CN110134015B - H-infinity robust control method for hydraulic variable pitch system of wind turbine generator - Google Patents

H-infinity robust control method for hydraulic variable pitch system of wind turbine generator Download PDF

Info

Publication number
CN110134015B
CN110134015B CN201910410510.9A CN201910410510A CN110134015B CN 110134015 B CN110134015 B CN 110134015B CN 201910410510 A CN201910410510 A CN 201910410510A CN 110134015 B CN110134015 B CN 110134015B
Authority
CN
China
Prior art keywords
hydraulic
function
pitch system
variable pitch
proportional
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910410510.9A
Other languages
Chinese (zh)
Other versions
CN110134015A (en
Inventor
王冰
王绍平
沈王平
陈桂儒
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hohai University HHU
Original Assignee
Hohai University HHU
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hohai University HHU filed Critical Hohai University HHU
Priority to CN201910410510.9A priority Critical patent/CN110134015B/en
Publication of CN110134015A publication Critical patent/CN110134015A/en
Application granted granted Critical
Publication of CN110134015B publication Critical patent/CN110134015B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B13/00—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion
    • G05B13/02—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric
    • G05B13/04—Adaptive control systems, i.e. systems automatically adjusting themselves to have a performance which is optimum according to some preassigned criterion electric involving the use of models or simulators

Abstract

The invention discloses an H infinity robust control method of a hydraulic variable pitch system of a wind turbine generator, which comprises the following steps of firstly, solving a mathematical model of the hydraulic variable pitch system, and rewriting the mathematical model into a state equation of a nominal object; selecting a weighting function which meets the system requirement in the process of mixed sensitivity optimization according to the system performance requirement, and further obtaining the state space realization of the generalized controlled object of the system; then, the H-infinity controller is solved through a hinf function in a robust control tool kit in Matlab softwareK(s) And an H infinity controllerK(s) The hydraulic pitch control system is used in a hydraulic pitch control system. The hydraulic variable pitch control method provided by the invention has strong practicability, reduces the operation error and has good control effect on external interference and the change of self parameters. When the internal parameters of the hydraulic variable pitch system are gradually changed for a long time or are interfered by the external environment, the robust anti-interference performance of the controlled hydraulic variable pitch can be improved by the H-infinity control method.

