DE102018103740A1 - Arrangement of solar elements and method for interconnecting solar elements - Google Patents

Abstract

Arrangement of a plurality of solar elements with a plurality of switches, wherein the switches can interconnect the solar elements into different electrical arrangements dynamically during operation in various ways and a method for interconnecting solar elements with switches, wherein a shading or a difference in performance between different solar elements is detected and the Solar elements are classified into different groups according to their current performance or currently possible maximum power or the current lighting condition and the solar elements of each group are switched together.

Description

The present invention relates to the energy management of an arrangement of solar elements, in particular a solar system and the thermal management of system components such as junction boxes in solar systems and in general a concept for interconnecting voltage-limited power sources.

Series switching of solar cells lead to problems with partial shading, as a shaded solar cell block the flow of electricity of others and thereby can take damage.

Since these processes occur dynamically during operation, a rigid interconnection of the solar cells, as in the prior art, is problematic.

The presented dynamic interconnection is a further development of lessons from the pamphlets DE102011055754A1 and WO2012163908A2 ,

Bypass diodes designed to protect single cells or cell strands work much like a switch. In an integrated form, the z. B. known as a cool bypass switch.

Dynamic interconnection can solve other problems that are named in the prior art. These include protection for firefighters, as in the JP2014068509 (A) as well as a performance limitation as in the US 2015155818 A1 , The problem of the so-called thermal runaways (thermal runaway with self-destruction) of bypass diodes is in the EP1970965A1 pointed.

Starting from the prior art, the invention has for its object to design an electrical circuit concept, which avoids the disadvantages of the prior art listed above.

This object is achieved by an arrangement of a plurality of solar elements with a plurality of switches, wherein the switches can interconnect the solar elements in different electrical arrangements dynamically during operation in various ways.

Thus, a dynamic interconnection concept is proposed, which performs an adaptation of the interconnection of solar elements in operation depending on the shading situation or power output of the solar elements.

In particular, the object is achieved by a solar cell arrangement comprising a plurality of solar elements, a plurality of switches for producing and interrupting electrical connections between the solar elements and a control unit, wherein the control unit is set up to interconnect the solar elements into different electrical arrangements by means of the switches, in particular dynamically during the Operation of the solar elements in different electrical arrangements interconnect.

A solar element is a photo power source. The solar elements preferably comprise individual solar cells, groups of solar cells and / or solar modules. A solar cell preferably includes a photodiode so as to provide electrical energy. A solar cell is preferably a photoelectric current source, particularly preferably a photodiode in the photoelement operating mode. A solar cell preferably has a semiconductor junction, preferably a silicon semiconductor junction, with properties dependent on the irradiation light. The solar cell can have at least two electrical connections, from which a generator current dependent on the irradiation light can be removed. A group of solar cells or a group of solar cells is a number of solar cells, which is either fixed (then referred to as strand or string) or dynamically (then referred to as a group) interconnected and can be controlled as a solar element. A solar cell group is preferably assigned a bypass diode (it provides an additional current path for photo currents that are not covered by the dynamic interconnection of the solar cell groups). A solar module is an assembly of prefabricated solar cell groups or strings. All of these solar elements may be at the same level, i. Solar cells with each other, solar cell groups or strings with each other or solar modules with each other, or at different levels, i. Solar cells with solar groups or strings and / or solar modules or solar cell groups with solar modules or on the same level, i. Solar cells with solar cells, solar cell strings with solar cell strings, solar cell groups with solar cell groups and solar modules are interconnected with solar modules.

This makes it possible to summarize the solar elements, which have a similar shading and in this way an optimized interconnection of solar elements can be made with similar current characteristics.

The solar elements in their dynamic interconnection then together form a solar generator, which can switch the individual solar elements in parallel or in series and thus temporally variable depending on the shading situation can optimize the current efficiency with simultaneous protection against overload.

The control unit has the control logic for the switches. The control unit preferably comprises a microcontroller or microprocessor. By means of the control unit, it is preferably possible by means of at least some of the switches to interconnect at least some of the solar elements into different different electrical arrangements during operation of the solar elements in at least two different ways.

The switches are preferably electrically and / or electronically and / or optically and / or electromagnetically controllable - preferably wire / cable-bound - switches (units). The actuators of the switches are preferably relay contacts, drain-source paths of (MOS) FET or C-E paths of bipolar transistors. Preferably, other switches such as electromechanical switches (relays) or magnetic switches (transducers) are provided. Preferably, the switches are controlled by the electronic control unit several times and switchable several times (switchable, off).

The various electrical arrangements include a series connection, a parallel connection or a combination of series and parallel connection (group circuit), so that some solar elements are connected in series with each other and thus form a solar element group and other solar elements can be connected in parallel to this group. Preferably, in this case, solar elements of approximately or as much as possible the same current are connected in series, preferably when the current intensity of the individual solar elements differ by not more than 10% from each other. Solar elements are preferably connected in parallel, if the output voltage of the different solar elements is as equal as possible, preferably not more than 10% differ from each other.

If unequal solar elements are connected in parallel with respect to the voltage, the result is equalizing currents which can reduce the efficiency of the solar generator and irreversibly damage it depending on the size of the currents. If different solar elements are connected in series with respect to the current intensity, then a part of the solar elements blocks and can thereby take irreversible damage. Therefore, preferably solar elements with the same temperature, the same efficiency and also the same lighting are selected by the control unit dynamically belonging to a group and interconnected together.

Preferably, the interconnection of the solar elements takes place locally, whereby a high degree of freedom for the consideration of different shading scenarios for individual solar elements is achieved. Particularly preferred may be provided an interconnection of solar elements, which is set up for expected shading scenarios, i. that the interconnection of solar elements is preconfigured according to the expected shading scenarios. The dynamic interconnection is therefore preferably constructed according to the most frequently occurring shading types. As a result, switches are saved compared with a local connection.

The technical disadvantages of the prior art solar systems, which must be compensated by downstream electronics (i.e., output side) in the prior art, can be avoided by the present invention. Due to the variable electrical interconnection of the solar elements, the current output is optimized on the input side and not on the output side. In addition, the optional features in the prior art such as emergency shutdown, intrinsic safety and AC output are already formed on the input side and no longer as an output side add-on.

Particularly preferably, an n × m topology can be selected and individual solar elements can be freely configured with each other. If a concrete shading can be predicted on the basis of the specific application, the solar elements can be preconfigured in the geometry to be expected and subdivided along the shading boundaries into solar elements or solar strings in order to perform an interconnection of these solar elements thus formed. As a result, can be dispensed with overhead for a completely free interconnection and unnecessary switching elements for this specific application of shading can be saved.

Preferably, the switches comprise transistors and / or MOSFETs and / or power MOSFETs.

MOSFETs are metal oxide semiconductor field effect transistors and power MOSFETs are a specialized version of a MOSFET optimized for conducting and blocking large electrical currents and voltages (up to several hundred amperes and up to about 1000V, at a component volume of about one cubic centimeter).

Switching is preferably also possible in the current-supplying operating state of the arrangement, so that too high a voltage at the switches / FETs up to approximately 2000 V can be avoided, which would otherwise lead to high RDSon (switch-on resistances) and power losses when using high-voltage MOSFETs ,

Preferably, the control unit comprises a microprocessor and is arranged to switch the switches so that the electrical arrangement has a plurality of power levels, ie buses, to which the solar elements are switched depending on their current power output.

