METHOD FOR CHARGING AN ELECTRIC VEHICLE

Description

[0001] The invention relates to a method for charging an electric vehicle, a system for charging an electric vehicle, a charging point and a computer program product.

[0002] Electromobility requires a widespread supply of charging points where electric vehicles can be charged. Electric vehicles can include cars, trucks, bicycles, electric scooters, and many more. To establish the necessary infrastructure, special charging stations connected directly to the public power grid can be used. However, this seems impractical, especially for private use and applications such as shopping centers and parking garages, as operators would need an additional connection to the public power grid in addition to the existing "house connections."

[0003] A house connection is defined as the connection point between the utility company's electrical lines and the lines of the building's consumers. "House," or "consumer," or "building," is to be understood generally in the context of this description and is not limited to private properties such as single-family homes, but also includes the parking garages, shopping centers, apartment buildings, and public facilities already mentioned as examples.

[0004] For example, US2011133693 A1 discloses a charging station for vehicles with load management.

[0005] It is known from KR 101 142 728 B1 that an overcurrent is detected locally at a charging device and the charging process is terminated in this case.

[0006] US 2011 / 095723 A1 also deals with the problem of overcurrent protection and discloses that a charging station monitors the current strength and, if an overcurrent is detected, stops the supply of electrical energy to an electric vehicle.

[0007] EP 0 949 733 A2 relates to an electrical protective switching device which is capable of communication via a data bus.

[0008] US 2016 / 236584 A1 discloses a system for generating a local autonomous response to a state of an electrical grid by electric vehicle charging stations, comprising: a first electricity meter for reading current, frequency, or voltage from a first electricity supply line to an electric vehicle charging station; a second electricity meter for reading current, frequency, or voltage from the electrical grid supplying the plurality of electric vehicle charging stations; a third electricity meter for reading current, frequency, or voltage from a third electricity line from one or more renewable generators;and an electric vehicle charging controller operatively coupled to the first electricity meter, the second electricity meter, the third electricity meter, and the electric vehicle charging stations and operable to obtain readings from the first electricity meter, the second electricity meter, and the third electricity meter and to control the electric vehicle charging stations based on the obtained readings.;

[0009] US 2020 / 023 747 A1 discloses an apparatus for charging a battery of an electric vehicle, configured to determine an energy charging plan for charging the electric vehicle from a microgrid based on charging preference information for the electric vehicle, as well as energy consumption information for devices on the microgrid and alternative energy resource information indicating the availability of electrical energy to supply the microgrid from an alternative energy resource on the microgrid, received via a communication network. A charging instruction signal for charging the electric vehicle from the microgrid according to the energy charging plan can be transmitted via the communication network.

[0010] US 2013 / 026986 A1 discloses a method including receiving a plurality of electric vehicle charging requests, receiving a plurality of power requests for additional electrical loads, and controlling the charging of the electric vehicles in conjunction with the plurality of electric vehicle charging power requests. Various examples include modulating the charging of one or more electric vehicles to maintain the total power consumed by the electric vehicles and a plurality of additional electrical loads below a power consumption threshold.

[0011] US 2016 / 137087 A1 discloses a power system including an electric vehicle supply equipment (EVSE). The EVSE includes a communication gateway that allows a user to access the internet via an EVSE server. In some embodiments, the EVSE enables communication with other smart devices and / or communication of a status of loads connected to a load center. The user or the utility provider can perform energy management and home automation tasks via the EVSE server using the EVSE's communication gateway and send control signals to smart devices via the EVSE. The EVSE can also provide a protection mechanism for smart devices connected to the load center in case of emergencies such as power outages or power grid surges.

[0012] The invention is based on the object of creating an improved method for charging an electric vehicle, a corresponding system, a charging point, and a computer program product. The objects underlying the invention are achieved by the features of the independent patent claims. Preferred embodiments of the invention are specified in the dependent patent claims.

[0013] A method is specified for charging an electric vehicle at one charging point of a set of charging points via an electrical building connection supplied with mains voltage. The electrical building connection is electrically connected to the (public) supply network, for example of an energy supplier. The charging points are connected to the electrical building connection via a power cable and to an authorization server via a network cable, wherein a current measuring device continuously determines the current currently flowing at the building connection and sends information about this to the charging points by means of serial data transmission as a bus signal via the network cable. The method comprises, by the charging point of the set of charging points: receiving a charging authorization for the electric vehicle from the authorization server via the network cable using an internet protocol;In response to receiving the charging authorization, performing a charging process of the electric vehicle, wherein the charging process comprises providing the power transported from the building connection via the power cable to the electric vehicle as charging current; at least during the charging process, checking whether the bus signal indicates a current overload at the building connection, and if the current overload is signaled, stopping the charging process.

[0014] The network cable thus serves both to transmit data using internet protocols such as FTP, HTTP, or HTTPs over TCP / IP, and to transmit the serial bus signal. While the internet protocol enables direct communication with the internet, for example, thus enabling a particularly simple and convenient connection of charging points to the internet, serial data transmission could be used for a very fast and virtually interference-free transmission of information regarding the current flowing at the building's power supply.

[0015] The described method could have the advantage that the charging points can be securely connected to the building connection with minimal wiring effort. "Secure" in this case means that, due to the speed of data transmission inherent in a serial bus system, the risk of an overload occurring at the building connection can be minimized. For residential building connections, for example, the connection is only dimensioned so that a maximum rated current of at least 63 A can be used to protect against overload via current protection devices. This is only an example and in practice varies from region to region and building type. If consumers in the building are active at the same time as vehicles are charging, this could quickly lead to an overload situation.

[0016] For example, it is conceivable that one or more vehicles are currently charging at the charging point or the various charging points and then one or more large energy consumers in the house are suddenly switched on. In this case, the current measuring device should be able to detect the increase in power consumption in the millisecond range, for example in a period of between 0.5 ms and 10 ms, and use the serial bus communication to stop the charging processes at the charging points. The speed of the serial bus communication should be high enough that the charging load reduction is adjusted quickly before a (relatively slow-acting) fuse in the building connection, such as a fuse in the building connection, is triggered. The fuse can also be designed as a contactor or include one.

