METHOD AND CENTRAL CONTROL SYSTEM FOR CONTROLLING THE ELECTRIC CHARGING OF A GROUP OF VEHICLES

Description

[0001] The invention relates to a method for controlling the electrical charging of a group of vehicles and a corresponding control system.

[0002] It is known from the state of the art (program "BMW i ChargeForward", see e.g. https: / / www.engadget.com / 2015 / 07 / 31 / bmw-pge-chargeforward / ?ncid=rss_truncated) to control the charging of the energy storage systems of a group or pool of electric vehicles via a control system in such a way that the requirements of the operator of the electricity grid used for charging are also taken into account with regard to power reduction. In other words, if the electricity grid operator requests it, the charging of certain vehicles in the vehicle pool can be interrupted or delayed in order to reduce power consumption in the electricity grid. Charging is only suspended for those vehicles for which the interruption of the charging process does not affect a departure time specified by the vehicle user; that is, even if the charging process is resumed later, there is still sufficient time available to fully charge the vehicle.to charge up to a predetermined charge level.

[0003] In the above procedure, where the charging of a vehicle pool is influenced to compensate for overloads in the power grid, it may happen that a power reduction desired by the power grid operator cannot be achieved by interrupting the charging processes of the vehicle-side energy storage systems, since charging can only be suspended for a few vehicles in order to comply with departure times.

[0004] German patent application DE 10 2011 008 675 A1 discloses a method for charging the batteries of vehicles in a fleet according to the preamble of claim 1, wherein the vehicles use charging profiles with the lowest possible costs.

[0005] Document US 2015 / 0298567 A1 discloses a method for controlling the electric charging of electric vehicles. In this method, a command to reduce electrical energy consumption is transmitted from an energy supplier to a server, which then interrupts the charging of certain electric vehicles by means of an interrupt command.

[0006] Document US 2016 / 009192 A1 describes a method for optimizing the use of electrical energy from an electrical grid. This involves charging electrical devices, such as plug-in electric vehicles, with a charging profile based on a cost function for the electrical grid.

[0007] German patent application DE 10 2011 003 993 A1 discloses a charge controller for charging the battery of a plug-in hybrid vehicle, wherein the charge controller determines a charging schedule that includes a first charging time to charge the battery using a solar photovoltaic generation system and a second charging time to replenish the battery's electrical energy deficit using another electrical energy source. This patent application also discloses, among other things, the ability to advance the battery charging process if the charge controller detects an earlier departure time than usual.

[0008] The object of the invention is therefore to control the process of charging a group of vehicles in such a way that, at the request of a power grid operator, the charging process of a large number of vehicles can be interrupted.

[0009] This task is solved by the independent patent claims. Further developments of the invention are defined in the dependent claims.

[0010] The method according to the invention serves to control the electric charging of a group of vehicles that are electrically connected to a power grid of an electricity grid operator, wherein the respective vehicles draw electricity from the grid to charge an on-board electrical energy storage device for powering the respective vehicle. In other words, the vehicles are electrically powered vehicles, such as pure electric vehicles or hybrid vehicles. In the method according to the invention, a central control system can communicate with the respective vehicles of the group as well as with a server of the electricity grid operator. A central control system is understood to be a control system or control device that controls the charging of all vehicles in the group. This control system is implemented, in particular, via software on a corresponding server.The central control system can suspend the charging of at least some of the vehicle's energy storage in response to a received reduction command from the grid operator's server, which specifies a power amount by which the power consumption of the group of vehicles from the grid is to be reduced.

[0011] In the method according to the invention, a charging time window, a departure time, and a target state of charge (preferably a fully charged state) of the vehicle's energy storage system at the departure time are predefined for one or more specific vehicles of the group. During the charging process of the vehicle's energy storage system according to the charging time window, a charging time criterion is met, such that (i.e., if the charging time criterion is met) the charging process lies entirely within the charging time window or encompasses the entire charging time window, and it is simultaneously ensured that the target state of charge is reached no later than the departure time. Furthermore, a cost value for the charging time window is specified according to a cost function, which indicates a cost level depending on the charging process within the charging time window.The cost function can be chosen differently; preferably, it reflects the monetary electricity costs for the corresponding charging process, as will be mentioned again below.

