Characteristic analysis of bi- and uni-polar reluctance motor drives

✍ Scribed by Takashi Kosaka; Yo-ichi Taniguchi; Nobuyuki Matsui

• Book ID: 101292760
• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 325 KB
• Volume: 123
• Category: Article
• ISSN: 0424-7760
• DOI: 10.1002/(sici)1520-6416(199805)123:3<64::aid-eej8>3.0.co;2-o

✦ Synopsis

Comparative studies on the torque characteristics of reluctance motors for bi-and uni-polar sinusoidal drives are given. A 3-phase test motor with 6/8 stator and rotor pole combination is used for nonlinear FEM analysis and experiments. The analysis shows that different flux paths are produced, by bi-and uni-polar current drives, which makes two significant differences in torque-current characteristics. Since the unipolar current drive produces a shorter flux path, and therefore a higher air-gap flux density, higher torque for a given winding current can be expected. Another important issue is the effect of magnetic saturation. Examination of the yoke flux at various rotor angles suggests that the yoke is apt to be saturated in bipolar current drive.

Experimental verification was made with a test motor. From these experiments and analysis, it is concluded that unipolar sinusoidal current drive should preferably have a linear relation between torque and current and should avoid the effect of magnetic saturation.