Photovoltaic converter with selective switch-off in case of an arc event and a photovoltaic assembly comprising such a photovoltaic converter

Abstract

The invention relates to a photovoltaic converter (1) having a plurality of photovoltaic inputs (8) for in each case at least one photovoltaic module (3) or at least one photovoltaic string (4), also called a multi-string photovoltaic converter, and to a photovoltaic assembly (1, 3, 4) having such a photovoltaic converter (1). The photovoltaic converter (1) is equipped with a feed converter (6), a DC voltage intermediate circuit (7), a plurality of photovoltaic inputs (8) for in each case one photovoltaic module (3) or one photovoltaic string (4), an arc detector (12), a plurality of DC / DC converter groups (10) and a control unit (13). The feed converter (6) is designed to draw electrical energy stored in the DC voltage intermediate circuit (7) from said circuit, to invert the drawn stored electrical energy and to feed the inverted electrical energy into a supply network (2). The arc detector (12) is designed to detect the occurrence of an arc event at one of the photovoltaic inputs (8). Each DC / DC converter group (10) contains one or more DC / DC converters (11), wherein each DC / DC converter group (10) is connected between a respective subset of the plurality of photovoltaic inputs (8) and the DC voltage intermediate circuit (7), and is designed to draw a respective PV electrical energy available at the respective subset of the photovoltaic inputs (8) and to feed said PV electrical energy into the DC voltage intermediate circuit (7). The control unit (13) is connected to at least the arc detector (12) and the feed converter (6). According to the invention, the arc detector (12) is also designed to display to the control unit (13), using a signal, the subset of the photovoltaic inputs (8) at which the arc event occurred. Furthermore, the control unit (13) is designed to interrupt the feeding of the PV electrical energy into the DC voltage intermediate circuit (7) at only the displayed subset of the photovoltaic inputs (8) in response to the signal from the arc detector (12).

Description

[0001] 2024P09334 DE

[0002] 1

[0003] Description

[0004] Photovoltaic inverters with selective shutdown in the event of an arc flash and a photovoltaic arrangement with such a photovoltaic inverter

[0005] Technical field

[0006] The invention relates to a photovoltaic converter with a plurality of photovoltaic inputs for each photovoltaic module or photovoltaic string, also called a multi-string photovoltaic converter, and a photovoltaic arrangement with such a photovoltaic converter.

[0007] Technical background

[0008] The generation of renewable energy, for example through photovoltaic systems, plays a crucial role in the fight against climate change. These systems help to reduce dependence on fossil fuels and lower CO2 emissions, contributing to a more sustainable and environmentally friendly energy supply.

[0009] Photovoltaic systems use photovoltaic modules to convert sunlight into electricity. The electricity generated by the photovoltaic modules is direct current (DC). However, since the public power grid requires alternating current (AC), photovoltaic inverters are used to convert the generated direct current into alternating current. This makes it possible to use the generated electricity either directly in the household or to feed it into the public power grid.

[0010] Multiple photovoltaic modules are often connected in series to form strings, increasing the output voltage and improving the efficiency of generating alternating current (AC) for the grid. A multi-string photovoltaic inverter is a special type of inverter used in photovoltaic systems to convert the direct current (DC) generated by multiple independent strings of photovoltaic modules into alternating current (AC).

[0011] The multi-string photovoltaic inverter enables optimized power control for each individual string. This is advantageous because the individual strings can have different electrical characteristics, for example due to different orientations or partial shading. 2024P09334 DE

[0012] 2

[0013] By independently controlling each string, the multi-string photovoltaic inverter can maximize the total power output of the photovoltaic system for a given area of ​​the photovoltaic modules.

[0014] A multi-string photovoltaic inverter has a dedicated photovoltaic input for one or more parallel-connected strings. To enable power extraction at the maximum power point (MPP) for the string(s), a DC / DC converter is provided at each photovoltaic input. This allows power extraction at a voltage different from the DC link voltage. The DC link serves as a buffer for the electrical energy extracted from the photovoltaic modules, which is used by the inverter that performs the actual conversion from direct current to alternating current.

