Abstract:
An embodiment of the present invention relates to a wireless power supply apparatus, which has a power pickup core formed to wrap a corner of a power pickup cable to increase an inductive electromotive force induced in a power pickup unit, has a power feeding unit configured to transfer a magnetic flux by only a power feeding cable without a power feeding core, to reduce the enormous cost for materials required to fabricate the power feeding core and thus enhance the price competitiveness, and reduce the weight and volume thereof and thus simplify the installation thereof, and has the power pickup core configured to include a plurality of power pickup core members, to reduce the weight and volume of the power pickup unit and thus increase the operational efficiency of the vehicle under which the power pickup unit is mounted

Description:
TECHNICAL FIELD 
       [0001]    An embodiment of the present invention relates to a wireless power supply apparatus. 
       BACKGROUND ART 
       [0002]    The contents described in the part simply provide background information on the embodiments of the present invention but do not constitute the related art. 
         [0003]    In general, an electric vehicle refers to a vehicle that uses electricity as a power source for driving the vehicle, and in order to drive the electric vehicle, a battery mounted on the electric vehicle is charged so that the electric vehicle is driven by the charged electric power. However, when a person or a machine that assists charging directly connects a charging electric wire to the vehicle to electrically charge the vehicle, such process is inconvenient and a user may be electrically shocked in the process of connecting the electric wire to the electric vehicle while gripping a plug with a hand. In this way, the method of charging the battery of the electric vehicle by using the charging electric wire causes inconvenience and an electric shock to the user, studies and developments of wireless power supply apparatuses that may charge a battery of an electric vehicle wirelessly have recently been actively made. 
       DISCLOSURE 
     Technical Problem 
       [0004]    An embodiment of the present invention relates to a wireless power supply apparatus that may increase an inductive electromotive force induced in a power pickup unit, reduce core loss and increase power efficiency by forming a power pickup unit such that the power pickup core surrounds corners of a power pickup cable, may reduce enormous material costs consumed to manufacture the power pickup core by constituting a power feeding unit such that magnetic fluxes may be delivered only by a power feeding cable without using a power feeding core, thereby increasing price competitiveness, reducing weight and volume, and making it convenient to install the wireless power supply apparatus, and may increase driving efficiency of the vehicle, under which the power pickup unit is mounted, by constituting the power pickup unit such that the power pickup unit includes a plurality of power pickup cores and reducing the weight and volume of a power pickup unit. 
       Technical Solution 
       [0005]    According to an embodiment of the present invention, a wireless power supply apparatus for wirelessly supplying electric power to a vehicle may include: a power pickup cable including a pair of first members spaced apart from each other in a first direction and a pair of second members connecting opposite ends of the first members; and a power pickup core part including a pair of power pickup core disposed along a second direction that is perpendicular to the first direction to surround the pair of first members, respectively, and the power pickup core part may include a power pickup unit surrounding at least one connecting portion formed by the pair of first members and the pair of second members. 
         [0006]    Each of the power pickup cores includes a plurality of power pickup core members arranged in a row. 
         [0007]    The wireless power supply apparatus may further include: a power feeding unit spaced apart from a lower side of the power pickup unit to provide a magnetic flux to the power pickup unit. 
         [0008]    The power feeding unit may include a power feeding cable and delivers a magnetic flux without using a power feeding core. 
         [0009]    At least one of the power pickup core members may surround the corresponding first member, and the other of the power pickup core members may surround the connecting portion. 
         [0010]    The other of the power pickup core members may surround the corresponding first member and one end thereof may extend in the second direction to surround the connecting portion. 
         [0011]    The other of the power pickup core members may surround the connecting portion from the top. 
         [0012]    The other of the power pickup core members may extend from the top of the connecting portion. 
         [0013]    The other of the power pickup core members may surround at least one of sides of the connecting portion in the second direction. 
