DE102023113578A1 - Simultaneous charging and discharging of a drive battery of an electric vehicle - Google Patents

Abstract

A charging device (20) for a traction battery (10) contains at least two lines (L1-3) between the traction battery (10) and different phases (P1-3) of an electrical supply network, and a charging module (22) which, in a compensation mode (BK), configures one line (L1-3) as a charging line (LL) and one as a discharging line (EL) for the traction battery (10) in order to simultaneously extract electrical power (PE) from one phase (P1-3) of the supply network (4) and supply it to another phase (P1-3).
An electric vehicle (8) contains the drive battery (10) and the charging device (20).
A charger (6) for an electric vehicle (8) contains the charging device (20).
A power supply device (2) contains the charger (6), an interface (12) to the supply network (4) and a supply module (14) for an electrical end consumer (16).
When operating the charging device (20), the charging module (22) configures the lines (L1-3) as charging lines (LL) and discharging lines (EL) in order to increase the degree (G) of grid symmetry (NS).

Description

The invention relates to the charging of an electric drive battery of an electric vehicle.

From the WO 2016 / 113015 A1 The following is known: The operation of a multi-phase network, in particular a three-phase network, for example a three-phase network, is largely regulated. In particular, the power consumption of a subscriber network per phase is limited to prevent a difference in an electrical value between the phases from exceeding a maximum value. Asymmetries at the subscriber result in increased losses in the subscriber network, which must be avoided. In particular, an uneven load on the subscriber network at the phases leads to a zero point shift / star point shift. In order to compensate for this, compensating currents in the neutral conductor are necessary, which cause unnecessary losses.

From the WO 2016 / 113015 A1 It is also known that the connection of electric vehicles is increasingly being recognized as problematic. Electric vehicles place neither a temporally nor spatially deterministically predictable load on the grid. Some car manufacturers also want to charge in two phases, so that in future the permissible unbalanced load can only be on the phase not used by the vehicle. Significant unbalanced loads can arise if no intervention is made in the operation of such consumers. On the other hand, a generator, e.g. a CHP heating system, a solar system or the like, can sometimes only be operated in one or two phases. These feeds also usually lead to unbalanced loads. If, for example, a solar system feeds in on phase P1 and an electric vehicle draws electrical power on phases P2 and P3, the unbalanced load is extremely large.

The WO 2016 / 113015 A1 therefore proposes the following: Performance-optimized operation of an electrical subscriber is made possible by measuring at least one electrical quantity on at least two input-side phases of a switching matrix having at least two outputs, the inputs being connected to different phases of a subscriber network, and assigning at least one input of the switching matrix to at least one output of the switching matrix depending on the measurement, with at least fewer outputs being assigned inputs in the switching matrix than there are inputs. By switching the consumer or the generator to one or two phases of the network each, the load on the phases can also be symmetrized. Smart meters are used to measure the corresponding electrical quantities (current, voltage, power and/or phase).

The object of the present invention is to propose improvements with regard to charging an electric drive battery of an electric vehicle.

The object is achieved by a charging device according to patent claim 1. Preferred or advantageous embodiments of the invention and other categories of invention emerge from the further claims, the following description and the attached figures.

The charging device is one for an electric traction battery of an electric vehicle. In other words, the charging device enables the charging - and also the discharging, as explained below - of the traction battery in the electric vehicle, or this takes place when the charging device is operated accordingly. The charging device has at least two, in particular three, electrical lines. Each of the lines is designed to connect the traction battery of the electric vehicle - directly or indirectly for electrical power transmission - to a multi-phase electrical supply network. In particular, a traction battery that can be supplied with alternating quantities still contains an electrical direct voltage storage device and a converter in order to prepare the alternating quantities supplied to the traction battery for storage. A "direct" connection to the traction battery therefore refers to the connection to the converter, which is then an integral part of the traction battery. Such a connection is actually present during operation. The supply network has at least two, in particular three phases. Each of the lines is assigned to a different phase of the supply network. In particular, each of the three lines of the charging device is assigned to exactly one of the three phases of the supply network. When charging the electric vehicle, power from the supply network or its phases is transferred through the cables to the drive battery; when discharging, the opposite happens.

