Brightness sensor for detecting the brightest direction of irradiance in the sky and for tracking a photovoltaic module, sensor system and photovoltaic module device

Abstract

Brightness sensor (101, 103) for detecting a brightest direction of irradiation in the sky and for tracking photovoltaic modules to the brightest direction of irradiation, wherein the brightness sensor (101, 103) is associated with an electronic circuit device (141) for power supply and data evaluation, the brightness sensor (101, 103) has a connection for a power supply, a mounting base (105) with a plane (107) and at least two light-dependent resistors, characterized in that at least one shading plate (109) with a longitudinal dimension substantially perpendicular to the plane (107) of the mounting base (105) is arranged on the mounting base (105), wherein the shading plate (109) has two opposing plate surfaces and a material thickness,and a first light-dependent resistor (111) is arranged at a distance from the first plate surface and a second light-dependent resistor (112) is arranged opposite it at a distance from the second plate surface, and a respective photoactive surface (115) of the first light-dependent resistor (111) and of the second light-dependent resistor (112) is aligned substantially parallel to the plane (107), so that in the event of reaching a target position of the brightness sensor (101, 103) during the tracking of the photovoltaic module, the first light-dependent resistor (111) or the second light-dependent resistor (112) illuminated in a tracking direction is darkened by means of the shading plate (109) and the tracking can be terminated.

Description

[0001] The invention relates to a brightness sensor for detecting a brightest direction of incidence in the sky and for tracking photovoltaic modules to the brightest direction of incidence, wherein the brightness sensor can be associated with an electronic circuit device for power supply and data evaluation, and the brightness sensor has a connection for a power supply, a mounting base with a plane and at least two light-dependent resistors.

[0002] Brightness sensors, also known as sun tracking sensors, are used in photovoltaic systems to determine the direction of the brightest sunlight in the sky and to provide a control signal for tracking the photovoltaic modules. A disadvantage of existing sun tracking sensors is that they are often only suitable for single-axis tracking (tilting from east to west), and tracking via azimuth rotation cannot be reliably performed in all lighting conditions without manual intervention from a user.

[0003] Furthermore, it is known to astronomically control solar tracking via numerical control to follow the sun's path every minute of the year. A disadvantage of this method is that strong radiative breaks in clouds and reflective clouds located outside the sun's path and to the side and / or behind the solar panel, which contribute a large amount of radiation, cannot be coupled in to increase yield, as this would typically require rotating the tracking system by 90 to 200°.

[0004] CN 101 625 232 A discloses a solar tracking sensor with an isosceles triangular mount, wherein two photovoltaic cells are mounted on each of the two inclined surfaces of the isosceles triangular mount and a double-sided reflector lens is attached to the angle bisector of the isosceles triangular mount. Such a sensor enables the formation of a one-dimensional solar tracking system.

[0005] CN 2014 767 82 U describes a solar tracking sensor designed as a cylinder with an upper opening, wherein a channel aperture, a cross aperture, and a transverse aperture are arranged inside the cylinder. This creates four channels arranged at right angles to each other inside the cylinder, with a photoresistor mounted on a transverse partition in each channel. Due to the arrangement of the photoresistors within the channels, the detection field is severely restricted.

[0006] From DE 100 43 525 A1, a detection device in the form of a three-sided pyramid is known, in which a solar cell surface is located on each side. The energy absorbed by these solar cells is used to control a motor of a solar power system. Depending on the amount of current supplied by one of the solar cell surfaces, the solar power system is rotated in the direction of the corresponding solar cell surface. This allows for a wide detection field of up to 360°. Due to the pyramid's structure, when the pyramid's apex is facing the sun, only a slow shading of the direction of strongest irradiance occurs, allowing the target position to be overshot by several degrees without the tracking mechanism needing to be switched off immediately.

[0007] The applicant's patent DE 20 2011 104 051 U1 describes sensors and electronics for controlling ground-mounted tracking systems with photovoltaic modules, in which a reliable stopping of an active axis is achieved by means of an end-position circuit. A cloud cover sensor and a radiation intensity sensor are used to optimize energy yield from photovoltaic arrays. The radiation intensity sensor consists of a round wire with a plastic coating, to which a photoresistor with a pendulum weight is mounted. The cloud cover sensor for zenith alignment of the solar array in the presence of pure diffusion radiation consists of an aluminum sheet with a slight bend angle, so that when the solar array is perpendicularly oriented towards direct sunlight, a mounted upper photoresistor is slightly shaded, thereby illuminating a mounted lower photoresistor more intensely.The mounted photoresistors are surrounded by a cylindrical glass cover that is closed at the front.

