DE102022108574A1 - Charging an electric vehicle on a local power grid - Google Patents

Abstract

A method is used to charge an electric vehicle (BEV) on a local power grid (1), which has at least one renewable energy source (2) and at least one charging point (EVSE) for charging the electric vehicle (BEV), wherein in the method for a with Charging point coupled electric vehicle (BEV) whose charging requirement and its expected departure time are provided, a predicted temporal distribution of excess power from the local power grid for the expected parking period of the electric vehicle (BEV) is determined based on a predicted temporal distribution of an electrical power of the at least one renewable energy source (2). a charging plan is drawn up for the coupled electric vehicle (BEV) based on the predicted time distribution of the excess power in such a way that the electric vehicle (BEV) has a desired state of charge at the expected departure time and the excess power is used to charge the electric vehicle (BEV), and that Electric vehicle (BEV) is charged according to the charging plan. The invention can be used particularly advantageously for charging plug-in hybrid vehicles and fully electrically powered vehicles in private households.

Description

The invention relates to a method for charging an electric vehicle on a local power grid, which has at least one regenerative energy source and at least one charging point for charging the electric vehicle, wherein in the method a predicted temporal distribution of an electrical power of the at least one regenerative energy source is determined, for which A charging plan for the coupled electric vehicle is drawn up based on the predicted performance and the electric vehicle is charged according to the charging plan. The invention also relates to a local power grid, having at least one local consumer, at least one renewable energy source and at least one charging point for charging an electric vehicle, the local power grid being set up to carry out the method. The invention also relates to a residential building with such a local power grid. The invention can be used particularly advantageously for charging plug-in hybrid vehicles and fully electrically powered vehicles in private households.

Intelligent energy controls in intelligent houses (“smart homes”) with a connection to photovoltaic systems are offered on the market, which make it possible to charge an electric vehicle battery at a charging station in the house using excess charging (e.g. under the trade name AMTRONO from MENNEKES Elektrotechnik GmbH & Co. KG).

With such excess charging, in practice the electric vehicle has so far only been charged when the photovoltaic system produces excess energy, i.e. with excess energy that would otherwise be fed into the public power grid. This allows the owner to increase his own photovoltaic consumption. This approach is very popular with owners of electric vehicles when purchasing electricity from the public power grid costs more than the remuneration for the electricity fed into the public power grid by the photovoltaic system. To date, this requires a connection of the charging station to the local network and an energy measuring device installed in the local network, whereby this “local network” energy measuring device records the electrical power drawn from the local network from the public power supply network and the electrical power fed into the public power supply network from the local network in the event of a surplus measures. A charging process will only be carried out if this “local network” energy measuring device detects the presence of excess energy. The “local network” energy measuring device measures the same power as an “external”, “billing-relevant” energy measuring device installed by the electricity supplier, an energy retailer or a measuring point operator at the network connection point, whereby the measurement data from the “local network” energy measuring device is available to the user of the local electricity network and thus to the Charging station is available, but the measurement data from the external energy measuring device installed by the electricity supplier is usually not.

The disadvantage here is the cost and installation effort required to connect the local network energy measuring device, which causes considerable construction effort, especially with retrofit solutions. There is also a disadvantage in that a charging process is carried out based on the ad hoc control (surplus currently available/not available) and a user therefore has no certainty as to whether his electric vehicle will have the charge level or storage level necessary for his mobility needs at the desired departure time will have.

US 9,937,810 B2 discloses a power distribution system for a building with a direct current bus and connected to it: a network connection point to a public power grid, several local consumers, a plurality of power electricity storage devices with respective desired minimum and maximum values of their state of charge and a data processing device for selectively switching the power on and off -Power storage and for setting up a charging and discharging plan for the power storage in such a way that power storage with a state of charge greater than their respective maximum value is first discharged before power storage is discharged whose state of charge is below their respective maximum value. In addition, power storage devices will first be charged with a state of charge lower than their respective minimum value, before power storage devices whose state of charge is above their respective minimum value will be charged. The power distribution system can also have a regenerative energy source, in particular a photovoltaic system, connected to the direct current bus, wherein the charging and discharging plan can then be set up based on a predicted future direct current power of the regenerative energy source. Further, as a power storage device, a traction battery of a commercial vehicle such as a forklift or golf cart, etc. connected to the DC bus via a charging point can be used.

WO 2020/186363 A1 discloses an apparatus and method for managing the output power of a power converter that includes a current input power meter for measuring the power drawn from a power connection of a household with a public supply network, a prediction module for the increase in power consumption in the household and a controller for limiting a current level output by the power converter in order to prevent the electrical power consumed by the power input from exceeding a predefined limit , if a most likely jump in the power consumed occurs. A user interface is further provided that allows a user to make changes to the maximum power level to charge an electric vehicle, the controller making suggestions to the user to adjust the power drawn and letting the user confirm the changes to make the allocation according to reassign to the user's settings. The household can have a photovoltaic system. Because electricity production from solar panels fluctuates and may not be easily synchronized with a load's electricity consumption, it is considered necessary to store the solar energy for later use, such as in a battery or other storage system, when solar power cannot be generated. A further development relates to a power converter, such as a bidirectional battery charger for electric vehicles, that provides suggestions to a user to adapt a power level provided by a charger to one or more electric vehicles and/or other loads in order to avoid exceeding a rated budget of the electrical power connection , when the largest likely jump in consumption occurs. To this end, a time-based prediction of the energy consumption of the non-charging load, the largest likely jump, may be based on modeling and/or historical monitoring of the energy consumption of the non-charging load. The household may also receive energy from a local generation source and display it to a user for planning electricity usage, e.g., a solar, wind, micro-hydro, or internal combustion engine generation source. In particular, the power generated by a photovoltaic system can be predicted to a user based on a weather forecast.

It is the object of the present invention to at least partially overcome the disadvantages of the prior art and, in particular, to provide a particularly cost-effective option for charging an electric vehicle in excess of a local power grid, in particular the power grid of a private household, which has a renewable energy source.

This task is solved according to the features of the independent claims. Preferred embodiments can be found in particular in the dependent claims.

• - für ein mit dem Ladepunkt gekoppeltes Elektrofahrzeug dessen Ladebedarf und dessen voraussichtliche Abfahrtszeit vorgehalten wird,
• - eine prognostizierte zeitliche Verteilung einer Überschussleistung des lokalen Stromnetzes für die voraussichtliche Abstelldauer des Elektrofahrzeugs anhand einer Differenz zwischen einer prognostizierten zeitlichen Verteilung einer elektrischen Leistung der mindestens einen regenerativen Energiequelle bestimmt wird,
• - für das gekoppelte Elektrofahrzeug ein Ladeplan anhand der prognostizierten zeitlichen Verteilung der Überschussleistung dergestalt aufgestellt wird, dass das Elektrofahrzeug zur voraussichtlichen Abfahrtszeit einen gewünschten Ladezustand aufweist und die Überschussleistung zum Laden des Elektrofahrzeugs verwendet wird, und
• - das Elektrofahrzeug entsprechend dem Ladeplan aufgeladen wird.

The object is achieved by a method for charging an electric vehicle on a local power grid, which has at least one renewable power or energy source and at least one charging point for charging the electric vehicle, wherein in the method

• - for an electric vehicle coupled to the charging point, its charging requirement and its expected departure time are kept available,
• - a predicted time distribution of an excess power of the local power grid for the expected parking period of the electric vehicle is determined based on a difference between a predicted time distribution of an electrical power of the at least one renewable energy source,
• - a charging plan is drawn up for the coupled electric vehicle based on the predicted temporal distribution of the excess power in such a way that the electric vehicle has a desired state of charge at the expected departure time and the excess power is used to charge the electric vehicle, and
• - the electric vehicle is charged according to the charging plan.

This method has the advantage that it does not require a local network energy meter, which saves costs and effort through installation, maintenance and operation. Nevertheless, based on the forecast(s), the electric vehicle can most likely be charged in excess. The forecast(s) also advantageously make it possible to make the charging plan particularly flexible in terms of time, which, for example, enables particularly cost-effective charging.

The electric vehicle can be a plug-in hybrid vehicle (also referred to as a “PHEV”) or a fully electric vehicle (also referred to as a “BEV”). Charging the electric vehicle includes charging an electrical energy storage device, hereinafter referred to as a “battery” without limiting generality, in particular at least one drive battery of the electric vehicle. The electric vehicle is in particular a passenger car or a motorcycle.

The local power grid is, in particular, a power grid connected to a public power grid, with typically one of at the grid connection point between the public power grid and the local power grid The energy supplier, an energy retailer or a measuring point operator has an external, typically billing-relevant energy measuring device installed, via which an amount of electricity drawn from the public power supply network and an amount of electricity fed into the public power supply network are measured, for example for billing purposes. The local power grid includes in particular an alternating voltage network to which direct voltage devices such as a photovoltaic system, a vehicle battery, a stationary power storage device, etc. are or can be connected via appropriate uni- or bi-directional power converters.

It is a further development that the external energy measuring device is a smart meter that automatically measures power and transmits it to a recording point. If this is the case, in a further development these measurement data can be forwarded to the user of the local power grid via a smart meter gateway, e.g. via an EEBus protocol.

It is an embodiment that the local power grid is a power grid of a private household, e.g. a private residential building or an apartment.

