Magnetic Flux Detecting Of Bearingless Induction Motors With Search Coils

The magnetic force of bearingless induction motors is generated with two kinds of magnetic fields interaction. The levitated mechanism determines the strong coupling relation between the air-gap flux of drive winding and that of levitation winding. Then it is very important to estimate or detect the distribution of magnetic flux. In this paper, as different positions of search coils are concerned, three methods of detecting the air gap flux density are analyzed in detail: evenly distributed angle position method, typical angle position method and analytic method. Moreover, the principle of the levitated force production is introduced. The control system configuration is proposed. At last, parameters of the motor prototype are given. The experimental results verify the validity of the proposed methods.