A kind of wind power generating set rotational speed and torque control gear and method
Technical field
The present invention relates to control technology on wind electricity generation unit field, particularly a kind of wind power generating set rotational speed and torque control gear and method.
Background technique
When the control program of speed-changing oar-changing wind power generating set is low wind speed at present, adopt MPPT maximum power point tracking to control to obtain maximal wind-energy, during high wind speed, adopt change oar to control restriction wind energy and absorb to keep power invariability.Method shown in the more employing Fig. 1 of concrete enforcement.In figure, tri-sections of AB-BC-CD are the following rotational speed and torque relation curve of generator rating power, and the corresponding generator of A point reaches minimum grid-connected rotation speed n
1, DE section is for reaching rotational speed and torque relation curve after generator rating power, the corresponding rated power P of D point
r, corresponding generator speed is rated speed n
r.Wherein: AB section and CD section adopt pid control mode adjustment generator torque to make generator speed keep constant, and BC section adopts the best Cp control mode of tracking to adjust generator torque; DE section adopts permanent torque control mode to keep generator torque at rating value, calculates the mode that PI controls parameter (shown in Fig. 2) simultaneously regulate propeller pitch angle to make generator speed constant in rated speed by linear interpolation, thereby obtain firm power, exports.
This kind of mode can make wind power generating set with lower area, obtain maximal wind-energy at rated power to greatest extent in best Cp control zone, but also have the following disadvantages: 1) control of CD section and DE section conversion is at rated power point D, lack corresponding transition zone, because nature wind regime all exists with turbulence state, when wind speed rated wind speed up and down fluctuation can make torque and become oar to control frequent switching, owing to becoming oar control response speed, lag behind torque control, control the asynchronous rotating speeds that cause at n for two kinds
rthere is up and down larger fluctuation, thereby cause the impact to unit; 2) generated output power is the product of rotating speed and torque, impact due to turbulent wind, in DE section, become oar and control and can not maintain rotating speed completely at rating value, at this section, adopt permanent torque to control and will cause output power to change with generator speed, and reduce generated output quality; 3) mode that DE section adopts linear interpolation to calculate change oar PI controller parameter value can not effectively reflect the nonlinear aerodynamic characteristic of fan blade, thereby reduced, become the followability that oar action changes with wind speed, cause the fluctuation of speed of DE section larger, even occur that the unfavorable situations such as hypervelocity overload occur.
China Patent Publication No. CN101660489A discloses " a kind of megawatt wind generating set combination control policy ", this kind of control mode guarantees in synchronization torque processed and becomes oar control to only have a job, when wind speed variation is milder, can alleviate to a certain extent two kinds of frequent shortcomings of switching of controller in above-mentioned basic control scheme.But Megawatt fan wind wheel has larger inertia, when blower fan is worked below rated power point, wind speed sharply changes, cause that wind wheel accelerates to rise, because unit operation becomes oar when above to rated point, control and just devote oneself to work, add the impact that becomes oar response lag, this kind of control mode easily causes rotating speed and power to occur larger fluctuation, can cause the impact to unit equally.
Therefore, how a kind of wind power generating set rotational speed and torque controlling method is provided, realize near the torque of rated power and control and become the control of oar control flexible transition, guarantee the stability of unit operation and power stage thereof, become those skilled in the art's important technological problems urgently to be resolved hurrily.
Summary of the invention
In view of this, first goal of the invention of the present invention is to provide a kind of wind power generating set rotational speed and torque controlling method, realizes near the torque of rated power and controls and become the control of oar control flexible transition, guarantees the stability of unit operation and power stage thereof.
On the basis of above-mentioned wind power generating set rotational speed and torque controlling method, the present invention also provides a kind of wind power generating set rotational speed and torque control gear.
For achieving the above object, the invention provides following technological scheme:
A rotational speed and torque controlling method, is greater than rated speed at the measurement rotating speed of motor, and measures power and surpass in the situation of rated power, and torque is transformed into permanent power control mode by PI control mode; At change propeller angle, be less than the best propeller angle that becomes, and measure rotating speed and be down in the situation under rated speed, torque is transformed into PI control mode by permanent power control mode; Adopt PI to control parametrical nonlinearity adjustment mode and control change propeller angle, and in whole normal operation speed range, become oar control all in state of activation.