The charging device contains a charging module. This has at least one, in particular several operating modes. At least one of the operating modes is a compensation mode. Other operating modes are not explained in detail here. In the compensation mode, the charging module is set up as follows: It configures at least one of the lines as a charging line and at least one other of the lines as a discharging line in relation to the traction battery. This means: During operation, each of the charging lines can or will transport electrical power exclusively from the supply network to the traction battery on the corresponding phase of the supply network. “Exclusively” means: Power transport in counter direction is therefore not possible on the charging line. On the other hand, each of the discharge lines can and will transport electrical power from the other corresponding phase exclusively from the traction battery into the supply network - but not in the opposite direction. In compensation mode, it is therefore possible to extract electrical power for the traction battery via the charging line from the phase of the supply network assigned to the charging line and at the same time to supply electrical power from the traction battery to the other assigned phase of the supply network via the discharge line.

In compensation mode, it is therefore possible to at least partially counteract an asymmetry in the phases of the supply network that would exist without the charging device being in operation, for example by supplying power from the traction battery to a phase that is particularly loaded with power consumption, thereby reducing the load on this phase; and at the same time, electrical power is extracted from a phase that is less loaded with power consumption, which in turn increases its phase load. In this way, phase loads in the supply network are brought closer together or balanced out. Overall, the (actually existing) asymmetry in the supply network can be reduced or eliminated.

In actual compensation operation, neither of the two powers currently transported on the charging line and the discharging line is zero, otherwise the compensation effect would not occur. This affects at least one of the charging lines and at least one of the discharging lines. The power on the other lines, however, can be zero.

If the sum of the power taken from the supply network via the charging lines is greater than the sum of the power returned to the supply network via the discharging lines, the electric vehicle's drive battery is net charged, which is usually what is ultimately desired. However, it is also possible to bring about a net discharge of the vehicle battery, for example to reduce or eliminate the asymmetry in the network and thus enable an improved energy supply from the supply network elsewhere.

• In einer bevorzugten Ausführungsform ist daher das Lademodul dazu eingerichtet, die Leitungen abhängig von einem aktuellen Grad einer Netzsymmetrie des Versorgungsnetzes derart als Ladeleitung und Entladeleitung zu konfigurieren (oder auch eine bestehende Konfiguration zu ändern), dass - beim tatsächlichen Betrieb mit elektrischer Leistung auf Lade- und Entladeleitung - der Grad der Netzsymmetrie verbessert bzw. erhöht wird, also Unsymmetrien im Versorgungsnetz gemindert oder beseitigt werden.

The definition or allocation of charging lines and discharging lines to certain phases and, alternatively or additionally, the definition of the power currently transported on the lines or a maximum power on the respective line (see below) can change from time to time. The allocation can, for example, be made by simply determining or controlling in advance based on assumptions or general knowledge of the network (dis)symmetry or a degree of network symmetry. As a rule, however, it will be more sensible to design the current compensation operation depending on the degree of network symmetry that is actually present in the supply network:

• In a preferred embodiment, the charging module is therefore designed to configure the lines as charging lines and discharging lines (or to change an existing configuration) depending on a current degree of network symmetry of the supply network in such a way that - during actual operation with electrical power on the charging and discharging lines - the degree of network symmetry is improved or increased, i.e. asymmetries in the supply network are reduced or eliminated.

In a preferred embodiment, the charging device contains a limiting module. This can in particular also be part of the charging mode. The limiting module is designed to limit a power, in particular a current strength for a given mains voltage, in at least one of the lines to a maximum value. This therefore limits the maximum electrical power that is transported via the respective line from the supply network to the traction battery or in the opposite direction. In this way, overloading of the supply network or the traction battery on the phases assigned to the respective lines can be avoided.

In a preferred embodiment, the supply network is an AC network (alternating current) and the lines are AC lines, i.e. they are supplied with alternating current or alternating voltage. The charging device then contains a converter module and a DC line (direct current). The DC line leads from the converter module to the traction battery. The AC lines lead from the converter module to the supply network. In other words, the converter module is connected between the supply network and the traction battery and converts between alternating variables on the grid side and direct variables on the traction battery side. The converter module is designed to add the AC power actually flowing in the AC lines during operation to a total DC power flowing in the DC line (which can also be zero). In this way, it is possible in particular to implement the invention for phase compensation in the AC network despite a direct current or direct voltage connection of the traction battery. In compensation mode, electrical power flows in different directions on the grid side of the converter module in different phases. On the battery side of the converter module, however, the DC line either a DC power transfer to or from the traction battery or no power transfer takes place.

