PATENT DOCUMENT

Publication Number: US-11228209-B1
Application Number: US-201816053228-A
Country: US
Kind Code: B1

Title: Wireless power transfer system and method

Abstract:
A wireless power transfer system comprising a transmitter and a receiver. The transmitter arranged to generate a varying electric field, and the receiver located in the varying electric field. The receiver comprising a first element and a second element. The first element and the second element having different geometries so different charge densities are induced on the first element and the second element by the varying electric field such that, in use, a current flows between the first element and second element, through a load connected between the first element and second element.

Claims:
The invention claimed is: 
     
       1. A wireless power transfer system comprising:
 a transmitter arranged to generate a varying electric field, 
 a receiver located in the varying electric field, 
 the receiver comprising a first element and a second element, 
 the first element and the second element having different three dimensional geometries governed by different Gaussian symmetries, so different charge densities are induced on the first element and the second element by the varying electric field such that, in use, a current flows between the first element and second element, through a load. 
 
     
     
       2. The system as claimed in  claim 1  wherein the first element is a three dimensional element having one or more planar surfaces and the second element is a rounded three dimensional element. 
     
     
       3. The system as claimed in  claim 2  wherein the first element is a plate and wherein the second element is one of a sphere, spheroid, ellipsoid, toroid, or cylindrical in shape. 
     
     
       4. The system as claimed in  claim 2  wherein the first element comprises a geometry that is governed by a Gaussian plate symmetry and the second element comprises a geometry that is governed by a Gaussian spherical symmetry. 
     
     
       5. The system as claimed in  claim 1  wherein a planar surface of the one or more planar surfaces of the first element is configured to be arranged substantially parallel to the planar conductive transmission element. 
     
     
       6. The system as claimed in  claim 1  wherein the transmitter and the receiver are separated by a transmission distance and the transmission distance is less than the point where the transmitter can be considered a point charge. 
     
     
       7. The system as claimed in  claim 1  wherein the first element and the second element are separated by a conduction distance and wherein the conduction distance is less than the point where the varying electric field has no effect on the second element and wherein the transmission distance and conductive distance are different to each other. 
     
     
       8. The system as claimed in  claim 1  comprising an alternating power source in electrical communication with the transmitter, the varying and wherein the alternating power source enriches and depletes the transmitter with charge, thereby creating the varying electric field. 
     
     
       9. The system as claimed in  claim 1  wherein work is performed by the alternating power source to generate the varying electric field and the load configured to harvest the work done by the alternating power source. 
     
     
       10. The system as claimed in  claim 1  wherein the varying electric field causing charge migration between the first element and second element due to the varying electric field having a different effect on the first element and the second element, and wherein the charge migration between the first and second element resulting in a current to flow through a load between the first element and the second element. 
     
     
       11. A wireless power receiver comprising:
 a first conductive element, a second conductive element, and a load electrically connected therebetween, 
 the first element and second element comprising different three dimensional geometries governed by different Gaussian symmetries as compared to each other such that different charge densities are induced thereon in the presence of a varying electric field, and; 
 a current flows between the first element and the second element through the load. 
 
     
     
       12. The receiver as claimed in  claim 11  wherein the first element is three dimensional planar element and the second element is a rounded three dimensional element. 
     
     
       13. The receiver as claimed in  claim 12  wherein the first element is a plate and the second element is one of a sphere, spheroid, ellipsoid, toroid or cylindrical in shape. 
     
