Abstract:
A connecting apparatus for mounting on a vehicle or charging station, providing an electrical connection between the station and vehicle for charging an storage device of the vehicle, comprising: a contacting head for transferring electrical energy; at least one alignment device for coupling the contacting head to a receiver; a detector configured to determine a position of the receiver; and a control unit for aligning the contacting head and receiver; and wherein the alignment device includes a horizontal positioner; a pivoter for pivoting a contacting post carrying the contacting head from a parking position to a substantially vertical position; and a vertical positioner for telescoping the contacting post to adapt its length. The horizontal and vertical positioners, and pivoter performing an alignment movement independent from the others.

Description:
FIELD OF THE INVENTION 
     The present invention relates to charging systems for connecting electrically powered vehicles to a power feeding station to recharge an electrical energy storage device. 
     BACKGROUND OF THE INVENTION 
     Energy for electrically driven vehicles is usually stored in electrical energy storage devices, such as batteries or the like. The batteries need to be recharged regularly to ensure full operation of the electric vehicle. Privately used vehicles, such as cars, are usually operated to drive along a route once and their availability is restored after a sufficient time for recharging. 
     In contrast, vehicles for public transportation have a much longer operation time. Usually, the electrical energy stored in these vehicles does not provide sufficient capacity to operate public transportation vehicles, such as buses, over the entire operation time. Recharging stops, however, are not acceptable as the public transportation vehicle is filled with people to be commuted according to a bus schedule. 
     In order to keep the electrical energy storage device of such a vehicle as charged as possible, the brief bus stops for loading or unloading passengers can be used for connection to an electric power source in order to, at least partially, recharge the electrical energy storage device. 
     For electric buses, solutions found today are based on contacts through one or more divided pantographs or an arrangement of multiple pantographs on the roof of the vehicle or a division of a connecting bar on the wayside. 
     Furthermore, it would be inconvenient if the driver of the vehicle needed to manually establish a power connection each time the public transportation vehicle stops. 
     From document WO 2011/079 215 A2 a charging station for electric vehicles is known having connector braces to connect to contact plates or bars on the vehicle. The connector braces may have guiding strips with electrically conductive surfaces which converge such that the convergence is directed toward the electrically conductive surfaces. The alignment of the connector braces to the contact plates or bars on the vehicle is performed when the vehicle enters the charging station, so that the contact plates or bars move into the connector brace which is then aligned by means of the guiding strips. 
     Document WO 2011/064 596 A2 discloses an electric vehicle charging station having two pantographs arranged along the longitudinal axis of the vehicle to contact to power line bars when the vehicle is in position for recharging. 
     Document FR 2 802 069 discloses a charging station for an electric vehicle, such as a public bus, wherein an electrical connector to receive electrical power is arranged on the bus. The electrical connector is adapted to contact a corresponding connector on the charging station when the vehicle is in a position to connect the electrical connectors. However, this arrangement requires a relative positioning of the vehicle to the corresponding electrical connector on the charging station, which has to be assured by the driver of the vehicle by stopping the vehicle at a predefined position. 
     WO 2012/118422 A1 discloses an electrically powered bus with an arm on the rooftop. The pivotal arm is connected pivotable with a collector shoe at the end, which is in contact with the conductor line of a charging station during charging. The conductor line has positioning stops to guide by physical contact the collector shoe to the conductor line. The movement of the arm is a movement on a spherical surface. 
     US 2012111682A1 discloses a wayside mast with an electrically-supplying arm for charging a bus. The arm has a movable part, which permits to be displaced by pivoting upward if the current collector of the bus gets into physical contact with the movable part. The pivoting movement may be assisted by a motor which can be remote-controlled by a control device. 
     Hence, there is a need for a fully automatic connecting system for connecting an electrically driven vehicle to a charging station, wherein no active involvement of a driver or any mechanical guidance is required. Furthermore, the requirements for a stop on an exact stop position of the electrically driven vehicle should be low in order to keep the driver&#39;s focus on traffic events and the loading and unloading of passengers. 
