KR101894975B1 - Control system of Wind turbin - Google Patents

Abstract

The present invention relates to a control system for a wind turbine, and more particularly, to a control system for a wind turbine, which comprises a sensor unit for measuring a position angle of the rotor and a rotor speed value of the rotor, a high wind speed region gain scheduling unit, an actuator unit for driving and controlling the actuator, And a torque control scheduling unit according to the output control value by the pitch control unit. The system load is controlled by adding and subtracting the pitch angle according to the position of each blade through the high wind speed area PI scheduling according to the rotor position and rotation speed measurement values in the range exceeding the rated wind speed 1. A system for individual pitch control of each blade in a wind turbine that minimizes; A mode switch for selecting the high wind speed region gain scheduling unit and the transition wind speed region gain scheduling unit in addition to the high wind speed region gain scheduling unit and the mode switch for selecting the high wind speed region gain scheduling unit and the transition wind speed region gain scheduling unit, A pitch-saving pitch scheduling unit for transmitting an output value and a rotational speed value of the mode switch and a high-speed-transient wind speed setting mode information of the mode switch as input values to the actuator unit to correct and control the pitch angle values of the respective actuators; And a tower damper for correcting and controlling the pitch angle values of the individual actuators of the blades based on the tower moment values calculated by the calculation unit.

Description

Control system of wind turbine [0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control system for a wind turbine, and more particularly, to a configuration capable of further reducing the load on the wind turbine and further stabilizing the system by controlling the pitch of the blades individually in the wind turbine.

The horizontal axis wind turbine rotates the rotor by the blowing wind and produces electricity by the rotating rotor. As shown in FIG. 1, the wind blowing at this time is generally called wind shear. The larger the size of the wind power generator, or the higher the height of the tower, the greater the wind intensity.

In addition, when the wind field is viewed in a two-dimensional plane in a turbulent wind field actually blowing, as shown in FIGS. 1 and 2, wind intensities in all regions are also different. This means that as the overall area of the wind turbine (the area of the tower, the rotor rotation area) is widened, the wind intensity received by each area becomes different.

The above phenomenon is directly related to the load received by the blade or tower. When the blade azimuth angle is 0, the wind intensity is stronger than the wind speed at the hub height, and at 180 days it will be lower than the wind speed at the hub height. That is, when the blade load is compared with the azimuth angle of 0 and 180, it becomes zero.

Once installed, wind generators typically have a lifetime of 20 years. In order to maintain a lifetime of more than 20 years, it is necessary to stabilize the structure. In order to stabilize the structure, it is important to minimize the load applied to the structure.

In order to reduce the load of the entire wind turbine system, it is possible to design the structure to receive less load or to reduce the load using control technology.

It has been found that it is desirable to reduce the load by using the control technique because there is a limit in reducing the amount of output when structurally designing to receive less load.

In general, the control of the wind turbine is controlled by controlling the pitch angle of the blade at the rated wind speed or more to flow a certain amount of wind to reduce the load received by the wind.

It is common to use the Collective Pitch Control (CPC), which simultaneously adjusts the pitch of three blades. Integrated pitch control is controlled by sensing the rotational speed of the rotating rotor by wind force.

Integrated pitch control is commonly used. However, as the size of the wind turbine becomes larger, it is impossible to cope with the problem that the difference in load of the blades increases according to the above-mentioned altitude. A conventional control method for solving such a problem is the conventional IPC (Indivisual Pitch Control).

The concept of the individual pitch controller design is to minimize the magnitude of tilting and yaw moment components in the hub fixed coordinate system, which means that the controller should be designed to minimize the magnitude of the 1p component blade load in the blade rotating coordinate system.

The necessity of individual pitch control is to consider the difference of wind speed according to vertical altitude and horizontal movement distance disturbance, disturbance of wind speed by tower structure, turbulence characteristic of wind itself, consideration of yawing incompleteness and gravity effect of blade itself It can be done.

Conventionally developed individual pitch control is a control method in which the load is calculated according to the azimuth angle of each blade, and the pitch command value is input to each blade so that the pitch angles are operated differently for each blade.

