Bi-directional vehicle charging apparatus and method

Abstract

A bidirectional electrical vehicle supply equipment (EVSE) comprises a control computer (202) and a plurality of communication, power interfaces, and a buffer battery (219). The EVSE (201) is electrically and communicatively connected with an electrical installation (206) of a home network and an electric vehicle (EV). In this 5 configuration the EV (213) can supply electric power to the electrical installation (206) for replacing grid power. A method operates the EVSE such that the buffer battery (219) is used alternatingly as a power sink and power source allowing the EV replacing grid power under conditions when conventional V2X systems cannot operate.

Description

[0001] Bi-Directional Vehicle Charging Apparatus and Method

[0002] Field

[0003] The present disclosure relates to relates to a bi-directional vehicle supply equipment and methods for charging of electrical vehicles (EV), in particular to selectively charging the electrical vehicle from the power grid or providing power from the vehicle’s battery to the charging point, also known as vehicle-to-home (V2H) when the vehicle can provide energy only locally to the home, vehicle-to-load (V2L) when the vehicle can provide energy only to a load, or vehicle-to-grid (V2G), when the vehicle can provide energy back to the public power grid. These three different configurations are also summarized with the term vehicle-to-something (V2X).

[0004] Background

[0005] An electric vehicle supply equipment (EVSE) is a piece of infrastructure that enables the charging of electric vehicles (EVs). It includes various components such as charging stations, connectors, and communication interfaces that ensure the safe and efficient transfer of electricity from the grid or a storage battery to the vehicle’s battery.

[0006] Implementation of V2X requires an EVSE that enables EVs communicating with the public power grid, home, and load, respectively for receiving electric energy from the grid or home and to provide electric energy back to the grid, home or load. For the sake of brevity electric energy is labelled in the following only energy without being unprecise because in the present application only electric energy is considered. a) Vehicle-to-home (V2H)

[0007] To operate a V2H configuration a bidirectional charger and additional equipment are required, including an energy meter (CT meter) that is capable of monitoring and measuring energy flow in two directions, namely from the power grid to the home and from the home to the power grid. The CT meter must be installed at the main power grid connection point of the home. If the V2H system and in particular the CT meter detects that the home draws energy from the grid, the CT meter may signal the bidirectional EV charger to discharge an equal amount of energy to replace the energy drawn from the grid assuming that the EV is connected to a charging point installed in the home and that its battery is sufficiently charged. Such action may be useful for reducing the power grid load in certain situations, e.g., when the power demand in a local section of the power grid is very high and the grid power generation is low, e.g., at times when the amount of renewable energy that is produced is low, and spare power utilities have not been fully activated for compensation. Powering the home from the EV’s battery may also be used for reducing the amount of energy drawn from the power grid during high-cost phases, notably in power grids that have dynamic energy pricing. V2H also allows consumers to provide electricity to their homes from their EVs’ batteries during a power grid outage. b) Vehicle-to-grid (V2G)

[0008] V2G functionality puts EV owners advantageously into the position to leverage their vehicles’ considerable battery capacity to sell electricity back to the grid during peak load. However, V2G functionality requires, firstly, vehicles and charging stations which are equipped and configured as described above regarding V2H systems. In addition to that, V2G requires, secondly, a data connection for enabling data communication with the power grid operator, for negotiating when energy shall be provided from the EV to the grid and how much. The data connection is necessary due to the power grid operator’s overall control of the power grid or power grid section, which ensures the power grid’s stability and prevents local or regional power grid shutdown due to severe imbalance between two or more power grid sections. Optionally, users can set a cap on how much power can be drawn to prevent overutilization of the battery, and they can further customize settings to choose to buy back electricity when grid energy prices are low and sell to the grid only at peak prices. c) Vehicle-to-load (V2L)

[0009] When operating in the V2L mode the EV serves as a power supply for a load connected to a power interface of the EV. To this end, the AC / DC converter aboard the EV can be used to provide AC current if the load needs it. A control unit monitors the operation of the EV as power source to prevent that the EV’s battery is depleted below a settable lower limit.

[0010] Despite the already existing concepts of using EVs as a source of energy, there still remains a desire for enhanced methods and apparatuses that further facilitate using an EV battery for supplying electric energy to a grid or a home through a charging point and to expand the opportunities of doing so. Summary of invention

[0011] The present invention presents three methods and correspondingly configured apparatus and / or systems that address the following problems in the afore-mentioned context:

[0012] 1) Some EVs have a relatively large power consumption when operating in a V2X mode. In order not to use too much of the electricity stored in the EV’s battery for simply maintaining the V2X mode in the EV, these EVs may be configured that the power provided by the EV must not fall below a lower limit preventing the V2X mode from having a too low efficiency. I.e., the V2X is only available when the entity that receives power from the EV requires or accepts more power than defined as the lower power limit.

[0013] For example, an EV may have a lower power limit of 400 W in V2X mode. Other examples for a lower power limit are 1500W or 3000W in V2X mode. Generally speaking, the lower power limit may be between 400W and 3000W, preferably between 1500W and 3000W. The maximum discharging power is for instance 10 kW. If a home that receives power from the EV has a power consumption of 200 W, or a power consumption of 500 W in the case of a lower power limit of the EV of 1500W, the EV may not be able to enter the V2X mode if providing the excess power to the grid is not possible, not permitted or permitted only under certain circumstances. The latter may be the case if only electricity that was generated CO2 neutral or CO2-free may be fed to the grid, e.g., for billing reasons, when so-called ‘green-electricity’ is sold at a higher price than electricity of unknown or unwanted provenience.