[0012] The aforementioned predefined parameters are known to the central control system; that is, they are stored in a corresponding memory within the control system. The charging window, departure time, and target state of charge for each specific vehicle are predefined user-specific data entered by the user of that specific vehicle on an end device, particularly a mobile device (e.g., a mobile phone), and transmitted from the end device to the central control system. According to the definition above, a specific vehicle is defined as one from the group of vehicles for which the charging window, departure time, and target state of charge are predefined.

[0013] In the method according to the invention, the central control system transmits a modified charging time window to at least some of the specific vehicles. The charging process is then carried out according to the modified charging time window, fulfilling the charging time criterion while maintaining the same departure time and target state of charge. This means that the predetermined departure time and target state of charge remain unchanged, and the charging time criterion is now considered based on the modified charging time window, as defined above. The modified charging time window is characterized by the fact that it includes at least one time period that precedes the start of the unmodified (i.e., predetermined) charging time window. Furthermore, the cost value according to the cost function for the modified charging time window is equal to or less than the cost value for the unmodified charging time window.For specific vehicles where the charging time windows are not modified, the charging process is carried out according to the unmodified charging time window. The charging process for each vehicle is preferably controlled solely by the vehicle itself, but may also involve the central control system.

[0014] The method according to the invention achieves the suitable advancement of predetermined charging time windows for vehicles within a vehicle group, without affecting the costs of the charging process or the departure time. In this way, on average, more vehicles are available in the event of a reduction order from the electricity grid operator.

[0015] The costs according to the cost function can be defined differently depending on the application. Preferably, the cost function depends on the monetary electricity costs for a charging process within the charging time window and / or on the amount of exhaust gases generated by the electricity grid during the charging process within the charging time window and / or on the proportion of renewable energy used by the electricity grid during the charging process within the charging time window. The cost level according to the cost function is higher the greater the monetary electricity costs and / or the amount of exhaust gases and / or the lower the proportion of renewable energy. The amount of exhaust gases preferably refers to the amount of CO₂ produced, but can optionally also refer to other exhaust gases, such as nitrogen oxides, or take these other exhaust gases into account.

[0016] In a particularly preferred embodiment of the method according to the invention, if the central control system suspends the charging of the vehicle's energy storage system in response to a reduction command, a new charging time window, which differs from the currently used charging time window, is transmitted from the central control system to the specific vehicle. The start of the charging time window is after a predetermined period of charging suspension, and otherwise the charging process according to the new charging time window fulfills the above charging time criterion with an unchanged departure time and target state of charge. This ensures that a predetermined target state of charge is reached at a corresponding departure time, even if the charging process is interrupted for the vehicle's energy storage system in question.

[0017] In a preferred embodiment of the above-described design, the new charging time window includes a buffer that accounts for a reduced charging efficiency compared to the expected charging efficiency of the vehicle's energy storage system. This prevents the vehicle's energy storage system from starting to charge before the new or predetermined charging time window begins. This avoids the potential overlap of the new charging time window with the period during which charging of the energy storage system is suspended.

[0018] In another preferred embodiment of the method according to the invention, all modified loading time windows are reset to the predefined loading time windows after a predetermined number of reduction commands have been processed by the central control system.

[0019] In a further, particularly preferred embodiment of the method according to the invention, a stationary energy storage system is connected to the power grid.This stationary energy storage system is preferably a stationary battery storage system and is controlled by the central control system in such a way that, if the reduction in the power consumption of the group of vehicles by the power amount according to a reduction command cannot be achieved exclusively by suspending the charging of the energy storage systems of the respective vehicles, the power consumption of the stationary energy storage system from the power grid is reduced or the power output of the stationary energy storage system into the power grid is increased, so that the reduction in the power consumption of the group of vehicles, which is achieved by suspending the charging of the energy storage systems of the respective vehicles, plus the amount of the reduction in power consumption or the increase in power output of the stationary energy storage system corresponds to the power amount according to the reduction command.This variant of the invention compensates for an insufficient reduction in the performance of vehicle-side energy storage systems via a stationary energy storage system.

[0020] In addition to the method described above, the invention relates to a central control system for managing the electric charging of a group of vehicles electrically connected to a power grid of a grid operator, wherein the respective vehicles draw power to charge an on-board energy storage device for propulsion of the respective vehicle, and wherein the central control system can communicate with the respective vehicles as well as with a server of the grid operator. The central control system can suspend the charging of at least some of the on-board energy storage devices in response to a received reduction command originating from the grid operator's server, which specifies a power amount by which the power consumption of the group of vehicles from the grid is to be reduced.

