Anti-surge control method for combustion-driven compressor unit based on decoupling active disturbance rejection control

Abstract

The invention discloses an anti-surge control method for a combustion-driven compressor unit based on decoupling active disturbance rejection control. The anti-surge control method comprises the following steps: deducing a simplified dimensionless coordinate system; historical records of the following variables under different rotating speed working conditions are read; s100, fitting the obtained historical data under the same working condition according to a fitting formula of a stable region and an unstable region to obtain critical surge points, putting the critical surge points into the dimensionless coordinate system obtained in the step S100 through coordinate transformation, and drawing a surge line SLL; drawing a surge control line SCL according to the obtained surge line SLL; calculating the obtained distance between the surge control line SCL and the abscissa of the current operating point of the unit in the dimensionless coordinate system; designing an active disturbance rejection controller based on an error form based on the obtained distance; and designing a decoupling loop and applying the obtained active disturbance rejection controller to the decoupling loop. According to the invention, the mutual interference between anti-surge control and rotating speed control can be effectively eliminated, and the damage to the production process caused by the surge phenomenon is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel-driven compressors, and more specifically, to a fuel-driven compressor unit anti-surge control method based on decoupling self-disturbance rejection control. Background Art

[0002] Surge is a vibration that occurs in the compressor under abnormal conditions when the flow rate is reduced to a certain level. It is very harmful to the compressor. In order to ensure the economic benefits and safe operation of the unit, anti-surge control is required. There are many anti-surge control solutions. Currently, the PID controller is the most commonly used. However, the control accuracy of the PID controller is limited and the anti-interference performance is average. In order to meet the control needs, complex cascade control loops are often used to enhance the anti-interference ability, which brings higher costs. At present, many advanced control technologies have emerged and achieved good results in compressor anti-surge control, such as fuzzy control (Wu Qinglong, Yang He, Zhao Baiyang, et al. Research on automatic control technology of centrifugal compressor anti-surge [J]. Petroleum and Chemical Equipment, 2023, 26 (09): 19-21.), radial basis function neural network adaptive control (San He, Mengyu Xie, Patioon Tontiwachwuthikul, et al. Self-adapting anti-surge intelligence control and numerical simulation of centrifugal compressors based on RBF neural network [J]. Energy Reports, 2022, 8: 2434-2447.), etc. Active disturbance rejection control has high anti-disturbance performance and is easy to implement, and has good industrial application prospects. Among them, the error-based active disturbance rejection control (Error-based Active Disturbance Rejection Control, EADRC) by R. Madonski et al. has a new plug-and-play structure and has better application value than general active disturbance rejection control.

[0003] In the compressor anti-surge control system, the working flow of the compressor is usually controlled at a safe level. In the fuel-driven compressor unit, the operating state of the compressor depends on the speed of the turbine. When the compressor runs to the surge control line, the surge control opens the anti-surge valve for adjustment. At this time, if the adjustment direction of the performance control is to reduce the speed of the compressor or close the inlet guide vane opening, this will make the compressor more prone to surge, thus forming interference with the surge control. When the control tasks of the two are combined, the instability of the surge condition greatly limits the working range of the compressor system. If the coordinated control measures are not designed properly, when the compressor operating point moves from the stable area to the surge area, a strong coupling effect will appear between the flow control and the pressure control.

[0004] In summary, there is an urgent need for an anti-surge control method that can simultaneously solve the anti-disturbance problem in anti-surge control and the coupling problem between flow control and pressure control. Summary of the invention

[0005] In order to overcome the problem that the above-mentioned prior art anti-surge control methods lack the means to simultaneously solve the anti-disturbance problem in anti-surge control and the coupling problem between flow control and pressure control, the present invention provides an anti-surge control method for a fuel-driven compressor unit based on decoupled self-anti-disturbance control.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for anti-surge control of a fuel-driven compressor unit based on decoupling auto-disturbance rejection control, comprising the following steps:

[0007] S100: According to the compressor inlet pressure P s , flow element differential pressure ΔP os and the compressor outlet pressure P d Derive simplified dimensionless coordinate systems;

