Methodology Approach Using Harmonic Synthesis as Simulation Method for Investigation of Power Network with Non-Linear Loads

The paper deals with analysis and synthesis of non-harmonic and non-linear sources and appliances, and their interaction with harmonic power supply network. Basic idea is based on knowledge of harmonic spectrum of the sources and/or appliances, respectively. Obviously, one need to know voltage harmonic components of voltage sources （renewable with inverters,...）, and current harmonic components generated by non-linear appliances （rectifiers,...）. Method of investigation lies on decomposition of real electric circuit into n-harmonic separated equivalent schemes for each harmonic component. Then transient analysis will be done for each scheme separately using ＂impedance harmonic matrices＂. The important fact is that each equivalent scheme is now linearized and therefore easily calculated. Finally, the effects of each investigated schemes arc summed into resulting quantities of real non-linear electric circuit.

Simulation for MSS-2 low-perigee elliptical orbit satellites:an example of lithospheric magnetic field modelling

A future constellation of at least four geomagnetic satellites(designated Macao Scientific Satellite-1(MSS-1)and Macao Scientific Satellite-2(MSS-2))was recently proposed,to continue high-quality geomagnetic observations in the post-Swarm period,focusing especially on collecting data that will provide a global,three-dimensional survey of the geomagnetic field.In this paper,we present a simulation of two years of orbits(2020.01.01-2022.01.01)of two satellites(tentatively denoted as MSS-2)that are constellated in elliptical(200×5,300 km)low-perigee orbits.By comparing error variances of Gauss coefficients,we investigate the sensitivity of lithospheric magnetic field modelling to data collected from various satellite orbits,including a near circular reference orbit of 300×350km,and elliptical orbit of 180×5,300 km,220×5,300 km,200×3,000 km and 200×1,500 km.We find that in two years the two MSS-2 satellites can collect 35,000 observations at altitude below 250 km,data that will be useful in advancing the quality of lithospheric magnetic field modelling;this number of observations reflects the fact that only 4.5%of the flight time of these satellites will be below250 km(just 6.4%of their flight time below 300 km).By combining observations from the MSS-2 satellites’elliptical orbits of 200×5,300km with observations from a circular reference orbit,the variance of the geomagnetic model can be reduced by a factor of 285 at spherical harmonic degree n=200 and by a factor of 1,300 at n=250.The planned lower perigee of their orbits allows the new satellites to collect data at unprecedentedly lower altitudes,thus dramatically improving the spatial resolution of satellite-derived lithospheric field models,(up to 80%at n=150).In addition,lowering the apogee increases the time interval during which the satellites fly at near-Earth altitudes,thus improving the model predictions at all spherical harmonic degrees(around 52%-62%at n=150).The upper limit of the expected improvement to the field model at the orbital apogee is not as good as at the perigee.However,data from the MSS-1 orbit can help fill the gap between data from the MSS-2 orbits and from the circular reference orbit for the low-degree part of the model.The feasibility of even lower-altitude flight requires further discussion with satellite engineers.

Quantified simulation research on harmonious factors in the leadership teams of aerospace enterprise group

A brief account of basic connotation and evaluation indexes system of harmonious leadership teams is given. On this basis, a simulation model is built by using the ARENA simulation software and the quantified simulation is carried out for the factors of harmonization of aerospace enterprise leadership teams. Moreover, by taking the characteristics of aerospace enterprise leadership teams into consideration, the comparison of harmonization quantified results of several typical leadership teams, especially on the comparative analysis of influencing degrees of moral characters and capabilities on the leadership teams overall harmonization is emphatically discussed. Finally, a conclusion is drawn.

Harmonic amplitude-phase adaptive control and its application in three-axis simulators

This paper proposes a compensation method for using the Harmonic Amplitude-Phase Adaptive Control(HAPAC)to increase the precision of sinusoidal motion simulators. It also expounds on the HAPAC principle and structural disposition, develops the HAPAC control laws and analyzes the system stability in the HAPAC. A method for further improving the precision using online identification of the system’s frequency-response models is presented. The tested data and tracking errors of the simulator demonstrate that the HAPAC makes the sinusoidal motions achieve higher precision than the common classical controls. The HAPAC can also be used in other tracking systems of precision sinusoidal motions.

Dynamic simulation on rubber spring supporting equipment of vibrating screen

By ANSYS, dynamic simulation analysis of rubber spring supporting equipment used in vibrating screen was made. The modal frequency, mode, and harmonic displacement under working frequency were obtained. Variation of rubber spring supporting equipment＇s dynamic performance was discussed first, which is under the condition of existing spring stiffness difference and exciting force bias. Also, the quantitative calculation formulas were given. The results indicate that the performance of vibrating screen is closely related with rubber spring supporting equipment＇s dynamic performance. Differences of springs＇ stiffness coefficients reduce the modal frequency reduced, decrease the dynamic stiffness, and increase vibration displacement. Exciting force bias induces a larger lateral displacement. When rubber springs＇ stiffness coefficients exist, differences and lateral force accounts for 5% in total exciting force; rubber spring supporting equipment＇s side swing is larger than 1 mm, exceeding the side swing limit.

