【作者】 杨泽斌；

【导师】 朱熀秋；

【作者基本信息】 江苏大学 ， 电力电子与电力传动， 2013， 博士

【摘要】 无轴承电机突破传统电机保持气隙磁场平衡,仅仅产生电磁转矩的旧框架,利用磁轴承结构和电机定子结构的相似性,通过定子中两套不同极对数绕组磁场的相互作用,破坏传统电机气隙磁场的对称性,产生电磁转矩和径向力,能同时实现转子悬浮和旋转功能。无轴承异步电机(Bearingless Induction Motor, BIM)集异步电机(结构简单、齿槽脉动转矩低、易于弱磁控制、可靠性高等)和磁轴承(无磨损、无接触、无噪声、无需润滑和寿命长等)优点和功能于一体,能实现高速及超高速、真空、洁净、腐蚀等特殊环境的无轴承支承运行,能推动装备向高、精、尖方向发展,目前已经成为特种驱动/传动领域的研究热点之一本文在国家自然科学基金项目(61104016、60974053)和江苏省高校自然科学基金项目(11KJB510002)的资助下,为了解决BIM应用于高速驱动/传动领域中遇到的技术难题,并以实现BIM高速度、高可靠、低成本运行为目标,对其可实现结构、数学模型、电磁分析、多变量非线性解耦控制、无速度传感器运行、数字控制系统实现等方面进行了重点研究,主要研究工作及取得的成果如下：1.在介绍传统电机中存在的麦克斯韦力和洛仑兹力基础上,阐述了BIM径向力产生机理；基于电磁场理论,分析了BIM转子所受的洛伦兹力,以及转子不偏心和偏心两种情况下转子所受的麦克斯韦力,并进行了数学推导；在分析比较不同BIM可实现结构一般形式的基础上,设计了实验用BIM系统机械结构。2.详细推导BIM数学模型,并提出采用有限元瞬态法,通过详细分析不同情况下BIM电磁场分布和径向力计算值,验证了BIM悬浮机理以及径向力数学模型的正确性和精确度,为BIM进一步的悬浮解耦控制奠定了基础。3.针对BIM多变量、非线性、强耦合的特点,分别以2自由度和5自由度BIM为被控对象,将逆系统与最小二乘支持向量机(LSSVM)目结合,提出了基于LSSVM逆的BIM动态解耦控制方法。建立2自由度BIM状态方程,证明其可逆,通过LSSVM逼近原系统的逆模型,并将其串接于原系统之前,将2自由度BIM线性化解耦成位移、转速和磁链子系统,并设计复合控制器,仿真结果表明采用该策略系统具有优良的解耦效果和动态特性。鉴于LSSVM逆方法的优越性,充分利用LSSVM在有限数据样本下对高维非线性函数的回归能力,辨识5自由度BIM逆模型,并利用粒子群算法优化LSSVM参数,以提高其对逆模型的拟合和预测精度。将LSSVM逆与原系统串联得到伪线性系统,并运用线性系统理论设计闭环控制器,仿真结果表明该方法同样实现了5自由度BIM转速、磁链、径向位移和轴向位移之间的高精度非线性动态解耦控制。4.针对BIM无速度传感器运行的需要,提出一种基于LSSVM左逆的转速软测量策略。根据BIM数学模型参量的内在约束关系,建立转速与转矩绕组电流关系的转速子系统,并证明其可逆。采用LSSVM构造转速子系统左逆软测量模型,并将其与原转速子系统相串联,复现该子系统的转速输入,从而实现了对转子速度的有效观测。应用该策略构建BIM无速度传感器矢量控制系统仿真平台,仿真结果表明该策略能在BIM全速范围内准确观测出转子速度,实现BIM在无速度传感器方式下的稳定悬浮运行。5.针对BIM控制系统采用电流调节型脉宽调制(CRPWM)逆变器实现转速和径向位移单闭环控制的不足,提出了基于空间电压矢量脉宽调制(SVPWM)算法的BIM矢量控制策略,对BIM转矩绕组和径向力绕组分别增加了电流内环,改善了系统的控制性能。构建了以TMS320F2812数字信号处理器(DSP)为核心的BIM数字控制系统硬件和软件系统,并在此数字控制实验平台上进行了BIM动态悬浮运行的实验研究,最后给出了实验波形并分析了实验结果。实验结果表明所设计的数字控制系统能实现BIM的稳定悬浮运行,而且具有优良的静、动态特性。更多还原