Description

H-infinity robust control method for hydraulic variable pitch system of wind turbine generator
Technical Field
The invention relates to an H infinity robust control method of a hydraulic variable pitch system of a wind turbine generator, belonging to the technical field of hydraulic variable pitch control.
Background
With the urgent need of traditional fossil energy and the deterioration of global environment, wind energy has attracted attention as a clean and pollution-free renewable energy source. With the rapid development of the wind power industry, the research on the wind power generation technology is also highly regarded. In a wind turbine generator control system, a hydraulic variable pitch system is one of core components of a variable-speed constant-frequency wind turbine generator, and plays an important role in safe and stable operation of the system. The hydraulic variable pitch system changes the lift force of the airfoil of the blade by rotating the pitch angle of the blade through a bearing mechanism between the blade and the hub, thereby changing the aerodynamic characteristics of the blade and adjusting the stress conditions of the blade and the whole machine.
Although some traditional control strategies can realize better control over the hydraulic variable pitch system, influence of factors such as uncertainty brought by parameters of a model and external interference on system performance is not fully considered, H infinity robust control is used as an important method of a modern robust control theory, the variable pitch system can be effectively tracked, the variable pitch mechanism can be kept stable under the condition that the parameters are uncertain and the external interference exists, and the robustness of the system is enhanced.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the H-infinity robust control method for the hydraulic variable pitch system of the wind turbine generator has a good control effect on the condition of gradual change of a parameter structure caused by long-term external severe environment and internal abrasion.
The invention adopts the following technical scheme for solving the technical problems:
an H infinity robust control method of a hydraulic variable pitch system of a wind turbine generator comprises the following steps:
step 1, solving a transfer function of the hydraulic variable pitch system according to a model of the hydraulic variable pitch system, wherein the model comprises a flow equation of an electro-hydraulic proportional reversing valve, a flow continuity equation of a hydraulic cylinder, a stress equation of the hydraulic cylinder and a stress balance equation of an electro-hydraulic proportional pilot valve;
step 2, applying the H-infinity robust control to the hydraulic variable pitch system to obtain three closed loop transfer functions of input to tracking error, input voltage and actual output of the hydraulic variable pitch system after the H-infinity robust control;
step 3, selecting a weighting function, converting the H infinity robust control problem into a mixed sensitivity optimization problem, and solving a generalized controlled object of the hydraulic variable pitch system under the mixed sensitivity optimization problem according to the three closed-loop transfer functions in the step 2;
and 4, deducing a state space equation of the generalized controlled object of the hydraulic pitch system according to the generalized controlled object and the weighting function in the step 3, and solving the H-infinity controller K(s) by a hinf function in the Matlab robust control tool box.
As a preferred scheme of the present invention, the specific process of step 1 is:
step 1.1, the flow equation of the electro-hydraulic proportional directional valve is as follows:
Qm＝λmxv-λnPm
wherein Q ismM is the flow of the electro-hydraulic proportional reversing valve3/s；λmAs an amplification factor of the flow, m2/s；xvThe displacement is mm of a valve core of the proportional direction valve; lambda [ alpha ]nAs a flow-pressure amplification factor, m5/N·s；PmIs the load pressure of the proportional valve, N;
step 1.2, the hydraulic cylinder flow continuity equation is as follows:
Figure BDA0002062669490000021
wherein A ismIs the area of the piston of the hydraulic cylinder in cm2；ymIs the displacement of the piston of the hydraulic cylinder, mm; t represents time, V0Total volume of hydraulic pressure, m3；βcIs the volume elastic coefficient of the hydraulic cylinder; cmIs the leakage coefficient;
step 1.3, the stress equation of the hydraulic cylinder is as follows:
Figure BDA0002062669490000022
wherein m is the total mass of the piston and the load, kg; b isQA viscous damping coefficient for piston and load motion; mu is the force coefficient born by the loaded spring; fQIs the force applied by the load disturbance, N;
step 1.4, the stress balance equation of the electro-hydraulic proportional pilot valve is as follows:
Figure BDA0002062669490000031
wherein i is proportional electromagnet input current, mA; ksfThe spring stiffness, N.m/rad, is detected for the feedback of the electro-hydraulic proportional pilot valve; kiIs a proportional electromagnet force-current amplification factor, N/mA; kbVoltage displacement amplification factor, mA/mm;
step 1.5, the transfer function of the hydraulic pitch control system obtained from steps 1.1-1.4 is:
Figure BDA0002062669490000032
wherein G is0(s) represents a transfer function of the hydraulic pitch system; ktThe electro-hydraulic proportional amplification factor; kmIs a feedback control coefficient, mA/mm; s is a parameter of the transfer function.
As a preferred embodiment of the present invention, the closed-loop transfer function in step 2 satisfies:
Figure BDA0002062669490000033
wherein S is a sensitivity function; r, T is a complementary sensitivity function; i is a unit transfer function; k(s) is a hydraulic variable pitch system controller; g(s) is a generalized controlled object of the hydraulic variable pitch system; s is a parameter of the transfer function.