Analysis of the Electric Locomotives Neutral-section Passing Harmonic Resonance

For the further analysis and suppression of the electric locomotives neutral-section passing overvoltage, on the basis of theoretical analysis of the neutral-section passing harmonic resonance conditions, this paper establishes simplified harmonic resonance simulation models of the electric locomotives neutral-section passing using MATLAB/Simulink, and makes the overvoltage simulation analysis of the existing electric locomotives neutral-section passing system in the event of a harmonic resonance. Results show that when the system harmonic resonance occurs, the operating overvoltage of the neutral-section passing is serious intensified by the overvoltage of the harmonic resonance, which will make the voltage of the pantograph collector head exceeding 100kV. This amplitude of the overvoltage will breakdown the air gap, which will be a serious threat to the safety operation of the electric railway. However, this kind of neutral-section passing overvoltage hasn’t cause the attention in the field and theoretical studies, which need more analysis and verification in the further study.

Computer simulation of short-circuiting transfer welding under waveform control on inverter power source

A simulation model is introduced about the non-linearity process of short-circuiting transfer in CO2 arc welding for displaying the interaction between the inverter power source and welding arc under waveform control. In the simulation model, the feedback signals of current and voltage are taken respectively at the different phase in a short circuit periodic time and applied to the PWM （pulse width modulation） module in a model of inverter power source to control the output of power source. The simulation operation about the dynamic process of CO2 short-circuiting transfer welding is implemented on the founded simulation model with a peak arc current of 400 A and a peak voltage of 35 V, producing the dynamic arc waveforms which can embody the effect of inverter harmonic wave. The simulating waveforms are close to that of welding experiments.

Application of Scale Relativity to the Problem of a Particle in a Simple Harmonic Oscillator Potential

In the present work, Scale Relativity (SR) is applied to a particle in a simple harmonic oscillator (SHO) potential. This is done by utilizing a novel mathematical connection between SR approach to quantum mechanics and the well-known Riccati equation. Then, computer programs were written using the standard MATLAB 7 code to numerically simulate the behavior of the quantum particle utilizing the solutions of the fractal equations of motion obtained from SR method. Comparison of the results with the conventional quantum mechanics probability density is shown to be in very precise agreement. This agreement was improved further for some cases by utilizing the idea of thermalization of the initial particle state and by optimizing the parameters used in the numerical simulations such as the time step and number of coordinate divisions. It is concluded from the present work that SR method can be used as a basis for description the quantum behavior without reference to conventional formulation of quantum mechanics. Hence, it can also be concluded that the fractal nature of space-time implied by SR, is at the origin of the quantum behavior observed in these problems. The novel mathematical connection between SR and the Riccati equation, which was previously used in quantum mechanics without reference to SR, needs further investigation in future work.

用Solidworks simulation premium仿真分析热泵管路应力简化试验操作

商用空气源热泵系统,管路粗且走向复杂,弯位多,测试应力、振幅时,常常由于测试应力的设备通道数量不够,导致少测和漏测,市场就可能出现管路振断、振裂的情况,或者试验时间很长,反复测试很多点,占用大量试验资源。本文应用有限元分析,先对管路进行仿真分析,找出振动、应力相对大的位置,通过试验验证,确认有限元分析来准确定位应力大的位置的可行性,这样,测试前均对配管进行仿真,提升检测命中率,为公司节省了大量试验资源。

The research of load spectrum between flexible gear and wave generator of harmonic drive

The harmonic drive is a kind of gear transmission that uses wave generator to produce controllable soft round elastic deformation and engages with rigid gear to transmit motion and power. The load distribution on the surface of the flexible gear and wave generator is an important parameter of studying the deformation of flexible gear and flexible bearing outside the wave generator and is also a necessary condition for studying the fatigue damage of flexible gear under alternating load. In this paper, a 3D model of 32-type 80：1 harmonic drive is build. Based on the generalized Hooke law, a hypothesis of load distribution which is proved to be validity by using finite element simulation is proposed on the interface of flexible gear and wave generator. On this base, the mathematic model and the quantitative calculation formula of the load distribution on the surface of the flexible gear and wave generator are proposed which provide a basis for the dynamic analysis and the fatigue damage of harmonic gear drive.

The Effect of Leakage Inductance on High Frequency Transformer Harmonics

Nowadays, switching power supplies are used in almost all electronic devices to regulate the voltage amplitude. The only obstacle on using these devices is the production of high frequency harmonics that violates different standards such as （FCC, VDE, 461 ）. In this paper the sources of various noises in switching power supplies will be introduced. Then, using appropriate model for high frequency transformers, a sample switching power supply will be simulated. In this simulation, the effect of leakage inductance on current and voltage waveforms of the input and output switches, which are the main cause of common mode differential mode noises and radiations, will be discussed and harmonically analyzed. Finally the experimental results will confirm the simulation conclusions.

