Tracking device for tracking a beam path of a photovoltaic lens unit depending on the sun position

Abstract

The invention relates to a tracking device (10) for tracking a beam path (S) of a photovoltaic lens unit (110) depending on the sun position, comprising a first tracking frame (20) with a plurality of first mirror elements (22) moveably mounted therein and a second tracking frame (40) with a plurality of second mirror elements (42) moveably mounted therein and arranged after the first mirror elements (22) in the beam path (S), and comprising a first control device (24) with a first control actuator (25) for moving the first mirror elements (22) about first control axes (23) between at least two different angular positions and a second control device (44) with a second control actuator (45) for moving the second mirror elements (42) about second control axes (43) between at least two different angular positions, wherein the orientation of the first control axes (23) differs from the orientation of the second control axes (43).

Description

[0001] Tracking device for tracking a beam path of a photovoltaic lens unit depending on the position of the sun

[0002] The present invention relates to a tracking device for tracking a beam path of a photovoltaic lens unit depending on the position of the sun, a photovoltaic module with such a tracking device and a tracking method for implementation on such a tracking device.

[0003] It is well known that in attempts to increase the efficiency of electricity production using photovoltaic cells, so-called multilayer photovoltaic cells are used. Each individual layer of such multilayer photovoltaic cells can produce electrical current from different wavelength ranges of solar radiation. Due to the multilayer arrangement with partially transparent layers, a higher efficiency can be achieved for such a multilayer photovoltaic cell on the same surface area compared to single-layer versions. However, such multilayer photovoltaic cells are very complex and therefore expensive in terms of the materials used and, in particular, their complexity.In order to take these high costs into account, such multi-layer photovoltaic cells are often built with smaller dimensions than classic photovoltaic cells and then the incoming solar rays are bundled onto this smaller photovoltaic cell with the help of a lens device.

[0004] A disadvantage of existing solutions, however, is that focusing with the help of a lens depends on the angle of incidence of the incoming sunlight. If the angle of incidence changes, the focal point also changes, meaning that this lens focusing does not function as desired throughout the entire course of the sun throughout the day. Existing solutions therefore track the entire photovoltaic lens unit to the current position of the sun using mechanical and motorized means. However, this requires a very high construction effort, as a large tracking module must be equipped with correspondingly large drive units and positioned precisely aligned with the current position of the sun.

[0005] The object of the present invention is to at least partially remedy the disadvantages described above. In particular, the object of the present invention is to reduce the space requirements and costs of tracking the position of the sun in a cost-effective and simple manner.

[0006] The above object is achieved by a tracking device having the features of claim 1, a photovoltaic module having the features of claim 16, and a tracking method having the features of claim 18. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the tracking device according to the invention naturally also apply in connection with the photovoltaic module according to the invention and the tracking method according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0007] According to the invention, a tracking device is proposed for tracking a beam path of a photovoltaic lens unit depending on the position of the sun. Such a tracking device has a first tracking frame with a plurality of first mirror elements movably mounted therein. Furthermore, a second tracking frame is provided with a plurality of second mirror elements movably mounted therein in the beam path after the first mirror elements. In addition, the tracking device has a first adjusting device with a first adjusting actuator for moving the first mirror elements about first adjusting axes between at least two different angular positions. Furthermore, a second adjusting device with a second adjusting actuator is provided for moving the second mirror elements about second adjusting axes between at least two different angular positions.The alignment of the first adjustment axes and the alignment of the second adjustment axes differ from each other.

[0008] A tracking device according to the invention thus serves to adjust the focus of a photovoltaic lens unit such that, even when the position of the sun changes, the lens's focus remains on the reduced-size multilayer photovoltaic cell. Such a tracking device can thus be used to equip a static arrangement of a photovoltaic lens unit with a tracked focusing function. This is ensured by the fact that multi-axis tracking can take place, which correlates with a static lens and a static photovoltaic cell. The multi-axis tracking is distributed between the two tracking frames arranged one behind the other in the beam path.

