Utilization of rotor kinetic energy storage for hybrid vehicles

• US 7,936,076 B2
• Filed: 01/22/2008
• Issued: 05/03/2011
• Est. Priority Date: 01/22/2007
• Status: Active Grant

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: Hsu, John S.
• Primary Examiner(s): Waks; Joseph
• Application Number:
  US12/009,682
• Publication Number:
  US 20080173486A1
• Time in Patent Office: 1,197 Days
• Field of Search: 290/1.A, 310/114
• US Class Current: 290/1.00A
• CPC Class Codes: B60K 6/105 the accumulator being a flywheel
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• CPC Class Codes: B60L 2210/30 AC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/12 Speed
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/30 using propulsion power stored mechanically, e.g. in fly-wheels
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 50/61 by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: H02K 51/00 Dynamo-electric gears, i.e. dynamo-electric means for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts
• CPC Class Codes: H02K 7/02 Additional mass for increasing inertia, e.g. flywheels
• CPC Class Codes: Y02E 60/16 Mechanical energy storage, e.g. flywheels or pressurised fluids
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• 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

Abstract

A power system for a motor vehicle having an internal combustion engine, the power system comprises an electric machine (12) further comprising a first excitation source (47), a permanent magnet rotor (28) and a magnetic coupling rotor (26) spaced from the permanent magnet rotor and at least one second excitation source (43), the magnetic coupling rotor (26) also including a flywheel having an inertial mass to store kinetic energy during an initial acceleration to an operating speed; and wherein the first excitation source is electrically connected to the second excitation source for power cycling such that the flywheel rotor (26) exerts torque on the permanent magnet rotor (28) to assist braking and acceleration of the permanent magnet rotor (28) and consequently, the vehicle. An axial gap machine and a radial gap machine are disclosed and methods of the invention are also disclosed.

Claims

1. A power system for a motor vehicle having an internal combustion engine, the power system comprising:

an electric machine comprising;

a first excitation source having coils for receiving ac electrical power to provide a magnetic field;

a permanent magnet rotor spaced from the stator to define a first air gap relative to the permanent magnet rotor;

a magnetic coupling rotor spaced from the permanent magnet rotor to define a second air gap relative to the permanent magnet rotor; and

at least one secondary excitation source spaced from the magnetic coupling rotor by a third air gap to provide slip-energy excitation to the magnetic coupling rotor; and

wherein the magnetic coupling rotor also includes a flywheel having an inertial mass to store kinetic energy during an initial acceleration of the permanent magnet rotor to an operating speed; and

wherein the first excitation source is electrically connected to the second excitation source for power cycling such that the flywheel rotor exerts torque on the permanent magnet rotor to assist braking and acceleration of the permanent magnet rotor.

2. The power system of claim 1, wherein power can be returned from the first excitation source to the second excitation source to accelerate the magnetic coupling rotor, and to speed up or slow down the permanent magnet rotor.

3. The power system of claim 1, wherein the second excitation source can used stored energy in the flywheel to operate as a generator to supply power to the permanent magnet rotor for acceleration.

4. The power system of claim 1, wherein the electric machine provides an axial air gap between the permanent magnet rotor and the slip-energy magnetic coupling rotor.

5. The power system of claim 1, further comprising switches for controlling the electrical connection of the first excitation source, the second excitation source and a battery for providing additional modes of operation.

6. A method for improving efficiency in a hybrid vehicle, comprising:

accelerating a permanent rotor from a first excitation source providing multiphase excitation;

providing slip energy excitation to a flywheel rotor from a second excitation source;

storing kinetic energy in a flywheel rotor during acceleration of the permanent magnet rotor in which there is magnetic coupling between the flywheel rotor and the permanent magnet rotor; and

operating the first excitation source and the permanent magnet rotor as a generator and returning power through the second excitation source to the flywheel rotor to slow down the permanent magnet rotor.

7. The method of claim 6, wherein the flywheel rotor stores kinetic energy during an initial acceleration to an operating speed and thereafter, through power cycling between the first excitation source and the second excitation source, the flywheel rotor exerts torque on the permanent magnet rotor to provide at least one of a braking mode of operation and an acceleration mode of operation for the permanent magnet rotor.

8. The method of claim 6, wherein the method is practiced in an electric vehicle that does not include an internal combustion engine.