Method for determining a target value of a charging power for charging a battery of a vehicle by means of a charging device

Abstract

The invention relates to a method for determining a target value of a charging power for charging a battery (32) of a vehicle (30) by means of a charging device (12), wherein the charging device (12) is electrically connectable to a photovoltaic system (14) and a consumer system (20), comprising the following steps: - reading in power information, which represents a difference between actual values ​​of a power provided by the photovoltaic system (14) and a power consumed by the consumer system (20) and a charging power provided by the charging device (12) for charging the battery (32) of the vehicle (30), by means of a computing unit (28); and - Determining the target value of the charging power based on the power information read in by means of the computing unit (28), wherein the determined target value of the charging power represents a surplus of the power provided in order to charge the battery (32) of the vehicle (30) with the determined target value of the charging power by means of the charging device (12), wherein depending on, in particular in the event of unavailability, the power information to be read in - a reference performance information is read in by means of the computing unit (28) and - the target value of the charging power is determined based on the read-in reference power information.

Description

The invention relates to a method for determining a setpoint value of a charging power for charging a battery of a vehicle by means of a charging device, a computing unit, a charging device and a system, and to a corresponding computer program and a storage medium.Prior ArtIn 2020, it has been found that about 89 percent of the roofs in Germany are not yet equipped with their own photovoltaic system. In order to make more use of this potential for generating regenerative energy, the legislator plans that a photovoltaic installation must necessarily be installed both in new buildings and in remanation of old buildings. In addition, in recent years, the legislator has paid several hundred million euros of deliveries to private households, so that corresponding charging devices (so-called wall boxes) for battery-electric vehicles are produced in the private environment. Both measures help to reduce the dependence on fossil fuels. For the joint operation of photovoltaic systems, charging stations and battery-electric vehicles, care should be taken in this context that a high proportion of the available solar energy is actually also used by the vehicle or further electrical devices in private home and not an unnecessarily large amount of energy has to be purchased from the power grid. If a so-called excess of electrical power nevertheless arises, this power is in turn fed into the power grid and quenched and tempered.In the case of excess charging, the situation is considered in which a battery-electric vehicle is connected to the wallbox and does not necessarily have to be charged as quickly as possible. This can be due, for example, to the fact that sufficient residual capacity is present in the battery for imminent short journeys or that the next journey is scheduled only in a few days.Furthermore, the battery of the vehicle should not be fully charged, so that it is still possible to absorb further excess solar energy. In the case of excess charging, the question arises of how exactly the excess of power can be used for charging the battery of the vehicle. For this purpose, there are different strategies which differ in their complexity, in the complexity of implementation and ultimately also in the costs of procurement.In the simplest case, this is a time-based control system in which the charging device is switched on at a specific time and is switched off again a few hours later. During this period, the battery in the vehicle is charged with a constant electric power. It can naturally occur that fluctuations in the solar power generated are not taken into account and, for example, in the event of interruptions due to cloud formation, corresponding electrical power must be purchased. Moreover, an excess of solar energy cannot be fully absorbed by the battery of the vehicle in this simple strategy.If a measuring device is additionally available, with which the generated solar energy and the energy fed into the power grid can be determined, the charging power for the battery-electric vehicle can be very easily adapted and it can then be ensured that the intrinsic consumption is optimized. However, the measuring device generally requires an additional cable connection between the charging device and the measuring device in the switchgear cabinet, which apart from electrical installations in new construction objects often entails a high level of cost for retrofitting.DE 10 2022 203 741A1 discloses a method for determining a setpoint value of a charging power for charging a battery of a vehicle by means of a charging device. The charging device can be electrically connected to a photovoltaic system and a consumer system. In this case, power information representing a difference between actual values of a power provided by the photovoltaic system and a power drawn by means of the consumer system and a charging power provided by means of the charging device for charging the battery of the vehicle is read in. Furthermore, the setpoint value of the charging power is determined based on the power information using a control algorithm, wherein the determined setpoint value of the charging power represents an excess of the provided power in order to charge the battery of the vehicle with the setpoint value of the determined charging power by means of the charging device.Disclosure of the InventionAccording to a first aspect, the present invention relates to a method for determining a setpoint value of a charging power for charging a battery of a vehicle by means of a charging device and / or for charging a battery of a vehicle with a determined setpoint value of a charging power by means of a charging device according to claim 1.The method comprises a step of reading in a piece of power information which represents a difference between actual values of a power provided by the photovoltaic system and a power drawn by means of the consumer system and a charging power provided by means of the charging device for charging the battery of the vehicle. In other words, the power information represents a difference between an actual value of the power provided by the photovoltaic system and an actual value of the power drawn by means of the consumer system and an actual value of the charging power provided by means of the charging device for charging the battery of the vehicle.The method further comprises a step of ascertaining the setpoint value of the charging power based on the power information, in particular using a control algorithm, by means of a computing unit, wherein the ascertained setpoint value of the charging power represents an excess of the provided power in order to charge the battery of the vehicle with the ascertained setpoint value of the charging power by means of the charging device.In this case, as a function of, in particular in the case of unavailability, the power information item to be read in (by means of the arithmetic