Photovoltaic system

Abstract

The invention relates to a photovoltaic system (114). The photovoltaic system (114) comprises at least one photovoltaic module (116) designed to generate electrical energy, in the form of direct current, from solar energy; at least one inverter (118) designed to convert the direct current generated by the photovoltaic module (116) into alternating current and output the alternating current; at least one transformer (120) designed to convert the alternating current output by the inverter into an output alternating current with a specified voltage; at least one energy store (122) designed to temporarily store electrical energy; at least one network interface (128) designed to connect the photovoltaic system (114) to a public electricity supply network (130), the photovoltaic system (114) being designed to output and / or receive electrical energy via the network interface (128); and at least one controller (124) designed to cover the electrical demand of the photovoltaic system (114) at least partly using the electrical energy from the energy store (122) in an idle mode of the photovoltaic system (114) and, in a generation mode of the photovoltaic system (114), limit the output, via the network interface (128), of the electrical energy generated in the photovoltaic module (116) to a specified maximum value (P2) and temporarily store the electrical energy that is additionally generated in the photovoltaic module (116) in the energy store (122). The invention also relates to a method for operating a photovoltaic system (114).

Description

[0001] Photovoltaic system

[0002] Technical field

[0003] The invention relates to a photovoltaic system. Furthermore, the invention relates to a method for operating a photovoltaic system. Systems and methods of the aforementioned type can generally be used in the field of energy generation, particularly in the field of photovoltaics. Thus, the invention can be used, in particular, for generating electrical energy from light energy, for example, from solar energy. However, other areas of application are also conceivable in principle.

[0004] Technical background

[0005] Photovoltaic systems, particularly for generating electricity from solar energy, are well-known technology. They are typically installed on roofs or as ground-mounted systems and are oriented towards the sun. Photovoltaic systems usually consist of photovoltaic panels, which are either fixed in a position oriented towards the sun or are mounted in a movable position to track the sun's path.

[0006] EP 4018544 B1 discloses a photovoltaic system comprising an inverter designed to convert direct current power supplied to the inverter by photovoltaic modules of a photovoltaic generator via power cables into alternating current for an AC power grid, wherein the inverter has a base station connected by means of the power cables to the module-level devices for monitoring and / or controlling the associated photovoltaic modules of the photovoltaic generator, wherein, if the inverter does not receive sufficient energy from the photovoltaic generator and the AC power grid, a control system of the photovoltaic system is designed to activate a deadlock prevention mode of a power supply unit connected to the inverter, in which the inverter receives energy from the power supply unit, so that the base station of the inverter is able toto continue sending operating permit signals via the power cables to the devices at the module level of the photovoltaic generator.

[0007] Depending on the territory in which a photovoltaic system is installed, certain regulations must be observed, forming the regulatory basis for its operation. Compliance with these regulations typically requires a considerable amount of energy and thus generates high costs. Despite the advantages of well-known photovoltaic systems, numerous technical challenges remain. In particular, there is a continuing need to increase the economic viability of photovoltaic systems while simultaneously meeting increasingly stringent safety requirements.

[0008] Object of the invention

[0009] It would therefore be desirable to provide photovoltaic systems and methods for operating photovoltaic systems that largely avoid the disadvantages of known systems and methods of the aforementioned type. In particular, photovoltaic systems and methods for operating photovoltaic systems should be provided that, on the one hand, meet regulatory requirements and safety standards and, on the other hand, ensure high cost-efficiency, especially during repair and commissioning as well as in the subsequent operation of the photovoltaic system.

[0010] General description of the invention

[0011] This problem is addressed by a photovoltaic system and by a method for operating a photovoltaic system with the features of the independent patent claims. Advantageous further developments, which can be implemented individually or in any combination, are presented in the dependent claims.

[0012] In the following, the terms "have," "exhibit," "comprise," or "include," or any grammatical variations thereof, are used in a non-exclusive manner. Accordingly, these terms can refer both to situations in which, apart from the features introduced by these terms, no other features are present, and to situations in which one or more additional features are present. For example, the expression "A has B," "A exhibits B," "A comprises B," or "A includes B" can refer both to the situation in which, apart from B, no other element is present in A (i.e., a situation in which A consists solely of B) and to the situation in which, in addition to B, one or more other elements are present in A, such as element C, elements C and D, or even further elements.

[0013] It is further noted that the terms "at least one" and "one or more," as well as grammatical variations of these terms, when used in connection with one or more elements or features and intended to express that the element or feature may be provided once or multiple times, are generally used only once, for example, when the feature or element is first introduced. Upon subsequent mention of the feature or element, the corresponding term "at least one" or "one or more" is generally no longer used, without restricting the possibility that the feature or element may be provided once or multiple times. Furthermore, the terms "preferably," "in particular," "for example," or similar terms are used below in connection with optional features without limiting alternative embodiments.Features introduced by these terms are optional features, and it is not intended that these features limit the scope of protection of the claims, and in particular the independent claims. As the person skilled in the art will recognize, the invention can also be implemented using other embodiments. Similarly, features introduced by "in an embodiment of the invention" or by "in an exemplary embodiment of the invention" are understood as optional features, without this limiting alternative embodiments or the scope of protection of the independent claims. Furthermore, these introductory phrases are intended to leave all possibilities of combining the introduced features with other features, whether optional or non-optional, unaffected.

[0014] In a first aspect of the present invention, a photovoltaic system is proposed. The term "photovoltaic system," as used here, is a broad term and should be understood to have its ordinary and common meaning as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer, in particular, to any number of interacting or interdependent components that form a whole and are configured to convert light energy, for example, solar energy, into electrical energy, for example, to generate it, and to feed it into a public electricity grid. In particular, the components of the photovoltaic system can interact with one another to perform at least one common function, for example, generating electrical energy from light energy.In particular, the photovoltaic system can be designed as a ground-mounted system. For example, the photovoltaic system described in the present invention can be designed as a large-scale system, for example, for industrial power generation. In particular, the photovoltaic system can be configured for installation on open spaces and large rooftops, for example, as a ground-mounted system and / or a rooftop system, for example, on industrial buildings. Thus, the photovoltaic system described in the present invention can have a nominal power output of at least 0.135 megawatts (MW) according to standard test conditions. In particular, the photovoltaic system described in the present invention can comprise at least one system of type B, type C, and / or type D according to the Network Code "Requirements for Generators" (NC-RfG).The photovoltaic system can, for example, be a system of at least one of type B, type C, and type D, in accordance with Regulation (EU) 2016 / 631 "Requirements for Generators" and / or in accordance with at least one of the Technical Connection Rules (TAR). For example, the nominal power output of the photovoltaic system under standard test conditions can range from 0.135 MW to 700 MW. Specifically, the nominal power output of the photovoltaic system under standard test conditions can range from 1 MW to 200 MW. For example, the nominal power output of the photovoltaic system under standard test conditions can range from 5 MW to 70 MW. The photovoltaic system comprises at least one photovoltaic module configured to generate electrical energy in the form of direct current from solar energy, for example, from electromagnetic radiation emitted by the sun.The term "photovoltaic module," as used here, is a broad term to which its ordinary and common meaning, as understood by those skilled in the art, shall be attributed. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to a device of any shape, comprising a multitude of solar cells that generate electric current in response to incident electromagnetic radiation, such as sunlight.

[0015] Furthermore, the photovoltaic system includes at least one inverter configured to convert the direct current (DC) generated by the photovoltaic module into alternating current (AC) and to output the AC. The term "inverter," as used here, is a broad term and should be understood in its usual and common sense, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to a voltage converter configured to generate an alternating voltage from a DC input voltage. The inverter can, in particular, convert the DC input current, also referred to as input DC current, into an AC output current.

