DUAL SIDE CONTROL FOR INDUCTIVE POWER TRANSFER

• US 20130207468A1
• Filed: 01/23/2013
• Published: 08/15/2013
• Est. Priority Date: 01/23/2012
• Status: Active Grant

• Current Assignee: Utah State University
• Original Assignee: Utah State University
• Inventors: Wu, Hunter, Sealy, Kylee, Gilchrist, Aaron
• Granted Patent: US 9,761,370 B2
• Time in Patent Office: Days
• US Class Current: 307/31
• 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

An apparatus for dual side control includes a measurement module that measures a voltage and a current of an IPT system. The voltage includes an output voltage and/or an input voltage and the current includes an output current and/or an input current. The output voltage and the output current are measured at an output of the IPT system and the input voltage and the input current measured at an input of the IPT system. The apparatus includes a max efficiency module that determines a maximum efficiency for the IPT system. The max efficiency module uses parameters of the IPT system to iterate to a maximum efficiency. The apparatus includes an adjustment module that adjusts one or more parameters in the IPT system consistent with the maximum efficiency calculated by the max efficiency module.

Claims

1. An apparatus comprising:

a measurement module that measures a voltage and a current of an inductive power transfer (“

IPT”

) system, the voltage comprising one or more of an output voltage and an input voltage, the current comprising one or more of an output current and an input current, the output voltage and the output current measured at an output of the IPT system, the input voltage and the input current measured at an input of the IPT system;

a max efficiency module that determines a maximum efficiency for the IPT system, the max efficiency module using parameters of the IPT system to iterate to a maximum efficiency; and

an adjustment module that adjusts one or more parameters in the IPT system consistent with the maximum efficiency calculated by the max efficiency module.

2. The apparatus of claim 1, wherein the IPT system includes a first stage and a second stage, wherein the first stage transmits energy wirelessly and the second stage receives the wirelessly transferred energy and controls energy transfer to one or more loads via an output bus, wherein the output voltage and the output current are measured on the output bus.

3. The apparatus of claim 2, wherein the first stage comprises an LCL load resonant converter and the second stage comprises one or more of a secondary resonant circuit, a secondary rectification circuit and a secondary decoupling circuit.

4. The apparatus of claim 3, wherein at least one load comprises an energy storage device.

5. The apparatus of claim 2, wherein the one or more parameters adjusted by the adjustment module comprise one or more of a duty cycle reference that adjusts a duty cycle of the second stage and a conduction angle reference that adjusts conduction angle of the first stage.

6. The apparatus of claim 5, wherein the adjustment module adjusting one or more of the duty cycle reference and the conduction angle reference comprise an outer control loop, wherein one or more of

the first stage comprises a first stage inner loop controlling conduction angle based on the conduction angle reference, the first stage inner loop controlling conduction angle faster than the outer loop control;

and

the second stage comprises a second stage inner loop controlling duty cycle based on the duty cycle reference, the second stage inner loop controlling duty cycle faster than the outer loop control.

7. The apparatus of claim 2, wherein the max efficiency module determines the maximum efficiency by iterating using one or more variables, the one or more variables comprising:

conduction angle of the first stage;

duty cycle of the second stage;

size of a gap, the IPT system transferring power wirelessly across the gap;

misalignment of a primary receiver pad and a secondary receiver pad, the IPT system transferring power wirelessly from the primary receiver pad to the secondary receiver pad;

power transferred to the one or more loads; and

a quality factor.

8. The apparatus of claim 2, wherein the max efficiency module determines the maximum efficiency by determining an efficiency of at least the first stage and the second stage for the measured voltage and current.

9. The apparatus of claim 8, wherein the max efficiency module determines the maximum efficiency where efficiency of the IPT system is calculated as:

η

=η

_r1·

η

_c1·

η

_r2·

η

_b2·

η

_c2, wherein

η

is IPT system efficiency;

η

_r1 is efficiency of the first stage without voltage drop;

η

_c1 is efficiency of first stage without linear resistance loss,

η

_r2 is efficiency of a secondary resonant circuit of the second stage;

η

_b2 is efficiency of a secondary rectification circuit and a secondary decoupling circuit of the second stage without voltage drop; and

η

_c2 is efficiency of the secondary rectification circuit and the secondary decoupling circuit of the second stage with linear resistance loss.

10. The apparatus of claim 9, wherein the first stage comprises an LCL load resonant converter and the secondary decoupling circuit comprises a secondary boost converter and wherein η

_r1 is calculated as;

11. The apparatus of claim 10, wherein the first stage comprises an LCL load resonant converter and the secondary decoupling circuit comprises a secondary boost converter and wherein Z_r is calculated as:

Z_r=Re(Z_r)+j*Im(Z_r)

where

12. The apparatus of claim 11, wherein M is calculated as:

13. The apparatus of claim 9, wherein the first stage comprises an LCL load resonant converter and the secondary decoupling circuit comprises a secondary boost converter and wherein η

_c1 is calculated as;

14. The apparatus of claim 9, wherein the first stage comprises an LCL load resonant converter and the secondary decoupling circuit comprises a secondary boost converter and wherein η

_r2 is calculated as;

15. The apparatus of claim 9, wherein the first stage comprises an LCL load resonant converter and the secondary decoupling circuit comprises a secondary boost converter and wherein η

_b2 is calculated as;

16. The apparatus of claim 9, wherein the first stage comprises an LCL load resonant converter and the secondary decoupling circuit comprises a secondary boost converter and wherein η

_c2 is calculated as;

17. A system comprising:

a first stage comprising a primary receiver pad;

a second stage comprising a secondary receiver pad;

an output power bus, wherein the first stage transmits energy wirelessly from the primary receiver pad and the second stage receives the wirelessly transferred energy in the secondary receiver pad, the second stage controlling energy transfer to one or more loads via the output bus, the first stage, the second stage, and the output power bus comprising at least a portion of an inductive power transfer (“

IPT”

) system;

a measurement module that measures a voltage and a current, the voltage and current measured on one or more of the output bus and an input to the IPT system;

a max efficiency module that determines a maximum efficiency for the IPT system, the max efficiency module using parameters of the IPT system to iterate to a maximum efficiency; and

an adjustment module that adjusts one or more parameters in the IPT system consistent with the maximum efficiency calculated by the max efficiency module.

18. The system of claim 17, further comprising an energy storage device, the energy storage device comprising a load of the one or more loads.

19. The system of claim 18, wherein the energy storage device provides power to a vehicle, the second stage and the energy storage device residing on the vehicle, the vehicle receiving power wirelessly from the first stage when the secondary receiver pad is at least partially aligned with the primary receiver pad.

20. The system of claim 17, wherein the first stage comprises a rectifier stage, the rectifier stage rectifying an alternating current (“

AC”

) voltage connected as input power to the first stage.

21. The system of claim 17, wherein the first stage comprises an LCL load resonant converter and the second stage comprises a secondary resonant circuit, a secondary rectification circuit, and a secondary boost converter and wherein the max efficiency module determines the maximum efficiency where efficiency of the IPT system is calculated as:

η

=η

_r1·

η

_c1·

η

_r2·

η

_b2·

η

_c2, wherein

η

is IPT system efficiency;

η

_r1 is efficiency of the first stage without voltage drop;

η

_c1 is efficiency of first stage without linear resistance loss,

η

_r2 is efficiency of a secondary resonant circuit of the second stage;

η

_b2 is efficiency of the secondary rectification circuit and the secondary boost converter of the second stage without voltage drop; and

η

_c2 is efficiency of the secondary rectification circuit and the secondary boost converter of the second stage with linear resistance loss.

22. A method comprising:

measuring a voltage and a current of an inductive power transfer (“

IPT”

) system, the voltage comprising one or more of an output voltage and an input voltage, the current comprising one or more of an output current and an input current, the output voltage and the output voltage measured at an output of the IPT system, the input voltage and the input current measured at an input of the IPT system;

determining a maximum efficiency for the IPT system using parameters of the IPT system to iterate to a maximum efficiency; and

adjusting one or more parameters in the IPT system consistent with the calculated maximum efficiency.

23. The method of claim 22, wherein the IPT system includes a first stage and a second stage, wherein the first stage transmits energy wirelessly and the second stage receives the wirelessly transferred energy and controls energy transfer to one or more loads via an output bus, wherein the first stage comprises an LCL load resonant converter and the second stage comprises one or more of a secondary resonant circuit, a secondary rectification circuit and a secondary decoupling circuit, and wherein at least one load comprises an energy storage device.

24. The method of claim 22, wherein adjusting the one or more parameters comprises adjusting one or more of a duty cycle reference that adjusts a duty cycle of the second stage and a conduction angle reference that adjusts conduction angle of the first stage and wherein adjusting one or more of the duty cycle reference and the conduction angle reference comprise an outer control loop, wherein one or more of:

the first stage comprises a first stage inner loop controlling conduction angle based on the conduction angle reference, the first stage inner loop controlling conduction angle faster than the outer loop control; and

the second stage comprises a second stage inner loop controlling duty cycle based on the duty cycle reference, the second stage inner loop controlling duty cycle faster than the outer loop control.

25. The method of claim 22, wherein determining the maximum efficiency comprises determining the maximum efficiency by iterating using one or more variables, the one or more variables comprising:

conduction angle of the first stage;

duty cycle of the second stage;

size of a gap, the IPT system transferring power wirelessly across the gap;

misalignment of a primary receiver pad and a secondary receiver pad, the IPT system transferring power wirelessly from the primary receiver pad to the secondary receiver pad;

power transferred to the one or more loads; and

a quality factor.