【Abstract】 A bearingless motor is a new type of motor which breaks through the traditional motor theory of keeping the balance of air-gap magnetic field to produce electromagnetic torque. Using the structure similarity between the magnetic bearing and motor’stator, the bearingless motor is embedded in two sets of different pole-pair windings to destroy the symmetry of air-gap magnetic field, and thus to produce electromagnetic torque and radial force so as to realize the functions of rotor suspension and rotation.Compared with other types of bearingless motors, the bearingless induction motor.(BIM), which not only contains the advantages of conventional induction motor, such as simple structure, low pulsating torque andeasy flux-weakening control, but also the virtues of magnetic bearing, such as no contact, no abrasion, no lubrication, no pollution and long service life, can make it popular in the special drive fields including high and ultra-high speed operation, vacuum, clean and corrosion environment, and promote the development of equipment toward high-grade, high-precision and sophisticated. Furthermore, the BIM has become one of the hot spots in the research fields of bearingless motors presently.Under the susports of the National Natural Science Foundation of China(61104016) and the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (11KJB510002), in order to solve the application of BIM with high speed, high reliability and low cost in driving field, a comparative systematical and deep research of the BIM is made, including mechanical structures, mathematical model, electromagnetic analysis, decoupling control, speed-sensorless operation, and digital control system implementation and so on. The main contents of the dissertation and the achievement are as follows:1. The Maxwell force and Lorentz force in traditional motors are elaborated, and then the producing principle of radial suspension forces in the BIM is introduced. Based on the electromagnetic theory, the analytical expressions of the Lorentz force and Maxwell force with the eccentricity and non-eccentricity in the location of rotor are analysed and deduced. Through analyzing and comparing the performance characteristics of different BIM structures, the experimental mechanical structure system of BIM is designed.2. Based on the principle of virtual displacement, the mathematical models of BIM taking into account the rotor eccentricity are derived in detail, and their accuracy and precision are verified by the transient finite element method. This work lays the foundation for further suspension decoupling control of BIM.3. A novel decoupling control strategy based on least squares support vector machine(LSSVM) inverse are proposed for the2-degree-of-freedom and5-degree-of-freedom BIM, respectively, which are multi-variable, nonlinear and stongly coupled systems. Firstly, according to the reversibility analysis of original system, the inverse model of the2-degree-of-freedom BIM was approximated by LSSVM and connected with the original system to construct pseudo-linear system. The pseudo-linear system is equivalent to two independent linear displacement subsystems, a linear rotor speed subsystem and a linear magnetic flux linkage subsystem. And then the compound controller is designed. The simulation results show that this strategy has excellent decoupling effect and dynamic characteristics. Secondly, In view of the superiority of LSSVM inverse method, the inverse model of5-degree-of-freedom BIM is built using LSSVM which has a good fitting capability to high dimensional nonlinear functions with limited samples. In addition, the particle swarm optimization algorithm is used to optimize parameters of the LSSVM, which can improve the precision of the predictive model, and then the LSSVM inverse model is combined with the original system to constitute the pseudo linear system, and then PID closed-loop regulators are designed to realize the compound control for5-degree-of-freedom BIM. The dynamic decoupling control among the radial and axial displacements, speed and flux linkage are also achieved and the simulation researches verify the effectiveness of the proposed control strategy.4. Aiming at the need of speed sensorless operation for BIM, a novel rotor speed soft-sensing method based on LSSVM left inverse is proposed. Firstly, according to the inherent relationship among the variables of BIM, the speed subsystem consisting of rotor speed and stator currents of the torque winding is established and proved to be invertible. Secondly, the left inverse model was constructed using LSSVM, and then the obtained inverse model is combined with this subsystem, the rotor speed input of the subsystem is gained, i.e., the rotor speed is observed effectively. Finally, a vector control simulation platform of BIM is established to evaluate the proposed method. The simulation results demonstrates the proposed LSSVM left inverse method can accurately identify the speed parameter in a full speed operation region with good dynamic and static performance.5. According to the deficiency of single closed-loop control of the speed and radial displacement with the current regulated pulse width modulated (CRPWM) inverter in BIM control system, the vector control strategy based on the space vector pulse width modulation (SVPWM) is proposed. In order to improve the performance of the control system,the current closed-loops are adopted for both torque winding control and suspension force winding control. The hardware and software of digital control system are built with the core of digital signal processor TMS320F2812. And then, the experimental studies are carried out, and the experimental results verify that the stable suspension and operation of the BIM can be perfectly realized through the SVPWM control strategy.更多还原