In this way, it is possible to summarize the solar elements according to their power / power yields and switch on a bus that corresponds to this power / output.

• Unverschattete Solarelemente
• Vollverschattete Solarelemente und
• Teilverschattete Solarelemente entlang einer Schattenkante

The solar power of the solar elements is proportional to the lighting. Solar modules can be shaded by nearby objects. These often have straight edges, so the shadows also have straight edges. In the simple case, one can form three classes of shading:

• Unshaded solar elements
• Fully shaded solar elements and
• Partially shaded solar elements along a shadow edge

• High: 100% Strom = unverschattet
• Low: 30% Strom aufgrund der diffusen Hintergrundstrahlung mit 30% Anteil bei Vollverschattung
• Mid: 65±30% Strom durch eine Beleuchtung entlang einer Schattenkante

Thus, preferably a division into three power buses is made:

• High: 100% power = not shaded
• Low: 30% current due to the diffuse background radiation with 30% share with full shading
• Mid: 65 ± 30% current through lighting along a shadow edge

Thus, in a group may be an equal number of solar elements, it may also be a different number of solar elements, if they have a different level. Preferably, N-power buses are combined into a power bus.

A solar cell arrangement preferably comprises a connection for an intermediate consumer, preferably an inverter or a converter. About this connection, such an intermediate consumer can be connected.

Preferably, an impedance converter is provided as an intermediate consumer with controllable or adjustable or self-adjusting optimum impedance as a function of the (average) impedance of the source (s), especially according to the MPPT method (Maximum Power Point Tracking).

Further preferably, an operation of the solar generator is provided as an inverter, which acts as a DC-AC / AV converter and converts the DC photoelectric current of the solar generator into AC voltage. Particularly preferred in this case is an inverter operating mode is used, with which an AC bus with center frequencies of at least 50 kHz, preferably from 100 kHz, can be generated. Thus, in case of accident of the solar element, for example contact after an accident, the current flow through the skin and not through the heart. Preferably - so that the usual 50Hz output voltage inverters can be used according to the prior art for power supply - connected before the input of these inverters a rectifier that provides the usual in the prior art direct current for the 50Hz inverter. A preferred embodiment is an active rectifier which has the advantage of higher efficiency over bridge rectifiers. Active rectifiers consist of transistor switches (NMOS) with suitable control unit and replace in their function the diodes of the bridge rectifier.

In a further embodiment, the solar generator in dynamic interconnection 50Hz AC in the mode "isolated operation" (feeding into a power island) deliver, while above a possible "network operation" (feed into the public grid) is described.

In a further exemplary embodiment of the solar cell arrangement, the solar elements are arranged in an m × n, in particular a 2 × 2 or 3 × 3 topology, and the switches are arranged such that n solar elements can be connected in series with one m × n topology and thus one Form strand. Preferably, a bypass diode is connected in parallel with each of the n strings. Preferably, quadratic topologies are used so that m = n.

To be able to switch solar element groups in parallel, they must have the same voltage and therefore the same number of cells. With ideal power sources, the number of cells is negligible, but solar cells are power sources with intrinsic diodes connected in parallel. Therefore, a parallel connection of different numbers of solar cells can lead to equalization currents and thus to the loss of yield, i. to reduce the efficiency. Therefore, a division of the solar elements or solar cells in n × n groups is preferred because it can be built n equal long cell strands or groups that can be connected in parallel without disadvantage. In order to cover error cases in the circuit, each of these n cell strands is preferably connected in parallel with a bypass diode in each case.

Preferably, a fourth diode is connected via the input and output of the electrical two-pole of the solar element. This reduces the diode losses. As a result, the current flow through ensures the solar element at any time of dynamic interconnection, including during switching.

In a further embodiment, the switches are arranged so that the solar elements in the horizontal direction, in the vertical direction, in diagonal orientation or corner can be interconnected in groups. It is thus possible, for example, to group the solar elements in a row, in a column, in the diagonals or the solar elements arranged at a corner into groups in a square arrangement of solar elements arranged in columns and rows. Preferably, an equal number of solar elements are always connected together in each case a group, so that when selecting the diagonal and parallel diagonals are combined into one group. For example, with a 3x3 matrix with the elements 1.1 to 3.3, it is possible to form three groups with diagonal alignment, namely the middle diagonal consisting of the three individual elements 1.1, 2.2 and 3.3 and the respectively adjacent solar elements 2.1, 3.1 and 3.2 and 1.2, 1.3 and 2.3. Also, the orthogonal division is conceivable, i. 1.1, 1.2, 2.1 / 1.3.2.2, 3.1 / 2.3.3.2.3.3. With an alignment over corner or an angular orientation, it is possible to form two groups of four solar elements, for example, the solar elements 1.1, 1.2, 2.1, 2.2 and 1.3, 2.3, 3.1, 3.2, 3.3. Particularly preferred is a cell from the group with five cells left uncontacted to avoid unwanted balancing currents in a parallel circuit of 4 + 5 cells and thus to have two groups of four groups in a parallel circuit. In the case of horizontal alignment, the three rows are grouped together (1.1, 1.2, 1.3 / 2.1, 2.2, 2.3 / 3.1, 3.2, 3.3) and in vertical alignment the three columns (1.1, 2.1, 3.1 / 1.2, 2.2, 3.2 / 1.3 , 2.3,3.3). This is correspondingly feasible for smaller or larger square arrangements.

In a further embodiment, the switches are arranged so that some or all groups can be interconnected in parallel. If the groups consist of an equal number of solar elements that are similarly shadowed, they have the same maximum output current and are therefore similar. This allows the individual solar elements to be connected in series to form a group. If the output voltage of the different groups of solar elements is the same, they can be switched in parallel. It is thus possible, for example, in the case of vertical shading of the first two columns 1 and 2 to switch the groups of the first column and the second column in parallel, and then these two in series to the third (not shaded) group.

The object is also achieved by a method for the dynamic interconnection of solar elements with switches via a control unit, wherein a shading or a power difference between different solar elements ( 20 ) is detected, for. B. by a measurement using MPPT, the solar elements are classified into different groups according to their current performance or currently possible maximum power or the current lighting condition and the solar elements of each group are interconnected. Through this dynamic interconnection of the solar elements during operation groups can be identified on similar solar elements and interconnected so that the individual solar elements take no damage and the overall arrangement of the solar elements has a high efficiency.

• Unverschattete Solarelemente
• Vollverschattete Solarelemente und
• Teilverschattete Solarelemente entlang einer Schattenkante

Specifically, it is possible, for example, to make a shading-adapted selection of solar cells or solar elements by defining a plurality of current classes / buses. Arrangements of solar elements may be shaded by objects in the environment. These often have straight edges, so the shadows also have straight edges. If you look at a partially shaded arrangement of solar elements, then you see

• Unshaded solar elements
• Fully shaded solar elements and
• Partially shaded solar elements along a shadow edge

• High: 100% Strom = unverschattet
• Low: 30% Strom aufgrund der diffusen Hintergrundstrahlung mit 30% Anteil bei Vollverschattung
• Mid: 65±30% Strom durch eine Beleuchtung entlang einer Schattenkante

Since the solar power of the cells is proportional to the illumination, a division into three power buses is preferably carried out:

• High: 100% power = not shaded
• Low: 30% current due to the diffuse background radiation with 30% share with full shading
• Mid: 65 ± 30% current through lighting along a shadow edge

If the electrical interconnection runs parallel to a shadow edge, the power loss is lower than if the interconnection is perpendicular to it. In this case, a straight shadow affects all solar elements, even if they are only partially shaded. Therefore, it is preferably provided to combine the solar elements in groups of similar solar elements and then interconnect, so that the highest possible efficiency of the arrangement of solar elements is achieved.

