in the non-critical flow range, the compressible fluid valve flow equation adopts the non-critical flow aerodynamic calculation model specified in the industrial standard ANSI / ISA-75.01.01; when the determination result is close to the critical flow boundary, the basic opening calculation module prioritizes the aforementioned anti-blocking pressure constraint and performs steady-state basic opening inversion under the constrained pressure boundary. After calculating the valve flow capacity coefficient, the basic opening calculation module calls the inherent flow characteristic curve of the flow control valve stored in the control device. The basic opening calculation module uses the valve flow capacity coefficient as the abscissa input, maps it according to the inherent flow characteristic curve, converts it into the corresponding physical valve stroke percentage, and thus generates a steady-state basic opening command for the flow control valve. This steady-state basic opening command serves as the reference feedforward for flow regulation and participates in the command synthesis control logic of subsequent steps.

[0047] For step S3, which involves performing time differential calculation on the intermediate cavity pressure signal, calculating the transient mass flow rate deviation in conjunction with local aerodynamic sensitivity, and converting it into a dynamic feedforward compensation amount to match the steady-state basic opening command, the feedforward compensation calculation module inside the control device performs the following sub-step operations.

[0048] S301, during system operation, the feedforward compensation calculation module acquires the intermediate pipe cavity pressure signal continuously collected by the second pressure transmitter in real time. To calculate the pressure change trend inside the pipeline, the feedforward compensation calculation module performs time differentiation on the collected intermediate pipe cavity pressure signal to extract its rate of change in the time dimension. Since pulsation in the field pressure guide pipe and the operation of electrical equipment often superimpose high-frequency random noise onto the sensor signal, direct differentiation can easily amplify this high-frequency noise. Therefore, the feedforward compensation calculation module is equipped with a first-order low-pass digital filter at the front end of the differentiation operation. As a preferred method, the feedforward compensation calculation module uses the filter coefficient formula to calculate the filter coefficient, which is: ; in, Represents the filter coefficients. Represents the natural constant. Represents pi (π). Indicates the filter cutoff frequency. Indicates the sampling period. This represents the discretization decay exponent.

[0049] The feedforward compensation calculation module uses a first-order low-pass digital filter formula to calculate the filtered intermediate cavity pressure signal at the current moment. The first-order low-pass digital filter formula is as follows: ; in, This represents the filtered pressure signal in the intermediate cavity at the current moment. This represents the filtered pressure signal in the intermediate cavity from the previous moment. This indicates the pressure signal in the intermediate cavity at the current moment. Indicates the current discrete sampling time. Indicates the previous discrete sampling time. This represents the complementary filter coefficients.

[0050] The feedforward compensation calculation module uses the differential formula for calculating the rate of change of lumen pressure to calculate the rate of change of lumen pressure. The differential formula for calculating lumen pressure is as follows: ; in, Indicates the rate of change of pressure in the lumen. This indicates the pressure increment between adjacent sampling periods.

[0051] Therefore, the feedforward compensation calculation module can obtain the rate of change of lumen pressure for feedforward compensation calculation while suppressing high-frequency noise.

[0052] S302, after acquiring the pressure fluctuation trend, the feedforward compensation calculation module constructs a local aerodynamic sensitivity model based on the fluid dynamic characteristics inside the flow control valve to quantify the mutual influence of physical parameter changes on gas flow. According to the aforementioned compressible fluid valve flow equation, the feedforward compensation calculation module performs partial derivative calculations for the intermediate cavity pressure signal and the valve mechanical opening, respectively. Through this partial derivative calculation, the feedforward compensation calculation module obtains the control valve aerodynamic pressure sensitivity and control valve mechanical displacement sensitivity as local aerodynamic sensitivity parameters. Combining the extracted cavity pressure change rate and the control valve aerodynamic pressure sensitivity, the feedforward compensation calculation module can multiply and calculate the transient mass flow deviation caused by pressure disturbance.

