Series/series resonant topology for wireless power transfer

Patent metadata

Field	Value
Publication number	US-12003114-B2
Application number	US-202016913066-A
Country	US
Kind code	B2
Filing date	Jun 26, 2020
Priority date	Jun 26, 2020
Publication date	Jun 4, 2024
Grant date	Jun 4, 2024

Abstract

Aspects of an efficient compensation network for reducing reactive power in a wireless power transfer (WPT) system are disclosed. The compensation network comprises a series/series (S/S) constant current (CC) source, a reactive power compensation capacitor, and a constant current (CC)-to-constant voltage (CV) network. In an example, the S/S CC source comprises a first capacitor connected in series with a first inductor on a primary side of a transformer and a second inductor on a secondary side of the transformer. The S/S CC source converts an input voltage signal of the WPT system into a constant alternating current (AC) current signal. In an example, the CC-to-CV network comprises at least a third capacitor and a third inductor. The CC-to-CV network converts the constant AC current signal into a constant AC voltage signal.

First claim

Therefore, the following is claimed:

1. A wireless power transfer (WPT) system comprising:
a compensation network for reducing reactive power in the WPT system, the compensation network comprising:
a series/series (S/S) constant current (CC) source comprising a transformer and a S/S compensation network for the transformer, the S/S compensation network consisting of a first compensation capacitor and a second compensation capacitor, the first compensation capacitor being connected in series with a first inductor on a primary side of the transformer and the second compensation capacitor being connected in series with a second inductor on a secondary side of the transformer, the first compensation capacitor, the first inductor and a mutual inductance of the transformer configured for resonant operation at a defined frequency, the S/S CC source converting an input voltage signal of the WPT system into a constant alternating current (AC) current signal at the defined frequency; and
a constant current (CC)-to-constant voltage (CV) network comprising at least a third capacitor and a third inductor, the CC-to-CV network configured for resonant operation at the defined frequency, the CC-to-CV network converting the constant AC current signal into a constant AC voltage signal at the defined frequency.

2. The WPT system of claim 1 , further comprising:
a full-bridge inverter, wherein the defined frequency is a switching frequency of the full-bridge inverter, and:
the second compensation capacitor is electrically coupled between the second inductor and the third inductor; and
a value of the second compensation capacitor is selected for resonance with a self-inductance of the transformer under the switching frequency of the full-bridge inverter to allow the S/S CC source to operate as a CC source.

3. The WPT system of claim 2 , further comprising:
a full-bridge inverter, wherein:
the second compensation capacitor is electrically coupled to the third capacitor; and
a value of the second compensation capacitor is selected to provide inductive current in the full-bridge inverter for zero voltage switching (ZVS) of switches in the full-bridge inverter.

4. The WPT system of claim 1 , wherein the WPT system is a direct current (DC)-to-DC converter comprising a full-bridge inverter that converts the input voltage signal into AC energy.

5. The WPT system of claim 4 , wherein the DC-to-DC converter further comprises a diode-bridge rectifier that converts the constant AC voltage signal into a DC voltage signal.

6. The WPT system of claim 1 , wherein the WPT system is a direct current (DC)-to-AC converter comprising a full-bridge inverter that converts the input voltage signal into AC energy.

7. The WPT system of claim 1 , wherein the WPT system is an AC-to-direct current (DC) converter comprising a diode-bridge rectifier that converts the constant AC voltage signal into a DC voltage signal.

8. The WPT system of claim 1 , wherein the WPT system is an AC-to-AC converter.

9. The WPT system of claim 1 , further comprising:
a reactive power compensation capacitor electrically coupled to the third inductor and to an output node of the compensation network.

10. The WPT system of claim 9 , wherein the WPT system is a direct current (DC)-to-DC converter comprising a full-bridge inverter that converts the input voltage signal into AC energy.

11. The WPT system of claim 10 , wherein:
the DC-to-DC converter further comprises a diode-bridge rectifier that converts the constant AC voltage signal into a DC voltage signal; and
the reactive power compensation capacitor is coupled between inputs of the diode-bridge rectifier.

12. The WPT system of claim 9 , wherein the WPT system is a direct current (DC)-to-AC converter comprising a full-bridge inverter that converts the input voltage signal into AC energy.

13. The WPT system of claim 9 , wherein the WPT system is an AC-to-direct current (DC) converter comprising a diode-bridge rectifier that converts the constant AC voltage signal into a DC voltage signal.

14. The WPT system of claim 9 , wherein the WPT system is an AC-to-AC converter.

15. A method for reducing reactive power in a wireless power transfer (WPT) system, the method comprising:
providing a compensation network comprising:
a series/series (S/S) constant current (CC) source comprising a transformer and a S/S compensation network for the transformer, the S/S compensation network consisting of a first compensation capacitor and a second compensation capacitor, the first compensation capacitor being connected in series with a first inductor on a primary side of the transformer and the second compensation capacitor being connected in series with a second inductor on a secondary side of the transformer, the first compensation capacitor, the first inductor and a mutual inductance of the transformer configured for resonant operation at a defined frequency; and
a constant current (CC)-to-constant voltage (CV) network comprising at least a third capacitor and a third inductor, the CC-to-CV network configured for resonant operation at the defined frequency;

with the S/S CC source, converting an input voltage signal of the WPT system into a constant alternating current (AC) current signal at the defined frequency; and
with the CC-to-CV network, converting the constant AC current signal into a constant AC voltage signal at the defined frequency.

16. The method of claim 15 , further comprising:
prior to the S/S CC source converting the input voltage signal of the WPT system into the constant AC current signal, with a full-bridge inverter, converting the input voltage signal into AC energy, and wherein the S/S CC source converts the AC energy into the constant AC current signal.

17. The method of claim 16 , further comprising:
after the CC-to-CV network converts the constant AC current signal into the constant AC voltage signal, with a diode-bridge rectifier, converting the constant AC voltage signal into a DC voltage signal.

18. The method of claim 17 , further comprising:
filtering the DC voltage signal and applying the filtered DC voltage signal to a load of the WPT system.

19. The method of claim 16 , further comprising:
after the CC-to-CV network converts the constant AC current signal into the constant AC voltage signal, applying the constant AC voltage signal to a load of the WPT system.

20. The method of claim 15 , further comprising:
after the CC-to-CV network converts the constant AC current signal into the constant AC voltage signal, with a diode-bridge rectifier, converting the constant AC voltage signal into a DC voltage signal.

Assignees

• Virginia Tech Intellectual Properties Inc

Inventors

• Sun Keyao
• Wang Jun
• Burgos Rolando
• Boroyevich Dushan

Classifications

• H02J50/12 Primary

  of the resonant type · CPC title

• H02M7/5387

  in a bridge configuration · CPC title

• H02M1/0058 Primary

  by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero (using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826) · CPC title

• H02M1/4266

  using passive elements · CPC title

• H02M5/06

  using impedances · CPC title