Control method for altitude angle variable solar generator

Abstract

The present invention relates to a control method for a photovoltaic power generation device. The control method for a photovoltaic power generation device with a variable elevation angle according to the present invention comprises: a photovoltaic panel part (10) composed of a photovoltaic cell (11) and a photovoltaic cell frame (12) that holds the photovoltaic cell; a support frame part (20) that allows the photovoltaic panel part (10) to be adjustable in height and allows the photovoltaic panel part (10) to be rotated at a predetermined height above the ground; a driven gear part (30) that is fixedly coupled to the photovoltaic panel part (10) and rotatably coupled to the support frame part (20) to rotate the photovoltaic panel part (10); and a driving gear part (40) that transmits rotational force to the driven gear part (30). A control method for an elevation angle variable photovoltaic power generation device comprising a motor unit (50) that applies rotational force to the drive gear unit (40) and a limit switch unit (60) installed on the support frame unit (20) to detect over-rotation of the driven gear unit (30), wherein when L is the length of the side perpendicular to the rotation axis of the photovoltaic panel unit (10), D is the distance between adjacent elevation angle variable photovoltaic power generation devices, Ψ is the elevation angle in the east-west direction of the sun, and θ is the angle that the photovoltaic panel unit (10) makes with the horizontal plane, a value in the range of 0 to 45° among the θ values ​​satisfying [Equation 1] below is determined as the maximum critical angle θMAX that the photovoltaic panel unit (10) can rotate, and the photovoltaic panel unit (10) is controlled within a range that satisfies the condition of [Equation 2] below with respect to the horizontal plane. [Mathematical Formula 1]

Description

Technology Field

[0001] The present invention relates to a control method for a photovoltaic power generation device, and more specifically, to a control method capable of changing the normal direction of a photovoltaic panel so as to track the sun, which changes according to the time of day. Background Technology

[0002] Due to various reasons, including environmental issues and the depletion of fossil resources, active technological development is underway regarding the production, distribution, and utilization of energy known as new and renewable energy. Among these, solar energy is currently receiving the most investment and installation due to its numerous advantages, such as the potential for infinite use as long as the sun exists (meaning continuous energy production is possible as long as the sun is present), ease of entry through the ability to install on a small scale compared to wind or hydropower, and its eco-friendliness as it does not generate polluting substances or phenomena during the production process. For example, it is common to see solar panels installed at highway rest areas, on building rooftops, and in ground-level parking lots, serving the dual purpose of providing shade.

[0003] To effectively produce solar energy—that is, to generate the highest power from the same amount of sunlight—sunlight must be directed nearly perpendicularly onto the solar panels. However, since the direction of the sun changes due to the Earth's rotation, the panels must be continuously made to track the sun to ensure that sunlight is consistently incident as perpendicularly as possible. In other words, the orientation of the solar panels must be controllable.

[0004] 'Patent Document 1' discloses a 'solar power generation device' capable of controlling the direction of such a solar panel, and FIG. 1 is a perspective view thereof. The conventional solar power generation device can control the direction of the solar panel (1) by including a vertical gear (3) connected to the rear of the solar panel (1) and a vertical gear drive motor (5) that is gear-coupled to the vertical gear (3) and moves the vertical gear (3).

[0005] For efficiency reasons, these solar power generation devices are often not installed individually, but rather multiple solar power generation devices are installed at spaced intervals over a large area, and inverters, power storage devices, control devices, etc. are shared to form a large-scale solar power generation system.

[0006] However, when multiple solar power generation devices are adjacent in this manner, as previously mentioned, if sunlight is incident on the solar panel (1) as close to vertical as possible, the adjacent solar power generation device prevents sunlight from reaching the solar panel of another solar power generation device. In other words, a shadow is created on the solar panel of another solar power generation device, which causes a problem in that the overall power generation of the solar power generation system decreases. This problem becomes more severe as the sun's altitude decreases, that is, as sunlight is incident closer to horizontal. Considering that one of the reasons for controlling the altitude angle in a solar power generation device is to maximize solar power generation immediately after sunrise and immediately before sunset, a method is needed to maximize solar power generation even when the sun's altitude is low. Prior art literature