[0014] 2) Some EVs can only provide electricity to a home on all three phases simultaneously when in V2X mode. In this case, when the electricity grid in the home is loaded only on one or two of three phases, and when the electricity meter is not capable of determining the true consumption over all three phases but rather determines the consumption phase-accurate, the energy provided back to the home or the grid will not be properly measured.

[0015] For example, a one-phase appliance uses 600 W, and the EV provides 3 x 200 W in V2X mode. If the energy meter cannot measure currents going towards the grid and does not determine the sum of the currents going into the home and out of the home over all three phases, in which case the measured power would be zero (0). Rather, the energy meter would measure 600 W - 200 W = 400 W on the one phase, and the current going out into the grid, i.e., 2 x 200 W = 400 W would not be a valid compensation because the 400 W drawn from the grid would be sold at a higher price than the compensation for the 400 W provided to the grid.

[0016] 3) Some grid connections of customer premises may have a limited maximum power to ensure stability and reliability of the electrical grid. Another potential reason why exceeding a predetermined maximum power may be undesirable is that any power over said predetermined value has a much higher price attached to it.

[0017] 4) An isolated grid segment requires that one and only device determines the grid’s power properties, i.e., voltage and frequency. Such device is also referred to as grid master. If more than one DC-AC-converters are connected to such isolated grid segment, and all of these DC-AC-converters are mobile, i.e., may not always be connected to the isolated grid, such grid master is not defined, and the isolated grid may not be properly powered.

[0018] The problems presented above are addressed by the methods and apparatus presented hereinafter in the various aspects of the invention.

[0019] In accordance with a first aspect of the invention a bi-directional electrical vehicle supply equipment (EVSE) is presented. The EVSE comprises a control computer, first, second and third communication interfaces, first, second and third AC power interfaces, and one or more switches for selectively establishing and interrupting, respectively, an electrical connection between the EVSE and an electrical installation of a building or house connected to the first AC power interface, an electrical connection between the EVSE and an EV connected to the second AC power interface, and / or an electrical connection between the EVSE and a DC-AC-converter of a buffer battery connected to the third AC power interface. The buffer battery is a power battery for transitional storage of electricity.

[0020] All elements mentioned before are communicatively connected to the control computer, which receives signals and / or data related to their respective operation from the various elements and / or transmits control signals and / or data to the respective elements, during startup, operation and shutdown thereof.

[0021] The first power interface is configured for connecting the EVSE to an electrical installation, e.g., of a building or house, and may comprise, in addition to one or more power terminals, one or more sensor, signal or data terminals. The second power interface is configured for connecting the EVSE to an EV and may likewise comprise, in addition to one or more power terminals, one or more sensor, signal or data terminals.

[0022] The third power interface is configured for connecting the EVSE to a DC-AC- converter of a buffer battery and may likewise comprise, in addition to one or more power terminals, one or more sensor, signal or data terminals.

[0023] The first communication interface may be configured for communicating with an electrical installation to which the EVSE is connected. The communication may involve protocols such as those stipulated in ISO 15118, using a standard or advanced communication parameter set, or may be involve a low-level PWM communication, using a basic communication parameter set. The communication may run via the one or more data terminals of the first power interface and may be targeting a smart meter or a smart meter gateway associated with the electrical installation with which the ESVE is coupled.

[0024] The second communication interface may be configured for communicating with an EV to which the EVSE is connected, e.g., via a corresponding charging cable that has a communication line in addition to power connections. The communication may likewise involve protocols such as those stipulated in ISO 15118, for negotiating or setting bi-directional charging parameter sets for the AC / DC and DC / AC converter of the EV. The communication may run via the one or more data terminals of the second power interface.

[0025] The third communication interface may be configured for communicating with a DC-AC-converter of a buffer battery to which the EVSE is connected. The communication may involve protocols such as those stipulated in ISO 15118, using a standard or advanced communication parameter set, or may be involve a low-level PWM communication, using a basic communication parameter set. The communication may run via the one or more data terminals of the third power interface.

[0026] In one or more embodiments the EVSE further comprises a fourth communication interface configured for communicating with one or more power meters associated with one or more corresponding appliances that consume electrical energy when operated. The communication may be wired or wirelessly and may be direct or through a gateway device. The fourth wireless interface may include but is not limited to wireless communication via public wireless communication networks such as 5G, LTE, UMTS, GPRS and the like, or as stipulated in standards such as the IEEE802.11 family, the IEEE 802.15.1 family, the Bluetooth SIG standards, Zigbee, Z-Wave, LoRaWAN (ITU-T Y.4480) and the like.

[0027] In one or more embodiments the EVSE has a standardized household power outlet, and the control computer is configured for selectively enabling or disabling a V2L mode, i.e. , providing power to the standardized household power outlet from the EV’s battery.

[0028] In an advantageous embodiment of the EVSE the buffer battery has a capacity of 1 to 5 kWh and preferably between 1 .5 to 3 kWh. A buffer battery of that capacity has been found to represent a good cost versus benefit relation.

