CN105893711A - Wind power generator blade and structural design method thereof - Google Patents

Abstract

The invention discloses a wind power generator blade and a structural design method thereof. The structural design method includes A, estimating the wind speed by a Weibull function model and determining the starting wind speed and the rated wind speed according to a distribution curve of the function model; B, setting the tip-speed ratio, the blade number, the wing section and the wind wheel diameter of the blade; C, calculating to obtain the chord length, the installing angle and the wing section of the blade based on a Wilson method. The structural design method obtains supplementary important parameters for blade structural design by analyzing the blades through dynamics theories and studying and designing the blades in critical positions of a wind power generator in details from deriving the wind speed, selecting the blade number and the wing section to wind wheel diameter calculation.

Description

A kind of blade of wind-driven generator and construction design method thereof

Technical field

The present invention relates to technical field of wind power generator, particularly relate to a kind of blade of wind-driven generator and structure thereof Method for designing.

Background technology

Along with energy demand is continuously increased by the mankind, and fossil energy cause environmental pollution, greenhouse effect Should wait the appearance of problem, energy security has become the sixty-four dollar question that countries in the world face.Wind energy is current Having most the renewable and clean energy resource of exploitation prospect, wind-power electricity generation enjoys as the major way of Wind Power Utilization Pay close attention to.China's accumulative installed capacity of wind-driven power in addition to Taiwan has reached 44,000,000 kilowatts, and alreading more than the U.S. becomes dress The wind-powered electricity generation big country of machine first.Domestic wind-power market comes into the high speed development stage, and the market of Wind Power Development is empty Between the hugest.Realize equipment industrialization, reduce the needs that construction costs is wind-powered electricity generation extensive development.

Wherein, blade is the critical component that wind power generating set absorbs wind energy, leaf quality quality direct relation The security of unit operation.The load of unit is mainly produced by blade, and the load that blade bears mainly has suction The centrifugal force load produced when the aerodynamic loading of load of calling prisoners in after letting them out for exercise, gravitational load own and rotation.Along with unit Capacity constantly increases, and the length of blade is more and more longer, and in order to reduce cost, the blade of shell structure also becomes Obtaining more and more lighter and handier, the flexibility of structure becomes the biggest.Blade is cut by atmospheric boundary layer in rotary course Wind cutting, random fitful wind, tower shadow effect, change oar, driftage, pneumatic imbalance, the elastic recovery of blade itself Affecting etc. factor, define the exciting source of complexity, the multifactorial structure Coupling thus caused vibration is more carried out the coffin upon burial Rise and pay attention to.The principal mode of vibration shows as waving, deploying and twisting vibration.

Therefore, for the vibration mechanism for blade, the detection of the vibration characteristics under different wind speed, and accordingly The blade design research carrying out the wind-driven generator carried out is significant.

Summary of the invention

In place of above-mentioned the deficiencies in the prior art, it is an object of the invention to provide a kind of wind-driven generator leaf Sheet and construction design method thereof, it is intended to the problem solving blade construction of the prior art design.

In order to achieve the above object, this invention takes techniques below scheme:

A kind of blade structure for wind driven generator method for designing, wherein, described method for designing includes:

A, use Weibull function model assessment wind speed, and according to the distribution curve of function model, determine startup Wind speed and rated wind speed；

B, the setting tip-speed ratio of blade, the number of blade, aerofoil profile and rotor diameter；

C, based on Wilson's method, calculate and obtain the chord length of foline, established angle and aerofoil profile.

Described blade structure for wind driven generator method for designing, wherein, in described step B, is calculated by following Formula estimation rotor diameter:

P=CP (1/2) ρ P (3 π π D2/* η 1* η 2=0.49V13D2 η 1 η η

Wherein, P is wind driven generator output power, and V1 is the wind speed of design, and D is rotor diameter, and ρ is empty The density of gas, η 1 is the efficiency of generator, and η 2 is transmission efficiency.

A kind of blade of wind-driven generator using method for designing as above, wherein, described wind-driven generator leaf Sheet is NACA4412 aerofoil profile, and the number of blade is 3, and blade is equally divided into 18 cross sections.

Described blade of wind-driven generator, wherein, described blade of wind-driven generator is glass steel material.

