Principle and Performance Analysis for Heterpolar Permanent Magnet Biased Radial Hybrid Magnetic Bearing

In order to solve the nonlinear problem and strong coupling of three-pole magnetic bearings, a heterpolar permanent magnet biased radial structure is proposed. Firstly, the structure and working principle of the heterpolar permanent magnet biased radial hybrid magnetic bearing are introduced, and the mathematical models of suspension forces are established by the equivalent magnetic circuit method. Secondly, in the case of the same volume and the same ampere-turn, the force-current characteristics and maximum carrying capacity of the couple-piece type three-pole structure and the heterpolar permanent magnet biased radial structure are obtained through theoretical analysis and 3D finite element method (FEM) analysis, respectively, and the data obtained are analyzed and compared. Finally, the theory analysis and experiment results show that compared with the couple-piece type three-pole structure, the nonlinearity among the suspension forces and the control currents of the heterpolar permanent magnet biased radial structure is obviously reduced, and the maximum bearing capacity of the heterpolar permanent magnet biased radial structure is increased by 29.4%, which proves the rationality of the radial heterpolar permanent magnet biased radial structure and parameters.