Control apparatus and control method of variable stator blade

Abstract

To provide a control apparatus and a control method of variable stator blade capable of preventing the deterioration of service life of a gas-turbine engine by preventing the thrust of a driving device of the variable stator from rising.SOLUTION: A control apparatus of variable stator blade includes an arm 21 connected with a stationary vane 11 of an axial compressor 1, a rotary ring 22 which is connected with one end part of the arm 21 and is located on an outer periphery of a casing 10 of the axial compressor 1, a driving device 40 which rotates the stationary vane 11 via the arm 21 by rotating the rotary ring 22 and a controller CL which controls the driving device 40 by means of a command signal. The controller CL has a deceleration dead zone setting part 51 which performs deceleration dead zone control for invalidating the command signal during a predetermined time after displacing the stationary vane 11 to an objective installation angle θ, and an offset part 52 which returns the driving device 40 as many as a predetermined distance in such a direction as to relax an elastic energy stored in the arm 21, the rotary ring 22 and the driving device 40.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a control device and a control method for a variable stator vane mechanism that adjusts the mounting angle of stator vanes of an axial flow compressor used in a gas turbine engine, a turbo chiller, or the like. [Background technology]

[0002] Axial compressors are used in gas turbine engines to compress gas. The axial compressor compresses the intake air to high pressure and sends it to the combustor. The high-temperature, high-pressure gas burned in the combustor is recovered as rotational energy in the turbine and then discharged. Gas turbine compressors can enter an unstable state known as rotating stall during engine startup. Operating a gas turbine engine for extended periods in this unstable state can result in engine start-up delays and incomplete startup.

[0003] To avoid this, air bleeding is performed at intermediate stages of the compressor, and variable stator vane mechanisms are used at front stages.For example, Patent Document 1 describes a variable stator vane mechanism for an axial flow compressor that is highly durable and that prevents over-rotation of the rotating ring that supports the stator vanes by providing friction pads on the casing of the axial flow compressor, making it possible to properly adjust the mounting angle of the stator vanes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-117657 Summary of the Invention [Problem to be solved by the invention]

[0005] However, mechanical reaction forces such as frictional resistance and elastic energy in the drive unit increase over time, causing the thrust of the variable stator vane drive unit to rise, resulting in an increase in the motor temperature of the drive unit.The increase in motor temperature can cause problems with the drive unit and shorten the lifespan of the gas turbine engine.

[0006] The disclosure of the present application has been made to solve the above-mentioned problem, and provides a variable stator vane control device and control method that can prevent a reduction in the lifespan of a gas turbine engine by suppressing an increase in thrust of a variable stator vane drive device. [Means for solving the problem]

[0007] A variable stator vane control device according to the present disclosure is a control device that controls the mounting angle of a stator vane of an axial flow compressor, and includes an arm connected to the stator vane, a rotating ring connected to one end of the arm and positioned on the outer periphery of a casing of the axial flow compressor, a drive device that rotates the rotating ring to rotate the stator vane via the arm, and a controller that controls the drive device with a command signal, and the controller has a dead band setting unit that performs dead band control that invalidates the command signal for a predetermined time after moving the stator vane to a target mounting angle, and an offset unit that returns the drive device a predetermined distance in a direction that relieves elastic energy stored in the arm, the rotating ring, and the drive device after the predetermined time has elapsed. [Effects of the Invention]

