Power receiving apparatus, power transmission system, charging apparatus and power transmission method

Abstract

A power receiving apparatus includes: a resonance element having a specific resonance frequency and adapted to couple in a non-contacting relationship to a different resonance element through a resonance relationship; a rectification section configured to rectify ac current of the resonance frequency in response to energy received by the resonance element; and a switching section configured to cut off a supplying path of the ac current from the resonance element to the rectification section; the resonance element maintaining the coupling state through the resonance relationship to the different resonance element also when the supplying path of the ac current to the rectification section is blocked by the switching section.

1 . A power receiving apparatus, comprising:
 a resonance element having a specific resonance frequency and adapted to couple in a non-contacting relationship to a different resonance element through a resonance relationship;   rectification means for rectifying alternating current of the resonance frequency in response to energy received by said resonance element; and   switching means for cutting off a supplying path of the alternating current from said resonance element to said rectification means;   said resonance element maintaining the coupling state through the resonance relationship to the different resonance element also when the supplying path of the alternating current to said rectification means is blocked by said switching means.   
     
     
         2 . The power receiving apparatus according to  claim 1 , wherein said resonance element holds a current path in the form of a loop to maintain the coupling state through the resonance relationship to the different resonance element. 
     
     
         3 . The power receiving apparatus according to  claim 1 , further comprising an excitation element adapted to couple to said resonance element through electromagnetic induction;
 induction current which flows to said excitation element through the electromagnetic induction coupling between said resonance element and said excitation element being supplied to and rectified by said rectification means;   said switching means being provided at a position at which said switching means carries out cutoff control of a supplying path of the induction current from said excitation element to said rectification means.   
     
     
         4 . The power receiving apparatus according to  claim 1 , wherein said switching means is controlled to switch in response to a manual operation by a user. 
     
     
         5 . The power receiving apparatus according to  claim 1 , further comprising:
 a load adapted to receive direct current obtained by the rectification by said rectification means as power supply current thereto;   instruction inputting means for inputting an instruction regarding whether or not said load should be rendered operative; and   means for controlling said switching means to a state in which said switching means cuts off supply of current through said supplying path to said rectification means in response to the instruction input received through said instruction inputting means for rendering said load inoperative.   
     
     
         6 . The power receiving apparatus according to  claim 1 , further comprising:
 a rechargeable battery;   a charging circuit adapted to charge said battery with direct current obtained by the rectification by said rectification means;   detection means for detecting that said battery is charged up; and   means for controlling said switching means to a state in which said switching means cuts off supply of current through said supplying path to said rectification means when said detection means detects that said battery is charged up.   
     
     
         7 . The power receiving apparatus according to  claim 1 , further comprising radio communication means;
 said switching means being controlled to switch based on instruction information received by said communication means.   
     
     
         8 . A power transmission system, comprising:
 a power transmitting apparatus; and   a plurality of power receiving apparatus;   said power transmitting apparatus including
 a first resonance element having a specific resonance frequency and adapted to couple in a non-contacting relationship to a different resonance element through a resonance relationship, and 
 frequency signal generation means for supplying alternating current of the resonance frequency to said first resonance element, 
   each of said plurality of power receiving apparatus including
 a second resonance element having the resonance frequency and adapted to couple in a non-contacting relationship to a different resonance element through a resonance relationship, and 
 rectification means for rectifying alternating current of the resonance frequency in accordance with energy received by said second resonance element, 
   at least one of said plurality of power receiving apparatus further including switching means for cutting off supply of the alternating current from said second resonance element to said rectification means, said second resonance element maintaining a state wherein said second resonance element couples to the different resonance element through the resonance relationship also when the supplying path of the alternating current to said rectification means is cut off by said switching means,   said second resonance element of the power receiving apparatus in which said switching means is controlled to the state wherein said switching means cuts off the supplying path being coupled to said first resonance element of said power transmitting apparatus or said second resonance element of a different one of said power receiving apparatus through a resonance relationship and also to said second resonance element of another different one of said power receiving apparatus through a resonance relationship to carry out repeating of transmission of the power from said power transmitting apparatus.   
     
     
         9 . The power transmission system according to  claim 8 , wherein each of said power receiving apparatus further includes an excitation element for coupling to said second resonance element through electromagnetic induction;
 induction current which flows to said excitation element by the electromagnetic induction coupling between said second resonance element and said excitation element being supplied to and rectified by said rectification means, said switching means being provided at a position at which said switching means cuts off supply of the induction current from said excitation element to said rectification means.   
     
     
         10 . A charging apparatus for charging a rechargeable battery of a power receiving apparatus which includes a first resonance element having a specific resonance frequency and adapted to couple in a non-contacting relationship to a different resonance element through a resonance relationship, rectification means for rectifying alternating current of the resonance frequency in response to energy received by the first resonance element, switching means for cutting off supply of the alternating current from the first resonance element to the rectification means, the rechargeable battery, and a charging circuit adapted to charge the battery with direct current obtained by the rectification by the rectification means, the first resonance element maintaining a state wherein the first resonance element couples to the different resonance element through the resonance relationship also when the supplying path of the alternating current to the rectification means is cut off by the switching means,
 said charging apparatus comprising:   a second resonance element having a particular resonance frequency and adapted to couple in a non-contacting relationship to a different resonance element through a resonance relationship;   frequency signal generation means for supplying alternating current of the resonance frequency to said second resonance element; and   a mounting table capable of receiving a plurality of power receiving apparatus placed thereon such that said second resonance element is coupled to the first resonance elements of the power receiving apparatus placed on said mounting table through a resonance relationship.   
     
     
         11 . The charging apparatus according to  claim 10 , wherein the power receiving apparatus includes:
 detection means for detecting that the battery is charged up; and   means for controlling said switching means to cut off the supplying path when said detection means detects that the battery is charged up.   
     
     
         12 . The charging apparatus according to  claim 10 , further comprising:
 radio communication means for communicating with the power receiving apparatus by radio; and   means for producing information for controlling switching operation of the switching means of the power receiving apparatus based on information received from the power receiving apparatus by said radio communication means and supplying the produced information to the power receiving apparatus through said radio communication means to control switching operation of the switching means of the power receiving apparatus.   
     
     
         13 . The charging apparatus according to  claim 10 , wherein said mounting table has indications provided thereon for indicating recommendable mounting positions at which the power receiving apparatus should be placed. 
     
     
         14 . A power transmission method for a power transmission system which includes a power transmitting apparatus including a first resonance element having a specific resonance frequency and adapted to couple in a non-contacting relationship to a different resonance element through a resonance relationship and frequency signal generation means for supplying alternating current of the resonance frequency to the first resonance element, and a plurality of power receiving apparatus each including a second resonance element having the resonance frequency and adapted to couple in a non-contacting relationship to a different resonance element through a resonance relationship and rectification means for rectifying alternating current of the resonance frequency in accordance with energy received by the second resonance element, at least one of the power receiving apparatus further including switching means for cutting off supply of the alternating current from the second resonance element to the rectification means, the second resonance element maintaining a state wherein the second resonance element couples to the different resonance element through the resonance relationship also when the supplying path of the alternating current to said rectification means is cut off by the switching means,
 said power transmission method comprising the step of:   controlling the switching means to the state in which the switching means cuts off the supplying path to couple the second resonance element of the power receiving apparatus in which the supplying path is cut off by the switching means to the first resonance element of the power transmitting apparatus or the second resonance element of a different one of the power receiving apparatus through a resonance relationship and also to the second resonance element of another different one of the power receiving apparatus through a resonance relationship to carry out repeating of transmission of the power from the power transmitting apparatus.