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US 8,552,609 B2Granted
Synchronous motor and system for driving synchronous motor
AssigneePanasonic Corporation
InventorNoriyoshi Nishiyama
Life of this patent
Estimating the term…
Abstract
A synchronous motor which has reduced torque ripple while having a high torque includes a rotor and a stator, and U-phase coils, V-phase coils, and W phase coils are wound around sections of the yoke each located between two adjacent stator teeth. The number of turns in each coil and the direction in which each coil is wound are set to compensate for a difference between a timing at which a magnetic field produced at each stator tooth is at a maximum value and a timing at which a point between magnetic poles passes by the stator tooth as the rotor rotates, the difference in timing being caused by a difference between the interval between the magnetic poles and the interval between the stator teeth.
Claims22
A synchronous motor comprising:
- a rotor having a plurality of magnetic poles arranged around a circumference of the rotor at an equal interval;
- and
- a stator having a plurality of stator teeth arranged around a circumference of the stator, the stator teeth radially protruding from an annular yoke of the stator and differing in number from the magnetic poles, wherein
- the stator teeth form a plurality of stator teeth groups, each of the stator teeth groups including a predetermined number of stator teeth consecutive around the circumference of the stator, and the stator teeth groups being arranged circumferentially at an equal interval,
- the predetermined number of stator teeth are arranged at an interval different from the interval of the magnetic poles of the rotor,
- for each stator tooth among the predetermined number of stator teeth, a main coil included in a coil of one phase is wound around at least one of two sections of the yoke respectively located between the stator tooth and a stator tooth adjacent on either side,
- in at least one of the predetermined number of stator teeth in a certain stator teeth group, in addition to the main coil, a sub-coil included in a coil of a different phase than the one phase is wound around the at least one of two sections of the yoke,
- the sub-coil is connected in series with the main coil included in another stator teeth group located at a different electrical angle than the certain stator teeth group,
- the number of turns in each coil and a direction in which each coil is wound are set to compensate for a difference between a timing at which a magnetic field produced at each stator tooth by applying alternating current to each coil is at a maximum value and a timing at which a point between adjacent magnetic poles passes by the stator tooth as the rotor rotates,
- in each stator teeth group, only the main coil is wound in correspondence with a first stator tooth among the predetermined number of stator teeth, and the main coil and the sub-coil are wound in correspondence with a second stator tooth adjacent to the first stator tooth, and
- a coil ratio between the main coil and the sub-coil wound in correspondence with the second stator tooth is set so that when the first stator tooth and the magnetic poles of the rotor are in a predetermined positional relationship, the magnetic field produced at the first stator tooth is at the maximum value, and when the rotor rotates so that the second stator tooth and the magnetic poles of the rotor are in the same positional relationship as the predetermined positional relationship, the magnetic field produced at the second stator tooth is at the maximum value.
8 more elements
A synchronous motor driving system formed by a synchronous motor and a corresponding actuator device, wherein
- the synchronous motor comprises:
- a rotor having a plurality of magnetic poles arranged around a circumference of the rotor at an equal interval;
- and
- a stator having a plurality of stator teeth arranged around a circumference of the stator, the stator teeth radially protruding from an annular yoke of the stator and differing in number from the magnetic poles, wherein
- the stator teeth form a plurality of stator teeth groups, each of the stator teeth groups including a predetermined number of stator teeth consecutive around the circumference of the stator, and the stator teeth groups being arranged circumferentially at an equal interval,
- the predetermined number of stator teeth are arranged at an interval different from the interval of the magnetic poles of the rotor,
- for each stator tooth among the predetermined number of stator teeth, a main coil included in a coil of one phase is wound around at least one of two sections of the yoke respectively located between the stator tooth and a stator tooth adjacent on either side,
- in at least one of the predetermined number of stator teeth in a certain stator teeth group, in addition to the main coil, a sub-coil included in a coil of a different phase than the one phase is wound around the at least one of two sections of the yoke,
- the sub-coil is connected in series with the main coil included in another stator teeth group located at a different electrical angle than the certain stator teeth group,
- the number of turns in each coil and a direction in which each coil is wound are set to compensate for a difference between a timing at which a magnetic field produced at each stator tooth by applying alternating current to each coil is at a maximum value and a timing at which a point between adjacent magnetic poles passes by the stator tooth as the rotor rotates,
- in each stator teeth group, only the main coil is wound in correspondence with a first stator tooth among the predetermined number of stator teeth, and the main coil and the sub-coil are wound in correspondence with a second stator tooth adjacent to the first stator tooth, and a coil ratio between the main coil and the sub-coil wound in correspondence with the second stator tooth is set so that when the first stator tooth and the magnetic poles of the rotor are in a predetermined positional relationship, the magnetic field produced at the first stator tooth is at the maximum value, and when the rotor rotates so that the second stator tooth and the magnetic poles of the rotor are in the same positional relationship as the predetermined positional relationship, the magnetic field produced at the second stator tooth is at the maximum value.
8 more elements
A synchronous motor comprising:
- a rotor having a plurality of magnetic poles arranged around a circumference of the rotor at an equal interval;
- and
- a stator having a plurality of stator teeth arranged around a circumference of the stator, the stator teeth radially protruding from an annular yoke of the stator and differing in number from the magnetic poles, wherein
- the stator teeth form a plurality of stator teeth groups, each of the stator teeth groups including a predetermined number of stator teeth consecutive around the circumference of the stator, and the stator teeth groups being arranged circumferentially at an equal interval,
- the predetermined number of stator teeth are arranged at an interval different from the interval of the magnetic poles of the rotor,
- for each stator tooth among the predetermined number of stator teeth, a main coil included in a coil of one phase is wound around at least one of two sections of the yoke respectively located between the stator tooth and a stator tooth adjacent on either side,
- in at least one of the predetermined number of stator teeth in a certain stator teeth group, in addition to the main coil, a sub-coil included in a coil of a different phase than the one phase is wound around the at least one of two sections of the yoke,
- the sub-coil is connected in series with the main coil included in another stator teeth group located at a different electrical angle than the certain stator teeth group,
- the number of turns in each coil and a direction in which each coil is wound are set to compensate for a difference between a timing at which a magnetic field produced at each stator tooth by applying alternating current to each coil is at a maximum value and a timing at which a point between adjacent magnetic poles passes by the stator tooth as the rotor rotates,
- wherein the sub-coil and the main coil are part of a plurality of stator coils which form stator coil groups, each stator coil group including m stator coils, wherein the m stator coils in each stator coil group are arranged at an equal interval differing from the interval between the magnetic poles of the rotor.
7 more elements
Dependencies are inferred from the claim text.