[0008] KR 10-2009-0126157 A (2009. 12. 8.) The problem to be solved

[0009] The present invention has been devised to solve the above-mentioned problems, and the objective of the present invention is to provide a control method for a photovoltaic power generation device that can improve photovoltaic power generation efficiency when the sun's altitude is low, such as immediately after sunrise and immediately before sunset. means of solving the problem

[0010] A control method for an elevation angle variable photovoltaic power generation device according to the present invention comprises: a photovoltaic panel part composed of a photovoltaic cell and a photovoltaic frame that holds the same; a support frame part that allows the height of the photovoltaic panel part to be adjusted and enables the photovoltaic panel part to be rotated at a predetermined height above the ground; a driven gear part that is fixedly coupled to the photovoltaic panel part and rotatably coupled to the support frame part to rotate the photovoltaic panel part; and a driving gear part that transmits rotational force to the driven gear part (30). A control method for an elevation angle variable photovoltaic power generation device comprising a motor unit that applies rotational force to the drive gear unit and a limit switch unit installed on the support frame unit that detects over-rotation of the driven gear unit, wherein L is the length of the side perpendicular to the rotation axis of the photovoltaic panel unit, D is the distance between adjacent elevation angle variable photovoltaic power generation devices, Ψ is the elevation angle in the east-west direction of the sun, and θ is the angle that the photovoltaic panel unit (10) makes with the horizontal plane, wherein a value in the range of 0 to 45° among the θ values ​​satisfying [Equation 1] below is the maximum critical angle θ at which the photovoltaic panel unit (10) can rotate. MAX The technical feature is to determine that the solar panel part is controlled within a range that satisfies the horizontal plane and the condition of [Equation 2] below.

[0011] [Mathematical Formula 1]

[0012] [Mathematical Formula 2] Effects of the invention

[0013] The control method of the elevation angle variable photovoltaic power generation device according to the present invention improves power generation efficiency when the sun's altitude is low, thereby increasing the overall amount of power generated.

[0014] In addition, since the instantaneous power immediately after sunrise or just before sunset is higher than in the past, the operating time of battery-free systems can be extended. Brief explanation of the drawing

[0016] FIG. 1 is a perspective view of a conventional solar tracking device. FIG. 2 is a perspective view of an elevation angle variable photovoltaic power generation device that is the subject of the present invention. FIG. 3 is an exploded perspective view of the main parts of an elevation angle variable photovoltaic power generation device that is the subject of the present invention. Figure 4 is a photograph of an arc-shaped gear without a frame in the secant section. FIG. 5 is an enlarged view of the part where the driving gear and the driven gear mesh. FIG. 6 is a diagram showing the usage state of an elevation angle variable photovoltaic power generation device according to the present invention. Figure 7 is a diagram showing the relationship between two adjacent elevation-angle variable photovoltaic power generation devices and the sun. Figure 8 shows the sun's azimuth and elevation angles in a spherical coordinate system. Specific details for implementing the invention

[0017] Hereinafter, a control method for an elevation angle variable photovoltaic power generation device according to the present invention will be described in detail with reference to the attached drawings.

[0019] To aid understanding, the elevation angle variable photovoltaic power generation device that is the subject of the control method according to the present invention will be described first.

[0021] FIG. 2 is a perspective view of an elevation angle variable photovoltaic power generation device that is the subject of the present invention, and FIG. 3 is an exploded perspective view of a main part such as a driven gear part and a driving gear part. The elevation angle variable photovoltaic power generation device is composed of a photovoltaic panel part (10), a support frame part (20), a driven gear part (30), a driving gear part (40), a motor part (50), and a limit switch part (60).

[0023] The solar panel section (10) is composed of a solar cell (11) and a solar cell frame (12) that holds the solar cell.

[0025] The support frame section (20) is a component that allows the height of the solar panel section (10) to be adjusted and enables the solar panel section (10) to rotate at a predetermined height above the ground, and is composed of a base plate (21), a holder (22) vertically coupled to the base plate, a vertical frame (23) inserted into the holder (22), a bolt (B) that passes through the holder (22) and is fastened to the vertical frame (23), a horizontal frame (24) connecting a plurality of vertical frames (23), a hinge (25) installed on the horizontal frame (24) to enable the solar panel section (10) to rotate, and a support member (26) through which the drive shaft (42) of the drive gear section (40) passes.