[0017] Preferably, the determination of the current power consumption and the serial data transmission take place in real time. Bus cycle times of less than 20 ms are preferred, particularly less than 10 ms or even 5 ms. The distance to the units that can stop the charging process should be no more than 50 m long, preferably no more than 30 m long, and more preferably no more than 15 m.

[0018] If, for example, the fuse / contactor of the building connection were to trip after a predetermined period of time (e.g., 300 ms) due to an overload, this tripping should be prevented by ensuring that the total time required for recording power consumption, detecting the change (increase) in power consumption, transmitting the relevant information to the charging point, and stopping charging at the charging point does not exceed the predetermined time period. The charging point preferably has a suitable interface for the serial (real-time) data bus.

[0019] Alternatively, charging can also be interrupted outside of the charging points, at a power supply point to one or more charging points, preferably electrically closer to the fuse / contactor than the charging point itself. This allows for an even faster response. This power supply point, as an alternative unit for stopping the charging process, should then be coupled to the serial (real-time) data bus and have an appropriate interface.

[0020] The process of recording the power consumption and its change on the one hand and that of stopping on the other hand can be implemented or triggered in all described cases by a microprocessor, microcontroller, or the like, whereby the microprocessor or microcontroller operates with a correspondingly fast clock speed (e.g. between 200 Hz and 2 MHz or 2 MHz and more).

[0021] Since the network cable in question not only supports serial data transmission but also communication using the Internet Protocol, it is possible to control and supply the charging points with additional information with the aforementioned minimal wiring effort. This includes, in particular, receiving the aforementioned charging authorization from the electric vehicle.

[0022] For serial data transmission, for example, a differential signal (e.g. +-24V) transmitted over two wires of the network cable can be used. The slew rate should be limited here. This means that at least 300 baud is available for data transmission. Symmetrical signal transmission could have the advantage of ensuring particularly high tolerance to interference, which cannot be guaranteed with conventional data transmission using TCP / IP and Internet protocols. It is conceivable that the two wires of the network cable used for differential signal transmission could also be used simultaneously to transmit data using the Internet protocol.

[0023] In another variant, to increase safety, the charging point could be configured to stop a charging process even if it no longer receives a bus signal. This could result from a faulty current measuring device or a faulty network cable. In any case, it is ensured that a charging process only takes place if a reliable statement can be made regarding the current flowing at the building connection and the current does not exceed a predetermined maximum value.

[0024] According to one embodiment, the method further comprises providing a control device, wherein the control device also receives the bus signal, wherein the control device assigns, in particular individually, a maximum charging power to be used to the charging point via the internet protocol or by means of serial data transmission via the network cable. The maximum charging power to be used could, for example, be based on the fact that the building always reserves a predetermined buffer for additional power consumption by internal consumers.

[0025] This serial data transmission can take place using the same bus topology and, for example, the same bus protocol as used by the current measuring device to communicate the information regarding the current flowing at the building connection.

[0026] In principle, the control device can be a standalone module that can be installed once or multiple times in the overall system, independent of the charging points. Preferably, however, the control device is integrated into one of the charging points, or even into several or all of the charging points. The control device determines the maximum charging power to be used based on the current power consumption of the building's connection using the bus signal.

[0027] This could have the advantage of allowing flexible charging of the electric vehicle without increasing the risk of an overload at the building connection. The control device knows the current currently flowing at the building connection and, ideally, also knows the maximum permissible current. The control device can, in particular, use the network cable and the internet protocol to individually instruct the individual charging points to use a specific maximum charging current, thus ensuring that the building connection is not overloaded despite the charging processes.

[0028] In addition, the control device optionally knows which of the charging points currently intends to charge an electric vehicle. It is therefore also possible, for example, for the control device to determine the maximum charging power to be used based on the charging processes currently in progress and / or even on the charging profiles of the vehicles being charged. If a vehicle's charging profile is such that, toward the end of a charging process, the charging current absorbed by the vehicle's battery steadily decreases over a longer period of time, the control device could, with this knowledge of the charging profile, assign a steadily increasing maximum charging power to another vehicle over the said period.However, all of this takes place within the limits of the charging points' permanent checks to see whether the bus signal indicates a power overload at the building connection, so that in the event of a power overload being signaled, any charging process can be stopped immediately.

[0029] According to one embodiment, each of the charging points can serve as the control device, with the charging point serving as the control device being a master charging point and the remaining charging points being slave charging points. The determination of which of the charging points is the master charging point can be made independently by randomly negotiating this property among the charging points. This could have the advantage of minimizing implementation effort, so that a system installer does not have to worry about which of the charging points serves as the master or slave.

[0030] However, it is also possible for the master charging point to be determined automatically according to a predefined scheme. Since the master charging point's role involves determining the maximum charging power to be used and thus a certain amount of data processing effort (computing load), this inevitably results in greater wear and tear on the master charging point compared to the slave charging points. A predefined scheme, such as changing the master status at predefined intervals, for example, weekly, distributes said wear and tear evenly across all charging points. This could minimize the overall risk of failure of an individual charging point due to high data processing load.

[0031] According to one embodiment, the electrical building connection is a three-phase connection with three outer conductors, wherein the power cable also has the three outer conductors and the supply network voltage of the supply network is made available to the charging points via the three outer conductors of the power cable. The current measuring device determines the current specifically for each of the outer conductors of the electrical building connection and the information comprises the respective current strength of the outer conductors or ratios of the current strengths of the respective outer conductors to one another. If the charging process is a single-phase charging process, the control device can assign the outer conductors of the power cable to be used for the charging process to the charging point via the Internet protocol, depending on the current strength or the ratios of the current strengths specifically determined for each of the outer conductors of the electrical building connection.