[0021] The central control system is designed such that, for one or more specific vehicles in the group, a charging time window, a departure time, and a target state of charge of the vehicle's energy storage system at the time of departure are predefined. During the charging process of the vehicle's energy storage system, a charging time criterion is met according to the charging time window, ensuring that the charging process falls entirely within the charging time window or encompasses the entire charging time window, while simultaneously ensuring that the target state of charge is reached no later than the time of departure. A cost value for the charging time window is specified according to a cost function, which indicates a cost level depending on the charging process within the charging time window.

[0022] The central control system is further designed in such a way that it transmits a modified charging time window to a respective specific vehicle or at least some of the specific vehicles, whereupon the charging process is carried out according to the modified charging time window while fulfilling the charging time criterion with an unchanged departure time and target state of charge, wherein the modified charging time window includes at least a time period that lies before the start of the non-modified charging time window and wherein the cost value according to the cost function for the modified charging time window is equal to or less than the cost value for the non-modified charging time window.

[0023] The control system described above is preferably designed in such a way that it can execute one or more preferred variants of the method according to the invention.

[0024] Exemplary embodiments of the invention are described in detail below with reference to the accompanying figures.

[0025] They show: Fig. 1 a schematic representation of an infrastructure in which an embodiment of the method according to the invention is carried out; Fig. 2 a flowchart illustrating the process of an embodiment of the method according to the invention; and Figs. 3 to 6 diagrams showing different variants of adjusting loading time windows.

[0026] In Fig. 1A schematic representation of an infrastructure for carrying out the method according to the invention is shown. A key component of this infrastructure is a central control unit CO, which is integrated into a server SE and serves to control the charging of a fleet of several electrically powered vehicles (i.e., the drive batteries of these vehicles). Three electric vehicles 1 from this fleet are shown as examples. These vehicles are connected to the control unit CO via a portal PT. The control system CO has access to the portal PT via a suitable control backend (not shown), which in turn can communicate with the individual vehicles 1, e.g., via SMS. Using the communication channel via the portal PT, a charging time window can be transmitted from the control system CO to the individual vehicles 1, as described below.

[0027] Each vehicle (1) in the fleet has a user with a smartphone (2), although for clarity only one smartphone is shown. This smartphone allows the user to communicate with the CO control system via the (not shown) control backend and with their vehicle via the PT portal. Specifically, when charging the vehicle's traction battery via the power grid, the user can specify a charging window during which charging is particularly cost-effective. The battery will then be charged preferentially within this window. The user can also set a departure time and the target charge level at that time (usually 100%). This data is transmitted via the smartphone (2) to both the central CO control system and the user's vehicle (1).

[0028] The CO control system communicates according to Fig. 1also with a server SE, which belongs to a power grid operator, on whose power grid the vehicles 1 of the vehicle fleet or their batteries are charged. In addition, the infrastructure of Fig. 1 An energy storage system in the form of a stationary battery storage unit (SB) is provided, which can be controlled via the CO control system using a suitable interface and belongs to the operator of the CO control system. The operator of the control system is, for example, the manufacturer of vehicles 1 in the vehicle fleet.

[0029] One goal of the infrastructure of Fig. 1The system consists of the grid operator being able to send commands via its server SE to the control system CO in the event of an overload in its grid. The control system then suspends the charging of at least some of the currently charging vehicles 1 for a predetermined interruption period, thereby reducing the load on the grid. In the embodiment described here, the interruption period is fixed at one hour. Only the charging process of those vehicles is suspended for which it is ensured that, after resuming charging after the interruption period, there is still sufficient time before departure to charge the respective vehicle's traction battery to its target state of charge.To ensure that it is possible to suspend the charging process in as many vehicles as possible, the procedure described here involves bringing forward a charging time window specified in advance by the user of the respective vehicle for at least some of the vehicles, without increasing the corresponding charging costs.

