Rotor control for synchronous AC machines
First Claim
1. An AC machine, comprising a:
- an AC machine rotor with a layer of a re-magnetizable high coercive magnetic material provided thereon;
an AC machine stator of a soft, low-loss magnetic material having a pole piece and an excitation coil on said pole piece;
said stator and said rotor rotating relative to one another with a clearance enabling rotor magnetic poles to be selectively reformed on said layer of ret-magnetizable magnetic material by current energizing said excitation coil as said rotor rotates; and
a control signal generator responsive to at least one input signal for generating pulses of programmed wave shapes which are selectively controlled in width, phase and magnitude as necessary to modify at least one of a location, length, and field intensity of said rotor poles for controlling an electrical characteristic of said AC machine.
1 Assignment
0 Petitions
Accused Products
Abstract
An AC machine comprises: a motor energized by an AC source subject to irregularities of frequency and voltage; a generator driven by the motor for supplying an AC output signal of substantially constant frequency and voltage, the generator having a rotor with a layer of a re-magnetizable, relatively high coercive magnetic material on the rotor and a stator of a soft magnetic material having a pole piece and an excitation coil on the pole piece, the stator and the rotor rotating relative to one another with a clearance enabling rotor poles to be formed on the re-magnetizable layer by current energizing the excitation coil; and, a control signal generator responsive to at least one of the AC output signal and a signal representative of the current energizing the excitation coil for generating pulses of programmed wave shapes which differ in at least one of width, phase and magnitude as necessary to modify the rotor poles during the irregularities of the AC source to maintain the substantially constant frequency and voltage of the AC output signal.
32 Citations
34 Claims
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1. An AC machine, comprising a:
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an AC machine rotor with a layer of a re-magnetizable high coercive magnetic material provided thereon; an AC machine stator of a soft, low-loss magnetic material having a pole piece and an excitation coil on said pole piece; said stator and said rotor rotating relative to one another with a clearance enabling rotor magnetic poles to be selectively reformed on said layer of ret-magnetizable magnetic material by current energizing said excitation coil as said rotor rotates; and a control signal generator responsive to at least one input signal for generating pulses of programmed wave shapes which are selectively controlled in width, phase and magnitude as necessary to modify at least one of a location, length, and field intensity of said rotor poles for controlling an electrical characteristic of said AC machine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method for controlling an AC machine, the machine having a rotor with a layer of a re-magnetizable high coercive magnetic material on the rotor and a stator of a soft, low-loss magnetic material having a pole piece and an excitation coil on said pole piece, said stator and said rotor rotating relative to one another with a clearance enabling rotor poles to be selectively re-formed on said re-magnetizable magnetic material as said rotor rotates by current energizing said excitation coil, comprising the steps of:
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automatically supplying pulses of programmed wave shapes to said excitation coil for modifying said rotor poles; and selectively varying said pulses in width, phase and magnitude as necessary to modify at least one of a location, length, and field intensity of said rotor poles for controlling an electrical characteristic of said AC machine. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification