JP2005036749A - Horizontal axis windmill and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remarkably enlarge an installable area by suppressing the loss of a power generation amount and effectively suppressing low-frequency noise in a horizontal axis windmill. <P>SOLUTION: This horizontal axis windmill 1 comprises a rotational speed variable rotor 4 and in which the bearing of the rotor 4 is changed according to wind direction. The windmill comprises a recording means in which information (noise reference value excess area A) on low-frequency noise specific to the horizontal axis windmill 1 and information on a specific area B in which the low-frequency noise is suppressed are recorded, a timing means measuring times, a yaw angle measuring means measuring yaw angle, and a bearing measurement means measuring the bearing of the rotor 4. Also the horizontal axis windmill 1 comprises a rotational speed control means changing the rotational speed of the rotor 4 based on the information recorded in the recording means and the wind direction calculated by using the times measured by the timing means, yaw angles measured by the yaw angle measuring means, and/or the bearings measured by the bearing measuring means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a horizontal axis wind turbine and a control method thereof.

  Conventionally, a horizontal axis wind turbine including a rotatable main shaft extending in a substantially horizontal direction and a rotor with a variable rotation speed attached to the main shaft has been proposed and put into practical use (see, for example, Patent Document 1). .)

  In recent years, it is known that noise is generated due to the operation of the horizontal axis wind turbine described above. As such noise, “low-frequency noise (20 Hz) that has an audible sound“ wide band noise ”and a physical effect such as vibrating a window glass and the like and a psychological effect such as a headache and a feeling of pressure. Less than very low frequency noise).

Since these noises depend on the rotational speed of the rotor, conventionally, by adopting a method of changing the operation pattern day and night (hereinafter referred to as “prior art”) such as reducing the rotational speed of the rotor at night, the noise is reduced. Was suppressed. By adopting such a conventional technique, it is possible to suppress “wide band noise” which is an audible sound.
JP 2003-56448 A

  However, in the above-described conventional technology, since the propagation characteristics of low-frequency noise are not taken into consideration, the frequency of operation with an unnecessarily limited rotational speed of the windmill is increased, which may cause a loss of power generation. . In addition, even when the above-described conventional technology is adopted, “low frequency noise” having a propagation characteristic different from “wide band noise” may not be suppressed. Therefore, if there is a concern about the adverse effects of “low frequency noise”, the installation of the windmill must be abandoned, and there is a problem that the area where the windmill can be installed is limited.

  An object of the present invention is to significantly expand the installable area in a horizontal axis wind turbine by suppressing the loss of power generation amount and effectively suppressing low frequency noise.

  In order to solve the above problems, the invention according to claim 1 is a horizontal axis wind turbine having a rotor with variable rotation speed and changing the azimuth angle of the rotor according to the wind direction. Information relating to low-frequency noise, information relating to a specific region to be suppressed low-frequency noise, recording means recorded, time measuring means for measuring time, yaw angle measuring means for measuring the yaw angle, Azimuth angle measuring means for measuring the azimuth angle of the rotor, information recorded in the recording means, time measured by the time measuring means and / or yaw angle measured by the yaw angle measuring means and the azimuth angle Rotational speed control means for changing the rotational speed of the rotor based on the wind direction calculated from the azimuth angle measured by the measuring means.

  According to a second aspect of the present invention, in the horizontal axis wind turbine according to the first aspect, the rotational speed control means is configured to rotate the rotor when the specific region is located near the windward side or near the leeward side of the rotor. It is characterized by reducing the speed.

  According to a third aspect of the present invention, in the horizontal axis wind turbine according to the first or second aspect, when the rotational speed control means tries to suppress low-frequency noise in the specific region in a specific time zone, the specific The rotational speed of the rotor is reduced only in a time zone.

  According to a fourth aspect of the present invention, there is provided a horizontal axis wind turbine control method including a rotor having a variable rotational speed and changing an azimuth angle of the rotor according to the wind direction. And an information input step for inputting information relating to a specific region to suppress low frequency noise, a measurement step for measuring time and / or yaw angle and azimuth angle of the rotor, and the information input step A rotation speed control step for changing the rotation speed of the rotor based on the information input in step (b) and the wind direction calculated from the time and / or yaw angle and azimuth angle measured in the measurement step. It is characterized by providing.