Preferably, the rigid electrical circuitry of the environment is adapted by arranging the arrangement of solar elements or solar modules preferably horizontally or vertically. However, even if the environment preferably produces vertically aligned shadow edges, in winter you have snowboards on the solar modules that produce horizontal shadow edges. The power output in winter is by no means low, since the solar modules are cold and have a high efficiency and the radiation can occur despite the cold with high radiation intensity. Therefore, a decision for a direction of interconnection (= geometric orientation of the solar modules) is always only occasionally optimal. By the claimed method, a solution is provided to achieve an optimized interconnection of the solar elements in these scenarios and thus on the one hand to protect the individual solar elements from damage and on the other hand to increase the efficiency of the arrangement of solar elements.

• Horizontal
• Vertikal
• Diagonal
• Diagonal um 90° gedreht (orthogonal)
• Winkelförmig bzw. über Eck

For example, the expected shading alignments by buildings are:

• Horizontal
• Vertical
• Diagonal
• Diagonally rotated by 90 ° (orthogonal)
• Angular or over corner

A dynamic interconnection is effected by a spatial combination of solar elements, in particular of solar cells, according to the geometrical shading orientation just outlined. The geometric division of the cell matrix is always as parallel as possible to a shadow edge. This is the strategy for cell division horizontally, vertically, diagonally, orthogonally. The geometrical divisions just listed are optimal for shading with straight and parallel shadow edges. Angular shadings, however, have two mutually orthogonal shadow edges. These are preferably split up like diagonal shadows to keep the directional selection of cells simple. In the case of angled shading, it is preferable to carry out a nonlocal division into three power buses, and for the electrical interconnection to electronically convert the power sources into voltage sources by means of three MPPT carried out.

Preferably, a circuit summary of the three power buses in one with downstream MPPT respectively. This method is used to make a single dipole from the three current buses high, medium, low, ie the three dipoles (H, M, L bus) consisting of the interconnected strands as an example. This is done by optional series connection S1 + S2 + S3 parallel connection S1∥S2∥S3 group circuit Version 1: S1 + (S2∥S3) Variant 2: S2 + (S1∥S3) Variant 3: S3 + (S1∥S2)

In this way, a method is provided with the individual solar elements in an array of solar elements, preferably using MPPT interconnected so that the individual solar elements are estimated from irreversible damage, in particular by series connection of different current with respect to the solar elements and on the other hand, the efficiency the arrangement of solar elements is increased.

Preferably, the solar elements of a group are connected in series, more preferably, some or all groups are connected in parallel.

• - wechselweises Umschalten der Polarität der gesamten Anordnung von Solarelementen, geeignet dazu einen Wechselstrom zu generieren;
• - Generierung einer Wechselspannung größer 50 Hz, insbesondere 300 kHz;
• - Herstellung der Spannungsfreiheit der gesamten Anordnung der Solarelemente nach außen, d.h. eine Notabschaltung;
• - Notabschaltung bei Temperaturüberschreitung einer Temperaturüberwachung wenigstens eines der Solarelemente, insbesondere für den Brandschutz.

Particularly preferably, the solar elements will be switched so that at least one of the following functions is realized:

• - alternately switching the polarity of the entire array of solar elements, capable of generating an alternating current;
• - Generating an AC voltage greater than 50 Hz, in particular 300 kHz;
• - Making the voltage free of the entire arrangement of the solar elements to the outside, ie an emergency shutdown;
• - Emergency shutdown at temperature exceeding a temperature monitoring at least one of the solar elements, in particular for fire protection.

• - Monitoring von Betriebszustand, Strom, Spannung, Temperatur oder Hardwarecheck wenigstens eines der Solarelemente und der Elektronik für die dynamische Verschaltung (Selbstcheck);
• - Realisierung eines SMART-Moduls mit einer Menge an Solarelementen, die ein Modul bilden;
• - Lichtbogenerkennung und Modulabschaltung;
• - Diebstahlschutz und Standorterkennung;
• - Überwachung der Überschreitung der Betriebstemperatur und Einleitung von Blitzschutzmaßnahmen;
• - Optische und/oder akustische Kenntlichmachung, wenn das Modul defekt ist.

Preferably, a set of the solar elements form a module and a microcontroller or programmable microprocessor realizes at least one of the following functions:

• Monitoring of operating status, current, voltage, temperature or hardware check of at least one of the solar elements and the electronics for the dynamic interconnection (self-check);
• Realization of a SMART module with a set of solar elements forming a module;
• - Arc detection and module shutdown;
• - theft protection and location detection;
• - Monitoring of excess temperature and initiation of lightning protection measures;
• - Visual and / or acoustic identification, if the module is defective.

Embodiments of the invention are explained below with reference to the drawings.

• 1 ein Solarzellenstring mit Bypassdiode,
• 2 ein Solarmodul mit 3 Solarzellenstrings mit Bypassdioden,
• 3 Schaltsymbol und Ersatzschaltbild einer Solarzelle,
• 4 eine Leistungs- und Spannungskurve eines teilverschatteten Moduls,
• 5 eine Leistungs- und Spannungskurve eines unverschatteten Moduls,
• 6 einen Solargenerator mit parallel geschalteten Solarzellenstrings, davon ein String elektrisch verkürzt
• 7 die Arbeitspunkte für einen Rückstrom unter und ohne Last,
• 8 eine Solaranlage mit einer seriellen Diode pro Solarzellenstring,
• 9 eine Gruppenschaltung,
• 10 eine Solarzellenanordnung mit weiteren Dioden,
• 11 Solarmodule in Serienschaltung nach dem Stand der Technik,
• 12 eine dynamische Serienschaltung von Solarzellen mit gleichem Maximalstrom und Aufteilung in 3 unterschiedliche Stromniveaus,
• 13 ein Solarmodul mit Zusammenfassung der 3 Strombusse von 12 in einen Strombus durch MPPT
• 14 eine Reihenschaltung von Solarmodulen von der Art von 13
• 15 eine starre Reihenschaltung von Solarmodulen mit MPPTs nach dem Stand der Technik,
• 16 eine horizontale Abschattung mit dynamischer Verschaltung, mit Bypassdioden in Dickmannschaltung siehe US Patent No. 6225793 Serial No. 09545328 17 einen Schaltplan für eine Simulation einer Reihenschaltung,
• 18 ein Beispiel für eine zeitliche Abfolge einer Abschattung,
• 19 die Abfolge der Abschattung vergrößert,
• 20 eine Leistungskurve einer 3x3 Solarzellgruppe,
• 21 eine Leistungskurve einer 3x3 Solarzellgruppe orthogonal,
• 22 ein Beispiel für eine vertikale Verschattung,
• 23 ein Beispiel für eine diagonale Verschattung,
• 23a Stromgruppen für die diagonale Verschattung,
• 23b Stromgruppen für eine orthogonale diagonale Verschattung,
• 24 ein Beispiel für eine winkelförmige Verschattung,
• 25 MOS-Schalter,
• 26 ein Verschaltungskonzept für die dynamische Verschaltung.