The object of the invention is also achieved by an electric vehicle according to claim 5. This contains the charging device according to the invention explained above and the drive battery mentioned in this context. The entire electric vehicle is thus upgraded according to the invention and can - even while its drive battery is being charged net from the supply network - carry out at least partial symmetry compensation in the supply network. The lines of the charging device can be detachably connected to the supply network. As a rule, however, only the supply network itself can recognize the degree of its network symmetry, e.g. its unbalanced load, so the electric vehicle contains in particular an interface to the supply network or to an instance correlated with it, which then communicates the unbalanced load or the asymmetry, a degree of network symmetry, etc. to the electric vehicle or its charging device.

The electric vehicle and at least some of its possible embodiments as well as the respective advantages have already been explained in connection with the charging device according to the invention.

Especially in the version with a converter module, the electric vehicle is also equipped for AC charging.

The object of the invention is also achieved by a charger according to claim 6. The charger contains the charging device according to the invention. The charger is a stationary charger and one for an electric vehicle with an electric drive battery. Such a charger is in particular a so-called "wall box" or "charging station". Thanks to the charging device according to the invention installed therein, the charger is thus enabled to carry out the symmetry compensation according to the invention in the supply network when an electric vehicle with a drive battery is connected.

The charger and at least some of its possible embodiments as well as the respective advantages have already been explained in connection with the charging device according to the invention.

Especially in the version with converter module, the charger is also equipped for DC charging of an electric vehicle.

The object of the invention is also achieved by an energy supply device according to claim 7. The energy supply device contains at least one, in particular several, chargers according to the invention. The energy supply device also contains an interface to the supply network mentioned. The charging lines are connected to the interface. In other words, the connection of the charging lines to the supply network is accomplished via the interface. The energy supply device also contains a supply module for an electrical end consumer. The "end consumer" is to be understood here as meaning that it can also contain a total of several individual consumers. The supply module is also connected to the interface via a single-phase or multi-phase power connection. In other words, both the charger and thus a drive battery connected during operation as well as the electrical end consumer connected during operation are connected to the supply network via the interface from the supply network via the supply module.

The energy supply device and at least some of its possible embodiments as well as the respective advantages have already been explained in connection with the charger according to the invention and the charging device or the electric vehicle.

Alternatively, the same effect can be achieved if the energy supply device does not contain the charging device in the form of the charger, but instead has a conventional charging connection for an electric vehicle, to which an electric vehicle according to the invention is then connected. In this case, although the charging device is strictly speaking present in the electric vehicle, it can still be attributed to the energy supply device in a certain way. A simultaneous withdrawal and supply of electrical power to different phases is also achieved in this case. In the following, however, it is assumed that the charging device in the form of the charger is "permanently" contained in the energy supply device.

Thanks to the integrated charging modules, the entire energy supply system is capable of providing very efficient phase compensation beyond the interface - depending on the number of charging modules. In particular, phase compensation is already possible internally in the energy supply system in relation to the supply modules or end consumers.

Within the energy supply system, a synergistic effect occurs between the end user and the charger with the drive battery: In the Thanks to the charger, the compensation operation improves the grid symmetry if necessary, thus enabling the end user to be operated on a more symmetrical supply grid than would be possible if it were operated "directly" on the supply grid, i.e. without the invention being implemented by means of the charger.

In particular, it is assumed that the electrical properties of the end consumer are known in the energy supply facility insofar as they affect the network symmetry/load of the individual phases. This means that, viewed from the supply network, any asymmetries that would be generated by the end consumer alone (without a charger with a connected drive battery) can be compensated for "beyond" the interface, i.e. internally in the energy supply facility. In other words, synergistic operation of end consumers and charging devices or drive batteries is possible.

In particular, the interface is the so-called "transfer point" between the supply network and the energy supply device. Thanks to the invention, such energy supply devices can therefore be operated particularly favorably in terms of network symmetry with the supply network.

