等效电路

The circle diagram of the induction motor was educed by analyzing the motor's equivalent circuit,then its application to computation was demonstrated by illustration.

首先从感应电动机的等效电路分析得出电动机的圆图，然后举例说明它们的应用计算，从而说明电动机的圆图和等效电路一样，都是分析计算电动机问题的有效工具。

The device parameter as well as resonance frequency,mechanical quality factor and work band width were determined by the equiv- alent circuit input impedance admittance circle diagram .

分析压电式超声波换能器的等效电路，并由等效电路输入阻抗的导纳圆图确定了换能器的元器件参数以及谐振频率、机械品质因数和工作带宽等特征参量。

First, this article introduced the status of the electromagnetic launch technology in general. Then, the author further introduced a new principle of coil launch technology and its inductance in the equivalent circuit which are based on the principles of linear motor. It is a more comprehensive thought in the study. Third, in the building of the power supply system, the most important things are the trigger control loop structures, the gap switch debugging, the measurement of the impact current, and electromagnetic interference protection. Finally, I introduced the experiment, the simulation analysis of some questions in the experiment. The most important thing is the analysis of the equivalent circuit of the stator windings. And the author build a simulation model based on it.

本文首先介绍了电磁发射技术的概况；其次，基于直线电机的原理，介绍了直线驱动线圈发射技术的基本原理、等效电路和回路电感计算，得到了较完整的课题研究思路；第三，搭建电源系统，工作的的重点是触发控制回路的研制、间隙开关的调试、冲击电流的测量、电磁干扰防护措施；最后，介绍了课题实验情况，对实验中产生的问题进行了仿真分析，其中以定子线圈的等效电路的分析为重点，建立了仿真模型，并对参数的变化进行了仿真研究，为后续的实验研究提供参考。

In this thesis, by means of the principle of energy conservation, the small-signal transfer functions of interleave boost power factor correctors are derived. The transfer functions include the open-loop transfer function of interleave PFC and the transfer function of small-signal circuit with parasitic elements.

中文摘要本论文利用能量守恒定理推导交错式功率因数修正器(interleave power factor correctors)之等效电路模型，所推导的模型包括开路交错式功率因数修正器的小讯号等效电路以及含寄生元件效应之小讯号转移函数。

Relationship between IL and relevant network parameters is presented by network theory. Network structure of EMI power line filter and its computation method for IL are discussed. Common mode and differential mode equivalent circuit model of single-phase power line filter and the high frequency distribution parameters model of filter device are established. Meanwhile, the main characters of soft ferrite are analyzed, and its implement on the EMI power line filter and its equivalent circuit model are given. According to the preceding theory, the software for IL of power line filter and the design of filter inductor are programmed. The difference between the imitative and practical results is analyzed, and the rational of the equivalent circuit model is tested.

文中应用网络理论分析了EMI电源滤波器的插入损耗与相关网络参量的关系，讨论了EMI电源滤波器的基本网络结构及其插入损耗的计算方法，建立了单相电源滤波器的共模及差模等效电路模型及滤波器件的高频分布参数模型，然后分析了软磁铁氧体材料的主要性质，讨论了软磁铁氧体在EMI电源滤波器中的应用，建立了软磁铁氧体磁芯的等效电路模型，最后根据以上理论编制了滤波器插损分析软件和滤波电感设计软件，并对软件仿真结果与实际测试结果进行了对比分析，验证了各个等效电路模型的合理性。

Based on the theory of the electromechanical analogy and the special wave equation,the equivalent circuit of the exponential acoustic waveguide was derived,the formula of its impedance transformation was obtained.

基于机电类比原理，从特殊形式波动方程出发，推导出了指数形变截面声波导管的等效电路，从等效电路推导出了声波导管的阻抗转移公式。

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

Secondly, the relationship between the coil impedance and its liftoff for different materials are obtained using separation of variables and numerical calculation methods.

为考察电涡流传感器中等效电路的适用性，本文从被测体材料角度出发，在分析等效电路基础上，采用分离变量法和数值计算法，得到不同被测材料下探头线圈阻抗与提离高度的关系，并与从等效电路得出的结论比较，确定等效电路的适用性，同时考察被测体厚度对线圈阻抗的影响，最后对得出的结论进行理论分析。

An engineering approximately design method-equivlent circuit isalso introduced by equilent circuit of waveguide ET-junction and principle of symmetry and of multiplication of matrix.

本文同时依据对称性原理、ET接头的等效电路及传递矩阵的乘积原理建立了波导谐波滤波器的近似工程设计方法——等效电路法，指出等效电路法虽然精度有限、但计算时间很快，可以进行基、谐波全频段分析。

There are few equivalent circuit modeling methods for UWB antennas. This thesis compares the characteristic of some existing modeling methods and presents a general and precise modeling method for UWB antennas. Firstly, establish the narrowband model of the antenna, and compute the difference between input admittances of the antenna and its narrowband model. Secondly, implement rational approximation of the difference to build the macromodel, and convert it into SPICE equivalent circuits. Lastly, combine the narrowband model and the macromodel to form the ultimate equivalent circuit model of the antenna.

本论文针对目前UWB天线等效电路建模方法比较少的现状，结合现有的天线建模方法的一些特点，研究了一种系统通用、模型精度高的新建模方法：首先建立超宽带天线的窄带模型，计算天线及其窄带模型导纳的差值；接着对差值进行有理多项式拟合，得到相应的宏模型，并转化为SPICE等效电路；最后合并窄带模型与宏模型电路，得到天线等效电路模型。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。