CN103807096B - Wind turbine and control method thereof - Google Patents

Abstract

A kind of wind turbine and the method controlling this wind turbine.Described wind turbine includes blade, cabin, the electromotor being arranged in cabin, the wind speed tachymeter being arranged on top, cabin and the control system being arranged in cabin, described control system includes: be arranged on the yaw system of bottom, cabin, torque control module, driftage control module, current transformer, wherein, below rated wind speed, yaw system makes wind turbine be directed at wind direction, and control power by controlling tip-speed ratio, time more than rated wind speed, wind turbine is made to deviate wind direction by yaw system, and control the rotating speed of wind turbine, power of motor is made to be maintained at rated power.Wind turbine according to the present invention does not use the pitch-controlled system that fault rate is higher, thus the operational reliability of high wind turbine so that the design weight of wind turbine alleviates, and saves material and cost.

Description

Wind turbine and control method thereof

technical field

The present invention relates to a wind turbine, and more particularly, to a wind turbine without a pitch system and a control method thereof.

Background technique

Wind energy is an open and safe renewable energy, and the utilization of wind energy has been paid more and more attention at present. A wind turbine is a power generation device that relies on capturing wind energy and converting kinetic energy into electrical energy. Wind turbines are an important part of wind power plants.

Pitch system and yaw system are two important control systems to realize energy conversion of wind turbines. The pitch system keeps the output power constant above the rated wind speed by adjusting the pitch angle of the blades; the yaw system adjusts the windward angle of the nose through the wind vane on the top of the cabin, so as to track the change of wind direction in nature and achieve the maximum capture of wind energy the goal of.

In traditional wind turbines, components such as the pitch motor, the pitch reducer, and the pitch control cabinet are installed in the hub, and the power is controlled through the pitch system. However, due to the complexity of the pitch system, most of the electronic components and mechanical components rotate with the impeller in the hub, which is easy to cause damage; at the same time, electrical and control signals need to be transmitted from the nacelle through slip rings. According to statistics, the pitch system failure occupies the first place in the wind turbine failure statistics.

In addition, traditional wind turbines use passive control methods for turbine control, that is, input signals such as wind speed and wind direction are measured through the wind vane and anemometer on the roof of the nacelle, and then the input signals are transmitted to the main control system. Navigation system action to achieve stable operation. The pitch system is used to control the power output above the rated wind speed, which increases the complexity of the control system. Since it is necessary to transmit electrical signals and control signals from the stationary parts to the rotating parts, the slip ring system is required, which increases the probability of failure; at the same time, due to the The passive control state increases the design margin of the wind turbine, and the design safety factor increases, resulting in heavy weight and high price of the unit.

Contents of the invention

The object of the present invention is to provide a wind turbine and a power control method thereof. The wind turbine omits the vulnerable and expensive pitch system, and adjusts the windward direction through the yaw system to control the power of the wind turbine. When the power is below the rated power, the control system aligns the wind direction through the yaw control system according to the wind speed signal and wind direction signal measured by the anemometer, and notifies the converter to adjust the torque, and controls the impeller speed to keep the blade tip speed and wind speed signal. In the optimal tip speed ratio, so as to keep the blade working at the optimal power coefficient; when the rated power is above the rated power, according to the wind speed signal and wind direction signal measured by the anemometer, the yaw control system makes the impeller deviate from the inflow wind direction to varying degrees to maintain The power output is constant.

According to one aspect of the present invention, a wind turbine is provided, the wind turbine includes blades, a nacelle, a generator arranged in the nacelle, an anemometer arranged on the nacelle, a yaw system arranged at the lower part of the nacelle, a main A controller, a converter, a torque controller module and a yaw control module, wherein,

The anemometer measures the wind speed signal and wind direction signal, and inputs the wind speed signal and wind direction signal to the main controller. The main controller compares the current motor power with the rated power, and performs the following control operations:

If the motor power is below the rated power, calculate the wind direction signal deviation between the current moment and the previous moment, and control the yaw system through the yaw control module to align the blades with the wind direction based on the wind direction signal deviation; according to the wind speed and the optimal tip of the wind turbine Speed ratio, set the speed of the wind turbine, and control the converter to adjust the generator to the set speed through the torque control module, so as to control the power of the motor at the optimal power under the corresponding wind speed;

If the power of the motor is above the rated power, the yaw angle corresponding to the wind speed and the rated power is obtained according to the corresponding relationship between the wind speed, the yaw angle and the rated power, and the yaw system is controlled through the yaw control module according to the yaw angle and the wind direction signal , so that the blades gradually deviate from the wind direction; the torque control module obtains the torque corresponding to the rated power according to the relationship between torque and power, and informs the converter to adjust the torque of the generator to control the motor power to the rated power.