In a preferred embodiment, the charging module in the charging device or in the charger is designed to take into account the current degree of network symmetry of the supply network, as explained above. This results in the effect of automatic symmetry of the supply network not only in the charging device, but in the entire energy supply device.

In a preferred embodiment, the end consumer is another charging connection for an electric vehicle - in particular not according to the invention. This can be any electric vehicle. In particular, the end consumer is not a charger according to the invention and no electric vehicle according to the invention is connected. Thus, "conventional" electric vehicles can also be advantageously charged via this "conventional" charging connection by exploiting the above-mentioned synergy effects in the energy supply device with a drive battery according to the invention via the chargers according to the invention. Other electrical consumers can also be provided as end consumers alternatively or additionally, such as stationary energy storage devices or heat pumps.

In particular, the energy supply facility is or contains a charging park for electric vehicles.

The object of the invention is also achieved by a method according to patent claim 10. This serves or is designed to operate a charging device according to the invention, in particular in the embodiment in which the degree of network symmetry of the supply network is taken into account in the charging module.

In a preferred embodiment, the current degree of network symmetry of the supply network is first determined, as explained above in an embodiment of the charging device. In any case, the charging module then configures the lines - in particular depending on the current degree determined - as charging lines and discharging lines in such a way that the degree of network symmetry of the supply network can be increased or the network symmetry can be improved through actual operation, i.e. the flow of electrical power through the charging line and discharging line. "Can be" is to be understood here as meaning that - unless the network symmetry changes fundamentally and unexpectedly - taking into account the currently determined state / degree of network symmetry when choosing the charging and discharging lines for the relevant phases, the network symmetry actually improves, i.e. the degree is increased (if the maximum value / absolute symmetry has not already been reached). In the latter case, the optimal degree is at least maintained.

The invention is based on the following findings, observations and considerations and also has the following preferred embodiments. These embodiments are sometimes referred to as "the invention" for the sake of simplicity. The embodiments can also contain parts or combinations of the above-mentioned embodiments or correspond to them and/or possibly also include embodiments not previously mentioned.

According to the invention, a phase-selective charging and discharging control results for optimizing the charging/discharging performance.

The invention is based on the observation that, for example, in Germany, Austria and other countries, there are requirements for maintaining symmetry in multi-phase grid connections (supply network) (e.g. regulated in VDE AR 4100). Currently, when charging an electric vehicle's drive battery with AC, this can only be done by controlling all three grid phases (e.g. all phases at at least 6A or off) due to the standards (IEC 61851-1, ISO 15118-2). ISO 15118-20 provides It is now possible to set the charging current phase-selectively (P1 6A, P2 10A, P3 16A) depending on the current power level of the network.

Currently, due to the standards (IEC 61851-1, ISO 15118-2), grid symmetry when charging electric vehicles (EVs) with AC can only be achieved by controlling all three grid phases (all phases at least 6A or off). ISO 15118-20 now offers the option of setting the charging current on a phase-selective basis (P1 6A, P2 10A, P3 16A) depending on the current power level of the grid. ISO 15118-20 also offers the option of discharging EVs or their drive batteries for the first time in addition to charging.

The invention is therefore based on the consideration that the following procedure must currently be followed: If, for example, many consumers are already loading the network on phase P1, the charging current or the resulting charging power of the EV on phases P2 and P3 must also be limited when charging a drive battery, since phases P1 to P3 can only be controlled simultaneously with regard to their maximum charging current.

The invention is based on the following idea: If, for example, many consumers are already loading the grid on phase P1, the charging current or the resulting charging power of the EV on phases P2 and P3 no longer needs to be limited or only partially limited when discharging is taking place on phase P1 at the same time. This makes it easier to comply with local/national guidelines regarding grid symmetry or, in the case of a double charging point, in addition to the drive battery charged according to the invention at the first charging point, an EV can be charged with more charging power at the second charging point (not according to the invention) without phase-selective charging optimization (synergy effect between the two charging points). This phase-selective control according to the invention at the first charging point can be used not only for AC bidirectional EVs with the inventive OBC (onboard charger, charging device/charging module) but also at a DC bidirectional charging station (inventive charger with converter) that converts the multi-phase AC grid into DC voltage for the EV.