[0008] DE 101 42 214 A1 describes a method for tracking sunlit surfaces according to the position of the sun based on the exceedance of certain threshold values ​​of a brightness sensor at specific times. Furthermore, CH 705 824 B1 relates to a solar power system with single-axis and dual-axis solar tracking with a support frame made of metal tubes, DE 297 07 201 U1 to a solar-tracking cylindrical rotary device for receiving, holding, and rotating at least one solar module, and EP 2 607 819 A2 to a solar system with a tracking device having at least one rotating unit rotatable about at least one elevation axis, which is designed asymmetrically and / or eccentrically relative to at least the elevation axis.

[0009] Consequently, known sensors for tracking photovoltaic modules have the disadvantages that they have a severely limited detection field, can only detect the sun's path if the sensor is already essentially aligned with the irradiance, especially up to 45°, can only achieve an inaccurate approach to the sun's position with a deviation from a target position of 10° to 20°, can only reliably implement a single-axis, tilting east-west tracking, and / or cannot detect reverse irradiance after the sun's return in the west or east after cloud passage and rotation by 90° to 180°, and consequently the tracking can become stuck within the adjustment range limit.

[0010] The purpose of the invention is to improve the state of the art.

[0011] The problem is solved by a brightness sensor for detecting the brightest direction of illumination in the sky and for tracking photovoltaic modules towards the brightest direction of illumination, wherein the brightness sensor is associated with an electronic circuit device for power supply and data evaluation, the brightness sensor has a connection for a power supply, a mounting base with one plane and at least two light-dependent resistors, and at least one shading plate with a longitudinal dimension substantially perpendicular to the plane of the mounting base is arranged on the mounting base, wherein the shading plate has two opposing plate surfaces and a material thickness.and a first light-dependent resistor is arranged at a distance from the first plate surface and a second light-dependent resistor is arranged opposite it at a distance from the second plate surface, and a respective photoactive surface of the first light-dependent resistor and the second light-dependent resistor is oriented essentially parallel to the plane, so that in the event of reaching a target position, the brightness sensor, during the tracking of the photovoltaic module, darkens the first light-dependent resistor or the second light-dependent resistor illuminated in a tracking direction by means of the shading plate and the tracking can be terminated.

[0012] This provides a brightness sensor that reliably and with high accuracy enables the tracking of photovoltaic modules to the brightest direction of irradiance at the current position of the sun. Because the brightness sensor detects the currently brightest direction of irradiance in the sky (sun, reflecting clouds, breaks in the clouds) and can output a corresponding control signal to a tracking device, the tracking of the photovoltaic modules can be carried out with very high precision. Consequently, the surface normal of the solar field can always be aligned in such a way that the maximum possible yield from a solar array is achieved. In addition to increasing the yield of the photovoltaic system by means of at least one brightness sensor according to the invention, the precise tracking offers further advantages depending on the application. For example, it can be used to operate sun-focusing systems, which must be aligned exactly to their focal point.

[0013] Thus, the brightness sensor according to the invention has at least two light-dependent resistors, which are designed as frontal light sensors. The shading plate arranged between the two light-dependent resistors, the longitudinal dimension of which is perpendicular to the photoactive surfaces and the plane of the mounting base, ensures that the brightness sensor always finds the optimum irradiance with a deviation of < 3°, in particular of 2°, preferably of < 1°.

[0014] During tracking, the shading plate ensures that the light-dependent resistor in the desired direction is strongly illuminated, while the other light-dependent resistor in the opposite direction is shaded. If the strongest illumination is detected and passed during tracking, even a small error angle will cause the light-dependent resistor in the desired direction to suddenly be shaded, and the positioning process can be terminated with high accuracy relative to the target position using the associated electronic circuitry and / or the tracking device.

[0015] The brightness sensor with at least two light-dependent resistors for an elevation axis detects the brightest source of irradiance in the detection field of 90° between the ground and the sky around the brightness sensor.

[0016] A key concept of the invention is based on the fact that a shading plate, with its longitudinal dimension aligned with the solar field surface normal, is arranged on both sides between two light-dependent resistors. The two light-dependent resistors have a significantly smaller dimension than the longitudinal dimension of the shading plate, so that when tracking, upon reaching the target position using the shading plate, the light-dependent resistor previously illuminated in the tracking direction (steering direction) suddenly darkens, thereby increasing its resistance value. Meanwhile, the second light-dependent resistor, facing the irradiation, is fully illuminated and has a lower resistance value. This difference in resistance values ​​generates the desired steering signal in the associated electronic circuitry and can be used to switch off and / or control the tracking device.