unit), in particular alternatively, reference power information item is read in by means of the arithmetic unit and the setpoint value of the charging power item is determined, in particular alternatively or further, on the basis of the read-in reference power information item (by means of the arithmetic unit). In other words, the setpoint value of the charging power can be ascertained depending on the power information to be read in, either on the basis of the power information and / or on the basis of the reference power information. The setpoint value of the charging power is preferably determined on the basis of the power information item and independently of the reference power information item when the power information item to be read is available. If the power information item to be read in is not available, the setpoint value of the charging power is preferably determined on the basis of the reference power information item and in particular independently of the difference between the actual values represented by the power information item.The steps of the method, in particular the steps of reading in the performance information and of determining the setpoint value, are preferably carried out repeatedly, preferably cyclically, for example periodically.According to a second aspect, the present invention relates to a computing unit for determining a charging power for charging a battery of a vehicle by means of a charging device according to claim 10.According to a third aspect, the present invention provides a charging device for charging a battery of a vehicle according to claim 11.According to a fourth aspect, the present invention provides a system for charging a battery of a vehicle according to claim 12.According to a further aspect, the present invention relates to a computer program and a machine-readable storage medium.The vehicle comprises a battery which is designed to supply a drive unit, in particular an electric motor, of the vehicle at least partially with electrical energy. It is conceivable that the vehicle is a battery-electric vehicle or a hybrid vehicle. The vehicle can be a land vehicle, an aircraft or a watercraft. For example, the vehicle is a car, a truck, an e-bike, an electrically driven helicopter or an electrically driven boat.The vehicle comprises a charging interface which is electrically connectable to a charging interface of the charging device in order to charge or discharge the battery of the vehicle.The charging device comprises at least one further charging interface in order to connect the charging device indirectly or directly to the photovoltaic system and / or the consumer system. The charging device is preferably designed as a wall box. It is conceivable that the charging device is arranged on an infrastructure element or a building.The photovoltaic system includes one or more photovoltaic modules and an inverter. The photovoltaic modules are arranged, for example, on a roof of a building. The photovoltaic system is designed to provide electrical power generated by the photovoltaic modules and converted into alternating current by means of the inverter. The photovoltaic system can also include one or more electrical storage units, for example. Battery storage devices comprise battery storage devices which are designed to absorb or remove power provided, in particular, by photovoltaic modules of the photovoltaic system and to store it temporarily. The storage unit of the photovoltaic system is designed to provide the stored electrical energy to the charging device.The consumer system comprises one or more consumers different from the vehicle, which are preferably arranged on or in the building. The load system can also include one or more electrical storage units, for example. Battery storage devices comprise which are designed to absorb or draw off and store power provided in particular by the photovoltaic system. The storage unit of the consumer system is designed to provide the stored electrical energy to the charging device.Preferably, the charging device, the photovoltaic system and the consumer system are electrically connectable or connected indirectly to one another by means of a distributor unit arranged in particular on or in the building.An excess of provided power can be understood to mean a difference between the power provided by the photovoltaic system or the solar power and the power drawn by means of the consumer system or the consumer power, wherein the difference is preferably positive.An actual value of a power can be understood in the context of the present application as a current value of the power. In the context of the present application, a setpoint value of a power can be understood to mean a determined value of the power into which the actual value of the power is to be converted or is converted, in particular in the sense of a regulation.Reading in the power information is preferably preceded by a step of sensorially detecting or measuring the difference between the actual values of the power provided by the photovoltaic system and the power drawn by means of the consumer system and the charging power provided by means of the charging device for charging the battery of the vehicle. It is conceivable that the difference is detected or measured, for example, at an interface to an electrical supply network. For example, the difference can be detected as a power output to the electrical supply grid or provided by the electrical supply grid.Alternatively or additionally, in the step of sensorially detecting or measuring, the actual value of the power provided by the photovoltaic system, the actual value of the power drawn by means of the consumer system and the actual value of the charging power provided by means of the charging device for charging the battery of the vehicle can be detected or measured in order to determine or calculate the difference based on the detected actual values. The powers or the power difference can be detected or measured, for example, by means of one or more electrical power measurement units.The power information item is in particular a digital or analog signal which represents the difference between the actual values of the power provided by the photovoltaic system and the power drawn by means of the consumer system and the charging power provided by means of the charging device for charging the battery of the vehicle.According to a preferred embodiment, the difference between the actual values and / or the actual values are transmitted to the computing unit by means of a wireless communication link. Here, the reading in of the power information can comprise receiving the difference between the actual values transmitted using the wireless communication connection and / or receiving the actual values transmitted using the wireless communication connection. The wireless communication connection can comprise, for example, a mobile radio connection and / or a WiFi connection.When transmitting the difference between the actual values and / or the actual values using a wireless communication link, an availability of the transmitted values or data depends on a quality of service, for example represented by a stability or reliability, a minimum bandwidth, etc. If a minimum bandwidth fails or falls below it, the power information to be read in cannot be provided to the arithmetic