     
       14. The receiver as claimed in  claim 12  wherein the first element comprises a shape that is governed by a Gaussian plate symmetry and the second element comprises a shape that governed a Gaussian spherical symmetry.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a wireless power transfer system, components thereof and method. More particularly, but not exclusively the invention relates to an electric field based wireless power transfer system, components thereof and method. 
     BACKGROUND TO THE INVENTION 
     Contactless or wireless power transfer systems are a known area of both established and developing technology. Wireless power transfer systems can take a number of different forms. The particular form is application dependent. Inductive and capacitive power transfer are the most commonly known used power transfer methodologies. 
     A basic inductive power transfer system comprises an AC power source, a primary coil, a secondary coil and a load. The AC power source is coupled to the primary coil. The primary coil is connected to the AC source forming a closed circuit. The AC source supplies a current to the primary coil which creates a magnetic field that radiates outwardly from the coil. The magnetic field is coupled to the secondary coil and induces a current in the secondary coil. The induced current is used to supply a load connected to the secondary coil. 
     A basic capacitive power transfer system comprises an AC power source, a first plate pair, a second plate pair and a load. The AC power source is coupled to a first plate the first plate pair creating an electric field. The electric field from the first plate induces a charge on the second plate of the first plate pair. Current flows from the second plate, through a load to a third plate of the second plate pair. The third plate becomes charged resulting in a second electric field that induces charge in the fourth plate of the second plate pair and current flows from the fourth plate back to the source, thus forming a complete circuit. 
     In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide for wireless power transfer system, components thereof or method that ameliorates or alleviate at least one disadvantage associated with the prior art, or at least provide a useful alternative to related art systems. 
     Disclosed is a wireless power transfer system, method and components thereof. In particular disclosed herein is an electric field based wireless power transfer system, method and components thereof. 
     According to one exemplary embodiment there is provided a wireless power transfer system comprising: a transmitter configured to create a varying electric field and a receiver within the varying electric field. The receiver in the varying electric field being separated from the transmitter and the receiver comprising a first element and a second element. The first element having a first geometry and the second element having a second different geometry to the first element. The electrical characteristics/behaviour of each element being different to each other when in the varying electric field, such that a current flows between the first element and second element when connected to a load due to interaction between the varying electrical field and the first element and the second element. 
     The transmitter comprises a plate, the receiver first element is a plate and the second element is a sphere (or other spheroid) 
     The first element is governed by Gaussian planar symmetry and the second element is governed by Gaussian spherical symmetry 
     The electric characteristic of each element being the polarization of each element in the presence of the varying electric field. 
     The varying electric field polarizing the first element of the receiver to a first level, the varying electric field polarizing the second element of the receiver to a second level, wherein the difference in polarization causes a current to flow between the first element and second element and through a load electrically connected between the first and second element. 
     The electric characteristic is electrical field effect from the varying electric field, wherein the first and second elements experience a different electrical field effect thereby causing a current to flow through a load connected between the first and second element. 
     In an embodiment each of the first and second elements experiences a different electrical field effect due to the different geometry of the first and second elements. 
     According to a further exemplary embodiment there is provided a wireless power transfer system comprising; a transmitter arranged to generate a varying electric field and a receiver located in the varying electric field. The receiver comprising a first element and a second element, the first element and the second element having different geometries so different charge densities are induced on the first element and the second element by the varying electric field such that, in use, a current flows between the first element and second element, through a load. 
     The transmitter comprises a planar conductive transmission element for generating a varying electric field. 
     The first element and the second element comprise three dimensional geometries that are different to each other. 
     The first element and second element are conductive elements. 
     The second element may function as a charge well to receive charges. In one form the second element may be configured to temporarily store charge received by the second element. 
     The first element comprises a planar surface. The preceding claims wherein the second element comprises a curved or rounded surface. 
     The first element is a three dimensional planar element and the second element is a rounded three dimensional element. 
     In one form the first element is a plate and the second element is one of a sphere, spheroid, ellipsoid, toroid, or cylindrical in shape. Do they have to be curved, or could they be for example inverted pyramid? Alternatively the first plate may comprise a three dimensional shape that includes a plurality of planar sides or surfaces. For example the first plate may comprise an inverted pyramid shape. 
     The second element is preferably hollow but alternatively the second element may be solid. 
     Preferably the first element is solid. Preferably the transmission element is solid. 
     The first element is a rectangular prism in shape (i.e. a rectangular plate), and the second element is a sphere or spherical in shape. 
     The first element comprises a geometry that functions as a Gaussian planar surface and the second element comprises a geometry that functions as a Gaussian curved surface. 
     Preferably the first element comprises a first Gaussian geometry and the second element comprises a second Gaussian geometry, wherein the first and second Gaussian geometries are different to each other. 
     In another form first element may be a three dimensional polygon with multiple planar faces such as for example the first element may be a pyramid shaped element or an octahedron or a hexahedron or any other three dimensional polygon with planar faces. In another form the second element may be any three dimensional shape that includes a continuous curved surface such as for example a sphere or a cylindrical prism. 
     In one form the first element comprises geometry (i.e. shape) that is governed by a Gaussian plate symmetry and the second element comprises a geometry (i.e. shape) that is governed by a Gaussian spherical symmetry. 
     The planar surface of the first element is substantially parallel to the planar conductive transmission element. 
     The transmitter and the receiver are separated by a transmission distance and the transmission distance is less than the point where the transmitter can be considered a point charge. 
     The first element and the second element are separated by a conduction distance, wherein the conduction distance is greater than or equal to zero and wherein the conduction distance is less than the point where the varying electric field has no effect on the second element. 
     In one form the transmission distance and conductive distance are different to each other. 
     In another form the transmission distance between the first and second elements and the transmission plate is the same. 
     In an embodiment the wireless power transfer system further comprises a load and a conductor, the conductor electrically coupling the first element and second element, the conductor further electrically coupled to the load, such that a current flows between the first element and second element through the conductor and the load. The receiver comprises the load and a conductor. The conductor electrically couples the first element and second element, the conductor further being electrically coupled to the load, such that a current flows between the first element and second element through the conductor and the load. The load is an electrical load and the electrical load disposed between the first element and the second element. 
     The load comprises a load element and an electrical circuit electrically coupled to the load element, wherein the circuit is configured for electrically transferring power to the load element and the load element is configured to consume power. 
     In an embodiment the load element is part of the receiver. In one example the load element may be a rechargeable power source such as a rechargeable battery. 
     The surface area of the transmitter is greater than or equal to the surface area of the first element of the receiver. 
     The surface area of the planar conductive transmission element is greater than or equal to the surface area of the planar surface of the first element. 
     The second element has a surface area that is greater than or equal to the surface area of the first element. 
     Alternatively the surface area of the second element may be less than or equal to the surface are of the first element. In one exemplary form if the second element is a hollow sphere or a hollow element, then the surface area may be less than the surface area of the first element when the first element is a plate. 
     Preferably the first element comprises a rectangular cross section. Alternatively the first element comprises a square cross section. 
     The second element comprises a circular cross section. Alternatively the second element comprises an elliptical cross section or an oval cross section. 
     In an embodiment the wireless power transfer system further comprises an alternating power source in electrical communication with the transmitter, the varying electric field being created due to an alternating current being supplied to the transmitter. The transmitter preferably comprises the alternating power source and the alternating power source is arranged to be in electronic communication with the transmission element. 
     In an embodiment the power supply comprises a plurality of switches, the transmission element connected downstream of a first switch and upstream of a second switch, the switches connecting to a positive and negative rail. 
     In an embodiment the switches are configured to control charging and discharging of the transmission element. 
     In an embodiment the first switch is closed and the second switch is open to charge the transmission element, and the first switch is open and the second switch is closed when to discharge the transmission element. 
     Additionally the power supply may comprise a controller configured to control the actuation of the switches based on a predetermined switching pattern to achieve a desired rate of charging and discharging of the transmission element. 
     The alternating power source enriches and depletes the transmitter with charge, thereby creating the varying electric field. 
     The wireless power transfer system wherein work is performed by the alternating power source to generate the varying electric field and the load configured to harvest the work done by the alternating power source. 
     The varying electric field causing charge migration between the first element and second element due to the varying electric field having a different effects on the first element and the second element, and wherein the charge migration between the first and second element resulting in a current to flow between the first element and the second element, and in use through a load. 
     In one exemplary implementation the electric field power transfer system may be used for charging or for powering portable devices or mobile devices or wearable devices or any other suitable electrical devices. For example the electric field transfers power from the transmission element to the receiver. The receiver is preferably installed as part of a device that requires power or requires charging. The transmission element may be part of a charging mat or a charging pod. 
     Alternatively the transmission element may be incorporated into a structure such as a floor or table or any other structure upon which a device can be rested. The power transferred from the transmission element can be used or consumed by the receiver to power the device or to charge a power source. Some exemplary uses of the electric field power transfer system may be to power a wearable device such as a chargeable earphones or a watch or a fitness tracker. Another exemplary use may be to charge mobile phones or tablets or laptops or other portable electronic devices. 
     According to an exemplary embodiment there is provided a receiver of a wireless power transfer system comprising; a first element and a second element. The first element and second element comprising different geometries as compared to each other such that different charge densities are induced thereon in the presence of a varying electric field, and, in use, a current flows between the first element and the second element through a load. 
     The first element and the second element are conductive elements. The first element and second element may be spaced apart. 
     The first element and the second element comprise three dimensional geometries (i.e. shapes) that are different to each other. 
     The first element comprises a geometry that functions as a Gaussian planar surface and the second element comprises a geometry that functions as a Gaussian curved surface. 
     Preferably the first element comprises a first Gaussian geometry and the second element comprises a second Gaussian geometry, wherein the first and second Gaussian geometries are different to each other. 
