CN102928612A - Method and system for measuring and calculating rotation speed of rotor of wind driven generator - Google Patents

Abstract

The invention discloses a method for measuring and calculating the rotation speed of a rotor of a wind driven generator. The method comprises the following steps of: sampling current signals on a variable propeller motor at a certain sampling frequency; acquiring spectrum distribution of the current signals; determining a peak value of the spectrum distribution; and calculating the rotation speed of the rotor according to the peak value. A machine-readable recording medium and a computer program are used for implementing the method. The invention also discloses a system for measuring and calculating the rotation speed of the rotor of the wind driven generator. The system comprises a sampling module, a spectrum module, an analyzing module and a calculating module. By the method and the system for measuring and calculating the rotation speed of the rotor of the wind driven generator, additional sensors or other hardware is not required to be mounted, so that the cost is saved, and the structure of the wind driven generator is simplified.

Description

A kind of method and system of calculating the wind power generator rotor rotating speed

Technical field

The present invention relates to a kind of method of calculating the wind power generator rotor rotating speed, particularly relate to the method that a kind of measuring and calculating has the wind power generator rotor rotating speed that becomes the oar motor.In addition, the invention still further relates to carry out this method a kind of machine-readable recording medium and a kind of computer program, and the system that adopts the measuring and calculating wind power generator rotor rotating speed of this method.

Background technology

Every typhoon power generator all has at least one fan blade, and be generally the aerogenerator 1 with three fan blades 12 (only being that a fan blade has marked reference symbol among the figure) that Fig. 1 shows, wherein every fan blade 12 has all independently that the electric power pitch-controlled system rotates with control blade 12.No matter be the aerogenerator of which kind of type, the rotating speed of its rotor must be controlled within the specific limits, otherwise will cause serious consequence to affect safety.A kind of settling mode that prevents over speed of rotation is, after the rotating speed of rotor exceeded allowed band, the position angle of adjusting blade 12 by the electric power pitch-controlled system reduced the capture efficiency of 12 pairs of wind energies of blade.Another kind of settling mode is that the rotating speed on 11 pairs of armature spindles of the central controller of aerogenerator 1 and the generator shaft compares.If these numerical value are inconsistent, for example the rotating speed of the generator shaft rotating speed that surpasses armature spindle multiply by the ratio of gear of rotor tooth roller box, and then aerogenerator will be stopped by force.No matter be to realize above-mentioned which kind of settling mode, its prerequisite all is to adopt first certain means to measure rotating speed.The fault that may occur in order to tackle measuring system also needs to provide at least two independently measured values for the central controller 11 of aerogenerator 1 usually.

US20090193894A1 discloses a kind of scheme of measuring the wind power generator rotor rotating speed, and it comes the rotating speed of rotor is measured by the rotation speed detection unit that is installed on the armature spindle.Except installing the rotation speed detection unit that is consisted of by hardware, also carried out Redundancy Design for the reliability that guarantees signal, namely at each check point two sensors are set, and are provided with respectively corresponding passage in order to transmit detection signal.

WO2007104585A1 discloses the scheme of another kind of measurement wind power generator rotor rotating speed, and it measures centrifugal force by the motion accelerometer that is installed in rotor hub central authorities, and then calculates the rotating speed of rotor.

Although it is effective to adopt above-mentioned two schemes to measure rotor speed, this two schemes all needs extra device (for example, sensor or accelerometer) to realize.This will increase manufacturing and the maintenance cost of aerogenerator undoubtedly.

Summary of the invention

The purpose of this invention is to provide a kind of method that extra sensor or other hardware just can be calculated the wind power generator rotor rotating speed that need not to install, comprising: step S1: with certain sample frequency the current signal that becomes on the oar motor is sampled; Step S2: the spectrum distribution of obtaining described current signal; Step S3: the peak value of determining described spectrum distribution; Step S4: calculate rotor speed according to described peak value.

According to another aspect of the present invention, before described step S2, also comprise step S11: described current signal is stored.This is conducive to obtain the spectrum distribution of long current signal.

According to again one side of the present invention, in described step S2, the spectrum distribution of obtaining described current signal is by carrying out Fast Fourier Transform (FFT) or realizing by the method for estimating the time domain cycle.

