BUFFERING ENERGY STORAGE SYSTEMS FOR REDUCED GRID AND VEHICLE BATTERY STRESS FOR IN-MOTION WIRELESS POWER TRANSFER SYSTEMS

• US 20160001662A1
• Filed: 02/25/2013
• Published: 01/07/2016
• Est. Priority Date: 02/25/2013
• Status: Abandoned Application

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: MILLER, John M., ONAR, Omer C.
• Application Number:
  US14/768,340
• Publication Number:
  US 20160001662A1
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 50/40 using propulsion power supplied by capacitors
• 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 53/36 by positioning the vehicle
• 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: 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 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• 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

An energy buffer including an electrochemical capacitor can be added to the primary circuit and/or to the secondary circuit of in-motion wireless power transfer system. The energy buffer(s) can smoothen the power delivered by the power grid and captured by a vehicle passing over an array of transmit coils through in-motion wireless power transfer. The reduction in the transient power transfer can reduce the peak current that flows through various components of the in-motion wireless power transfer system including a vehicle battery on the vehicle, and prolong the life of the in-motion wireless power transfer system.

Claims

1. A receiver circuit for wireless power transfer comprising:

a receiver coil and a receiver capacitor connected to said receiver coil;

a rectifier circuit configured to receive a voltage across said receiver capacitor as an input and to generate an output voltage including a direct current component and an alternating current (AC) ripple component;

an electrochemical capacitor directly or indirectly connected to said output voltage; and

a vehicle battery directly or indirectly connected to said output voltage.

2. The receiver circuit of claim 1, further comprising a bidirectional DC-DC converter connected between nodes of said output voltage of said rectifier circuit and nodes of said electrochemical capacitor.

3. The receiver circuit of claim 2, wherein a combination of said bidirectional DC-DC converter and said electrochemical capacitor is in parallel connection with said vehicle battery with respect to an output of said rectifier circuit.

4. The receiver circuit of claim 3, wherein said bidirectional DC-DC converter is a bidirectional buck-boost converter.

5. The receiver circuit of claim 2, further comprising a DC-DC converter connected between nodes of said output voltage of said rectifier circuit and nodes of said vehicle battery.

6. The receiver circuit of claim 1, further comprising a cascaded DC-DC converter having input nodes that are directly connected across said electrochemical capacitor and output nodes that are directly connected across nodes of said vehicle battery, wherein said electrochemical capacitor is connected directly to said output voltage.

7. The receiver circuit of claim 1, further comprising:

a first cascaded DC-DC converter having input nodes that are directly connected across output nodes of said rectifier circuit and output nodes that are directly connected across nodes of said electrochemical capacitor; and

a second cascaded DC-DC converter having input nodes that are directly connected across said electrochemical capacitor and output nodes that are directly connected across nodes of said vehicle battery.

8. A method of operating a receiver circuit for wireless power transfer in an electric vehicle, said method comprising:

providing a vehicle equipped with a receiver circuit of claim 1;

causing said vehicle to pass over a track of transmit pads including transmit coils and storing energy received from said transmit coils through wireless power transfer in said electrochemical capacitor; and

transferring energy stored in said electrochemical capacitor into said vehicle battery after said vehicle exits a region overlying said track of transmit pads.

9. The method of claim 8, wherein said receiver circuit further comprises a bidirectional DC-DC converter connected between nodes of said output voltage of said rectifier circuit and nodes of said electrochemical capacitor, and said method further comprises:

transferring energy from said rectifier circuit through said bidirectional DC-DC converter into said electrochemical capacitor while said vehicle passes over said track of transmit pads; and

transferring energy from said electrochemical capacitor through said bidirectional DC-DC converter into said vehicle battery after said vehicle exits said region overlying said track of transmit pads.

10. The method of claim 8, wherein said receiver circuit further comprises a cascaded DC-DC converter having input nodes that are directly connected across said electrochemical capacitor and output nodes that are directly connected across nodes of said vehicle battery, and said electrochemical capacitor is connected directly to said output voltage, and said method further comprises:

storing energy from said wireless power transfer into said electrochemical capacitor while said vehicle passes over said track of transmit pads; and

transferring energy from said electrochemical capacitor through said cascaded DC-DC converter into said vehicle battery after said vehicle exits said region overlying said track of transmit pads.

20. The method of claim 8, wherein said transmitter circuit further comprises a DC-DC converter including input nodes that are connected directly across said electrochemical capacitor, and including output nodes that are connected directly to said high frequency inverter, and wherein said energy stored in said electrochemical capacitor is transferred into said high frequency inverter though said DC-DC converter.

11. A transmitter circuit for wireless power transfer comprising:

an active front end (AFE) unit including input nodes configured to be connected to alternating current (AC) power from a power grid and output nodes configured to provide a unipolar output voltage;

a high frequency inverter configured to convert said unipolar output voltage or a direct current (DC) voltage derived from said unipolar output voltage into an AC output voltage in a frequency range from 1 kHz to 1 MHz;

at least one set of a primary coil and a primary capacitor connected to said high frequency inverter; and

an electrochemical capacitor connected to nodes between said power grid and said high frequency inverter.

12. The transmitter circuit of claim 11, further comprising a bidirectional rectifier/inverter including first nodes connected directly to said input nodes of said AFE unit and second nodes connected directly across nodes of said electrochemical capacitor.

13. The transmitter circuit of claim 12, wherein said bidirectional rectifier/inverter is configured to operate as a rectifier employing said first nodes as input nodes and employing said first nodes as output nodes while said at least one set is not loaded with electrical current.

14. The transmitter circuit of claim 12, wherein said bidirectional rectifier/inverter is configured to operate as an inverter employing said second nodes as input nodes and employing said first nodes as output nodes while said at least one set is loaded with electrical current.

15. The transmitter circuit of claim 11, further comprising a bidirectional DC-DC converter including first nodes connected directly to nodes providing said unipolar output voltage and including second nodes connected directly across nodes of said electrochemical capacitor.

16. The transmitter circuit of claim 11, wherein said electrochemical capacitor is connected directly across nodes providing said unipolar output voltage.

17. The transmitter circuit of claim 11, further comprising a DC-DC converter including input nodes that are connected directly across nodes providing said unipolar output voltage and directly across said electrochemical capacitor, and including output nodes that are connected directly to said high frequency inverter.

18. A method of operating a transmitter circuit for wireless power transfer, said method comprising:

providing a transmitter circuit of claim 11, wherein said at least one primary coil is located within a track of at least one transmit pad;

storing energy in said electrochemical capacitor while said at least one primary coil does not perform wireless power transfer; and

transferring energy stored in said electrochemical capacitor into said high frequency inverter while wireless power transfer is performed from said at least one primary coil to an electric vehicle passing over said track of at least one transmit pad.

19. The method of claim 18, wherein said transmitter circuit further comprises a bidirectional rectifier/inverter including first nodes connected directly to said input nodes of said AFE unit and second nodes connected directly across nodes of said electrochemical capacitor, and said method further comprises:

operating said bidirectional rectifier/inverter as a rectifier employing said first nodes as input nodes and employing said first nodes as output nodes while said at least one primary coil does not perform wireless power transfer; and

operating said bidirectional rectifier/inverter as an inverter employing said second nodes as input nodes and employing said first nodes as output nodes while said at least one primary coil performs wireless power transfer.