Preferably, get the intermediate speed n of generator
i/IIbetween the grid-connected rotation speed n of minimum
1with rated speed n
rbetween, establish the measurement rotational speed omega of generator between the grid-connected rotation speed n of minimum
1with intermediate speed n
i/IIbetween time situation under be interval I, measure rotational speed omega rotation speed n between
i/IIwith rated speed n
rbetween situation under be interval II, measuring in the situation that rotating speed is greater than rated speed is interval III;
In interval I, torque controller arranges generator reference rotation velocity and is: ω
n=n
1, maximum Cp is set simultaneously and follows the tracks of torque as limits value T
lim, when torque controller output, y is greater than T
limtime, torque limit is at y=T
lim; In interval II, torque controller arranges generator reference rotation velocity and is: ω
n=n
r, maximum Cp is set simultaneously and follows the tracks of torque as limits value T
lim, when torque controller output, y is less than T
limtime, torque limit is at y=T
lim;
Torque PI controller representation: y=y
*+ K
p-torque(x-x
*the K of)+(dT/2)
i-torque(x+x
*), x=ω-ω
n
Wherein: y is output torque, and x is input speed deviation, K
p-torquefor torque controller proportional gain, K
i-torquefor torque controller storage gain, dT is time step, and ω is generator measurement rotating speed, ω
nfor generator reference rotation velocity, symbol (*) represents each parameter respective value of a time point.
Preferably, in interval I, become oar controller and generator reference rotation velocity is set into ω
n=n
2, transition rotation speed n
2span be 1.01~1.02 times of rated speed n
r; In interval II, become oar controller and generator reference rotation velocity is set into ω
n=n
2; In interval III, become oar controller and generator reference rotation velocity is set into ω
n=n
r;
Become oar and control employing PI control parametrical nonlinearity adjustment mode, its representation is: y=y
*+ K
p-pitchg (φ) (x-x
*the K of)+(dT/2)
i-pitchg (φ) (x+x
*), x=ω-ω
nthis is wherein: y becomes propeller angle for output, and x is input speed deviation, K
p-pitchfor becoming the proportional gain of oar controller, K
i-pitchfor becoming oar controller storage gain, dT is time step, and G is nonlinear Control parametric gain, and φ is for becoming propeller angle, ω
ngenerator reference rotation velocity, symbol (*) represents each parameter respective value of a time point.
Preferably, intermediate speed n
i/IIvalue size is specially minimum grid-connected rotation speed n
1with rated speed n
rmean value.
A rotational speed and torque control gear, comprising:
Torque PI control module, for adopting PI control mode to adjust torque;
The permanent power control module of torque, for adopting permanent power control mode to adjust torque;
Become oar non-linearity PI control module, for adopting PI to control parametrical nonlinearity mode, adjust change propeller angle.
Preferably, also comprise region decision module, for judging the interval of current unit operation, according to different traffic coverages, select different torques to control reference rotation velocity and become oar to control reference rotation velocity.
From above-mentioned technological scheme, can find out, a kind of wind power generating set rotational speed and torque controlling method provided by the invention, in the II of setting area, become oar control rotating speed of target and be greater than torque control rotating speed of target, unit is increased with wind speed, generator speed is greater than rated speed, and while also not reaching rated power, torque still adopts PI to control, control change propeller angle and still can remain best angle according to rotation speed change, by changing two controllers at the control impact point of transition region, can avoid two kinds to control the asynchronous rotating speed that causes in the problem that larger fluctuation occurs up and down, transition region is changed to the curve after improvement by original point, the flexibility that more easily realizes state of a control is switched.Simultaneously, owing to not becoming the switch restriction of oar control, in whole normal operation speed range, become oar and control all in state of activation, transition zone between II, III, when wind speed changes steadily and generator speed is less than transition rotary speed area and makes to become propeller angle and remain at best angle; When wind speed occurs sharply to change, become oar control and can participate in advance controlling, control and coordinate rotating speed with torque, reduce the fluctuation of rotating speed in this region.
Meanwhile, unit adopts permanent power control mode controlling torque after reaching rated power, makes torque setting value rise and decline with generator speed, and with generator speed, decline and rise, thus the stability of guaranteed output output.
In addition, according to the adjustment of blade Nonlinear aerodynamics, become oar PI and control parameter, can strengthen the adaptability that becomes oar control and blade aerodynamic characteristic, improve and become the followability that oar action changes with wind speed, improve the stability of unit operation, reduce to control by becoming oar the fluctuation of speed causing, reduce the dynamic load of unit.