     In one form the first element comprises geometry (i.e. shape) that is governed by a Gaussian plate symmetry and the second element comprises a geometry (i.e. shape) that is governed by a Gaussian spherical symmetry 
     Preferably the first element comprises a planar surface. Preferably the second element comprises a curved or rounded surface. The second element is arranged or configured to function as a charge well. 
     In one form the first element is three dimensional planar element and the second element is a rounded three dimensional element. 
     Preferably the first element is a plate. The second element is one of a sphere, spheroid, ellipsoid, toroid or cylindrical in shape. Preferably the second element is a sphere. 
     Preferably the first element is solid and preferably the second element is hollow. Alternatively the second element is solid. 
     The first element preferably comprises a rectangular or square cross section. The second element comprises a circular cross section. 
     In an embodiment the receiver comprises load and a conductor, the conductor electrically coupling the first element and second element, the conductor further electrically coupled to the load such that a current flows between the first element and the second element through the conductor and the load. The load is an electrical load and the electrical load is disposed between the first element and the second element. The load comprises a load element and an electrical circuit electrically coupled to the load element, wherein the circuit is configured for electrically transferring power to load element and the load element is configured to consume power. 
     According to an exemplary embodiment there is provided a transmitter of a wireless power transfer system comprising: a conductive transmission element arranged to generate a varying electric field, in use, the transmitter configured to cause a current flow in a receiver positioned within the varying electric field, the receiver further having two elements having different geometries, and the current flow being caused by the varying electric field inducing different charge densities on the two elements. 
     The transmission element is a planar member or comprises one or more planar or flat surfaces. The transmission element is preferably a plate. 
     The transmission element comprises a rectangular or square cross section. 
     Preferably the transmission element is a solid member. Alternatively the transmission element may be a hollow member. 
     In an embodiment the transmitter further comprises an alternating power source, the alternating power source electrically coupled to the transmission element, the alternating power source charging and discharging the transmission element with an electrical charge. The charging and discharging of the transmission element with electrical charge creates a varying electric field. When the transmission element is enriched with electric charge an electric field is built that extends outwardly from the transmission element. When the charge from the transmission element is depleted (i.e. discharged), the electric field emanating from the transmission element reverses. Alternatively the electric field may dissipate because the power source is switched off i.e. no power is delivered to the transmitter. 
     In an embodiment the power supply comprises a plurality of switches, the transmission element connected downstream of a first switch and upstream of a second switch, the switches connecting to a positive and negative rail. 
     In an embodiment the switches are configured to control charging and discharging of the transmission element. 
     In an embodiment the first switch is closed and the second switch is open to charge the transmission element, and the first switch is open and the second switch is closed when to discharge the transmission element. 
     Additionally the power supply may comprise a controller configured to control the actuation of the switches based on a predetermined switching pattern to achieve a desired rate of charging and discharging of the transmission element. 
     According to an exemplary embodiment there is provided a wireless power transfer system comprising; a transmitter coupled to an alternating current/power source, the transmitter configured to generate a varying electric field a receiver positioned within the varying electric field, the receiver comprising a first element, a second element and a load element electrically connectable therebetween, wherein work is performed by the alternating current/power source to generate the varying electric field, and the load element harvesting the work done by the alternating current/power source. 
     The varying electric field has a first effect on the first element and a second effect on the second element, the first effect being different to the second effect. The first element and second element comprising different geometries as compared to each other. The varying electric field having a different effect on the first element and the second element due to their different geometries. 
     The varying electric field inducing different charge densities on the first element and the second element due to their differing geometries and, in use, causing a current to flow between the first element and the second element and through a load connectable therebetween. Energy is transferred from the transmitter to the receiver via the varying electric field. 
     In an embodiment of the wireless power transfer system, the first element, of the receiver, comprises a first geometry, the second element, of the receiver, comprises a second geometry, the first geometry being different to the second geometry in at least one aspect. The one aspect may be any one of surface area, a surface contour, cross section, cross sectional area, volume, density or overall three dimensional shape. 
     According to a further embodiment there is provided a wireless power transfer system comprising; a transmitter arranged to generate a varying electric field, a receiver positioned within the varying electric field, the receiver comprising a first element, a second element, the first element and second element being differently shaped such that the varying electric field causing charge migration between the first element and second element due to different effects of the varying electric field on the first element and the second element, the charge migration resulting in a current to flow between the first element and second element and through a load element that is connectable between the first and second element. 
     According to another embodiment there is provided a wireless power transfer system comprising; a transmitter arranged to generate a varying electric field, a receiver positioned within the varying electric field, the receiver comprising a first element and second element, the varying electric field causing the first element to switch polarity in response to the varying electric field, thereby causing a current to flow between the first element and the second element based on the switching polarity, and wherein the current flows in use when a load element is electrically coupled between the first and second elements. 
     The first element and second element comprise different geometries as compared to each other. The varying electric field causing a different effect on the first element and second element as compared to each other due to the different geometries. 
     According to yet another embodiment there is provided a wireless power transfer system comprising; a transmitter arranged to generate a varying electric field, a receiver positioned within the varying electric field, the receiver comprising a first element and a second element, a load element electrically connectable between the first and second elements, the first and second element having different geometries that are governed by different Gaussian symmetries to each other such that different charge densities are induced thereon (or causing charge migration between the first and second element due to the different Gaussian symmetries), such that a current flows between the first element and second element and through the load element. 
     According to an embodiment there is provided a wireless power transfer system comprising; a transmitter arranged to generate a varying electric field, a receiver positioned within the varying electric field, the receiver comprising a first element and a second element, a load element electrically connectable between the first and second elements, wherein the receiver is arranged in an open circuit and a current is induced to flow between the first element and second element and through the load element, the current flowing between the first element and second element due to the varying electric field acting on the first element and the second element. 
     According to an embodiment there is provided a wireless power transfer system comprising; a transmitter arranged to generate a varying electric field, a receiver positioned within the varying electric field, the receiver comprising a first planar element and a second curved/rounded element being spaced apart and electrically coupled together, and a load electrically connectable between the first planar element and the second curved/rounded element, the varying electric field having a different effect on the first planar element and the second curved/rounded element, thereby inducing a current to flow between the first planar element and the second curved/rounded element and through the load element. 
     The transmitter and receiver as described herein can be used with or in any embodiment of the wireless power transfer system. The transmitter and receiver as described herein form components of any of the wireless power transfer systems described herein. 
     According to a further embodiment there is provided a method for wirelessly transferring power from a transmitter to a receiver, the transmitter comprising a conductive transmission element, the receiver comprising a first element and a second element comprising the steps of: generating a varying electric field by a transmitter, inducing different charge densities on the first element and the second element when the receiver is disposed in the varying electric field, a current flowing between the first element and second element and through a load, due to the different charge densities being induced on the first element and the second element. 
     The different charge densities are induced on the first element and the second element because the first element and second element have different geometries when compared to each other. 
     The first element and second element comprise different geometries that are governed by Gaussian symmetry differentials when compared to each other. Preferably the first element comprises a geometry such that the first element is governed by a Gaussian plate symmetry. The second element comprises a geometry such that the second element is governed by a Gaussian sphere symmetry. The differing Gaussian symmetries of the first element and second element induce differing charge densities due to the individual effect on each element by the varying electric field. 
     According to a further embodiment there is provided a method for wirelessly transferring power from a transmitter to a receiver, the transmitter comprising a conductive transmission element, the receiver comprising a first element and a second element, and the first element and second element comprising different geometries such that there is a Gaussian symmetry differential between the first element and second element, the method comprising the steps of; generating a varying electric field by the transmitter, causing the first element to switch polarity in response to the varying electric field, thereby causing a current to flow between the first element and second element and through a load. 
     The term “comprising” as used in this specification means “consisting at least in part of”. When interpreting each statement in this specification that includes the term “comprising”, features other than that or those prefaced by the term may also be present. Related terms such as “comprise” and “comprises” are to be interpreted in the same manner. The term geometry denotes a shape or topology. The terms geometry, topology and shape can be interchangeably. 
     It is intended that reference to a range of numbers disclosed herein (for example, 1 to 10) also incorporates reference to all rational numbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5, 7, 8, 9 and 10) and also any range of rational numbers within that range (for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, all sub-ranges of all ranges expressly disclosed herein are hereby expressly disclosed. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressly stated in this application in a similar manner 
     Gaussian geometry as used in this specification means a geometry (i.e. shape) of a three dimensional shape through which the flux of a vector field is calculated, wherein the vector field is an electric field but could be a magnetic field or gravitational field. Preferably the geometry (i.e. shape) is a closed shape. Gaussian symmetry as used in this specification refers to a principle in which the geometry (i.e. shape) of an element or a surface of the element is such that an electric field is constant along the geometry. 
     This invention may also be said broadly to consist in the parts, elements and features referred to or indicated in the specification of the application, individually or collectively, and any or all combinations of any two or more said parts, elements or features, and where specific integers are mentioned herein which have known equivalents in the art to which this invention relates, such known equivalents are deemed to be incorporated herein as if individually set forth. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will now be described by way of example only and with reference to the accompanying drawings in which: 
         FIG. 1  shows an embodiment of a wireless power transfer system and components thereof. 
         FIG. 2  shows a schematic view of the operation of the wireless power transfer system and components thereof shown in  FIG. 1 . 
         FIGS. 3 to 7  show a step by step operation of the wireless power transfer system and components thereof shown in  FIG. 1 . 
         FIG. 8  shows an alternative configuration of the first and second elements of the receiver, of the wireless power transfer system. 
         FIG. 9  shows an exemplary configuration of the power supply. 