According to another aspect of the present invention, after described step S4, also comprise step S5: described rotor speed is proofreaied and correct.This is conducive to reduce the impact that the reason because of certain typhoon power generator self causes rotor speed.

According to one aspect of the present invention, after described step S4, also comprise step S6: to become by each of a typhoon power generator oar motor calculate described rotor speed average.This is conducive to reduce the impact that rotor speed caused by certain reason of sampling self.

The present invention also aims to provide a kind of adopt this method need not to install the system that extra sensor or other hardware just can be calculated the wind power generator rotor rotating speed, for the aerogenerator with at least one rotor, fan blade, a change oar motor and a change oar controller, wherein said change oar controller is rotatably installed in described epitrochanterian described blade by controlling described change oar motor; Described system comprises: sampling module is used for certain sample frequency the current signal on the described change oar motor being sampled; The frequency spectrum module is for the spectrum distribution of obtaining described current signal; Analysis module is for the peak value of determining described spectrum distribution; Computing module is used for calculating described rotor speed according to described peak value.

According to another aspect of the present invention, described system also comprises, memory module is used for described current signal is stored.This is conducive to obtain the spectrum distribution of long current signal.

According to again one side of the present invention, described system also comprises, correction module is used for described rotor speed is proofreaied and correct.This is conducive to reduce the impact that the reason because of certain typhoon power generator self causes rotor speed.

According to another aspect of the present invention, described frequency spectrum module is by carrying out Fast Fourier Transform (FFT) or obtaining the spectrum distribution of described current signal by the method for estimating the time domain cycle.

The present invention also aims to provide a kind of machine-readable recording medium, it records the instruction of the said method of being carried out by a machine.

The present invention also aims to provide a kind of computer program, it comprises code, and when described computer program ran in the machine, described code was so that described machine is carried out said method.

The invention has the advantages that: the rotor speed of calculating aerogenerator by the current value on the measured change oar motor of electric power change oar controller, compared with prior art the present invention need not to install extra sensor or other hardware, thereby provided cost savings, simplified the structure of aerogenerator, also improved simultaneously reliability.

Description of drawings

In conjunction with the following drawings, it is clearer that the features and advantages of the present invention will become, wherein identical parts or the device of identical symbolic representation:

Fig. 1 has schematically showed aerogenerator 1, wherein has azimuth angle theta between the tower cylinder of a fan blade 12 and aerogenerator 1;

Fig. 2 has schematically showed the electric power variable blade control system that is used for a fan blade 12;

Fig. 3 has schematically showed the process flow diagram of the method for measuring and calculating wind power generator rotor rotating speed of the present invention;

Fig. 4 has schematically showed the system 2 of measuring and calculating wind power generator rotor rotating speed, and this system 2 adopts the method for measuring and calculating wind power generator rotor rotating speed shown in Figure 3;

Fig. 5 has shown simulated inverse torque T in 0 to the 10th second process _BRThe result of the Fast Fourier Transform (FFT) of gained;

Fig. 6 has shown a series of to reactive torque T _BRAnalog result, wherein the solid line among Fig. 6 (A) is torque T _M, dotted line is friction torque T _f, and dot-and-dash line is active torque T _KSolid line is the rotating speed of change oar motor 15 among Fig. 6 (B), and dotted line is the pitch angle; Solid line among Fig. 6 (C) is wind speed;

Fig. 7 has schematically showed the electric power pitch-controlled system that meets IEC 61400-13 standard, wherein the z axle vertically stretches to the tip of blade 12 along blade 12, and the y axle is parallel to the nonangular line of the root of blade 12, the x axle is perpendicular to y axle and z axle and the back edge of stretching to blade 12, so that x, y, z meet the right-hand rule;

Fig. 8 has showed that schematically rotor is with rotating speed W _rAct on the power on the blade 12 during rotation;

Fig. 9 has schematically showed by what aerodynamic force caused and has acted on bending moment on the blade 12;

Figure 10 has schematically showed the gravity that acts on the blade 12;

Figure 11 has schematically showed the centrifugal force that acts on the blade 12.

