POWER RECEIVER AND POWER TRANSMITTING SYSTEM

• US 20170346346A1
• Filed: 08/15/2017
• Published: 11/30/2017
• Est. Priority Date: 02/20/2015
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: SHIMOKAWA, SATOSHI
• Granted Patent: US 10,461,584 B2
• Time in Patent Office: Days
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• 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: H03L 7/085 concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal H03L7/10 takes precedence; circuits for comparing the phase or frequency of two mutually-independent oscillations H03D13/00

Abstract

A power receiver includes: a secondary-side resonant coil including a resonant coil part to receive electric power from a primary-side resonant coil through magnetic field resonance; a first capacitor inserted in series in the resonant coil part; a series circuit of a first switch and a second switch; a first rectifier having a first rectification direction; a second rectifier having a second rectification direction opposite to the first rectification direction; a second capacitor inserted in series with the series circuit; a detector configured to detect a voltage waveform or a current waveform of the electric power; and a controller configured to adjust a phase difference between the waveform and a driving signal that includes a first signal for switching on/off the first switch and a second signal for switching on/off the second switch to adjust an amount of the electric power received by the secondary-side resonant coil.

Claims

1. A power receiver comprising:

a secondary-side resonant coil including a resonant coil part and configured to receive electric power from a primary-side resonant coil through magnetic field resonance generated between the primary-side resonant coil and the secondary-side resonant coil;

a first capacitor inserted in series in the resonant coil part of the secondary-side resonant coil;

a series circuit, coupled in parallel with the first capacitor, of a first switch and a second switch;

a first rectifier coupled in parallel with the first switch, the first rectifier having a first rectification direction;

a second rectifier coupled in parallel with the second switch, the second rectifier having a second rectification direction opposite to the first rectification direction;

a second capacitor inserted in series with the series circuit;

a detector configured to detect a voltage waveform or a current waveform of the electric power supplied to the secondary-side resonant coil; and

a controller configured to adjust a phase difference between the voltage waveform or the current waveform detected by the detector and a driving signal that includes a first signal for switching on/off the first switch and includes a second signal for switching on/off the second switch to adjust an amount of the electric power received by the secondary-side resonant coil.

2. The power receiver according to claim 1, wherein the second capacitor is inserted in series between the resonant coil part and the first switch or between the first switch and the second switch.

3. The power receiver according to claim 1, wherein the second capacitor is inserted in series between the first switch and the second switch or between the second switch and the resonant coil part.

4. The power receiver according to claim 1,

wherein a first driving range, in which a phase of the driving signal, including the first signal and the second signal, is delayed with respect to a phase of the voltage waveform or the current waveform, differs from a second driving range, in which the phase of the driving signal, including the first signal and the second signal, is advanced with respect to the phase of the voltage waveform or the current waveform, in efficiency of electric power reception of the secondary-side resonant coil with respect to the phase difference, and

wherein the controller adjusts the phase difference in the first driving range to adjust the amount of the electric power received by the secondary-side resonant coil, a difference between a maximum value of the efficiency of electric power reception and a minimum value of the efficiency of electric power reception in the first driving range being greater than a difference between a maximum value of the efficiency of electric power reception and a minimum value of the efficiency of electric power reception in the second driving range.

5. The power receiver according to claim 1, wherein the controller adjusts the phase difference to adjust a ratio of a state, where resonance does not occur in the resonant coil part, to a state, where resonance occurs in the resonant coil part, to adjust the amount of the electric power received by the secondary-side resonant coil.

6. The power receiver according to claim 1,

wherein the secondary-side resonant coil further includes a first terminal and a second terminal provided at both ends of the resonant coil part, respectively,

wherein the first rectifier and the second rectifier respectively have a first current input terminal and a second current input terminal, and the first rectifier and the second rectifier are respectively coupled in parallel with the first switch and the second switch in a state where the first current input terminal and the second current input terminal are coupled, and

wherein the controller turns off the first switch and turns on the second switch when an electric current flows in the resonant coil part from the first terminal to the second terminal, and turns on the first switch and turns off the second switch when an electric current flows in the resonant coil part from the second terminal to the first terminal, to generate resonance in the resonant coil part through the magnetic field resonance.