[0053] S303, after obtaining the aforementioned local pneumatic sensitivity parameters and transient mass flow rate deviation, the feedforward compensation calculation module further evaluates the hysteresis characteristics of the flow control valve's physical action. Typically, the flow control valve is driven by a pneumatic diaphragm or hydraulic actuator, and its physical valve stem displacement has an inherent time delay in response to control commands. To compensate for the flow rate deviation caused by pressure disturbances during this delay, the feedforward compensation calculation module introduces the actuator's mechanical delay time constant. After completing data validity verification, the feedforward compensation calculation module uses a feedforward compensation conversion formula to convert the transient mass flow rate deviation into a dynamic feedforward compensation amount. The feedforward compensation conversion formula is as follows: ; in, This represents the dynamic feedforward compensation amount. Indicates the mechanical displacement sensitivity of the control valve. This indicates the pneumatic pressure sensitivity of the control valve. Indicates the rate of change of pressure in the lumen. This represents the mechanical delay time constant of the actuator; This represents the negative displacement conversion coefficient. This represents the rate of change in mass flow rate caused by changes in pressure within the intermediate tube. This indicates the transient mass flow rate deviation (i.e., the equivalent transient mass flow rate deviation formed during the mechanical delay time of the actuator).

[0054] Through the calculation using this feedforward compensation conversion formula, the feedforward compensation calculation module converts the previous aerodynamic pressure disturbance into an equivalent advanced valve displacement compensation command. The calculated dynamic feedforward compensation amount represents the advance action margin required to match the aforementioned steady-state basic opening command, and is used to transmit it to the subsequent command synthesis logic to participate in the generation of the final output.

[0055] For step S4, which involves determining the polarity of the dynamic feedforward compensation and generating an asymmetric excitation pulse signal, and then superimposing the asymmetric excitation pulse signal, the dynamic feedforward compensation, and the steady-state basic opening command to generate the final control command and send it to the control valve servo positioner, the command synthesis excitation module inside the control device performs the following sub-step operations.

[0056] S401, during system operation, the command synthesis excitation module receives the dynamic feedforward compensation amount output previously. Due to the inherent mechanical static friction of the valve stem packing and sealing components inside the flow control valve, when the control command changes direction, the valve often needs to overcome the static friction to generate displacement again. This physical hysteresis phenomenon creates an opening response dead zone in the system. At the engineering implementation level, when it is detected that the dynamic feedforward compensation amount of the current calculation cycle and the dynamic feedforward compensation amount of the previous calculation cycle have opposite polarities, and the absolute value of the current dynamic feedforward compensation amount is not greater than the system's preset opening dead zone judgment threshold, the command synthesis excitation module determines that the flow control valve is at risk of entering the mechanical static friction opening dead zone and triggers the high-frequency excitation logic for escape. As a preferred method, this opening dead zone judgment threshold is based on a comprehensive judgment of the historical operating data of the gas turbine TCS (Turbine Control System) system and the factory hysteresis test curve of the flow control valve, and is generally set to 0.5% to 1.5%.

[0057] S402, when the system is determined to have a risk of mechanical static friction dead zone, the instruction synthesis excitation module triggers the high-frequency excitation logic to generate an asymmetric excitation pulse signal. From a physical mechanism perspective, by superimposing a high-frequency micro-amplitude oscillation component onto the low-frequency control signal, the transmission components inside the control valve can maintain a high-frequency micro-amplitude dynamic oscillation state, thereby converting a large static friction force into a smaller dynamic friction force and reducing the starting resistance of the valve action. To match the directionality of the feedforward compensation, the instruction synthesis excitation module uses an asymmetric excitation pulse generation formula to calculate the asymmetric excitation pulse signal. The asymmetric excitation pulse generation formula is: ; in, This represents an asymmetric excitation pulse signal. Indicates the amplitude of the foundation excitation. This represents the asymmetric bias coefficient. This represents the sign discrimination function. This represents the dynamic feedforward compensation amount. Represents the sine operation function. Represents pi (π). Indicates the excitation frequency. Represents a time variable; Indicates the direction of feedforward compensation. Indicates the excitation phase angle; Represents the basic sine wave. Indicates the direction of the current excitation half-cycle. This indicates the dynamic bias of the amplitude. This indicates asymmetric envelope-adjusted gain.

