Recent efforts to improve the performance of bearingless motors have focused on “combined winding” machine designs that use the same coils for torque and suspension force production. While combined winding designs have been successful in increasing the machine performance, they add substantial cost and complexity to the power electronics required for the bearingless drive system. This article presents a bearingless drive concept, which eliminates the additional power electronic hardware requirements for a parallel combined winding design. The resulting drive requires the same hardware components as a traditional, separated winding bearingless motor. The article proposes and explains the design and theory of operation, proposes a simple control implementation, and presents initial validation via simulation results. The theory and design presented are valid for both conventional $p\pm 1$ bearingless motor designs (i.e., bearingless permanent magnet designs) as well as $p_s=1$ bearingless motor designs (i.e., bearingless ac homopolar designs). Experimental results are provided that validate the proposed concept and demonstrate stable levitation of a bearingless motor.

中文翻译：

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并联组合绕组无轴承电机浮动电容悬浮逆变器

最近提高无轴承电机性能的努力集中在“组合绕组”机器设计上，该设计使用相同的线圈产生扭矩和悬浮力。虽然组合绕组设计在提高机器性能方面取得了成功，但它们为无轴承驱动系统所需的电力电子设备增加了大量成本和复杂性。本文介绍了一种无轴承驱动概念，它消除了并联组合绕组设计的额外电力电子硬件要求。由此产生的驱动器需要与传统的分离绕组无轴承电机相同的硬件组件。本文提出并解释了设计和操作理论，提出了一个简单的控制实现，并通过仿真结果进行了初步验证。$p\pm 1$ 无轴承电机设计（即无轴承永磁体设计）以及 $p_s=1$无轴承电机设计（即无轴承交流单极设计）。提供的实验结果验证了所提出的概念并证明了无轴承电机的稳定悬浮。