Show it:

• 1 a solar cell string with bypass diode,
• 2 a solar module with 3 solar cell strings with bypass diodes,
• 3 Switching symbol and equivalent circuit of a solar cell,
• 4 a power and voltage curve of a partially shaded module,
• 5 a power and voltage curve of an unshaded module,
• 6 a solar generator with parallel solar cell strings, of which one string is electrically shortened
• 7 the operating points for a return current under and without load,
• 8th a solar system with one serial diode per solar cell string,
• 9 a group circuit,
• 10 a solar cell arrangement with further diodes,
• 11 Solar modules in series connection according to the prior art,
• 12 a dynamic series connection of solar cells with the same maximum current and division into 3 different current levels,
• 13 a solar module with summary of the 3 power buses of 12 into a power bus through MPPT
• 14 a series connection of solar modules of the type of 13
• 15 a rigid series connection of solar modules with MPPTs according to the prior art,
• 16 a horizontal shading with dynamic interconnection, with bypass diodes in Dickmann circuit see US Pat. 6225793 Serial No. 09545328 17 a circuit diagram for a simulation of a series circuit,
• 18 an example of a temporal sequence of shading,
• 19 enlarges the sequence of shading,
• 20 a power curve of a 3x3 Solar cell group,
• 21 a power curve of a 3x3 Solar cell group orthogonal,
• 22 an example of a vertical shading,
• 23 an example of a diagonal shading,
• 23a Current groups for the diagonal shading,
• 23b Current groups for orthogonal diagonal shading,
• 24 an example of an angular shading,
• 25 MOS switches,
• 26 An interconnection concept for the dynamic interconnection.

Solar modules according to the prior art are designed for ideal installation in a solar system. This includes the lack of shading, a homogeneous orientation in one direction and sufficient ventilation. If this is not the case, then significant yield losses and electrical and thermal stress for the plant.

In freestanding solar systems, the lighting situation can be improved by mechanically tracking the solar cells or solar modules with so-called trackers. In solar modules, which are attached to the building (BAPV Building Attached Photovoltaics such as rooftop systems and also BIPV Building Integrated Photovoltaics such as solar façades) is not or only with difficulty possible. When mounting on a building envelope, shadowing is to be expected already for geometric reasons (projections, bay windows, chimneys, antennas, etc.). According to the state of the art, shadowed parts of the building envelope are therefore often left out. This problem is inventively solved in that instead of the mechanical tracking a concept of electrical tracking of the system is presented. Thus, moving and thus error-prone parts can be avoided.

The present presentation focuses on crystalline solar cells, where the situation is the most problematic due to the high currents.

Solar modules consist of a series connection of solar cells. Solar cells are not voltage but current sources. A solar cell provides a proportional to the light irradiation electricity. Ideal power sources have an infinitely high output voltage

According to the usual rules of electrical engineering one would have to switch power sources in parallel. However, because the solar cells only have a low real output voltage of about 0.6V at the maximum power point (MPP), they are still connected in series (as a string) to achieve technically usable input voltages. The output voltage of such a series circuit of solar cells may currently be up to 1500 VDC. The same applies to individual solar modules, which are often connected in series, in order to deliver a voltage that an inverter can usefully convert to a grid-suitable alternating voltage.

Is a solar cell in this series - consisting of z. 2,000 solar cells - shaded, this not only supplies a small amount of power, but worse, it also blocks the large current flow of the remaining unshaded solar cells. It breaks down rather than yielding to the flow of electricity. This is an essential feature of power sources. However, the output voltage of the unshaded cells is large enough to force the current through the shadowed cell. In order to protect the shadowed solar cell from self-destruction, bypass diodes are inserted in sections in the series connection, which conducts the "excess" current around the shaded solar cell.

Such a section of a solar cell string ( SZS ) designated arrangement of solar cells, consisting of an electrical series circuit of 20 solar cells SC is in 1 shown. On the right in the circuit diagram is the bypass diode D1 ,

SZS according to the prior art consist of 20 or 24 Solar cells. When the solar cells are connected in series, the best technical solution with regard to energy yield is to provide each solar cell with a bypass diode. However, to lower the purchase price of the solar module, but SZS used with a bypass diode ( 1 ). The shaded cell sees in the bypass case, the voltage of all remaining solar cells of the SZS plus the forward voltage of the bypass diode. The number of solar cells in one SZS is therefore limited by the blocking voltage of the solar cells used. Solar modules made of crystalline solar cells therefore exist z. B. from 3 SZS with 3x20 = 60 or 3x24 = 72 cells.

2 (Source: wdwd - Own work, CC-BY-SA 4.0 .
https://commons.wikimedia.org/w/index.php?curid=39303681) shows a solar module consisting of three solar cell strings SZS ( PC1 . PC2 . PC3 ). in a standard solar module. The middle one SZS ( PC2 ) is shaded and the electricity I therefore flows through the bypass diode D2 ,

From a fire protection point of view, solar cells are a source of danger: Solar cells or modules are sources of ignition, because electrical energy is flowing through them, and at the same time they carry the fuel in the form of their organic content in the form of embedding and reverse side foils. They are approved according to electrotechnical standards and usually - due to the usually untested residual capacity and fire class - they have no general construction supervisory approval. This complicates the technical approval as a solar façade or solar roof with integrated solar modules (BIPV)

The electrical characteristic of a solar cell can be obtained by electrical equivalent circuit diagrams. There are more or less detailed equivalent circuits for a solar cell. For the basic understanding, the simplest of all equivalent circuit diagrams, as in 3 (Source: From Degreen from the German Wikipedia, CC BY-SA 3.0 , https://commons.wikimedia.org/w/index.php?curid=7724909). The circuit symbol is shown on the left and the equivalent circuit consists of a light-controlled current source and a diode for limiting the voltage. As a result, an illuminated solar cell shuts off its own photocurrent while idling. The output voltage of the solar cell corresponds to the forward voltage US of the diode.

For partial shading, as in 4 Although the bypass diode results in a large power loss in the solar module, the solar cells (power sources) are connected in series and not in parallel. It is the power curve P (MPP) and voltage curve U (MPP) for the situation 2 shown. The maximum power is removed from the solar module if the lighting-dependent maximum current of the shaded solar module group PC2 is removed. Increasing the load current through the load resistor RL, then the output voltage and thus the power drops significantly. For the short-circuit currents of the solar cell groups PC1 and PC3 9A was adopted and for the shadowed solar cell group PC2 30% of 9A. Due to the diffuse background radiation of about 30% light intensity, the current of PC2 not to zero.

In comparison shows 5 the voltage and power curve of the unshaded solar module. Again, the power curve P (MPP) and voltage curve U (MPP) are for the unshaded solar module according to FIG 2 shown.

It turns out that the maximum power in 4 only 30% of the unshaded maximum power 5 is, although only one SZS ( PC2 ) is shadowed. It can therefore be stated: The loss of yield due to shading can be considerable despite the bypass diode, even if only one cell (resp. SZS ) is shadowed. Without calculation, only by eye one may be tempted to assume that the output power is still approximately between 66% and 77% of the maximum power, which corresponds to the proportion of the proportion of "failed" solar cells. In reality, however, the bill gives only about 34% of the maximum power.

