JP5098678B2 - Solar tracking device and tracking method for solar tracking device - Google Patents

Description

  The present invention relates to a solar tracking device and a tracking method for a solar tracking device, and more specifically, a solar power generation device in which a power generation module tracks the sun (in other words, faces the direction of the sun) and collects and generates power. The present invention relates to a solar tracking device that is preferably applied to a solar tracking device and a tracking method that can improve the tracking accuracy of the sun in this solar tracking device.

  As a type of solar power generation device, a tracking type solar power generation device is known. The tracking type solar power generation device is capable of tracking one or a plurality of power generation modules that generate power by receiving sunlight and the power generation module so that the sun can be tracked (that is, capable of rotating in the azimuth and tilt directions). And a supporting solar light tracking device. Then, the solar tracking device rotates the power generation module so that the light receiving surface thereof faces the sun (in other words, the light receiving surface of the power generation module is perpendicular to the axis of incident light from the sun). .

  Specifically, the power generation module includes a condensing lens that collects sunlight, and a solar cell (power generation cell) having a small area (compared to the condensing lens) that receives the collected sunlight and generates power. And other predetermined members. A condensing lens has a function which condenses the direct sunlight of a sun, and converges the condensed sunlight on the surface of a solar cell. For this reason, if the condensing lens (that is, the light receiving surface of the power generation module) does not accurately face the sun (in other words, the light receiving surface of the power generation module is accurate with respect to the axis of incident light from the sun). If it is not a right angle, the focused spot of the concentrated sunlight will deviate from the surface of the solar cell. If it does so, there exists a possibility that the efficiency of electric power generation may fall.

  Therefore, in the tracking type solar power generation device, it is preferable that the solar tracking device accurately tracks the sun and the light receiving surface of the power generation module is accurately opposed to the sun. However, it may be difficult to cause the power generation module to face the sun accurately due to an installation error at the time of installation of the solar power generation device.

  As a configuration in which the solar tracking device of the solar power generation device tracks the sun, for example, the solar tracking device includes a sensor that detects sunlight, and tracks the sun based on the intensity of sunlight detected by the sensor. The structure to do is known. That is, the configuration is such that the sun is positioned in the direction in which the sunlight detected by the sensor is the strongest, and the power generation module is directed in the direction. In addition to this, a configuration is also known in which the sun direction (azimuth angle and inclination angle) is calculated based on the date and time, and the power generation module is directed to the calculated direction. Furthermore, the structure which combined these two structures is also known.

  However, these configurations may have the following problems.

  A configuration including a sensor for detecting sunlight may misidentify the direction in which the sun is located due to the influence of the way the clouds come out (light cloudiness, background radiation becomes uneven, etc.) and surrounding buildings. For example, if the sun is hidden behind a cloud, the sensor loses its target. This makes it impossible to track the sun. In addition, when a cloud is present near the sun, the reflected light from the cloud may be brighter than the direct sunlight. In such cases, the sensor may mistake this cloud as the sun.

  In addition, when the cloud is thick overall, the thin part of the cloud may become brighter than the position where the sun exists. If this happens, the reflected light from thin and bright clouds and surrounding buildings may be mistaken for the sun. As a configuration for preventing such misidentification, for example, a configuration in which a light amount (light source) below a predetermined threshold is not tracked may be used. However, in this case, it is necessary to make individual adjustments for each photovoltaic power generation device (solar tracking device).

  On the other hand, in the configuration in which the direction of the sun is calculated based on the date and time, when a solar power generation device (solar tracking device) is installed, if there is a deviation in the installation direction or the like, the correction becomes extremely difficult. For example, even if the error is corrected so that the sun is accurately tracked at a specific date and time, the error may increase at other dates and times. In addition, it is difficult to accurately install a heavy structure such as a power generation module with an azimuth angle and an inclination angle.

  Therefore, it is necessary to correct the azimuth angle and the tilt angle so that the solar power generation device (solar tracking device) can accurately track the sun. As a configuration for correcting the azimuth angle and the inclination angle, for example, there are configurations described in Patent Literature 1 and Non-Patent Literature 1.

  Patent Document 1 discloses a configuration in which an azimuth angle and an inclination angle are corrected by correcting an error of a built-in clock in a configuration for calculating the direction of the sun based on the date and time. Specifically, the difference between the time in the south of the timepiece built in the solar power generation device (solar tracking device) and the time when the azimuth angle of the power generation module is true south is calculated. Based on this time difference, the built-in clock is corrected so that the power generation module accurately faces the sun.

  However, the configuration described in Patent Document 1 does not consider installation errors when installing a solar power generation device (solar tracking device). Therefore, as described above, even if the error can be corrected to accurately track the sun at a specific date and time, it may be possible that the error increases on the other date and time. .

  Non-Patent Document 1 discloses a configuration in which, in a configuration using a sensor, the direction of the sun is measured by an error sensor and the direction of the power generation module is corrected. However, with the configuration described in Non-Patent Document 1, it is considered difficult to eliminate the problems of the configuration using the sensor.

Japanese Patent Laid-Open No. 11-183446 Lique-Heredia et al., “CPV tracking systems: performance issues, specifications & design”, 4th ICSC, 2007

  In view of the above situation, the problem to be solved by the present invention is to provide a solar tracking device capable of correcting an installation error at the time of installation of a solar power generation device (solar tracking device), and a tracking method of the solar tracking device. It is to provide a solar tracking device that can accurately track the sun without always sensing the direction of the sun and a tracking method for the solar tracking device.

  In order to solve the above problems, the present invention is a solar tracking device of a concentrating solar power generation device including a power generation module that collects sunlight to generate power, and measures the azimuth angle α of the sun over time. Azimuth angle measuring means, a tilt angle measuring means for actually measuring the solar inclination angle η over time, and a position control means for performing position control for directing the power generation module toward the sun direction, the position control means, The sun's direction cosine (l, m, n) shown in the Cartesian coordinate system on the ground is a function of date and time that takes into account the theoretical direction cosine (ll, mm, nn) and correction parameters (δx, δy, δz). Position calculation formula setting means for setting as sum, angle acquisition means for acquiring azimuth angle α1 and inclination angle η1 which are actual measurement values from the azimuth angle measurement means and the tilt angle measurement means, and the acquired azimuth angle α1 And tilt angle η1, and the direction of the sun Correction parameter determining means for comparing the calculated azimuth angle α0 calculated from the string (l, m, n) with the inclination angle η0 and determining the correction parameters (δx, δy, δz) as constants. As the position control after the determination of the correction parameters (δx, δy, δz), the calculation formula (1) of the azimuth angle α0 and the calculation formula of the inclination angle η0 using the determined correction parameters (δx, δy, δz). The gist is to track the sun using (2).

  Here, l and m in Equation (1) are expressed by Equation (3) and Equation (4), respectively. Ω is the hour angle, δ is the solar declination, and φ is the latitude at which the solar tracking device is installed.

  Further, the present invention is a tracking method for a solar tracking device of a concentrating solar power generation device including a power generation module that collects sunlight to generate power, while the solar tracking device is in the sun. A step of actually measuring the actual azimuth angle and inclination angle of the sun, a step of cumulatively storing the measured azimuth angle and inclination angle, and a real sun based on the measured sun azimuth angle and inclination angle; Setting the direction cosine of (l, m, n) as the sum of the theoretical sun direction cosine (ll, mm, nn) and the date and time function taking into account the correction parameters (δx, δy, δz); Initializing the correction parameters (δx, δy, δz), calculated azimuth and tilt angles calculated from the stored azimuth and tilt angles and the sun's directional cosine (l, m, n) And the correction parameters (δx, δ determining y, δz) as a constant, replacing the initialized correction parameters (δx, δy, δz) with the determined correction parameters (δx, δy, δz), and determining and replacing as constants Storing the correction parameters (δx, δy, δz), and after storing the corrected correction parameters (δx, δy, δz) determined and replaced as constants, the azimuth angle α0 of the sun is stored. The gist is to track using Equation (5) and track the sun's tilt angle η0 using Equation (6).

  Here, l and m in Expression (5) are expressed by Expression (7) and Expression (8), respectively. Ω is the hour angle, δ is the solar declination, and φ is the latitude at which the solar tracking device is installed.

  ADVANTAGE OF THE INVENTION According to this invention, the installation error at the time of installation of a solar tracking apparatus can be correct | amended, for example, when it applies to a solar power collector, improvement in power generation efficiency can be aimed at. According to the present invention, the tracking error of the sun is corrected by software, so that correction is easy. Once the correction parameter is calculated, the sun can be accurately tracked without constantly sensing the sun.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is an external perspective view schematically showing a configuration of a solar power generation device including a solar tracking device 1 according to an embodiment of the present invention. As shown in FIG. 1, the solar tracking device 1 according to the embodiment of the present invention includes a support column 11, a horizontal rotation drive mechanism 12, a pair of left and right jacks 13, a position control unit 41, and an azimuth angle measurement unit 414. Inclination angle measurement means 415 and a control device (control panel) 14 are provided. The solar power generation device includes the solar tracking device 1 and the power generation module 2 according to the embodiment of the present invention.

  The support column 11 is a structure that stands vertically on the ground (foundation) 3. The horizontal rotation drive mechanism 12 is disposed at the tip of the column 11 and can rotate the power generation module 2 in the horizontal direction. Specifically, for example, a motor, a worm fitted to the rotation shaft of the motor, and a worm gear meshing with the worm are provided. The motor is fixed to the column 11, and the rotation shafts of the motor and the worm are arranged so as to face the horizontal direction. The worm gear is supported so as to be able to rotate in the horizontal plane with respect to the column 11 (that is, the rotation axis is vertical). The worm gear is coupled to the power generation module 2. Therefore, when the worm gear is rotated by the rotational power of the motor, the power generation module 2 rotates in the horizontal plane according to the rotation of the worm gear.

  The jack 13 includes a support shaft 131, and the support shaft 131 supports the power generation module 2 so that the inclination angle can be changed. Specifically, the support shaft 131 of the jack 13 is provided with a ball screw, and the support shaft 131 expands and contracts by the rotation of the ball screw. The tip of the support shaft 131 is coupled to the power generation module 2. The inclination angle of the power generation module 2 can be changed according to the expansion and contraction of the support shaft 131. Note that the solar tracking device 1 according to the embodiment of the present invention includes a pair of right and left jacks 13 in order to stably support the power generation module 2, and the power generation module 2 is configured by the pair of jacks 13. Supported. These left and right sets of jacks 13 operate in synchronization.