[0016] Furthermore, the photovoltaic system includes at least one transformer designed to convert the alternating current output by the inverter into an output alternating current of a predetermined voltage, in particular a voltage specified for a public electricity supply network. The term "transformer," as used here, is a broad term and should be understood in its usual and common sense, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to an electrical machine designed to generate an alternating voltage, also referred to as an output alternating voltage, from a supply alternating voltage, for example, also referred to as an input alternating voltage, with a different frequency.For example, a transformer can be designed to change the voltage of an input AC voltage and thus generate an output AC voltage that differs in voltage from the supplying AC voltage. For instance, the transformer can change the output AC voltage relative to the input AC voltage, particularly to adapt the output AC voltage to a predefined voltage, such as the voltage of the public electricity supply network.

[0017] Furthermore, the photovoltaic system includes at least one energy storage device designed for the intermediate storage of electrical energy. The term "energy storage device," as used here, is a broad term and should be understood in its usual and common sense, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to any device designed to receive, store, and release electrical energy. Examples of such energy storage devices are explained in more detail below. The energy storage device can, in particular, act as an electrical buffer and / or be designed as such, i.e., as a device suitable or designed for the intermediate storage of electrical energy.Thus, at least one energy storage unit of the photovoltaic system can be set up as a whole or in parts for the intermediate storage of electrical energy.

[0018] Furthermore, the photovoltaic system includes at least one grid interface configured for connecting the photovoltaic system to a public electricity supply network. Specifically, the photovoltaic system can include exactly one grid interface configured for connecting the photovoltaic system to a public electricity supply network. The photovoltaic system is configured to supply and / or receive electrical energy via the grid interface, in particular to and / or from the public electricity supply network. The public electricity supply network can, for example, be a network selected from the group consisting of: a low-voltage network, a medium-voltage network, a high-voltage network, and an extra-high-voltage network. The low-voltage network can, for example, have an alternating voltage in the range of 50 V to 1,000 V. The medium-voltage network can, for example, have an alternating voltage in the range of 1.The high-voltage grid, for example, can have an alternating voltage in the range of 35,001 V to 110,000 V. The extra-high-voltage grid, for example, can have an alternating voltage in the range of 110,001 V or greater. In particular, the photovoltaic system can have exactly one grid interface.

[0019] Furthermore, the photovoltaic system includes at least one control unit. This control unit is designed to cover at least part of the photovoltaic system's own electrical demand during idle mode using electrical energy from the energy storage system. Additionally, during generation mode, the control unit is designed to limit the output of electrical energy generated in the photovoltaic module, and in particular in the photovoltaic system itself, to a predetermined maximum value via the grid interface, and to temporarily store any electrical energy generated beyond this limit in the at least one energy storage unit.

[0020] The term "control system," as used here, is a broad term and should be understood in its usual and common sense, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to any device configured to control and / or monitor at least one function of the photovoltaic system. The control system can, in particular, include at least one data processing device, for example, at least one processor. For example, the control system can be a centralized or decentralized system control system, in particular a machine control system, which can be configured to direct and / or monitor the photovoltaic system, especially the current flow within the photovoltaic system. For example, the control system can be implemented wholly or partially by software.In addition to at least one data processing device, the control system can also include at least one physical component, in particular at least one controller. For example, the controller can comprise at least one device and / or system to implement at least one control function. Thus, the control system can include, in particular, a controller configured to influence the function of the photovoltaic system, also referred to as the "control loop" of the control system, in such a way that the power generation of the photovoltaic system and the current flow within the photovoltaic system are directed and / or monitored in a predetermined and / or defined manner. For example, the controller can also be referred to as a "park controller." Accordingly, the control system can be partially implemented using hardware.Furthermore, the control system can be set up to control the photovoltaic system in at least two different operating modes, also referred to as operating states, which will be explained in more detail below.

[0021] For example, the control system can also be configured to implement power curtailment, such as in the event of grid congestion and / or negative electricity prices, particularly when the electrical energy generated by the photovoltaic system cannot and / or should not be fed into a public electricity grid. The control system can be configured, for instance, to implement power curtailment if the electrical energy generated by the photovoltaic system cannot or should not be fed into the upstream grid via the grid connection point. This power curtailment can, for example, involve converting the electrical energy generated by the at least one photovoltaic module into power loss, specifically as waste heat, for example, in inverters and / or transformers.Power reduction can be implemented, for example, by means of one or more controllers of the photovoltaic system's control system, such as the park controller.

[0022] The term "idle mode," as used here, is a broad term and should be understood in its usual and common sense, as understood by those skilled in the art. The term is not limited to a specific or adapted meaning. Without restriction, the term can refer in particular to an operating mode and / or operating state of the photovoltaic system in which little or no energy is generated. Thus, idle mode can refer specifically to an operating state of the photovoltaic system that occurs at night and / or in darkness, for example, when there is a solid cloud cover. The "idle mode" can also be referred to synonymously as "dark mode" and / or "idle operation."As detailed below, a predetermined threshold, for example a maximum value of the energy generated by the photovoltaic system, can serve as a limit for determining whether the photovoltaic system is in idle mode or not.

[0023] The term "personal use" 1The term "self-consumption," as used here, is a broad term to which its usual and common meaning, as understood by those skilled in the art, should be attributed. The term is not limited to a specific or adapted meaning. Without limitation, the term can refer in particular to a quantity of electrical energy necessary for the operation of the components of the photovoltaic system. Thus, self-consumption can, for example, include the electrical energy, and in particular consist of the electrical energy generated by all components of the photovoltaic system as a whole. Specifically, the electrical self-consumption of the photovoltaic system can occur in both idle and generation modes.

[0024] The term "generation mode," as used here, is a broad term to which its usual and common meaning, as understood by those skilled in the art, should be attributed. The term is not limited to a specific or adapted meaning. Without limitation, the term can refer in particular to an operating mode and / or operating state of the photovoltaic system in which energy generation takes place, especially in the at least one photovoltaic module. Thus, the generation mode can refer in particular to an operating state of the photovoltaic system that occurs during the day and under so-called clear skies, i.e., for example, with an open cloud cover or a cloudless sky.As explained in more detail below, a predefined threshold, for example a limit value for the energy generated by the photovoltaic module, can serve as a boundary for determining whether the photovoltaic system is in generation mode or not. In particular, the threshold value can serve as a distinguishing criterion between whether the photovoltaic system is in generation mode or in idle mode.

[0025] In particular, the photovoltaic system can have at least one, for example at least two, energy storage devices. For example, the photovoltaic system can also have multiple energy storage devices. Specifically, the at least one energy storage device can be designed, in whole or in part, for the intermediate storage of electrical energy. For example, the photovoltaic system's own electrical demand during idle mode can be covered by one of the at least two energy storage devices. Furthermore, a portion of the electrical energy generated in the photovoltaic module that exceeds the maximum value, especially the electrical energy generated during generation mode, can be temporarily stored in a second of the at least two energy storage devices.

[0026] For example, the control system can be configured to distribute the electrical energy generated in the photovoltaic module to at least two energy storage devices in such a way that the first of the at least two energy storage devices stores energy for self-consumption, and at least the second of the at least two energy storage devices stores excess energy, which is then fed into the grid via the grid interface during a subsequent idle mode. Alternatively, the control system can be configured to distribute the electrical energy generated in the photovoltaic module to at least two energy storage devices according to a predefined scheme, for example, evenly, and to store energy in such a way that both the energy for self-consumption and the excess energy can be drawn from any one of the at least two energy storage devices.For example, at least one energy storage unit of the photovoltaic system can be installed to exclusively cover the system's own energy needs. Thus, the photovoltaic system, and in particular its control system, can be configured, for example, to use the energy temporarily stored in the first energy storage unit solely to cover the photovoltaic system's own energy needs.

[0027] In particular, the electrical self-consumption of the photovoltaic system can have both a load-independent component and a load-dependent component.

[0028] The load-independent portion of the photovoltaic system's own electrical consumption can include, for example, electrical energy required by active components, such as inverters and optionally one or more control units and / or monitoring systems, for the operation of these active components. Load-independent energy losses, so-called iron losses, can also occur in the at least one transformer, primarily in the transformer's magnetic core.