The cause of the strong drop in partial shading yield is the rigid electrical series connection of the solar cells within the solar modules and increasing with the current voltage drop at the bypass diode D2 in 2 and the voltage drop across the electrical wiring of the solar module.

The bypass diodes can be located in the solar junction boxes, which are firmly bonded to the solar module. Due to the waste heat concept of the solar junction boxes according to the approval standards EN 50548 and EN 61730, a so-called thermal runaway of the bypass diodes can occur because the temperature dependence of the diode reverse current is not considered and only with the EN 62979 standard : 2016 attracted attention.

After a thermal runaway, the bypass diode is broken or defective. In case of interruption and partial shading, the affected cell group can then be irreversibly destroyed.

In the event of a short-circuiting defect of the bypass diode and partial shading, it depends on the operating situation whether the junction box with the defective bypass diode is thermally overloaded. The short circuit of the damaged bypass diode is not perfect and often produces the triple waste heat of an undamaged diode in bypass mode.

6 (Source: SMA http://files.sma.de/dl/7418/Rueckstrom-UEN083010.pdf) shows a solar generator, consisting of parallel SMS (solar module strings), which are connected to an inverter (right). Operation takes place with a short-circuiting bypass diode.

During operation, the inverter will remove the solar module strings (SMS) current at full voltage, as in 7 shown, so that in the shortened by the short electrically shortened SMS flows relatively little. However, if the inverter is switched off, then a significant compensation current flows in the form of reverse current in the solar system, which can not be switched off according to the prior art without additional electronics (solar module string diode). The inverter is partly interconnected by the grid operator of the public power grid. The solar power supplier has no influence in this case.

In 7 the operating points reverse current with load (operating point OP1 => Irev = 9A) and no load (operating point OP2 => Irev = 27A) are shown.

In particular, when the solar system is a solar façade, a short circuit of modules in the event of an accident is conceivable (eg in the case of a crash of a car with the solar façade). The flow of equalizing currents can make rescue operations difficult or impossible as long as the sun is shining.

Such errors can be met with string diodes, as in 8th , which is a solar system with one string diode per string, is shown.

However, string diodes cause energy loss during normal operation of the system because they are warming up and it is not certain if their function is monitored in practice. Ie. they can fail to conduct and the failure is hardly recognized during normal operation by a slight reduction in the output of the system. In the event of a conductive failure, the solar system continues to supply power, but increased heat dissipation of the string diode, which could be detected, for example, by temperature monitoring of the string diode and no interruption of current, which is easily recognizable by the power breakdown of the solar system. For the sake of cost savings, string diodes are not always installed.

Another potential failure in solar systems is the failure of solar connectors and also the loss of cable isolation due to marten bite. With this error, an arc can form which burns for a long time (about 30 minutes) and does not go out. In the US, such situations are encountered with the use of arc detectors, which are mandated by NEC 2014 (National Electric Code 2014 and following). At present, there are hardly any arc detectors in Europe.

DC arcs do not go out as easily as AC arcs because of the lack of voltage zero crossing. Therefore, a solar module with AC output has advantages in this regard.

The type of cable routing within the solar modules results in an area in which voltages can be induced by magnetic fields. In nature, such magnetic fields are generated by lightning near field impacts, which can then damage the bypass diodes and other parts of the system. Following errors can then be arcs in the solar system, when the sun shines again.

In the following an electrical circuit concept is proposed, which the o.g. Disadvantages avoids or represents a less expensive solution than existing systems.

Depending on the lighting situation of the solar modules, the circuit concept switches dynamically adapted series, parallel and group switching of the solar cells within a solar module and generally also of solar modules within solar generators as well as in general the connection of voltage-limited current sources.

This means solar cells, which are connected in series at one time, can be switched dynamically and switched in parallel at a different time. Likewise vice versa and possibly optional for more than two solar cells. The latter allows dynamic group switching.

The term solar element includes here as the smallest unit a solar cell. Alternatively, it may also be meant a dynamically and electrically linked group of solar cells, the z. B. form a solar module. Also a solar module, which consists of several strands, or groupings of strands and solar cells, can form a solar element. Statements that are therefore made for solar cells or modules are i.d.R. also valid for the other element. The electrical connection can, but does not have to be done by electrical or electronic switches. Magnetic linkage using transformers with multiple windings and also with the help of transducers is just as conceivable in addition to other physical effects. Thus, solar cells, as well as solar modules, can be interconnected with the switch arrangement described by way of example below.

Accordingly, such a switch arrangement, for. As in a solar module, a plurality of electrical switches that can electrically connect each individual solar cell with other solar cells or solar cell groups in series, in parallel or in a group circuit. Each solar module consists of a lot of solar cells. In the dynamic interconnection, subsets are formed from this total quantity, which do not have to be geometrically close. These subsets are interconnected in series, parallel and group switching depending on the lighting so that the maximum energy can be taken from the solar module. At the same time, this reduces the energy loss in the bypass diodes and thus lowers the operating temperature of the junction boxes.

In 9 (Source: Source: http://elektrotechnik-fachwissen.de/grundlagen/gruppenschaltung.php) is a combination of series connection (left) and parallel circuit (right), which is called group circuit shown.

This concept may not be as optimized in terms of yield as a bypass diode per solar cell, but the ability to provide additional functionalities such as self-diagnostic AC modules, integrated solar panel shutdown, and dormant solar panels through the large number of switches makes the use of electronics (Switch assembly) again attractive.

A preferred technical solution for the switching elements are semiconductor switches.

These solar cell groups are preferably connected together so that the current flow is not hindered by shaded cells and thus little or no current flows through the bypass diode. This reduces the electrical and thus in particular thermal stress for the system and increases the current yield compared to a rigid electrical connection with bypass diodes.

10 (Source: WO2012163908A2 . 5 ) shows the use of additional diodes as a semiconductor switch through which less solar cells are bridged than usual during shading.

An embodiment of the proposed electrical interconnection concept provides completely free interconnectability of solar cells / elements in all possible combinations. This would require a lot of switches.

In the following, an interconnection concept with more than one current level (power bus line) is presented.

11 shows a solar module according to the prior art. Voltage sources in electronic devices often have lines with different voltage levels (voltage levels), which in the present case are also referred to as buses. Accordingly, one can also build different power bus lines in circuits with power sources. Solar modules according to the prior art have only one power bus, as in 11 shown in the out of 20 or 24 solar cells (power sources) in series a solar cell string 26.1 to 26.6 ( SZS ) is formed. The solar cell string 26.i , which is indicated by the dashed circle in the figure, consists of 20 solar cells connected in series and a diode. Since the solar cells all, even with the same illumination, have a slightly different output current, bypass elements are D1 to D6 (Bypass diodes or Smart Bypass Diodes), which compensate for the output current difference.

A preferred concept is to dynamically interconnect the solar cells such that a solar module has a plurality of current outputs. The solar cells are divided into groups of power, which depending on the lighting have a high current (H-Bus), a medium current (M-Bus) and a low current (L-Bus).

12 shows such a model of a solar module with dynamically interconnected solar cells, which in three power bus lines H . M and L (High, Mid, Low) are split. The bus lines lead to an inverter 40 with three independent inputs It is preferable to use three separate inverters or one inverter with three separate inputs. Since the efficiency of an inverter is input current dependent, it is preferred for each current group H . M and L a specially optimized inverter used. The solar module 27.1 or. 27.2 works in this interconnection as a power source.

