A control method for reducing steady-state swing of adjustable blade angle at compressor inlet

Abstract

The application belongs to the field of aero-engine control, and particularly relates to a control method for reducing the steady-state swing amount of compressor inlet adjustable blade angle, comprising the following steps: S1, calculating the converted rotating speed N2r25 of the high-pressure rotor 25 section; S2, filtering the converted rotating speed N2r25 to obtain a filtered output value N2r25_1; S3, calculating the expected value a2Dem for controlling the compressor inlet adjustable blade angle a2 based on the filtered output value N2r25_1; and S4, performing closed-loop control on the compressor inlet adjustable blade angle a2 through the expected value a2Dem. The application increases the filtering algorithm on the basis of the current blade angle control instruction design method, so that the a2 control quality swing amount is smaller in the steady state. Meanwhile, the filtering algorithm can adapt to the different control quality requirements in the steady state and the transition state, reduce the a2 control swing amount in the steady state, improve the engine control quality and stability, and will not affect the a2 rapid response performance in the transition state.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aero-engine control, and particularly relates to a control method for reducing the steady-state swing amount of the adjustable blade angle at the compressor inlet. BACKGROUND

[0002] An aero-turbine engine is usually provided with a fan inlet adjustable blade angle a1 and a compressor inlet adjustable blade angle a2, and the engine realizes the requirement of stable margin adjustment by controlling the geometric angles of a1 and a2. If a1 and a2 swing, the aerodynamic stability of the engine will be affected, and therefore, the aero-engine control system needs to reduce the steady-state swing amount of a1 and a2 as much as possible.

[0003] The current steady-state control plan of the adjustable blade angle a2 at the compressor inlet of the aero-engine is determined based on the converted rotating speed N2r25 of the high-pressure rotor 25 of the engine, the expected value a2Dem is calculated as f(N2r25), and then closed-loop control is performed according to the expected value a2Dem.

[0004] The feedback value a2_s of a2 represents the current actual position of the adjustable blade angle. At the steady state of the engine, due to air flow, test, control and other reasons, N2r25 swings to a certain extent, and then the a2Dem calculated according to N2r25 also swings to a certain extent. When the expected value fluctuates, the steady-state swing value of the control result of a2 will undoubtedly increase.

[0005] The present application proposes a filtering method for N2r25, which is used to filter N2r25 at the steady state of the engine, so that a2Dem is more stable, thereby improving the steady-state control quality of the adjustable blade angle at the compressor inlet and reducing the swing amount of a2.

[0006] The current blade angle control expected value is determined according to the calculation of N2r25. At the steady state of the engine, due to air flow disturbance, measurement interference and control, N2r25 swings, and then the blade angle control expected value a2Dem calculated based on N2r25 also swings, thereby causing the actual position control of a2 to swing to a large extent. The present technology filters N2r25, which can make the calculation result of a2Dem more stable, thereby reducing the steady-state swing of a2 and improving the control quality, which is beneficial to improving the aerodynamic stability of the engine. SUMMARY

[0007] In order to solve the above problems, the present application provides a control method for reducing the steady-state swing amount of the adjustable blade angle at the compressor inlet, comprising:

[0008] Step S1: calculating the converted rotating speed N2r25 of the high-pressure rotor 25 of the engine;

[0009] Step S2: filtering the converted speed N2r25 to obtain a filtered output value N2r25_1;

[0010] Step S3: calculating a desired value a2Dem for controlling the compressor inlet adjustable blade angle a2 based on the filtered output value N2r25_1;

[0011] Step S4: performing closed-loop control on the compressor inlet adjustable blade angle a2 by using the desired value a2Dem.

