Semi-active gyro mass damper system for vibration control of offshore floating type fan tower

Abstract

The invention provides a semi-active gyro mass damper system for vibration control of an offshore floating type fan tower. Comprising a spring, a semi-active gyroscope mass damper, a tuned mass block, a supporting frame, a split type cylinder body, a ball screw suite, a thrust ball bearing, a mass flywheel, a coupler, a piston, a coil, an air bag compensator, magnetorheological fluid, a sealing rubber ring, a guider and a Model Predictive Control (MPC) controller. The semi-active gyro mass damper system is installed at the top end of a tower of a fan, and energy of a controlled system is well consumed through the mass amplification effect generated by a ball screw suite and a mass flywheel. And meanwhile, semi-active control is realized through the MPC controller and the magneto-rheological device. Compared with the existing vibration suppression technology, the vibration suppression device has the advantages of small tuning mass, small installation space, real-time damping adjustment, good vibration suppression effect and the like.

Description

Technical Field

[0001] The present invention relates to the field of structural vibration control, and particularly to a semi-active gyro mass damper system for vibration control of an offshore floating wind turbine tower. Background Art

[0002] Compared with onshore wind energy, offshore wind energy has the advantages of low turbulence intensity, high wind speed, and no occupation of land area. With the development of offshore wind power resources, the future trend of wind power generation is to develop towards deep and far seas. For deep sea areas (water depth exceeding 60m), from the perspectives of safety and economy, floating platforms need to be used. Different from fixed wind turbines, the operating environment of floating wind turbines is more complex, and the relevant rotations and translations of the floating platform caused by wave and wind loads will significantly increase the oscillations and loads of the wind turbine. The wind turbine tower is dynamically sensitive, so tower vibration may damage the acceleration-sensitive equipment in the nacelle, resulting in problems such as wind turbine failure shutdown, reduced output power, and reduced service life. Therefore, how to suppress the vibration of the offshore floating wind turbine tower and the dynamic response of key components to ensure the stable operation of the floating wind turbine is the focus of attention of many scholars at present.

[0003] At present, many researchers have applied structural control methods to the vibration control of wind turbines. Among them, passive structural control is the most widely used due to its simple structure and high reliability. As a typical representative of passive structural control, the tuned mass damper consists of a mass block, a spring, and viscous damping. The tuned mass damper applies a force opposite to the movement direction of the controlled structure by the movement of the mass block, thereby consuming the energy of the controlled structure to achieve the vibration reduction effect. It should be noted that if the tuned mass damper needs to obtain better control effects, it requires a larger mass of the mass block and a larger working stroke. Although the tuned mass damper has proved its certain effect in suppressing the vibration of the wind turbine tower, its effect is still limited. In order to further obtain better suppression effects, semi-active control is introduced into the field of vibration suppression of offshore wind turbine towers. Semi-active control can adjust the damping of the damping system in real time according to the change of load through some optimization algorithms and variable damping mechanisms, and obtains better vibration suppression effects. Although the semi-active control has improved the effect compared with the passive control, the performance improvement obtained by changing the damping is still limited. To obtain better control effects, it is still necessary to increase the mass of the mass block and the working stroke of the damper. For offshore floating wind turbines, the mass of the mass block has a greater impact on the floating platform, and an excessive mass block will affect the stability of the platform. At the same time, the structure of offshore wind turbines is relatively complex. Whether it is the nacelle or the top of the tower, the installation space left for the damper system is very limited, and the working stroke of the damper is very limited in this case.

[0004] In summary, although there are already many methods to suppress the vibration of the offshore wind turbine tower, there are still problems such as poor control effect, large mass block and large working stroke. Summary of the Invention

[0005] The object of the present invention is to propose a semi-active gyro mass damper system for vibration control of an offshore floating wind turbine tower; the semi-active gyro mass damper system is installed at the top of the tower of the wind turbine, and a mass amplification effect is generated through a ball screw kit and a mass flywheel to well consume the energy of the controlled system. At the same time, semi-active control is also achieved through an MPC controller and a magnetorheological device. Compared with the existing vibration suppression technologies, it has the advantages of small tuning mass, small installation space, real-time damping adjustment and good vibration suppression effect.

