Electrical machine and method of controlling the same
AssigneeA. O. Smith Corporation
InventorsPaul Steven Mullin, Brian Thomas Branecky
Life of this patent
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Abstract
An electrical machine having a stator and a rotor. The stator includes a core and a plurality of windings disposed on the core in a multiple-phase arrangement. The rotor is disposed adjacent to the stator to interact with the stator. A method of operating the motor includes applying a pulsed voltage differential to first and second terminals of the windings resulting in movement of the rotor; monitoring the back electromotive force (BEMF) of the windings to sense rotor movement; after the applying and monitoring steps, monitoring the BEMF of the windings to determine whether the rotor is rotating in a desired direction, and electrically commutating the motor when the rotor is rotating in the desired direction and zero or more other conditions exist.
Claims30
A method for controlling an electrical machine having a stator and a rotor, the stator including a core having a plurality of phase windings disposed on the core, the rotor disposed adjacent to the stator and including a plurality of magnetic poles such that the rotor is misaligned at an unknown position with respect to the stator, the method comprising:
- generating a first moving force to cause rotation of the rotor with respect to the stator from the unknown position;
- thereafter generating a first braking force to at least slow rotation of the rotor with respect to the stator;
- thereafter generating a second moving force for rotating the rotor with respect to the stator;
- and
- thereafter generating a second braking force for stopping rotation of the rotor at a known position with respect to the stator.
Dependencies are inferred from the claim text.