Speed monitoring and control for a brushless motor
First Claim
1. A speed monitoring and control method for a brushless motor, said motor having a rotor and a stator, said stator having a plurality of coils connected with a neutral node, said stator further coupled to a plurality of line voltages, said motor controlled by a controller which provides switching control signals to a plurality of switching elements, said method comprising:
- comparing one said line voltage with a signal representing a voltage at said neutral node, to generate a comparison signal; and
ANDing said comparison signal with a said switching control signal to generate a composite feedback signal representative of a rotational speed of said rotor relative to a speed of a rotating magnetic field generated by said stator.
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Accused Products
Abstract
A speed monitoring and control method for a brushless motor controlled by a controller which provides switching control signals to a plurality of switching elements includes comparing one line voltage of the motor with a signal representing a voltage at the neutral node of the motor, to generate a comparison signal. The method also includes ANDing the comparison signal with a switching control signal to generate a composite feedback signal representative of a rotational speed of the motor'"'"'s rotor relative to a speed of a rotating magnetic field generated by the stator.
21 Citations
11 Claims
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1. A speed monitoring and control method for a brushless motor, said motor having a rotor and a stator, said stator having a plurality of coils connected with a neutral node, said stator further coupled to a plurality of line voltages, said motor controlled by a controller which provides switching control signals to a plurality of switching elements, said method comprising:
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comparing one said line voltage with a signal representing a voltage at said neutral node, to generate a comparison signal; and ANDing said comparison signal with a said switching control signal to generate a composite feedback signal representative of a rotational speed of said rotor relative to a speed of a rotating magnetic field generated by said stator. - View Dependent Claims (2, 3, 4)
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5. A speed monitoring and control apparatus for a brushless motor, said motor having a rotor and a stator, said stator having a plurality of coils connected with a neutral node, said apparatus comprising:
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a controller coupled to a plurality of switching elements and adapted to provide switching control signals to said switching elements to generate line voltages for said stator; an electrical node representing said neutral node; comparison means coupled to compare a voltage at said electrical node with a said line voltage of said motor to generate a comparison signal; ANDing means for ANDing said comparison signal with a said switching control signal to generate a feedback signal having a characteristic representative of a rotational speed of said rotor relative to a rotational speed of a rotating magnetic field generated by said stator. - View Dependent Claims (6, 7, 8, 9)
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10. A speed monitoring and control apparatus for a brushless motor, said motor having a rotor and a stator, said stator having a plurality of coils connected with a neutral node said apparatus comprising:
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an electrical node representing said neutral node; comparison means coupled to compare a voltage at said electrical node with a said line voltage of said motor to generate a comparison signal; and means for generating a signal having a pulse width representative of a rotational speed of said rotor relative to a rotational speed of a magnetic field generated by said stator. - View Dependent Claims (11)
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Specification