[0008] S200: Read the historical records of the following variables under different speed conditions, including: compressor inlet pressure P s , compressor outlet pressure P d , compressor inlet temperature T s , compressor outlet temperature T d And the flow element differential pressure ΔP os ;

[0009] S300: fitting the historical data under the same working condition obtained in step S200 according to the fitting formula of the stable region and the unstable region to obtain the critical surge point, placing each critical surge point in the dimensionless coordinate system obtained in step S100 after coordinate transformation, and drawing the surge line SLL;

[0010] S400: Draw a surge control line SCL according to the surge line SLL obtained in step S300;

[0011] S500: Calculating the distance between the surge control line SCL obtained in step S400 and the horizontal coordinate of the current operating point of the unit in the dimensionless coordinate system;

[0012] S600: Designing an error-based active disturbance rejection controller based on the distance obtained in step S500;

[0013] S700: Design a decoupling loop and apply the active disturbance rejection controller obtained in step S600 to the decoupling loop.

[0014] Preferably, step S100 specifically includes the following steps:

[0015] S101: Derived from the polytropic pressure head formula and the inlet flow square formula:

[0016] Polytropic head formula:

[0017]

[0018] Among them, H p is the variable pressure head, Z avg is the average of the compressor inlet and outlet flow factors, R is the compressor outlet compression factor, R c is the compressor inlet and outlet pressure ratio;

[0019] Inlet flow square formula:

[0020]

[0021] Among them, Q S 2 represents the square of the inlet flow, Z s represents the compressor inlet flow factor;

[0022] S102: Comparing formula (1) and (2), due to Z s With Z avg Equal, R and T S It is the common part of the two equations. Eliminate the common part of the two equations and get the simplified flow square q on the horizontal axis s 2 The formula is as follows:

[0023]

[0024] After eliminating the common part of the multi-variable pressure head, the pressure head h is simplified p :

[0025]

[0026] S103: Therefore, the simplified flow square and the simplified pressure head together constitute the horizontal and vertical coordinates of the dimensionless coordinate system.

[0027] Preferably, in step S300, the compressor characteristic curve is fitted and the surge line SLL is obtained according to the following calculation method:

[0028] The compressor characteristic approximation equation is fitted using historical data measurements in the stable area. The characteristic curve of the compressor in the stable area is fitted by a cubic polynomial, and the formula is as follows:

[0029]

[0030] Among them, q s is the inlet flow rate, R c is the dimensionless pressure ratio, R c (0), H and W are the parameters that need to be fitted, which are calculated based on the pressure ratio and the flow rate corresponding to the surge point;

[0031] In the unstable region, the approximate stability characteristic equation is fitted with a simpler quadratic polynomial:

[0032]

[0033] The fitted quadratic polynomial and cubic polynomial have an intersection point. The cubic polynomial side of the intersection point is the stable zone characteristic curve, and the quadratic polynomial side of the intersection point is the stable zone characteristic curve. The intersection point of the curves is called the critical surge point.

[0034] Preferably, in step S300, since the above formulas (5) and (6) are mass flow rate q s With pressure ratio R c The relationship between them is transformed into coordinates, and q s becomes q s 2 , the pressure ratio R c According to formula (4), it is converted into the simplified pressure head h p .

[0035] Preferably, in step S400, the surge control line SCL is not a fixed straight line, but migrates according to the following calculation method as surge occurs: in order to leave a certain margin for the unit, the surge line SLL needs to be translated to the right by a certain distance in the dimensionless coordinate system to obtain a surge control line SCL that is independent of the compressor operating conditions.

[0036] Preferably, in step S400, during the control process, the state of the fuel-driven compressor set is controlled between the two, and each time surge occurs, SCL should be moved again to obtain a larger margin. Therefore, the mathematical model of SCL is as follows:

[0037]

[0038] Among them, k is the slope of SCL, which is equal to the slope of SLL in the same ordinate interval. λ0 corresponds to the initial abscissa intercept, representing the initial margin. The parameter n is the number of surges, λ is the distance to move to the right each time a surge occurs. The mathematical model of SCL can be built in the control system and can be operated on the HMI screen to change the position of SCL according to needs.

[0039] Preferably, in step S500, the current operating parameters of the unit are detected, the coordinates (a, b) of the current unit operating point are found, and the distance between the horizontal coordinate and the surge control line SCL is calculated, which is represented by μ. The distance between the unit operating point and the surge control line is obtained by the following calculation method:

[0040] μ=af(b) (8)

[0041] Among them, f(b) is the horizontal coordinate value obtained by substituting the simplified pressure head of the unit at this time into the SCL calculation.

[0042] Preferably, in order to meet the needs of the site, an error-based EADRC is used. The input of the EADRC controller is the distance calculated in step S500, and the output is the valve opening of the anti-surge control valve. When the working point enters the left area of ​​the surge control line, the anti-surge control valve is opened to increase the flow entering the compressor to meet the anti-surge demand. The EADRC model order is 2, and it is assumed that the total derivable disturbance to be estimated is f * , the error of the input model is second-order differentiable, then the state equation can be written as:

[0043]

[0044] Among them, x is the state vector, which is used to observe the error and disturbance, that is, The superscript of the variable in the formula represents that the variable is an observed variable, and the dot represents the differential of the variable;

[0045] Based on this, the ESO model is constructed:

[0046]

[0047] in, is the state variable observation, l T =[l1l2 l3] is the observer gain vector to be selected;

[0048] The control rate design is shown in formula (11):

[0049]

[0050] In general, li (i=1,2,3) and k i The value of (i=0,1) and parameter ω o ,ω c The value is shown in formula (12):

[0051]

[0052] Therefore, the parameters of the anti-surge controller are finally determined by ω o ,ω c , b0 and three parameters need to be adjusted.

[0053] Preferably, in step S700, the design purpose is to eliminate the mutual interference between the anti-surge control and the speed control in the fuel-driven compressor unit. The active disturbance rejection controller in step S600 is used as the anti-surge controller in the design. The formula of the decoupling loop is shown in formula (13):

[0054]

[0055] Among them, G 12 (s) represents the impact of the anti-surge controller on the performance controller, G1(s) represents the proportional gain of the channel, and T1 represents the time constant of the inertia link of the channel; G 21 (s) represents the effect of the performance controller on the anti-surge controller, G2(s) represents the proportional gain of the channel, and T2 represents the time constant of the inertia link of the channel.

[0056] Preferably, the order of step S100 and step S200 can be swapped.

[0057] Compared with the prior art, the beneficial effects of the present invention are as follows: when the present invention controls the actual fuel-driven compressor unit in the industrial field, the flow rate and the compression ratio are converted to obtain the corresponding dimensionless data, and the error-based self-disturbance control controller is used to control the compressor against surge, which can respond to the real-time status of the compressor faster and more quickly; and the error-based self-disturbance control controller is a special type of self-disturbance control that uses error as input. Compared with other self-disturbance control, it does not rely on the precise model of the object, is plug-and-play, has high accuracy and strong anti-disturbance ability. A decoupling control loop with a delay link is designed to effectively eliminate the mutual interference between the anti-surge control and the speed control, prevent the harm of the surge phenomenon to the production process, and provide a reference for the anti-surge control of fuel-driven compressor units in industrial fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is an implementation flow chart of the anti-surge control method of a fuel-driven compressor unit based on decoupling auto-disturbance rejection control of the present invention;

[0059] Figure 2 A schematic diagram of a surge line obtained by connecting critical surge points of the compressor at different speeds;

[0060] Figure 3 It is a schematic diagram of obtaining a surge control line SCL from a surge line SLL;

[0061] Figure 4 This is a schematic diagram of the decoupling circuit of the fuel-driven compressor unit;

[0062] Figure 5 This is another implementation flow chart of the anti-surge control method for a fuel-driven compressor unit based on decoupled anti-disturbance control of the present invention. DETAILED DESCRIPTION

[0063] The drawings are only for illustrative purposes and cannot be construed as limiting the present invention. To better illustrate the present embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are only for illustrative purposes and cannot be construed as limiting the present invention.