[0030] Fig. 2 A flowchart illustrates the steps involved in shifting the charging time, using a single vehicle from the fleet as an example. According to step S1 of the Fig. 2 The user connects their vehicle to the electricity grid of the grid operator via a suitable charging station, which also hosts the server SE' of the Fig. 1The user operates the system. Using a suitable app on their smartphone, the user specifies a charging time window (LF) during which the vehicle should be charged, as electricity is particularly inexpensive during this period. They also set a future departure time (AZ) and a target charge level (SL) that the drive battery should have reached at the time of departure. If necessary, the target charge level can be preset for the user, eliminating the need to specify it again via the app.

[0031] In step S2, the charging time window LF, the departure time AZ and the target charge state SL are determined via the infrastructure of the Fig. 1The information is transmitted to the central control system CO. Conventionally, the charging of the user's vehicle takes place within the predefined charging time window LF, such that the charging process of the traction battery falls entirely within the charging time window or encompasses the entire charging time window, while simultaneously ensuring that the target charge level SL is reached no later than the vehicle's departure time AZ. According to the invention, the charging time window LF is now modified by the control system CO, as described in step S3 of the... Fig. 2 is reproduced.

[0032] According to step S3, when modifying the charging time window LF, a cost value KW is taken into account, which specifies the costs of charging using the charging time window LF. In the embodiment described here, these costs are the electricity costs for the corresponding charging process according to the charging time window LF. Alternatively or additionally, the costs can also take into account other factors, such as the CO₂ emissions of the grid operator or the share of renewable energies in the provision of electricity for a charging process, by means of a suitable cost function. The cost value KW in the embodiment described here is higher the higher the electricity costs are. Specifically, in step S3, the charging time window LF is modified such that at least one time period of the modified charging time window LF' lies before the start of the unmodified charging time window LF.The charging process according to the modified charging window LF' is designed such that the charging process falls entirely within the charging window LF' or encompasses the entire charging window LF', while simultaneously ensuring that the target charge level is reached no later than the departure time. Furthermore, the modified charging window LF' was chosen to be cost-neutral; that is, the cost value kW' resulting for charging within the modified charging window LF'—i.e., the electricity price for this charging process—is the same as, or potentially even less than, the cost value kW of the unmodified charging window.

[0033] In step S4, the modified charging time window LF' is transmitted to the user's vehicle. Subsequently, in step S5, the vehicle's charging process is carried out not with the original charging time window LF, but with the modified charging time window LF', while the departure time AZ and the target state of charge SL remain unchanged. In this way, at least part of the charging process is brought forward without negatively impacting the charging costs. By bringing forward the charging time window, the probability increases that, upon a corresponding command from the grid operator, the charging process of the vehicle in question can be interrupted by the specified interruption period from the server SE'.This is because it becomes more likely that when charging resumes after the interruption period, there will still be enough time available to reach the target charge level by the time the vehicle departs.

[0034] Figs. 3 to 5 These figures illustrate various scenarios for defining a charging time window. The abscissa represents the time of day t, and the ordinate represents the charging power P of the traction battery in a corresponding vehicle. In all figures, a block with diagonal hatching indicates the charging process (i.e., the power consumption) of the traction battery, and a dotted block indicates the charging time window. It is important to note that the height of the charging time window block does not represent the charging power P. Rather, only the width of the corresponding dotted block is relevant, as it corresponds to the size of the charging time window.

[0035] Fig. 3 This shows charging with the charging time window LF originally stored in the vehicle. The vehicle was connected to the power grid at time ST (i.e., 8:00 AM). The departure time AZ was set by the vehicle user to 6:00 PM. According to the charging time window, the charging process is selected such that it begins at 12:00 PM and ends at 5:00 PM when the target charge level is reached, which in this embodiment is 100%. The charging process is longer than the charging time window because the target charge level has not yet been reached at the end of the charging time window at 3:00 PM. In the scenario of Fig. 3 The electricity price is cheapest during the charging time window LF; in other words, the electricity price is more expensive outside the charging time window LF than within the charging time window. Furthermore, how can one... Fig. 3If detected, a degradation of the traction battery occurs towards the end of the charging process, i.e., the power consumption decreases significantly towards the end of the charging process.