  According to a fifth aspect of the present invention, in the horizontal axis wind turbine control method according to the fourth aspect, in the rotational speed control step, when the specific region is located in the vicinity of the windward side or the leeward side of the rotor, The rotational speed of the rotor is reduced.

  According to a sixth aspect of the present invention, in the control method for a horizontal axis wind turbine according to the fourth or fifth aspect, in the rotational speed control step, low frequency noise is to be suppressed in the specific region in a specific time zone. The rotational speed of the rotor is reduced only in the specific time zone.

  According to the first or fourth aspect of the present invention, information relating to low-frequency noise unique to the horizontal axis wind turbine (for example, propagation characteristics of low-frequency noise for each azimuth angle, distance from the rotor, and level of low-frequency noise). Information on correlation, correlation between rotor rotational speed and low-frequency noise level, etc.) and information related to specific area to which low-frequency noise is to be suppressed (for example, direction of specific area relative to rotor, specified from rotor) Based on the measured time and / or the wind direction calculated from the yaw angle and the azimuth angle), the distance to the region, the time zone in which the low frequency noise is to be suppressed in the specific region, and the like. The rotation speed can be changed.

  For example, based on the propagation characteristics of low-frequency noise that easily propagates to the windward and leeward side of the rotor, the rotational speed of the rotor is reduced when the specific area is located near the windward or near the leeward side of the rotor. Frequency noise can be effectively suppressed. In addition, when a specific area is located in a position where there is little influence from low-frequency noise (farther away from the windward side or farther from the leeward side or the outer circumference side of the rotor), the rotor is rotated at the normal speed to reduce the amount of power generation. Can be suppressed. In addition, when low frequency noise is to be suppressed in a specific area in a specific time zone (for example, at night), the rotor speed is reduced only in the specific time zone, thereby suppressing low frequency noise and generating power. Loss can be suppressed. Therefore, since low frequency noise can be effectively suppressed according to various situations, the area where the horizontal axis wind turbine can be installed can be greatly expanded.

  According to the invention described in claim 2 or 5, when the specific region is located in the vicinity of the windward side or in the vicinity of the leeward side of the rotor, the rotational speed of the rotor is reduced and low frequency noise is effectively suppressed. Can do.

  According to the invention of claim 3 or 6, when low frequency noise is to be suppressed in a specific region in a specific time zone, the rotational speed of the rotor is reduced only in the specific time zone. Low frequency noise can be effectively suppressed while suppressing loss.

  According to the present invention, the rotation of the rotor based on the information related to the low-frequency noise unique to the horizontal axis wind turbine, the information related to the specific area where the low-frequency noise is to be suppressed, and the measured time and / or wind direction. The speed can be changed. As a result, it is possible to suppress power generation loss and effectively suppress low-frequency noise, thereby greatly expanding the area where horizontal axis wind turbines can be installed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, the horizontal axis wind turbine 1 shown in FIG. 1 is adopted as an example of the horizontal axis wind turbine according to the present invention.

  First, the structure of the horizontal axis windmill 1 which concerns on this Embodiment is demonstrated using FIGS. 1-3. A horizontal axis wind turbine 1 is attached to a tower 2 installed at a predetermined position, a nacelle 3 attached to the top of the tower 2, a spindle supported by the nacelle 3 and extending in a substantially horizontal direction (not shown). The rotor 4 is provided (see FIG. 1).

  Inside the nacelle 3, a pitch variable mechanism that changes the pitch of the blades of the rotor 4, a control device that controls the rotational speed of the rotor 4 by driving and controlling the pitch variable mechanism, and low-frequency noise unique to the horizontal axis wind turbine 1. A memory as a recording means in which information relating to (hereinafter referred to as “low frequency noise information”), information relating to a specific area for which low frequency noise is to be suppressed (hereinafter referred to as “specific area information”), and the like are recorded, A clock or the like is provided as a time measuring means for measuring time.

  Further, an anemometer (not shown) as a yaw angle measuring means for measuring a yaw angle of the rotor 4 (an angle formed by the direction of the rotation axis of the rotor 4 and the wind direction in plan view) is provided outside the nacelle 3. An azimuth angle sensor (not shown) as an azimuth angle measuring means for measuring the azimuth angle of the rotor 4 is provided.