Described blade of wind-driven generator, wherein, described blade of wind-driven generator also includes blade monitoring device；

Described blade monitoring device includes: gather the data acquisition unit of blade run signal；With data acquisition list Unit connects, and obtains described blade run signal, and carries out Logic judgment accordingly, output corresponding control signal Processor unit and being connected with described processor unit, obtains described control signal and performs corresponding operating Executing agency.

Described blade of wind-driven generator, wherein, described data acquisition unit includes obtaining blade vibration acceleration The acceleration transducer of signal and the speed probe of acquisition wheel speed signal.

Described blade of wind-driven generator, wherein, between described data acquisition unit and processor unit the most successively It is provided with analog to digital conversion circuit；

After described blade run signal is converted to voltage signal, change through analog to digital conversion circuit, input to described place Reason device unit.

Described blade of wind-driven generator, wherein, described blade monitoring device also includes a filter cell；

Described filter cell is connected with described processor unit, filters the signal that processor unit obtains；Described Processor unit, after filter cell processes, calculates signal frequency mean value and exports the control signal of correspondence.

Described blade of wind-driven generator, wherein, described filter cell rejection frequency at 1.7-1.75Hz and The signal in two stages of 3.05-3.2Hz.

Described blade of wind-driven generator, wherein, described filter cell is active filter circuit.

Beneficial effect: a kind of blade of wind-driven generator of present invention offer and construction design method thereof, uses Blade is analyzed by dynamic (dynamical) theory, from the derivation of wind speed, to the selection of blade quantity, arrives aerofoil profile Choose, then to the calculating to rotor diameter, the detailed key position blade to wind-driven generator is ground Study carefully and design, it is thus achieved that the important parameter in blade construction design, be the good benefit to blade construction design Fill.

Further, it is also provided with blade monitoring system, and is achieved in for the guarantor in blade running Protect, effectively ensured the safety and reliability etc. of unit operation, had a good application prospect.

Accompanying drawing explanation

Fig. 1 is the method flow diagram of the blade of wind-driven generator method for designing of the specific embodiment of the invention.

Fig. 2 is the functional schematic of the blade monitoring system of the specific embodiment of the invention.

Fig. 3 is the sensor placement schematic diagram of the blade monitoring system of the specific embodiment of the invention.

Fig. 4 is the hardware structure diagram of the blade monitoring system of the specific embodiment of the invention.

Fig. 5 is the circuit diagram of the bandpass filter of the blade monitoring system of the specific embodiment of the invention.

Fig. 6 is the input flow chart of the bandwidth-limited circuit of the blade monitoring system of the specific embodiment of the invention.

Fig. 7 is the execution flow chart of the processor unit of the blade monitoring system of the specific embodiment of the invention.

Fig. 8 is signals collecting and the schematic diagram of transmission circuit of the blade monitoring system of the specific embodiment of the invention

Detailed description of the invention

The present invention provides a kind of blade of wind-driven generator and construction design method thereof.For make the purpose of the present invention, Technical scheme and effect are clearer, clear and definite, and the embodiment that develops simultaneously referring to the drawings is the most detailed to the present invention Describe in detail bright.Should be appreciated that specific embodiment described herein, only in order to explain the present invention, is not used to limit Determine the present invention.

As it is shown in figure 1, be the blade structure for wind driven generator method for designing of the specific embodiment of the invention.Described Method for designing includes:

S100, use Weibull function model assessment wind speed, and according to the distribution curve of function model, determine Threshold wind velocity and rated wind speed.

General, in actual life, the change of wind speed is very big, is difficult to by a kind of Mathematical Modeling accurately it Describe out.Function through conventional estimation wind speed has Weibull function distribution and Rayleigh function to be distributed in the world Two kinds.

Wherein, the Weibull function distribution simple and effective simulation wind speed probabilistic model of energy, is preferably to analyze wind The instrument of energy, its expression formula is:

$F\left(v\right)=\frac{K}{C}{\left(\frac{V}{C}\right)}^{K-1}{e}^{-{\left(\frac{v}{c}\right)}^k}---\left(1\right)$

Wherein, K is form parameter, and without guiding principle amount, C is dimensional parameters, and dimension is m/s.And local different, Time is different, and the parameter of K, C is the most different.And for function curve, the little C of K is little, curve is mild, Peak moves to left.And the big C of K is big, then curve is precipitous, and peak moves to right.