[0029] According to an aspect of the invention a method of operating electrical vehicle supply equipment (EVSE) according to the first aspect of the invention is suggested. The method comprises, after establishing physical connections between the EVSE and an EV:

[0030] - receiving information regarding a supply power level from the EV, wherein the supply power level aims at maximizing efficiency or aiming at exceeding a predetermined level of efficiency of the power transfer from the EV,

[0031] - receiving information representing a momentary power provided from a power grid into an electrical installation to which the EVSE is coupled, wherein the method further comprises, if the momentary power is equal to or higher than the supply power level:

[0032] - configuring a power converter of the EV in accordance with the momentary power, or, if the momentary power is lower than the supply power level:

[0033] - configuring the power converter of the EV in accordance with the supply power level,

[0034] - transferring power to the electrical installation in accordance with the momentary power, - transferring an amount of power corresponding to the difference between the momentary power and the supply power level to the buffer battery connected to the third AC power interface of the EVSE,

[0035] - terminating the transfer of power from the EV when the buffer battery reaches or exceeds a predetermined upper charging level,

[0036] - supplying an amount of power corresponding to the momentary power from the buffer battery, and

[0037] - terminating the transfer of power from the buffer battery and restarting the transfer of power from the EV when the charging level of the buffer battery reaches or falls below a predetermined lower charging level.

[0038] Advantageously, the method maximizes the efficiency of the power transfer from the EV even when the consumed power of a load remains below a minimum power that can be supplied by the EV by means of the buffer battery and a pulsed operation of the EV as energy source.

[0039] In accordance with an aspect of the present invention a further method of operating an EVSE in accordance with embodiments of the first aspect of the invention is presented. The method may in particular be executed in case EVs cannot operate in V2X mode under low load conditions, i.e. , cannot provide less power than a predefined lower power limit. The method comprises receiving, at the EVSE and from the EV, a lower power limit of the EV when operating in V2X mode and receiving information representing a momentary power provided from a power grid into an electrical installation to which the EVSE is coupled. If the momentary power is equal to or higher than the lower power limit the method further comprises configuring a power converter of the EV in accordance with the momentary power and transferring power to the electrical installation in accordance with the configuration. If the momentary power is lower than the lower power limit the method further comprises configuring the power converter of the EV in accordance with the lower power limit, transferring power to the electrical installation in accordance with the momentary power, and transferring an amount of power corresponding to the difference between the momentary power and the lower power limit to a buffer battery connected to the third AC power interface of the EVSE. The stored electrical energy can be used at a later point in time, even in the absence of the EV. Alternatively, if the momentary power is lower than the lower power limit, the method further comprises activating an appliance coupled to the electrical installation that consumes at least an amount of power corresponding to the difference between the momentary power and the lower power limit and transferring power to the electrical installation in accordance with the then momentary power. The activated appliance may be a water boiler or the like, which stores energy after conversion from electrical energy into a different form.

[0040] Transferring power to the buffer battery instead of drawing less power from the battery of the electric vehicle is more efficient because the buffer battery is designed for high efficiency for low discharging powers. In simple words, the battery of the electric vehicle is not optimized for low charging and / or discharging power.

[0041] In one or more embodiments of the method in accordance with the second aspect of the invention the information representing a momentary power provided from a power grid into an electrical installation to which the EVSE is coupled is received or updated at intervals or continuously, and wherein configuring the power converter of the EV and the transfer of power to the electrical installation are executed in accordance with the received or updated information.

[0042] Advantageously, the method may further comprise

[0043] - configuring the power converter of the EV in accordance with a supply power level aiming at maximizing efficiency or at exceeding a predetermined level of efficiency of the power transfer from the EV; and

[0044] - transferring the amount of power from the EV corresponding to the difference between the momentary power and the supply power level to the buffer battery;

[0045] - terminating the transfer of power from the EV when the buffer battery reaches or exceeds a predetermined upper charging level;

[0046] - supplying an amount of power corresponding to the momentary power from the buffer battery; and

[0047] - terminating the transfer of power from the buffer battery and restarting the transfer of power from the EV when the charging level of the buffer battery reaches or falls below a predetermined lower charging level.

[0048] In a preferred embodiment it has been found useful to continuously determine the power level aiming at maximizing efficiency or aiming at exceeding a predetermined level of efficiency of the power transfer from the EV.

[0049] In accordance with another aspect of the present invention another method of operating an EVSE in accordance with embodiments of the first aspect of the invention is presented. The method may in particular be executed in case the EV can provide electric energy only on three phases simultaneously and at equal power in each phase, and if the momentary load on the three phases in the electrical installation unequally distributed across the three phases. The method comprises receiving information representing a momentary load on each phase of an electrical installation to which the EVSE is coupled. The method further comprises configuring the power converter of the EV to provide power to all three phases of the EVSE in accordance with any one of the loads on any of the phases of the electrical installation, and for each phase that has a load that is lower than the power provided from the EVSE, transferring an amount of power corresponding to the difference between the load on that phase and the power provided from the EV to a buffer battery connected to the third AC power interface of the EVSE. Alternatively, the method further comprises activating an appliance coupled to the corresponding phase of the electrical installation that consumes at least an amount of power corresponding to the difference between the load on that phase and the power provided from the EV and transferring power to the electrical installation in accordance with the configured power on all three phases.

[0050] This method stores the difference between the power provided by the EV on each phase and the load on each phase in the electrical installation in a battery in a phase-accurate manner, thereby avoiding feeding back power into a power grid coupled to the electrical installation on one or more phases. The stored energy can be used at a later point in time, even in the absence of the EV.

[0051] In one or more embodiments the method in accordance with the third aspect of the invention further comprises receiving a lower power limit from the EV, configuring the power converter of the EV in accordance with the lower power limit of the EV, and transferring any power exceeding a momentary load on a phase to the buffer battery connected to the third AC power interface of the EVSE.

