POWER RECEIVING APPARATUS AND POWER RECEIVING METHOD

• US 20150188319A1
• Filed: 03/13/2012
• Published: 07/02/2015
• Est. Priority Date: 03/13/2012
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Pioneer Corporation
• Inventors: Iwawaki, Keisuke
• Granted Patent: US 9,935,468 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 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: H02M 3/02 without intermediate conversion into ac

Abstract

A power receiving apparatus (105) is provided with: a power reception unit (106) disposed at a distance from and opposed to a power transmission unit (104) of the power transmitting apparatus (101); a direct current (DC) voltage changing device (108) which constitutes one portion of a power receiving circuit configured to electrically connect the power reception unit and an electrical load (109) and which can change DC voltage supplied to the electrical load; and a controlling device (112) configured to control the DC voltage changing device to change the DC voltage to bring a current phase difference between current of the power transmission unit and current of the power reception unit close to 180 degrees when the electric power is transmitted and received between the power transmission unit and the power reception unit, the current phase difference corresponding to overall resonant frequency.

Claims

1. A power receiving apparatus configured to transmit and receive electric power in a wireless manner with a power transmitting apparatus, said power receiving apparatus comprising:

a power reception unit;

a direct current (DC) voltage changing device which electrically connects the power reception unit and an electrical load and which can change DC voltage supplied to the electrical load; and

a controlling device configured to control the DC voltage supplied from said DC voltage changing device to the electrical load to bring a current phase difference between current of a power transmission unit of the power transmitting apparatus and current of the power reception unit close to 180 degrees when the electric power is transmitted and received between the power transmission unit and the power reception unit.

2. The power receiving apparatus according to claim 1, wherein

the power receiving apparatus further comprises a capacitor which is electrically connected in series with the power reception unit,

said DC voltage changing device can change combined impedance between impedance associated with the electrical load and impedance associated with said DC voltage changing device, by changing the DC voltage, and

said controlling device controls said DC voltage changing device to change the combined impedance in a direction in which the combined impedance becomes less than excitation reactance associated with the power transmission unit and the power reception unit.

3. The power receiving apparatus according to claim 1, wherein

the power receiving apparatus further comprises a capacitor which is electrically connected in parallel with the power reception unit,

said DC voltage changing device can change combined impedance between impedance associated with the electrical load and impedance associated with said DC voltage changing device, by changing the DC voltage, and

said controlling device controls said DC voltage changing device to change the combined impedance in a direction in which the combined impedance becomes greater than excitation reactance associated with the power transmission unit and the power reception unit.

4. The power receiving apparatus according to claim 2, wherein

said controlling device includes an obtaining device configured to obtain power transmission side resonant frequency which is resonant frequency of alternating current power of the power transmitting apparatus, and

said controlling device obtains the excitation reactance on the basis of the power transmission side resonant frequency obtained by said obtaining device.

5. The power receiving apparatus according to claim 2, wherein

said controlling device includes an impedance detecting device configured to detect the impedance associated with the electrical load, and

said controlling device controls said DC voltage changing device to set the combined impedance within a predetermined range which is set in advance, on the basis of the detected impedance associated with the electrical load.

7. The power receiving apparatus according to claim 3, wherein

said controlling device includes an obtaining device configured to obtain power transmission side resonant frequency which is resonant frequency of alternating current power of the power transmitting apparatus, and

said controlling device obtains the excitation reactance on the basis of the power transmission side resonant frequency obtained by said obtaining device.

8. The power receiving apparatus according to claim 3, wherein

said controlling device includes an impedance detecting device configured to detect the impedance associated with the electrical load, and

said controlling device controls said DC voltage changing device to set the combined impedance within a predetermined range which is set in advance, on the basis of the detected impedance associated with the electrical load.

6. A power receiving method on a power receiving apparatus configured to transmit and receive electric power in a wireless manner with a power transmission unit of a power transmitting apparatus, said power receiving apparatus comprising:

a power reception unit; and

a direct current (DC) voltage changing device which electrically connects the power reception unit and an electrical load and which can change DC voltage supplied to the electrical load, said power receiving method comprising;

a controlling process of controlling the DC voltage supplied from said DC voltage changing device to the electrical load to bring a current phase difference between current of the power transmission unit and current of the power reception unit close to 180 degrees when the electric power is transmitted and received between the power transmission unit and the power reception unit.