[0008] According to the variable stator vane control device according to the present disclosure, it is possible to prevent a decrease in the lifespan of the gas turbine engine by suppressing an increase in the thrust of the variable stator vane drive device. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram showing a power generation system of a gas turbine engine employing a variable stator vane mechanism of the present disclosure. [Figure 2] FIG. 2 is a longitudinal cross-sectional view showing a variable stator vane mechanism of the present disclosure. [Figure 3] FIG. 2 is a partial enlarged longitudinal cross-sectional view of a variable stator vane mechanism of the present disclosure. [Figure 4] FIG. 4 is a diagram showing a portion of the blade row of FIG. 3. [Figure 5] FIG. 2 is a longitudinal cross-sectional view showing a row of stator vanes of an axial compressor of the present disclosure. [Figure 6] FIG. 2 is a view of the variable stator vane mechanism of the present disclosure as viewed from the axial direction of the compressor. [Figure 7] 4A and 4B are diagrams illustrating the state of the drive device of the present disclosure and the transition of the motor temperature. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a power generation system of a gas turbine engine GT that employs a variable stator vane mechanism according to the present disclosure. In the figure, the gas turbine GT comprises, as its main components, an axial compressor (hereinafter simply referred to as "compressor") 1, a combustor 2, and a turbine 3. Compressed air A supplied from the compressor 1 and fuel F supplied from a fuel supply device (not shown) are combusted in the combustor 2, and high-temperature, high-pressure combustion gas G generated by the combustion is supplied to the turbine 3 to drive it. Exhaust gas E is discharged from the turbine 3. The compressor 1 is driven by the turbine 3 via a rotary shaft 4, and the turbine 3 also drives an external load 6, such as a generator, via a reduction gear 5.

[0011] In the following description, unless otherwise specified, the terms "axial direction," "radial direction," and "circumferential direction" refer to the axial direction, radial direction, and circumferential direction of the compressor 1, respectively.

[0012] As shown in Fig. 2, in this embodiment, an axial flow type compressor is used as the compressor 1. The compressor 1 has a double cylindrical structure extending in the axial direction X of the compressor 1, and is made up of a compressor rotor 8 that constitutes part of the rotating shaft 4 (Fig. 1) of the gas turbine GT, and an outer compressor stator 9. A compression passage 14 that compresses air A drawn in from an intake passage 13 is formed between the rotor 8 and the stator 9.

[0013] The stator 9 is generally composed of a compressor casing 10 and a plurality of stator vane rows arranged in the axial direction X on the inner circumferential surface of the casing 10. Each stator vane row is formed of a plurality of compressor stator vanes 11 arranged at equal intervals in the circumferential direction. Some of the stator vanes 11 are variable stator vanes whose installation angle is variable, and the compressor 1 is equipped with a variable stator vane mechanism 7 that controls the installation angle of these variable stator vanes.

[0014] The rotor 8 is generally composed of a plurality of rotor disks 15 arranged in the axial direction X, and a plurality of compressor rotor blades 12 arranged at equal intervals in the circumferential direction on the outer periphery of each rotor disk 15. A row of rotor blades 12 arranged in the circumferential direction forms a row of rotor blades, and the plurality of rotor blade rows are arranged in the axial direction X. The stator blade rows and rotor blade rows are arranged alternately in the axial direction X.

[0015] 3, the control device for controlling the mounting angle of the stator vane 11 relative to the circumferential line H (FIG. 4) according to this embodiment includes an arm 21 connected to the stator vane 11, a rotating ring 22 connected to one end of the arm 21, a driving device 40 that rotates the rotating ring 22 to rotate the stator vane 11 via the arm 21, and a controller CL that controls the driving device 40 by a command signal. The controller CL has a dead band setting unit 51 and an offset unit 52, which will be described later.

[0016] A blade shaft 20 is integrally connected to the stator vane 11, which is a variable stator vane. The blade shaft 20 penetrates the casing 10 in the radial direction, and its tip protrudes from the outer wall of the casing 10. The blade shaft 20 rotates about its axis, thereby changing the mounting angle of the stator vane 11.

[0017] As shown in FIG. 4 , the variable stator vane mechanism 7 adjusts the amount of air that flows into the compressor 1 by adjusting the mounting angle θ of the stator vanes 11 in a circumferential cross section of the compressor 1 so as to change the outflow angle α of the stator vane with respect to the axial direction X. Here, the mounting angle θ is the angle formed by the circumferential line H of the stator vane 11 and the chord L (the line connecting the leading edge and the trailing edge). When the mounting angle θ is adjusted to be larger, that is, when the outflow angle α is adjusted to be smaller, the axial velocity of the air increases, and the amount of air that flows into the compressor 1 increases. In this embodiment, as shown in FIG. 3 , the variable stator vane mechanism 7 is provided to adjust the mounting angle θ of the stator vanes 11 in four rows from the first row (the row on the most upstream side) to the fourth row of the compressor 1. The stator vanes 11 in the first row from the inlet of air A are sometimes called guide vanes.

