DE102008039320A1 - Solar power plant, has control device for selecting solar module that is adapted to demand of primary useful energy and/or efficiency of solar module and for focusing solar radiation power on selected solar module - Google Patents

Abstract

A concentrating photovoltaic solar power plant (1) with at least one tower structure (2) and with a plurality of heliostats (4) which can be aligned with the tower structure (2) is described. On the tower structure (2) photovoltaic solar cells (10) are arranged and a control device (8) is provided for controlling the alignment of the heliostat (4) on selected solar cells (10) as a function of operating parameters of the solar cells (10).

Description

The The invention relates to a concentrating photovoltaic solar power plant with at least one tower structure and with a plurality of on the Tower construction alignable heliostats.

to Energy production becomes solar energy in different ways used. Here, the photovoltaic is used by photovoltaic Surface elements applied to platforms and optimal be tracked to the sun. The efficiency of such Photovoltaic systems can be increased by concentrator modules where solar radiation is concentrated with mirrors and / or lenses and be directed to special monolithic concentrator solar cells. Thus, the required area of expensive solar cell material be reduced. It is exploited that the photovoltaic concentrator solar cells high efficiency and III-V semiconductor-based solar cell efficiencies of over 37%.

Such photovoltaic concentrator modules consisting of monolithic multilayer concentrator solar cells and this directly associated Fresnel lenses are for example in the DE 10 2006 007 427 A1 described.

The Photovoltaic concentrator solar cells are multi-layered, wherein different wavelengths adsorbing layers be monolithically stacked on a single substrate. This will be the solar spectrum on several solar cells made of semiconductor layers split with different bandgap energy. hereby can be generated by heat generation of hot carriers reduces resulting losses and thus improves the efficiency become. Heat is generated in particular by photons with a Energy generated that is larger than the bandgap is, as well as by transmission of photon with an energy which is smaller than the band gap of the semiconductor used.

In F. Dimroth, A. Bett: "III-V Semiconductor Concentrator Cells" in FVS Themen 2003, pages 48 to 52 the technology of III-V semiconductor concentrator cells is described in detail.

DE 10 2006 058 845 B3 discloses an inverter with integrated control and regulation for a tracker to track a solar generator for the sun, so that it is always aligned to the brightest point in the sky.

When Concentrating solar power plants are also known tower power plants, in which with heliostats solar energy on a tower head arranged steam generating machine is directed. Here is the at the Concentration of solar energy available high temperature exploited, while in the photovoltaic area power plants of the power generating photovoltaic effect used in semiconductor structures becomes.

Such tower power plants are for example in DE 28 52 654 C2 . DE 10 2004 044 841 A1 . DE 102 139 700 B3 . DE 10 2006 053 758 A1 and DE 102 48 068 B4 described.

The energy-converting facilities in the tower head are relatively complex, heavy and require a complex cooling system. hereby The tower must also be large and static be constructed resilient. This leads to relatively high Investment costs.

The require extensive use of concentrating solar cells On the other hand, a relatively complex module design with integrated, trackable Fresnel lenses placed above the concentrator solar cells are attached.

task The present invention is therefore a concentrating solar power plant to improve that it is cheaper and more economical is and has the highest possible efficiency.

The Task is with the concentrating photovoltaic solar power plant the type mentioned above solved that on the Turmbauwerk multilayer photovoltaic concentrator solar cells are arranged and a control device for controlling the Alignment of heliostats to selected solar cells depending on the operating parameters of at least one the solar cell is provided.

According to the Teaching the present invention is thus proposed, the advantages a tower power plant with the advantages of concentrator solar cell modules to unite. It is suggested that the concentration of solar radiation with the help of heliostats aimed at a tower construction wherein, instead of the usual steam-generating generators in the tower now photovoltaic solar cells are arranged.

In contrast to the known concentrating solar power plants, in which the concentrator modules themselves track the sun, in the present concentrating photovoltaic solar power plant, a concentration of the solar cells on a tower structure and the focusing of the sunlight with the help of heliostats in a relatively large distance to the solar cells. This has the advantage that relatively inexpensive heliostat fields can be used which are easy to are controllable. In addition, the installation of solar cells on a tower construction is relatively easy and inexpensive. For the tower construction, the solar cells have the advantage that they are very light, so that the tower structure can be statically simple and inexpensive dimensioned.

Thereby, that the heliostats are flexibly aligned and focused on solar cells it is possible already by appropriate Control of heliostats Hot spots of solar cells to prevent.