The present invention also provides a kind of wind power generating set rotational speed and torque control gear of having applied above-mentioned controlling method.
Accompanying drawing explanation
In order to be illustrated more clearly in the embodiment of the present invention or technological scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is that at present conventional wind power generating set is controlled rotary speed-torque graph of a relation;
Fig. 2 is that the conventional oar PI that becomes controls graph of a relation between parameter and propeller pitch angle at present;
After the improvement that Fig. 3 provides for the embodiment of the present invention, wind power generating set is controlled rotary speed-torque graph of a relation;
Fig. 4 controls graph of a relation between parameter and propeller pitch angle for the non-linear change oar PI that the embodiment of the present invention provides;
Fig. 5 control program of the present invention is implemented schematic block diagram;
Fig. 6 is that in embodiment 1, mean wind velocity is the wind speed schematic diagram of 11.7m/s turbulent wind;
Fig. 7 is the wind speed round comparison diagram that adopts respectively existing other control modes and controlling method of the present invention in embodiment 1;
Fig. 8 is the change propeller angle comparison diagram that adopts respectively existing other control modes and controlling method of the present invention in embodiment 1;
Fig. 9 is the generated output power comparison diagram that adopts respectively existing other control modes and controlling method of the present invention in embodiment 1;
Figure 10 is that in embodiment 2, mean wind velocity is the wind speed schematic diagram of 14m/s turbulent wind;
Figure 11 is the wind speed round comparison diagram that adopts respectively existing other control modes and controlling method of the present invention in embodiment 2;
Figure 12 is the change propeller angle comparison diagram that adopts respectively existing other control modes and controlling method of the present invention in embodiment 2;
Figure 13 is the generated output power comparison diagram that adopts respectively existing other control modes and controlling method of the present invention in embodiment 2.
Embodiment
The invention discloses a kind of wind power generating set rotational speed and torque controlling method, realize near the torque of rated power and control and become the control of oar control flexible transition, guarantee the stability of unit operation and power stage thereof.
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technological scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiments.Embodiment based in the present invention, those of ordinary skills, not making the every other embodiment who obtains under creative work prerequisite, belong to the scope of protection of the invention.
Refer to Fig. 3, the wind power generating set rotational speed and torque controlling method that the embodiment of the present invention provides, generator transition rotating speed is set and is greater than rated speed, measurement rotating speed at motor is greater than rated speed, and measure power and surpass in the situation of rated power, torque is transformed into permanent power control mode by PI control mode; At change propeller angle, be less than the best propeller angle that becomes, and measure rotating speed and be down in the situation under rated speed, torque is transformed into PI control mode by permanent power control mode; Adopt PI to control parametrical nonlinearity adjustment mode and control change propeller angle, and in whole normal operation speed range, become oar control all in state of activation.
The kind wind power generating set rotational speed and torque controlling method that the embodiment of the present invention provides, as shown in Figure 3, transition rotating speed point D ' is set in DE interval, when wind power generating set is during from state of a control CD to DE transition, become propeller angle and start to control variation from D ', and torque still adopts PI to control according to CD curve, by changing two controllers at the control impact point of transition region, can avoid two kinds to control the asynchronous generator speed ω that causes at rated speed n
rthe problem of larger fluctuation occurs up and down, and transition region is changed to the curve D D ' after improvement by original some D, and the flexibility that more easily realizes state of a control is switched.Meanwhile, owing to not becoming the switch restriction of oar control, become oar and control all in state of activation in whole normal operation speed range, transition zone between II, III, when wind speed variation is steady and generator speed ω is less than transition rotation speed n
rtime, make to become propeller angle and remain at best angle; When wind speed occurs sharply to change, become oar control and can participate in advance controlling, control and coordinate rotating speed with torque, reduce the fluctuation of rotational speed omega in this region.
Generated output power is the product of rotating speed and torque, due to the impact of turbulent wind, in DE section, become oar and control and can not maintain rotating speed completely at rating value, in the prior art, at this section, adopting permanent torque to control will cause output power to change with generator speed, reduce generated output quality.In order to address this problem, in the present embodiment, in the situation that measurement rotating speed is greater than or equal to transition rotating speed, torque is controlled and is adopted permanent power control mode, i.e. T
g=P
r/ ω, wherein T
gfor given generator electromagnetic torque, P
rfor generator rating power, ω is generator speed.
