Abstract:
A single-phase or multi-phase feed line is connected to a charging connection of the charging station, via which feed line the charge current flows to the charging connection of the charging station regardless of the load capacity identifier of the charge cable. An overload protection device is connected to and monitors the feed line. The overload protection device is an automatically switching overload protection device in which at least one identifier-specific trigger criterion is stored for each of at least two load capacity identifiers of the charging cable. The overload protection device is capable of automatically selecting the identifier-specific trigger criterion assigned to the load capacity identifier depending on the load capacity identifier of the charging cable, and of shutting off a switching device of the overload protection device arranged in the feed line depending on the selected trigger criterion.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and hereby claims priority to International Application No. PCT/EP2011/065442 filed on Sep. 7, 2011, the contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The invention relates to a charging station. 
         [0003]    Charging stations are distributed, for example, by Siemens AG under the product names Charge CP700A and CP500A. Said charging stations are equipped with an electric charging connection for connecting a charging cable of an electric vehicle, and are able to read, at the charging connection, a load capacity identifier specifying the electrical load capacity of the connected charging cable. The charging stations have overload protection devices for disconnecting the charging current in the event of an overload. 
         [0004]    Charging stations of this type are furthermore also known, for example, from the following documents: 
         [0005]    “IEC 61851-1:2010—Electric vehicle conductive charging system—Part 1: General requirements”, INTERNATIONAL STANDARD—IEC NORME INTERNATIONALE—CEI, X, XX, vol. ed2.0, No. IEC 61851-1:2010, Nov. 25, 2010 (11-25-2010), pages 1-104, XP008147718; 
         [0006]    DE 10 2009 034 886 A1 and DE 10 2009 034 887 A1. 
       SUMMARY 
       [0007]    One possible object is to specify a charging station which enables reliable monitoring of the charging process but yet can be manufactured inexpensively. 
         [0008]    The inventor proposes a charging station. With the charging station, a single-phase or polyphase feed line is connected to the charging connection of the charging station, via which feed line the charging current flows regardless of the load capacity identifier of the charging cable to the charging connection of the charging station, and the overload protection device is connected to the feed line and monitors same, wherein the overload protection device is an overload protection device with automatic switchover, in which in each case at least one identifier-specific tripping criterion is stored for at least two load capacity identifiers of the charging cable, and wherein the overload protection device is suitable for automatically selecting, on the basis of the load capacity identifier of the charging cable, the at least one identifier-specific tripping criterion assigned to the load capacity identifier and for disconnecting a switching device, arranged in the feed line, of the overload protection device on the basis of the selected tripping criterion. 
         [0009]    An important advantage of the proposed charging station is that the charging process can be completely monitored by a single overload protection device. The reason is that, in the case of the proposed charging station, the charging current is always conducted via one and the same single-phase or polyphase feed line to the charging connection of the charging station regardless of the load capacity identifier of the charging cable, with the result that it is possible to effectively control the charging process with a single overload protection device by simply monitoring said (central) feed line. It goes without saying that yet further or additional overload protection devices can, for example for reasons of redundancy, be connected to just said (central) feed line or at another location, if this is desired for reasons of safety. 
         [0010]    A charging station of this type can be manufactured in a particularly simple and therefore advantageous manner if the overload protection device has a memory in which the at least two identifier-specific tripping criteria are stored. 
         [0011]    The overload protection device preferably has a calculation device which is connected to the memory and is suitable for reading from the memory, on the basis of the respective load capacity identifier of the connected charging cable, the at least one identifier-specific tripping criterion which is assigned to said load capacity identifier and stored in the memory. 
         [0012]    With regard to a particularly high level of failsafety, it is considered to be advantageous if the overload protection device is directly connected to the charging connection and is suitable for reading the load capacity identifier of the connected charging cable by itself (or without the mediation of other components). 
         [0013]    By way of example, maximum current values, tripping characteristics and/or calculation guidelines, which need to be used by the calculation device during the evaluation of the measured charging current, are stored as load-capacity-specific tripping criteria. Therefore, the term tripping criterion is intended to be understood in the widest sense thereof. 
         [0014]    It is considered to be advantageous if the overload protection device has a measuring device which is connected to the calculation device and determines a measured value, which specifies the loading of the feed line, and transfers said measured value to the calculation device. The measuring device can be a current measuring device, for example, which measures the current through the feed line. 
         [0015]    The feed line can be a single-phase or polyphase feed line. In the case of a polyphase feed line, it is considered to be advantageous if the overload protection device with automatic switchover monitors one, several or all of the phases of the polyphase feed line. 
         [0016]    In the case of a polyphase feed line, it is considered to be advantageous if phase-specific monitoring and control takes place. Preferably, the overload protection device is suitable for disconnecting the phases of the polyphase feed line regardless of the symmetry of the current loading in the phases of the feed line. 