[0032] This could then have the advantage of minimizing the risk of excessive unbalanced loads, i.e., uneven loading of the outer conductors of the three-phase AC network. Since, depending on the vehicle type, only single-phase charging is used, the use of high currents without appropriate unbalanced load compensation could lead to large unbalanced loads. The described variant of unbalanced load compensation, using a combination of current measurement by the current measuring device and determination of the outer conductors to be used by the control device, could enable unbalanced load compensation in a very simple, cost-effective, and effective way. This is because the current measuring device already measures current for all three phases (i.e., outer conductors), and the control device, as the central instance for all charging points, has knowledge of the charging processes currently taking place.

[0033] According to one embodiment, the allocation of the outer conductors to be used is carried out in such a way that the current flow is as equal as possible for all outer conductors of the electrical building connection (e.g. difference max. 20%).

[0034] According to one embodiment, at least some of the charging points have an air interface for wireless communication with a mobile terminal. A charging request for the electric vehicle is received via one of the air interfaces. This charging request is then sent to the approval server using the Internet protocol, and the approval for charging is received from the approval server in response.

[0035] This could then have the advantage of reliably ensuring that the request for charging can be communicated by the electric vehicle being charged or by its user. An example of this would be the charging point being located in an underground car park, which inherently has neither mobile phone reception nor Wi-Fi reception. In this case, the air interface could be a so-called femtocell, i.e., a radio cell with minimal spatial extension, for example, according to the UMTS, LTE, or GSM standard. Or the air interface could be a Wi-Fi access point.

[0036] For example, the user could reliably communicate their desire to charge their electric vehicle to the charging point via a corresponding application, such as an application on their mobile phone. The air interface would receive this charging request for the electric vehicle and send it via the network cable using the Internet protocol to an authorization server. This server could be implemented, for example, on the Internet in a cloud or locally in the area of ​​the building with the electrical connection or even the charging points. After receiving the charging request, the authorization server could check whether the user or the electric vehicle is authorized for a charging process. Authorization could, for example, be made dependent on whether the user has paid money for it.

[0037] Depending on the release server's decision, either a loading release or no loading release is received from the release server. Depending on the release server's response, a corresponding loading process may or may not occur.

[0038] It should be noted that an air interface for wireless communication is generally understood to be any interface via which communication between the electric vehicle or a mobile device regarding an ongoing charging process of the electric vehicle can take place, in particular with the release server. The air interface can, for example, enable transmission methods via RFID, mobile radio, WLAN, Bluetooth, etc.

[0039] According to one embodiment, the current measuring device further determines a current flow direction of the current currently flowing at the building connection, wherein the current measuring device further sends information about the current flow direction as the bus signal via the network cable, wherein the charging power of the charging point is regulated depending on the current flow direction sent by means of the bus signal.

[0040] For example, if the building has the ability to generate its own electricity (e.g., wind power, solar energy), this self-generated electricity could either be used for internal use, including charging electric vehicles, or fed partially or even entirely into the public power grid via the building's electrical connection. By taking the direction of electricity flow into account, it could be ensured that, wherever possible, the self-generated electricity is primarily used for internal consumption. In other words, it is preferable that the direction of electricity flow from the public power grid is always towards the building. From an economic perspective, self-consumption of self-generated electricity is significantly more lucrative than feeding it back into the public power grid.

[0041] Since the power output of self-generated electricity, for example, from solar energy or wind power, is typically subject to strong fluctuations (short-term fluctuations in wind or cloud cover), taking the current direction into account, preferably in real time, can ensure that self-generated electricity is "used" as fully as possible during the charging process of electric vehicles. Using wind energy as an example, a gust of wind and the associated increase in the power output of self-generated electricity would immediately increase the charging power at one or more of the charging points. As soon as the wind subsides somewhat, meaning the power output of self-generated electricity is reduced, the charging power would also be reduced accordingly.

[0042] According to one embodiment, depending on the direction of current flow transmitted by the bus signal, either the charging point regulates its own charging power, for example, independently of the other charging points, or, preferably, the control device determines the maximum charging power to be applied to the charging points. For example, each charging point or the control device can adjust the charging power, for example, proportionally, depending on the bus signal until the direction of current flow signals a current flow toward the building connection.

[0043] According to one embodiment, the charging point has control electronics for carrying out the charging process, with the control electronics being supplied with power via the network cable. It is also possible for the control device to be supplied with power via the network cable. This variant, known as Power over Ethernet (PoE), could have the advantage of eliminating the need for a separate power supply cable for operating the charging points. The individual network cable therefore has multiple functions: communication via the Internet protocol, serial bus communication, and the power supply of the control electronics of the charging points. Communication via the Internet protocol enables, for example, communication between the charging points, communication with servers on the Internet, and / or communication with the control device.

[0044] Powering the control electronics via PoE could have the advantage of allowing the charging points to operate even without powering the power cable. This is helpful for safety reasons, as the control electronics in this case operate at a maximum of 12 V or 24 V, for example, whereas the power cable can carry up to 230 V.

[0045] According to one embodiment, the network cable is a twisted-pair cable, preferably at least in the Cat5 category, more preferably Cat6 or Cat7. A possible pin assignment for a Cat5 twisted-pair cable would be: Pin 1 Tx+, Pin 2 Tx-, Pin 3 Rx+, Pin 4 DC+, Pin 5 Diff+, Pin 6 Rx-, Pin 7 DC-, Pin 8 Diff-. Here, DC = direct voltage for PoE, Tx = data sender, Rx = data receiver, and Diff denotes the differential signal for serial data transmission.

