WO2012163396A1

WO2012163396A1 - Limiting power or current intensity in charging devices

Info

Publication number: WO2012163396A1
Application number: PCT/EP2011/058823
Authority: WO
Inventors: Alexander Kepka; Maximilian Korff; Florian SALOMON; Andreas Zwirlein
Original assignee: Siemens Aktiengesellschaft
Priority date: 2011-05-30
Filing date: 2011-05-30
Publication date: 2012-12-06

Abstract

The invention relates to a method for limiting the electrical power or the electrical current intensity during the charging of traction batteries (16, 36, 56) of electrically driven vehicles (18, 38, 58). According to said method, a plurality of charging devices (10, 30, 50, 70) are attached to a branch (3) of a power supply network (1), and a respective traction battery (16, 36, 56) of an electrically driven vehicle (18, 38, 58) can be charged on each of said charging devices. In the method, from the plurality of charging devices (10, 30, 50, 70) those charging devices (10, 30, 50) are identified which are respectively electrically connected to a vehicle (18, 38, 58) at an identification time (t1) in order to charge the traction battery (16, 36, 56) of said vehicle. For the identified charging devices (10, 30, 50), a respective priority characteristic (P1, P2, P3) is determined, which characteristic is at least temporarily assigned to the respective vehicle connected to the charging device or to the user of said vehicle. Using said priority characteristic, a respective limiting value (K1, K2, K3) for the electrical power or for the electric current intensity is determined for the identified charging devices (10, 30, 50), and the electrical power or the electric current intensity of the identified charging devices (10, 30, 50) is limited respectively to the determined limiting value (K1, K2, K3).

Description

description

Power or current limitation in charging devices The invention relates to a method for limiting the electric power or the electric current when charging traction batteries of electrically driven vehicles and a control device. It is expected that in the future electrically drivable

Vehicles will be traveling in large numbers on the streets. Such an electrically powered vehicle includes a traction battery, which provides the Benö for driving ^¬ preferential electrical energy. Discharged traction batteries must be recharged if necessary by means of a charging device. Therefore, in the future will be installed in a larger number of charging devices for electrically powered vehicles, for example, at gas stations, parking ^¬ zen, parking garages or at the roadside.

When desired short charging times, the charging devices must provide considerable electrical power or current levels for charging the traction batteries available. In particular, when a plurality of charging devices supplied by a branch of a gieversorgungsnetzes energy with electrical energy ^¬ the example, there is a risk that the branch or the power supply network may be overloaded.

The invention has for its object to provide a method and an apparatus that allow to operate a plurality of charging devices safely and reliably to a branch of a power supply network.

This object is achieved by a method and a control device according to the independent claims. Advantageous embodiments of the method are specified in the dependent claims. According to the invention, a method for limiting the electric power or the electric current when charging traction batteries of electrically driven vehicles, wherein at a branch of a power supply network, a plurality of charging devices is connected to each of which a traction battery of an electrically drivable ^¬ ble vehicle is chargeable, wherein in the process

from the plurality of charging devices, those charging devices are determined which are each electrically connected to a vehicle at a determination time in order to charge its traction battery,

- for the determined charging devices each have a priority parameter is determined, the zumin- each connected to the vehicle La ^¬ signaling device or its user is assigned least temporarily (or permanently),

- a loader-specific or charging-specific limit value for the electrical power or for the electrical current is determined for the determined charging devices using this priority characteristic, and

- The electrical power (charging power) or the electric current (charging current) of the determined Ladeein ^¬ directions (from the determination time) is limited in each case to the he ^¬ mediated limit.

This ensures ver ^¬ avoided overloading of the branch of the power grid or the power supply system. The electric power can optionally correspond to the power consumption or the power output of the charging device. The determination time may be, for example, the current time or a future time. This method is particularly advantageous in that the electric power or the current intensity of the Ladeein ^¬ directions is limited in each case to the individual charging device limit. This limit can be the maximum value ^¬ indicate to the electric power or electric current at the charging facility for the purpose of charging the driving battery can be removed. Alternatively, the Limit value also specify the maximum power or the maximum current ^¬ strength, which may be removed from the power supply network of the charging device (in this case, the power loss within the charging device is taken into account).