  The nacelle 3 and the rotor 4 are configured to rotate integrally around a tower 2 in a substantially horizontal plane. Therefore, based on the yaw angle measured by the anemometer and the azimuth angle of the rotor 4 measured by the azimuth sensor, the rotational surface of the rotor 4 is always substantially perpendicular to the wind direction (that is, the yaw angle is The nacelle 3 and the rotor 4 can be rotated so as to be about 0 °.

  The control device reads information (low frequency noise information and specific area information) recorded in the memory. Further, the time information measured by the clock, the yaw angle information measured by the anemometer, and the azimuth angle information of the rotor 4 measured by the azimuth sensor are input to the control device. Yes. The control device calculates wind direction information from the above-described yaw angle information and azimuth angle information. And the rotational speed of the rotor 4 is changed based on low frequency noise information and specific area information, time information, and / or wind direction information. That is, the control device is a rotation speed control means in the present invention.

  In the present embodiment, as low-frequency noise information in the memory, information related to low-frequency noise azimuth characteristics (information indicating a low-frequency noise level for each azimuth angle) and low-frequency noise distance characteristics information ( Information indicating the low-frequency noise level for each distance) and information relating to the correlation between the rotation speed of the rotor 4 and the low-frequency noise level.

  A graph showing the orientation characteristics of low-frequency noise is shown in FIG. In FIG. 2, the azimuth angle “0 °” indicates the windward direction perpendicular to the rotation surface of the rotor 4 in plan view, and the azimuth angle “180 °” is a plane with respect to the rotation surface of the rotor 4. The direction of the leeward side perpendicular to the eye is shown. The azimuth angle “90 °, 270 °” indicates the direction on the outer peripheral side of the rotor 4 perpendicular to the wind direction.

  The ratio between the low frequency noise level in the windward and leeward direction (0 ° and 180 °) of the rotor 4 and the low frequency noise level in the direction of the outer periphery side of the rotor 4 (90 ° and 270 °) is shown in FIG. As shown in FIG. That is, the low frequency noise has a characteristic that it is more likely to propagate in the windward and leeward directions (0 ° and 180 °) of the rotor 4 than the directions on the outer peripheral side of the rotor 4 (90 ° and 270 °). Yes. On the other hand, the wideband noise has a characteristic that it is relatively easy to propagate in the direction (90 ° and 270 °) on the outer peripheral side of the rotor 4 (see FIG. 2).

  A graph showing the correlation between the rotational speed of the rotor 4 and the low-frequency noise level is shown in FIG. FIG. 3A is a graph showing a low-frequency noise level (azimuth characteristic of low-frequency noise) for each azimuth, and FIG. 3B is a graph showing the horizontal distance and low frequency from the rotor 4 at an azimuth angle of 0 °. It is a graph which shows the relationship (distance characteristic of a low frequency noise) with a noise level. In both graphs, the rotational speed of the rotor 4 is set to 100% and 67%, and the correlation between the rotational speed of the rotor 4 and the low-frequency noise level is clarified.

  It is known that the low frequency noise level (dBG) greatly depends on the rotational speed of the rotor 4. As shown in FIGS. 3A and 3B, the low-frequency noise level can be greatly reduced only by reducing the rotational speed of the rotor 4 from about 100% to about 67%.

  For example, when the rotational speed of the rotor 4 is 100%, it is necessary to ensure a horizontal distance of about 180 m from the rotor 4 if the low frequency noise level is to be suppressed to a predetermined reference value (for example, 95 dBG) or less. On the other hand, when the rotational speed of the rotor 4 is 67%, it can be seen that the low-frequency noise level does not reach the reference value even in the vicinity of the rotor 4 (see FIG. 3B).

  Specific area information in the memory includes information related to the orientation of the specific area with respect to the rotor 4, information related to the distance from the rotor 4 to the specific area, information related to a time zone in which low frequency noise is to be suppressed in the specific area, etc. Can be mentioned. In the present embodiment, as the specific area information, information indicating that “the specific area B is located on the east side with respect to the rotor 4” and information indicating that “the distance from the rotor 4 to the specific area B is 150 m”. And “the time zone in which the low-frequency noise is to be suppressed in the specific region B is from 9 pm to 6 am” is employed.

