Wireless power transmission device and wireless power transmission system
A wireless power transmission device capable of reducing an output power of wireless power receiving device receiving power transmitted from a wireless power transmission device. The wireless power transmission device including: a DC (Direct Current)/DC converter; an inverter configured to convert output voltage of the DC/DC converter into AC voltage having driving frequency; a power transmission coil configured for the AC voltage to be supplied to from the inverter and configured to generate the AC magnetic field; a transmission-side resonance circuit including the power transmission coil; and control circuit configured to increase difference between a driving frequency of the inverter and a resonance frequency of the transmission-side resonance circuit when a predetermined condition is satisfied.
1. A wireless power transmission device configured to transmit AC (Alternating Current) power to a wireless power receiving device including a power receiving coil by using an AC magnetic field, the wireless power transmission device comprising:
a DC (Direct Current)/DC converter;
an inverter configured to convert an output voltage of the DC/DC converter into an AC voltage having a driving frequency;
a power transmission coil configured for the AC voltage to be supplied to from the inverter and configured to generate the AC magnetic field;
a transmission-side resonance circuit including the power transmission coil; and
a control circuit configured to increase a difference between the driving frequency of the inverter and a resonance frequency of the transmission-side resonance circuit without decreasing the difference, when a predetermined condition is satisfied.
2. The wireless power transmission device according to claim 1 , wherein the control circuit is configured to change any one value of an output power, an output voltage, and an output current of the wireless power receiving device toward a predetermined value by increasing the difference between the driving frequency of the inverter and the resonance frequency of the transmission-side resonance circuit in a feedback control for changing the one value to be the predetermined value, when the predetermined condition is satisfied.
3. The wireless power transmission device according to claim 1 , wherein the predetermined condition is that the output voltage of the DC/DC converter is equal to or less than a predetermined first set voltage.
4. The wireless power transmission device according to claim 3 , wherein the first set voltage is the lowest value among voltages that can be output by the DC/DC converter.
5. The wireless power transmission device according to claim 3 , wherein the first set voltage is a voltage higher than the lowest value among voltages that can be output by the DC/DC converter and is a set voltage.
6. The wireless power transmission device according to claim 1 , wherein the predetermined condition is that a relation between a load voltage of a load connected to the wireless power receiving device and a load current of the load matches a predetermined relation.
7. The wireless power transmission device according to claim 1 , wherein the control circuit is configured to perform changing the output voltage of the DC/DC converter to a target voltage, when the predetermined condition is satisfied.
8. The wireless power transmission device according to claim 1 , wherein the control circuit is configured to control the driving frequency of the inverter and to control a phase difference time between an output voltage of the inverter and an output current of the inverter to be a predetermined phase difference time, when the predetermined condition is not satisfied.
9. The wireless power transmission device according to claim 1 , wherein the control circuit is configured to control the driving frequency of the inverter and to control a phase difference angle between an output voltage of the inverter and an output current of the inverter to be a predetermined phase difference angle, when the predetermined condition is not satisfied.
10. The wireless power transmission device according to claim 1 , wherein the control circuit causes the inverter to operate in a frequency band lower than 150 kHz, when the predetermined condition is not satisfied.
11. A wireless power transmission system comprising:
the wireless power transmission device according to claim 1 ; and
the wireless power receiving device.
12. A wireless power transmission device configured to transmit AC power to a wireless power receiving device including a power receiving-side resonance circuit including a power receiving coil by using an AC magnetic field, the wireless power transmission device comprising:
a DC/DC converter;
an inverter configured to convert an output voltage of the DC/DC converter into an AC voltage having a driving frequency;
a power transmission coil configured for the AC voltage to be supplied to from the inverter and configured to generate the AC magnetic field; and
a control circuit configured to increase a difference between the driving frequency of the inverter and a resonance frequency of the power receiving-side resonance circuit when a predetermined condition is satisfied.
