CN113389859B - Wind generating set prediction type constant speed box system and constant speed control method - Google Patents

Abstract

The invention discloses a wind generating set prediction type constant speed box system and a constant speed control method, wherein the system comprises a planetary gear train, a control gear, a power source, an anemometer and a controller, wherein the outer circumference of a gear ring in the planetary gear train is provided with a gear surface meshed with the control gear, a planet carrier and a sun gear of the planetary gear train are respectively fixedly connected with a wind wheel shaft and a generator main shaft of the wind generating set, the power source is in transmission connection with the control gear, the controller is in control connection with the power source, the anemometer is arranged in the working environment of the wind generating set, and the anemometer is in signal transmission connection with the controller. According to the method, the wind wheel shaft rotating speed is obtained through the prediction of the controller according to the anemometer data, and then the rotating speed of the control gear is controlled through the power source, so that the rotating speed of the main shaft of the generator is kept constant to be a set target value. When external conditions change, the invention can obtain more stable output results through active control and better utilize wind energy to generate power.

Description

A predictive constant speed box system and constant speed control method for wind power generators

technical field

The invention relates to the field of constant speed control systems of wind power generators, in particular to a predictive constant speed box system and a constant speed control method of wind power generators.

Background technique

When the wind turbine generates power, the wind drives the impeller to rotate to form a mechanical torque, and then through the main shaft transmission chain, the gear box increases the speed to the speed required by the main shaft of the asynchronous generator, and generates power through the generator. The commonly used gear box has a constant speed ratio, so when the wind speed changes, the speed of the impeller will change, causing the speed of the main shaft of the generator to change after the gear box speeds up, and the frequency of the electric energy generated by the generator will fluctuate. As a result, the generated electric energy is reduced or directly loses its practical application value, and can only be used independently, and it is difficult to merge into the mainstream power grid.

At present, wind turbines use a gear box mechanism with a fixed speed ratio to increase the speed of the impeller. In the existing technology, a certain speed regulating mechanism is used to solve the speed change of the main shaft of the generator caused by the change of wind speed, so as to control the speed of the generator. The output is stable, and the common solution is to control the torque output of the impeller, and set the speed regulating mechanism by adopting measures such as impeller deflection, changing aerodynamic resistance, and adding pitch adjustment. But these speed regulation structures are not aimed at the gear box part of the transmission system, but to adjust the direction of the impeller or change the angle of the fan blade or change the pitch of the fan blade. The adoption of the above solutions not only increases the complexity of the mechanical structure, but also affects the strength of key components such as the impeller of the generator set, increases the probability of failure, and makes maintenance more difficult. At the same time, it also reduces the utilization efficiency of wind energy.

Contents of the invention

The purpose of the present invention is to provide a predictive constant speed box system and constant speed control method for a wind power generating set, so as to solve the problem of unstable frequency of output electric energy existing in the wind power generating set in the prior art when the wind speed changes.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A predictive constant speed box system for wind power generators, characterized in that it includes a planetary gear train, a control gear, a power source, an anemometer, and a controller, and the planetary gear train includes a ring gear, a sun gear, a planetary gear, and a planet carrier , the outer circumference of the ring gear is set as a gear surface, the planet carrier of the planetary gear system is fixedly connected with the wind wheel shaft of the wind power generating set, the sun gear of the planetary gear system is fixedly connected with the generator main shaft of the wind power generating set, and the control gear It meshes with the gear surface of the outer circumference of the ring gear in the planetary gear train, the power source is connected to the control gear, the controller is connected to the power source, the anemometer is set in the working environment of the wind turbine, and the anemometer is connected to the power source. The controller is connected for signal transmission, and the anemometer collects the wind speed data of the working environment of the wind power generating set and transmits them to the controller.

