Contactless power transmission device and power transfer system

• US 10,644,540 B2
• Filed: 06/07/2016
• Issued: 05/05/2020
• Est. Priority Date: 07/21/2015
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Misawa, Takahiro
• Primary Examiner(s): Perez Borroto, Alfonso
• Application Number:
  US15/175,482
• Publication Number:
  US 20170025898A1
• Time in Patent Office: 1,428 Days
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02M 1/0051 Diode reverse recovery losses
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• 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 power transmission device includes a power transmission unit and a voltage-source inverter. A power supply ECU executes turn-on current control for controlling a turn-on current It to a target current Itr by adjusting a drive frequency f of the inverter, turn-on current It indicating an output current of the inverter at a rising of an output voltage of the inverter. A first case is a case where transmission power Ps has a first value which is lower than target power Psr and a second case is a case where the transmission power has a second value which is closer to target power Psr than the first value. The power supply ECU makes a change rate of the drive frequency in the second case lower than in the first case.

Claims

1. A contactless power transmission device comprising:

a power transmission unit configured to transmit electric power to a power reception device in a contactless manner;

a voltage-source inverter configured to supply transmission power to the power transmission unit; and

a control unit configured to control the inverter,

the control unit configured to execute;

a first control for controlling the transmission power to target power by adjusting a duty of an output voltage of the inverter; and

a second control for controlling a turn-on current by adjusting a drive frequency of the inverter, the turn-on current indicating an output current of the inverter at a rising of the output voltage of the inverter,

a first case being a case where the transmission power has a first value which is lower than the target power in the second control and a second case being a case where the transmission power has a second value which is closer to the target power than the first value in the second control,

the control unit being configured to make a change rate of the drive frequency in the second case lower than in the first case.

2. The contactless power transmission device according to claim 1, wherein

when changing the drive frequency in the second control, a change amount of the drive frequency per one adjusting operation of the drive frequency is constant, and

a changing cycle of the drive frequency in the second case is longer than a changing cycle of the drive frequency in first case.

3. The contactless power transmission device according to claim 1, wherein

when changing the drive frequency in the second control, a changing cycle of the drive frequency is constant, and

a change amount of the drive frequency per one adjusting operation of the drive frequency in the second case is smaller than a change amount of the drive frequency per one adjusting operation of the drive frequency in the first case.

4. A power transfer system comprising:

a power transmission device; and

a power reception device,

the power transmission device including;

a power transmission unit configured to transmit electric power to the power reception device in a contactless manner;

a voltage-source inverter configured to supply transmission power to the power transmission unit; and

a control unit configured to control the inverter,

the control unit configured to execute;

a first control for controlling the transmission power to target power by adjusting a duty of an output voltage of the inverter; and

a second control for controlling a turn-on current by adjusting a drive frequency of the inverter, the turn-on current indicating an output current of the inverter at a rising of the output voltage of the inverter,

a first case being a case where the transmission power has a first value which is lower than the target power in the second control and a second case being a case where the transmission power has a second value which is closer to the target power than the first value in the second control,

the control unit being configured to make a change rate of the drive frequency in the second case lower than in the first case.

5. The power transfer system according to claim 4, wherein

when changing the drive frequency in the second control, a change amount of the drive frequency per one adjusting operation of the drive frequency is constant, and

a changing cycle of the drive frequency in the second case is longer than a changing cycle of the drive frequency in first case.

6. The power transfer system according to claim 4, wherein

when changing the drive frequency in the second control, a changing cycle of the drive frequency is constant, and

a change amount of the drive frequency per one adjusting operation of the drive frequency in the second case is smaller than a change amount of the drive frequency per one adjusting operation of the drive frequency in the first case.