         [0014]    Each of the power pickup core members may include a holding end extending from at least one of directions that are perpendicular to an extension direction of the power pickup core member at opposite ends of the power pickup core member. 
         [0015]    The holding ends provided in the power pickup core members of the pair of power pickup cores may be spaced apart from each other by a predetermined distance. 
         [0016]    The power pickup core part may include a plurality of power pickup cables. 
         [0017]    The power feeding unit may include: a pair of power feeding core parts in which a plurality of bar-shaped power feeding cores are arranged in a predetermined direction and which are disposed in parallel to be spaced apart from each other by a predetermined width; and a feeding cable disposed in the power feeding core parts. 
         [0018]    The power feeding unit may include: a pair of power feeding core parts in which a plurality of bar-shaped power feeding cores are arranged in a predetermined direction and which are disposed in parallel to be spaced apart from each other by a predetermined width; and a feeding cable disposed in the power feeding core parts, and each of the power feeding cores may include a horizontal member disposed parallel to a plane formed by the power feeding core parts and a vertical member extending in a direction that is perpendicular to the horizontal member to have an L shape. 
         [0019]    [Advantageous Effects] 
         [0020]    According to an embodiment of the present invention, core loss may be reduced by forming the power pickup core such that the power pickup core surrounds the corners of the power pickup cable, and accordingly, an inductive electromotive force induced in the power pickup unit may be increased. 
         [0021]    Further, price competitiveness may be increased by reducing enormous material costs consumed to manufacture the power feeding core, and the wireless power supply apparatus may be conveniently installed by reducing the weight and volume of the wireless power supply apparatus. 
         [0022]    In addition, the driving efficiency of the vehicle, on which the power pickup unit is mounted, may be increased by reducing the weight and volume of the power pickup unit. 
     
    
     
       DESCRIPTION OF THE INVENTION 
         [0023]      FIG. 1  is a view illustrating a wireless power supply apparatus according to an embodiment of the present invention. 
           [0024]      FIG. 2  is a view illustrating a power feeding unit of the wireless power supply apparatus according to the embodiment of the present invention. 
           [0025]      FIG. 3  is a perspective view illustrating a power pickup unit of the wireless power supply apparatus according to the embodiment of the present invention. 
           [0026]      FIG. 4  is a perspective view illustrating a power pickup cable of the wireless power supply apparatus according to the embodiment of the present invention. 
           [0027]      FIG. 5  is a view illustrating power pickup core members of the wireless power supply apparatus according to the embodiment of the present invention in detail. 
           [0028]      FIG. 6  is a perspective view illustrating a power feeding cable of the wireless power supply apparatus according to the embodiment of the present invention. 
           [0029]      FIG. 7  is a perspective view illustrating the power feeding cable and the power pickup unit of the wireless power supply apparatus according to the embodiment of the present invention. 
           [0030]      FIG. 8  is a view for comparing a power pickup performance of the wireless power supply apparatus according to the embodiment of the present invention. 
           [0031]      FIG. 9  is a perspective view illustrating the power feeding unit and the power pickup unit including a power pickup core part having an integral cover, of the wireless power supply apparatus according to the embodiment of the present invention. 
           [0032]      FIG. 10  is a view for comparing power pickup performance when the power pickup core part of the wireless power supply apparatus according to the embodiment of the present invention has the integral cover. 
           [0033]      FIG. 11  is a perspective view illustrating a case in which the power feeding unit of the wireless power supply apparatus according to the embodiment of the present invention includes a power feeding core part having a bar type power feeding core. 
           [0034]      FIG. 12  is a perspective view illustrating a case in which the power feeding unit of the wireless power supply apparatus according to the embodiment of the present invention includes a power feeding core part including an L-shaped power feeding core. 
           [0035]      FIG. 13  is a view illustrating a C-shaped power feeding core part  15  in detail. 
       
    
    
     BEST MODE 
       [0036]    Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. 