The predictive constant speed box system of a wind power generating set is characterized in that: the controller is electrically connected with a wind wheel speed sensor, and the wind wheel speed sensor works in cooperation with the wind wheel shaft of the wind power generating set, and is controlled by the wind wheel The rotational speed sensor senses the rotational speed of the wind rotor shaft in the wind power generating set and sends the rotational speed data to the controller.

The predictive constant speed box system of a wind power generating set is characterized in that: the controller is electrically connected with a main shaft speed sensor, and the main shaft speed sensor works in cooperation with the generator main shaft of the wind power generating set, and the main shaft speed sensor Sense the actual speed of the main shaft of the generator in the wind turbine and send the speed data to the controller.

A constant speed control method for a wind power generating set based on a predictive constant speed box system, characterized in that: the controller predicts the change of the shaft speed of the wind turbine in the wind generating set at the current wind speed according to the wind speed data measured by the anemometer combined with the gear ratio between the ring gear and the sun gear, and the gear ratio between the ring gear and the control gear, the speed of the control gear is controlled by the power source, and then the speed of the ring gear is controlled, so that in the wind power generating set The rotational speed of the main shaft of the generator remains constant at the set target value.

The constant speed control method of the wind power generator set is characterized in that: the controller controls the speed of the control gear based on the control formula, so that the speed of the main shaft of the generator in the wind power generator set remains constant as the set target value, and the control The formula is as follows:

n ₄ =b((1+a)(n ₃₊ Δn ₃ )-n ₁ )/a,

Among them: a is the gear ratio of the ring gear and the sun gear in the planetary gear train; b is the gear ratio of the ring gear and the control gear;

n ₁ is the rotational speed of the sun gear in the planetary gear system. Since the sun gear is fixedly connected to the generator main shaft of the wind power generating set, n ₁ is the target value that needs to be kept constant for the generator main shaft of the wind power generating set;

n ₃ is the current rotational speed of the planetary carrier in the planetary gear system. Since the planetary carrier is fixedly connected to the wind rotor shaft of the wind turbine, n ₃ is the rotational speed of the wind rotor shaft in the wind turbine measured by the wind rotor speed sensor;

Δn ₃ is the variation of the rotation speed of the planetary carrier. Since the planetary carrier is fixedly connected to the wind rotor shaft of the wind turbine, Δn ₃ is the variation of the rotation speed of the wind rotor shaft predicted by the controller based on the measurement data of the anemometer. The initial value of Δn ₃ is is 0;

n ₄ is the controlled rotational speed of the control gear.

The constant speed control method of the wind power generating set is characterized in that: the controller acquires the actual speed of the generator main shaft in the wind power generating set sensed by the main shaft speed sensor, combined with the need to keep the constant speed of the generator main shaft in the wind power generating set A target value is set to obtain a correction coefficient, and then the controlled speed of the control gear is corrected by the correction coefficient, so that the speed of the main shaft of the generator in the wind power generating set remains constant as the set target value.

The constant speed control method of the wind power generating set is characterized in that: the correction coefficient is set to c, and when the actual speed of the main shaft of the generator is greater than the set target value that needs to be kept constant, the controlled speed of the control gear is corrected as : (1+c)*The controlled speed of the control gear before correction;

When the actual rotational speed of the main shaft of the generator is lower than the set target value that needs to be kept constant, the controlled rotational speed of the control gear is corrected to: (1-c)*the controlled rotational speed of the control gear before correction.

For the objective environment where the wind speed is not controlled in the working environment of the wind power generating set, the system of the present invention constructs the transmission mechanism between the wind rotor shaft and the main shaft of the generating set through the planetary gear train, and at the same time builds the control gear for the ring gear in the planetary gear train Carry out speed control, and then realize the purpose of controlling the main shaft speed of the generator set. The method of the present invention utilizes the anemometer to measure the ambient wind speed to predict the wind speed data of the wind rotor shaft. According to the wind speed data measured by the anemometer, the rotational speed that the wind rotor shaft can reach at the current wind speed is predicted, and according to the predicted rotational speed of the wind rotor shaft, by controlling the gear Realize the control of the planetary gear train, and then keep the rotation speed of the main shaft of the generator constant at the set target value. Through the above-mentioned method, the electric energy output of the generator with stable frequency is finally obtained.

