NON-CONTACT ELECTRIC POWER TRANSMISSION SYSTEM

• US 20140333153A1
• Filed: 07/30/2014
• Published: 11/13/2014
• Est. Priority Date: 02/01/2012
• Status: Abandoned Application

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Tanaka, Shingo, Nakagawa, Yuta
• Application Number:
  US14/446,867
• Publication Number:
  US 20140333153A1
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/22 Constructional details or arrangements of charging converters specially adapted for charging electric vehicles
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H03H 7/38 Impedance-matching networks
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

Disclosed is a non-contact electric power transmission system including a power feeding unit provided with a power feeding side coil to which electric power is supplied, a power receiving unit provided with a power receiving side coil electromagnetically coupled with the power feeding side coil, and a capacitor connected in parallel with at least one of the power feeding side coil and the power receiving side coil, a capacity of which is varied such that a resonance frequency of the resonance circuit when the power feeding side coil and the power receiving side coil are critically coupled in a predetermined coil-to-coil distance between the power feeding side coil and the power receiving side coil, and a resonance frequency of the resonance circuit when the power feeding side coil and the power receiving side coil are over-coupled in a distance shorter than the coil-to-coil distance are conformed.

Claims

1. A non-contact electric power transmission system comprising:

a power feeding unit provided with a power feeding side coil to which electric power is supplied;

a power receiving unit provided with a power receiving side coil electromagnetically coupled with the power feeding side coil;

a capacitor connected in parallel with at least one of the power feeding side coil and the power receiving side coil so as to compose a resonance circuit, a capacity of the capacitor being varied such that a resonance frequency of the resonance circuit when the power feeding side coil and the power receiving side coil are critically coupled in a predetermined coil-to-coil distance between the power feeding side coil and the power receiving side coil, and a resonance frequency of the resonance circuit when the power feeding side coil and the power receiving side coil are over-coupled in a distance shorter than the coil-to-coil distance are conformed, wherein the capacity of the capacitor is varied such that the resonance frequency of the resonance circuit when the power feeding side coil and the power receiving side coil are critically coupled in the predetermined coil-to-coil distance between the power feeding side coil and the power receiving side coil, and a lower resonance frequency of two resonance frequencies when the power feeding side coil and the power receiving side coil are over-coupled to include the two resonance frequencies in a distance shorter than the coil-to-coil distance are conformed;

a distance measuring unit measuring the coil-to-coil distance between the power feeding side coil and the power receiving side coil;

a first memory in which the coil-to-coil distance measured by the distance measuring unit is stored;

a second memory in which a table including a relationship between the coil-to-coil distance and the capacity of the power feeding side capacitor is preliminarily stored; and

a controller reading the capacity of the power feeding side capacitor corresponding to the coil-to-coil distance obtained from the table, and then control a voltage-variable power source such that the capacity of the power feeding side capacitor conforms with the read capacity.

2. The non-contact electric power transmission system according to claim 1, the table covers the distance of 2 to 16 mm when the resonance frequency is 1 MHz.

3. The non-contact electric power transmission system according to claim 1, the table covers the distance of 2 to 8 mm when the resonance frequency is 1.8 MHz.