         FIG. 10  shows an exemplary implementation of the wireless power transfer system for charging a mobile device. 
         FIG. 11  shows an exemplary implementation of the wireless power transfer system for charging a wearable device. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The general terms the wireless power transfer system, components thereof and wireless power transfer method described herein, relate to an electric field based wireless power transfer system, components thereof and method. 
     In general terms the present disclosure relates to a wireless power transfer system or components thereof (more generally defined as “a wireless power transfer apparatus”) and wireless transfer power method for wirelessly transferring power from a transmitter to a load via a receiver. The wireless power transfer apparatus/method utilises an electric field to transfer power from the transmitter to the receiver. 
     In an embodiment the wireless power transfer system comprises a transmitter and a receiver. The transmitter configured to create a varying electric field. The receiver is disposed in the varying electric field. The receiver includes a first element and a second element. The first element and second element have different geometries compared to each other. The varying electric field has differing effects on the first element and the second element due their differing geometries. The varying electric field effect on each element induces differing charge densities on the first element and second element, and causes a current to flow between the first element and second element and through a load electrically connected between the first and second elements. The differing effects of the varying electric field causes charge migration between the first element and second element thereby resulting in a current flow through the load and between the first element and the second element. Energy is transferred through the varying electric field and the load harvests work done by an alternating power source that is configured to create a varying electric field from the transmitter. 
     An exemplary embodiment of a wireless power transfer apparatus and method of wireless power transfer will be described with respect to  FIGS. 1 and 2 .  FIG. 1  shows an exemplary embodiment of a wireless power transfer system  100  and components thereof.  FIG. 2  shows a schematic view of the operation of the wireless power transfer system and its components of  FIG. 1 . The wireless power transfer system  100  comprises a transmitter  110  arranged to generate an electric field  200 . The wireless power transfer system  100  further comprises a receiver  120  located within the electric field  200 . The electric field  200  may be a varying electric field. 
     Referring to  FIGS. 1 and 2 , the receiver  120  comprises a first element  122  and a second element  124 . The first element  122  and second element  124  are conductive elements and formed from any suitable conductive material, such as for example a metal. The receiver  120  is adapted for connection to a load  126 . In use, the load  126  is electrically coupled between the first element  122  and the second  124 . The receiver  120  additionally comprises a conductor  128  that extends between and electrically couples the first element  122  and second element  124 . As shown in  FIG. 1 , the load  126  is disposed between the first element  120  and the second element  124  and the load  126  is electrically coupled to the conductor  128 . In some alternative embodiments the receiver  120  may comprise the load  126  and any components that make up the load. 
     The load  126  as shown in  FIGS. 1 and 2 , is a light bulb. Alternatively the load  126  may be any other suitable component that can consume or use electrical power. In a further alternative form the load  126  may comprise a load element and an electrical circuit electrically coupled to the load element. The electric circuit, of the load  126 , may be configured for electrically transferring power to the load element wherein the load element is configured to consume power. The load and circuit could be a battery and charging circuit, for example as part of a mobile phone or wearable device such as chargeable earphones or a watch. Alternatively the load  126  may be a transformer or motor or any other suitable component that consumes electrical power. 
     The transmitter  110  comprises a conductive transmission element  112 . As shown in  FIG. 1  the transmitter  110  is connectable an alternating power source  114 . The alternating power source  114  can be an AC power source such as wall power supply or any other suitable AC power source. The alternating power source  114  is electrically connectable to the transmission element  112  through a supply conductor  116 . The alternating power source is configured to provide an alternating current to the transmission element  112  via a supply conductor  116 . The transmission element  110  is configured to generate a varying electric field due to the received alternating current. In an embodiment the transmitter  110  comprises the alternating power source  114 . 
     The transmission element  112  is a planar element. The transmission element  110  includes at least one flat or planar surface. As shown in  FIG. 1  the transmission element  110  is a plate comprising a rectangular cross section. Alternatively the transmission element  110  may comprise any other suitable shape that comprises a planar surface such as for example a tetrahedron, a dodecahedron or octahedron or any other suitable three dimensional shape with flat or planar surfaces. The transmission element  112  is preferably a solid planar element. Alternatively the transmission element  112  may be a hollow planar element. 
     The transmission element  110  can be implemented for example as a portable charging pad or integrated into furniture as a top charging surface e.g. on the top surface of a desk or table, or may be integrated into a floor as a charging floor or may be integrated into a charging pod or charging module. Additionally the transmission element  110  may be covered with an insulating material such as a plastic to avoid electrical discharge to people or other conducting devices. An insulating layer or insulating material can be disposed on the transmission element when used in as a charging pad or charging mat in the exemplary implementations described above. 
     The first element  122  and second element  124 , of the receiver  120 , comprise geometries (also termed “shapes” or “topologies”) that are different to each other. The first element  122  comprises a first geometry and the second element  124  comprises a second shape or geometry or topology, wherein the first shape or geometry or topology is different to the second geometry. The first element  122  and the second element  124  comprise three dimensional geometries that are different to each other. 
     The first element  122  comprises a planar surface. The first element  122  may be of a shape that comprises a plurality of planar surfaces. In the illustrated embodiment shown in  FIG. 1  the first element  122  is a plate or rectangular prism. The first element  122 , as shown in  FIG. 1  comprises a rectangular cross section. Alternatively for example the first element  122  may be a three dimensional polygon that comprises a plurality of planar surfaces such as for example a tetrahedron or octahedron or dodecahedron or rectangular prism. The first element  122 , of the receiver  120 , is preferably solid i.e. does not comprise a hollow interior. 
     The second element  124  comprises curved or rounded surface. The second element  124  comprises a curved or rounded three dimensional shape. In the illustrated embodiment shown in  FIG. 1  the second element  124  is a spheroid or sphere in shape. The second element  124  comprises a smooth external surface. Alternatively the second element  124  comprises a curved or rounded three dimensional shape such as for example an ellipsoid, toroid or cylindrical in shape. The second element  124 , of the receiver  120 , is preferably hollow. In the illustrated embodiment shown in  FIG. 1 , the second element  124  is a hollow sphere or spheroid. Alternatively the second element  124  may be a solid element. 
     The first element  122  and the second element  124 , of the receiver  120 , have different geometries that function as having different Gaussian geometries. The first element  122  and second element  124  comprise Gaussian geometries or shapes that are different to each other. In particular the first element  122  and second element  124  comprise geometries that are governed by different Gaussian symmetries i.e. the first and second element have Gaussian symmetry differentials. 
     The first element  122  comprises a geometry (i.e. shape) that is governed by a Gaussian plate symmetry. The second element  124  comprises a geometry (i.e. shape) that is governed by a Gaussian spherical symmetry. Alternatively the second element  124  may comprises a geometry such that the second element geometry is governed by a Gaussian toroidal symmetry or a Gaussian cylinder symmetry. 
       FIG. 2  shows a schematic view of the wireless power transfer apparatus (i.e. the wireless power transfer system and components thereof)  100  in use. Referring to  FIG. 2 , the transmitter  110  and the receiver  120  are separated by a transmission distance  300 . The transmission distance  300  may be variable. In particular the transmission distance  300  can be variable by moving the receiver  120  away or toward the transmitter  110 . The transmission distance  300  is less than the point where the transmitter  110  can be considered a point charge by the receiver  120 . 
     The first element  122  and the second element  124  are separated by a conduction distance  302 . The conduction distance  302  is greater than or equal to zero. The conduction distance  302  may be variable by moving the second element  124  away from the first element  122 . 
       FIG. 3  shows an alternative configuration of the first element  122  and second element  124 . As shown in the illustrated configuration of  FIG. 3  the second element  124  and the first element  122  are the same distance from the transmission element  112 . Therefore the first element  122  and second element  124  are both at the transmission distance  300  from the transmission element  112 . 
     As shown in  FIG. 1  and  FIG. 2  the transmission element  112  has a larger area than the first element  122  of the receiver  120 . The area of a planar surface of the transmitter  112  is greater than the area of a planar surface of the first element  122 . The transmission element  112  and the first element  122  are arranged such that a planar surface of the first element  122  is parallel to the planar transmission element  112 . As shown in  FIGS. 1 and 2 , the plate  122  of the receiver is arranged relative to the plate  112  of the transmitter, such that a flat surface of each plate  122  and  112  are arranged parallel to each other. In use, the plate  122  of the receiver is positioned to be parallel to the plate of the transmitter. The surface  112  of the transmission element is larger in area to the corresponding parallel surface of the receiver plate  122 . 
     Operation and function of the wireless power transfer system  100  will now be described in more detail with respect to  FIGS. 2-6 .  FIG. 1  shows an AC power source  114  in electrical connection with the transmission element  112 . The AC power source  114  enriches and depletes charge on the transmission element  112 . The enrichment and depletion of charge on the transmission element  112  is controlled by the switching frequency of the AC power source. In one example the switching frequency may be 50 Hz however the AC power source  114  may operate at a different frequency. Initially there is an equal charge distribution on all components of the system  100 . 
     The transmitter  110  (specifically the transmission element  112 ) becomes charged when current is supplied to it.  FIG. 2  shows the wireless power transfer apparatus  100  at one instance in time. The transmission element  112  is charged by negative charges on it and the negative charges are represented by the plurality of “−” symbols illustrated on the transmission element  112 . The static negative charge on the transmission element generates a first electric field  200  (also shown as {right arrow over (E 1 )}). The first electric field  200  is a varying electric field that is generated or provided by the transmitter  110 . The electric field  200  is created and dissipates in synchrony with the charging and discharging (i.e. enriching and depleting) of charge from the transmission element  112 .  FIG. 2  shows an illustration of the first electric field  200  when it has been created due to the presence of charge on the transmission element  112 . 
     The first electric field  200  is projected outwardly from the transmission element  112 . The first electric field  200  projects generally normal or perpendicular to the transmission element  112  since the transmission element is a plate. Alternatively the electric field  200  projects perpendicular to a flat or planar surface of the transmission element  112  if the transmission element comprises a three dimensional geometry (i.e. shape) with one or more planar of flat surfaces such as a three dimensional polygon e.g. an octahedron, rectangular prism, tetrahedron or hexahedron. 
       FIG. 3  shows the power supply  114  transferring negative charge to the transmission element  112  through the supply conductor  116 . The transmission element is a rectangular plate in the illustrated configuration. The negative charges “−” migrate to an outer surface  118  of the transmission element  112 . The first electric field  200  builds due to the increased electric charge. An electric charge produces an electric field everywhere. The electric field created due to the vector sum of the electric fields of individual charges as defined by 
               E   →     =         ∑   i     ⁢       E   ι     →       =       ∑   i     ⁢       1     4   ⁢   π   ⁢     ɛ   0         ⁢       q   i       r   i   2       ⁢       r   ^     .                 
Where E is the electric field, the electric field at a distance r and q is the point charge. As shown in  FIG. 3  due to the presence of the negative charges on the outer surface of the plate, the positive charges are pushed to the inner side  119  of the plate i.e. the side proximal to the power source.
 