[0017] The following terms will be explained: A "brightness sensor" (also called a "light sensor") is, in particular, at least one electronic component or assembly that converts light into an electrical signal using the photoelectric effect and / or has an electrical resistance that depends on the incident radiation. The brightness sensor can, in particular, utilize an external or an internal photoelectric effect. The brightness sensor has, in particular, at least two light-dependent resistors and a shading plate, which are mounted on a mounting base. Thus, the brightness sensor is constructed from a few standard components, in particular two to four light-dependent resistors, the mounting base, and the shading plate. Consequently, the brightness sensor can be manufactured simply and cost-effectively.

[0018] A "light-dependent resistor" (also "photoresistor" or "LDR") is, in particular, a light-sensitive electrical resistor. The more light falls on the light-dependent resistor, the lower its resistance becomes. The light-dependent resistor typically comprises a thin layer of photosensitive semiconductor material, a ceramic substrate, and two electrical terminals. The light-dependent resistors and / or the brightness sensor, in particular, have an IP66 protection rating and are therefore dustproof and protected against powerful water jets. The diameter of the light-dependent resistor is typically in the range of 3.0 mm to 7.0 mm, particularly 3.5 mm to 6.0 mm, and preferably 4.0 mm to 5.0 mm. The height of a light-dependent resistor is usually in the range of 5.0 mm to 8.0 mm.

[0019] The term "brightest direction of incidence" refers specifically to the direction of greatest illuminance reaching the brightness sensor. The brightest direction of incidence can originate from above, from the sky, and / or from the surrounding environment, encompassing a 360° radius around the brightness sensor. In the sky, the brightest direction of incidence can be radiation from the sun, a reflective cloud, and / or a break in the clouds. However, the brightest direction of incidence can also originate from a snow-covered surface, a body of water, or any other reflective object.

[0020] A "shading plate" (also called a shading sheet) is, in particular, a component laid out in a plane. The shading plate has, in particular, two opposing plate surfaces and a material thickness positioned between them. The material thickness of the shading plate is, in particular, significantly less than its longitudinal dimension. The shading plate is oriented in its longitudinal dimension, in particular, along the direction of the solar field surface normal and is thus essentially perpendicular to the plane of the mounting base. "Essentially perpendicular" means, in particular, that the shading plate's longitudinal dimension need not necessarily be at a 90° angle to the plane of the mounting base, but may also deviate from 90° by a few degrees.For example, the shading panel can be mounted at an angle of 80° to 100° to the plane of the mounting base. Thus, the shading panel is positioned with one transverse edge against the mounting base and with another transverse edge positioned opposite it in its longitudinal dimension, freestanding in the surrounding area. The shading panel is made of a particularly rigid material. For example, the shading panel can be made of plastic, aluminum, and / or wood.

[0021] The term "azimuth axis" refers to a vertical axis on the Earth's surface, around which the azimuth is a horizontal angle oriented towards a cardinal direction. The azimuth is usually given as a clockwise angle measured from north (north = 0°, east = 90°, south = 180°, west = 270°).

[0022] The elevation axis (also called the altitude axis) is a horizontal axis rotating relative to the Earth's surface, around which a rotation occurs from the horizon at 0° and at the zenith at 90°. Thus, the altitude angle indicates how high an object or the brightest direction of light is above the horizon.

[0023] An "electronic circuit device" (also called an "electronic unit") is, in particular, a system of interconnected electrical and / or electronic components for electrical signal processing, signal evaluation, control, regulation, and / or for supplying power to a brightness sensor or multiple brightness sensors. The electronic circuit device generates, in particular, a suitable control signal from the resistance of the respective brightness sensor for a higher-level control and / or regulation system of a tracking device. The electronic circuit device comprises, in particular, an electronic circuit board and / or a switching board. The electronic circuit device may also include a microcontroller or be a component of a microcontroller.The electronic circuit device includes, in particular, a measuring bridge consisting of the connected light-dependent resistors of the brightness sensors and 1 kΩ fixed resistors, in conjunction with a bridge H-branch consisting, in particular, of a 2.2 kΩ fixed resistor and a 10 kΩ potentiometer for signal attenuation. Furthermore, the electronic circuit device has antiparallel-connected operational amplifiers on its circuit board, which can measure a voltage drop across the 2.2 kΩ fixed resistor.