[0052] In accordance with a fourth aspect of the present invention a third method of operating an EVSE in accordance with embodiments of the first aspect of the invention is presented. The method may in particular be executed in case the power grid cannot provide more than a predetermined amount of power, or in case any power consumption above a predetermined level is charged at a higher price. The method comprises receiving information representing a momentary power provided from a power grid into an electrical installation to which the EVSE is coupled. If the momentary power exceeds a predetermined level the method further comprises providing power corresponding to the difference between a current load on the electrical installation and the predetermined level from a buffer battery connected to the third AC power interface of the EVSE. The method further comprises configuring one or more EVs connected to the EVSE to enter a V2X mode and configuring the power converters of the or more EVs connected to the EVSE to provide power to the electrical installation.

[0053] The buffer battery connected to the third AC power interface of the EVSE may preferably be configured for immediate reaction and may serve as intermediate power buffer that is active until the one or more EVs have come back from a standby mode and have entered the V2X mode, in which power is fed back from the respective EV’s battery.

[0054] In one or more embodiments of the method in accordance with the fourth aspect of the invention the power converters of the one or more EVs are configured to provide power in accordance with the respective V2X power capabilities, i.e. , maximum power of the vehicle’s DC-to-AC-converter and / or battery status, i.e., amount of energy that can be made available.

[0055] In one or more embodiments of the method in accordance with the fourth aspect of the invention the power converters of the one or more EVs connected to the EVSE are configured to provide more power than the current load on the electrical installation, and wherein the difference between the current load on the electrical installation and the power provided by the one or more EVs connected to the EVSE is transferred to the buffer battery connected to the third AC power interface of the EVSE.

[0056] In accordance with a fifth aspect of the present invention a fourth method of operating an EVSE in accordance with embodiments of the first aspect of the invention is presented. The method may in particular be executed when the electrical installation is isolated, i.e., is not coupled to a public power grid that acts as a grid master, providing a voltage level and a stable frequency. As mentioned earlier, in isolated networks, or off-grid networks, only one grid master can exist. As the grid master function is provided by a DC-to-AC-converter, any further DC-to-AC-converter that may be connected to the isolated electrical installation must be synchronized to the grid master. In case multiple EVs are connected to an EVSE of an isolated electrical installation the EVSE must determine the grid master and control all other EVs to synchronize to that grid master. The EVSE selects one EV as the grid master, establishes a stable isolated network, and only then adds further EVs to the isolated network, for providing power. Once the isolated network is fully up and stably running, electrical appliances requiring power can be activated, and the share of the power provided by each respective EV may be adjusted in accordance with the power requirements of the isolated network.

[0057] Accordingly, the method in accordance with the fourth aspect of the invention comprises, if the EVSE is coupled to an isolated electrical network, after establishing physical connections between the EVSE and one or more EVs, the steps of detecting EVs coupled to the EVSE, selecting an EV to act as grid master, configuring the selected EV to enter a V2X mode, configuring the power converter of the selected EV to provide power to the isolated electrical network, configuring one or more further EV coupled to the EVSE to enter a V2X mode, and configuring the power converters of the one or more further EVs to provide power to the isolated electrical network.

[0058] In one or more embodiments the method in accordance with the fifth aspect of the invention further comprises selectively activating electrical loads coupled to the isolated electrical network after one or more EVs are configured to provide power to the isolated electrical network.

[0059] In one or more embodiments the method in accordance with the fifth aspect of the invention further comprises receiving information about the maximum power capability and the available energy from the detected EVs after detection thereof.

[0060] In one or more embodiments the method in accordance with the fifth aspect of the invention further comprises determining a load on the isolated electrical network, and configuring one or more EVs to provide a respective share of the total power required for powering the load on the isolated electrical network. The respective share may be determined in accordance with the respective V2X power capabilities and / or battery status of each EV.

[0061] In one or more embodiments the method in accordance with the fifth aspect of the invention further comprises, if an EV is newly connected to the EVSE, receiving information about the maximum power capability and the available energy from the newly connected EV, determining a load on the isolated electrical network, and configuring one or more EVs to provide a respective share of the total power required for powering the load on the isolated electrical network. If an EV that is not the grid master is disconnected from the EVSE the method further comprises determining a load on the isolated electrical network, and configuring one or more remaining EVs to provide a respective share of the total power required for powering the load on the isolated electrical network.

[0062] In one or more embodiments the method in accordance with the fifth aspect of the invention further comprises, if an EV that is the grid master is disconnected from the EVSE, selecting a new grid master amongst the EVs remaining coupled to the EVSE, determining a load on the isolated electrical network, and configuring one or more EVs to provide a respective share of the total power required for powering the load on the isolated electrical network.

[0063] In the following an example for the method in accordance with the fifth aspect is provided. At least two vehicles are connected to the EVSE. These have registered when connected to the EVSE. In the event of a power failure in the electrical network the EVSE is connected to, the EVSE queries the vehicle data of the connected EVs. The at least two vehicles now send their vehicle data, i.e. , maximum power, maximum capacity, SoC, etc., to the EVSE. The EVSE now selects, acting as orchestrator, the vehicle with the highest capacity, e.g., in order to provide the minimum isolated network as network grid master. The other vehicles become network following vehicles. Subsequently connected vehicles are automatically declared as network following vehicles in the current orchestrator session. The EVSE permanently measures the grid connection point and orchestrates the power delivery from the connected vehicles. For example, if power of <12 kW is required, the power is supplied by the master vehicle alone, which has a maximum power of 12 kW. If the power demand rises above 12 kW, the EVSE orchestrates the network following vehicles to provide >2 kW, reducing the power of the grid master vehicle to <12 kW. When one of the network following vehicles leaves the orchestrated charging system, the EVSE only needs to invoke the power delivery orchestration algorithm again to distribute the total power amongst the remaining vehicles. When the master vehicle leaves the orchestrated charging system, the EVSE must select a new vehicle from the connected vehicles.