Such a control method may be good in terms of load, but it is inevitable that the amount of output decreases in terms of performance.

In particular, Korean Patent No. 10-1375768, which is a system shown in Fig. 6, discloses a control system as shown in Fig.

A first controller for controlling an integrated blade pitch angle using a computed value and a limiter calculated by a PI controller for adding a rated angular velocity of the generator and a real time angular velocity of the generator; A second controller for controlling an individual blade pitch angle using a mechanical load value sensed in real time through a sensor installed in each blade; A third controller for determining a weight of an individual blade pitch angle that minimizes an objective function for maximum output and load reduction; And adding the integrated blade pitch angle controlled by the first controller to the weighted pitch angle calculated by multiplying the individual blade pitch angle outputted from the second controller by the individual blade pitch angle weight outputted from the third controller, And an operation unit for calculating a final pitch angle of the blade.

However, this prior art patent does not consider the control of the transition section from the high wind speed region to the low wind speed region by performing the individual pitch control without distinguishing the wind speed region, so that the mechanical vibration or the load imbalance occurs in such a transition portion Thereby shortening the life span.

In addition, there has been a problem in that proper control and load design can not be achieved by performing individual pitch control of the blades without considering vibration or load caused by wind power of the wind turbine tower itself.

Korean Patent No. 10-1375768 (Apr. 31, 2014) Korean Patent No. 10-11179633 (September 5, 2012)

Generally, the area of rotation of the rotor of the horizontal axis wind turbine is formed in a circle and the wind field is created. The higher the altitude on the ground, the greater the wind intensity by the wind shear, and the wind speed varies with the horizontal distance at the same elevation.

Accordingly, the strength of the wind speed is different in every region of the turbulence or the wind field, which results in different aerodynamic forces depending on the position of the rotor rotor. Conventional individual pitch control, which limits the output above the rated wind speed, is capable of controlling the output in a structure where the wind intensity due to rotational motion is affected differently in all areas, but the magnitude of the aerodynamic force applied to the blade in the wind field area is different There is a problem that the system is seriously affected by the load due to the load or the load applied to the system due to the influence of the load operated.

The present invention provides a structure for minimizing a load impact in a transition section between a high wind speed region and a low wind speed region which are power generation regions while performing individual pitch control and a means for reducing the load of the tower itself by further providing a damping means of the tower And the like.

A control system for a wind turbine according to the present invention has been developed in order to solve the above-mentioned problems of the prior art. The control system of the present invention measures the position angle of the rotor (0 degree to 360 degrees: a) and the rotor speed An actuator section 500 for driving and controlling the sensor section 100, the high wind speed region gain scheduling section 200 and the actuators A1, A2 and A3, an arithmetic section 600 and an output control value I And a torque control scheduling unit 700 according to the present invention is configured to control the system load by increasing / decreasing the pitch angle according to the position of each blade through the high wind speed region PI scheduling based on the rotor position and rotational speed measurement value in the section over the rated wind speed 1. A system for individual pitch control of each blade in a wind turbine that minimizes; A transition velocity range gain scheduling unit 300 in addition to the high wind speed region gain scheduling unit 200 and a mode switch for selecting the high wind speed region gain scheduling unit 200 and the transition wind speed region gain scheduling unit 300 And a high wind speed-transient wind speed setting mode information of the mode switch (400) as input values, an output value and a rotational speed value calculated from the torque control scheduling unit (700) A peak saving pitch scheduling unit 60 for transmitting a correction value to the actuator unit 500 and correcting the pitch angle values of the actuators A1, A2 and A3; a correction value calculation unit for calculating a correction value according to the tower moment value, And a tower damper 70 for correcting and controlling the pitch angular values of the individual actuators A1, A2, and A3 driven by the blades based on the calculated tower moment values.