List of numerals:

1 aerogenerator; 11 aerogenerator central controllers

12 blades, 13 pitch variable bearings;

14 variable propeller gearboxes; 15 become the oar motor;

16 become the oar controller; 17 rotary encoders;

The system of 2 measuring and calculating wind power generator rotor rotating speeds; 21 sampling modules;

211 memory modules; 22 frequency spectrum modules;

23 analysis modules; 24 computing modules;

25 correction modules; The θ position angle;

W _rRotor speed; T _BRReactive torque;

The β ratio of gear.

Embodiment

Fig. 2 has shown the electric power pitch-controlled system that is used for a fan blade 12, and this system comprises blade 12, pitch variable bearings 13, variable propeller gearbox 14, becomes oar motor 15, becomes oar controller 16 and rotary encoder 17, and wherein blade 12 is fixed to the inner ring of pitch variable bearings 13.The inner ring of pitch variable bearings 13 is an annular wheel, and the gear on the variable propeller gearbox 14 and the engagement of this annular wheel.Therefore, when becoming oar motor 15 driving variable propeller gearbox 14, blade 12 will correspondingly rotate.Become oar motor 15 and can be polytype, such as direct current generator, asynchronous AC motor, synchronous servo motor etc.Change oar controller 16 as motion controller is used for becoming the angle position that oar motor 15 changes blade 12 by control, and position and the speed of blade 12 and change oar motor 15 are measured constantly by for example position-measurement device of rotary encoder 17 or proximity transducer.

In the aerogenerator operational process, for blade 12 is remained on certain position, becoming oar motor 15 needs to produce the moment of torsion that adapts with certain wind speed.When wind speed becomes large, become 16 controls of oar controller and become oar motor 15 and blade 12 is turned to certain position meet the specified speed of aerogenerator central controller 11 with the rotor speed that guarantees aerogenerator 1.Become moment of torsion that oar motor 15 produces by the mechanical drive train amplification that formed by pitch variable bearings 13 and variable propeller gearbox 14 and be delivered to blade 12.

According to one embodiment of the present invention, Fig. 3 has showed according to the electric current that becomes on the oar motor 15 and has calculated rotor speed W _rThe process flow diagram of method.This method may further comprise the steps successively,

Step S1: the current signal signal that becomes on the oar motor 15 is sampled with certain sample frequency;

Step S11: current signal is stored;

Step S2: the spectrum distribution of obtaining current signal, for example obtain the numerical curve according to frequency, wherein both can obtain spectrum distribution by sampled signal is carried out Fast Fourier Transform (FFT), the method in time domain cycle that also can be by estimating sampled signal replaces Fast Fourier Transform (FFT) to obtain spectrum distribution;

Step S3: determine the peak value of spectrum distribution, for example find peak and corresponding frequency thereof on the numerical curve;

Step S4: calculate rotor speed according to peak value;

Step S5: rotor speed is proofreaied and correct;

Step S6: to become by each of aerogenerator 1 oar motor 15 calculate rotor speed average.

It is pointed out that step S11 is not necessary, the current signal that also step S1 sampling can be obtained is directly delivered to step S2 obtaining the spectrum distribution of current signal, but step S11 is conducive to obtain the spectrum distribution of long current signal.In addition, step S5 and step S6 neither be necessary, and wherein step S5 is conducive to reduce the impact that the reason because of certain typhoon power generator self causes rotor speed, and step S6 is conducive to reduce the impact that rotor speed caused by certain reason of sampling self.When rotor speed is carried out timing, the default value of correction coefficient k is 1.0, and can adjust in the trial run stage of aerogenerator 1, to calculate more accurately rotor speed.When to become by each of aerogenerator 1 oar motor 15 calculate rotor speed when averaging, for aerogenerator 1 blade quantity N=3, the blade that concerning other aerogenerator, also can have other quantity.

