Vehicle to wireless power transfer coupling coil alignment sensor
A non-contacting position sensing apparatus includes at least one vehicle-mounted receiver coil that is configured to detect a net flux null when the vehicle is optimally aligned relative to the primary coil in the charging device. Each of the at least one vehicle-mounted receiver coil includes a clockwise winding loop and a counterclockwise winding loop that are substantially symmetrically configured and serially connected to each other. When the non-contacting position sensing apparatus is located directly above the primary coil of the charging device, the electromotive forces from the clockwise winding loop and the counterclockwise region cancel out to provide a zero electromotive force, i.e., a zero voltage reading across the coil that includes the clockwise winding loop and the counterclockwise winding loop.
1. A structure comprising a position sensing apparatus mounted on a vehicle, said position sensing apparatus comprising at least a receiver coil configured to generate a voltage in proportion to a net magnetic flux captured in a first loop and a second loop that are serially connected to each other, wherein one of said first loop and said second loop is wound clockwise and another of said first loop and second loop is wound counterclockwise, wherein said position sensing apparatus further comprises a vehicle alignment human-machine interface (HMI) configured to indicate a positional offset of said vehicle relative to a source of a magnetic field as calculated from a measurement on said voltage.
2. The structure of claim 1 , wherein an area of said first loop and an area of said second loop are substantially symmetric relative a vertical plane that pass through a geometrical center of said receiver coil.
3. The structure of claim 2 , wherein said vertical plane is parallel to a lengthwise direction of said vehicle.
4. The structure of claim 2 , wherein said vertical plane is parallel to a widthwise direction of said vehicle.
5. The structure of claim 1 , wherein said position sensing apparatus further comprises a second receiver coil configured to generate another voltage in proportion to a net magnetic flux captured in a third loop and a fourth loop that are serially connected to each other, wherein one of said third loop and said fourth loop is wound clockwise and another of said third loop and said fourth loop is wound counterclockwise.
6. The structure of claim 5 , wherein an area of said first loop and an area of said second loop are substantially symmetric about a first vertical plane that passes through a geometrical center of said receiver coil, and an area of said third loop and an area of said fourth loop are substantially symmetric about a second vertical plane that passes through said geometrical center of said second receiver coil.
7. The structure of claim 6 , wherein one of said first and second vertical planes is parallel to a lengthwise direction of said vehicle, and another of said first and second vertical planes is parallel to a widthwise direction of said vehicle.
8. The structure of claim 5 , further comprising a secondary coil mounted to said vehicle and connected to an on-board charger configured to charge a battery through wireless power transfer employing magnetic coupling of said secondary coil to a primary coil in a charging device located outside said vehicle, wherein no more than 10% of each area of said first, second, third, and fourth loops overlaps with areas of any other of said first, second, third, and fourth loops, and areas of said first, second, third, and fourth loops collectively overlap with more than 90% of an area of said secondary coil.
9. The structure of claim 2 , further comprising a secondary coil mounted to said vehicle and connected to an on-board charger configured to charge a battery through wireless power transfer employing magnetic coupling of said secondary coil to a primary coil in a charging device located outside said vehicle.
10. The structure of claim 9 , and wherein a geometrical center of said secondary coil is located along a vertical line that passes through said geometrical center of said receiver coil.
11. A structure comprising a position sensing apparatus mounted on a vehicle, said position sensing apparatus comprising at least a receiver coil configured to generate a voltage in proportion to a net magnetic flux captured in a first loop and a second loop that are serially connected to each other, wherein one of said first loop and said second loop is wound clockwise and another of said first loop and second loop is wound counterclockwise, wherein said position sensing apparatus further comprises a differential flux comparator that is connected to output nodes of said receiver coil and configured to rectify said voltage into a direct current (DC) voltage.
12. The structure of claim 11 , wherein said differential flux comparator comprises a first diode connected directly to a first output node of said receiver coil, a second diode connected directly to a second output node of said receiver coil, at least one capacitor connected across output nodes of said first and second diodes, at least one resistor connected across said output nodes of said first and second diodes, and a direct current voltmeter connected across said output nodes of said first and second diodes.