Coupling Optimized Electrical Wireless Power Transmission

Abstract

In a first aspect of the current invention, a receiver circuit for a wireless power transmission link is proposed, wherein while maintaining substantially resonant coupling condition (resonance frequency of the transmitter unit is substantially equal to the resonance frequency of the receiver unit) the coupling is electronically controlled and optimized such that maximal critical coupling occurs.In a further aspect of the invention, the coupling between the transmitter unit and receiver unit is optimized by transforming of at least one receiver load such that maximal critical coupling occurs and overcritical coupling is avoided.In a further aspect of the invention, the coupling between the transmitter unit and receiver unit is optimized by transforming of at least one receiver load by means of boost- and/or buck converters such that maximal critical coupling occurs.

1 - 41 . (canceled) 
     
     
         42 . A method of coupling wireless power to a load comprising:
 receiving the wireless power in a first resonant circuit operable in a first mode and a second mode, wherein said first mode corresponds to a parallel resonant circuit and said second mode corresponds to a series resonant circuit;   transforming at least a part of said load of said first resonant circuit;   controlling mode switching between said first mode and said second mode and said load transformation by at least one of:   decreasing a quality of said first resonant circuit in said first mode and increasing the quality of said first resonant circuit in said second mode;   increasing the quality of said first resonant circuit in said first mode and decreasing the quality of said first resonant circuit in said second mode; and   increasing and decreasing the quality of said first resonant circuit in at least one of said first and second modes.   
     
     
         43 . The method according to  claim 42 , wherein said decreasing the quality of said first resonant circuit in said first mode and increasing the quality of said first resonant circuit in said second mode is established by a boost converter. 
     
     
         44 . The method according to  claim 42 , wherein said increasing the quality of said first resonant circuit in said first mode and decreasing the quality of said first resonant circuit in said second mode is established by a buck converter. 
     
     
         45 . The method according to  claim 42 , wherein said increasing and decreasing the quality of said first resonant circuit in at least one of said first and second modes is established by a combined buck-boost converter. 
     
     
         46 . The method according to  claim 42  further comprising;
 detecting at least one of: 
 a coupling condition of said first resonant circuit coupled with at least one second resonant circuit; 
 a voltage exceeding a desired target level across said load; and 
 a current exceeding a desired target level in said load. 
 
     
     
         47 . The method according to  claim 42  further comprising;
 decoupling said load from said first resonant circuit. 
 
     
     
         48 . The method according to  claim 47 , wherein said decoupling further comprises at least one of:
 opening a switch coupled in series between said first resonant circuit and said load, when said resonant circuit is in said second mode; and   closing a switch coupled in parallel to said first resonant circuit, when said resonant circuit is in said first mode.   
     
     
         49 . The method according to  claim 42  further comprising:
 calculating at least a part of said load of said first resonant circuit. 
 
     
     
         50 . The method according to  claim 42  further comprising at least one of:
 controlling the current in said load or the voltage across said load, wherein said controlling comprises at least one of said load transformation and switching between said first-and second modes, 
 optimizing coupling of said first resonant circuit coupled with at least one second resonant circuit, wherein said optimizing comprises at least one of said load transformation and switching between said first- and second modes, and 
 protecting from overcoupling of said first resonant circuit with said at least one second resonant circuit, wherein said protecting comprises at least one of said load transformation and switching between said first- and second modes. 
 
     
     
         51 . A wireless power receiver comprising:
 a first resonant circuit for receiving wireless power;   at least one first switch for switching said first resonant circuit between a first mode and a second mode responsive to a first control signal, wherein said first mode corresponds to a parallel resonant circuit and said second mode corresponds to a series resonant circuit;   at least one of a buck-, a boost- and a combined buck-boost converter responsive to a second control signal for transforming a load to said first resonant circuit; and   a controller for generating said first and second control signals when at least one of:
 a) said boost converter decreases a quality of said first resonant circuit in said first mode and increases the quality of said first resonant circuit in said second mode; 
 b) said buck converter increases the quality of said first resonant circuit in said first mode and decreases the quality of said first resonant circuit in said second mode; and 
 c) said combined buck-boost converter increases and decreases the quality of said first resonant circuit in at least one of said first and second modes. 
   
     
     
         52 . The receiver according to  claim 51 , further comprising:
 at least one second switch for decoupling said first resonant circuit from at least a part of said load in a third mode.   
     
     
         53 . The receiver according to  claim 52 , wherein said at least one second switch is coupled in series between said first resonant circuit and said load. 
     
     
         54 . The receiver according to  claim 52 , wherein said at least one second switch is coupled in parallel to said first resonant circuit. 
     
     
         55 . The receiver according to  claim 52 , wherein said at least one second switch for decoupling said first resonant circuit from at least a part of said load is part of at least one of said buck-, boost- and combined buck-boost converter. 
     
     
         56 . The receiver according to  claim 52 , further comprising:
 a timer for maintaining said first resonant circuit decoupled from said load for a predetermined time, wherein said at least one second switch couples said first resonant circuit with at least a part of said load when said predetermined time has elapsed.   
     
     
         57 . The receiver according to  claim 51 , wherein said receiver further comprises at least one of:
 a current- or voltage control loop for controlling a current in said load or a voltage across said load,   a coupling optimizer for strengthening a coupling of said first resonant circuit with at least one second resonant circuit,   an overcoupling detector for detecting a critical- or overcritical coupling condition of said first resonant circuit with said at least one second resonant circuit, and   an overvoltage detector for detecting an overvoltage condition across the load.   
     
     
         58 . The receiver according to  claim 57 , wherein said coupling condition is detected when more than one common pole appears in said first resonant circuit coupled with said at least one second resonant circuit. 
     
     
         59 . The receiver according to  claim 51 , further comprising a full wave rectifier used in at least one of said first and second modes. 
     
     
         60 . The receiver according to  claim 51 , wherein a clock of said controller is derived from a timing of a voltage of said first resonant circuit.