13. The wireless power transmission device according to claim 12 , wherein the control circuit is configured to change any one value of an output power, an output voltage, and an output current of the wireless power receiving device toward a predetermined value by increasing the difference between the driving frequency of the inverter and the resonance frequency of the power receiving-side resonance circuit in a feedback control for changing the one value to be the predetermined value, when the predetermined condition is satisfied.
14. The wireless power transmission device according to claim 12 , wherein the predetermined condition is that the output voltage of the DC/DC converter is equal to or less than a predetermined first set voltage.
15. The wireless power transmission device according to claim 14 , wherein the first set voltage is the lowest value among voltages that can be output by the DC/DC converter.
16. The wireless power transmission device according to claim 14 , wherein the first set voltage is a voltage higher than the lowest value among voltages that can be output by the DC/DC converter and is a set voltage.
17. The wireless power transmission device according to claim 12 , wherein the predetermined condition is that a relation between a load voltage of a load connected to the wireless power receiving device and a load current of the load matches a predetermined relation.
18. The wireless power transmission device according to claim 12 , wherein the control circuit is configured to perform changing the output voltage of the DC/DC converter to a target voltage, when the predetermined condition is satisfied.
19. The wireless power transmission device according to claim 12 , wherein the control circuit is configured to control the driving frequency of the inverter and to control a phase difference time between an output voltage of the inverter and an output current of the inverter to be a predetermined phase difference time, when the predetermined condition is not satisfied.
20. The wireless power transmission device according to claim 12 , wherein the control circuit is configured to control the driving frequency of the inverter and to control a phase difference angle between an output voltage of the inverter and an output current of the inverter to be a predetermined phase difference angle, when the predetermined condition is not satisfied.
21. The wireless power transmission device according to claim 12 , wherein the control circuit causes the inverter to operate in a frequency band lower than 150 kHz, when the predetermined condition is not satisfied.
22. A wireless power transmission system comprising:
the wireless power transmission device according to claim 12 ; and
the wireless power receiving device.
23. A wireless power transmission device configured to transmit AC power to a wireless power receiving device including a power receiving coil by using an AC magnetic field, the wireless power transmission device comprising:
a DC/DC converter;
an inverter configured to convert an output voltage of the DC/DC converter into an AC voltage having a driving frequency;
a power transmission coil configured for the AC voltage to be supplied to from the inverter and configured to generate the AC magnetic field; and
a control circuit configured to perform intermittent operation control for intermittently operating the inverter when a predetermined condition is satisfied.
24. The wireless power transmission device according to claim 23 , wherein the predetermined condition is that the output voltage of the DC/DC converter is equal to or less than a predetermined first set voltage.
25. The wireless power transmission device according to claim 24 , wherein the first set voltage is the lowest value among voltages that can be output by the DC/DC converter.
26. The wireless power transmission device according to claim 24 , wherein the first set voltage is a voltage higher than the lowest value among voltages that can be output by the DC/DC converter and is a set voltage.
27. The wireless power transmission device according to claim 23 , wherein the predetermined condition is that a relation between a load voltage of a load connected to the wireless power receiving device and a load current of the load matches a predetermined relation.
28. The wireless power transmission device according to claim 23 , wherein the control circuit is configured to perform changing the output voltage of the DC/DC converter to a target voltage, when the predetermined condition is satisfied.
29. The wireless power transmission device according to claim 23 , wherein the control circuit is configured to control the driving frequency of the inverter and to control a phase difference time between an output voltage of the inverter and an output current of the inverter to be a predetermined phase difference time, when the predetermined condition is not satisfied.
30. The wireless power transmission device according to claim 23 , wherein the control circuit is configured to control the driving frequency of the inverter and to control a phase difference angle between an output voltage of the inverter and an output current of the inverter to be a predetermined phase difference angle, when the predetermined condition is not satisfied.
31. The wireless power transmission device according to claim 23 , wherein the control circuit causes the inverter to operate in a frequency band lower than 150 kHz, when the predetermined condition is not satisfied.
32. A wireless power transmission system comprising:
the wireless power transmission device according to claim 23 ; and
the wireless power receiving device.