As C=1, Weibull function expression formula is:

$F\left(v\right)=k{\left(V\right)}^{k-1}{e}^{-V^k}---\left(2\right)$

When 0 < K, < when 1, Weibull wind speed probability is the subtraction function of X；As K=1, probability distribution is finger Number change；As K=3, close to normal distribution.

As K=2, wind velocity distributing paremeter formula is:

$F\left(v\right)=\frac{2V}{C^2}{e}^{-\frac{V^2}{C^2}},(C>=0V>=0K>=0)---\left(3\right)$

The probability distribution of Rayleigh function is as probability distribution during above K=2.

Threshold wind velocity for wind-driven generator: wind-driven generator is divided into vertically and horizontally two class, and every class wind Power generator has multiple, and every kind has again plurality of specifications.Suitable wind-driven generator chosen by needs, just can obtain Obtain more wind energy.

According to foregoing description, the peak value of Weibull function distribution curve is exactly toggle speed, to formula (1) derivation, Can obtain

$F^{\&prime;}\left(V\right)=\frac{K}{C}.e^{-{\left(\frac{v}{c}\right)}^k}\frac{K-1}{C}{\left(\frac{V}{C}\right)}^{K-2}-\frac{K}{C}{\left(\frac{V}{C}\right)}^{2(K-1)}$

Because of C ≠ 0, K ≠ 0, so there being following formula:

$\frac{K-1}{C}{\left(\frac{V}{C}\right)}^{K-2}-\frac{K}{C}{\left(\frac{V}{C}\right)}^{2(K-1)}=0$

Further, have

$V_S=Cx\sqrt[K]{\frac{K-1}{K}}---\left(4\right)$

Rated wind speed for wind-driven generator: the specified wind speed of domestic wind-driven generator is about 6m/s and arrives 14m/s.The density P=ρ π of known wind energy, is r for an aerofoil profile radius, and efficiency is the wind-driven generator of η, The Weibull function of the power of output is distributed as

$W\left(V\right)=\mathrm{\&rho;}\mathrm{\&pi;}\frac{K}{C}{\left(\frac{V}{C}\right)}^{K-1}{e}^{-{\left(\frac{v}{c}\right)}^k}---\left(5\right)$

The wind speed that W (V) peak value is corresponding is rated wind speed, and at this moment wind-driven generator can obtain the wind energy of maximum Condition is

$V_P=C\&times;\sqrt[K]{\frac{K+2}{K}}---\left(6\right)$

S200, the setting tip-speed ratio of blade, the number of blade, aerofoil profile and rotor diameter.In the design process, Need some important parameters to blade, select according to actual situation, determine.

Generally in the case of without departing from scope, the wind-driven generator run under high tip-speed ratio state has Higher wind wheel efficiency.And wind wheel tip-speed ratio λ₀Equal to wind wheel blade tip linear velocity and the ratio of the wind speed of design:

${\mathrm{\&lambda;}}_0=\frac{wR}{V_n}---\left(7\right)$

The number of blade of wind wheel is then relevant with the purposes of wind-driven generator, compares λ with the sharp number of wind wheel₀Unrelated.Now Wind-driven generator be generally used for generating, it is contemplated that its operation and power output, commonly used three blade wind Power generator.

The aerofoil profile of wind-driven generator is particularly significant to the efficiency of wind-driven generator.The wing of modern wind-driven generator Type is essentially all employing distortion type.Distortion type manufactures relatively difficult, but can improve the utilization effect of wind energy Rate, makes wind-driven generator be obtained in that optimal wind energy utilization efficiency.During designing airfoil, aerofoil profile should be made everywhere Actual installation angle differ, the angle of blade root to blade tip gradually reduce, and make blade locate everywhere In optimal state of angle of attack, thus obtain optimal lift, make blade obtain best wind energy and accept efficiency.

Using NACA4412 aerofoil profile, have noise little, relative thickness is little, and the usage factor of wind energy is high and has There is the feature of good pneumatic property.

