Switched reluctance motor with indirect position sensing and magnetic brake
AssigneeITT Automotive Electrical Systems, Inc.
InventorRoy A. McCann
Life of this patent
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Abstract
A switched reluctance motor includes an auxiliary winding interspersed among the main phase windings such that a constant inductance ratio is established between the main and auxiliary windings regardless of rotor position. The auxiliary winding preferably has a higher inductance compared to the main winding. A test current is injected into the auxiliary winding in order to indirectly determine rotor position and the auxiliary winding is utilized to maintain a holding torque under static load conditions. The disclosed design and methodology improves motor function capabilities and economies.
Claims15
A switched reluctance motor, comprising:
- a rotor that rotates about an axis and has a plurality of rotor poles;
- a stator that is stationary about said axis and generally surrounds said
- rotor, said stator including a plurality of stator poles, said rotor poles moving into and out of alignment with said stator poles when said rotor rotates about said axis;
- a main current conductive coil having a first inductance and being disposed about at least one of said stator poles;
- an auxiliary current conductive coil disposed about said at least one stator pole such that an inductance ratio of said main coil to said auxiliary coil is constant irrespective of a position of said rotor poles relative to said stator poles, said auxiliary coil having a second inductance that is greater than said first inductance;
- a selectively controllable current source for individually energizing said main coil and said auxiliary coil, respectively, to thereby produce a magnetic flux that controls whether said rotor rotates about said axis;
- a voltage sensor for determining a voltage across said auxiliary coil when said auxiliary coil is energized by said current source;
- and
- means for determining a difference in a current phase value associated with a current in said auxiliary coil and a voltage phase value associated with the voltage across said auxiliary coil, said difference being indicative of a position of said rotor pole relative to said stator pole.
A switched reluctance motor, comprising:
- a rotor that rotates about an axis and has a plurality of rotor poles;
- a stator that is stationary about said axis and generally surrounds said
- rotor, said stator including a plurality of stator poles, said rotor poles moving into and out of alignment with said stator poles when said rotor rotates about said axis;
- a main current conductive coil having a first inductance and being disposed about at least one of said stator poles;
- an auxiliary current conductive coil disposed about said at least one stator pole such that an inductance ratio of said main coil to said auxiliary coil is constant irrespective of a position of said rotor poles relative to said stator poles, said auxiliary coil having a second inductance that is greater than said first inductance;
- a selectively controllable current source for individually energizing said main coil and said auxiliary coil, respectively, to thereby produce a magnetic flux that controls whether said rotor rotates about said axis;
- a voltage sensor for determining a voltage across said auxiliary coil when said auxiliary coil is energized by said current source;
- and
- means for determining a difference in a current phase value associated with a current in said auxiliary coil and a voltage phase value associated with the voltage across said auxiliary coil, said difference being indicative of a position of said rotor pole relative to said stator pole wherein said main coil has a plurality of windings wound about said at least one stator pole and said auxiliary coil has a plurality of windings wound about said at least one stator pole such that said auxiliary coil windings are interspersed among said main coil windings.
Dependencies are inferred from the claim text.