The limit value may be determined such that when the vehicle or its user has a high priority, the limit value corresponds to a greater power or a greater current than to a low priority of the vehicle or its user. Thus advantageously allows that, for a high priority of the vehicle or its groove ^¬ decomp the driving battery can be charged with a larger power, or a larger current than at low priority of the vehicle or its user.

The limit value can be determined such that it corresponds to at least one predetermined minimum power or minimum current that is independent of the priority of the respective vehicle or its user. This is beneficial ^¬ way legally to ensure that every driving battery can be charged at least with the preselected minimum performance or minimal current. It is thus ensured that a charging process always takes place.

The method can proceed such that are determined by a central control device, the loading means, which are for determining the time of each electrically connected to an accelerator ^¬ convincing. In this case, the charging devices are determined by a central control device. By means of such a central control device a plurality of charging devices can be controlled and / or the charging devices electrically connected at the time of determination can be determined.

The method can also run such that the central control ^device receives at least one status message from the charging ^device and uses this status message to It is known which charging devices are each electrically connected to a vehicle at the time of determination. By means of receiving at least one such status message, the central control device can easily and reliably detect which of the charging devices are electrically connected to a vehicle. In particular, when installing new charging devices, the method can be easily adapted to an increasing number of charging devices, without the need for complex changes to be made to the control device.

The method can proceed in such a way that the electrical power or the electrical current strength of the determined charging devices is limited to the respectively determined limit value by a central control device.

In this case, the method can proceed in such a way that in each case a command message is sent to the ascertained charging devices by the control device for limiting the electrical power or the electrical current strength. This command message may contain information about the respective limit. Upon receipt of the command message, the charging devices limit their electrical power or the electrical current to the respective limit value.

The method may be such that the threshold Kx is exploited using the relationships

and

Knead ^~ Kges ⁿ ^ min is determined, where

Kx is the threshold value for the charging device that loads the vehicle x,

Px to the vehicle or its x users associated Priori ^¬ tätskenngröße,

n the number of charging devices determined,

S the weighting quantity for the priority parameters,

Kges the electrical power that can be provided at the branch of the energy supply network or the electric current that can be provided at the branch of the energy supply network, and

Kmin is the minimum electric power or the minimum electric power available for each vehicle regardless of its priority.

The size of the limit value Kx for the respective charging device is dependent on the priority parameter Px of the vehicle to be charged with this charging device or its user. It is advantageous that the limit values for the load devices in a wide range can be influenced by the priority characteristic ^¬ sizes and / or the weight and size so that the loads of the vehicles with respect to the charging efficiency or the charging current (and therefore the load) in a wide range can be influenced.

According to the invention, a control device for limiting the electric power or the

electric current when charging traction batteries

electrically driven vehicles, which is designed to carry out the aforementioned method. This control device also has the advantages that are mentioned above in connection with the method according to the invention.

In the following the invention on the basis ^of an exemplary ^embodiment is explained in detail. This is in Figure 1 shows an embodiment with four charging devices and with a central control device, in

FIG. 2 shows a first exemplary distribution of the limit values when carrying out the method and in FIG

FIG. 3 shows a second exemplary distribution of the limit values when carrying out the method.

FIG. 1 schematically shows a power supply network 1, which in the exemplary embodiment is a medium-voltage power supply network or a low-voltage power supply network. At a branch 3 of this power supply network 1 AC or AC voltage ^¬ alternating voltage is provided. The branch 3 is connected to a transformer 5, by means of which the voltage level can be adjusted to a required size

and / or galvanic isolation can be realized.

This transformer 5 is optional, it may also be omitted in other embodiments.