[0064] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "long", "short" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0065] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0066] Example 1

[0067] like Figure 5 As shown, a method for anti-surge control of a fuel-driven compressor unit based on decoupling anti-disturbance control is characterized by comprising the following steps:

[0068] S100: According to the compressor inlet pressure P s , flow element differential pressure ΔP os and the compressor outlet pressure P d Derive simplified dimensionless coordinate systems;

[0069] S200: Read the historical records of the following variables under different speed conditions, including: compressor inlet pressure P s , compressor outlet pressure P d , compressor inlet temperature T s , compressor outlet temperature T d And the flow element differential pressure ΔP os ;

[0070] S300: fitting the historical data under the same working condition obtained in step S200 according to the fitting formula of the stable region and the unstable region to obtain the critical surge point, placing each critical surge point in the dimensionless coordinate system obtained in step S100 after coordinate transformation, and drawing the surge line SLL;

[0071] S400: Draw a surge control line SCL according to the surge line SLL obtained in step S300;

[0072] S500: Calculating the distance between the surge control line SCL obtained in step S400 and the horizontal coordinate of the current operating point of the unit in the dimensionless coordinate system;

[0073] S600: Designing an error-based active disturbance rejection controller based on the distance obtained in step S500;

[0074] S700: Design a decoupling loop and apply the active disturbance rejection controller obtained in step S600 to the decoupling loop.

[0075] Example 2

[0076] like Figure 1 As shown, step one: derive a simplified dimensionless coordinate system: For the same compressor, if the inlet operating conditions (machine Mach number, inlet reference flow, flowmeter detection coefficient) change, then the operating conditions of the entire unit will change significantly. Therefore, the present invention will establish a coordinate system with the simplified pressure head as the vertical coordinate, and the influence of these operating conditions can be ignored. Establish a reference system with the square of the inlet flow as the horizontal coordinate and the simplified pressure head as the vertical coordinate, but because the horizontal coordinate is difficult to represent, consider simplifying it to obtain a simplified dimensionless coordinate system. In order to eliminate the influence of changes in gas composition and inlet conditions on the surge line, first, derive according to the multivariable pressure head formula and the inlet flow square formula:

[0077] Polytropic head formula:

[0078]

[0079] Among them, H p Represents variable pressure head, Z avg Represents the average of the compressor inlet and outlet flow factors, R is the compressor outlet compression factor, T Sis the compressor inlet temperature, T d is the compressor outlet temperature, P S is the compressor inlet pressure, P d is the compressor inlet temperature, R c is the compressor inlet and outlet pressure ratio

[0080] Inlet flow square formula:

[0081]

[0082] Among them, Q S 2 represents the square of the inlet flow, Z s Represents the compressor inlet flow factor, ΔP os Represents the compressor inlet flow orifice differential pressure.

[0083] Compared with formula (1) and (2), in general, Z s With Z avg Basically equal, R and T S It is the common part of the two equations. Eliminate the common part of the two equations, and the resulting horizontal coordinate is the simplified flow square q s 2 The formula is as follows:

[0084]

[0085] After eliminating the common part of the multi-variable pressure head, the pressure head h is simplified p :

[0086]

[0087] Therefore, the simplified flow square and the simplified pressure head together constitute the horizontal and vertical coordinates of the dimensionless coordinate system.

[0088] Step 2: Read the historical records of the following variables, including: compressor inlet pressure P s , compressor outlet pressure P d , compressor inlet temperature T s , compressor outlet temperature T d , flow element differential pressure ΔP os .

[0089] Step 3: Calculate the critical surge point and draw the surge line SLL;

[0090] The compressor characteristic curve is generally provided by the manufacturer, and the surge line can be directly drawn in a dimensionless coordinate system based on the existing characteristic curve. However, when the compressor has been in operation for a long time, the characteristic curve may change, or under laboratory conditions, the lack of a compressor characteristic curve will make the experiment difficult to carry out. Therefore, a fitting method is proposed, which requires the use of historical data read in step 2, in which the stable region uses a cubic polynomial, and the formula is as follows:

[0091]

[0092] Among them, q s is the dimensionless mass flow rate, R c is the dimensionless pressure ratio, R c (0), H and W are the parameters that need to be fitted, which are calculated based on the pressure ratio and the flow rate corresponding to the surge point.