[0058] when When positive, the excitation amplitude of the positive half-cycle is greater than that of the reverse half-cycle; when When the value is negative, the excitation amplitude of the negative half-cycle is greater than that of the positive half-cycle. Through the calculation of this asymmetric excitation pulse generation formula, the instruction synthesis excitation module can adaptively generate an asymmetric excitation pulse signal with a larger amplitude in the current compensation direction and a smaller amplitude in the opposite direction, based on the actual polarity direction of the feedforward compensation. This helps the flow control valve to quickly get out of the friction jamming area.

[0059] S403, after the above-mentioned excitation component calculation, the command synthesis excitation module enters the superposition and synthesis stage of command signals of various orders. The command synthesis excitation module synchronously retrieves the steady-state basic opening command output by the basic opening calculation module, the dynamic feedforward compensation amount output by the feedforward compensation calculation module, and the asymmetric excitation pulse signal generated in real time within this module. The command synthesis excitation module generates the final control command in the digital computation domain using the control command synthesis formula, which is: ; in, Indicates the final control command. This represents a limit function for the range of 0% to 100%. This indicates the steady-state basic opening command. This represents the dynamic feedforward compensation amount. Indicates the dead zone trigger flag. This represents an asymmetric excitation pulse signal; This represents the conditionally triggered excitation component. This indicates a synthetic control command that is not limited in amplitude.

[0060] When the instruction synthesis excitation module determines that there is a risk of mechanical static friction dead zone, ;otherwise, After signal synthesis and limiting, the command synthesis excitation module sends the final control command to the control valve servo positioner via a 4-20mA standard analog signal or a Profibus-DP fieldbus or other industrial general electrical interface. Upon receiving the final control command, the control valve servo positioner converts it into the driving air or hydraulic pressure matching the flow control valve, pushing the valve to move along the expected trajectory, thus completing the closed-loop process of stabilizing the gas turbine fuel flow.

[0061] Specific application examples: To aid in understanding the technical details and actual control effects of the present invention, a specific application embodiment combining F-class heavy-duty gas turbine ignition and low-load conditions is provided below, along with corresponding experimental verification data and effect comparison process.

[0062] During the initial ignition stage of a gas turbine, the gas path system operates under low flow and high pressure differential conditions, which places high demands on the stability of fuel flow control. To verify the effectiveness of the algorithm of this invention in a real physical system, typical transient operating parameters collected on-site were substituted into the control formula for specific numerical calculations, thereby demonstrating the solution process of feedforward compensation and excitation logic.

[0063] This embodiment selects a specific operational transient during the cold start-up and ignition speed phase of the unit. At this time, the control device acquires the first absolute temperature signal through the electrical interface. The first absolute pressure signal is 293.15K. The pressure signal in the intermediate tube is 3.5 MPa. The pressure is 2.0 MPa. Based on the built-in fluid property database, the Joule-Thomson coefficients corresponding to the natural gas components are... It was calibrated to 4.5 K / MPa. The thermodynamic property calculation module called the transient temperature correction formula to restore the thermodynamic state: ; Substituting real-time parameters into the formula, the transient fluid calculation temperature is obtained. Due to the throttling expansion effect, the gas temperature inside the intermediate pipe is 6.75K lower than that upstream. If this correction is not made, it will lead to errors in the fluid density assessment during the basic opening calculation.

[0064] During the concurrent pressure optimization phase, the basic opening calculation module retrieves the basic mapped pressure baseline from the mapping curve based on the target set flow rate. The actual pressure signal of the main pipe was acquired at 2.2 MPa. The specific heat ratio of the gas is 1.2 MPa, obtained by iterative calculation of the AGA8 Standard Model equation. The value is 1.3. This is combined with the accuracy of the field transmitter and the anti-blocking pressure margin. The preset pressure is 0.05 MPa. Substituting this into the formula, the critical blockage pressure is obtained as follows: ; Combined with anti-blocking pressure margin The upper limit of safety for noncritical flow is: ; Therefore, the target pressure is set as follows: ; This value is below the critical blockage pressure and maintains a preset pressure margin with respect to the critical boundary, keeping the flow control valve within the non-critical flow regulation range.