  Next, the low frequency noise suppression operation by the horizontal axis wind turbine 1 according to the present embodiment will be described with reference to FIG.

  First, the control device of the horizontal axis wind turbine 1 reads low-frequency noise information recorded in the memory, and when the rotor 4 is operated at a normal speed, the low-frequency noise level exceeds a predetermined reference value (hereinafter referred to as “ Recognize “exceeding noise reference value”. Examples of the noise reference value excess region A are shown in FIGS. The noise reference value excess region A is larger in the direction of the windward side and the leeward side of the rotor 4 than in the direction of the outer periphery side of the rotor 4 due to the propagation characteristics of the low frequency noise (FIGS. 4A to 4C). reference).

  Further, the control device of the horizontal axis wind turbine 1 reads the specific area information recorded in the memory, and tries to suppress the low frequency noise in the specific area, the distance from the rotor 4 to the specific area, the orientation of the specific area with respect to the rotor 4. Recognize time zones, etc. Specifically, it recognizes that “the specific region B is located on the east side of the installation point of the horizontal axis wind turbine 1” (see FIGS. 4A to 4C). Further, “the horizontal distance from the horizontal axis wind turbine 1 to the specific area B is about 150 m”, and “the time zone in which the low frequency noise is to be suppressed in the specific area B is from 9 pm to 6 am”. recognize.

  Next, the control device of the horizontal axis windmill 1 calculates the wind direction from the yaw angle measured by the anemometer and the azimuth angle of the rotor 4 measured by the azimuth sensor, and the rotation of the rotor 4 with respect to this wind direction. The nacelle 3 and the rotor 4 are rotated so that the surface is substantially vertical (yaw angle of about 0 °) in plan view. The control device for the horizontal axis wind turbine 1 rotates the rotor 4 with reference to the noise reference value excess area A, the specific area B, the time measured by the clock, and the wind direction measured by the anemometer. Determine the speed.

  In the present embodiment, when the time zone is from 6:00 am to 9:00 pm (daytime), the rotor 4 is operated at a normal speed regardless of the noise reference value excess region A, the specific region B, and the wind direction.

  On the other hand, when the time zone is 9 pm to 6 am (nighttime), the rotational speed of the rotor 4 is changed based on the noise reference value excess region A, the specific region B, and the wind direction. For example, when the wind blows from the north to the south, the noise reference value excess region A greatly extends to the north side and the south side, which are the windward side and the leeward side, so the specific region B located on the east side of the horizontal axis wind turbine 1 Since it is not included in the reference value excess region A, the control device of the horizontal axis wind turbine 1 continues the operation without reducing the rotational speed of the rotor 4 (see FIG. 4A).

  In addition, when the wind blows from west to east, the noise reference value excess region A greatly spreads to the east and west, which are the windward and leeward sides, so the specific region B located on the east side of the horizontal axis wind turbine 1 is noise. It will be included in the reference value excess region A (see FIG. 4B). For this reason, the control device of the horizontal axis wind turbine 1 reduces the noise reference value excess region A by reducing the rotational speed of the rotor 4 so that the specific region B is not included in the noise reference value excess region A ( (Refer FIG.4 (c)).

  In the horizontal axis wind turbine 1 according to the embodiment described above, information (low frequency noise information) related to the low frequency noise unique to the horizontal axis wind turbine 1 and information related to a specific region in which the low frequency noise is to be suppressed (specific) The rotation speed of the rotor 4 can be changed based on the area information) and the measured time and wind direction.

  Specifically, when the specific region B is located in the vicinity of the windward side or in the vicinity of the leeward side of the rotor 4 (see FIG. 4B), the rotational speed of the rotor 4 is reduced to effectively reduce the low frequency noise. (See FIG. 4C). Further, when the specific region B is located on the outer peripheral side of the rotor 4 that is less affected by low-frequency noise (see FIG. 4A), the rotor 4 is rotated at the normal speed to suppress the loss of power generation. be able to.

  In the present embodiment, since the rotational speed of the rotor 4 is reduced only in the time zone (specific time zone: 9:00 pm to 6:00 am) in which low frequency noise is to be suppressed, low frequency noise is reduced. It is possible to suppress the loss of the power generation amount while suppressing it.