According to another embodiment of the present invention, the system 2 of the measuring and calculating wind power generator rotor rotating speed of showing by Fig. 4 realizes said method.Originally just had and measured the sensors that become the electric current on the oar motor 15 owing to become oar controller 16, thus system 2 can realize on the basis of aerogenerator 1 fully, and need not to install extra sensor or other hardware.System 2 comprises: sampling module 21, be used for performing step S1, and namely with certain sample frequency the current signal on the described change oar motor 15 is sampled; Memory module 211 is used for performing step S11, namely described current signal is stored; Frequency spectrum module 22, be used for performing step S2, namely obtain the spectrum distribution of described current signal, its intermediate frequency spectrum module can be obtained by carrying out Fast Fourier Transform (FFT) the spectrum distribution of described current signal, perhaps obtains the spectrum distribution of described current signal by the method for estimating the time domain cycle; Analysis module 23 is used for performing step S3, namely determines the peak value of described spectrum distribution; Computing module 24 is used for performing step S4, namely calculates described rotor speed according to described peak value; Correction module 25 is used for performing step S5, namely described rotor speed is proofreaied and correct.It is to be noted, memory module 211 and correction module 25 are not necessary, the current signal that also sampling module 21 samplings can be obtained is directly delivered to frequency spectrum module 22 to obtain the spectrum distribution of current signal, and determine according to actual conditions whether needs are proofreaied and correct rotor frequency, but memory module 211 is conducive to obtain the spectrum distribution of long current signal, and correction module 25 is conducive to reduce the impact that the reason because of certain typhoon power generator self causes rotor speed.

Fig. 5 has shown simulated inverse torque T in 0 to the 10th second process _BRThe result of the Fast Fourier Transform (FFT) of gained when wherein peak value appears at frequency and is 0.33Hz, and can draw rotor speed W according to above-mentioned steps S4 _rBe 0.33Hz * 60=19.8rpm.In view of the actual average rotor speed at 0 to the 10th second is 19.4rpm, so the error rate of this rotor speed measuring and calculating is about 2%.

The below describes the principle of technique scheme.

When becoming oar motor 15 rotation blade 12, become the torque T that oar motor 15 produces _MAmplified rear drive pitch variable bearings 13 and blade 12 with angular acceleration by variable propeller gearbox 14 with ratio of gear β

Motion.In this process, torque T _MNeed the reactive torque T of negative function on pitch variable bearings 13 _BR, wherein I is moment of inertia, and is as follows with equation expression:

$\mathrm{\α}\·T_M=T_{\mathrm{BR}}-I\·\stackrel{\·}{w}$

$T_M=(T_{\mathrm{BR}}-I\·\stackrel{\·}{w})/\mathrm{\α},\left[E1\right]$

θ=wt, wherein w is angular velocity rad/s (radian per second), t is the time

When blade 12 keeps static or uniform rotation, angular acceleration

Be zero, the torque T after namely amplifying with ratio of gear β _MEqual reactive torque T _BRReactive torque T _BRComprise friction torque T _fWith active torque T _K, the two all produces at blade 12 because of the acting in conjunction of aerodynamic force, gravity and centrifugal force.When blade 12 turned to different positions, these masterpieces were used in the friction torque T that causes on the blade 12 _fWith active torque T _KDifference, i.e. friction torque T _fWith active torque T _KBe the function (referring to formula E16 and E18 after this) of cos θ, wherein θ is the position angle of blade 12 among Fig. 1.Therefore can calculate the period/frequency of rotor by analyzing its these power, and then calculate rotor speed.

T _BR＝T _f+T _K

$T_M={\mathrm{\&lambda;}}_2\&CenterDot;\cos \mathrm{\&theta;}+{[{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000081833070000031.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\&CenterDot;\ln (H+R\cos (\mathrm{\&theta;}+\mathrm{\&pi;}))+k_3]}^2+{\mathrm{\&mu;}}_1\sqrt{{\mathrm{\&epsiv;}}_1\&CenterDot;\cos \left(2\mathrm{\&theta;}\right)+{\mathrm{\&epsiv;}}_2}+{\mathrm{<figure-callout\; id="5"\; label="k"\; filenames="HDA0000081833070000021.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">k</figure-callout>}}_5,\left[E2\right]$

Wherein, k ₂, k ₃, H, R be the amount (referring to formula E6) irrelevant with θ; μ ₁Be friction factor (referring to formula E15); λ ₂, ε ₁, ε ₂For with the irrelevant amount (referring to formula E16) of θ; k ₅For with the irrelevant amount (referring to formula E19) of θ.