[0046] Also described is a method for charging an electric vehicle at a charging point of a set of charging points via an electrical building connection supplied with mains voltage, wherein the charging point is connected to the electrical building connection via a power cable and to a power measuring device and an approval server via a network cable, wherein the method comprises, by the charging point of the set of charging points: receiving a charging approval of the electric vehicle from the approval server via the network cable using an internet protocol; in response to receiving the charging approval, carrying out a charging process of the electric vehicle, wherein the charging process comprises providing the power transported from the building connection via the power cable to the electric vehicle as charging current;at least during the charging process, checking whether a bus signal received by the current measuring device via serial data transmission over the network cable indicates a current overload at the building connection, and if the current overload is indicated, stopping the charging process.

[0047] Also described is a system for charging an electric vehicle at a charging point of a set of charging points via an electrical building connection supplied with mains voltage, wherein the system comprises the charging points and a current measuring device, wherein the charging points are connectable to the electrical building connection via a power cable and to an approval server via a network cable, wherein the current measuring device is designed to permanently determine the current currently flowing at the building connection and to send information about this to the charging points by means of serial data transmission as a bus signal via the network cable, wherein the charging point of the set of charging points is designed to: receive a charging approval of the electric vehicle via the network cable from the approval server using an internet protocol;In response to receiving the charging authorization, performing a charging process of the electric vehicle, wherein the charging process comprises providing the power transported from the building connection via the power cable to the electric vehicle as charging current; at least during the charging process, checking whether the bus signal indicates a current overload at the building connection, and if the current overload is signaled, stopping the charging process.

[0048] Also described is a charging point for charging an electric vehicle via an electrical building connection supplied with mains voltage, wherein the charging point is connectable to an electrical building connection and further charging points via a power cable and to a power measuring device and an approval server via a network cable, wherein the charging point is designed to: receive a charging approval of the electric vehicle from the approval server via the network cable using an internet protocol; in response to receiving the charging approval, carry out a charging process of the electric vehicle, wherein the charging process comprises providing the current transported from the building connection via the power cable to the electric vehicle as charging current;at least during the charging process, checking whether a bus signal received by the current measuring device via serial data transmission over the network cable indicates a current overload at the building connection, and if the current overload is indicated, stopping the charging process.

[0049] Also described is a computer program product with instructions executable by multiple distributed processors, wherein the execution of the instructions causes the processors to perform the method described above. The processors can be included, for example, in the current measuring device, the control device, and / or the charging points.

[0050] It should be noted that the embodiments of the invention described above can be combined with each other in any way, as long as the combined embodiments do not exclude each other.

[0051] In the following, embodiments of the invention are explained in more detail with reference to other drawings. They show: Fig. 1 a system for charging an electric vehicle with charging points and electrical building connection, Fig. 2 a current measuring device, Fig. 3 a charging point, Fig. 4 further details of a system for charging an electric vehicle, Fig. 5 a flowchart of a method for charging an electric vehicle.

[0052] In the following, similar elements are identified by the same reference numerals.

[0053] Figure 1shows a system for charging an electric vehicle 100 at one charging point of a set of multiple charging points. Charging is to take place via an electrical building connection 120 supplied with the supply voltage of a public power grid 122. The connection 120 is located in a building 114. Without limiting the generality, it is assumed in the following that the building 114 is a private residential building. The electrical building connection 120 is connected to the public power grid 120 via a power cable 124. A power line 108 connects the electrical building connection 120 to all charging points 102.

[0054] In addition to the charging points 102, the electrical building connection 120 also supplies electricity consumers 118 of the house, for example a cooking area, a washing machine, a tumble dryer, lamps, etc.

[0055] Figure 1further shows a current measuring device 112, which continuously determines the current currently flowing at the building connection 120 and sends information about this to the charging points via serial data transmission as a bus signal via a network cable 110. Via the network cable 110, the charging points 102 are able to communicate with an approval server 126 using an internet protocol. In the example of Figure 1, the approval server 126 is located in a cloud, thus accessible via the internet 106. However, it is also possible for the approval server to be integrated into one of the charging points.

[0056] The network cable 110 thus performs a dual function. On the one hand, the bus data is communicated, preferably in real time, from the current measuring device 112 to the charging points 102. On the other hand, the network cable 110 serves to communicate the charging points 102, in particular with the release server 126 and optionally with the Internet 106.

[0057] In the following, it is assumed by way of example that a driver of the electric vehicle 100 wishes to park his vehicle at the middle of the Figure 1 to refuel the three charging points shown with electricity. For this purpose, the driver of the vehicle 100 connects his vehicle, for example, using a charging cable 101, to the corresponding charging point 102. He could then send a charging request to the release server 126. For example, he has a corresponding application on his smartphone for this purpose. The smartphone could send the request to the release server 126 via an existing mobile telecommunications network. Optionally, it is possible for one or more of the charging points 102 to have an air interface which is connected to the Internet 106 via the network cable 110. Thus, it could be possible for the smartphone application to communicate with the release server 126 using the air interface.

[0058] Upon receiving the charging request, the authorization server 126 will check whether the user of the vehicle 100 is authorized to perform a charging process. Such a check could, for example, include a corresponding payment process. If the authorization server 126 determines that the user is authorized to charge their vehicle at the charging point 102, the authorization server 126 sends a corresponding charging authorization to the charging point 102 via the network cable 110 using an internet protocol. In response to receiving the charging authorization, the charging point will then perform the charging process of the vehicle 100. For this purpose, power will flow from the building connection 120 via the power cable 108 to the charging point 102 and from there to the vehicle 100. This results in the charging of a battery of the vehicle 100.

[0059] Meanwhile, the current measuring device 112 continuously determines the current currently flowing at the building connection 120. Information about this is sent to the charging point 102 via serial data transmission as a bus signal via the network cable 110.

[0060] If the bus signal now indicates a current overload at the building connection, the charging point 102 will automatically stop the charging process. One scenario in which such a case could occur would be, for example, the commissioning of incapable electrical consumers 118 in the building 114 while the charging process of the vehicle 100 is taking place. In this case, the total current flowing through line 124 would exceed the maximum load limit specified for the building connection. However, before the typically slow-blow main fuse, in particular the fuse of the building connection, can react and blow, the current measuring device 112 signals the current overload to the charging point 102 in real time. The charging point will therefore immediately stop the power supply for the charging process, thus preventing the main fuse from "tripping."