This would have a solar module 27.1 or. 27.2 this type 6 Connecting cables. This is not optimal due to a very complex wiring that is prone to error during installation (cable mess, mating error, especially if many switches are required).

In 13 an arrangement is shown in which the number of connecting leads is reduced to 2 pieces by interposing electrical energy converters. The remedy is to place the bus lines each on a DC / DC converter whose output is a voltage source. These converters, each on the solar panel 27 can then be easily connected in series. These DC / DC converters must be able to automatically find the optimum operating point of the solar cells. These types of transducers are called MPP trackers. ( MPPT or Maximum Power Point Tracker) and turn the power source solar module into a voltage source. 13 shows the model of a solar module 27.1 with dynamic interconnection. The currents are applied to three power bus lines ( H1 . M1 . L1 ) divided within the module. The dotted circle shows the solar element group 25 on the power bus line H1 shown. Accordingly, the solar element groups are constructed on the other power bus lines. Each of these lines has its own Maximum Power Point Tracker ( MPPT H . MPPT-M . MPPT-L ). The output of these trackers, which are connected in series, makes this solar module 27.1 a voltage source. Even with rigid electrical wiring, the application of MPPT on the modules to a higher power output of the solar system compared to the standard circuit in 11 , With a dynamic interconnection like in 13 This yield can be further increased.

In addition, as in 14 shown several such solar modules 27.1 and 27.2 according to 13 (possibly dynamically) interconnected, z. In series. Since the outputs form voltage sources, a series connection of voltage sources is shown here.

There are preferably three concepts for the dynamic interconnection: 1) conversion of current sources into voltage sources by electronics (im MPPT implicitly executed and in 14 2) Distribution of the current sources into equal current intensities eg High, Mid, Low and 3) Combining the current sources in only one power bus after the in 16 described method.

Commercially available modules are already supplied interconnected and are not configurable. This means that the interconnection of the SZS firmly wired in series in the solar module. The possibilities for an interconnection according to the above figures would be better if connection options were freely accessible.

Such modules can nevertheless, as in 15 shown to be connected with MPPTs. Rigid in series connected modules can thus when using MPPT be connected in series.

With dynamic interconnection, the fineness of the subdivision into different power buses can be arbitrarily resolved. Each power bus needs one MPPT because the number of cells in a power bus group varies depending on the lighting and the bus voltage is different and variable. Each solar cell can be connected in series to one of the power buses. With complete freedom of choice for the connection to power buses, the number of required switches or MPPTs is high.

Therefore, it is proposed as an additional improvement that, in order to save MPPTs, the power buses and also the solar cells within the solar module in addition to the series connection in parallel and group circuits are interconnected.

As a result, you only need one more MPPT per solar module. In this extreme case, the solar module would become the power source again. If one waives the DC / DC converter at the module output, strings of solar modules with dynamically interconnected solar cells can no longer be parallel be switched because their output voltage varies depending on the lighting. Preferably, the dynamic interconnection of solar modules within the solar system is therefore carried out analogously to the dynamic cell interconnection.

The number of switches required can be reduced by restricting to suitable interconnection options for the most common shading geometries. The disadvantage of this is that you lose some performance over the optimal solution.

In the following, an interconnection concept with only one current level (power bus line) is presented.

16 describes the method and the interconnection geometry for concept 3 ), ie summary of the 3 power buses High, Mid Low in only one common power bus. In the following it is worked out, how many solar cell elements one wants to connect together as a group. The number of switches and control complexity increases with the number.

The number of switches can be reduced by grouping the solar cell elements within a solar module into small groups. These groups may be an n × n cell matrix, in the simplest case a 2 × 2 cell matrix. Other embodiments are conceivable. As an example, the wiring concept is explained on a 3 × 3 cell matrix. A large number of these 3 × 3 cell matrices then form a solar module.

Other implementations of quadratic (n × n; n element of natural numbers) or rectangular (n × m; n and m element of natural numbers) cell matrices are conceivable.

The 3 × 3 cell matrix has the special feature that it can be connected in three vertical, three horizontal or optionally also in three diagonal series circuits (strings), which each time have the same number of solar cells and thus the same solar cell string voltage. This facilitates the parallel connection and group switching of these cells within the cell matrix. The solar cells are interconnected so that their geometric arrangement runs parallel to a shadow edge. As a result, a classification is introduced, which represents a practice-relevant approximation.

The types of interconnection may be for a 3x3 cell matrix as in 16 can be seen for a horizontal course of shading, ie a migrating in the vertical direction shadow. On the left is the shaded image of the solar cell matrix, on the right the dynamically selected interconnection for the respective shading situation (a) to (e).

In an unshaded state (shading situation a), the 3 horizontally arranged strands 26.1 . 26.2 and 26.3 connected in series, on the one hand not to hinder the flow of current (keep bypass diodes as de-energized and minimize waste heat), and on the other hand to generate the highest possible voltage.

• Schritt 1: Den maximalen Strom der am besten beschienenen Solarzellen ermitteln. Diese kommen in die Reihenschaltung (Linker Teil der Gruppenschaltung gemäß 16)
• Schritt 2: Die restlichen Zellen parallel verschalten, damit die Summe der Teilströme möglichst hoch wird.
• Schritt 3: Sind alle Zellen in der Gruppe „gleichmäßig“ beschienen, aus allen eine Reihenschaltung bilden. Die Zellen gelten als „gleichmäßig“ beschienen, wenn sie eine Stromabweichung von weniger als 30%, bevorzugt von weniger als 20%, insbesondere bevorzugt von weniger als 10% vom Maximalstrom aufweisen.

For this purpose, the following method is preferably used:

• step 1 : Determine the maximum current of the best-lighted solar cells. These come in series connection (left part of the group circuit according to 16 )
• step 2 : Interconnect the remaining cells in parallel so that the sum of the partial currents becomes as high as possible.
• step 3 : If all cells in the group are "evenly lit", they all form a series circuit. The cells are considered to be "even" when they have a current deviation of less than 30%, preferably less than 20%, most preferably less than 10% of the maximum current.

In the shading situation (b) in which the first strand 26.3 is partially shaded, this is another strand (here 26.2 ) connected in parallel and forms together with the strand connected in series 26.1 a group circuit, so no destructive current through the teilververschatteten strand 26.3 is forced.

In the shading situation (c), in which the second strand 26.2 Partially shaded, both partial shaded strands 26.2 and 26.3 connected in parallel. In the example, there is no more dynamic switching between the circuit for the shading situation (b) and the shading situation (c), since the setpoint connection according to the shading situation (b) already exists.

Preferably, with a freedom of choice of the interconnection, as in the shading situation (b) or (c), assumptions can be made about the future shading in order to perform the parallel connection of the strands, which would also be favorable in a subsequent shading situation.

In the shading situation (d), if the shadow has covered the whole module and continues to shade unevenly, then the same rule applies to the interconnection as described in scenarios (b) and (c).

In a next step, when the shadow has fully and uniformly detected the module (shading situation (s)), the strands can be switched back into series or parallel from the standpoint of non-destructive freedom; in 16 a parallel connection is shown. Advantageously, a pure parallel connection of the strands takes place at low power, so that the least possible current flows through the bypass diodes, see 4 and 5 , When a bypass current occurs, it means a large power loss.