As a preferred embodiment of the present invention, the weighting function in step 3 is:
W1＝180/(25s+1),W2＝0.008,W3＝(10s+32)/320
wherein, W1Is a weighted function of the sensitivity function S; w2Is a weighted function of the complementary sensitivity function R; w3Is a weighted function of the complementary sensitivity function T; s is a parameter of the transfer function.
As a preferred solution of the present invention, the generalized controlled objects of the hydraulic pitch control system in step 3 under the hybrid sensitivity optimization problem are:
Figure BDA0002062669490000034
wherein z is1An evaluation signal for externally inputting r to a tracking error e; z is a radical of2An evaluation signal for an external input r to a system input u; z is a radical of3An evaluation signal for external input r to actual output y; w1Is a weighted function of the sensitivity function S; w2Is a weighted function of the complementary sensitivity function R; w3Is a weighted function of the complementary sensitivity function T; i is a unit transfer function; g(s) is a generalized controlled object of the hydraulic variable pitch system; s is a parameter of the transfer function; d is external disturbance; pnIs a generalized controlled-pair matrix of a hydraulic pitch system.
As a preferred solution of the present invention, the state space equation of the generalized controlled object of the hydraulic pitch system in step 4 is:
Figure BDA0002062669490000041
wherein the content of the first and second substances,
Figure BDA0002062669490000042
Figure BDA0002062669490000043
[x0,x1,x2,x3]-Tis a state variable of the hydraulic variable pitch system; z is a radical of1An evaluation signal for externally inputting r to a tracking error e; z is a radical of2An evaluation signal for an external input r to a system input u; z is a radical of3An evaluation signal for external input r to actual output y; w1Is a weighted function of the sensitivity function S; w2Is a weighted function of the complementary sensitivity function R; w3Is a weighted function of the complementary sensitivity function T;
Figure BDA0002062669490000044
final output for the control object; ktThe electro-hydraulic proportional amplification factor; kmIs a feedback control coefficient, mA/mm; i is a unit transfer function; d is external disturbance; a. then1、Bn1、Cn1、Dn1Is W1Of (A) ann2、Bn2、Cn2、Dn2Is W2Of (A) ann3、Bn3、Cn3、Dn3Is W3Of (2) is used.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
1. aiming at parameter uncertainty and external interference existing in a variable pitch system of a wind turbine generator, the invention designs an H infinity robust controller, and improves the dynamic performance and stability margin of a closed-loop system.
2. The hydraulic variable pitch control method provided by the invention has strong practicability, reduces the operation error and has good control effect on external interference and the change of self parameters.
Drawings
FIG. 1 is a schematic view of a hydraulic pitch system according to the present invention.
Fig. 2 is a diagram of the H ∞ robust control of the hydraulic pitch actuator.
FIG. 3 is a graph of a standard H ∞ robust control problem.
FIG. 4 is a graph of the problem of mixed sensitivity optimization.
FIG. 5 is a MATLAB diagram of a hydraulic variable pitch system of a wind turbine generator with an H-infinity stick controller, wherein (a) is a dynamic response, (b) is a root locus, (c) is a Nyquist curve, and (d) is a bode diagram.
FIG. 6 is a MATLAB graph with gradual changes in its own parameters, where (a) is the response curve and (b) is the bode graph.
FIG. 7 is an external disturbance map of the hydraulic pitch system.
FIG. 8 is a graph showing a comparison of pitch angle simulations for three cases, without any controllers added, with an H ∞ robust controller added, and with a PI controller added.
Fig. 9 is a pitch angle bode comparison diagram of the PI control and the H ∞ control.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.
The invention provides an H infinity robust control method of a hydraulic variable pitch system of a wind turbine generator, which comprises the following steps:
step 1: modeling of hydraulic variable pitch control system
Step 101, a flow equation of the electro-hydraulic proportional directional valve:
Qm＝λmxv-λnPm (1)
wherein Q ismProportional valve flow, m3/s；λmAmplification factor of the flow, m2/s；λnFlow-pressure amplification factor, m5/N·s；Pm-load pressure of the proportional valve, N; x is the number ofvProportional directional valve spool displacement, mm.
102, a hydraulic cylinder flow continuity equation:
Figure BDA0002062669490000051
wherein A ismArea of piston of hydraulic cylinder, cm2；V0Total volume of hydraulic pressure, m3；βc-the volumetric elastic coefficient of the hydraulic cylinder; y ism-hydraulic cylinder piston displacement, mm; cm-leakage factor.
Step 103, a stress equation of the hydraulic cylinder:
Figure BDA0002062669490000061
wherein m is the total mass of the piston and the loadAmount, kg; b isQ-viscous damping coefficient of piston and load motion; fQ-the force applied by the load disturbance, N; mu-the force coefficient experienced by the loaded spring.
Step 104, a stress balance equation of the electro-hydraulic proportional pilot valve:
Figure BDA0002062669490000062
wherein, i is the input current of the proportional electromagnet, mA; ki-proportional electromagnet force-current amplification factor, N/mA; ksf-proportional reversing pilot valve feedback detection spring stiffness, N · m/rad; kb-voltage displacement amplification factor, mA/mm.
Step 105, obtaining a transfer function of the hydraulic pitch system from (1) to (4):
Figure BDA0002062669490000063
in the formula of alphat-hydraulic natural frequency; xit-hydraulic system damping ratio; km-feedback control factor, mA/mm; kvHydraulic cylinder piston velocity amplification factor, m2/cm2S, and Kv＝λm/Am，Kt＝Kv/Kb；Kt-electro-hydraulic proportional amplification factor. Due to the natural frequency alpha of the hydraulic pitch systemtFar greater than damping ratio xi of hydraulic systemtThe above formula can be simplified as:
Figure BDA0002062669490000064
step 2: in the hydraulic variable pitch system, parameters of an internal system are uncertain due to long-time operation, certain errors are formed in system modeling, and external interference brings adverse factors to stable operation of the variable pitch system. In order to ensure that the pitch system is able to effectively suppress disturbances with uncertainty, the hydraulic pitch system is here controlled H ∞ and comprises the following steps:
step 201, the H infinity robust control is used for the hydraulic pitch system. According to the standard H infinity robust control criterion, the standard H infinity robust control generalized controlled object can be obtained as follows:
Figure BDA0002062669490000071
and obtaining a transfer function G(s) after H ∞ robust control as:
Figure BDA0002062669490000072
wherein z is an evaluation signal output by the variable pitch system; y is an actual measurement value of the variable pitch angle; d is the interference of the external environment; u is the input voltage of the system; g(s) is a generalized controlled object of the pitch system.
Thus, the closed-loop transfer function of the disturbance d of the standard H ∞ robust control to the evaluation output z is:
Hzw(s)＝G11(s)+G12(s)K(s)[I-G22(s)K(s)]-1G21(s) (9)
where K(s) is the pitch system controller of the desired design.
Step 202, mix the standard model of the sensitivity problem. The problem of hybrid sensitivity is one of the most typical problems of H-infinity control, and when an H-infinity method is applied to design a system, in order to ensure the robust performance of the system, the H-infinity robust control problem is generally designed and converted into the problem of hybrid sensitivity optimization, so that not only is the effective inhibition of a controller on external interference considered, but also the influence of a variable pitch model on the variability of parameters of the variable pitch model is considered. From the standard mixed sensitivity optimization problem, W can be set1The performance weighting function reflects the interference characteristics of external environment factors on the variable pitch system; w2Outputting a weighting function for the controller, representing a voltage threshold limit controllable for the system itself; w3The weight value is the robust weight value of the system; e is the tracking error(ii) a r is an external input. Where the closed loop transfer function of r to e, u, and y is S, R, T. Satisfies the following conditions:
Figure BDA0002062669490000073
where S is the sensitivity function, R, T is the complementary sensitivity function, and I is the unit transfer function. S represents the requirement for controlling the system performance, and R and T represent the requirement for robust stability of the system.
External environmental disturbances d to z1、z2、z3The transfer function is:
Figure BDA0002062669490000074
wherein z is1An evaluation signal for externally inputting r to a tracking error e; z is a radical of2An evaluation signal for an external input r to a system input u; z is a radical of3Is an evaluation signal from an external input r to an actual output y.
In order to ensure that the hydraulic pitch control system can effectively suppress disturbance under the uncertain condition, two conditions are required to be met: 1) finding a real rational function controller K(s); 2) the hydraulic variable pitch system keeps the norm minimization of the transfer function matrix in a certain range.
Step 203, the generalized controlled objects of the hydraulic pitch system under the standard-based hybrid sensitivity problem obtained from steps 201 and 202 are:
Figure BDA0002062669490000081
in the formula, PnIs a generalized controlled-pair matrix of a hydraulic pitch system.
And step 3: state space implementation of generalized controlled object
Step 301, selecting criteria for weighting function, where we select three weighting functions W that satisfy the system requirements1、W2、W3。
W1Is a weighting function for the sensitivity function S, is used to shape the S function, is a transfer function of the reference input to the tracking error, and is also a transfer function of the interference input to the system output. Due to the requirements of rapidness and accuracy of the variable pitch in actual operation, W is enabled to be1The system needs larger gain at low frequency, so that not only can the pitch angle be accurately tracked more quickly, but also the noise interference can be effectively inhibited. So that the weighting function W1Is a low pass transfer function. Obtaining W through simulation comparison1＝180/(25s+1)。
W2Is a weighted function of the compensation sensitivity R, representing the norm bound of the additive perturbation, which is a perturbation range decision of system parameters used to constrain the output of the designed hydraulic pitch controller. In order to prevent the damage to the system caused by the overload generated in the operation of the pitch system, the input current of the controller needs to be controlled to a certain degree, and in the design of mixed sensitivity, the weighting matrix W can be selected2To achieve an estimation of the control signal amplitude range; in a mixed sensitivity design, the weighting matrix W can be selected2To enable estimation of the control signal amplitude range. Usually take W2Is constant, and W is preferably chosen to ensure that the hydraulic pitch system is within a controllable range2＝0.008。
W3The method is a weighting function for T, represents a norm boundary of multiplicative perturbation and reflects the requirement of robust stability performance. W3The method has the advantages that the method has high-pass property, the change range of the hydraulic variable pitch system to the parameters can be well reflected, and the dynamic characteristics in modeling can be reflected. W3At high frequencies of the pitch angle, there is a certain attenuation of the singular values of T, and for hydraulic pitch systems, W3The amplitude margin, the phase angle margin and the larger bandwidth which are met by the system can be provided, and the variable pitch system can better adapt to the variability of external interference. Through simulation practice, selecting W3＝(10s+32)/320。
