DE102010037776A1 - Adjusting device for aligning solar module of photovoltaic system installed on house roof with respect to condition of sun for conversion of solar energy into electrical energy, has measuring device detecting power produced by module - Google Patents

Abstract

The device has a modular mast (4) rotatably supported around a vertical axis, and a solar module or a frame (1) pivotably arranged at the modular mast. A measuring device detects power produced by the solar module. A gear motor displaces the modular mast in rotary movement. A cable retractor and position detection devices are arranged at the mast. An end rotational angle of the mast is predetermined by an end switch. A data detection device is connected with a central microprocessor control unit. The frame is made of aluminum, plastic or zinc-coated pipe. An independent claim is also included for a method for aligning a solar module with respect to condition of the sun.

Description

The invention relates to a tracking device for aligning a solar module with respect to the state of the sun with a module mast and arranged on the module mast solar module. The invention further relates to a method for aligning a solar module with respect to the sun.

Photovoltaic systems are used regularly to convert solar energy into electrical energy. Such photovoltaic systems usually consist of several solar modules which are mounted, for example, on rooftops.

The efficiency of such systems depends, among other things, on the orientation of the solar modules to the position of the sun. For this reason, for example, in Germany solar modules are preferably mounted on roofs with southern exposure.

In order to further increase the efficiency of photovoltaic systems, it may also be provided to track the individual solar modules to the level of the sun which changes during the course of the day. Usually, such devices are used in very large photovoltaic systems, which are composed of a plurality of photovoltaic units. A photovoltaic unit can accommodate one or more solar modules. The photovoltaic units are constructed so that the orientation of the solar modules arranged on the photovoltaic units is adjustable. Usually, the solar modules are mounted rotatably mounted on a permanently connected to the ground module mast. The rotation of the individual modules is then carried out with the aid of suitable drive devices as a function of, for example, the time of day or a measured light incidence intensity. Due to the necessary firm connection with the ground, a quick assembly and disassembly of the individual photovoltaic units is not possible. Therefore, the use of the sun tracked photovoltaic units is usually limited to the use of very large photovoltaic systems.

The object of the invention is therefore to provide a photovoltaic system with improved efficiency.

This object is achieved in that the tracking device has at least one measuring device for detecting a power generated by the solar module. In this way, it becomes possible to align the solar module not only by the time of day or the light intensity of the incident solar radiation, but by the output electric power. This can also be, for example, a measuring device for detecting the electrical charging currents. In this way, the time of day during the alignment can be taken into account.

Advantageously, it is provided that the solar module is received by a fixable on the module mast frame. In this way, it is possible to easily replace defective solar modules and to use solar modules with different dimensions without complex adjustment of the overall system.

Advantageously, the frame is made of aluminum, plastic or galvanized pipe. The use of such weather-resistant and cost-effective materials reduces the manufacturing and maintenance costs.

According to the invention it is further provided that a plurality of solar modules are received by a frame. In this way it is possible to adjust the size of the photovoltaic units.

Advantageously, it is further provided that the tracking device has a gear motor, by means of which the module mast can be set in rotary motion. The alignment of the solar modules usually takes place comparatively slowly. For example, the solar modules are rotated during a day in a period of 8-10 hours the state of the sun from sunrise in the east to sunset in the west by about 270 °. The torque required depends in particular on the mass of the module mast, the frame and the solar modules. Frequently come as a drive device electric motors used. Small, lightweight electric motors usually have very high speeds and thereby bring comparatively low torques. By a gear reduction and very light electric motors can be used as a drive device.

According to a further advantageous development of the subject invention, it is provided that the solar module or a frame is pivotally mounted on the module mast, so that the standing angle of the at least one solar module is adjustable to the sun. The efficiency of the solar modules depends as explained from the angle of incidence of solar radiation on the solar module surface. In addition to the ability to track the solar modules by rotation about their vertical axis the state of the sun, it is therefore expedient to be able to adjust the angle of the solar modules with respect to the module mast. In this way, among other things, a mobile photovoltaic unit can be adapted, for example, to the particular conditions at the installation site.