Compared with prior art, the advantage of the present invention is:

When the wind speed changes, the present invention can make the main shaft of the generator set output a stable rotational speed, so that the generator set can output electric energy with a stable frequency. The invention does not need to change the integrity of the impeller or adjust or change the deflection of the impeller, the installation angle or pitch of the blades, etc., reduces the complexity of the wind power generating set, increases the reliability, and improves the utilization efficiency of wind energy.

The invention simplifies the mechanical structure of the wind power generating set, applies electronic control technology to actively respond to changes in external conditions faster, and when external conditions change, more stable output results can be obtained through active control, and better utilization wind power generation.

Description of drawings

Fig. 1 is a schematic diagram of the system structure of the present invention;

Fig. 2 is a partial structural schematic diagram of the planetary carrier in the system of the present invention;

Fig. 3 is a flow chart of the method of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

As shown in Figure 1 and Figure 2, the predictive constant speed box system of the wind power generator of the present invention is composed of a gear box device and an electronic control system, wherein the gear box device includes a sun gear 4, a planetary gear 5, a planetary carrier 6, and a ring gear 7 The formed planetary gear train, as well as the wind wheel shaft 1, the control gear 8, and the generator main shaft 13.

In the present invention, the planetary gear system is a planetary gear system with four elements with indeterminate transmission ratios composed of sun gear 4, planetary carrier 6, ring gear 7 and control gear 8. The sun gear 4, planetary carrier 6, ring gear in the planetary gear system 7 all can be rotated. In the wind power generating set, the wind rotor shaft 1 and the planet carrier 6 are fixed coaxially on the rotation axis, or the fan shaft 1 may be fixed at a non-central position of the planet carrier 6 through a connecting piece. The wind turbine finds that the generator main shaft 12 and the sun gear 4 are coaxially affixed on the axis of rotation.

In the planetary gear train, in addition to the gears required by the planetary gear train, the ring gear 7 is provided with a gear surface on the outer circumference of the ring gear 7, and the control gear 8 meshes with the gear surface on the outer circumference of the ring gear 7.

The electronic control system is composed of the wind wheel shaft ring gear 2, the wind wheel speed sensor 3, the power source 9, the controller 10, the main shaft speed sensor 11, the generator main shaft ring gear 13, and the anemometer 14. Wherein, the power source 9 is an electric motor, or a hydraulic motor, or an air motor, or other mechanisms that can realize the rotation of the target component, and the output shaft of the power source 9 is fixedly connected to the control gear 8, specifically, the control gear 8 can be coaxially fixed on the The output shaft of the power source 9 may also be the output shaft of the power source 9 connected to the control gear 8 through other transmission mechanisms. In this embodiment, the power source 9 is a motor as an example. The wind wheel shaft ring gear 2 rotates synchronously with the wind wheel shaft 1, the wind wheel speed sensor 3 is placed on the side of the wind wheel shaft ring gear 2, the generator main shaft ring gear 13 rotates synchronously with the generator main shaft, and the main shaft speed sensor 11 is placed on the generator main shaft gear On the side of circle 13. The anemometer 14 is a vane-type anemometer, and the anemometer 14 is arranged in the working environment of the wind generator set, and the impeller of the anemometer 14 is installed in parallel with the impeller of the wind generator set for sensing wind speed signals. The wind wheel speed sensor 3, the main shaft speed sensor 11, the anemometer 14 and the power source 9 are electrically connected to the controller 10 through wires, and the controller 10 receives the data collected by the wind wheel speed sensor 3, the main shaft speed sensor 11, and the anemometer 14 respectively , and the controller 10 controls the rotational speed of the power source 9, thereby realizing the control of the rotational speed of the control gear 8.