     The electric field  200  interacts with the first element  122  and the second element  124  of the receiver  120 . In particular the first electric field  200  causes the first element  122  to become polarized due to charge migration of negative charge away from the planar or flat surface of the first element  122  proximal to the transmission element  112 . Negative charge moves away due to like charges repelling each other. The force exerted by two like charges q1 and q2 separated by a distance in a vacuum is given by Coulombs Law: 
                   F   →       1   ⁢   2       =       k   e     ⁢         q   1     ⁢     q   2         r   2       ⁢     r   ^         ,         
where k e  is a Coulombs constant and {circumflex over (r)}={right arrow over (r)}/r is a unit vector directed from q1 to q2. The negative charges on the transmission element  112  repel the negative charges on an proximal surface  123  of the first element  122 . The proximal surface  123  is proximal to the outer surface  118  of the transmission element  112 . As can be seen in  FIG. 4 , the proximal surface  123  becomes full of positive charges “+” and a distal surface  125  of the first element becomes negatively charged due to the charge repulsion. Opposing forces between a proximal surfaces of the transmission element  112  (i.e. first plate) and the first element  122  (i.e. second plate) causes negative charges to move away from the transmission element  112 , on the first element  122 . This results the plate of the first element  122  becoming polarized. The forces exerted on the negative charges on the first element  122  is defined by the Coulombs law equation provided above.
 