  The azimuth angle measuring means 414 can measure the azimuth angle of the sun. The tilt angle measuring means 415 can actually measure the sun tilt angle. Various known sun sensors can be applied to the azimuth angle measuring means 414 and the inclination angle measuring means 415.

  The position control unit 41 further includes a correction parameter determination unit 411, a position calculation formula setting unit 412, and an angle acquisition unit 413. The azimuth angle and inclination angle of the sun measured by the azimuth angle measurement means 414 and the inclination angle measurement means 415 are transmitted to the angle acquisition means 413. The position calculation formula setting means 412 converts the solar direction cosine (l, m, n) (represented by a column vector) shown in the orthogonal coordinate system on the ground into a theoretical direction cosine (ll, mm, nn) ( A product of a correction parameter (δx, δy, δz) (a combination of three constants and represented by a column vector) and a date / time function (this function will be described later); Set as the sum of The correction parameter determination means 411 compares the actual azimuth angle and inclination angle acquired by the angle acquisition means 413 with the calculated azimuth angle and inclination angle calculated from the sun direction cosine (l, m, n). Then, the correction parameters (δx, δy, δz) are determined as constants.

  The position control means 41, the azimuth angle measurement means 414, and the tilt angle measurement means 415 are mounted on the solar tracking device 1 when determining the correction parameters (δx, δy, δz), but the correction parameter determination means 411. After determining the correction parameters (δx, δy, δz), it is not necessary to be attached to the solar tracking device 1. That is, it is necessary only when determining the correction parameter.

  The control device 14 (control panel) controls the horizontal rotation drive mechanism 12 and a pair of right and left jacks 13. That is, the rotation angle (azimuth angle) and inclination angle in the horizontal plane of the power generation module 2 are controlled. The control device 14 (control panel) is attached to the column 11 as shown in FIG. The control device 14 includes storage means (not shown). This storage means can store the correction parameters determined by the correction parameter determination means 411. And the control apparatus 14 can be controlled, correct | amending an azimuth angle and a tilt angle based on the correction parameter which a memory | storage means memorize | stores.

  The power generation module 2 includes a condensing lens that condenses sunlight and a solar cell that receives the collected light and generates power. And it has the structure by which the several combination of a condensing lens and a solar cell is arranged in matrix form. As described above, the power generation module 2 is supported by the horizontal rotation drive mechanism 12 of the solar tracking device 1 so as to be rotatable in the horizontal plane, and is supported by the pair of right and left jacks 13 so that the inclination angle can be changed. The

  According to such a configuration, the solar tracking device 1 according to the embodiment of the present invention is based on the operation of the horizontal rotation drive mechanism 12 (adjustment of the rotation angle) and the operation of the pair of left and right jacks 13 (adjustment of the inclination angle). The power generation module 2 is supported so that the sun can be tracked.

  In the solar tracking device 1 according to the embodiment of the present invention, first, (1) a predetermined correction parameter is defined. (2) A correction parameter is calculated based on the true (ie, theoretical) direction cosine of the sun and the actual (ie, including error) direction cosine of the sun in the ground coordinate system. (3) The azimuth angle and tilt angle of the solar tracking device 1 are corrected based on the calculated correction parameter. It has the configuration.

  The cosine of the sun is assumed to be a straight line drawn from the origin (in this case, the installation position of the solar tracking device 1) toward the sun direction in the orthogonal coordinate system, the X axis, and the Y axis. The cosine component of the angle formed by the axis and the angle axis with the Z axis is represented by a vector having 3 elements.

  The true direction cosine of the sun in the terrestrial coordinate system (orthogonal coordinate system) (that is, the theoretical direction cosine that does not consider errors) is calculated as follows.

  FIG. 2 is a diagram schematically showing the positional relationship between the earth and the sun in the celestial coordinate system. In the celestial coordinate system, the sun apparently goes around the earth in one year. This solar orbit is the ecliptic, and the plane including the ecliptic is called the ecliptic plane. This ecliptic plane intersects with a plane including the celestial equator (this plane is called the equator plane) at an angle of 23.44 °.

  In this celestial coordinate system, the true direction cosine of the sun is given by equation (9).

  The angle δ in the equation (9) and FIG. 2 is an angle indicating the position of the earth on the elliptical orbit in the unit rad (that is, declination of view). This visual declination δ is calculated once a day. The visual declination δ is 23.44 ° in the summer solstice, −23.44 ° in the winter solstice, and 0 ° in the autumn and spring equities. This visual declination δ is calculated by Equation (10).

  The unit of equation (10) is rad. When the unit is converted to ° (deg), 180 / π = 57.29578 may be multiplied. In Equation (10), Γ = 2πn / 365. n is the number of days from the New Year starting from January 1st. However, Γ of February 29 of leap year is not different from that of February 28 (that is, n is not counted on February 29 in leap year). This equation (10) is an approximate equation that approximates that the orbit of the earth is an ellipse. The maximum error in this approximate expression is 0.05 °, and it is considered that tracking accuracy sufficient for practical use can be obtained. This equation (6) is called the Spencer equation, and is described in “New Solar Energy Utilization Handbook (Edited by Japan Solar Energy Society (2001))”.

