DE102018203198A1 - Method for charging an electrically driven or drivable motor vehicle and charging station - Google Patents

Abstract

The invention relates to a method for charging an electrically driven or drivable motor vehicle (4), in which the motor vehicle (4) is connected to a charging point (10) of a charging station (2) fed from a single or multi - phase supply network (8) a charging process, in which the motor vehicle (4) is charged with a charge current (IL) taken from the charging point (10) monitors a network parameter, in particular the mains voltage (UN) and / or the network frequency (fN) of the supply network (8) is set, and wherein the charging current (IL) on the basis of the network parameter (UN, fN) is set.

Description

The invention relates to a method for charging an electrically driven or drivable motor vehicle, in particular an electric or hybrid vehicle, in which the motor vehicle is connected to a charging point of a fed from a single- or multi-phase supply network charging station. The invention further relates to a charging station for charging an electrically driven or abortable motor vehicle, in particular for carrying out the method.

Electrically driven or drivable motor vehicles, such as electric or hybrid vehicles, usually have an electric motor as a drive. The electric motor is in this case fed by means of an electrochemical energy storage of a vehicle electrical system of the motor vehicle with electrical energy. A "charging of an electrically or electrically driven or drivable motor vehicle" is understood here and below to mean, in particular, the charging (charging) of such an energy store with electrical energy.

To improve the practicality of electric or electric motor driven or driven vehicles, it is desirable that the vehicle-internal energy storage of the electrical system can be charged at any time as quickly and easily. For this purpose, specially adapted charging stations or charging stations, so-called charging stations, have been developed.

Such charging stations usually have a charging point for connecting a motor vehicle to be charged, which is guided by means of a network connection to a supply network. The supply network is often a public power supply, the charging point is usually operated at a low voltage level of about 230 V (volts).

In the course of the traffic change, both the number of charging stations and the number of electrically driven or driven vehicles is steadily increasing. Due to the increasing number of charging stations, the network load of the supply network is also increasing. There is a risk here that several simultaneous or parallel charging processes of motor vehicles can cause the supply network to collapse. The charging stations are often filled with integrated charge controllers for load management, by means of which the extracted power of each connected motor vehicle is controlled. Disadvantageously, in this case the load of the supply network is not taken into account, so that a permanent and reliable operation of the charging stations can not be ensured.

The invention has for its object to provide a particularly suitable method for charging an electrically driven motor vehicle. In particular, a power supply feeding network should not be overloaded even with a simultaneous or parallel charging of multiple vehicles. The invention is further based on the object of specifying a charging station for carrying out the method.

With regard to the method, the object with the features of claim 1 and with respect to the charging station with the features of claim 8 is achieved according to the invention. Advantageous embodiments and further developments are the subject of the respective subclaims.

The method according to the invention is suitable and designed for charging an electrically driven or drivable motor vehicle, in particular an electric or hybrid vehicle. The motor vehicle is in this case connected to a charging point of a charging station fed from a single- or multi-phase supply network. A supply network or power network is to be understood here and below in particular a network of electrical power lines and associated facilities such as power, switching and substations. Under a supply network are here and below also so-called island grids, ie power grids, which consist of only one or a few power generators and / or energy storage, and provide a spatially or locally limited area and have no connection to other power or supply networks to understand , Such an isolated grid can be implemented, for example, as a photovoltaic system (PV system) and / or as a generator, in particular as a fuel generator. The conjunction "and / or" is to be understood here and below in such a way that the features linked by means of this conjunction can be designed both together and alternatives to one another.

According to the method it is provided that during a charging process in which the motor vehicle is charged with a charge current drawn from the charging point, at least one network parameter of the supply network is monitored.

A network parameter here and below means, in particular, a parameter, that is to say a characterizing physical variable, of the electrical supply network, for example the mains voltage and / or the network frequency.

The term "mains voltage" here and below refers in particular to the amplitude, that is to say the voltage value, of the electrical voltage of the supply network.