[0036] Fig. 4 Figure 1 shows a modification of the charging time window LF carried out using the inventive method, resulting in a modified charging time window LF' which is divided into an earlier time segment A1 and a later time segment A2. The charging time window LF' was obtained such that the charge is attached to the end of the charging time window LF of the Fig. 3 The subsequent charging phase, in which no degradation has yet occurred, is brought forward to the point ST when the vehicle is connected for charging. The charging process with the charging time window LF' is cost-neutral, because in the section A2, which corresponds to the charging time window LF of the Fig. 3If this is the case, charging continues without degradation. In other words, the cost of charging using the charging time window LF' is the same as for the charging time window LF of the Fig. 3 For comparison, in Fig. 5 A modification of the charging time window was shown, which – in contrast to the method according to the invention – leads to an increase in the costs of the charging process. Fig. 5 The modified charging window is labeled LF" and comprises sections A1' and A2'. A larger section A1' of the charging process was used than in the original. Fig. 4 The charging window is brought forward to time ST. As a consequence, the latter part of section A2' of the charging window LF" falls within the period of vehicle battery degradation. Therefore, less charging occurs during the period of low electricity prices, resulting in increased electricity costs.

[0037] In Fig. 6 is generally represented in a diagram analogous to the preceding ones. Figures 3 to 5The shift in a loading window due to a pause in the loading process is illustrated. The duration of the pause is indicated by the horizontally hatched bar and labeled T. The pause in the loading process is triggered by a command from the server SE'. Fig. 1 The command specifies by how much the charging power of the vehicles is to be reduced. In the event that a charging process is suspended, a fixed suspension period of one hour is predefined. In the scenario of Fig. 6 The charging window originally covered the period T. Due to the interruption of the charging process, the time window was then shifted into the future. This shifted time window is the LFN time window. Fig. 6During the charging process, only a portion of the time window is utilized. This is because a buffer is added when defining the shifted charging window (LFN), which compensates for a lower predicted charging efficiency of the corresponding vehicle battery. This buffer prevents the vehicle from starting to charge before the actual charging window has begun due to an insufficient charging time window.

[0038] In a further embodiment of the inventive method, the charging process is also stopped in vehicles of the vehicle pool for which no charging time window is defined, but which are in so-called instant charging mode. According to this mode, the vehicle is charged immediately after being connected to the power grid, without regard to charging time windows or departure times, until it reaches the target state of charge. In this case, when charging is interrupted by a command from the server SE, a charging time window and a fictitious departure time are defined. The charging process is again designed such that the charging time falls within or encompasses the charging time window, and at the same time, it is ensured that the target state of charge is reached no later than the departure time.

[0039] The in Fig. 1The stationary battery storage system SB shown here is only used in the embodiment described here if the power reduction specified by the command of server SE cannot be covered by the batteries of the vehicles in the vehicle pool. In this case, the desired reduction in power consumption is achieved by drawing power from or feeding power back into the grid.

[0040] In one variant of the method according to the invention, a quota, i.e., a number of consecutive commands, is specified that are sent from the power grid to the control system to reduce power consumption. Once this quota is reached, the correspondingly modified charging time windows are reset to the original settings of the vehicle users.

[0041] The embodiments of the invention described above offer a number of advantages. In particular, they enable the charging of a pool of vehicles to be controlled via a common control system in such a way that a large number of vehicles can interrupt their charging process when required by the power grid, without altering customer preferences regarding charging costs or the departure time of the respective vehicle. In this way, the vehicle pool can be used to effectively balance overloads in a power grid. Reference symbol list

[0042] 1 Vehicles 2 Smartphone CO Central control system SE, SE' Server SB Stationary battery storage PT Portal LF, LF', LF", LFN Charging time window AZ Departure time SL Target charge level t Time of day P Power ST Time of vehicle connection to the grid A1, A2, A1', A2' Sections of charging time windows T Time period of charging interruption

