Wireless power transfer terminal

• US 8,400,801 B2
• Filed: 10/25/2011
• Issued: 03/19/2013
• Est. Priority Date: 04/27/2009
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Manufacturing Co Limited
• Inventors: Shinoda, Satoshi
• Primary Examiner(s): Riley, Shawn
• Application Number:
  US13/281,133
• Publication Number:
  US 20120039102A1
• Time in Patent Office: 511 Days
• Field of Search: 363/16, 363/17, 363/123, 363/131
• US Class Current: 363/131
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• 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: Y02E 60/10 Energy storage using batteries

Abstract

This disclosure provides a wireless power transfer terminal that enables a power device to be used for both power transmission and power reception and allows space savings of circuits and a reduction in the cost of manufacturing. The wireless power transfer terminal includes first through fourth switching elements, a coil, and a control circuit. Each of two sets of switching elements forms a series circuit, and the two sets are connected in parallel to each other. The coil is connected between connection points of the switching elements of the series circuits. The control circuit performs switching control of the first to fourth switching elements in a power transmission mode and in a power reception mode.

Claims

1. A wireless power transfer terminal comprising:

a parallel circuit in which a first series circuit and a second series circuit are connected in parallel between opposed ends of the parallel circuit, the first series circuit including first and second semiconductor switching elements connected in series to each other, the second series circuit including third and fourth semiconductor switching elements connected in series to each other;

a coil connected between a connection point of the first semiconductor switching element and the second semiconductor switching element and a connection point of the third semiconductor switching element and the fourth semiconductor switching element; and

a control unit configured to perform switching control of at least the first to fourth semiconductor switching elements.

2. The wireless power transfer terminal according to claim 1, wherein the control unit is configured to perform switching control of at least the first to fourth semiconductor switching elements such that:

in a power transmission mode, the parallel circuit operates as a full-bridge inverter circuit that forms, from an input across the opposed ends of the parallel circuit, an alternating-current output to the coil, and

in a power reception mode, the parallel circuit operates as a full-wave rectifier circuit that forms, from an alternating-current input to the coil, an output to the opposed ends of the parallel circuit.

3. The wireless power transfer terminal according to claim 1, wherein:

in the power transmission mode, the control unit is configured to switch between a state in which the first semiconductor switching element and the fourth semiconductor switching element are on and the second semiconductor switching element and the third semiconductor switching element are off, and a state in which the first semiconductor switching element and the fourth semiconductor switching element are off and the second semiconductor switching element and the third semiconductor switching element are on at specific periods, and

in the power reception mode, the control unit is configured to turn off, of the first to fourth semiconductor switching elements, at least one of the first to fourth semiconductor switching elements that is connected to a terminal of a power reception load to which a positive voltage is applied and to a terminal of the coil at which a negative voltage is excited and one of the first to fourth semiconductor switching elements that is connected to a terminal of the power reception load to which a negative voltage is applied and to a terminal of the coil at which a positive voltage is excited.

4. The wireless power transfer terminal according to claim 2, wherein:

in the power transmission mode, the control unit is configured to switch between a state in which the first semiconductor switching element and the fourth semiconductor switching element are on and the second semiconductor switching element and the third semiconductor switching element are off, and a state in which the first semiconductor switching element and the fourth semiconductor switching element are off and the second semiconductor switching element and the third semiconductor switching element are on at specific periods, and

in the power reception mode, the control unit is configured to turn off, of the first to fourth semiconductor switching elements, at least one of the first to fourth semiconductor switching elements that is connected to a terminal of a power reception load to which a positive voltage is applied and to a terminal of the coil at which a negative voltage is excited and one of the first to fourth semiconductor switching elements that is connected to a terminal of the power reception load to which a negative voltage is applied and to a terminal of the coil at which a positive voltage is excited.

5. The wireless power transfer terminal according to claim 1, further comprising a resonant capacitor connected in series to the coil and a switch unit connected in parallel to the resonant capacitor,

wherein the control unit is configured to, for power transmission, turn off the switch unit and make the resonant capacitor resonate with the coil and, for power reception, turn on the switch unit and electrically bypass the resonant capacitor.

6. The wireless power transfer terminal according to claim 2, further comprising a resonant capacitor connected in series to the coil and a switch unit connected in parallel to the resonant capacitor,

wherein the control unit is configured to, for power transmission, turn off the switch unit and make the resonant capacitor resonate with the coil and, for power reception, turn on the switch unit and electrically bypass the resonant capacitor.

7. The wireless power transfer terminal according to claim 3, further comprising a resonant capacitor connected in series to the coil and a switch unit connected in parallel to the resonant capacitor,

wherein the control unit is configured to, for power transmission, turn off the switch unit and make the resonant capacitor resonate with the coil and, for power reception, turn on the switch unit and electrically bypass the resonant capacitor.

8. The wireless power transfer terminal according to claim 4, further comprising a resonant capacitor connected in series to the coil and a switch unit connected in parallel to the resonant capacitor,

wherein the control unit is configured to, for power transmission, turn off the switch unit and make the resonant capacitor resonate with the coil and, for power reception, turn on the switch unit and electrically bypass the resonant capacitor.

9. The wireless power transfer terminal according to claim 1, wherein each of the semiconductor switching elements is an FET element.

10. The wireless power transfer terminal according to claim 2, wherein each of the semiconductor switching elements is an FET element.

11. The wireless power transfer terminal according to claim 3, wherein each of the semiconductor switching elements is an FET element.

12. The wireless power transfer terminal according to claim 4, wherein each of the semiconductor switching elements is an FET element.

13. The wireless power transfer terminal according to claim 1, further comprising:

a rechargeable secondary cell; and

a buck-boost converter circuit configured to, in the power transmission mode, increase a voltage between opposed ends of the secondary cell and apply the increased voltage to the opposed ends of the parallel circuit and, in the power reception mode, decrease a voltage between the opposed ends of the parallel circuit and apply the decreased voltage to the opposed ends of the secondary cell.

14. The wireless power transfer terminal according to claim 2, further comprising:

a rechargeable secondary cell; and

a buck-boost converter circuit configured to, in the power transmission mode, increase a voltage between opposed ends of the secondary cell and apply the increased voltage to the opposed ends of the parallel circuit and, in the power reception mode, decrease a voltage between the opposed ends of the parallel circuit and apply the decreased voltage to the opposed ends of the secondary cell.

15. The wireless power transfer terminal according to claim 3, further comprising:

a rechargeable secondary cell; and

a buck-boost converter circuit configured to, in the power transmission mode, increase a voltage between opposed ends of the secondary cell and apply the increased voltage to the opposed ends of the parallel circuit and, in the power reception mode, decrease a voltage between the opposed ends of the parallel circuit and apply the decreased voltage to the opposed ends of the secondary cell.

16. The wireless power transfer terminal according to claim 4, further comprising:

a rechargeable secondary cell; and

a buck-boost converter circuit configured to, in the power transmission mode, increase a voltage between opposed ends of the secondary cell and apply the increased voltage to the opposed ends of the parallel circuit and, in the power reception mode, decrease a voltage between the opposed ends of the parallel circuit and apply the decreased voltage to the opposed ends of the secondary cell.

17. The wireless power transfer terminal according to claim 1, wherein the control unit is configured to carry out mutual device authentication communication with a partner device coupled to the coil and variably control transmitting power or received power according to the partner device.

18. The wireless power transfer terminal according to claim 2, wherein the control unit is configured to carry out mutual device authentication communication with a partner device coupled to the coil and variably control transmitting power or received power according to the partner device.

19. The wireless power transfer terminal according to claim 3, wherein the control unit is configured to carry out mutual device authentication communication with a partner device coupled to the coil and variably control transmitting power or received power according to the partner device.

20. The wireless power transfer terminal according to claim 4, wherein the control unit is configured to carry out mutual device authentication communication with a partner device coupled to the coil and variably control transmitting power or received power according to the partner device.