unit. According to the present approach, therefore, in particular in the case of unavailability of the performance information item to be read in, the reference performance information item can be read in by means of the arithmetic unit in substitute fashion or instead of the performance information item. In other words, the reference performance information is preferably read in exactly in the case where the performance information is not available to the computing unit.The power information is (not) available to the computing unit when it is possible to read in the power information by means of the computing unit (not), in particular when the power information can be read in or called up or received by means of the computing unit (not). It is conceivable that an error in the data transmission and / or data storage also causes unavailability of the performance information. Therefore, the reference performance information is read in alternatively to the computing unit preferably in the case of non-availability, in particular in the case of failure, of a wireless communication connection for transmitting the difference between the actual values and / or the actual values.Here, the reading in of the performance information can comprise a check of an availability of the performance information. In other words, in the step of reading in, availability or unavailability of the performance information can be checked or checked. The step of reading in can therefore comprise a determination of an unavailability of the performance information item. In this sense, the read-in performance information can represent information about an unavailability of the performance information.Alternatively or additionally, the reference performance information can also be read in in addition to the performance information in order to plausibilize the read-in performance information using the reference performance information. It is conceivable that the setpoint value of the charging power is determined based on the power information if the power information deviates from the reference power information by less than a predefined maximum value. It is furthermore conceivable that the setpoint value of the charging power is determined based on the reference power information if the power information deviates from the reference power information by at least the predefined maximum value. As a result, implausible differences of actual values represented by the performance information can be recognized and ignored when determining the setpoint value.Thus, reading in the reference performance information as a function of the performance information to be read in can be understood to mean a dependence on an availability or presence of the performance information for the computing unit and / or a dependence on a value, in particular a plausibility of the value, of the difference of the actual values represented by the performance information and / or, in particular a plausibility, of the actual values.The reference power information can be read out from a storage unit assigned to the arithmetic unit or from a storage medium assigned to the arithmetic unit. The storage unit is preferably connected to the computing unit by means of a wired communication connection.The computing unit can have one or more hardware and / or software interfaces in order to read in or receive the performance information and / or the reference performance information. The computing unit can have one or more hardware and / or software modules in order to determine or calculate the setpoint value of the charging power. The computing unit can have a hardware and / or software interface in order to output a signal with information regarding the determined setpoint value of the charging power.The computing unit can be arranged on the charging device, in particular integrated into the charging device. The computing unit can also be arranged away from the charging device, for example within a building or on or in the vehicle, or can be part of a cloud computing environment. The computing unit arranged away from the charging device can be connected, in particular connected, wirelessly or by wire to the charging device in order to transmit an analog or digital signal with information regarding the determined setpoint value of the charging power to the charging device. The computing unit is preferably communicatively connectable, in particular connected, to the photovoltaic system and / or the consumer system directly or indirectly, for example via a server backend, by means of a wireless communication connection.By means of the method according to the invention and the devices according to the invention, it is now possible to provide a charging strategy for charging a vehicle battery, according to which charging strategy the excess power actually present for charging can be approximated efficiently even in the case of unavailability and / or implausibility of actual values of the solar power, the load power and / or the charging power. As a result, the power provided by means of a photovoltaic system can be exploited to the best possible extent and additional power consumptions from a supply grid or additional feeds into the supply grid can be minimized.Advantageously, the reference power information represents a reference difference between a power provided by the photovoltaic system and a power drawn by means of the consumer system and a charging power provided by means of the charging device for charging the battery of the vehicle. The reference difference is in particular a difference determined independently of the difference represented by the performance information.In this case, it is advantageous if the reference performance information item hasa first reference value for the power provided by the photovoltaic system,a second reference value for the power drawn by means of the consumer system, andthe actual value of the charging power provided by means of the charging device for charging the battery of the vehicle.It is conceivable that the actual value of the power provided by the photovoltaic system and / or the actual value of the power drawn by means of the consumer system is transmitted or is to be transmitted to the computing unit by means of a wireless communication connection, and the actual value of the charging power provided by means of the charging device for charging the battery of the vehicle is transmitted to the computing unit by means of a wired communication connection. If the wireless communication connection is not available (and the wired communication connection is available), only the actual value of the charging power, but not the actual values of the power provided by the photovoltaic system and the power drawn by means of the consumer system, can be provided to the computing unit.According to this embodiment, the reference power information can be determined as the difference between the first reference value for the power provided by the photovoltaic system and the second reference value for the power drawn by means of the consumer system and the actual value of the charging power provided by means of the charging device for charging the battery of the vehicle. By providing the first and second reference values, the setpoint value of the charging power can be reliably determined even in the event of