According to the invention, there is, for example, added value especially for charging park operators (energy supply device according to the invention) who want to specifically charge vehicles and who would otherwise, i.e. without the invention, have problems at the grid connection point (interface) due to the local / national symmetry requirements of the supply grid.

• Betrachtet wird als Beispiel ein dreiphasiger Netzanschluss mit je 16A zulässiger Entnahmeleistung pro Phase. An dem Netzanschluss sind zwei Ladesäulen für Elektrofahrzeuge parallel verschaltet. Weitere Verbraucher sind vorhanden. Die erste Ladesäule ist erfindungsgemäß zu einer phasenselektiven bidirektionale Optimierung (Laden und Entladen gleichzeitig auf verschiedenen Phasen) ausgerüstet, die zweite nicht.

The following scenarios are possible thanks to the invention:

• As an example, a three-phase grid connection with a permissible power draw of 16A per phase is considered. Two charging stations for electric vehicles are connected in parallel to the grid connection. Other consumers are present. According to the invention, the first charging station is equipped for phase-selective bidirectional optimization (charging and discharging simultaneously on different phases), the second is not.

Scenario 1:

The mains connection is already loaded with 11 A by other consumers on phase P1 (not explained in detail here), therefore the following charging capacities are available for both charging stations: P1: 5A, P2: 16A, P3: 16A.

A conventional EV is to be charged in the conventional way at the second charging station, i.e. its charging power must be set to at least 6A on all 3 phases; charging below this is not possible. Since only 5 A are available on phase P1, charging the EV is not possible at all.

Thanks to the invention, however, the corresponding line can now be configured as a discharge line on phase P1 at the first charging station and 1A can be fed back into the supply network from a connected drive battery on phase P1. This means that P1: 6A, P2: 16A, P3: 16A are again available for the second charging station. An EV can now be charged here with P1: 6A, P2: 6A, P3: 6A. This leaves P2: 10A and P3: 10A charging power at the first charging station. The two lines on phases P2 and P3 are then configured as charging lines. The drive battery at the first charging station can therefore be discharged with 1A on phase P1 and charged with a total of 20A on phases P2 and P3, which results in a net charging current of 19A for the drive battery. Thanks to the invention, it is therefore possible to charge both EVs in parallel at both charging stations.

Scenario 2:

The mains connection is already loaded with 11 A by additional consumers on phase P1 and phase P2, and with 6 A on phase P3, so the following charging capacities are available for both charging stations: P1: 5A, P2: 5A, P3: 10A.

At the second charging station, a conventional EV is to be charged conventionally, ie its charging power must be set to at least 6A on all 3 phases, below which charging is not possible. Since only 5 A are available on phases P1 and P2, charging the EV is not possible at all.

Thanks to the invention, however, the corresponding line can now be switched to phases P1 and P2 on the first charging station as a discharge line and 1A can be fed back into the supply network from a connected drive battery on phase P1 and phase P2. This means that P1: 6A, P2: 6A, P3: 10A are again available for the second charging station. An EV can now be charged here with P1: 6A, P2: 6A, P3: 6A. This leaves P3: 4A of charging power at the first charging station. The drive battery at the first charging station can therefore be discharged with 1A on phases P1 and P2 and charged with a total of 4A on phase P3, which results in a net charging current of 2A for the drive battery. Thanks to the invention, it is therefore possible to charge both EVs in parallel at both charging stations.

Scenario 3:

The mains connection is already loaded with 16 A by additional consumers on phase P1 and phase P2, but not on phase P3, so the following charging capacities are available for both charging stations: P1: 0A, P2: 0A, P3: 16A.

A conventional EV is to be charged in the conventional way at the second charging station, i.e. its charging power must be set to at least 6A on all 3 phases; charging below this is not possible. Since only 0A is available on phases P1 and P2, charging the EV is not possible at all.

Thanks to the invention, however, the corresponding line can now be switched to phases P1 and P2 at the first charging station as a discharge line and 6A can be fed back into the supply network from a connected drive battery on phase P1 and phase P2. This means that P1: 6A, P2: 6A, P3: 16A are again available for the second charging station. An EV can now be charged here with P1: 6A, P2: 6A, P3: 6A. This leaves P3: 10A charging power at the first charging station. The drive battery at the first charging station can therefore be discharged with 6A on phases P1 and P2 and charged with a total of 10A on phase P3, which results in a net discharge current of 2A for the drive battery. Thanks to the invention, it is therefore possible to charge the second EV, with the drive battery being discharged at the first charging station with a net 2A.