In application, the impeller is connected to the wind rotor shaft 1, the generator main shaft 12 is connected to the main body of the generator, and the whole is placed on the support of the wind power generating set. Before starting to work, the power source 9 does not act and the control gear 8 does not rotate. At this time, the ring gear 7 is fixed, and the planetary gear train will have an initial transmission ratio according to its own gear parameters. When the wind blows the impeller to a certain speed, and accelerates the generator main shaft 12 to a predetermined rotational speed through the transmission, the whole system starts to work and sets the impeller to rotate at this speed. When the planetary gear train is at the initial transmission ratio , the speed value of the anemometer 14 corresponding to the steady rotation of the generator main shaft 12 .

As shown in FIG. 3 , it is a control flow chart of the constant speed control method of the wind power generating set of the present invention. When the wind speed changes, the speed of the anemometer 14 and the wind wheel will change accordingly, but because the moment of inertia of the anemometer 14 is much smaller than that of the wind wheel, the speed of the anemometer 14 will change faster than the speed of the wind wheel, and the wind speed can be sensed more accurately . The anemometer 14 transmits the wind speed signal to the controller 10 through wires, and the controller 10 calculates the speed of the wind wheel according to the moment of inertia of the impeller, and then according to the parameters set by the sun gear 4, the planetary carrier 6, and the ring gear 7, the three components are determined. According to the inherent law of the rotational speed between the sun gear 4 and the generator main shaft 12 at the set rotational speed, the rotational speed of the ring gear 7 is calculated, and the power source 9 is driven by a wire to drive the control gear 8 to rotate, and the control gear 8 is then driven The ring gear 7 rotates to make the planetary gear train obtain the transmission ratio under the current conditions in advance, so as to ensure that the rotating speed of the generator main shaft 12 is consistent with the rotating speed of the generator main shaft ring gear 13 .

The wind wheel speed sensor 3 senses the actual speed of the wind wheel through the wind wheel shaft ring gear 2 on the wind wheel shaft 1, and the actual signal of the main shaft speed sensed by the main shaft speed sensor 11 through the generator main shaft ring gear 13 on the generator main shaft 12 is also fed back to the controller 10. The controller 10 controls the power source 9 to drive the control gear 8 to correct the rotation speed of the ring gear 7 .

By continuously controlling the speed of the control gear 8, the present invention can keep the rotational speed of the main shaft 12 of the generator at a constant speed, and the output of the generator is electric energy with a constant frequency.

In the present invention, the rotational speed relationship between the wind rotor of the wind power generator and the impeller of the anemometer under the same wind conditions can be used to predict the change of the speed of the impeller of the wind power generator through the change of the speed of the anemometer, and then through the internal law of the gear box device The corresponding rotational speed of the ring gear 7 is calculated.

Set the moment of inertia of the wind rotor of the wind turbine as J ₁ , its speed is consistent with the speed of the planet carrier 6, set n ₃ , the speed variation within time Δt is Δn ₃ , and the effective area of wind force is S ₁ , then in Under the action of wind pressure p, the relationship between each parameter is as follows:

J ₁ Δn ₃ /Δt=p S ₁ ,

Similarly, if the moment of inertia of the impeller of the anemometer is J ₅ , its rotational speed is n ₅ , the velocity variation within time Δt is Δn ₅ , and the effective area of wind force is S ₅ , then under the same wind pressure p, The relationship between the parameters is:

J ₅ Δn ₅ /Δt=p S ₅ ,

Eliminate Δt and p from the above two formulas and arrange them to get:

Δn ₃ =(J ₅ /J ₁ )(S ₁ /S ₅ )Δn ₅ .

Therefore, based on the speed variation Δn ₅ of the impeller measured by the anemometer 14 , the variation of the rotational speed Δn ₃ of the rotor shaft 1 can be predicted.

In one round of control cycle, reassign the sum of the current speed and the variation of the wind rotor shaft 1 to the speed n ₃ of the wind rotor shaft 1, so that specific calculations can be performed during the control process, namely:

n ₃ =n ₃ +Δn ₃ .

