Active control device and control method for oscillation suppression of offshore floating wind power system

Abstract

The application discloses a kind of offshore floating wind power system oscillation suppression active control device and control method, comprising: sensor, controller and actuator;Sensor is installed on the tower top and platform of offshore floating wind power system, sensor is used to collect tower top displacement acceleration and platform pitch angle acceleration data, and the obtained data is delivered to controller, one end of tower is connected with wind turbine cabin, and the other end is connected with the platform floating in the sea;Controller is used to calculate control force according to data, and generates offset signal to be sent to actuator according to the control force calculated;Actuator is used to exert control force on tuned mass damper TMD in wind turbine cabin according to offset signal, for keeping stable by controlling tuned mass damper TMD in wind turbine cabin Platform.Advantages: suitable for various offshore floating wind power systems, can be applied to various practical engineering systems, and has broad application prospect.

Description

TECHNICAL FIELD

[0001] The application relates to an active control device and a control method for oscillation suppression of a marine floating wind power system, and belongs to the technical field of marine wind power control. BACKGROUND

[0002] In recent decades, wind energy utilization and development have been widely and continuously developed at a high speed all over the world. Compared with traditional land wind turbines, deep sea wind energy resources are more abundant, and the space is less limited, which is an inevitable choice for future wind power industry development. Compared with fixed foundation wind turbines, the marine environment of floating offshore wind turbines is more complex, and the combined load of wind and wave will cause excessive vibration of the structure and cause large fatigue load at key parts such as the blade root and the tower root.

[0003] In view of the large load, two types of control methods are currently proposed. The first method is to change the rotor thrust to reduce the load by using the pitch control strategy, but the flexible foundation characteristics of the floating wind turbine determine that the platform motion frequency is very low, which leads to the possibility of negative damping of the traditional pitch control method. Another effective method to reduce the load is to use a passive or active control system for structural control, which has been successfully used in wind-resistant and anti-seismic civil structures and is considered to be a recommended strategy to extend the service life of wind turbines.

[0004] The most common passive structural control device is a tuned mass damper (TMD). The TMD passive control has the disadvantages of being too sensitive to fluctuations in the controlled frequency of the structure and poor robustness. Active control is proved to be more effective and stable, but current research only applies LQR and H∞ control algorithms to active controllers, and both methods require a linear simplified wind turbine model for control design. This paper attempts to utilize the vibration suppression potential of active control, proposes a more practical control method for industrial application, which does not require a linear simplified model and can be adjusted online to achieve better control effect. SUMMARY

[0005] The technical problem to be solved by the application is to overcome the defects of the prior art and provide an active control device and a control method for oscillation suppression of a marine floating wind power system, which can well overcome the adverse effects caused by the combined load of wind and wave during operation and ensure that the system maintains good stability under the control action of large load and multiple working conditions.

[0006] To solve the above technical problems, the application provides an active control device for oscillation suppression of a marine floating wind power system, which comprises a sensor, a controller and an actuator.

[0007] The sensor is installed on the top of the tower and the platform of the offshore floating wind power system, and is used to collect tower top displacement acceleration and platform pitch angle acceleration data and transmit the data to the controller.

[0008] The controller is used to calculate control force according to the data, and to generate a counter signal to the actuator according to the calculated control force.

[0009] The actuator is used to apply control force to the tuned mass damper (TMD) in the wind turbine nacelle according to the counter signal, and to control the platform to remain stable by controlling the tuned mass damper (TMD) in the wind turbine nacelle.

[0010] Further, the controller uses an NFC controller, which is a new type of basic controller.

[0011] A control method of an active control device for suppressing oscillation of an offshore floating wind power system, comprising:

[0012] According to the Kane dynamics theory, the Kane motion equation of the offshore floating wind turbine generator set is derived based on the mass, height, stiffness coefficient, damping coefficient, moment of inertia of the nacelle of the offshore floating wind power system and the mass, height, stiffness coefficient, damping coefficient, moment of inertia of the tower.