The term "mains frequency" here and below refers in particular to the frequency of the electrical energy supply by means of alternating voltage in the supply network.

In one conceivable embodiment, the mains voltage is detected as a network parameter, for example, with a voltage detection device (voltage measuring device) continuously, ie continuously or essentially without interruption, or periodically, ie at regular time intervals. In this case, it is possible for the or each network parameter to be detected or measured within or in the area of the charging station. It is likewise conceivable that the network parameter is monitored externally, that is to say at a network point or network connection point of the supply network remote from the charging station, and communicated, for example, to the charging station. The monitoring of the network parameter according to the invention in this case is preferably carried out separately or separately from the actual charging process, that is, the supply of electrical energy into the motor vehicle. In other words, the network parameter is additionally monitored next to the charging process.

The charging current is set based on the detected network parameter. In particular, the charging current is hereby preferably controlled and / or regulated on the basis of the mains voltage and / or the mains frequency. By monitoring the network parameter of the supply network, the current network situation of the supply network is considered during the charging process of the motor vehicle. As a result, a particularly suitable method for charging a motor vehicle is realized.

In a conceivable embodiment, a power is calculated based on the detected voltage value of the mains voltage, which may relate to the motor vehicle from the charging point. Based on this power value, the charging current is set.

The inventive method ensures that the power or grid is not overloaded in the course of a charging process of the motor vehicle. According to the invention, the load itself, but the load, is not evaluated with respect to the network situation prevailing at the respective time, in particular with regard to a locality between an energy producer of the supply network and the consumer or the charging station, for the determination of the charging current ,

The mains voltage as network parameter is in particular a measure of the local grid stability. A "stability of the supply network" or "grid stability" is understood here and below to mean in particular the supply quality of the supply voltage of the supply network, ie the voltage quality or voltage fluctuation with respect to the normal voltage and the stability of the network frequency. Correspondingly, a "(network) stabilization" is understood to mean in particular a measure which is conducive to the stability or network stability of the supply network.

The mains frequency and its deviation from a nominal value is a direct quality indicator for the voltage stability of the supply network. In particular, an oversupply of electrical power leads to an increase in the network frequency, and in the case of a sub-supply, accordingly to a reduction. The grid frequency is thus in particular an indicator of the global or general availability of electrical energy in the supply network.

The voltage value of the mains voltage, as a measure of the local grid stability, and the grid frequency, as a measure of the global grid stability, are preferably monitored as network parameters. In monitoring the network frequency, in particular a frequency change, ie a change in the frequency value over time, is monitored. For example, the charging power or the charging current is reduced at a negative frequency change and increased accordingly at a positive frequency change.

In an advantageous development, the network parameter is compared with a first and a second stored threshold range. In particular, the threshold ranges limit a desired or predetermined desired value (range) for the charging current or for the charging power. The charging current is thereby reduced or reduced when the mains voltage reaches or exceeds the first threshold range, or when the network parameter reaches or falls below the second threshold range.

In one possible form of further development, the network voltage is compared as a network parameter with the first and the second stored threshold range as voltage limits. The charging current is thereby reduced or reduced when the mains voltage reaches or exceeds the first threshold range, or when the network parameter reaches or falls below the second threshold range. In other words, the charging current between the voltage limits of the threshold ranges is set to a maximum possible or permissible current value, wherein, when one of the voltage limits is reached, the current value for stabilizing the mains voltage is reduced. This means that, if the mains voltage of the supply network is too low, the charging capacity of the charging station is reduced to an acceptable level, and that the charging power is increased when the mains voltage rises again.

The first and second threshold ranges may each have a single threshold value or even a number of staggered, ie consecutive, threshold values. In particular, in the case of a further development form having a plurality of staggered threshold values per threshold value range, the charging current is set successively or cascading in the course of exceeding or falling below the threshold value range.