[0009] Each tracking frame has a plurality of mirror elements. The mirror elements serve to capture and deflect incoming sunlight depending on the angular position of the mirror surface. In other words, the angular position and thus the reflection direction of the mirror elements can be changed by the respective actuator of the respective adjusting device. Preferably, all mirror elements of each tracking frame are aligned parallel to one another so that for each tracking frame exactly one angular position and thus exactly one deflection direction for all mirror elements can be adapted to the current position of the sun. If, for example, the position of the sun sinks at a certain time of day, the mirror elements of the respective tracking frame relevant for the sinking and rising of the sun's position can be adjusted by changing the angular position.By changing the angle of incidence of the setting sun, the deflection is directed onto the lens in such a way that the lens continues to enable the desired focusing function on the photovoltaic cell. The additional tracking frame can have a different alignment axis, so that the correspondingly differently aligned adjustment axes result in tracking, for example, in an east-west direction. For this purpose, the incoming sun can now also be tracked in a movement from east to west over the course of the day. In the same way, by changing the angular position of the associated mirror elements, the irradiation on the lens of the photovoltaic lens unit can be maintained, thus achieving the tracked focusing.

[0010] As can be seen from the above explanation, multi-axis tracking can now be achieved by combining tracking frames arranged one after the other in the beam path. In particular, for example, the first tracking frame can serve a north-south tracking system, and the second tracking frame can serve an east-west tracking system. The combination of these two tracking systems, which can also be referred to as dual-axis or multi-axis tracking, allows for tracking of all possible solar radiation angles throughout the day and throughout the year, so that the lens can always, or essentially always, provide its focusing functionality on the reduced-size photovoltaic cell.

[0011] In contrast to known solutions, however, the tracking device according to the invention does not track the entire photovoltaic lens unit. Rather, it only adjusts the angular position of the individual mirror elements. In contrast to previous solutions with complex mechanics and motors, which had to move the entire photovoltaic lens unit, the embodiment according to the invention can manage with significantly smaller, lighter, and thus more cost-effective adjusting devices. The space requirement is also reduced, since the tracking functionality integrated into a static photovoltaic lens unit allows several photovoltaic lens units to be arranged directly next to one another. The high space requirements of the known mechanical tracking are no longer necessary here.

[0012] In addition to reducing the required installation space and the closer arrangement of several photovoltaic modules next to one another, the costs for manufacturing and installing such tracking devices are also reduced, as the absolute values ​​for the tracking movements are significantly reduced. Last but not least, it also becomes possible to perform significantly finer adjustments of the individual tracking movements, so that, for example, even each individual mirror element can be given its own angle specific to its exact position. Overall, the more precise tracking and more precise adjustment thus further improve the functionality of the tracking system and thus indirectly increase the efficiency across the entire solar trajectory using such a tracking device.

[0013] It can be advantageous if, in a tracking device according to the invention, each first mirror element has its own first adjustment axis and each second mirror element has its own second adjustment axis. The first adjustment axes are aligned parallel to one another and / or the second adjustment axes are also aligned parallel to one another. Mirror elements, each with its own adjustment axis, can each assume different angular positions.

[0014] If all mirror elements of a tracking frame are equipped with adjustment axes that are aligned parallel to one another, these are arranged in the adjustment plane explained later. The parallel arrangement of the adjustment axes makes it even easier to control the tracking movement and, in particular, to predefine adjustment specifications and thus target positions for the angular position of the adjustment elements. If this applies to parallel aligned adjustment axes of all mirror elements of all tracking frames, this can enable easier adjustment for the entire tracking movement. In principle, however, it is also possible to set a single, specific adjustment axis with a different and therefore specific angular position for each individual mirror element.

[0015] It may also be advantageous if, in a tracking device according to the invention, the first adjustment axes span a first adjustment plane and / or the second adjustment axes span a second adjustment plane. In particular, the first adjustment plane is aligned parallel or substantially parallel to the second adjustment plane and / or to a lens plane of the photovoltaic lens unit. A preferred embodiment has a mutually parallel design of the first adjustment plane, the second adjustment plane, and the lens plane. This parallel design can also be referred to as a sandwich construction and leads, among other things, to a very flat and compact construction.Last but not least, the parallel design of the individual adjustment planes to each other and to the lens plane also simplifies the tracking functionality, since a simplified geometric relationship between the adjustment planes, the adjustment axes, the mirror elements and their angular positions relative to the optical focusing function of the lens is output.

