Contactless power transmitting system and contactless charging system

• US 6,697,272 B2
• Filed: 03/06/2002
• Issued: 02/24/2004
• Est. Priority Date: 03/09/2001
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Nanbu, Takafumi, Koshiyama, Atsushi
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US10/091,987
• Publication Number:
  US 20020141208A1
• Time in Patent Office: 720 Days
• Field of Search: 363/37, 363/39, 363/41, 363/97, 363/98, 363/95, 363/40, 363/25, 363/26, 363/131, 363/15, 363/16, 363/17
• US Class Current: 363/97
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02M 3/338 in a self-oscillating arrangement H02M3/337 takes precedence
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A contactless power transmitting system includes a power transmitting circuit and a power receiving circuit that are coupled by a transformer having a primary coil and a secondary coil. The power transmitting circuit includes a switching power supply having a predetermined frequency. The power receiving circuit includes a capacitor that is connected to the secondary coil and that constitutes a resonating circuit in cooperation with the leakage inductance of the secondary coil and a flyback rectifier circuit. The capacitance of the capacitor is set so that the resonant frequency of the resonating circuit is substantially equal to the predetermined frequency of the switching power supply.

Claims

1. A contactless power transmitting system comprising:

a power transmitting circuit and a power receiving circuit inductively coupled by a two-piece transformer having a primary coil and a separate, spaced-apart secondary coil that can be separated from said primary coil,

said power transmitting circuit including;

a switching power supply having a predetermined frequency, and

said power receiving circuit including;

a capacitor connected to the secondary coil so as to form a secondary resonating circuit in cooperation with a leakage inductance of the secondary coil; and

a flyback rectifier circuit,

wherein a capacitance of the capacitor is set so that a resonant frequency of the secondary resonating circuit is substantially equal to the predetermined frequency of the switching power supply.

3. The contactless power transmitting system according to claim 1, wherein a turns ratio of the primary coil to the secondary coil of the transformer is set so that a difference between the resonant frequency of the secondary resonating circuit when a load is connected to the rectifier circuit and the resonant frequency of the secondary resonating circuit when the load is not connected thereto is large.

2. A contactless charging system comprising:

a power transmitting circuit and a power receiving circuit inductively coupled by a two-piece transformer having a primary coil and a separate, spaced-apart secondary coil that can be separated from said primary coil,

said power transmitting circuit including;

a switching power supply having a predetermined frequency, and

said power receiving circuit including;

a capacitor connected to the secondary coil so as to form a secondary resonating circuit in cooperation with a leakage inductance of the secondary coil; and

a flyback rectifier circuit for connection to a rechargeable battery,

wherein a capacitance of the capacitor is set so that a resonant frequency of the secondary resonating circuit is substantially equal to the predetermined frequency of the switching power supply.

4. The contactless charging system according to claim 2, wherein a turns ratio of the primary coil to the secondary coil of the transformer is set so that a difference between the resonant frequency of the secondary resonating circuit when the rechargeable battery is connected to the rectifier circuit and the resonant frequency of the secondary resonating circuit when the rechargeable battery is not connected thereto is large.