[0029] The load-dependent component can include, in particular, the photovoltaic system's own electrical consumption, which comprises energy losses in the system's components that depend on the current flow. Specifically, the load-dependent component of the photovoltaic system's own electrical consumption can include, for example, energy losses incurred at the at least one transformer and / or at least one power cable, which depend on at least one property of the electrical energy flowing through them. The load-dependent component of the system's own electrical consumption can, for example, include all load-dependent transmission losses in the power cables, especially in AC power cables and / or DC power cables.Alternatively or additionally, the load-dependent portion of the electrical self-consumption can include in particular all load-dependent losses, so-called copper losses, of the at least one transformer, in particular all transformers, of the photovoltaic system which arise, for example, from the electrical resistance of the windings of the transformer.

[0030] For example, the electrical self-consumption of the photovoltaic system can include at least one component, i.e., at least one share selected from the group consisting of: an electrical energy demand of at least one active unit of the photovoltaic system, for example the control unit and / or a regulator, a load-independent or load-dependent electrical loss of equipment of the photovoltaic system, for example of the at least one transformer and / or at least one power cable, an active power of the at least one inverter, especially in the case of a reactive power requirement by an operator of a public electricity supply network to which the photovoltaic system can be connected.

[0031] In particular, the self-consumption of electricity by the photovoltaic system in generation mode can differ from the self-consumption of electricity by the photovoltaic system in idle mode. The at least one energy storage device of the photovoltaic system can include at least one electrical energy storage device. This electrical energy storage device can be selected, in particular, from the group consisting of: sodium-sulfur battery (NaS battery), lithium-ion battery (Li-ion battery), sodium-nickel-chloride battery (NaNiCI battery), nickel-zinc battery (NiZn battery), sodium-ion battery (Na-ion battery), redox flow batteries (vanadium redox battery, sodium bromide redox battery, zinc-bromine battery), lead-acid battery, ultracapacitor (supercap).In the context of the present invention, an ultracapacitor, also known as a "supercap," is generally understood to be a high-capacitance double-layer capacitor based on the dissociation of ions in a liquid electrolyte, forming a dielectric with few atomic layers and a large electrode surface area. Combinations of the aforementioned electrical energy storage devices and / or other types of energy storage devices are also fundamentally possible. For example, the electrical energy storage device can include at least one electrical energy converter that converts the electrical energy stored in the device before it is made available to at least one other component of the photovoltaic system, such as another inverter and / or another transformer.

[0032] For example, at least one energy storage system can comprise a sodium sulfate battery. The energy storage system can, for instance, include a transformer and / or inverter to convert the energy stored in the sodium sulfate battery. Similarly, the photovoltaic system, associated with the energy storage system, can include at least one additional transformer and / or inverter.

[0033] For example, the energy storage system comprising the NaS battery can advantageously have a high energy density and be designed to store or release energy over extended periods, such as several hours. In this way, the NaS battery can be particularly advantageous in a photovoltaic system whose average charging or discharging time is between 6 and 12 hours.

[0034] The control system can be configured, in particular, to cover the remaining electricity demand of the photovoltaic system by drawing on electricity from the grid if the energy from the energy storage system is insufficient to fully meet its own electrical needs. This allows the system to cover the remaining electricity demand, especially during idle mode, if the energy temporarily stored in the energy storage system (e.g., the first storage unit) is depleted.Alternatively or additionally, the control system can be configured to feed the electrical energy temporarily stored in the energy storage system during generation mode—in particular, the electrical energy generated in the photovoltaic module in excess of the specified maximum value and temporarily stored in the energy storage system (e.g., in a second energy storage unit)—into the public electricity grid via the grid interface during a subsequent idle mode. For example, a surplus of electrical energy generated during generation mode can be temporarily stored in the energy storage system and fed into the electricity grid with a time delay, for example, afterward, as soon as no or less energy is being generated in the at least one photovoltaic module.

[0035] The at least one control unit can, in particular, include at least one current meter. The current meter can, for example, be configured to determine, and in particular measure, the electrical energy generated in the photovoltaic module. For instance, the current meter can measure the direct current generated in the photovoltaic module. The current meter can also, for example, determine, and in particular measure, the electrical energy generated by the entire photovoltaic system, such as the energy generated by the at least one photovoltaic module minus the system's own energy consumption. For this purpose, the current meter can, for example, be located at and / or near the grid interface to determine, and in particular measure, the electrical energy supplied to the public electricity grid.The electrical energy measurement by the controller's current meter can take place, for example, at the grid interface, such as a grid connection point, i.e., at the metering point and / or billing point between a plant operator and the operator of the public electricity grid. In this way, the lossy conversion chain from DC generation in the at least one photovoltaic module to the grid interface, i.e., to a feed-in point, can already be covered by the current meter measurement. An alternative arrangement of the current meter, for example, directly on the at least one photovoltaic module, is also possible.

[0036] Furthermore, the at least one control system can include at least one comparison logic. The comparison logic can, for example, be configured to compare the electrical energy generated in the photovoltaic module with at least one predefined threshold. In particular, the comparison logic can be configured to compare the electrical energy determined, especially measured, by the current meter with the predefined threshold.

[0037] Furthermore, the at least one controller can include at least one operating mode determination unit. The operating mode determination unit can, for example, be configured to determine the operating mode and / or operating state of the photovoltaic system. For instance, if the electrical energy is greater than or equal to the predefined threshold, the operating mode of the photovoltaic system can be generation mode. Alternatively, if the electrical energy is less than or equal to the predefined threshold, the operating mode of the photovoltaic system can be idle mode.

[0038] In particular, the control system can be set up to cover the photovoltaic system's own electrical needs in generation mode from the direct current generated in the photovoltaic module.

[0039] The photovoltaic system can, for example, have a large number of inverters and photovoltaic modules. Thus, the photovoltaic system can include at least two, and especially more than two, inverters and / or photovoltaic modules.

[0040] In particular, the number of inverters and photovoltaic modules in the photovoltaic system can be the same. For example, the photovoltaic system can have exactly the same number of inverters as photovoltaic modules. For instance, each photovoltaic module can be assigned exactly one inverter.

[0041] The photovoltaic system can include at least one busbar. The term "busbar," as used here, is a broad term and should be understood in its usual and common sense, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to an electrical component designed to conduct electrical energy. For example, the busbar can include an electrical conductor, in particular one made of an electrically conductive material, such as copper. Specifically, the busbar can comprise an arrangement of several electrical conductors and be designed to serve as a central distribution point for electrical energy, for example, in the form of one or more switchgear assemblies.

[0042] For example, all components of the photovoltaic system can be connected to the busbar, either indirectly or directly, for instance, electrically connected to it. The busbar can be located, for example, between the at least one photovoltaic module and the at least one electrical energy storage device. If the photovoltaic system includes multiple energy storage devices, the busbar can be located between the at least one photovoltaic module and the multiple energy storage devices.

[0043] The term "electrically connected," as used here, is a broad term and should be interpreted according to its usual and common meaning, as understood by those skilled in the art. The term is not limited to any specific or adapted meaning. Without limitation, the term can refer in particular to the connection of at least two electrical components to enable current flow between them, for example, by using at least one power cable. The terms "connected," "connected," and / or "connect" can, for example, be used synonymously with the term "electrically connected." For instance, the grid interface can be connected directly or indirectly to the busbar. The photovoltaic system can, for example, include at least one additional transformer, i.e., it may have at least two, and in particular more than two, transformers.For example, the busbar can be indirectly connected to the grid interface via at least one other transformer of the photovoltaic system. In particular, the number of transformers between the busbar and the grid interface may depend on the type of public electricity supply network. For instance, when connected to the high-voltage and / or extra-high-voltage grid, at least one transformer may be required between the busbar and the grid interface, whereas when connected to the medium-voltage grid, it may be possible to omit a transformer between the busbar and the grid interface.

[0044] Alternatively or additionally, at least one photovoltaic module, or more than one photovoltaic module at a time, can be connected directly or indirectly to the busbar, for example via at least one inverter and at least one transformer. Furthermore, alternatively or additionally, at least one electrical energy storage device can also be connected directly or indirectly to the busbar, for example via at least one transformer.