[0016] Furthermore, it is advantageous if, in a tracking device according to the invention, the first mirror elements are designed to be rotatable about the first adjustment axes and / or the second mirror elements are designed to be rotatable about the second adjustment axes. While any form of movement functionality is fundamentally possible as an adjustment movement, a rotational movement as an adjustment movement is advantageous in many respects. Among other things, a rotational movement serves to minimize the necessary free space as a range of motion. Because different angular positions are to be assumed, the rotational movement can also be controlled more easily because a rotational position directly correlates with the associated desired target angular position. Last but not least, a rotational movement about the adjustment axes also allows a further reduction in the overall height and thus facilitates the particularly flat design of a tracking device according to the invention.

[0017] A further advantage can be achieved if, in a tracking device according to the invention, the first actuating actuator and / or the second actuating actuator is designed for a translational actuating movement, in particular along an actuating direction transverse to the respective first actuating axes and the respective second actuating axes. A translational actuating movement likewise allows very simple controllability and, in particular, a flat design laterally to the respective actuating axes. As explained later, a single actuating actuator with a single actuating movement can then interact with a plurality of actuating axes of the plurality of respective mirror elements via a deflection mechanism. The actuating direction can therefore provide a pushing movement and a pulling movement transverse to the respective actuating axes as the actuating movement.If the individual adjustment axes are each located in an adjustment plane, the adjustment movement and thus the adjustment direction also extends parallel, preferably in one of these adjustment planes.

[0018] It is further advantageous if, in a tracking device according to the invention, the first mirror elements and / or the second mirror elements have a flat or substantially flat extension. While curved mirror elements or concave configurations are also conceivable in principle, straight and thus flat mirror elements can be used particularly simply and cost-effectively. A flat configuration is particularly advantageous and reduces complexity, particularly when using the partial mirrors explained later.

[0019] It is also advantageous if, in a tracking device according to the invention, the first mirror elements and / or the second mirror elements each have at least two partial mirrors which are mounted so as to be movable relative to one another in order to change the mirror surface of the respective first mirror element and / or second mirror element. The relative movement to one another can in particular ensure a telescopic displacement of the individual partial mirrors relative to one another, so that the degree of overlap of the partial mirrors can be changed. If the degree of overlap of the partial mirrors is reduced, this leads to an enlargement of the mirror surface of the respective mirror element and vice versa. If these partial mirrors are provided for all mirror elements, the mirror surface can also be varied depending on the angular position as an additional degree of freedom.Preferably, this also occurs through mechanical interaction via the respective actuator, so that, for example, the variation in height direction, angular position, and mirror surface (explained later) can be changed together with a single adjustment movement. Varying the mirror surface offers particular advantages in that, at certain angles of incidence of the sun's rays, areas would otherwise arise in which the incoming sunlight would not encounter any mirror element for deflection. In other words, such penetrating sunlight would evade deflection and thus not utilize the lens's focusing function as desired.By enlarging the mirror surface in precisely such angular positions, the proportion of sunlight passing through is reduced and thus the efficiency of the lens and thus the electrical efficiency of the photovoltaic lens unit is further improved even for such particularly flat angles of incidence and corresponding positions of the sun.

[0020] Of course, more than two partial mirrors can be provided for the mirror elements. This allows an even wider range of angles of incidence to be covered. The three or more partial mirrors preferably also form a telescopic movement function to ensure the same change in the mirror surface.

[0021] A further advantage can be achieved if, in a tracking device according to the invention, the first actuating actuator and / or the second actuating actuator is mounted so as to be movable in a vertical direction in order to change the vertical extent of the first tracking frame and / or the second tracking frame when carrying out the actuating movement for changing the mirror surface of the first mirror elements and / or the second mirror elements. This is achieved in particular by changing the overlap of the partial mirrors, as explained in the previous paragraph. For the change in the vertical direction, for example, an additional linear guide can be provided which can vary the distance between two partial frames. In this way, it is possible, for example with the aid of a laterally arranged slotted guide for at least one of these partial frames, to redirect the actuating movement in the actuating direction into an additional height adjustment in the vertical direction.In other words, a simple one-dimensional positioning movement of a positioning actuator is transformed into a multi-dimensional positioning and height variation, so that the height variation complements the positioning movement in the height direction, so to speak.