[0018] 5, a spring seat 26, a spring body 25, and the base end of the arm 21 are fitted in this order onto the end of the blade shaft 20 protruding from the casing 10, and are prevented from coming off by a nut 27. The spring body 25, which is interposed between the base end of the arm 21 and the casing 10, biases the blade shaft 20 so that the axial direction of the arm 21 is approximately perpendicular to the extension direction of the arm 21. In addition, the portion of the blade shaft 20 into which the arm 21 is fitted has a rotation-preventing shape, and the arm 21 rotates integrally with the blade shaft 20 and the stator blade 11 around the axis of the blade shaft 20.

[0019] An annular rotating ring 22 is provided on the outer periphery of the casing 10 in correspondence with each row of variable stator vanes. In this embodiment, four rotating rings 22 are provided on the outer periphery of the casing 10, aligned in the axial direction X of the compressor 1. The rotating rings 22 are fitted onto the outer wall of the casing 10 with a gap between them.

[0020] Each of the tip ends of the multiple arms 21, which correspond to one row of variable stator vanes, is connected to one rotating ring 22. More specifically, the rotating ring 22 has a C-shaped cross section, and the tip ends of the arms 21 are fitted into the openings of this C, and a shaft member 28 passes through the rotating ring 22 and the tip ends of the arms 22.

[0021] The portion of the casing 10 through which the blade shafts 20 of each row are inserted and its peripheral edge form a circumferential protrusion 101 (annular rib) that continues in the circumferential direction. The outer peripheral surface of this circumferential protrusion 101 forms a circumferential protruding surface 102 that is located radially outward from the normal outer wall surface of the casing 10. The arms 21 fitted to the blade shafts 20 that protrude radially outward from the circumferential protrusion 101 are located outer than the circumferential protruding surface 102 (i.e., radially outside the compressor 1), and the rotating ring 22 connected to these arms 21 is located outer than the circumferential protruding surface 102. The position of the rotating ring 22 in the axial direction X of the compressor 1 is offset in the axial direction X from the circumferential protrusion 101. In this way, there is a radial distance between the inner periphery of the rotating ring 22 and the normal outer wall surface of the casing 10.

[0022] The compressor 1 also has elastic bodies 23 attached at multiple locations on the inner circumferential surface of the rotating ring 22, and these elastic bodies 23 abut against the outer wall of the casing 10. Each elastic body 23 is a thin metal plate, a so-called leaf spring, and is elastically deformable.

[0023] One end 23a of the elastic body 23 in the axial direction X of the compressor 1 is attached to the rotating ring 22 with a fastener 24 consisting of a bolt and a nut. The other end 23b of the elastic body 23 in the axial direction X is provided with a sliding surface 23c, and this sliding surface 23c is in contact with the circumferential protruding surface 102 of the casing 10. As a result, when the rotating ring 22 rotates around the casing 10, the end 23b of the elastic body 23 slides on the circumferential protruding surface 102 of the casing 10, and rotates integrally with the rotating ring 22.

[0024] As shown in Figure 6, the rotating rings 22 are rotationally driven by a driving device 40. When a certain row of rotating rings 22 rotates around the outer periphery of the casing 10, the multiple arms 21 connected to this rotating ring 22 are operated in synchronization, causing the stator vanes 11 in that row to rotate in synchronization around the corresponding blade shafts 20 (Figure 4), changing the installation angle θ (Figure 4) of the stator vanes 11. The driving device 40 of the variable stator vane mechanism 7 according to this embodiment is configured to drive all of the rotating rings 22 in a linked manner in order to simultaneously change the installation angle θ of the four rows of variable stator vanes provided in the compressor 1.