         [0017]    According to a particularly preferred configuration, it is provided that the switching device has an individually actuable switch for each phase of the polyphase feed line, and the overload protection device is configured such that it individually monitors the phases of the polyphase feed line and individually disconnects them in the event of an overload. 
         [0018]    In order to achieve remote parameter setting for the overload protection device, it is considered to be advantageous if the overload protection device has an interface module, and the control device of the overload protection device is programmed such that it is possible to change the identifier-specific tripping criteria by remote parameter setting. 
         [0019]    The inventor also proposed a method for monitoring the charging process of a charging station, a charging cable, which provides a load capacity identifier, of an electric vehicle being connected to the electric charging connection of said charging station. 
         [0020]    With respect to a method such as this, a feed line, which is connected to the charging connection of the charging station and via which the charging current flows, regardless of the load capacity identifier of the charging cable, to the charging connection of the charging station, is monitored by an overload protection device with automatic switchover, wherein, on the basis of the load capacity identifier of the charging cable, an identifier-specific tripping criterion assigned to the load capacity identifier is read from a memory of the overload protection device and a switching device arranged in the feed line is disconnected in the event of an overload, which is determined by the overload protection device according to the selected tripping criterion. 
         [0021]    With respect to the advantages of the method, reference should be made to the advantages of the charging station which are explained above, since the advantages of the charging station substantially correspond to those of the method. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    These and other objects and advantages of the present invention will become more apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: 
           [0023]      FIG. 1  shows a first exemplary embodiment of an arrangement having a proposed charging station, to which an electric vehicle is connected via a charging cable, 
           [0024]      FIG. 2  shows a second exemplary embodiment of an arrangement having a charging station, wherein an overload protection device of the charging station is directly connected to an identifier conductor of the charging cable and reads a load capacity identifier of the charging cable, 
           [0025]      FIG. 3  shows a third exemplary embodiment of an arrangement having a charging station, wherein the electric vehicle is charged by a voltage source, and 
           [0026]      FIG. 4  shows a fourth exemplary embodiment of an arrangement having a charging station, wherein a three-phase charging cable is connected to a three-phase feed line of the charging station. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0027]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
         [0028]    In the figures, the same reference signs are always used for identical or comparable components, for the sake of clarity. 
         [0029]      FIG. 1  reveals a charging station  10  which has a charging connection  20 , for example in the form a cable socket. A charging cable  30  is connected to the charging connection  20  of the charging station  10 , said charging cable electrically connecting the charging connection  20  to an electric vehicle  40 . The electric vehicle  40  is charged by the charging station  10  via the charging cable  30 . 
         [0030]    The charging station  10  comprises a control device  50  which is connected to the charging connection  20 . The control device  50  controls a controllable current source  60 , which generates the charging current I1 provided for charging the electric vehicle  40 . 
         [0031]    A feed line  70  is connected to the charging connection  20 , which feed line connects the charging connection  20  to the controllable current source  60  and enables the feeding in of charging current I1 into the charging cable  30 . In the exemplary embodiment according to  FIG. 1 , the feed line  70  is a single-phase feed line and has a phase conductor L 1  and a return conductor N. 
         [0032]      FIG. 1  shows that the charging cable  30  is likewise a single-phase charging cable and comprises two current-conducting conductors which are denoted with the reference signs L 1 ′ and N′. The conductor L 1 ′ is in this case connected to the phase conductor L 1  of the feed line  70  and the conductor N′ is connected to the return conductor N of the feed line  70 . In addition, the charging cable  30  comprises an identifier conductor LK, which enables a load capacity identifier K specifying the electric load capacity of the charging cable  30  to be read. The load capacity identifier K can specify, for example, that the charging cable  30  may be loaded with a maximum current of 16 A, 20 A, 32 A, 63 A or 70 A. 
         [0033]      FIG. 1  also reveals that the charging station  10  comprises an overload protection device  80  which is connected to the feed line  70 . The overload protection device  80  comprises a current measuring device  81 , which measures the current in the phase conductor L 1  of the feed line  70  and generates a corresponding measured current value Im. A calculation device  82  of the overload protection device  80  is connected to the current measuring device  81 . A memory  83 , in which a program module P is stored, is connected to said calculation device  82 . The program module P contains the control program which defines the operating mode of the calculation device  82  for monitoring the charging station  10 . 
         [0034]    In addition to the program module P, identifier-specific tripping criteria, which are denoted with the reference signs I16A, I20A, I32A, I63A and I70A, are stored in the memory  83 . The identifier-specific tripping criteria can be, for example, tripping characteristics or tripping curves or, alternatively, maximum values, such as maximum current values, maximum power values or maximum energy values, for example. 