In a further development form, in which the mains voltage is monitored as a network parameter, the first and second threshold ranges are preferably chosen based on the normal voltage of the supply network. In other words, the threshold ranges limit a setpoint range around the normal voltage. The threshold ranges thus define a voltage band in which the charging is performed. If, for example, the supply network has a normal voltage, ie an ordinary mains voltage or nominal voltage, of 230 V (volts), the first and second threshold ranges are defined, for example, as a ± 10% deviation from this normal voltage.

For example, the first threshold range has a single threshold equal to 253V. Preferably, the second threshold range is implemented with two thresholds, wherein the first threshold value is 218 V, for example, and the second threshold value is 207 V. This means that the charging current is about 218 V is substantially constant, and is set in a range between 218 V to 207 V to a reduced current value. The charging current or the charging power is preferably regulated to zero or at least a predefinable or stored minimum value when the mains voltage reaches or falls below the second threshold value of 207 V. A setting or regulation of the charging current or the charging power to zero corresponds to an interruption or termination of the charging process.

The threshold values of the threshold ranges are defined, for example, by means of a linear function or a ramp. This means that the regulation and / or adjustment according to the mains voltage can be implemented simply and with little effort by means of a linear definition.

In a suitable further development form, the power is reduced when reaching or falling below the second threshold range, ie the lower voltage limit, linearly, in particular as a percentage. For example, the second threshold range has two threshold values as absolute range limits. The first threshold value of the second threshold range is suitably set at -5% of the normal voltage and the second threshold value of the second threshold range is dimensioned at approximately -10%. Thus, up to -5% of the normal voltage is still controlled with 100% of the charging power or the charging current. At -7.5%, for example, only 50% of the charging power and from - 10% with 0% of the charging power is controlled.

Preferably, the charging station in this case includes a correction value, which reflects a distance of the charging station to the next transformer (mains transformer of the supply network). This will prevent charging stations from charging less efficiently at weaker grid points (grid connection points) than at strong grid points.

In a suitable embodiment of the method, it is provided that upon reaching or falling below the second threshold range, a reactive power is fed from the motor vehicle into the grid for grid stabilization. The reactive power component of the supply network and the motor vehicle as a current consumer is set in particular by the cosine Phi value (cos-φ) in the vector diagram of current and voltage. The second threshold range thus defines a limit value for the reactive power reference of the motor vehicle. The second Schwellschwertbereich thus requires the stabilization of the supply network in order to avoid an undervoltage, which can lead to a failure of the charging station and / or the motor vehicle.

According to the method is thus provided that the charging station pretends the motor vehicle a reactive power reference. This means that the electric car receives a charging current, wherein the mains voltage is at least partially lowered, and wherein the motor vehicle, a reactive power is fed to the network voltage again - at least slightly - increase (increase). This stabilizes the mains voltage.

In one conceivable embodiment, the first threshold range and / or the second threshold range are determined on the basis of the monitored network parameter, for example based on a measured mains voltage and / or a measured mains frequency. In an expedient embodiment, the first threshold range and / or the second threshold range are set on the basis of network stability, in particular based on a network stability factor, of the supply network. Due to the development, it is possible that the network parameters, in particular the mains voltage, is operated stably within defined limits.

The supply network is limited by the locally available amount of electricity. If locally too many charging stations simultaneously or in parallel draw current from the supply network, then the network parameter, in particular the mains voltage, drops locally below the limits of the threshold ranges. This reduces the network stability. By setting the threshold ranges on the basis of the detected network parameter, it is thus possible for the charging power to be adapted independently or automatically to the network conditions and especially to the network voltage. As a result, a local overload of the network is avoided, whereby the voltage band is reliably maintained.

For example, the upper limit of the second threshold range is set to -4% of the normal voltage for a strong, ie (voltage) stable, network point, and set to -6% of the normal voltage for a weak, ie (voltage-) unstable network point. The threshold ranges, for example, manually, after removal of a transformer, Georeferenziell or be predetermined by the network operator.