[0006] To achieve the above object, the technical solution of the present invention is: a semi-active gyro mass damper system for vibration control of an offshore floating wind turbine tower, including a semi-active gyro mass damper assembly and an MPC (Model Predictive Control) controller for controlling the damping; a ball screw structure is adopted in the semi-active gyro mass damper to convert the translational motion of the mass block into the rotational motion of the mass flywheel, and this conversion of the motion form will generate a large axial force opposite to the motion direction of the mass block, so as to achieve the effect of mass amplification of the mass block, so that the damper system only needs a very small apparent tuning mass to obtain the suppression effect of a large mass. The magnetorheological damping device can change the rheological characteristics of the magnetorheological fluid in the cylinder by changing the current passing through its coil, so that the damping force received during the piston movement is changed;

[0007] The semi-active gyro mass damper assembly structurally includes a tuned mass block, a spring, a semi-active gyro mass damper and a support frame; the support frame is a cantilever beam fixedly connected to the wall of the wind turbine tower at one end, and sliding guides are arranged in parallel along the front and back directions of the wind turbine on the support frame; the tuned mass block slides on the sliding guides of the support frame through the pulleys provided at its bottom; the spring and the semi-active gyro mass damper are arranged in parallel; one end of the spring is fixedly connected to the wall of the wind turbine tower, and the other end is fixedly connected to the tuned mass block; the semi-active gyro mass damper includes an inertial mass part and a magnetorheological device part; one end of the semi-active gyro mass damper is fixedly connected to the mass block, and the other end is fixedly connected to a position on the wall of the wind turbine tower lower than the height where the semi-active gyro mass damper is located;

[0008] The MPC controller mainly includes a system prediction module, an objective function construction module and an optimization solution module, and the MPC controller is used to adjust the damping of the semi-active gyro mass damper in real time according to the load change during the operation of the offshore floating wind turbine.

[0009] Preferably, two sliding guide rails are arranged in parallel along the front and rear directions of the fan on the support frame, and the tuned mass damper slides on the two sliding guide rails of the support frame through two sets of pulleys provided at its bottom.

[0010] Preferably, the semi-active gyro mass damper includes a split cylinder block, the split cylinder block is composed of two semi-cylindrical cylinder blocks, and the two semi-cylindrical cylinder blocks are connected by bolts and nuts to form a cylindrical cylinder block; the inside of the cylindrical cylinder block is divided into an inertial mass cavity, a coupling cavity and a magnetorheological device cavity.

[0011] Preferably, grooves are provided on the cylinder wall of the mating surface of the two semi-cylindrical cylinder blocks for installing sealing rubber rings, and the sealing rubber rings are used to seal the internal cavity when the two semi-cylindrical cylinder blocks are connected to form a cylindrical cylinder block.

[0012] Preferably, the inertial mass part includes a ball screw, a ball nut, a mass flywheel, balls, two thrust ball bearings and a flat key;

[0013] The ball screw uses the round holes at both ends of the inertial mass cavity as a guiding device to translate in the axial direction of the cavity; the ball nut meshes with the thread on the screw through the balls in the middle threaded part of the ball screw; the translation of the ball screw is converted into the rotation of the ball nut through the threaded part;

[0014] The mass flywheel is connected to the ball nut through a flat key to rotate following the ball nut;

[0015] The two thrust ball bearings are respectively located at both ends of the inertial mass cavity. The outer ring of the thrust ball bearing is connected with the inner wall of the inertial mass cavity by interference fit, and the inner ring of the thrust ball bearing contacts both ends of the mass flywheel to fix the mass flywheel and prevent the mass flywheel from moving axially due to the axial force of the thread.

[0016] Preferably, the magnetorheological device part includes an inner piston, an outer piston, a guide, a coil, an airbag compensator, a Y-shaped sealing ring and magnetorheological fluid;

[0017] A through hole for the inner piston rod to pass through is provided at the end of the magnetorheological device cavity facing the inertial mass part, and a groove is provided on the side wall of the cavity at the through hole for installing a Y-shaped sealing ring to ensure the sealing of the magnetorheological device cavity;

[0018] The guide is installed in the magnetorheological device cavity. The outer ring of the guide fits with the inner wall of the magnetorheological device cavity, and the inner ring at one end of the guide is connected with the inner piston rod by interference fit to ensure that the guide reciprocates with the inner piston;

[0019] Both ends of the outer piston are closely attached to the inner walls of the guides, and bolts are used to connect the outer piston to the guides on both sides to facilitate the reciprocating movement of the outer piston and the guides together; the inner piston is located inside the outer piston;

[0020] The coil is installed in the groove provided on the cylindrical surface of the inner piston. After the coil is energized, a magnetic force circuit will be formed between the inner and outer pistons and the gap between them;

[0021] The magnetorheological fluid fills the entire cavity except for the inner and outer pistons, guides, coil, and airbag compensator. When the magnetorheological fluid passes through the magnetic force circuit, its rheological properties can be changed by the current passing through the coil within a few milliseconds;

[0022] The bottom of the airbag compensator is fixedly connected to the inner wall of the end of the magnetorheological device cavity away from the inertial mass part.

