Synchronous motor

摘要

A double-stator synchronous motor has a rotor, an inner stator and an outer stator. The rotor has segment-magnetic poles arranged in a ring shape. Magnetic poles formed in the inner stator and the outer stator face to each other in a same circumferential position. Each stator has q (q≧2) slots per pole and phase to disperse magnetomodive force. A radially minimum width Wr of each segment magnetic pole is within a range of 1.3q to 2.3q times of a minimum width Wt of outer teeth. A magnetic depth of a magnetic concave section formed in the segment magnetic pole is within a range of not less than an average width Ws of the inner slots. Because this suppresses demagnetization in the permanent magnets caused by stator magnetomotive force, ferrite magnets are used as buried magnets and magnetic-pole central magnets, and suppress the amount of neodymium magnet used in the rotor.

主权项

1. A synchronous motor comprising:
a rotor comprising segment magnetic poles made of soft magnetic material arranged in a ring shape in a circumferential direction of the rotor, magnetic concave sections having a magnetic permeability which is lower than a magnetic permeability of the soft magnetic material, and the magnetic concave sections being formed on each of an inner surface and an outer surface of each of the segment magnetic poles; a stator assembly comprising at least a first stator and a second stator, the first stator arranged at an outside of the rotor through a gap, the first stator comprising a plurality of slots and a plurality of first tooth sections formed in the first stator at regular intervals, each first tooth section being formed between the adjacent slots, and a first stator winding being wound around the first tooth sections; and the second stator arranged at an inside of the rotor through a gap, the second stator comprising a plurality of slots and a plurality of second tooth sections formed in a circumferential direction of the second stator at regular intervals, each second tooth section being formed between the adjacent slots, and a second stator winding being wound around the second tooth sections, wherein each of the first stator and the second stator has magnetic poles the number of which is equal to the number of the segment magnetic poles, and the first stator and the second stator generate magnetomotive force so that the magnetic poles in the first stator and the second stator in face-to face relationship have the same magnetic polarity, and the first stator winding and the second stator winding per phase are connected in series with each other, a variable q representing the number of the slots per magnetic pole per phase is an integer not less than two, and a minimum width Wr of the segment magnetic poles is within a range of 1.3q to 2.3q times of a minimum circumferential width Wt of the first tooth sections in the first stator, where the minimum width Wr is a width between the magnetic concave section formed at an outer side of the segment magnetic pole and the magnetic concave section formed at an inner side of the segment magnetic pole, and a depth of each magnetic concave section is not less than an average circumferential width Ws of the slots formed in the second stator.