Abstract:
Power delivery systems and methods for delivering power from a vehicle to a vehicle door. The system includes a supporting device having a first portion fixedly mounted to a main frame and a second portion attached to a door. The second portion being movable about a hinge axis portion that connects the first portion to the second portion. An energy transmitting source is connected to a power frequency generator. The power frequency generator is connected to a power source and configured to couple an oscillating signal to the energy transmitting source. The energy transmitting source is mounted on the hinge axis portion of the supporting device. An energy receiving device is magnetically coupled to the energy transmitting source to receive a power signal from the energy transmitting source. The energy receiving device is mounted on the second portion of the supporting device at a fixed distance from the energy transmitting source. The energy receiving device receives the power signal from the energy transmitting source to deliver the power signal to powered components associated with the door. The power delivery is uninterrupted during opening and closing of the door.

Description:
[0001]    The invention relates to power-assisted door systems, and more particularly, to contactless power delivery in power-assisted door systems. 
       BACKGROUND 
       [0002]    Power-assisted doors on vehicles are used to allow a user to open or close doors that may be difficult to control due to their size and weight. For example, military vehicles such as High Mobility Multipurpose Wheeled Vehicles (HMMWVs, or “Hummvees”) are often provided with added armor that adds sufficient weight to the door to make it difficult to open and close without power-assistance. Power-assisted door systems use electric motors and mechanical assemblies to generate a controlled force to assist the user with the heavy doors. 
         [0003]    The use of power-assisted door systems has complicated the delivery of power from the vehicle to the door of the vehicle. Power cables are typically used to deliver power from the vehicle to the door. Power cables may get caught between the door and vehicle frame. Repeated opening and closing of the vehicle door may result in significant wear and tear on the power cables as the cables are bent, stretched, twisted, pinched and otherwise battered during the movement of the door. 
         [0004]    Contactless energy delivery systems have been developed to deliver power to a powered vehicle door. However, conventional contactless systems only deliver energy when the vehicle door is adjacent to the frame of the vehicle, which occurs when the door is in the closed position. Power delivery systems have not been able to provide power-assisted doors with continuous power delivery during the opening and closing of the doors. 
         [0005]    There is a need for a contactless power delivery system that provides continuous power delivery during opening and closing of a door. 
       SUMMARY 
       [0006]    In view of the above, a power delivery system is provided for delivering power from a vehicle to a vehicle door. The system includes a supporting device having a first portion fixedly mounted to a main frame and a second portion attached to a door. The second portion being movable about a hinge axis portion that connects the first portion to the second portion. An energy transmitting source connected to a power frequency generator. The power frequency generator is connected to a power source and configured to couple an oscillating signal to the energy transmitting source. The energy transmitting source is mounted on the hinge axis portion of the supporting device. An energy receiving device is magnetically coupled to the energy transmitting source to receive a power signal from the energy transmitting source. The energy receiving device is mounted on the second portion of the supporting device at a fixed distance from the energy transmitting source. The energy receiving device receives the power signal from the energy transmitting source to deliver the power signal to powered components of the door. The power delivery is uninterrupted during opening and closing of the door. 
         [0007]    In one example implementation, the energy receiving device includes an extended power conducting rod connected to a receiving coil. A mobile coil is configured to move along the extended power conducting rod to maintain a magnetic coupling with the extended power conducting rod as the door is opened or closed. 
         [0008]    In another example implementation, the energy receiving device includes a U-shaped energy receiving device made of magnetic material and mounted to maintain a magnetic coupling with the energy transmitting device. A mobile coil is configured to move along the U-shaped energy receiving device to maintain a magnetic coupling with the U-shaped energy receiving device as the door is opened or closed. 
         [0009]    Other systems, methods and features of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The examples of the invention described below can be better understood with reference to the following figures. The components in the figures are not necessarily to scale or in their actual position in any given implementation, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views. 