[0025] The specific configuration of the driving device 40 will be described below. As shown in FIG. 3 , an interlocking shaft 29 extending parallel to the axial direction X of the compressor 1 is supported on the outer wall of the casing 10. Four operating levers 30 are provided on the interlocking shaft 29 and rotate integrally with the interlocking shaft 29. Each operating lever 30 is connected to the rotating ring 22 shown in FIG. 6 via a rod 31. A drive lever 32 that rotates integrally with the interlocking shaft 29 is also provided on the interlocking shaft 29, and an actuator AC that rotates the drive lever 32 is connected to the drive lever 32. The actuator AC according to this embodiment is an electric actuator including an electric motor (motor) 33 as a drive source, a cylinder 35, and a cylinder rod (ball screw) 34 that is driven by the electric motor 33 to move back and forth from the cylinder 35. However, the present invention is not limited to this, and may be, for example, a hydraulic actuator. The tip of the cylinder rod 34 is connected to the drive lever 32, and the cylinder 35 is supported on the outer wall of the casing 10.

[0026] In the above configuration, when the electric motor 33 operates and the cylinder rod 34 moves forward or backward, the drive lever 32 and each operating lever 30 rotate around the interlocking shaft 29, causing the four rotating rings 22 in Figure 3 to rotate in unison. This causes the stator vanes 11 in each row connected to each rotating ring 22 to move in unison, and their mounting angles θ (Figure 4) change in unison.

[0027] Note that the length of each rod 31 in Figure 6 is adjustable, and the angle of the operating lever 30 can be adjusted by changing the length of the rod 31. Furthermore, the installation angles θ of all of the stator vanes 11 in one row connected to one rotating ring 22 are changed by the same angle. The change angle of the installation angle θ of each stator vane 11, which is a variable stator vane, may differ for each row. For example, the lever ratio of the drive lever 32 may be adjusted appropriately so that the change angle of the stator vanes 11 in the rear row is smaller.

[0028] Next, the specific operation of the driving device 40 will be described below. A command signal from the controller CL in Fig. 3 operates the electric motor 33 in Fig. 6 to move the cylinder rod 34 forward (or backward), and the stator vanes 11 connected to each rotating ring 22 move in conjunction with each other, changing the mounting angle θ of the stator vanes 11 to a target angle. Thereafter, the dead-band setting unit 51 in Fig. 3 performs dead-band control for a predetermined time to invalidate the command signal from the controller CL. Here, the "predetermined time" refers to the time until control by the offset unit 52, which will be described later, is performed, and is set arbitrarily by the dead-band setting unit 51.

[0029] At this time, elastic energy that attempts to return to the state before the change in the mounting angle θ is stored in the arm 21, rotating ring 22, and drive unit 40 in FIG. 6. Therefore, after the predetermined time has elapsed, the offset unit 52 (FIG. 3) moves the cylinder rod 34 back a predetermined distance in a direction that relieves the elastic energy stored in the arm 21, rotating ring 22, and drive unit 40. That is, when the cylinder rod 34 is moved forward to move the mounting angle θ of the stator vanes 11 to the target angle, the cylinder rod 34 is moved backward a predetermined distance. When the cylinder rod 34 is moved backward to move the mounting angle θ of the stator vanes 11 to the target angle, the cylinder rod 34 is moved forward a predetermined distance. Here, the "predetermined distance" refers to a distance that allows the distortion of the rotating ring 22 to be restored and causes almost no change in the mounting angle θ of the stator vanes 11.

[0030] 7 shows the state of the drive unit 40 and the transition of the motor temperature 33 when the control of the present disclosure is performed. After the dead zone setting described above is performed, if the offset unit 52 (FIG. 3) returns the cylinder rod 34 a predetermined distance in a direction that relieves the elastic energy stored in the arm 21, the rotating ring 22, and the drive unit 40 shown in FIG. 6, for example, by slightly reducing the variable stator vane (VSV) command value, the thrust of the drive unit 40 is reduced, and as a result, the temperature of the motor 33 gradually drops.

