Driving device for polyphase motor
AssigneeAlps Electric Co., Ltd.
InventorMasayoshi Nakagawa
Life of this patent
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Abstract
Within a three-phase motor M, there are mounted one chip-shaped magnetoresistance effect element sensors comprising magnetoresistance effect elements having a spin-valve structure in series connected. The driving signal generating means generates difference signals obtained by subtracting output signals from each of the magnetoresistance effect element sensors. The phase current supplying means generates phase currents on the basis of the difference signals, and supplies these to driving coils for each phase respectively. The magnetoresistance effect element sensor is more excellent in temperature characteristic than the hole element, and is also high in output level, and therefore, the rotational speed and phase of the three-phase motor can be maintained with high accuracy.
Claims8
A driving device for a polyphase-motor, comprising:
- a polyphase motor having a rotor magnet and a stator having a plurality of driving coils, each driving coil corresponding to a phase of a plurality of phases of the polyphase motor, the rotor magnet rotating when each phase current of a plurality of phase currents is supplied to the stator;
- a magnetoresistance effect element sensor provided for each phase of the plurality of phases, each magnetoresistance effect element sensor to detect an output signal corresponding to a rotational phase of said rotor magnet and having an output signal with an offset voltage;
- an offset remover to remove the offset voltage of each output signal from said magnetoresistance effect element sensor;
- a driving signal generator to generate a difference signal between phases of said output signal corresponding to each phase of the polyphase motor, from which said offset voltage has been removed;
- and
- a phase current generator to generate phase current applied to the plurality of driving coils for each phase on the basis of said difference signal.
A driving device for a polyphase motor, comprising:
- a polyphase motor having a rotor magnet and a stator having a plurality of driving coils, each driving coil corresponding to a phase of a plurality of phases of the polyphase motor, the rotor magnet rotating when each phase current of a plurality of phase currents is supplied to the stator;
- a magnetoresistance effect element sensor provided for each phase of the plurality of phases, each magnetoresistance effect element sensor to detect an output signal corresponding to a rotational phase of said rotor magnet and having an output signal with an offset voltage;
- a driving signal remover to remove the offset voltage of each output signal from said magnetoresistance effect element sensor and to generate a difference signal between phases of said output signal corresponding to each phase of the polyphase motor, from which said offset voltage has been removed;
- and
- a phase current generator to generate phase current applied to the plurality of driving coils for each phase on the basis of said difference signal.
Dependencies are inferred from the claim text.