[0027] The driven gear unit (30) is a component that is fixedly coupled to the solar panel unit (10) and rotatably coupled to the support frame unit (20) to rotate the solar panel unit (10) by the rotation of the driving gear unit (40). The driven gear unit (30) is composed of an arc-shaped gear (31) that is meshed with the driving gear unit (40), a connecting frame (32) with one end coupled to the solar cell frame (12) of the solar panel unit (10) and the other end abutting the arc-shaped gear (31), and a connecting frame (33) that connects the arc-shaped gear (31) and the other end of the connecting frame (32).

[0028] The arc-shaped gear (31) is a gear with a shape close to a semicircle, consisting of an arc and a secant line, formed by cutting a part of a circle with a straight line. A tooth (31-1) may be formed on the outer side facing the driving gear part (40). The secant line portion connecting the ends of the arc is formed as a reinforcing frame (31-2) to prevent deformation of the arc-shaped gear (31).

[0029] The reason for connecting the secting portion of the arc gear (31) to the reinforcing frame (31-2) is related to the manufacturing method of the arc gear (31). Although gears can be manufactured by cutting, grinding, or casting, the manufacturing time and cost are significantly higher than those of laser processing (3 to 6 times). Therefore, considering ease of processing and cost, it is common to manufacture the arc gear (31) by laser processing a thick steel plate. However, in the case of laser processing, when forming teeth along the arc, as time passes from the first tooth processing to the final tooth processing, the steel plate is heated and expanded during processing. Consequently, after it reaches room temperature, the steel plate shrinks, and the gear shape with the originally planned curvature is not formed. FIG. 4 is a photograph of the arc gear initially manufactured by the inventor while inventing the present invention, in which there is no frame in the secting portion. The line R in Fig. 4 is a circle drawn from the center of rotation of the gear, and it can be seen that as one side (upward) of the arc-shaped gear moves, the teeth move further away from the center of the circle, and in this case, it can be seen that the gear engagement with the driving gear part (40) is not smooth.

[0030] In order to solve this problem, the arc-shaped gear (31) of the present invention has the secant section left as a reinforcing frame (31-2), and in this structure, the shape of the arc-shaped gear (31) can be made to almost match the planned curvature {so that the gear engagement with the driving gear part (40) is maintained smoothly}.

[0031] The toothed portion (31-1) of the arc gear (31) and the middle portion of the reinforcing frame (31-2) can be connected to an auxiliary frame (31-3). The auxiliary frame (31-3) serves to mechanically increase the strength of the arc gear (31) and can also serve as an installation guide in relation to the connecting frame (32).

[0032] The connecting frame (32) is a component that connects the solar panel section (10) and the arc gear (31), and is composed of two outer connecting frames (32-1) with one end contacting both ends of the arc gear (31) and the other end connected to the solar panel section (10), and may further include an inner connecting frame (32-2) with one end connected to the auxiliary frame (31-3) of the arc gear (31) and the other end connected to the solar panel section (10). When the inner connecting frame (32-2) is present, it is preferable that the inner connecting frame (32-2) and the auxiliary frame (31-3) have the same width. This is because when assembling the elevation angle variable solar power generation device and the control method thereof according to the present invention, the worker can easily determine the position of the arc gear (31) when the solar panel section (10) is horizontal by aligning the inner connecting frame (32-2) and the auxiliary frame (31-3). That is, the positional relationship between the solar panel section (10) and the arc gear (31) can be accurately implemented as designed by the inner connecting frame (32-2) and the auxiliary frame (31-3).

[0033] The connecting frame (33) is a component that connects the arc-shaped gear (31) and the outer connecting frame (32-1), and also serves as a safety device. Since the safety device function is activated when the limit switch unit (60) fails or when an accident occurs that exceeds the driving constraints of the limit switch unit (60), it will be mentioned again after explaining the limit switch unit (60).

[0035] The driving gear unit (40) is a component that transmits rotational force to the driven gear unit (30), and FIG. 5 is an enlarged view of the part where the driving gear unit (40) and the driven gear unit (30) mesh. The driving gear unit (40) is composed of a driving gear (41) that meshes with an arc-shaped gear (31), a driving shaft (42) that passes through the driving gear (41), a pair of clamps (43) that grip the driving shaft (42) from the outside of the driving gear (41), and a bolt (B) that fastens the clamps (43) and the driving gear (41), and a detachment prevention plate (44) may be further provided between the driving gear (41) and the clamps (43).