7. The power receiver according to claim 6, wherein the controller turns on the first switch and turns off or on the second switch when an electric current flows in the resonant coil part from the first terminal to the second terminal, and turns off or on the first switch and turns on the second switch when an electric current flows in the resonant coil part from the second terminal to the first terminal, to generate a state where resonance does not occur in the resonant coil part through the magnetic resonance.

8. The power receiver according to claim 1, further comprising:

a communication part configured to receive a voltage waveform or a current waveform of electric power supplied to the primary-side resonant coil,

wherein the detector detects the voltage waveform or the current waveform of the electric power supplied to the secondary-side resonant coil, based on the voltage waveform or the current waveform of the electric power supplied to the primary-side resonant coil received by the communication part.

9. The power receiver according to claim 1, wherein the detector detects the voltage waveform or the current waveform of the electric power supplied to the secondary-side resonant coil.

10. The power receiver according to claim 1,

wherein the secondary-side resonant coil further includes a first terminal and a second terminal provided at both ends of the resonant coil part, respectively,

wherein the first rectifier and the second rectifier respectively have a first current output terminal and a second current output terminal, and the first rectifier and the second rectifier are respectively coupled in parallel with the first switch and the second switch in a state where the first current output terminal and the second current output terminal are coupled, and

wherein the controller turns on the first switch and turns off the second switch when an electric current flows in the resonant coil part from the first terminal to the second terminal, and turns off the first switch and turns on the second switch when an electric current flows in the resonant coil part from the second terminal to the first terminal, to generate resonance in the resonant coil part through the magnetic resonance.

11. The power receiver according to claim 10, wherein the controller turns off or on the first switch and turns on the second switch when an electric current flows in the resonant coil part from the first terminal to the second terminal, and turns on the first switch and turns off or on the second switch when an electric current flows in the resonant coil part from the second terminal to the first terminal, to generate a state where resonance does not occur in the resonant coil part through the magnetic resonance.

12. The power receiver according to claim 1, further comprising:

a rectifier circuit coupled to a first terminal and a second terminal of the secondary-side resonant coil and configured to rectify AC power input from the secondary-side resonant coil;

a smoothing circuit coupled to an output side of the rectifier circuit; and

a pair of output terminals coupled to an output side of the smoothing circuit.

13. A power transmitting system, comprising:

a power transmitter including a primary-side resonant coil and configured to transmit electric power; and

a first power receiver configured to receive the electric power from the power transmitter,

wherein the first power receiver includes

a first secondary-side resonant coil including a resonant coil part and configured to receive the electric power from the primary-side resonant coil through magnetic field resonance generated between the primary-side resonant coil and the first secondary-side resonant coil,

a first capacitor inserted in series in the resonant coil part of the first secondary-side resonant coil;

a series circuit, coupled in parallel with the first capacitor, of a first switch and a second switch,

a first rectifier coupled in parallel with the first switch, the first rectifier having a first rectification direction,

a second rectifier coupled in parallel with the second switch, the second rectifier having a second rectification direction opposite to the first rectification direction,

a detector configured to detect a voltage waveform or a current waveform of the electric power supplied to the first secondary-side resonant coil, and

a controller configured to adjust a phase difference between the voltage waveform or the current waveform detected by the detector and a driving signal that includes a first signal for switching on/off the first switch and includes a second signal for switching on/off the second switch to adjust an amount of the electric power received by the first secondary-side resonant coil.

14. The power transmitting system according to claim 13, further comprising:

a second power receiver including a second secondary-side resonant coil and configured to receive the electric power from the power transmitter,

wherein the controller sets the phase difference based on first efficiency of electric power reception of the first secondary-side resonant coil, on a first rated output of a first load to which the electric power is supplied from the first power receiver, on second efficiency of electric power reception of the second secondary-side resonant coil, and on a second rated output of a second load to which the electric power is supplied from the second power receiver.