[0022] A further advantage can be achieved if, in a tracking device according to the invention, the first actuating actuator and / or the second actuating actuator interact directly or indirectly with a slotted guide for movement along the height direction. This slotted guide can, for example, be a guide opening in the form of an elongated hole or a more complex guide slot. For example, a U-shaped slotted guide can be provided. In particular, such a slotted guide is arranged on both sides of the respective tracking frame. The respective slotted guide converts the actuating movement, which is carried out in particular one-dimensionally along a actuating direction, at least partially into the height direction and thus supplements the actuating movement in the height direction to form a multi-dimensional actuating functionality.

[0023] It is also advantageous if, in a tracking device according to the invention, the first tracking frame and / or the second tracking frame each have a lower sub-frame and an upper sub-frame, wherein the first mirror elements and / or the second mirror elements are movably mounted in each of the two sub-frames. Thus, the mirror elements can each have two physical bearing adjustment axes, which deviate from their real adjustment axis with regard to angular positioning. Preferably, the mirror elements are rotatably mounted in each of the sub-frames. In particular, in combination with the variation in the height direction as explained in the preceding paragraphs, this brings advantages of a multi-dimensional adjustment movement.

[0024] It is furthermore advantageous if, in a tracking device according to the invention, the first tracking frame and / or the second tracking frame are identical or essentially identical. This applies in particular with regard to the type and manner of arrangement of the mirror elements, the size and design of the mirror elements, the movement options and / or the actuators of the adjusting devices and in particular the arrangement of the adjusting axes relative to one another. The tracking frames are preferably rotated by 90 degrees with regard to their adjusting functionality so that, when arranged in a photovoltaic module, they can each serve for north-south tracking and east-west tracking. It is a further advantage if, in a tracking device according to the invention, the first tracking frame and the second tracking frame are arranged one behind the other in the beam path, in particular overlapping completely or essentially completely.As already explained above with regard to the sandwich construction, a completely congruent overlap can further reduce the overall dimensions and thus minimize the required installation space. Because this allows for a very compact arrangement, several tracking devices can also be positioned next to each other in a directly adjacent manner.

[0025] It is also advantageous if, in a tracking device according to the invention, the first mirror elements and / or the second mirror elements have mirror foils at least in sections. While solid materials can in principle also be used as mirror elements, the use of mirror foils is considerably simpler and more cost-effective. Such mirror foils can, for example, be clamped in mirror frames of the individual mirror elements, wherein the desired tension on the mirror foils can be maintained with the aid of spring elements. In addition to the cost-effective design of the mirror foils, the distance between partial mirrors with mirror foils can be reduced in this way, so that despite the variation in the overlapping areas of such partial mirrors, a very small gap distance between these partial mirrors in the form of the mirror foils can be maintained.The advantages of changing the mirror surface can be further optimized with such an embodiment.

[0026] It is also advantageous if, in a tracking device according to the invention, a transparent protective cover is arranged in the beam path in front of the first tracking frame to protect against mechanical damage and / or contamination. This can be a plastic cover or a glass cover, for example. This serves to be transparent, in particular with regard to the wavelengths to be used in the multilayer photovoltaic cell. The side surfaces of the tracking devices can also be provided with a protective cover, although this does not necessarily have to be transparent. It is also advantageous if, in a tracking device according to the invention, the first tracking frame and / or the second tracking frame has an outer contour that is geometrically similar to the outer contour of the lens and / or the photovoltaic cell of the photovoltaic lens unit.In particular, this outer contour is similar to, but proportionally larger than, the outer contour of the photovoltaic cell. It is preferred if the tracking frames overlap and completely cover the outer contour of the lens, thus providing the tracking function according to the invention for the entire incident surface of the lens.

[0027] The present invention also relates to a photovoltaic module for generating electrical power. Such a photovoltaic module has at least one photovoltaic lens unit with a multilayer photovoltaic cell. A lens for focusing the incident solar rays onto the photovoltaic cell is arranged in the beam path in front of this photovoltaic cell. Further along the beam path in front of the lens is a tracking device according to the present invention. Thus, a photovoltaic module according to the invention offers the same advantages as those explained in detail with reference to a tracking device according to the invention. The photovoltaic cell is designed as a multilayer structure, significantly smaller than conventional single-layer photovoltaic cells, and can thus be produced relatively cost-effectively.The lens functionality makes it possible to still provide a large area of ​​incidence and, with the help of the tracking function of the tracking device, to ensure this even for a wide variety of angles of incidence and sun position situations. Such a photovoltaic module can of course also have two or more photovoltaic lens units next to each other, with either a separate tracking device being arranged for each photovoltaic lens unit or a tracking device extending across two or more photovoltaic lens units. Due to the fixed arrangement and thus the static alignment of the photovoltaic cell, it can also be provided with a passive heat sink on the back of the photovoltaic cell, for example. It should also be noted here that both direct tracking and focusing as well as indirect design are possible.With direct tracking, the tracking and focusing occurs directly on the photovoltaic cell. Alternatively or additionally, it is also conceivable for the focusing to take place on an absorber, which then transmits the tracked and focused light to a photovoltaic cell at a different location. For example, the use of fiber optic cables for such an absorber is conceivable.