     A second electric field  202  (also shown as {right arrow over (E 2 )}) builds due to the charge on the first element  122  (i.e. second plate). The second electric field  202  has a constant effect on the first element  122  of the receiver  120 , irrespective of the transmission distance  300 . The transmission distance  300  can be any distance as long as the transmission element  112  (i.e. the first plate) is not seen as a point charge by the first element  122  of the receiver  120 . A planar or flat surface of the transmission element  112  and a planar or flat surface of the first element  122  being arranged parallel to each other to optimize interaction between the first element  122  and the first electric field  200 . The effect of a constant electric field (i.e. the first electric field  200 ({right arrow over (E 1 )})) on a plate shaped first element is in accordance to Gaussian planar symmetry. This is because the geometry of the first element  122  is one that is governed by Gaussian planar symmetry. The effect of the first electric field is defined by 
               E   →     =     σ     2   ⁢     ϵ   0               
increasing to
 
               σ     ϵ   0       .         
The effect of the first electric field on the first element strengthens over time, where ϵ 0  defines. The first electric field  200  has a constant effect on the first element  122  irrespective of the transmission distance Negative charge migrates away from the first element  122  to the second element  124  via the conductor  128 . Negative charges “−” migrate from the first element  122  to the second element  124  due to the presence of a conductive pathway  128  and due to the different effects of the first electric field  200  on the first element  122  and the second element  124 . The second electric field  202  does not build to any significant strength due the negative charge migrating from the first element  122  to the second element  124 .  FIG. 5  shows the negative charges “−” migrating along the conductive pathway  128  to the second element  124 . The negative charge “−” continues to migrate to the second element until either the first element is depleted of charge or until the second element  124  is saturated with charge.  FIG. 6  shows an example of the charge building on the second element  124  and moving away from the first element  124 . As can be seen in  FIG. 6 , the charge received at the second element  124  moves to an outer surface  127  of the second element  124 .
 