Concrete, can be by following formula estimation rotor diameter:

P=CP (1/2) ρ P (3 π π D2/* η 1* η 2=0.49V13D2 η 1 η η (7)

Wherein, P is wind driven generator output power, and V1 is the wind speed of design, and D is rotor diameter, and ρ is empty The density of gas, η 1 is the efficiency of generator, and η 2 is transmission efficiency.

S300, based on Wilson's method, calculate and obtain the chord length of foline, established angle and aerofoil profile.Wilson's sets Meter method (Wilson method for designing) is the method for most common a kind of blade design in the world.Compare Glauer method, Wilson method have studied taper loss and the lift-drag ratio impact on blade optimum performance, and Have studied wind wheel performance under off-design condition.Therefore comparing the former, Wilson method is the most advanced, examines The aspect considered is wider, design the most accurate.

The fundamental formular of Wilson method is as follows:

${\mathrm{dC}}_P=\frac{8}{{{\mathrm{\&lambda;}}^2}_0}b(1-a){\mathrm{F\&lambda;}}^{3}d\mathrm{\&lambda;}---\left(8\right)$

A (1-aF)=b (1+b) λ² (9)

$F=\frac{2}{\mathrm{\&pi;}}arccos\left(e^{-f}\right)---\left(10\right)$

$f=\frac{A}{2}\frac{R-r}{R\sin \mathrm{\&phi;}}---\left(11\right)$

$tan\mathrm{\&phi;}=\frac{V_1(1-a)}{w*r(1+b)}=\frac{1}{\mathrm{\&lambda;}}*\frac{1-a}{1+b}---\left(12\right)$

$\frac{{\mathrm{BCC}}_{L}cos\mathrm{\&phi;}}{8{\mathrm{\&pi;sin}}^2\mathrm{\&phi;}}=\frac{(1-aF)aF}{{(1-a)}^2}---\left(13\right)$

Wherein, CP is the usage factor of wind energy, and usual value is to 0.45.A is the axial interference factor, B is the interference factor of circumference, λ₀For tip-speed ratio, λ is the ratio of the rotating speed at wind wheel radius r and wind speed.

F is Prantl tip loss coefficient, and f is Prantl algorithm intermediate variable；A is the number of blade of wind wheel, R is the radius (m) of f wind wheel；R is the foline cross section distance (m) to wind wheel center；For foline inflow angle (rad)；C is foline chord length (m).

The design procedure of Wilson method specifically includes:

(1) theoretical according to foline, by blade along exhibition to the foline being divided into some parts；

(2) for each foline, with (8) as object function, with (9) optimization as condition Problem, show that the interference coefficient a, b in each cross section and blade tip damage coefficient F；

(3) utilize (12) to calculate and flow wind direction angular motion, determine the torsional angle in each cross section；

(4) (13) are utilized to calculate chord length C；

(5) required blade chord length C and torsional angle are linearly revised, to meet structure and processing side The requirement in face；

(6) consult the aerofoil profile data in handbook, calculate the aerofoil profile coordinate in each cross section.

The parameter designing of wind-driven generator is as follows: wind speed round (r.p.m) 15/22.5；Rated wind speed (m/s) 14.0； Survival wind speed (m/s) 70；Rated power (kw) 750；Length of blade (mm) 2350025；Maximum chord length (mm)225020；Pitch diameter (mm)；Bolt specification M30；Number of Bolts 40；Ring flange external diameter ；Temperature range of operation (C0)-20 to+50.Determining that length of blade is 24m, wind wheel radius is 25m, blade Maximum chord length is 2.35m, put away from blade root be 5.5m.

Result is analyzed with design:

Concrete, wind-power electricity generation airfoil type selects NACA4412 aerofoil profile, and the number of blade is 3, blade 18 cross sections are divided into it in equal size.Computer is used to run interference factor a that can draw arbitrary section, b, r The chord length at place, the tip damages coefficient f, and torsional angle.Concrete outcome is as shown in the table:

In a particular embodiment of the present invention, described blade of wind-driven generator is glass steel material.Glass steel material Blade light weight, intensity good and corrosion-resistant.

The composite of fiberglass is according to different compositely proportionals, and the mechanical attribute of its material is the most different.At this The attribute definition of the bright blade material in specific embodiment is as shown in the table:

It is preferred that described blade of wind-driven generator also includes blade monitoring device.Arranging this monitoring device can Protection blade system so that it is be in safe running status.