According to another aspect of the present invention, a method for controlling a wind turbine is provided, the wind turbine includes blades, a nacelle, a generator arranged in the nacelle, an anemometer arranged on the nacelle, a deflector arranged at the lower part of the nacelle Navigation system, main controller, converter, torque controller module and yaw control module, the method includes the following steps:

The anemometer measures the wind speed signal and wind direction signal, and inputs the wind speed signal and wind direction signal to the main controller, and the main controller compares the current motor power with the rated power;

If the motor power is below the rated power, the yaw control module calculates the deviation of the wind direction signal between the current moment and the previous moment, and controls the yaw system to align the blades with the wind direction based on the wind direction signal deviation; the torque control module according to the wind speed and wind turbine Optimal tip speed ratio, set the speed of the generator, and control the converter to adjust the generator to the set speed, so as to control the power of the motor to the optimal power under the corresponding wind speed;

If the power of the motor is above the rated power, the yaw control module obtains the yaw angle corresponding to the wind speed and the rated power according to the corresponding relationship between the wind speed, the yaw angle, and the rated power, and controls the yaw system according to the yaw angle and the wind direction signal, The blades are gradually deviated from the wind direction; the torque control module obtains the torque corresponding to the rated power according to the relationship between the torque and the power, controls the converter to adjust the torque of the generator, and controls the motor power to the rated power.

Wherein, the wind speed velocimeter is a laser radar velocimeter.

Wherein, the laser radar speed measuring instrument is arranged at the central axis of the top of the nacelle.

Wherein, in the process of controlling the yaw system to gradually yaw according to the obtained yaw angle and wind direction signal, the yaw angle can be dynamically adjusted.

Wherein, the wind speed signal and the wind direction signal may be an average wind speed signal and an average wind direction signal within a set time period.

The wind turbine does not use a pitch system with a high failure rate, but uses a front-mounted laser radar velocimeter to measure wind speed and wind direction signals, and the wind turbine control system performs active control according to the wind direction and wind speed signals, so that high wind The operational reliability of the turbine allows the design of the wind turbine to reduce weight, saving materials and costs.

Description of drawings

Through the following detailed description in conjunction with the accompanying drawings, the above-mentioned features and advantages of the present invention will become more clear, wherein:

1 is a schematic diagram of a wind turbine according to an exemplary embodiment of the present invention;

2 is a schematic diagram of a control structure of a wind turbine according to an exemplary embodiment of the present invention;

Fig. 3 is a control schematic diagram of a main control system of a wind turbine according to an exemplary embodiment of the present invention;

Fig. 4 is a graph showing the correspondence between wind speed, yaw angle and rated power.

detailed description

In order to solve the problem of high failure rate of the pitch system in the wind turbine in the prior art, the present invention proposes a wind turbine without the pitch system. In the case of no pitch change system, the blade pitch angle remains unchanged. That is, when the wind turbine blades are initially installed, a blade installation angle is determined. This installation angle ensures that the wind turbine can achieve the highest aerodynamic performance under a certain wind speed. efficiency.

In addition, the present invention designs a set of active control schemes, so that the control of the wind turbine is changed from passive wind control to active advance control, so that the turbine can move in advance before the wind load is felt, thereby avoiding damage to the turbine caused by strong winds or extreme wind conditions. parts are damaged. The realization of the active control system can realize the front wind speed measurement by installing the speedometer on the engine room, and achieve the power control effect through the yaw system.

The wind turbine of the present invention performs power control through the yaw system of the wind turbine instead of the pitch system, which is very different from the traditional wind turbine. Before the rated wind speed is reached, the speedometer installed on the nacelle measures the wind speed and direction signal of the incoming flow and transmits it to the main control system of the wind turbine. To achieve the control purpose of capturing the maximum wind energy coefficient; above the rated wind speed, measure the wind speed and wind direction signals of the incoming flow through the speedometer installed on the nacelle, and control the nacelle to deflect a certain angle in advance with the incoming flow, while the full power converter controls The main shaft torque keeps the power near the rated power, so as to achieve the purpose of power control.

Hereinafter, a structure of a wind turbine according to an exemplary embodiment of the present invention will be described in detail by referring to the accompanying drawings.

