Design and Control of Novel High-speed Bearingless Motors

无轴承电机是一种电机，其中转子被磁悬浮并由单个定子旋转。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，迄今为止，无轴承电机仅应用于所需速度和功率适中的利基应用，例如血泵。高速无轴承电机技术仍处于实验室水平，主要是因为它涉及多学科设计和控制挑战。该研究计划的长期目标是建立高速（？）100 krpm）和大功率（P> 10 kW）无轴承电机技术，用于工业应用。在麻省理工学院攻读博士学位期间，我开发了用于低成本一次性血泵叶轮的无磁转子无轴承电机。与传统的永磁转子电机相比，我们的设计具有极高的速度操作，由于提高转子强度的潜力。此外，无磁体转子适用于高温工业机械，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结构来推动中等功率（P~1 kW）无轴承电机的速度极限。我们的主要方法包括：1）设计和优化无磁转子无轴承电机; 2）开发用于多相绕组高速电流控制的电力电子系统; 3）建立用于高速转子稳定的多变量估计和控制方法。该研究计划将培养五名HQP，包括两名博士和三名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，转子动力学，测量和仪器仪表，电力电子和控制。电动机在工业中被用作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，这些都是能源和环境部门不可或缺的。因此，即使电动机的性能略有改善，也会对节能产生很大影响。例如，由于接触式轴承的润滑剂渗入制冷剂，HVAC系统中传统冷却泵的效率下降超过10%。无轴承电机可以通过消除对机械轴承和润滑剂的需要来节省这种损失。除了社会经济影响外，拟议的研究计划还将通过丰富我们对精密机电系统设计和控制的知识来产生智力影响。

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.