Hybrid alternator with full output at idle

• US 5,710,471 A
• Filed: 06/02/1995
• Issued: 01/20/1998
• Est. Priority Date: 06/14/1993
• Status: Expired due to Fees

• Current Assignee: Ecoair Corp.
• Original Assignee: Ecoair Corp.
• Inventors: Syverson, Charles D., Curtiss, William P.
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): WALLACE, MICHAEL J
• Application Number:
  US08/460,037
• Time in Patent Office: 963 Days
• Field of Search: 310/114, 310/263, 310/52, 310/58, 310/60 A, 310/65, 310/266, 310/181, 322/28, 322/29, 322/46
• US Class Current: 310/114
• CPC Class Codes: H02H 7/067 on occurrence of a load dump control on sudden change of load H02P9/10
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: H02J 7/163 with special means for initiating or limiting the excitation current
• CPC Class Codes: H02J 7/28 using magnetic devices with controllable degree of saturation in combination with controlled discharge tube or controlled semiconductor device
• CPC Class Codes: H02K 1/24 Rotor cores with salient poles ; Variable reluctance rotors
• CPC Class Codes: H02K 1/2713 the magnetisation axis of the magnets being axial, e.g. claw-pole type
• CPC Class Codes: H02K 1/276 Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM]
• CPC Class Codes: H02K 1/2773 consisting of tangentially magnetized radial magnets
• CPC Class Codes: H02K 16/00 Machines with more than one rotor or stator machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029
• CPC Class Codes: H02K 16/02 Machines with one stator and two or more rotors
• CPC Class Codes: H02K 19/103 Motors having windings on the stator and a variable reluctance soft-iron rotor without windings
• CPC Class Codes: H02K 19/28 for self-excitation
• CPC Class Codes: H02K 19/36 Structural association of synchronous generators with auxiliary electric devices influencing the characteristic of the generator or controlling the generator, e.g. with impedances or switches
• CPC Class Codes: H02K 19/365 with a voltage regulator
• CPC Class Codes: H02K 21/042 with permanent magnets and field winding both rotating
• CPC Class Codes: H02K 3/51 applicable to rotors only
• CPC Class Codes: H02K 9/06 with fans or impellers driven by the machine shaft
• CPC Class Codes: H02P 2101/45 : for motor vehicles, e.g. car alternators
• CPC Class Codes: H02P 25/16 : characterised by the circuit arrangement or by the kind of wiring
• CPC Class Codes: H02P 9/305 : controlling voltage H02P9/302 takes precedence
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries

Abstract

A hybrid alternator includes a stator and a rotor, with the rotor having longitudinally separate wound field and permanent magnet rotor portions. A rotor excitation circuit applies a forward polarity to the wound field rotor portion to increase output in a boosting mode at low RPMs and a reverse polarity to decrease output at high RPMs in a bucking mode to maintain a constant voltage output. Alternative embodiments combine a magnetic flux concentrating design for efficient low speed operation with integral strength for high speed capability. Dual voltage output is provided either through dual stator windings or through a voltage converter circuit. Single voltage output is provided using only one stator winding. A three state voltage regulator allows voltage regulation without inducing reverse currents onto the power bus in the lightly loaded or no battery conditions.

Claims

1. An alternator comprising:

a rotor mounted for rotation on a shaft; and

a stator surrounding the rotor and separated therefrom by an air gap, the stator having a first longitudinal region formed of magnetic material and a second longitudinal region formed of magnetic material, the second longitudinal region being magnetically separated from the first longitudinal region by a stator gap having one or more cooling air passages, the cooling air passages allowing radial air flow of ambient cooling air from a point directly outside the alternator to a point within the stator gap between the first and second longitudinal regions of the stator and then into the air gap between the stator and the rotor;

the rotor including;

a wound field rotor portion mounted on the shaft for rotation within the first longitudinal region of the stator, the wound field rotor portion having a rotor winding, and

a permanent magnet rotor portion mounted on the shaft in longitudinally spaced relation to the wound field rotor portion for rotation within the second longitudinal region of the stator the permanent magnet rotor portion having a plurality of magnetic poles.

2. A hybrid alternator adapted for supplying a rated output current to electrical devices in a vehicle powered by an engine with an engine idling speed and an engine maximum speed comprising:

a stator having a stator winding and a stator winding output;

a rotor mounted for rotation within the stator, the rotor including;

a shaft mounted for rotation within the stator,

a wound field rotor portion mounted on the shaft for rotation within the stator, the wound field rotor portion having a rotor winding, and

a permanent magnet rotor portion mounted on the shaft for rotation within the stator, the permanent magnet rotor portion having at least one permanent magnet;

a voltage rectifier circuit connected to the stator winding output, the voltage rectifier circuit having a voltage rectifier output producing an output voltage for the hybrid alternator; and

a voltage regulator connected to the voltage rectifier output for regulating the output voltage of the hybrid alternator by switching a forward polarity voltage and a reverse polarity voltage to the rotor winding;

the alternator producing the rated output current when the vehicle engine is operating at the engine idling speed by switching the forward polarity voltage to the rotor winding and producing the rated output current when the vehicle engine is operating at the engine maximum speed by switching the reverse polarity voltage to the rotor winding.