逆变器驱动式六极径向-轴向混合磁轴承结构原理及性能分析

Inverter-fed three-pole radial-axial hybrid magnetic bearings and their improved sturcture

针对三极磁轴承结构不对称及其三相电流之和必须为零的限制所导致的悬浮力和控制电流之间存在非线性、强耦合的问题,本文提出了在空间上对称分布的六极磁轴承,并对其结构原理及性能展开研究。首先,介绍了逆变器驱动式六极径向-轴向混合磁轴承的结构和工作原理,采用等效磁路法推导出数学模型;其次,通过理论分析和有限元仿真分别得出三极结构与六极结构的力-电流特性、最大承载力,并对结果进行对比分析;最后,实验研究表明:相比于三极结构,六极结构的悬浮力和控制电流之间的非线性得到了明显的改善,最大承载力提高16%,验证了理论分析的正确性。

Owing to the asymmetry of the inverter-fed three-pole magnetic bearing and the condition that the sum of the three-phase current must be zero,the relationship between the radial suspension force and the control current is nonlinear and strong coupling.In order to solve this problem,a spatial symmetric six-pole structure is proposed in this paper.Firstly,the structure and working principle of the inverter-fed six-pole radial-axial hybrid magnetic bearing were introduced.The mathematical model was derived by the equivalent magnetic circuit method.Secondly,through theoretical analysis and 3-D FEM analysis,the force-current characteristics and maximum carrying capacity of the three-pole structure and the six-pole structure were obtained,respectively,and the results were analyzed and compared.Finally,the experimental results show that compared with the three-pole structure,the nonlinear between the suspension force and the control current of the six-pole structure is obviously improved,and the maximum bearing capacity of the six-structure is increased by 16%,which verifies the correctness of the theoretical analysis.