Noncontact power transmission system and power transmitting device

• US 20080231120A1
• Filed: 03/13/2008
• Published: 09/25/2008
• Est. Priority Date: 03/20/2007
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Jin, Mikimoto
• Granted Patent: US 7,923,870 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/00045 Authentication, i.e. circuits for checking compatibility between one component, e.g. a battery or a battery charger, and another component, e.g. a power source
• CPC Class Codes: H02J 7/025 using non-contact coupling, e.g. inductive, capacitive

Abstract

A noncontact power transmission system having a power transmitting device including a primary coil and a power receiving device including a secondary coil, the primary coil and the secondary coil being electromagnetically coupled to each other and the power transmitting device configured to transmit electric power to the power receiving device, wherein the secondary coil contains a magnetic substance, the power transmitting device has a feeding section for feeding power to the primary coil and a self inductance detection section for detecting a change in the self inductance of the primary coil immediately after starting the feeding to the primary coil, wherein a feeding operation of the feeding section immediately after starting the feeding is determined based on a detection result of the self inductance detection section.

Claims

1. A noncontact power transmission device comprising:

a power transmitting device including a primary coil; and

a power receiving device including a secondary coil, the primary coil and the secondary coil being electromagnetically coupled to each other and the power transmitting device configured to transmit electric power to the power receiving device,

the power transmitting device having;

a feeding section that feeds power to the primary coil; and

a self inductance detection section that detects a change of self inductance of the primary coil after starting a feeding to the primary coil,

a feeding operation of the feeding section after the starting being determined based on a detection result of the self inductance detection section.

2. The noncontact power transmission system according to claim 1,

the power transmission device further having a control section that controls the feeding section so as to stop the feeding from the feeding section when a detection value detected by the self inductance detection section is at or below a predetermined value and to continue the feeding from the feeding section when a detection value detected by the self inductance detection section is at or above the predetermined value.

3. The noncontact power transmission system according to claim 1,

the feeding section intermittently feeds electric power to the primary coil.

4. The noncontact power transmission system according to claim 1,

the primary coil and the secondary coil being flat coils,

on one plane of the secondary coil, a magnetic sheet being provided.

5. The noncontact power transmission system according to claim 4,

the magnetic sheet formed by an amorphous magnetic substance.

6. The noncontact power transmission system according to claim 1, the power receiving device being installed in a mobile phone.

7. A power transmitting device comprising:

a feeding circuit that feeds power to a coil; and

a detection circuit that detects a change of self inductance of the coil,

based on a detection result of the detection circuit, the feeding circuit feeding the power.

8. A noncontact power transmission system comprising, the power transmission device according to claim 7.