【作者】 杨益飞；

【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】 磁悬浮轴承(简称磁轴承)具有无机械接触、无磨损、无需润滑、无污染、高精度、寿命长等优点,在洁净空间、压缩机和卫星等多种需要无接触支承的场合起到了很重要的作用。本课题组研究了一种新型的交流主动磁轴承,与传统的直流磁轴承相比,它具有结构紧凑、成本低、便于驱动与控制等优点。论文设计了新型结构的五自由度交流主动磁轴承支承的电主轴系统,建立了状态方程,并以降温为目标,运用有限元方法对磁轴承进行参数优化设计,得出了满意的设计方案。在此基础上,采用改进H∞输出反馈控制算法抑制磁轴承的径向和轴向扰动,最后构建了五自由度交流主动磁轴承支承的电主轴数字控制系统,并对电主轴的五自由度悬浮支承技术进行了基础理论和PID参数鲁棒稳定域典型实验研究。论文工作是在国家自然科学基金(60974053)和江苏省自然科学基金(BK2012707)等资助下开展的。本文主要研究工作及取得的成果如下：1.设计了用于高速电主轴一端悬浮支承的三相交流主动磁轴承,采用等效磁路法对磁轴承的磁路进行了计算,导出了悬浮力数学模型。依据数学模型及性能要求,给出了相关设计参数的方法,并研究了其控制策略。2.提出了径向主动磁轴承温度场参数化有限元分析方法。建立定子绕组线圈的等效导热模型,降低了计算难度。解决了定转子之间的气隙热交换问题。给出了定子线圈绕组传热途径,建立了等效热路图模型,合理处理了温升对线圈绕组阻值的影响。计算了定子磁极绕组的等效体积,在此基础上得出了准确的线圈铜耗的生热率。对温度场和热损耗进行分析,给出了径向主动磁轴承三维全域温度场模型。采用三因素三水平的正交试验设计方法,在满足静态悬浮力和最大悬浮力性能要求的前提下,分析并研究了交流主动磁轴承的结构参数优化设计方法,给出了关于温度的最佳参数水平组合。仿真结果证明了所选用模型的正确性和所采用方法的实用性和有效性。3.提出一种抑制交流主动磁轴承径向和轴向扰动的最优H∞输出反馈控制算法。在本文中,分别采用了最优输出反馈控制和最优H∞输出反馈控制改善磁轴承的径向和轴向位移调节。通过求解Riccati方程得到满足最小性能指标的输出反馈控制增益矩阵,并将该增益矩阵反馈到系统中,用来改善系统性能。上述两种控制方法可以有效调节磁轴承的径向和轴向位移输出,并通过使用Matlab和Simulink工具箱对其进行了验证。仿真结果表明文中提出的最优H∞输出反馈控制在有扰动存在情况下,其效果优于最优输出反馈控制。4.提出仅依靠频率响应确定轴向磁轴承的PID参数鲁棒稳定域的方法。首先根据小增益定理得到闭环系统的鲁棒稳定性条件,由此推导出加性不确定性的内部稳定H∞指标,再由边界穿越定理和D-分割技术,推导了满足H∞指标的PID控制器的鲁棒参数稳定域边界的解析表达式。在稳定域中选择PID参数,可以使得系统稳定并满足鲁棒性能约束条件。该方法降低了轴向磁轴承PID控制器参数稳定域设计的难度,对时滞系统PID参数调节具有良好的鲁棒性和可操作性。仿真实验证明了本章方法的有效性。5.设计了基于数字信号处理器TMS320F2812DSP的五自由度交流主动磁轴承数字控制系统软、硬件方案,给出了软件总体流程图以及各中断子流程图,进行了局部实验,以实例对所第五章中提出算法的有效性进行了验证,实现了交流主动磁轴承稳定悬浮。提出了详细的实验及测试方案,为进一步开展各项参数调试与功能测试奠定了基础。更多还原

【Abstract】 For the demands of high speed and high accuracy, the use of active magnetic bearings (AMBs) plays a key role in various situations such as clean room, compressor, satellite and so on, due to their contactless nature, no lubricated, no pollution, high-precision, long service life, and etc.. A new-style AC active magnetic bearing is proposed in the dissertation. Compared with the traditional DC magnetic bearing, the AC AMB has many advantages, such as compact configuration, low cost, convenient driving and control, and so on. A new-style construction of electric spindle supported by five degrees of freedom AC active magnetic bearings is designed in this paper, state equation was established. Aim for lower temperatures, the optimum design for structural parameters of active magnetic bearing was discussed by using finite element method, and we get complete design parameters. On this basis, we adopted the improved H∞output feedback control method to suppress the radial and axial directions position perturbation of AMB systems effectively. The digital control system of electric spindle supported by five degrees of freedom AC AMBs is developed. The basic theory and proportional integral derivation (PID) robustness stability region tests of electric spindle system’s five degrees of freedom suspension supporting technology are researched. The dissertation research is supported by National Natural Science Foundation of China project (60974053) and Jiangsu Province Natural Science Fund (BK2012707). The main contents of the dissertation and the achievements are as follows:1. A three-phase AC active magnetic bearing was designed which was used in high speed electric spindle’s suspension, respectively. The flux path of this magnetic bearing was calculated by using equivalent magnetic circuit, and the mathematical models of suspension forces were deduced respectively. Then based on the mathematics models, the relatively design parameters were given. The control strategy of three-phase AC active magnetic bearing was also proposed, respectively.2. Radial active magnetic bearing’s thermal field parametric finite element method is proposed. A model of equivalent thermal conductivity of the stator coil winding is set up, by means of which the difficulty in calculating the active magnetic bearing thermal field is reduced to some extent. The air gap heat exchange between the stator and rotor is worked out. By means of setting up the equivalent thermal circuit, the way to heat dissipation of the stator coil winding is given and temperature rise influence on coil winding is legitimately treated. On the basis of the equivalent volume of the stator is calculated, heat generation rate of winding copper loss is precisely calculated. According to the electromagnetic field design parameters, the active magnetic bearing’s temperature field and thermal loss is further analyzed, so, thermal Field numerical calculation of the radial active magnetic bearing is given, which could help optimum design of active magnetic bearing in the future. Based on the orthogonal design method which has three three levels factors, a parameters optimum design method was researched in this thesis. On the premise that the product design could satisfy the demands of maximum static suspension forces and maximum suspension forces, an optimization design method about active magnetic bearing was studied and the best combination of the parameters about temperature are given. The simulation proved the validity of the model and the practicability of the method used in the research.3. We propose the improved H∞output feedback control method for suppressing the radial and axial directions position perturbation of AC AMB systems. In this research, two other control options for high speed machine were designed based on the optimal output feedback and the improved H∞output feedback control methods to improve the radical and axial position regulation of AMB. The output feedback control gain matrix with the minimum performance index is obtained by solving the Riccati equation and fed back to the system in order to achieve the system’s performance. The above designed controllers can efficiently regulate the radial and axial directions position deviation of for AMB systems. Simulations for the two control methods were carried out using Matlab and Simulink for AMB system models. Results show that the improved H∞output feedback controller has a better position deviation control performance over the optimal output feedback under condition of decreasing the disturbance of reaction.4. A method is proposed for finding all PID controllers that satisfy a robust performance constraint for a given transfer function of any order with time-delay by using the frequency response. The H-infinity index of additive weight uncertainty on the basis of robustness stability condition of closed loop system is first get by small gain theorem. Then, Based on the boundary crossing theorem, the parameter boundaries with the expected decay ratio index of PID controller are derived. The system can be stabilized and robustly meet the performance requirements by choosing PID controllers parameter in the stability region. The proposed method avoids the complexity of stability regions of PID parameters, the closed-loop system has strong robustness for any order time-delay system with no accurate model. The simulation results demonstrate the validity of this method. 5. Finally, the five degrees of freedom AC AMBs system’s software and hardware circuits based on digital signal processor TMS320F2812DSP have been designed, the flow charts for main program and interrupt programs have been listed too. Local experiment is done. The verification on the effectiveness of the being proposed algorithm in chapter five was put forward by a living example to realize the AC active magnetic bearing stably suspension. The detailed experimental and testing procedures have been proposed, which establishes a good foundation for the next parameters debugging and function test.更多还原