[0036] The drive gear (41) is a general circular gear, and a bolt hole (H) is formed that penetrates the gear surface.

[0037] The drive shaft (42) is a component that transmits the rotational force of the motor unit (50) to the drive gear (41), and is not directly connected to the drive gear (41) by welding or the like, but is connected to the drive gear (41) by a clamp (43) and a bolt (B).

[0038] A pair of clamps (43) are components that connect the drive gear (41) and the drive shaft (42). A groove identical to the curvature of the drive shaft (42) is formed on the opposing inner surface of the pair of clamps (43), and the pair of clamps (43) are fastened by a bolt (B) to make surface contact with the drive shaft (42) and are fixed to the drive shaft (42). Therefore, the cross-sectional area of ​​the hollow formed when the pair of clamps (43) are facing each other must be smaller than the cross-sectional area of ​​the drive shaft (42). The reason why clamping is used instead of direct connection such as welding as a means of connecting the drive gear (41) and the drive shaft (42) in the present invention is that in the case of direct connection, it is difficult to separate the drive gear, etc. in the event of a malfunction or incorrect assembly, and the connecting force due to the surface contact between the clamp (43) and the drive shaft (42) is not lower than that of welding.

[0039] A bolt hole (H) is also formed in the clamp (43), and the drive gear (41) and the drive shaft (42) are connected by fastening the bolt hole (H) of the drive gear (41) and the bolt hole (H) of the clamp (43) with a bolt (B).

[0040] The anti-detachment plate (44) is a circular plate with a radius larger than that of the driving gear (41) and is located on the outside of the driving gear (41). Thus, the anti-detachment plate (44) covers the tooth (31-1) portion of the arc gear (31), so that the arc gear (31) does not detach from the outside of the driving gear (41). Since the driven gear portion (30) and the driving gear portion (40) are provided on both sides of the solar panel portion (10), two anti-detachment plates (44) are provided, and thus the two anti-detachment plates (44) restrict the outer edges of the arc gears (31) on both sides, so that in the present invention, the arc gear (31) does not detach from the driving gear (41).

[0042] The motor unit (50) is a component that applies rotational force to the drive gear unit (40) by rotating the drive shaft (42), and it is preferable for it to be located in the center of the elevation angle variable solar power generation device and the control method thereof according to the present invention. This is because, in the present invention, the driven gear unit (30) is provided at least at both ends of the solar panel unit (10), and for this to be possible, the drive gear (41) must also be provided at both ends of the solar panel unit (10), and in order to ensure that the same force is transmitted to both arc gears (31) and the drive gear (41), it is better for the motor unit (50) to be located in the center rather than concentrated on one side. For reference, depending on the size of the solar panel unit (10), one or more driven gear units (30) and drive gears (41) may be provided in the middle in addition to both ends of the solar panel unit (10).

[0044] The limit switch unit (60) is a component installed on the vertical frame (23) of the support frame unit (20) to detect over-rotation of the driven gear unit (30), more specifically, the arc gear (31). That is, when a trigger provided at the rotation limit point of the arc gear (31) touches the lever (61) of the limit switch unit (60), the operation of the motor unit (50) is stopped, thereby allowing the solar panel unit (10) to operate within the rotation limit. In this case, one of the bolts (TB, trigger-bolt) connecting the arc gear (31) and the coupling frame (33) that connects the arc gear (31) and the outer connecting frame (32-1) without forming a separate protrusion can be used as the trigger. This is because, since the coupling frame (33) is provided at the outermost edge of the tooth (31-1) of the arc gear (31), it must be made impossible to rotate beyond that point.

