【作者】 张颖；

【导师】 陈幼平； 周祖德； 艾武；

【作者基本信息】 华中科技大学 ， 机械电子工程， 2008， 博士

【摘要】 永磁同步直线电机将电能直接转换为直线运动,取消了传统的从旋转电机到工作台之间的一切中间传动环节,进给系统可以直接驱动负载,具有高速、高精的特性,因此直线电机正在成为高档数控机床的主要功能部件,在高速高精数控系统、IC制芯和封装设备、光刻机等众多应用场合具有广阔的应用前景。然而,直线电机存在由端部效应和齿槽效应引起的磁阻力扰动、负载扰动、系统参数摄动等因素形成的推力波动,直接影响高精度数控加工系统的定位精度和低速时的速度平稳性,成为影响直线电机广泛应用于工业实践的重要原因。本文以削弱推力波动对永磁同步直线电机性能的影响为核心问题,对推力波动产生的因素和计算方法进行了分析,提出了磁阻力的结构优化方式和推力波动的控制策略补偿方案,并进行了相关的实验研究。首先从直线电机设计角度进行研究,针对推力波动的主要因素磁阻力,运用等效磁化电流法和Schwarz-Christoffel变换建立了直线电机电磁场分析的模型,利用麦克斯韦张量法对直线电机的磁阻力进行分析,证明磁阻力可以依据其产生原因分解成由端部效应产生的端部力和由齿槽效应所产生的齿槽力,并根据这一分析结果分别建立相应的有限元分析模型,对端部力和齿槽力分别进行数值计算,提出了降低端部力和齿槽力的结构优化设计方法。其次,综合运用电机控制理论和计算机仿真技术,分别对永磁同步直线电机的矢量控制原理、运动力学模型以及电压空间矢量脉宽调制技术进行分析,搭建了永磁同步直线电机伺服控制系统的数学模型。针对推力波动对于直线电机的速度控制精度和平稳性影响较大的问题,设计了速度环滑模控制器。针对滑模控制器所引入的抖振现象,设计了扰动观测器,对系统扰动进行补偿。同时,采用模糊控制策略设计了模糊滑模控制器,对滑模控制器中的切换控制幅值进行实时地调整,实现了在不影响系统鲁棒性和快速跟踪性能的前提下,减小系统抖振的控制目的。在上述理论分析的基础上,详细地介绍了以DSP芯片为核心的永磁同步直线电机伺服控制系统的软硬件设计和实现,并对所提出的结构优化措施和控制优化策略进行了实验验证。更多还原

【Abstract】 The electrical energy can be transferred into linear motion by permanent magnetic synchronous linear motors (PMSLMs), and all intermediate transmission mechanism can be canceled. Therefore, the feeding system can drive load directly, and realize manufacturing procedure with high speed and high precision. Consequently, PMSLM is becoming the principal function device of super-quality NC machines, and has extensive application perspectives in NC systems with high speed and high precision,IC manufacture and packing devices, lithographic tools,and so on. However, in the PMSLMs, there exists thrust ripple caused by the load disturbance, the detent force generated by end-effect and slot-effect, and the perturbation of system parameters, which has negative effect on the positioning accuracy and the steadiness at low speed, and then becomes one of significant causes interfering with the widely use of the PMSLMs in industrial practice. This paper focused on how to weaken the negative effect of thrust ripple on the performance of the PMSLMs, and analyzed the occurrence reasons and the calculation methods of thrust ripple, and proposed the corresponding constructive design methods to reduce detent force and the control strategy to restraint thrust fipple, and performed experiments to verify the validity of the proposed methods above.Firstly, the detent force that is the main reason of thrust ripple was analyzed by the motor design methods. The analysis model of the magnetic field in the PMSLM was built by means of equivalent magnetizing current and Schwarz-Christoffel transformation, and the detent force was analyzed by Maxwell stress. The analysis results showed that the detent force could be divided into the end force caused by end-effect and the cogging force caused by slot-effect, and then the finite element models were set up to calculate the end force and the cogging force respectively, as the result, the corresponding constructive design methods were proposed.Secondly, the vector control theory,the kinematics model and the sinusoidal space vector Pulse-Width-Modulation (SVPWM) control technology were analyzed dividually, and then the mathematic simulation model of the servo system of PMSLM was built. Since the thrust ripple has great influence on the precision and steadiness of the velocity control, the sliding-mode control device of speed loop was designed. In order to reduce the chattering of the sliding-mode control, the disturbance observer was designed to estimate the disturbance of the servo system and the estimation was fed back to the output current of the sliding-mode control. Furthermore, the fuzzy control strategy was introduced to modify the amplitude of the switching control at real time, in order that the chattering of the control system was weakened, and at the same time, the robustness and the fast tracking performance were maintained.On the basis of the theory study above, the design and the realization of the software and hardware of the servo system of PMSLM based on the DSP was described in detail, and the experiments were made to verify the effectiveness of the proposed constructive design methods and control algorithms.更多还原