The at least one renewable energy source can include or be, for example, at least one photovoltaic system, at least one wind turbine, at least one geothermal system, etc. An electrical power of the at least one regenerative energy source corresponds to the “regenerative” electrical power fed into the local power grid by the at least one regenerative energy source. The (DC) photovoltaic system can be connected to the rest of the local (AC) power grid via a unidirectional inverter.

The at least one charging point can include or be at least one charging station with one or more charging points, at least one wallbox, at least one inductive charging area, etc. The charging point can also be referred to as “EVSE”.

The fact that an electric vehicle is coupled to the charging point can in particular include that the electric vehicle or its battery(s) can be charged through the charging point, e.g. because a charging cable is connected or the electric vehicle is parked on an inductive charging surface. It is a further development that the electric vehicle and the charging point can communicate with each other unidirectionally or bidirectionally digitally via a communication channel, for example in accordance with ISO 15118 / IEC 61851. Power electronics for converting the AC voltage from the grid into the DC voltage of the battery of the electric vehicle, and if necessary vice versa , can be done inside or outside the electric vehicle. The regulation of the charging and, if necessary, discharging process can be carried out by charging controllers, to which specifications for charging control are sent via the digital communication channel.

The fact that the charging requirement and the expected departure time of an electric vehicle coupled to the charging point are stored includes, in particular, that the charging requirement and the expected departure time are stored in a retrievable manner.

For example, the charging requirement and its expected departure time can be stored in a data processing device, which is in particular also set up to create the charging plan. The data processing device can be a data processing device located locally in the household, for example a computer or an IT system. Alternatively, the data processing device can be an external entity such as a cloud computer or a network server.

It is a further development that the charging requirement is determined from a difference between a current state of charge (SoC) of the electric vehicle and a desired state of charge. The desired state of charge can, for example, be a fixed value (e.g. 80% SoC) or a state of charge or storage level that is tailored to the mobility needs of the user of the electric vehicle after departure. The charging requirement can be, for example, an amount of energy. The determination of the charging requirement is basically known and will therefore not be explained further.

The departure time can, for example, be specified by a user, estimated by specifying a destination and a destination time together with route planning, or can be estimated from history data.

In the present case, the excess power of the local power grid corresponds to a difference in the power fed into the local power grid by the at least one renewable energy source minus the power consumed by local consumers of the local power grid at the same time. The at least one electric vehicle is not considered a local consumer. If excess power is available, it is at least partially used to charge the electric vehicle and only a portion not used for charging, if still available, can be fed into the public power supply network. Local consumers can, for example Kitchen appliances, washing machines, lamps, other electrical appliances, etc.

In the simplest case, the charging plan is based only on the forecast or expected or probable excess power and not on an ad hoc measurement of the electricity flowing at the network connection point to the public power supply network. As a result, the electric vehicle may have to be charged from the public power supply network at some times when the forecast differs from reality, but this possible cost disadvantage is usually more than compensated for by the saving of a local network energy meter at the charging point.

The charging plan can, for example, include a determination of a time distribution of a charging power requested or provided to charge the electric vehicle during the parking period of the electric vehicle (“load profile”).

Using the excess power from the local power grid to charge the electric vehicle may include using all or part of the excess power to charge the electric vehicle.

In a further development, the fact that the electric vehicle is charged according to the charging plan can include the charging plan being communicated to the charging point and then the charging point controlling the charging process. Alternatively, this can be understood to mean that the charging plan is communicated to the electric vehicle and then the electric vehicle controls the charging process. Charging the electric vehicle according to the charging plan can therefore include enabling the electric vehicle and/or the charging point to control the charging process according to the charging plan.

It is an embodiment that the at least one renewable energy source comprises a photovoltaic system and the predicted temporal distribution of the electrical power of the photovoltaic system only based on system data (e.g. comprising performance, orientation, installation location, etc.) and sun position data (e.g. comprising solar radiation, in particular Radiation intensity) is predicted. Such a forecast is particularly easy to provide. The system data is created when planning or setting up the photovoltaic system, and the sun position data is easily available for the installation location of the photovoltaic system.

It is an embodiment that the at least one renewable energy source comprises a photovoltaic system and the predicted temporal distribution of the electrical power of the photovoltaic system is predicted based on system data and sun position data and additionally based on historical data and/or weather forecasts. In this way, a particularly accurate forecast can advantageously be made.

It is an embodiment that the at least one renewable energy source is a wind turbine, the predicted temporal distribution of the electrical power of the wind turbine is predicted based on a wind forecast and a model of the wind turbine.

It is an embodiment that the predicted temporal distribution of the excess power of the local power grid is determined based on historical data from a local or external energy measuring device installed at a grid connection point between the local power grid and a public supply grid, to which no electric vehicle has been charged. This is advantageous because it allows electrical power consumption in the local power grid to be taken into account in a particularly simple way without special measurements. Such historical data can be determined, for example, for periods in which no charging point was yet connected to the local power grid, for times when there was no connection between the charging point and the electric vehicle, for periods outside of charging processes, etc.

