高集成度6/4极锥形无轴承开关磁阻电机五自由度磁悬浮系统的基础研究

The Five-Degree Of Freedom (5-DOF) magnetic levitation system based on 6/4 conical bearingless switched reluctance motor (CBSRM) integrates magnetic bearing technology with switched reluctance motor (SRM), which has high integration density because there are only two CBSRMs in the system. Its simple and compact structure increases the rotor critical speed and system power density. Therefore, this novel 5-DOF magnetic levitation system owns good competition in high speed application such as more-electric aircraft, ships, flywheel energy storage, etc. Aiming at increasing the system integration and power densities, this project focuses on the principle, control method, power converters and experimental platforms. The main contents are summarized as follows. Firstly, in order to facilitate the control of levitation and torque, the electromagnetic characteristics and mathematical models of CBSRM are studied, and the machine design is also optimized. Secondly, the principle and control strategy of CBSRM are investigated to improve the system performance. Thirdly, in order to further improve the motor high-speed capability and increase the integration density of power control system, different converter topologies are studied for CBSRM. Finally, the control scheme of the axial levitation and 5-DOF nonlinear control method are explored for the 5-DOF magnetic levitation system so that the performance on 5-DOF magnetic levitation can be further improved. Moreover, the 5-DOF magnetic levitation prototype consisting of two CBSRMs is established to achieve the integrated design of system, and then obtain the characteristics of levitation force and output torque.

由两台6/4极锥形无轴承开关磁阻电机（CBSRM）构成的五自由度磁悬浮系统集电机与磁轴承技术于一体，结构简单、紧凑，具有很高的集成度，有望提高转子的临界转速和系统的功率密度，从而进一步强化其在多电飞机、舰船、飞轮储能等高速领域的应用基础。本项目拟基于6/4极CBSRM开展五自由度磁悬浮系统的研究，着力提高五自由度磁悬浮系统的功能集成度。具体内容包括：研究CBSRM电磁特性和本体结构优化方法，建立悬浮力和转矩的数学模型，为电机控制奠定理论基础；研究CBSRM运行机理及其悬浮力和转矩协调控制方法，以提高系统运行性能；以充分发挥电机的高速适应性和提高功率系统集成度为目标，探索适用于CBSRM的功率变换器拓扑；研究磁悬浮系统轴向位移协调控制策略和五自由度非线性控制方法，全面提高五自由度磁悬浮系统的悬浮控制精度。研制实验样机，探索和实现该系统的集成化设计，获得悬浮力和转矩的输出特性分布规律。

本课题主要研究基于锥形无轴承电机的磁悬浮系统关键技术，旨在从结构上提高磁悬浮系统的集成度、从控制上提升磁悬浮系统的运行性能，从而进一步强化无轴承开关磁阻电机在多电飞机、舰船和飞轮储能等高速、高功率密度驱动领域的应用基础。主要研究内容包括：探索无轴承开关磁阻电机的数学建模规律，尤其是锥形无轴承电机的径向力和轴向力的建模方法，提出了基于旋转坐标系法的数学建模方法，为无轴承电机磁悬浮系统的数学建模提供了新的解决思路；研究了五自由度磁悬浮系统中轴向力的主动控制方法，提出了无轴承电机磁悬浮系统中多自由度协调控制方法，为解决五自由度磁悬浮系统中的悬浮和旋转的耦合控制问题提供了研究思路；基于“直接控制”思想，提出了无轴承电机直接转矩和直接悬浮力控制方法，能够有效抑制转矩脉动和悬浮力波动；进一步地，结合直接转矩滞环控制思路，提出了无需磁链滞环控制的直接瞬时转矩和直接悬浮力控制方法，对无轴承电机的悬浮和旋转控制策略进行优化，有效降低了电机悬浮控制时产生的负转矩，在降低电流有效值的同时减少了开关次数，为提高无轴承电机的转矩电流比奠定了基础；研制了多套无轴承电机系统硬、软件平台，进一步完善无轴承电机的设计理论和应用实践方法，为推动无轴承电机的实用化积累了丰富的实践经验。