Further, the tower damper 70 reduces the mechanical load of the tower structure itself. As a control algorithm for increasing the damping ratio of the primary vibration mode at the forward and backward motion loads of the towers, a phase compensation filter is applied, A 3-notch filter and a gain-scheduled PI controller are used as a phase compensation filter to reduce the magnitude of the load and the lateral bending moment,

The peak-saving pitch scheduling unit 60 corrects the actuator unit 500 based on the signal value from the torque control scheduling unit 700 and the output and the rotational speed value from the operation unit 600,

The rotor speed r of the rotor which is transmitted to the high wind speed region gain scheduling unit 200 and the transition wind speed region gain scheduling unit 300 is transmitted through a filter F such as a 3p notch filter or a band pass filter What is input is a characteristic of the limited configuration.

The control system of the wind turbine according to the present invention can provide a control system that reduces the load by minimizing the load load in the transition region of the high wind speed region and the low wind speed region as well as the high wind speed region in which power generation is performed.

Further, by providing the damping means of the tower itself, it is possible to control the tower by minimizing the load by reflecting the load, which is useful in increasing the lifetime of the residual wind turbine device and maximizing the output.

1 is an explanatory view showing a wind field applied to a blade in a wind turbine;
2 is an explanatory view for explaining control of a pitch angle value according to a blade position in a wind turbine;
3 is a graph illustrating the purpose of the control system of the wind turbine of the present invention.
4 is a block diagram illustrating a control system of a wind turbine of the present invention.
5 is a graph illustrating the effect of the control system of the wind turbine of the present invention.
Figure 6 is a block diagram of a system for performing individual pitch control in the high wind speed region of a conventional source.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a configuration and operation of a control system for a wind turbine according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an explanatory view showing a wind field applied to a blade in a wind turbine, FIG. 2 is an explanatory view illustrating control of a pitch angle value according to a blade position in a wind turbine, FIG. Fig. 4 is a block diagram illustrating the control system of the wind turbine of the present invention, Fig. 5 is a graph illustrating the effect of the control system of the wind turbine of the present invention, Explain.

The main idea proposed in the present invention is as follows.

In a control system structure of a wind turbine proposed as an output and pitch control method suitable for wind velocity or turbulence intensity,

The torque control loop employs a power transmission shaft damper to reduce the vibration of the rotary shaft due to the power transmission shaft motion mode and the blade in-plane motion mode. In order to smoothly control the transmission shaft damper of the torque control loop, The pitch control gains are applied by gain scheduling method which changes the values according to wind turbine operating conditions and consist of three control structures to reduce the load of the wind turbine blades and towers .

(1) Individual pitch control that reduces the size of the root portion mechanical load of a conventional blade

(2) a tower damper that acts to increase the damping ratio of the forward and backward motion modes of the tower structure,

(3) peak load reduction peak shaving controller at the time of pitch operation (transition section).

The ability to turn the pitch / torque control loop on and off appropriately according to the operating area of the wind turbine is very important. The pitch angle should be fixed to a fine pitch position under the rated operating conditions, and the pitch control loop should be operated normally when operating above the rated value.

If the pitch control loop does not accurately inform the pitch control information in the operating condition, a controller collision occurs in which the torque control and the pitch control system repeatedly keep the rotor rotation speeds at each other at a rated value. This is a control malfunction of the wind turbine, To prevent such simultaneous operation control, a mode switching signal is used to inform the pitch and torque control loop of appropriate pitch operation information. By using the mode conversion logic, it is possible to solve the problem that the torque PI control and the pitch PI control cause interference.

The blade (blade) that rotates by the aerodynamic force of the wind is less than the aerodynamic force of the blade passing through the peak when passing through the lowermost region. At the highest and lowest regions of the blade rotation, the aerodynamic load on the blade is asymmetric, And the blade passing through the highest point is very unstable in stability and is affected by system durability and reliability.

The pitch angle (β) is increased or decreased as the pitch angle (β) is increased or decreased from the center line of the rotor in the wind speed range above the rated wind speed, and when the maximum pitch angle value is determined at the highest point, And has a reference pitch value at the center axis of the rotor.