[0023] Preferably, the airbag compensator is filled with nitrogen; when the inner and outer pistons reciprocate in the magnetorheological device cavity, the change in the space inside the cavity caused by the inner piston rod entering and leaving the cavity makes the magnetorheological fluid unable to always fill the cylinder. In this case, the airbag compensator eliminates the space change brought by the piston movement by changing its own volume, so that the magnetorheological fluid always fills the cavity.

[0024] Preferably, the centers of both the ball screw and the inner piston rod are hollow, and both ends of the coil are led out of the cylindrical cylinder through the hollow parts of the inner piston rod and the ball screw.

[0025] Preferably, the end of the inner piston rod extending out of the magnetorheological device cavity is fixedly connected to one end of the ball screw extending out of the inertial mass cavity through a coupling to ensure that the inner piston rod and the ball screw reciprocate in the cylindrical cylinder at the same time; the coupling is located inside the coupling cavity.

[0026] Preferably, the MPC controller uses the MPC control algorithm to control the damping of the magnetorheological device, so that the damping of the magnetorheological device changes in real time according to the current load, breaking the limitation that the traditional tuned mass damper cannot change with the load due to the fixed damping coefficient; the specific design method of the MPC controller is as follows;

[0027] Step 1, construct an MPC system prediction model through the kinematic differential equation of the offshore floating wind turbine system. The equation of the MPC system prediction model is:

[0028]

[0029] In the formula and are the state change amount of the system and its first-order derivative respectively, y is the output change amount of the system, and the state change amount of the system is composed of and Define M, K, and c i They are respectively the mass matrix, stiffness matrix, and initial damping matrix of the controlled system, F is the external load of the controlled system; Δu represents the change in the system control input; the change in the system output is defined by C and D. Since the output of the system is the change in the system state, C is the identity matrix and D is the zero matrix; after discretization, the predicted discrete model of the system at the k-th moment is:

[0030]

[0031] Substitute the state change in Equation (b - 2) and the system output change y i (k), perform N-step iterative calculations, and convert the iterative formula into an equation expression in matrix form:

[0032]

[0033] In the formula, X k = [x(k|k) x(k + 1|k) … x(k + i|k) x(k + N|k)] T is the matrix set of all state changes x k+i within the prediction time domain at the k-th moment, Y k = [y(k|k) y(k + 1|k) … y(k + i|k) y(k + N|k)] T is the matrix set of all system output changes y k+i within the prediction time domain at the k-th moment, U k = [u s (k|k) u s (k + 1|k) … u s (k + i|k) u s (k + N - 1|k)] T is the matrix set of all system input changes y k+i within the prediction time domain at the k-th moment, L = [I A A 2 … A N T is the set of system state matrices at each moment within the prediction time domain, W is the set of control input matrices at each moment within the prediction time domain, is the set of system output matrices at each moment within the prediction time domain, O = [0 I A 2 … A N T ;

[0034] Step 2, construct an objective function based on the MPC system prediction model. The objective function J(U k ) of model predictive control is

[0035] ​​

[0036] where E K is the vector set of errors:

[0037]

[0038] where [0] is the zero matrix, and the designed controller needs to suppress the state change of the wind turbine system and make it tend to zero as much as possible. Therefore, all the values in the reference vector set R k are set to zero; U K is the vector set of control input changes, is a positive semi - definite symmetric time - varying matrix, is a positive definite symmetric time - varying matrix; Substitute E K into Equation b - 4 and combine it with the equation to construct the objective function J(U k ) as

[0039]

[0040] where and

[0041] Step 3: Minimize the objective function through the quadratic programming optimization algorithm to obtain the system control input change at the next moment. The control input is the change in the external input force; the control input here is the change in the external input force, and the external control force here is designed as the active control force. Since the present invention adopts semi - active control and cannot directly apply an external control force to the controlled system, this application uses a magneto - rheological damper to adjust the damping to change the damping force received by the controlled system, so as to obtain the same effect as directly applying an external control force to the controlled system; Based on this method, the change in the damping force ΔF c is equivalent to the change in the external control force ΔF; It should be noted that if the change in the external control force designed by active control exceeds the adjustment range of the magneto - rheological damper, then this control force cannot be equivalent by adjusting the damping coefficient. Therefore, the change in the damping force ΔF C is restricted:

[0042]

[0043] Since there is a direct relationship between the damping force received by the controlled system and the damping coefficient, convert the change in the damping force and the change in the damping:

[0044]

[0045] Step 4: Add the damping change obtained in Step 3 to the damping of the system at the previous moment to obtain the system damping at the current moment; use the damping coefficient at the current moment as the damping coefficient of the wind turbine dynamic model to solve for the state change of the wind turbine system at the current moment; finally, use the state change at the current moment as the input of the system prediction model at the next moment, and iterate cyclically to obtain the damping changes at all moments.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] (1) A semi-active gyro mass damper system is designed. This damper system has the ability of mass amplification, and only a very small tuned mass is needed to obtain a good vibration control effect. It not only reduces the tuned mass but also improves the vibration suppression effect.

[0048] (2) This damper system can obtain better control effects with only a very small working stroke, which greatly reduces the requirement of this damping system for installation space.

[0049] (3) This damping system has an MPC controller and a magnetorheological damping device, which can adjust the damping in real time according to the change of load to achieve semi-active control, and has a better vibration suppression effect than traditional control methods. Description of the Drawings

[0050] Figure 1 is an exploded view of the gyro mass damper in the semi-active gyro mass damper system of the present invention;

[0051] Figure 2 is a schematic diagram of the semi-active gyro mass damper system of the present invention installed on the top of an offshore floating wind turbine tower;

[0052] Figure 3 is a sectional view and a partial enlarged view of the gyro mass damper in the semi-active gyro mass damper system of the present invention;

[0053] Figure 4 is the control structure diagram of the MPC controller of the present invention.

[0054] In the figure, 1 - spring; 2 - semi-active gyro mass damper; 3 - tuned mass block; 4 - support frame; 5 - split cylinder block; 6 - hexagon nut; 7 - coil lead; 8 - ball screw; 9 - thrust ball bearing; 10 - mass flywheel; 11 - hexagon bolt; 12 - coupling; 13 - inner piston rod; 14 - outer piston; 15 - airbag compensator; 16 - magnetorheological fluid; 17 - sealing rubber ring; 18 - guide; 19 - Y-shaped sealing ring; 20 - ball nut; 21 - ball; 22 - flat key; 23 - coil. Detailed Embodiments

[0055] The following combines the attachedFigures 1-4 , a detailed description of the technical solution of the present invention will be given.

[0056] The present invention provides a semi - active gyro mass damper system for vibration control of an offshore floating wind turbine tower, which includes a semi - active gyro mass damper assembly and an MPC controller for controlling damping.

[0057] The semi - active gyro mass damper assembly structurally includes a tuned mass block 3, a spring 1, a semi - active gyro mass damper 2, and a support frame 4; the support frame 4 is a cantilever beam fixedly connected to the wall of the wind turbine tower at one end, and sliding guide rails are arranged parallel to the front - rear direction of the wind turbine on the support frame 4; the tuned mass block 3 slides on the sliding guide rails of the support frame 4 through pulleys provided at its bottom; the spring 1 and the semi - active gyro mass damper 2 are arranged in parallel; one end of the spring 1 is fixedly connected to the wall of the wind turbine tower, and the other end is fixedly connected to the tuned mass block 3; the semi - active gyro mass damper 2 includes an inertial mass part and a magnetorheological device part; one end of the semi - active gyro mass damper 2 is fixedly connected to the mass block 3, and the other end is fixedly connected to a position on the wall of the wind turbine tower lower than the height where the semi - active gyro mass damper 2 is located.

[0058] The MPC controller mainly includes a system prediction module, an objective function construction module, and an optimization solution module, and the MPC controller is used to adjust the damping of the semi - active gyro mass damper 2 in real time according to load changes during the operation of the offshore floating wind turbine.

[0059] In this embodiment, two sliding guide rails are arranged parallel to the front - rear direction of the wind turbine on the support frame 4, and the tuned mass block 3 slides on the two sliding guide rails of the support frame 4 through two groups of pulleys provided at its bottom.