It is an embodiment that the predicted temporal distribution of the excess power is determined based on a difference between the predicted temporal distribution of the electrical power of the at least one renewable energy source and a predicted temporal distribution of an electrical power consumed by the local power grid. This has the advantage that excess performance can be forecast particularly precisely.

It is an embodiment that the electrical power consumed by the local power grid is predicted based on historical data or based on an estimated temporal distribution. This is advantageously particularly easy to implement. The estimated time distribution can, for example, include an estimate based on typical energy consumption of houses of similar size, design, and possibly also location and/or number of residents.

It is an embodiment that the predicted time distribution of the consumed electrical power corresponds to a predetermined peak value. This is advantageous in order to charge the electric vehicle particularly reliably, only in excess. The peak value can, for example, be one measured maximum of a consumed electrical power or another value that is in particular higher than an average value of a power, for example 90% of the peak value, 125% of the average value. The peak value can be assumed to be constant for the charging or shutdown period to be planned or can correspond to a temporal power distribution with individual peak values at respective points in time.

It is an embodiment that the charging plan is set up or designed in such a way that the electric vehicle is or should only be charged when the predicted excess power exceeds a minimum threshold value required or recommended for charging the electric vehicle. This advantageously takes into account that certain periods of time may not be available for charging the electric vehicle despite a nominal surplus. This in turn enables even more reliable charging. For example, a minimum threshold may be 2 kW.

It is an embodiment that the local power grid is a power grid without buffer storage and the charging plan is set up in such a way that the excess power is used directly to charge the electric vehicle. This achieves the advantage that the local power grid can be designed to be particularly simple and the method is therefore particularly suitable for private households. The fact that the local power grid does not have a buffer can in particular mean that there is no stationary power storage connected to it, which is intended (i.e. designed and connected) to temporarily store the amount of electricity generated by the renewable energy source for later use in the local power grid.

It is an embodiment that the local power grid has a stationary power storage device, which is intended to temporarily store the electrical energy or electricity generated by the renewable energy source for later use in the local power grid. This advantageously enables a particularly flexible, well-optimized charging plan to be drawn up. It is an embodiment that the charging plan is drawn up in such a way that the excess power is used directly to charge the electric vehicle and that if no excess power is available, the electric vehicle is charged from the stationary power storage. This means that the charging plan can advantageously be set up more flexibly in terms of time. The stationary power storage can be connected to the rest of the local power grid via a bidirectional power converter, for example.

It is a further development that the stationary power storage is only fed from the renewable energy source.

It is an embodiment that if the charging requirement is greater than or equal to the excess energy forecast up to the time of departure, the electric vehicle is charged with maximum power from the forecast excess power. This has the advantage that a particularly large amount of excess energy can be used for charging or a particularly high proportion of the charging requirement is covered by excess energy. If desired or required, any remaining portion of the charging requirement can be supplied from the stationary power storage system, if available, and/or from the public power supply network.

• - besonders batterieschonendes Laden, insbesondere mit geringen Ladeströmen;
• - Stoppen des Ladens zu Zeiten, in denen es monetär sinnvoller ist, den Überschuss in das öffentliche Stromversorgungsnetz einzuspeisen als zum Laden eines Elektrofahrzeugs zu verwenden;
• - die Möglichkeit, die Batterie(n) des Elektrofahrzeugs als (ggf. zusätzlichen) Zwischenspeicher mit der Möglichkeit zur Rückspeisung in das lokale Stromnetz und/oder in das öffentliche Stromversorgungsnetz zu verwenden, falls eine solche Rückspeisefähigkeit, z. B. V2G, besteht.

It is an embodiment that if the charging requirement is lower than the excess energy predicted up to the time of departure, the electric vehicle is charged with less than the maximum power from the predicted excess power. As a result, the loading wheel conditions can advantageously be selected so that other advantages can be achieved in addition to reaching the desired charging state at the time of departure. The charging plan can be drawn up in such a way that it also achieves the following goals:

• - particularly battery-friendly charging, especially with low charging currents;
• - Stopping charging at times when it makes more monetary sense to feed the surplus into the public power grid than to use it to charge an electric vehicle;
• - the possibility of using the battery(s) of the electric vehicle as (possibly additional) intermediate storage with the possibility of feeding back into the local power grid and/or into the public power grid, if such recovery capability, e.g. B. V2G.

As already stated above, the method can advantageously also be carried out at the charging point without a local network energy measuring device. However, it is an advantageous further development that additional measurement data about an energy or power flow from the local power grid to the public power grid and vice versa is available, be it through the presence of a local grid energy measuring device or through an external “smart meter” house meter from the energy supplier/ Measuring point operator at the grid connection point, whose measurement data is available to the user of the local power grid. In particular, this can prevent charging periods during which the electric vehicle would be charged from the public power supply network. In addition, the advantages of the forecast for the future charging plan remain, and the forecast quality can even be improved by the measurement data.