Also as shown in Figure 2, in the gear box device in the predictive constant speed box system and control method of the wind power generator of the present invention, the speed of the sun gear 4 is set to _n1 , the speed of the ring gear 7 is _n2 , and the speed of the planetary carrier 6 The rotational speed is n ₃ , the rotational speed of the control gear 8 is n ₄ , the gear ratio between the ring gear 7 and the sun gear 4 is a, the gear ratio between the ring gear 7 and the control gear 8 is b, and the rotational speed of the sun gear 4 is n ₁ and the power generation The rotational speed of the machine main _shaft 12 is consistent, which is a fixed value in the application of the wind power generating set, and can be measured by the main shaft rotational speed sensor 11; Measurement; the rotational speed _n2 of the ring gear 7 is the controlled quantity; the rotational speed _n4 of the control gear 8 is the controlled quantity, which is obtained by the controller 10 controlling the power source 9 . According to the inherent law of the planetary gear system:

n ₁ +a n ₂ −(1+a)n ₃ =0,

In the case that the speed n ₁ of the sun gear 4 is a known set value, and the speed n ₃ of the planet carrier 6 rotates with the wind wheel, the speed n ₂ of the ring gear 7 can be calculated as follows:

n ₂ =((1+a)n ₃ -n ₁ )/a,

In order to obtain the rotational speed n ₂ of the ring gear 7, the controller 10 can calculate the rotational speed n ₄ of the control gear 8 from the meshing relationship between the ring gear 7 and the control gear 8:

n ₄ =b n ₂ =b((1+a)n ₃ -n ₁ )/a,

In practical applications, there will be a predicted variation Δn ₃ in the rotation speed n ₃ of the planet carrier 6 , which should also be included, so the controller 10 calculates the rotation speed n ₄ of the control gear 8 and should be corrected as:

n ₄ =b n ₂ =b((1+a)(n ₃ +Δn ₃ )-n ₁ )/a,

Then make the power source 9 run according to the rotation speed obtained, and the control method of the present invention can be realized.

In the actual operation of the predictive constant speed box system of the wind power generating set of the present invention, the rotational speed _n of the main shaft 12 of the generator obtained through calculation may deviate from the set value, and the controller 10 corrects the rotational speed n of the control gear 8 through the power source 9 ₄ to proceed. Set the correction coefficient of the speed _n4 of the control gear 8 as c, when the speed _n1 of the generator main shaft 12 is higher than the set value, the controller 10 corrects the actual speed of the control gear 8 to be (1+c) _n4 ; When the rotational speed n ₁ of the main shaft 12 is lower than the set value, the controller 10 corrects the actual rotational speed of the control gear 8 to be (1-c)n ₄ . During the operation of the passive constant speed box system of the wind power generating set of the present invention, the correction of the speed of the control gear 8 by the controller 10 will be carried out continuously, so as to ensure the output speed of the constant speed box under the condition that different wind speeds act on the wind wheel Can be stabilized at the set value.

The embodiments described in the present invention are only a description of the preferred implementation of the present invention, and are not intended to limit the concept and scope of the present invention. Various modifications and improvements made should fall within the protection scope of the present invention, and the technical content claimed in the present invention has been fully recorded in the claims.

