Double-sided LCC compensation method for wireless power transfer

• US 9,789,777 B2
• Filed: 07/10/2014
• Issued: 10/17/2017
• Est. Priority Date: 07/11/2013
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Mi, Chris, Deng, Junjun, Nguyen, Trong-Duy, Li, Weihan, Li, Siqi
• Primary Examiner(s): Rodas, Richard Isla
• Assistant Examiner(s): Ruiz, Johali Torres
• Application Number:
  US14/328,077
• Publication Number:
  US 20150015197A1
• Time in Patent Office: 1,195 Days
• Field of Search: 320108
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/527 Voltage
• CPC Class Codes: B60L 2240/529 Current
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• CPC Class Codes: B60L 3/0023 Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 53/12 Inductive energy transfer
• 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 53/22 Constructional details or arrangements of charging converters specially adapted for charging electric vehicles
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H04B 5/26 using coils
• 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 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

Abstract

A double-sided LCC compensation network and a tuning method are proposed for a wireless power transfer system. With the proposed topology, the resonant frequency is independent of coupling coefficient and load conditions. The parameter values are tuned to realize zero voltage switching (ZVS) for the sending side switches. A wireless charging system with up to 7.7 kW output power was designed and built using the proposed topology and achieved 96% efficiency from DC power source to battery load.

Claims

1. A wireless power transfer system, comprising:

a send unit configured to transfer power using inductive power transfer, wherein the send unit includes;

an inverter configured to receive a DC input signal and convert the DC input signal to an AC output signal at a desired resonant frequency, wherein the inverter is further defined as a full bridge converter circuit comprised of four switches;

a send coil configured to receive the AC output signal from the inverter and generate an alternating electromagnetic field; and

a send side compensation circuit interconnecting the inverter with the send coil, wherein the compensation circuit is comprised of a send side inductor and a send side series capacitor serially coupled together at a node and to a positive terminal of the send coil, and a send side parallel capacitor coupled at the node and in parallel with the send coil;

a receive unit configured to receive power via inductive power transfer from the send coil of the send unit, wherein the receive unit includes

a receive coil configured to receive the alternating electromagnetic field from the send coil of the send unit and output an AC charging signal;

a receive side converter configured to receive the AC charging signal from the receive coil and convert the AC charging signal to a DC charging signal; and

a receive side compensation circuit interconnecting the receive coil with the receive side converter, wherein the receive side compensation circuit is comprised of a receive side inductor and a receive side series capacitor serially coupled together at a node and to a positive terminal of the receive coil, and a receive side parallel capacitor coupled at the node and in parallel with the receive coil; and

a controller electrically coupled to the four switches of the inverter and operates to turn all of the four switches on and off at a zero voltage switching condition, wherein the turn off current delivered by the controller is computed in accordance with

2. The wireless power transfer system of claim 1 wherein the switches are further defined as power metal-oxide-semiconductor field effect transistors (MOSFETs).

3. The wireless power transfer system of claim 1 wherein an equivalent receive side inductance for the received side series capacitor and the receive side inductor has a value larger than equivalent send side inductance for the send side series capacitor and the send side inductor.

4. The wireless power transfer system of claim 1 wherein Δ

L₂ is computed in accordance with

5. The wireless power transfer system of claim 1 wherein the receive side converter is further defined as a full wave rectifier circuit.

6. The wireless power transfer system of claim 5 further comprises a battery configured to receive the DC charging signal from the receive side converter.

7. The wireless power transfer system of claim 6 wherein the receive unit is integrated into a vehicle.

8. The wireless power transfer system of claim 1 wherein the send side inductor and the send coil share a ferrite coil and the receive side inductor and the receive coil share a ferrite coil.

9. A wireless power transfer system, comprising:

a send unit configured to transfer power using inductive power transfer, wherein the send unit includes;

a full bridge inverter circuit having four switches, the full bridge inverter circuit configured to receive the DC input signal and convert the DC input signal to an AC output signal at a desired resonant frequency;

a controller electrically coupled to each of the four switches and drives all of the switches on and off at a zero voltage switching condition;

a send coil configured to receive the AC output signal from the inverter circuit and generate an alternating electromagnetic field; and

a send side compensation circuit interconnecting the inverter circuit with the send coil, wherein the compensation circuit is comprised of a send side inductor and a send side series capacitor serially coupled together at a node and to a positive terminal of the send coil, and a send side parallel capacitor coupled at the node and in parallel with the send coil;

a receive unit configured to receive power via inductive power transfer from the send coil of the charging unit, wherein the receive unit includes

a receive coil configured to receive the alternating electromagnetic field from the send coil of the send unit and output an AC charging signal;

a receive side converter configured to receive the AC charging signal from the receive coil and convert the AC charging signal to a DC charging signal; and

a receive side compensation circuit interconnecting the receive coil with the receive side converter, wherein the receive side compensation circuit is comprised of a receive side inductor and a receive side series capacitor serially coupled together at a node and to a positive terminal of the receive coil, and a receive side parallel capacitor coupled at the node and in parallel with the receive coil;

wherein the turn off current delivered by the controller is computed in accordance with

10. The wireless power transfer system of claim 9 wherein an equivalent receive side inductance for the received side series capacitor and the receive side inductor has a value larger than equivalent send side inductance for the send side series capacitor and the send side inductor.

11. The wireless power transfer system of claim 9 wherein Δ

L_e2 is computed in accordance with

12. The wireless power transfer system of claim 9 wherein the receive side converter is further defined as a full wave rectifier circuit.

13. The wireless power transfer system of claim 12 further comprises a battery configured to receive the DC charging signal from the receive side converter.

14. The wireless power transfer system of claim 13 wherein the receive unit is integrated into a vehicle.

15. The wireless power transfer system of claim 9 wherein the send side inductor and the send coil share a ferrite coil and the receive side inductor and the receive coil share a ferrite coil.