The forecast quality can also be improved by using certain additional measured values to check and/or update the charging plan during the charging process, for example in order to improve its target accuracy and/or to improve its forecast quality.

• - Messwerte der aus der Photovoltaik-Anlage in das lokale Stromnetz eingespeisten PV-Leistung, gemessen z.B. durch den zugehörigen Wechselrichter;
• - Messwerte der mit dem Zwischenspeicher ausgetauschten Energiemenge, gemessen z.B. durch den zugehörigen Stromrichter;
• - Messwerte der mit dem Ladepunkt ausgetauschten Energiemenge bzw. der tatsächlichen Lade- bzw. Rückspeise-Energiemenge zu bzw. von dem Elektrofahrzeug, gemessen beispielsweise durch einen dem Ladepunkt zugeordneten Gleichrichters oder Stromrichters.

For example, the following additional measured values can be used to set up and/or update the charging plan:

• - Measured values of the PV power fed into the local power grid from the photovoltaic system, measured for example by the associated inverter;
• - Measured values of the amount of energy exchanged with the buffer, measured for example by the associated power converter;
• - Measured values of the amount of energy exchanged with the charging point or the actual amount of charging or recovery energy to or from the electric vehicle, measured for example by a rectifier or power converter assigned to the charging point.

It is a further development that the performance forecast(s) that are still available from the time of measurement are themselves updated based on the measured amounts of energy or performance.

If no departure time is specified and there is no other departure time, the electric vehicle can, for example, be charged to a desired charge level as quickly or as battery-friendly as possible. If the desired charge level is not known, you can, for example, charge to a standard charge level, e.g. 80% SoC. If the electric vehicle is capable of regenerative energy, it can then also be used as a buffer storage, with any deviation from the desired state of charge then being kept within a rather narrow band of the state of charge (e.g. of +/- 10% SoC).

The task is also solved by a local power grid, having at least one local consumer, at least one renewable power or energy source and at least one charging point for charging an electric vehicle, the local power grid being set up to carry out the method as described above.

It is a further development that the local power grid has a data processing device (also referred to as an “IT system”), which can be connected to the electric vehicle and/or to the charging point for data technology and is set up to at least partially implement the method according to one of the preceding claims carry out, in particular drawing up the loading plan. Alternatively or additionally, the local power network can be connected or connected in terms of data technology to such an external data processing device such as a network server or a cloud computer, for example via a network such as the Internet or similar. The connection to the external data processing device enables the local power network to carry out the method as described above . In another perspective, the method as described above is then solved by a system consisting of the local power grid and the external data processing device connected to it.

• - Der Ladepunkt ist über das OCPP Protokoll an die Datenverarbeitungseinrichtung bzw. das IT-System angebunden;
• - Das Elektrofahrzeug und/oder ein Nutzerendgerät, insbesondere mobiles Nutzerendgerät, z.B. ein Smartphone, sind mit der Datenverarbeitungseinrichtung vernetzt. Informationen bzw. Präferenzen zum Fahrzeugzustand und Ladevorgang werden im Elektrofahrzeug und/oder das Nutzerendgerät dargestellt und gesteuert;
• - Das Elektrofahrzeug und/oder das Nutzerendgerät kommuniziert beispielsweise eine ID, Ankunftszeit, gewünschte oder abgeschätzte Abfahrtzeit und benötigte und verfügbare Energiemengen der Fahrzeugbatterie an die Datenverarbeitungseinrichtung;
• - Die Datenverarbeitungseinrichtung ist dazu eingerichtet, z.B. dazu programmiert, eine Prognose der Energieerzeugung durch die regenerative Energiequelle(n), eine Prognose des Energieverbrauchs und ggf. eine Energiespeicherprognose vorzuhalten oder zu berechnen. Beispielsweise kann die Energieerzeugungsprognose mit Aufstellung der regenerativen Energiequelle in der Datenverarbeitungseinrichtung hinterlegt worden sein, z.B. in Form einer Tabelle oder Kennlinie;
• - Die Prognose der Energieerzeugung wird insbesondere abgeglichen mit dem erwarteten Energieverbrauch im lokalen Stromnetz und ggf. der Energiespeichermöglichkeiten entweder durch einen stationären Stromspeicher oder unter Einbeziehung der Fahrzeugbatterie als zusätzlichen Pufferspeicher im Fall eines rückspeisefähigen Elektrofahrzeugs;
• - Eine lokale Energiemessung kann zusätzlich oder alternativ durch den „Smart Meter“-Hauszähler des Energieversorgers/Messtellenbetreibers am Netzanschlusspunkt erfolgen und in die Energieerzeugung/ -verbrauchs-Prognose mit eingehen.
• - Ein Optimierer bzw. eine mit einem Optimierungsalgorithmus programmierte Datenverarbeitungseinrichtung nutzt die Ankunftszeit, Abfahrtzeit sowie die benötigten und verfügbaren Energiemengen und prognostiziert einen Lastgang (Leistung (P) über die Zeit (t)), der für den Ladepunkt / das Elektrofahrzeug auf einen Ladezustand des Elektrofahrzeugs zum Zeitpunkt der Abfahrtzeit hin optimiert ist;
• - Das Laden des Elektrofahrzeugs erfolgt unter Nutzung regenerativer Energie aus Eigenerzeugung und insbesondere unter einer Minimierung des Netzbezugs, wobei auch Speicherkapazitäten durch stationäre Energiespeicher und Elektrofahrzeuge mit Rückspeisefähigkeit prognostiziert werden können;
• - Wenn ein Netzbezug notwendig ist, sollte dieser zu möglichst geringen Kosten und/oder mit Strom aus erneuerbaren Energien sattfinden;
• - Wenn Energie in das öffentliche Stromversorgungsnetz eingespeist wird, passiert dies vorteilhafterweise zu Zeiten, zu denen maximale Erlöse erwirtschaftet werden können bzw. der Bedarf an erneuerbaren Energien hoch ist. So wird sichergestellt, dass das Elektrofahrzeug zur Abfahrtzeit auf den z.B. durch den Nutzer spezifizierten Ladezustand bzw. Speicherfüllstand geladen ist, und zwar unter Optimierung des Energieeigenbedarfs, der Energiekosten, der Energieerlöse und/oder der Nutzung von CO₂freien erneuerbaren Energien;
• - Der Nutzer kann, z.B. über das Nutzerendgerät, informiert werden, wenn diese Optimierung nicht erreicht werden kann.