[0045] In a further aspect of the present invention, a method for operating a photovoltaic system is proposed. The method comprises the steps described in more detail below. These steps can be carried out in the stated order. However, a different order is also fundamentally possible. Furthermore, two or more of the stated process steps can be carried out overlapping in time or simultaneously. Additionally, one or more of the stated process steps can be carried out once or repeatedly. The method may include further process steps beyond those mentioned, which are not specified.

[0046] The procedure for operating a photovoltaic system includes the following steps:

[0047] a) Provision of a photovoltaic system comprising at least one photovoltaic module configured for generating electrical energy in the form of direct current from solar energy, at least one inverter configured for converting the direct current generated by the photovoltaic module into alternating current and for outputting the alternating current, at least one transformer configured for converting the alternating current output by the inverter into an output alternating current of a specified voltage, in particular a voltage specified for a public electricity supply network, at least one energy storage system configured for intermediate storage of electrical energy, at least one grid interface configured for connecting the photovoltaic system to the public electricity supply network, at least one control system;

[0048] b) Determine, using the control system of the photovoltaic system, whether the photovoltaic system is in idle mode or in generation mode; c) If the photovoltaic system is in generation mode: Feed in, in particular optionally, using the control system, into the energy storage system of the photovoltaic system and / or via the grid interface into the public electricity supply network of electrical energy generated in the photovoltaic module, whereby the feed-in via the grid interface is limited to a predetermined maximum value by means of the control system, whereby any electrical energy generated in the photovoltaic module beyond this value is temporarily stored in the energy storage system;

[0049] d) If the photovoltaic system is in idle mode: Cover, by means of the control system, the electrical self-consumption at least partially by means of electrical energy from the at least one energy storage system.

[0050] Step c) of the procedure may, in particular, include a decision, for example in the control system, as to whether the generated energy is fed into the energy storage system or whether it is fed into the public electricity grid via the grid interface. This decision may depend, in particular, on whether the generated energy exceeds a predetermined maximum value. The maximum value may, in particular, be a maximum feed-in power agreed upon with the grid operator at the grid connection point. Specifically, as long as the generated energy is less than or equal to the predetermined maximum value, the control system may be configured to ensure that the generated energy is fed into the electricity grid.If the generated energy exceeds the predefined maximum value, the control system can be configured to feed the excess energy (i.e., the surplus) into the photovoltaic system's energy storage unit. Specifically, the control system can be configured to feed energy into the storage unit until it is fully charged, meaning its capacity is exhausted and it can no longer absorb and store any more energy.

[0051] For example, if the battery storage system is fully charged and the energy generated by the photovoltaic system, particularly by the at least one photovoltaic module, exceeds the maximum value (i.e., the system's output is greater than the maximum feed-in power agreed upon with the grid operator at the grid connection point), the control system can be configured to implement power curtailment, also known as feed-in management. The power curtailment implemented by the control system in this case might involve, for example, reducing the voltage output of the at least one photovoltaic module to a very low level or even eliminating it entirely.Alternatively or additionally, the power curtailment can include converting the electrical energy generated by the at least one photovoltaic module above its maximum value into power loss, in particular as waste heat, for example in inverters and / or transformers. The power curtailment can be implemented by controlling the photovoltaic system, for example via one or more controllers, such as a park controller. For example, the photovoltaic system provided in step a) can be the photovoltaic system according to the invention in one or more of the embodiments described herein. Therefore, with regard to definitions of terms and embodiments of the photovoltaic system, reference can be made to the explanations of the photovoltaic system according to one or more of the embodiments described herein.

[0052] Step b) of the procedure may, for example, include the following sub-steps:

[0053] b1) Determining, in particular measuring, by means of at least one current measuring device of the control system, the electrical energy generated in the photovoltaic module, in particular the generated direct current;

[0054] b2) Comparing, by means of at least one comparison logic of the control, the electrical energy generated in the photovoltaic module with at least one predetermined threshold;

[0055] b3) Determine, by means of at least one operating mode determination unit of the control system, the operating mode of the photovoltaic system, wherein in the case that the electrical energy > the specified threshold, the operating mode of the photovoltaic system is the generation mode, and in the case that the electrical energy < the specified threshold, the operating mode of the photovoltaic system is the idle mode.

[0056] Step c) of the procedure may, for example, further include: covering the photovoltaic system's own electrical needs entirely from the direct current generated in the photovoltaic module.

[0057] Step d) of the procedure may, for example, include the following sub-steps:

[0058] d1) Determine whether the energy from the energy storage system is sufficient to fully cover the photovoltaic system's own electrical needs;

[0059] d2) if the energy from the at least one energy storage system is sufficient to fully cover the electrical self-consumption of the photovoltaic system: Covering the electrical self-consumption completely by electrical energy from the energy storage system;

[0060] d3) if the energy from the energy storage is insufficient to fully cover the photovoltaic system's own electrical demand: covering part of the photovoltaic system's own electrical demand with electrical energy from the energy storage and covering the remainder of the photovoltaic system's own electrical demand with electrical energy drawn from the grid interface

[0061] The proposed photovoltaic system and the proposed operating procedure offer numerous advantages over known systems and procedures of this type. In particular, the economic viability of the photovoltaic system, for example, its operation and / or commissioning, especially its cost-effective connection to the public energy grid, can be increased compared to known photovoltaic systems, while simultaneously fulfilling all regulatory requirements.For example, the proposed photovoltaic systems and methods for operating photovoltaic systems can be designed to comply with the Technical Connection Rules (TAR), such as at least one of the TAR Low Voltage (VDE-AR-N 4105), TAR Medium Voltage (VDE-AR-N 4110), TAR High Voltage (VDE-AR-N 4120), and TAR Extra-High Voltage (VDE-AR-N 4130), thereby enabling greater cost efficiency compared to known systems and methods of the aforementioned type. In particular, the proposed photovoltaic systems and methods for operating photovoltaic systems can include at least one system of type B, type C, and type D according to the Network Code "Requirements for Generators" (NC-RfG), ​​in particular according to Regulation (EU) 2016 / 631 "Requirements for Generators" and / or according to one of the aforementioned TAR.For example, the energy stored in the at least one energy storage unit allows the proposed photovoltaic system to operate without drawing energy from the public electricity grid, even at night.

[0062] For example, by combining several different battery technologies in the photovoltaic system, such as combining different storage durations of different electrical energy storage devices, and / or combining different response times of the different electrical energy storage devices, it may be possible to optimize the costs of the system.

[0063] In particular, the proposed systems and methods can, for example, make it possible to provide a specified amount of reactive power on demand at any time, especially at night, to support voltage maintenance in the public grid, without having to draw energy from the public electricity supply network. This allows the proposed systems and methods to offer greater cost efficiency and therefore increased economic viability compared to existing systems and methods.

[0064] For example, compared to conventional systems and methods, the proposed systems and procedures can enable more cost-efficient operation of the photovoltaic system, a more cost-effective design of the photovoltaic system, and a more cost-effective design of the public electricity supply grid, also referred to as the grid. For instance, by limiting the electrical energy fed into the grid from the photovoltaic system, the maximum connection power at the grid interface can be set lower than with a design based on maximum power. This can lead to a reduction in the maximum feed-in power agreed upon with the grid operator at the grid interface, also known as the grid connection point, and / or a reduction in the grid connection power agreed upon in the grid connection contract.For example, the proposed systems and processes can better utilize the grid interface, which is dimensioned for the lower selected maximum connection power, and thus operate at full load for a greater proportion of the time and reduce partial load operation. Furthermore, the equipment of the proposed systems and processes, such as inverters and transformers, as well as power cables, transfer stations, feed-in substations, etc., can be dimensioned for the lower selected maximum connection power, meaning they are suitable and configured for operation and are therefore more cost-effective than equipment dimensioned for the actual maximum connection power. Finally, the costs incurred for grid connection can also be reduced by selecting a lower maximum connection power.Furthermore, a network operator who operates the public electricity supply network can, for example, obtain additional power capacity for further energy generation plants and / or network customers in the network area through the proposed facilities and procedures.