  In order for the solar tracking device 1 according to the embodiment of the present invention to actually track the sun, it is necessary to know the direction of the sun as seen from the ground surface (that is, the installation location of the solar tracking device 1). Therefore, the coordinate system indicating the direction of the sun is converted (rotated) from the celestial coordinate system to the ground coordinate system.

  FIG. 3 is a diagram schematically showing the direction of the sun and the like in the ground coordinate system. The direction of the sun in the ground coordinate system changes (rotates) with the passage of time, with the Z axis in the celestial coordinate system as the rotation axis (that is, around the azimuth axis). This corresponds to the fact that the celestial body rotates with the passage of time around the North Star (ie, the celestial North Pole). Further, the zenith of the celestial coordinate system is rotated around the axis line in the east-west direction by (90 ° −φ °) in accordance with the latitude φ ° of the installation location of the sun tracking device 1. The direction of the rotated zenith becomes the zenith direction at the place where the solar tracking device 1 is installed (latitude = φ °).

  Therefore, the true direction cosine of the sun in the ground coordinate system is first converted into a coordinate system that rotates around the Z-axis direction according to time in the true direction cosine of the sun in the celestial coordinate system. Then, it is obtained by converting into a coordinate system rotated by (90 ° −φ °) in the Y-axis direction (inclination angle direction).

  The angle “rotates according to time around the Z-axis direction” is the hour angle ω. The hour angle ω is an angle obtained by measuring the direction of the sun along the orbit from the south-central direction in the orbit of the sun. Specifically, the south-central time is 0 ° and the hour is 15 °. Also, the morning is negative (minus) and the afternoon is positive (plus). The hour angle ω is calculated each time by the following equation (11).

  In Equation (11), θ is a time difference (unit: ° (deg)), L is the longitude (unit: ° (deg)) of the installation location of the solar tracking device 1, and T is time. For example, if the time is 8:45:25, the time T is given by T = 8 + 45/60 + 25/3600. This equality difference θ is a change depending on the date of sunrise and south-central time. Specifically, the equation of time θ is given by the following equation (12).

  The unit of equation (12) is rad. When the unit is converted to ° (deg), 180 / π = 57.29578 may be multiplied. This equation (12) is called the Spencer equation and is described in the “New Solar Energy Utilization Handbook (Edited by Solar Energy Society of Japan (2001))”. Γ is as described above. The maximum error in this equation (12) is 35 seconds (0.14 ° in terms of angle).

  From these, the true direction cosine of the sun converted from the celestial coordinate system to the ground coordinate system is calculated as follows. First, the theoretical cosine of the sun in the celestial coordinate system is converted to a coordinate system rotated by (−ω °) in the direction of the azimuth angle (around the Z axis), and then the tilt angle direction (around the Y axis) To a coordinate system rotated by (90 ° -latitude (φ) °).

  In general, a transformation matrix to a direction cosine in a new coordinate system rotated counterclockwise by an angle Θ as viewed from the positive direction of the Z axis is given by Equation (13). Similarly, the transformation matrix to the direction cosine in the new coordinate system rotated counterclockwise by the angle Θ as seen from the positive direction of the Y axis is given by Equation (14).

  Therefore, a matrix in which Θ in Equation (14) is replaced with (−ω) and a matrix in which Θ in Equation (13) is replaced with (90−φ) are expressed as a matrix (celestial coordinate system) shown in Equation (9). The true cosine of the sun at (). When these transformation matrices (Equation (13), Equation (14)) are applied to the theoretical cosine of the sun in the celestial coordinate system, Equation (15) is obtained. When this mathematical formula (15) is calculated, the mathematical formula (16) is obtained.

  This matrix (Equation (16)) is the true (ie, theoretical) direction cosine of the sun in the ground coordinate system.

  On the other hand, the direction cosine of the sun considering the installation error of the sun tracking device 1 (that is, the direction cosine including the correction parameter in the calculation formula) is calculated as follows. FIG. 4 is a diagram schematically showing a coordinate system schematically showing an installation error of the solar tracking device 1 and a correction parameter in this coordinate system. In FIG. 4, the solid line indicates the true vertical axis, the east-west direction axis, and the north-south direction axis. The broken lines indicate the actual vertical axis (rotation axis) and azimuth axis of the solar tracking device 1.

  Examples of the installation error of the solar tracking device 1 include the following. (A) Inclination of the azimuth axis (vertical axis) of the solar tracking device 1 from the actual vertical direction, (b) Inclination of the inclination angle axis of the solar tracking device 1 from the horizontal direction, (c) of the solar tracking device 1 Deviation between the direction of the azimuth axis and the direction of the actual azimuth axis, (d) Deviation between the direction of the inclination angle axis of the solar tracking device 1 and the direction of the actual inclination angle axis.

  (A) The inclination of the azimuth axis of the solar tracking device 1 from the vertical direction is an error that occurs when the vertical support of the column 11 that supports the power generation module 2 is insufficient when the solar tracking device 1 is installed. is there. It also occurs when the gear for rotating the power generation module 2 in the horizontal direction (azimuth angle direction) (the worm gear) is not strictly horizontal.

  (B) The inclination of the inclination angle axis of the solar tracking device 1 from the horizontal direction is, for example, an imbalance of the jack 13 that supports the power generation module 2 (specifically, the power generation module 2 is supported by a pair of right and left jacks 13). In such a configuration, the left and right jacks 13 are not balanced. It also occurs when the mounting accuracy of the bearing that supports the power generation module 2 around the tilt angle axis is insufficient.