[0028] It is also advantageous if, in a photovoltaic module according to the invention, the photovoltaic cell is at least partially surrounded by a secondary optics system for secondary bundling of incoming solar rays arranged downstream of the lens in the beam path. Despite the various tracking functions and the modification of the mirror surface, it may still be the case that, for extreme angles of incidence, a portion of the incoming solar rays is not focused by the lens onto the small photovoltaic cell in the desired manner. Stray light that does not reach the photovoltaic cell despite the multiple functions described can now, for example, be captured by such a secondary optics system next to the photovoltaic cell and then additionally redirected back to the photovoltaic cell.Such uncaptured or untracked sunlight can also be referred to as bypass light, so that by capturing this bypass light the efficiency of the photovoltaic module can be further increased even at extreme angles of incidence and at different positions of the sun.

[0029] Furthermore, it is an object of the present invention to provide a tracking method for tracking the beam path of a photovoltaic lens unit using a tracking device according to the invention. Such a tracking method comprises the following steps:

[0030] - Recording an actual incidence situation for solar rays,

[0031] - Recording the actual alignment of the photovoltaic lens unit,

[0032] - Moving the first mirror elements and / or the second mirror elements to track the beam path from the actual incidence situation to a centered incidence in the photovoltaic lens unit.

[0033] A tracking method according to the invention brings with it the same advantages as have been explained in detail with reference to a tracking device according to the invention and a photovoltaic module according to the invention.

[0034] It may be advantageous if, in a tracking method according to the invention, the detection of the actual alignment comprises at least one of the following steps: detecting an input of alignment parameters,

[0035] - Recording GPS information,

[0036] - Capturing angle information,

[0037] - Capturing compass information.

[0038] The above list is not exhaustive. In particular, individual parameters and information can be recorded by sensors. In the simplest case, however, the installer manually enters the actual orientation into a corresponding control module during installation of the photovoltaic module. However, automated information and thus data provided by the respective sensor can also be recorded using a gyroscope, a magnetometer, a position sensor, or similar sensor elements.

[0039] It can also be advantageous if, in a tracking method according to the invention, at least one of the following steps is provided for the detection of the actual incidence situation:

[0040] - Capturing photosensor information,

[0041] - Recording GPS information,

[0042] - Capturing time information.

[0043] The above list is also not exhaustive. Photosensors can determine the current light quantity, which can be used, for example, to calculate the current expected electrical output of the photovoltaic module. If the actual photovoltaic module output deviates significantly from the calculated output, it can be assumed that the ideal alignment is no longer maintained. This allows for readjustment / tracking of the tracking device according to the invention.

[0044] Position information from GPS sensors, and in particular time information regarding the time of day and year, can also be used to determine the expected angle of incidence of the sun at this position at this point in time of day and year from corresponding calendar information. Further advantages can also be achieved if a tracking method according to the invention also includes the determination of an actual mirror alignment of the first mirror elements and / or the second mirror elements. In addition to simply controlling a position, this also enables feedback of the actually achieved position of the respective mirror elements. For example, a digital electric motor can be used for the actuators, which allows very precise, controlled control as well as feedback regarding the achieved position.Stepper motors can also be used, which are more cost-effective than digital motor controllers. With such stepper motors, the tracking method can, for example, perform a calibration procedure at a specific time, for example, once a day, by moving to a mechanical stop.

