CN202768249U - Wind generation set control system based on pneumatic torque calculation model - Google Patents

Abstract

The utility model provides a wind turbine control system based on an aerodynamic torque calculation model, comprising: a laser radar speed measuring instrument installed on a hub for measuring the airflow velocity at a distance 2-3 times the diameter of the front impeller; a built-in torque PLC controller of controller, pitch controller, aerodynamic torque calculation module and controller given value correction module; and control power generation according to the corrected torque given value and pitch angle given value output by PLC controller Machine and impeller of wind turbine. The utility model enables the wind turbine control system based on the aerodynamic torque calculation model to respond to changes in wind speed in advance, corrects the effects of pitch change and torque control, improves the wind energy utilization rate of the wind turbine, and helps to solve problems caused by impeller inertia and pitch change. Fatigue load of the whole machine and loss of power generation caused by system delay.

Description

A Wind Turbine Control System Based on Aerodynamic Torque Calculation Model

technical field

The utility model relates to the technical field of wind power generation, in particular to a wind turbine control system based on an aerodynamic torque calculation model.

Background technique

In recent years, with the continuous progress of wind power generation-related control technologies, variable-speed and variable-pitch wind turbines have become the main installed type due to their advantages such as high efficiency of wind energy utilization and large single-unit capacity.

When the variable-speed variable-pitch wind turbine is at low wind speed (below the rated wind speed), the main control system adjusts the pitch angle of the blades to the optimum (or minimum), and adjusts the impeller speed by controlling the electromagnetic torque of the generator to make the wind turbine work at the optimum speed. In the state of optimal blade tip speed ratio, to achieve maximum wind energy capture; when the impeller speed reaches the rated speed, the speed cannot increase with the increase of wind speed, and it is necessary to increase the electromagnetic torque of the generator to keep the impeller speed near the rated speed. Make the wind turbine enter the constant speed region. When the wind speed increases to the rated wind speed, the torque reaches the rated value, and the generator reaches the rated power at the same time. At this time, if the wind speed continues to increase, the main control system will increase the pitch angle to reduce the captured wind energy and ensure that the generator set is not overloaded. Enter the constant power operation stage.

During the actual operation of the wind turbine, due to the existence of turbulence and gusts, the wind speed fluctuates all the time. To ensure that the wind turbine operates at the designed operating point, it is necessary to correctly control the generator torque and pitch angle according to the current wind speed. Due to the large moment of inertia of the impeller, changes in wind speed are reflected in the impeller speed, and then used to adjust the torque and pitch angle often lag behind for a long time. Especially when operating below the rated wind speed, in order to track the optimal tip speed ratio, it is necessary to continuously adjust the impeller speed according to the wind speed, but the torque at this stage in the existing main control system is the optimal value calculated according to the blade airfoil characteristics The product of the gain coefficient and the square of the generator speed is equivalent to an open-loop control method. The torque value obtained by this method is difficult to accurately track the optimal tip speed ratio, resulting in low wind energy utilization. When the wind speed is above the rated wind speed, controlling the pitch angle according to the speed of the impeller will also cause the pitch angle to not match the current wind speed at the impeller due to the change of the speed and the lag of the pitch system, so that the impeller and the tower bear a large load. Therefore, if the wind speed in front of the impeller can be measured and the aerodynamic torque at the impeller can be calculated in advance to correct the torque and the output of the pitch controller, it can not only ensure a higher wind energy utilization rate below the rated wind speed but also reduce the The fatigue load of wind turbines at high wind speeds has become one of the important research objectives in this field.

Utility model content

The purpose of this utility model is to use a wind turbine control system based on an aerodynamic torque calculation model. On the one hand, it can make the torque given value more reasonable when running below the rated wind speed, accurately track the best blade tip speed ratio, and improve Wind energy utilization; on the other hand, when operating above the rated wind speed, the size of the pitch angle can be adjusted reasonably in advance, effectively reducing the impeller and tower fatigue load and power generation loss caused by the gust at the impeller or the delay of the pitch system.

In order to solve the above-mentioned technical problems, the utility model provides a wind turbine control system based on an aerodynamic torque calculation model, including: a speedometer installed on the hub for measuring the airflow velocity at a distance of 2-3 times the diameter of the front impeller; a built-in The PLC controller of the torque controller, the pitch controller, the aerodynamic torque calculation module and the controller given value correction module; and the corrected torque given value and pitch angle given value output according to the PLC controller A wind turbine that controls the generator and impeller.

As a further improvement, the speed measuring instrument is a laser radar anemometer.