Step 302, solving the state space equation of the generalized controlled object of hydraulic pitch control
1) According to the description of the standard mixed sensitivity optimization problem, the state space realization equation matrix of the output of the hydraulic variable pitch system can be calculated as
Figure BDA0002062669490000091
2) Hydraulic pitch angle actual output expression
Figure BDA0002062669490000092
In the formula (I), the compound is shown in the specification,
Figure BDA0002062669490000096
final output of the control object; d is the external disturbance.
3) State space implementation of three weighting functions. The three weighting functions W obtained above are combined1、W2、W3Performing state space realization to obtain a state space realization equation matrix of three weighting functions
Figure BDA0002062669490000093
4) The state space expression of the evaluation signal z of the hydraulic variable pitch is
Figure BDA0002062669490000094
And step 303, realizing the state space of the generalized controlled object. The state space equation of the generalized controlled object of the hydraulic pitch system obtained by the equations (13), (14) and (16):
Figure BDA0002062669490000095
in the formula [ x0,x1,x2,x3]-TThe state variable of the hydraulic variable pitch system is obtained; and I is a unit array.
And 4, step 4: design of controller K(s)
The method calculates K after the starting of the propeller-opening process according to the data of the 1.5MW unit provided by a certain coastal wind power plantt＝9.876、KmSubstituting the state space equation model into a state space equation model of a hydraulic variable pitch generalized controlled object, solving through a hinf function in a robust control tool kit in Matlab software to obtain a controller which meets the system requirement
Figure BDA0002062669490000101
And the system is added into a control system of the hydraulic variable pitch, and the superiority of a control strategy is verified through simulation.
To better illustrate the solution of the present invention, the system is modeled in Matlab and described with reference to the accompanying drawings.
Fig. 1 is a schematic view of a hydraulic pitch system. The hydraulic variable pitch system of the wind turbine is an automatic control system and comprises a variable pitch controller, a D/A converter, a proportional reversing valve, a hydraulic cylinder, a crank connecting structure, a displacement sensor, blades and the like, and the structure of the variable pitch system is as shown in the following figure: the proportional reversing valve, the hydraulic cylinder and the crank connecting structure are actuating mechanisms of a variable pitch control system, the variable pitch control system converts signals input by a controller and a D/A converter system into analog quantity, and the actuating mechanisms control the pitch angles of the blades; the feedback system feeds back actually measured pitch angle signals to a system pitch controller through an A/D converter by an arranged displacement sensor, compares the actually measured pitch angle signals with actually responded measured values given by the pitch angle to form deviation, and adjusts the control signals according to the deviation value of the pitch angle, so that a variable pitch closed-loop system is formed. The hydraulic variable pitch system uses hydraulic pressure to drive an actuating mechanism to change the pitch angle of the blade, and the specific control mode is as follows: when v isWind speed<vRated wind speedThe electro-hydraulic proportional reversing valve maintains the pitch angle of the blades to be 0 degree; when v isWind speed≥vRated wind speedThe controller controls the pitch angle of the blades by reversing the direction and the magnitude of the output flow of the valve, so that the power output is kept constant.When the proportional valve is electrified to the left, pressure oil enters the front end of the cylinder barrel, the piston rod moves leftwards, the pitch angle is reduced, the piston rod moves leftwards to the maximum position, and the pitch angle beta is 0 degree; when the proportional valve is electrified to the right, pressure oil enters the rear end of the cylinder barrel, the piston rod moves rightwards, the pitch angle is increased, the piston rod moves rightwards to the maximum position, and the pitch angle beta is equal to 90 degrees.
FIG. 2 is a graph of the H ∞ robust control of the hydraulic pitch actuator. In the hydraulic variable pitch system, due to the fact that the abrasion of an internal system causes uncertainty factors of parameters of the hydraulic variable pitch system, certain errors can be formed in system modeling, and external interference can bring adverse factors to the stable operation of the hydraulic variable pitch system. To ensure that the pitch system is able to effectively suppress disturbances under uncertain conditions, the controller is therefore designed to have robust stability.
FIG. 3 is a standard H ∞ robust control problem: z is an evaluation signal output by the variable pitch system; y is an actual measurement value of the variable pitch angle; d interference of the external environment; u is the input voltage of the system; g(s) is a generalized controlled object of the variable pitch system; k(s) is a pitch system controller of a desired design.
FIG. 4 the lower graph is a standard model of the mixed sensitivity problem: wherein, W1The performance weighting function reflects the interference characteristics of external environment factors on the variable pitch system; w2Outputting a weighting function for the controller, representing a voltage threshold limit controllable for the system itself; w3The weight value is the robust weight value of the system; e is the tracking error; r is an external input.