[0064] In accordance with a sixth aspect of the invention a control computer of an EVSE is presented. The control computer comprises one or more microprocessors, volatile and non-volatile memory, and one or more communication interfaces. The non-volatile memory stores computer program instructions which, when executed by the one or more microprocessors, configure the control computer execute one or more of the methods in accordance with the second to fifth aspects described hereinbefore.

[0065] The methods of operating an EVSE may be represented by computer program instructions which, when executed by a microprocessor, cause the microprocessor and / or control hardware components of the apparatus to execute one or more steps of the method in accordance with the second aspect of the invention as presented hereinbefore, or configure the computer system in accordance with the third aspect of the invention to execute one or more steps of the method in accordance with the second to fifth aspects of the invention as presented hereinbefore, respectively.

[0066] The computer program instructions may be retrievably stored or transmitted on a computer-readable medium or data carrier. The medium or the data carrier may by physically embodied, e.g., in the form of a hard disk, solid state disk, flash memory device or the like. However, the medium or the data carrier may also comprise a modulated electro-magnetic, electrical, or optical signal that is received by a computer by means of a corresponding receiver, and that is transferred to and stored in a memory of the computer.

[0067] At least some of the methods may also be useful in situations in which the total time for which an EV may be used in V2X mode is limited by the EV manufacturer. In this case, in order to have the maximum benefit from the EV’s capability of providing power to the grid or to an electrical installation, it may be beneficial to operate the EV in the V2X mode at a maximum power for a shorter time, buffering the excess energy in the buffer battery coupled to the EVSE, and stopping the EVs V2X mode while continuing powering the grid or electrical installation from the buffer battery. Doing so would reduce the operating time of the EV in V2X mode during each V2X session.

[0068] In at least some of the methods presented herein the EVs may also provide an indication at which power the efficiency of the V2X mode is highest, or above a predetermined level. In this case, the power provided to the electrical installation, grid or isolated electrical network by the respective EV may be adjusted accordingly: The buffer battery may store excess energy and solely provide power during certain periods, while the EVs are not providing power. The EVs are switched back into V2X mode whenever the energy stored in the buffer battery is insufficient, or the power of the buffer battery’s DC-to-AC-converter is insufficient. Brief description of the drawings

[0069] Exemplary embodiments of the present disclosure are illustrated in the drawings and are explained in more detail in the following description. In the figures, the same or similar elements are referenced with the same or similar reference signs. It shows:

[0070] Fig. 1 a schematic block diagram of a conventional V2X setup;

[0071] Fig. 2 a schematic block diagram a V2X setup according to the present disclosure;

[0072] Fig. 3 a characteristic curve of the charging and discharging efficiency of a battery of an EV;

[0073] Fig. 4 a schematic flow diagram of a method for extending usage of the battery of an EV in V2X environments, and

[0074] Fig. 5 a schematic block diagram of a control computer in accordance with the fifth aspect of the present disclosure.

[0075] Detailed description

[0076] Figure 1 illustrates schematically conventional concepts of V2G, V2H, and V2L functionalities in a single block diagram. A public power grid is symbolized by a mast 101 connected with a powerline 102 to a main house connection point 103 of a house 104. An electric vehicle (EV) 105 is connected with a charging station 106 configured to operate in a V2G, V2H, or V2L mode. The charging station is connected with the main house connection point 103. The charging station 106 is also directly connected with an electrical appliance 107 to supply it with energy from the EV 105 without passing through an electrical installation (home network) of the house 104. The charging station 106 is configured to operate in the V2G, V2H, or V2L mode depending on the settings of the charging station. The house 104 is further equipped with at least one photovoltaic module 108 and DC / AC converter (not shown) to supply energy to the electrical installation of the house 104 via the main house connection point 103.

[0077] Figure 2 shows a block diagram of a V2X set up 200 comprising an electrical vehicle supply equipment (EVSE) 201 according to the present disclosure. In one embodiment the EVSE 201 is implemented as a charging station and comprises a control computer 202, first, second, and third communication interfaces 203a-c, and first, second, and third power interfaces 204a-c.

[0078] An electrical installation 206 (home network of Figure 1 ) communicates through data lines 207a, 208a via the first communication interface 203a with the control computer 202. Power lines 209a, 210a connect to the electrical installation 206 with switches, which are represented in Figure 2 by a single switch symbol 212. The switches are configured to selectively connect the first, second, and third power interfaces 204a-c with one another in any combination including the option that no power interface 204a-c is connected with any other power interface.

[0079] In a similar fashion an electric vehicle (EV) 213 communicates through data lines 209b, 210b via the second communication interface 203b with the control computer 202. Power lines 209b, 210b connect the EV 213 with the switches 212. The EVSE 201 supplies and receives AC power and a single phase or three-phase AC electricity. For that reason, the EV 213 is provided with an internal AC / DC converter 214 to supply DC current for charging a battery 216 of the EV 213. The internal AC / DC converter 214 of the EV 213 works in both directions, i.e. the internal battery 216 of the EV 213 can provide AC power to the EVSE 201 .