[0024] In a further embodiment of the brightness sensor, the first light-dependent resistor and the second light-dependent resistor each have a distance in a range of 5 mm to 60 mm, in particular 10 mm to 50 mm, preferably 20 mm to 40 mm, from the respective plate surface.

[0025] For a given length of the shading plate, the speed of the shading and thus the error angle during tracking can be adjusted via the distance between the two light-dependent resistors and to the respective plate surface.

[0026] To achieve high tracking accuracy, the shading plate has a length in the range of 20 mm to 150 mm, in particular from 30 mm to 100 mm, preferably from 80 mm to 90 mm.

[0027] Thus, the extent and speed of the shading can be adjusted by changing the length of the shading plate. This allows for a tracking accuracy of at least 3°, in particular 2°, and preferably 0.3°. If the strongest irradiance is detected by the brightness sensor and subsequently traversed by a tracking device, even a small error angle, depending on the length of the shading plate, is sufficient to shade the target setting device and, consequently, to deactivate the tracking device.

[0028] The shadow cast grows rapidly with the tangent function of the error angle relative to the irradiance and the length of the shading plate. Consequently, the degree of shading of the respective light-dependent resistor can be determined as a function of the error angle by adjusting the length of the shading plate. This can be used to generate a very high positional accuracy of up to 0.3° for sun-focusing systems. For tracking systems for photovoltaic modules, however, a positional accuracy in the range of 2.0° to 5.0° is usually sufficient to achieve their maximum yield.

[0029] In a further embodiment, the brightness sensor has a third light-dependent resistor and a fourth light-dependent resistor, wherein the third light-dependent resistor is arranged with a rotation angle of at least 125° to the first plate surface and the fourth light-dependent resistor is arranged with a rotation angle of at least 125° to the mounting base.

[0030] Thus, in addition to the two frontal light-dependent resistors, whose active photon surface is aligned with the solar field normal, the brightness sensor features two further light-dependent resistors mounted laterally and / or backwards, each rotated at least 125° relative to the plane of the shading plate. For optimal tracking in the two directions of east and west, the brightness sensor therefore has four light-dependent resistors. This allows for the implementation and control of single- or dual-axis azimuth tracking systems for photovoltaic modules, increasing the yield from the photovoltaic arrays by approximately 28 to 40%, depending on the tracking system and location, compared to a fixed south-facing installation.The brightness sensor ensures the reliable and accurate detection of the brightest light source, advantageously capturing it both in the sky and in the entire surrounding area. The sensor achieves a wide 360° detection field of the brightest light source with high positional accuracy, specifically less than 2% deviation from the target position. A particular advantage is its ability to detect both direct and diffuse light sources, ensuring the solar array is always aligned with the strongest light source. In cloudy conditions, this can include breaks in the clouds to the side of the sun's position or even reflective clouds in the opposite direction. Reflections from water and / or snow surfaces in the vicinity are also taken into account.

[0031] With such a brightness sensor for the azimuth axis, featuring a 360° detection field for irradiance intensity, it is ensured that, under no lighting conditions, the tracking system will remain aligned with a reflective cloud when it should be tracking the much more productive sun, which is located exactly 180° behind the solar array. Furthermore, when the brightness sensor is backlit from the east or west, the tracking system cannot become stuck in the opposite end position.

[0032] A “rotation angle” is, in particular when viewed from the side on the brightness sensor and thus when viewed from the side on an upwardly directed solar field surface normal, an angle between the respective outer and / or facing plate surface of the shading plate and a normal which is perpendicular to the photoactive surface of the third light-dependent resistor or fourth light-dependent resistor.

[0033] In order to optimally detect lateral and / or rearward illumination, the third light-dependent resistor and the fourth light-dependent resistor are each arranged with a rotation angle in a range of 125° to 145°, in particular 130° to 140°, preferably 133° to 137°, relative to the first plate surface or the second plate surface of the shading plate.

[0034] In another embodiment of the brightness sensor, the third light-dependent resistor and the fourth light-dependent resistor are each arranged at an angle of inclination in a range of 10° to 30° between a perpendicular on the respective photoactive surface and the plane of the mounting base.

[0035] To optimally detect and evaluate lateral and rearward illumination, the third and fourth light-dependent resistors can each be fixed to the mounting base at an angle of 10° to 30° to the plane of the mounting base, pointing upwards. For example, each light-dependent resistor can be mounted on an outer wall of the mounting base with its photoactive surface angled upwards, thus towards the sky. In this case, the angle of inclination is positioned between a perpendicular on the outer wall of the mounting base (and thus between the plane) and a perpendicular on the respective photoactive surface of the light-dependent resistor.