The local power grid can in particular have one or more of the following components and/or properties:

• - The charging point is connected to the data processing device or IT system via the OCPP protocol;
• - The electric vehicle and/or a user terminal, in particular a mobile user terminal, for example a smartphone, are networked with the data processing device. Information or preferences regarding the vehicle status and charging process are displayed and controlled in the electric vehicle and/or the user terminal;
• - The electric vehicle and/or the user terminal communicates, for example, an ID, arrival time, desired or estimated departure time and required and available amounts of energy from the vehicle battery to the data processing device;
• - The data processing device is set up, for example programmed, to maintain or calculate a forecast of energy production by the renewable energy source(s), a forecast of energy consumption and, if necessary, an energy storage forecast. For example, the energy production forecast with a list of the renewable energy source can have been stored in the data processing device, for example in the form of a table or characteristic curve;
• - The forecast of energy production is compared in particular with the expected energy consumption in the local power grid and, if necessary, the energy storage options either through a stationary power storage system or including the vehicle battery as an additional buffer storage in the case of a regenerative electric vehicle;
• - Local energy measurement can additionally or alternatively be carried out by the energy supplier/measuring point operator's “smart meter” house meter at the grid connection point and included in the energy production/consumption forecast.
• - An optimizer or a data processing device programmed with an optimization algorithm uses the arrival time, departure time as well as the required and available amounts of energy and predicts a load profile (power (P) over time (t)) that corresponds to a charging state of the charging point / electric vehicle Electric vehicle is optimized at the time of departure;
• - The electric vehicle is charged using renewable energy from self-generation and in particular by minimizing the grid consumption, whereby storage capacities can also be predicted through stationary energy storage and electric vehicles with regenerative capacity;
• - If a connection to the grid is necessary, it should be at the lowest possible cost and/or with electricity from renewable energies;
• - When energy is fed into the public power supply network, this advantageously happens at times when maximum revenue can be generated or when the need for renewable energies is high. This ensures that the electric vehicle is charged at the time of departure to the charge level or storage level specified by the user, for example, while optimizing its own energy requirements, energy costs, energy revenues and/or the use of CO2 _- free renewable energies;
• - The user can be informed, for example via the user device, if this optimization cannot be achieved.

The task is further solved by a residential building, in particular a private residential building, having a local power grid as described above. The residential building can be designed analogously to the method and/or to the local power grid, and vice versa, and has the same advantages.

The characteristics, features and advantages of this invention described above and the manner in which they are achieved will be more clearly and clearly understood in connection with the following schematic description of an exemplary embodiment, which will be explained in more detail in connection with the drawings.