           [0011]      FIG. 1A  is a schematic diagram of an example of a contactless power delivery system in a power-assisted door. 
           [0012]      FIG. 1B  shows an example of an implementation of the system shown in  FIG. 1A . 
           [0013]      FIG. 2A  is a schematic diagram of another example of a contactless power delivery system in a power-assisted door. 
           [0014]      FIG. 2B  shows an example of an implementation of the system shown in  FIG.2A . 
           [0015]      FIG. 3A  is a schematic diagram of another example of a contactless power delivery system in a power-assisted door. 
           [0016]      FIG. 3B  shows an example of an implementation of the system shown in  FIG. 3A . 
           [0017]      FIGS. 4A ,  4 B and  4 C illustrate operation of the contactless power delivery system during the opening of a power-assisted door. 
           [0018]      FIG. 5  is a schematic diagram of an example of a frequency generator. 
           [0019]      FIG. 6  is a schematic diagram of an example of a conditioning unit. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    In the following description of example embodiments, reference is made to the accompanying drawings that form a part of the description, and which show, by way of illustration, specific example embodiments in which the invention may be practiced. Other embodiments may be utilized and structural changes may be made without departing from the scope of the invention. 
         [0021]      FIG. 1A  is a circuit diagram of an example of a contactless power delivery system in a vehicle  100  having a power-assisted door  102 . The vehicle  100  includes a vehicle power source  112 , a power frequency generator  104 , and an energy transmitting source  106 . The vehicle door  102  includes an energy receiving device  108  and a conditioning unit  110 . The contactless power delivery system provides power to the vehicle door  102  without the need to extend any wires from the vehicle  100  into the door  102 . The vehicle door  102  may be mounted to the vehicle  100  on a hinge (not shown) that allows the vehicle door  102  to swing open and closed about the hinge. The vehicle door  102  may be power-assisted using an electric motor or hydraulic assembly to provide a force on the door in order to open or close the vehicle door  102 . The contactless power delivery system in  FIG. 1A  is configured to provide uninterrupted power from the vehicle power source  112  to components that require electric power in the vehicle door  102  during the opening or closing of the vehicle door  102 . 
         [0022]    The vehicle power source  112  may be a vehicle battery or any other suitable power source within the vehicle to provide electric power to the components in the vehicle that require power. The vehicle power source  112  is connected to provide power to the power frequency generator  104 . As an example, the vehicle power source  112  may provide a DC bias to an oscillator circuit, which generates an oscillating signal with a voltage swing determined by the voltage level of the vehicle power source  112 . The power frequency generator  104  may generate an AC signal having a peak positive and negative voltage level based on the voltage level of the vehicle power source  112 . The oscillating signal may be coupled to the energy transmitting source  106 , which generates an oscillating magnetic field. The energy transmitting source  106  in the example shown in  FIG. 1A  is a transmitting coil, and the energy receiving device  108  is a receiving coil. 
         [0023]    The energy transmitting source  106  and the energy receiving device  108  may be inductively coupled to permit the transfer of electrical energy between the energy transmitting source  106  in the vehicle  100  to the energy receiving device  108  in the vehicle door  102 . The energy receiving device  108  receives the oscillating signal via the inductive coupling and couples the oscillating signal to the conditioning unit  110 . The conditioning unit  110  may include a rectifier or other power conversion components to provide a DC power source to components in the vehicle door  102 . The conditioning unit  110  may also provide an AC power signal using the energy obtained from the oscillating signal received from the energy receiving device  108 . The oscillating signal may also be delivered as a power source to electrical components in the vehicle door  102  without using a conditioning unit  110 . 
         [0024]    In example implementations, the contactless power delivery system in  FIG. 1A  provides uninterrupted power even as the door is opening or closing. Vehicle doors on vehicles that use power-assisted door systems to open and close the doors are subject to rotational movement about a hinge. Such vehicle doors have a movement profile that is primarily rotational movement. Some vehicles are equipped with armor or other components on the doors that may provide a substantial obstacle for power-assist components near the hinge axis portion of the door. The power assist components are typically mounted in a position that is offset from the door hinge. The movement profile for such vehicle doors includes a linear movement in addition to rotational movements. The linear movement may result from the separation of the power assist components from the door hinge, or in some cases, from actual linear movement of the door relative to the door hinge. For example, the power assistance mechanism for a vehicle door of an armored vehicle may include a door-opening component, such as for example, a hydraulic cylinder that moves a piston in and out as the vehicle door rotates open and closed. In order to accommodate the movement of the door-opening component, the vehicle door may be designed to also move linearly along the vehicle frame as the door is opened and closed. Example implementations of the contactless power delivery system may be configured to operate on vehicle doors exhibiting rotational and linear movement as well as doors exhibiting only rotational movement. 
         [0025]      FIG. 1B  is a schematic diagram illustrating implementation of a first example of a contactless power delivery system 120  in a power-assisted door. The contactless power delivery system  120  in  FIG. 1B  is configured to operate on a vehicle door  124  having rotational movement about a hinge  128 , which connects the door  124  to a vehicle frame  122 . The hinge  128  includes a fixed hinge portion  132  attached to the vehicle frame  122  and a rotating hinge portion  130  attached to the vehicle door  124 . The rotating hinge portion  130  rotates about a hinge axis portion, which connects the rotating portion  130  to the fixed portion  132 . 
         [0026]    The contactless power delivery system  120  in  FIG. 1B  includes a transmitting coil  134  mounted on the hinge axis portion that holds the rotating hinge portion  130  to the fixed hinge portion  132 . The transmitting coil  134  may be mounted on a transmitting coil base  136  that may be mounted on the hinge axis portion of the hinge  128 . The transmitting coil  134  may also be integral with the hinge axis portion. For example, the transmitting coil  134  may be formed with a rigid extension to fit into a hinge as a substitute hinge axis portion. The transmitting coil  134  operates as the energy transmitting source  106  shown in  FIG. 1A . A receiving coil base  138  may be affixed to the rotating hinge portion  130  to support a receiving coil  140 . The receiving coil  140  may also be mounted directly on the rotating hinge portion  130  without a receiving coil base  138 , or using other suitable mounting structures. The receiving coil  140  operates as the energy receiving device  108  in  FIG. 1A . 
         [0027]    The transmitting coil  134  is connected to a power frequency generator (not shown in  FIG. 1B ) via the source power connections  144  to receive an oscillating signal as described above with reference to  FIG. 1A . The receiving coil  140  is connected to a conditioning unit or a load (not shown in  FIG. 1B ) via load power connections  142  to provide power to components on the vehicle door  124 . 
         [0028]    The receiving coil  140  and transmitting coil  134  are positioned on their corresponding hinge portions so that the receiving coil  140  remains a fixed distance from the transmitting coil  134  as the receiving coil  140  moves with the motion of the vehicle door  124  about the transmitting coil  134 . By retaining a fixed distance between the transmitting coil  134  and the receiving coil  140 , the power transfer via the inductive coupling between the transmitting coil  134  and the receiving coil  140  is not interrupted by the motion of the door  124 . 
         [0029]      FIG. 1B  illustrates an example of a contactless delivery system  120  for a vehicle  122  having a vehicle door  124  with a rotational movement profile. Examples described below with reference to  FIGS. 2A ,  2 B,  3 A, and  3 B may implement contactless delivery systems in vehicles having doors with rotational and linear movement profiles. 
         [0030]      FIG. 2A  is a schematic diagram of another example of a contactless power delivery system  200  used in a vehicle  202  having a power-assisted door  204  in which the power-assisted door  204  has a rotational and linear movement profile. The contact delivery system  200  includes a vehicle power source  206  connected to a power frequency generator  208 . The power frequency generator  208  is connected to an energy transmitting source  210 . The power frequency generator  206  and energy transmitting source  210  are mounted in the vehicle  202 , and the energy transmitting coil  210  is positioned near the structure attaching the door  204  to the vehicle  202 . 