[0036] In a further aspect of the invention, the problem is solved by a sensor system for detecting a brightest direction of irradiation in the sky and for tracking a photovoltaic module on two axes, wherein the sensor system comprises at least one previously described first brightness sensor according to one of claims 1 or 2 for an elevation axis and at least one previously described second brightness sensor according to one of claims 3 to 6 for an azimuth axis.

[0037] This provides a sensor system that can reliably detect the brightest direction of incidence in the sky and the lateral and rear surroundings and use it for tracking photovoltaic modules.

[0038] In another embodiment of the sensor system, the first brightness sensor is arranged in a direction along the plane of the mounting base above the second brightness sensor.

[0039] The first and second brightness sensors can be mounted on the upper, skyward-facing edge of the tracking device's supporting frame using their respective mounting bases. A sufficiently large distance between the two brightness sensors, for example approximately ≥ 10 cm, ensures that there is no mutual shading that would impair their function.

[0040] To enable optimal alignment of the brightness sensors and thus precise tracking of photovoltaic modules, the first brightness sensor is arranged rotated by 90° Cartesian to the second brightness sensor.

[0041] Thus, the plane of the shading plate of the first brightness sensor for the elevation axis is aligned parallel to the ground or the sky plane when the sensor is erect and / or tracked. The plane of the shading plate of the second brightness sensor for the azimuth axis, therefore, divides the detection field into an east and a west area when the tracker is in a southerly position, thereby achieving optimal tracking between these areas. The Cartesian arrangement of the two brightness sensors relative to each other enables the determination of the sun's position and / or the direction of the brightest irradiance, as each sensor side observes one hemisphere in elevation and one in azimuth.

[0042] In an additional aspect of the invention, the problem is solved by a photovoltaic module device comprising at least one photovoltaic module, an electronic circuit device and a tracking device, wherein the tracking device has an actuator and is adjustable at least one-axis or two-axis by means of the actuator, and the photovoltaic module device comprises at least one previously described brightness sensor or sensor system.

[0043] Thus, a photovoltaic module device is provided in which suitable control signals, such as east, west, up and / or down, can be used from the differently illuminated light-dependent resistors of the brightness sensor or brightness sensors by means of the electronic circuit device and the tracking device, in order to ensure optimal tracking to the currently brightest irradiance source and thus the highest power input.

[0044] A "tracking device" is understood to mean, in particular, any device suitable for tracking one or two or more photovoltaic modules towards the brightest direction of the incoming sunlight. The tracking device includes, in particular, one or two or more actuators. The tracking device specifically performs the rotation and / or height adjustment of at least one photovoltaic module and / or its mounting frame. The photovoltaic modules are, in particular, arranged on at least one solar tracking device.

[0045] In addition to brightness sensors, the photovoltaic module device can also include other sensors, such as at least one temperature sensor, one wind sensor, and / or one snow load sensor. Preferably, the photovoltaic module device is controllable and / or adjustable via remote maintenance.

[0046] The invention will now be explained in more detail using exemplary embodiments. These will show... Fig. 1 A highly schematic cross-sectional representation of a first brightness sensor and a second brightness sensor, Fig. 2 a highly schematic cross-sectional representation of a sensor system, and Fig. 3 A highly schematic representation of an electronic circuit device with symbols used.

[0047] A first brightness sensor 101 for an elevation axis has a mounting base 105 with a plane 107 (mounting plane). A shading plate 109 is arranged on one upper side of the mounting base 105, the shading plate 109 extending longitudinally along a solar field surface normal 125, which is perpendicular to the plane 107. The shading plate 109 has two opposing plate surfaces on each side. Spaced apart from the respective plate surface of the shading plate 109, on the Fig. On the left side shown in Figure 1, a first light-dependent resistor 111 and on the right side a second light-dependent resistor 112 are arranged. The first light-dependent resistor 111 and the second light-dependent resistor 112 each have a photoactive surface 115, which is arranged parallel to the plane 107 and perpendicular to the solar field surface normal 125, so that rays from an irradiation direction 117 can fall onto the respective photoactive surface 115 from the outside.