[0093] The characteristic curve of the compressor in the stable region is fitted by a cubic polynomial, while the approximate stable characteristic equation in the unstable region is fitted by a simpler quadratic polynomial:

[0094]

[0095] The fitted quadratic polynomial and cubic polynomial will have an intersection point. The cubic polynomial side of the intersection point is the stable zone characteristic curve, and the quadratic polynomial side of the intersection point is the stable zone characteristic curve. The intersection point of the curves is called the critical surge point.

[0096] Note that formulas (5) and (6) are mass flow rates q s With pressure ratio R c The relationship between them needs to be transformed into coordinates. s becomes q s 2 , the pressure ratio R c According to formula (4), it is converted into the simplified pressure head h p .

[0097] The compressor inlet pressure P under different speed conditions collected in step 2 s , compressor outlet pressure P d , compressor inlet temperature T s , compressor outlet temperature T d , flow element differential pressure ΔP os The data are calculated in this way to obtain the critical surge points under different speed conditions. These points are connected on the dimensionless coordinate system to obtain a line. When the compressor runs on the left side of the line, surge is likely to occur. When it runs on the right side, the system works normally. Therefore, it is named the surge line SLL. Figure 2 As shown;

[0098] Step 4: Draw the surge control line SCL;

[0099] In order to leave a certain margin for the unit, the surge line SLL needs to be translated to the right by a certain distance in the dimensionless coordinate system to obtain a surge control line SCL that is independent of the compressor operating conditions. During the control process, the state of the fuel-driven compressor unit is controlled between the two, and each time a surge occurs, the surge control line should be moved again to obtain a larger margin. Therefore, the mathematical model of SCL is as follows:

[0100]

[0101] Among them, k is the slope of SCL, which is equal to the slope of SLL in the same ordinate interval, λ0 corresponds to the initial abscissa intercept, representing the initial margin, parameter n is the number of surges, λ is the distance that SCL needs to move to the right each time surge occurs, and the mathematical model of SCL will be built in the control system and can be operated on the HMI screen to change the position of SCL according to needs. The process of obtaining SCL from SLL is as follows: Figure 3 As shown;

[0102] Step 5: The distance between the current operating point of the computer group and the surge control line SCL;

[0103] Detect the current operating parameters of the unit, find the coordinates of the current unit operating point (a, b), and calculate the distance between the horizontal coordinate and the surge control line SCL, expressed in μ.

[0104] μ=af(b) (8)

[0105] Among them, f(b) is the abscissa value obtained by substituting the simplified pressure head of the unit at this time into the SCL calculation;

[0106] Step 6: Design an ADRC controller based on the error form;

[0107] In order to meet the needs of the site, error-based active disturbance rejection control (EADRC) is adopted.

[0108] The input of EADRC is μ calculated in step 5, and the output is the valve opening of the anti-surge control valve. When the operating point enters the left area of ​​the surge control line, the anti-surge control valve is opened to make the inlet flow meet the requirements. The order of the EADRC model used is 2, and it is assumed that the total derivable disturbance to be estimated is f * , the error of the input model is second-order differentiable, then the state equation can be written as:

[0109]

[0110] Among them, x is the state vector, which is used to observe the error and disturbance, that is, The superscript of the variable in the formula represents that the variable is an observed variable, and the dot represents the differential of the variable.

[0111] Based on this, the ESO model is constructed:

[0112]

[0113] in, is the state variable observation, l T =[l1l2 l3] is the observer gain vector to be selected.

[0114] The control rate design is shown in (11).

[0115]

[0116] In general, l i (i=1,2,3) and k i The value of (i=0,1) and parameter ω o ,ω c The value is shown in formula (12).

[0117]

[0118] Therefore, the parameters of the anti-surge controller are finally determined by ω o ,ω c , b0 and three parameters need to be adjusted.

[0119] Step 7: Design the decoupling circuit.

[0120] The decoupling loop designed in this patent aims to eliminate the mutual interference between the anti-surge control and the performance control in the fuel-driven compressor unit. Without adding the decoupling loop, when the compressor inlet flow rate decreases, the system operating condition is close to the surge line SLL and farther from SCL. According to formula (8), the error value of the input EADRC increases, so the anti-surge control valve opening increases to increase the inlet flow rate. However, when the inlet flow rate increases, the compressor outlet pressure increases accordingly. The pressure controller of the fuel-driven compressor unit closes the gas turbine inlet valve through the actuator, which leads to a decrease in the gas turbine speed setting value, affecting the system performance; at the same time, if the performance controller is adjusted in the direction of increasing the speed, it will also cause the compressor inlet flow rate to decrease, making the system more prone to surge.