1 shows a sketch of a local power grid 1 to which a BEV electric vehicle is connected. The local power grid 1 is part of a private house PH, which is equipped with a photovoltaic system 2, in particular a roof system, which is connected to the rest of the local power grid 1 via an inverter 2a. The local power network 1 is an alternating current network that can, for example, have a nominal voltage of 110 V, 230 V or - in the case of three-phase current for 3-phase charging - between 380 V and 400 V. Consumers such as kitchen appliances 3, lamps, multimedia devices, air conditioning, etc. are connected to the local power grid 1. Optionally, a stationary power storage 4 can be connected to the local power grid 1 via a bidirectional power converter 4a. Furthermore, a charging point in the form of a wallbox EVSE is connected to the local power grid 1, via which a battery 5 of the electric vehicle BEV can be charged and optionally discharged again. The wallbox EVSE and the electric vehicle BEV can communicate bidirectionally when coupled, for example in accordance with ISO 15118 / IEC 61851.

The local power grid 1 is also connected to a public power grid 7 via an “external” energy measuring device installed by a measuring point operator, here optionally designed as a smart meter 6.

The smart meter 6 as well as the wallbox EVSE and/or the electric vehicle BEV can be linked in terms of data technology to an external IT system 8 (as indicated by the lightning-like arrows), e.g. wired and/or wirelessly via a communication network such as the Internet, etc. The IT -System 8 can be implemented, for example, on a network server or as a cloud computer.

The situation is further described below in which a user has coupled his electric vehicle BEV with the Wallbox EVSE, for example by connecting it to the Wallbox EVSE via a charging cable. The user can now enter a desired departure time or activate or change a suggested or stored departure time via a user terminal, for example his smartphone 9, on which a corresponding application program is running. The expected departure time is transmitted to the IT system 8.

Alternatively, the departure time can be transmitted from or via the BEV electric vehicle to the IT system 8 directly or via the EVSE wallbox. The electric vehicle BEV can also, for example, have an ID, the arrival time and required and available amounts of energy, in particular a charging requirement at the time of departure is transmitted to the IT system 8 directly or via the EVSE wallbox.

In the IT system 8, a predicted time distribution of an electrical power or energy produced by the photovoltaic system 2 and a predicted time distribution of the energy or power consumption of the consumers 3 are stored, in particular stored in a retrievable manner. From this, the IT system 8 can predict a temporal distribution of excess power from the local power grid 1 for the expected parking period of the electric vehicle BEV up to its departure time. If a stationary power storage 4 is present, the temporal distribution of the excess power can also include a forecast of a charge and discharge of the stationary power storage 4, which can use, for example, a storage capacity, a state of charge, etc. of the stationary power storage 4.

From this, the IT system 8 can draw up a charging plan for the coupled electric vehicle BEV in such a way that the electric vehicle BEV has the desired state of charge at the expected departure time and the highest possible excess power is used to charge the electric vehicle if this is cheaper than charging from the public power supply network 7. The charging plan can, for example, be based on a high proportion of electricity from renewable energies with a view to keeping costs as low as possible. To do this, the IT system 8 can access information about prices for grid purchases, revenues for grid feed-in, etc., at least for the parking period of the BEV electric vehicle.

The charging plan can be transferred to the BEV electric vehicle or the EVSE wallbox, which then charges the BEV electric vehicle according to the charging plan.

Optionally, the electric vehicle BEV can also have the ability to regenerate electricity and thus also serve as a buffer for the local power grid 1.

The above method is particularly suitable for being able to dispense with a local network energy measuring device 10, which is usually required for ad hoc excess charging. If the external energy measuring device is designed as a smart meter 6 as shown here and is set up to transmit measurement data to the user of the local power network 1, ad hoc excess charging can also be carried out without a local network energy measuring device 10, in particular preventing the electric vehicle BEV is charged from the public power grid. However, the advantage of drawing up a charging plan based on the forecast(s) still remains.

Optionally, the forecast excess power can be updated based on energy flows measured in the local power grid 1 in order to improve forecast accuracy. In a further development, the forecast about the electrical energy expected to be fed in by the photovoltaic system 2 can be compared by a PV energy measuring device 11 present between the photovoltaic system 2 and the rest of the local power grid 1. The PV energy measuring device 11 can be integrated into the inverter 2a in a further development, so that z. B. the current performance of the photovoltaic system 2 can be measured via the inverter 2a.

In addition, in a further development, the forecast about the excess power can be compared by a buffer energy measuring device 12 present between the buffer 4 and the rest of the local power grid 1. In a further development, the buffer energy measuring device 12 can be integrated into the bidirectional power converter 4a, so that, for example, the power currently received or delivered by the buffer 4 can be measured via the power converter 4a.

In addition, the charging or discharging power of the electric vehicle BEV itself can be measured by an EVSE energy measuring device 13. The EVSE energy measuring device 13 can be integrated into the EVSE wallbox in a further development

In a further development, a local network energy measuring device 10 can also be present, which can, for example, take over the function of the external energy measuring device if it is not designed as a smart meter 6 or does not transmit measurement data to the user of the local power network 1.

