【作者】 黄涛；

【导师】 潘垣； 阮江军；

【作者基本信息】 武汉大学 ， 高电压与绝缘技术， 2014， 博士

【摘要】 感应电机的变频调速大大拓宽了感应电机的应用面,但也极大提高了其振动噪声的控制技术难度,成为变频调速感应电机的技术瓶颈问题,尤其是要求低振动噪声的应用场合。电磁激振力、空气流体及机械摩擦是引起电机振动噪声三大主要的宏观因素。当电机转速提高时,空气流体及机械摩擦是引起振动噪声加剧的主要因素。电磁激振力则受电机齿槽结构、铁磁材料、转子同心度等众多因素的影响,尤其对于变频调速感应电机,定子电流谐波含有大量的高次谐波,成为振动噪声分析的技术难点。对于变频供电感应电机的减振降噪,现阶段主要从两个方面进行研究,一方面是电机本体的电磁及结构设计,另一方面则是变频器控制策略。本课题来源于国防科技工业局科技项目。本文以感应电机本体的电磁、结构分析为研究重点,从三个方面对变频供电感应电机电磁振动展丌深入研究。一是利用解析法推导电压源、磁通密度、电磁激振力及振动的关系,尤其是变频供电引起的高次谐波对电机振动产生的影响。二是采用数值计算法,对变频供电条件下感应电机端部、本体进行瞬态磁场分析,讨论电磁激振力中频谱分和特征,研究电磁激振力作用于定子铁芯对振动产生的影响。三是,采用实验法验证解析法与数值计算法的正确性。本文研究内容主要包括以下几个部分：第一部分对电磁力的计算方法进行了简单的介绍,主要包括洛伦兹力法、麦克斯韦应力张量法及虚位移法。其次,根据经典的麦克斯韦应力张量法对电磁噪声的主要振动源——径向电磁力进行研究。最后,分别推导了正弦供电和变频供电条件下的径向电磁力的计算方法。第二部分采用数值计算法对变频供电端部磁场进行研究,以往研究通常采用等效法进行处理,即通过实验去获取定子绕组中的电流,将其加载到端部绕组中,进行瞬态计算。该方法可以避免考虑转子旋转引起3维运动涡流场问题,但是在测量过程中不可避免存在误差。为此,本文自行设计了一款专用于船用推进动力装置电磁振动分析的实验样机,采用三维场路耦合时步有限元法,考虑转子旋转的影响,联立电磁场方程、电路方程及转子运动方程,直接加载电压源求解瞬态端部磁场,对比变频供电端部磁场测量结果,推断出变频供电端部磁场的频谱特征。第三部分采用二维场路耦合时步有限元法处理变频供电感应电机本体电磁激振力的计算问题,包括径向电磁力和切向电磁力。对振动影响较大的径向电磁力进行了重点研究。首先,分析了正弦供电与变频供电中定子线电压、定子相电流、径向电磁力的频率特征的异同。其次,验证了径向电磁力频谱中的槽频成分。再次,讨论了不同负载对定子线电压、定子相电流、径向电磁力的频率的影响。最后,分析了开关频率对径向电磁力的影响。第四部分对变频供电感应电机的定子振动特性进行了分析,提出了一种瞬态磁—结构间接耦合法处理随时空变化的非正弦电磁力引起的定子铁芯振动响应问题,通过对比实验测量的振动加速度频谱特征,验证了该方法的可行性。最后,对中等功率异步电机进行了电磁振动实验研究,获取的试验数据可用于异步电机参数匹配性研究,进而为低噪声异步电机的设计提供参考,指导工程设计。更多还原

【Abstract】 Frequency control of induction motors’speed has greatly broaden the application of induction motor,but also greatly increase the difficulty of its noise and vibration control technology.It has become the technological bottlenecks of inverted-fed induction machine, especially in those applications which requires low noise and vibration.Electromagnetic excitation force, air flow and mechanical friction are the three main macroeconomic factors of motors’vibration and noise. The latter two are the main factors causing noise and vibration intensified with the increase of the motor speed Electromagnetic excitation force is affected by many factors, such as motor alveolar structure, ferromagnetic materials, rotor concentricity, etc. especially for inverted-fed induction machine, the stator current harmonics contains a lot of high order harmonic harmonics,which has become technical difficulty of noise and vibration analysis.The subject comes from the defense industry Bureau of Science and Technology Project.This paper makes deep research of the inverted-fed induction machines’ electromagnetic vibration from three aspects. First, confirm the relationship between the voltage source, the magnetic flux density, magnetic excitation force and vibration with the analytical method, especially for the impact of the motor vibration,caused by high order harmonic in inverted-fed. Second, make transient magnetic analysis of the ends of the induction machine and the body’s magnetic field in inverted-fed conditions with numerical calculation method. It can discuss the harmonic frequency components of electromagnetic excitation force and the vibration impact of electromagnetic excitation force when the force is applied on the stator core.The third is to verify the feasibility of analytical and numerical calculations using the experimental method.This paper mainly includes the following sections:In the first part, it has carried on a simple introduction of the electromagnetic force’s calculation method, which mainly including Lorentz force method an Maxwell stress tensor method and virtual displacement method.Then this part has also studied radial electromagnetic force which is the main vibration source of electromagnetic noise according to the classical maxwell stress tensor method. Finally, the calculation method of radial electromagnetic force is deduced respectively under the condition of the sine power supply and converter’s power supply. The second part is the research of the ends of magnetic field through numerical calculation method in inverted-fed condition. For inverted-fed, traditional calculation are often used the method of equivalent, namely through the experiment to obtain the current in the stator winding and loads it into the end windings then make transient calculation. This method can avoid considering the three-dimensional vortex field problem caused by the rotor rotating, but in the presence of measurement error is inevitable. Therefore, this chapter uses a three-dimensional field circuit coupled stepping finite element method, considering the rotor rotates, electromagnetic field equations,circuit equations and the equation of rotor motion to solve transient magnetic field of winding ends.Magnetic field measurement results were compared with the calculation results to infer the spectral characteristics of the winding ends’magnetic field.In third part, electromagnetic excitation force of inverter-fed induction machine body’s calculated problem is solved by two-dimensional field processing circuit coupled FEM. It has calculated inverter-fed induction machine body’s radial and tangential electromagnetic force and focused on radial electromagnetic force which has greater impact on vibration. Firstly, it make a analysis of frequency characteristics about the stator phase current,the stator voltage, radial electromagnetic force similarities and differences in both sinusoidal-fed and inverter-fed conditions. Secondly, it verifies the radial slot frequency component in Radial electromagnetic force spectrum. Then, make a discuss about the effects of different loads on the stator voltage, the stator phase current,the radial electromagnetic force. Finally, It analyzes the impact of the switching frequency on the radial electromagnetic force.Section IV presents a transient magnetic-structural treatment of transient dynamics indirect coupling method to solve transient dynamic response problems caused by inverter-fed, taking into account changes of radial electromagnetic force in time and space (neither static, and non-sinusoidal force) and make an analysis of the response of the stator structure of the radial electromagnetic force, solving the motor structure’s displacement, velocity, acceleration, and concerned acceleration spectral characteristics, etc. It provides an important theoretical guidance for the structural design of the motor vibration.更多还原