The branch 3 of the power supply network 1 is electrically connected to a first charging device 10 via the transformer 5 and power conductor 7 (power cable 7). This first charging device 10 has a first power ^¬ path 12, electrically drivable over which the certificate from the branch 3 of the power supply system 1 to a first electric power driving battery 16 of a first

Vehicle 18 is passed. The first power path 12 ent ^¬ holds, for example, electronic components of the power ^¬ electronics, fuses, switching devices and / or measuring equipment. The power line to the first drive battery 16 is effected by means of a first charging cable 19. Furthermore, the first charging device 10 has a first control device 20 which monitors and controls the operation of the first charging device 10. Furthermore, the branch 3 of the power supply network 1 is electrically connected by means of the power conductor 7 to a second charging device 30. The second charging device 30 has - similar to the first charging device 10 - a second power path 32 which transmits by means of a second charging cable 35 from the branch 3 of the power supply network 1 stam ^¬ ing electrical energy to a second drive battery 36 of a second electrically driven vehicle 38. The second charging device 30 has a second Steuerein ^¬ direction 40, which monitors the operation of the second charging device 30 and controls.

In the same way, the branch 3 of the power supply network 1 is electrically connected by means of the power conductors 7 to a third charging device 50. The third charging device 50 has a third power path 52 which, by means of a third charging cable 55, transmits the electrical energy originating from the branch 3 of the energy supply network 1 to a third traveling battery 56 of a third electrically driven vehicle 58. The third Ladeeinrich ^¬ device 50 has a third control device 60, which monitors the operation of the third charging device 50 and controls.

Furthermore, the branch 3 of the power supply network 1 is electrically connected to a fourth charging device 70 by means of the power conductors 7. The fourth charging device 70 has a fourth power path 72, which originates from the branch 3 by means of a fourth charging cable 75

electrical energy can be transferred to a further drive battery of a wei ^¬ direct electrically driven vehicle. In the fourth embodiment, the charging device 70 is propelled ^¬ generating free, thus not electrically connected to a vehicle. The fourth charging device 70 has a fourth Steuerein ^¬ direction 80, which monitors the operation of the fourth charger 70 and controls. For example, each of the Charging devices 10, 30, 50 and 70 each charged ^¬ trainee battery with active power up to 44 KW charge.

The first control device 20 of the first charging device 10, the second control device 40 of the second charging device 30, the third control device 60 of the third charging device 50 and the fourth control device 80 of the fourth charging device 70 are electrically connected by means of communication conductors 82 (communication cables 82) to a central control device 84 , The central control device 84 has a communication unit 86 and a control unit 88. By means of the communication unit 86, the central STEU ^¬ ereinrichtung 84 messages from the charging devices 10, 30, 50 and 70 and received by the power supply system 1 and send messages to the charging devices 10, 30, 50 and 70th By means of the control unit 88, the central control device 84 processes among other things the received messages and carries out control tasks. The control unit 88 is electrically connected to a memory unit 90, in which inter alia a first priority parameter PI is stored, which is the first electrically drivable vehicle 18 or a user of the first

electrically driven vehicle 18 is at least temporarily assigned. For example, this first priority characteristic ^variable PI may have been specified in a power delivery contract that the user or an operator of the vehicle 18 has concluded with a power supply company. In general, the priority parameters can assume a value greater than or equal to 1. Low values of the priority parameter correspond to a low priority, high values of the priority parameter correspond to a high priority. If a low priority exists, the traction battery will be charged with comparatively lower power or current values than when there is a high priority.

Further, in the storage unit 90, a second Priori ^¬ tätskenngröße P2 of the second vehicle 38 or its user and a third priority parameter P3 of the third vehicle 58 or its user stored.

In addition, a total ready position quantity Kges and a minimum prepared size Kmin are stored in the memory unit 90. The total delivery size Kges describes the current look at the branch 3 of the power supply network be maximum ^¬ reitstellbare electric power or the maximum suppliable to the branch 3 of the electrical power supply network. The minimal provision quantity Kmin ^¬ writes the minimum electric power or electric current that should be available for each vehicle regardless of its priority when charging the traction battery.