  The results of the low frequency noise suppression operation described above are shown in Table 1.

  When a conventional constant-speed horizontal axis wind turbine (Table 1: (a)) is used, the equipment utilization rate is high (30%) because the rotational speed of the rotor does not change with time. However, in order to suppress low-frequency noise, it is necessary to provide a distance (clearance) of about 180 m from the windmill.

  On the other hand, when a conventional variable speed horizontal axis wind turbine (Table 1: (b)) that reduces the rotational speed of the rotor at night is used, low frequency noise can be suppressed without providing a clearance. However, since the rotational speed of the rotor is reduced at night, there is a problem that the equipment utilization rate is reduced (26%).

  On the other hand, when the horizontal axis wind turbine 1 (Table 1 (c)) according to the present embodiment is employed, low frequency noise can be suppressed without providing clearance, and the wind direction is in a specific direction at night. Since the rotational speed of the rotor 4 is reduced only in the above, it is possible to suppress a decrease in equipment utilization rate (28%).

  In the embodiment described above, a mechanism for changing the rotation speed of the rotor by changing the pitch of the blade by the pitch variable mechanism is adopted. However, the rotation speed of the rotor is changed in two stages by changing the number of poles of the generator. It is also possible to adopt a two-stage rating method that can be set to

It is a conceptual diagram of the horizontal axis windmill which concerns on embodiment of this invention. It is an example of the low frequency noise information (graph which shows the azimuth | direction characteristic of a low frequency noise) recorded on the memory of the horizontal axis windmill shown in FIG. It is another example of the low frequency noise information (graph which shows the correlation with the rotational speed of a rotor, and a low frequency noise level) recorded on the memory of the horizontal axis windmill shown in FIG. It is explanatory drawing for demonstrating the low frequency noise suppression operation | movement by the horizontal axis windmill shown in FIG.

Explanation of symbols

1 Horizontal axis wind turbine 2 Tower 3 Nacelle 4 Rotor A Noise standard value excess area B Specific area

Claims (6)

In a horizontal axis windmill having a rotor with variable rotation speed and changing the azimuth angle of the rotor according to the wind direction
Recording means in which information relating to the low-frequency noise unique to the horizontal axis wind turbine and information relating to a specific region in which low-frequency noise is to be suppressed are recorded,
A time measuring means for measuring time;
A yaw angle measuring means for measuring the yaw angle;
Azimuth measuring means for measuring the azimuth of the rotor;
Wind direction calculated from the information recorded in the recording means, the time measured by the time measuring means and / or the yaw angle measured by the yaw angle measuring means and the azimuth angle measured by the azimuth angle measuring means Rotation speed control means for changing the rotation speed of the rotor based on
A horizontal axis wind turbine comprising: The rotational speed control means includes
2. The horizontal axis wind turbine according to claim 1, wherein the rotational speed of the rotor is reduced when the specific region is located near the windward side or near the leeward side of the rotor. The rotational speed control means includes
3. The horizontal axis wind turbine according to claim 1, wherein when the low frequency noise is to be suppressed in the specific region in a specific time zone, the rotational speed of the rotor is reduced only in the specific time zone. In a control method of a horizontal axis wind turbine having a rotor with a variable rotation speed and changing the azimuth angle of the rotor according to the wind direction,
An information input step for inputting information relating to the low-frequency noise unique to the horizontal axis wind turbine, and information relating to a specific region in which low-frequency noise is to be suppressed,
A measuring step of measuring time and / or yaw angle and azimuth angle of the rotor;
Rotational speed control for changing the rotational speed of the rotor based on the information input in the information input step and the wind direction calculated from the time and / or yaw angle and azimuth angle measured in the measurement step Process,
A method for controlling a horizontal axis wind turbine, comprising: In the rotational speed control step,
The horizontal axis wind turbine control method according to claim 4, wherein the rotational speed of the rotor is reduced when the specific region is located near the windward side or near the leeward side of the rotor. In the rotational speed control step,
6. The horizontal axis wind turbine according to claim 4, wherein when the low frequency noise is to be suppressed in the specific region in a specific time zone, the rotational speed of the rotor is reduced only in the specific time zone. Control method.

Images