WIRELESS POWER TRANSMISSION SYSTEM AND POWER TRANSMISSION DEVICE

• US 20160064951A1
• Filed: 11/09/2015
• Published: 03/03/2016
• Est. Priority Date: 07/31/2013
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: YAMAMOTO, HIROSHI, SAKATA, TSUTOMU, KANNO, HIROSHI, MATSUMOTO, HIROMU
• Granted Patent: US 9,991,748 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 50/20 using microwaves or radio frequency waves
• 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

Abstract

A power transmission device includes: an oscillator including first through fourth switching devices, and converting DC power into AC power by pulses supplied thereto; a power transmission antenna delivering the AC power to a load of a power receiving device; memory holding a predetermined value indicating at least one of required voltage, current, and power; a receiving circuit receiving information of at least one of voltage, current, and power, supplied to the load; and a control circuitry changing a phase difference Δθ between pulses supplied to the first and fourth switching devices, and between pulses supplied to the second and third switching devices, thereby changing voltage of the AC power, deciding frequency of AC power where efficiency is greatest, converging the at least one of voltage, current, and power, of which information has been received, to the predetermined value range, and outputting AC power where the efficiency is the greatest.

Claims

1. A power transmission device comprising:

an oscillator including four switching devices, which are a first switching device and a third switching device connected to a high-potential side of DC power supplied from a DC source and a second switching device and a fourth switching device connected to a low-potential side of the DC power, a first output end of the oscillator connected to a side of the first switching device opposite to the high-potential side being connected to a side of the second switching device opposite to the low-potential side and a second output end of the oscillator connected to a side of the third switching device opposite to the high-potential side being connected to a side of the fourth switching device opposite to the low-potential side, the oscillator converting the DC power into AC power by pulses supplied to each of the first through fourth switching devices via the first and second output terminals, and output the AC power;

a power transmission antenna that transmits the AC power output from the oscillator for output to a load of a power receiving device;

memory that holds a predetermined value indicating at least one of required voltage, required current, and required power, for the power receiving device;

a receiving circuit that receives information of at least one of voltage, current, and power, supplied to the load of the power receiving device; and

control circuitry operative to;

cause the oscillator to change a phase difference AO between pulses supplied to the first switching device and pulses supplied to the fourth switching device, and a phase difference AO between pulses supplied to the second switching device and pulses supplied to the third switching device, thereby changing voltage of the AC power output from the oscillator,

determine a frequency of AC power where efficiency of the AC power is greatest, by changing a frequency of the voltage of the AC power output from the oscillator, and

converge the at least one of voltage, current, and power, of which information has been received, to a range of the predetermined value, and outputs AC power where the efficiency is the greatest, to the load.

2. The power transmission device according to claim 1,

wherein the control circuitry supplies, at the leading edge of a pulse supplied to the second switching device, an inverted pulse of a pulse supplied to the first switching device, thereby providing a dead time where both the first switching device and the second switching device are off for a certain amount of time,

and supplies, at the leading edge of a pulse supplied to the third switching device, an inverted pulse of a pulse supplied to the fourth switching device, thereby providing a dead time where both the third switching device and the fourth switching device are off for a certain amount of time.

3. The power transmission device according to claim 1,

wherein, during a period where the phase difference Δ

θ

is occurring, the control circuitry instructs one of turning both the first switching device and the third switching device on at the same time, and turning both the second switching device and the fourth switching device on at the same time, using the oscillator.

4. The power transmission device according to claim 1,

wherein the control circuitry changes the frequency of the AC power output from the oscillator from high-frequency to low-frequency, and determines a frequency of the AC power where the efficiency of the AC power is greatest.

5. The power transmission device according to claim 4,

wherein the phase difference Δ

θ

that changes the voltage of the AC power output from the oscillator is changed, at the frequency of the AC power where the AC power at which the efficiency is greatest has been determined.

6. The power transmission device according to claim 1,

wherein the control circuitry changes the phase difference Δ

θ

that changes the voltage of the AC power and converges the voltage supplied to the load to the predetermined value, and thereafter changes the frequency of the voltage of the AC power and determines the frequency of the AC power where the efficiency of the AC power is greatest.

7. The power transmission device according to claim 1,

wherein the receiving circuit receives, from the power receiving device, error information indicating an error between at least one of voltage, current, and power of the AC power output to the load, and the predetermined value,

and wherein the control circuitry uses the error which the error information indicates to converge at least one of the voltage, current, and power, of which information has been received, to the range of the predetermined value.

8. A wireless power transmission system comprising:

a power transmission device including

four switching devices, which are an oscillator including a first switching device and a third switching device connected to a high-potential side of DC power supplied from a DC source and a second switching device and a fourth switching device connected to a low-potential side of the DC power, a first output end of the oscillator connected to a side of the first switching device opposite to the high-potential side being connected to a side of the second switching device opposite to the low-potential side and a second output end of the oscillator connected to a side of the third switching device opposite to the high-potential side being connected to a side of the fourth switching device opposite to the low-potential side, the oscillator converting the DC power into AC power by pulses supplied to each of the first through fourth switching devices via the first and second output terminals, and output the AC power,

a power transmission antenna that transmits the AC power output from the oscillator for output to a load of a power receiving device,

memory that holds a predetermined value indicating at least one of required voltage, required current, and required power, for the power receiving device,

a receiving circuit that receives information of at least one of voltage, current, and power, supplied to the load of the power receiving device, and

control circuitry operative to;

cause the oscillator to change a phase difference Δ

θ

between pulses supplied to the first switching device and pulses supplied to the fourth switching device, and a phase difference Δ

θ

between pulses supplied to the second switching device and pulses supplied to the third switching device, thereby changing voltage of the AC power output from the oscillator,

determine a frequency of AC power where efficiency of the AC power is greatest, by changing a frequency of the voltage of the AC power output from the oscillator, and

converge the at least one of voltage, current, and power, of which information has been received, to a range of the predetermined value; and

the power receiving device, and outputs AC power where the efficiency is the greatest, to the load.

9. A power transmission device comprising:

an oscillator including four switching devices, which are a first switching device and a third switching device connected to a high-potential side of DC power supplied from a DC source and a second switching device and a fourth switching device connected to a low-potential side of the DC power, a first output end of the oscillator connected to a side of the first switching device opposite to the high-potential side being connected to a side of the second switching device opposite to the low-potential side and a second output end of the oscillator connected to a side of the third switching device opposite to the high-potential side being connected to a side of the fourth switching device opposite to the low-potential side, the oscillator converting the DC power into AC power by pulses supplied to each of the first through fourth switching devices via the first and second output terminals, and output the AC power;

an input detection circuit that detects a current value of DC power supplied from the DC source to the oscillator;

a power transmission antenna that transmits the AC power output from the oscillator for output to a load of a power receiving device;

memory that holds a predetermined value indicating at least one of required voltage, required current, and required power, for the power receiving device;

a receiving circuit that continuously receives information of either one of voltage and current supplied to the load of the power receiving device; and

control circuitry operative to;

cause the oscillator to change a phase difference AO between pulses supplied to the first switching device and pulses supplied to the fourth switching device, and a phase difference AO between pulses supplied to the second switching device and pulses supplied to the third switching device, thereby changing voltage of the AC power output from the oscillator,

converge the one of the voltage and current, of which information is continuously received, to a range of the predetermined value, and determines a frequency of the AC power where the current value of the DC current supplied from the DC source to the oscillator is smallest, and

output AC power, having efficiency corresponding to a value obtained by dividing the required power by an AC power where the current value of the DC power is the smallest, to the load as AC power of which the efficiency is greatest.

10. The power transmission device according to claim 9,

wherein the control circuitry supplies, at the leading edge of a pulse supplied to the second switching device, an inverted pulse of a pulse supplied to the first switching device, thereby providing a dead time where both the first switching device and the second switching device are off for a certain amount of time,

and supplies, at the leading edge of a pulse supplied to the third switching device, an inverted pulse of a pulse supplied to the fourth switching device, thereby providing a dead time where both the third switching device and the fourth switching device are off for a certain amount of time.

11. The power transmission device according to claim 9,

wherein, during a period where the phase difference Δ

θ

is occurring, the control circuitry instructs one of turning both the first switching device and the third switching device on at the same time, and turning both the second switching device and the fourth switching device on at the same time, using the oscillator.

12. A wireless power transmission system comprising:

a power transmission device including

an oscillator including four switching devices, which are a first switching device and a third switching device connected to a high-potential side of DC power supplied from a DC source and a second switching device and a fourth switching device connected to a low-potential side of the DC power, a first output end of the oscillator connected to a side of the first switching device opposite to the high-potential side being connected to a side of the second switching device opposite to the low-potential side and a second output end of the oscillator connected to a side of the third switching device opposite to the high-potential side being connected to a side of the fourth switching device opposite to the low-potential side, the oscillator converting the DC power into AC power by pulses supplied to each of the first through fourth switching devices via the first and second output terminals, and output the AC power,

an input detection circuit that detects a current value of DC power supplied from the DC source to the oscillator,

a power transmission antenna that transmits the AC power output from the oscillator for output to a load of a power receiving device,

memory that holds a predetermined value indicating at least one of required voltage, required current, and required power, for the power receiving device,

a receiving circuit that continuously receives information of either one of voltage and current supplied to the load of the power receiving device, and

control circuitry operative to;

cause the oscillator to change a phase difference Δ

θ

between pulses supplied to the first switching device and pulses supplied to the fourth switching device, and a phase difference Δ

θ

between pulses supplied to the second switching device and pulses supplied to the third switching device, thereby changing voltage of the AC power output from the oscillator,

converge the one of the voltage and current, of which information is continuously received, to a range of the predetermined value, and determines a frequency of the AC power where the current value of the DC current supplied from the DC source to the oscillator is smallest, and

output AC power, having efficiency corresponding to a value obtained by dividing the required power by an AC power where the current value of the DC power is the smallest, to the load as AC power of which the efficiency is greatest; and

the power receiving device.