[0015] Electric arcs at the photovoltaic inputs of a photovoltaic inverter pose a serious safety problem. They occur when an electric current flows through the air between two conductors that are not fully connected. This can happen, for example, due to loose connections, damage, contamination, or improper installation. Such arcs can generate high temperatures that can lead to fires. They also cause electrical losses and can damage the components of the photovoltaic system. Furthermore, arcs pose a safety risk to personnel such as maintenance staff.

[0016] Photovoltaic inverters can therefore be equipped with arc flash detectors in accordance with standard IEC 63027. These detectors can detect an arc flash event and, as a result of the detection, trigger a shutdown of the photovoltaic inverter. Maintenance personnel must then travel to the shut-down photovoltaic inverter to rectify the fault so that the photovoltaic inverter can be put back into operation.

[0017] The disadvantages here are the high personnel costs and the fact that the photovoltaic inverter is shut down for the time until the necessary repair.

[0018] The invention aims to introduce an improved photovoltaic inverter. This objective is achieved through a photovoltaic inverter according to claim 1. Advantageous embodiments of the invention are the subject matter of the dependent claims. 2024P09334 DE

[0019] 3

[0020] Summary of the invention

[0021] A first aspect of the invention therefore introduces a photovoltaic inverter equipped with a feed-in inverter, a DC link, a plurality of photovoltaic inputs for at least one photovoltaic module or at least one photovoltaic string, an arc fault detector, a plurality of DC / DC converter groups, and a control unit. The feed-in inverter is configured to extract electrical energy stored in the DC link, convert the extracted stored electrical energy into an alternating current, and feed the converted electrical energy into a power grid. The arc fault detector is configured to detect the occurrence of an arc fault at one of the photovoltaic inputs.Each DC / DC converter group contains one or more DC / DC converters, with each DC / DC converter group connected between a specific subset of the plurality of photovoltaic inputs and the DC link. Each DC / DC converter group is configured to extract the PV electrical energy available at that specific subset of photovoltaic inputs and feed it into the DC link. For example, each DC / DC converter group can contain exactly one DC / DC converter connected between exactly one (two-pole) photovoltaic input and a photovoltaic module or string. In this case, the subset of photovoltaic inputs contains exactly one (two-pole) photovoltaic input. Alternatively, multiple DC / DC converters and multiple photovoltaic inputs can be monitored jointly by the arc detector, so that these multiple DC / DC converters are combined into a DC / DC converter group with multiple DC / DC converters.The control unit is connected to at least the arc detector and the power supply converter.

[0022] According to the invention, the arc detector is also configured to indicate to the control unit, via a signal, the subset of photovoltaic inputs at which the arcing event occurred. Furthermore, the control unit is configured to interrupt, upon receiving the signal from the arc detector, the supply of PV electrical energy to the DC link at only the indicated subset of photovoltaic inputs.

[0023] The invention has the advantage that the photovoltaic inverter can continue to operate safely – albeit with reduced power – in the event of an arc flash. Prior art multi-string photovoltaic inverters generally shut down completely in the event of an arc flash, thus preventing a large and potentially damaging power surge. 2024P09334 DE

[0024] 4. Time until a repair occurs leads to increasing yield loss. In contrast, the photovoltaic inverter according to the invention makes it possible to selectively deactivate the photovoltaic input or – in the case of joint monitoring of several photovoltaic inputs for an arcing event – ​​those photovoltaic inputs at which the arcing event occurred. The photovoltaic modules or photovoltaic strings connected to the remaining photovoltaic inputs can continue to operate unaffected, which reduces the yield loss and greatly reduces the urgency of repair and fault rectification.

[0025] For example, the control unit can be configured to switch off the DC / DC converter group connected between the displayed subset of photovoltaic inputs and the DC link. Switching off the DC / DC converter group terminates the current flow through the photovoltaic inputs of the displayed subset of photovoltaic inputs, thus extinguishing the arc.