partial non-availability or implausibility of the actual values of the powers.Alternatively, it is advantageous here if the reference performance information item hasa first reference value for the power provided by the photovoltaic system, anda second reference value for a sum of the power drawn by means of the consumer system and the charging power provided by means of the charging device for charging the battery of the vehicle.It is conceivable that the actual value of the power provided by the photovoltaic system and / or the actual value of the power drawn by means of the consumer system and / or the actual value of the charging power provided by means of the charging device for charging the battery of the vehicle is transmitted or is to be transmitted to the computing unit by means of a wireless communication connection, for example when the computing unit is part of a cloud computing unit or a server backend. If the wireless communication connection is not available, the actual values of the powers cannot be provided to the computing unit.According to this embodiment, the reference power information can be determined as the difference between the first reference value for the power provided by the photovoltaic system and the second reference value for the sum of the power drawn by the consumer system and the charging power provided by the charging device for charging the battery of the vehicle. By providing the first and second reference values, the setpoint value of the charging power can be reliably determined even if the actual values of the powers are not available or implausibility is not present.It is also advantageous if the reference performance information depends on a time of day, in particular further on a day of the week and / or a month, and the reference performance information to be read in is selected taking into account a current time of day, in particular further on a current day of the week and / or a current month. It is conceivable that a reference difference and / or a first and a second reference value are provided to the computing unit for a plurality of predefined times of day, in particular for a plurality of predefined combinations of times of day and / or days of week and / or months.Here, the reading in of the reference performance information can comprise a reading out of the reference performance information from a storage unit assigned to the computing unit as a function of a current time, furthermore as a function of a current day of the week and / or a current month. Preferably, the reference performance information is read out from the memory unit for which an associated time and / or an associated day of the week and / or an associated month deviates / deviates minimally from the current time and / or the current day of the week and / or the current month. This configuration makes it possible to take account of time-of-day-dependent, day-of-week-dependent and / or month-dependent variations in the power provided by the photovoltaic system, the power drawn by means of the consumer system and / or the charging power when determining the setpoint value.It is also advantageous if the read-in reference performance information item is stored.measured values of the power provided by the photovoltaic system and / or of the power drawn by means of the consumer system and / or of the charging power provided by means of the charging device for charging the battery of the vehicle and / ora model of the photovoltaic system and / or of the consumer system and / or of the charging devicebased. The measured values can be, for example, the actual values of the solar power and / or of the consumer power available when the power information is available and / or the actual values of the charging power. The reference performance information can be determined or calculated based on the measured values before and / or during the runtime of the method.The model may be a statistical and / or physical and / or self-learning model. The model may include one or more sub-models. According to one specific embodiment, a first submodel represents the solar power and a second submodel represents the consumer power or the charging power or the sum of the consumer and the charging power. It is also conceivable for the model to represent the difference between the solar power and the sum of the load power and the charge power. The model preferably comprises a time-of-day and / or day-of-week and / or month-dependent reference performance information. The model preferably comprises a look-up table which assigns a value of the reference power to discrete times or time ranges.This configuration makes it possible to provide reference performance information which is sufficiently accurate for most operating situations with a manageable implementation outlay.It is furthermore advantageous if the reference performance information stored in a storage unit assigned to the computing unit and / or the first and / or second reference value stored in a storage unit assigned to the computing unit is updated or adapted based on the actual values when the performance information is available. In other words, this means that the reference value or values for the power provided by the photovoltaic system and / or the reference values for the power drawn by means of the consumer system are adjusted using the actual values of the power provided by the photovoltaic system or the actual values of the power drawn by means of the consumer system. As a result of this configuration, when the actual values are available, they can be used to further improve the model, in particular to reduce a deviation between the model and the actual values.It is advantageous if the setpoint value of the charging power is determined using a control algorithm, in particular comprising a controller with an integral component. The control algorithm is configured to control the difference between the actual values of the power provided by the photovoltaic system and the power drawn by means of the consumer system and the charging power provided by means of the charging device for charging the battery of the vehicle to a predefined setpoint value, preferably zero, in order to import as far as possible no power from a supply network for charging the battery of the vehicle. The determination of the setpoint value of the charging power based on the read-in power information using a control algorithm is preferably a calculation of the charging power as a function of the difference between the actual values. Depending on a quality of the control algorithm, the charging power determined can deviate from an actually present excess of power.The control algorithm preferably comprises a controller with an integral component. For example, the controller may be an integral controller, a proportional-integral controller, or a proportional-integral-differential controller. As a result, the control algorithm is set up to control to the predefined setpoint value as exactly as possible.It is advantageous if the control algorithm is set up to determine the setpoint value of the charging power taking into account at least one charging property of the charging device, wherein the at least one charging property is selected from: maximum charging power of the charging device, predefined charging power levels of the charging device. Preferably, both