     It is therefore an object of the present invention to provide an improved connecting system for establishing an electrical connection with an electrically driven vehicle at a charging station. Furthermore, it is an object of the present invention to ensure that the charging time at each stop of the electrically driven vehicle at a charging station is maximized by providing a quick connection and disconnection. 
     SUMMARY OF THE INVENTION 
     This object has been achieved by the connecting apparatus according to the invention, the vehicle, the charging station for an electrically driven vehicle, the charging system, and the method for connecting an electrically driven vehicle. 
     According to a first aspect, a connecting apparatus for mounting on a rooftop of a vehicle or at a charging station and for providing an electrical connection between the charging station and the vehicle for charging an electrical energy storage device of the vehicle is provided. The connecting apparatus comprises:
         a contacting head for connecting to contacting head receiving means for transferring electrical energy;   at least one alignment means for coupling the contacting head to the contacting head receiving means for electrically connecting to or disconnecting from the contacting head receiving means, respectively;   a detector means configured to determine a relative position of the contacting head receiving means to the contacting head; and   a control unit for controlling alignment between the contacting head and the contacting head receiving means in response to the determined position of the contacting head receiving means; and wherein the   at least one alignment means comprises a horizontal positioning means for laterally moving the contacting head in a horizontal direction;   a pivoting means for pivoting a contacting post carrying the contacting head at one end thereof from a parking position, in which the contacting post is substantially horizontal to a contacting position, in which the contacting post is elevated up to a substantially vertical position; and   a vertical positioning means for telescoping the contacting post across the horizontal direction to adapt the length of the contacting post and   wherein each of the horizontal positioning means, the pivoting means and the vertical positioning means performing an alignment movement and wherein each of the alignment movements being independent from the others.       

     One idea of the present invention is to provide a charging system for charging an electrically driven vehicle at a charging station. The electrically driven vehicle or the charging station is provided with a movable contacting head and an alignment unit to operate the contacting head, so that a connecting element of the connecting unit is aligned with and moved to a contacting head receiving means of the charging station or on the vehicle. The alignment unit uses means for detecting the position of the contacting head receiving means without the need of establishing a communication between the charging station and the vehicle. The provision of the alignment unit hence allows for omitting any additional effort of providing communication means between the charging station and the electrically driven vehicle, so that a simplified, quick and robust connection procedure without an exchange of any information can be provided. Providing individual alignment means for an individual alignment by a horizontal, vertical or pivotal movement of the contacting head provides a high flexibility for deviations of the vehicle parking position at charging stops. An automatic recognition of the charging infrastructure and state of the charging process without driver interaction is provided. 
     Furthermore, adjusting the position of the vehicle in relation to the contacting head receiving means of the charging station is facilitated by means of the alignment unit since the accuracy requirements to stop the vehicle at predetermined exact stopping positions are loosened. 
     Furthermore, the detector means may be configured to determine the position of the contacting head receiving means as an absolute position in relation to the location of the detector means or as a relative position in relation to the location of the contacting head. 
     It may be provided that the detector means comprises an optical detector. 
     The control unit may be coupled with a geo-positioning system to determine whether a charging station is approached, wherein the alignment unit is configured to activate at least one of the at least one positioning means to move the contacting head towards the contacting head receiving means. 
     According to an embodiment, the control unit may be coupled with a geo-positioning system to determine whether a charging station is approached, wherein the control unit is configured to activate at least one of the at least one alignment means in order to move the contacting head towards the contacting head receiving means. 
     According to a further aspect, a vehicle is provided which comprises the above connecting apparatus arranged on a vehicle body. 
     Furthermore, a geo-positioning system may be provided for providing a geographical position information about the geographical position of the vehicle, wherein the alignment unit is configured to determine by comparison with a provided set of charging station positions whether the vehicle approaches a charging station position and, if approaching a charging station position is detected, to activate the alignment unit, in particular to elevate the contacting head to an elevated position. 