Alternatively, in this scenario 3, the corresponding line can also be switched to phases P1 and P2 at the first charging station as a discharge line and 16A each can be fed back into the supply network from a connected drive battery on phase P1 and phase P2. This means that P1: 16A, P2: 16A, P3: 16A are again available for the second charging station. An EV can now be charged with P1: 16A, P2: 16A, P3: 16A. This means that there is no charging power left at the first charging station. The drive battery at the first charging station is therefore operated with a net discharge current of 32A for the drive battery. Thanks to the invention, however, maximum charging of the second EV is possible, with the drive battery at the first charging station being discharged with a net of 32A. This means that both EVs are “recharged” in a way, for example to make the EV at the second charging station ready for use.

• 1 eine Energieversorgungseinrichtung mit Ladegerät und ein Elektrofahrzeug und einen Endverbraucher,
• 2 die Ladeeinrichtung aus 1 mit Elektrofahrzeug im Detail und in alternativen Einbindungen in das Elektrofahrzeug oder das Ladegerät aus 1.

Further features, effects and advantages of the invention emerge from the following description of a preferred embodiment of the invention and the attached figures. Each of these shows a schematic principle sketch:

• 1 an energy supply device with charger and an electric vehicle and an end user,
• 2 the charging device 1 with electric vehicle in detail and in alternative integrations into the electric vehicle or the charger 1 .

1 shows an energy supply device 2 in the form of a charging park for electric vehicles, which is connected to an electrical supply network 4, here a national power grid or distribution network. The energy supply device 2 contains a charger 6, here a charging station, for an electric vehicle 8, which in turn contains an electric drive battery 10. The supply network is a three-phase AC network with three phases P1-3.

The energy supply device 2 also contains an interface 12 to the supply network 4. The charger 6 contains three charging lines L1 to L3. These are connected to the interface 12, each one to one of the phases P1-3. Thus, each of the lines L1-3 is assigned to exactly one of the phases P1-3, here, for example, the line L1 to the phase P1, the line L2 to the phase P2 and the line L3 to the phase P3. The supply network 4 is a three-phase 230V three-phase current or three-voltage network.

The energy supply device 2 also contains a supply module 14, which is designed here as a conventional charging station for another electric vehicle, not explained in more detail. The other electric vehicle is an example of an electrical end consumer 16, which is supplied with electrical power by the supply module 14. Instead of or in addition to the electric vehicle, this could also be other electrical end consumers. cher, e.g. a stationary electrical energy storage device, a heat pump, etc. The supply module 14 is electrically connected or supplied to the interface 12 via a power connection 18, here also a three-phase connection cable. The end consumer 16 is therefore a charging connection for the electric vehicle in the form of the end consumer 16.

The energy supply device 2 contains further chargers corresponding to the charger 6 and supply modules corresponding to the supply module 14, all of which are also connected in the same way to the interface 12, but are not shown further here for reasons of clarity.

The charger 6 is therefore a charger for the electric vehicle 8 with the electric drive battery. The charger 6 contains a charging device 20 for the drive battery 10 of the electric vehicle 8. The charging device 20 contains the three lines L1 to L3. Each of the lines L1 to L3 is designed to connect the drive battery 10 of the electric vehicle 8 to the multi-phase electrical supply network 4, here indirectly via further connection lines that are not specified in more detail.

The charging device 20 contains a charging module 22. The charging module 22 has various (symbolically shown) operating modes 24, here a normal operation BN and a compensation operation BK.

Normal operation BN is used to charge the traction battery 10 from the supply network 4 simultaneously via all three lines L1 to L3, which then all represent charging lines LL. Normal operation BN is not relevant here and is therefore not explained further.