Claims (5)

1. A wind generating set prediction type constant speed box system is characterized in that: the wind turbine generator system comprises a planetary gear train, a control gear, a power source, an anemometer and a controller, wherein the planetary gear train comprises a gear ring, a sun gear, a planet wheel and a planet carrier, the outer circumference of the gear ring is provided with a gear surface, the planet carrier of the planetary gear train is fixedly connected with a wind wheel shaft of a wind turbine generator system, the sun gear of the planetary gear train is fixedly connected with a generator main shaft of the wind turbine generator system, the control gear is meshed with the gear surface on the outer circumference of the gear ring in the planetary gear train, the power source is in transmission connection with the control gear, the controller is in control connection with the power source, the anemometer is arranged in signal transmission connection with the controller, and wind speed data of the working environment of the wind turbine generator system is collected by the anemometer and transmitted to the controller;

the control method of the wind generating set prediction type constant speed box system comprises the following steps:

the wind speed data measured by the anemometer is predicted by the controller to obtain the change quantity of the rotating speed of the wind turbine shaft in the wind generating set at the current wind speed, and the rotating speed of the control gear is controlled through the power source by combining the gear ratio of the gear ring and the sun gear and the gear ratio of the gear ring and the control gear, so that the rotating speed of the gear ring is controlled, and the rotating speed of the main shaft of the generator in the wind generating set is kept constant to be a set target value; the controller controls the rotating speed of the control gear based on a control formula, so that the rotating speed of the main shaft of the generator in the wind generating set is kept constant to be a set target value, and the control formula is as follows:

n ₄ = b ((1+a)(n ₃₊ Δn ₃ )-n ₁ ) / a，

wherein: a is the gear ratio of a gear ring and a sun gear in a planetary gear train; b is the gear ratio of the gear ring and the control gear;

n ₁ the rotation speed of the sun gear in the planetary gear train is n because the sun gear is fixedly connected with the main shaft of the generator of the wind generating set ₁ Namely, a set target value which is required to be kept constant for a generator main shaft of the wind generating set;

n ₃ as the current rotating speed of the planet carrier in the planet wheel system, n is as the planet carrier is fixedly connected with the wind wheel shaft of the wind generating set ₃ Namely the wind wheel shaft rotating speed of the wind generating set measured by a wind wheel rotating speed sensor;

Δn ₃ as the change of the rotating speed of the planet carrier, the planet carrier is fixedly connected with the wind wheel shaft of the wind generating set, so delta n is calculated ₃ Namely the wind wheel shaft rotating speed variation quantity, delta n, which is predicted by the controller according to the anemometer measuring data ₃ The initial value is 0;

n ₄ to control the controlled rotational speed of the gear.

2. A wind generating set predictive constant speed tank system as defined in claim 1, wherein: the controller is electrically connected with a wind wheel rotating speed sensor, the wind wheel rotating speed sensor is matched with a wind wheel shaft of the wind generating set in a working mode, and the wind wheel rotating speed sensor senses the rotating speed of the wind wheel shaft of the wind generating set and sends rotating speed data to the controller.

3. A wind generating set predictive constant speed tank system as defined in claim 1, wherein: the controller is electrically connected with a main shaft rotating speed sensor, the main shaft rotating speed sensor is matched with a main shaft of a generator of the wind generating set in a working mode, and the main shaft rotating speed sensor senses the actual rotating speed of the main shaft of the generator of the wind generating set and sends rotating speed data to the controller.

4. A wind generating set forecast constant speed tank system as claimed in claim 3, wherein: the controller obtains the actual rotation speed of the main shaft of the generator in the wind generating set, which is sensed by the main shaft rotation speed sensor, and combines the set target value, which is required to be kept constant, of the rotation speed of the main shaft of the generator in the wind generating set to obtain a correction coefficient, and then the controlled rotation speed of the control gear is corrected through the correction coefficient, so that the rotation speed of the main shaft of the generator in the wind generating set is kept constant to the set target value.

5. A wind turbine generator system predictive constant speed tank system as in claim 4, wherein: setting a correction coefficient as c, and correcting the controlled rotation speed of the control gear as follows when the actual rotation speed of the main shaft of the generator is larger than a set target value which needs to be kept constant: (1+c) the controlled rotational speed of the pre-correction control gear;

when the actual rotation speed of the main shaft of the generator is smaller than a set target value which needs to be kept constant, the controlled rotation speed of the control gear is corrected to be: (1-c) controlling the controlled rotational speed of the gear before correction.

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