     According to a further aspect, a vehicle comprising electrical driving means is provided. The vehicle comprises a contacting head receiving means having contacting surfaces for being contacted through a contacting head, wherein the contacting head receiving means has a longitudinal contacting rail with a U-shaped cross section. 
     Furthermore, the contacting surfaces may be arranged in the inner of the U-shaped cross section and extend substantially in parallel along the contacting rail. 
     An optical marker may be attached at the contacting head receiving means to allow an optical detector to determine the position of the contacting head receiving means. 
     Particularly, the optical marker may extend in the longitudinal direction of the contacting rail, wherein the optical marker includes two parallel recognizable stripes between which an opening of the U-shaped cross section is arranged. 
     According to a further aspect, a charging station for supplying electrical energy to a vehicle via a connecting apparatus is provided, wherein a contacting head receiving means is provided having contacting surfaces for contacting a contacting head; wherein the contacting head receiving means has a longitudinal contacting rail with an upside down U-shaped cross section. The contacting head receiving means is further provided with a first earth plate and a second earth plate and wherein the contacting surfaces, the first earth plate and the second earth plate are arranged in the inner of the U-shaped cross section and extend substantially in parallel along the contacting rail. A charging station with this contacting head receiving means configuration has the advantages that the earth connection is made first and disconnected last when coupling or decoupling. An earth resistance measurement may be configured to firstly check the quality (resistance) of the top earth connection and therefore the certainty that the contacting head is fully inserted into the contacting head receiving means. With above configuration a partial insertion or misalignment cannot lead to a situation where a power contact is connect to earth or that the power contacts are inverted. 
     Moreover, a supply unit may be comprised for detecting whether a contacting head of a vehicle is connected to the contacting head receiving means and for supplying electrical energy to the contacting head receiving means if the electrical connection to the contacting head is detected. 
     Moreover, in the inner of the U-shaped cross section contacting surfaces may be arranged and extend substantially in parallel along the contacting rail. 
     According to an embodiment, an optical marker may be attached to the contacting head receiving means to allow the optical detector to determine the position of the contacting head receiving means. 
     It may be provided that the optical marker extends in the longitudinal direction of the contacting rail, wherein the optical marker includes two parallel recognizable stripes between which an opening of the U-shaped cross section is arranged. 
     According to a further aspect, a charging station for supplying electrical energy to an electrically driven vehicle, wherein the charging station is provided with the above connecting apparatus. 
     Moreover, a supply unit may be provided for detecting whether the contacting head is connected to the contacting head receiving means and for supplying electrical energy to the contacting head if the electrical connection with the contacting head receiving means is detected. 
     According to a further aspect, a charging system comprises the above electrically driven vehicle and the above a charging station. 
     According to a further aspect, a method for charging an electrical energy storing device of a vehicle is provided, comprising the steps of:
         detecting the position of a contacting head receiving means; and   positioning a contacting head into the contacting head receiving means by   pivot positioning a contacting post which carries a contacting head at one end thereof from a parking position, in which the contacting post is substantially horizontal to a contacting position, in which the contacting post is elevated up to a substantially vertical position, thereafter   laterally and vertically positioning the contacting head for transferring electrical energy in response to the determined position of the contacting head receiving means.       

     The vertical positioning is performed by a means vertical positioning which telescopes the contacting post. The horizontal positioning is performed by a means horizontal positioning means and the vertical positioning is performed by a means vertical positioning means. 
     Furthermore, the detecting of the position of the contacting head receiving means is performed by recognizing a position of an optical marker at the contacting head receiving means using an optical detector. 
     It may be detected whether the contacting head is connected to the contacting head receiving means and wherein electrical energy is transferred to the electrical energy storing device if the electrical connection with the contacting head is detected. 