Consider the torque T that becomes oar motor 15 _MThe T that concerns with electric current on it _M=C _mI φ, wherein C _mBe the moment of torsion time constant, i is for becoming the electric current on the oar motor 15, and φ is magnetic field intensity, so current i and T _MLinear, comprise identical cos θ composition; Because the cycle of cos θ is

Consistent with the swing circle of rotor, therefore can calculate rotor speed w, i.e. W according to the frequency curve (for example: obtain by fast fourier transform) of current i _r

Fig. 6 has shown a series of to reactive torque T _BRAnalog result, friction torque T wherein _fWith active torque T _KContinuous action is 20 seconds on the pitch variable bearings 13 of the aerogenerator 1 of 1.5MW.The result shows, becomes the torque T of oar motor 15 _MWith reactive torque T _BRAll there is obviously identical sine-wave oscillation, just torque T _MThe amplitude of vibration is less.Wherein, when wind speed was increased to 16m/s from 12m/s, the pitch angle of blade 12 still remained on 12.5 ° consistently until the 15th second, and blade 12 is become oar motor 15 and turns to 20 ° subsequently, and this moment, rotor speed was increased to 25rpm from 20rpm.Solid line among Fig. 6 (A) is torque T _M, dotted line is friction torque T _f, and dot-and-dash line is active torque T _KSolid line is the rotating speed of change oar motor 15 among Fig. 6 (B), and dotted line is the pitch angle; Solid line among Fig. 6 (C) is wind speed.

The below is to the reactive torque T on the pitch variable bearings 13 _BRThe function that why is cos θ describes.For the convenience of discussing, here take the electric power pitch-controlled system that meets IEC 61400-13 standard shown in Figure 7 as example, wherein the z axle vertically stretches to the tip of blade 12 along blade 12, and the y axle is parallel to the nonangular line of the root of blade 12, the x axle is perpendicular to y axle and z axle and the back edge of stretching to blade 12, so that x, y, z meet the right-hand rule.

In the process that blade 12 rotates, there are three class masterpieces to be used on the blade 12, i.e. aerodynamic force, gravity and centrifugal force.

(1) acts on aerodynamic force on the blade 12

When flowing through aerofoil profile, air can produce aerodynamic force F _a, it is along the component q of x axle _XaWith the component q along the y axle _YaAs follows:

$q_{\mathrm{xa}}=\frac{F_{\mathrm{xa}}}{\mathrm{dr}}=\frac{1}{2}\mathrm{\&rho;}{\mathrm{SV}}^{\&prime;2}{C}_n=\frac{1}{2}{\mathrm{\&rho;SV}}^{\&prime;2}(C_l\cos \mathrm{\&psi;}+C_d\sin \mathrm{\&psi;})$

$q_{\mathrm{ya}}=\frac{F_{\mathrm{ya}}}{\mathrm{dr}}=\frac{1}{2}\mathrm{\&rho;}{\mathrm{SV}}^{\&prime;2}{C}_t=\frac{1}{2}\mathrm{\&rho;}{\mathrm{SV}}^{\&prime;2}(C_l\sin \mathrm{\&psi;}-C_d\cos \mathrm{\&psi;})$

Wherein ψ is angle of attack α and pitch angle γ sum, i.e. ψ=α+γ, and ρ is atmospheric density, and V ' is the relative velocity of air-flow, and S is chord length, C _lAnd C _dBe respectively lift coefficient and drag coefficient.

Because aerodynamic force causes bending moment M to blade 12 roots at x axle and y axle _XaAnd M _YaAs follows:

$M_{\mathrm{xa}}={\&Integral;}_r^R(r_1-r)q_{\mathrm{ya}}{\mathrm{<figure-callout\; id="1"\; label="dr"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">dr</figure-callout>}}_1,\left[E3\right]$

$M_{\mathrm{ya}}={\&Integral;}_r^R(r_1-r){\mathrm{<figure-callout\; id="1"\; label="q\; xa\; dr"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">q</figure-callout>}}_{\mathrm{xa}}{\mathrm{dr}}_{}{}_1,\left[E4\right]$

Wherein Fig. 9 has showed by what aerodynamic force caused and has acted on bending moment M on the blade 12 _XaAnd M _Ya, and variable r and r ₁The active moment that is caused by aerodynamic force is as follows:

$d_{\mathrm{pc}}=\sqrt{{(x_p-x_C)}^2+{(y_p-y_C)}^2}$

Wherein, the coordinate of the Center of Pressure of blade 12 is (x _p, y _p), the coordinate of the rotation center of blade 12 is (x _C, y _C), because wind speed can be with height change, according to the IEC61400-1 standard, the wind speed V ' at height h place (h) can be expressed as:

Wherein, V _HBe the known wind speed at reference altitude H place, for example the wind speed at hub height place can be thought constant at short notice; h ₀The surface roughness constant,

With

Be the amount irrelevant with θ.