Also in the storage unit 90 of the central control device is stored ^¬ a weighting size S 84, which is also referred to as Spreizgröße or Spreizpotenz. This weighting variable S can assume values greater than 1. The weighting variable S indicates how much the priorities or priority parameters are weighted. In other words, the weighting quantity S indicates how far the range of the limit values to be assigned to the charging devices is spread. In Figures 2 and 3, a distribution of threshold values for the electric power (charging power) or for the electric current (charging current) at is represented by ^¬ out the method between times tO and tl, and between the time points tl and t2 by way of example. In folic constricting a Ausführungsbei ^¬ play of the method is described for limiting the electric power when charging of driving battery electric vehicles drivable with reference to FIGS. 1 to 3 At time TO (see FIG. 2) is loaded, the first driving battery 16 of the f th ^¬ electrically powered vehicle 18 only by the first charging device 10. However, the second traction battery 36 and the third traction battery 56 are notwithstanding the representation of FIG. 1, they are not yet electrically connected to the charging devices 30 and 50 and are not charged at the time t0. To load stands at the branch 3 a maximum deployable electrical active power available that speaks ent ^¬ the total provision amount Kges. The first charging device 10 is controlled by the first control device 20 so that the first Fahrbatte ^¬ rie 16 can be charged with the total available at the branch 3 of the power supply network 1 electrical real power Kges. In this case, the limit value K1 for the electric power of the first charging device 10 corresponds to the total supply quantity Kges: K1 = Kges. (The Verlustleis ^¬ tion of the charging device is neglected here.) From the time tl to the second charging device 30 in addition to the second traction battery 36 of the second electrically driven vehicle 38 and the third charging device 50, the third traction battery 56 of the third electrically drivable ^¬ ble vehicle 58 charged. Therefore, the controller 40 of the second charging device 30 sends a status message 92 via the communication conductor 82 to the central control device 84. This status message 92 contains the information that is to be charged from the time tl, the second driving ^¬ battery 36, that is to say that at the time tl the charging process for the second traction battery 36 begins. The time tl is here therefore the determination time.

Also, the control device 60 of the third charging device 50 sends a status message 94 over the communication conductors 82 to the central control device 84. This status message 94 contains the information that the third driving battery to be charged 56 from the time ^¬ point tl, which means that the time tl the charging process for the third drive battery 56 begins.

The central control device 84 receives via the communi ^¬ nikationseinheit 86 these status messages 92 and 94 and evaluates their contents by means of the control unit 88th Because the Central control device 88 receives no new status messages from the first charging device 10 and the fourth charging device 70 is known at the central control device 84, that at the time tl the charging at the first charging device 10 is continued and that also from the time tl to the fourth Charging device 70 no traction battery is loaded. Therefore, upon receiving the status messages 92 and 94 at the central controller 84, the information is that from the time tl at three charging devices simultaneously traction batteries of vehicles to be loaded, namely at the first charging device 10, at the second charging device 30 and at the third Charging device 50. Thus, those charging devices 10, 30 and 50 have been determined, which are each electrically connected to the determination time tl with a vehicle 18, 38 or 58 to the trailing battery 16, 36 or 56 to la ^¬ den. The number of charging devices determined is therefore 3 (n = 3). Alternatively or additionally, the first control means 20 may send a status message 93 to the central Steuerein ^¬ direction 84, wherein the status message 93 contains the Informa ^¬ functions that the first charging device 10 also charges the driving battery sixteenth Likewise, the fourth controller 80 may also send a status message 96 to the central controller 84, the status message 96 containing the information that the fourth charger 70 is still not charging any traction battery. After receiving the status messages 92, 93, 94 and 96 are in this variant in the central controller 84, the

Information that from the time tl (only) at the three charging devices 10, 30 and 50 are each loaded simultaneously a driving battery of a vehicle. Further, located in the storage unit 90 of the central STEU ^¬ ereinrichtung 84, a characteristic value for the Kges at the branch 3 of the power supply system 1 products provisionable electrical power or electrical current before, this Characteristic value is the so-called total supply size Kges. In the exemplary embodiment, this characteristic value is the total electrical power that can be provided at the branch 3 of the energy supply network 1 or the maximum amount that can be provided. For example, information about the total provisioning parameter Kges has already been transmitted from the energy supply network 1 to the central control device 84 via the communication conductors 82. In the exemplary embodiment, the total supply size Kges = 100 kW. In another embodiment, it may also be a different size at the total READY ^¬ lung size, for example, the maxi at the branch 3 of the power supply system 1 ^¬ times provisionable electrical current.