When the pitch angle (β) is reduced from the center value of the rotor in the wind speed range above the rated wind speed, the pitch angle (β) is reduced from the reference value and when the minimum pitch angle value is determined at the lowest point, And has a reference pitch value at the center axis of the rotor.

Therefore, the operation of the wind turbine control system to be implemented by the present invention is as follows.

(1) By calculating the measured wind speed, calculated wind shear, blade rotational angular velocity, rotor rotational speed, etc., the pitch angles of the rotating blades are determined differently from above and below the rotational center, So that the magnitude of the aerodynamic force applied to the rotor of each blade is made parallel.

(2) By varying the blade pitch angles passing through the rotor-blade pitch angle and the area above the central axis in the pitch system of each of the blades through the area below the center axis of the blades, the magnitude of the aerodynamic force exerted on the blades in the area of the wind field is mirrored Controls are equal to each other.

(3) By controlling different blade pitch angles above the rated wind speed, control is made to minimize the aerodynamic force and load applied to the wind turbine.

4 is a block diagram showing a control system of a wind turbine according to the present invention.

In the following description, each member includes an empirical and statistical logic portion, which is mostly composed of an algorithm, and the actuator portion 500 is a mechanical driving portion.

The control system of the present invention includes a sensor unit 100, a high wind speed region gain scheduling unit 200, a high speed wind speed region gain scheduling unit 300, a high wind speed region gain scheduling unit 200 A mode switch 400 for controlling the pitch angle beta c of the blades by initially driving one of the actuators A1, A2, and A3 of the actuator unit 500 by selecting any one of the gain and velocity gain region gain scheduling unit 300, An actuator unit 500 for driving and controlling actuators A1, A2 and A3 for driving and controlling a pitch angle beta of an actual blade, an arithmetic unit 600 and a torque control scheduling unit 700 as basic control logic, And a mechanical drive unit.

The high wind speed region gain scheduling unit 200 and the transition wind speed region gain scheduling unit 300 are general algorithms for performing PI gain scheduling.

The sensor unit 100 measures the position angle of the rotor (0 degrees to 360 degrees: a) and the rotor speed r of the rotor to the high wind speed region gain scheduling unit 200 and the transition wind speed region gain scheduling unit 300 And the rotor speed r of the rotor is input via a filter F such as a 3p notch filter or a band-pass filter (BPF).

A signal value is delivered to the operation unit 600 and used as a torque reference value, and the output control value is also input to the mode switch 400 And is used as a reference value for selection of the high wind speed region gain scheduling unit 200 and the transition wind speed region gain scheduling unit 300.

The blade pitch angle value selected by the mode switch 400 is transmitted to the actuator unit 500 to drive the actuators A1, A2, and A3 to perform pitch conversion or padding according to the load, And is calibrated and adjusted by the characteristic elements of FIG.

The characteristic configuration of the control system of the present invention is the peak value adjustment in the peak-saving pitch scheduling unit 60 described below. It is usually necessary to planarize the blade because it exhibits a load distribution that is mutually different in peak value when the blade is folded or paddled. For this purpose, a peak-saving pitch scheduling unit 60, which is also an algorithm, is employed.

The peak-saving pitch scheduling unit 60 takes the values from the torque control scheduling unit 700 and the output and rotation speed values calculated by the operation unit 600 as input variables and sends them again to the mode switch 400 The pitch-saving pitch scheduling unit 60 in the transition interval transmits a correction value to the actuator unit 500 to adjust the pitch angle values of the respective actuators A1, A2, and A3.

According to this operation, in the output-wind velocity graph of FIG. 3, the hezard is reduced in the transition region of high-low wind speed (wind speed 12m / s adjacent region).

The calculation unit 600 performs an operation based on the pitch angle values of the actuators A1, A2, and A3 from the actuator unit 500 and the torque from the torque control scheduling unit 700, And the respective individual pitch angle values are corrected by correcting the respective actuators A1, A2, and A3 of the actuator unit 500 as different pitch angle values.