     According to an embodiment, it may be determined determine whether a charging station is approached, wherein at least one of the at least one alignment means is activated in order to move the contacting head towards the contacting head receiving means before the charging station has been reached. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention are described in more detail in the following description in conjunction with the accompanying drawings, in which: 
         FIG. 1  schematically shows a charging system with a charging station and an electrically driven vehicle; 
         FIG. 2  shows a connecting system being mounted on a rooftop of the electrically driven vehicle; 
         FIG. 3  shows a cross-sectional view through a feeding means of the charging station; and 
         FIG. 4  shows a cross-sectional view through a contacting head of a connecting arrangement. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a charging system  1  including a charging station  2  and a vehicle  3 , such as an electrically driven vehicle or a vehicle having electrical driving means, e.g. a bus for public transportation. The charging station  2  is located at one, several or all of the bus stops the electrically driven vehicle  3  is commuting to. In this way, an electrical connection between an electrical energy storage device  31  of the electrically driven vehicle  3  and the charging station  2  is established when the electrically driven vehicle  3  stops at the bus stop. 
     Before the electrically driven vehicle  3  leaves the bus stop, the electrical connection is disconnected and the electrically driven vehicle  3  is operated using the electrical energy stored in the electrical energy storage device  31 . 
     As the electrically driven vehicle  3  stops at the bus stop only for a few tens of seconds, such as 15 to 30 seconds, it is essential in this configuration that the electrical connection is established as soon as the electrically driven vehicle  3  stops at the bus stop and is disconnected just before the electrically driven vehicle  3  starts moving again in order to leave the bus stop. Furthermore, the establishing of the electrical connection requires that the electrically driven vehicle  3  stops at a fixed position to facilitate alignment of the contacts to be connected to one another. 
     In particular, the electrically driven vehicle  3  has a connecting arrangement  10  (connecting apparatus), shown in more detail in  FIG. 2 , which is attached to a rooftop  32  of the electrically driven vehicle  3  and is activated as soon as the electrically driven vehicle  3  approaches the charging station  2 . Approaching the charging station  2  can be detected using an automatic positioning detection system, such as GPS, GLONASS and the like, and by comparing, on the one hand, the detected geographical position and the odometer reading of the bus with, on the other hand, predetermined geographical positions of bus stops. 
     The connecting arrangement  10  has a horizontal positioning means  11  as an alignment means for adjusting the position of a contacting post  12  in a horizontal direction Q, which is substantially perpendicular to a longitudinal axis L of the electrically driven vehicle  3 . The movement of a contacting post  12  in a horizontal direction Q can be performed by a mechanical coupling e.g. with a thread rod  19  driven by the horizontal positioning means  11 . As an alternative embodiment a tooth belt can provided instead of the thread rod  19  to provide a mechanical coupling for moving the contacting post  12  in the horizontal direction Q. At its lower end, the contacting post  12  has an inner thread engaged with the thread rod, so that a rotation of the thread rod moves the contacting post  12  laterally. Other mechanical implementations for causing the horizontal movement of the contacting post  12  are possible as well. 
     At its opposite (upper) end, the contacting post  12  carries a contacting head  13  which is adapted to establish connections to a contacting head receiving means  20  of the charging station  2 . 
     Furthermore, the connecting arrangement  10  can comprise a horizontal pivoting means  14  and/or a vertical positioning means  15  as alignment means to adjust the vertical position of the contacting head  13 . The pivoting means  14  allows for pivoting the contacting post  12  from a parking position, in which the contacting post  12  is substantially horizontal, i. e. in parallel to the plane of the rooftop  32 , to a contacting position, in which the contacting post  12  is elevated up to a substantially vertical position. The mechanical implementation can make use of any means which are capable of lifting the contacting post  12 , thus pivoting it around the thread rod  19 . 
