Method and system for determining rotor position in a switched reluctance machine
AssigneeSwitched Reluctance Drives Limited
InventorsHoward James Slater, Rosemary Anne Norman
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Abstract
A switched reluctance machine is controlled without using a physical rotor position detector. The rotor position at start-up is determined by simultaneously injecting a current of known magnitude into two phases. The rise times of the currents are measured and used to interrogate a stored table of rise time against rotor angle for the known current level. This produces two possible rotor positions from each rise time. Comparisons of the pairs of angles yield the actual position.
Claims26
A method for determining the position of a rotor relative to a stator of a polyphase switched reluctance machine, the method comprising:
- energizing at least two phases coincidentally;
- monitoring the rise time of current in each of the phases to a predetermined threshold;
- equating the rise time of current in each phase to possible positions of the rotor due to cyclical variations in inductance in each phase with rotor position;
- and
- comparing the possible positions of the rotor for substantial agreement between them to derive the actual rotor position.
A system for determining the position of a rotor relative to a stator of a polyphase switched reluctance machine, the system comprising:
- means for energizing at least two phases coincidentally;
- means for monitoring the rise time of current in each of the phases to a predetermined threshold;
- means for equating the rise time of current in each phase to possible positions of the rotor due to cyclical variations in inductance in each phase with rotor position;
- and
- means for comparing the possible positions of the rotor for substantial agreement between them to derive the actual rotor position.
Dependencies are inferred from the claim text.