Excitation-quadrature-quadrature transmitter wireless power transfer system

Patent metadata

Field	Value
Publication number	US-12272971-B2
Application number	US-202218275746-A
Country	US
Kind code	B2
Filing date	Feb 9, 2022
Priority date	Feb 9, 2021
Publication date	Apr 8, 2025
Grant date	Apr 8, 2025

Abstract

There is described a wireless power transfer system utilizing a new excitation-quadrature-quadrature transmitter pad which includes one excitation coil and at least two decoupled quadrature auxiliary coils. A described resonant tank design method is proposed for constant-current charging and zero phase angle conditions. When there is a lateral misalignment in the receiver pad, the auxiliary coil that is better coupled with the receiver pad conducts more current than the more distant auxiliary coil does, reducing the leakage magnetic field in the surrounding area and/or improving transmission efficiency.

First claim

What is claimed is:

1. A wireless charging system adapted for lateral misalignment tolerance, the wireless charging system comprising:
a transmitter pad, the transmitter pad including:
an excitation coil coupled to a power source;
a first auxiliary charging coil inductively coupled to the excitation coil and not physically coupled to the power source, the first auxiliary charging coil has a larger surface area than the excitation coil and is positioned at a first height relative to the excitation coil having a corresponding midpoint offset relative to a midpoint of the excitation coil; and
a second auxiliary charging coil inductively coupled to the excitation coil and not physically coupled to the power source, the second auxiliary charging coil has a larger surface area than the excitation coil and is positioned at a second height relative to the excitation coil having a corresponding midpoint offset relative to the midpoint of the excitation coil, the second auxiliary charging coil overlaps with the first auxiliary charging coil relative to a plane of the excitation coil, the overlap relative to the plane of the excitation coil inductively decouples the first and second auxiliary charring coils;
a first auxiliary tank, comprising the first auxiliary charging coil and at least one or more first auxiliary charging coil compensation capacitors;
a second auxiliary tank, comprising the second auxiliary charging coil and at least one or more second auxiliary charging coil compensation capacitors, the second auxiliary tank has a matching impedance with the first auxiliary tank, due to the compensation of the first and second auxiliary compensation capacitors, so that the first and second auxiliary tanks are electrically symmetrical along a horizontal plane with respect to the midpoint of the excitation coil;

a receiver pad magnetically coupled to the first auxiliary charging coil and the second auxiliary charming coil, and laterally misaligned with the midpoint of the excitation coil the first auxiliary charging coil and the second auxiliary charging coil together project a magnetic flux to interface with the receiver pad;
wherein the at least one or more first auxiliary charging coil compensation capacitors and the at least one or more second auxiliary charging coil compensation capacitors have corresponding variable and selectable capacitances that are selected to, free of active control of the capacitors, maintain a substantially zero phase angle (ZPA) condition between an excitation voltage and an excitation current during interfacing with the receiver pad such that the projected magnetic flux is effectively steered in a direction of the receiver pad through an automatic biasing of current distribution in the first auxiliary charging coil and the second auxiliary charging coil towards the auxiliary charging coil which is nearest to the receiver pad to reduce leakage magnetic flux from the auxiliary charging coil which is farthest from the receiver pad.

2. The wireless charging system of claim 1 , wherein the first auxiliary charging coil and the second auxiliary charging coil are substantially symmetrical in displacement with respect to a centroid of the excitation coil.

3. The wireless charging system of claim 1 , wherein the first auxiliary charging coil and the second auxiliary charging coil are substantially symmetrical in displacement displaced along a horizontal plane with respect to the midpoint of the excitation coil.

4. The wireless charging system of claim 1 , wherein the impedance of the first auxiliary coil tank and the impedance of the second auxiliary coil tank are obtained by the equation:

❘
"\[LeftBracketingBar]"

Z
cc

(

X

a
⁢
1

)

❘
"\[RightBracketingBar]"

=

(

X

ar
⁢
1

⁢

X

ta
⁢
1

+

X

ar
⁢
2

⁢

X

ta
⁢
2

)

2

X

a
⁢
1

2

⁢

R
E

=

U
in
2

P
in

.

where X ar1 and X ar2 are impedances of the mutual inductances between the first and second auxiliary charging coils and the receiver pad; X ar1 is the equivalent impedance of the first auxiliary charging coil; Z′ cc is a total input impedance from the transmitter pad; R E is the equivalent resistance; X ta1 and X ta2 are impedances of the mutual inductances between the first and second auxiliary charging coils and the excitation coil; P in is a desired rated input power of the system ad U in is an input voltage to the system.

5. The wireless charging system of claim 1 , wherein the first auxiliary charging coil and the second auxiliary charging coil are adapted for maintaining constant charging conditions simultaneously with maintaining the ZPA condition.

6. The wireless charging system of claim 1 , further including magnetic shielding layers, wherein the corresponding capacitances are selected after accounting for the impact on a mutual coupling of the magnetic shielding layers.

7. The wireless charging system of claim 1 , wherein establishing the ZPA condition causes corresponding current distributions in the first auxiliary charging coil and the second auxiliary charging coil to adjust autonomously according to the lateral misalignment.

Assignees

• Governing Council Univ Toronto
• Eleappower Ltd
• Innovations & Partnerships Office Univ Of Toronto

Inventors

• Luo Zhichao
• Nie Shuang
• Pathmanathan Mehanathan
• Lehn Peter Waldemar

Classifications

• H02J50/402 Primary

  the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas · CPC title

• B60L53/122

  Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil · CPC title

• B60L53/39

  with position-responsive activation of primary coils · CPC title

• H02J50/12

  of the resonant type · CPC title

• Y02T90/14

  Plug-in electric vehicles · CPC title