[0026] In embodiments of the invention where a DC / DC converter group comprises several DC / DC converters, each DC / DC converter being connected downstream of one of the photovoltaic inputs of the respective subset of photovoltaic inputs, the control unit can be configured to iteratively reactivate one or more selections of DC / DC converters from the DC / DC converter group after the DC / DC converter group has been switched off, up to a further signal from the arc detector or up to a maximum number of selections of DC / DC converters, thereby determining the photovoltaic input where an arc fault is present. This means that the control unit searches within the DC / DC converter group and the subset of photovoltaic inputs for the photovoltaic input where the arc fault is present.If an arcing event occurs again after restarting a selection of DC / DC converters within the DC / DC converter group, the photovoltaic input where the problem exists has been identified. The iterative search can be performed using various algorithms. In the simplest case, each DC / DC converter can be restarted once, while the remaining DC / DC converters remain switched off. It is also possible to perform a binary search to reduce the number of restarts in a large DC / DC converter group with many DC / DC converters. Here, half of the DC / DC converters in the DC / DC converter group are restarted, and depending on the result of the arc detection, either one half or the other half—namely, the one where the arcing is suspected—is considered in the next step and halved again. Many other iterative search strategies are also conceivable. 2024P09334 DE.

[0027] 5

[0028] When restarting a selection of DC / DC converters, the control unit can also specify an operating power (i.e., an electrical power to be supplied to the DC link by the selected DC / DC converters from their associated photovoltaic inputs) and gradually or continuously increase this specified operating power after restarting up to a maximum operating power. Restarting with the (reduced) operating power serves to increase operational reliability, ensuring that if another arcing event occurs, the arc will have lower power and thus generate less heat.

[0029] The control unit is preferably configured to switch the displayed subset of the photovoltaic inputs to high impedance. This can be achieved in particular by opening a semiconductor switch of the DC / DC converter(s).

[0030] The feed-in converter is particularly preferably designed to regulate the DC link voltage to a first operating voltage. The control unit can then also be configured, in response to a signal from the arc detector, to control the feed-in converter and regulate the DC link voltage to a second operating voltage that is higher than the first. Increasing the DC link voltage counteracts the current flow from the DC / DC converter into the DC link and thus the current flow through the arc, allowing the arc to be extinguished.If the photovoltaic inverter according to the invention is operated with such an increased intermediate circuit voltage until a repair or maintenance measure is carried out, the re-ignition of an arc can also be prevented, so that the operational safety is increased in the (partial) continued operation of the photovoltaic inverter advantageously realized according to the invention.

[0031] In particular, the second operating voltage can be higher than the open-circuit voltage of the photovoltaic modules or strings connected or connectable to the subset of photovoltaic inputs. This completely prevents current flow from the subset of photovoltaic inputs to the DC link. Otherwise, the voltage at the switched-off photovoltaic input would rise to the open-circuit voltage due to the lack of power draw. This could cause a renewed or continuous current flow through the photovoltaic input affected by the arcing event into the DC link, especially in a DC / DC converter designed as a boost converter. This current could then sustain the arc. A current from the DC link to the photovoltaic modules or strings, however, is prevented by a 2024P09334 DE

[0032] 6

[0033] A blocking element of the DC / DC converter, such as a blocking diode, prevents the part of the photovoltaic inverter affected by the arcing event from being effectively and safely switched off by increasing the DC link voltage.

[0034] The photovoltaic inverter can be equipped with a battery input for a storage battery and a bidirectional battery charger connected between the DC link and the battery input and linked to the control unit. The control unit is configured to activate the bidirectional battery charger upon receiving a signal from the arc detector, extract electrochemical energy from the storage battery, and feed it into the DC link. This allows the DC link voltage to be increased more quickly than, for example, simply by reducing the power drawn from the DC link by the feed-in inverter.

[0035] Preferably, the control unit is also configured to output an arc fault signal to a fault indicator. The fault indicator can be located on the photovoltaic inverter itself and / or remotely, for example, connected to the photovoltaic inverter via a data link.