In particular, the above energy measuring devices 10 to 13, if present, can report their measurement data regarding the electrical power or amounts of energy passed through them to the IT system 8, which can then be set up to record deviations of the forecast(s) from the actually occurring power recognize. This can in turn be used by the IT system 8 to update the charging plan and/or to adjust at least one of the forecasts for generation and consumption in the local power grid 1.

Of course, the present invention is not limited to the exemplary embodiment shown.

In general, “a”, “an” etc. can be understood as a singular or a plural, in particular in the sense of “at least one” or “one or more” etc., as long as this is not explicitly excluded, for example by the expression “exactly on” etc.

A numerical statement can also include exactly the number specified as well as a usual tolerance range, as long as this is not explicitly excluded.

Reference symbol list

1

Local power grid

2

Photovoltaic system

2a

Inverter

3

kitchen appliance

4

Stationary electricity storage

4a

Power converter

5

battery

6

Smart meters

7

Public power supply network

8th

IT system

9

Smartphone

10

Local network energy meter

11

PV energy meter

12

Temporary storage energy meter

13

EVSE energy meter

BEV

Electric vehicle

EVSE

Wallbox

Ph

Private house

QUOTES INCLUDED IN THE DESCRIPTION

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

Cited patent literature

• US 9937810 B2 [0005]
• WO 2020186363 A1 [0006]

Claims (15)

Method for charging an electric vehicle (BEV) on a local power grid (1), which has at least one renewable energy source (2) and at least one charging point (EVSE) for charging the electric vehicle (BEV), wherein in the method - for an electric vehicle (BEV) coupled to the charging point, its charging requirement and its expected departure time are kept available, - a predicted time distribution of an excess power of the local power grid for the expected parking period of the electric vehicle (BEV) is determined based on a predicted time distribution of an electrical power of the at least one renewable energy source (2), - a charging plan is drawn up for the coupled electric vehicle (BEV) based on the predicted time distribution of the excess power in such a way that the electric vehicle (BEV) has a desired state of charge at the expected departure time and the excess power is used to charge the electric vehicle (BEV), and - the electric vehicle (BEV) is charged according to the charging plan. Procedure according to Claim 1 , in which the at least one renewable energy source comprises a photovoltaic system (2) and the predicted temporal distribution of the electrical power of the photovoltaic system (2) is predicted only based on system data and sun position data. Procedure according to Claim 1 , in which the at least one renewable energy source comprises a photovoltaic system (2) and the predicted temporal distribution of the electrical power of the photovoltaic system (2) is predicted based on system data and sun position data and additionally based on historical data and / or weather forecasts. Procedure according to Claim 1 , in which the predicted temporal distribution of the excess power of the local power grid (1) is determined based on historical data from an electricity measuring device (8) installed at a grid connection point of the local power grid (1) to a public power grid (7), which does not include an electric vehicle (BEV) has been loaded. Method according to one of the preceding claims, in which the predicted temporal distribution of the excess power is determined based on a difference between the predicted temporal distribution of the electrical power of the at least one renewable energy source (2) and a predicted temporal distribution of an electrical power consumed by the local power grid. Method according to one of the preceding claims, in which the electrical power consumed by the local power grid (1) is predicted based on history data or an estimated temporal distribution. Procedure according to Claim 6 , whereby the predicted temporal distribution of the consumed electrical power corresponds to a particularly constant peak value. Method according to one of the preceding claims, in which the charging plan is drawn up in such a way that the electric vehicle (BEV) should only be charged when the predicted excess power exceeds a minimum threshold value required or recommended for charging the electric vehicle (BEV). Method according to one of the preceding claims, in which the local power grid (1) is a power grid without buffer storage and the charging plan is set up in such a way that the excess power is used directly to charge the electric vehicle (BEV). Method according to one of the preceding claims, in which the local power grid (1) has a stationary power storage (4) which is intended to temporarily store the electrical power generated by the renewable energy source (2) for later use in the local power grid (1). and the charging plan is drawn up in such a way that the excess power is used directly to charge the electric vehicle (BEV) and that when no excess power is available, the electric vehicle (BEV) is charged from the stationary power storage (4). Method according to one of the preceding claims, in which if the charging requirement is greater than or equal to the excess energy forecast up to the departure time, the electric vehicle (BEV) is charged with maximum power from the forecast excess power. Method according to one of the preceding claims, in which if the charging requirement is lower than the excess energy predicted up to the time of departure, the electric vehicle (BEV) is charged with less than maximum power from the predicted excess power. Method according to one of the preceding claims, in which the charging point is a private charging point, in particular a wallbox (EVSE). Local power grid, comprising at least one local consumer (3), at least one renewable energy source (2) and at least one charging point (EVSE) for charging an electric vehicle (BEV), the local power grid (1) being set up to carry out the method according to one of to carry out the preceding claims. Residential building (PH), having a local power network (1). Claim 14 .

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