[0046] The elevation angle variable solar power generation device can provide two safety effects with a single coupling frame (33). The first is to act as a trigger for the limit switch unit (60) described above, and the second is due to the arc-shaped groove (33-1) formed in the coupling frame (33). Since the trigger bolt (TB) of the coupling frame (33) is connected to the arc-shaped gear (31) and the arc-shaped groove (33-1) is formed outside the trigger bolt (TB), even if the driving gear (41) over-rotates the arc-shaped gear (31) due to a failure or malfunction of the limit switch unit (60), slip occurs in the arc-shaped groove (33-1), preventing the driven gear unit (30) from rotating further. Consequently, the electronic safety means provided by the limit switch unit (60) and the mechanical safety means provided by the arc-shaped groove (33-1) operate in a dual manner. The radius of curvature of the arc-shaped groove (33-1) should not be smaller than (greater than or equal to) the radius of curvature of the drive gear (41), and preferably, the radius of curvature of the arc-shaped groove (33-1) and the drive gear (41) should be the same so that the drive gear (41) can be idled while seated in the arc-shaped groove (33-1).

[0048] FIG. 6 is a diagram showing the usage state of an elevation angle variable solar power generation device, illustrating the device being driven from the side. As can be seen in FIG. 6(a) to (c), the elevation angle variable solar power generation device can follow the sun in the direction of the azimuth or elevation angle. FIG. 6(c) illustrates a state in which the angle change of the solar panel part (10) is limited by the trigger bolt (TB) triggering the limit switch part (60). Even if the solar panel part (10) rotates beyond this state, the drive gear (41) slips in the arc groove (33-1) and the solar panel part (10) no longer rotates.

[0049] FIG. 6(b) illustrates a structure in which the solar panel section (10) is horizontally aligned with the aforementioned inner connecting frame (32-2) and auxiliary frame (31-3). In this state, the driving gear (41) must be positioned at the center of the teeth (31-1) of the arc-shaped gear (31) so that the maximum rotation angle of the solar panel section (10) is equal on both the left and right sides according to the drawing (considering the case where it rotates in the azimuth direction following the sun). Therefore, the reinforcing frame (31-2) of the arc-shaped gear (31) is tilted from the horizontal, and the solar panel section (10) and the reinforcing frame (31-2) are not parallel.

[0050] This relates to a structure in which the driving shaft (42) is not placed vertically below the solar panel section (10), but rather a support member (26) is provided on the side of the vertical frame (23) of the support frame section (20), and the driving shaft (42) is supported by passing through the support member (26). If the driving shaft (42) were to be placed vertically below the solar panel section (10), the driving shaft (42) would have to be installed to pass through the vertical frame (23) of the support frame section (20). However, this would make manufacturing difficult and lower the rigidity of the vertical frame (23), thereby impairing the stability of supporting the solar panel section (10). Therefore, to avoid this problem, the driving shaft (42) is provided on the side of the vertical frame (23), and when the solar panel section (10) is horizontal, the driving gear (41) is geared at the center of the tooth (31-1) of the arc-shaped gear (31).

[0052] Next, a control method for an elevation angle variable photovoltaic power generation device according to the present invention will be described. Briefly, the core of the control method for an elevation angle variable photovoltaic power generation device according to the present invention is to prevent shading from occurring on the solar panel section (10) of an adjacent solar power generation device by the solar panel section (10) of a specific solar power generation device in a photovoltaic power generation system equipped with a plurality of elevation angle variable photovoltaic power generation devices. Since the present invention is particularly intended to improve solar power generation efficiency immediately after sunrise and immediately before sunset, it is assumed that the rotation axis of the solar panel section (10) of the elevation angle variable photovoltaic power generation device is in the north-south direction. That is, it is assumed that the normal direction of the solar panel section (10) can change from east to west and from west to east.

[0054] FIG. 7 is a diagram showing the relationship between two adjacent variable elevation angle solar power generation devices and the sun. In the present invention, the condition for not having a shade on the solar panel section (10) between adjacent variable elevation angle solar power generation devices can be derived as shown in [Equation 1] below, where L is the length of the side perpendicular to the rotation axis {hinge (25)} of the solar panel section (10), D is the distance between adjacent variable elevation angle solar power generation devices, Ψ is the east-west elevation angle of the sun (the elevation angle of the east-west component among the azimuth and elevation angles at which sunlight is irradiated as the sun moves. This will be explained again below), and θ is the angle that the solar panel section (10) makes with the horizontal plane (ground).