Also, located in the storage unit 90 of the central control device 84 before the minimum ^¬ provision amount Kmin. The minimum provision amount Kmin is the minimum electrical ^¬ cal power or the minimum electric current is that needs to be provided for each vehicle, regardless of its priority loading available. In the embodiment, be ^¬ carries the minimum provision amount Kmin = 5 kW. Further, 90 of the central control device 84 are in the storage unit, the first priority parameter PI, the second Priori ^¬ tätskenngröße P2 and the third priority parameter P3 abge ^¬ stores. In the embodiment, this priority characteristic ^¬ sizes have the values: PI = 1.5; P2 = 3; In addition, the weighting quantity S is stored in the memory unit 90, its value S = 2 in the exemplary embodiment. The control unit 88 then determines the limit values K1, K2 and K3 for the charging devices 10, 30 and 50. These limit values each describe one Leistungsungskontingent or a stream contingent, which is the corresponding charging station to ^¬ ordered. The size of the limits will include, inter alia loading of the true total provision amount Kges, the number n of the charging devices, the charging to the determination time point Fahrbat ^¬ criteria of vehicles and the respective priority Px of the vehicle or of the user. First, the control unit 88 determines the threshold value K1 for the first charging device 10. This is done using the following relationships:

pS

(1) K _x Knet ^~ + K mm

Σ Pj

i = \

(2) K _ne t = Kg _es - nÄT _mm where is

Kx is the limit value for the charging device that charges the vehicle x (i.e., Kx describes the electric power or the electric current that can be assigned to a charging device and thus to the vehicle connected to this charging device (assignment characteristic)),

Px the priority parameter assigned to the vehicle x or its user,

n the number of charging devices determined,

S the weighting quantity for the priority parameters,

Kges the reitstellbare be ^¬ at the branch of the power supply mains electrical power or the provisioned at the branch of the power supply network electrical current (total delivery size)

Knows the electric power or electric current (net return size) to be distributed taking into account Kmin

Kmin the minimum electric power or electric

Amperage is available for each vehicle regardless of its priority (minimum provision size). The values required to determine the limit value Kl are already present at the control unit 88 or the control unit 88 reads these values from the memory unit 90. First, the control unit 88 determines the size Knet according to the relationship (2).

Knead = Kges - n * Kmin

Kneading = 100 kW - 3 * 5 kW

Kneading = 85 kW

Thereafter, the control unit 88 determines the threshold value K L for the first charging device 10.

Ki Knead ^' mm

Ki = 10.3 kW

In the same way, the control unit 88 determines the limit value ^{K 2} for the second charging device 30.

K ₂ Knet ^'+ K mm

K, 26.1 kW

Furthermore, the control unit 88 determines the limit value K3 for the third charging device 50. Kneading + K mm

63, 6 kW

Then, the central control device 84 transmits via the communication unit 86, a first command message 95 to the first charge means 10. This first command message 95 contains information about the threshold Kl and op tionally ^¬ additional information about the time tl. By means of the command message so that each ^¬ stays awhile control means of the loading device is instructed in general, the electric power or the electrical current of the La ^¬ signaling device (in the embodiment, for example, the electrical active power output of the charging device) from the discovery ^¬ time (or from the time of arrival of the Komman ^¬ donachricht the charging device) each limit to the limit value Kx.

In the embodiment, the first control means 20 of the first charging device 10, the electric power (Ladeleis- circuit) of the first charging device 10 from the time tl is instructed so by means of the Kommandonach ^¬ report 95 to limit to the limit value Kl. This means that the charging ^{¬ device} 10 is instructed to charge the ^traction battery 16 from the determination time tl maximum with the charging power Kl = 10.3 kW.

