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US 7,622,882 B2Granted
Position detection device for permanent magnetic machines
AssigneeMagna Electronics Inc.
InventorsLei Hao, Zilai Zhao
Life of this patent
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Abstract
The invention indicates a correct one of multiple rotor positions. For example, the invention can determine, in a PM machine, which of two possible positions a rotor is in when the position is known only within ±π radians. If the actual rotor position is known to be one of ω and ω+π, for example as indicated by a resolver, the proposed invention can be used to determine whether the actual position is ω or ω+π.
Claims3
A permanent magnet machine, comprising:
- a motor with a stator having cores with windings thereon and a rotor, which is movable relative to the stator, having permanent magnets, the motor having an odd number of pole pairs;
- a resolver configured to indicate an even number of pole pair positions, whereby upon start-up the resolver identifies a rotor position ambiguous by a predetermined value;
- and
- a controller configured to receive a position signal from the resolver and generating a driving signal for moving the motor and wherein, upon start-up, the controller is configured to
- (i) pulse a first voltage pattern to the windings in the form of the drive signal corresponding to a presumed rotor position and obtain a first measurement of current in the windings resulting from the application of the first voltage pattern,
- (ii) pulse a second voltage pattern, opposite of the first voltage pattern, and obtain a second measurement of current in the windings resulting from the application of the second voltage pattern, and
- (iii) compare the first and second current measurements to resolve said rotor position ambiguity.
4 more elements
Dependencies are inferred from the claim text.