[0080] An AC / DC converter 217 communicates through data lines 207c, 208c via the third communication interface 203c with the control computer 202. Power lines 209c, 210c connect the AC / DC converter 217 with the switches 212. A further power line 218 connects the AC / DC converter 217 with a buffer battery 219. The present disclosure is not limited to a specific capacity of the buffer battery but in a preferred embodiment the buffer battery capacity ranges from 1 to 5 kWh and more preferably between 1 .5 to 3 kWh. A buffer battery 219 with a capacity of 1 .5 to 3 kWh supporting 2.5 kW charging power and 0 to 2.5 kW discharging power offers a good cost-benefit ratio compared with for example with the stationary electric storage having a capacity of 10 kWh.

[0081] In one embodiment of the EVSE 201 the buffer battery 219 is an integral component of the EVSE. In an alternative embodiment the buffer battery is a retro fit part that is connected to the EVSE with a cable provided with a plug that is connectable with a corresponding socket arranged in a housing of the EVSE 201 . The socket and the plug are provided with touch safe contacts to avoid electrical hazards. The cable is designed for single phase or three-phase AC current and accommodates at the same time up to 8 communication lines enabling communication between the control computer 202 and the buffer battery 219. Optionally, the socket and / or the plug are designed for IP 54 degree of protection. Preferably, the EVSE 201 is configured to detect whether the buffer battery 219 is connected or not.

[0082] A power line 221 connects of the switches 212 with a regular (standardized) household power outlet 222 to which a household appliance (not shown) can be connected. Finally, the electrical installation 206 is also connected to the electrical grid via a power and data connection 223,224, respectively. Via the data connection 224 the grid operator can communicate with the control computer 202 and vice versa.

[0083] For the sake of completeness, it is noted that the buffer battery 219 is instrumental, even when the EV 213 is absent, for storing excess energy from the voltaic module 108. The stored energy can then be supplied to the home network during the night or when the production of the voltaic module 108 is insufficient to support a momentary energy consumption during the day.

[0084] The V2X set up 200 enables the internal battery 216 of the EV 213 to supply power to the electrical installation 206 and / or to the buffer battery 219. How much power is drawn from the battery of the EV 213 and how much of it is provided to the electrical installation 206, the electrical grid, the power outlet 218 and / or the buffer battery 219 is controlled by the control computer 202, which implements the method of operating the EVSE 201 according to one aspect of the present disclosure.

[0085] For many conventional V2X systems it is inefficient using the battery of an EV at low charging or discharging powers because the batteries of EVs and the EV power converter are optimized for high charging or discharging powers. Figure 3 shows a typical characteristic curve displaying charging and discharging efficiency of the power converter of an EV as a function of the charging and discharging power, wherein a negative power value corresponds to charging the battery and a positive power corresponds to discharging the battery. As can be seen from Figure 3 the efficiency of the energy transfer is highest when the battery is charged or discharged at a maximum power Pmax, e.g. Pmax=10 kW. When the absolute value of the charging and discharging power decreases the efficiency of the energy transfer goes down as well. For that reason, the manufacturers of EVs set a minimum charging and discharging lower power limit ±P2, e.g. P2=400 W or 1500 W. According to the present disclosure a method is implemented that ensures that the EV 213 can operate as a power source for replacing grid power P1 regardless of whether the consumed grid power is smaller than the lower power limit P2 of the battery 216 of the EV 213 as shown in Figure 3.

[0086] Figure 4 shows a schematic flow diagram of the method. In a first step S1 the EVSE 201 receives information regarding a lower power limit P2 of the EV 213 and receives in step S2 information representing a momentary power P1 provided from a power grid into an electrical installation 206 connected with the EVSE 201 . If the momentary power P1 is equal to or higher than the lower power limit P2 than the method proceeds in step S3 with configuring and AC / DC converter 214 of the EV 213 in accordance with the momentary power P1 . In step S4 power corresponding to the momentary power P1 is transferred to the electrical installation 206 accordance with the configuration of the AC / DC converter 214. However, if the momentary power P1 is lower than the lower power limit P2, then the AC / DC converter 214 is configured in step S5 in accordance with the lower power limit P2. In step S6 power is transferred to the electrical installation 206 in accordance with the momentary power P1 and the power difference between the momentary power P1 and the lower power limit P2 is transferred to the buffer battery 219. Alternatively, in step S6 the before mentioned power difference is transferred to an electrical appliance connected with the EVSE 201.

[0087] An alternative method sets the discharging power of the battery 216 of the EV 213 to a value that aims at maximizing the efficiency of the overall energy transfer from the EV 213 to a load which consumes the momentary power P1. To this end the EV 213 sets a supply power level P3 > P2, wherein P3 is set as high as possible by the control computer 202 which takes into account other parameters, in particular the state of charge of the battery of the EV 213. The load can be a home appliance, a home network, or even the public electricity grid. To this end, the battery 216 of the EV 213 is operated in a pulsed mode. The excess energy provided by the EV 213 and not consumed by the load is charged to the buffer battery 219. This excess energy corresponds to the difference between the supply power level P3 and the consumed momentary power P1 . As the charging level of the buffer battery 219 exceeds a predetermined upper level, the supply of power from the EV 213 is stopped. The load is supplied from that moment on with power from the buffer battery 219 until the charging level of the buffer battery falls below a predetermined lower level, and the EV 213 restarts supplying power to the load and recharges the buffer battery 219 with the before mentioned excess power. Figure 5 shows a block diagram of the control computer 202 of an electrical vehicle supply equipment (EVSE) in accordance with the first aspect of the invention, configured for implementing methods in accordance with the second to fifth aspects of the invention. In the control computer 202, one or more microprocessors 302, volatile and non-volatile memory 304, 306, and one or more communication interfaces 308 are communicatively connected via one or more signal and / or data lines or buses 312. The non-volatile memory 306 stores computer program instructions which, when executed by the one or more microprocessors 302, configure the control computer 300 to control the EVSE to execute one or more of said methods.