[0048] A second brightness sensor 103 for an azimuth axis is configured with respect to the arrangement and orientation of the first light-dependent resistor 111 and the second light-dependent resistor 112 as described above for the first brightness sensor 101. The second brightness sensor 103 additionally has a third light-dependent resistor 113 and a fourth light-dependent resistor 114 ( Fig. 1) The third light-dependent resistor 113 is arranged at a rotation angle 121 of 135° between the left surface of the shading plate 109 and a normal on a photoactive surface 115 of the third light-dependent resistor 113 on the mounting base 105, wherein the third light-dependent resistor 113 is aligned at an angle of inclination 123 of 17° between the plane 107 and a perpendicular on the photoactive surface (and thus the side wall) of the third light-dependent resistor 113 at the outermost left edge of the mounting base 105. Likewise, a fourth light-dependent resistor 114 is arranged at the right edge of the mounting base 105 at a rotation angle 121 of 135° between the right surface of the shading plate 109 and a normal on a photoactive surface 115 of the fourth light-dependent resistor 114. Fig. 1), wherein the fourth light-dependent resistor 114 is mounted on the mounting base 105 with an angle of inclination 123 of 17° between the plane 107 and a side wall (and thus a perpendicular on the photoactive surface) of the fourth light-dependent resistor 114 (see Fig. 2).

[0049] A sensor system 131 has a support frame 133. The first brightness sensor 101 and the second brightness sensor 103 are each mounted on the support frame 133 with their mounting bases 105. The first brightness sensor 101 is positioned above the second brightness sensor 103, spaced apart from it. The shading plate 109 of the first brightness sensor 101 and the shading plate 109 of the second brightness sensor 103 are each arranged parallel to the solar field surface normal 125. However, the first brightness sensor 101 for the elevation axis, located above the second brightness sensor 103 for the azimuth axis, is rotated by 90° with respect to its shading plate 109 relative to the shading plate 109 of the second brightness sensor 103. Fig. 2).

[0050] The first brightness sensor 101 and the second brightness sensor 103 are associated with an electronic circuit device 141 of a photovoltaic module device (not shown). The electronic circuit device 141 comprises a circuit board 143 with electronic components. The following symbols 145 are used for the electronic components: resistor 151, potentiometer 152, operational amplifier 153, light-dependent resistor 154, ground potential point 155, potential point 156 for connected conductor tracks, conductor tracks 157, terminal 158, and circuit board boundary 159. The electronic circuit device 141 for evaluating the signals from the first brightness sensor 101 and the second brightness sensor 103 has terminals K19 and K110 for supplying the circuit with 5 V DC voltage. Terminals K13 and K14 of the electronic circuit device 141 are connected to terminals K21 and K23 of the second brightness sensor 103 for the azimuth adjustment direction.Here, the light-dependent resistors 111, 112, 113, 114 (symbol 154 in . Fig.3) The second brightness sensor 103 is a Wheatstone bridge with 1 kΩ fixed resistors connected in series. Depending on the illumination levels of the light-dependent resistors 111 to 114, the resistance values ​​change, causing the Wheatstone bridge to become unbalanced under identical illumination. This unbalance occurs when the first light-dependent resistor 111 and the second light-dependent resistor 112, located on opposite sides of the shading plate 109, as well as the third light-dependent resistor 113 and the fourth light-dependent resistor 114, located on opposite edges of the mounting base 105, are illuminated differently. This results in voltage values ​​varying in magnitude and direction across the bridge's H-branch (2.2 kΩ resistor 151 and 10 kΩ potentiometer 152). These voltage values ​​are sampled by two antiparallel operational amplifiers 153 via the 2.2 Ω resistor 151.When the threshold voltages of operational amplifier 153, or higher values, are applied in the positive gain direction, the high signal amplification results in a logic "on" signal at its output. Depending on the direction of travel, this is terminal K11 or K12. This "on" signal represents an east or west direction of travel and acts directly on a drive controller (not shown) of the tracking device to switch on the associated actuator (not shown). Alternatively, the "on" signal can be applied to a microcontroller to implement additional, software-implemented functions as a control filter. Simultaneously, the antiparallel operational amplifier of the opposite direction receives a voltage in its negative gain direction due to shading by the shading plate 109, with its output signal being 0.This eliminates the risk of simultaneously controlling an actuator in two different positioning and / or rotation directions. The 10 kΩ potentiometer 152 serves to reduce the direction-of-control voltage drop across the 2.2 kΩ resistor 151 and thus across the operational amplifier 153, ensuring that both operational amplifier outputs output the logic zero signal in the event of slight, but defined, lighting imbalances, thereby preventing oscillatory positioning activity.