     The vertical positioning means  15  may allow for adapting the height of the contacting post  12  by telescoping. The contacting post  12  may include two or more telescoping elements configured to slide into each other, so that the length of the contacting post  12  can be controlled and the vertical position of the contacting head  13  (distance from the thread rod  19 ) can be set. 
     In general, the horizontal positioning means  11  and the first and second vertical alignment means  14 ,  15  can be actuated by individual means of an electrical, pneumatic, or hydraulic actuators, respectively. This gives a high flexibility to adjust the contacting head to the charging infrastructure in particular for buses which perform a kneeling movement before passengers entering or leaving the bus and to provide a coarse approach of the contacting head if approaching the charging point. 
     Furthermore, a control unit  16  is provided which is in contact with the horizontal positioning means  11  and the pivoting and vertical positioning means  14 ,  15  to control the movement and alignment of the contacting head  13 . Moreover, the control unit  16  may be configured to detect an absolute position of the contacting head receiving means  20  which provides electrical energy supplied by the charging station for recharging the electrical energy storage device  31  of the electrically driven vehicle  3 . The control unit  16  may be further configured to detect the relative position of the contacting head receiving means  20  in relation to the position of the contacting head  13 . Once the control unit  16  has detected the absolute or relative position, the control unit  16  controls the horizontal positioning means  11  and the pivoting and vertical positioning means  14 ,  15  so that the contacting head  13  is moved horizontally and vertically into the contacting head receiving means  20 . 
     The contacting head receiving means  20  substantially includes a contacting rail  21  extending into the longitudinal direction L. As shown in  FIG. 3 , the contacting rail  21  has a cross section of an upside down U-shape. The U-shaped contacting rail  21  has a base portion  22 , a first leg portion  23  and a second leg portion  24 . At the ends of the first and second leg portions  23 ,  24  and opposite to the base portion  22 , first and second extensions  25 ,  26  are provided which extend laterally away from one another, i.e. substantially in parallel to the base portion  22 . 
     The inner surface of the contacting rail  21  is provided with contacting surfaces  27 ,  28 . In the shown embodiment, a first contacting plate  27  is provided at an inner side of the first leg portion  23  and a second contacting plate  28  is provided at an inner side of the base portion  22  of the contacting rail  21 . Also provided at the inner side of the base portion  22  of the contacting rail  21  and adjacent to as well as extending substantially in parallel to the second contacting plate  28 , a first earth plate  29   a  is provided. At the inner side of the second leg portion  24 , a second earth plate  29   b  is provided. The first contacting plate  27  and the second contacting plate  28 , the first earth plate  29   a  and the second earth plate  29   b  substantially extend in parallel to the extension of the contacting rail  21 . This allows for the contacting head  13  to contact the contacting surfaces  27 ,  28 , and the contacting plates  29   a ,  29   b  at any position along the contacting rail  21 . 
     The contacting head  13  is constructed accordingly, as shown in  FIG. 4 . The contacting head  13  at the end of the contacting post  12  has a first side contact  41  and a second side contact  42  as well as a first earth contact  43   a  and a second earth contact  43   b , so that when the contacting head  13  enters the inner area of the U-shaped contacting rail  21 , the contacts  41 ,  42 ,  43   a ,  43   b  contact the first and second contacting surfaces  27 ,  28  and the first and second earth plates  29   a ,  29   b , respectively. 
     This configuration has the advantages that the earth connection is made first and disconnected last when coupling or decoupling. Furthermore, an earth resistance measurement may be configured to firstly check the quality (resistance) of the top earth connection and therefore the certainty that the head is fully inserted. With above configuration a partial insertion or misalignment can not lead to a situation where a power contact is connect to earth or that the power contacts are inverted. 
     According to another embodiment, instead of the upside down U-shaped contacting rail  12  the contacting rail could also be orientated so that it has a form similar to a C in cross section and connection to contacting rail  12  would occur horizontally, i.e. from the side. This might require a substantial L-shaped contacting rod where the contacting head extends laterally from the contacting rod. 