In the compensation mode BK, the charging module 22 is set up to configure at least one of the lines L1 to L3, here the line L1, as a discharge line EL (symbolically indicated here by a directional arrow) for the traction battery 10 and at the same time to configure at least one other of the lines L1-3, here the lines L2 and L3, as a charging line LL for the traction battery 10. This configuration means that it is only possible to transport electrical power PE from the supply network 4 to the traction battery 10 via the charging lines LL, but not in the opposite direction. It is only possible to transport electrical power EL from the traction battery 10 to the supply network 4 via the discharge line EL, but not in the opposite direction. In the compensation mode BK, the transported power PE is not zero for at least one of the discharge lines EL and at least one of the charging lines LL. Thus, there is simultaneous energy transport via the discharge line EL into the supply network 4 and via the charging line LL from the supply network 4.

In this configuration, it is therefore possible, or is actually achieved when the compensation operation BK is carried out, that the corresponding power flow takes place. The respective transport direction of the electrical power PE is indicated by arrows in the 1 indicated. By transporting the power PE in different directions with respect to the supply network 4, its current degree G of its network symmetry NS is changed with respect to the phases P1-P3.

The charging module 22 is informed about this current degree G of the network symmetry NS and configures the lines L1 to 3 according to this degree G as discharge lines EL and charging lines LL in order to increase the degree G of the network symmetry NS with regard to the phases P1-3 by transporting the electrical power PE on these lines, i.e. to at least better or completely symmetrize the supply network 4.

2 shows the charging device 22 and its connection to the supply network 4 again symbolically in an enlarged view, omitting the rest of the energy supply device 2, in particular the interface 12. The charging device 20 also contains a limiting module 26. This is designed to limit the electrical power PE in each of the three lines L1 to L3 to a respective maximum value PMAX1-3. Therefore, only power PE up to the maximum value PMAX1-3 can flow through the lines L1-3. This prevents overloading of both the supply network 4 and the drive battery 10 (power extraction/feed-in).

In the present example, the supply network 4 is an AC network, i.e. it has phases P1 to P3 as alternating voltages or alternating currents. The lines L1 to L3 are therefore AC lines 30. As in the 1 and 2 shown, the corresponding AC supply can be provided via AC lines 30 in three phases to the traction battery 10, in other words the electric vehicle 8 can be charged via an AC connection up to three phases. In an alternative embodiment shown in dashed lines, the charging device 20 contains a converter module 28. The AC lines 30 then lead from the supply network 4 only to the converter module 28. The charging device 20 then also contains a DC line 32, which leads indirectly from the converter module 28 to the traction battery 10. The electric vehicle 8 or the traction battery 10 is in this case supplied with direct current or direct voltage or direct power, whereby a power flow is always possible in both directions. A total DC power DCS is exchanged between the traction battery 10 and the converter module 28 via the DC line 32. The AC powers ACL1-3 (positive and negative components, depending on the transport direction) flowing via the lines L1 to L3 are added to the total DC power DCS in the converter module 28.

2 shows, here in dash-dotted lines, that the charging device 20 as in 1 is contained in the charger 6, which is available for charging the electric vehicle 8 which is separate from it. The electric vehicles 8 therefore do not need to be specially equipped to implement the phase compensation in the supply network 4, they only need to support a power transport of the power PE in both directions (from the supply network 4 to the traction battery 10 or vice versa), and possibly also a net discharge of the traction battery 10.

2 also shows an alternative possibility in dashed lines, namely that the charging device 20 is not part of the charger 6, but is part of the electric vehicle 8 alongside the drive battery 10. The charging device 20 is therefore a specific charging device only for this drive battery 10 in this electric vehicle 8. This in turn results in the effect that, thanks to the electric vehicle 8 equipped in this way, phase compensation in the supply network 4 is possible via any charging station, provided that this also allows power transport in both directions as described above. Knowledge of the network symmetry by the electric vehicle 8 is assumed here, e.g. through suitable information transmission from the supply network 4 to the electric vehicle 8.

In all embodiments according to the 1 and 2 the charging device 20 is operated according to the following procedure: In compensation mode BK, the charging module 22 configures the lines L1 to L3 as charging lines LL and discharging lines EL in such a way that the degree G of the network symmetry NS can be increased and is actually increased when the compensation mode BK is actually carried out, i.e. when power PE is actually exchanged bidirectionally with the various phases P1-3 of the supply network 4. This configuration can be based on prior knowledge, assumptions, etc.