Fig. 5 (a), (b), (c), and (d) are dynamic response curves, root trajectories, Nyquist curves, and bode plots that are added to the controller based on the H ∞ robust control strategy of the wind turbine hydraulic pitch system. It can be seen from fig. 5 (a) that the system rise time is significantly shortened, the steady state value is reached at 0.4s, and the system has no overshoot during operation, and the dynamic performance of the pitch control system is significantly improved. It can be seen from fig. 5 (b) that when the system changes from zero to infinity, the root locus curves are all located in the left plane of S, and the pole of the system is located at the left half axis of the S axis, the system is stable. From (c) of fig. 5, it can be seen that the number of open-loop poles of the system in the right half-plane S is 0, and the number of turns of Nyquist curve around (-1,0j) is 0, so that the control system is stable. It can be seen from the (d) bode diagram of fig. 5 that the gain of the low frequency is increased after the controller is added, and the cut-off frequency, the phase angle margin and the bandwidth of the system are all increased significantly. This shows that the system not only ensures dynamic performance and certain tracking accuracy, but also enhances the robustness of the system.
FIG. 6 (a) and (b) are 0.85G0(s)、G0(s)、1.15G0Response curves and bode plots for case(s). In actual operation, some parameters of the hydraulic pitch system may be subject to gradual changes due to aging, fatigue, wear, etc. Researches show that parameters such as proportional electromagnetic force current amplification coefficient, flow amplification coefficient, proportional direction pilot valve feedback detection spring rigidity and the like can be changed due to looseness of oil level gauge pipelines, damage of parts, rusting of blades and faults of a displacement sensor, and finally hydraulic variable pitch electro-hydraulic proportional amplification coefficient K in a model can be influencedtFeedback control coefficient Km. The displacement of the piston cylinder of the input current and output of the transfer function is suitably changed to change the magnitude of the transfer function, so that the cut-off frequency omega of the transfer function of the hydraulic pitch model is changedcWithin 15%, i.e. the system transfer function is 0.85G0(s)～1.15G0(s) are varied. When the influence range of the system on the change of the model parameters is +/-15%, the cut-off frequency omega obtained by adding a robust controller into the system is obtained through dynamic tracking and bode simulation of the pitch angle of the hydraulic variable propellercAnd a phase angle margin γ. The analysis chart shows that: the final regulation time of the dynamic curve is not changed greatly, overshoot does not occur, and the cut-off frequency omega of the variable pitch systemcThe power supply is changed between 6.52rad/s and 8.74rad/s and is kept within the range of-14% to + 14% of the power supply, and the designed controller can better adapt to the uncertainty of the parameters of the power supply. The results show that the H-infinity controller enables the hydraulic pitch system to control within its own standard range when its own model parameters are uncertain.
Fig. 7 and 8 are external disturbance diagrams of the hydraulic pitch system and pitch angle comparison diagrams in three cases, respectively. When the model parameters are accurate and external disturbances such as external wind speed, temperature and climate are received, in order to verify the interference suppression effect of a robust controller of the designed system, Matlab software is adopted to build a system model for simulation experiment, mechanical vibration generated by external random wind speed to a hydraulic system is added into the system, a vibration waveform like a figure is added, and the simulation effect of PI controller and H infinity robust control is compared with the simulation effect of PI controller and H infinity robust control. When no controller is added according to fig. 5, under disturbance, the system tracking pitch angle speed is slow, the dynamic performance becomes poor, when the hydraulic pitch system with H ∞ robust control is added, the system can keep stable operation after 0.6s, the robust stability and anti-interference performance of the system can be maintained quickly, and the PI control system needs to maintain the stability after 1s and has 2% overshoot. This gives: the H infinity robust controller can make the system less influenced by disturbance, and can quickly eliminate the adverse effect of the disturbance on the system output.
Fig. 9 is a pitch angle bode comparison diagram of the PI control and the H ∞ control. Under the condition that the model parameters are accurate and no external interference exists, the method compares the traditional PI control with the H infinity robust control. As can be seen from fig. 9, the low-frequency gain of the H ∞ robust control is significantly larger than that of the PI adjustment, and the cutoff frequencies of the H ∞ robust control and the PI adjustment are ω respectivelyc1＝7.62rad/s、ωc212.86rad/s, phase angle margin is gamma respectively1＝74.9°、γ287.2. It is readily seen that both the cut-off frequency and the phase angle margin for the H ∞ robust control are larger than PI regulation. From this, it is concluded that: the H infinity stick controller can quickly track the hydraulic variable pitch system relative to PI regulation, and a control object is guaranteed to have certain dynamic performance. Therefore, the H-infinity robust control variable pitch system is better than PI regulation in quick tracking performance, precision and stable robust performance under the conditions of accurate model parameters and no external interference.
The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.