In addition to this configuration, the characteristic control of the present invention includes:

A tower damper 70 (algorithm) calculates a correction value corresponding to a tower moment value from a sensor (not shown) installed on the tower, and calculates the blade moment of the individual actuators A1, A2, and A3) of each of the plurality of pixels.

The tower damper 70 is a control algorithm for reducing the mechanical load of the tower structure itself and increasing the damping ratio of the primary vibration mode at the forward and backward motion loads of the tower. The phase compensation filter is applied to the forward / The three-notch filter and the gain-scheduled PI controller are used as a phase compensation filter used in the tower damper 70, which can reduce the magnitude of the direction bending moment.

As a result of this design, the problem of inconsistency between the analytical mode frequency and the actual mode frequency, which may occur when the power transmission shaft damper is applied to an actual wind turbine, can be largely eliminated. It can be seen that the load peak is reduced by installing the tower damper 70 as in the case of the wind speed / db diagram as shown in FIG.

The output from the arithmetic unit 600 and the rotation correction signal are transmitted to the torque control scheduling unit 700 and the mode switch 400 again to become a base value for the determination of the mode switch 400 as an algorithm, and the torque control scheduling unit 700 and Is delivered to the peak-saving pitch scheduling unit 60 and used as a reference value.

The control system of the wind turbine of the present invention as described above has the advantage of reducing the load at the high-low wind speed transition section and enabling the load reduction design considering the influence of the tower itself.

100:
200: high wind speed region gain scheduling unit
300: Transient velocity region gain scheduling unit
400: Mode switch
500: Actuator part
600:
700: Torque control scheduling unit

Claims (5)

A sensor section 100, a high wind speed region gain scheduling section 200, and actuators A1, A2, and A3 that measure rotor position angles (0 to 360 degrees: a) and rotor rotor speed (r) And a torque control scheduling unit 700 according to a value of an output control (I) by a user's operation, so that the position and rotation speed of the rotor in the rated wind speed exceeding the rated speed range, 1. A system for individual pitch control of each blade in a wind turbine that minimizes system loading by increasing / decreasing the pitch angle according to a respective blade position through a high wind speed area PI scheduling by a measured value;
A transition velocity range gain scheduling unit 300 in addition to the high wind speed region gain scheduling unit 200 and a mode switch for selecting the high wind speed region gain scheduling unit 200 and the transition wind speed region gain scheduling unit 300 400,
The actuator unit 500 is controlled by using the value from the torque control scheduling unit 700, the output and rotation speed values calculated by the operation unit 600, and the high wind speed-transition air speed setting mode information of the mode switch 400 as input values. A peak-saving pitch scheduling unit 60 for correcting and controlling the pitch angle values of the actuators A1, A2, and A3,
And further includes a tower damper 70 for correcting and controlling the pitch angular values of the individual actuators A1, A2, A3 of the blades driven based on the tower moment values calculated by the arithmetic unit 600 by calculating correction values according to the tower moment values And a control unit for controlling the wind turbine. The method according to claim 1,
The tower damper 70 is a control algorithm for reducing the mechanical load of the tower structure itself and increasing the damping ratio of the structure in the primary vibration mode at the forward and backward motion loads of the towers as a phase compensation filter, Wherein the three-notch filter and the gain-scheduled PI controller are configured as a phase compensation filter to reduce the magnitude of the lateral bending moment. The method according to claim 1,
The peak saving pitch scheduling unit 60 corrects the actuator unit 500 based on the signal value from the torque control scheduling unit 700 and the output value and the rotation number value from the operation unit 600. [ Control system. The method according to claim 1,
The rotor speed r of the rotor which is transmitted to the high wind speed region gain scheduling unit 200 and the transition wind speed region gain scheduling unit 300 is transmitted through a filter F such as a 3p notch filter or a band pass filter And a control unit for controlling the wind turbine. The method according to claim 1,
Wherein the mode switch (400) is employed to prevent control malfunction of the wind turbine in which a controller collision occurs in which the torque control and the pitch control system overlap the rotor rotation speeds to maintain the rated rotor rotation speeds relative to each other. system.

Images