Preferably, the network stability factor, that is, a measure of how stable the grid reacts to the charging process, taken into account and included in the regulation and / or adjustment of the charging current. The network stability factor is taken into account, for example, at the regulation or setting speed of the charging current. This makes it possible to regulate faster with a weak supply network than with a strong supply network.

In an advantageous embodiment, the supply network is designed as a multi-phase three-phase or AC network with a number of (network) phases, wherein the network parameters for each phase is monitored individually. As a result, a particularly reliable monitoring of the network parameters and, as a consequence, a particularly effective charging process of the motor vehicle is made possible.

An additional or further aspect of the invention provides in this case that the charging point is guided phase-selectively switchable to each one of the phases of the supply network. In other words, the charging point is led to all phases of the supply network, in each case only one phase is used for powering or charging the motor vehicle, and wherein it can be switched between the phases. According to the method, it is provided here that switching from a first phase to one of the other phases is achieved when the monitored network parameter of the first phase reaches or falls below a threshold value. In other words, a phase-dependent or phase-selective switching is thus realized. This allows the most uniform possible load or utilization of all (network) phases of the supply network, whereby the network stability is improved.

In a preferred embodiment, the charging current or the charging power is reduced at a connection of another motor vehicle at another charging point of the charging station. In other words, the charging power or the charging current at the beginning of a charging process is comparatively high, and is lowered at a connection of another motor vehicle. As a result, the newly connected motor vehicle allows a greater charging power. In other words, new charging at the charging station is preferred. This ensures on the one hand that the maximum permissible load current of the charging station is not exceeded. On the other hand, therefore, an urgency of charging is considered, and thus it tends to be preferred vehicles with a depleted (discharged) energy storage. As a result, essentially a time-variable or dynamic charging power or charging current is realized.

In this case, it is conceivable, for example, that the threshold values or threshold ranges are adapted as the time progresses, so that a more sensitive regulation or adjustment to the network state of the supply network is made possible.

It is also conceivable that in addition to network parameters of the supply network other parameters such as the internal temperature of the charging station, the temperature of a charging cable or the like. be taken into account for the regulation and / or adjustment of the charging power or the charging current. For example, the charging current is increased at low ambient and charging station temperatures until the cable temperature of the charging cable increases. Subsequently, the charging current is reduced.

In an alternative embodiment, it is conceivable, for example, that the state of charge of the energy store of the connected motor vehicles is detected, and that the charging currents are set with regard to the respective state of charge.

The charging station according to the invention is suitable for charging an electrically driven or drivable motor vehicle and set up. The charging station has at least one charging point fed from a single- or multi-phase supply network for connection of the motor vehicle. The charging station furthermore has a controller, that is to say a control unit, for example as part of a charge controller.

The controller of the charging station is generally program and / or circuitry for Implementation of the method described above for charging a connected motor vehicle suitable and furnished. The controller is thus concretely configured to determine a network parameter when the charging cable is connected to the charging point, and to set the charging current with which the energy store of the motor vehicle is charged in the course of a charging process on the basis of this. Alternatively, it is also conceivable that the network parameter is determined externally, ie at a distance, from the charging station or measured and then communicated to the controller for monitoring.

In a preferred embodiment, the controller is formed at least in the core by a microcontroller with a processor and a data memory in which the functionality for implementing the method according to the invention in the form of operating software (firmware) is implemented by programming, so that the process - optionally in interaction with a Motor vehicle or cable user - is performed automatically when running the operating software in the microcontroller.

Alternatively, the controller may be provided by a non-programmable electronic component, e.g. an application specific circuit (ASIC), in which the functionality for implementing the method is implemented by means of circuitry.

By the method according to the invention, a particularly grid-friendly charging station is realized, which contributes to the voltage stabilization of the power or supply network during a charging process.