[0088] Individual components or functionalities of the present invention are described in the embodiment examples as software or hardware solutions. However, this does not mean that a functionality described as a software solution cannot also be implemented in hard-ware and vice versa. Similarly, mixed solutions are also conceivable for a person skilled in the art, in which components and functionalities are simultaneously partially realized in software and hardware.

[0089] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" does not exclude a plurality.

[0090] A single unit or device may perform the functions of multiple elements recited in the claims. The fact that individual functions and elements are recited in different dependent claims does not mean that a combination of those functions and elements could not advantageously be used.

[0091] List of reference signs

[0092] Mast 302 Microprocessor

[0093] Powerline 304,306 Non-volatile memory main house connection point 308 Communication interface

[0094] House 312 Data bus

[0095] Electric vehicle

[0096] Charging station

[0097] Appliance

[0098] Photovoltaic module

[0099] Electric vehicle supply equipment

[0100] Control computer a-c Communication interface a-c Power interface

[0101] Electric installation ,208 Data lines ,210 Power lines

[0102] Switches

[0103] Electric vehicle

[0104] AC / DC converter of EV

[0105] Battery of EV

[0106] AC / DC converter

[0107] Powerline

[0108] Buffer battery

[0109] Powerline

[0110] Power outlet

Claims

Claims1 . Bi-directional electrical vehicle supply equipment (EVSE) comprising a control computer (300), a first communication interface, a second communication interface, a first and a second power interface wherein the first communication interface is communicatively connected to the control computer (300) and configured for communicating with an electrical installation that is connected to the first power interface of the EVSE, wherein the second communication interface is communicatively connected to the control computer (300) configured for communicating with an electrical vehicle that is connected to the second power interface of the EVSE, wherein the EVSE further comprises one or more switches for selectively establishing and interrupting (a) the electrical connection between the EVSE and the electrical installation and the electrical vehicle, respectively, and (b) an electrical connection between the EVSE and a DC-AC-converter of a buffer battery connected to a third AC power interface, under control of the control computer (300).

2. The bi-directional EVSE of claim 1 , further comprising a fourth communication interface configured for communicating with one or more power meters associated with one or more corresponding appliances that consume electrical energy when operated.

3. The bi-directional EVSE of claim 1 or 2, wherein the apparatus is provided with a standardized household power outlet, and wherein the control computer is configured for selectively enabling or disabling a V2L mode.

4. The bi-directional EVSE of one of the preceding claims, wherein the buffer battery has a capacity of 1 to 5 kWh, preferably between 1 .5 to 3 kWh.

5. Method of operating electrical vehicle supply equipment (EVSE) in accordance with one of claims 1 to 4, the method comprising, after establishing physical connections between the EVSE and an EV: receiving information regarding a supply power level from the EV, wherein the supply power level aims at maximizing efficiency or aiming atexceeding a predetermined level of efficiency of the power transfer from the EV, receiving information representing a momentary power (P1 ) provided from a power grid into an electrical installation to which the EVSE is coupled, wherein the method further comprises, if the momentary power (P1 ) is equal to or higher than the supply power level: configuring a power converter of the EV in accordance with the momentary power (P1 ), or, if the momentary power (P1 ) is lower than the supply power level: configuring the power converter of the EV in accordance with the supply power level, transferring power to the electrical installation in accordance with the momentary power (P1 ), transferring an amount of power corresponding to the difference between the momentary power (P1 ) and the supply power level to the buffer battery connected to the third AC power interface of the EVSE, terminating the transfer of power from the EV when the buffer battery reaches or exceeds a predetermined upper charging level, supplying an amount of power corresponding to the momentary power (P1 ) from the buffer battery, and terminating the transfer of power from the buffer battery and restarting the transfer of power from the EV when the charging level of the buffer battery reaches or falls below a predetermined lower charging level.

6. Method of operating electrical vehicle supply equipment (EVSE) in accordance with one of claims 1 to 4, the method comprising, after establishing physical connections between the EVSE and an EV: receiving information regarding a lower power limit (P2) from the EV,receiving information representing a momentary power (P1 ) provided from a power grid into an electrical installation to which the EVSE is coupled, wherein the method further comprises, if the momentary power (P1 ) is equal to or higher than the lower power limit (P2): configuring a power converter of the EV in accordance with the momentary power (P1 ), and transferring power to the electrical installation in accordance with the configuration, or, if the momentary power (P1 ) is lower than the lower power limit (P2): configuring the power converter of the EV in accordance with the lower power limit, transferring power to the electrical installation in accordance with the momentary power (P1 ), and transferring an amount of power corresponding to the difference between the momentary power (P1 ) and the lower power limit (P2) to a buffer battery connected to the third AC power interface of the EVSE, or activating an appliance coupled to the electrical installation that consumes at least an amount of power corresponding to the difference between the momentary power (P1 ) and the lower power limit (P2), and- transferring power to the electrical installation in accordance with the momentary power (P1 ).

7. The method of claim 5 or 6, wherein the information representing a momentary power (P1 ) provided from a power grid into an electrical installation to which the EVSE is coupled is received or updated at intervals or continuously, and wherein configuring the power converter of the EV and the transfer of power to the electrical installation are executed in accordance with the received or updated information.

