【作者】 娄杰；

【导师】 李庆民；

【作者基本信息】 山东大学 ， 高电压与绝缘技术， 2009， 博士

【摘要】 支撑智能电网发展的重要技术基础之一是高压电器的智能化,其中断路器智能操作的实现,对电磁机构的快速性与可控性提出了更高要求,这有赖于新型电磁机构的拓扑设计和参数优化研究。就目前国内外研究现状而言,能综合快速性和可控性两个层面,对电磁机构的拓扑设计与优化分析方法做出系统研究的工作并不多见。本文从电磁机构的拓扑入手,研究四种新型电磁机构的拓扑形式,提出了较为系统的拓扑设计与优化分析方法,为新型电磁机构的发展奠定了理论与技术基础。首先针对盘状推斥型快速电磁机构进行理论分析,基于单匝线圈间的相互作用关系推导出该型电磁机构的动态分析模型,并提出一种基于时间和位移双层循环的离散迭代算法,该算法可用于推斥型盘状电磁机构的仿真分析与综合优化设计。但就实现机构的实时可控性而言,这些数学模型与算法还显得相对复杂。鉴于旋转电机已具备较为成熟的控制方法,本文提出了基于永磁电动机控制的断路器操动机构方案。通过分析旋转运动与直线运动的转换关系,并综合PID与单神经元控制等方法,建立了该机构运动特性的速度跟踪控制策略,为实现机构的柔性可控提供了方法基础。但由于电动机的电磁惯性以及传动环节的机械惯性较大,并不利于实现机构的快速性。为综合利用上述两种电磁机构的优点,本文提出了一种兼顾运动快速性与可控性的电磁机构—音圈电机式快速电磁机构。因采用相对磁导率很小的永磁体使得回路电感显著减小,而利用对称的差动补偿结构则可保持运动过程中的等效电感基本不变,从而简化机构的分析模型。基于电磁学和机械动力学分析,采用等效受控电压源的形式来描述机构电磁与机械特性的复杂耦合关系,为解决电磁机构的解耦分析与控制问题提供了一种新思路。利用PSIM软件建立了基于PWM的速度跟踪控制仿真模型,仿真结果表明,利用电力电子器件和PWM控制方式基本可实现机构分合闸操作的无碰撞反弹,为断路器最佳运动曲线的跟踪控制奠定了方法基础。不过,因存在铁芯、永磁体等性能易受外界较大磁场影响的材料,增加了机构的非线性特征,使控制的准确性在较大电流时难以保证。为克服机构中使用非线性磁材料的缺点,并同时考虑可控性对机构拓扑结构的设计要求,本文提出研究一种反绕嵌套螺线管式新型电磁机构。该机构的固定部件和可动部件均由线圈构成,无铁芯亦无永磁。通过分析线圈磁场横向分量的分布规律,提出相互作用系数的概念以描述机构的耦合模型。在拓扑结构确定的情况下,该作用系数为常数,即电磁力与电流的平方成正比,从而大大简化机构的数学分析模型,为实现机构的可控性奠定基础。研制了该电磁机构的物理样机,并开展了仿真和实验研究。因受拓扑结构和分析方法多样性的限制,对传统电磁机构性能的评价多采用静态评价指标,缺乏针对机构动态特性的评价参数。本文以电磁学方程为基础,通过分析电磁力与控制电流的关系而提出电磁力灵敏度分析系数,以定量评价电流对电磁力影响程度的变化和电磁机构运动过程的可控性。从使用材料、拓扑结构以及电磁力灵敏度等方面,对三种电磁机构的动态性能进行了比较,指出具有较大数值且为恒定灵敏度系数的电磁机构拓扑,在快速性和可控性方面具有发展前景。本文还详细研究了推斥型盘状电磁机构和反绕嵌套螺线管式电磁机构的相互联系,指出二者在拓扑关系上分别是由单匝线圈沿径向和轴向拓展形成的空间结构,前者灵敏度系数的最大值约为后者的两倍,这为电磁机构的拓扑研究提供了新的方法与理论基础。更多还原