As shown in FIG. 1 , a wind turbine according to an exemplary embodiment of the present invention includes a tower 1, a nacelle 5 arranged on the tower 1, a hub 3 arranged at the windward end of the nacelle 5, blades 2 installed on the hub 3, The anemometer 4 arranged on the nacelle 5 , the yaw system (including the yaw drive generator 6 and the yaw bearing 7 ) arranged at the lower part of the nacelle, and the control system of the wind turbine arranged in the nacelle 5 .

In order to measure the wind speed and wind direction directly in front of the impeller, the anemometer 4 is installed at the top central axis of the nacelle 5 . In the example shown in FIG. 1 , the speedometer 4 is a lidar speedometer. The basic principle of the lidar speedometer is to use the Doppler effect, the instrument emits laser light to produce interference phenomenon, and measures the velocity of particles in the air to measure the wind speed. The reason why the laser radar speedometer is used is to use the characteristics of the laser radar speedometer to predict the wind direction and wind speed of the incoming flow in advance, and to carry out active control in advance. However, the present invention is not limited thereto, and any other type of anemometer capable of measuring wind speed and wind speed can also be used to realize the technical solution of the present invention.

The wind speed signal and wind direction signal measured by the lidar speedometer are used for the active control of the wind turbine, and the controller outputs the next moment of the wind turbine control signal, that is, the output speed or torque and yaw angle, so as to control the wind turbine power and windward direction.

Fig. 2 shows a schematic configuration of a control system of a wind turbine. As shown in FIG. 2 , the control system includes a torque control module 110 , a converter 120 , a yaw control module 140 , and a yaw system 150 . In addition, the control system also includes a main controller (not shown) for overall control.

Next, the control operation of the wind turbine according to the exemplary embodiment of the present invention will be described in detail with reference to FIG. 2 .

The laser radar velocimeter 4 measures the wind speed signal and the wind direction signal in real time, and sends the wind speed signal and the wind direction signal to the torque control module 110 and the yaw control module 140 in the control system, and the control system compares the current generator power with the rated power.

If the motor power at this time is below the rated power, the yaw control module 140 will calculate the wind direction signal deviation between the previous moment and the current moment, and then notify the yaw system 150 to track the wind direction, and perform yaw control to align the impeller with the wind direction, so as to Get maximum wind power. At the same time, the torque control module 110 will calculate the torque according to the input wind speed signal, the optimal speed ratio of the generator and the characteristic curve of the wind energy utilization coefficient, and compare it with the torque at the previous moment, so as to control the converter to pass The converter adjusts the rotation speed of the generator 130 so that the generator 130 can reach the optimal power corresponding to the wind speed at this time. This will be described with reference to steps 320 , 330 and 340 of FIG. 3 .

If the power at this time is above the rated power, the yaw module 140 will calculate the wind direction deviation between the previous moment and the current moment, and then notify the yaw system 150 to start yaw control to gradually deviate from the wind direction, and at the same time input the wind direction deviation signal to the steering wheel. Moment control module 110. The torque control module 110 calculates the torque at this time according to the input wind speed and wind direction deviation signals. According to the relationship between torque and power, the converter is notified to adjust the torque, and the yaw control module 140 is notified of the wind direction deviation to be adjusted, and the yaw system 150 adjusts the yaw angle. At this time, the power of the generator 130 is kept at the rated power through torque control and yaw control. This will be described in detail below with reference to steps 350 and 360 of FIG. 3 .

Fig. 3 is a control schematic diagram of a main control system of a wind turbine according to an exemplary embodiment of the present invention. Fig. 4 is a graph of the corresponding relationship between wind speed, yaw angle and rated power. A detailed description will be made below in conjunction with FIG. 3 and FIG. 4 .

In step S310, the controller obtains a wind speed signal and a wind direction signal by using a lidar speedometer to measure. Normally, the data measured by the anemometer in real time will be processed, for example, the average value of the wind speed signal and the wind direction signal over a period of time is taken, so the data obtained in step 310 contains most of the past data, and the change is relatively small compared to the wind speed The value measured by the instrument is smaller, which ensures that each yaw is small, ensures that the yaw system does not move frequently, and prolongs the life of the yaw system.

After obtaining the wind direction signal and wind speed signal, the main controller judges whether the current power is above or below the rated power.

If the current motor power is below the rated power, then in step 320, the torque control module sets the motor torque according to the current wind speed. Specifically, the torque control module calculates the blade tip speed according to the current wind speed and the optimal tip speed ratio of the wind turbine, so as to obtain the optimal rotation speed of the motor. Additionally, the torque control module measures the current generator speed (step 330 ). In step S340, the torque control module compares the set generator speed with the measured generator speed, calculates a speed deviation, and inputs the speed deviation signal to the controller. The main controller adjusts the motor speed through the converter according to the obtained motor speed deviation. At the same time, the controller controls the yaw system to align the nacelle with the wind direction according to the wind direction signal.