         [0031]    The contactless power delivery system  200  also includes a receiving coil  212 , an extended power conductor  214 , a mobile coil  216 , a conditioning unit  220 , and door power terminals  222 . The vehicle power source  206  provides a power source in the form of a DC voltage level, for example, to the power frequency generator  208 . The power frequency generator  208  generates an oscillating signal from the power source and outputs the oscillating power signal to the energy transmitting source  210 . The energy transmitting source  210  generates an oscillating magnetic field that is inductively coupled to the receiving coil  212 . The receiving coil  212  generates a received oscillating power signal as current flowing in the extended power conductor  214 . The current of the oscillating power signal flowing in the extended power conductor  214  generates an oscillating magnetic field that is inductively coupled to the mobile coil  216 , which generates a corresponding oscillating power signal. The oscillating signal generated by the mobile coil  216  is coupled to the conditioning unit  220 . The conditioning unit  220  uses the oscillating power signal to generate a door power source at the door power terminals  222 . 
         [0032]    The contactless power delivery system  200  in  FIG. 2A  allows for delivery of the vehicle power to electrical components in the vehicle door  204  without interruption even as the vehicle door  204  is opened and/or closed. In addition, the mobile coil  216  reduces the need for excess wiring to compensate for the door movement thereby reducing the potential for tangling and cutting of any power delivery conductors. 
         [0033]      FIG. 2B  shows an example of an implementation of the system shown in  FIG. 2A . The contactless power delivery system  240  in  FIG. 2B  is configured to operate on a vehicle frame  242  having a vehicle door  244  with both a rotational and linear movement profile. The vehicle door  244  may be attached to the vehicle frame  242  at a hinge  250 . The components of the power-assist system provide linear push and pull forces to a clevis  246  fixed to the vehicle frame  242  at a clevis mounting portion  248 . 
         [0034]    The clevis  246  in  FIG. 2B  includes a fixed clevis portion  246   a  and a rotating clevis portion  246   b.  The fixed clevis portion  246   a  includes a hinge axis portion (not shown) positioned in the fixed clevis portion  246   a  to hold the rotating clevis portion  246   b  and to permit the rotating clevis portion  246   b  to rotate about the hinge axis portion. The contactless power delivery system  240  includes a transmitting coil  260  affixed to the fixed clevis portion  246   a  to align with the hinge axis portion, and a receiving coil  270  mounted on the rotating clevis portion  246   b.  The transmitting coil  260  may be affixed to the hinge axis portion of the clevis  246  by any suitable fixing scheme by mounting directly on the hinge axis portion, or by a mediating device such as a mounting base. The transmitting coil  260  may also be integral with the hinge axis portion. For example, the transmitting coil  260  may be formed with a rigid extension to fit into the clevis  246  as a substitute hinge axis portion. 
         [0035]    The transmitting coil  260  operates as the energy transmitting source  106  in  FIG. 1A . The receiving coil  270  operates as the energy receiving device  108  in  FIG. 1A , and receives signals from the transmitting coil  260  via magnetic coupling. The receiving coil  270  is positioned on the rotating clevis portion  246   b  a distance R along a radius extending from the hinge axis portion of the fixed clevis portion  246   a.  In an example implementation, the receiving coil  270  may include a magnetic core  270   a  (in  FIG. 2B ) having first and second ends  270   b,c  extending from a coil wire  270   d.  Each of the first and second ends  270   b,c  may 
         [0036]    Patent include an arcuate-defined surface that faces the transmitting coil  260  along a circumference at the fixed radial distance R. 