[0065] In summary, without limiting further possible embodiments, the following embodiments are proposed:

[0066] Design 1. Photovoltaic system comprising

[0067] at least one photovoltaic module installed for generating electrical energy in the form of direct current from solar energy;

[0068] at least one inverter is installed to convert the direct current generated by the photovoltaic module into alternating current and to output the alternating current;

[0069] at least one transformer is provided for converting the alternating current output by the inverter into an output alternating current of a predetermined voltage, in particular a voltage specified for a public electricity supply network;

[0070] at least one energy storage system is installed for the intermediate storage of electrical energy; at least one, in particular exactly one, grid interface is installed for connecting the photovoltaic system to a public electricity supply network, in particular to a low-voltage network, for example having an alternating voltage in the range of 50 V to 1,000 V, a medium-voltage network, for example having an alternating voltage in the range of 1,001 V to 35,000 V, a high-voltage network, for example having an alternating voltage in the range of 35,001 V to 110,000 V, and an extra-high-voltage network, for example having an alternating voltage in the range greater than or equal to 110,001 V, wherein the photovoltaic system is configured to supply and / or receive electrical energy via the grid interface;

[0071] at least one controller is installed

[0072] • to cover at least part of the photovoltaic system's own electrical demand in idle mode with electrical energy from the energy storage system, and • to limit the output of electrical energy generated in the photovoltaic module via the grid interface to a predetermined maximum value in generation mode and to temporarily store any electrical energy generated in the photovoltaic module beyond this value in the energy storage system. Design form 2.Photovoltaic system according to the preceding claim, wherein the photovoltaic system has at least two energy storage devices, wherein the electrical self-consumption of the photovoltaic system in idle mode of the photovoltaic system is covered from a first of the at least two energy storage devices, wherein a proportion of the electrical energy generated in the photovoltaic module exceeding the maximum value is temporarily stored in a second of the at least two energy storage devices.

[0073] Embodiment 3. Photovoltaic system according to one of the preceding claims, wherein the electrical self-consumption of the photovoltaic system has both a load-dependent component and a load-independent component.

[0074] Embodiment 4. Photovoltaic system according to one of the preceding claims, wherein the electrical self-consumption of the photovoltaic system comprises at least one component selected from the group consisting of: an electrical energy demand of at least one active unit of the photovoltaic system, for example the control unit and / or a regulator, a load-independent or load-dependent electrical loss of equipment of the photovoltaic system, for example the at least one transformer and / or at least one power cable, an active power of the at least one inverter, in particular in the case of a reactive power requirement by an operator of a public electricity supply network to which the photovoltaic system can be connected.

[0075] Embodiment 5. Photovoltaic system according to one of the preceding claims, wherein the at least one energy storage device, in particular the at least two energy storage devices, comprises at least one electrical energy storage device selected from the group consisting of: sodium-sulfur battery (NaS battery), lithium-ion battery (Li-ion battery), sodium-nickel-chloride battery (NaNiCI battery), nickel-zinc battery (NiZn battery), sodium-ion battery (Na-ion battery), redox flow batteries (vanadium redox battery, sodium bromide redox battery, zinc-bromine battery), lead-acid battery, ultracapacitor (supercap).

[0076] Embodiment 6. Photovoltaic system according to one of the preceding claims, wherein the control system is configured to cover a remaining portion of the photovoltaic system's electrical energy demand by means of electrical energy absorbed through the grid interface in the event that the energy from the energy storage system, in particular from the first and / or the second energy storage system, is insufficient to fully cover the photovoltaic system's electrical energy demand in idle mode.

[0077] Embodiment 7. Photovoltaic system according to one of the preceding claims, wherein the control system is configured to release the electrical energy temporarily stored in the energy storage system during the generation mode, in particular the electrical energy generated in the photovoltaic module in excess of the specified maximum value and temporarily stored in the energy storage system, to the public electricity grid via the grid interface in a subsequent idle mode. Embodiment 8. Photovoltaic system according to one of the preceding claims, comprising at least one control system.

[0078] • at least one current measuring device set up to determine, in particular measure, the electrical energy generated in the photovoltaic module, in particular the generated direct current,

[0079] • at least one comparison logic is set up to compare the electrical energy generated in the photovoltaic module with at least one predefined threshold,

[0080] • at least one operating mode determination unit is set up to determine an operating mode of the photovoltaic system, wherein in the case that the electrical energy > the specified threshold, the operating mode of the photovoltaic system is the generation mode, wherein in the case that the electrical energy < the specified threshold, the operating mode of the photovoltaic system is the idle mode, wherein the control is set up to cover the electrical self-consumption of the photovoltaic system from the direct current generated in the photovoltaic module in the generation mode.

[0081] Embodiment 9. Photovoltaic system according to one of the preceding claims, wherein the photovoltaic system comprises a plurality of inverters and photovoltaic modules, wherein a number of inverters and photovoltaic modules is the same.

[0082] Embodiment 10. Photovoltaic system according to one of the preceding claims, wherein the photovoltaic system comprises at least one busbar, wherein the busbar is arranged between the at least one photovoltaic module and the at least one electrical energy storage device.

[0083] Embodiment 11. Method for operating a photovoltaic system, comprising

[0084] a) Provision of a photovoltaic system comprising at least one photovoltaic module configured for generating electrical energy in the form of direct current from solar energy, at least one inverter configured for converting the direct current generated by the photovoltaic module into alternating current and for outputting the alternating current, at least one transformer configured for converting the alternating current output by the inverter into an output alternating current of a specified voltage, in particular a voltage specified for a public electricity supply network, at least one energy storage system configured for intermediate storage of electrical energy, at least one grid interface configured for connecting the photovoltaic system to the public electricity supply network, at least one control system;

[0085] b) Determine, using the control system of the photovoltaic system, whether the photovoltaic system is in an idle mode or in a generation mode;

[0086] c) If the photovoltaic system is in generation mode: feeding in, in particular optionally, via the control system, into the energy storage system of the photovoltaic system and / or via the grid interface into the public electricity supply network of electrical energy generated in the photovoltaic module, whereby the feed-in via the grid interface is limited to a predetermined maximum value by means of the control system, whereby any electrical energy generated in the photovoltaic module beyond this value is temporarily stored in the energy storage system;

[0087] d) If the photovoltaic system is in idle mode: Cover, by means of the control system, the electrical self-consumption at least partially by means of electrical energy from the at least one energy storage system.

[0088] Embodiment 12. Method according to the preceding claim, wherein the photovoltaic system is a photovoltaic system according to one of the preceding claims relating to a photovoltaic system.

[0089] Embodiment 13. Method according to one of the two preceding claims, wherein step b) comprises: b1) Determining, in particular measuring, by means of at least one current measuring device of the control, the electrical energy generated in the photovoltaic module, in particular the generated direct current;

[0090] b2) Comparing, by means of at least one comparison logic of the control, the electrical energy generated in the photovoltaic module with at least one predetermined threshold;

[0091] b3) Determine, by means of at least one operating mode determination unit of the control system, the operating mode of the photovoltaic system, wherein in the case that the electrical energy > the specified threshold, the operating mode of the photovoltaic system is the generation mode, and in the case that the electrical energy < the specified threshold, the operating mode of the photovoltaic system is the idle mode.

[0092] Embodiment 14. Method according to one of the three preceding claims, wherein step c) further comprises covering the electrical self-consumption of the photovoltaic system entirely from the direct current generated in the photovoltaic module.

[0093] Embodiment 15. Method according to one of the four preceding claims, wherein step d) comprises: d1) Determining whether the energy from the energy storage is sufficient to fully cover the electrical self-consumption of the photovoltaic system;

[0094] d2) if the energy from the at least one energy storage system is sufficient to fully cover the electrical self-consumption of the photovoltaic system: Covering the electrical self-consumption completely by electrical energy from the energy storage system;

[0095] d3) if the energy from the energy storage is insufficient to fully cover the electrical self-consumption of the photovoltaic system: Covering part of the electrical self-consumption of the photovoltaic system by means of electrical energy from the energy storage and covering the remainder of the electrical self-consumption of the photovoltaic system by means of electrical energy absorbed through the grid interface.

