Multi-coil placement method for power transmitter in wireless charging system
A multi-coil placement method of a wireless charging system is disclosed. The method may include obtaining a width parameter of an effective charging area a and a width parameter of a power transmitter coil b, calculating a ratio of the width parameters a/b, determining a shape, size and number of layers of mesh cells based on the ratio of a/b, determining a layout of the mesh cells, covering a required charging area using the mesh cells based on the determined shape, size, number of layers, and layout, and replacing the mesh cells with the power transmitter coils.
1. A method for placing power transmitter coils in a wireless charging system, comprising:
obtaining a width parameter of an effective charging area a and a width parameter of a power transmitter coil b;
calculating a ratio of the width parameters a/b;
determining a shape, size and number of layers of mesh cells based on the ratio of a/b;
determining a layout of the mesh cells;
covering a required charging area using the mesh cells based on the determined shape, size, number of layers, and layout; and
replacing the mesh cells with the power transmitter coils.
2. The method of claim 1 , wherein the mesh cells have an equilateral triangle shape.
3. The method of claim 1 , wherein the mesh cells have a square shape.
4. The method of claim 1 , wherein each mesh cell has a center, and replacing the mesh cells with the power transmitter coils comprises placing centers of the power transmitter coils at the centers of the mesh cells.
5. The method of claim 1 , wherein:
if
a
b
≥
2
,
determining a shape, size and number of layers of mesh cells based on the ratio of a/b comprises determining the mesh cells each having a square shape with a length parameter w, where, w≤√{square root over (2)}a, and mesh cells having one layer;
if
2
3
≤
a
b
<
2
,
determining the shape, size and number of layers of mesh cells based on the ratio of a/b comprises determining the mesh cells each having a triangle shape with the length parameter w, where, w≤√{square root over (3)}a, and mesh cells having one layer;
if
1
≤
a
b
<
2
3
,
determining the shape, size and number of layers of mesh cells based on the ratio of a/b comprises determining the mesh cells each having a square shape with the length parameter w, where, w≤√{square root over (2)}a, and mesh cells having two layers; and
if
2
3
≤
a
b
<
1
,
determining the shape, size and number of layers of mesh cells based on the ratio of a/b comprises determining the mesh cells each having a triangle shape with the length parameter w, where, w≤√{square root over (3)}a, and mesh cells having three layers.
6. The method of claim 5 , wherein the distance between the centers of two adjacent power transmitter coils is w.
7. The method of claim 1 , wherein the power transmitter coil has a circular shape and the width parameter b is the radius of the power transmitter coil.
8. The method of claim 1 , wherein the power transmitter coil has a square shape and the width parameter b is a half of the length of a side of the power transmitter coil.
9. The method of claim 1 , wherein the effective charging area is a circle, and the width parameter a is the radius of the effective charging area.
10. The method of claim 1 , wherein the effective charging area is a charging area of a power transmitter coil, where if a center of a power receiver coil is placed inside of the area, a coil-to-coil efficiency is not less than a pre-determined value.
11. The method of claim 10 , wherein the coil-to-coil efficiency is calculated by the ratio of the power receiver coil output power over the power transmitter coil input power.
12. The method of claim 10 , wherein the pre-determined value is 90%.
13. The method of claim 1 , wherein the width parameter a is a maximum horizontal distance between a center of a power transmitter coil and a center of a power receiver coil, within which, the coil-to-coil efficiency is not less than a predetermined value.
14. The method of claim 13 , wherein the coil-to-coil efficiency is calculated by the ratio of the power receiver coil output power over the power transmitter coil input power.
