Structural Optimization Design and Electromagnetic Field Analysis for the Permanent Magnet Power Magnetic Bearing

　　Structural Optimization Design and Electromagnetic Field Analysis for the Permanent Magnet Power Magnetic Bearing
　　Power Magnetic Bearing (PMB) has the ability of self-driven and self-levitated, so it can be non-contact rotation. Due to permanent magnet motor won’t need excitation current of stator winding, and possesses of high efficiency, small size, high power density and other traits, if it is combined with PMB, above advantages will be sufficiently developed, and there will be capacious foreground of applications.In this paper, Permanent Magnet Power Magnetic Bearing http://www.999magnet.com/products/142-neodymium-price (PPMB) is analyzed and optimally designed based on finite element analysis software– ANSYS, aiming at air-gap magnetic field distribution, levitation force, output torque.Two kinds of the electromagnetic force and the operating principle of PPMB are analyzed in detail, and the torque mathematical model and the levitation force analytical model is derived, when the rotor is eccentric.The choice of permanent magnet material and the design of structures of PPMB are accomplished, and the design formula of stator slot and calculation formula of turns are given. The air-gap flux wave of superfical protruding type rotor and built-in tangential type rotor are analyzed based on ANSYS, and the superfical protruding type rotor is selected at last, according to the results of the analysis.The solid model of PPMB is built using ANSYS, the suspending principle of PPMB is proved by analyzing the internal electromagnetic field.
　　The best combination of the two sets of windings is selected due to the value of radial levitation force. The parameters of the prototype is given, furthermore, the relationship of the unilateral magnetic force and the rotor eccentricity, the controllable levitation force and the current of suspension winding, the radial levitation force and the current of suspension winding are obtained, when the rotor is eccentric.The thickness, width, height of stator carcass and air-gap length are optimally designed, and the optimal size of structure of superfical protruding type rotor is obtained, which has the minimum aberration rate of air-gap magnetic field, the maximum radial levitation force, the minimum current of suspension winding and the lest volume of permanent magnet material.