• 1 eine Ladestation zum Laden eines elektrisch angetriebenen oder antreibbaren Kraftfahrzeugs, und
• 2 ein Versorgungsspannungs-Ladestrom-Diagramm.

Hereinafter, an embodiment of the invention is explained in detail with reference to a drawing. Show:

• 1 a charging station for charging an electrically driven or drivable motor vehicle, and
• 2 a supply voltage charging current diagram.

Corresponding parts and sizes are always provided with the same reference numerals in all figures.

The 1 shows a schematic and simplified representation of a charging station or charging station 2 as a supply device or charging station for charging an electrically driven or driven motor vehicle, in particular an electric vehicle 4 , The charging station 2 is by means of a network connection or network point (network connection point) 6 to a three-phase three-phase network as a supply network 8th connected.

The supply network 8th Here is in particular a three-phase 230 V AC power grid, with a phase on the grid point 6 to a charging point 10 the charging station 6 is guided. To the charging point, for example as a socket 10 is the motor vehicle 4 is by means of an electric charging cable 12 connected.

The charging cable 12 has a first connector 14 to the plug connection with the charging point 10 and a second, vehicle-side connector 16 to the connector with a charging interface eighteen of the motor vehicle 4 on. Via the charging interface eighteen is an in-vehicle energy storage 20 of the motor vehicle 4 Chargeable with electrical energy.

The charging station 2 has an integrated voltmeter 22 for detecting and monitoring a mains voltage as a network parameter U.N. of the supply network 8th on. The voltmeter 22 is to a controller 24 led a charge controller not shown in detail. The controller 24 regulates and / or adjusts based on the detected mains voltage U.N. a charging current IL or a charging power PL for loading the motor vehicle 4 or its energy storage 20 on. The controller controls and / or regulates this 24 For example, a power converter, in particular a DC converter, which between the grid point 6 and the charging point 10 is interconnected.

The following is based on the 2 a method for loading the motor vehicle 4 by means of the charging station 2 explained in more detail. The 2 shows a mains voltage charging current or power voltage charging power diagram, wherein along the horizontal axis of abscissa (x-axis) is the mains voltage U.N. plotted, wherein along the perpendicular thereto ordinate axis (y-axis) a normalized charging current IL or a normalized charging power PL is shown. The solid line shows the (normalized) course of the charging current IL or the charging power PL for different mains voltages U.N. ,

In the 2 is the mains voltage U.N. in units of a normal stress Ustandard indicated, this means that the axis position "1.000" denotes a voltage value at which the mains voltage U.N. equal to the normal voltage Ustandard is. With a 230 V supply network, the normal voltage is Ustandard 230 V.

According to the method, the charging current IL or the charging power PL based on the detected mains voltage U.N. set. In particular, the charging current IL here by the mains voltage U.N. controlled and / or regulated. Preferably, the controller calculates 24 based on the detected voltage value of the mains voltage U.N. a power value for the charging power PL which the motor vehicle 4 from the charging point 10 without significantly affecting the grid stability of the supply network 8th is effected.

The controller 24 compares the detected mains voltage U.N. with a first and a second threshold range S1 and S2 which is in a memory of the controller 24 are deposited. Between the threshold ranges S1 and S2 is a tension band B formed, which has a range of values of the mains voltage U.N. indicates in which the motor vehicle 4 with the maximum permissible charging current IL or the maximum permissible charging power PL ("1.00") is supplied. This means that the charging current IL or the charging power PL in the tension band B is essentially constant.

Relative to the normal voltage Ustandard extends the threshold range S2 -10% of normal stress Ustandard to -5% normal tension Ustandard , The threshold range S2 here has a lower voltage limit G1 and an upper voltage limit G2 as boundary values as well as an intermediate value arranged between them M on. The voltage limit G1 thus corresponds to -10% of normal stress Ustandard that is 0.9 Ustandard , where the voltage limit G2 equal to 5% of normal stress Ustandard that is 0.95 Ustandard , is. The mean M is between the voltage limits G1 and G2 at -7.5% of normal stress, that is 0.925 Ustandard arranged. The voltage limits G1 . G2 and the mean M are here stored thresholds, based on which the controller 24 the charging current IL or the charging power PL controls and / or regulates.