15. The method of claim 13 , wherein the pre-determined value is 90%.
16. A wireless charging system, comprising:
a charging area;
a plurality of power transmitter coils placed to cover the charging area, each power transmitter coil having an effective charging area, wherein:
a indicates a radius of the effective charging area and b indicates a half of a width of the power transmitter coil,
if
a
b
≥
2
,
the plurality of power transmitter coils are placed on one layer and centers of adjacent power transmitter coils are spaced with a length parameter w, where, w≤√{square root over (2)}a, and centers of adjacent four power transmitter coils form a square;
if
2
3
≤
a
b
<
2
,
the plurality of power transmitter coils are placed on one layer and centers of adjacent power transmitter coils are spaced with a length parameter w, where, w≤√{square root over (3)}a, and centers of adjacent three power transmitter coils form an equilateral triangle;
if
1
≤
a
b
<
2
3
,
the plurality or power transmitter coils are placed on two layers and on each layer, centers of adjacent power transmitter coils are spaced with a length parameter w, where, w≤√{square root over (2)}a, and, on each layer, centers of adjacent four power transmitter coils form a square, and each of the power transmitter coils on the second layer is placed in a central area of the square formed by the centers of adjacent four power transmitter coils on the first layer; and
if
2
3
≤
a
b
<
1
,
the plurality of power transmitter coils are placed on three layers and, on each layer, centers of adjacent power transmitter coils are spaced with a length parameter w, where, w≤√{square root over (3)}a, and, on each layer, centers of adjacent three power transmitter coils form an equilateral triangle, and each of the power transmitter coils on the third layer is placed in a central area of the equilateral triangle formed by the centers of the power transmitter coils on the second layer, each of the power transmitter coils on the second layer is placed in a central area of the equilateral triangle formed by the centers of the power transmitter coils on the first layer.
17. A wireless charging system, comprising:
a charging area;
a plurality of power transmitter coils placed to cover the charging area, each power transmitter coil having an effective charging area, wherein:
a indicates a radius of the effective charging area and b indicates a half of a width of the power transmitter coil,
centers of power transmitter coils are spaced with a distance w,
if
a
b
≥
2
,
w
≤
2
a
;
if
2
3
≤
a
b
<
2
,
w
≤
3
a
;
if
1
≤
a
b
<
2
3
,
w
≤
2
a
;
and
if
2
3
≤
a
b
<
1
,
w
≤
3
a
.
18. A wireless charging system, comprising:
a charging area; and
a plurality of power transmitter coils placed on two layers to cover the charging area, each power transmitter coil having an effective charging area, wherein:
a indicates a radius of the effective charging area and b indicates a half of a width of the power transmitter coil,
centers of adjacent power transmitter coils in a same layer are spaced with a distance
if
a
b
≥
2
,
w
≤
2
a
;
if
2
3
≤
a
b
<
2
,
w
≤
3
a
;
if
1
≤
a
b
<
2
3
,
w
≤
2
a
;
and
if
2
3
≤
a
b
<
1
,
w
≤
3
a
,
wherein centers of every three adjacent power transmitter coils on each layer form an equilateral triangle, and
each of the power transmitter coils on the second layer is placed in a central area of the triangle formed by the centers of adjacent three power transmitter coils on the first layer.
19. The system of claim 18 , further comprising a third layer of power transmitter coils on the second layer, centers of adjacent three power transmitter coils form an equilateral triangle on each layer, and each of the power transmitter coils on the third layer is placed in a central area of the equilateral triangle formed by the centers of the power transmitter coils on the second layer.
20. A wireless charging system, comprising:
a charging area; and
a plurality of power transmitter coils placed on two layers to cover the charging area, each power transmitter coil having an effective charging area, wherein:
a indicates a radius of the effective charging area and b indicates a half of a width of the power transmitter coil,
centers of adjacent power transmitter coils in a same layer are spaced with a distance w,
if
a
b
≥
2
,
w
≤
2
a
;
if
2
3
≤
a
b
<
2
,
w
≤
3
a
;
if
1
≤
a
b
<
2
3
,
w
≤
2
a
;
and
if
2
3
≤
a
b
<
1
,
w
≤
3
a
,
wherein centers of every four adjacent power transmitter coils on each layer form a square, and
each of the power transmitter coils on the second layer is placed in a central area of the square formed by the centers of adjacent four power transmitter coils on the first layer.