[0065] During dynamic adjustment, pressure pulsations occur in the intermediate pipeline, and the feedforward compensation calculation module extracts the downward pressure trend. Under the definition that an increase in control command corresponds to an increase in valve opening, a pressure drop will lead to a decrease in mass flow rate at the same opening. Therefore, the dynamic feedforward compensation amount calculated by the feedforward compensation calculation module is... +1.5% is used to increase the opening of the flow control valve in advance. To overcome the mechanical dead zone of the valve during minor movements, the instruction synthesis excitation module triggers compensation logic. The basic excitation amplitude is set. The asymmetric bias coefficient is 0.2%. The excitation frequency is 0.5. The frequency is 15Hz. The asymmetric excitation pulse signal is calculated using the asymmetric excitation pulse generation formula related to the feedforward compensation direction: ; In this embodiment, the dynamic feedforward compensation amount corresponding to the pressure drop is +1.5%, and the polarity sign extraction function... The output is +1. Substituting into the asymmetric excitation pulse generation formula, we can see that when... At that time, the excitation amplitude is: ; when At that time, the excitation amplitude is: ; Therefore, when the feedforward compensation direction is the valve opening direction, the excitation amplitude of the valve opening half-cycle is greater than that of the valve closing half-cycle. When the dynamic feedforward compensation is negative, the excitation amplitude of the negative half-cycle increases accordingly, thus aligning the excitation direction with the current compensation direction. This asymmetrical amplitude distribution, after the control command is superimposed, applies a larger thrust in the direction of the desired action and maintains a smaller oscillation in the opposite direction, promoting valve stem disengagement.

[0066] Based on the above embodiments, the following is an exemplary description of the control process using a specific embodiment of fuel flow control under gas turbine ignition conditions.

[0067] Under gas turbine ignition conditions, by reducing Figure 3 The opening degree of the pressure regulating valve in the system can reduce the pressure in front of the control valve. Thus, under the same fuel flow conditions, the control valve can increase its opening degree, thereby improving valve accuracy, better controlling the ignition flow, and increasing the probability of successful gas turbine ignition.

[0068] Specifically, during gas turbine ignition, the required ignition fuel flow rate is determined based on multiple environmental parameters, including ambient pressure, temperature, and humidity. During control, the pressure regulating shut-off valve first opens to a certain degree, ensuring the downstream P2 pressure. This P2 pressure has a linear relationship with the turbine's rotational speed. Based on the current ignition speed and a pre-defined linear relationship formula in the logic, a unique downstream P2 pressure for the pressure regulating valve is obtained. The pressure regulating valve continuously adjusts its opening according to the closed-loop control logic to obtain the P2 pressure based on the rotational speed. The control valve opening is calculated by back-calculating the required valve opening based on its own flow coefficient, the upstream P2 pressure, and the aforementioned required ignition fuel flow rate, thus obtaining the openings of both valves.

[0069] To further verify the system-level control effect, a comparative experiment was conducted using a gas turbine semi-physical simulation test platform.

[0070] A pneumatic simulation model of the gas turbine fuel pipeline system was built in the control test platform, and connected to the control valve servo positioner and actual pneumatic actuator used in the industrial field. The system was configured to steady-state operation mode, and the initial test reference flow rate was set to the ignition rated flow rate.

[0071] The control method of this invention and the conventional control method were deployed in the control system respectively, and run under the same aerodynamic simulation model, the same initial reference flow rate, and the same pressure disturbance boundary conditions to obtain comparative data of the two control methods. The conventional control method uses single closed-loop PID logic and lacks temperature correction, feedforward compensation, and high-frequency excitation modules; the control method of this invention activates the aforementioned dynamic calculation logic.