         [0037]    The power assist components on the door  244  of the vehicle  242  in  FIG. 2B  include an extending rod  278  operating cooperatively with a door-opening device  276  and the rotating clevis portion  246   b  to push and pull the door  244  to an open or closed position. The extending rod  278  is fixed at the rotating clevis portion  246   b  extending radially from the hinge axis portion of the fixed clevis portion  246   a.  The door-opening device  276 , which may include a hydraulic cylinder, is fixed at a point on the door  244 . The door-opening device  276  moves along the extending rod  278  using hydraulic or electrical energy to create a linear force along the extending rod  278  that pushes against the rotating clevis portion  246   b  when opening the door  244 . As the door is opening, the distance between the door-opening device  276  and the rotating clevis portion  246   b  increases along the extending rod  278 . As the door is closing, the distance between the door-opening device  276  and the rotating clevis portion  246   b  decreases along the extending rod  278 . 
         [0038]    The contactless power delivery system in  FIG. 2B  includes an extended power conductor  272  attached to the rotating clevis portion  246   b  at an extended conductor bracket  254 . The extended power conductor  272  extends substantially parallel to the extending rod  278  and substantially parallel to the door  244  towards the door-opening device  276 . The extended power conductor  272  may be any metal, or electrically conductive material, that is sufficiently long and sufficiently rigid to allow a coil formed around the conductor  272  to repeatedly move along the length of extended power conductor  272 . The extended power conductor  272  in  FIG. 2B  is U-shaped with an open end positioned at the extended conductor bracket  254  and a closed end positioned next to the door-opening device  276 ; however, any suitable shape may be used. The length of the extended power conductor  272  should be at least the maximum length of the extending rod  278 , such as when the door  244  is at its most open position. The two ends of the U-shaped extended power conductor  272  that form the open side of the ‘U’ shape attached to the rotating clevis portion  246   b  using the extended conductor bracket  254  to place the two ends of the extended power conductor  272  near the receiving coil  270 . The extended power conductor  272  is connected to the receiving coil  270  to form a closed loop with the receiving coil  270 . 
         [0039]    The contactless power delivery system in  FIG. 2B  also includes a mobile coil  280  configured to move linearly substantially in parallel with the extending rod  278 . The mobile coil  280  shown in  FIG. 2B  forms a collar around the extended power conductor  272  allowing the mobile coil  280  to move along the length of the extended power conductor  272  as the door  244  moves. The mobile coil  280  in  FIG. 2B  is attached to the door-opening device  276  and moves with the door-opening device  276  along the extended power conductor  272  as the door  244  opens and closes. The mobile coil  280  is inductively coupled to the extended power conductor  272  and maintains the inductive coupling as the mobile coil  280  moves along the extended power conductor  272 . When the transmitting coil  260  generates an oscillating signal, the receiving coil  270  receives the oscillating signal through inductive coupling with the transmitting coil  260 . The oscillating signal is coupled to the ends of the extended power conductor  272  and the oscillating current in the extended power conductor  272  forms a magnetic field that couples the oscillating signal to the mobile coil  280  for delivery to a load, or a conditioning unit via a door power terminal  282 . 
         [0040]      FIG. 3A  is a schematic diagram of another example of a contactless power delivery system  300  used in a vehicle  302  having a power-assisted door  304  in which the power-assisted door  304  has a rotational and linear movement profile. The contact delivery system  300  includes a vehicle power source  306  connected to a power frequency generator  308 . The power frequency generator  308  is connected to an energy transmitting source  310 . The power frequency generator  306  and energy transmitting source  310  are mounted in the vehicle  302 , and the energy transmitting coil  310  is positioned near the structure attaching the door  304  to the vehicle  302 . 