[0061] The overload can be signaled via a special bus signal. In this case, the current measuring device 112 determines whether an overload is present or not and sends the special bus signal in the event of an overload. Alternatively, discrete current measurements from the current measuring device 112 are communicated to the charging points via the bus signal. In the latter case, the charging points would need to know a limit value for the maximum permissible current flow detected by the current measuring device 112, which, if exceeded, would trigger shutdown.

[0062] Furthermore, Figure 1 an optional control device 104. This is in Figure 1 shown as a separate module and connected to the network cable 110. However, it is also possible for the control device 104 to be integrated into one or more of the charging points 102.

[0063] The control device 104 also receives the bus signal and is able to individually assign, for example, a maximum charging power to be used to each of the charging points 102 via the internet protocol or by means of serial data transmission via the network cable 110. The assignment is made depending on the current power consumption of the building connection 120, which the control device 104 determines based on the bus signal.

[0064] The control device 104 preferably knows the current and future charging processes at all charging points 102. Furthermore, the control device 104 knows, for example, the charging profiles of the corresponding vehicles 100 to be charged at the charging points 102. As a higher-level instance, the control device 104 can allocate the maximum current available at the building connection 120 to the individual charging points 102 as a charging current. In particular, if the charging power to be used is also assigned to the charging points 102 via the bus signal, the control device could react in real time to any fluctuations in the current available for charging processes at the building connection 120.

[0065] In Figure 1The optional variant is also shown, in which the house 114 has a solar panel 116. The solar panel 116 can convert solar energy into electrical power and make it available to the electrical consumers 118 and the charging points 102 via the building connection 120. Furthermore, the energy generated by the building can be fed back into the public power grid 122.

[0066] For example, the current measuring device 112 is capable of determining the direction of the current flowing at the building connection 120. This allows it to detect whether the additional power generated by the solar panel 116 is fed back into the power grid 122 or whether the power is used for internal consumption. Information about the direction of current flow can also be provided to the control device 104 and / or the charging points 102 via the bus signal.

[0067] The charging power of the charging points 102 can be regulated depending on the direction of current flow received via the bus signal. For example, during the day, when the sky is cloudy, a large portion of the power required to charge the vehicle 100 could be drawn from the public power grid 122. However, in the event of a gap in the clouds, the power generated by the solar panel 116 would suddenly increase, which, while the charging power of the vehicle 100 remains constant, would lead to the "excess" generated power being fed into the public power grid 122. Since self-consumption of the power is more economical than feeding it into the public power grid, the control device 104, for example, ensures that the charging power of the charging point 102 for charging the vehicle 100 is increased in response to the reversal of the current flow away from the house and back to the public power grid.For this purpose, the control device 104 communicates with the corresponding charging point via the network cable 110 and causes it to increase the charging power, i.e. the charging current.

[0068] Preferably, the charging power is increased within the upper limits of the charging current specified by the vehicle 100 until the current measuring device 112 again signals a current flow from the public power grid 122 to the building 114 via the bus signal.

[0069] Figure 2 shows a detailed view of the current measuring device 112. The current measuring device has an "ammeter" 200, which measures, for example, by means of a shunt or inductively, the electrical current flowing from the public power grid 122 to the building connection 120. The measurement is preferably carried out separately for each outer conductor of the cable connection 124.

[0070] In the Figure 2In the variant shown, the current measuring device 112 also has an optional power supply 202, which supplies power to the control electronics of the charging points 102 and optionally to other components such as the control device 104 using PoE technology. The serial interface 204 is used to transmit a differentiated signal, which provides the information about the current currently flowing at the building connection as a bus signal to the charging points 102 and optionally also to the control device 104.

[0071] Furthermore, the current measuring device has a processor and memory 206. The memory contains instructions which, when executed by the processor, cause the current measuring device to measure the current and to transmit the information thereon via the serial interface 204.

[0072] Figure 3shows an example of a charging point 102. The charging point 102 has a network interface 304, via which the charging point can communicate via the network cable 110 using an internet protocol, for example, with the internet 106 and the server 126. Furthermore, the network interface 304 serves to receive the bus signal from the current measuring device 112 via the network cable 110.

[0073] An optional air interface 306 serves to provide communication access to the release server 126. For example, the air interface 306 allows a user of the vehicle 100 ( Fig. 1), to connect their smartphone to the Internet 106 and thus to the server 126. The air interface 306 can, for example, be a WLAN interface. If, for example, the charging point 102 is located in a location where public mobile phone reception is not normally available (e.g., in an underground car park), a release request could still be sent to the release server 126 via the air interface 306. The air interface 306 is capable of enabling communication with the release server 126 and optionally also with the Internet 106 via the network interface 304 and thus via the network cable 110.

[0074] The charging point 102 further includes a processor and a memory 308. The memory 308 contains instructions executable by the processor, wherein the execution of the instructions by the processor causes the charging point 102 to initiate, for example, the charging process of the vehicle 100 and other actions disclosed in this description.

[0075] In the variant of the Figure 3The charging point 102 further comprises the control device 104. In addition to the processor and memory 300, which function analogously to the processor and memory 108 and 206, the control device 104 also comprises an interface 302. The interface 302 can, for example, be internally connected to the network interface 304 in the charging point 102. It serves to receive the bus signal from the current measuring device 112 and to communicate the charging power to be used by the charging point(s) 102 depending on the current power consumption of the building connection.

[0076] Figure 4 shows a variant of the system of Figure 1 , although some components have been omitted for clarity. Figure 4It should be noted that the building connection 120 is a connection in which the "power line" coming from the public power grid has three outer conductors. This is therefore a three-phase connection. The terms "phase" and "outer conductor" are used synonymously in the present disclosure.