[0072] When the running time reaches 1 second, a continuous negative pressure disturbance signal is injected into the back pressure boundary on the combustion chamber main pipe side through simulation software to simulate the impact of combustion chamber back pressure reduction on fuel pipeline suction during multi-condition switching. This disturbance is transmitted to the intermediate pipeline via the fuel pipeline aerodynamic model, causing a corresponding change in the intermediate pipeline pressure signal acquired by the second pressure transmitter, thereby triggering the pressure change rate extraction logic of the feedforward compensation calculation module. The command action waveforms generated by the two control methods under this disturbance and the corresponding valve displacement response data are recorded using a high-frequency data acquisition instrument, with the test duration set to 5 seconds.

[0073] Figure 4 The simulation test platform demonstrates the pressure drop boundary conditions injected into the downstream lumen. Figure 4 The black dotted line represents the boundary curve of the lumen pressure disturbance.

[0074] Figure 5 The differences in the trajectories of the output signals of the two control algorithms are shown under pressure disturbance boundaries. Figure 5The dark gray dashed line represents the output command curve of the traditional conventional control method. Figure 5 The solid black line in the middle represents the output command curve of the control method of the present invention.

[0075] Figure 6 It reflects the actual displacement response of the underlying actuator after receiving the corresponding instruction. Figure 6 The dark gray dashed line represents the displacement response curve of the traditional conventional control method. Figure 6 The solid black line in the middle represents the displacement response curve of the control method of the present invention.

[0076] according to Figure 4 The data shows that the boundary pressure in the lumen drops after 1 second. Faced with pressure disturbances, traditional control methods mainly rely on feedback regulation, whose output command lags behind the moment the disturbance occurs, and the rise is relatively gradual. Figure 6 It is evident that the valve displacement response corresponding to traditional conventional control methods exhibits a stepped stagnation in the initial stage, indicating that the valve stem, under minute command changes, is affected by the static friction of the packing and fails to form continuous displacement in a timely manner. This stagnation phenomenon prolongs the time for the system to recover the target flow rate, which can easily lead to flameout in the gas turbine combustion chamber in industrial settings.

[0077] Combination Figure 5 and Figure 6 Data analysis shows that the solid black lines in the figure represent different control trajectories exhibited by the control method of this invention. Relying on the collaborative solution of feedforward compensation and state parameter inversion, the system outputs a compensation feedforward quantity with leading characteristics in the early stages of sensing the pressure change rate. In the initial interval where the command polarity changes, the command synthesis excitation module actively superimposes a high-frequency asymmetric excitation signal onto the basic command. (Observation) Figure 5 As can be seen in the figure, the solid black line represents a regular high-frequency oscillation envelope attached to the output command curve of the control method of the present invention. Driven by this envelope signal, Figure 6 The displacement response curve of the underlying physical valve exhibits a continuous and stable upward trajectory, indicating that the internal transmission components achieve responsiveness to control commands under dynamic friction conditions. Engineering experimental data confirms the effectiveness of the asymmetric excitation pulse generation formula in suppressing the dead zone of mechanical static friction, enabling the gas turbine to establish flow balance with a shorter settling time when facing external disturbances, thus ensuring the aerodynamic stability of the unit under complex operating conditions.

[0078] To implement the above embodiments, this application also proposes an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the heavy-duty gas turbine fuel flow stabilization control method as described in any of the first aspect embodiments above.

[0079] To implement the above embodiments, this application also proposes a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the heavy-duty gas turbine fuel flow stabilization control method as described in any one of the first aspects of the embodiments above.

[0080] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0081] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0082] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0083] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0084] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0085] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0086] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0087] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for stable control of fuel flow in a heavy-duty gas turbine, characterized in that, include: The first absolute pressure signal and the first absolute temperature signal upstream of the pressure regulating shut-off valve, the pressure signal of the intermediate cavity in the intermediate pipeline, and the natural gas component parameters are obtained, and the fluid thermodynamic parameters of natural gas are calculated. Based on the fluid thermodynamic parameters, the intermediate pipe pressure signal, the actual pressure signal of the main pipe inside the combustion chamber main pipe and the target set flow rate, a target set pressure for controlling the pressure regulating shut-off valve is generated, and a steady-state basic opening command for the flow control valve is calculated. The intermediate cavity pressure signal is subjected to time differentiation operation, and the transient mass flow rate deviation is calculated in combination with local aerodynamic sensitivity. The transient mass flow rate deviation is then converted into a dynamic feedforward compensation amount that matches the steady-state basic opening command. The polarity of the dynamic feedforward compensation is determined and an asymmetric excitation pulse signal is generated. The asymmetric excitation pulse signal, the dynamic feedforward compensation, and the steady-state basic opening command are superimposed to generate the final control command, which is then sent to the control valve servo positioner.