         [0037]    With regard to the reference numerals for the elements of the drawings, it is noted that the same elements have the same reference numerals even though they are illustrated in different drawings. Further, in a description of the present invention, detailed descriptions of the known configurations and known functions may be omitted when they may make the essence of the present invention unclear. 
         [0038]    Further, in a description of the elements of the present invention, the terms such as first, second, A, B, (a), and (b) may be used. However, the terms are used to distinguish one element from another element, but do not limit the essence, the sequence, or order of the element. When it is described that one element is “connected” or “coupled” to another element, the first element may be directly connected to the second element, but the first element may be connected to the second element while a third element may be present between the first and second elements. 
         [0039]    In general, a wireless power supply apparatus uses a method in which magnetic fluxes are formed by supplying high frequency power and an inductive electromotive force generated by a change of the magnetic fluxes is used. 
         [0040]      FIGS. 1 and 2  are views illustrating a wireless power supply apparatus according to an embodiment of the present invention. The wireless power supply apparatus according to the embodiment of the present invention includes a power feeding unit  10  and a power pickup unit  20 . The power feeding unit  10  includes a power feeding cable  12  and a power feeding core part  14  including a plurality of power feeding core parts  15 , and accordingly, a large amount of a core material is consumed so that enormous manufacturing costs are necessary. 
         [0041]    Further, when the power pickup unit  20  including an E-shaped power pickup core  22  is mounted under a vehicle, the total weight of the vehicle considerably increases due to the weight of the power pickup unit  20 , decreasing a driving efficiency of the vehicle. 
         [0042]      FIG. 3  is a perspective view illustrating a power pickup unit  300  of the wireless power supply apparatus according to the embodiment of the present invention.  FIG. 4  is a perspective view illustrating a power pickup cable  320  of the wireless power supply apparatus according to the embodiment of the present invention.  FIG. 5  is a view illustrating power pickup core members  342  and  362  of the wireless power supply apparatus according to the embodiment of the present invention in detail.  FIG. 6  is a perspective view illustrating a power feeding cable  420  of the wireless power supply apparatus according to the embodiment of the present invention.  FIG. 7  is a perspective view illustrating the power feeding cable  420  and the power pickup unit  300  of the wireless power supply apparatus according to the embodiment of the present invention. 
         [0043]    Hereinafter, a configuration and an operation of the wireless power supply apparatus according to the embodiment of the present invention will be described with reference to  FIGS. 3 to 7 . 
         [0044]    The wireless power supply apparatus according to the embodiment of the present invention may include a power pickup unit  300  and a power feeding unit  400 . The power pickup unit  300  may include a power pickup core part  330  including a first power pickup core  340  and a second power pickup core  360  and a power pickup cable  320 , and the power feeding unit  400  may include a power feeding cable  420 . 
         [0045]    The power feeding unit  400  may be configured to receive high frequency power from an inverter (not illustrated) connected to the power feeding cable  420 , to generate magnetic fluxes, and to deliver the generated magnetic fluxes to the power pickup unit  300 , and may be installed on a mad surface (not illustrated) on which vehicles (not illustrated) travel, a railroad surface (not illustrated), or a parking/stopping area (not illustrated), but the present invention is not limited thereto. The feeding cable  420  may include a pair of longitudinal members  422  and  424  and a pair of transverse members  426  and  428 . The pair of longitudinal members  422  and  424  may be disposed along a line (not illustrated) on which the vehicle (not illustrated) travels to be spaced apart from each other by a predetermined distance in a direction (hereinafter, “a first direction”) that is perpendicular to a lengthwise direction (hereinafter, “a second direction”) of the line, and opposite ends of the pair of longitudinal members  422  and  424  may be connected to each other by the pair of transverse members  426  and  428 . Although it is described as an example that one power feeding cable  420  is disposed in a description of a configuration and an operation of the wireless power supply apparatus according to the embodiment of the present invention, this is a simple embodiment and a plurality of power feeding cables  420  may be disposed in consideration of the magnitude of electric power required by the wireless power supply apparatus, or the like, or the power feeding cable  420  may be a cable bundle in which a plurality of cables are wounded. Further, although it is described as an example that the cross-section of the feeding cable  420  is rectangular, it is a simple embodiment and the cross-section of the power feeding cable  420  may have various shapes, including a circle, an ellipse, and a polygon. 