[0012] Preferably, the method of filtering the converted speed N2r25 in step S2 comprises:

[0013] Step S21: calculating a deviation value ΔN2r25 by subtracting a previous period value N2r25_Pre of the converted speed N2r25 from the converted speed N2r25;

[0014] Step S22: outputting a determination result ΔN2r25_1=0 when abs(ΔN2r25)≤A, and outputting a determination result ΔN2r25_1=ΔN2r25 when Abs(ΔN2r25)>A, A being an adjustable parameter;

[0015] Step S23: calculating the filtered output value N2r25_1 by summing the determination result ΔN2r25_1 and the previous period value N2r25_Pre of the converted speed N2r25.

[0016] Preferably, the converted speed N2r25 of the engine high-pressure rotor 25 section is calculated by using the engine high-pressure rotor speed N2 and the temperature T25 of the engine high-pressure rotor 25 section.

[0017] Preferably, the specific method of performing closed-loop control on the compressor inlet adjustable blade angle a2 by using the desired value a2Dem comprises:

[0018] calculating a deviation value Δa2 by subtracting a feedback value a2_s of the actuator cylinder of the compressor inlet adjustable blade angle a2 from the desired value a2Dem, and using a PID controller to control the release of the control current of the actuator based on the deviation value Δa2, thereby controlling the actuation of the actuator cylinder of the compressor inlet adjustable blade angle a2.

[0019] Preferably, step S22 is implemented by using a determination module and a selection module,

[0020] The determination module sets a threshold value A, and outputs a determination result of 1 when abs(ΔN2r25)≤A is satisfied, and outputs a determination result of 0 when Abs(ΔN2r25)>A is satisfied, indicating that the engine is in a non-stable state;

[0021] The selection module switches to the lower path when the result of the determination module is 1, and outputs the determination result ΔN2r25_1=0; the selection module switches to the upper path when the result of the determination module is 0, and outputs the determination result ΔN2r25_1=ΔN2r25.

[0022] Preferably, the initial value of the filtered output value N2r25_1 is set as N2r25, and the initial value of the previous period value N2r25_Pre of the filtered output value of the conversion speed is set as 0.

[0023] The advantages of the present application include: the present application adds a filtering algorithm on the basis of the current blade angle control instruction design method, so that the a2 control quality swing amount is smaller in the steady state. At the same time, the filtering algorithm can adapt to the different control quality requirements in the steady state and the transition state, reduce the a2 control swing amount in the steady state, improve the engine control quality and stability, and will not affect the a2 fast response performance in the transition state. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a control block diagram of a control method for reducing the steady-state swing amount of the adjustable blade angle at the inlet of the compressor according to a preferred embodiment of the present application;

[0025] Figure 2 is a principle diagram of N2r25 filtering according to a preferred embodiment of the present application.

[0026] Figure 3 is a processing effect diagram of N2r25 after the filtering algorithm;

[0027] Figure 4 is an influence diagram of a2Dem after the filtering algorithm in the transition state;

[0028] Figure 5 is an influence diagram of a2Dem after the filtering algorithm in the steady state;

[0029] Figure 6 is an influence diagram of the a2 swing amount after the filtering algorithm. DETAILED DESCRIPTION

[0030] In order to make the technical solutions and advantages of the present application clearer, the technical solutions of the present application will be further described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are only part of the embodiments of the present application, and are only used to explain the present application, but not to limit the present application. It should be noted that, for the purpose of description, only parts related to the present application are shown in the drawings, and other related parts can be referred to the usual design. In the case of no conflict, the embodiments in the present application and the technical features in the embodiments can be combined to obtain new embodiments.

[0031] AsFigures 1-2 as shown,

[0032] Principle

[0033] The filtering algorithm proposed in the application filters N2r25, and the filtering function is to reduce the fluctuation of N2r25 in the steady state to obtain the most stable N2r25_1. The filtered N2r25_1 is used to calculate a2Dem to obtain a more stable a2 control instruction (a2Dem). Thus, the purpose of reducing the steady-state swing is achieved, and the control quality is improved. It should be noted that the filtering algorithm should not affect the a2 control instruction of the engine in the transition process, so as to avoid the lag caused by filtering, which leads to slow a2 following in the transition process, and thus causes problems such as surge. Therefore, the problem solved by the present application is to propose an N2r25 filtering algorithm for a2 instruction calculation, which can adapt to different control objectives in steady state and transition state, and will not cause slow a2 response due to filtering in the transition state, that is, it has no effect on the transition state; in the steady state, the a2Dem is as stable as possible, thereby improving the steady-state control quality.

[0034] The specific control method comprises:

[0035] Step S1: calculating the converted speed N2r25 of the high-pressure rotor 25 section of the engine;

[0036] Step S2: filtering the converted speed N2r25 to obtain a filtered output value N2r25_1;

[0037] Step S3: calculating the expected value a2Dem of the adjustable blade angle a2 of the compressor inlet based on the filtered output value N2r25_1;

[0038] Step S4: subtracting the expected value a2Dem from the actuator feedback value a2_s of the adjustable blade angle a2 of the compressor inlet to obtain a deviation value Δa2, and a PID controller controls the release of the control current of the actuating mechanism based on the deviation value Δa2, thereby controlling the actuation of the actuator of the adjustable blade angle a2 of the compressor inlet.

[0039] The filtering method of the converted speed N2r25 in step S2 comprises:

[0040] Step S21: subtracting the converted speed N2r25 from the previous period value N2r25_Pre of the converted speed filtering output value to obtain a deviation value ΔN2r25;

[0041] Step S22: when abs(ΔN2r25)≤A, output the determination result ΔN2r25_1=0; when Abs(ΔN2r25)>A, output the determination result ΔN2r25_1=ΔN2r25, and A is an adjustable parameter;

[0042] Step S23: obtain the filtered output value N2r25_1 by combining the determination result ΔN2r25_1 with the previous cycle value N2r25_Pre of the converted rotational speed filtered output value.

[0043] Preferably, the converted rotational speed N2r25 of the engine high-pressure rotor 25 section is calculated by the engine high-pressure rotor rotational speed N2 and the temperature T25 of the engine high-pressure rotor 25 section.

[0044] Preferably, step S22 is implemented by a determination module and a selection module.

[0045] The determination module sets a small threshold A to determine the absolute value of ΔN2r25. When the engine is in a steady state, ΔN2r25 is small, satisfying abs(ΔN2r25)≤A, and the output determination result is 1; when Abs(ΔN2r25)>A, it is considered that the engine is in a non-steady state, and the determination result is 0.

[0046] The selection module uses the outputs 0 and 1 of the determination module to control the output ΔN2r25_1 of the selection module. When the result of the determination module is 1, the selection module switch is in the lower path, and the output ΔN2r25_1=0. When the result of the determination module is 0, the selection module switch is in the upper path, and the output ΔN2r25_1=ΔN2r25.

[0047] Preferably, the initial value of the filtered output value N2r25_1 is set to N2r25, and the initial value of the previous cycle value N2r25_Pre of the converted rotational speed filtered output value is set to 0.

[0048] The specific implementation steps of the filtering algorithm are as follows:

[0049] 1) Set the initial values, N2r25_1(1)=N2r25(1), N2r25_Pre(1)=0;

[0050] 2) According to the order of the signal flow, the N2r25 input N2r25(k) of the current cycle k(k=2,3,4,……) is calculated

[0051] ΔN2r25(k)=N2r25(k)-N2r25_Pre(k-1);

[0052] 3) According to the comparison of ΔN2r25(k) and the threshold A (A is an adjustable parameter), the outputs 0 and 1 of the determination module are calculated.

[0053] 4) The selection module determines the output ΔN2r25_1(k) of the current cycle according to the output of the determination module.

[0054] 5) Summing N2r25_Pre(k-1) and ΔN2r25_1(k) yields the current period filter output N2r25_1(k);

[0055] 6) Update N2r25_Pre to the current period: N2r25_Pre(k) = N2r25_1(k)

[0056] Step 1) is the initialization process, executed once. Steps 2) through 6) are executed once per cycle. Note: For digital electronic control systems, the control software is calculated and iteratively updated periodically, where k = 1, 2, 3, ... represents the k-th calculation cycle of the digital electronic controller.