Advantageously, it is further provided that a Kabelaufrollvorrichtung is attached to the module mast. By means of this cable retractor, the cables, for example, from the solar module to a control device on the module mast, are unwound or unwound during a rotary movement of the module mast. In this way, the length of the cable is constantly adjusted to the cable length required by the current orientation of the solar module. On error-prone sliding contacts can be completely eliminated.

According to the invention it is also provided that a position detection device is arranged on the module mast. With the help of this position detection device, for example, the vertical orientation of the solar module can be determined. The position detecting device may be, for example, a positional disc rigidly connected to the mast with raised cams and electromagnetic proximity switches. Based on the information of such a position sensor, the position control methods used for tracking can be further improved.

To determine the pivoting range of the solar module is further provided that at least one final rotation angle of the module mast can be predetermined by at least one limit switch. By specifying a final rotation angle, for example, the destruction of the cable leading from the solar module to the cable reeling device can be prevented by a faulty control program. However, it is also possible to take into account existing objects which limit the pivoting range at the respective installation site when determining an admissible pivoting range.

For further processing of the various sensor information, it is provided according to the invention that the tracking device has at least one data acquisition device and one central microprocessor control unit, wherein the at least one data acquisition device is in communication with the central microprocessor control unit. The data acquisition device, for example, converts the sensor signals from the various sensors into digital electronic values. The microprocessor control unit processes the sensor signals detected by the data acquisition device and converted into digital electronic values and controls the alignment of the module mast. For this purpose, the microprocessor control unit is designed, for example, such that, in response to a corresponding software command, a control signal is sent, for example, to an electric motor driving the module mast.

Advantageously, it is provided that a photosensor is mounted on the frame or on the module mast or on the data acquisition device. For example, to enable automated tracking, it is necessary to be able to differentiate day by night. Among other things, for this purpose, the use of a photo sensor offers. In order to use the information from the photo sensor for further control tasks, it is useful to attach the photo sensor to the frame of the photovoltaic units. In this way, the intensity of the solar radiation incident on the solar modules can be determined very accurately.

For automatic alignment of the solar modules with respect to the state of the sun, a method is provided in addition to the described tracking device. This method meets the object stated at the outset to allow the largest possible electric power output of the solar modules by appropriate alignment of the same.

This object is achieved by the inventive method for aligning a solar module with respect to the sun, that a first power value is detected at a first position of the module mast, the module mast is rotated by a predetermined angle to a second position, a second power value is detected, the first and second power values are compared and, depending on the comparison result, the module mast remains at the second position when the second power value is greater than the first power value and the module mast is rotated back to the first position when the second power value is less than or equal to the first power value Power value is. By comparing two power output values of the solar module at two different positions can be easily determined which of the two verified positions which is more advantageous in terms of power output at the moment. Repeated execution of these method steps also ensures that the module mast is regularly aligned with respect to the current state of the sun of the solar module or modules, so that the highest possible output of the solar module can be achieved.

Advantageously, it is provided that the power and / or position and / or brightness is detected by an electronic data acquisition device. For processing the power values detected by sensors or other information detected by sensors, it is expedient to detect the sensor signals provided by the sensors and to transmit them to a uniform representation. Usually, the variables measured by the sensors are provided by analog voltage or current signals or pulse-width-modulated voltage or current signals or digitally, for example, on Profibus or CAN data bus systems. The data acquisition device converts these sensor signals, for example, into digital electronic values, which can then be processed uniformly.

According to the invention, it is further provided that a geared motor is controlled by a central microprocessor control unit. The processing of the detected sensor values, for example the comparison of two power values which were detected at two different positions of the module mast, is advantageously carried out on a microprocessor control unit. It makes sense to send from this microprocessor control unit from the control commands to a, the module mast driving, geared motor.

According to the invention, it is further provided that the second power value is detected after an adjustable period of time after detection of the first power value.

According to the invention, it is further provided that the detection of the power values begins when an upper brightness value is reached. In this way, the method for controlling the photovoltaic unit can be started automatically at dawn.

Advantageously, the detection of the power values begins at a final rotation angle. The automated activation of the solar modules should begin at dawn. It is expedient to align the solar module at the beginning of the day as possible in the direction of the sun. For example, to simplify the control, the angle of rotation associated with this mast position can be defined as the final angle of rotation.

According to the invention, it is further provided that when the value falls below a lower brightness value, the detection of the power values is terminated. In darkness, the solar modules provide no electrical energy and the execution of the method described above is usefully stopped in this case.