As in figure 2 it is shown, described blade monitoring system includes following four major functions: load during operation is supervised Survey, dynamic balancing time monitoring, icing time monitoring, blade injury time monitoring, feedback result is expressed as pre- Warn, shut down, detect, safeguard, regulate, design of feedback etc..

Described crop leaf measuring system mainly includes Fibre Optical Sensor, optical fibre interrogation instrument, data monitoring and biography The parts such as the process of communication system, data, safe prediction.As it is shown on figure 3, sensor can use such as figure Shown layout is arranged.

Described blade monitoring device includes: gather the data acquisition unit 100 of blade run signal；With data acquisition Collection unit connects, and obtains described blade run signal, and carries out Logic judgment accordingly, and output correspondence controls letter Number processor unit 200 and be connected with described processor unit, obtain described control signal and perform phase The executing agency 300 that should operate.

As shown in Figure 4, for the hardware structure diagram of described monitoring device specific embodiment.Wherein, processor unit 200 is single-chip microcomputer, and executing agency 300 is relay, and data acquisition unit 100 includes multiple sensor.

The signal of the acceleration gathered by sensor can be converted to voltage signal through sensor, then passes through It is sent directly into single-chip microcomputer after the conversion of A/D.

Then, described filter cell rejection frequency is at the letter in two stages of 1.7-1.75Hz and 3.05-3.2Hz Number.

Finally, in 5 seconds, obtain signal frequency mean value, when mean value is less than setting value, work on； Otherwise, relay sends the signal of shutdown.

Described data acquisition unit includes acceleration transducer and the acquisition obtaining blade vibration acceleration signal The speed probe of wheel speed signal.

Under normal circumstances, acceleration transducer when measuring high-frequency signal, when measuring intermediate-freuqncy signal, operating speed passes Sensor, and use displacement transducer when measuring low frequency.But, when installing inconvenient, displacement transducer can To replace monitoring low frequency signal with acceleration transducer.Concrete, it is possible to use model is LC0750A's Sensor, it has, and noise is low, anti-interference, low drifting, and anti-overload ability is strong, the advantage that cost performance is high.

More specifically, analog-to-digital conversion also it is disposed with between described data acquisition unit and processor unit (A/D) circuit.After described blade run signal is converted to voltage signal, change through analog to digital conversion circuit, defeated Enter to described processor unit.

Concrete, analog to digital conversion circuit can use MAX187, and this chip is the mould of 12 parallel-by-bits Number converter.As it has been described above, signal delivers to MAX187 through the signal of preposition shaping and filtered voltage In, analog quantity can produce the digital voltage amount of 12 after analog-to-digital conversion, after converting The data of conversion can be read via single-chip microcomputer by the way of interruption.

In a particular embodiment of the present invention, described blade monitoring device also includes a filter cell.Described filter Ripple device unit is connected with described processor unit, filters the signal that processor unit obtains；Described processor list Unit, after filter cell processes, calculates signal frequency mean value and exports the control signal of correspondence.

More specifically, described filter cell can use active filter circuit.By low pass filter 101 and height Bandpass filter 102 is mutually combined, and forms bandwidth-limited circuit (as shown in Figure 5).In actual use, The input flow process of described bandwidth-limited circuit is as shown in Figure 6.First the signal of input is carried out RC network filter Ripple and sampling, then by analog-to-digital conversion, interrupt after completing and read the result converted by subprogram, as The input of digital band-pass filter.As it is shown in fig. 7, be the execution flow chart of described processor unit.

Described crop leaf measuring system also includes a wireless transport module, is used for transmitting instruction and signal etc..Described Wireless transport module can use the nRF24E1 module that NORDIC company produces.This module wireless Transceiver works under the ISM band of 2.4GHz, and has 125 frequencies, it is possible to realize point-to-point, Peer-to-multiple peer wireless communication, but also the design changing frequency and frequency hopping can be used to avoid other interference. 8051 kernels being internally integrated enhancement mode of NRF24E1, and it is provided with the wireless receiving and dispatching of 2.4GHz Device, 9 of 100kS/s and the analog-digital converter of 10, and be built-in with RC oscillator, SPI connects Mouth, UART interface, PWM output, house dog and wake up timer and special mu balanced circuit etc. up. All of high-frequency component includes that all portions such as oscillator are integrated in the inside of chip, so the performance of chip is the most steady Fixed, the least by the interference of external environment, antijamming capability is strong.