【Abstract】 One of the key technical foundations of developing smart grid is intelligentized high voltage apparatus, among which the intelligent operation of circuit breakers is mounting more and more urgent demands for preferable speediness and controllability of the electromagnetic mechanisms, and this relies much on topology design and optimization method of novel electromagnetic mechanisms. As regards the state-of-the-art development all over the world, it has rarely been seen systematic research work on topology design and optimization that incorporates both aspects of speediness and controllability of the electromagnetic mechanisms. Starting with topology design, this dissertation concentrates on four novel type electromagnetic mechanisms, and comprehensive methodology is presented to realise topology design and optimal analysis, which establishes both theoretical and technological basis for developing novel electromagnetic mechanisms.Theoretical analysis is firstly done regarding the disc-type repulsive fast mechanism, and a dynamic model is deduced based on the coupling interaction between single-turn coils, further, a discrete iterative algorithm is proposed based on double-layer iteration of time and displacement, which can be utilised in the simulation analysis and integrated optimization of the disc-type repulsive mechanism. But for instantaneous controllability of the electromagnetic mechanism, these mathematical models and algorithms are still relatively complicated in practice.Many mature control strategies being available for nowadays rotating motors, a permanent magnet motor based control scheme is put forward for possible operation mechanism of circuit breakers. With analysis on the correlation between rotating angle and line displacement, also with integration of PID and single-neutron control methodologies, a control strategy for speed tracking of the mechanism’s moving process is presented, which provides referential method for realising flexible controllability of the mechanism. However, due to relatively large electromagnetic inertia of the motor and mechanical inertia of the drive element, it is to some extent difficult to achieve speediness of the mechanism.In order to incorporate the advantages of both electromagnetic mechanisms described above, a new mechanism, namely motor coil based repulsive electromagnetic mechanism, is proposed with a view to achieving both speediness and controllability. Here, utilization of permanent magnet with small relative permeability lowers the loop circuit inductance, and adoption of the symmetrical and differential compensation structure maintains a roughly invariable equivalent inductance during the moving process of the mechanism, which gives a preferably simplified analysis model. Based on both electromagnetics and mechanical dynamics, an equivalent controlled voltage source is used to present the complicated coupling relationship between the electromagnetic and mechanical characteristics of the mechanism, which gives a new route to address the decoupled analysis and control issue of electromagnetic mechanisms. The PSIM software is used to establish a PWM-based simulation model for speed tracking control, and the results demonstrates that, with power electronics devices and PWM control, it is feasible and effective to achieve roughly zero collision bounce of the mechanism during its switching operations, which presents methodologies for speed control to track a given optimal movement curve of circuit breaker mechanisms. However in the meantime, adoption of iron core and permanent magnet within the mechanism increases nonlinear behaviour of the mechanism, which creates difficulty in guaranteeing control accuracy.To counteract the disadvantages of the nonlinear magnetic materials, and also with consideration of the design requirements from controllability being imposed to electromagnetic mechanism topology, a novel reversely wound and nested solenoid type electromagnetic mechanism is proposed for further investigations. The mechanism is composed of both fixed and moving coils, but without any iron core or permanent magnet. With detailed analysis on the transverse component distribution of the coils’ magnetic fields, an interaction coefficient is presented to describe coupling features of the mechanism. Given the mechanism topology, the interaction coefficient is constant, which to great extent will simplify the mathematical model and thereby facilitate controllability of the mechanism. A prototype model of the novel mechanism is designed, further with simulations and experimental studies being carried out.Owing to diversity of the electromagnetic mechanisms in both topologies and analysis methodologies, it is much often to use static indexes to evaluate the performance of traditional electromagnetic mechanisms, with very few evaluation specifications with regards to the dynamic characteristics of electromagnetic mechanisms. Based on the fundamental equations of electromagnetics, this dissertation puts forward a definition of magnetism sensitivity coefficient to quantitatively appraise the varied impacts of driving current on the coulomb forces, and also to evaluate the controllability of a mechanism’s movement. In terms of materials, topologies and magnetism sensitivity, comparative analysis is carried out regarding to three types of electromagnetic mechanisms, which indicates that, a mechanism with large and also invariable magnetism sensitivity coefficient will foresee prospective advantages in both aspects of speediness and controllability. Further, the topological correlation between the disc-type repulsive mechanism and the reversely wound and nested solenoid type mechanism is studied in details, which shows that both are derived topological configuration from the single-turn coil respectively thorough radial and longitudinal extension, and the magnetism sensitivity coefficient of the former roughly doubles that of the latter one. From the topology point of view, this kind of analysis provides a new route being directed to topology study for developing prospective electromagnetic mechanisms.更多还原