Contactless power transfer system and power transmission device

• US 10,263,472 B2
• Filed: 08/17/2016
• Issued: 04/16/2019
• Est. Priority Date: 08/28/2015
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Sugiyama, Yoshinobu, Minamii, Toshihiko
• Primary Examiner(s): Borroto, Alfonso Perez
• Assistant Examiner(s): Yeshaw, Esayas G
• Application Number:
  US15/239,610
• Publication Number:
  US 20170063161A1
• Time in Patent Office: 972 Days
• 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: H02H 3/023 by short-circuiting
• CPC Class Codes: H02H 3/20 responsive to excess voltage
• 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 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• 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 90/14 Plug-in electric vehicles

Abstract

A contactless power transfer system includes a power supply ECU configured to control an inverter to stop power transmission from a power transmission unit when a current generated in the power transmission unit exceeds a predetermined threshold value due to short-circuiting of a power reception coil. The power supply ECU estimates a coupling state between a power transmission coil and the power reception coil, and changes the predetermined threshold value in accordance with the estimated coupling state.

Claims

1. A contactless power transfer system for transferring electric power in a contactless manner between a power transmission device and a power reception device, the contactless power transfer system comprising:

a power transmission unit including a power transmission coil and configured to transmit electric power in a contactless manner;

a power reception unit including a power reception coil and configured to receive electric power from the power transmission unit in a contactless manner;

a protection circuit configured to short-circuit the power reception coil when an overvoltage occurs in the power reception device originating from power reception by the power reception unit, the power transmission unit being configured to generate a current in the power transmission unit when the power reception coil is short-circuited by the protection circuit; and

a control unit configured to control the power transmission unit to stop power transmission when the current generated in the power transmission unit exceeds a predetermined threshold value due to short-circuiting of the power reception coil,

the control unit being configured to estimate a coupling state between the power transmission coil and the power reception coil, and change the predetermined threshold value in accordance with the estimated coupling state.

2. The contactless power transfer system according to claim 1, further comprising first and second filters connected to the power transmission unit and the power reception unit, respectively, wherein

the predetermined threshold value is set previously in accordance with properties of the first and second filters.

4. The contactless power transfer system according to claim 1, further comprising first and second filters connected to the power transmission unit and the power reception unit, respectively, wherein

the control unit includes a memory storing a plurality of threshold value management tables associated with combination patterns of configurations of the first and second filters, and

the control unit is configured to select any one threshold value management table from among the plurality of threshold value management tables in accordance with a combination of configurations of the first and second filters to determine the predetermined threshold value using the selected threshold value management table and the estimated coupling state.

3. A power transmission device for transmitting electric power to a power reception device in a contactless manner,

the power reception device including:

a power reception unit including a power reception coil and configured to receive electric power in a contactless manner; and

a protection circuit configured to short-circuit the power reception coil when an overvoltage occurs in the power reception device originating from power reception by the power reception unit,

the power transmission device including;

a power transmission unit including a power transmission coil and configured to transmit electric power to the power reception unit in a contactless manner; and

a control unit,

the power transmission unit being configured to generate a current in the power transmission unit when the power reception coil is short-circuited by the protection circuit,

the control unit being configured to control the power transmission unit to stop power transmission when the current generated in the power transmission unit exceeds a predetermined threshold value due to short-circuiting of the power reception coil,

the control unit being configured to estimate a coupling state between the power transmission coil and the power reception coil, and change the predetermined threshold value in accordance with the estimated coupling state.

5. The power transmission device according to claim 3, wherein

the power transmission device includes a first filter connected to the power transmission unit,

the power reception device includes a second filter connected to the power reception unit,

the control unit includes a memory storing a plurality of threshold value management tables associated with combination patterns of configurations of the first and second filters, and

the control unit is configured to select any one threshold value management table from among the plurality of threshold value management tables in accordance with a combination of configurations of the first and second filters to determine the predetermined threshold value using the selected threshold value management table and the estimated coupling state.