         [0046]    The power feeding unit  400  provided in the wireless power supply apparatus according to the embodiment of the present invention include a power feeding cable  420 , and is configured to generate magnetic fluxes without using a power feeding core and deliver the generated magnetic fluxes to the power pickup unit  300 . 
         [0047]    Referring to  FIG. 7 , the power pickup unit  300  may be disposed above the power feeding unit  400  to be magnetically coupled to the power feeding unit  400  while being spaced apart from the power feeding unit  400  by a predetermined interval. The power pickup unit  300  may be mounted under the vehicle (not illustrated) to be movable. In this case, the vehicle (not illustrated) that requires wireless supply of electric power may receive electric power while being stopped at an installation site of the power feeding unit  400 , and may continue to receive electric power even while the vehicle (not illustrated) is traveling. 
         [0048]    As illustrated in  FIG. 4 , the power pickup cable  320  may include a pair of first members  322  and  324  and a pair of second members  326  and  328 . The pair of first members  322  and  324  are spaced apart from each other in the first direction, and opposite ends of the pair of first members  322  and  324  may be connected to the pair of second members  326  and  328 . Connecting portions  323 ,  325 ,  327 , and  329  are formed between the first members  322  and  324  and the second members  326  and  328 . Although it is described as an example that the cross-section of the power pickup cable  320  is rectangular in a description of the configuration and operation of the wireless power supply apparatus according to the embodiment of the present invention, this is a simple embodiment and the cross-section of the power pickup cable  320  may have various shapes, including a circle, an ellipse, and a polygon. The number of disposed power pickup cables  320  may be suitably selected in consideration of the magnitude of electric power required by the wireless power supply apparatus and the size of the power pickup unit. When a plurality of power pickup cables  320  are provided, the power pickup cables  320  may be connected to each other in secures, in parallel, or in a combination form. 
         [0049]    As illustrated in  FIGS. 3 and 4 , the first power pickup core  340  and the second power pickup core  360  may surround the pair of first members  322  and  324 , respectively, and may be disposed along the second direction. The first power pickup core  340  may include a plurality of power pickup core members  342  arranged in a row. Further, the first pickup core  340  may include power pickup core members  346  and  348  surrounding at least one connecting portion  323  and  327  of the first member  322  and the second members  326  and  328 . Similarly, the second power pickup core  360  may include a plurality of power pickup core members  362  arranged in a row. Further, the second power pickup core  360  may include power pickup core members  366  and  368  surrounding at least one connecting portion  325  and  329  of the first member  324  and the second members  326  and  328 . 
         [0050]    As illustrated in  FIG. 5 , although the power pickup core members  342  and  346  may have a stapler-shape to surround the first members  322  and  324 , the present invention is not limited thereto but the power pickup core members  342  and  362  may have various shapes, including a C-shape according to occasions. The power pickup core members  342  and  362  may include holding ends  343  and  363  extending from opposite ends of the power pickup core members  342  and  362  in at least one of directions that is perpendicular to a direction in which the power pickup core members  342  and  362  extend. Although the holding ends  343  and  363  may function as supports or may contribute to formation of paths of magnetic fluxes passing through the power pickup core members  342  and  362  when the power core members  342  and  362  are arranged and disposed, the present invention is not limited thereto. Although not illustrated, the power pickup core members  346 ,  348 ,  366 , and  368  surrounding the connecting portions  323 ,  325 ,  327 , and  329  may also include holding ends  343  and  363 . Although it is described as an example that the cross-sections of the power pickup core members  342 ,  362 ,  346 ,  348 ,  366 , and  368  have a rectangular shape in a description of the configuration and operation of the wireless power supply apparatus according to the embodiment of the present invention, this is a simple embodiment, and the cross-sections of the power pickup core members  342 ,  362 ,  346 ,  348 ,  366 , and  368  may have various shapes, including a circle, an ellipse, and a polygon if necessary. Although the material of the power pickup core members  342 ,  362 ,  346 ,  348 ,  366 , and  368  may be ferrite that may easily form a magnetic field due to an electromagnetic induction phenomenon, the present invention is not limited thereto. 
