Modeling and Multilevel Design Optimization of an AC–DC Three-Degree-of-Freedom Hybrid Magnetic Bearing

In this article, in order to improve the bearing capacity per unit area and reduce the nonlinearity and couplings of three-pole magnetic bearing, which is driven by a three-phase power inverter, a three-degree-of-freedom (3-DOF) six-pole hybrid magnetic bearing (HMB) is proposed. To realize the larger bearing capacity and smaller volume, a multilevel design optimization is proposed to conduct multiobjective optimization. At first, the structure and working principle of the ac–dc 3-DOF six-pole HMB are introduced. Then, the suspension force mathematical models of the 3-DOF HMB based on the Maxwell tensor method are established. Next, the design variables and optimization objectives are selected, and the comprehensive sensitivity analysis is adopted to divide the design variables into three levels; the response surface method and multiobjective particle swarm optimization algorithm are applied to realize a compromise among the three optimization objectives. Finally, the results of the simulation and experiment verify the validity and correctness of the modeling and optimization design.