[0036] A second aspect of the invention introduces a photovoltaic arrangement with a plurality of photovoltaic modules or a plurality of photovoltaic strings, wherein the photovoltaic modules or photovoltaic strings are connected to a photovoltaic converter according to the first aspect of the invention.

[0037] Brief description of the images

[0038] The invention is described in more detail below with reference to preferred embodiments of the invention. The figures shown are:

[0039] Fig. 1 shows a first embodiment of a photovoltaic converter according to the invention as part of a photovoltaic arrangement according to the invention;

[0040] Fig. 2 shows a second embodiment of a photovoltaic inverter according to the invention; and

[0041] Fig. 3 shows a third embodiment of a photovoltaic inverter according to the invention. 2024P09334 DE

[0042] 7

[0043] Detailed description of the illustrations

[0044] Fig. 1 shows a first embodiment of a photovoltaic inverter 1 according to the invention as part of a photovoltaic arrangement according to the invention. The photovoltaic inverter 1 is connected on its output side to a supply network 2 in order to feed electrical energy into it. The electrical energy is provided by photovoltaic modules 3 by conversion from sunlight. In this example, the photovoltaic modules 3 are connected together to form several photovoltaic strings 4, with a series connection being chosen to provide a higher input voltage for the photovoltaic inverter 1. Other configurations are, of course, also conceivable, for example, with parallel connections of photovoltaic modules 3 in a photovoltaic string 4.It is also possible to connect several such photovoltaic strings 4 (at one photovoltaic input) in parallel to increase the power available at one photovoltaic input without having to further increase the voltage - for example by connecting the same number of photovoltaic modules 3 in series.

[0045] The photovoltaic strings 4 are each connected to one of several photovoltaic inputs 8 of the photovoltaic inverter 1. Removable plug or screw connections can be used for this purpose. Such connections simplify the installation of a photovoltaic array, but their removable nature can increase the risk of arcing. However, arcs can also occur at permanently connected terminals. To increase the safety of the array, the photovoltaic inverter 1 is therefore connected to an arc detector 12, which detects arcs, for example, by the light they emit, a temperature increase caused by them and / or its rate of increase, or characteristic disturbances in voltage or current at or through the photovoltaic input.In particular, the arc flash detector can also take several of these phenomena into account in combination (for example, a characteristic light emission together with a matching characteristic disturbance of voltage and / or current) to minimize the risk of false detection. For this purpose, the arc flash detector has several inputs and sensors (or sensor channels, shown here as signal lines from the photovoltaic inputs 8 to the arc flash detector 12), each of which is connected to a photovoltaic input 8 (Figure 1) or a group 16 of photovoltaic inputs (Figures 2 and 3). In the example of Figure 1, a group of photovoltaic inputs therefore comprises exactly one photovoltaic input 8; that is, for each photovoltaic input 8 of the photovoltaic inverter 1, there is a separate sensor channel on the arc flash detector. To reduce the complexity of the arc flash detector 12, the number of sensor channels can be reduced (see 2024P09334 DE).

[0046] The number of photovoltaic inputs 8 can be reduced. In this case, one sensor channel of the arc detector 12 is used for each group 16 of photovoltaic inputs 8 with two or more photovoltaic inputs 8. However, in such a case, the arc detector 12 may not be able to directly determine the exact location of the occurrence of an arc event within a group 16 of photovoltaic inputs 8.

[0047] Each photovoltaic input 8 is connected to a DC / DC converter 11, wherein the DC / DC converters 11, like the photovoltaic inputs 8, are grouped into DC / DC converter groups 10. In Figure 1, a DC / DC converter group 10 accordingly comprises one DC / DC converter 11, while in the embodiments shown in Figures 2 and 3, a DC / DC converter group 10 comprises several DC / DC converters 11, namely exactly as many as there are photovoltaic inputs 8 in a group 16 of photovoltaic inputs 8.