The Optimization of the efficiency of the solar power plant is achieved by that the alignment and focusing of the heliostats on selected Solar cells depending on operating parameters of Solar cells is controlled. There is thus a recording of operating parameters the solar cells, such as the over a solar cell or a group of interconnected solar cells resulting electrical Voltage, that of a solar cell or a group interconnected Solar cell flowing electricity or temperature in the area a solar cell or a group thereof. It can takes into account the operating parameters of all solar cells or, preferably, only the operating parameters of a selection scattered on the illuminable surface arranged solar cells or a selection scattered on the surface Groups of solar cells. These operating parameters determine that at least one heliostat generated focal spot of solar energy, the per heliostat on one or more concentrator solar cells is concentrated in dependence of the operating parameters. In this way, on the one hand, overheating of the solar cells avoided and on the other hand, the available solar power be focused on such a number of solar cells that These are operated with optimum efficiency. If necessary then not other solar cells or other groups of solar cells illuminated if the solar power is insufficient.

Advantageous is when the heliostats each have their own drive means for individual Have alignment. This can be a very flexible Controlling the alignment and focusing of the heliostats on the Reach solar cells. It is also conceivable that heliostats to Groups summarized with a drive group associated with a group so that a group of heliostats work together on one or the other several solar cells or groups of solar cells are aligned. Groups of solar cells are preferably connected in series to to generate a sufficient electrical voltage. Several serial interconnected groups of solar cells are in turn connected in parallel, to increase the performance, that is at the Mains voltage to provide sufficient power.

at controlling the alignment and focusing of associated heliostats can be used as operating parameters preferably the operating parameters of each connected in series. This means, that not a single solar cell individually used for control but the operating parameters of a pooled group regardless of how the operating parameters of the individual Solar cells of the group are.

It is particularly advantageous if concentrator solar cells are monolithically joined together on a common wafer and connected together to form at least one group. Several wafers are then interconnected again. The wafers should preferably be hexagonal in order to achieve the best possible area utilization. The photovoltaic concentrator solar cells preferably have an area of up to 20 mm ^2, and more preferably an area of up to 10 mm ² . The area should be in the range of 2 to 10 mm ² .

When Solar cells are preferably multilayer monolithic concentrator solar cells; also Called stacking cells used. By such, based on III-V semiconductor Built-up solar cells can reduce the adsorption spectrum of sunlight be used optimally by reducing thermal losses.

The Solar cells on a tower construction can in addition to the energy production also easy to calibrate the alignment of the heliostat of a heliostat field be used. When relocating a heliostat results in a Change of voltage distribution across the field of solar cells that are comparable to a surface image sensor can be evaluated. A field of individual solar cells can thus also be used as a calibration tool, preferably mobile with associated (image) evaluation algorithms for the heliostat device can be provided.

The Invention is based on an embodiment with the attached drawings explained in more detail. Show it:

1 - Sketch of a concentrating photovoltaic solar power plant with a field of photovoltaic solar cells in a tower construction;

2 - Sketch of a photovoltaic solar cell constructed solar cell array in front view;

3 - Sketch of the solar cell array 2 in the back view with Temperatursen sors.

1 leaves a sketch of a concentrating photovoltaic solar power plant 1 recognize that at least one tower structure 2 and a heliostat field 3 with a plurality of on the upper part of the tower structure 2 alignable heliostat 4 Has. The heliostats 4 Here are individually or collectively in groups on suitable drive means in a conventional manner alignable and focusable.

Solar radiation of the sun 6 This is done by suitable alignment of the heliostats 4 caught and on a field 7 photovoltaic solar cells focused in the upper area of the at least one tower 2 is arranged. Thus, as shown, a single tower structure 2 for a heliostat field 3 be provided. But it is also conceivable several tower structures 2 with respective fields 7 of photovoltaic solar cells for a heliostat field 3 provide, optionally, depending on the available solar energy of one or more of these tower structures 2 supplied so that an optimal energy yield is ensured.

A control device 8th is with the field 7 Photovoltaic solar cells connected to, depending on operating parameters of the solar cells via control lines 9 the individual heliostats 4 or to control groups thereof in order to align and focus them optimally on selected solar cells as a function of the operating parameters. It is prevented by appropriate control that the solar cells overheat and so-called hot spots arise. In addition, by aligning and focusing the heliostat 4 depending on the available solar energy according to the state of the sun 6 be achieved that the photovoltaic solar cells are operated with the best possible efficiency. Thus, to supply the entire solar power plant with insufficient solar energy, the available solar energy can be concentrated on such a number of solar cells that they are optimally illuminated, while another group of solar cells is disregarded and does not contribute to the energy supply to the operating state.

2 leaves a sketch of a field 7 of photovoltaic solar cells 10 detect. Here, a plurality of individual solar cells 8.1 to 8.19 pp. provided individually or as a group by one or more heliostats 4 can be illuminated. Thus, in the sense of a concentrator solar cell module, a heliostat 4 be used to solar energy on one or more solar cells 10 concentrate while other heliostats 4 for lighting other solar cells 10 or other groups thereof are provided.