Below the mains voltage U.N. the upper voltage limit G2 of the threshold range S2 , so is the charging current provided IL or the charging power PL the charging station 2 from the controller 24 reduced. In the voltage range between the voltage limit G2 and the mean M becomes the charging current IL or the charging power PL here linear between 100% ("1.00") of the possible charging current IL or the charging power PL at the voltage limit G2 , and 50 % ("0.50") of the possible charging current IL or the charging power PL at the mean M varied. In case of falling below the mean value M becomes the charging current IL or the charging power PL in the voltage range between the mean value M and the voltage limit G1 to a stored minimum value A regulated or discontinued. When the mains voltage drops U.N. below the voltage limit G1 becomes the charging current IL or the charging power PL set to zero, that means the charging of the motor vehicle 4 is terminated or interrupted. Increases the mains voltage U.N. again, the charge current will be IL or the charging power PL when reaching or exceeding the voltage limits G1 . G2 or the mean M correspondingly increased again.

Relative to the normal voltage Ustandard extends the threshold range S1 of +5% of the normal voltage Ustandard up to +10% normal tension Ustandard , This means that the voltage band B extends between ± 5% of the normal voltage. The threshold range S1 here has a lower voltage limit G3 and an upper voltage limit G4 as marginal values as well as on. The voltage limit G3 thus corresponds to +5% of normal stress Ustandard that is 1,050 Ustandard , where the voltage limit G2 equal to +10% of normal stress Ustandard that is 1,100 Ustandard , is. The voltage limits G3 . G4 are analogous to the voltage limits G1 and G4 or the mean M deposited thresholds, based on which the controller 24 the charging current IL or the charging power PL controls and / or regulates.

Exceeds the mains voltage U.N. the lower voltage limit G3 of the threshold range S1 , so is the charging current provided IL or the charging power PL the charging station 2 from the controller 24 reduced. In the voltage range between the voltage limit G3 and the voltage limit G4 becomes the charging current IL or the charging power PL here linear of 100% ("1.00") of the possible charging current IL or the charging power PL at the voltage limit G3 , to 0% ("0.00") of the possible charging current IL or the charging power PL at the voltage limit G4 varied. As a result, the charging process becomes too high mains voltages U.N. interrupted or terminated. Drops the mains voltage U.N. again, the charge current is IL or the charging power PL when reaching or exceeding the voltage limit G4 correspondingly increased again linearly.

To support the stability of the mains voltage U.N. , ie to reduce the fluctuations or deviations from the normal value Ustandard , It is procedurally provided that when reaching or falling below the voltage limit G2 a reactive power PB from the motor vehicle 4 in the direction of the supply network 8th is fed. This will cause an undervoltage, resulting in a failure of the charging station 2 and / or the motor vehicle 4 can lead, counteracted.

The method continues to provide that the voltage limits G1 to G4 and the mean M , ie the threshold ranges S1 and S2 , by means of the voltmeter 22 monitored network stability can be varied. This will cause a local overload of the supply network 8th avoided, causing the voltage band B is reliably maintained.

The controller 24 monitored by the voltmeter 22 continue a network frequency fN the mains voltage U.N. , where the maximum allowable charging power PL or the maximum permissible charging current IL is reduced at a negative frequency change and increased accordingly at a positive frequency change. This means that the amplitude of the power or current value in the voltage band B is varied based on the detected network frequency.