[0060] In this embodiment, the semi - active gyro mass damper 2 includes a split cylinder 5, the split cylinder 5 is two semi - cylindrical cylinders, and the two semi - cylindrical cylinders are connected by hex bolts 11 and hex nuts 6 to form a cylindrical cylinder; the inside of the cylindrical cylinder is divided into an inertial mass cavity, a coupling cavity, and a magnetorheological device cavity.

[0061] In this embodiment, grooves are provided on the cylinder wall of the mating surface of the two semi - cylindrical cylinders for installing a sealing rubber ring 17, and the sealing rubber ring 17 is used to seal the internal cavity when the two semi - cylindrical cylinders are connected to form a cylindrical cylinder.

[0062] In this embodiment, the inertial mass part includes a ball screw 8, a ball nut 20, a mass flywheel 10, balls 21, two thrust ball bearings 9, and a flat key 22.

[0063] The ball screw 8 is translated axially in the cavity with the round holes at both ends of the inertial mass cavity as the guiding device; the ball nut 20 meshes with the thread on the screw through the balls 21 in the middle threaded part of the ball screw 8; the translation of the ball screw 8 is converted into the rotation of the ball nut 20 through the threaded part.

[0064] The mass flywheel 10 is connected to the ball nut 20 through a flat key 22 to rotate following the ball nut 20.

[0065] The two thrust ball bearings 9 are respectively located at both ends of the inertial mass cavity. The outer ring of the thrust ball bearing 9 is connected to the inner wall of the inertial mass cavity by interference fit, and the inner ring of the thrust ball bearing 9 contacts both ends of the mass flywheel 10 to fix the mass flywheel 10 and prevent the mass flywheel 10 from moving axially due to the axial force of the thread.

[0066] In this embodiment, the magnetorheological device part includes an inner piston, an outer piston 14, a guide 18, a coil 23, an airbag compensator 15, a Y-shaped sealing ring 19, and magnetorheological fluid 16.

[0067] A through hole for the inner piston rod 13 to pass through is provided at the end of the magnetorheological device cavity facing the inertial mass part. A groove is provided on the side wall of the cavity at the through hole for installing the Y-shaped sealing ring 19 to ensure the sealing of the magnetorheological device cavity.

[0068] The guide 18 is installed in the magnetorheological device cavity. The outer ring of the guide 18 fits with the inner wall of the magnetorheological device cavity. An interference fit connection is made between the inner ring at one end of the guide 18 and the inner piston rod 13 to ensure that the guide 18 reciprocates with the inner piston.

[0069] Both ends of the outer piston 14 are closely attached to the inner wall of the guide 18. The outer piston 14 is connected to the guides 18 on both sides by bolts to facilitate the outer piston 14 and the guide 18 to reciprocate together; the inner piston is located inside the outer piston 14.

[0070] The coil 23 is installed in the groove provided on the cylindrical surface of the inner piston. After the coil 23 is energized, a magnetic force circuit will be formed between the inner and outer pistons and the gap between them.

[0071] The magnetorheological fluid 16 fills the entire cavity except for the inner and outer pistons, the guide 18, the coil 23, and the airbag compensator 15. When the magnetorheological fluid 16 passes through the magnetic force circuit, its rheological properties change.

[0072] The bottom of the airbag compensator 15 is fixedly connected to the inner wall of the end of the magnetorheological device cavity far from the inertial mass part.

[0073] In this embodiment, the airbag compensator 15 is filled with nitrogen gas. When the inner and outer pistons reciprocate in the magnetorheological device cavity, the reciprocating movement of the inner piston rod 13 in and out of the cavity causes changes in the space inside the cavity, making it impossible for the magnetorheological fluid 16 to always fill the cylinder. In this case, the airbag compensator 15 eliminates the space changes caused by the piston movement by changing its own volume, ensuring that the magnetorheological fluid 16 always fills the cavity.

[0074] In this embodiment, the centers of the ball screw 8 and the inner piston rod 13 are both hollow. The two lead wires 7 at both ends of the coil 23 are led out of the cylindrical cylinder through the hollow parts of the inner piston rod 13 and the ball screw 8.

[0075] In this embodiment, the end of the inner piston rod 13 extending out of the magnetorheological device cavity is fixedly connected to one end of the ball screw 8 extending out of the inertial mass cavity through a coupling 12, ensuring that the inner piston rod 13 and the ball screw 8 reciprocate in the cylindrical cylinder simultaneously. The coupling 12 is located inside the coupling cavity.