[0051] Terminals K17 and K18 of the electronic circuit unit 141 are connected to terminals K24 and K25 of the first brightness sensor 101 for the elevation axis and the corresponding elevation control unit. The corresponding signals for the "up" or "down" direction are generated analogously to the second brightness sensor 103 described above. Depending on the direction of movement, the corresponding control signal is present at terminal K15 or K16 as a logical input signal. Additionally, a light intensity value can be measured at terminal K18 to switch between operating modes: sunny, cloudy, dark, and night.

[0052] The first brightness sensor 101 and the second brightness sensor 103 are supplied with a DC voltage of 5 V by means of the electronic circuit device 141. The first light-dependent resistor 111 and the second light-dependent resistor 112 of the first brightness sensor 101 and the second brightness sensor 103 each detect the direction of forward and lateral irradiation up to approximately 110° to the right or left onto the solar field.If the first light-dependent resistor 111 and the second light-dependent resistor 112 are positioned directly in the direction of illumination 117 by means of the electronic circuit device 141 and the tracking device, the two photoactive surfaces 115 of the first light-dependent resistor 111 and the second light-dependent resistor 112 are illuminated equally, since the respective shading plate 109 casts its existing "zenith shadow" directly onto the mounting base 105, and the first light-dependent resistor 111 and the second light-dependent resistor 112 are correspondingly unshaded. Consequently, the target position is achieved. However, if the direction of illumination 117 comes from further east or west, the respective shading plate 109 shades the first or second light-dependent resistor 111, 112 on the far side, thereby increasing its resistance coefficient.In contrast, the opposite, light-dependent first or second resistor 111, 112, facing the irradiation, is fully illuminated and exhibits a correspondingly low resistance value. In this case, the imbalance of the resistance values ​​generates the direction-of-control signal in the electronic circuit device 141 via the bridge H-branch.

[0053] However, if the azimuth axis is tracked by more than 110° relative to the detected sun position, the first light-dependent resistor 111 and the second light-dependent resistor 112 of the first brightness sensor 101 will no longer be able to return the tracking to its original position when the sun returns. If the tracking is more than 180° relative to the sun position, there is even a risk that an incorrect control signal could be triggered using only the first light-dependent resistor 111 and the second light-dependent resistor 112, causing the tracking device to lock in this end position. These two disadvantages do not exist with the second brightness sensor 103, since the two rear-mounted third and fourth light-dependent resistors 113 and 114 scan the area behind and to the sides around the shading plate 109.The third and fourth light-dependent resistors 113, 114 are each electrically connected in parallel to the first light-dependent resistor 111 and the second light-dependent resistor 112. Thus, each direction of control has one forward-facing light-dependent resistor 111, 112 and one backward-facing light-dependent resistor 113, 114. The parallel connection of the forward-facing light-dependent resistors 111, 112 and the backward-facing light-dependent resistors 113, 114 therefore affects the direction of control of the bridge circuit. In this case, the more intensely illuminated light-dependent resistor 111, 112, 113, or 114 (154) dominates the generation of the control signal due to its reduced resistance value. During a reverse solar return, one of the two backward-facing light-dependent resistors 113, 114 is illuminated and overdrives the weakly illuminated forward-facing light-dependent resistors 111, 112.The tracking device now points towards the brightly illuminated rear light-dependent resistor 113, 114 and thus finds its way back to the sun or another radiant point in the sky from any position.

[0054] Thus, a sensor system 131 with a first brightness sensor 101 and a second brightness sensor 103 and an electronic circuit device 141 is provided, which ensures precise and safe tracking of photovoltaic modules along both the elevation and azimuth axes in the entire irradiance field of 360°. Reference symbol list 101 first brightness sensor 103 second brightness sensor 105 Mounting bases (fixing bases) 107 Level (Assembly level) 109 Shading plate 111 first light-dependent resistor 112 second light-dependent resistor 113 third light-dependent resistor 114 fourth light-dependent resistor 115 photoactive area 117 Direction of irradiation 121 Rotation angle (mounting angle between shading plate and photoactive surface of the third or fourth light-dependent resistor) 123 Angle of inclination (mounting angle between a plane and a perpendicular on the photoactive surface of the third or fourth light-dependent resistor, directed towards the sky) 125 Solar field surface normals 131 Sensor system 133 support frames 141 Electronic circuit device 143 Electronic circuit board 145 Symbols Used 151 Resistance, z = digit of the resistance value, decade in k or M, unit: Ω 152 Potentiometers, z = digits of the resistance values, decade in k or M. Unit: Ω 153 operational amplifiers 154 Light-dependent resistance 155 Potential point ground, for connection with hook-up wire to the ground terminal 156 Potential point, connected conductor tracks 157 Conductor track, conductive connection in circuits 158 terminal 159 Circuit board boundary QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 101 625 232 A