Claims

1. Method for controlling the electrical charging of a group of vehicles (1) which are electrically connected to a power grid of a power grid operator, wherein the respective vehicles (1) draw power from the power grid for charging a vehicle-side energy storage for driving the respective vehicle (1), wherein a central control system (CO) can communicate with the respective vehicles (1) of the group as well as with a server (SE') of the power grid operator, wherein the central control system (CO) can suspend the charging of at least a part of the vehicle-side energy storages in response to a received reduction command which originates from the server (SE') of the power grid operator and specifies a power amount by which the power consumption of the group of vehicles (1) from the power grid is to be reduced, wherein • for one or more specific vehicles (1) of the group, a charging time window (LF), a departure time (AZ) and a target state of charge (SL) of the vehicle-side energy storage at the departure time (AZ) are respectively predetermined, wherein during the charging process of the vehicle-side energy storage of the respective specific vehicle (1) according to the charging time window (LF) a charging time criterion is fulfilled, so that the charging process lies entirely within the charging time window (LF) or comprises the entire charging time window (LF) and at the same time it is ensured that the target state of charge (SL) is reached at the latest at the departure time (AZ), wherein a cost value (KW) for the charging time window (LF) is predetermined according to a cost function which indicates a cost level depending on the charging process according to the charging time window (LF); characterized in that • the charging time window (LF) and the departure time (AZ) and the target state of charge (SL) for a respective specific vehicle (1), which are predetermined, are user-specific data which a user of the respective specific vehicle (1) has entered on a terminal device (2), wherein these data are transmitted from the terminal device (2) to the central control system (CO); • the central control system (CO) transmits to a respective specific vehicle (1) of at least a part of the specific vehicles (1) a modified charging time window (LF'), whereupon the charging process is carried out according to the modified charging time window (LF') under fulfilment of the charging time criterion with unchanged departure time (AZ) and target state of charge (SL), wherein the modified charging time window (LF') comprises at least one time section which lies before the beginning of the non-modified charging time window (LF) and wherein the cost value (KW') according to the cost function for the modified charging time window (LF') is equal to or smaller than the cost value (KW) for the non-modified charging time window (LF).

2. Method according to claim 1, characterized in that the cost function is dependent on the monetary electricity costs for the charging process according to the charging time window (LF, LF') and / or on the exhaust gas quantity which is generated by the power grid during the charging process according to the charging time window (LF, LF') and / or on the proportion of renewable energies which are used by the power grid during the charging process according to the charging time window (LF, LF'), wherein the cost level according to the cost function is greater the greater the monetary electricity costs and / or the exhaust gas quantity is and / or the smaller the proportion of renewable energies is.

3. Method according to one of the preceding claims, characterized in that in the case that the central control system (CO) suspends the charging of the vehicle-side energy storage of a specific vehicle (1) in response to a reduction command, a new charging time window (LFN), which deviates from the currently used charging time window (LF, LF'), is transmitted to the specific vehicle (1), wherein the beginning of the new charging time window (LFN) lies after a predetermined period of suspension of charging and otherwise the charging process according to the new charging time window (LFN) fulfils the charging time criterion with unchanged departure time (AZ) and target state of charge (SL).

4. Method according to claim 3, characterized in that in the new and / or the predetermined charging time window (LFN) a buffer is contained which takes into account a charging efficiency reduced compared to an expected charging efficiency of the vehicle-side energy storage, in order to prevent the vehicle-side energy storage from beginning charging before the beginning of the new charging time window (LFN).

5. Method according to one of the preceding claims, characterized in that, after a predetermined number of reduction commands have been processed by the central control system (CO), all modified charging time windows (LF') are reset to the predetermined charging time windows (LF).

6. Method according to one of the preceding claims, characterized in that a stationary energy storage system (SB) is connected to the power grid, which is controlled by the central control system (CO) in such a way that in the case that the reduction of the power consumption of the group of vehicles (1) by the power amount according to a reduction command cannot be achieved exclusively by suspending the charging of energy storages of respective vehicles (1), the power consumption of the stationary energy storage system (SB) from the power grid is reduced or the power output of the stationary energy storage system (SB) into the power grid is increased, so that the reduction of the power consumption of the group of vehicles (1), which is achieved by suspending the charging of energy storages of respective vehicles (1), plus the amount of the reduction of the power consumption or the increase of the power output of the stationary energy storage system (SB) corresponds to the power amount according to the reduction command.

7. Central control system for controlling the electrical charging of a group of vehicles (1) which are electrically connected to a power grid of a power grid operator, wherein the respective vehicles (1) draw power for charging a vehicle-side energy storage for driving the respective vehicle (1), wherein the central control system (CO) can communicate with the respective vehicles (1) as well as with a server (SE') of the power grid operator, wherein the central control system (CO) can suspend the charging of at least a part of the vehicle-side energy storages in response to a received reduction command which originates from the server (SE') of the power grid operator and specifies a power amount by which the power consumption of the group of vehicles (1) from the power grid is to be reduced, wherein the central control system is configured to carry out a method according to one of claims 1 to 6.