When rotor diameter is R, have h=H-Rcos (θ)=H+Rcos (θ+π),

So V ' (h)=k ₂Ln (H+Rcos (θ+π))+k ₃, [E6]

Therefore, wind speed V ' is the function of cos θ (h).According to formula [E3]～[E6], M _Xa, M _YaAnd T _KaAll are V ' ²Multiple; Again because function f (x)=ln ²(x) monotone increasing in [H-R, H+R] is interval, so M _Xa, M _YaAnd T _KaThe cycle that all comprises cos θ

The fluctuation composition.

(2) act on gravity on the blade 12

As shown in figure 10, when Action of Gravity Field is on blade 12 its along the component q of y axle _YwWith the component q along the z axle _ZwAs follows:

$\left\{\begin{array}{c}{q}_{\mathrm{yw}}=-{\mathrm{\&rho;}}_0{S}_{0}g\sin \mathrm{\&theta;}\\ q_{\mathrm{zw}}=-{\mathrm{\&rho;}}_0{S}_{0}g\cos \mathrm{\&theta;}\end{array}\right.$

Wherein, ρ ₀Be the density of blade 12, S ₀Be the sectional area of the sheet material of making blade 12, g is acceleration of gravity.

The bending moment M that causes because of gravity _XWFor:

$M_{\mathrm{xw}}=-\left[{\&Integral;}_r^R(r_1-r){\mathrm{\&rho;}}_0\mathrm{<figure-callout\; id="0"\; label="g\; s"\; filenames="HDA0000081833070000032.png,HDA0000081833070000041.png"\; state="\{\{state\}\}">g</figure-callout>}{s}_{}{}_0{\mathrm{dr}}_1\right]\&CenterDot;\sin \mathrm{\&theta;}=-\left[{\&Integral;}_r^R(r_1-r){\mathrm{\&rho;}}_0\mathrm{<figure-callout\; id="0"\; label="g\; S"\; filenames="HDA0000081833070000032.png,HDA0000081833070000041.png"\; state="\{\{state\}\}">g</figure-callout>}{S}_{}{}_0{\mathrm{dr}}_1\right]\&CenterDot;\cos (\mathrm{\&theta;}-\frac{\mathrm{\&pi;}}{2}),\left[E7\right]$

M _yw＝0，[E8]

The active torque T that is caused by gravity _KWIrrelevant with θ, for:

$T_{\mathrm{KW}}={\&Integral;}_r^R{\mathrm{\&rho;}}_{0}g{S}_0(X_G-X_C){\mathrm{<figure-callout\; id="1"\; label="dr"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">dr</figure-callout>}}_1,\left[E9\right]$

Wherein, X _GBe the coordinate of blade 12 centers of gravity, and X _CCoordinate for rotation center.

By what gravity caused along the power to pitch variable bearings 13 on the z axle be:

$F_{\mathrm{zw}}=-\left[{\&Integral;}_r^R{\mathrm{\&rho;}}_0\mathrm{<figure-callout\; id="0"\; label="g\; S"\; filenames="HDA0000081833070000032.png,HDA0000081833070000041.png"\; state="\{\{state\}\}">g</figure-callout>}{S}_{}{}_0{\mathrm{dr}}_1\right]\&CenterDot;\cos \mathrm{\&theta;}={\mathrm{\&lambda;}}_1\&CenterDot;\cos \mathrm{\&theta;}.\left[E10\right]$

Therefore, according to formula [E7]～[E10], M _XwAnd F _ZwBe the linear function of cos θ, and T _KWIrrelevant with θ.

(3) act on centrifugal force on the blade 12

As shown in figure 11, the centrifugal force that acts on the blade 12 is as follows:

$q={\mathrm{\&rho;}}_0{W_r}^2{S}_{0}L={\mathrm{\&rho;}}_0{W_r}^2{S}_0\sqrt{{(r+r_H)}^2+{\mathrm{<figure-callout\; id="2"\; label="Y\; G"\; filenames="HDA0000081833070000031.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">Y</figure-callout>}}_G^{}}$

Wherein, W _rBe the rotor speed of aerogenerator 1, L is the distance between center to the wheel hub center of blade 12, r _HRadius for wheel hub.