To recognize is off 16 in that always illuminated (or powerful) solar cells are combined as equally as possible. In the example shown, the solar cells can always be combined in a horizontal direction due to the horizontal shadow line. In this case, no switches needed to be able to separate and connect 3 horizontal strands of the solar cells. The geometric division of the cell matrix is preferably carried out as parallel as possible to a shadow edge. This is the strategy for cell division horizontally, vertically, diagonally, orthogonally. The geometrical divisions just listed are optimal for shading with a shadow edge. Angled shadows have 2 shadow edges. These are split like diagonal shadows to keep the directional selection of cells simple. This division is not optimal for angular shadows.

This concept can be transferred to all larger units, so matrices of solar modules (instead of individual solar cells) can be interconnected in this way.

In the following, a proof of the possible energy increase by the dynamic interconnection concept by simulation calculations is presented.

In order to prove the usability of the proposed interconnection method, a simulation model is set up. It consists of three groups of three solar cells each, which are interconnected in series, parallel and group circuit. The model simulates a horizontal or a vertical shading of a 3 × 3 solar cell group by way of example.

17 shows a circuit diagram for the simulation in the special case of series connection. V1-V4, B1 and V6 generate auxiliary variables for the calculation, which are needed for later finding the power maximum at each time. They are intended for numerical simulation.

The drawn bypass diodes D4 . D10 and D14 over the cell matrix can be replaced by a switch which operates by a controller as if it were a diode. In integrated form this is referred to as Cool Bypass Switch, which can also be built discretely.

For the bypass elements different trade names exist, eg. B. "Cool Bypass Switch", "Smart Bypass Diode" or "Ideal Bypass Diode". This refers to a NMOS with charge pump and controller in a housing. This can alternatively be replaced by a MOS switch.

A shading sequence with a temporal offset is introduced into the model, which shadows the three solar cell groups following a time course S1 . S2 and S3 simulates how in 18 shown in a temporal sequence of shading in a fictional solar system. A section of the diagram 18 is in 19 shown. The shadow is almost a solar cell wide.

In 20 In the case of a partial shading parallel to the long axis of the module, the power of the unshaded 3 × 3 solar cell group is shown in series connection as a solid line. The dotted line shows the series connected solar cell group with temporally continuous partial shading. The power drops off 176 Watt up 149 Watt off. This corresponds to the state of the art. By group switching at appropriate times, the performance on 156 Watts are raised. This corresponds to a power increase of 0.77 watts per cell. The parallel connection of the solar cells brings here no increase in performance. Drawn through is the unshaded plant in series.

If the solar module has been mounted rotated by 90 ° with the same shadow geometry, then all three will be SZS simultaneously shadowed. This situation is in 21 and shows the performance of the 3 × 3 solar cells when the solar module is mounted perpendicular to the shadow edge. In this case, the solid line, the power output at full illumination, the dotted the power output of the module in series connection of the cell groups and the dotted line shows the power output with parallel connection of the cell groups.

When shading occurs, the performance of 176 Watt down to 96 watts. Through a parallel connection of the three cell groups, the performance can 110 Watt be increased. This corresponds to an increase in performance of more than 1.5 Watts per cell. The time-dependent optima are in 20 displayed.

An odd number of groups / strings would be unfavorable if there is an antiserial circuit of the matrices such that zero U, ie no voltage, is present from the module. An antiserial circuit is when you connect two voltage sources with the same pole. This results in a two pole with zero voltage. This connection makes sense if you want to achieve that the output voltage is zero volts. This is a sensible way to switch off a solar system. But it is also due to short circuit and interruption of the solar cells, the short circuit after DIN VDE AR2100-712 only on short notice.

Preferably, the number of solar cells per matrix strand is the same, because otherwise a current flow preferably takes place in the shorter strand, which would lead to equalization currents and power loss.

In the following, more categorizations of the shading types occurring in practice are listed (in addition to shading by a horizontal shadow line). When restricted to certain categories, switches can be saved.

The electrical wiring concept of vertically shaded cell matrix, as in 22 shown corresponds to the wiring concept shown above with horizontal shading in a different orientation. This will be in 22 shown that a vertical shading can be treated electrically as the horizontal shading.

Another special case is diagonal shaded cell groups, as in 23 shown. 23 leads a diagonal shading in a horizontal shading by the solar cells according to 23a in turn, according to the method according to 16 be dynamically interconnected. In diagonal shading, the cells of a 3 × 3 cell matrix as in 23a and 23b shown in power groups I1 to I3 summarized. 23a shows the performance groups for a shading process according to 23 (third picture). 23b shows the power groups for a shading process in the orthogonal direction, from bottom left to top right and thus treated by 90 ° rotated diagonal shading and leads them electrically into a horizontal shading over. These power / power groups are linked in series, in parallel or in group as shown above.

Angular shaded cell matrices, as in 24 are shown as diagonal shaded cells in the same geometry divided into three groups. The downside is wasted performance. Optimally, solar cells are grouped according to their lighting. Since the diagonal diagonal circuit is optimized for diagonal shading, you give away power at angle-shaded. However, the gain is still higher than in the prior art rigid interconnect, see 20 , Treated with it 24 the angular shading and converts them into a diagonal shading according to the 23a or 23b over and thus electrically again in a horizontal shading according to 16 ,

A large number of cell matrices are interconnected to form a solar module and the principle of the dynamically interconnected solar cells can be applied analogously to these cell matrices. The principle of dynamic interconnection can also be applied to the solar modules as a higher-level cell matrix in a solar system. As already mentioned, the term solar element can comprise both on the solar cell level and on the solar module level.

The division of the solar cells into n × n cell matrices has an influence on the number of solar cells in a solar module. When divided into 3x3 = 9 cells, a number of 72 = 8x9 cells is preferred. When divided into 2 x 2 cells, a number of 15 x 4 = 60 cells is preferred. 60 and 72 cells are the usual number of cells in standard modules.

Example becomes in 26 for a 3 × 3 cell matrix, a SPICE model showing the dynamic interconnect but not the process concept of 16 includes. On the left side of the block diagram are 3 bypass diodes (the fourth is missing), a Rangierverteilung which realizes the series, parallel and group circuit, as well as a Polwender for anti-parallel, separation or alternation.

The pole turner allows the solar element to be completely isolated (i.e., turned off), thereby producing an intrinsically safe solar module that provides power only after the previous enable signal. Solar systems can be completely switched off. This is also new compared to the prior art, which accomplishes this interconnection by additional electronics.

Furthermore, solar elements can thus be switched together in such a way that they remain electrically conductive, but do not deliver any output voltage because they compensate each other (anti-serial connection).

The Polwender can also be used for the generation of alternating current. An alternating current with a frequency of more than 100kHz significantly reduces the risk of muscle cramps and cardiac arrest / atrial fibrillation.

In the middle of 26 is the geometric selection of the solar cells from the exemplary 3 × 3 cell matrix for the division into horizontal, vertical, diagonal and 90 ° -twisted diagonally (orthogonal).

25 is an incomplete section of the required intermediate circuits or shunting distributors within the 3 × 3 cell group 26 and contains a small part of the switches.

Due to the optional communication (enable signal) and the power optimization method, the overall circuit preferably has a microprocessor which can interconnect the 8 pieces of 3 × 3 cell matrices horizontally, vertically, diagonally, 90 ° turned diagonally and also angularly. This is called Smart Module. By default, the solar system can be rigidly interconnected with smart modules. Preferably, a dynamic interconnection of the solar modules is provided, which can be connected horizontally, vertically, diagonally, diagonally 90 ° twisted, angle-shaped or block-shaped as needed.