[0077] The three outer conductors of the building connection 120 are made available to the charging points 102 as a power cable 108 with three outer conductors. The current measuring device 112 is designed, for example, to determine the current specifically for each of the outer conductors of the building connection and to transmit information about this as a bus signal via the network cable 110 to the charging points 102 (and optionally to the control device 104). There are several options for how the information regarding the current of the outer conductors is transmitted. One example variant involves transmitting absolute values ​​of the currents for each of the outer conductors. Another variant could be transmitting ratios of the current strengths of the respective outer conductors to one another.

[0078] Based on the information regarding the respective current strengths of the outer conductors, the control device 104 can now assign the outer conductor of the power cable 108 to the charging points 102 to be used for the respective charging process. This, of course, only applies if the corresponding charging process at the charging point does not require all three phases simultaneously, i.e., all three outer conductors of the power cable 108. An example of this would be a charging process of a vehicle 100 with only a single phase. This individual phase could be selected depending on which phase of the cable feed 124 at the building connection 120 currently has the lowest current load. The goal is for the control device to ensure that the most equal current flow results for all outer conductors of the building connection. "As equal as possible" in this context means, for example, a difference in the current flows of a maximum of 30%, preferably a maximum of 20%, between two outer conductors.

[0079] The Figure 5 shows various flowcharts of a method for charging an electric vehicle. The flowcharts are divided according to the modules that implement the methods shown in the flowcharts. Steps 500-504 describe steps of the current measuring device, steps 506-520 describe steps of the control device, and steps 522-528 describe steps of the charging point.

[0080] First, we will discuss the process on the current measuring device side. As discussed above, the measuring device measures the current flowing at the building connection either specifically for each phase conductor or overall. This corresponds to step 500. In step 504, information about the measurement result is transmitted as a bus signal via the serial interface of the current measuring device. It should be noted at this point that steps 505 and 504 are continuously performed by the current measuring device, i.e., in parallel with any process steps performed by the control device or the charging point.

[0081] The steps performed by the charging point are discussed below. In step 506b, the serial bus signal is received via the network cable. This signal contains the information sent in step 504. In step 508, the charging point checks whether the bus signal indicates a power overload at the building connection. If this is not the case, the process continues with step 506b. If an overload is detected, the process ends in step 510 with the charging point being shut down.

[0082] Similar to steps 500-504 in the current measuring device, steps 506b-510 are also permanently carried out cyclically at the charging point, at least when a charging process is currently being carried out by the charging point.

[0083] Steps 522-528 are also performed at the charging point. Steps 522-524 are optional and apply in particular to the case where a charging request can be received directly at the charging point. This is the case if the charging point has a corresponding air interface. After receiving the charging request in step 522, it is sent to the approval server via the network cable. Receiving a charging approval in step 526 is mandatory, which ensures that the actual charging process then starts in step 528.

[0084] Steps 506a-520 describe operations of the control device. The control device can be integrated into the charging point or installed separately. In step 506a, the control device receives the information sent via the serial interface via the network cable. In this respect, step 506a corresponds to step 506b.

[0085] Steps 512-514 and steps 516-518 can be implemented optionally and independently of one another. In step 512, it is assumed that the current measuring device at the building connection determines the current flowing at the building connection specifically for all three outer conductors. The information received in step 506a therefore contains data regarding the current flow of each outer conductor. Step 512 then checks whether there is an unbalanced load between the outer conductors. If this is the case, in step 514, one or more of the charging points currently carrying out a charging process is assigned a phase (one of the outer conductors) to be used for charging, so that the unbalanced load is minimized overall. Step 514 is followed by step 516, to which the method jumps immediately if step 512 does not result in a need for phase adjustment.

[0086] In step 516, the control device receives the charging power levels with which the charging points are currently refueling vehicles. Based on the power consumption of the building connection signaled via step 506a, a check is carried out in the following step 518 to determine whether an adjustment of the charging power is necessary for one or more of the charging points. An adjustment of the charging power could, for example, be signaled to one of the charging points if the charging profile of a charging process at another charging point signals that, for example, a continuous decrease in the charging current is to be expected over a certain period of time. This is the case with certain battery types, for example, at the end of a charging process. In this case, the now released charging power could be dynamically allocated to another charging point. This takes place in step 520 with the signaling of the adjustment of the charging power.

[0087] Another scenario for step 518 is, for example, that the bus signal indicates a current flow at the building connection, which should not exceed the "maximum total current." If, in this case, another charging process is pending at another charging point, the control device can specify via step 518 that the available maximum total current is distributed among the charging points currently involved in the charging process. This also occurs in step 520 with the signaling of the adjustment of the corresponding charging power. All of this can also be combined with consideration of the charging profiles of the vehicles to be charged, as described above, for example.

[0088] The variants described above can be combined with other elements to further improve the operation of charging points in particular. For example, it is possible to integrate a metering device into the charging points, which can also function as a residual current device and overcurrent protection device, e.g., based on the ADE7932 measuring chip.

[0089] To prevent misuse of the charging points, it should be ensured that the charging point housing can only be unlocked by authorized persons. Ideally, the charging points should be designed without a mechanical key lock. They can only be unlocked via electronic authentication using a key transmitted via the network cable. A servo motor could be used for this, which performs the mechanical unlocking using the transmitted key. This enables, for example, tamper-proof operation and cost-effective maintenance. The unlocking can involve the mechanical opening of the charging point for maintenance purposes. The power supply can be provided via PoE and thus the network cable. Even if the charging station does not have a regular power supply, a "manual" power supply via the network cable is possible, for example.starting from a neighboring charging station, ensure that the electronic lock can be opened.

[0090] Due to the high price of copper, it is to be assumed that there will be an increase in charging cable theft. To counteract this, charging points with charging cables could be secured with an integrated alarm system. As soon as someone shakes the charging point column too vigorously or the charging cable is disconnected, an alarm signal could be immediately sent to a control center or charging point operator. In addition, a photo or video can be recorded using the integrated camera. Theft and tamper protection could be provided by resistance measurement in the charging cable and / or a linear acceleration sensor in the charging head. The resistance measurement could, for example, measure a resistor installed between two wires of the charging cable at the end of the charging cable facing the vehicle to be charged (near the charging head or in the charging head itself).If the charging cable is torn or cut, the resistance measured between the said wires by the charging point will change its value, which could trigger an alarm and transmit the said alarm signal.