[0045] Further advantages, features, and details of the invention will become apparent from the following description, which describes exemplary embodiments of the invention in detail with reference to the drawings. They show schematically:

[0046] Fig. 1 shows an embodiment of a photovoltaic module according to the invention,

[0047] Fig. 2 shows the embodiment of Figure 1 in an exclusion view,

[0048] Fig. 3 is a representation of a tracking device according to the invention,

[0049] Fig. 4 is a diagram of a photovoltaic lens unit,

[0050] Fig. 5 the photovoltaic lens unit of Figure 4 with different angles of incidence of sunlight,

[0051] Fig. 6 shows the representation of Figure 5 with a first angular position of the mirror elements,

[0052] Fig. 7 shows the representation of Figure 6 with a different angular position of the mirror elements,

[0053] Fig. 8 shows a detailed view of multi-part mirror elements in a retracted position, Fig. 9 shows the embodiment of Figure 8 with extended mirror elements,

[0054] Fig. 10 the embodiment of Figures 8 and 9 with extended mirror elements and

[0055] Fig. 11 shows the embodiment of Figures 8 to 10 with retracted mirror elements.

[0056] Figure 1 schematically shows a photovoltaic module 100 according to the invention. It is equipped with a photovoltaic lens unit 110 in its lower region. Incident sunlight can be focused onto a photovoltaic cell 114 via a lens 112, here designed as a Frenel lens. This focusing allows for a significant reduction in the geometric dimensions and the associated production costs for the photovoltaic cell 114. A secondary optics system 116 is provided around the photovoltaic cell 114 to also guide secondary bypass light back to the photovoltaic cell 114.

[0057] Since the photovoltaic module 100 of Figure 1 is to be mounted statically and thus immobile, a tracking device 10 is arranged above the lens 112. This tracking device is equipped with the two tracking frames 20 and 40, completely overlapping one above the other in a sandwich construction.

[0058] In Figure 2, the correlation of the individual components to one another is clearly visible in the exclusion diagram. From top to bottom, this structure begins with a transparent protective cover 12. Arranged below this is the first tracking frame 20, which has a plurality of individual mirror elements 22. Each of these mirror elements 22 can rotate about an adjustment axis 23. To implement this rotation as an adjustment movement, an adjustment actuator 25 is provided, which forms part of an adjustment device 24. By moving along the adjustment direction SR, the rotation and adjustment of the angular position for the first mirror elements 22, which will be explained in more detail later, takes place.

[0059] Arranged below, Figure 2 shows the second tracking frame 40. This is constructed essentially identically to the first mirror tracking frame 20 and accordingly has a plurality of mirror elements 42. Similar to the first mirror elements 22 between the upper sub-frame 20a and the lower sub-frame 20b, the second mirror elements 42 are also arranged between an upper sub-frame 40a and a lower sub-frame 40b. These also extend along adjustment axes SR (not shown in detail here), which allow a corresponding adjustment movement offset by 90 degrees along the adjustment direction SR shown here with the adjustment actuator 45 of the adjustment device 44.

[0060] Figure 3 shows the combination of the two tracking frames 20 and 40 in the tracking device 10 in more detail. Here, it can also be seen that a further translational bearing is provided in the height direction HR. If the actuating actuator 25 of the actuating device 24 is now moved from left to right or from right to left, the deflection shown in the height direction HR can be understood as a slotted guide and achieves a change in the distance between the two sub-frames 20a and 20b. In addition, of course, the desired change in the angular position for all mirror elements 20 is effective. In the same way, only offset by 90 degrees, a corresponding actuating movement in the actuating direction SR and in the height direction HR also takes place for the second tracking frame 40 arranged below.

[0061] Figure 4 schematically illustrates the photovoltaic lens unit 110. Here, it is clearly visible that a preferred embodiment of the lens 112 is a Frenell lens. It is also clearly visible how additional mirror surfaces, as secondary optics 116, reflect bypass light that has not been focused onto the photovoltaic cell 114 in the desired manner, back onto it, in order to further increase operational efficiency.

[0062] Figure 5 illustrates why a tracking function according to the invention offers such significant advantages. Two beam paths S are represented here by different dashed lines. When the beam path S of sunlight enters the Frenel lens of lens 112 at a substantially perpendicular angle, the desired focusing occurs on the small photovoltaic cell 114. When the sun is at a lower angle, the angle of incidence of the beam path S is correspondingly flatter, so that, due to the static arrangement of the lens function of lens 112, the beam path no longer focuses the sunlight on the photovoltaic cell 114, but rather at a distance from it. At this position of the sun, this incident sunbeam could therefore not generate any electricity on the photovoltaic cell 114.