Preferably, the current degree G of the network symmetry NS of the supply network 4 is also determined before the (selection of the specific) configuration. The charging module 22 then configures the lines L1 to L3 depending on the current degree G.

list of reference symbols

2

energy supply facility

4

supply network

6

charger

8

electric vehicle

10

drive battery

12

interface

14

supply module

16

end consumer

18

power connection

20

charging device

22

charging module

24

operating modes

26

limiting module

28

converter module

30

AC line

32

DC line

L1-3

lines

P1-3

phase

BN

normal operation

BK

compensation operation

EL

discharge line

LL

charging cable

PE

Performance

G

degree (current, network symmetry)

NS

network symmetry

PMAX1-3

maximum value

DCS

DC total power

ACL1-3

AC power

QUOTES INCLUDED IN THE DESCRIPTION

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

Cited patent literature

• WO 2016 / 113015 A1 [0002, 0003, 0004]

Claims (11)

Charging device (20) for an electric traction battery (10) of an electric vehicle (8), - with at least two lines (L1-3), each of the lines (L1-3) being designed to connect the traction battery (10) of the electric vehicle (8) to an electrical supply network (4) having several phases (P1-3), - and each of the lines (L1-3) is assigned to a different phase (P1-3) of the supply network (4), - with a charging module (22) which has at least one operating mode (24) in the form of a compensation mode (BK), in which it is designed to - configure at least one of the lines (L1-3) as a charging line (LL) and at least one other of the lines (L1-3) as a discharging line (EL) for the traction battery (10) in order to enable: - electrical power to be supplied via the charging line (LL) of the assigned phase (P1-3) of the supply network (4). (PE) for the traction battery (10) exclusively, - and at the same time to supply electrical power (PE) from the traction battery (10) exclusively via the discharge line (EL) of the assigned phase (P1-3) of the supply network (4). Charging device (20) after claim 1 , characterized in that the charging module (22) is designed to configure the lines (L1-3) as a charging line (LL) and a discharging line (EL) depending on a current degree (G) of a network symmetry (NS) of the supply network (4) in such a way that the degree (G) is improved during actual operation with electrical power (PE). Charging device (20) according to one of the preceding claims, characterized in that the charging device (20) contains a limiting module (26) which is designed to limit the electrical power (PE) in at least one of the lines (L1-3) to a maximum value (PMAX1-3). Charging device (20) according to one of the preceding claims, characterized in that - the supply network (4) is an AC network and the lines (L1-3) are AC lines (30), - with a converter module (28) and a DC line (32) which leads from the converter module (28) to the traction battery (10), - wherein AC lines (30) lead from the converter module (28) to the supply network (4), - wherein the converter module (28) is designed to add the AC powers (ACL1-3) flowing in the AC lines (30) to a total DC power (DCS) flowing in the DC line (32). Electric vehicle (8), - with an electric drive battery (10), - with a charging device (20) according to one of the Claims 1 until 4 for the drive battery (10), wherein the lines (L1-3) of the charging device (20) can be detachably connected to the supply network (4). Charger (6) for an electric vehicle (8) with an electric drive battery (10), with a charging device (20) according to one of the Claims 1 until 4 , wherein the lines (L1-3) of the charging device (20) are permanently connected to the supply network (4). Energy supply device (2) - with at least one charger (6) according to claim 6 , - with an interface (12) to the supply network (4), wherein the charging lines (L1-3) are connected to the interface (12), - with a supply module (14) for an electrical end consumer (16), which is also connected to the interface (12) via a power connection (18). Energy supply facility (2) according to claim 7 , characterized in that at least one of the charging devices (6) comprises a charging device (20) with a charging module (22) according to claim 2 contains. Energy supply device (2) according to one of the Claims 7 until 8 , characterized in that the end consumer (16) is a charging connection for an electric vehicle (8). Method for operating a charging device (20) according to one of the Claims 1 until 4 , in which: the charging module (22) configures the lines (L1-3) as charging line (LL) and discharging line (EL) such that a degree (G) of a network symmetry (NS) of the supply network (4) can be increased. procedure according to claim 10 , in which - a charging device according to one of the Claims 2 until 4 is operated, - a current degree (G) of the network symmetry (NS) is determined, - the charging module (22) configures the lines (L1-3) as a charging line (LL) and a discharging line (EL) depending on a current degree (G) in such a way that the degree (G) can be increased during actual operation with electrical power (PE).

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