The solar cells 10 are preferably monolithic, multi-layered concentrator solar cells with semiconductor layers which are stacked on a substrate and adsorb different wavelengths, each of which forms a photovoltaic element. By monitoring the over the individual photovoltaic solar cells 10 or groups thereof resulting electrical voltages or through the solar cells 10 flowing through streams and / or in the region of the individual solar cells 10 or groups thereof, which may vary from solar cell to solar cell, may overheat the solar cells 10 be prevented. For this purpose, the respective heliostats 4 as a function of the aforementioned operating parameters aligned and focused so that the incident on a solar cell solar energy a defined limit, the safe operation of the solar cells 10 guaranteed, does not exceed. In addition, the heliostats 4 depending on the operating parameters aligned and focused so that the solar cells 10 and the entire field 7 of solar cells 10 operated with optimum efficiency.

The field 7 of solar cells 10 also has cooling. For this purpose, the solar cells 10 for example, on a cooling plate 11 are mounted, which is cooled by means of a passage of a cooling fluid and / or by means of air cooling.

3 leaves a backside view of the field 7 of solar cells 10 recognize, while it becomes clear that on the back of the individual solar cells 10 temperature sensors 12 are arranged. The over the individual temperature sensors 12 determined temperatures are then used as operating parameters of the control device 8th fed.

It is conceivable that not each of the solar cells is assigned its own temperature sensor. It can also be groups of solar cells 10 be summarized to with a temperature sensor 12 for such a group, for example, aimed at the center of the group, to determine the temperature of this group of solar cells and to use as operating parameters.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 102006007427 A1 [0003]
• - DE 102006058845 B3 [0006]
• - DE 2852654 C2 [0008]
• DE 102004044841 A1 [0008]
• - DE 102139700 B3 [0008]
• - DE 102006053758 A1 [0008]
• - DE 10248068 B4 [0008]

Cited non-patent literature

• - F. Dimroth, A. Bett: "III-V Semiconductor Concentrator Cells", in FVS Themen 2003, pages 48 to 52 [0005]

Claims (11)

Concentrating photovoltaic solar power plant ( 1 ) with at least one tower structure ( 2 ) and with a plurality of on the tower structure ( 2 ) alignable heliostats, characterized in that on the tower structure ( 4 ) photovoltaic solar cells ( 10 ) are arranged and a control device ( 8th ) for controlling the orientation of the heliostat ( 4 ) on selected solar cells ( 10 ) as a function of operating parameters of at least one of the solar cells ( 10 ) is provided. Concentrating photovoltaic solar power plant ( 1 ) according to claim 1, characterized in that an operating parameter is the electrical voltage of at least one solar cell ( 10 ) or at least one group of interconnected solar cells ( 10 ). Concentrating photovoltaic solar power plant ( 1 ) according to claim 1 or 2, characterized in that an operating parameter of at least one solar cell ( 10 ) or at least one group of interconnected solar cells ( 10 ) is flowing electricity. Concentrating photovoltaic solar power plant ( 1 ) according to one of the preceding claims, characterized in that an operating parameter is the temperature in the region of at least one solar cell ( 10 ) or at least one group of solar cells ( 10 ). Concentrating photovoltaic solar power plant ( 1 ) according to one of the preceding claims, characterized in that the heliostats ( 4 ) each own drive means ( 5 ) for individual orientation. Concentrating photovoltaic solar power plant ( 1 ) according to one of the preceding claims, characterized in that the heliostats ( 4 ) into groups with a drive means assigned to a group ( 5 ), so that a group of heliostats ( 4 ) be aligned together. Concentrating photovoltaic solar power plant ( 1 ) according to one of the preceding claims, characterized in that groups of solar cells ( 10 ) are connected in series and several series-connected group of solar cells ( 10 ) are in turn connected in parallel. Concentrating photovoltaic solar power plant ( 1 ) according to claim 7, characterized in that the operating parameters of a series-connected group each for controlling the alignment of associated heliostat ( 4 ) be used. Concentrating photovoltaic solar power plant ( 1 ) according to one of the preceding claims, characterized in that the photovoltaic concentrator solar cells ( 10 ) each have an area up to 20 mm ² and a plurality of concentrator solar cells ( 10 ) monolithically on a wafer to at least one group of interconnected concentrator solar cells ( 10 ) are summarized. Concentrating photovoltaic solar power plant ( 1 ) according to one of the preceding claims, characterized in that solar cells ( 10 ) are monolayer monolithic concentrator solar cells. Calibration device for heliostats ( 4 ) of concentrating solar power plants, characterized by a field of individual solar cells ( 10 ) and an evaluation unit which is used to determine the orientation of heliostats ( 4 ) as a function of the area distribution of operating parameters, in particular the temperature and / or the voltage and / or the current, of at least one solar cell ( 10 ) or at least one group thereof or the change of area distribution is established.