  (C) The deviation between the direction of the azimuth angle axis of the solar tracking device 1 and the actual direction of the azimuth angle axis is insufficient for setting the azimuth of the solar tracking device 1 (that is, setting the direction of the east, west, north, and south of the solar tracking device 1 Is an error that occurs when the It also occurs due to a surveying error in the latitude of the installation location or a clock error.

  (D) The deviation between the inclination angle axis of the solar tracking device 1 and the actual inclination angle axis is an error caused by insufficient leveling of the solar tracking device 1 or a surveying error at the installation location.

  As described above, when such an installation error occurs (that is, when the solar tracking device 1 includes an installation error), as shown in FIG. 4, a coordinate system with reference to the true azimuth axis and the tilt angle axis. And the coordinate system set in the solar tracking device 1 do not match. That is, a deviation occurs between the coordinate system based on the true azimuth angle axis and the tilt angle axis and the coordinate system set in the solar tracking device 1.

  Therefore, in the embodiment of the present invention, the correction parameter is defined as follows. (1) Of the inclinations of the azimuth axis from the vertical direction, the direction sine in the north-south direction is δx. (2) Of the inclinations of the azimuth axis from the vertical direction, the direction sine in the east-west direction is δy. (3) The direction sine of the inclination angle axis from the horizontal direction is δz. (4) The offset of the azimuth axis is Δω. (5) Let the offset of the tilt angle axis be Δφ.

  Among these, (4) the offset Δω of the azimuth axis can be obtained by adjusting so that the solar condensing spot is positioned at the center in the north-south direction of the solar cell (or the concentrator) at the time in the south and middle. (5) The tilt angle axis offset Δφ is also obtained by adjusting the azimuth angle so that the solar condensing spot is positioned at the center in the east-west direction of the solar cell (or the concentrator) at the time in the south and middle. Therefore, the correction parameters determined by calculation are (1) the north-south direction sine δx of the inclination from the vertical direction of the azimuth axis, and (2) the east-west direction of the inclination from the vertical direction of the azimuth axis. Direction sine δy, and (3) the direction sine δz of the inclination angle axis from the horizontal direction.

  The reason why the above three correction parameters are determined by calculation is as follows. As shown in FIG. 4, the actual vertical axis of the solar tracking device 1 deviates from the true vertical axis. The correction parameters δx and δy are the sine component of the tracking error of the actual inclination angle and the sine component of the azimuth tracking error of the solar tracking device 1 with respect to the true vertical axis. That is, the deviation of the vertical axis is directly selected as a correction parameter. When the sine component of the north-south direction inclination and the sine component of the east-west direction inclination are known with respect to the true vertical axis, the deviation of the actual vertical axis of the solar tracking device 1 with respect to the true vertical axis is uniquely determined. .

  On the other hand, for the true inclination angle and the actual inclination angle of the solar tracking device 1, the sine component δz for one axis is selected as a correction parameter. Originally, the actual inclination angle of the solar tracking device 1 is also uniquely determined if the sine component with respect to the other two axes is selected as a correction parameter. However, in the determination (calculation) of correction parameters by fitting, which will be described later, if the number of variables to be obtained increases, coupling may occur. Therefore, the inclination angle is limited to a sine component for one axis, and three parameters δx, δy, and δz are defined as correction parameters as a whole. In this way, by limiting the number of correction parameters to three, subsequent correction parameter determination (calculation) can be performed easily and stably.

  The correction parameters δx, δy, and δz are not correlated with each other in terms of mechanism and mathematics. If there is no correlation with each other, there will be no influence on the correction parameter fitting calculation described later. Therefore, the correction parameter can be calculated stably. Moreover, it is necessary to be able to determine (calculate) the correction parameter stably regardless of the error. By using these three correction parameters, the correction parameters can be determined (calculated) stably in the determination (calculation) by fitting.

  When such a correction parameter is used, the sun direction cosine (that is, the sun direction cosine corrected by the correction parameter) considering the installation error of the solar tracking device 1 is given by Expression (17).

  Here, A, B, C, and V in Expression (17) are as follows.

  The first term on the right side (B in Equation (19)) in Equation (17) is the same as Equation (16) (that is, the true cosine of the sun). The matrix of the second term on the right side (matrix (matrix C in equation (20)) acting on the column vector (δx, δy, δz) consisting of correction parameters) is a function having the visual declination δ and the time angle ω as variables. is there. Since the declination δ and the time angle ω are variables that change according to the date and time, the matrix of the second term on the right side (matrix that acts on the column vector (δx, δy, δz) consisting of correction parameters) is the time. Is a matrix with The matrix C is a singular matrix whose value is substantially 0 (zero) at all dates and times.

  Therefore, the sun direction cosine corrected by the correction parameters δx, δy, and δz (A in Equation (17) and Equation (18)) is the true (theoretical) direction cosine of the sun and “time t is a function. And a product of “column vector (δx, δy, δz) consisting of correction parameters”. That is, it is expressed by a linear combination formula shown in Formula (22). The column vector (l, m, n) on the left side in Equation (22) is the directional cosine of the sun taking into account errors. The column vector (ll, mm, nn) of the first term on the right side is the theoretical sun direction cosine.