Claims (5)

1. An H infinity robust control method of a hydraulic variable pitch system of a wind turbine generator is characterized by comprising the following steps:
step 1, solving a transfer function of the hydraulic variable pitch system according to a model of the hydraulic variable pitch system, wherein the model comprises a flow equation of an electro-hydraulic proportional reversing valve, a flow continuity equation of a hydraulic cylinder, a stress equation of the hydraulic cylinder and a stress balance equation of an electro-hydraulic proportional pilot valve; the specific process is as follows:
step 1.1, the flow equation of the electro-hydraulic proportional directional valve is as follows:
Qm＝λmxv-λnPm
wherein Q ismM is the flow of the electro-hydraulic proportional reversing valve3/s；λmAs an amplification factor of the flow, m2/s；xvThe displacement is mm of a valve core of the proportional direction valve; lambda [ alpha ]nAs a flow-pressure amplification factor, m5/N·s；PmIs the load pressure of the proportional valve, N;
step 1.2, the hydraulic cylinder flow continuity equation is as follows:
Figure FDA0003098773720000011
wherein A ismIs the area of the piston of the hydraulic cylinder in cm2；ymIs the displacement of the piston of the hydraulic cylinder, mm; t represents time, V0Total volume of hydraulic pressure, m3；βcIs the volume elastic coefficient of the hydraulic cylinder; cmIs the leakage coefficient;
step 1.3, the stress equation of the hydraulic cylinder is as follows:
Figure FDA0003098773720000012
wherein m is a piston and a negativeTotal mass in kg; b isQA viscous damping coefficient for piston and load motion; mu is the force coefficient born by the loaded spring; fQIs the force applied by the load disturbance, N;
step 1.4, the stress balance equation of the electro-hydraulic proportional pilot valve is as follows:
Figure FDA0003098773720000013
wherein i is proportional electromagnet input current, mA; ksfThe spring stiffness, N.m/rad, is detected for the feedback of the electro-hydraulic proportional pilot valve; kiIs a proportional electromagnet force-current amplification factor, N/mA; kbVoltage displacement amplification factor, mA/mm;
step 1.5, the transfer function of the hydraulic pitch control system obtained from steps 1.1-1.4 is:
Figure FDA0003098773720000021
wherein G is0(s) represents a transfer function of the hydraulic pitch system; ktThe electro-hydraulic proportional amplification factor; kmIs a feedback control coefficient, mA/mm; s is a parameter of the transfer function;
step 2, applying the H-infinity robust control to the hydraulic variable pitch system to obtain three closed loop transfer functions of input to tracking error, input voltage and actual output of the hydraulic variable pitch system after the H-infinity robust control;
step 3, selecting a weighting function, converting the H infinity robust control problem into a mixed sensitivity optimization problem, and solving a generalized controlled object of the hydraulic variable pitch system under the mixed sensitivity optimization problem according to the three closed-loop transfer functions in the step 2;
and 4, deducing a state space equation of the generalized controlled object of the hydraulic pitch system according to the generalized controlled object and the weighting function in the step 3, and solving the H-infinity controller K(s) by a hinf function in the Matlab robust control tool box.
2. The H ∞ robust control method of a wind turbine hydraulic pitch system according to claim 1, wherein the closed loop transfer function of step 2 satisfies:
Figure FDA0003098773720000022
wherein S is a sensitivity function; r, T is a complementary sensitivity function; i is a unit transfer function; k(s) is a hydraulic variable pitch system controller; g(s) is a generalized controlled object of the hydraulic variable pitch system; s is a parameter of the transfer function.
3. The H ∞ robust control method of a wind turbine hydraulic pitch system according to claim 1, wherein the weighting function of step 3 is:
W1＝180/(25s+1),W2＝0.008,W3＝(10s+32)/320
wherein, W1Is a weighted function of the sensitivity function S; w2Is a weighted function of the complementary sensitivity function R; w3Is a weighted function of the complementary sensitivity function T; s is a parameter of the transfer function.
4. The H ∞ robust control method of the wind turbine hydraulic pitch system according to claim 1, wherein the generalized controlled object of the hydraulic pitch system under the hybrid sensitivity optimization problem in step 3 is:
Figure FDA0003098773720000031
wherein z is1An evaluation signal for externally inputting r to a tracking error e; z is a radical of2An evaluation signal for an external input r to a system input u; z is a radical of3An evaluation signal for external input r to actual output y; w1Is a weighted function of the sensitivity function S; w2Is a weighted function of the complementary sensitivity function R;W3is a weighted function of the complementary sensitivity function T; i is a unit transfer function; g(s) is a generalized controlled object of the hydraulic variable pitch system; s is a parameter of the transfer function; d is external disturbance; pnIs a generalized controlled-pair matrix of a hydraulic pitch system.
5. The H ∞ robust control method of wind turbine hydraulic pitch system according to claim 1, wherein the state space equation of the generalized controlled object of the hydraulic pitch system in step 4 is:
Figure FDA0003098773720000032
wherein the content of the first and second substances,
Figure FDA0003098773720000033
[x0,x1,x2,x3]-Tis a state variable of the hydraulic variable pitch system; z is a radical of1An evaluation signal for externally inputting r to a tracking error e; z is a radical of2An evaluation signal for an external input r to a system input u; z is a radical of3An evaluation signal for external input r to actual output y; w1Is a weighted function of the sensitivity function S; w2Is a weighted function of the complementary sensitivity function R; w3Is a weighted function of the complementary sensitivity function T;
Figure FDA0003098773720000034
final output for the control object; ktThe electro-hydraulic proportional amplification factor; kmIs a feedback control coefficient, mA/mm; i is a unit transfer function; d is external disturbance; a. then1、Bn1、Cn1、Dn1Is W1Of (A) ann2、Bn2、Cn2、Dn2Is W2Of (A) ann3、Bn3、Cn3、Dn3Is W3Of (2) is used.
CN201910410510.9A 2019-05-17 2019-05-17 H-infinity robust control method for hydraulic variable pitch system of wind turbine generator Active CN110134015B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910410510.9A CN110134015B (en) 2019-05-17 2019-05-17 H-infinity robust control method for hydraulic variable pitch system of wind turbine generator

