Electricity: motive power systems – Synchronous motor systems – Hysteresis or reluctance motor systems
Patent
1995-06-08
1997-04-08
Wysocki, Jonathan
Electricity: motive power systems
Synchronous motor systems
Hysteresis or reluctance motor systems
318254, H02P 700
Patent
active
056191138
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a reluctance type motor having a large output and a small torque ripple and, therefore, preferably used as a driving source, for example, for electric cars, electric bioycles, cranes, electric cleaners, and the like.
BACKGROUND ART
Despite its large output torque, a reluctance type motor has so various disadvantages including low rotational speed and vibration that it has scarcely been practically utilized.
A first problem to be solved in the reluctance type motor is as follows: since the magnetic path of armature coils, formed in salient poles and magnet poles, is almost closed, the inductance of the reluctance type motor is very large. This increases magnetic energy amount stored into or discharged from magnetic poles or salient poles. And also this increases the repetition frequency of such energy storage and discharge during one complete revolution of the rotor. There is, therefore, a problem that the reluctance type motor cannot rotate in a high-speed region despite of outputting large output torque. Solving the above-described problem becomes difficult with increasing output of a reluctance type motor.
A second problem is as follows: FIG. 1 shows a plan view showing a well-known three-phase half-wave current supply mode reluctance type motor. A reference numeral 16 represents a fixed armature which is made of laminated layers of silicon steel sheets. Magnetic poles 16a, 16b, --are associated with armature coils 17a-1, 17b-1, --. A rotor 1 rotates in a direction of an arrow A. A reference numeral 5 represents a rotational shaft 5. When armature coils 17b-1, 17e-1 are activated, the rotor 1 rotates in the direction of the arrow A. After 120-degree rotation, these armature coils are deactivated. Next, armature coils 17c-1, 17f-1 are activated. After 120-degree rotation, these armature coils are deactivated.
As described above, the rotor 1 rotates in the order of the armature coils 17a-1, 17d-1.fwdarw.17b-1, 17e-1.fwdarw.17c-1, 17f-1 along the arrow A. Only two salient poles contribute to generation of the above-described rotational torque, and remaining four salient poles have no relation to this generation of rotational torque. If all the six salient poles generate torque simultaneously, a generated torque will be increased three times. However, this is not attainable.
Furthermore, a third problem is as follows: when the armature coils 17a-1, 17d-1 are activated, the magnetic poles 16a, 16d are magnetically attracted radially toward the salient poles 1a, 1e. Thus, the fixed armature 16 causes deformation due to this attraction force. When the rotor rotates, the fixed armature causes deformation due to another attraction forces generated by the magnetic poles 16b, 16e and 16c, 16f and their confronting salient poles. These deformation mechanism induces the vibration of the motor. As it is technically difficult to equalize the air gap length between salient poles and magnetic poles, an attraction force received by the rotor 1 changes its direction as the rotor 1 rotates. Thus, the rotor 1 causes vibration in the radial direction. Accordingly, vibration noise is generated. And, the durability of the bearing, provided for the rotational shaft of the rotor 1, is worsened. In the case of a large-output motor, it becomes difficult to solve the above-described problems.
Furthermore, a fourth problem is as follows. When the above-described second problem is solved, it will encounter with a large ripple torque as described later with reference to FIG. 11.
Accordingly, the present invention has an object to provide a reluctance-type motor capable of suppressing vibration, rotating at high speeds, generating a large output torque and bringing flat torque characteristics.
In order to accomplish above purpose, a first aspect of the present invention provides a reluctance type motor in a three-phase full-wave reluctance type motor, comprising: n first and second salient poles having the same width, equally spaced at regular angles and disposed at both ends of an ou
REFERENCES:
patent: 3980933 (1976-09-01), Piatkowski, Jr.
patent: 4684867 (1987-08-01), Miller et al.
patent: 5075610 (1991-12-01), Harris
patent: 5115181 (1992-05-01), Sood
patent: 5223779 (1993-06-01), Palaniappan
patent: 5278482 (1994-01-01), Bahn
patent: 5341076 (1994-08-01), Bahn
patent: 5485047 (1996-01-01), Bahn
Kabushikigaisha Sekogiken
Wysocki Jonathan
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