[0091] Other possible variants for charging points include: an integrated camera, vehicle identification by license plate, vehicle color, and vehicle type in the event of an alarm, detection and signaling of a blocked charging space, documentation of tampering or vandalism, detection of weather events, and support for authentication processes (2FA, 3FA). Even a scan of contract documents is conceivable, with the contract documents indicating the signatory's authorization to conduct a charging process at the charging point.

[0092] Those skilled in the art will understand that aspects of the present invention may be embodied as an apparatus, method, or computer program or computer program product.

[0093] Accordingly, aspects of the present invention may take the form of a purely hardware embodiment, a purely software embodiment (including firmware, in-memory software, microcode, etc.), or an embodiment combining software and hardware aspects, all of which may be referred to generally herein as a "circuit," "module," or "system." Furthermore, aspects of the present invention may take the form of a computer program product embodied by one or more computer-readable media in the form of computer-executable code. A computer program also includes computer-executable code. "Computer-executable code" may also be referred to as "computer program instructions."

[0094] Any combination of one or more computer-readable media may be used. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A "computer-readable storage medium," as used herein, includes a tangible storage medium capable of storing instructions executable by a processor of a computing device. The computer-readable storage medium may be referred to as a computer-readable non-transitory storage medium. The computer-readable storage medium may also be referred to as a tangible computer-readable medium. In some embodiments, a computer-readable storage medium may also be capable of storing data that allows it to be accessed by the processor of the computing device.Examples of computer-readable storage media include, but are not limited to: a floppy disk, a magnetic hard disk, a solid-state hard disk, flash memory, a USB flash drive, random access memory (RAM), read-only memory (ROM), an optical disk, a magneto-optical disk, and the processor's register file. Examples of optical disks include compact disks (CDs) and digital versatile disks (DVDs), for example, CD-ROM, CD-RW, CD-R, DVD-ROM, DVD-RW, or DVD-R disks. The term computer-readable storage medium also refers to various types of recording media that are suitable for being retrieved by the computing device over a network or communications link. For example, data may be retrieved via a modem, over the Internet, or over a local area network.Computer-executable code embodied on a computer-readable medium may be transmitted over any suitable medium, including, but not limited to, wireless, wired, fiber optic, RF, etc., or any suitable combination of the foregoing media.

[0095] A computer-readable signal medium may include a propagated data signal containing the computer-readable program code, for example, in a baseband signal or as part of a carrier signal (carrier wave). Such a propagated signal may be in any form, including, but not limited to, an electromagnetic form, an optical form, or any suitable combination thereof. A computer-readable signal medium may be any computer-readable medium, other than a computer-readable storage medium, that can transmit, disseminate, or transport a program for use by or in connection with an instruction-executing system, device, or apparatus.

[0096] "Computer memory" or "memory" is an example of a computer-readable storage medium. Computer memory is any memory directly accessible by a processor.

[0097] "Computer storage" or "data storage" is another example of a computer-readable storage medium. Computer storage is any non-transitory computer-readable storage medium. In some embodiments, computer memory may also be computer data storage, or vice versa.

[0098] A "processor," as used herein, includes an electronic component capable of executing a program- or machine-executable instruction or computer-executable code. Reference to the computing device including a "processor" should be interpreted to potentially include more than one processor or processing cores. The processor may, for example, be a multi-core processor. A processor may also refer to a collection of processors within a single computer system or distributed across multiple computer systems. The term computing device or computer should also be interpreted to potentially refer to a collection or network of computing devices or computers, each including a processor or processors.The computer-executable code may be executed by multiple processors, which may be distributed within the same computing device or even across multiple computers.

[0099] Computer-executable code may comprise machine-executable instructions or a program that causes a processor to perform an aspect of the present invention. Computer-executable code for performing operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object-oriented programming language such as Java, Smalltalk, C++, or the like, and conventional procedural programming languages ​​such as the "C" programming language or similar programming languages, and translated into machine-executable instructions. In some cases, the computer-executable code may be in the form of a high-level programming language or in a pre-translated form and used in conjunction with an interpreter that generates the machine-executable instructions.

[0100] The computer-executable code may run entirely on a user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on the remote computer or server. In the latter case, the remote computer may be connected to the user's computer by any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, over the Internet using an Internet service provider).

[0101] The computer program instructions can be executed on one or more processors. In the case of multiple processors, these can be distributed across several different entities (e.g., clients, servers). Each processor could execute a portion of the instructions intended for the respective entity. Therefore, when referring to a system or method that encompasses multiple entities, the computer program instructions are understood to be adapted to be executed by a processor assigned to or associated with the respective entity.

[0102] Aspects of the present invention are described with reference to flowchart illustrations and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the invention. It is noted that each block or portions of the blocks of the flowchart illustrations, and / or block diagrams may be implemented by computer program instructions, optionally in the form of computer-executable code. It is further noted that combinations of blocks may be combined in different flowchart illustrations, and / or block diagrams if they are not mutually exclusive.These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing device to produce a device such that the instructions executed via the processor of the computer or other programmable data processing device produce means for performing the functions / steps defined in the block or blocks of the flowcharts and / or block diagrams.

[0103] These computer program instructions may also be stored on a computer readable medium that can direct a computer or other programmable data processing apparatus or other apparatus to function in a particular manner such that the instructions stored on the computer readable medium produce a manufactured article, including instructions that implement the function / step specified in the block or blocks of the flowcharts and / or block diagrams.