         [0051]    Referring to  FIGS. 3 and 4 , the power pickup core members  346  and  348  may extend in the second direction to surround upper sides of the connecting portions  323  and  327  of the first member  322  and the second members  326  and  328 . Although the length by which the power pickup core members  346  and  348  extend in the second direction may be the same as the thickness or diameter of the second members  326  and  328 , the present invention is not limited thereto but the length of the extensions may be suitably selected if necessary. Similarly, the power pickup core members  366  and  368  may extend in the second direction to surround upper sides of the connecting portions  325  and  329  of the first member  324  and the second members  326  and  328 . Although the length by which the power pickup core members  366  and  368  extend in the second direction may be the same as the thickness or diameter of the second members  326  and  328 , the present invention is not limited thereto but the length of the extensions may be suitably selected if necessary. Although not illustrated, the power pickup core members  346 ,  348 ,  366 , and  368  may extend to surround a side surface of at least one connecting portions  323 ,  325 ,  327 , and  329  corresponding to the second direction. 
         [0052]    As described above, because the power feeding unit  400  of the wireless power supply apparatus delivers magnetic fluxes only with the power feeding cable  420  without using a power feeding core, price competitiveness may be increased by reducing enormous material costs consumed to manufacture a power feeding core and the wireless power supply apparatus may be simply installed by reducing the weight and volume thereof. 
         [0053]    Further, because the power pickup cores  340  and  360  include a plurality of power pickup core members  342 ,  346   348 ,  362 ,  366 , and  368 , the weight and volume of the power pickup cores  340  and  360  may be reduced as compared with an E-shaped power pickup core conventionally invented by KAIST so that it is expected that the driving efficiency of the vehicle, under which the power pickup unit is mounted, will be increased. 
         [0054]      FIG. 8  is a view for comparing a power pickup performance of the wireless power supply apparatus according to the embodiment of the present invention.  FIG. 9  is a perspective view illustrating the power feeding unit  400  and the power pickup unit  300  including a power pickup core part  330  having an integral cover, of the wireless power supply apparatus according to the embodiment of the present invention.  FIG. 10  is a view for comparing power pickup performance when the power pickup core part  300  of the wireless power supply apparatus according to the embodiment of the present invention has the integral cover. 
         [0055]    Hereinafter, the power pickup performance of the wireless power supply apparatus according to the embodiment of the present invention will be compared with reference to  FIGS. 7 to 10 . 
         [0056]    According to the experimental result, the voltage of the inductive electromotive force induced in the power pickup unit  300  of the wireless power supply apparatus of  FIG. 7  according to the embodiment of the present invention is 11.539 kV (a peak value) and was higher than the voltage of 8.37 kV (a peak value) of the inductive electromotive force induced in the power pickup unit  20  of the conventional wireless power supply apparatus of  FIG. 1 . As can be seen from the experimental result, the voltage of the electromotive force induced in the power pickup unit  300  of the wireless power supply apparatus according to the embodiment of the present invention increases to be higher than the voltage of the inductive electromotive force induced in the power pickup unit  20  of the conventional wireless power supply apparatus of  FIG. 1 . 