[0063] Figures 6 and 7 show that, even at very shallow angles of incidence, the beam path S can be tracked such that it is always focused on the photovoltaic cell 114 by the lens 112. The flatter the angle of incidence of the beam path S, the flatter the angular position of the first mirror elements 22, shown here as a single mirror element 22, can be seen. This tracking of the angular position allows the angle of incidence on the lens 112 to be kept essentially constant. The constant angle of incidence, together with the constant lens function of the lens 112, thus leads to a constant or essentially constant focusing for the beam path S on the photovoltaic cell 114 at different incident positions of the sun.Even though Figures 6 and 7 only show one-dimensional tracking, for example in the east-west direction, this is made available for multi-axis tracking by combining the two tracking frames 20 and 40 with each other.

[0064] Figures 8, 9, 10 and 11 schematically show that a variation can be carried out not only along the adjustment direction SR, but also along the height direction HR. While in the vertical angular position of the mirror elements 22 in Figure 8 they have the maximum distance from one another, when the actuating actuator 25 moves along the adjustment direction, a conversion into the height direction HR is carried out by the slotted guide. This results in the lower sub-frame 20b in Figure 8 moving towards the upper sub-frame 20a in Figure 9. The distance between the two sub-frames 20a and 20b therefore decreases during this movement. This not only changes the angular position of the individual mirror elements 22, but also causes the sub-mirrors 20a, 20b, 42a and 42b to shift relative to one another, as shown in Figures 10 and 11.By means of different overlapping situations, which can be changed in a controlled manner by varying the height direction HR, the entire mirror surface of all mirror elements 22 and 42 can be varied in such a way that bypass light at the mirror elements 22 and 42 can be reduced to a minimum.

[0065] The above explanation of the embodiments describes the present invention exclusively by way of examples. List of reference symbols

[0066] 10 Tracking device

[0067] 12 transparent protective covers

[0068] 20 first tracking frame

[0069] 20a lower subframe

[0070] 20b upper subframe

[0071] 22 first mirror elements

[0072] 22a Partial mirror

[0073] 22b partial mirror

[0074] 23 first adjustment axis

[0075] 24 first adjusting device

[0076] 25 first actuator

[0077] 40 second tracking frame

[0078] 40a lower subframe

[0079] 40b upper subframe

[0080] 42 second mirror elements

[0081] 42a partial mirror

[0082] 42b partial mirror

[0083] 43 second adjustment axis

[0084] 44 second adjusting device

[0085] 45 second actuator

[0086] 100 photovoltaic modules

[0087] 110 Photovoltaic lens unit

[0088] 112 lens

[0089] 114 photovoltaic cells

[0090] 116 Secondary optics

[0091] S beam path

[0092] SR setting direction

[0093] HR altitude direction

Claims

Patent claims 1. Tracking device (10) for tracking a beam path (S) of a photovoltaic lens unit (110) depending on the position of the sun, comprising a first tracking frame (20) with a plurality of first mirror elements (22) movably mounted therein and a second tracking frame (40) with a plurality of second mirror elements (42) movably mounted therein in the beam path (S) after the first mirror elements (22), further comprising a first adjusting device (24) with a first adjusting actuator (25) for moving the first mirror elements (22) about first adjusting axes (23) between at least two different angular positions and a second adjusting device (44) with a second adjusting actuator (45) for moving the second mirror elements (42) about second adjusting axes (43) between at least two different angular positions, wherein the orientation of the first adjusting axes (23) differs from the orientation of the second adjusting axes (43).

2. Tracking device (10) according to claim 1, characterized in that each first mirror element (22) has its own first adjusting axis (23) and each second mirror element (42) has its own second adjusting axis (43), wherein the first adjusting axes (23) are aligned parallel to one another and / or the second adjusting axes (43) are aligned parallel to one another.

3. Tracking device (10) according to claim 2, characterized in that the first adjusting axes (23) span a first adjusting plane and / or the second adjusting axes (43) span a second adjusting plane, wherein in particular the first adjusting plane is aligned parallel or substantially parallel to the second adjusting plane and / or to a lens plane of the photovoltaic lens unit (110).