Upon receipt of the command message 95, the control device 20 of the charging device 10 limits the electrical power of the charging device 10 to the latter from the time t 1 onwards. sen limit value Kl (ie in the embodiment to a maximum of 10.3 kW). Then, from the time t1, the first traction battery 16 connected to the first charging device 10 can be charged to a maximum of the power K1 = 10.3 kW. This is also shown in the diagram of Figure 3: From the time tl the traction battery 16 is charged at the first Ladeeinrich ^¬ tion 10 only a maximum of the power Kl = 0.103 * Kges = 10.3 kW. Furthermore, the central control device 84 transmits via the communication unit 86, a second command message 98 to the second charge means 30. This second command message 98 contains information about the threshold K2 and op tionally ^¬ additional information about the time tl. Joint means of the second command message 98, the second control ^¬ device 40 of the second charging device 30 is instructed, the electric power (load power) of the second charging device 30 from the time tl to the threshold value K2 to begren ^¬ zen. Upon receipt of the command message 98, the second control device 40 limits the electrical power of the second charging device 30 from the time t1 on this limit K2 (ie in the embodiment to a maximum of 26.1 kW). Thereupon, the second traction battery 36, which is connected to the second charging device 30, can be charged with a maximum of the power K2 = 26.1 kW starting from the time t1. This is also shown in the diagram of Figure 3: From the time tl, the second traction battery 36 is charged at the second Ladeeinrich ^¬ device 30 only a maximum of the power K2 = 0.261 * Kges = 26.1 kW.

Similarly, the central controller 84 sends via the communication unit 86, a third command ^¬ message 99 to the third charging device 50. This third command message 99 contains information about the threshold value K3 and optional additional information about the time tl. By means of the third command message 99, the third control device 60 of the third charging device 50 is instructed to control the electrical power (charging power) of the third charging device 50. deeinrichtung 50 from the time tl to the limit K3 limit. Upon reception of the third command message 99 toward the third control means 60 limits the electrical power of the third charging device 50 from the time tl to this limit value K3 (so in the exemplary embodiment ma ^¬ ximal 63, 6 kW). Thereupon, from the time t1, the third traction battery 56 connected to the third charging device 50 can be charged to a maximum of the power K3 = 63.6 kW. This is also shown in the diagram of FIG. 3: From the time t1, the third traction battery 56 at the third charging device 50 is only charged at a maximum with the power K3 = 0.636 * Kges = 63.6 kW.

This ensures that the be ^¬ reitstellbare maximum at the junction 3 of the power supply system 1 electric power Kges = 100 kW itself is then not exceeded even after the time tl when at each of the three charging devices 10, 30 and 50 of the limit value Kl, K2 or K3 the

electric power is fully utilized. (If the command messages 95, 98 and 99 do not contain information about the determination time tl, then the controllers 20, 40, 60 of the charging devices 10, 30, 50 limit the electrical power of the charging devices from the receipt of the command messages 95, 98 and 99 to the limit Kl, K2 or K3.)

When at time t2 the number of simultaneously la ^¬ Denden driving battery change, the process described is repeated.

In the method described so far, the power loss occurring in the charging devices has been neglected. However, this power loss can also be taken into account in another method sequence. Then the power output of the respective charging device to the traction battery is not limited by the control device of the respective charging device to the limit value Kx, but rather the power consumption of the charging device respective charging device of the branch 3 of the power supply network 1 is limited to the limit Kx.

While limiting the electric power of Ladeeinrichtun- gen the reaction time of the vehicles 18, 38 and 58 can be beach ^¬ tet, ie the time between sending the command message and the compliance with the new limit. If the new limit value is not met within a specified period of time, then the charging process can be interrupted.

In the embodiment, a method for limiting the electric power when charging traction batteries of electric drivable vehicles has been described. By means of a similar method, it is also possible to carry out a limitation of the electric current when charging traction batteries of electric drivable vehicles. The quantities Kges, Kmin and Kx then describe current values instead of power values.