Since the wind turbine will have an optimal tip speed ratio after design, the optimal tip speed ratio can be used here to determine the torque of the motor. Tip speed ratio = blade tip speed/wind speed, the power curve of a wind turbine can be expressed as a curve of tip speed ratio and power coefficient, as long as the tip speed ratio is adjusted, the power coefficient can be controlled. The turbine needs to operate at the state with the maximum power coefficient. Therefore, when the wind speed is known, the blade tip speed can be obtained according to the optimal tip speed ratio, so as to obtain the optimal rotation speed of the motor. The rotation speed is set as the rotation speed of the motor, and the torque control module adjusts the rotation speed of the generator through the converter, so as to control the power of the motor to the optimal power.

If the current motor power is above the rated power, execute steps S350 and S360.

In step S350, the main controller obtains the yaw angle through a lookup table and the difference according to the obtained wind speed signal. Figure 4 shows the corresponding relationship between wind speed, yaw angle and rated power, and the lookup table can be obtained according to the relationship diagram.

When the power of the motor is greater than the rated power, the nacelle is controlled to deviate from the wind direction through the yaw system, so that the power of the motor is kept near the rated power. According to the corresponding relationship shown in Figure 4, when the controller obtains the wind speed signal, the yaw angle at the corresponding rated power can be obtained according to the wind speed signal, and then the nacelle can be adjusted to deviate from the wind direction according to the current wind direction signal.

As shown in Figure 4, according to the three input values, rated power, wind speed, and wind direction, two yaw angles can be interpolated. These two yaw angles are theoretically equal, but one is positive and the other is negative. value, which is the angle value corresponding to the wind direction to the left and to the right. If at this time the yaw position of the wind turbine is closer to one of the two positions, then the closer position is yawed.

In step S360, dynamically compensate the yaw angle by using the wind direction signal and wind speed signal measured in real time. The wind speed and wind direction in nature are constantly changing, and may change within a few seconds, so it is preferable to use the average value of the wind speed and wind direction signals within a period of time. The yaw response of the wind turbine is very slow. In addition, in order to avoid yaw fatigue, it should not yaw too fast. Usually, the wind speed and wind direction have changed as soon as the yaw enters a part, so the setting value of the yaw angle changes very quickly. quick. Therefore, during the yaw process, it is necessary to continuously adjust the yaw angle according to the real-time changes of wind speed and wind direction, that is, dynamically compensate the yaw angle.

The main controller adjusts the direction of the nacelle according to the dynamically compensated yaw angle so that the nacelle deviates from the wind direction. At the same time, the controller sets the motor speed corresponding to the rated power as the target speed of the motor, transmits the set speed to the converter, adjusts the reverse torque through the converter to adjust the generator to the set speed, and thus The power of the wind turbine is controlled around the rated power.

The wind turbine according to the present invention omits the pitch control system with a high failure rate, and achieves power control through the control of the laser radar velocimeter, the yaw system and the converter. The advantage of this is that the design margin of the wind turbine is reduced, the weight and cost are reduced, the complexity and failure rate of the pitch control system in the hub are reduced, and the system reliability is improved.

The invention can be applied not only to onshore wind turbines, but also to offshore wind turbines. In addition, although a three-blade wind turbine is shown in the drawings, the present invention is not limited thereto, and is also applicable to a horizontal-axis wind turbine.

Because the present invention saves the pitch changing system, therefore, the installation angle of the blade is constant. The initial installation angle is generally defined as follows: due to the different airfoils used by different wind turbine blades and the distribution of chord length and twist angle, the design of each wind turbine blade is different, which determines the different wind turbines. The initial installation angle is different. Of course, if the same blade is used, the initial installation angle is the same. Although the initial installation angles are different, the method of calculating the initial installation angles is common, but with different input data. The calculation of the initial installation angle is like this, which is determined by the dimensionless tip speed ratio and the aerodynamic efficiency of the blade (using the dimensionless tip speed ratio, you don’t need to consider the situation under different wind speeds, you only need to consider the tip speed ratio) , according to the design of the blade (including airfoil, chord length and twist angle distribution), use the BEM method (Blade Element Momentum Method) to calculate an optimal tip speed ratio and optimal blade aerodynamic efficiency, then The position of the blade at this time is the calculated installation position, then this position can be marked on the root of the blade, which is the calculated installation angle of the blade. When actually installing the blades, the blades will be installed according to this position, and then the wind turbine will be tested for a period of time to see if the generated power curve is consistent with the calculated power curve. If not, fine-tune the initial installation angle, usually 2 degrees Left and right, so that the actual power curve can be consistent with the calculated power curve.