[0055]

[0057] After a plurality of elevation-angle variable photovoltaic power generation devices according to the present invention are installed, L and D are determined and are fixed values, and since Ψ is given by the position of the sun, the θ value satisfying [Equation 1] above can be known. Among the θ values, the value in the range of 0 to 45° is the maximum critical angle θ at which the photovoltaic panel part (10) can rotate. MAX By determining this and controlling the solar panel section (10) within a range that satisfies the horizontal plane and the conditions of [Equation 2] below, the solar power generation efficiency can be improved. For reference, among the θ values ​​satisfying [Equation 1] above, a value of 45° or less is θ MAX The reason for deciding as θ MAX , 90°- θ MAX , 180°+ θ MAX , 270°- θ MAX This is because there are infinitely many general solutions.

[0058]

[0060] The above explanation was based on the sun's east-west elevation angle Ψ, but control conditions can be derived by changing this to the sun's azimuth and elevation angles.

[0061] Figure 8 illustrates the azimuth and elevation angles of the sun in a spherical coordinate system, where the azimuth angle Φ increases as the sun moves in the south and west directions with east as 0°, and the elevation angle Ω increases as the sun moves in the zenith (90°) direction relative to the horizontal plane. The sun's direction vector with respect to the origin is (cosΩsinΦ, cosΩcosΦ, sinΩ), and the east-west elevation angle is related to the second and third components of the upward direction vector as shown in [Equation 3] below.

[0062]

[0064] Substituting [Equation 3] into [Equation 1] yields [Equation 4] below, and among the θ values ​​satisfying [Equation 4], the value in the range of 0 to 45° is the maximum critical angle θ at which the solar panel part (10) can rotate. MAX After determining this, if it is controlled within a range that satisfies the conditions of [Equation 2] above, it becomes possible to control the rotation angle of the solar panel part (10) based on the direction of the sun.

[0065] Explanation of the symbols

[0067] 10 Solar panel section 11 Solar cell 12 Solar cell frame 20 Support frame section 21 Base plate 22 Holder 23 Vertical frame 24 Horizontal frame 25 Hinge 26 Support 30 Driven gear section 31 Arc-type gear 31-1 Cog 31-2 Reinforcement Frame 32 Connecting Frame 32-1 Outer Connecting Frame 32-2 Inner connecting frame 33 Joining frame 33-1 Arc-shaped groove 40 Drive gear section 41 Drive gear 42 Drive shaft 43 Clamp 44 Anti-detachment plate 50 Motor section 60 Limit switch 61 lever B bolt H bolt hole

Claims

Claim 1 A control method for an elevation angle variable photovoltaic power generation device comprising: a solar panel section (10) composed of a solar cell (11) and a solar cell frame (12) that holds the same; a support frame section (20) that allows the height of the solar panel section (10) to be adjustable and enables the solar panel section (10) to rotate at a predetermined height above the ground; a driven gear section (30) that is fixedly coupled to the solar panel section (10) and rotatably coupled to the support frame section (20) to rotate the solar panel section (10); a driving gear section (40) that transmits rotational force to the driven gear section (30); a motor section (50) that applies rotational force to the driving gear section (40); and a limit switch section (60) installed on the support frame section (20) to detect over-rotation of the driven gear section (30), wherein the rotation axis of the solar panel section (10) is in the north-south direction, the length of the side perpendicular to the rotation axis of the solar panel section (10) is L, and the adjacent elevation angle When D is the distance between variable photovoltaic power generation devices, Ψ is the elevation angle of the sun in the east-west direction, and θ is the angle that the photovoltaic panel part (10) makes with the horizontal plane, the value of θ in the range of 0 to 45° among the θ values ​​satisfying [Equation 1] below is the maximum critical angle θ at which the photovoltaic panel part (10) can rotate. MAX A control method for an elevation angle variable photovoltaic power generation device characterized by determining the angle θ that the photovoltaic panel part (10) makes with the horizontal plane and controlling the angle θ within a range satisfying the condition of [Equation 2] below, so that the normal direction of the photovoltaic panel part (10) can continuously change from east to west. [Equation 1] [Mathematical Formula 2] Claim 2 In claim 1, when the azimuth angle of the sun is Φ and the elevation angle is Ω, the value of θ satisfying [Equation 4] below in the range of 0 to 45° is the maximum critical angle θ at which the solar panel part (10) can rotate. MAX A control method for an elevation angle variable photovoltaic power generation device characterized by determining [Equation 4].

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