     The first electric field  200  has a lesser effect on the second element  124  as compared to the effect on the first element  122 . The effect of a constant electric field i.e. the first electric field  200  on the second element is given by 
               E   →     =     1     r   2             
increasing to
 
               1     r   3       ,         
where r in this case is equal to the total distance the second element  124  is away from the transmission element (i.e. the transmission distance  300 +the conduction distance  302 ). These equations define the effect of a constant electric field on a sphere in accordance to Gaussian spherical symmetry.
 
     The difference in the electric field effect on the first element  122  and the second element  124  is due to the first element  122  and second element  124  having different geometries, and hence different Gaussian shapes (i.e. geometries) when compared to each other. The first element  122  and second element  124  have different geometries and are governed by different Gaussian symmetries. As described earlier, in the illustrated embodiment of  FIG. 2  the first element  122  is governed by a Gaussian plate symmetry and the second element  124  is governed by a Gaussian sphere symmetry. This is because the first element  122  is a rectangular plate and the second element  124  is a sphere. As can be seen by the equations above, defining the electric field effects, the effect of the electric field on the second element is less than the effect of the electric field on the first element. This is because the second element  124  comprises a geometry (i.e. topology) that is governed by Gaussian spherical symmetry and the first element  122  comprises a geometry (i.e. topology) that is governed by Gaussian plate symmetry. The different field effect from the first electric field  200  on the first and second elements  122 ,  124  of the receiver causes a charge to migrate and hence a current to flow. Current I flows through the load  126  and hence power is utilised in accordance to Ohms Law W=I 2 .R L . The difference in the field effects strengthens over time, as shown in the equations above regarding field effect, thereby causing increased charge to migrate from the first element  122  to the second element  124 . 
     The migration of charge from the first element  122  to the second element  124  reduces the strength of the second electric field  202 . Therefore the field effect of the second electric field  202 , on the second element  124  is reduced. The second electric field  202  cannot build as charges escape from the first element  122  to the second element  124  until the second element  124  is saturated or the negative charge from the first element is depleted. As the conduction distance  302  increases, the effect of the first electric field  200  on the second element  124  is reduced thus enhancing the charge migration. The different Gaussian symmetries of the first element  122  and second element  124  induces different charge densities on the first element  122  and the second element  124 . The conductive distance  302  may be greater than or less than but is less than the point where the first electric field  200  has no effect on the second element  124  of the receiver  120 . The reduction in the field effect is proportional to transmission distance  300  plus the conductive distance  302  all cubed. 
     The second element  124  functions as a charge well. In the illustrated embodiment the second element  124  is a hollow sphere. Charge is carried inside the sphere and conducted to the outside or outer surface of the sphere (i.e. the second element  124 ) until the breakdown voltage of the second element  124  is reached or until all the negative charge from the first element  122  is depleted. The charge moves to the outer surface of the hollow sphere based on the Van der Graff principle. The charge received at the second element  124  continues to be conducted to the outside surface of the sphere  124  until a breakdown voltage is reached or until the charge on the first element  122  is depleted. 
     Negative charge moving from the first element  122  to the second element  124 , hence by convention current flow from the second element  124  to the first element  122  (since current flow is considered as flow of positive charges). The charge migration and hence current flow is caused due to the geometric differences between the first element  122  and second element  124 . When the alternating power source  114  switches polarity charge is depleted from the transmission element  112 . This depletion of charge on the transmission element causes the first electric field  200  to dissipate. Dissipation of the first electric field  200  causes the charges are redistributed in the components of the receiver i.e. charges redistribute between the first element  122  and the second element  124 . This results in a current flowing between the first element  122  and the second element  124  and through the load  126 , in the direction shown in  FIGS. 5 and 6 . Therefore when the transmission element  112  is charge enriched by the alternating power source  114 , current flows I the first element  122  to the second element  124 , via the load  126 . When the transmission element  112  is charge depleted, current I flows from the second element  124  to the first element  122  as the charges in the receiver  120  attempt to redistribute. 
       FIG. 7  illustrates shows a schematic view of the operation of the system when polarity of the power supply is switched. As shown in  FIG. 7 , the charge on the transmission element  112  redistributes along the transmission element  112 . Since there is no region of increased negative charge this causes the first electric field  200  to dissipate. Since there is no electric field  200  the negative charges from the second element  124  travel to the first element  122  in order to redistribute charge across the receiver. The negative charges move from the second element  124  to the first element  122  in this cycle via the second conductor  128 . There is a net flow of negative charge from the second element  124  to the first element  122  because the second element  124  was primarily negatively charged in the first cycle with reference to  FIGS. 3 to 6 . Hence current I flows from the first element  122  to the second element  124  (since conventionally current flow is considered as the flow of positive charges). The current flow I flows through the load  126  in the direct shown and hence the load consumes power. 
     The alternating power source  114  performs work to enrich and deplete charge from the transmitter  110 . The transmitter generates a varying electric field  200  due to the enrichment and depletion of charge. The varying electric field  200  transferred via the varying electric field  200 . The load  126  is configured to harvest the work performed by the alternating power source  114 , due to the current flowing between the first element  122  and the second element  124  of the receiver  120 . The wireless power transfer system  100  can function as a charge resonant circuit since charge can resonate between the first element  122  and the second element  124 , of the receiver  120 . The resonance frequency is dependent on the frequency of the varying electric field, which is related to the frequency of the alternating power source  114 . 
       FIG. 8  shows an alternative configuration of the first and second elements  122 ,  124  of the receiver  120 . Referring to the configuration shown in  FIG. 8 , the second element  124  is positioned at the same distance as the first element  122  from the transmission element  112 . The charge migration would still function in the configuration shown in  FIG. 8  where the first element  122  and second element  124  are equidistant from the transmission element  112 . The wireless power transfer system configuration shown in  FIG. 8  would still function the same as the configuration shown in  FIGS. 1 and 2 . In this configuration the electric field generated by the transmission element  112  will have a first effect on the first element  122  and a second effect on the second element  124  similar to that described above. The first element  122  will have charge migrate toward the second element  124  because of the different effects from the first electric field on the first element  122  and second element  124 . The first element  122  and second element  124  behave differently in response to an electric field because they comprise different geometries (i.e. shapes) as compared to each other. The first element  122  and second element  124  are governed by different Gaussian symmetries due to their geometric (i.e. shape) differences. Charge will migrate from the first element  122  to the second element  124  due to the electric field  200  having differing effects on the first element  122  and the second element  124 . 
       FIG. 9  shows an exemplary configuration of a power supply  114  that can be used. The power supply  114  may comprise a plurality of switches that control the delivery of charge to the transmission element  112 . A feature of the wireless power transfer system  100  as described herein is that there is no return line to the power supply. Existing power transfer systems such as inductive or capacitive power transfer systems require a conductive line to return and connect to the power supply. The wireless power transfer system described herein functions effectively as an open circuit because there is no return line. As shown in  FIG. 9  the power supply  114  comprises a pair of switches  302 ,  304  and the transmission element  112  is connected between the switches. The transmission element  112  is connected downstream of the first switch  302  and upstream of the second switch  304 . The switches connect between positive and negative rails  306 ,  308  of the power supply. The switches are operated to switch the polarity of the power signal delivered to the transmission element  112 . Conventional current flows from the positive rail  306  to the negative rail  308 . The first switch  302  is closed to introduce charge onto the transmission element  112 . The second switch  304  is maintained open to allow charge to build on the transmission element  112 . As the charge builds on the transmission element an electric field  200  will form (as described earlier) and have a differing effect on the first element  122  and second element  124  of the receiver  120 . The differential field effect will cause a charge migration and hence a current flow between the first element  122  and the second element  124 . 
     In order to switch polarity the second switch  304  is closed and the first switch  302  is opened such that charge can flow away from the plate toward the negative rail. The switch in polarity will cause charge to dissipate from the transmission element  112 . The switches  302  and  304  can be constantly opened and closed in the order described to charge the transmission element  112  and build the electric field  200  and discharge the transmission element  112  in order to achieve charge migration (and hence a current flow) between the first element  122  and the second element  124  of the receiver  120 . The switching rate of the switches  302 ,  304  can be predefined and is fast enough to cause current to flow between the first element  122  and second element  124  of the receiver. The power supply configuration  114  shown in  FIG. 9  may include additional smoothing circuitry or any additional circuitry that forms part of a power supply. The power supply  114  may further comprise an electronic controller (not shown) that electrically communicates with the switches  302 ,  304  to actuate the switches. The controller includes logic or computer readable instructions stored in a memory unit that cause the controller to actuate the switches based on a predetermined switching pattern. The switching pattern may define a frequency of the power source i.e. the frequency at which the transmission element is charged and discharged. The power supply configuration  114  as shown in  FIG. 9  allows supply of power to the transmission element using an open circuit since there is no return path from the receiver. 