A method and a control device have been described, which make it possible to operate a plurality of charging devices safely and reliably at a branch of a power supply network. In this case, the electrical power of those charging devices, at which simultaneously

Traction batteries are charged, each limited to a limit. This limit value is determined using a priority ^parameter which is assigned at least temporarily to the respective vehicle or its user connected to the charging device. This ^over-¬ utilization of the branch of the power supply network is reliably avoided in particular.

Claims

claims

1. A method for limiting the electric power or the electric current when charging traction batteries (16, 36, 56) electrically driven vehicles (18, 38, 58), wherein at a branch (3) of a power supply network (1) a plurality of charging devices (10, 30, 50, 70) is connected, to each of which a traction battery (16, 36, 56) of an electrically driven vehicle (18, 38, 58) is rechargeable, wherein in the method

- From the plurality of charging devices (10, 30, 50, 70) those charging devices (10, 30, 50) are determined, which at a determination time (tl) are each electrically connected to a vehicle (18, 38, 58) to its battery (16, 36, 56) to charge,

a respective priority parameter (PI, P2, P3) is determined for the determined charging devices (10, 30, 50), which is at least temporarily assigned to the respective vehicle or its user connected to the charging device,

- For the determined charging devices (10, 30, 50) using this priority characteristic in each case a limit value (Kl, K2, K3) for the electric power or for the electric current is determined, and

- The electrical power or the electric current of the determined charging devices (10, 30, 50) in each case to the determined limit value (Kl, K2, K3) is limited.

2. The method according to claim 1,

d a d u r c h e c e n c i n e s that

- the threshold value is determined so that at a high Prio ^¬ rity (P3) of the vehicle or the user of the limit value (K3) of a higher power or a large current corresponding than a low priority (PI) of the driving ^¬ zeugs or its user ,

3. The method according to claim 1 or 2,

characterized in that - The limit value (Kl) is determined so that it corresponds to at least a predetermined minimum power or minimum current (Kmin), which is independent of the priority (PI) of the respective vehicle or its user.

4. The method according to any one of the preceding claims,

d a d u r c h e c e n c i n e s that

- The charging devices (10, 30, 50) are determined by a central control device (84), which are at the determination time (tl) each electrically connected to a vehicle ^¬ the.

5. The method according to any one of the preceding claims,

d a d u r c h e c e n c i n e s that

- the central control device (84) at least one status ^¬ object (92, 94) of the charging means (30, 50) and to the basis of this status message (92, 94) is detected, which load means (10, 30, 50) for investigative ^¬ time (tl) are each electrically connected to a vehicle (18, 38, 58).

6. The method according to any one of the preceding claims,

d a d u r c h e c e n c i n e s that

- The electrical power or the electric current of the determined La ^¬ deeinrichtungen (10, 30, 50) is limited to the respectively determined limit value (Kl, K2, K3) by a central control device (84).

7. The method according to claim 6,

d a d u r c h e c e n c i n e s that

- By the control device (84) for limiting the electrical power or the electric current respectively a command message (95, 98, 99) to the determined charging ^{¬ facilities} (10, 30, 50) is sent.

8. The method according to any one of the preceding claims,

d a d u r c h e c e n c i n e s that

- the limit using relationships Κχ kneading + K mm

and

Knet ^~ Kges ⁿ ^ min is determined, where

Kx is the threshold value for the charging device that loads the vehicle x,

Px the priority parameter assigned to the vehicle x or its user,

n the number of charging devices determined,

S the weighting quantity for the priority parameters,

Kges the ^¬ at the branch of the power supply network ^¬ reitzstellbare electrical power or provide the branch of the power grid electric current, and

Kmin is the minimum electric power or the minimum electric current that is available for each vehicle inde ^¬ gig of its priority is available.

9. Control device (84) for limiting the electric power or the electric current when charging traction batteries (16, 36, 56) of electrically driven vehicles (18, 38, 58) which is designed to carry out the method according to one of claims 1 to 8th.