[0013] An elastic dynamics motion equation of a single degree of freedom HMD system is established based on the mass of the TMD mass block, the damping coefficient of the damper, the stiffness coefficient of the spring and the active control force applied in the HMD structure relative to the coordinate system of the ground.

[0014] The complete nonlinear time domain motion equation of the HMD coupled with the wind power system is derived in combination with the Kane motion equation and the elastic dynamics motion equation.

[0015] For the offshore floating wind power system studied, the dynamic response thereof is obtained in the FAST simulation software, the main motion mode of the offshore floating wind power system is calculated, the TMD stiffness coefficient is calculated according to the main motion mode of the offshore floating wind power system and the mass of the selected TMD mass block, and the TMD damping coefficient is obtained in combination with the system motion equation and the minimum cost function, thereby obtaining the TMD optimal parameters, and the TMD is a tuned mass damper.

[0016] The TMD parameters in the tuned mass damper (TMD) are set to the TMD optimal parameters to achieve the optimal passive control effect, and an acceleration feedback design NFC active controller is introduced.

[0017] According to the Z-N rule, the NFC controller parameters are set, the HMD optimal active control force is obtained, and the size of the HMD optimal active control force is transmitted to the actuator, and the actuator performs corresponding control.

[0018] Further, the complete nonlinear time-domain motion equation is expressed as:

[0019]

[0020] In the formula, M ij is the (i,j) component of the inertial mass matrix, which is nonlinearly dependent on the system degrees of freedom q, the control input u and the time t, is the second derivative of the degree of freedom j, f i is the component of the force function related to the degree of freedom i, is expressed as the first derivative of the degree of freedom j.

[0021] Further, the function of the NFC controller is:

[0022]

[0023] In the formula: G(s) represents the transfer function of the active control system, gain t and gain p are the RMS values of the signal tower top front and rear displacement and platform pitch angle, respectively, α is a variable parameter, α∈[0,1], NFC(s) represents the transfer function of the NFC controller, HPLO(s) represents the transfer function of the high-performance lead observer HPLO, and HPPI(s) represents the transfer function of the high-performance PI controller HPPI, and the HPPI and HPLO are connected in series to obtain a new type of basic controller NFC.

[0024] HPPI(s) is specifically defined as follows:

[0025]

[0026] In the formula: K HPPI is the external proportional gain of HPPI; the high-efficiency integrator HEI is constructed by ASWF, HEI(s) represents the transfer function of HEI, T HEI represents the HEI time constant, ASWF(s), T ASWF , n ASWF are the transfer function of ASWF, the approximate sliding window time length, and the integer order, respectively, β represents the order, and the complex variable s in the transfer function is the frequency response when the real part is zero and the imaginary part is the angular frequency;

[0027] HPLO(s) is specifically defined as follows:

[0028]

[0029] wherein: HPLO(s), T HPLO are transfer function, lead observation time constant of HPLO, respectively; HGPI is high gain PI controller, HGPI(s), K HGPI , T HGPI are transfer function, proportional gain, integral time constant of HGPI; LPF is low pass filter, LPF(s), T LPF are transfer function, filter time constant of LPF.

[0030] Further, the NFC controller parameter tuning according to Z-N rule is performed to obtain the HMD optimal active control force, comprising:

[0031] The NFC controller parameter tuning is performed on the following formula by using Z-N rule to obtain the relationship among ω PFB , ω PFB and T Z-N .

[0032]

[0033] wherein: T HPLO represents lead observation time constant, T HEI represents HEI time constant, K HPPI represents external proportional gain of HPPI, ω PFB is process frequency bandwidth, τ Z-N is process lag, T Z-N is process time constant, K Z-N is process gain;

[0034] The relationship among ω PFB , ω PFB and T Z-N is represented as:

[0035]

[0036] A computer readable storage medium storing one or more programs, the one or more programs comprising instructions which, when executed by a computing device, cause the computing device to perform any of the methods described.

