Wireless power transfer system

• US 9,269,489 B2
• Filed: 01/23/2013
• Issued: 02/23/2016
• Est. Priority Date: 01/23/2012
• Status: Expired due to Fees

• Current Assignee: Utah State University
• Original Assignee: Utah State University
• Inventors: Wu, Hunter, Sealy, Kylee, Gilchrist, Aaron
• Primary Examiner(s): Ngo, Brian
• Application Number:
  US13/748,269
• Publication Number:
  US 20130207601A1
• Time in Patent Office: 1,126 Days
• Field of Search: 320/108, 320/109
• US Class Current: 1/1
• 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: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02M 7/53871 with automatic control of output voltage or current
• 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

A system includes a first stage of an inductive power transfer system with an LCL load resonant converter with a switching section, an LCL tuning circuit, and a primary receiver pad. The IPT system includes a second stage with a secondary receiver pad, a secondary resonant circuit, a secondary rectification circuit, and a secondary decoupling converter. The secondary receiver pad connects to the secondary resonant circuit. The secondary resonant circuit connects to the secondary rectification circuit. The secondary rectification circuit connects to the secondary decoupling converter. The second stage connects to a load. The load includes an energy storage element. The second stage and load are located on a vehicle and the first stage is located at a fixed location. The primary receiver pad wirelessly transfers power to the secondary receiver pad across a gap when the vehicle positions the secondary receiver pad with respect to the primary receiver pad.

Claims

1. A system comprising:

a first stage of an inductive power transfer (“

IPT”

) system, the first stage comprising an inductor-capacitor-inductor (“

LCL”

) load resonant converter with a switching section, an LCL tuning circuit, a primary receiver pad, and a primary controller, wherein the switching section connects a direct current (“

DC”

) voltage to the LCL tuning circuit, the switching section connecting the DC voltage in a positive polarity and in a negative polarity during a switching cycle of the switching section, and wherein the primary receiver pad is connected as a load to the LCL tuning circuit, and wherein the primary controller controls switching in the switching section;

a second stage of the IPT system, the second stage comprising a secondary receiver pad, a secondary resonant circuit, a secondary rectification circuit, a secondary decoupling converter, and a secondary decoupling controller, wherein the secondary receiver pad connects to the secondary resonant circuit, the secondary resonant circuit connects to the secondary rectification circuit, the secondary rectification circuit connects to the secondary decoupling converter, and wherein the secondary decoupling controller controls switching in the secondary decoupling converter; and

a load connected to the IPT system, the load connected to an output of the second stage, the load comprising at least an energy storage element, wherein the second stage and load are located on a vehicle and the first stage is located at a fixed location, and wherein the primary receiver pad wirelessly transfers power to the secondary receiver pad across a gap when the vehicle positions the secondary receiver pad with respect to the primary receiver pad.

2. The apparatus of claim 1, wherein the switching section of the first stage comprises an H-bridge switching converter.

3. The apparatus of claim 2, wherein the H-bridge switching converter comprises insulated gate bipolar transistors (“

IGBT”

).

4. The apparatus of claim 1, wherein the primary controller controls conduction angle (“

σ

”

) of the switching section.

5. The apparatus of claim 4, wherein the primary controller controls the switching section using one or more of symmetric voltage-cancellation (“

SVC”

) control, asymmetric voltage-cancellation (“

AVC”

) control, and asymmetric duty cycle (“

ADC”

) control.

6. The apparatus of claim 5, further comprising a dual side control algorithm that maximizes efficiency of the IPT system, the dual side control algorithm adjusting a reference that controls conduction angle of the first stage and a reference that controls duty cycle of the second stage to maximize the efficiency.

7. The apparatus of claim 1, further comprising a first wireless communication module in the first stage and a second wireless communication module in the second stage, the first wireless communication module and the second wireless communication module communicating wirelessly when the vehicle is within a wireless range of the first stage.

8. The apparatus of claim 1, further comprising a rectifier section in the first stage, the rectifier section connecting to an alternating current (“

AC”

) power source and to the switching section of the first stage, the rectifier section rectifying an AC voltage from the AC power source, the rectifier section comprising the DC voltage for the switching section of the first stage.

9. The apparatus of claim 8, wherein the rectifier section comprises an active power factor correction switching power converter that corrects a power factor and harmonics of current drawn by the switching section of the first stage.

10. The apparatus of claim 1, wherein the energy storage element comprises a battery located on the vehicle, the battery providing power to an electric drive system of the vehicle, and wherein the secondary decoupling converter of the second section provides power to one or more of

charge the battery;

and

provide power to the electric drive system.

11. The apparatus of claim 1, further comprising two or more first power stages, each first power stage located at a location where the vehicle stops, the first power stage wirelessly transferring power to the second stage while the secondary receiver pad is aligned with the primary receiver pad of the first stage where the vehicle is located.

12. The apparatus of claim 1, further comprising one or more alignment sensors, the alignment sensors positioned with respect to the primary receiver pad and the secondary receiver pad to indicate when the secondary receiver pad is aligned with the primary receiver pad.