[0121] Therefore, it is considered to decouple the anti-surge control loop of the fuel-driven compressor unit from the performance control loop. Considering that the system itself has time delay and the linear superposition effect is limited, a unit forward transfer link is connected in parallel with a negative first-order inertia link, and then the decoupling method is adopted through the amplification link.

[0122] The formula of the decoupling loop is shown in equation (13).

[0123]

[0124] Among them, G 12 (s) represents the impact of the anti-surge controller on the performance controller, G1(s) represents the proportional gain of the channel, and T1 represents the time constant of the inertia link of the channel; G 21 (s) represents the influence of the performance controller on the anti-surge controller, G2(s) represents the proportional gain of the channel, and T2 represents the time constant of the inertia link of the channel.

[0125] The final decoupling circuit is as follows: Figure 4 As shown in the figure, when the inlet flow rate decreases, the output of EADRC increases, increasing the anti-surge valve opening. This effect first increases the control effect of the performance controller through the unit forward transfer link, suppressing the performance degradation trend caused by the increase in the anti-surge valve opening, and due to the existence of the negative first-order inertia link, after a period of time, the effect of EADRC on performance control will gradually disappear, and the effect of the performance regulator will gradually recover. Similarly, the negative impact of the performance control loop on the anti-surge control loop is also suppressed.

[0126] Embodiment 3

[0127] The difference from the first embodiment or the second embodiment is that in this embodiment, the order of step S100 and step S200 can be swapped or the order of step one and step two can be swapped.

[0128] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for anti-surge control of a fuel-driven compressor unit based on decoupling auto-disturbance rejection control, characterized in that: The following steps are involved: S100: According to the compressor inlet pressure P s , flow element differential pressure ΔP os and the compressor outlet pressure P d Derive simplified dimensionless coordinate systems; S2 00： Read the historical records of the following variables under different speed conditions, including: compressor inlet pressure P s , compressor outlet pressure P d , compressor inlet temperature T s , compressor outlet temperature T d And the flow element differential pressure ΔP os ; S300: fitting the historical data under the same working condition obtained in step S200 according to the fitting formula of the stable region and the unstable region to obtain the critical surge point, placing each critical surge point in the dimensionless coordinate system obtained in step S100 after coordinate transformation, and drawing the surge line SLL; S400: Draw a surge control line SCL according to the surge line SLL obtained in step S300; S5 00: Calculate the distance between the surge control line SCL obtained in step S400 and the horizontal coordinate of the current operating point of the unit in the dimensionless coordinate system; S600: Designing an error-based active disturbance rejection controller based on the distance obtained in step S500; S700: Design a decoupling loop and apply the active disturbance rejection controller obtained in step S600 to the decoupling loop.

2. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to claim 1 is characterized in that: Step S100 specifically includes the following steps: S101: Derived from the polytropic pressure head formula and the inlet flow square formula: Polytropic head formula: Among them, H p is the variable pressure head, Z avg is the average of the compressor inlet and outlet flow factors, R is the compressor outlet compression factor, R c is the compressor inlet and outlet pressure ratio; Inlet flow square formula: Among them, Q S 2 represents the square of the inlet flow, Z s represents the compressor inlet flow factor; S102: Comparing formula (1) and (2), due to Z s With Z avg Equal, R and T S It is the common part of the two equations. Eliminate the common part of the two equations and get the simplified flow square of the horizontal axis The formula is as follows: After eliminating the common part of the multi-variable pressure head, the pressure head h is simplified p : S103: Therefore, the simplified flow square and the simplified pressure head together constitute the horizontal and vertical coordinates of the dimensionless coordinate system.

3. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to claim 2 is characterized in that: In step S300, the compressor characteristic curve is fitted according to the following calculation method to obtain the surge line SLL: The compressor characteristic approximation equation is fitted using historical data measurements in the stable area. The characteristic curve of the compressor in the stable area is fitted by a cubic polynomial, and the formula is as follows: Among them, q s is the inlet flow rate, R c is the dimensionless pressure ratio, R c (0), H and W are the parameters that need to be fitted, which are calculated based on the pressure ratio and the flow rate corresponding to the surge point; In the unstable region, the approximate stability characteristic equation is fitted with a simpler quadratic polynomial: The fitted quadratic polynomial and cubic polynomial have an intersection point. The cubic polynomial side of the intersection point is the stable zone characteristic curve, and the quadratic polynomial side of the intersection point is the stable zone characteristic curve. The intersection point of the curves is called the critical surge point.

4. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to claim 3 is characterized in that: In step S300, since the above formulas (5) and (6) are mass flow rate q s With pressure ratio R c The relationship between them is transformed into coordinates, and q s becomes q s 2 , the pressure ratio R c According to formula (4), it is converted into the simplified pressure head h p .

5. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to claim 1 is characterized in that: In the step S400, the surge control line SCL is not a fixed straight line, but moves according to the following calculation method as surge occurs: in order to leave a certain margin for the unit, the surge line SLL needs to be translated to the right by a certain distance in the dimensionless coordinate system to obtain a surge control line SCL that is independent of the compressor operating conditions.

6. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to claim 5 is characterized in that: In step S400, during the control process, the state of the fuel-driven compressor unit is controlled between the two, and each time surge occurs, SCL should be moved again to obtain a larger margin. Therefore, the mathematical model of SCL is as follows: Among them, k is the slope of SCL, which is equal to the slope of SLL in the same ordinate interval. λ0 corresponds to the initial abscissa intercept, representing the initial margin. The parameter n is the number of surges, λ is the distance to move to the right each time a surge occurs. The mathematical model of SCL can be built in the control system and can be operated on the HMI screen to change the position of SCL according to needs.

7. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to claim 1 is characterized in that: In step S500, the current operating parameters of the unit are detected, the coordinates (a, b) of the current unit operating point are found, and the distance between the horizontal coordinate and the surge control line SCL is calculated, which is represented by μ. The distance between the unit operating point and the surge control line is obtained by the following calculation method: μ=af(b) (8) Among them, f(b) is the horizontal coordinate value obtained by substituting the simplified pressure head of the unit at this time into the SCL calculation.

8. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to claim 1, characterized in that: In order to meet the needs of the site, the error-based EADRC is adopted. The input of the EADRC controller is the distance calculated in step S500, and the output is the valve opening of the anti-surge control valve. When the working point enters the left area of ​​the surge control line, the anti-surge control valve is opened to increase the flow entering the compressor to meet the anti-surge demand. The EADRC model order is 2, and it is assumed that the total derivable disturbance to be estimated is f * , the error of the input model is second-order differentiable, then the state equation can be written as: Among them, x is the state vector, which is used to observe the error and disturbance, that is, The superscript of the variable in the formula represents that the variable is an observed variable, and the dot represents the differential of the variable; Based on this, the ESO model is constructed: in, is the state variable observation, l T =[l1l2 l3] is the observer gain vector to be selected; The control rate design is shown in formula (11): In general, l i (i=1,2,3) and k i The value of (i=0,1) and parameter ω o ,ω c The value is shown in formula (12): Therefore, the parameters of the anti-surge controller are finally determined by ω o ,ω c , b0 and three parameters need to be adjusted.

9. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to claim 1, characterized in that: In step S700, the design purpose is to eliminate the mutual interference between the anti-surge control and the speed control in the fuel-driven compressor unit. The anti-disturbance controller in step S600 is used as the anti-surge controller in the design. The formula of the decoupling loop is shown in formula (13): Among them, G 12 (s) represents the impact of the anti-surge controller on the performance controller, G1(s) represents the proportional gain of the channel, and T1 represents the time constant of the inertia link of the channel; G 21 (s) represents the influence of the performance controller on the anti-surge controller, G2(s) represents the proportional gain of the channel, and T2 represents the time constant of the inertia link of the channel.

10. The anti-surge control method for a fuel-driven compressor unit based on decoupling auto-disturbance rejection control according to any one of claims 1 to 9, characterized in that: The order of step S100 and step S200 can be swapped.

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