Method and an arrangement for starting an electrical machine having varying reluctance
AssigneeEmotron Aktiebolag
InventorPer Zellman
Life of this patent
Estimating the term…
Abstract
An electric variable reluctance machine having at least three phase circuits with varying reluctance depending on the position of a movable part, made of soft magnetic material, in relation to a stationary part. The phase circuit values having a clear relationship with the reluctance values of the machine are detected and used to select which of the phase circuits are to be activated in order to provide torque in a desired direction. The selected phases are activated in sequence by control pulses from a control unit.
Claims9
A method for starting an electric variable reluctance machine of a kind having three or more phase circuits (Phase 1, Phase 2, Phase 3, F1, F2, F3) with varying reluctance in dependence on the position of a movable part, made of soft magnetic material, in relation to a stationary part of the machine,
- the method comprising the steps of:
- dividing a reluctance cycle of the machine into a number of rotor position angular zones (zone 1-zone 6), where there is a clear relationship between said phase circuit values within each zone;
- defining rotor position angular zone boundaries as zone positions in which two phases have equally large phase circuit values;
- determining said phase circuit values (L.sub.PHASE1, L.sub.PHASE2, L.sub.PHASE3) which are relevant among said phase circuits (F1, F2, F3);
- establishing by comparison a mutual order of magnitude of the determined values, and therewith establishing the zone which discloses the position of the movable part in relation to the stationary part;
- and
- activating at least one circuit (F1, F2, F3) which produces driving in the desired direction, based on the established zone.
An arrangement for starting an electrical variable reluctance machine of a kind having at least three phase circuits with varying reluctance in dependence on a position of a movable part, made of soft magnetic material, in relation to a stationary part of the machine, so as to enable selection of at least one phase circuit which shall be activated in order to provide torque in a desired direction, said arrangement comprising a calculating and control unit (1) which is connected to control means (Ta1, Tb1;
- Ta2, Tb2;
- Ta3, Tb3) for the different phase circuits and which is connected to detect phase circuit values having a clear relationship with reluctance values of the machine,
- wherein a reluctance cycle of the machine is divided into a number of rotor position angle zones where a clear relationship between said phase circuit values is found within each zone;
- said calculating and control unit (1) functions to
- in sequence, determine values for relevant phase circuits, thereby determining at least three phase circuit values, among said phase circuits,
- and thereafter functions to establish a mutual order of magnitude between said determined values, and
- functions to define rotor position angular zone boundaries as zone positions in which two phases have equally large phase circuit values;
- and functions to establish the rotor position zone within which said movable part of the machine is located in relation to said stationary part;
- and
- wherein said calculating and control unit (1), on the basis of the established rotor position zone and a position between the movable part of the machine in relation to the stationary part thereof indicated by said established zone, activates at least one phase circuit which provides driving in a desired direction.
Dependencies are inferred from the claim text.