[0037] A computer device comprising, one or more processors, memory and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs comprising instructions for performing any of the methods described. The present application achieves the beneficial effects that:

[0038] (1) Based on the acceleration information feedback and NFC control method, the nonlinear controller designed according to the controller design method given in the application will not lose the original information of the system in theory;

[0039] (2) The application is suitable for various offshore floating wind power systems, especially the barge type system with shallow overall draught and high gravity center, which will have large oscillation motion in deep sea and severe sea conditions, so the application can be applied to various actual engineering systems and has wide application prospect.

[0040] (3) The controller design method provided in the application does not require high theoretical knowledge and complex mathematical derivation, reduces the linearization model and parameter identification required for the design of the traditional controller such as the LQR controller, and is easy to implement in engineering. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a schematic diagram of a barge type offshore wind power system and an HMD active control system connection;

[0042] Figure 2 is a schematic diagram of an HMD active control system;

[0043] Figure 3 is a control block diagram of the HMD active control strategy of structural vibration;

[0044] Figure 4 is the power spectral density of the front and rear displacements of the tower top of the barge type wind power system;

[0045] Figure 5 Comparison chart of the front and rear displacements of the tower top of the barge type wind power system under no control, passive control and active control;

[0046] Figure 6 Comparison chart of the front and rear displacements of the tower top of the barge type wind power system under no control, passive control and active control;

[0047] Figure 7 Comparison chart of the platform pitch angle of the barge type wind power system under no control, passive control and active control;

[0048] Figure 8 Comparison chart of the platform pitch angle of the barge type wind power system under no control, passive control and active control;

[0049] Figure 9 is a control flowchart of the NFC controller. DETAILED DESCRIPTION

[0050] The application will be further described below in combination with the drawings. The following examples are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0051] The application discloses an active control method for suppressing oscillation of a marine floating wind power system, which comprises the following steps: firstly, based on Kane's dynamics theory, a general form of complete nonlinear time-domain motion equation of a system coupled with a wind turbine is derived by combining an elastic dynamic motion equation of a single-degree-of-freedom HMD system; then, TMD parameter optimization design is performed on the nonlinear model by minimizing a cost function; and finally, acceleration feedback is introduced and an NFC controller is used as a control core to realize an active structural vibration control system.

[0052] As shown in Figure 1 and 2 , the application discloses an active control device for suppressing oscillation of a marine floating wind power system, which comprises a sensor, a controller and an actuator.

[0053] The sensor is installed on a tower top and a platform of the marine floating wind power system, and is used for collecting tower top displacement acceleration and platform pitch angle acceleration data and transmitting the obtained data to the controller.

[0054] The controller is used for calculating a control force according to the data, generating a counteracting signal according to the calculated control force and sending the counteracting signal to the actuator.

[0055] The actuator is used for exerting a control force on a tuned mass damper (TMD) in a wind turbine cabin according to the counteracting signal, and is used for controlling the platform to be stable by controlling the TMD in the wind turbine cabin.

[0056] The controller adopts an NFC controller, and the NFC controller is a new type of basic controller.

[0057] As shown in Figure 9 , the method specifically comprises the following steps.

[0058] SS1 uses Kane's dynamics theory to derive a motion equation of the system according to existing literatures for a wind power system comprising P generalized coordinate systems, as shown in Figure 1 According to a direct result of Newton's motion law, Kane's motion equation of a simple complete system can be expressed as:

[0059] F i +F i * =0 (i=1,2,…,P)

[0060] For a W rigid body of a set of reference coordinate systems N r , a mass m r and a mass center position X r , a generalized driving force F iand the generalized inertial force F i * can be expressed as

[0061]

[0062] where, and represent the driving force and the moment of force at X r , respectively, represents the first derivative of the angular momentum of the rigid body at the center of mass point, represent the velocity, the acceleration and the angular velocity of the center of mass point, respectively.