The bending moment M that is caused by centrifugal force _XpAnd M _YpAs follows:

$M_{\mathrm{xp}}={\&Integral;}_r^R(r_1-r){\mathrm{\&rho;}}_0{W_r}^2{S}_0{Y}_G\left(r_1\right){\mathrm{<figure-callout\; id="1"\; label="dr"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">dr</figure-callout>}}_1,\left[E11\right]$

$M_{\mathrm{yp}}={\&Integral;}_r^R[Y_G\left(r_1\right)-Y_G\left(r\right)]{\mathrm{\&rho;}}_0{W_r}^2{S}_0({\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+r_H){\mathrm{<figure-callout\; id="1"\; label="dr"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">dr</figure-callout>}}_1,\left[E12\right]$

The active torque that is caused by centrifugal force is:

$T_{\mathrm{KP}}=-{W_r}^2\left\{{\&Integral;}_r^R{\mathrm{\&rho;}}_0{S}_0{X}_G\left(r_1\right)[Y_G\left(r\right)-Y_G\left(r_1\right)]{\mathrm{<figure-callout\; id="1"\; label="dr"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">dr</figure-callout>}}_1+{\&Integral;}_r^R{\mathrm{\&rho;}}_0{S}_0{Y}_G\left(r_1\right)[X_G\left(r\right)-X_G\left(r_1\right)]{\mathrm{dr}}_1\right\},\left[E13\right]$

By what centrifugal force caused along the z axle to the power of pitch variable bearings 13 be:

$F_{\mathrm{zp}}={\&Integral;}_r^R{\mathrm{\&rho;}}_0{W_r}^2{S}_0({\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">r</figure-callout>}}_1+r_H){\mathrm{<figure-callout\; id="1"\; label="dr"\; filenames="HDA0000081833070000011.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">dr</figure-callout>}}_1,\left[E14\right]$

Therefore, according to formula [E11]～[E14], M _Xp, M _Yp, T _KPAnd F _ZpAll irrelevant with θ.

Because the friction force on the pitch variable bearings 13 is axial force F _Axial, radial force F _RadialAnd bending moment M multiply by corresponding coefficientoffrictionμ, therefore, and friction torque T _fCan following formal representation:

T _f＝μ ₁·M+μ ₂·R _b·F _axial+μ ₃·R _b·F _radial，[E15]

μ wherein ₁, μ ₂, μ ₃Friction factor, R _bBe the pitch variable bearings radius, F _Axial=F _z, F _Radial≈ 0 (the radial force F on the pitch variable bearings 13 _RadialClose to zero)

M _x＝M _xa+M _xw+M _xp，M _y＝M _ya+M _yw

So, Exponential function

Monotone increasing in codomain, so M comprises cos's (2 θ)

Periodic component.

F _Axial=F _z=F _Zw+ F _ZpIn F _ZwThe linear function (referring to formula E10) of cos θ, the cycle F _ZpWith θ irrelevant (referring to formula E14).

Therefore, $T_f={\mathrm{\&lambda;}}_2\&CenterDot;\cos \mathrm{\&theta;}+{\mathrm{\&mu;}}_1\&CenterDot;\sqrt{{\mathrm{\&epsiv;}}_1\&CenterDot;\cos \left(2\mathrm{\&theta;}\right)+{\mathrm{\&epsiv;}}_2}+{\mathrm{\&lambda;}}_3,\left[E16\right]$

Wherein, λ ₂=μ ₂R _bλ ₁And λ ₃=μ ₂R _bF _ZpBe the amount irrelevant with θ.

Because the whole active torque that act on the pitch variable bearings 13 can be expressed as:

T _K＝T _z＝T _Ka+T _KW+T _KP，[E17]

So T _K=[k ₂Ln (H+Rcos (θ+π))+k ₃] ²+ k ₄, [E18]

Wherein, k ₄=T _KW+ T _KPFor with the irrelevant amount of θ.

