Load control for bi-directional inductive power transfer systems

• US 9,660,702 B2
• Filed: 06/27/2012
• Issued: 05/23/2017
• Est. Priority Date: 06/27/2011
• Status: Active Grant

• Current Assignee: Auckland UniServices Limited (Auckland University)
• Original Assignee: Auckland UniServices Limited (Auckland University)
• Inventors: Thrimawithana, Duleepa Jayanath, Madawala, Udaya Kumara
• Primary Examiner(s): Johnson, Ryan
• Application Number:
  US14/127,882
• Publication Number:
  US 20140203659A1
• Time in Patent Office: 1,791 Days
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• 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 53/63 in response to network capacity
• CPC Class Codes: B60L 53/65 involving identification of vehicles or their battery types
• CPC Class Codes: B60L 55/00 Arrangements for supplying energy stored within a vehicle to a power network, i.e. vehicle-to-grid [V2G] arrangements
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02M 1/008 Plural converter units for generating at two or more independent and non-parallel outputs, e.g. systems with plural point of load switching regulators
• CPC Class Codes: H02M 7/4815 Resonant converters H02M7/4811 and H02M7/4826 take precedence
• CPC Class Codes: H02M 7/797 using semiconductor devices only
• 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: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• 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 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles
• CPC Class Codes: Y02T 90/167 : Systems integrating technologies related to power network operation and communication or information technologies for supporting the interoperability of electric or hybrid vehicles, i.e. smartgrids as interface for battery charging of electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: Y04S 10/126 : the energy generation units being or involving electric vehicles [EV] or hybrid vehicles [HEV], i.e. power aggregation of EV or HEV, vehicle to grid arrangements [V2G]
• CPC Class Codes: Y04S 30/14 : Details associated with the interoperability, e.g. vehicle recognition, authentication, identification or billing

Abstract

A control method for use in a primary side power converter (1) of an inductive power transfer (IPT) system. The power transfer from the primary side to one or more secondary pick-ups is monitored, and the operating frequency of the primary side power converter (1) is varied in proportion to a difference between the monitored power transfer and a power capability of the primary side power converter. The frequency variation can be sensed by the or each pick-up (2) to regulate the power transfer and to prevent overloading from occurring.

Claims

1. A control method for use in a primary side power converter of an inductive power transfer (IPT) system, the method comprising the steps of:

sensing power transfer between the primary side power converter and one or more IPT pick-ups with which the primary side power converter is capable of being inductively coupled, in use; and

varying the operating frequency of the primary side power converter in proportion to a difference between said power transfer and a power capability of the primary side power converter, whereby said variation is capable of being sensed by each of the one or more pick-ups to regulate said power transfer.

2. The method according to claim 1 wherein the step for varying the operating frequency comprises varying the operating frequency in incremental steps.

3. The method according to claim 1 wherein the step of varying the operating frequency comprises periodically varying the operating frequency.

4. The method according to claim 3 wherein the step of varying the operating frequency comprises maintaining the operating frequency for a portion of each period, and reverting to the tuned frequency for the remainder of each period.

5. The method according to claim 1 wherein the tuned frequency is a frequency to which resonant circuits of both the primary and secondary sides are tuned.

6. The method according to claim 1 wherein the method includes continuously monitoring the power transfer.

7. The method according to claim 1 wherein the method includes the step of periodically monitoring the power transfer.

8. The method according to claim 1 including the step of varying the operating frequency within a predetermined range of the tuned frequency.

17. The method according to claim 2 wherein the step of varying the operating frequency comprises periodically varying the operating frequency.

18. The method according to claim 17 wherein the step of varying the operating frequency comprises maintaining the operating frequency for a portion of each period, and reverting to the tuned frequency for the remainder of each period.

9. An inductive power transfer primary side power converter, the converter including a sensor to sense power transfer between the primary side power converter and one or more IPT pick-ups with which the primary side power converter is capable of being inductively coupled in use;

and

a controller for varying the operating frequency of the primary side power converter with respect to a tuned frequency in proportion to a difference between said power transfer and a power capability of the primary side power converter, whereby said variation is capable of being sensed by each of the one or more pick-ups each pick-ups to regulate said power transfer.

10. The inductive power transfer primary side power converter according to claim 9 wherein the operating frequency is varied in incremental steps.

11. The inductive power transfer primary side power converter according to claim 9 wherein the controller periodically varies the operating frequency.

12. The inductive power transfer primary side power converter according to claim 11 wherein the controller maintains the operating frequency for a portion of each period, and reverts to the tuned frequency for the remainder of each period.

13. The inductive power transfer primary side power converter according to claim 9 wherein the tuned frequency is a frequency to which resonant circuits of both the primary and secondary sides are tuned.

14. The inductive power transfer primary side power converter according to claim 9 wherein the controller continuously monitors the power transfer.

15. The inductive power transfer primary side power converter according to claim 9 wherein the controller periodically monitors the power transfer.

16. The inductive power transfer primary side power converter according to claim 9 wherein the controller varies the operating frequency within a predetermined range of the tuned frequency.

19. The inductive power transfer primary side power converter according to claim 10 wherein the controller periodically varies the operating frequency.

20. The inductive power transfer primary side power converter according to claim 19 wherein the controller maintains the operating frequency for a portion of each period, and reverts to the tuned frequency for the remainder of each period.