[0048] The DC / DC converters 11 serve to decouple the voltage of the photovoltaic modules 3 or the photovoltaic strings 4 applied to a respective photovoltaic input 8 from the intermediate circuit voltage of a DC link 7. The DC link 7 serves as a buffer storage for the electrical energy that is converted into alternating current by a feed-in inverter 6 and fed into the supply network 2. The DC link 7 can, in particular, include one or more capacitors. The intermediate circuit voltage is then determined as a result of the amount of electrical energy currently stored in the DC link 7. The intermediate circuit voltage will typically be at least as high as the maximum value of the alternating voltage generated by the feed-in inverter 6. The feed-in inverter 6 can control the intermediate circuit voltage via the electrical power drawn during the conversion process.If the feed-in inverter 6 draws more electrical power from the DC link 7 than the DC / DC converters 11 feed into the DC link 7 from the photovoltaic modules 3, the DC link voltage drops. Conversely, the DC link voltage rises if the feed-in inverter 6 draws less electrical power than the DC / DC converters 11 are currently providing.

[0049] Decoupling the voltage of the photovoltaic modules 3 from the DC link voltage offers the advantage that electrical power can be extracted from each photovoltaic string 4 at the instantaneous point of maximum power (Maximum Power Point, MPP). This MPP varies with different operating parameters and can be identified and tracked during operation using various methods. These methods are part of the technical background 2024P09334 DE.

[0050] 9 of the present invention and are at least partially known to the person skilled in the art from his basic knowledge, which is why they will not be discussed further here.

[0051] The photovoltaic inverter 1 of Figure 1 is equipped with a battery input 9 and a storage battery 5 connected thereto. A bidirectional battery charger 14 (also called a battery management system) is connected between the battery input 9 and the DC link 7, which serves to charge or discharge the storage battery 5. However, the invention can also be implemented without a storage battery 5 and consequently the photovoltaic inverter 1 without a battery input 9 and without a battery charger 14.

[0052] The photovoltaic inverter 1 according to the invention is equipped with a control unit 13, which is connected to the arc flash detector 12, the DC / DC converters 11, and the feed-in inverter 6. The control unit 13 need not be a single central unit, but can also be designed as a distributed system with several sub-control units. In the example shown in Figure 1, which is equipped with the bidirectional battery charger 14, the control unit 13 is also connected to the charger. In all embodiments of the invention, a fault indicator 15 can also be provided, which serves to indicate the occurrence of an arc flash event. The fault indicator 15 can be located on the photovoltaic inverter 1 as part of it, or alternatively or additionally at a remote location such as a monitoring center.

[0053] According to the invention, the control unit 13 is designed to interrupt the supply of PV electrical energy to the DC link at only the subset of photovoltaic inputs indicated by the signal from the arc detector 12, upon receiving a signal indicating the occurrence of an arc flash. The interruption of the current flow then extinguishes the arc flash. The energy supplied by the other photovoltaic strings 4 continues to be used, i.e., fed into the DC link 7 via the DC / DC converters 11 connected to them, and from there converted by the feed-in inverter 6 and fed into the supply network 2. This minimizes the economic damage resulting from the occurrence of an arc flash.

[0054] There are several ways to interrupt the supply of PV electrical energy to the DC link at the photovoltaic inputs 8 indicated by the arc detector 12. For example, the DC / DC converters 11 of the associated DC / DC converter group 10 can be switched to high impedance. This can be done by opening a switch. This switch could, for example, be a semiconductor switch of the DC / DC converter 11, which 2024P09334 DE

[0055] 10 is provided for DC / DC switching. In the boost converters typically used as DC / DC converters in the photovoltaic inverter according to the invention, a current flow in a coil is generated during DC / DC switching by closing a semiconductor switch. The semiconductor switch is then opened again. The magnetic field of the coil briefly maintains the current flow through the coil, causing the voltage across the coil to rise, which in turn results in a current flow to a node at a higher voltage than at the other terminal of the coil. To prevent a reverse current from the DC link 7 through the coil, a further semiconductor switch can be provided, which opens when the first semiconductor switch is opened. Such a DC / DC converter can, for example, be switched to high impedance by opening both semiconductor switches.

