新型转子结构的三自由度混合磁轴承损耗分析

为减少六极径向-轴向混合磁轴承（radial-axial hybrid magnetic bearing，RAHBM）高速下转子产生的损耗，提出了一种部分叠片的转子结构. 首先，用等效磁路法推导了六极RAHMB的悬浮力数学模型，依据该模型设计磁轴承结构参数，对不同转子叠片深度下的铁损和悬浮力进行仿真分析，选择叠片深度最优值；然后，在有限元仿真软件中设定转子转速为50000 r/min，向六极RAHMB分别施加径向和轴向最大控制电流，分析磁轴承产生最大承载力情况下实心转子与部分叠片转子的损耗；最后，对部分叠片转子在正弦扰动电流下的涡流损耗和磁滞损耗进行计算和仿真. 研究结果表明:在产生最大承载力条件下，部分叠片转子结构能够将损耗降低69.7%，虽然轴向承载力减小了14.7%，但仍能够满足设计要求；部分叠片转子可将正弦扰动电流下铁损降低55.4%. 

Core Loss Analysis of Three Degree-of-Freedom Hybrid Magnetic Bearing with Novel Rotor Structure

To reduce the core loss of six-pole RAHMB (radial-axial hybrid magnetic bearing) at high rotation speeds, a novel partially laminated rotor is proposed. Firstly, the suspension force model of six-pole RAHMB is built by using equivalent magnetic circuit method. The structure parameters of six-pole RAHMB are designed according to the mathematical model of suspension force. The core loss and suspension force under different depths of lamination part are analyzed to select the optimal depth value. Then, in the finite element analysis, the rotation speed of rotor is set to be 50000 r/min, and the maximum radial and axial control currents are injected to six-pole RAHMB respectively to analyze the core losses of the solid rotor and partially laminated rotor when the magnetic bearing generates maximum suspension force. Finally, the eddy current loss and hysteresis loss of laminated rotors are simulated and calculated under sinusoidal disturbance current. The results show that the partially laminated rotor can reduce the core loss by 69.7% while producing the maximum bearing capacity; although the axial bearing capacity is reduced by 14.7%, it still meets the design requirement; besides, the core loss is reduced by 55.4% under sinusoidal disturbance current.