VSCF start system motor current estimator
First Claim
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1. A current estimator for a motor having a rotor and a stator having a stator coil which is energized from a source of power for imparting rotation to the rotor, comprising:
- first sensing means for sensing the speed of rotational movement of the rotor;
second sensing means for sensing the power drawn by the stator coil from the source of power;
means for determining motor torque angle; and
means coupled to said first and second sensing means and said determining means for calculating an estimation of the current through the stator coil responsive to said rotor speed, said power drawn by the stator coil, and said torque angle.
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Abstract
The problem of excess size and weight resulting from the use of current sensors in a VSCF start system (10) is solved by a motor control (22) which utilizes a current estimator (68) to develop a current feedback value. The current estimator (68) is coupled to a rotor position detector (72) and an input power detector (78) and receives a signal representing motor torque angle to develop a signal representing the estimated current drawn by the motor (12).
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Citations
16 Claims
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1. A current estimator for a motor having a rotor and a stator having a stator coil which is energized from a source of power for imparting rotation to the rotor, comprising:
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first sensing means for sensing the speed of rotational movement of the rotor; second sensing means for sensing the power drawn by the stator coil from the source of power; means for determining motor torque angle; and means coupled to said first and second sensing means and said determining means for calculating an estimation of the current through the stator coil responsive to said rotor speed, said power drawn by the stator coil, and said torque angle. - View Dependent Claims (2, 3, 4)
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5. A control for a brushless electro-motive machine having a rotor and a stator having a stator coil which is controllably energized from a source of power for imparting rotation to the rotor, comprising:
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first sensing means for sensing the speed of rotational movement of the rotor; second sensing means for sensing the power drawn by the stator coil from the source of power; means for determining motor torque angle; means coupled to said first and second sensing means and said determining means for calculating an estimation of the current through the stator coil responsive to said speed of the rotor, said power drawn by the stator coil, and said torque angle; and control means coupled to said calculating means for controllably energizing the stator coil responsive to the current estimation. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A start control for a motor having a rotor and a stator having a stator coil which is controllably energized from a source of DC power defining a positive and a negative DC voltage for imparting rotation to the rotor, comprising:
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first sensing means for sensing the speed of rotational movement of the rotor and generating a signal representative thereof; second sensing means for sensing the power drawn by the stator coil from the source of DC power and generating a signal representative thereof; switching means coupled between the source of DC power and the stator coil for alternately applying a positive and a negative voltage to the stator coil; means for developing a signal representing motor torque angle; means coupled to said first and second sensing means and said developing means for generating a signal representing an estimation of the current through the stator coil responsive to said rotor speed, said power drawn by the stator coil, and said torque angle; and control means coupled to said generating means for controllably operating said switching means responsive to the current estimation. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification