CONTROLLING WIRELESS POWER TRANSFER SYSTEMS

• US 20170217325A1
• Filed: 02/02/2017
• Published: 08/03/2017
• Est. Priority Date: 02/02/2016
• Status: Active Grant

• Current Assignee: WiTricity Corporation
• Original Assignee: WiTricity Corporation
• Inventors: DeBaun, David R., Kurs, Andre B.
• Granted Patent: US 10,263,473 B2
• Time in Patent Office: Days
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: B60L 53/126 Methods for pairing a vehicle and a charging station, e.g. establishing a one-to-one relation between a wireless power transmitter and a wireless power receiver
• CPC Class Codes: B60L 53/38 specially adapted for charging by inductive energy transfer
• CPC Class Codes: B60L 53/39 with position-responsive activation of primary coils
• CPC Class Codes: G05F 1/66 Regulating electric power
• CPC Class Codes: H02J 50/12 of the resonant type
• 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: H02M 3/24 by static converters
• CPC Class Codes: H03H 7/38 Impedance-matching networks
• CPC Class Codes: H03H 7/40 Automatic matching of load impedance to source impedance
• CPC Class Codes: H04B 5/24 Inductive coupling
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

Methods, systems, and devices for operating wireless power transfer systems. One aspect features a wireless energy transfer system that includes a transmitter, and a receiver. The transmitter has a transmitter-IMN and is configured to perform operations including performing a first comparison between a characteristic of a power of the transmitter and a target power. Adjusting, based on the first comparison, a reactance of the transmitter-IMN to adjust the power of the transmitter. The receiver has a receiver-IMN and is configured to perform operations including determining an efficiency of the wireless energy transfer system at a second time based on power data from the transmitter. Performing a second comparison between the efficiency at the second time and an efficiency of the wireless energy transfer system at a first time, the first time being prior to the second time. Adjusting, based on the second comparison, a reactance of the receiver-IMN.

Claims

1. A wireless energy transfer system comprising:

an energy transmitter comprising a transmitter-impedance matching network (IMN), the transmitter configured to perform operations comprising;

performing a first comparison between a characteristic of a power of the transmitter and a target power; and

adjusting, based on the first comparison, a reactance of the transmitter-IMN to adjust the power of the transmitter; and

an energy receiver comprising a receiver-IMN, the receiver configured to perform operations comprising;

determining an efficiency of the wireless energy transfer system at a second time based on power data from the transmitter;

performing a second comparison between the efficiency at the second time and an efficiency of the wireless energy transfer system at a first time, the first time being prior to the second time; and

adjusting, based on the second comparison, a reactance of the receiver-IMN.

2. The system of claim 1, wherein adjusting the reactance of the receiver-IMN comprises adjusting the reactance of the receiver-IMN by a variable reactance adjustment value.

3. The system of claim 1, wherein the first comparison and adjustment to the reactance of the transmitter-IMN occur iteratively until the characteristic of the power is within a threshold value of the target power.

4. The system of claim 1, wherein adjusting the reactance of the receiver-IMN comprises in response to the efficiency at the second time being less than the efficiency at the first time, negating a reactance adjustment value, and wherein adjusting the reactance of the receiver-IMN comprises adjusting the reactance of the receiver-IMN by the negated reactance adjustment value.

5. The system of claim 1, wherein adjusting the reactance of the transmitter-IMN comprises in response to the power being less than the target power, adjusting the reactance of the transmitter-IMN by a first reactance adjustment value and in response to the power being greater than the target power, adjusting the reactance of the transmitter-IMN by a second, different reactance adjustment value.

6. The system of claim 1, wherein the transmitter is an electric vehicle charger and wherein the receiver is a coupled to a power system of an electric vehicle.

7. The system of claim 1, wherein the first comparison is between a power factor of the power of the transmitter and a target power factor, and wherein the operations of the transmitter further comprise:

a third comparison between a magnitude of the power and a target power magnitude, wherein the third comparison follows the first comparison; and

adjusting, based on the third comparison, a bus voltage of the transmitter to adjust the power of the transmitter.

8. The system of claim 7, wherein the power factor is represented by a phase relationship between a transmitter voltage and a transmitter current.

9. The system of claim 7, wherein the first comparison and adjustment of the reactance of the transmitter-IMN based on the first comparison occur iteratively until the power factor of the power is within a threshold value of the target power factor.

10. The system of claim 7, wherein the steps of performing the first comparison and adjusting the reactance of the transmitter-IMN are iterated at a faster rate than the steps of performing the third comparison and adjusting the bus voltage.

11. The system of claim 1, wherein the operations of the transmitter further comprise shutting down the wireless energy transfer system by reducing the target power to zero.

12. The system of claim 1, wherein the operations of the transmitter further comprise starting up the transmitter by adjusting the reactance of the transmitter-IMN to a maximum value.

13. The system of claim 1, wherein the operations of the transmitter further comprise starting up the transmitter by adjusting a frequency of an inverter to a target frequency.

14. The system of claim 1, wherein the operations of the receiver further comprise starting up the receiver by adjusting the reactance of the receiver-IMN to a minimum value.

15. The system of claim 1, wherein the transmitter-IMN comprises a tunable reactive element electrically connected between an inverter and at least one fixed reactive element, and wherein adjusting the reactance of the transmitter-IMN comprises adjusting the tunable reactive element.

16. The system of claim 1, wherein the receiver-IMN comprises a tunable reactive element electrically connected between a rectifier and at least one fixed reactive element, and wherein adjusting the reactance of the receiver-IMN comprises adjusting the tunable reactive element.

17. The system of claim 1, wherein the steps of performing the first comparison and adjusting the reactance of the transmitter-IMN are iterated at a faster rate than the steps of performing the second comparison and adjusting the reactance of the receiver-IMN.

18. The system of claim 1, wherein determining the efficiency of the wireless energy transfer system comprises:

receiving power data from the transmitter;

determining an output power of the receiver; and

calculating the efficiency of the wireless energy transfer system based on the power data from the transmitter and the output power of the receiver.

19. A wireless energy transmitter comprising a transmitter-impedance matching network (IMN), the transmitter configured to perform operations comprising:

performing a first comparison between a characteristic of a power of the transmitter and a target power;

adjusting, based on the first comparison, a reactance of the transmitter-IMN to adjust the power of the transmitter; and

transmitting power data that indicates the power of the transmitter to a wireless energy receiver.

20. A wireless energy receiver comprising a receiver-impedance matching network (IMN), the receiver configured to perform operations comprising:

determining an efficiency of a wireless energy transfer system at a second time based on power data from a wireless energy transmitter;

performing a second comparison between the efficiency at the second time and an efficiency of the wireless energy transfer system at a first time, the first time being prior to the second time; and

adjusting, based on the second comparison, a reactance of the receiver-IMN.