• Solarzellen mit gleicher Beleuchtung werden bevorzugt in Gruppen zusammengefasst. Die Gruppen werden bevorzugt parallel verschaltet. Wenn nicht gleich das ganze Modul verschattet ist, dann sind in dieser Betriebsart die Bypasselemente nicht in Betrieb. Optional kann die Ausgangsspannung dynamisch verschalteter Solarmodule durch einen integrierten DC/DC-Wandler auf normales Niveau angehoben werden.

Other variants of the wiring variants described give further advantages:

• Solar cells with the same illumination are preferably grouped together. The groups are preferably connected in parallel. If not the entire module is shadowed, then in this mode, the bypass elements are not in operation. Optionally, the output voltage of dynamically interconnected solar modules can be raised to a normal level by an integrated DC / DC converter.

Due to the dynamic interconnection, the polarity of the solar module can be reversed in stages. As a result, the solar module on its own already supply alternating current. This alternating current can be used to form a DC / DC converter or MPP tracker with a few additional components. Alternatively, the solar cells can be connected so that no voltage is discharged from the solar module to the outside, whereby it is then in a safe resting state. Operation is initiated by external communication. Thus, an intrinsically safe solar module can be realized with integrated emergency shutdown.

An operating mode "AC module" is made possible by corresponding switching of the switches and thereby the generation of an AC voltage / current. The frequency does not necessarily have to be 50 Hz. Increasing the frequency to preferably 300 kHz has the advantages that transformers for voltage separation or transducers can be smaller and therefore cheaper and, when in contact with the system voltage in the event of an accident, the currents flow through the skin and not via the heart (skin effect). , A cramping of muscles would not take place then. As a result, the system voltage for people is less dangerous than conventional systems. Incidentally, the alternating current facilitates an automatic extinguishing of arcs in the event of a fault due to its current zero crossings.

The above-mentioned modes are preferably controlled by a microcontroller or microprocessor. Therefore, with little additional effort, a communication network of solar modules with other advantages is conceivable. If, for example, an external fire occurs, this information can be reported to all modules by temperature monitoring. They can then automatically switch off even before the fire has hit the entire system.

The status of all modules can be reported to a control panel. This can z. As operating condition, current, voltage, temperature, hardware check and optionally include other parameters.

Each solar module can register in the form of a homepage. This is a SMART module in the Internet of Things, which is integrated into the SMART Home feasible.

The microprocessor preferably takes on the task of arc detection and module shutdown.

The microprocessor preferably assumes the function of theft protection and a location message.

The microprocessor preferably monitors the hardware so that it protects itself. This can include the exceeding of a maximum operating temperature as well as lightning protection measures.

The firmware of the processor is preferably kept up to date by updates.

A fault condition is preferably communicated to the outside by corresponding electronic communication or alternatively or additionally also visually or acoustically, so that the search for the faulty module is shortened in large installations.

In this way, an optimized arrangement of solar elements with dynamic interconnection has been provided during the operation of the solar elements as a function of their current performance characteristics and a method for controlling such an arrangement of solar elements.

LIST OF REFERENCE NUMBERS

1

Arrangement of several solar elements

10

Counter ( SW . Sx )

20

solar element

22

solar cell

25

group

26

strand

27

solar module

30

control unit

40

inverter

SC, Sx

Solar cell

D, D1, Dx

(Bypass) diode

SZS, PC _x

solar string

I

electricity

R _L

load resistance

P (MPP)

power curve

U (MPP)

voltage curve

SW, Sx

Switch

MPPT

Maximum power point tracker

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011055754 A1 [0004]
• WO 2012163908 A2 [0004, 0088]
• JP 2014068509A [0006]
• US 2015155818 A1 [0006]
• EP 1970965 A1 [0006]
• US 6225793 [0051]

Cited non-patent literature

• DIN VDE AR2100-712 [0128]

Claims (14)

Solar cell arrangement (1) comprising a plurality of solar elements (20), a plurality of switches (10) for establishing and interrupting electrical connections between the solar elements (20) and a control unit (30), characterized in that the control unit (30) is set up by means of the switches (10). 10) to interconnect the solar elements (20) in different electrical arrangements. Solar cell arrangement (1) according to Claim 1 , characterized in that the control unit (30) is arranged, by means of the switch (10) to interconnect the solar elements (20) dynamically during operation in different electrical arrangements with each other. Solar cell arrangement (1) according to one of the preceding claims, wherein the solar elements (20) comprise individual solar cells, strands of solar cells (26) and / or solar modules (27). Solar cell arrangement (1) according to one of the preceding claims, characterized in that the switches (10) comprise transistors and / or MOSFETs and / or power MOSFETs. A solar cell assembly (1) according to any one of the preceding claims, wherein the control unit (30) is arranged to switch the switches (20) such that the electrical assembly has a plurality of current / power levels to which the solar elements (20) are dependent upon their current current - / power output are switched on. Solar cell arrangement (1) according to one of the preceding claims, further comprising a connection for an intermediate consumer. Solar cell arrangement (1) according to one of the preceding claims, characterized in that the solar elements (20) are arranged in an m × n, in particular a 2 × 2 or 3 × 3 topology and the switches (10) are arranged so that in a m × n topology n solar elements (20) can be connected in series and thus form a group (25). Solar cell arrangement (1) according to one of the preceding claims, characterized in that the switches (10) are arranged so that the solar elements (20) in the horizontal direction, in the vertical direction, in diagonal orientation or corner in groups (25) are interconnected , Solar cell arrangement (1) according to one of Claims 7 or 8th , characterized in that the switches are arranged so that some or all groups (25) are interconnected in parallel. Method for dynamically interconnecting solar elements (20) with switches (10) via a control unit (30), wherein a shading or a difference in performance between different solar elements (20) is detected, the solar elements (20) are classified into different groups according to their current powers or currently possible maximum power or current lighting condition, and the solar elements (20) of each group are interconnected. Method for interconnecting solar elements (20) according to Claim 10 , characterized in that the solar elements (20) of a group (25) are connected in series. Method for interconnecting solar elements (20) according to one of Claims 10 to 11 , characterized in that some or all groups (25) are connected in parallel. Method for interconnecting solar elements (20) according to one of Claims 10 to 12 , characterized in that the solar elements (20) are switched so that at least one of the following functions is realized: - alternately switching the polarity of the entire array of solar elements (20), suitable for generating an alternating current; - Generating an AC voltage greater than 50 Hz, in particular 300 kHz; - Production of the absence of voltage of the entire arrangement of the solar elements (20) to the outside; - Emergency shutdown when temperature exceeds a temperature monitoring at least one of the solar elements (20). Method for interconnecting solar elements (20) according to one of Claims 10 to 13 , characterized in that a set of the solar elements (20) form a module and a microcontroller or programmable microprocessor realizes at least one of the following functions: - Monitoring of operating state, current, voltage, temperature or hardware check at least one of the solar elements (20) including its own Electronics; Realization of a SMART module with a set of solar elements (20) forming a module; - Arc detection and module shutdown; - Theft protection and location detection; - monitoring the exceeding of the operating temperature and initiation of lightning protection measures; - Visual or audible identification if the module is defective.

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