串联磁路混合励磁直线涡流制动器的研究

发布时间：2018-08-24 20:11

【摘要】：涡流制动器(Eddy Current Brake,ECB)是一种基于电磁感应定律和洛伦兹力公式产生制动力或制动转矩的电磁装置。与传统的制动装置相比,涡流制动器具有初、次级之间无接触、可靠性高、控制方便、噪声小、维护方便、系统寿命长、对环境不会造成污染等优点。因此,ECB在制动、抑振和传动等工程领域中的应用非常广泛。本文以直线电机测试平台为应用背景,提出一种新型串联磁路混合励磁直线ECB结构方案,针对其精确解析模型、关键技术问题、设计方法和温升特性开展研究工作。此研究工作对于直线电机测试系统的开发和生产都有重大的意义。首先,利用串联磁路混合励磁直线ECB的等效磁路模型,求出了气隙磁密幅值的表达式。针对等效磁路模型只能计算气隙磁密幅值,而不能得出完整的气隙磁密分布的局限性,本文引入了一个由经验公式得到的分段函数,用该分段函数来拟合气隙磁密波形,即通过结合等效磁路模型和经验拟合函数就可以得出混合励磁直线ECB的气隙磁场幅值以及其波形。随后,建立了串联磁路混合励磁直线ECB的分层模型,并用卡特系数考虑了初级铁心开槽的影响。通过求解分层模型中每个区域的控制方程与区域之间的边界条件,推导出了次级导体板中的涡流幅值与分布、涡流损耗、制动力以及法向力的表达式,即建立了完整的串联磁路混合励磁直线ECB的解析模型。为了提高该解析模型的精度以及适用范围,考虑了初、次级铁心饱和对解析模型的影响,并采用二维有限元法验证了其准确性。其次,采用解析法对直线ECB特有的纵向端部效应,以及横向端部效应进行了研究。即采用一维场理论分析了纵向动态端部效应的影响;采用许-克变换分析了横向静态端部效应的影响;采用导体板分区的方法分析了横向动态端部效应的影响。根据理论分析的结果,分别提出了修正以上端部效应的方法,得出串联磁路混合励磁直线ECB修正的解析模型,并且其有效性和准确性分别采用有限元法和实验测试进行了验证。励磁电流和制动力的动态响应作为衡量ECB动态性能优劣的重要指标,对直线电机测试系统的稳定性和安全运行有很大的影响。本文通过有限元法详细分析了励磁电流和制动力的动态响应随各电磁参数的变化趋势以及其原因,为其在直线电机测试平台中的实际应用提供了理论依据。此外,为验证混合励磁结构方案的优点,比较了混合励磁与电励磁涡流制动器的制动力特性,得出相比于电励磁结构制动力密度大,相比于永磁式结构具有可调性的结论。再次,研究了串联磁路混合励磁直线ECB的设计方法。首先根据ECB的实际应用场合提出了其主要设计指标,并分析了其在设计时应遵循的设计原则,提出了相应的设计流程。随后,利用解析模型推导出了串联磁路混合励磁直线ECB的主要尺寸方程的基础上,根据电磁参数对ECB制动力特性的影响,逐步选取了极距、气隙长度、导体板材料及尺寸、永磁体尺寸、绕组参数和齿槽尺寸等电磁参数,完成了串联磁路混合励磁直线ECB的设计。研制了一台串联磁路混合励磁直线ECB样机,并搭建制动力测试平台,测试了其制动性能随速度和励磁电流的变化曲线。最后,研究了串联磁路混合励磁直线ECB的温度场特性。利用三维流体场模型计算了串联磁路混合励磁直线ECB的周围空气流场分布,并根据该空气流场分布以及无量纲分析法计算了ECB的各散热面的对流传热系数以及对流热阻。在此基础上计算各组件的传导热阻、热源和热容,建立了完整的热网络模型。利用三维温度场有限元模型计算了串联磁路混合励磁直线ECB的温度随着时间的变化,以验证热网络模型的准确性。针对串联磁路混合励磁直线ECB样机,测试其静态、动态温升特性,验证了热网络模型以及有限元模型的准确性和有效性。
[Abstract]:Eddy Current Brake (ECB) is an electromagnetic device based on electromagnetic induction law and Lorentz force formula to generate brake force or brake torque. Compared with traditional brake device, ECB has the advantages of no contact between the primary and secondary, high reliability, convenient control, low noise, easy maintenance, long system life and no environmental impact. Therefore, ECB is widely used in braking, vibration suppression and transmission engineering. In this paper, based on the application of linear motor test platform, a new series magnetic circuit hybrid excitation linear ECB structure scheme is proposed. This work is of great significance to the development and production of linear motor test system. Firstly, the expression of air gap magnetic density amplitude is obtained by using the equivalent magnetic circuit model of hybrid excitation linear ECB with series magnetic circuit. In this paper, a piecewise function derived from the empirical formula is introduced to fit the air-gap magnetic density waveform, that is, the air-gap magnetic field amplitude and its waveform of the hybrid excitation line ECB can be obtained by combining the equivalent magnetic circuit model with the empirical fitting function. By solving the governing equations of each region and the boundary conditions between regions in the layered model, the expressions of eddy current amplitude and distribution, eddy current loss, braking force and normal force in the secondary conductor plate are derived, that is, the complete series magnetic circuit hybrid excitation is established. In order to improve the accuracy and applicability of the analytical model for linear ECB, the influence of initial and secondary core saturation on the analytical model is considered, and its accuracy is verified by two-dimensional finite element method. Secondly, the longitudinal end effect and transverse end effect of linear ECB are studied by analytical method. The influence of longitudinal dynamic end effect is analyzed by the theory of dimensional field, the influence of transverse static end effect is analyzed by Schucker transform, and the influence of transverse dynamic end effect is analyzed by the method of conductor plate partition. The validity and accuracy of the analytical model modified by linear ECB are validated by finite element method and experimental test respectively. The dynamic response of excitation current and braking force, as an important index to evaluate the dynamic performance of ECB, has a great influence on the stability and safe operation of linear motor test system. The variation trend of excitation current and dynamic response of brake force with electromagnetic parameters and its reasons are analyzed in detail, which provides a theoretical basis for its practical application in linear motor test platform. Thirdly, the design method of hybrid excitation linear ECB with series magnetic circuit is studied. Firstly, according to the practical application of ECB, the main design indexes are put forward, and the design principles that should be followed in the design are analyzed. Secondly, the main dimension equation of hybrid excitation linear ECB in series magnetic circuit is deduced by using analytical model. According to the influence of electromagnetic parameters on the braking force characteristics of ECB, the electromagnetic parameters such as pole distance, air gap length, conductor plate material and size, permanent magnet size, winding parameters and cogging size are selected step by step. A prototype of hybrid excitation linear ECB with series magnetic circuit is developed, and a braking force test platform is set up to test the braking performance of hybrid excitation linear ECB with series magnetic circuit. According to the distribution of air flow field around the hybrid excitation linear ECB, the convective heat transfer coefficients and the convective heat resistance of each heat dissipation surface of the ECB are calculated by the non-dimensional analysis method. In order to verify the accuracy of the thermal network model, the finite element model is used to calculate the temperature variation of the hybrid excitation linear ECB with series magnetic circuit over time.The static and dynamic temperature rise characteristics of the hybrid excitation linear ECB prototype with series magnetic circuit are tested to verify the accuracy and validity of the thermal network model and the finite element model.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TM359.4

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