         [0035]    Furthermore, the overload protection device  80  comprises an interface module  84  which is connected to the calculation device  82 . The interface module  84  enables remote parameter setting of the overload protection device  80 : by way of example, the parameters of program module P and, as a result, the operating mode of the calculation device  82  can be remotely set from the outside by the interface module  84 . In addition or alternatively, it is possible for the identifier-specific tripping criteria I16A to I70A to be replaced by other identifier-specific tripping criteria, if this appears to be necessary or advantageous. 
         [0036]    In addition, the overload protection device  80  is equipped with a switching device  85  which comprises a switch  85   a.  The switch  85   a  is connected to the phase conductor L 1  of the feed line  70  and is able to disconnect the charging current I1 through the phase conductor L 1  and, as a result, the charging current through the feed line  70  as a whole when a corresponding control signal ST is generated by the calculation device  82 . 
         [0037]    The arrangement according to  FIG. 1  can for example be operated as follows: 
         [0038]    once the charging cable  30  has been connected to the charging connection  20  of the charging station  10  and therefore an electrical connection has been established between the electric vehicle  40  and the charging station  10 , the control device  50  can read the load capacity identifier K from the identifier conductor LK, which is connected to the charging connection  20 , of the charging cable  30 . By way of example, the load capacity identifier K can specify the maximum charging current with which the charging cable  30  can be loaded. In the following text, it will be assumed by way of example that the load capacity identifier K indicates a maximum charging current of 32 A. Thus, the control device  50  will actuate the controllable current source  60  such that the charging current I1 absolutely does not exceed the maximum predefined charging current of 32 A or at least does not permanently exceed it. 
         [0039]    During the charging process, the overload protection device  80  will, at the same time or additionally, monitor the charging process and interrupt the charging process by the switching device  85  or by the switch  85   a  if the maximum charging current of 32 A is exceeded temporarily or for longer than a predefined time period. For this purpose, the calculation device  82  will read the load capacity identifier K specifying the load capacity of the charging cable  30  from the control device  50 . On the basis of the load capacity identifier K, the calculation device  82  will then in turn read the memory  83  and read an identifier-specific tripping criterion corresponding to the load capacity identifier K from the memory  83 . Since the load capacity identifier K specifies a maximum current of 32 A, the calculation device  82  in the exemplary embodiment according to  FIG. 1  will read the identifier-specific tripping criterion I32A from the memory  83  and use it to evaluate the measured current value Im. 
         [0040]    The calculation device  82  will evaluate the measured current values Im on the basis of the read identifier-specific tripping criterion I32A and check whether the charging cable  30  is overloaded. In the simplest case, the calculation device  82  can always operate the switching device  85  whenever the measured current value Im indicates a charging current that is higher than the maximum current value of 32 A. However, it is considered to be particularly advantageous if, in the event of the maximum current value of 32 A being exceeded, the calculation device  82  does not interrupt the charging process immediately but rather firstly waits to see whether the charging current I1 permanently or persistently exceeds the maximum current value of 32 A. By way of example, the calculation device  82  can integrate the measured current value Im over a predefined time window and then generate a control signal ST for switching the switch  85   a  to the off state only if the integral exceeds a predefined limit value. The type of evaluation of the measured current values Im and the procedure for generating the control signal ST for disconnecting the switch  85   a  are determined by the identifier-specific tripping criterion (or the identifier-specific tripping criteria) I32A. The tripping criterion I32A can contain limit values, such as maximum current values or maximum integral values, for example, and calculation instructions which are to be applied to the measured values Im in order to come to a decision about the continuation or the termination of the charging process. The term tripping criterion is therefore intended to be understood in the widest sense thereof. 
         [0041]    If, when the tripping criterion I32A are applied to the measured current values Im, the calculation device  82  determines that the charging cable  30  is overloaded, then said calculation device will generate a control signal ST by which the switch  85   a  of the switching device  85  is opened and the charging process is interrupted. 
         [0042]    As can be seen from the above statements, the charging station  10  according to  FIG. 1  is distinguished in that the charging process can be monitored by a single overload protection device  80 , although the charging processes can be performed with different charging currents by using different load capacity identifiers K. This is possible because the overload protection device  80  is connected to the central feed line  70  and monitors the feed line  70  on the basis of the respective load capacity identifier K. 
         [0043]      FIG. 2  shows an arrangement having a charging station  10  in which the overload protection device  80  is directly connected to the charging connection  20  of the charging station  10 , with the result that the identifier conductor LK of the charging cable  30  can be connected to the overload protection device  80 . This makes it possible for the overload protection device  80  to read the load capacity identifier K directly from the charging cable  30  and to monitor the feed line  70  in a load-capacity-identifier-specific manner independently of the control device  50 . 