Advantageously, the module mast is rotated when falling below a lower brightness value to one of the final rotation angle. The lower brightness value expediently indicates the brightness value that is expected to be measured at night. In this case, the solar module can not be provided with electrical energy until the next morning. Therefore, it is expedient to align the module mast already at night to the expected next morning sun position. This position is characterized by a final rotation angle.

A modification of the inventive concept provides that the module mast is rotated in a predeterminable direction when a lower brightness value is exceeded and an upper brightness value is undershot at a predeterminable speed. Experience has shown that there are hardly any differences in performance at different positions of the module mast in heavily clouded skies. In this case, it is expedient for the solar module to track the position of the sun at a predeterminable speed.

Further details of the invention are described in the drawings with reference to the schematically illustrated embodiments.

It shows:

1 a schematic spatial representation of a photovoltaic unit,

2a a sectional view of in 1 shown photovoltaic unit along the line AA,

2 B schematically an enlarged view of the lower portion of in 2a illustrated sectional view,

3 an enlarged schematic representation of a module mast,

4 a sectional view of in 2a shown photovoltaic unit along the line BB on a module mast stand,

5a a schematic representation of the structure of a frame,

5b a detailed schematic view of an upper module holder,

6 a schematic representation of the electrical interconnection of a photovoltaic unit,

7 a flowchart that reflects the basic procedure and

8th a more detailed flow chart for power-dependent control of a photovoltaic device.

1 shows a schematic spatial representation of a photovoltaic device. This photovoltaic unit consists essentially of a frame with solar module 1 Using an upper module bracket 2 and a lower adjustable module bracket 3 on a module mast 4 is attached. The module mast 4 is inside the mast bearing housing 5 mounted rotatably mounted. This construction is in this embodiment by a profile stand cross 6 stabilized. The figure also shows a from the module mast 4 leading to the solar module cable 7 , With the help of the lower adjustable module holder 3 the angle of attack of the frame with respect to the module mast can be adjusted. Since this photovoltaic unit alone by the Profilstandkreuz 6 stabilized, this unit can be easily placed without creating a foundation at almost any location.

2a shows a sectional view of the in 1 shown photovoltaic unit along the line AA and 2 B schematically an enlarged view of the lower portion of in 2a illustrated sectional view. By this embodiment is clear, as with the help of the lower adjustable module holder 3 and the upper rotatably mounted module holder 2 the angle of attack of the frame with solar modules 1 regarding the module mast 4 can be changed. The module mast 4 is in the self-aligning ball bearing 8th mounted rotatably mounted. The self-aligning ball bearing 8th is with the profile stand cross 6 connected. The module mast is stabilized by the mast support ball bearings 9 , The rotational movement of the module mast 4 is in this embodiment via a toothed belt 10 that of a geared motor 11 is driven generated. Instead of a toothed belt is also a drive chain or via a DC gear motor driven worm gear into consideration. On the module mast 4 is also a position detection device 12 attached, with the above the position sensor 13 the position of the module mast can be determined. Inside the mast bearing housing 5 is also the cable retractor 14 shown schematically. The profile stand cross 6 is with adjustable feet 15 equipped to ensure the stability of the photovoltaic unit, even on uneven terrain.

3 shows an enlarged view of a module mast 4 with an upper module holder 2 , the cable winder 14 , the gear 12 , a timing belt pulley 16 and the self-aligning ball bearing 8th , Shown are also two cable post feedthrough holes 17 , Through these holes 17 becomes the cable 7 from the solar module through the module mast 4 in the cable winder 14 guided. There, the cable is rolled up or down depending on the required length.

In 4 is a sectional view of the in 2a shown photovoltaic unit along the line BB shown. The profile stand cross 6 is with the lower housing plate 18 connected. The mast support ball bearings 9 Beyond the ball bearing holder 19 of the housing 5 against housing construction profiles 20 supported. With the help of the four mast support ball bearings 9 becomes the module mast 4 stabilized.

In 5a a frame for receiving solar modules is shown. On the middle strut of the frame 21 is a photosensitive photosensor 22 arranged. On both sides of the strut with photosensitive photosensor 22 can solar modules on the frame 21 to be placed. By the arrangement of the photosensitive photosensor 22 in the middle between the solar modules, not shown, it is ensured that the light intensity acting on the solar modules from the photosensitive photosensor 22 can be detected very accurately.