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910410510.9A CN110134015B (en) 2019-05-17 2019-05-17 H-infinity robust control method for hydraulic variable pitch system of wind turbine generator

Publications (2)

Publication Number Publication Date
CN110134015A CN110134015A (en) 2019-08-16
CN110134015B true CN110134015B (en) 2021-07-20

Family

ID=67574808

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910410510.9A Active CN110134015B (en) 2019-05-17 2019-05-17 H-infinity robust control method for hydraulic variable pitch system of wind turbine generator

Country Status (1)

Country Link
CN (1) CN110134015B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113027677B (en) * 2019-12-25 2023-02-28 新疆金风科技股份有限公司 Hydraulic variable pitch control method and device of wind generating set
US11421653B2 (en) 2020-11-13 2022-08-23 General Electric Renovables Espana, S.L. Systems and methods for multivariable control of a power generating system
CN113031435B (en) * 2021-02-03 2022-07-12 北京航空航天大学 Digital double-frequency extended state observer and disturbance observation method

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101240775A (en) * 2008-03-14 2008-08-13 东南大学 Wind Turbine hydraulic variable pitch system control method
EP2527643A2 (en) * 2011-05-24 2012-11-28 Gamesa Innovation & Technology, S.L. Wind turbine control methods and systems for cold climate and low altitude conditions
CN103362738A (en) * 2012-04-11 2013-10-23 北京能高自动化技术股份有限公司 Maximum power tracking control method of variable speed and variable pitch wind generating set based on feedforward decoupling control
CN104330970A (en) * 2014-05-30 2015-02-04 国家电网公司 Wind turbine pitch variation execution mechanism robust control method based on H-infinity mixed sensitivity
CN105179166A (en) * 2015-06-26 2015-12-23 同济大学 Sampling frequency selection method of wind turbine hydraulic pitch change system
CN107269466A (en) * 2017-07-03 2017-10-20 西安理工大学 A kind of hydraulicdriven wind energy conversion system of feather and its control method
CN109450310A (en) * 2018-11-30 2019-03-08 河海大学 A kind of wind power generating set H of disturbance suppression∞Robust control method

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6171055B1 (en) * 1998-04-03 2001-01-09 Aurora Flight Sciences Corporation Single lever power controller for manned and unmanned aircraft

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101240775A (en) * 2008-03-14 2008-08-13 东南大学 Wind Turbine hydraulic variable pitch system control method
EP2527643A2 (en) * 2011-05-24 2012-11-28 Gamesa Innovation & Technology, S.L. Wind turbine control methods and systems for cold climate and low altitude conditions
CN103362738A (en) * 2012-04-11 2013-10-23 北京能高自动化技术股份有限公司 Maximum power tracking control method of variable speed and variable pitch wind generating set based on feedforward decoupling control
CN104330970A (en) * 2014-05-30 2015-02-04 国家电网公司 Wind turbine pitch variation execution mechanism robust control method based on H-infinity mixed sensitivity
CN105179166A (en) * 2015-06-26 2015-12-23 同济大学 Sampling frequency selection method of wind turbine hydraulic pitch change system
CN107269466A (en) * 2017-07-03 2017-10-20 西安理工大学 A kind of hydraulicdriven wind energy conversion system of feather and its control method
CN109450310A (en) * 2018-11-30 2019-03-08 河海大学 A kind of wind power generating set H of disturbance suppression∞Robust control method

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
《大型风机变桨距控制系统的研究》;窦真兰等;《新能源与风力发电》;20110331;第38卷(第3期);第38-44页 *
《液压变桨型风力机的建模与仿真分析》;高桃桃等;《液压与气动》;20121231(第12期);第53-57页 *
《混合灵敏度问题的鲁棒H∞ /LRT 设计方法》;翁正新等;《控制理论与应用》;19950630;第21卷(第3期);第284-289页 *
《风力发电机液压变桨距系统研究》;任育杰等;《机床与液压》;20121231;第40卷(第23期);第58-60页 *
《风力发电机组液压变桨距控制系统建模及研究》;贾瀚方等;《机床与液压》;20110131;第39卷(第2期);第85-86，89页 *

Also Published As

Publication number Publication date
CN110134015A (en) 2019-08-16

Similar Documents

Publication Publication Date Title
CN110134015B (en) H-infinity robust control method for hydraulic variable pitch system of wind turbine generator
AU2004316333B2 (en) Wind turbine generator, active damping method thereof, and windmill tower
Jonkman Influence of control on the pitch damping of a floating wind turbine
CN109185054B (en) Method, system and device for controlling pitch angle of wind driven generator and readable storage medium
US8258643B2 (en) Method and system for control of wind turbines
EP1907695B8 (en) Wind flow estimation and tracking using tower dynamics
Bagherieh et al. Gain-scheduling control of a floating offshore wind turbine above rated wind speed
US20090295159A1 (en) Adaptive Pitch Control for Variable Speed Wind Turbines
CN102588211A (en) Model prediction control method and model prediction control system for all working conditions of wind generating set
Friis et al. Repetitive model predictive approach to individual pitch control of wind turbines
KR101939903B1 (en) Model Predictive Control With Finite Control Set For Variable-speed Wind Turbines
EP3436693A1 (en) Control of a wind turbine using real-time gain calculation
Girsang et al. Collective pitch control of wind turbines using stochastic disturbance accommodating control
CN111712631B (en) Tower damping in wind turbine power production
EP3436694A1 (en) Control of a wind turbine using real-time blade model
Laks et al. Combined feed-forward/feedback control of wind turbines to reduce blade flap bending moments
Dang et al. Model predictive control for maximum power capture of variable speed wind turbines
Schlipf et al. Multi-variable feedforward control for floating wind turbines using lidar
EP4073375A1 (en) Blade pitch controller for a wind turbine
CN107959453A (en) A kind of improved MRAS speed observation procedure
Wang et al. Research on H∞ Robust Control Strategy of Wind Turbine Hydraulic Variable Pitch System
Tofighi et al. Nonlinear model predictive control approach for structural load mitigation of wind turbines in presence of wind measurement uncertainties
Schlipf Prospects of multivariable feedforward control of wind turbines using lidar
Pham et al. Modified model-free adaptive control method applied to vibration control of an elastic crane
CN112901414A (en) Method for identifying variable pitch system of wind generating set

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant