Control of an electrical machine
AssigneeSwitched Reluctance Drives Limited
InventorSteven Paul Randall
Life of this patent
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Abstract
A switched reluctance machine has salient poles on the stator and rotor. The windings of the machine are supplied from a converter which provides energization at a chosen rate. The windings of the machine may be energized at the rate at which the rotor poles pass the stator poles, or it may be operated at a fraction of that rate by energizing the windings to cooperate with every second, third or fourth rotor pole. This can extend the output of the machine.
Claims20
A method of operating an electrical machine, the machine having
- a stator defining stator poles,
- a rotor defining rotor poles, the rotor being movable relative to the stator so that the rotor poles are successively alignable with any stator pole,
- and independently energisable phase windings, each associated with at least a pair of stator poles and having an inductance cycle determined by the passage of the rotor poles past the stator poles, the method comprising:
- in a first mode of operation, initiating the energisation of the phase windings in a predetermined sequence and for consecutive inductance cycles of each phase in turn;
- and
- in a second mode of operation, initiating the energisation of the phase windings in the same sequence, in which initiation of energisation of each phase winding is followed by at least one inductance cycle of that phase with no initiation of energisation.
A switched reluctance drive system comprising:
- a stator defining stator poles;
- a rotor defining rotor poles, the rotor being movable relative to the stator so that the rotor poles are successively alignable with any stator pole;
- independently energisable phase windings each associated with at least a pair of stator poles and having an inductance cycle determined by the passage of the rotor poles past the stator poles;
- a controller operable to initiate the energisation of the phase windings in a predetermined sequence, the initiation of the energisation of the phase windings occurring in some part of consecutive inductance cycles of the windings in turn in a first mode of operation, and energisation of the phase windings being initiated in the same sequence in which initiation of each phase winding being followed by at least one inductance cycle of that phase with no initiation of energisation, in a second mode of operation.
A method of operating an electrical machine, the machine having
- a stator defining stator poles,
- a rotor defining rotor poles, the rotor being movable relative to the stator so that the rotor poles are successively alignable with any stator pole, and
- independently energisable phase windings, each associated with at least a pair of stator poles and having an inductance cycle determined by the passage of the rotor poles past the stator poles, the method comprising:
- in a first mode of operation initiating energisation of the phase windings in a predetermined sequence, in which the rate of initiating energisation is equal to the rate at which the rotor poles coincide with a given stator pole, and
- in a second mode of operation initiating energisation of the phase windings in the same sequence, in which the rate of initiating energisation of the phase windings is less than the rate at which the rotor poles coincide with the given stator pole.
Dependencies are inferred from the claim text.