Wireless power transmission system

Patent metadata

Field	Value
Publication number	US-12224598-B2
Application number	US-202318232690-A
Country	US
Kind code	B2
Filing date	Aug 10, 2023
Priority date	Feb 25, 2021
Publication date	Feb 11, 2025
Grant date	Feb 11, 2025

Abstract

A wireless power transmission system is provided which wirelessly transfer electric power from a power transmitter to a power receiver. The wireless power transmission system works to set a capacitance of a primary capacitor of a primary resonant circuit to undergo resonance with a self-inductance of a primary coil at an angular frequency that is an operating frequency. A tertiary capacitor of a tertiary resonant circuit has a capacitance set to undergo resonance with a self-inductance of a tertiary coil. A secondary capacitor of a secondary resonant circuit has a capacitance set to reduce a reactive component of ac power arising from self-inductances and mutual inductances of the primary coil, the secondary coil, and the tertiary coil.

First claim

What is claimed is:

1. A wireless power transmission system which works to supply electric power wirelessly from a power transmitter to a power receiver, comprising:
a power transmitter which includes a primary resonant circuit and an alternating-current source, the primary resonant circuit including a primary coil and a primary capacitor for use in power transmission, the alternating-current source working to apply ac power at a given operating frequency to the primary resonant circuit;
a power receiver which includes a secondary resonant circuit, the secondary resonant circuit including a secondary coil and a secondary capacitor for use in a power reception, the secondary coil being to be magnetically coupled with the primary coil; and
a tertiary resonant circuit which includes a tertiary coil and a tertiary capacitor, the tertiary coil being arranged to achieve magnetic coupling with the primary coil and the secondary coil, the tertiary capacitor constituting a short-circuit resonant circuit along with the tertiary coil,
the primary coil has a self-inductance L1, a capacitance of the primary capacitor is set to a capacitance C1, as given by Eq. (1) below, to cause resonance in the primary capacitor and the primary coil at an angular frequency ω0 that is the operating frequency,

C
⁢
1

=

1

ω
⁢

o
2

·
L

⁢
1

(
1
)

the tertiary coil has a self-inductance L3, a capacitance of the tertiary capacitor is set to a capacitance C3, as given by Eq. (2) below, to cause resonance in the tertiary capacitor and the tertiary coil at the operating frequency,

C
⁢
3

=

1

ω
⁢

o
2

·
L

⁢
3

(
2
)

a capacitance of the secondary capacitor is determined to decrease a reactive component of the ac power which arises from the self-inductances and mutual inductances of the primary coil, the secondary coil, and the tertiary coil.

2. The wireless power transmission system as set forth in claim 1 , wherein the capacitance of the secondary capacitor is set to a value greater than a capacitance C2r given by Eq. (3) below expressed by the self-inductance L2 of the secondary coil and the angular frequency ω0,

C
⁢
2
⁢
r

=

1

ω
⁢

0
2

·
L

⁢
2

.

(
3
)

3. The wireless power transmission system as set forth in claim 2 , wherein the capacitance of the secondary capacitor is set to a capacitance C2 given by Eq. (4) below expressed by a self-inductance L2 of the secondary coil, a mutual inductance M12 of the primary coil and the secondary coil, a mutual inductance M13 of the primary coil and the tertiary coil, a mutual inductance M32 of the tertiary coil and the secondary coil, and the angular frequency ω0,

C
⁢
2

=

1

ω
⁢

0
2

[

L
⁢
2

-

2
·
M

⁢

12
·
M

⁢
32

M
⁢
13

]

.

(
4
)

4. The wireless power transmission system as set forth in claim 2 , wherein the capacitance of the secondary capacitor is set in a range of a value of the capacitance C2 and the value of the capacitance C2+25%, the value of the capacitance C2 being given by Eq. (4) below expressed by a self-inductan

Assignees

• Denso Corp

Inventors

• Takahashi Masaya
• Shibanuma Mitsuru
• Kato Kazuyuki
• NAKAYASHIKI Yusei
• Takahashi Eisuke
• Yamaguchi Nobuhisa

Classifications

• B60L53/39

  with position-responsive activation of primary coils · CPC title

• H02J50/40

  using two or more transmitting or receiving devices (H02J50/50 takes precedence) · CPC title

• H02J50/90

  involving detection or optimisation of position, e.g. alignment · CPC title

• B60L53/12

  Inductive energy transfer · CPC title

• H01F38/14

  Inductive couplings {(for wireless supply or distribution of electric power using inductive coupling H02J50/10)} · CPC title