       FIG. 10  illustrates a further embodiment of the wireless power transfer system  300 . The embodiment of the wireless power transfer system  300  functions in the same manner as the embodiment  100  shown in  FIGS. 1 and 2 . Like numbers are used to denote like features. Referring to  FIG. 10 , the wireless power transfer system  300  comprises a transmitter  310  and a receiver  320 . The transmitter  310  comprises a transmission element  312 . The transmission element  312  is a substantially planar element. In the illustrated embodiment the transmission element  312  is a rectangular plate. The plate may be rigid or may be flexible. The transmission element  312  preferably comprises a conductive element or is conductive. In one example the transmission element  312  may be a rectangular charging mat that may be disposed on or within a table, floor or may be incorporated into a portable charging pod. The transmission element  312  is substantially similar to the transmission element  112  as described. 
     In the embodiment shown in  FIG. 10 , the receiver  320  of the wireless power transfer system  300  comprises a first element  322  and a second element  324 . The first element  322  comprises a first three dimensional geometry or topology (i.e. shape) and the second element  324  comprises a second three dimensional geometry or topology, wherein the first and second geometries are different to each other. The first element  322  comprises a geometry (i.e. shape) of a three dimensional polygon that includes a plurality of flat faces. In the illustrated embodiment, of  FIG. 10 , the first element  322  is a square based pyramid in shape and has a plurality of flat faces. At least one flat face of the first element  322  is arranged substantially parallel to the transmission element  312 . The parallel arrangement maximises the field effect on the first element  322  from the electric field emanating from the transmission element in use. 
     The second element  324  comprises a three dimensional geometry including one or more curved surfaces. Preferably a majority of the second element&#39;s  324  geometry (i.e. shape) is delimited by a continuous curved surface. In the illustrated embodiment of  FIG. 10 , the second element  324  comprises a sphere. The sphere is a closed hemisphere comprising a curved surface. Alternatively the second element may be a hemisphere or a cylinder or any other closed three dimensional shape that comprises a continuous curved surface. The wireless power transfer system  300  as illustrated in  FIG. 9  functions in the same manner as the wireless power transfer system  100  as described with reference to  FIGS. 2 to 7 . The transmission element  312  is electrically coupled to the power supply  314 . The transmission element  312  is charged with a changing polarity which creates and dissipates an electric field. The changing electric field induces charge migration between the first and second elements  322 ,  324 , thereby causing a current to flow through the load  326  interconnected between the first and second elements. The charge migration is caused due to the differing effect of the electric field on the first and second elements  322 ,  324 . 
       FIG. 10  further shows an exemplary implementation of the wireless power transfer system  300 . The wireless power transfer system  300  is utilised to charge the battery of a phone. The transmission element  312  can be charging mat or a charging pad positioned on a table or located in a charging surface of a charging pod. The receiver  320  is located within the mobile device  340 , which in  FIG. 10  is a mobile phone. However the mobile device can be any other mobile or wearable device such as earphones, a tablet, a smartphone, a fitness tracker and the like. The transmission element  312  induces a differential charge on the first and second elements of the receiver  320  positioned within the mobile device  340 . The load  326  is preferably a rechargeable battery. Alternatively load element  326  may be any suitable component or circuit that consumes electrical power such as for example lamp or transformer or motor or any other suitable component or circuit. The receiver  320  is located within a housing of the mobile phone and may be formed on a circuit board such as printed circuit board with the other electronics of the mobile device  340 . 
       FIG. 11  shows another exemplary use of the wireless power transmission system  100 . Referring to  FIG. 11  the wireless power transmission system  100  is used to charge a rechargeable battery  426  within a wearable device  440 . The wearable device  440  may be a watch or a fitness tracker or a physiological monitor or any other wearable device. The wearable device  440  comprises a body  442 , and the receiver  420  is retained within the body  442 . The receiver  420  includes a first element  422  and a second element  424  and a load element  426 . The load element  426  is a rechargeable battery or a battery recharging circuit. The load  426  is connected to a ground pin or wire. The transmitter  410  comprises a transmission element  412  that is connected to a power supply  414 . The transmission element  412  is preferably plate shaped and may be a charging mat or charging pad disposed on a table or other structure. The power supply  414  may have a similar configuration to the power supply shown in  FIG. 9 . The first element  422  and the second element  424  may be arranged in a similar configuration to that shown in  FIG. 8 , just within the body  442  of the wearable device  440 . The wearable device  440  includes a strap  444  to attach the device onto a user. The body  442  defines a hollow housing that retains the receiver  420 , its components and other electronics. The receiver  420  may be formed on a circuit board such as a printed circuit board. In other exemplary forms the load elements  426  may be a lamp or a motor or a transformer or any other suitable electrical component or electrical circuit that consumes electrical power. 
     The transmission element and, the first element and second element of the receiver, are made of conductive materials such as metals or conductive plastics. The transmission element and, the first element and second element of the receiver, may also include additional insulating materials such as a layer of plastics material or silicone material to prevent shocks to users due to touching the wireless power transfer system. 
     In another exemplary embodiment the present invention relates to a wireless power transfer system comprising; a transmitter configured to create a varying electric field and a receiver within the varying electric field. The receiver in the varying electric field being separated from the transmitter and the receiver comprising a first element and a second element. The first element having a first geometry or topology and the second element having a second different geometry or topology to the first element. The electrical characteristics/behaviour of each element being different to each other when in the varying electric field, such that a current flows between the first element and second element when connected to a load due to interaction between the varying electrical field and the first element and the second element. The transmitter comprises a plate, the first element is a plate and the second element is a sphere (or other spheroid). Preferably the first element is governed by Gaussian planar symmetry and the second element is governed by Gaussian spherical symmetry. However alternatively other geometries for the first element and second element are contemplated. The first element and second element comprise geometries that are different to each other. The electric characteristic of each element being the polarization of each element in the presence of the varying electric field. The varying electric field polarizing the first element of the receiver to a first level, the varying electric field polarizing the second element of the receiver to a second level, wherein the difference in polarization causes a current to flow between the first element and second element and through a load electrically connected between the first and second element. 
     Alternatively the electric characteristic may be the electrical field effect from the varying electric field, wherein the first and second elements experience a different electrical field effect thereby causing a current to flow through a load connected between the first and second element. Each of the first and second elements experience a different electrical field effect due to the different geometry/topology of the first and second elements. 
     The wireless power transfer system as described herein is advantageous because it does not include a return path. The wireless power transfer system is advantageous because it creates a current flow through a load in an open circuit and hence does not require a closed circuit. This is advantageous because the wireless power transfer system  100  can be simpler to construct and use as there is no return path needed back to the power source. The power supply configuration comprises switches, as shown in  FIG. 9 , is advantageous because it allows charging and discharging of the transmitter element using an open circuit. The power supply configuration does not require any return path and uses the switches to control polarity. 
     The wireless power transfer system as described herein utilizes a varying or switching electric field acting on two differently shaped elements of a receiver to achieve a current flow between the two elements. In particular the two elements comprise two different Gaussian symmetries that induces differing charge densities on the two elements and thereby causes a current to flow. The wireless power transfer system is advantageous as power is transferred wirelessly. Further the wireless power transfer system  100  is advantageous because it utilises a varying electric field to create work in the conductor (i.e. conductive wire) of the receiver, and the power is harvested by the load of the receiver. 
     The wireless power transfer system allows for increased transmission distances as compared to other power transfer methodologies. The use of an electric field to transfer power between a transmitter and receiver allows for a greater transmission distance because an electric field can act over greater distances than inductive coupling systems. 
     The nature of power transfer due to or via an electric field, also allows for the potential for miniaturization of the system as long as the transmission element is sufficiently larger in size than the first element of the receiver. Size as referred to above can mean surface area of the transmission element and first element. Alternatively size may mean the area of a planar surface of the transmission element is larger than the area of a corresponding parallel planar surface of the first element of the receiver. The wireless power transfer system as described herein can be more readily miniaturized than an inductive power transfer system since there are no coils in the system. 
     Further the wireless power transfer system as described herein produces less heat, and is immune to foreign objects located between the transmitter and receiver and can also act through electrically isolated metal. 
     The wireless power transfer system as described herein can potentially be used in a variety of uses. Some exemplary products or uses could be for wireless charging of wearable devices or wireless power transfer in MEMs devices. Other applications are also contemplated herein.

Metadata:
Filing Date: 20180802
Publication Date: 20220118
Grant Date: 20220118
Priority Date: 20170802
Inventors: WALTON, ROBERT
Assignee: APPLE INC
CPC Classifications: [{"code": "H02J50/05", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/05", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J50/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/025", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J50/05", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 79293813