In 5b is a detailed schematic view of an upper module holder 2 shown. Through the upper module holder 2 Can the frame with solar module 1 pivotally mounted with the module mast 4 get connected.

In 6 schematically an electrical or digital electronic circuit arrangement for a photovoltaic unit is shown. The electrical energy generated by the solar module is via a charge controller 23 in a battery 24 fed. In order to be able to detect the electrical power generated by the solar module with the aid of a data acquisition device, the associated output signal is generated with the aid of the analog measured value converter 25 first in a for the data acquisition device of the programmable logic controller 26 permissible value range changed. On the programmable logic controller 26 the control program for controlling the drive unit runs down. In addition to the power values provided by the solar module, the data acquisition device of the programmable logic controller 26 also by the position sensor 13 detected position of the position detection device 12 fixed to the module mast 4 connected, recorded.

In 7 the main idea of the control program is shown in a simplified flow chart. It is assumed that the module mast is in any position. Starting from this position will be in step 27 recorded a first measured value. Subsequently, in step 28 Waited for a first predetermined period of time. In step 29 the module mast is turned to a second position. After in step 30 the expiration of a second predetermined period of time has been waited, is in step 31 recorded a second measured value. Subsequently, in step 32 the first and second measured values compared. Starting from the comparison result thus obtained is in step 33 the corresponding control command sent to the drive unit. If the power measurement value at the second position exceeds the power measurement value at the first, then the module mast remains at this position; if the second measured value falls below the first, the module mast is turned back to the first position.

In 7 a detailed flowchart for a program flow is shown. Starting from switching on the system by an operator 34 First, it is checked whether the module mast is in an angle range permissible for the start of the program 35 , If this is the case, the program is started. In this embodiment, it is assumed that the program is started in the morning so that the sun is in the east. The module mast should therefore be at the morning's final turning angle. In this embodiment, this Enddrehwinkel is designated position East. First, it is checked whether the module mast is at the final rotation angle east 36 , If this is the case, it is checked whether the light intensity exceeds an upper limit 37 , If this is the case, then a first timer is started with a predefinable period of time 38 , One second before the end of the first timer, the current power value delivered by the solar module is recorded 39 , Subsequently, the module mast is turned over a predeterminable angle in the direction of west 40 , The position of the module mast is detected by the position sensor 42 , Has the module mast reached the predetermined angular position 43 , a second power value of the solar module is detected after one second 39 , Then the performance values are compared 44 , Based on this comparison, there are now two program execution options. If the first power value is greater than the second power value 45 so a second timer is started. After the time period specified in this timer, the module mast is rotated back to the first position 47 , Starting from this position, the program described then runs until the power values are compared 44 again. Appears when comparing the performance values 44 out that the power value measured at the second position exceeds the power value measured at the first position 46 , so the process steps from the current mast position from step 37 repeated. This program sequence is repeated until the module mast has rotated to a second final angle of rotation. Usually, the solar module is oriented at this second final rotation angle to the west, since the sun is in the evening in the west. Below that of the photosensitive photosensor 22 measured light intensity is a lower limit, the module mast is turned back to the first final rotation angle and the program is terminated 48 , An advantage of the described program sequence is that the performance measured values used for comparison are recorded at a time interval of only a few seconds. As a result, the influence of passing cloud fields on the comparison result can be neglected. It will also be appreciated that the described program flow may simply be extended to the comparison of more than two performance measurements acquired at different times and / or at different positions of the module tower. Just as easily, the described program flow can be extended in the event that the photosensitive sensor 22 detected light intensity value is between the lower limit and the upper limit. This can be the case, for example, when the sun is obscured by a closed cloud cover. Experience has shown that in this case the performance values differ only slightly at different positions. Therefore, it is expedient in this case to rotate the module mast with a predeterminable speed from east to west until the upper limit is exceeded and the normal program sequence can continue or the lower limit value is exceeded and the program sequence is terminated.