The charging point 10 is by means of a through the controller 24 controlled switching device 26 between the phases L1 . L2 . L3 of the supply network 8th switchable. This means that the charging point 10 by means of the switching device 26 switchable to one of the phases L1 . L2 . L3 of the supply network 8th is guided. According to the method, it is provided here that switching is made from a first phase to a second phase when the monitored mains voltage U.N. or the network frequency fN the first phase a threshold, for example, the voltage limit G2 or G3 reached or fallen below.

By monitoring the mains voltage U.N. of the supply network 8th becomes the current network situation of the supply network 8th during the charging process of the motor vehicle 4 considered. This will ensure that the electricity or utility network 8th in the course of a charging process of the motor vehicle 4 not overloaded.

The invention is not limited to the embodiment described above. Rather, other variants of the invention can be derived therefrom by the person skilled in the art without departing from the subject matter of the invention. In particular, all the individual features described in connection with the exemplary embodiment can also be combined with each other in other ways, without departing from the subject matter of the invention.

For example, a charging station 4 with several charging points 10 conceivable, the charging current IL or the charging power PL at a connection of another motor vehicle 4 at a second charging point 10 the charging station 2 is reduced. As a result, the newly connected motor vehicle 4 a larger charging power PL allows.

It is equally conceivable that instead of the mains voltage U.N. the grid frequency fN or a mains power or a network power or a (network) power factor is monitored as a network parameter.

LIST OF REFERENCE NUMBERS

2

charging station

4

motor vehicle

6

Power supply / Power point

8th

supply network

10

charging point

12

charge cable

14, 16

plug

18

Loading interface

20

energy storage

22

voltmeter

24

controller

26

switching device

U.N.

Network parameters / mains voltage

IL

charging current

PL

charging power

Ustandard

normal stress

S1, S2

threshold range

B

voltage band

G1, G2, G3, G4

Voltage limit / threshold

M

Mean / threshold

A

minimum value

PB

reactive power

fN

power frequency

L1, L2, L3

phase

Claims (8)

Method for charging an electrically driven or drivable motor vehicle (4), in which the motor vehicle (4) is connected to a charging point (10) of a charging station (2) fed from a single- or multi-phase supply network (8), wherein during a charging process in which the motor vehicle (4) is charged with a charge current (IL) taken from the charging point (10), a network parameter, in particular the mains voltage (UN) and / or the network frequency (fN) of the supply network ( 8) is monitored, and - Wherein the charging current (IL) is set on the basis of the network parameter (UN, fN). Method according to Claim 1 , characterized in that the network parameter (UN, fN) deposited with a first and with a second Threshold range (S1, S2) is compared, wherein the charging current (IL) is lowered when the network parameter (UN, fN) reaches or falls below the first or second threshold range (S1, S2). Method according to Claim 2 , characterized in that when reaching or falling below the second threshold range (S2), a reactive power (PB) from the motor vehicle (4) in the supply network (8) is fed to the grid stabilization. Method according to Claim 2 or 3 , characterized in that the first threshold range (S1) and / or the second threshold range (S2) is adjusted based on a grid stability of the supply network (8). Method according to one of Claims 1 to 4 , characterized in that the supply network (8) is a multiphase AC or AC network of a number of phases (L1, L2, L3), the network parameter (UN, fN) being monitored individually for each phase. Method according to one of Claim 5 , characterized in that the charging point (10) is phase-selectively switchable to in each case one of the phases (L1, L2, L3) of the supply network (8), wherein from a first phase (L1, L2, L3) to one of the other phase ( L1, L2, L3) is switched when the network parameter (UN, fN) of the first phase (L1, L2, L3) reaches or falls below a threshold value (G2, G3). Method according to one of Claims 1 to 6 , characterized in that the charging current (IL) at a connection of another motor vehicle (4) to another charging point (10) of the charging station (2) is reduced. Charging station (2) for charging an electrically driven or drivable motor vehicle (4), comprising - a charging point (10) fed from a supply network (8) for connecting the motor vehicle (4), and - a controller (24) for carrying out the method according to one of the Claims 1 to 7 ,

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