In sum, in view of friction torque T _f(referring to E16) and active torque T _K(referring to E18) is the function of cos θ, so moment of torsion $T_M=T_f+T_K={\mathrm{\&lambda;}}_2\&CenterDot;\cos \mathrm{\&theta;}+{[{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="HDA0000081833070000031.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">k</figure-callout>}}_2\&CenterDot;\ln (H+R\cos (\mathrm{\&theta;}+\mathrm{\&pi;}))+k_3]}^2+{\mathrm{\&mu;}}_1\sqrt{{\mathrm{\&epsiv;}}_1\&CenterDot;\cos \left(2\mathrm{\&theta;}\right)+{\mathrm{\&epsiv;}}_2}+{\mathrm{<figure-callout\; id="5"\; label="k"\; filenames="HDA0000081833070000021.png,HDA0000081833070000032.png"\; state="\{\{state\}\}">k</figure-callout>}}_5,$ [E19] also is the function of cos θ, wherein k ₅=k ₄+ λ ₃Again because T _M=C _mI φ is so the current i on the change oar motor 15 also can be expressed as the function of cos θ.Because the cycle of cos θ is

So can calculate rotor speed ω, i.e. W by the signal of processing current i _rThe present invention need not to install extra sensor or other hardware, thereby has provided cost savings, simplified the structure of aerogenerator.

Although more than showed embodiments of the present invention, described embodiment is not intended to show all possible form of the present invention.In addition, the content in this instructions is descriptive, and nonrestrictive.Those skilled in the art can make variations and modifications to the content of this instructions, and do not depart from the scope of purport of the present invention and claim.

Claims (11)

1. a method of calculating the wind power generator rotor rotating speed comprises,

Step S1: the current signal that becomes on the oar motor (15) is sampled with certain sample frequency;

Step S2: the spectrum distribution of obtaining described current signal;

Step S3: the peak value of determining described spectrum distribution;

Step S4: calculate rotor speed according to described peak value.

2. the method for measuring and calculating wind power generator rotor rotating speed as claimed in claim 1 is characterized in that, before described step S2, also comprise,

Step S11: described current signal is stored.

3. the method for measuring and calculating wind power generator rotor rotating speed as claimed in claim 1 is characterized in that, in described step S2, the spectrum distribution of obtaining described current signal is by carrying out Fast Fourier Transform (FFT) or realizing by the method for estimating the time domain cycle.

4. such as the method for the described measuring and calculating wind power generator rotor of one of claims 1 to 3 rotating speed, it is characterized in that, after described step S4, also comprise,

Step S5: described rotor speed is proofreaied and correct.

5. such as the method for the described measuring and calculating wind power generator rotor of one of claims 1 to 3 rotating speed, it is characterized in that, after described step S4, also comprise,

Step S6: to become by each of a typhoon power generator oar motor calculate described rotor speed average.

6. system of calculating the wind power generator rotor rotating speed, for the aerogenerator (1) with at least one rotor, fan blade (12), a change oar motor (15) and a change oar controller (16), wherein said change oar controller (16) is rotatably installed in described epitrochanterian described blade (12) by the described change oar motor of control (15); Described system comprises:

Sampling module is used for certain sample frequency the current signal on the described change oar motor (15) being sampled;

The frequency spectrum module is for the spectrum distribution of obtaining described current signal;

Analysis module is for the peak value of determining described spectrum distribution;

Computing module is used for calculating described rotor speed according to described peak value.

7. the system of measuring and calculating wind power generator rotor rotating speed as claimed in claim 6 is characterized in that,

Described frequency spectrum module is by carrying out Fast Fourier Transform (FFT) or obtaining the spectrum distribution of described current signal by the method for estimating the time domain cycle.

8. the system of measuring and calculating wind power generator rotor rotating speed as claimed in claim 7 is characterized in that, described system also comprises,

Memory module is used for described current signal is stored.

9. the system of measuring and calculating wind power generator rotor rotating speed as claimed in claim 8 is characterized in that, described system also comprises,

Correction module is used for described rotor speed is proofreaied and correct.

10. machine-readable recording medium, it records the according to claim 1 instruction of arbitrary described method in 5 of being carried out by a machine.

11. a computer program, it comprises code, and when described computer program ran in the machine, described code was so that arbitrary described method in the described machine executive basis claim 1 to 5.

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