Transmitter-side control of wireless power transfer systems without using mutual coupling information or wireless feedback
Wireless power transfer systems and methods are provided. No wireless communication system is necessary feedback output information from the receiver side to the transmitter side. Nor is any knowledge of the mutual coupling or mutual inductance between the transmitter side and the receiver side required. A system can include an intermediate capacitor in the receiver circuit as a power flow indicator and hysteresis on-off switching actions of a decoupling power switch in the receiver circuit to regulate the DC voltage of the intermediate capacitor (for voltage-control) and the load current (for current-control) at a rated value within a narrow tolerance band. The turn-on and turn-off times of the decoupling switch in the receiver circuit can be detected in the transmitter circuit from, for example, the primary winding current or voltage. This can be used to meet the power demand in the receiver circuit dynamically.
1. A wireless power transfer (WPT) system, comprising:
a transmitter circuit comprising a transmitter winding; and
a receiver circuit comprising a receiver winding, an intermediate capacitor, and a decoupling switch,
wherein energy is transferred wirelessly through magnetic coupling of magnetic flux between the transmitter winding and the receiver winding, and
wherein the system implements transmitter-side input power control and receiver-side output power control without using any information about mutual inductance or mutual coupling factor between the transmitter circuit and the receiver circuit.
2. The WPT system according to claim 1 , wherein the receiver-side output power control is implemented using a voltage of the intermediate capacitor as an indicator for power flow control, and
wherein the decoupling switch is used as a control mechanism to regulate the voltage of the intermediate capacitor at a nominal value within a tolerance.
3. The WPT system according to claim 1 , wherein the receiver-side output power control is implemented using an output current to a load of the receiver circuit, and
wherein the decoupling switch is used as a control mechanism to regulate the output current to the load of the receiver circuit at a nominal value within a tolerance.
4. The WPT system according to claim 1 , wherein the transmitter-side input power control detects charging times and discharging times of the intermediate capacitor of the receiver circuit by detecting at least one electric variable in the transmitter circuit.
5. The WPT system according to claim 4 , wherein the at least one electric variable in the transmitter circuit comprises the magnitude of a current of the transmitter winding, the magnitude of a voltage of the transmitter winding, or both.
6. The WPT system according to claim 4 , wherein the detected charging times and discharging times are used to derive a control signal for closed-loop control on the transmitter side to control the input power.
7. The WPT system according to claim 6 , wherein the input power is controlled to dynamically meet the output power or load demand on the receiver side.
8. The WPT system according to claim 1 , wherein the receiver-side output power control uses hysteresis control to regulate the voltage of the intermediate capacitor to a nominal value within a tolerance or a hysteresis band.
9. The WPT system according to claim 1 , wherein the decoupling switch of the receiver circuit is configured to periodically decouple or isolate a load from receiving power directly from the receiver winding.
10. The WPT system according to claim 1 , wherein a load connected to the receiver circuit receives power stored in the intermediate capacitor when the decoupling switch of the receiver circuit is activated, thereby discharging the intermediate capacitor when the load receives the power stored in the intermediate capacitor.
11. The WPT system according to claim 1 , wherein the decoupling switch of the receiver circuit is a shunt decoupling switch or is a series decoupling switch.
12. The WPT system according to any of claims 1 , wherein the transmitter-side input power control uses a control variable to control the input power to the transmitter circuit.
13. The WPT system according to claim 12 , wherein the control variable comprises at least one of a phase-shift angle of an output voltage, a frequency of the output voltage, the magnitude of the output voltage, the magnitude of an output current, and a DC link voltage.
14. The WPT system according to any of claims 1 , wherein the transmitter-side input power control and the receiver-side output power control are implemented in analog form, digital form, or a combination thereof.
15. The WPT system according to claim 1 , wherein the transmitter winding is a transmitter coil and/or the receiver winding is a receiver coil.
16. The WPT system according to claim 1 , wherein the system implements transmitter-side input power control and receiver-side output power control without any wireless communication circuit between the transmitter circuit and the receiver circuit providing feedback control.
17. The WPT system according to claim 16 , wherein the receiver-side output power control is implemented using a voltage of the intermediate capacitor as an indicator for power flow control, and
wherein the decoupling switch is used as a control mechanism to regulate the voltage of the intermediate capacitor at a nominal value within a tolerance.
18. The WPT system according to claim 16 , wherein the receiver-side output power control is implemented using an output current to a load of the receiver circuit, and
wherein the decoupling switch is used as a control mechanism to regulate the output current to the load of the receiver circuit at a nominal value within a tolerance.
19. The WPT system according to claim 16 , wherein the transmitter-side input power control detects charging times and discharging times of the intermediate capacitor of the receiver circuit by detecting at least one electric variable in the transmitter circuit.
20. The WPT system according to claim 16 , wherein the receiver-side output power control uses hysteresis control to regulate the voltage of the intermediate capacitor to a nominal value within a tolerance or a hysteresis band.
21. The WPT system according to claim 16 , wherein the decoupling switch of the receiver circuit is configured to periodically decouple or isolate a load from receiving power directly from the receiver winding.
22. The WPT system according to claim 16 , wherein a load connected to the receiver circuit receives power stored in the intermediate capacitor when the decoupling switch of the receiver circuit is activated, thereby discharging the intermediate capacitor when the load receives the power stored in the intermediate capacitor.
23. The WPT system according to claim 16 , wherein the decoupling switch of the receiver circuit is a shunt decoupling switch or is a series decoupling switch.
24. The WPT system according to claim 16 , wherein the transmitter-side input power control uses a control variable to control the input power to the transmitter circuit.
25. The WPT system according to claim 16 wherein the transmitter-side input power control and the receiver-side output power control are implemented in analog form, digital form, or a combination thereof.
26. The WPT system according to claim 16 , wherein the transmitter winding is a transmitter coil and/or the receiver winding is a receiver coil.
27. A wireless power transfer (WPT) control method for a WPT system comprising: a transmitter circuit comprising a transmitter winding; and a receiver circuit comprising
a receiver winding, an intermediate capacitor, and a decoupling switch, wherein the method comprises:
transferring energy wirelessly through magnetic coupling of magnetic flux between the transmitter winding and the receiver winding; and
implementing transmitter-side input power control and receiver-side output power control without using any information about mutual inductance between the transmitter circuit and the receiver circuit and without any wireless communication circuit between the transmitter circuit and the receiver circuit providing feedback control.
28. The WPT method according to claim 27 , wherein the receiver-side output power control is implemented using a voltage of the intermediate capacitor as an indicator for power flow control, and
wherein the decoupling switch is used as a control mechanism to regulate the voltage of the intermediate capacitor at a nominal value within a tolerance.
29. The WPT method according to claim 27 , wherein the receiver-side output power control is implemented using an output current to a load of the receiver circuit, and
wherein the decoupling switch is used as a control mechanism to regulate the output current to the load of the receiver circuit at a nominal value within a tolerance.
30. The WPT method according to claim 27 , wherein implementing transmitter-side input power control comprises detecting charging times and discharging times of the intermediate capacitor of the receiver circuit by detecting at least one electric variable in the transmitter circuit.
31. The WPT method according to claim 29 , wherein the detected charging times and discharging times are used to derive a control signal for closed-loop control on the transmitter side to control the input power.
32. The WPT method according to claim 31 , wherein the input power is controlled to dynamically meet the output power or load demand on the receiver side.
33. The WPT method according to claim 30 , wherein the at least one electric variable in the transmitter circuit comprises the magnitude of a current of the transmitter winding, the magnitude of a voltage of the transmitter winding, or both.
34. The WPT method according to claim 27 , wherein implementing receiver-side output power control comprises using hysteresis control to regulate the voltage of the intermediate capacitor to a nominal value within a tolerance or a hysteresis band.
35. The WPT method according to claim 27 , wherein the decoupling switch of the receiver circuit periodically decouples or isolates a load from receiving power directly from the receiver winding.
36. The WPT method according to claim 27 , wherein a load connected to the receiver circuit receives power stored in the intermediate capacitor when the decoupling switch of the receiver circuit is activated, thereby discharging the intermediate capacitor when the load receives the power stored in the intermediate capacitor.
37. The WPT method according to claim 27 , wherein the decoupling switch of the receiver circuit is a shunt decoupling switch or is a series decoupling switch.
38. The WPT method according to claim 27 , wherein implementing transmitter-side input power control comprises using a control variable to control the input power to the transmitter circuit.
39. The WPT method according to claim 38 , wherein the control variable comprises at least one of a phase-shift angle of an output voltage, a frequency of the output voltage, the magnitude of the output voltage, the magnitude of an output current, and a DC link voltage.
40. The WPT method according to claim 27 , wherein the transmitter-side input power control and the receiver-side output power control are implemented in analog form, digital form, or a combination thereof.
41. The WPT method according to claim 27 , wherein the transmitter winding is a transmitter coil and/or the receiver winding is a receiver coil.