[0063] The HMD control device is placed in the nacelle of the wind turbine. According to the established HMD motion equation, the complete nonlinear time-domain motion equation of the wind turbine and support platform coupling system can be derived, which is generally expressed as:

[0064]

[0065] where, M ij is the (i,j) component of the inertia mass matrix, which is nonlinearly dependent on the system degrees of freedom q, the control input u and the time t. is the second derivative of DOF j, f i is the component of the function of the force related to the degree of freedom i.

[0066] The elastic dynamics motion equation of the single-degree-of-freedom HMD system is established by using the coordinate system relative to the ground, which is expressed as:

[0067]

[0068] where, m, c and k are the mass, damping and stiffness coefficients of the wind turbine structure, respectively, m T , c T , k T are the mass, damping and stiffness coefficients of the HMD, respectively, x, are the displacement, velocity and acceleration of the wind turbine system relative to the ground, respectively, x T is the displacement of the HMD relative to the ground, F a (t) is the active driving force of the actuator of the HMD system, u H (t) is the resultant force of the HMD system acting on the wind turbine system, which can be expressed as

[0069]

[0070] SS3 combines the above equations to derive the general form of the complete nonlinear time-domain motion equations of the HMD coupled with the wind turbine system. These motion equations have the same general form as the complete nonlinear time-domain motion equations of the wind turbine coupled with the support platform system obtained by SS1, with the only difference being the additional degree of freedom brought by the HMD. Thus, the additional dynamics of the TMD system are coupled with the original motion equations of the wind turbine to obtain the true dynamic interaction between the TMD and the wind turbine structure.

[0071] SS4 selects the system important modes, Figure 4 two system modes, frequencies w j 0.54 Hz and 0.08 Hz, respectively. The parameter analysis of the HMD is as follows: open the TMD x DOF, where the initial displacement of the TMD is 0 m relative to the neutral reference position, set the mass to be relatively large, 20,000 kg, so that the natural frequency (w h ) of the HMD is the same as the natural frequency (w j ) of the dominant mode of the structure, and the value of k h is selected to be 5000 N m-1. Based on the selected m h and k h values, change the value of m h , and under the same initial conditions as when the structure is not subjected to structural control, simulate the system for 300 s of passive control until the cost function is minimized. Since the change in TTDspFA is closely related to the fatigue load in the tower, the cost function used is the standard deviation of the fore-aft displacement at the top of the tower, TTDspFA. The value of m h that minimizes this cost function is determined and marked as the optimal HMD parameter.

[0072] SS5, for the nonlinear model of the system, considering the limited effect of passive control, applies active control force to the nacelle TMD to form an HMD, and performs active and passive comprehensive control on the vibration response of the floating wind turbine. The HMD obtains the optimal control force by adopting a new type of basic controller (NFC). In the existing engineering method, an approximate sliding window filter (ASWF) is refined, which is used to construct a high-efficiency integrator (HEI) and a high-performance lead observer (HPLO). The high-performance PI controller HPPI obtained by HEI and HPLO are connected in series to obtain the new basic controller NFC, which significantly improves the feedback control performance, completely breaks away from the shackles of the model, has excellent robustness, simplicity and good engineering usability, and is suitable for complex offshore floating wind turbine models.

[0073] Figure 3 ​The basic block diagram of the control system, where the feedback signals are the platform pitch angle PtfmPitch and the tower top fore-aft displacement TTDspFA. The system mainly consists of a new type of foundation controller NFC, a FAST nonlinear wind turbine model, a variable parameter a and a fixed parameter gain for normalizing the signals t and gain p . Where the gains gain t and gain p are the RMS values of the signals TTDspFA and PtfmPitch respectively to make them dimensionless. And for the variable parameter a ∈ [0, 1], a = 0 corresponds to the platform pitch angle PtfmPitch feedback only, a = 1 corresponds to the tower top fore-aft displacement TTDspFA feedback only, and when a ∈ [0, 1], both feedbacks are used to calculate the active control force acting on the HMD.