[0104] The computer program instructions may also be stored on a computer, other programmable data processing device, or other device to cause a series of process steps to be performed on the computer, other programmable data processing device, or other device to produce a computer-executed process, such that the instructions executing on the computer or other programmable device produce methods for implementing the functions / steps defined in the block or blocks of flowcharts and / or block diagrams. List of reference symbols

[0105] 100Vehicle 101Charging cable 102Charging point 104Control device 106Internet 108Power line / power cable 110Network cable 112Current measuring device 114Building 116Solar panel 118Power consumer 120Building connection 122Public power grid 124Supply line to the building 126Server 200Ammeter 202Power supply unit 204Serial interface 206Processor, memory 300Processor, memory 302Interface 304Network interface 306Air interface 308Processor, memory

Claims

1. A method for charging an electric vehicle (100) at a charging point (102) of a set of charging points (102) via an electric building connection supplied with supply mains voltage, wherein the charging points are connected to the electric building connection (120) via a power cable (108) and to an authorisation server (126) via a network cable (110), wherein a current measuring device (112) permanently determines the current currently flowing at the building connection (120) and sends information about this by means of serial data transmission as a bus signal via the network cable (110) to the charging points (102), wherein the method comprises using the charging point (102) of the set of charging points (102): - receiving a charging authorisation for the electric vehicle from the authorisation server (126) via the network cable (110) using an Internet protocol, wherein the network cable thus serves simultaneously for the transmission of data using the Internet protocol via TCP / IP and for the transmission of the serial bus signal, - in response to receiving the charging authorisation, carrying out a charging process of the electric vehicle (100), wherein the charging process comprises providing the current transported from the building connection (120) via the power cable (108) to the electric vehicle as charging current, - at least during the charging process, checking whether the bus signal indicates a current overload at the building connection (120) and, if a current overload is signalled, stopping the charging process.

2. The method according to claim 1, wherein the determination of the current power consumption and the serial data transmission take place in real time.

3. The method according to claim 1 or 2, wherein the method further comprises providing a control device (104), wherein the control device (104) also receives the bus signal, wherein the control device (104) assigns a maximum charging power to be used to the charging point (102) via the Internet protocol or by means of serial data transmission via the network cable (110), wherein the control device (104) determines the charging power to be used as a function of the current power consumption of the building connection using the bus signal.

4. The method according to claim 3, wherein the control device (104) further determines the maximum charging power to be used in dependence on: - charging processes currently taking place at the charging points (102) and / or - charging profiles of the vehicles to be charged.

5. The method according to claim 3 or 4, wherein each of the charging points may serve as the control device (104), wherein the charging point (102) serving as the control device (104) is a master charging point (102) and the remaining charging points are slave charging points.

6. The method according to claim 5, wherein the determination of which of the charging points is the master charging point (102) is carried out randomly or according to a predefined scheme.

7. The method according to one of preceding claims 3-6, wherein the electrical building connection (120) is a three-phase connection with three outer conductors, wherein the power cable (108) also has the three outer conductors and the supply mains voltage is made available to the charging points (102) via the three outer conductors of the power cable (108), wherein the current measuring device (112) determines the current specifically for each of the outer conductors of the electrical building connection and the information comprises the respective current intensity of the outer conductors or ratios of the current intensities of the respective outer conductors to one another, wherein, if the charging process is a single-phase charging process, the control device (104) assigns the outer conductors of the power cable (108) to be used for the charging process to the charging point (102) via the Internet protocol in dependence on the current strength determined specifically for each of the outer conductors of the electrical building connection or the ratios of the current strengths, wherein optionally the outer conductors to be used are assigned in such a way that the current flow for all outer conductors of the electrical building connection is as equal as possible.

8. The method according to any one of the preceding claims, wherein at least some of the charging points have an air interface for wireless communication with a mobile terminal, wherein a charging request for the electric vehicle is received via one of the air interfaces and is then sent to the authorisation server (126) using the Internet protocol, wherein the charging authorisation is received as a response thereto from the authorisation server (126).

9. The method according to any one of the preceding claims, wherein the current measuring device (112) further determines a current flow direction of the current currently flowing at the building connection (120), wherein the current measuring device (112) further transmits information about the current flow direction as the bus signal via the network cable (110), wherein the charging power of the charging point (102) is controlled in dependence on the current flow direction transmitted by means of the bus signal.

10. The method according to claim 9, wherein, depending on the direction of current flow transmitted by means of the bus signal - the charging point (102) controls the charging power or - the control device (104) determines the maximum charging power to be used.

11. The method according to any one of the preceding claims, wherein the charging point (102) has control electronics for carrying out the charging process, wherein the power supply to the control electronics is provided via the network cable (110).

12. A charging point (102) for charging an electric vehicle (100) via an electrical building connection supplied with supply mains voltage, wherein the charging point (102) is connectable to an electrical building connection (120) and further charging points (102) via a power cable (108) and to a current measuring device (112) and an authorisation server (126) via a network cable (110), wherein the charging point (102) is configured for: - receiving a charging authorisation for the electric vehicle from the authorisation server (126) via the network cable (110) using an Internet protocol, - in response to receiving the charging authorisation, carrying out a charging process of the electric vehicle (100), wherein the charging process comprises providing the current transported from the building connection (120) via the power cable (108) to the electric vehicle as charging current, - at least during the charging process, checking whether a bus signal received from the current measuring device (112) by means of serial data transmission via the network cable (110) signals a current overload at the building connection (120), wherein the network cable thus serves simultaneously for the transmission of data using the Internet protocol via TCP / IP and for the transmission of the serial bus signal, and, if a current overload is signalled, stopping the charging process.

13. A system for charging an electric vehicle (100) at a charging point (102) of a set of charging points (102) via an electrical building connection supplied with supply mains voltage, wherein the system comprises the charging points and a current device (112), wherein the charging points are configured in accordance with claim 12.

14. A computer program product comprising instructions executable by a plurality of distributed processors, wherein the execution of the instructions causes the processors to perform the method according to any one of the preceding claims 1-11.