         [0041]    The contactless power delivery system  300  also includes an energy receiving device  312 , a mobile coil  314 , a conditioning unit  320 , and door power terminals  322 . The vehicle power source  306  provides a power source in the form of a DC voltage level, for example, to the power frequency generator  308 . The power frequency generator  308  generates an oscillating signal from the power source and outputs the oscillating power signal to the energy transmitting source  310 . The energy transmitting source  310  generates an oscillating magnetic field that is inductively coupled to the energy receiving device  312 . The energy receiving device  312  generates a received oscillating power signal as an oscillating magnetic field that is inductively coupled to the mobile coil  314 , which generates a corresponding oscillating power signal. The oscillating signal generated by the mobile coil  314  is coupled to the conditioning unit  320 . The conditioning unit  320  uses the oscillating power signal to generate a door power source at the door power terminals  322 . 
         [0042]    The contactless power delivery system  300  in  FIG. 3A  allows for delivery of the vehicle power to electrical components in the vehicle door  304  without interruption even as the vehicle door  304  is opened and/or closed. In addition, the mobile coil  316  reduces the need for excess wiring to compensate for the door movement thereby reducing the potential for tangling and cutting of any power delivery conductors. 
         [0043]      FIG. 3B  is a schematic diagram illustrating implementation of another example of a contactless power delivery system in a power-assisted door. The contactless power delivery system  350  in  FIG. 3B  is configured to operate in a vehicle frame  352  having a vehicle door  354  with a rotational and linear movement profile. The vehicle door  354  may be attached to the vehicle frame  352  at a hinge  360 . The components of the power-assist system may be configured to provide linear push and pull forces to a clevis  356  fixed to the vehicle frame  352  at a clevis mounting portion  358 . 
         [0044]    The clevis  356  in  FIG. 3B  includes a fixed clevis portion  356   a  and a rotating clevis portion  356   b.  The fixed clevis portion  356   a  includes a hinge axis portion (not shown) positioned in the fixed clevis portion  356   a  to hold the rotating clevis portion  356   b  to permit the rotating clevis portion  356   b  to rotate about the hinge axis portion. The contactless power delivery system  350  includes a transmitting coil  370  affixed to the fixed clevis portion  356   a  to align with the hinge axis portion, and an energy receiving device  380  mounted on the rotating clevis portion  356   b.  The transmitting coil  370  may be affixed to the hinge axis portion of the clevis  356  by any suitable fixing scheme; such as by mounting directly on the hinge axis portion, or by using a mediating device such as a mounting base. The transmitting coil  370  may also be integral with the hinge axis portion. For example, the transmitting coil  370  may be formed with a rigid extension to fit into the clevis  356  as a substitute hinge axis portion. 
         [0045]    The transmitting coil  370  operates as the energy transmitting source  310  in  FIG. 3A . The energy receiving device  380  is mounted on the rotating clevis portion  356   b  with one end positioned a distance R from the fixed clevis portion  256   a  along a radius extending from the hinge axis portion. 
         [0046]    The energy receiving device  380  in  FIG. 3B  includes a ‘U’-shaped rod made of a magneto-soft material (for example, a ferrite, or ferrite composite) having two ends at the open side of the ‘U’ positioned to be at the fixed distance R from the transmitting coil  370 . The energy receiving device  380  may be attached to the rotating clevis portion  356   b  using a bracket  384  so as to maintain the fixed distance R from the transmitting coil  370 . The two ends of the open side of the ‘U’ at  380   a,b  may have an arcuate profile to maintain the fixed distance R at any point on the surface of the ends. 
         [0047]    The energy receiving device  380  extends substantially parallel to the door  354  towards a door-opening device  386 . An extending rod  388  extends between the door-opening device  386  and the rotating clevis portion  356   b.  The extending rod  388  is fixed at the rotating clevis portion  356   b.  The door-opening device  386 , which may include a hydraulic cylinder, moves along the extending rod  388  using hydraulic or electrical energy to create a linear force along the extending rod  388  that pushes against the rotating clevis portion  356   b  when opening the door  354 . As the door  354  is opening, the distance between the door-opening device  386  and the rotating clevis portion  356   b  increases along the extending rod  388 . As the door  354  is closing, the distance between the door-opening device  388  and the rotating clevis portion  356   b  decreases along the extending rod  388 . 