         [0057]    As illustrated in  FIG. 8 , the voltage of the inductive electromotive force included in the power pickup unit  80  that does not include the power pickup core members  346 ,  348 ,  366 , and  368  surrounding the connecting portions  323 ,  325 ,  327 , and  329  of the first members  322  and  324  and the second members  326  and  328  was 9.76 kV (a peak value). 
         [0058]    That is, as illustrated in  FIG. 7 , because the power pickup unit  300  includes the power pickup core members  346 ,  348 ,  366 , and  368  surrounding the connecting portions  323 ,  325 ,  327 , and  329  of the first members  322  and  324  and the second members  326  and  328 , it could be identified that induced electromotive force was increased as compared with the power pickup unit  80  of  FIG. 8  that does not include the power pickup core members  346 ,  348 ,  366 , and  368  surrounding the connecting portions  323 ,  325 ,  327 , and  329  of the first members  322  and  324  and the second members  326  and  328 . 
         [0059]    In the wireless power supply apparatus of  FIG. 9 , the power pickup unit  300  of the wireless power supply apparatus according to the embodiment of the present invention does not include the plurality of power pickup core members  342 ,  362 ,  346 ,  348 ,  366 , and  368  but includes first and second power feeding cores  340  and  360  integrally formed to surround the connection portions  323 ,  325 ,  327 , and  329  of the first members  322  and  324  and the second members  326  and  328 , and in this case, it can be seen that the voltage of the induced electromotive force included in the power pickup unit  300  is 11.540 kV (a peak value), and is higher than the voltage of 8.37 kV (a peak value) of the inductive electromotive force induced in the power pickup unit  20  of the conventional wireless power supply apparatus of  FIG. 1  and is slightly higher than the electromotive force of the case in which the power pickup unit includes the plurality of power pickup core members  342 ,  362 ,  346 ,  348 ,  366 , and  368  of  FIG. 7 . 
         [0060]    As illustrated in  FIG. 10 , the voltage of the electromotive force induced in the power pickup unit  100  that does not surround the connection portions  323 ,  325 ,  327 , and  329  of the first members  322  and  324  and the second members  326  and  328  was 10.137 kV (a peak value). That is, as illustrated in  FIG. 9 , it may be seen that because the power pickup unit  300  surrounds the connecting portions  323 ,  325 ,  327 , and  329  of the first members  322  and  324  and the second members  326  and  328 , induced electromotive force may be increased as compared with the case in which the power pickup unit  100  does not surround the connecting portions  323 ,  325 ,  327 , and  329  of the first members  322  and  324  and the second members  326  and  328  as illustrated in  FIG. 10 . 
         [0061]    As described above, it may be seen that the voltage induced in the power pickup unit of  FIG. 7  including a plurality of power pickup core members is substantially the same as the voltage induced in the integrally formed power pickup unit of  FIG. 9 . It can be seen that the voltage induced in the power pickup unit of  FIG. 7  is not different from the voltage induced in the power pickup unit of  FIG. 9  while the amount of the material consumed to form a core is remarkably reduced. This is an effect that may be obtained by forming the power pickup unit of the wireless power supply apparatus according to the embodiment of the present invention such that the power pickup unit surrounds the connecting portions of the first members and the second members. 
         [0062]      FIG. 11  is a perspective view illustrating a case in which the power feeding unit  400  of the wireless power supply apparatus according to the embodiment of the present invention includes a power feeding core part  1110  having a bar type power feeding core  1120 .  FIG. 12  is a perspective view illustrating a case in which the power feeding unit  400  of the wireless power supply apparatus according to the embodiment of the present invention includes a power feeding core part  1210  including an L-shaped power feeding core  1220 . 