  The calculation process of Equation (17) and Equation (22) is as follows.

A conversion vector to a direction cosine in a new coordinate system in which a certain unit vector n (n ₀ , n ₁ , n ₂ ) is used as a rotation axis and rotated around the positive rotation direction by an angle Ω is generally expressed by a mathematical expression. (23)

Using this equation, a coordinate transformation matrix is obtained with axes inclined by δx, δy, and δz. That is, the column vector (0, 1-δz ² , δz) is substituted into (n ₀ , n ₁ , n ₂ ) of Equation (23), and (90 ° −φ °) is substituted into Ω. Then, the following equation (24) is obtained.

  Of these terms in the matrix, if a second-order or higher term is ignored as being minute (assuming the value of the second-order or higher term is zero), Equation (25) is obtained.

Also, the column vector (δx, δy, (1-δx ² -δy ² ) ^1/2 ) is substituted into (n ₀ , n ₁ , n ₂ ) of Equation (19), and (90 ° −φ is substituted for Ω) Substitute °). Then, if a second-order or higher term is ignored as being minute (assuming the value of the second-order or higher term is zero), Equation (26) is obtained.

  When these coordinate transformation matrices are applied to the direction cosine of the sun position in celestial coordinates, the direction cosine when the axis is shifted is obtained. Specifically, it is expressed as the following mathematical formula (27).

  In the expression thus obtained, the second and higher terms of each term are ignored as being minute (the values of the second and higher terms are set to zero), and are combined with a vector (δx, δy, δz). And expressed by the following formula (28).

  The matrix of the first term on the right side of Equation (28) is the same as Equation (16). That is, the first term on the right-hand side is the true (theoretical) direction cosine of the sun. The matrix acting on the column vector (δx, δy, δz) consisting of the correction parameter of the second term on the right side is a function having the visual declination δ and the time angle ω as variables. Further, since the visual declination δ and the time angle ω are variables determined by the date and time, the matrix of the second term on the right side (the matrix acting on the column vector (δx, δy, δz) consisting of the correction parameters) is the time. Is a matrix with

  Thus, the direction cosine of the sun taking into account the installation error (the direction cosine of the sun with correction parameters added to the calculation formula) is the true (theoretical) direction cosine, the matrix and the correction as a function of time. It can be organized into the sum of the product of column vectors (δx, δy, δz) consisting of parameters.

  Then, the tilt angle η1 corrected by the correction parameter is given by Equation (29), and the azimuth angle α1 corrected by the correction parameter is given by Equation (30). Note that l and m in Equation (30) are given by Equation (31) and Equation (32), respectively.

  Equation (29) of the inclination angle η1 is the inverse sine function of the third row on the right side of Equation (27). Since the Z-axis component of the sun direction cosine is a sine function (sine function) of the tilt angle, the inverse function of the sine function of the direction cosine is the sun tilt angle η1. The inclination angle η1 is 0 ° at sunrise and sunset.

  Equation (30) of the azimuth angle α1 is an inverse function of the tangent function of the value obtained by dividing the second row on the right side of the equation (27) by the first row on the right side. That is, in general, the direction cosine is expressed by Equation (30). Here, α is an azimuth angle and η is an inclination angle. Dividing the second row by the first row gives the value tanα. Therefore, the inverse function of the tangent of the value obtained by dividing the second row on the right side by the first row on the right side is atan (tan α), and the azimuth angle α1. When the first line on the right side is negative (minus value), the value of the azimuth angle α is made positive (plus) by adding 180 °.

  Next, a method for determining (calculating) the correction parameters δx, δy, and δz and a method for correcting the solar tracking device 1 according to the embodiment of the present invention will be described. FIG. 5 is a flowchart showing a procedure for determining (calculating) the correction parameters δx, δy, and δz and the correction method of the solar tracking device 1 according to the embodiment of the present invention.

  In step S1, the solar tracking device 1 according to the embodiment of the present invention is installed. The sun tracking device 1 is equipped with a position control means 41, an azimuth angle measurement means 414, and an inclination angle measurement means 415. The installed sun tracking device 1 may have an installation error. That is, as described above, the inclination of the azimuth axis (vertical axis) from the actual vertical direction, the inclination of the inclination angle axis from the horizontal direction, the deviation between the direction of the azimuth axis and the direction of the actual azimuth axis, In some cases, a deviation between the direction of the tilt angle axis and the actual direction of the tilt angle axis is included. For this reason, the correction parameters δx, δy, and δz may not actually be zero. Therefore, in order to determine (calculate) the correction parameters δx, δy, δz, in this step S2, the values of the correction parameters δx, δy, δz are set to 0 (zero) as initial values.

  In step S3, adjustment is performed so that the inclination of the horizontal position of the solar tracking device 1 according to the embodiment of the present invention becomes zero. For this adjustment, for example, an adjustment using a level can be applied.

  In step S4, the tilt angle is adjusted (the tilt angle axis offset Δφ is adjusted). Specifically, the tilt angle is adjusted so that the solar condensing spot is located at the center in the north-south direction of the solar cell (or the concentrator) at the time of south-south.