[0056] It is also possible to reduce or stop the current flow through the arc and thus extinguish the arc by increasing the DC link voltage, which counteracts the current flow through the DC / DC converter. For this purpose, the control unit 13 can control the power converter 6 to reduce the electrical power drawn from the DC link 7 (in particular below the power fed into the DC link 7). This measure can be taken in addition to switching the DC / DC converter to the high-impedance state. In embodiments of the photovoltaic converter 1 according to the invention with a bidirectional battery charger 14 and an associated storage battery 5, the control unit 13 can also be configured to control the bidirectional battery charger 14, draw energy from the storage battery 5, and feed it into the DC link 7.This measure can alternatively or additionally be used to increase the intermediate circuit voltage in order to reduce the current flow through the arc.

[0057] It may be possible to reduce the intermediate circuit voltage again after the arc has extinguished, which is particularly useful if the photovoltaic input 8 or the photovoltaic inputs 8, at which the arc occurred, have been switched to high resistance in the meantime.

[0058] Fig. 2 shows a second embodiment of the photovoltaic inverter 1 according to the invention. The second embodiment largely corresponds to that of Fig. 1, except that a bidirectional battery charger and a battery input have been omitted. These could, however, also be provided in the illustrated embodiment. In order to save on the complexity of the arc detector 12, several photovoltaic inputs 8 in the second embodiment were grouped together into a group 16, which are connected collectively, i.e., by each 2024P09334 DE

[0059] 11 a sensor channel of the arc detector 12 is monitored. However, this means that if an arc flash occurs at one of the photovoltaic inputs 8 of the affected group 16, the arc detector 12 will output a corresponding signal to the control unit 13. The signal cannot provide information about which photovoltaic input 8 the arc flash was detected at, but only indicates the group 16. Therefore, the control unit 13 accordingly terminates the supply of PV energy to the DC link 7 for the entire group 10 of photovoltaic inputs 8. In the embodiment shown in Figure 2, the control unit 13 is connected to all DC / DC converters 11 of the associated DC / DC converter group 10, so that it can only deactivate all these DC / DC converters 11 together (in particular, it can also switch them to high impedance).

[0060] Fig. 3 shows a third embodiment of the photovoltaic inverter 1 according to the invention, which is again very similar to the previous embodiment. Therefore, what was said there also applies to the third embodiment, unless otherwise stated below. Here, several photovoltaic inputs 8 and corresponding DC / DC converters 11 are again grouped into groups 16, 10. However, the control unit 13 is connected to the DC / DC converters 11 in such a way that it can switch individual DC / DC converters 11 within a DC / DC converter group 10 to high impedance and / or deactivate them. As described above, the control unit 13 can be configured to identify, by applying an iterative process, the photovoltaic input 8 at which the arcing event occurred (or occurs again after reconnection) and to deactivate only this photovoltaic input 8 for further operation.This means that the third embodiment of the invention makes it possible to obtain the advantage of the reduced effort for the arc detector 12 without the disadvantage of the second embodiment, in which entire groups 16, 10 of photovoltaic inputs 8 or DC / DC converters 11 have to be permanently deactivated until a maintenance measure.

[0061] The invention offers the advantage of providing protection against damage caused by an arc flash without requiring a complete shutdown of the photovoltaic inverter when such an event occurs. This reduces the economic damage in the form of lost earnings resulting from the arc flash.

[0062] The invention has been explained in more detail with reference to exemplary embodiments. These exemplary embodiments serve to improve understanding and are not intended to limit the invention, which is defined exclusively by the following claims. 2024P09334 DE