         [0048]    The contactless power delivery system in  FIG. 3B  includes a mobile coil  390  that forms a collar around the energy receiving device  380 . The mobile coil  390  in  FIG.3B  is attached to the door-opening device  386  and configured to move with the door-opening device  386  along the energy receiving device  380  as the door  354  opens and closes. The mobile coil  390  is magnetically coupled to the energy receiving device  380 . When the transmitting coil  370  generates an oscillating signal, the energy receiving device  380  receives the oscillating signal through a magnetic coupling with the transmitting coil  370  at the two ends close to the transmitting coil  370 . The oscillating signal is induced in the magnetic energy receiving device  380  creating an oscillating magnetic field that transfers energy to the mobile coil  390 . The mobile coil  390  generates the oscillating signal for delivery to a load or a conditioning unit via the door power terminals  392 . 
         [0049]      FIGS. 4A ,  4 B and  4 C illustrate operation of a contactless power delivery system  400  during the opening of a power assisted door.  FIG. 4A  shows a vehicle wall  402  at a portion of the vehicle at which a vehicle door  404  attaches via a hinge axis portion  405 . The door  404  in  FIG. 4A  is shown in a closed position. The contactless power delivery system  400  shown in  FIG. 4A  operates cooperatively with power assisted door opening components that include a first clevis point  406 , a fixed clevis portion  408 , a rotating clevis portion  410 , an extending rod  412 , a cylinder  414 , and a second clevis point  418 . The contactless power delivery system  400  includes components  420  illustrated in  FIG. 4A  as detached from the power assisted door  404  and its components. The contactless power delivery system components  420  include a transmitting coil  422 , a receiving coil  424 , an extended power conductor  426  and a mobile coil  430 . 
         [0050]    The attachment of contactless power delivery system components  420  to power assisted door opening components is illustrated by dotted lines at A, B, and C. The lines A, B, and C indicate points on the power assisted door opening components at which the corresponding components of the contactless power system  420  are attached. For example, the transmitting coil  422  is attached to the fixed clevis portion  408  as indicated by broken line A. The receiving coil  424  is affixed to the rotating clevis portion  410  as indicated by broken line B. The mobile coil  430  is attached to the cylinder  414  as indicated by broken line C. The transmitting coil  422  is mounted on the fixed clevis portion  408  on the axis of rotation of the first clevis point  408  and thus remains fixed whether the door is opening or closing. The receiving coil  424  is mounted on the rotating clevis portion  410  such that it is a fixed distance from the transmitting coil  422  as the door is opened or closed. The mobile coil  430  moves with the motion of the cylinder  414  as the cylinder  414  moves against the extending rod  412  to open or close the door  404 . As noted, the door  404  is in a closed position in  FIG. 4A . 
         [0051]      FIG. 4B  shows the door  404  partially opened conveying the state of the door  404  during the opening of the door  404 . The door  404  is illustrated as following an angular path along indicated by arcuate arrow R. As the door  404  opens, the extended rod  412  lengthens as the cylinder  414  moves the door outward. The outward motion of the door  404  and the linear motion of the cylinder  414  move the mobile coil  430  as indicated by arrow S along the extended power conductor  426 . The receiving coil  424  moves radially about the transmitting coil  422  a fixed distance from the transmitting coil  422 . The fixed distance between the transmitting coil  422  and receiving coil  424  keeps the energy transfer from the transmitting coil to the receiving coil  424  substantially constant as the door  404  moves outward along the angular path R. The energy transfer generates the corresponding current through the extended power conductor  426 . The mobile coil  430  slides along the extended power conductor  426  as the door moves outward without any loss of power transfer. 