4. Tracking device (10) according to one of the preceding claims, characterized in that the first mirror elements (22) are designed to be rotatable about the first adjustment axes (23) and / or the second mirror elements (42) are designed to be rotatable about the second adjustment axes (43). Tracking device (10) according to one of the preceding claims, characterized in that the first actuating actuator (25) and / or the second actuating actuator (45) is / are designed for a translational actuating movement, in particular along an actuating direction (SR) transverse to the respective first actuating axes (23) and second actuating axes (43). Tracking device (10) according to one of the preceding claims, characterized in that the first mirror elements (22) and / or the second mirror elements (42) have a planar or substantially planar extension. Tracking device (10) according to one of the preceding claims, characterized in that the first mirror elements (22) and / or the second mirror elements (42) each have at least two partial mirrors (22a, 22b, 42a, 42b) which are mounted so as to be movable relative to one another for changing the mirror surface of the respective first mirror element (22) and / or second mirror element (42).Tracking device (10) according to claim 7, characterized in that the first actuating actuator (25) and / or the second actuating actuator (45) is / are mounted to be movable in a height direction (HR) for changing the height extension of the first tracking frame (20) and / or the second tracking frame (40) when performing the actuating movement for changing the mirror surface of the first mirror elements (22) and / or the second mirror elements (42). Tracking device (10) according to claim 8, characterized in that the first actuating actuator (25) and / or the second actuating actuator (45) interact directly or indirectly with a slotted guide for the movement along the height direction (HR).Tracking device (10) according to one of the preceding claims, characterized in that the first tracking frame (20) and / or the second tracking frame (40) each have a lower sub-frame (20a, 40a) and an upper sub-frame (20b, 40b), wherein the first mirror elements (22) and / or the second mirror elements (42) are movably mounted in each of the two sub-frames (20a, 20b, 40a, 40b). Tracking device (10) according to one of the preceding claims, characterized in that the first tracking frame (20) and the second tracking frame (40) are identical or substantially identical. Tracking device (10) according to one of the preceding claims, characterized in that the first tracking frame (20) and the second tracking frame (40) are arranged one behind the other in the beam path (S), in particular completely or substantially completely overlap. Tracking device (10) according to one of the preceding claims, characterized in that the first mirror elements (22) and / or the second mirror elements (42) have mirror foils at least in sections. Tracking device (10) according to one of the preceding claims, characterized in that a transparent protective cover (12) is arranged in front of the first tracking frame (20) in the beam path (S) to protect against mechanical damage and / or contamination.Tracking device (10) according to one of the preceding claims, characterized in that the first tracking frame (20) and / or the second tracking frame (40) has an outer contour which is geometrically similar to the outer contour of the lens (112) and / or the photovoltaic cell (114) of the photovoltaic lens unit (110). Photovoltaic module (100) for generating electrical current, comprising at least one photovoltaic lens unit (110) with a multilayer photovoltaic cell (114) and a lens (112) arranged in front of it in the beam path (S) for concentrating the incident solar rays onto the photovoltaic cell (114), wherein a tracking device (10) having the features of one of claims 1 to 15 is arranged in the beam path (S) in front of the lens (112). Photovoltaic module (100) according to claim 16, characterized in that the photovoltaic cell (114) is at least partially surrounded by a secondary optic (116) for secondary bundling of incident solar rays arranged in the beam path (S) after the lens (112). A tracking method for tracking a beam path (S) of a photovoltaic lens unit (110) by means of a tracking device (10) having the features of one of claims 1 to 15, comprising the following steps: - Recording an actual incidence situation for solar rays, - detecting an actual alignment of the photovoltaic lens unit (110), - Moving the first mirror elements (22) and / or the second mirror elements (42) to track the beam path (S) from the actual incidence situation to a centered incidence into the photovoltaic lens unit (110). Tracking method according to claim 18, characterized in that the detection of the actual orientation comprises at least one of the following steps: - Capturing an input of alignment parameters - Capture GPS information - Capturing angle information - Acquisition of compass information. Tracking method according to one of claims 18 or 19, characterized in that the acquisition of the actual incidence situation comprises at least one of the following steps: - Capturing photosensor information - Capture GPS information Capturing time information Tracking method according to one of claims 18 to 20, characterized in that an actual mirror alignment of the first mirror elements (22) and / or the second mirror elements (42) is additionally determined.

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