[0096] Brief description of the figures: Further details and features will become apparent from the following description of exemplary embodiments, particularly in conjunction with the dependent claims. The respective features can be implemented individually or in combination with one another. The invention is not limited to the exemplary embodiments. The exemplary embodiments are shown schematically in the figures. Identical reference numerals in the individual figures denote identical or functionally equivalent elements, or elements that correspond to one another with respect to their functions.

[0097] Specifically, we show:

[0098] Figure 1 shows a generation and load profile of a state-of-the-art photovoltaic system;

[0099] Figures 2 and 3 show different embodiments of a photovoltaic system according to the present invention in schematic representation;

[0100] Figure 4 shows a generation and load profile of an embodiment of a photovoltaic system according to the present invention;

[0101] Figures 5 and 6 flowcharts of different embodiments of a method for operating a photovoltaic system according to the present invention;

[0102] Figure 7 shows an embodiment of a photovoltaic system according to the present invention in generation mode; and

[0103] Figure 8 shows a flowchart of an embodiment of a method for operating a photovoltaic system according to the present invention.

[0104] Description of the exemplary implementations

[0105] Figure 1 shows a generation and load profile of a conventional, state-of-the-art photovoltaic system. The abscissa (110) represents time in hours, and the ordinate (112) represents the power output of the photovoltaic system in kW. It is particularly noticeable that between 6 a.m. and 6 p.m., i.e., during daylight hours when sunlight can reach the photovoltaic system, the system's power output is positive. Conversely, before 6 a.m. and after 6 p.m., i.e., during nighttime hours when sunlight cannot reach the photovoltaic system, the system's power output is negative. The maximum power output of the photovoltaic system, i.e., the maximum energy generated by the photovoltaic system, is marked "P1" on the ordinate. For example, this maximum power output corresponds to the connection power agreed upon with a grid operator at the photovoltaic system's grid interface.The operating equipment, such as power cables, transformers, transfer stations, feed-in substations, etc., of the public grid, as well as the grid interface of the photovoltaic system, are designed for this maximum output of the photovoltaic system. Furthermore, it is particularly evident that a conventional photovoltaic system draws electrical energy from the public electricity grid between midnight and 6 a.m., feeds electrical energy into the public electricity grid between 6 a.m. and 6 p.m., and draws energy from the public electricity grid between 6 p.m. and midnight. The negative power figure can specifically indicate the photovoltaic system's own electrical consumption, which is drawn from the upstream grid, for example, at night. The system must draw electrical energy from the public electricity grid.

[0106] Figures 2 and 3 show various embodiments of a photovoltaic system 114 according to the present invention in schematic representation. The photovoltaic system 114 comprises:

[0107] at least one photovoltaic module 116 set up for generating electrical energy in the form of direct current from solar energy;

[0108] at least one inverter 118 is installed for converting the direct current (DC) generated by the photovoltaic module 116 into alternating current (AC) and for outputting the alternating current (AC); at least one transformer 120 is installed for converting the alternating current (AC) output by the inverter 118 into an output alternating current (AC2) of a specified voltage, in particular a voltage specified for a public electricity supply network 130; at least one energy storage device 122 is installed for intermediate storage of electrical energy; at least one, in particular exactly one, grid interface 128 is installed for connecting the photovoltaic system 114 to a public electricity supply network 130, in particular to a low-voltage network, for example having an alternating voltage in the range of 50 V to 1,000 V, or a medium-voltage network, for example having an alternating voltage in the range of 1,001 V to 35 V.000 V, high-voltage network, for example having an alternating voltage in the range of 35,001 V to 110,000 V, and extra-high-voltage network, for example having an alternating voltage in the range of greater than or equal to 110,001 V, wherein the photovoltaic system 114 is set up to supply and / or receive electrical energy via the network interface 128;

[0109] at least one 124 control unit has been set up.

[0110] • in order to cover at least part of the electrical energy required by the photovoltaic system 114 during an idle mode using the electrical energy from the energy storage unit 122, and

[0111] • to limit the output of the electrical energy generated in the photovoltaic module 116 via the grid interface 128 to a predetermined maximum value in a generation mode of the photovoltaic system 114, and to temporarily store any electrical energy generated beyond this limit in the photovoltaic module 116 in the energy storage device 122. Optionally, the photovoltaic system 114 can have additional transformers 120 for converting an input alternating current into an output alternating current with a different voltage than the input alternating current. For example, a transformer 120 can be assigned to the at least one energy storage device 122, in particular arranged such that a voltage applied to a busbar 126, for example, enclosed by the photovoltaic system 114, is converted by the transformer 120 into a voltage of the energy storage device 122.Furthermore, the photovoltaic system 114 may, for example, have an additional transformer 120 between the busbar 126 and the grid interface 128. In particular, the presence of the transformer 120 between the grid interface 128 and the other components of the photovoltaic system 114 may depend, for example, on the type of electricity supply network 130. Thus, if the electricity supply network 130 is a low- or medium-voltage network, a transformer 120 between the busbar 126 and the electricity supply network 130 may not be necessary. However, if the electricity supply network 130 is a high- or extra-high-voltage network, a transformer 120 may be installed between the busbar 126 and the electricity supply network 130.For example, the photovoltaic system 114 shown in Figure 2 can be a photovoltaic system 114 which is set up for feeding into a medium voltage network, whereas the photovoltaic system 114 shown in Figure 3 can be a photovoltaic system 114 which is set up for feeding into a high voltage network.

[0112] For example, the photovoltaic system 114 can have several energy storage devices 122. In particular, the photovoltaic system 114 can be configured to use a combination of several different battery technologies, for example, a combination of different storage durations from different electrical energy storage devices, a combination of different response times of the different electrical energy storage devices.

[0113] In particular, the photovoltaic system 114 can, for example, have more than one energy storage device 122, for instance, two energy storage devices 122. In this case, the photovoltaic system 114's own electrical demand in idle mode can be covered by a first energy storage device 122, while in generation mode, any portion of the electrical energy generated in the photovoltaic module 116 that exceeds the maximum value can be temporarily stored, for example, in a second energy storage device 122. Such an embodiment of the photovoltaic system 114 is shown by way of example in Figure 3. Alternatively, the coverage of the system's own demand in idle mode and the temporary storage of the electrical energy generated in excess of the maximum value can be achieved in a single, for example, a shared, energy storage device 122. Such an embodiment of the photovoltaic system 114 is shown by way of example in Figure 2.

[0114] In particular, the direct current generated in the at least one photovoltaic module 116, for example in the form of a photovoltaic panel, can be converted into alternating current by the inverter 118 and subsequently transformed to a higher voltage level by at least one transformer 120, in particular by the transformer 120 electrically connected to the inverter 118, and fed into the upstream electrical grid 130. Some active components of the photovoltaic system 114, for example inverter 118, control units of the control system 124 and control technology equipment, may require electrical energy for their operation, which is considered the electrical self-consumption of the photovoltaic system 114. Further energy losses, which are attributed to the electrical self-consumption of the overall system, may occur in the operating equipment, such as power cables and transformers 120.Power cables, especially both AC and DC power cables, can experience load-dependent transmission losses. Transformers 120 can also experience load-dependent losses, so-called copper losses, which arise primarily from the electrical resistance of the transformer's windings, as well as load-independent losses, so-called iron losses, which mainly occur in the transformer's magnetic core. In particular, load-independent losses of equipment can occur in every operating mode of the photovoltaic system 114, including, for example, no-load mode, such as low partial load operation, and / or grid feed-in mode.

[0115] The control unit 124 of the photovoltaic system 114 can, for example, be configured to cover the remaining electrical demand of the photovoltaic system 114 by means of electrical energy absorbed through the grid interface 128 in the case that the energy from the energy storage unit 122 is insufficient to fully cover the electrical demand of the photovoltaic system 114 in idle mode.