the maximum charging power of the charging device as a first charging property and predefined charging power levels of the charging device as a second charging property are taken into account when ascertaining the charging power. Taking into account the maximum charging power of the charging device can comprise reducing the ascertained charging power to the maximum charging power if the ascertained charging power is greater than the maximum charging power. Taking into account the predefined charging power levels of the charging device can comprise increasing or reducing the ascertained charging power to that of the predefined charging power levels which deviates positively or negatively minimally from the ascertained charging power. As a result of this configuration, typical non-linear features of the charging device such as, for example, already when determining the setpoint value of the charging power can be detected. This is because power constraints and quantization steps for voltage and charging current can be taken into account.It is advantageous here if the control algorithm comprises a charging device model with an anti-wind-up feedback in order to take into account the at least one charging property of the charging device when determining the setpoint value of the charging power. The anti-wind-up feedback is preferably configured to subtract a difference between an input variable of a charging device model representing the at least one charging property of the charging device and an output variable of the charging device model from an input variable of a controller of the control algorithm. This configuration allows the control quality to be significantly improved and power drain / drain from the supply grid to be further reduced.It is furthermore advantageous if the method comprises a step of charging the battery of the vehicle with the determined setpoint value of the charging power by means of the charging device, wherein, in particular only then,the charging device is provided with additional power by means of a power supply unit if the determined setpoint value of the charging power is greater than a difference between the power provided by the photovoltaic system and the power drawn by means of the consumer system, orproviding additional power by means of the charging device to a power take-off unit if the determined setpoint value of the charging power is smaller than the difference between the power provided by the photovoltaic system and the power taken off by means of the consumer system.In other words, in the case that the determined setpoint value of the charging power, which represents a mathematically determined available excess of power provided by the photovoltaic system, deviates from the actually available excess, or no excess at all is present, either additional power can be provided from the power supply unit to the charging device or power can be provided from the charging device to the power take-off unit. The power consumption unit and / or power consumption unit can be a local storage unit, for example an electrical storage unit such as a battery. It is also conceivable for the power consumption unit and / or power take-off unit to be designed as an electrical supply network, fed by one or more power plants. This configuration ensures that the vehicle is actually charged with the determined setpoint value of the charging power, regardless of whether the actual excess of power corresponds to the determined excess of power.A computer program product or computer program with program code which can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used for carrying out, implementing and / or controlling the steps of the method according to one of the embodiments described above is also advantageous, in particular if the program product or program is executed on a computer or a computing unit.The invention will be explained in more detail below with reference to the drawings.This is shown by FIG. 1 shows a schematic illustration of an electrical network for a photovoltaic surplus charging of a vehicle; FIG. 2 shows a block diagram of a controlled system according to one specific embodiment; FIG. 3 is a block diagram of a control circuit according to an embodiment; FIG. 4 shows a block diagram of a further control circuit according to one embodiment; FIG. 5 shows a schematic illustration of models for the solar power and the consumer power; and FIG. 6 shows a flow chart of a method for ascertaining a charging power for charging a battery of a vehicle.FIG. 1 shows a schematic illustration of an electrical network which enables photovoltaic excess charging of a battery-electric vehicle 30, for example on a residential building 10.A charging device 12 designed as a wallbox 12, a photovoltaic system 14 with photovoltaic modules 16 and an inverter 18, and a consumer system 20 with one or more electrical consumers are arranged on the residential building 10. Furthermore, the residential building 10 comprises an electrical distribution unit 22.The photovoltaic system 14 is designed to provide electrical power generated by the photovoltaic modules 16 and converted into alternating current by means of the inverter 18 to the consumer system 20, the charging device 12 and / or to a supply grid 26 electrically connecting the residential building 10 to a power plant. For this purpose, the distributor unit 22 comprises a plurality of electrical interfaces which are designed to enable an electrical connection between the distributor unit 22 and the inverter 18, between the distributor unit 22 and the consumer system 20, between the distributor unit 22 and the charging device 12 and between the distributor unit 22 and the supply network 26. According to the present exemplary embodiment, the charging device 10 is electrically connected indirectly via the distributor unit 22 to the photovoltaic system 14 and the consumer system 20.The charging device 12 is assigned a computing unit 28, which can be arranged on the charging device 12, in particular integrated into the charging device 12. According to the present embodiment, the computing unit 28 is connected to the inverter 18 of the photovoltaic system 14 or to an electrical current sensor arranged on the photovoltaic system 14 by means of a wireless communication connection, for example a mobile radio connection or a WiFi connection. In addition, the computing unit 28 is connected by means of a further wireless communication connection, for example a mobile radio connection or a WiFi connection, to an electrical current sensor, not shown, at a house connection point of the residential building 10. By means of the wireless communication connections, actual values of a power provided by the photovoltaic system 14 and a difference of actual values of a power drawn by means of the consumer system 20 and a charging power provided by means of the charging device 12 for charging the battery 32 of the vehicle 30 can be provided to the computing unit 28.The arithmetic unit 28 is configured to ascertain a setpoint value of a charging power for charging a battery 32 of the vehicle 30 by means of the charging device 12. For this purpose, the computing unit 28 comprises a processor, a storage medium with a computer program, and at least one communication interface. The computer program includes instructions