LIST OF REFERENCE NUMBERS

1

Frame with solar module

2

upper module holder

3

lower, adjustable module holder

4

mast module

5

Mast bearing housing

6

Profile Stand Cross

7

electric wire

8th

Aligning ball bearings

9

Mast support bearings

10

Timing belt, pulley or gear

11

gearmotor

12

Position detection device

13

position sensor

14

cable reeling

15

adjustable feet

16

Timing pulley

17

Cable mast guide bores

18

lower housing plate

19

Bearing retainer

20

Housing construction profiles

21

frame

22

photosensor

23

charge controller

24

battery

25

Analog transducer

26

programmable logic controller

27

Acquisition of a first measured value

28

Waiting for a first predetermined period of time

29

Turning the module mast to a second position

30

Waiting for a second predetermined period of time

31

Acquisition of a second measured value

32

Comparison of the first and second measured value

33

Transmission of the comparison-dependent control command to the drive unit

34

Switching on the system by an operator

35

Check whether the module mast is in an angle range permissible for the start of the program

36

Check if the module mast is at the end rotation angle East

37

Check if the light intensity exceeds an upper limit

38

Start of a first timer with a predefined time span

39

Recording the current performance value

40

Rotation of the module mast towards the west over a predeterminable angle

42

Detecting the position of the module mast

43

Check whether the module mast has reached the specified angular position

44

Comparison of the performance values

45

Query whether the first performance value is greater than the second performance value

46

Inquiring whether the power value measured at the second position exceeds the power value measured at the first position

47

Rotation of the module mast back to first position

48

End of the program

Claims (17)

Tracking device for aligning a solar module with respect to the state of the sun with a rotatably mounted about its vertical axis module mast and arranged on the module mast solar module, characterized in that the tracking device has at least one measuring device for detecting a power generated by the solar module. Tracking device according to claim 1, characterized in that the tracking device comprises a geared motor ( 11 ), by means of which the module mast ( 4 ) can be set in rotary motion. Tracking device according to one of the preceding claims, characterized in that the solar module or a frame ( 21 ) pivotable on the module mast ( 4 ), so that the standing angle of the at least one solar module is adjustable to the sun. Tracking device according to one of the preceding claims, characterized in that a cable reeling device ( 14 ) is attached to the module mast. Tracking device according to one of the preceding claims, characterized in that a position recognition device ( 12 . 13 ) on the module mast ( 4 ) is arranged. Tracking device according to one of the preceding claims, characterized in that at least one final angle of rotation of the module mast ( 4 ) can be predetermined by at least one limit switch. Tracking device according to one of the preceding claims, characterized in that the tracking device comprises at least one data acquisition device ( 26 ) and a central microprocessor control unit, wherein the at least one data acquisition device ( 26 ) is in communication with the central microprocessor control unit. Tracking device according to one of the preceding claims, characterized in that a photosensor ( 22 ) on the frame ( 21 ) or on the module mast ( 4 ) or at the data acquisition device ( 26 ) is attached. Method for aligning a solar module with respect to the sun, characterized in that a first power value at a first position of the module mast ( 4 ), the module mast ( 4 ) is rotated by a predeterminable angle to a second position, a second power value is detected, the first and second power values are compared and, depending on the comparison result of the module mast ( 4 ) remains at the second position when the second power value is greater than the first power value, and the module mast ( 4 ) is rotated back to the first position when the second power value is less than or equal to the first power value. A method according to claim 9, characterized in that the power and / or position and / or brightness by a data acquisition device ( 26 ) is detected. Method according to claim 9 or claim 10, characterized in that a geared motor ( 11 ) by a central microprocessor control unit ( 26 ) is driven. Method according to one of claims 9 to 11, characterized in that the second power value is detected after an adjustable period of time after detecting the first power value. Method according to one of Claims 9 to 12, characterized in that the detection of the power values begins when an upper brightness value is reached. Method according to one of claims 9 to 13, characterized in that the detection of the power values begins at a final rotation angle. Method according to one of claims 9 to 14, characterized in that falls below a lower brightness value, the detection of the power values is terminated. Method according to one of claims 9 to 15, characterized in that the module mast ( 4 ) is rotated to a final rotation angle when falling below a lower brightness value. Method according to one of claims 11 to 16, characterized in that the module mast ( 4 ) is rotated in a predeterminable direction when a lower brightness value is exceeded and falls below an upper brightness value at a predeterminable speed.

Images