Tiled wireless charging coil solution for extended active area

Abstract

The disclosure generally relates to as method and apparatus for wireless charging station. In one embodiment, the disclosure provides an overlapping (or tiled) layout of a plurality of coils. Each coil may have a symmetric or an asymmetric turn layout. The disclosure also provides, design optimization techniques configured to determine the optimal tile overlap distance and/or coil, size to provide a substantially uniform electro-magnetic field over the surface of the wireless charging station.

What is claimed is: 
     
         1 . A transmitter charging station, comprising:
 a first coil having a first layout geometry to provide a first resonant magnetic field;   a second coil having a second layout geometry to provide a second resonant magnetic field, the second coil overlapping the first coil such that a combination of the first and the second magnetic fields provides a substantially uniform magnetic field above an overlapping plane of the first and the second coils.   
     
     
         2 . The charging station of  claim 1 , wherein the first coil and the second coils are arranged as partially overlapping tiles. 
     
     
         3 . The charging station of  claim 1 , wherein the first coil and the second coils are connected in series. 
     
     
         4 . The charging station of  claim 1 , wherein at least one of the first coil or the second coil defines an asymmetric or skewed coil turns. 
     
     
         5 . The charging station of  claim 1 , further comprising a third coil having a third layout geometry. 
     
     
         6 . The charging station of  claim 4 , wherein the third coil at least partially overlaps the second coil to extend the magnetic field of the first and tie second coil. 
     
     
         7 . The charging station of  claim 1 , wherein the second coil overlaps the first coil in a range of about 10-50% of a length of one of the first or the second coils. 
     
     
         8 . The charging station of  claim 1 , wherein an outer-most turn of the first coil extends beyond the inner most turn of the second coil. 
     
     
         9 . The charging station of  claim 1 , wherein the first coil defines a symmetric geometry and the second coil defines an asymmetric geometry. 
     
     
         10 . A wireless charging station, comprising:
 a first cod having a first resonance frequency tuner;   a second roil having a second resonance frequency tuner;   a capacitor connecting the first and the second coils;   a power source connected to the first coil and the second coil; and   a controller to configure at least one of the first Or the second frequency tuners to provide substantially similar resonance frequency from each of the first and the second coils.   
     
     
         11 . The wireless charging station of  claim 10 , wherein at least one of the first coil or the second coil defines an asymmetric or skewed coil turns. 
     
     
         12 . The wireless charging station of  claim 10 , wherein the first and the second coils are connected in series. 
     
     
         13 . The wireless charging station of  claim 10 , wherein the first coil is positioned to overlap the second coil. 
     
     
         14 . The wireless charging station of  claim 13 , further comprising a third coil wherein the third coil overlaps one or more of the first or the second coils. 
     
     
         15 . The wireless charging station of  claim 10 , wherein an outer most turn of the first coil extends beyond the inner most turn of the second coil. 
     
     
         16 . The wireless charging station of  claim 10 , wherein the first coil defines a symmetric geometry and the second roil defines an asymmetric geometry. 
     
     
         17 . A method to provide a substantially uniform magnetic field over a power transmission unit (PTU), the method comprising:
 forming a first coil to provide a first resonance frequency;   forming a second coil to provide a second resonance frequency;   tuning one or more of the first coil or the second coil to provide, substantially similar resonance frequencies;   overlapping first and the second coils to provide a substantially uniform magnetic field over the first and the second coils.   
     
     
         18 . The method of  claim 17 , wherein the first coil has a multi-sided layout in which at least one side is curved outwardly. 
     
     
         19 . The method of  claim 17  further comprising connecting the first and the second coils in series. 
     
     
         20 . The method of  claim 17 , further comprising interposing a tuning capacitor between the first and the second coils. 
     
     
         21 . The method of  claim 17 , further comprising determining an overlap distance as a function of a combined magnetic field strength of the first coil and the second coil at the overlap region. 
     
     
         22 . The method of  claim 17 , further comprising tuning the first resonance frequency of the first coil by tuning the capacitance of at least one capacitor associated with the first coil. 
     
     
         23 . The method of  claim 20 , further comprising tuning, a first capacitor associated with the first coil and a second capacitor associated with the second coil such that the tuning capacitor has substantially same value as either the first or the second capacitors. 
     
     
         24 . The method of  claim 23 , further comprising connecting the first capacitor, second capacitor and the tuning capacitor in series. 
     
     
         25 . The method of  claim 17 , further comprising a power receiving unit (PRU) proximally exposed to the substantially uniform magnetic field to thereby an receive electrical field charge from the PTU.