that, when executed by the processor, cause the target charge power value to be determined for charging the battery 32 of the vehicle 30 according to the method described below.For this purpose, the arithmetic unit 28 is configured to read in power information relating to a difference between an actual value of a power provided by the photovoltaic system 14 and an actual value of a power taken off by means of the consumer system 20 and an actual value of a charging power provided by means of the charging device 12 for charging the battery 32 of the vehicle 30. Furthermore, the arithmetic unit 28 is configured to determine the setpoint value of the charging power on the basis of the read-in power information. In this case, the determined setpoint value of the charging power represents an excess of the power provided in order to charge the battery 32 of the vehicle 30 with the determined setpoint value of the charging power by means of the charging device 12.In addition, the computing unit 28 is configured to read in reference power information as a function of, in particular in the case of unavailability, the power information to be read in and to determine the setpoint value of the charging power on the basis of the read-in reference power information.FIG. 2 shows a block diagram of a controlled system 34 on which the charging of the vehicle 30 with the ascertained charging power is based. the controlled system 34 is assigned the charging power P batt,ref ascertained by means of the arithmetic unit 28 as a control variable or control intervention and a power P grid provided to the supply network 26 or taken off by means of the supply network or exported into the supply network as a controlled variable or control intervention.In this case, the power P grid, which is exported into the supply grid 26 or imported from the supply grid 26, corresponds, in a simplified manner, to a difference between a power P solar provided by the photovoltaic system 16 and the charging power P batt, by means of which the battery 32 of the vehicle 30 is charged, and the power P consumer, which is drawn from the load system 20 and corresponds to the current consumption of all further electrical devices of the residential building 10:Furthermore, the controlled system 34 takes into account a first charging property 36 of the charging device 12 and a second charging property 38 of the charging device 12.The first charging property 36 represents a maximum charging power of the charging device 12, which can be provided at a maximum by the charging device 12 for charging the battery 32 of the vehicle 30, for example. 11 kW. The charging device 12 is configured to charge the battery 32 of the vehicle 30 with the maximum charging power if the ascertained charging power P batt,ref exceeds the maximum charging power.It is also conceivable for the first charging property 36 additionally to represent a maximum negative charging power of the charging device 12, which can be absorbed at a maximum by the battery 32 of the vehicle 30 by means of the charging device 12 and made available to the consumer system 20. In this way, using the control algorithm presented, a power drawn from the load system 20 can alternatively or additionally be supplied to the photovoltaic system 14 also from the battery 32 of the vehicle 30, if not enough solar power is available.The second charging property 38 represents predefined charging power levels of the charging device 12, according to which the charging power which can be provided for charging the battery 32 of the vehicle 30 is discretized, for example. 1.4 kW, 3.7 kW, 7.4 kW, 11 kW. The charging device 12 is configured to charge the battery 32 of the vehicle 30 with a charging power which deviates minimally in terms of amount or positive or negative from the ascertained charging power.That is, in other words, the controlled system 34 takes into account typical non-linear features of the charging device 12, such as power constraints and quantization steps for voltage and charging current. The non-linear properties of the charging device 12 or wallbox 12 preferably comprise a quantization of the charging current or the charging power and a lower limit at zero (i.e. no feedback from the vehicle 30 into the charging device 12 or into an electrical network of the residential building 10) and an upper limit which is given by an electrical design of the charging device 12.FIG. 3 shows a block diagram of a control circuit according to an embodiment. The control loop is provided in its entirety with the reference numeral 40 and comprises a control algorithm 42 which can be implemented, for example, as software and the control path 34 according to FIG. 2.According to this embodiment, the control algorithm 42 includes an integral controller. It is also conceivable for the control algorithm 42 to comprise an alternative controller having an integral component, for example a proportional-integral controller (PI controller) or a proportional-integral-differential controller (PID controller).The control algorithm 42 is configured to control the controlled variable to a predefined setpoint value, in particular, in order to avoid having to buy power from the supply network 26 as much as possible.It is also conceivable for the controlled variable to be controlled to a predefined setpoint value by means of the control algorithm 42. As a result, the next higher power level of the charging device 12 can be selected, such that the solar power provided by means of the photovoltaic system 14 can be used completely for charging the battery 32 of the vehicle 30 by small amounts of power purchased from the supply grid 26.The control algorithm 42 further includes a boost model 44 with anti-wind up feedback. The charging device model 44 represents at least one charging property of the charging device 12, preferably the first charging property 36 and the second charging property 38 according to FIG. 2.The anti-wind-up feedback is configured to subtract a difference between an input variable of the charging device model 44 and an output variable of the charging device model 44 from an input variable of the integral controller. In other words, an output of the charging device model 44 is subtracted from an input of the charging device model 44 and then again negatively connected to an input of the integrator.Therefore, typical, in particular non-linear, properties or features of the charging device 12 by means of the charging device model 44 and the anti-wind-up feedback can already be explicitly taken into account in the control algorithm 42. This prevents the integral component from continuing to run in the regulator when the charging device 12 is at its power limit, for example. It is also possible in this way that no switching process from a first to a second power stage of the charging device 12 occurs when a value of the manipulated variable lies between two power stages.FIG. 4 shows a block diagram of a further control circuit according to an embodiment. The control circuit is provided in its entirety with the reference symbol 40'.In addition to the charging device 12 or wallbox 12, the inverter 18 and the battery 32, the control circuit 40' comprises a software module 46 and a model 48 of the photovoltaic system 14 assigned to the software module 46.The software module 46 includes a programming interface