13. The apparatus of claim 1, wherein the primary receiver pad and the secondary receiver pad comprise:

a substantially planar surface that faces the primary receiver pad or the secondary receiver pad;

a plurality of linear magnetic elements positioned to extend radially from a center of the primary receiver pad or the secondary receiver pad and positioned substantially parallel to the planar surface; and

a conductor wound in a circular pattern in the plurality of linear magnetic elements to be substantially parallel with the substantially planar surface, the conductor wound with a plurality of layers, each layer positioned next to an adjacent layer, each layer extending radially from the center of the pad in a direction perpendicular to the substantially planar surface, each conductor comprising a plurality of smaller conductors.

14. The apparatus of claim 1, wherein the second stage delivers power to the load in a range of 5 kilowatts (“

kW”

) to 200 kW with an efficiency of the IPT system of over 90 percent.

15. The apparatus of claim 1, wherein the secondary decoupling converter of the second stage is a boost converter, the boost converter boosting an input voltage from the secondary resonant circuit to a higher output voltage of the load.

16. The apparatus of claim 1, wherein the vehicle aligns the secondary receiver pad with respect to the primary receiver pad such that the secondary receiver pad is over the primary receiver pad and a center of the secondary receiver pad is substantially aligned with a center of the primary receiver pad, wherein substantially aligning the center of the secondary receiver pad with the center of the primary receiver pad comprises an amount of misalignment within a misalignment limit.

17. A system comprising:

a first stage of an inductive power transfer (“

IPT”

) system, the first stage comprising

a rectifier section;

an H-bridge switching section;

an inductor-capacitor-inductor (“

LCL”

) tuning circuit;

a primary receiver pad; and

a primary controller,

wherein the rectifier section rectifies an alternating current (“

AC”

) voltage and provides a direct current (“

DC”

) voltage to the H-bridge switching section, wherein the H-bridge switching section connects the DC voltage to the LCL tuning circuit, the H-bridge switching section connecting the DC voltage in a positive polarity and in a negative polarity during a switching cycle of the H-bridge switching section, and wherein the primary receiver pad is connected as a load to the LCL tuning circuit, and wherein the primary controller controls switching in the H-bridge switching section;

a second stage of the IPT system, the second stage comprising

a secondary receiver pad;

a secondary resonant circuit;

a secondary rectification section;

a secondary boost converter; and

a secondary decoupling controller,

wherein the secondary receiver pad connects to the secondary resonant circuit and the secondary resonant circuit connects to the secondary rectification section, the secondary rectification section connects to the secondary boost converter, and wherein the secondary decoupling controller controls switching in the secondary boost converter; and

a load connected to the IPT system, the load connected to an output of the second stage, the load comprising a battery and an electric drive system of a vehicle, wherein the second stage and load are located on the vehicle and the first stage is located at a fixed location, and wherein the primary receiver pad wirelessly transfers power to the secondary receiver pad when the vehicle positions the secondary receiver pad with respect to the primary receiver pad, the secondary boost converter providing power for one or more of charging the battery and powering the electric drive system of the vehicle.

18. A method comprising:

connecting and disconnecting, through a switching section of a first stage of an inductive power transfer (“

IPT”

) system, a direct current (“

DC”

) voltage to an inductor-capacitor-inductor (“

LCL”

) tuning circuit of the first stage, the LCL tuning circuit connected to a primary receiver pad of the first stage, connecting of the DC voltage comprising connecting in both a positive polarity and a negative polarity during a switching cycle of the switching section;

wirelessly transferring power from the primary receiver pad of the first stage across a gap to a secondary receiver pad in a second stage of the IPT system when the secondary receiver pad is aligned with respect to the primary receiver pad;

transferring power from the secondary receiver pad of the second stage to a secondary resonant circuit of the second stage;

rectifying, with a secondary rectification circuit of the second stage, power from the secondary resonant circuit of the second stage;

transferring power from the secondary rectification circuit of the second stage to a secondary decoupling converter of the second stage; and

transferring power from the secondary decoupling converter of the second stage to a load, wherein the second stage and load are located in a vehicle, the primary receiver pad wirelessly transmitting power to the secondary receiver pad when the vehicle positions the secondary receiver pad with respect to the primary receiver pad.

19. The method of claim 18, further comprising controlling, using a primary controller, a conduction angle of the switching section of the first stage and controlling, using a secondary decoupling controller, a duty cycle of the secondary decoupling converter of the second stage.

20. The method of claim 18, further comprising using a dual side control algorithm to maximize efficiency of the IPT system, the dual side control algorithm adjusting a reference used to control the conduction angle of the first stage and adjusting a reference used to control the duty cycle of the secondary decoupling converter of the second stage.

21. The method of claim 18, further comprising

sensing position of the secondary receiver pad with respect to the primary receiver pad;

communicating primary receiver pad and secondary receiver pad position information; and

using the primary receiver pad and secondary receiver pad position information to align the secondary receiver pad with respect to the primary receiver pad.