Compared with the prior art, the utility model has the following beneficial effects:

1. Introduce the relatively mature laser wind measurement radar to measure the wind speed in the direction of the incoming flow in front of the impeller, so that the wind turbine control system based on the aerodynamic torque calculation model can respond to changes in wind speed in advance;

2. Establish the aerodynamic torque calculation model of the impeller according to the airfoil parameters of the wind turbine, the optimal blade tip speed ratio and the optimal wind energy utilization coefficient, and use the speed of the airflow in front of the impeller and the current impeller speed and pitch angle of the fan Wait for the operating state to accurately calculate the aerodynamic torque that can be generated by the airflow in this section, correct the effect of pitch and torque control, and improve the wind energy utilization rate of the wind turbine;

3. According to the wind speed in front of the impeller, the output of the pitch control system can be adjusted in advance, which helps to solve the fatigue load of the whole machine and the loss of power generation caused by the inertia of the impeller and the delay of the pitch system.

Description of drawings

The above is only an overview of the technical solution of the utility model. In order to better understand the technical means of the utility model, the utility model will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a schematic composition diagram of a wind turbine control system with a laser radar anemometer and an aerodynamic torque calculation module of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is further described:

Please refer to Fig. 1, the utility model is a wind turbine control system based on an aerodynamic torque calculation model, including a laser radar anemometer, a PLC controller and a wind turbine.

Among them, the laser radar anemometer is installed on the hub to measure the airflow velocity at a distance of 2-3 times the diameter of the front impeller.

The wind turbine mainly includes a generator, a converter, a pitch system and an impeller, and the generator and the impeller are controlled according to the corrected torque given value and pitch angle given value output by the PLC controller.

The PLC controller, that is, the wind turbine controller based on the aerodynamic torque calculation model of the present invention, has a built-in torque controller, a pitch controller, an aerodynamic torque calculation module and a controller given value correction module. According to the wind turbine control method based on the aerodynamic torque calculation model of the present invention, the working process of the above modules includes the following steps.

Step 1: Obtain the airflow velocity V _Wind at a distance of 2-3 times the diameter of the impeller in front of the hub, the pitch angle β of the impeller at the current moment, and the rotational angular velocity ω _M of the generator through the lidar anemometer, the generator and the impeller, respectively, Calculate the aerodynamic torque at the impeller and calculate the corresponding electromagnetic torque.

At present, in the design process of wind turbines, the aerodynamic characteristics of the impeller are mainly analyzed according to the blade element theory. In order to be consistent with the design performance, the aerodynamic torque model based on the blade element theory is used to calculate and correct the output of the torque controller.

According to the blade element theory in aerodynamics and the concept of the actuator disk, the aerodynamic torque generated at the impeller is:

${\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&rho;</span>}{\mathrm{<span\; class="notranslate">\; ARUs</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}$

Where: ρ is air density;

A is the swept area of the impeller, which is A=πR ² ;

R is the impeller radius;

U is the wind speed at the impeller;

C _p (λ, β) is the wind energy utilization coefficient, λ is the tip speed ratio, and β is the pitch angle.

代换计算中的风速，从而得：Due to the complexity of the airflow around the blades, it is not reliable to directly use the wind speed to participate in the pitch controller and torque control in the main controller. Usually, according to the tip speed ratio, use:

Substituting the wind speed in the calculation, we get:

${\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; \&rho;</span>}{\mathrm{<span\; class="notranslate">\; \&pi;R</span>}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; )</span>}{{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; B</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Where ω _B is the rotational angular velocity of the impeller in rad/s.

Because in actual operation, the measurement accuracy of the impeller speed is not high, and usually the electromagnetic torque of the generator is used to control the operating state of the wind turbine, combined with the characteristics of the wind turbine transmission system, the impeller speed can be converted from the generator speed, and then calculated The corresponding generator electromagnetic torque is:

${\mathrm{<span\; class="notranslate">\; Q</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&pi;\&rho;</span>}{\mathrm{<span\; class="notranslate">\; R</span>}}^{\mathrm{<span\; class="notranslate">\; 5</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; \&beta;</span>}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}{\mathrm{<span\; class="notranslate">\; G</span>}}^{\mathrm{<span\; class="notranslate">\; 3</span>}}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}$

Where: ω _M is the rotational angular velocity of the generator;

G is the transmission ratio of the transmission gearbox.

In the process of wind turbine design, its operating point is often determined after the generator capacity and blade airfoil data are determined and corresponds to the wind speed, so the wind speed and the optimal tip speed ratio λ, pitch angle β and Correspondence table of wind energy utilization coefficient _CP , that is, by measuring the airflow velocity in front of the impeller, the λ and β when it reaches the impeller can be obtained, and then the corresponding torque Q _M can be calculated.

Step 2, obtaining the torque given value T _dem currently output by the torque controller.

Step 3, obtaining the pitch angle given value P _dem output by the current pitch controller.

Step 4: Correct the given value output by the torque controller or the pitch control through the controller given value correction module.