for the inverter 18. Software module 46 is preferably stored on a computing unit assigned to charging device 12, for example computing unit 28 according to FIG. 1.The model 48 assigned to the software module 46 can likewise be stored on the arithmetic unit assigned to the charging device 12. The model 48 represents a power that is likely to be provided by the photovoltaic system 14, for example as a function of the time of day, the time of year, etc.In this case, the actual value of the power provided by the photovoltaic system 14 detected by the inverter 18 is transmitted to the software module 46 of the charging device 12 by means of a wireless communication connection, for example a WiFi connection. In addition, this transmitted actual value of the solar power is used to improve the model of the photovoltaic system 14 or the power provided by the photovoltaic system 14 at runtime.In other words, in the case of the solution based on radio communication according to this embodiment, it is assumed that the power P solar currently generated by the photovoltaic system 14 or the solar installation 14 and the sum of the two powers from P batt and P consumer can be detected by measurement technology by means of one or more measurement devices and are available in the inverter 18 or an Internet portal assigned to the inverter 18 Consequently, a query can be started on the charging device 12 side in the radio network using a programming interface, with which query the above-mentioned measured values are read repeatedly from the Internet, for example at specific times. Since the controller is intended to keep the power balance stationary at a predefined setpoint value (e.g. close to zero), a controller with an integral component (e.g. I controller, PI controller, PID controller etc.) is recommended for the charging device 12 to determine the setpoint value P batt,ref If the radio network operates reliably and the regular interrogation of the measured values is possible, the controller should operate properly and ensure that the excess of solar energy can be stored in the battery 32 of the electric vehicle 30.In the event that the interrogation of the measured values is not possible, corresponding substitute values or reference values, in particular from a model, are used. This model includes, for example, two submodels in one possible embodiment. The first submodel describes the course of P solar over the time of day with a look-up table. A second submodel describes with a further look-up table the profile of the sum of P batt and P consumer likewise over the time of day. The sub-models are determined using a machine learning algorithm and preferably continuously adjusted.FIG. 5 shows a schematic representation of models for the solar power (FIG. 5A ) and the consumer power (FIG. 5B ), in particular for providing a look-up table, which discrete hours each have a power value P solar or. P is assigned to consumer.The current tag is divided into n time intervals for this purpose. Depending on the number n of time intervals, the error between the actual curve (solid line) of the power over time and the approximated curve (dotted line) can be significantly reduced. However, more memory is then also required in order to implement the method in a computing unit.For each time interval, the average value of the measured solar power P solar or of the load power P consumer is determined. The approximated function of these two variables over time ultimately results, for example, from linear interpolation between the stored mean values. In order to take account of the change of these two curves over the season and at the same time great fluctuations (for example due to weather influences or due to further special events with high energy consumption), various possibilities are known to the person skilled in the art.According to one embodiment, the model is updated at runtime. For this purpose, a suitable weighting of already present power values and the power values obtained at the runtime can be carried out.If such a curve with power values P 1,old, P 2,old, P 3,old etc. for the solar power and / or the consumer power from the past and additionally a new current average value P k,mean is present for a specific time interval k, the average value can be adapted via the following relationship:In this case, the parameter λ represents a tuning factor. Depending on the setting of the parameter λ, the weight can be shifted to either the old values or the new current performance value. Alternatively, the curves for solar power and for consumer power can also be stored for each individual day and mean curves for the following years can be stored, for example, per week. Further variants in the averaging are conceivable.In addition to the approach with the characteristic curve or another similarly constructed data-based model, which can be adapted in real time, in an alternative embodiment a physical model could also be used for the description of the solar power over time. In this case, selected physical parameters may be adjusted in real time.FIG. 6 shows a flow chart of method 100 for ascertaining a setpoint value of a charging power for charging a battery of a vehicle by means of a charging device. The charging device is electrically connectable, in particular connected, to a photovoltaic system and a consumer system.In step 110, a piece of power information is read in, which represents a difference between actual values of a power provided by the photovoltaic system and a power drawn by means of the consumer system and a charging power provided by means of the charging device for charging the battery of the vehicle.Depending on, in particular in the case of unavailability, the performance information item to be read in, alternatively or additionally, a reference performance information item is read in in step 120.In step 130, the setpoint value of the charging power is determined by means of a computing unit, preferably using a control algorithm, wherein the determined setpoint value of the charging power represents an excess of the power provided. In this case, the setpoint value of the charging power is determined on the basis of the read-in power information and / or on the basis of the read-in reference power information.In step 140, the battery of the vehicle is charged with the ascertained setpoint value of the charging power by means of the charging device. In particular, additional power is provided to the charging device by means of a power supply unit when the setpoint value of the determined charging power is greater than a power difference between a power provided by the photovoltaic system and a power drawn by means of the consumer system. Alternatively, additional power is provided to a power take-off unit by means of the charging device if the determined setpoint value of the charging power is smaller than the power difference between the power provided by the photovoltaic system and the power taken off by means of the consumer system.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2022 203 741A1

[0007]

Claims