         [0052]    In  FIG. 4C , the door  404  is shown in a substantially more open position. The length of the extending rod  412  is even greater as it extends away from the cylinder  414 . The mobile coil  430  is shown further along the extended power connector  426  to correspond with the motion of the cylinder  414  as the door opens. The mobile coil  430  moves along the extended power conductor  426  without any loss of power transfer. 
         [0053]      FIG. 5  is a schematic diagram of a frequency generator  500  that may be used to generate an oscillating power signal from a vehicle DC power supply. The frequency generator  500  includes an oscillator  502  connected to a switch driver  506 . The switch driver  506  opens and closes switches in a DC to AC converter  510 . The DC to AC power converter  510  includes a first switch S 1  connected in parallel to a first diode D 1 , a second switch SW 2  connected in parallel to a second diode D 2 , a third switch SW 3  connected in parallel with a third diode D 3 , and a fourth switch SW 4  connected in parallel to a fourth diode D 4 . The switches SW 1 , SW 2 , SW 3 , and SW 4  and diodes D 1 , D 2 , D 3 , and D 4  are connected in a well-known circuit that converts the DC voltage at DC terminals  550  to an AC voltage at AC terminals  560 . The DC-to-AC converter  510  transfers a positive DC voltage level to one of the AC terminals  560  and a negative DC voltage level to the other AC terminal  560  alternating between the AC terminals  560  in accordance with the state of the switches SW 1 , SW 2 , SW 3 , and SW 4 . 
         [0054]    The state of the switches SW 1 , SW 2 , SW 3 , and SW 4  is controlled by the oscillating signal generated by the frequency generator  500 . The frequency of the AC voltage corresponds to the frequency of the oscillating signal. The switch driver  506  receives the oscillating signal and generates a pulse to the switch driver outputs SWOUT 1 , SWOUT 2 , SWOUT 3 , and SWOUT 4  in a pattern that turns the switches SW 1 , SW 2 , SW 3 , and SW 4  on and off to generate the desired AC voltage. 
         [0055]      FIG. 6  is a schematic diagram of an example of a conditioning unit  600 . The conditioning unit  600  may be implemented in a contactless power delivery system such as systems described above with reference to  FIGS. 1A ,  1 B,  2 A,  2 B,  3 A, and  3 B to convert an AC voltage received from a vehicle power source to a corresponding DC power source used by electrical components in a door. The conditioning unit  600  receives an AC voltage from a mobile coil  602  formed around a power conductor  610 . The mobile coil  602  may be formed with a collar-shaped ferrite material with a coil wire  604  wrapped around the ferrite collar. The coil wire  604  generates an AC voltage when AC current flows in the power conductor  604 . The AC voltage is coupled to conditioning unit input terminals  606  for input to the conditioning unit  600 . The conditioning unit  600  includes a resonance capacitor RC connected between rectifier diodes D 1  and D 2 . Diode D 1  outputs a DC voltage level at a filter capacitor FC, which couples the DC voltage level to conditioning unit output terminals  612 . 
         [0056]    The conditioning unit  600  in  FIG. 6  illustrates one example of a circuit that may be used to condition electrical energy received from a vehicle power source at the mobile coil output for use as a power source for electrical components on the door. Other suitable conditioning units may be implemented according to the specific requirements of a specific implementation. In some implementations, a conditioning unit may not be needed. 
         [0057]    Examples of contactless power delivery systems for use with power-assisted door have been described with reference to  FIGS. 1A through 6 . The example implementations may be built into the vehicle and door as original equipment. Alternatively, the contactless power delivery system may be provided as a kit for installation as a retrofit in an existing vehicle and power-assisted door system. 
         [0058]    It will be understood that the foregoing description of numerous implementations has been presented for purposes of illustration and description. It is not exhaustive and does not limit the claimed inventions to the precise forms disclosed. Modifications and variations are possible in light of the above description or may be acquired from practicing the invention. The claims and their equivalents define the scope of the invention.