Specifically, if the power generated by the current wind turbine is below the rated power:

(1) When Q _M is less than the rated or maximum torque Q _E of the generator, then according to the difference between the calculated value Q _M and the current torque controller output T _dem ΔT=Q _M -T _dem , combined with the time when the airflow reaches the impeller t _W and the controller output cycle t _step , adjust the generator torque given value as T′ _dem =T _dem +(ΔT/t _W )×t _step . When Q _M is equal to Q _E , the correction is stopped.

(2) When Q _M is greater than the rated or maximum torque Q _E of the generator, it indicates that the wind speed is increasing, and the wind turbine is about to transition from below the rated power to above the rated power, and the corresponding measured wind speed V _Wind should be obtained from the table Design the pitch angle value P _des , calculate the difference with the current optimal pitch angle P _opt ΔP'=P _des -P _opt , combine the time t _W of the airflow reaching the impeller and the controller output cycle t _step , adjust the pitch angle Desired point

P' _dem =P _min +(ΔP'/t _W )×t _step

Among them, P _min is the minimum pitch angle.

Stop correcting the output of the pitch controller until the calculated aerodynamic torque of the impeller is the same as the rated torque or the output of the pitch controller is the same as the corrected pitch angle given value.

If the power generated by the current wind turbine is above the rated power:

(3) When Q _M is greater than the current torque value of the generator, it indicates that the wind speed in front of the impeller increases, and it is necessary to continue to increase the pitch angle to reduce the capture of wind energy at the impeller, and the measured wind speed V _Wind corresponding to the table should be obtained The difference between the pitch angle value P _des and the current P _dem at design time ΔP=P _des -P _dem , combined with the time t _W of the airflow reaching the impeller and the controller output cycle t _step to adjust the given value of the pitch angle P' _dem =P _dem +(ΔP/t _W )×t _step . Stop correcting the output of the pitch controller until the calculated aerodynamic torque of the impeller is the same as the rated torque or the output of the pitch controller is the same as the corrected pitch angle given value, so that the pitch system can respond to the increase of wind speed in advance , reducing the fatigue load.

(4) When QM is less than the current torque value of the generator, it indicates that the wind speed in front of the impeller decreases, and the pitch angle needs to be reduced to increase the capture of wind energy at the impeller, and the corresponding measured wind speed V _Wind should be obtained by looking up the table The difference between the pitch angle value P _des and the current P _dem at design time ΔP=P _des -P _dem , combined with the time t _W of the airflow reaching the impeller and the controller output cycle t _step to adjust the given value of the pitch angle P' _dem =P _dem +(ΔP/t _W )×t _step . Stop correcting the output of the pitch controller until the calculated aerodynamic torque of the impeller is the same as the rated torque or the output of the pitch controller is the same as the corrected pitch angle given value or reaches the minimum pitch angle, so that the pitch system It can respond to the reduction of wind speed in advance to avoid the loss of power generation.

The utility model provides a wind turbine control system based on an aerodynamic torque calculation model, which installs a laser radar wind speed measuring instrument at the hub of the wind generator set, and measures the wind speed at a distance of about 2-3 times the diameter of the impeller in front of the hub. Measurement, as the input of the aerodynamic torque calculation module; the aerodynamic torque calculation module calculates the aerodynamic torque that the impeller can produce in the future through the measured wind speed and the current speed and pitch angle of the impeller; the controller setting value is corrected Module, including generator torque given value correction and pitch angle given value correction, calculates the time when this part of the airflow reaches the impeller and the corresponding impeller aerodynamic torque according to the measured wind speed value, and the current torque controller The output comparison is used to correct the given value of generator torque and pitch, so that the fan can respond to the change of wind speed in advance. On the one hand, when the wind speed is below the rated wind speed, it can better track the optimal tip speed ratio and improve the utilization rate of wind energy; On the one hand, when operating above the rated wind speed, adjust the output of the pitch controller according to the relationship between the calculated torque and the rated (or maximum) torque of the generator, and respond to changes in wind speed in advance, thereby effectively reducing fatigue load or loss of power generation.

The above are only preferred embodiments of the present utility model, and are not intended to limit the present utility model in any form. Those skilled in the art may use the technical content disclosed above to make some simple modifications, equivalent changes or modifications. Within the protection scope of the present utility model.

Claims (2)

1. control system of wind turbines based on pneumatic torque calculation model is characterized in that comprising:

Be installed on the wheel hub, be used for measuring the tachometer of the place ahead impeller diameter 2-3 times distance airspeed;

Be built-in with the PLC controller of torque controller, change oar controller, pneumatic torque calculation module and controller setting value correcting module; And

According to the torque setting value through revising of PLC controller output and the wind-powered electricity generation unit of propeller pitch angle setting value control generator and impeller.

2. a kind of control system of wind turbines based on pneumatic torque calculation model according to claim 1 is characterized in that described tachometer is the lidar air speed measuring apparatus.

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