     The control unit  16  is capable of detecting an absolute position of the contacting rail  21  and/or a relative position of the contacting rail  21  with respect to the contacting head  13 . So, firstly a horizontal alignment of the contacting head  13  and subsequently a vertical alignment of the contacting head  13  can be carried out in order to insert the contacting head  13  into the U-shape of the contacting rail  21 , so that, as soon as the bus has stopped close to the charging station  2 , a connection between the electrically driven vehicle  3  and the charging station  2  can be established. 
     The control unit  16  may include an optical detector  17  as a detecting means which searches for a target element or pattern indicating the exact position of the contacting rail  21 . In the present embodiment, the target element may comprise two optically recognizable stripes  33 , such as fluorescent stripes, on the lower downwardly facing side of the extension  25 ,  26  of the contacting rail  21 , so that it can be recognized by the optical detector  17  arranged at the control unit  16  on the rooftop  32  of the electrically driven vehicle  3 . The two stripes  33  are detectable by the optical detector  17  and clearly indicate the position of the inner space of the U-shaped contacting rail  21  as the space between the stripes  33 , so that the contacting head  13  can easily be moved and positioned into the contacting rail  21 . 
     Apart from the control unit  16  using the optical detector  17 , other detector means can also be used which allow for detecting a position of the contacting head receiving means  20  and the contacting rail  21 . It is preferred that the positioning at the contacting rail  21  or the contacting head receiving means  20  is performed without any additional means, so that a robust and simple positioning system can be implemented. Other detecting means might include proximity sensors, radar sensors and the like. However, visually guided alignment means that are based on laser or a camera system are easy to implement as they only require optical markers at the contacting head receiving means  20 , if any. 
     The vehicle  3  can be equipped with a geo-positioning system  18  which provides geographical position information about the geographical position of the vehicle  3 . The control unit  16  can be configured to receive the geographical position information and to determine by comparison with a provided set of bus stop positions (charging station positions) whether the bus approaches a bus stop. If approaching a bus stop is detected, the control unit  16  can be activated and a lifting of the contacting head  13  to an elevated position between the rooftop  32  and the contacting head receiving means  20  can be commanded in order to shorten time for establishing a contact to the contacting head receiving means  20 . The geo-positioning system  18  can be included in the connecting apparatus as well. 
     On the side of the charging station  2 , a supply unit  51  is provided which controls the supply of charging power to the contacting rail  21 . 
     In order to trigger the supply unit  51  to supply the charging power, a test current may be passed from the electrically driven vehicle  3  through the first and second earth plates  29   a ,  29   b  functioning as earth contacts, and which are interconnected in the charging station  2 , and the current and voltage drops of the bridged earth contacts are measured to give the contact resistance. The test current is also sensed at the side of the charging station  2  to find out whether a connection at the contacting rail  21  is established. It may be provided that the supply of electrical power to the contacting rail  21  is activated only in case the test current is detected. 
     As soon as the contact resistance between the electrically driven vehicle  3  and the charging station  2  becomes too high, which is the case when the control unit  16  controls the horizontal positioning means  11  and/or the pivoting and vertical positioning means  14 ,  15  to remove the contacting head  13  from the contacting rail  21 , the charging process is stopped and the primary circuit is isolated. 
     According to another embodiment, a charging system may include a charging station and an electrically driven vehicle  3  where the connecting arrangement  10  with the above described configurations may be provided at the charging station and which serves to feed electricity to the vehicle, while the contacting rail  21  which may have the above described configurations, may be attached to the vehicle to be connected by the contacting head. The movement to align the contacting head towards the contacting head receiving means is then be carried out by the connecting apparatus mounted on the charging station. 
     According to a further embodiment also two connecting arrangements can be provided on the vehicle and the charging station which are moved towards each other to establish a connection. In this case one of the connecting arrangements is provided with a contacting rail instead of the contact head.