[0116] Alternatively or additionally, the control unit 124 of the photovoltaic system 114 can, for example, be set up to release the electrical energy temporarily stored in the energy storage unit 122 in the generation mode, in particular the electrical energy generated in the photovoltaic module 116 in excess of the specified maximum value and temporarily stored in the energy storage unit 122, to the public electricity supply network 130 via the grid interface 128 in a subsequent idle mode.

[0117] Figure 4 shows an exemplary generation and load profile of an embodiment of a photovoltaic system 114 according to the present invention over a daily cycle. The abscissa 110 represents time in hours, particularly in daylight hours, and the ordinate 112 represents the electrical power of the photovoltaic system 114 in kilowatts (kW). The positive power, i.e., positive energy of the energy generation, of the photovoltaic system 114 represents the feed-in of the energy generated by the photovoltaic system 114 into the upstream grid 130.In comparison to the generation and load profile of known photovoltaic systems shown in Figure 1, which is illustrated by the dashed line in Figure 4, it can be seen that the photovoltaic system 114 according to the invention only supplies power to the electricity supply network 130 via the grid interface 128 up to a maximum value which is designated “P2”, where “P2” is lower than a maximum achievable power which is designated by “P1”. The electrical energy generated by the photovoltaic system 114 above the specified maximum value “P2” is temporarily stored in the energy storage system 122 and is illustrated in Figure 4 by the hatched area between the curves.The energy temporarily stored in the energy storage unit 122 can be used, for example, to cover the photovoltaic system's own electricity needs during the time the photovoltaic system is in idle mode, i.e., between 6 p.m. and 6 a.m. in the diagram shown in Figure 4. This can, for example, lead to no energy being drawn from the public electricity grid 130 between 6 p.m. and midnight, as shown in the diagram in Figure 4. In particular, energy can only be drawn from the public electricity grid 130 after the energy temporarily stored in the energy storage unit 122 has been depleted, i.e., after midnight in the embodiment shown here, i.e., between midnight and 6 a.m.

[0118] Figures 5 and 6 show flowcharts of different embodiments of a method for operating a photovoltaic system 114 according to the present invention.The method comprises the following steps: a) (identified by reference numeral 132) Provision of a photovoltaic system 114 comprising at least one photovoltaic module 116 configured for generating electrical energy in the form of direct current from solar energy, at least one inverter 118 configured for converting the direct current generated by the photovoltaic module 116 into alternating current and for outputting the alternating current, at least one transformer 120 configured for converting the alternating current output by the inverter 118 into an output alternating current of a specified voltage, in particular a voltage specified for a public electricity supply network 130, at least one energy storage device 122 configured for intermediate storage of electrical energy, at least one grid interface 128 configured for connecting the photovoltaic system to the public electricity supply network 130, at least one control unit 124;.

[0119] b) (identified by reference numeral 134) Determine, using the control unit 124 of the photovoltaic system 114, whether the photovoltaic system 114 is in idle mode or in generation mode; c) (identified by reference numeral 136) If the photovoltaic system 114 is in generation mode: Feed in, in particular optionally, using the control unit 124, into the energy storage system 122 of the photovoltaic system 114 and / or via the grid interface 128 into the public electricity supply network 130 of electrical energy generated in the photovoltaic module 118, wherein the feed-in via the grid interface is limited to a predetermined maximum value by means of the control unit, and any electrical energy generated in the photovoltaic module beyond this value is temporarily stored in the energy storage system;

[0120] d) (identified by reference numeral 138) If the photovoltaic system is in idle mode:

[0121] Ceilings, by means of the control, of the electrical self-consumption at least partially by means of electrical energy from the at least one energy storage device.

[0122] Step d) of the procedure may, for example, include the following steps:

[0123] d1) (identified by reference numeral 140) Determine whether the energy from the energy storage unit 122 is sufficient to fully cover the electrical self-consumption of the photovoltaic system 114;

[0124] d2) (identified by reference numeral 142) if the energy from the energy storage unit 122 is sufficient to fully cover the electrical self-consumption of the photovoltaic system 114: Covering the electrical self-consumption completely with electrical energy from the energy storage unit 122; d3) (identified by reference numeral 144) if the energy from the energy storage unit 122 is insufficient to fully cover the electrical self-consumption of the photovoltaic system 114: Covering part of the electrical self-consumption of the photovoltaic system 114 with electrical energy from the energy storage unit 122 and covering the remainder of the electrical self-consumption of the photovoltaic system 114 by means of electrical energy absorbed through the grid interface 128.

[0125] Figure 7 shows an embodiment of a photovoltaic system 1141m in generation mode. In particular, the energy flow in generation mode of the electrical energy generated in the photovoltaic module 116 is shown by arrows. In generation mode, for example, electrical energy is supplied to the electricity supply network 130 via the grid interface 128 until the predetermined maximum value P2 is reached; this energy flow is illustrated by the left arrow. As soon as the predetermined maximum value P2 is exceeded, the energy flow is redirected, for example by means of the controller 124, so that the electrical energy generated in the at least one photovoltaic module 116 is temporarily stored in the energy storage device 122; this energy flow is illustrated by the right arrow.

[0126] Figure 8 shows a flowchart of an embodiment of a method for operating a photovoltaic system 114 according to the present invention. For example, between the provision of the photovoltaic system in step a) 132 and an end 146 of the method, step b) 134 of the method can first be carried out, for example comprising checking whether energy generation is taking place by the photovoltaic system 114.

[0127] If not, i.e. in idle mode, the electrical self-consumption of the photovoltaic system 114 must be covered (identified by reference numeral 148), which may, for example, entail a check to see if the energy storage unit 122 is charged (identified by reference numeral 150), for example carried out by the control unit 124 of the photovoltaic system 114.If energy is temporarily stored in the energy storage unit 122, in particular step d) 138 can be carried out, optionally including the steps d1) to d3) already carried out above, wherein in the case that the energy temporarily stored in the energy storage unit 122 is not sufficient to cover the own demand of the photovoltaic system 114, the own electrical demand can be partially or completely covered by electrical energy which was taken from the electricity supply network 130 via the grid interface 128, for example by energy procurement via the grid interface 128 (marked by reference symbol 152).

[0128] If, in step b) 134 of the procedure, it is determined by the controller 124 that the photovoltaic system is in generation mode, the energy generated in the photovoltaic system 114, in particular in the photovoltaic module 116 (identified by reference numeral 154), is fed into the grid. The output of the photovoltaic system can be monitored, particularly by the controller 124, and compared with the specified maximum value P2. For example, a query can be made to determine whether the electrical energy currently generated by the photovoltaic system 114 is greater than the specified maximum value P2 (identified by reference numeral 156). As long as the electrical energy currently generated by the photovoltaic system 114 is less than or equal to the specified maximum value P2, steps b) 134 can be repeated and the grid feed-in 154 can continue.As soon as the electrical energy currently generated by the photovoltaic system 114 exceeds the specified maximum value P2, the electrical energy can, for example, be temporarily stored in the at least one energy storage device 122 (identified by reference numeral 158). Following this, a check can be performed, particularly by means of the control unit 124, to determine whether the energy storage device 122 is fully charged (identified by reference numeral 160). If, in particular, the energy storage device 122 has not yet reached its full charging capacity but the specified maximum value P2 has already been exceeded, the power output of the photovoltaic system 114 is reduced (identified by reference numeral 162). (See list of reference numerals.)