[0074] The system transfer function is defined as follows:

[0075]

[0076] The NFC consists of a PI controller HPPI and a lead observer HPLO.

[0077] SS6 According to the engineers found that the Z-N rule is suitable for NFC controller parameter tuning, for high order inertia plus lag process, NFC parameter tuning principle is shown as follows, the principle avoids the cumbersome intermediate process such as model identification, model reduction, completely independent of the model.

[0078]

[0079] Where ω PFB is the process frequency bandwidth, τ Z-N is the process lag, T Z-N is the process time constant, K Z-N is the process gain.

[0080] Where HGLO(s), T HGLO are the transfer function of HPLO and the lead observation time constant respectively, HGPI is the high gain PI controller, LPF is the low pass filter. HGPI(s), K HGPI , T HGPI are the transfer function, proportional gain and integral time constant of HGPI. LPF(s), T LPF are the transfer function and filter time constant of LPF.

[0081] SS7 Simulates the suppression effect of TMD passive control and HMD comprehensive control on the dynamic response of barge type floating wind turbine under wind and wave combined load. As Figure 5 , 6, 7, 8 are respectively TTDspFA, PtfmPitch contrast chart of wind turbine tower top front and back displacement under three kinds of control conditions when TMD mass stroke limit is ±10m, wherein Figure 5 is TTDspFA amplitude contrast chart, Figure 6 is TTDspFA PSD energy contrast chart, Figure 7 is PtfmPitch amplitude contrast chart, Figure 8 is PtfmPitch PSD energy contrast chart.From the PSD chart of each index, it can be seen that some larger peaks are concentrated between 0.06-0.14Hz, and the frequency of these peaks is close to 0.08Hz, which is the peak spectrum frequency. TMD passive control and HMD comprehensive control can significantly reduce these peaks, and HMD comprehensive control can also reduce more peaks. Combined with the changes of tower top vibration displacement and platform pitch angle, it can be concluded that the structural control system can effectively suppress the vibration of wind turbine. Most importantly, NFC control can achieve greater load reduction and vibration reduction effect than TMD passive control, indicating that the designed HMD active controller has a certain reliability.

[0082] The whole work flow chart is shown in Figure 9 .

[0083] Correspondingly, the application also provides a computer readable storage medium storing one or more programs, the one or more programs including instructions which, when executed by a computing device, cause the computing device to perform any of the methods.

[0084] Correspondingly, the application also provides a computer device, including one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include instructions for executing any of the methods.

[0085] Those skilled in the art will understand that embodiments of the application can be provided as methods, systems, or computer program products. Therefore, the application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the application can take the form of a computer program product implemented on one or more computer usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0086] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0087] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0088] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flow or blocks. Figure 1 one or more flow or blocks.

[0089] The above only is the preferred embodiment of the present application, it should be pointed out that, for those skilled in the technical field, without departing from the technical principles of the present application, can also make a number of improvements and variations, these improvements and variations should also be considered as the protection scope of the present application.