2. The method for stable control of fuel flow in a heavy-duty gas turbine according to claim 1, characterized in that, By acquiring the first absolute pressure signal and the first absolute temperature signal upstream of the pressure regulating shut-off valve, the intermediate pipe cavity pressure signal in the intermediate pipeline, and the natural gas component parameters, the fluid thermodynamic parameters of the natural gas are calculated, including: The natural gas component parameters, the first absolute pressure signal, the first absolute temperature signal, and the intermediate pipeline pressure signal are obtained, and the corresponding Joule-Thomson coefficients are retrieved from the built-in fluid property database. The values ​​of the first absolute pressure signal and the intermediate lumen pressure signal are compared. When the first absolute pressure signal is greater than the intermediate cavity pressure signal, the transient temperature correction formula is used to calculate the transient fluid calculation temperature using the first absolute pressure signal, the first absolute temperature signal, the intermediate cavity pressure signal, and the Joule-Thomson coefficient, thereby obtaining the transient fluid calculation temperature after compensating for the throttling effect.

3. The method for stable control of fuel flow in a heavy-duty gas turbine according to claim 2, characterized in that, The calculations yielded the fluid thermodynamic parameters of natural gas, including: The transient fluid calculation temperature, the intermediate pipe pressure signal, and the natural gas component parameters are used as input boundary conditions and substituted into the real gas state equation of natural gas to obtain the dynamic compressibility factor and specific heat ratio of natural gas. The fluid thermodynamic parameters are composed of the transient fluid temperature, the natural gas dynamic compressibility factor, and the gas specific heat ratio.

4. The method for stable control of fuel flow in a heavy-duty gas turbine according to claim 3, characterized in that, Based on the fluid thermodynamic parameters, the intermediate pipe pressure signal, the actual pressure signal inside the combustion chamber main pipe, and the target set flow rate, a target set pressure for controlling the pressure regulating shut-off valve is generated, including: The target set flow rate is obtained, and a table lookup or interpolation calculation is performed based on the pre-calibrated correspondence between the target set flow rate and the target pressure of the intermediate pipeline to output the corresponding basic mapping pressure benchmark. Using the anti-blocking limiting constraint formula, the critical blockage pressure is calculated by utilizing the actual pressure signal of the main pipe and the gas specific heat ratio in the fluid thermodynamic parameters. Based on the system's preset anti-blocking pressure margin, boundary constraint optimization calculations are performed on the basic mapped pressure benchmark and the critical blockage occurrence pressure to generate the target set pressure; The target set pressure is compared with the intermediate cavity pressure signal to generate a pressure regulating opening command to control the pressure regulating shut-off valve.

5. The method for stable control of fuel flow in a heavy-duty gas turbine according to claim 1, characterized in that, Based on the fluid thermodynamic parameters, the intermediate pipe pressure signal, the actual pressure signal of the main pipe inside the combustion chamber, and the target set flow rate, a steady-state basic opening command for the flow control valve is calculated, including: Read the target set flow rate, the intermediate tube pressure signal, the main tube actual pressure signal and the fluid thermodynamic parameters, substitute them into the compressible fluid valve flow equation, and solve the valve flow capacity coefficient in reverse; The inherent flow characteristic curve of the flow control valve is invoked, and the valve flow capacity coefficient is converted into the corresponding physical valve stroke percentage to generate the steady-state basic opening command for the flow control valve.

6. The method for stable control of fuel flow in a heavy-duty gas turbine according to claim 1, characterized in that, Perform time differentiation on the intermediate lumen pressure signal, including: The pressure signal of the intermediate cavity is acquired, and a first-order low-pass digital filter is used to perform filtering at the differential operation front end; The time differentiation operation is performed on the filtered intermediate cavity pressure signal to extract the cavity pressure change rate used for feedforward compensation calculation.

