Hybrid alternator with full output at idle
First Claim
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, anda 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.
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Accused Products
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.
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Citations
2 Claims
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1. An alternator comprising:
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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.
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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:
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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.
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Specification