Power feed system

Abstract

Disclosed is a power feed system which can highly efficiently feed power to a power receiving unit from a power feed-side even though distance fluctuation or lateral shift occurs between a power feed-side helical coil and a power receiving-side helical coil. A distance measuring unit measures a inter-coil distance L 1 between the power feed-side helical coil and the power receiving-side helical coil, and a control units, adjust capacitances of a power feed-side varactor and a power receiving-side varactor in accordance with the inter-coil distance L 1 measured by the measuring unit.

1 . A power feed system, comprising:
 a power feed-side provided with a power feed-side loop antenna for receiving power, and a power feed-side coil electromagnetically coupled with the power feed-side loop antenna;   a power receiving unit provided with a power receiving-side coil electromagnetically resonated with the power feed-side coil, and a power receiving-side loop antenna electromagnetically coupled with the power receiving-side coil; and   a capacitor connected in parallel with at least one of the power feed-side coil and the power receiving-side coil, arranged variable in a capacitance thereof.   
     
     
         2 . The power feed system as claimed in  claim 1 , further comprising a distance measuring unit for measuring a distance between the power feed-side coil and the power receiving-side coil, and an adjusting unit for adjusting the capacitance of the capacitor in accordance with the distance measured by the distance measuring unit. 
     
     
         3 . The power feed system as claimed in  claim 1 , further comprising a reflection measuring unit for measuring a reflection from the power feed-side coil, and an adjusting unit for adjusting capacitance of the capacitor in accordance with the reflection amount measured by the reflection measuring unit. 
     
     
         4 . A power feed system, comprising:
 a power feed-side provided with a power feed-side loop antenna for receiving power, and a power feed-side coil electromagnetically coupled with the power feed-side loop antenna; and   a power receiving unit provided with a power receiving-side coil electromagnetically resonated with the power feed-side coil, and a power receiving-side loop antenna electromagnetically coupled with the power receiving-side coil,   wherein at least one of the power feed-side loop antenna and the power receiving-side loop antenna is divided into a plurality of members, and wherein the plurality of members being configured to move and change contact position relative to each other so as to vary a loop dimension thereof.   
     
     
         5 . The power feed system as claimed in  claim 4 , wherein the plurality of members is overlaid and contacted to each other so as to form a loop. 
     
     
         6 . The power feed system as claimed in  claim 4 , wherein at least one of the plurality of members includes at an end thereof a recess recessed in a middle direction, the recess being configured to slidably receive an end of an adjacent member of the plurality of members. 
     
     
         7 . The power feed system as claimed in  claim 4 , further comprising a moving unit for moving the plurality of members, a distance measuring unit for measuring distance between the power feed-side loop antenna and the power receiving-side loop antenna, and a moving unit control unit for controlling the moving unit to moving unit the plurality of members so that the loop dimension accords with the distance measured by the distance measuring unit. 
     
     
         8 . The power feed system as claimed in  claim 4 , further comprising a moving unit for moving the plurality of members, a reflection measuring unit for measuring a reflection from the power receiving-side coil, and a moving unit control unit for controlling the moving unit to move the plurality of members in accordance with the reflection amount measured by the reflection measuring unit. 
     
     
         9 . The power feed system as claimed in  claim 5 , further comprising a moving unit for moving the plurality of members, a distance measuring unit for measuring distance between the power feed-side loop antenna and the power receiving-side loop antenna, and a moving unit control unit for controlling the moving unit to moving unit the plurality of members so that the loop dimension accords with the distance measured by the distance measuring unit. 
     
     
         10 . The power feed system as claimed in  claim 6 , further comprising a moving unit for moving the plurality of members, a distance measuring unit for measuring distance between the power feed-side loop antenna and the power receiving-side loop antenna, and a moving unit control unit for controlling the moving unit to moving unit the plurality of members so that the loop dimension accords with the distance measured by the distance measuring unit. 
     
     
         11 . The power feed system as claimed in  claim 5 , further comprising a moving unit for moving the plurality of members, a reflection measuring unit for measuring a reflection from the power receiving-side coil, and a moving unit control unit for controlling the moving unit to move the plurality of members in accordance with the reflection amount measured by the reflection measuring unit. 
     
     
         12 . The power feed system as claimed in  claim 6 , further comprising a moving unit for moving the plurality of members, a reflection measuring unit for measuring a reflection from the power receiving-side coil, and a moving unit control unit for controlling the moving unit to move the plurality of members in accordance with the reflection amount measured by the reflection measuring unit.