Design and Control of Novel High-speed Bearingless Motors

无轴承电机是一种电机，转子是磁悬浮的，由单个定子旋转。这些电机可以消除机械轴承的问题，如摩擦、磨损、润滑和散热，因此有利于高速工业应用。然而，到目前为止，无轴承电机仅应用于小众应用，例如血泵，其中所需的速度和功率适中。高速无轴承电机技术目前仍处于实验室水平，主要是因为它涉及多学科的设计和控制挑战。这项研究计划的长期目标是建立高速(？bb> 100krpm)和大功率（bb> 10kw）无轴承电机技术用于工业应用。在MIT攻读博士期间，我为低成本的一次性血泵叶轮开发了无磁转子无轴承电机。与传统的永磁转子电机相比，由于转子强度的提高，我们的设计具有极高的高速运行潜力。此外，无磁转子有利于高温工业机械，如蒸汽和燃气轮机。在这5年的发现资助期内，我的团队将通过利用无磁转子拓扑来推动中等功率（P~1 kW）无轴承电机的速度限制。我们的主要研究方向包括：1)设计和优化无磁转子无轴承电机；2)开发多相绕组高速电流控制的电力电子系统；3)建立高速转子稳定的多变量估计和控制方法。该研究项目将培养5名HQP，其中包括2名博士和3名MASc学生。我们的机电一体化研究活动将伴随着科学和工程各个学科的创新，如机电建模和仿真，旋转动力学，测量和仪器，电力电子和控制。电动机是工业上主要的机电能量转换装置。它们构成了鼓风机、压缩机和泵的基础，是能源和环境部门不可或缺的产品。因此，即使是电机性能的轻微改进也会对节能产生很大的影响。例如，由于接触式轴承的润滑剂浸入制冷剂中，HVAC系统中传统冷水机泵的效率下降了10%以上。无轴承电机可以通过消除对机械轴承和润滑剂的需求来节省这种损失。除了社会经济影响之外，拟议的研究计划还将通过丰富我们在精密机电系统设计和控制方面的知识而产生智力影响。

Bearingless motors are a type of electric machine where the rotor is magnetically levitated and rotated by a single stator. These motors can eliminate the issues of mechanical bearings, such as friction, wear, lubrication, and heat dissipation, and therefore are favorable for high-speed industrial applications. However, bearingless motors have been so far applied only to niche applications, e.g. blood pumps, where the required speed and power are moderate. High-speed bearingless motor technology is still at a laboratory level, mainly because it involves multidisciplinary design and control challenges. The long-term goal of this research program is to establish high-speed (?>100 krpm) and high-power (P>10 kW) bearingless motor technology for industrial applications. During my doctoral study at MIT, I developed bearingless motors with magnet-free rotors for low-cost disposable blood pump impellers. Compared to conventional motors with permanent-magnet rotors, our design has potential for extremely high-speed operations due to the improved rotor strength. Also, the magnet-free rotors are favourable for high-temperature industrial machinery, such as steam and gas turbines. Within this 5-year Discovery Grant period, my group will push the speed limit of medium power (P~1 kW) bearingless motors by leveraging the magnet-free rotor topologies. Our key approaches include: 1) design and optimize bearingless motors with magnet-free rotors; 2) develop power electronics systems for high-speed current control of multiphase winding; and 3) establish multivariable estimation and control methods for high-speed rotor stabilization. The research program will train five HQP, including two PhD and three MASc students. Our mechatronics research activities will accompany innovations across various disciplines in science and engineering, such as electromechanics modeling and simulation, rotordynamics, measurement and instrumentation, power electronics, and control. Electric motors are used as the primary electromechanical energy conversion devices in industry. They form a basis for blowers, compressors, and pumps, which are indispensable to the energy and environment sectors. Therefore, even a slight performance improvement on electric motors can have a large impact in energy saving. For example, the efficiency of conventional chiller pumps in HVAC systems drops by more than 10 % due to the contact-type bearings' lubricants leaching into the refrigerant. Bearingless motors can save such a loss by eliminating the need for mechanical bearings and lubricants. Beyond the socioeconomic impacts, the proposed research program will also make an intellectual impact by enriching our knowledge on the design and control of precision mechatronic systems.