         [0044]    In contrast to the exemplary embodiment according to  FIG. 1 , the overload protection device  80  can thus monitor the feed line  70  while individually taking into account the load capacity of the charging cable  30 , without the control device  50  needing to be involved. Thus, even if the control device  50  is operating ineffectively or is completely defective, the overload protection device  80  can prevent too high a charging current I1 from being fed into the charging cable  30  since, in contrast to the embodiment according to  FIG. 1 , the overload protection device  80  according to  FIG. 2  is not dependent on the involvement of the control device  50  with regard to obtaining the load capacity identifier K. 
         [0045]      FIG. 3  shows an exemplary embodiment of an arrangement having a charging station  10  and an electric vehicle  40 , in the case of which arrangement the electric vehicle  40  is charged by a voltage source  100 . Thus, as soon as the charging cable  30  connects the electric vehicle  40  to the charging station  10 , a charging current I1 will flow from the voltage source  100  in the direction of the electric vehicle  40 . In this case, the charging process is monitored solely by the overload protection device  80 , which reads the load capacity identifier K specifying the load capacity of the charging cable  30  via the identifier conductor LK of the charging cable  30 . 
         [0046]    The calculation device  82  of the overload protection device  80  can therefore, as has been described in detail in connection with  FIG. 1 , monitor the charging current I1 and, in the event of an identifier-specific tripping criterion stored in the memory  83  being exceeded, open the switch  85   a  of the switching device  85  if the recorded measured current values Im are too high according to the identifier-specific tripping criterion or criteria and an overload of the charging cable occurs or is imminent. 
         [0047]      FIG. 4  shows an exemplary embodiment in which the charging cable  30  is a three-phase charging cable and comprises three current-conducting phase conductors L 1 ′, L 2 ′ and L 3 ′ and a return conductor N′. In addition to the four conductors mentioned, an identifier conductor LK, which enables a load capacity identifier K to be read, is present. 
         [0048]    The charging connection  20  of the charging station  10  is accordingly likewise configured for a three-phase connection. Thus,  FIG. 4  reveals that a three-phase feed line  70  is connected to the charging connection  20 , which three-phase feed line comprises three phase conductors L 1 , L 2  and L 3  and a return conductor N. The charging connection  20  is connected to a three-phase current or voltage source  110  via said three-phase feed line  70 , which current or voltage source feeds the charging current in the form of phase currents I1, I2 and I3 into the charging cable  30  and therefore the electric vehicle  40  via the three-phase feed line  70  and the charging connection  20  in an uncontrolled manner (or, alternatively, under the control of a control device—not shown in  FIG. 4 ). 
         [0049]    In contrast to the exemplary embodiments in  FIGS. 1 to 3 , the overload protection device  80  according to  FIG. 4  is likewise of three-phase design. It comprises three current measuring devices  81   a,    81   b  and  81   c  which are arranged in the phase conductors L 1 , L 2  and L 3  of the feed line  70 . The phase-specific measured current values Im1, 1m2 and 1m3 measured by the current measuring devices arrive at the calculation device  82  which evaluates said measured current values in a phase-specific manner. In this case, the calculation device  82  uses the load capacity identifier K which it obtains directly from the charging connection  20  or from the identifier conductor LK of the charging cable  30 . 
         [0050]    In the case of the exemplary embodiment according to  FIG. 4 , there is thus also a direct connection between the overload protection device  80  and the charging connection  20  in order to enable the load capacity identifier K to be read directly by the overload protection device  80  without mediation of other components of the charging station  10 . 
         [0051]    If, after reading the identifier-specific tripping criterion or criteria, the calculation device  82  determines that the measured phase-current values Im1, Im2 and/or Im3 are too high, then it will interrupt the charging process by either disconnecting only those phase conductors L 1 , L 2  and/or L 3  that are affected by the overload or, alternatively, interrupting the entire charging process by disconnecting all of the phase conductors L 1 , L 2  and L 3  even if only individual phase conductors are affected. 
         [0052]    In order to disconnect individual phase conductors or all of the phase conductors, the overload protection device  80  according to  FIG. 4  is equipped with a switching device  85  that comprises in total three switches  85   a,    85   b  and  85   c.  The three switches are in each case assigned to a phase conductor of the feed line  70  and enable phase-specific disconnection of the feed line  70 . 
         [0053]    The invention has been described in detail with particular reference to preferred embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention covered by the claims which may include the phrase “at least one of A, B and C” as an alternative expression that means one or more of A, B and C may be used, contrary to the holding in  Superguide v. DIRECTV,  69 USPQ2d 1865 (Fed. Cir. 2004).