Rotational direction detecting apparatus for a three-phase brushless DC motor
AssigneeDenso Corporation
InventorYoshitaka Hayashi
Life of this patent
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Abstract
A region judging circuit judges an electric angle region of a three-phase brushless DC motor based on an output signal of a resolver. A latch timing output circuit determines an optimum latch timing. A driving direction judging circuit judges a rotational direction of the motor based on a comparison in largeness between a pair of phase currents. A latch circuit latches a judgement result of the driving direction judging circuit at the latch timing designated by the latch timing output circuit and retains the judgement result until the next latch timing comes.
Claims2
A rotational direction detecting apparatus for a three-phase brushless DC motor, comprising:
- current sensors for detecting current values flowing across two of three-phase windings of the three-phase brushless DC motor,
- comparing means for comparing two current values detected by said current sensors,
- rotational angle detecting means for outputting a signal representing a rotational angle of said three-phase brushless DC motor,
- timing judging means for judging a latch timing based on said rotational angle detected by said rotational angle detecting means so that a compared result produced from said comparing means reflects a correct rotational direction, and
- latch means for inputting said compared result obtained from said comparing means at said latch timing based on an output signal of said timing judging means as a signal representing a rotational direction of said three-phase brushless DC motor, and for retaining the detected rotational direction until the next latch timing comes.
Dependencies are inferred from the claim text.