[0031] According to the variable stator vane control device of the present disclosure, dead band control can be performed to suppress noise from the control device and minute movements of the drive device 40 caused by minute movements of the gas turbine engine GT, thereby reducing the sliding distance between mechanical parts and suppressing wear. Furthermore, after a predetermined time has elapsed since the start of dead band control, the cylinder rod 34 of the drive unit 40 is returned a predetermined distance in a direction that relieves the elastic energy stored in the arm 21, the rotating ring 22, and the drive unit 40, thereby easing the reaction force caused by the elastic energy that acts on the motor 33 of the drive unit 40 and reducing the thrust of the drive unit 40. This makes it possible to prevent an increase in the temperature of the motor 33 of the drive unit 40 and, ultimately, a shortened lifespan of the gas turbine engine GT.

[0032] The drive device 40 may be an electric actuator having an electric motor 33 and a ball screw 34 driven by the electric motor 33. In the configuration of the present disclosure, the mounting angle θ of the stator vane 11 can be changed accurately and quickly.

[0033] The present disclosure also includes the following variable stator vane control method. an arm 21 connected to the stator blade 11 of the axial flow compressor 1; a rotating ring 22 connected to one end of the arm 21 and positioned on the outer periphery of the casing 10 of the axial flow compressor 1; a drive device that rotates the stator vane via the arm by rotating the rotating ring, the control method comprising: After the stator blade 11 is moved to the target mounting angle θ, dead band control is performed for a predetermined time to invalidate a command signal to the drive device 40, A control method in which, after the predetermined time has elapsed, the driving device 40 is returned by a predetermined distance in a direction that relieves the elastic energy stored in the arm 21, the rotating ring 22, and the driving device 40.

[0034] According to the control method for variable stator vanes of the present disclosure, dead band control can be performed to suppress noise from the control device and minute movements of the drive device 40 caused by minute movements of the gas turbine engine GT, thereby reducing the sliding distance between mechanical parts and suppressing wear. Furthermore, after a predetermined time has elapsed since the start of dead band control, the cylinder rod 34 of the drive unit 40 is returned a predetermined distance in a direction that relieves the elastic energy stored in the arm 21, the rotating ring 22, and the drive unit 40, thereby easing the reaction force caused by the elastic energy that acts on the motor 33 of the drive unit 40 and reducing the thrust of the drive unit 40. This makes it possible to prevent an increase in the temperature of the motor 33 and, ultimately, a shortened lifespan of the gas turbine engine GT.

[0035] Although the embodiments of the present disclosure have been described above, the disclosed embodiments are illustrative in all respects and are not limiting. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0036] REFERENCE SIGNS LIST 1... compressor, 10... (compressor) casing, 11... stationary blade, 21... arm, 22... rotating ring, 33... electric motor (motor), 34... cylinder rod (ball screw), 40... drive device, 51... dead band setting unit, 52... offset unit, CL... controller

Claims

1. A control device for controlling an installation angle of a stator vane of an axial flow compressor, an arm connected to the stator vane; a rotating ring connected to one end of the arm and positioned on the outer periphery of a casing of the axial flow compressor; a drive device that rotates the rotary ring to rotate the stator blades via the arms; a controller that controls the drive device by a command signal; the controller has a dead band setting unit that performs dead band control for invalidating the command signal for a predetermined time after moving the stator blade to a target mounting angle; a control device having an offset unit that returns the drive device a predetermined distance in a direction that relieves the elastic energy stored in the arm, the rotating ring, and the drive device after the predetermined time has elapsed.

2. 2. The control device according to claim 1, The drive device is a control device that is an electric actuator having an electric motor and a ball screw driven by the electric motor.

3. an arm connected to a stator vane of the axial flow compressor; a rotating ring connected to one end of the arm and positioned on the outer periphery of a casing of the axial flow compressor; a drive device that rotates the stator vane via the arm by rotating the rotating ring, After the stationary blade is moved to a target mounting angle, dead band control is performed for a predetermined time to invalidate a command signal to the drive device; a control method for returning the drive device by a predetermined distance in a direction that relieves the elastic energy stored in the arm, the rotating ring, and the drive device after the predetermined time has elapsed.

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