  In step S5, azimuth angle adjustment (adjustment of the azimuth axis offset Δω) is executed. Specifically, the azimuth angle is adjusted so that the solar condensing spot is positioned at the center in the east-west direction of the solar cell (or the concentrator) at the time in the south and middle. The processes in steps S4 and S5 are processes performed on one tracking gantry. For a plurality of tracking gantry, an azimuth angle and an inclination angle are set for each tracking gantry. The

  The true north-south direction and east-west direction can also be obtained by surveying. Based on the survey result, the tilt angle axis offset Δφ and the azimuth axis offset Δω can be adjusted. However, in the solar tracking device 1 according to the embodiment of the present invention, as described above, the solar tracking device 1 tracks the sun when the sun is coming out, and the solar tracking device 1 in the north-south direction based on the tracking result. And the structure which adjusts the east-west direction is preferable.

  In step S6, the sun tracking device 1 according to the embodiment of the present invention tracks the sun throughout the day, and measures the azimuth angle α0 and the inclination angle η0. Specifically, in the solar tracking device 1 according to the embodiment of the present invention, the tilt angle actual measuring means 414 (inclinometer (for example, liquid level inclinometer)) and the azimuth actual angle measuring means 415 (the direction meter (for example, GPS compass)). ). Then, the azimuth angle measuring means 414 and the inclination angle measuring means 415 measure the inclination angle η0 and the azimuth angle α0 throughout the day of the solar tracking device 1 according to the embodiment of the present invention. Then, the angle acquisition means accumulates the azimuth angle and inclination angle actually measured throughout the day as data.

  As a tracking error measurement method (azimuth angle measurement means 414 and tilt angle measurement means 415), a PSD (Position Sensitive Detector: optical position sensor) element is used to track the sun throughout the day and measure the tracking error. It may be a method (refer to Non-Patent Document 1 for a specific tracking error measurement method using a PSD element).

  In step S7, the position calculation formula setting means 412 fits the data accumulated in step S6 to a theoretical formula (model formula) to calculate correction parameters δx, δy, and δz.

  Specifically, a graph of the inclination angle η0 and the azimuth angle α0 can be created based on the measurement results of the inclinometer and the azimuth meter installed in the solar tracking device 1 throughout the day. If the sun tracking device 1 includes an installation error, a deviation occurs between this graph and the theoretical equation graph. The values of the correction parameters δx, δy, and δz are calculated by fitting this deviation by the least square method. In other words, the correction parameters δx, δy, and δz are determined (calculated) so that the actual inclination angle and azimuth angle graph and the inclination angle and azimuth angle graph of the theoretical formula match (or the difference is reduced). ) Then, the calculated correction parameters δx, δy, δz are replaced with initial values.

  In step S8, the correction parameter determination unit 411 determines whether the tracking error is within a predetermined value as a result of performing tracking calculation using the calculated correction parameters δx, δy, δz. . Specifically, for example, it is determined whether or not the error is within 0.05 °. When the error using the values of the correction parameters δx, δy, δz exceeds a predetermined value, the process returns to step S3, and the operations from step S3 to step S8 are repeated. If the correction parameters δx, δy, and δz vary under the influence of irregular measured values, the tilt angle axis offset Δφ and the azimuth axis offset Δω also vary, and these values must be readjusted. . For this reason, if the error using the values of the correction parameters δx, δy, δz exceeds a predetermined value, it is necessary to return to step S4.

  If the error using the values of the correction parameters δx, δy, δz is within a predetermined value, the correction parameter determination means 411 regards that the correction parameters have converged, and the solar tracking device 1 uses the sun tracking device 1 It is determined as a correction parameter used for tracking. This completes the adjustment. And the determined correction parameter is memorize | stored in the memory | storage means provided in the control apparatus 14 of the solar tracking apparatus 1. FIG. Thereafter, the position control means 41, the azimuth angle measurement means 414, and the tilt angle measurement means 415 mounted on the solar tracking device 1 may be detached from the solar tracking device 1. In other words, after the correction parameter is determined, the position control unit 41, the azimuth angle measurement unit 414, and the tilt angle measurement unit 415 are not necessary.

  If there is an installation error when installing the solar tracking device 1, a tracking error occurs in the solar tracking device 1. This tracking error changes from moment to moment, and may change depending on the season. The appearance of the error may be reversed over time. According to the correction method of the solar tracking device 1 according to the embodiment of the present invention, by calculating the correction parameters δx, δy, and δz, the directional cosine of the sun taking into account the error can be expressed as a function of time. become able to. Based on this time function, the sun can be tracked so that the tracking error is reduced. That is, correction can be performed in software so that the tracking error is reduced.

  Moreover, according to the correction method of the solar tracking device 1 according to the embodiment of the present invention, once the tracking error is measured using the azimuth meter and the inclinometer and the correction parameter is calculated, the calculated correction is performed thereafter. The error can be corrected based on a function of time including the parameters. Therefore, if the function of time including the correction parameter can be found, there is no need to constantly monitor the sun.

  Next, examples of the present invention will be described. FIGS. 6A and 6B are graphs showing the tracking error before correction and the tracking error after correction of the solar tracking device 1. This graph shows the results of a numerical experiment. The north-south angle of the azimuth axis tilt from the vertical direction, the east-west angle of the azimuth axis tilt from the vertical direction, and the tilt angle axis. The inclination from the horizontal direction is given as an installation error by random numbers. The circumferential direction indicates the direction of the sun as viewed from the solar cell, and the radial direction indicates the magnitude of the error. As a common condition of (a) and (b), the solar tracking device 1 is installed at a position of longitude: 34.884 ° and latitude of 136.826 °, and the tracking error is calculated throughout the day on the day of the summer solstice.