Claims

1. A control method for an active control device for offshore floating wind power system oscillation suppression, the active control device comprising: The sensor, the controller and the actuator; The sensor is installed on the top of the tower and the platform of the offshore floating wind power system, and is used to collect tower top displacement acceleration and platform pitch angle acceleration data and transmit the data to the controller, one end of the tower is connected with a wind turbine cabin, and the other end is connected with the offshore floating platform; The controller is used for calculating control force according to the data, generating a counter signal according to the calculated control force and sending the counter signal to the actuator; The actuator is used for applying control force to the tuned mass damper (TMD) in the wind turbine cabin according to the counter signal, and is used for controlling the platform to remain stable by controlling the tuned mass damper (TMD) in the wind turbine cabin; The controller adopts an NFC controller, and the NFC controller is a new type of basic controller It is characterized by comprising: According to the Kane dynamics theory, the Kane motion equation of the offshore floating wind turbine is derived based on the mass, height, stiffness coefficient, damping coefficient, moment of inertia of the wind turbine cabin and the mass, height, stiffness coefficient, damping coefficient and moment of inertia of the tower; An elastic dynamics motion equation of a single degree of freedom HMD system is established based on the mass of the TMD mass block, the damping coefficient of the damper, the stiffness coefficient of the spring and the active control force applied in the HMD structure relative to the ground coordinate system; The complete nonlinear time domain motion equation of the HMD coupled with the wind power system is derived by combining the Kane motion equation and the elastic dynamics motion equation; For the offshore floating wind power system studied, the dynamic response thereof is obtained in the FAST simulation software, the main motion mode of the offshore floating wind power system is calculated, the TMD stiffness coefficient is calculated according to the main motion mode of the offshore floating wind power system and the mass of the selected TMD mass block, and the TMD damping coefficient is obtained by combining the system motion equation and the minimum cost function, so as to obtain the TMD optimal parameters, and the TMD is a tuned mass damper; The TMD parameters in the tuned mass damper (TMD) are set as the TMD optimal parameters, and an acceleration feedback design NFC active controller is introduced; The NFC controller parameters are tuned according to the Z-N rule, the HMD optimal active control force is obtained, the size of the HMD optimal active control force is transmitted to the actuator, and the actuator performs corresponding control; The function of the NFC controller is: ； wherein: G(s) G (s) represents the transfer function of the active control system, gain t and gain p respectively the RMS value of the signal normalized to the top front and back displacement of the tower and the pitch angle of the platform, α is a variable parameter, α ∈ [0, 1], NFC(s) G (s) represents the transfer function of the NFC controller, HPLO(s) G (s) represents the transfer function of the high performance lead observer HPLO, HPPI(s) G (s) represents the transfer function of the high performance PI controller HPPI, the series of HPPI and HPLO gives a new type of basic controller NFC; HPPI(s) is specifically defined as follows: ； where: K HPPI is the outer proportional gain for HPPI; the high-efficiency integrator HEI is constructed from ASWF, HEI s represents the transfer function of HEI, T HEI represents the time constant of HEI, ASWF s , T ASWF , n ASWF are the transfer function of ASWF, the approximate sliding window time length, and the integer order, respectively, β represents the order, and the complex variable in the transfer function s is the frequency response when the real part is zero and the imaginary part is the angular frequency.​​ HPLO(s) is specifically defined as follows: ; wherein: HPLO s T HPLO HGPI is a high gain PI controller, HPLI s K HGPI T HGPI HGPI is a high gain PI controller, T LPF LPF is a low pass filter, and LPF(s) is a transfer function of the LPF, a filter time constant.​​​​​ 2. The control method of the active control device for suppressing oscillation of an offshore floating wind power system according to claim 1, characterized by, The complete nonlinear time domain motion equation is represented as: ； In the formula, M ij It is the inertial mass matrix ( i , j This component is nonlinearly dependent on the system's degrees of freedom. q Control input u and time t , For degrees of freedom j The second derivative, f i Is it related to degrees of freedom? i The components of the relevant force function, Represented as degrees of freedom j The first derivative.

3. The control method of the active control device for suppressing oscillation of an offshore floating wind power system according to claim 1, characterized by, The NFC controller parameters are tuned according to the Z-N rule, the HMD optimal active control force is obtained, and includes: The NFC controller parameters of the following formula are tuned by using Z-N rule to obtain The relationship between and ； wherein: T HPLO represents a lead time constant, T HEI represents an HEI time constant, K HPPI represents an outer proportional gain of the HPPI, is a process frequency bandwidth, is a process lag, is a process time constant, is a process gain; The The relationship between is 。 4. A computer-readable storage medium storing one or more programs, the one or more programs comprising instructions that when executed by a computer cause the computer to perform a method comprising: The one or more programs include instructions that, when executed by a computing device, cause the computing device to perform any of the methods of claims 1-3.

5. A computer device, comprising: including, One or more processors, memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods of claims 1-3.

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