         [0063]    As illustrated in  FIG. 11 , the power feeding unit  400  may include a power feeding core part  1110  including a plurality of pairs of bar-shaped power feeding cores  1120  arranged in a predetermined direction and disposed in parallel to each other to be spaced apart from each other by a predetermined width. Each of the bar-shaped power feeding cores  1120  has a bar shape having a predetermined length as a whole when viewed in the second direction. The bar-shaped power feeding cores  1120  are disposed in a direction that is parallel to the bottom of a mad surface (not illustrated), a railroad surface (not illustrated), or a parking/stopping area (not illustrated). As illustrated in  FIG. 11 , although it is described as an example that the cross-section of the bar-shaped power feeding cores  1120  is rectangular, this is a simple embodiment and the cross-section of the bar-shaped power feeding cores  1120  may have various shapes, including a circle, an ellipse, and a polygon. Although it is preferable that the material of the bar-shaped power feeding cores  1120  is ferrite that easily forms a magnetic field by an electromagnetic induction phenomenon, the present invention is not limited thereto. 
         [0064]    The power feeding cores having bar-shaped magnetic field forming parts form magnetic fields in a smaller range as compared with the E-shaped power feeding cores. This is because as the size of the structure of the magnetic field forming part is relatively small and the length is minimized such that a first lengthwise end and a second lengthwise end thereof, from which magnetic fields are mainly formed, are located close to each other, the spatial distance of the magnetic fields formed between the end and the second end becomes shorter. 
         [0065]    Because the bar-shaped power feeding cores  1120  may have a small volume and a simple structure as compared with the E-shaped power feeding cores, spatial efficiency may be increased and manufacturing costs may be reduced. Further, the above-described wireless power supply apparatus may efficiently supply electric power between the power feeding cores and the power pickup cores even though the distance between the power feeding cores and the power pickup cores is relatively far. 
         [0066]    Further, as illustrated in  FIG. 12 , the power feeding unit  400  may include a power feeding core part  1210  including a plurality of pairs of L-shaped power feeding cores  1220  arranged in a predetermined direction and disposed in parallel to be spaced apart from each other by a predetermined width. Each of the L-shaped power feeding cores includes a horizontal member  1222  disposed parallel to the bottom of road surface (not illustrated), a railroad surface (not illustrated), or a parking/stopping area (not illustrated) and a vertical member  1224  extending in a direction that is perpendicular to one end of the horizontal member  1222  to have an L shape. Although it is preferable that the length of the horizontal members  1222  is larger than the length of the vertical members  1224  and the vertical members  1224  are located at widthwise peripheries of the L-shaped power feeding cores  1120 , the present invention is not limited thereto. As illustrated in  FIG. 12 , although it is described as an example that the cross-section of the L-shaped power feeding cores  1220  is rectangular, this is a simple embodiment and the cross-section of the L-shaped power feeding cores  1220  may have various shapes, including a circle, an ellipse, and a polygon if necessary. Although the material of the L-shaped power feeding cores  1220  may be ferrite that may easily form a magnetic field due to an electromagnetic induction phenomenon, the present invention is not limited thereto. Further, although it is preferable that the feeding cable  420  is located above the horizontal members  1222  and is disposed adjacent to the vertical members  1224 , the present invention is not limited thereto. 
         [0067]    The L-shaped power feeding cores  1220  have a shorter magnetic path length as compared with the bar-shaped power feeding cores  11 . The magnetic fluxes of the magnetic field formed in the small range are damped to a small degree. It is because the magnetic flux is damped in a larger range as the MPL becomes larger. The magnetic fluxes of the power feeding cores of the wireless power supply apparatus according to the embodiment of the present invention are damped in a small range, loss of the cores may be reduced during wireless feeding and a relatively high induced voltage may be obtained as compared with the wireless power supply apparatus of another structure. 
         [0068]    Because the L-shaped power feeding cores  1220  have a relatively simple structure, they may be easily manufactured and manufacturing costs may be saved, and in particular, because the volume of the power feeding cores is small, the entire wireless power supply apparatus is spatially restricted in a small range. 
         [0069]      FIG. 13  is a view illustrating a C-shaped power feeding core part  15  in detail. 