The kind wind power generating set rotational speed and torque controlling method that the embodiment of the present invention provides, in the situation that measurement rotating speed is greater than or equal to transition rotating speed, becomes oar control and adopts PI control parametrical nonlinearity adjustment mode to adjust change propeller angle.So, according to the adjustment of blade Nonlinear aerodynamics, become oar PI and control parameter, can strengthen the adaptability that becomes oar control and blade aerodynamic characteristic, improve and become the followability that oar action changes with wind speed, improve the stability of unit operation, reduce to control by becoming oar the fluctuation of speed causing, reduce the dynamic load of unit.
Refer to Fig. 3, get the intermediate speed n of generator
i/IIbetween the grid-connected rotation speed n of minimum
1with rated speed n
rbetween, establish the measurement rotational speed omega of generator between the grid-connected rotation speed n of minimum
1with intermediate speed n
i/IIbetween time situation under interval I, measure rotational speed omega rotation speed n between
i/IIwith rated speed n
rbetween situation under be interval II, measuring in the situation that rotating speed is greater than rated speed is interval III;
In interval I, torque controller arranges generator reference rotation velocity and is: ω
n=n
1, maximum Cp is set simultaneously and follows the tracks of torque as limits value T
lim, when torque controller output, y is greater than T
limtime, torque limit is at y=T
lim;
In interval II, torque controller arranges generator reference rotation velocity and is: ω
n=n
r, maximum Cp is set simultaneously and follows the tracks of torque as limits value T
lim, when torque controller output, y is less than T
limtime, torque limit is at y=T
lim;
Wherein: MPPT maximum power point tracking controlling torque restricted T
lim=K
optω
2; K
opt=η
mπ ρ R
5c
p/ (2 λ
3g
3), Kopt is for considering the optimal modal gain after Transmitted chains mechanical loss, η
mfor Transmitted chains mechanical efficiency, ρ is air density, and R is wind wheel radius, and Cp is peak output utilization factor, and λ is the optimum tip-speed ratio that maximum Cp is corresponding, and G is gear box ratio.
Torque PI controller representation:
y=y
*+K
p-torque(x-x
*)+(dT/2)K
i-torque(x+x
*),x=ω-ω
n
Wherein: y is output torque, and x is input speed deviation, K
p-torquefor torque controller proportional gain, K
i-torquefor torque controller storage gain, dT is time step, and ω is generator measurement rotating speed, ω
nfor generator reference rotation velocity, symbol (*) represents each parameter respective value of a time point.
Further, in interval I, become oar controller and generator reference rotation velocity is set into ω
n=n
2, concrete, transition rotation speed n
2span be 1.01~1.02 times of rated speed n
r; In interval II, become oar controller and generator reference rotation velocity is set into ω
n=n
2; In interval III, become oar controller and generator reference rotation velocity is set into ω
n=n
r;
Become oar and control employing PI control parametrical nonlinearity adjustment mode, its representation is: y=y
*+ K
p-pitchg (φ) (x-x
*the K of)+(dT/2)
i-pitchg (φ) (x+x
*), x=ω-ω
nthis is wherein: y becomes propeller angle for output, and x is input speed deviation, K
p-pitehfor becoming the proportional gain of oar controller, K
i-pitchfor becoming oar controller storage gain, dT is time step, and G is nonlinear Control parametric gain, and φ is for becoming propeller angle, ω
ngenerator reference rotation velocity, symbol (*) represents each parameter respective value of a time point.
Concrete, intermediate speed n
i/IIvalue size is specially minimum grid-connected rotation speed n
1with rated speed n
rmean value.
Control parametric gain G and become propeller angle
between relation table be shown
wherein
be the coefficient of being determined by blade Nonlinear aerodynamics, the change oar PI controller parameter of adjusting by this kind of mode is consistent with blade aerodynamic characteristic, as shown in Figure 4.
Each interval control logic conversion plan is described below:
From interval I, be transformed into interval II: generator speed ω > n
i/II;
From interval II, be transformed into interval I: generator speed ω < n
i/II;
From interval II, be transformed into interval III: generator speed ω > n
r, while P>=P
r, P is generated output power;
From interval III, be transformed into interval II: become propeller angle φ < φ
f2pwhile generator speed ω < n
r, φ
f2pvalue adds 0.5 deg for the best becomes propeller angle, and this value can be done suitable correction according to the aerodynamic characteristic of different leaves.
Control program of the present invention is implemented schematic block diagram as shown in 5.The generator speed of measuring is judged the region of current unit operation jointly with the vane propeller-changing angle of the generator power of measuring and measurement after by notch filter, according to different operation areas, select different torques to control and become oar to control reference rotation velocity, calculate respectively again each self-corresponding deviation, torque is controlled corresponding rotating speed deviation and is input to torque controller output torque value, the generator torque requirements that meets unit requirement by torque rate of change and torque extreme value restriction output is again controlled to generator, become rotating speed deviation and the change oar controller parameter after nonlinear adjustment that oar controller is corresponding and be jointly input to change oar controller, output becomes propeller angle, by becoming propeller angle and speed restriction output, meet again the change propeller angle of unit requirement.
The embodiment of the present invention also provides a kind of wind power generating set rotational speed and torque control gear, comprising:
Torque PI control module, for adopting PI control mode to adjust torque;
The permanent power control module of torque, for adopting permanent power control mode to adjust torque;
Become oar non-linearity PI control module, for adopting PI to control parametrical nonlinearity mode, adjust change propeller angle.
In order further to optimize above-mentioned technological scheme, also comprise region decision module, for judging the interval of current unit operation, according to different traffic coverages, select different torques to control reference rotation velocity and become oar to control reference rotation velocity.
The present invention is carried out to simulation run, adopt respectively near the turbulent flow of rated wind speed and specified above wind speed turbulent flow to carry out emulation comparison, wind power generating set main models parameter is in Table 1.
Table 1
Title |
Numerical value |
Unit |
Rotor diameter |
93 |
m |
Blade quantity |
3 |
- |
Hub height |
80 |
m |
Best propeller pitch angle |
0 |
deg |
Incision wind speed |
3 |
m/s |
Rated wind speed |
11.7 |
m/s |
Cut-out wind speed |
25 |
m/s |
Wind wheel normal running speed scope |
8.3~16.8 |
rpm |
Generator rated speed |
1755 |
rpm |
Generator rating power |
2100 |
kw |
Embodiment 1
Emulation adopts wind regime to be: mean wind velocity is 11.7m/s, and turbulence intensity is 9.45%, and simulation result is as Fig. 6~9, and in figure, thick lines represent controlling method result of the present invention, and hachure represents existing other controlling method results.Fig. 6 is wind speed, and Fig. 7 is wind speed round, and Fig. 8 is for becoming propeller angle, and Fig. 9 is power.From result figure, can find out, when wind speed fluctuates near rated wind speed, adopt controlling method of the present invention when the following wind speed of rated operation point rises suddenly, torque is coordinated to control with change oar and can be realized better the flexible conversion in control area, compare with existing other control modes, greatly reduce the fluctuation of rotating speed and power, improved the stability of unit under various wind regime, reduced the impact to unit.
Embodiment 2
Emulation adopts wind regime to be: mean wind velocity is 14m/s, and turbulence intensity is 10.01%, and simulation result is as Figure 10~13, and in figure, thick lines represent controlling method result of the present invention, and hachure represents existing other controlling method results.From result figure, can find out, when the above region of rated wind speed adopts constant-power control method of the present invention, can effectively realize the stability of power stage.Non-linear change oar is controlled parameter regulation means, realizes the nonlinear trend control that becomes oar action, has strengthened and has become the followability that oar action changes with wind speed, guarantees the stable operation of rotation speed of fan.Compare with existing other controlling methods, can obviously improve the stability of power stage and the stability of rotating speed, can effectively reduce the limit and the fatigue load of unit.
In this specification, each embodiment adopts the mode of going forward one by one to describe, and each embodiment stresses is the difference with other embodiments, between each embodiment identical similar part mutually referring to.
Above-mentioned explanation to the disclosed embodiments, makes professional and technical personnel in the field can realize or use the present invention.To these embodiments' multiple modification, will be apparent for those skilled in the art, General Principle as defined herein can, in the situation that not departing from the spirit or scope of the present invention, realize in other embodiments.Therefore, the present invention will can not be restricted to these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and features of novelty.