[0057] 3. Simulation Verification

[0058] Simulation models of the current control method and the proposed filtering algorithm are established separately. The differences in control quality of the proposed algorithm in the transient and steady-state processes (a2) are compared and analyzed. Figure 4 The comparison curves for N2r25_1 after steady-state filtering are shown. Simulation results indicate that this algorithm has no impact on a2Dem during the transient process and does not affect the a2 response speed. In steady state, it effectively reduces blade angular oscillation caused by speed fluctuations.

[0059] This invention, based on the current blade angle control command design method, adds a filtering algorithm, which reduces the oscillation of the a2 control quality in steady state. Simultaneously, this filtering algorithm can adapt to the different control quality requirements in steady and transient states, reducing the a2 control oscillation in steady state, improving engine control quality and stability, and not affecting the a2 rapid response performance in transient state.

[0060] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A control method for reducing the amount of steady state swing of compressor inlet variable stator angle, characterized by, The control method comprises the following steps: Step S1: calculating a converted rotating speed N2r25 of the engine high-pressure rotor 25 section; Step S2: filtering the converted rotating speed N2r25 to obtain a filtered output value N2r25_1; Step S3: calculating a desired value a2Dem for controlling the compressor inlet adjustable blade angle a2 based on the filtered output value N2r25_1; Step S4: performing closed-loop control on the compressor inlet adjustable blade angle a2 by using the desired value a2Dem; The filtering method of the converted rotating speed N2r25 in step S2 comprises the following steps: Step S21: calculating a deviation value ΔN2r25 by subtracting a previous period value N2r25_Pre of the converted rotating speed filtered output value from the converted rotating speed N2r25; Step S22: when abs(ΔN2r25)≤A, outputting a determination result ΔN2r25_1=0; when abs(ΔN2r25)>A, outputting a determination result ΔN2r25_1=ΔN2r25, A being an adjustable parameter; Step S23: calculating the filtered output value N2r25_1 by summing the determination result ΔN2r25_1 and the previous period value N2r25_Pre of the converted rotating speed filtered output value.

2. The control method of reducing the amount of steady state swing of compressor inlet variable stator angle of claim 1, wherein, The converted rotating speed N2r25 of the engine high-pressure rotor 25 section is calculated by using the engine high-pressure rotor rotating speed N2 and the temperature T25 of the engine high-pressure rotor 25 section.

3. The control method of reducing the amount of steady state swing of compressor inlet variable stator angle of claim 1, wherein, The specific method of performing closed-loop control on the compressor inlet adjustable blade angle a2 by using the desired value a2Dem comprises the following steps: calculating a deviation value Δa2 by subtracting a feedback value a2_s of the actuator cylinder of the compressor inlet adjustable blade angle a2 from the desired value a2Dem, and then controlling the actuator cylinder of the compressor inlet adjustable blade angle a2 to act by using a release control current of an actuator based on the deviation value Δa2.

4. The control method of claim 1, wherein Step S22 is specifically implemented by using a determination module and a selection module, the determination module is configured to set a threshold A, and when abs(ΔN2r25)≤A, output a determination result of 1; when abs(ΔN2r25)>A, consider that the engine is in a non-stable state, and output a determination result of 0; the selection module is configured to, when the determination module outputs the determination result of 1, switch to a lower path and output a determination result ΔN2r25_1=0; and when the determination module outputs the determination result of 0, switch to an upper path and output a determination result ΔN2r25_1=ΔN2r25.

5. The control method of reducing the amount of steady state swing of compressor inlet variable stator angle of claim 1, wherein, The initial value of the filtered output value N2r25_1 is set as N2r25, and the initial value of the previous period value N2r25_Pre of the converted rotating speed filtered output value is set as 0.

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