Although the present invention has been described in conjunction with exemplary embodiments, the present invention is not limited to the above-mentioned specific embodiments, and various modifications and variations can be made to the above-mentioned embodiments without departing from the principle and spirit of the present invention.

Claims (10)

1. A wind turbine, characterized in that the wind turbine comprises a blade, a nacelle, a generator arranged in the nacelle, an anemometer arranged on the nacelle, a yaw system arranged in the lower part of the nacelle, a main controller, A converter, a torque controller module, and a yaw control module, wherein when the blades of the wind turbine are initially installed, the blades are installed at a predetermined angle that ensures the highest aerodynamic performance of the wind turbine at a predetermined wind speed efficiency, Among them, the wind speed anemometer measures the wind speed signal and wind direction signal, and inputs the wind speed signal and wind direction signal to the main controller, and the main controller compares the current motor power with the rated power, and performs the following control operations: If the motor power is below the rated power, calculate the wind direction signal deviation between the current moment and the previous moment, and control the yaw system through the yaw control module to align the blades with the wind direction based on the wind direction signal deviation; according to the wind speed and the optimal tip of the wind turbine Speed ratio, set the speed of the wind turbine, and control the converter to adjust the generator to the set speed through the torque control module, so as to control the power of the motor at the optimal power under the corresponding wind speed; If the power of the motor is above the rated power, the yaw angle corresponding to the wind speed and the rated power is obtained according to the corresponding relationship between the wind speed, the yaw angle and the rated power, and the yaw system is controlled through the yaw control module according to the yaw angle and the wind direction signal , so that the blades gradually deviate from the wind direction; the torque control module obtains the torque corresponding to the rated power according to the relationship between torque and power, and informs the converter to adjust the torque of the generator to control the motor power to the rated power. 2. The wind turbine of claim 1, wherein the anemometer is a lidar velocimeter. 3. A wind turbine according to claim 2, wherein the lidar velocimeter is arranged at the central axis of the nacelle roof. 4. The wind turbine according to any one of claims 1-3, wherein the yaw angle is dynamically adjusted during the process of controlling the yaw system to gradually yaw according to the obtained yaw angle and wind direction signals . 5. A wind turbine according to any one of claims 1-3, wherein the wind speed signal and wind direction signal are average wind speed signals and wind direction signals over a set period of time. 6. A method for controlling a wind turbine, the wind turbine comprising blades, a nacelle, a generator arranged in the nacelle, an anemometer arranged on the nacelle, a yaw system arranged at the lower part of the nacelle, a main controller, a variable A flow controller, a torque controller module, and a yaw control module, wherein, when the blades of the wind turbine are initially installed, the blades are installed at a predetermined angle, and the predetermined angle ensures that the wind turbine can achieve the highest aerodynamic efficiency at a predetermined wind speed , wherein the method includes the steps of: The anemometer measures the wind speed signal and wind direction signal, and inputs the wind speed signal and wind direction signal to the main controller, and the main controller compares the current motor power with the rated power; If the motor power is below the rated power, the yaw control module calculates the deviation of the wind direction signal between the current moment and the previous moment, and controls the yaw system to align the blades with the wind direction based on the wind direction signal deviation; the torque control module according to the wind speed and wind turbine Optimal tip speed ratio, set the speed of the generator, and control the converter to adjust the generator to the set speed, so as to control the power of the motor to the optimal power under the corresponding wind speed; If the power of the motor is above the rated power, the yaw control module obtains the yaw angle corresponding to the wind speed and the rated power according to the corresponding relationship between the wind speed, the yaw angle, and the rated power, and controls the yaw system according to the yaw angle and the wind direction signal, The blades are gradually deviated from the wind direction; the torque control module obtains the torque corresponding to the rated power according to the relationship between the torque and the power, controls the converter to adjust the torque of the generator, and controls the motor power to the rated power. 7. The method of claim 6, wherein the anemometer is a lidar velocimeter. 8. The method according to claim 7, wherein the lidar speedometer is arranged at the central axis of the roof of the nacelle. 9. The method according to claim 7 or 8, wherein in the process of controlling the yaw system to yaw gradually according to the obtained yaw angle and wind direction signal, the yaw angle is dynamically adjusted. 10. The method according to claim 7 or 8, wherein the wind speed signal and wind direction signal are an average wind speed signal and an average wind direction signal within a set period of time.