[0063] Reference symbol list

[0064] 1 photovoltaic inverter

[0065] 2 Supply network 3 Photovoltaic module

[0066] 4 photovoltaic string

[0067] 5 Storage battery

[0068] 6 feed-in inverters

[0069] 7 DC link 8 Photovoltaic input

[0070] 9 Battery input

[0071] 10 DC / DC converter group

[0072] 11 DC / DC converters

[0073] 12 Arc detector 13 Control unit

[0074] 14 bidirectional battery charger

[0075] 15 Error message

[0076] Group of 16 photovoltaic inputs

Claims

2024P09334 DE 13 Patent claims 1. A photovoltaic inverter (1) comprising a feed-in inverter (6) configured to extract electrical energy stored in a DC link (7), to convert the extracted stored electrical energy into an AC link, and to feed the converted electrical energy into a supply network (2), a plurality of photovoltaic inputs (8) for at least one photovoltaic module (3) or at least one photovoltaic string (4), an arc detector (12) configured to detect the occurrence of an arc event at one of the photovoltaic inputs (8), and a plurality of DC / DC converter groups (10) connected between a respective subset of the plurality of photovoltaic inputs (8) and the DC link (7) and configured to measure the voltage at the respective subset (8,16) to extract the respective PV electrical energy available from the photovoltaic inputs (8) and feed it into the DC link (7), and a control unit (13) connected to at least the arc detector (12) and the feed-in converter (6), characterized in that the arc detector (12) is also configured to indicate to the control unit (13) with a signal the subset (8, 16) of the photovoltaic inputs (8) at which the arcing event occurred, and that the control unit (13) is configured to interrupt, upon receiving the signal from the arc detector (12), the supply of PV electrical energy to the DC link (7) at only the indicated subset (8, 16) of the photovoltaic inputs (8).

2. The photovoltaic converter (1) of the preceding claim, wherein the control unit (13) is configured to switch off the DC / DC converter group (10) connected between the displayed subset (8, 16) of the photovoltaic inputs (8) and the DC intermediate circuit (7).

3. The photovoltaic converter (1) of the preceding claim, wherein a DC / DC converter group (10) comprises several DC / DC converters (11), each of the DC / DC converters (11) being connected downstream of one of the photovoltaic inputs (8) of the respective subset (16) of the photovoltaic inputs (8), and wherein the control unit (13) is configured to iteratively switch on one or more selections of DC / DC converters (11) of the DC / DC converter group (10) after the DC / DC converter group (10) has been switched off, up to a further signal from the arc detector (12) or up to a maximum number of selections of DC / DC converters (11), and thereby to determine the photovoltaic input (8) at which an arc fault is present. 2024P09334 DE 14 4. The photovoltaic converter (1) of the preceding claim, wherein the control unit (13) is further configured to specify an operating power to the selection of DC / DC converters (11) and to increase the specified operating power step by step or continuously up to a maximum operating power after reconnection.

5. The photovoltaic converter (1) of one of the preceding claims, wherein the control unit (13) is configured to switch the displayed subset (8, 16) of the photovoltaic inputs (8) to high impedance.

6. The photovoltaic converter (1) of one of the preceding claims, wherein the feed-in converter (6) is further configured to regulate an intermediate circuit voltage of the DC intermediate circuit (7) to a first operating voltage, wherein the control unit (13) is further configured to control the feed-in converter (6) in response to the signal from the arc detector (12) to regulate the intermediate circuit voltage to a second operating voltage which is higher than the first operating voltage.

7. The photovoltaic converter (1) of the preceding claim, wherein the second operating voltage is higher than an open-circuit voltage of the photovoltaic modules (3) or photovoltaic strings (4) connected or connectable to the subset (16) of the photovoltaic inputs (8).

8. The photovoltaic inverter (1) of one of the preceding claims, comprising a battery input (9) for a storage battery (5) and a bidirectional battery charger (14) connected between the DC link (7) and the battery input (9) and connected to the control unit (13), wherein the control unit (13) is configured to control the bidirectional battery charger (14) in response to the signal from the arc detector (12), to extract electrochemical energy from the storage battery (5) and to feed it into the DC link (7).

9. The photovoltaic converter (1) of one of the preceding claims, wherein the control unit (13) is further configured to output an arc fault signal to a fault indicator (15).

10. A photovoltaic arrangement (1 , 3, 4) comprising a plurality of photovoltaic modules (3) or a plurality of photovoltaic strings (4), wherein the photovoltaic modules (3) or photovoltaic strings (4) are connected to a photovoltaic converter (1) according to any of the preceding claims.

Images