Power feeding coil unit and wireless power transmission device
A power feeding coil unit includes a power feeding coil, and first and second auxiliary coils arranged so that a wire of the first auxiliary coil and a wire of the second auxiliary coil do not overlap a wire of the a power feeding coil when viewed from a direction perpendicular to an axial direction of the power feeding coil. A direction of circulation of a magnetic flux generated by the first auxiliary coil and a magnetic flux generated by the second auxiliary coil are opposite to a direction of circulation of a magnetic flux generated by the power feeding coil. An axes of the first and second auxiliary coils are substantially perpendicular to a power feeding direction of the power feeding coil, and are not aligned with the axis of the power feeding coil.
1. A power feeding coil unit for wirelessly feeding power, comprising:
a power feeding coil having a wire wound in a helical shape; and
a first auxiliary coil and a second auxiliary coil, each of the first auxiliary coil and the second auxiliary coil having a wire wound in a helical shape, wherein
the first auxiliary coil and the second auxiliary coil are arranged so that the wire of the first auxiliary coil and the wire of the second auxiliary coil do not overlap the wire of the power feeding coil when viewed from a direction perpendicular to an axial direction of the power feeding coil,
a direction of circulation of a magnetic flux generated by the first auxiliary coil and a magnetic flux generated by the second auxiliary coil are opposite to a direction of circulation of a magnetic flux generated by the power feeding coil, and
an axis of the first auxiliary coil and an axis of the second auxiliary coil are nonparallel to a power feeding direction of the power feeding coil, and are not aligned with an axis of the power feeding coil.
2. The power feeding coil unit according to claim 1 , wherein
the axis of the first auxiliary coil and the axis of the second auxiliary coil are substantially perpendicular to the power feeding direction of the power feeding coil.
3. The power feeding coil unit according to claim 1 , wherein
the first auxiliary coil and the second auxiliary coil are located on a rear side of the power feeding coil.
4. The power feeding coil unit according to claim 1 , wherein
the power feeding coil includes a magnetic core, and each of the first auxiliary coil and the second auxiliary coil includes a magnetic core,
the magnetic core of the first auxiliary coil is coupled to the magnetic core of the power feeding coil, and
the magnetic core of the second auxiliary coil is coupled to the magnetic core of the power feeding coil.