7. The method for stable control of fuel flow in a heavy-duty gas turbine according to claim 6, characterized in that, The transient mass flow rate deviation is calculated by combining local aerodynamic sensitivity, and the transient mass flow rate deviation is converted into a dynamic feedforward compensation amount to match the steady-state basic opening command, including: Based on the flow equation of compressible fluid valve, partial derivatives are calculated for the intermediate cavity pressure signal and valve mechanical opening respectively to obtain the control valve pneumatic pressure sensitivity and control valve mechanical displacement sensitivity as local pneumatic sensitivity parameters. By multiplying the extracted rate of change of the cavity pressure with the pneumatic pressure sensitivity of the control valve, the transient mass flow rate deviation caused by the pressure disturbance is calculated; By introducing the mechanical delay time constant of the actuator and using a feedforward compensation conversion formula, the transient mass flow deviation is converted into the dynamic feedforward compensation amount, which represents the advance action margin required to match the steady-state basic opening command.

8. The method for stable control of fuel flow in a heavy-duty gas turbine according to claim 1, characterized in that, Determining the polarity of the dynamic feedforward compensation and generating an asymmetric excitation pulse signal includes: The system receives the dynamic feedforward compensation amount. When it is detected that the dynamic feedforward compensation amount of the current operation cycle and the dynamic feedforward compensation amount of the previous operation cycle satisfy the opposite polarity relationship, and the absolute value of the current dynamic feedforward compensation amount is not greater than the system's preset opening dead zone judgment threshold, it determines that there is a mechanical static friction opening dead zone risk and triggers the high-frequency excitation logic for getting out of trouble. When the high-frequency excitation logic for escaping the trap is triggered, an asymmetric excitation pulse generation formula related to the feedforward compensation direction is used to adaptively generate the asymmetric excitation pulse signal according to the actual polarity direction of the dynamic feedforward compensation amount.

9. A heavy-duty gas turbine fuel flow stabilization control device, characterized in that, A method for stabilizing fuel flow in a heavy-duty gas turbine, applicable to any one of claims 1-8, comprises: The thermophysical property calculation module is used to acquire the first absolute pressure signal, the first absolute temperature signal, the intermediate pipeline pressure signal, and the natural gas component parameters, and to calculate the fluid thermodynamic parameters of the natural gas. The basic opening calculation module is used to receive the fluid thermodynamic parameters, and combine the intermediate pipe cavity pressure signal, the main pipe actual pressure signal and the target set flow rate to generate the target set pressure of the intermediate pipe to control the pressure regulating shut-off valve. At the same time, it calculates the steady-state basic opening command of the flow control valve. The feedforward compensation calculation module is used to perform differential operations on the intermediate cavity pressure signal to obtain the cavity pressure change rate, and then calculate the transient mass flow rate deviation, and convert the transient mass flow rate deviation into a dynamic feedforward compensation amount that matches the steady-state basic opening command; The instruction synthesis excitation module is used to integrate the steady-state basic opening instruction with the dynamic feedforward compensation amount, and combine it with the generated asymmetric excitation pulse signal to generate the final control instruction, and send the final control instruction to the control valve servo positioner.

10. A heavy-duty gas turbine fuel flow stabilization control device according to claim 9, characterized in that, The instruction synthesis excitation module is used to generate an asymmetric excitation pulse signal, and to superimpose the asymmetric excitation pulse signal, the steady-state foundation opening command, and the dynamic feedforward compensation amount to generate a final control command. Specifically, the instruction synthesis excitation module is used for: Determine whether the flow control valve is at risk of entering the mechanical static friction dead zone; When there is a risk of a dead zone in the mechanical static friction opening, the dead zone trigger flag takes effect, generating the asymmetric excitation pulse signal. In the digital computing domain, the steady-state basic opening command, the dynamic feedforward compensation amount, and the asymmetric excitation pulse signal are superimposed in the time domain to generate the final control command.

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