NRF24E uses 36 pin encapsulation, has less volume and low in energy consumption, is suitable for wanting power consumption and volume Use in the environment of asking strictly.Its transfer rate is very fast, and maximum up to 1Mb/s, sensitivity is-90 DBm, maximum transmitting power is 0dBm.As shown in Figure 8, for described signals collecting and transmission circuit Schematic diagram.

Aspect is realized for software, the crystal oscillator of 1MHz due to selected sensor internal band, D6 interface Receiving vibration signal, B interface receives the time data of DS1302.This single-chip microcomputer receives and is receiving host computer After gathering the request of signal, interrupt single-chip microcomputer to wake up up from the pattern of sleep by INIT0, and then issue Mono-ready signal " * " of nRF24E1.The when of initial NRF24E1, first have to the number of delivering letters " # ", after waiting until to confirm, calls launching procedure, data is sent to receiver module by USART, When monitoring the TXC position of UCSAR, it is sent, system entrance sleep state again. The software designed herein have employed the program language programming of LabVIEW, it is simple to realizes the system collection to data And analyzing and processing.And utilize computer to use LabVIEW program language, the emulation of complete pair signals, checking The correctness of design.

It is understood that for those of ordinary skills, can be according to technical scheme and basis Inventive concept in addition equivalent or change, and all these change or replace all should belong to appended by the present invention Scope of the claims.

Claims (10)

1. a blade structure for wind driven generator method for designing, it is characterised in that described method for designing includes:

A, use Weibull function model assessment wind speed, and according to the distribution curve of function model, determine startup Wind speed and rated wind speed；

B, the setting tip-speed ratio of blade, the number of blade, aerofoil profile and rotor diameter；

C, based on Wilson's method, calculate and obtain the chord length of foline, established angle and aerofoil profile.

Blade structure for wind driven generator method for designing the most according to claim 1, it is characterised in that institute State in step B, by following formula estimation rotor diameter:

P=CP (1/2) ρ P (3 π π D2/* η 1* η 2=0.49V13D2 η 1 η η

Wherein, P is wind driven generator output power, and V1 is the wind speed of design, and D is rotor diameter, and ρ is empty The density of gas, η 1 is the efficiency of generator, and η 2 is transmission efficiency.

3. the blade of wind-driven generator using method for designing as claimed in claim 1, it is characterised in that Described blade of wind-driven generator is NACA4412 aerofoil profile, and the number of blade is 3, and blade is equally divided into 18 Cross section.

Blade of wind-driven generator the most according to claim 3, it is characterised in that described wind-driven generator Blade is glass steel material.

Blade of wind-driven generator the most according to claim 3, it is characterised in that described wind-driven generator Blade also includes blade monitoring device；

Described blade monitoring device includes: gather the data acquisition unit of blade run signal；With data acquisition list Unit connects, and obtains described blade run signal, and carries out Logic judgment accordingly, output corresponding control signal Processor unit and being connected with described processor unit, obtains described control signal and performs corresponding operating Executing agency.

Blade of wind-driven generator the most according to claim 5, it is characterised in that described data acquisition list Unit includes the acceleration transducer obtaining blade vibration acceleration signal and obtains the rotating speed of wheel speed signal Sensor.

Blade of wind-driven generator the most according to claim 5, it is characterised in that described data acquisition list Analog to digital conversion circuit also it is disposed with between unit and processor unit；

After described blade run signal is converted to voltage signal, change through analog to digital conversion circuit, input to described place Reason device unit.

Blade of wind-driven generator the most according to claim 7, it is characterised in that described blade monitoring dress Put and also include a filter cell；

Described filter cell is connected with described processor unit, filters the signal that processor unit obtains；Described Processor unit, after filter cell processes, calculates signal frequency mean value and exports the control signal of correspondence.

Blade of wind-driven generator the most according to claim 8, it is characterised in that described filter cell Rejection frequency is at the signal in two stages of 1.7-1.75Hz and 3.05-3.2Hz.

Blade of wind-driven generator the most according to claim 8, it is characterised in that described filter cell is Active filter circuit.