[0076] In this embodiment, the MPC controller uses the MPC control algorithm to control the damping of the magnetorheological device, enabling the damping of the magnetorheological device to change in real time according to the current load. The specific design method of the MPC controller is as follows:

[0077] Step 1: Construct an MPC system prediction model through the kinematic differential equation of the offshore floating wind turbine system. Obtain the stiffness matrix K, mass matrix M, external load F, and initial damping matrix ci of the controlled system from the kinematic differential equation of the offshore floating wind turbine to construct the prediction model of the system. The equation of the MPC system prediction model is:

[0078]

[0079] In the formula and are the state change amount of the system and its first derivative respectively, y is the output change amount of the system. The state change amount of the system is defined by and M, K, and c i are the mass matrix, stiffness matrix, and initial damping matrix of the controlled system respectively, F is the external load of the controlled system; Δu represents the change amount of the system control input; the output change amount of the system is defined by C and D. Since the output of the system is the state change amount of the system, C is the identity matrix and D is the zero matrix. After discretization, the discrete prediction model of the system at the k-th moment is:

[0080]

[0081] Substitute the state change amount in formula (b - 2) and the output change amount y i(k), perform N-step iterative calculations, and convert the iterative formula into an equation expression in matrix form by parameter fitting:

[0082]

[0083] Where X k = [x(k|k) x(k + 1|k) … x(k + i|k) x(k + N|k)] T is the matrix set of all state change amounts x k+i within the prediction time domain at time k, Y k = [y(k|k) y(k + 1|k) … y(k + i|k) y(k + N|k)] T is the matrix set of all system output change amounts y k+i within the prediction time domain at time k, U k = [u s (k|k) u s (k + 1|k) … u s (k + i|k) u s (k + N - 1|k)] T is the matrix set of all system input change amounts y k+i within the prediction time domain at time k, L = [I A A 2 … A N T is the system state matrix set at each moment within the prediction time domain, W is the control input matrix set at each moment within the prediction time domain, is the system output matrix set at each moment within the prediction time domain, O = [0 I A 2 … A N T ;

[0084] Step 2, obtain the system state matrix set L, the control input matrix set W at each moment within the prediction time domain, the system output matrix set at each moment within the prediction time domain, and the matrix set X k+i of all state change amounts x k within the prediction time domain at time k, and some constant matrices; and use them to construct the objective function J(U k );

[0085] Construct an objective function based on the MPC system prediction model. The objective function J(U k ) of model predictive control is

[0086]

[0087] Where E K is the vector set of errors: ​​

[0088]

[0089] In the formula, [0] is a zero matrix, and U K is a set of vectors for controlling input changes, is a positive semi - definite symmetric time - varying matrix, is a positive definite symmetric time - varying matrix; Substitute E K into Equation b - 4 and combine with the equation to construct the objective function J(U k ) as

[0090]

[0091] In the formula and

[0092] Step 3, based on the objective function in Step 2, the parameters required for the quadratic programming algorithm are obtained, including the Hessian matrix the coefficient vector of the linear term of the objective function and the objective function J(U k ), and solve the change in the system control input Δu that minimizes the objective function through the quadratic programming algorithm, which is the change in the external control force ΔF;

[0093] Step 4, equivalently convert the change in the system control input Δu obtained in Step 3 into the change in the damping coefficient Δc of the magnetorheological damper, and add it to the damping coefficient c k-1 at the previous moment to obtain the system damping coefficient c k at the current moment. Use the damping coefficient c k as the damping coefficient of the wind turbine dynamics model at the current moment to solve the change in the state x k of the wind turbine system at the current moment. Finally, use it as the input of the system prediction model at the next moment, and iterate cyclically to obtain the changes in the system state at all moments.

[0094] The working process of the semi - active gyro mass damper system of the present invention is as follows:

[0095] When the tower of an offshore floating wind turbine vibrates under the action of wind and wave loads, the tuned mass block 3 starts to move laterally on the guide rail of the support frame 4 along with the tower. The movement of the tuned mass block 3 compresses the spring 1 and drives the semi-active gyro mass damper 2 to move. Due to the height difference at both ends of the semi-active gyro mass damper 2, an acceleration difference is generated at both ends. Among them, the ball screw 8 has a relative displacement with respect to the split cylinder block 5, and the translational motion of the ball screw 8 is converted into the rotational motion of the mass flywheel 10 by the ball nut 20. This conversion of the motion form will generate a huge force in the opposite direction of the motion, thereby consuming the energy of the controlled system. This phenomenon of generating a large force from a very small tuned mass is the mass amplification effect. The movement of the ball screw 8 will also be transmitted to the inner piston 13 through the coupling 12. The inner piston 13 and the outer piston 14 reciprocate in the cylinder block. During this process, the magnetorheological fluid 16 will generate a damping force through the gap between the piston 13 and the split cylinder block 5. At this time, the controller of the semi-active gyro mass damper system will adjust the current in the magnetorheological device coil 23 in real time based on the MPC control algorithm according to the external load to control the rheological characteristics of the magnetorheological fluid 16, thereby changing the damping force generated when the magnetorheological fluid 16 passes through the gap, and realizing semi-active control. This semi-active control obtains a better vibration suppression effect.