         [0070]    A pair of power feeding core parts  15  in which a plurality of C-shaped magnetic forming parts  130  are arranged in a predetermined direction and which are disposed in parallel to be spaced apart from each other by a predetermined width is provided, and the pair of power feeding part generates a magnetic field, a direction of which changes periodically as a phase of received AC power changes. Here, each of the magnetic field forming parts has a semi-cylindrical shape including a first section  131  and a second section  132  obtained by cutting a cylinder in a radial direction thereof, a magnetic field, a direction of which changes between the first section  131  and the second section  132  as the phase of the AC power supplied changes is generated, and a least a portion of the magnetic field is formed between the first section  131 , and the body of the magnetic field forming part  130  and the second section  132 . 
         [0071]    The range of the magnetic fields formed by the power feeding core part in which the C-shaped magnetic field forming parts  130  of the present invention are arranged is small as compared with the power feeding core part of another form. This is because the size of the structure of the magnetic field forming part  130  is relatively small and the spatial distance of the magnetic field formed between the first section  131  and the second section  132  becomes shorter as the first section  131  and the second section  132  in which the magnetic fields are mainly formed is located close to each other. 
         [0072]    The magnetic flux of the magnetic field formed in the small range is damped in a small range. This is because the magnetic flux may be damped in a larger range as the spatial distance of the magnetic field becomes larger. Because the magnetic flux of the power feeding core part of the present invention is damped in a small range, power loss may be reduced during wireless feeding and an electromotive force of a relatively high current and a relatively high voltage may be obtained as compared with the wireless power supply apparatus of another structure. Further, because the power feeding core parts of the present invention have a simple structure as compared with the power feeding cores of another structure, they may be easily manufactured and manufacturing costs may be saved, and in particular, because the volume of the power feeding core parts is small, the entire wireless power supply apparatus is spatially restricted in a smaller range. Further, because a range of the magnetic field according to the present invention is small as a whole, a harmful influence on a human body due to an EMF, a breakdown or a malfunction of an electronic device may be reduced by reducing a range of the EMF. 
         [0073]    In this way, an magnetic path length (MPL) may be reduced by using the bar-shaped, the L-shaped, or the C-shaped power feeding cores of  FIGS. 11 to 13  in the power feeding core parts  15 , and thus core loss may be reduced. 
         [0074]    Even though it has been described until now that all the elements constituting the embodiments of the present invention are coupled into one or coupled to each other to be operated, the present invention is not necessarily limited to the embodiments. That is, without departing from the purpose range of the present invention, all the elements may be selectively coupled into one or more to be operated. 
         [0075]    The above description is a simple example of the technical spirit of the present invention, and the present invention may be variously corrected and modified by those skilled in the art to which the present invention pertains without departing from the characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are provided not to limit but to explain the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by the embodiments. The scope of the present invention should be construed by the claims and all the equivalent technical spirits should be construed to be included in the scope of the present invention. 
       DESCRIPTION OF REFERENCE NUMERALS 
       [0000]    
       
         
           
               130 : Magnetic field forming part 
               131 : First section 
               132 : Second section 
               15 : C-shaped power feeding core 
               300 : Power pickup unit 
               320 : Power pickup cable 
               330 : Power pickup core part 
               340 : First power pickup core 
               360 : Second power pickup core 
               342 ,  362 : Power pickup core member 
               400 : Power feeding unit 
               420 : Power feeding cable 
               1110 ,  1210 : Power feeding core part 
               1120 : Bar-shaped power feeding core 
               1220 : L-shaped power feeding core 
           
         
       
     
       CROSS-REFERENCE TO RELATED APPLICATION 
       [0091]    This application claims priority to Korean Patent Application No. 10-2014-0109235, filed on Aug. 21, 2014, the contents of which are hereby incorporated by reference in their entireties according to 35 U.S.C 119(a). The patent application also may be incorporated by reference in their entireties in nations other than the United States of America.