  In the graph shown in (a), the north-south angle (δδx) is 0.555 ° out of the inclination from the vertical direction of the azimuth axis, and the east-west direction is out of the inclination from the vertical direction of the azimuth axis. It is a graph in which the tracking error is calculated on the assumption that the angle (δδy) is 1.258 ° and the inclination of the inclination angle axis from the horizontal direction (δδz) is −1.847 °. (B) is that the north-south angle (δδx) of the tilt from the vertical direction of the azimuth axis is 0.732 °, and the east-west angle (δδy) of the tilt from the vertical direction of the azimuth axis is It is the graph which calculated tracking error on the assumption that there is an installation error of −1.551 ° and the inclination (δδz) of the inclination angle axis from the horizontal direction is −1.592 °.

  In the graph shown in (a), the tracking error before correction is widely distributed in a range of 1 to 5 °, the tracking error is a large value, and the error width is also large. On the other hand, the tracking error after correction is generally within 0.02 °. In the graph shown in (b), the tracking error before correction has a value larger than 1 °. On the other hand, the tracking error after correction is generally within 0.02 °. Thus, according to the correction method according to the embodiment of the present invention, the tracking error can be kept within 0.02 °.

  The embodiments and examples of the present invention have been described above. However, the present invention is not limited to the above-described embodiments or examples, and various modifications can be made without departing from the spirit of the invention. Needless to say.

BRIEF DESCRIPTION OF THE DRAWINGS It is the external appearance perspective view which showed typically the structure of the solar tracking apparatus 1 concerning embodiment of this invention, and a solar power generation device provided with this solar tracking apparatus 1. FIG. It is the figure which showed the celestial sphere coordinate system typically. It is the figure which showed the ground coordinate system typically. It is the figure which showed typically the shift | offset | difference of a logical ground coordinate system and the coordinate system of the solar tracking apparatus 1, and shows the definition of correction parameters (delta) x, (delta) y, and (delta) z. It is the flowchart which showed the procedure of the calculation method of a correction parameter. (A), (b) is the graph which showed the tracking error before correction of the solar tracking device 1, and the tracking error after correction, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solar tracking apparatus 11 Support | pillar 12 Horizontal rotation drive mechanism 13 Jack 131 Support shaft 14 Control apparatus 2 Power generation module 3 Base

Claims (2)

A solar tracking device for a concentrating solar power generation device that includes a power generation module that collects sunlight to generate power, the azimuth angle measuring means for measuring the azimuth angle α of the sun over time, and the inclination angle of the sun Inclination angle measurement means that measures η over time, and position control means that performs position control for directing the power generation module toward the direction of the sun, wherein the position control means is the direction of the sun indicated by an orthogonal coordinate system on the ground Position calculation formula setting means for setting the cosine (l, m, n) as the sum of the theoretical direction cosine (ll, mm, nn) and the date and time function taking the correction parameters (δx, δy, δz) into account; Angle acquisition means for acquiring an azimuth angle α1 and an inclination angle η1 that are actual measurement values from the azimuth angle measurement means and the tilt angle measurement means, the acquired azimuth angle α1 and inclination angle η1, and the sun direction cosine Total calculated from (l, m, n) A correction parameter determining means for determining the correction parameter (δx, δy, δz) as a constant by comparing the azimuth angle α0 with the inclination angle η0, and determining the correction parameter (δx, δy, δz); As the subsequent position control, the light is collected by tracking the sun using the calculation formula (1) of the azimuth angle α0 and the calculation formula (2) of the tilt angle η0 using the determined correction parameters (δx, δy, δz). Type solar power generator solar tracking device. Here, l and m in Equation (1) are expressed by Equation (3) and Equation (4), respectively. Ω is the hour angle, δ is the solar declination, and φ is the latitude at which the solar tracking device is installed.

A solar tracking device tracking method for a concentrating solar power generation device including a power generation module that collects sunlight to generate power, wherein the actual solar azimuth angle while the solar tracking device is exposed to the sun And measuring the tilt angle over time, storing the measured azimuth angle and tilt angle cumulatively, and the actual sun direction cosine (l, m, n) is set as the sum of the theoretical sun direction cosine (ll, mm, nn) and the date and time function taking the correction parameters (δx, δy, δz) into account, and the correction parameters (δx, δy, δz) and comparing the stored azimuth and tilt angles with the calculated azimuth and tilt angles calculated from the cosine (l, m, n) of the sun. Correction parameters (δx, δy, δz) are constants And the step of replacing the initialized correction parameters (δx, δy, δz) with the determined correction parameters (δx, δy, δz), and the correction parameters (δx determined and replaced as constants). , Δy, δz), and after storing the corrected parameters (δx, δy, δz) determined and replaced as constants, the azimuth angle α0 of the sun is expressed by Equation (5). A tracking method for a solar tracking device, characterized in that tracking is performed using the following equation (6). Here, l and m in Expression (5) are expressed by Expression (7) and Expression (8), respectively. Ω is the hour angle, δ is the solar declination, and φ is the latitude at which the solar tracking device is installed.

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