[0096] The present invention uses specific examples to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A semi-active gyroscopic mass damper system for vibration control of offshore floating wind turbine towers, characterized in that: including a semi-active gyroscopic mass damper assembly and an MPC controller for controlling damping; The semi-active gyro mass damper assembly structurally includes a tuning mass block, a spring, a semi-active gyro mass damper and a support frame; the support frame is a cantilever beam with one end fixedly connected to the wall of the wind turbine tower, and a sliding guide rail is arranged on the support frame in parallel along the front-rear direction of the wind turbine; the tuning mass block slides on the sliding guide rail of the support frame through a pulley arranged at the bottom thereof; the spring and the semi-active gyro mass damper are arranged in parallel; one end of the spring is fixedly connected to the wall of the wind turbine tower, and the other end is fixedly connected to the tuning mass block; the semi-active gyro mass damper includes an inertial mass part and a magnetorheological device part; one end of the semi-active gyro mass damper is fixedly connected to the mass block, and the other end is fixedly connected to a position on the wind turbine tower wall that is lower than the height of the semi-active gyro mass damper; The MPC controller mainly includes a system prediction module, an objective function construction module and an optimization solution module. The MPC controller is used to adjust the damping of the semi-active gyro mass damper in real time according to load changes during the operation of the offshore floating wind turbine.

2. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 1, characterized in that: Two sliding guide rails are arranged in parallel on the support frame along the front-rear direction of the fan, and the tuning mass block slides on the two sliding guide rails of the support frame through two sets of pulleys arranged at the bottom thereof.

3. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 2, characterized in that: The semi-active gyro mass damper comprises a split cylinder body, which is composed of two semi-cylindrical cylinder bodies connected by bolts and nuts to form a cylindrical cylinder body; the inner part of the cylindrical cylinder body is configured as an inertial mass cavity, a coupling cavity and a magnetorheological device cavity.

4. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 3, characterized in that: A groove is arranged on the cylinder wall of the matching surface of the two semi-cylindrical cylinder bodies for installing a sealing rubber ring, and the sealing rubber ring is used to realize the sealing of the internal cavity when the two semi-cylindrical cylinder bodies are connected to form a cylindrical cylinder body.

5. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 4, characterized in that: The inertial mass part includes a ball screw, a ball nut, a mass flywheel, balls, two thrust ball bearings and a flat key; The ball screw uses the circular holes at both ends of the inertial mass cavity as guide devices to translate in the axial direction of the cavity; the ball nut is meshed with the thread on the screw through the ball in the middle threaded portion of the ball screw; the translation of the ball screw is converted into rotation of the ball nut through the threaded portion; The mass flywheel is connected by a flat key and a ball nut to rotate with the ball nut; The two thrust ball bearings are respectively located at the two ends of the inertial mass cavity, the outer ring of the thrust ball bearing is connected with the inner wall of the inertial mass cavity by interference fit, and the inner ring of the thrust ball bearing is in contact with the two ends of the mass flywheel to fix the mass flywheel and prevent the mass flywheel from axially moving due to the axial force of the thread.

6. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 5, characterized in that: The magnetorheological device part includes an inner piston, an outer piston, a guide, a coil, an airbag compensator, a Y-shaped sealing ring and a magnetorheological fluid; A through hole for the inner piston rod to pass through is provided at the end of the cavity of the magnetorheological device facing the inertial mass part, and a groove is provided on the side wall of the cavity at the through hole for installing a Y-shaped sealing ring to ensure the sealing of the cavity of the magnetorheological device; The guide is installed in the cavity of the magnetorheological device, the outer ring of the guide is in contact with the inner wall of the cavity of the magnetorheological device, and the inner ring at one end of the guide is connected with the inner piston rod by interference fit to ensure that the guide reciprocates with the inner piston; The two ends of the outer piston are respectively close to the inner wall of the guide, and the outer piston is connected to the guides on both sides by bolts to facilitate the outer piston and the guide to reciprocate together; the inner piston is located inside the outer piston; The coil is installed in a groove arranged on the inner piston cylinder surface, and when energized, the coil forms a magnetic circuit between the inner and outer pistons and the gap between them; The magnetorheological fluid fills the entire cavity except for the inner and outer pistons, the guide, the coil and the airbag compensator, and the rheological properties of the magnetorheological fluid change when it passes through the magnetic circuit; The bottom of the airbag compensator is fixedly connected to the inner wall of the end of the magnetorheological device cavity away from the inertial mass part.

7. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 6, characterized in that: The airbag compensator is filled with nitrogen; when the inner and outer pistons reciprocate in the cavity of the magnetorheological device, the inner piston rod enters and exits the cavity, causing changes in the space in the cavity so that the magnetorheological fluid cannot always fill the cylinder body. The airbag compensator eliminates the space changes caused by the piston movement by changing its own volume, so that the magnetorheological fluid always fills the cavity.

8. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 7, characterized in that: The centers of the ball screw and the inner piston rod are both hollow, and both ends of the coil are led out of the cylindrical cylinder body through the hollow parts of the inner piston rod and the ball screw.

9. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 8, characterized in that: The end of the inner piston rod extending out of the magnetorheological device cavity is fixedly connected to one end of the ball screw extending out of the inertial mass cavity through a coupling to ensure that the inner piston rod and the ball screw simultaneously reciprocate in the cylindrical cylinder body; the coupling is located in the coupling cavity.

10. The semi-active gyroscopic mass damper system for offshore floating wind turbine tower vibration control according to claim 1, characterized in that: The MPC controller uses an MPC control algorithm to control the damping of the magnetorheological device, so that the damping of the magnetorheological device changes in real time according to the current load; the specific design method of the MPC controller is as follows; Step 1: construct an MPC system prediction model through the kinematic differential equation of the offshore floating wind turbine system. The MPC system prediction model equation is: In the formula and are the state change of the system and its first-order derivative, y is the output change of the system, and the state change of the system is given by and Definition, M, K and c i are the mass matrix, stiffness matrix and initial damping matrix of the controlled system respectively, and F is the external load of the controlled system; Δu represents the change in the system control input; since the system output is the change in the system state, C is the unit matrix; after discretization, the system prediction discrete model at the kth moment is: The state change of formula (b-2) and system output change y i (k), perform N steps of iterative calculation, and convert the iterative formula into a matrix equation expression for parameter fitting: Where, X k =[x(k|k) x(k+1|k)…x(k+i|k) x(k+N|k)] T For the prediction of all state changes x in the time domain at time k k+i The matrix set, Y k =[y(k|k) y(k+1|k)…y(k+i|k) y(k+N|k)] T The output change y of all systems in the predicted time domain at time k k+i The matrix set, U k =[u s (k|k)u s (k+1|k)…u s (k+i|k)u s (k+N-1|k)] T The predicted input change y of all systems in the time domain at time k k+i The matrix set, L = [IAA 2 …A N ] T is the system state matrix set at each moment in the prediction time domain, W is the control input matrix set at each moment in the prediction time domain, To predict the system output matrix set at each moment in the time domain, O = [0 IA 2 …A N ] T ; Step 2: construct an objective function based on the MPC system prediction model. The objective function J(U k )for Where E K is the vector set of errors: Where [0] is the zero matrix, U K is the vector set that controls the input changes, is a semi-positive symmetric time-varying matrix, is a positive definite symmetric time-varying matrix; E K Substitute into equation b-4 and construct the objective function J(U k )for In the formula and Step 3: Use the quadratic programming optimization algorithm to minimize the objective function to obtain the system control input change at the next moment. The control input is the change of the external input force. The change of the damping force ΔF c The change in the external control force ΔF is equivalent to the change in the damping force ΔF C To restrict: Since there is a direct relationship between the damping force and the damping coefficient of the controlled system, the change in damping force and the change in damping are converted: Step 4: Add the damping change obtained in step 3 to the damping of the system at the previous moment to obtain the system damping at the current moment; solve the damping coefficient at the current moment as the damping coefficient of the fan dynamics model to obtain the state change of the fan system at the current moment; Finally, the state change at the current moment is used as the input of the system prediction model at the next moment, and the damping change at all moments is obtained through iterative cycles.

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