Method (100) for determining a setpoint value of a charging power for charging a battery (32) of a vehicle (30) by means of a charging device (12), wherein the charging device (12) is electrically connectable, in particular connected, to a photovoltaic system (14) and a consumer system (20), having the following steps: - reading in (110), by means of a computing unit (28), a power information item which represents a difference between actual values of a power provided by the photovoltaic system (14) and a power drawn by means of the consumer system (20) and a charging power provided by means of the charging device (12) for charging the battery (32) of the vehicle (30); and - determining (130) the setpoint value of the charging power based on the read-in power information by means of the arithmetic unit (28), wherein the determined setpoint value of the charging power represents an excess in the provided power in order to charge the battery (32) of the vehicle (30) with the determined setpoint value of the charging power by means of the charging device (12), characterized in that - a reference power information item is read in by means of the arithmetic unit (28) as a function of, in particular in the case of, non-availability of, the power information item to be read in, and - the setpoint value of the charging power is determined based on the read-in reference power information item.Method (100) according to Claim 1, characterized in that the reference power information item represents a reference difference between a power provided by the photovoltaic system (14) and a power drawn by means of the consumer system (20) and a charging power provided by means of the charging device (12) for charging the battery (32) of the vehicle (30).Method (100) according to Claim 1 or 2, characterized in that the reference power information item is based on - a first reference value for the power provided by the photovoltaic system (14), - a second reference value for the power drawn by means of the consumer system (20), and - the actual value of the charging power provided by means of the charging device (12) for charging the battery (32) of the vehicle (30).Method (100) according to Claim 1 or 2, characterized in that the reference power information item is based on - a first reference value for the power provided by the photovoltaic system (14) and - a second reference value for a sum of the power drawn by means of the consumer system (20) and the charging power provided by means of the charging device (12) for charging the battery (32) of the vehicle (30).Method (100) according to one of the preceding claims, characterized in that the reference performance information depends on a time of day, in particular further on a day of the week and / or a month, and the reference performance information to be read in is selected taking into account a current time of day, in particular further on a current day of the week and / or a current month.Method (100) according to one of the preceding claims, characterized in that the read-in reference power information is based on - measurement values of the power provided by the photovoltaic system (14) and / or of the power drawn by means of the consumer system (20) and / or of the charging power provided by means of the charging device (12) for charging the battery (32) of the vehicle (30) and / or - a model of the photovoltaic system (14) and / or of the consumer system (20) and / or of the charging device (12).Method (100) according to one of the preceding claims, characterized in that the reference performance information stored in a storage unit assigned to the arithmetic unit (28) and / or the first and / or second reference value stored in a storage unit assigned to the arithmetic unit (28) is updated on the basis of the actual values when the performance information is available.Method (100) according to one of the preceding claims, characterized in that the setpoint value of the charging power is determined using a control algorithm, in particular comprising a controller with an integral component.Method (100) according to one of the preceding claims, characterized bya step of charging (140) the battery (32) of the vehicle (30) with the determined setpoint value of the charging power by means of the charging device (12), wherein - additional power is provided to the charging device (12) by means of a power supply unit if the determined setpoint value of the charging power is greater than a difference between the actual values of the power provided by the photovoltaic system (14) and the power drawn by means of the consumer system (20), or - additional power is provided to a power draw unit by means of the charging device (12) if the determined setpoint value of the charging power is less than the difference between the actual values of the power provided by the photovoltaic system (14) and the power drawn by means of the consumer system (20).Computing unit (28) for determining a setpoint value of a charging power for charging a battery (32) of a vehicle (30) by means of a charging device (12), wherein the charging device (12) is electrically connectable to a photovoltaic system (14) and a consumer system (20), and the computing unit (28) is configured to - read in a power information item which represents a difference between actual values of a power provided by the photovoltaic system (14) and a power drawn by means of the consumer system (20) and a charging power provided by means of the charging device (12) for charging the battery (32) of the vehicle (32), and - determine the setpoint value of the charging power on the basis of the power information item, wherein the determined setpoint value of the charging power represents an excess of the power provided, In order to charge the battery (32) of the vehicle (30) with the determined setpoint value of the charging power by means of the charging device (12), characterized in that the arithmetic unit (28) is configured to - read in a reference power information item, and - determine the setpoint value of the charging power item, based on the read-in reference power information item, in particular in the case of non-availability.Charging device (12) for charging a battery (32) of a vehicle, wherein the charging device (12) - is electrically connectable, in particular connected, to a photovoltaic system (14) and a consumer system (20), - comprises a computing unit (28) according to claim 10, and - is configured to charge the battery (32) of the vehicle (30) with the nominal value of the charging power determined by means of the computing unit (28).System for charging a battery (32) of a vehicle, wherein the system comprises a charging device (12), in particular connected, which can be electrically connected, in particular connected, to a photovoltaic system (14) and a consumer system (20), and a computing unit (28) according to Claim 10, wherein - the computing unit (28) is arranged away from the charging device (12) and - the charging device (12) is designed to charge the battery (32) of the vehicle (30) with the charging power determined by means of the computing unit (28).Computer program comprising instructions, - which, when executed on a computing unit, in particular according to claim 10, cause said computing unit to execute the method (100) according to one of claims 1 to 9, and / or - which cause the charging device (12) according to claim 11 and / or the system according to claim 12 to execute the method (100) according to one of claims 1 to 9.A machine readable storage medium having stored thereon a computer program according to claim 13.

Images