[0129] 110 Abscissa

[0130] 112 ordinates

[0131] 114 Photovoltaic system

[0132] 116 photovoltaic modules

[0133] 118 inverters

[0134] 120 transformer

[0135] 122 Energy storage

[0136] 124 Control

[0137] 126 busbar

[0138] 128 Network interface

[0139] 130 public electricity supply network 132 Step a)

[0140] 134 Step b)

[0141] 136 Step c)

[0142] 138 Step d)

[0143] 140 steps d1)

[0144] 142 Step d2)

[0145] 144 Step d3)

[0146] 146 End

[0147] 148 blankets for personal use

[0148] 150 Check energy storage charge level 152 Energy supply via grid interface

[0149] 154 Grid feed-in

[0150] 156 Performance Monitoring

[0151] 158 Charging the energy storage

[0152] 160 Checking the charge level of the energy storage system 162 Power curtailment of the photovoltaic system

Claims

- 28 - Claims 1. Photovoltaic system (114) comprising at least one photovoltaic module (116) set up to generate electrical energy in the form of direct current from solar energy; at least one inverter (118) installed for converting the direct current generated by the photovoltaic module (116) into alternating current and for outputting the alternating current; at least one transformer (120) installed for converting the alternating current output by the inverter into an output alternating current of a specified voltage; at least one energy storage device (122) installed for intermediate storage of electrical energy; at least one grid interface (128) is set up for connecting the photovoltaic system (114) to a public electricity supply network (130), wherein the photovoltaic system (114) is set up to supply and / or receive electrical energy via the grid interface (128); at least one control unit (124) is set up • to cover at least part of the photovoltaic system's own electrical demand (114) in idle mode with the electrical energy from the energy storage unit (122), and • to limit the output of the electrical energy generated in the photovoltaic module (116) via the grid interface (128) to a predetermined maximum value (P2) in a generation mode of the photovoltaic system (114) and to temporarily store any additional electrical energy generated in the photovoltaic module (116) in the energy storage device (122).

2. Photovoltaic system (114) according to the preceding claim, wherein the photovoltaic system (114) has at least two energy storage devices (122), wherein the electrical self-consumption of the photovoltaic system (114) in the idle mode of the photovoltaic system (114) is covered from a first of the at least two energy storage devices (122), wherein a proportion of the electrical energy generated in the photovoltaic module (116) exceeding the maximum value (P2) is temporarily stored in a second of the at least two energy storage devices (122).

3. Photovoltaic system (114) according to one of the preceding claims, wherein the electrical self-consumption of the photovoltaic system (114) has both a load-dependent component and a load-independent component.

4. Photovoltaic system (114) according to one of the preceding claims, wherein the electrical self-consumption of the photovoltaic system (114) comprises at least one component selected from the group consisting of: an electrical energy demand of at least one active unit of the photovoltaic system (114), a load-independent or load-dependent electrical loss of equipment of the photovoltaic system (114), an active power of the at least one inverter (118).

5. Photovoltaic system (114) according to one of the preceding claims, wherein the at least one energy storage device (122) comprises at least one electrical energy storage device selected from the group consisting of: sodium-sulfur battery (NaS battery), lithium-ion battery (Li-ion battery), sodium-nickel-chloride battery (NaNICI battery), nickel-zinc battery (NIZn battery), sodium-ion battery (Na-ion battery), redox flow batteries (vanadium redox battery, sodium bromide redox battery, zinc-bromine battery), lead-acid battery, ultracapacitor (supercap).

6. Photovoltaic system (114) according to one of the preceding claims, wherein the control (124) is configured to cover a remainder of the electrical self-consumption of the photovoltaic system (114) by means of electrical energy absorbed through the grid interface (128) in the case that the energy from the energy storage (122) is insufficient to fully cover the electrical self-consumption of the photovoltaic system (114) in the idle mode.

7. Photovoltaic system (114) according to one of the preceding claims, wherein the control system (124) is configured to release the electrical energy temporarily stored in the energy storage system (122) in the generation mode to the public electricity supply network (130) via the grid interface (128) in a subsequent idle mode.

8. Photovoltaic system (114) according to one of the preceding claims, comprising at least one controller (124). • at least one current measuring device is installed to determine the electrical energy generated in the photovoltaic module (116), • at least one comparison logic set up to compare the electrical energy generated in the photovoltaic module (116) with at least one predefined threshold, • at least one operating mode determination unit is set up to determine an operating mode of the photovoltaic system (114), wherein in the case that the electrical energy > the specified threshold, the operating mode of the photovoltaic system (114) is the generation mode, and in the case that the electrical energy < the specified threshold, the operating mode of the photovoltaic system (114) is the idle mode. wherein the control unit (124) is configured to cover the electrical self-consumption of the photovoltaic system (114) in generation mode from the direct current generated in the photovoltaic module (116).

9. Photovoltaic system (114) according to one of the preceding claims, wherein the photovoltaic system (114) comprises a plurality of inverters (118) and photovoltaic modules (116), wherein the number of inverters (118) and photovoltaic modules (116) is the same.

10. Photovoltaic system (114) according to one of the preceding claims, wherein the photovoltaic system (114) comprises at least one busbar (126), wherein the busbar (126) is arranged between the at least one photovoltaic module (116) and the at least one electrical energy storage device (122).

11. Photovoltaic system (114) according to one of the preceding claims, wherein the electrical self-consumption of the photovoltaic system (114) comprises an active power of the at least one inverter (118) in the event of a reactive power requirement by an operator of the public electricity supply network (130).

12. Method for operating a photovoltaic system (114), comprising a) Provision of a photovoltaic system (114) comprising at least one photovoltaic module (116) configured for generating electrical energy in the form of direct current from solar energy, at least one inverter (118) configured for converting the direct current generated by the photovoltaic module (116) into alternating current and for outputting the alternating current, at least one transformer (120) configured for converting the alternating current output by the inverter into an output alternating current of a specified voltage, at least one energy storage device (122) configured for intermediate storage of electrical energy, at least one grid interface (128) configured for connecting the photovoltaic system (114) to a public electricity supply network (130), at least one control unit (124); b) Determine, using the control system (124) of the photovoltaic system (114), whether the photovoltaic system (114) is in an idle mode or in a generation mode; c) If the photovoltaic system (114) is in generation mode: feeding in, by means of the control (124), into the energy storage (122) of the photovoltaic system (114) and / or via the grid interface (128) into the public electricity supply network (130) of electrical energy generated in the photovoltaic module (116), wherein by means of the control (124) the feed-in via the grid interface (128) is limited to a predetermined maximum value (P2), wherein any electrical energy generated in the photovoltaic module (116) beyond this is temporarily stored in the energy storage (122); d) If the photovoltaic system (114) is in idle mode: Cover, by means of the control (124), the electrical self-consumption at least partially by means of electrical energy from the at least one energy storage device (122).

13. A method according to the preceding claim, wherein the photovoltaic system (114) is a photovoltaic system (114) according to one of the preceding claims relating to a photovoltaic system (114).

14. A method according to one of the two preceding claims, wherein step b) comprises: b1) Determine, by means of at least one current measuring device of the controller (124), the electrical energy generated in the photovoltaic module (116); b2) Compare, by at least one comparison logic of the controller (124), the electrical energy generated in the photovoltaic module (116) with at least one predetermined threshold; b3) Determine, by at least one operating mode determination unit of the controller (124), the operating mode of the photovoltaic system (114), wherein in the case that the electrical energy > the predetermined threshold, the operating mode of the photovoltaic system (114) is the generation mode, wherein in the case that the electrical energy < the predetermined threshold, the operating mode of the photovoltaic system (114) is the idle mode.

15. Method according to one of the three preceding claims, wherein step c) further comprises covering the electrical self-consumption of the photovoltaic system (114) entirely from the direct current generated in the photovoltaic module (116).

16. Method according to any one of the four preceding claims, wherein step d) comprises: d1) Determine whether the energy from the energy storage (122) is sufficient to fully cover the electrical self-consumption of the photovoltaic system (114); d2) if the energy from the at least one energy storage device (122) is sufficient to fully cover the electrical self-consumption of the photovoltaic system (114): Covering the electrical self-consumption completely by electrical energy from the energy storage device (122); d3) if the energy from the energy storage (122) is not sufficient to fully cover the electrical self-consumption of the photovoltaic system (114): Covering part of the electrical self-consumption of the photovoltaic system (114) by means of electrical energy from the energy storage (122) and covering the remainder of the electrical self-consumption of the photovoltaic system (114) by means of electrical energy absorbed through the grid interface (128).

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