8. Method of claim 5 to 7, further comprising configuring the power converter of the EV in accordance with a supply power level aiming at maximizing efficiency or aiming at exceeding a predetermined level of efficiency of the power transfer from the EV; and transferring the amount of power from the EV corresponding to the difference between the momentary power (P1) and the supply power level to the buffer battery; terminating the transfer of power from the EV when the buffer battery reaches or exceeds a predetermined upper charging level; supplying an amount of power corresponding to the momentary power from the buffer battery; and terminating the transfer of power from the buffer battery and restarting the transfer of power from the EV when the charging level of the buffer battery reaches or falls below a predetermined lower charging level.

9. Method of operating electrical vehicle supply equipment (EVSE) in accordance with one of claims 1 to 3, the method comprising, after establishing physical connections between the EVSE and an EV: receiving information representing a momentary load on each phase of an electrical installation to which the EVSE is coupled, wherein the method further comprises, if the EV can provide electric energy only on three phases simultaneously and at equal power in each phase, and if the momentary load on the three phases in the electrical installation unequally distributed across the three phases: configuring the power converter of the EV to provide power to all three phases of the EVSE in accordance with any one of the loads on any of the phases of the electrical installation, and for each phase that has a load that is lower than the power provided from the EVSE, transferring an amount of power corresponding to the differencebetween the load on that phase and the power provided from the EV to a buffer battery connected to the third AC power interface of the EVSE, or activating an appliance coupled to the corresponding phase of the electrical installation that consumes at least an amount of power corresponding to the difference between the load on that phase and the power provided from the EV, and transferring power to the electrical installation in accordance with the configured power.

10. The method of claim 9, further comprising receiving a lower power limit (P2) from the EV, configuring the power converter of the EV in accordance with the lower power limit (P2) of the EV, and transferring any power exceeding a momentary load on a phase to the buffer battery connected to the third AC power interface of the EVSE.11 . Method of operating electrical vehicle supply equipment (EVSE) in accordance with one of claims 1 to 3, the method comprising, after establishing physical connections between the EVSE and one or more EVs: receiving information representing a momentary power (P1) provided from a power grid into an electrical installation to which the EVSE is coupled, wherein the method further comprises, if the momentary power (P1) exceeds a predetermined level: providing power corresponding to the difference between a current load on the electrical installation and the predetermined level from a buffer battery connected to the third AC power interface of the EVSE, configuring one or more EVs connected to the EVSE to enter a V2X mode, configuring the power converters of the or more EVs connected to the EVSE to provide power to the electrical installation.

12. The method of claim 11 , wherein the power converters of the one or more EVs connected to the EVSE are configured to provide a share of the total power in accordance with their respective V2X power capabilities and / or battery status.

13. The method of claim 11 or 12, wherein the power converters of the one or more EVs connected to the EVSE are configured to provide more power than the current load on the electrical installation, and wherein the difference between the current load on the electrical installation and the power provided by the one or more EVs connected to the EVSE is transferred to the buffer battery connected to the third AC power interface of the EVSE.

14. Method of operating electrical vehicle supply equipment (EVSE) in accordance with one of claims 1 to 3, the method comprising, if the EVSE is coupled to an isolated electrical network, after establishing physical connections between the EVSE and one or more EVs: detecting EVs coupled to the EVSE, selecting an EV to act as grid master, configuring the selected EV to enter a V2X mode, configuring the power converter of the selected EV to provide power to the isolated electrical network, configuring one or more further EV coupled to the EVSE to enter a V2X mode, and configuring the power converters of the one or more further EVs to provide power to the isolated electrical network.

15. The method of claim 14, further comprising selectively activating electrical loads coupled to the isolated electrical network after one or more EVs are configured to provide power to the isolated electrical network.

16. The method of claim 14 or 15, further comprising: receiving information about the maximum power capability and the available energy from the detected EVs after detection thereof.

17. The method of one or more of claims 14 to 16, further comprising : determining a load on the isolated electrical network, configuring one or more EVs to provide a respective share of the total power required for powering the load on the isolated electrical network.

18. The method of claim 17, further comprising, if an EV is newly connected to the EVSE: receiving information about the maximum power capability and the available energy from the newly connected EV, and re-running the method steps of claim 14, or, if an EV that is not the grid master is disconnected from the EVSE: re-running the method steps of claim 17.

19. The method of one or more of claims 14 to 18, further comprising if an EV that is the grid master is disconnected from the EVSE: selecting a new grid master amongst the EVs remaining coupled to the EVSE, and re-running the method steps of claim 17.

20. Control computer (202) of an electrical vehicle supply equipment (EVSE) in accordance with one of claims 1 to 3, comprising one or more microprocessors (302), volatile (304) and non-volatile (306) memory, and one or more communication interfaces (308), the aforementioned elements being communicatively connected via one or more signal and / or data lines or buses (312), wherein the non-volatile memory (306) stores computer program instructions which, when executed by the one or more microprocessors (302), configure the control computer (300) to control the EVSE to execute one or more of the methods of claims 4 to 16.21 . Computer program product comprising computer program instructions which, when executed by a microprocessor (302) of a control computer (300) of anelectrical vehicle supply equipment (EVSE) in accordance with one or more of claims 1 to 3 in an associated volatile memory (304), configure the microprocessor (302) and / or control hardware components of the EVSE to execute one or more of the methods of claims 4 to 19.

22. Computer-readable medium or data carrier retrievably storing computer program instructions representing the computer program product of claim 17.

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