[0004] CN 2014 767 82 U

[0005] DE 100 43 525 A1

[0006] DE 20 2011 104 051 U1

[0007] DE 101 42 214 A1

[0008] CH 705 824 B1

[0008] DE 297 07 201 U1

[0008] EP 2 607 819 A2

[0008]

Claims

[1] Brightness sensor (101, 103) for detecting a brightest direction of illumination in the sky and for tracking photovoltaic modules to the brightest direction of illumination, wherein the brightness sensor (101, 103) is associated with an electronic circuit device (141) for power supply and data evaluation, the brightness sensor (101, 103) has a connection for a power supply, a mounting base (105) with a plane (107) and at least two light-dependent resistors, characterized by, that at least one shading plate (109) with a longitudinal dimension substantially perpendicular to the plane (107) of the mounting base (105) is arranged on the mounting base (105), wherein the shading plate (109) has two opposing plate surfaces and a material thickness, and a first light-dependent resistor (111) is spaced apart from the first plate surface and a second light-dependent resistor (112) is arranged opposite it, spaced apart from the second plate surface, and a respective photoactive surface (115) of the first light-dependent resistor (111) and of the second light-dependent resistor (112) is oriented substantially parallel to the plane (107), such that in the event of reaching a target position of the brightness sensor (101,103) during the tracking of the photovoltaic module, a darkening of the first light-dependent resistor (111) or the second light-dependent resistor (112) illuminated in a tracking direction is achieved by means of the shading plate (109) and the tracking can be terminated. [2] Brightness sensor (101, 103) according to claim 1, characterized by , that the first light-dependent resistor (111) and the second light-dependent resistor (112) each have a distance in a range of 5 mm to 60 mm, in particular 10 mm to 50 mm, preferably 20 mm to 40 mm, from the respective plate surface. [3] Brightness sensor (101, 103) according to claim 1 or 2, characterized by , that the shading plate (109) has a length in a range of 20 mm to 150 mm, in particular from 30 mm to 100 mm, preferably from 80 mm to 90 mm. [4] Brightness sensor (101, 103) according to one of the preceding claims, wherein the brightness sensor (103) has a third light-dependent resistor (113) and a fourth light-dependent resistor (114), characterized by , that the third light-dependent resistor (113) is arranged with respect to the first plate surface and the fourth light-dependent resistor (114) is arranged with respect to the second plate surface with a rotation angle (121) of at least 125° on the mounting base (105). [5] Brightness sensor (103) according to claim 4, characterized by , that the third light-dependent resistor (113) and the fourth light-dependent resistor (114) are each arranged with the rotation angle (121) in a range of 125° to 145°, in particular 130° to 140°, preferably 133° to 137°, to the first plate surface or the second plate surface of the shading plate (109). [6] Brightness sensor (103) according to claim 3 or 4, characterized by, that the third light-dependent resistor (113) and the fourth light-dependent resistor (114) are each arranged with an angle of inclination (123) in a range of 10° to 30° between a perpendicular on the respective photoactive surface (115) and the plane (107) of the mounting base (105) on the mounting base (105). [7] Sensor system (131) for detecting a brightest direction of irradiation in the sky and for two-axis tracking of a photovoltaic module, characterized by , that the sensor system (131) has at least one first brightness sensor (101, 103) according to one of claims 1 or 2 for an elevation axis and at least one second brightness sensor (103) according to one of claims 3 to 6 for an azimuth axis. [8] Sensor system (131) according to claim 7, characterized by , that the first brightness sensor (101) is arranged in a direction along the plane (107) of the mounting base (105) above the second brightness sensor (103). [9] Sensor system according to claim 6 or 7, characterized by , that the first brightness sensor (101) is arranged rotated by 90° Cartesian to the second brightness sensor (103). [10] Photovoltaic module device comprising at least one photovoltaic module, an electronic circuit device (141) and a tracking device, wherein the tracking device has an actuator and is adjustable by means of the actuator at least in one or two axes, characterized by that the photovoltaic module device has at least one brightness sensor (101, 103) according to one of claims 1 to 6 or a sensor system (131) according to claims 7 to 9.

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