基于自抗扰的永磁同步电机附加谐波损耗抑制方法

针对永磁同步电机在变频器供电时,由时间电流谐波所引起的附加谐波损耗过大及难以在电机初始设计时被考虑到的问题,采用场路耦合联合仿真模型来计算电机的附加谐波损耗,并以4台现有的表贴式永磁同步电机为例,通过实验验证了场路耦合联合仿真模型的有效性,为电机设计之初附加谐波损耗的选取,以及后续温升的计算提供了前期计算的方法。同时提出一种基于自抗扰技术的附加谐波损耗抑制方法,设计一种适用于永磁同步电机矢量控制的自抗扰控制器,并从理论上验证了自抗扰控制器对于时间电流谐波的抑制作用,以及针对自抗扰控制器参数众多调参困难的问题,给出一种参数整定方案。最后通过引入所设计的自抗扰控制器,对电机的时间电流谐波进行计算和分析,使电机的附加谐波损耗降低了68.1%,为同类型电机的附加谐波损耗抑制提供了一种有效的方法。

机械设备用感应电机电磁力动态特性计算与研究

机械设备用感应电机的动态性能是不可忽略的设计要求。为抑制电机动态电磁振动和噪声水平,展开了对电机电磁力动态特性分析及相应削弱措施的研究。首先利用经典气隙谐波磁场理论,确定磁场中的谐波磁势和谐波磁导来源,由此再通过张量法计算电机径向电磁力,并对比主要谐波分量的幅值、极对数和频率特征。然后采用有限元仿真和傅里叶分解法,确定电磁力时空行波的基本特征,推断主要力波的谐波磁场产生来源。结果表明谐波径向力绝对幅值的变化很难影响其占基波的相对比值。最后建立磁性槽楔理想模型对比仿真,谐波电磁力的削弱程度与槽楔磁导率正相关,样机振动测试试验间接验证了磁性槽楔的优越性,为电机动态特性研究及优化设计提供理论依据。

绝对式纳米时栅传感器栅尺污染误差分析与抑制方法研究

针对服役状态下油污降低位移传感器精度和可靠性的问题,本文基于绝对式纳米时栅传感器,开展了栅尺油污污染误差分析与抑制方法研究。首先阐述了绝对式纳米时栅传感器测量原理;其次建立了栅尺油污污染的数学理论模型和电场仿真模型。通过理论和仿真分析表明:均匀油污污染对传感器没有影响,非均匀油污污染主要引入一次谐波误差,并且误差随着污染油污的厚度和宽度的增加而增加;最后搭建实验平台验证了以上理论分析的正确性。同时提出差动结构,有效抑制了一次谐波误差,提高了传感器抗污能力。研究油污造成的误差影响对提高传感器环境适应性有重要意义,同时也为提高传感器长期可靠性和增强环境适应性提供了理论基础。

基于分数阶小波变换的电力系统谐波检测方法

针对稳态和暂态谐波检测易受噪声干扰的问题,提出一种基于分数阶小波变换(fractional wavelet transform,FRWT)的电力系统谐波检测方法。首先,通过快速傅里叶变换(fast Fourier transform,FFT)检测出各频谱的频率,根据频率确定分解层数;其次,利用FRWT对信号进行分解和重构,实现基波与各次谐波分量的分离;最后,对各次谐波分量进行Hilbert变换(Hilbert transform,HT),获取各次谐波分量的频率和幅值检测结果以及暂态扰动的起止时刻。对多种谐波信号的仿真试验结果表明,FRWT方法可以有效实现对含噪信号中稳态和暂态谐波的检测,即使信噪比较低也能保证各项结果的检测精度,证明FRWT方法是检测谐波的一种有效新方法。

基于电机振动的动车组牵引逆变器故障诊断研究

牵引逆变器的安全性和可靠性对高速动车组车辆的稳定运行至关重要,为了对逆变器工作状态进行识别,文章结合车辆系统动力学,提出了一种基于电机振动信号分析的故障诊断方法。将电机振动信号作为监测对象,通过检测逆变器故障时电流畸变引起电机异常振动的特征信号来进行判断。以CRH2型动车组牵引传动系统为例,建立了基于空间矢量脉宽调制策略下的三电平牵引逆变器电路仿真模型,对逆变器结构故障模式进行仿真。仿真结果表明,逆变器故障会显著影响交流侧输出电流谐波含量,尤其是5倍频、7倍频、11倍频、13倍频电流谐波;而这些谐波电流输入到牵引电机后转化为6P(1-s)倍频、12P(1-s)倍频的脉动转矩,并作用于电机,使得其输出振动中含有相应频率的谐波成分。通过对高速动车组实际运行过程中的牵引电机振动信号进行分析可发现,在正常情况下振动信号不明显含有此类谐波频率成分,而当逆变器存在故障时,则会导致在振动信号中该频率信号含量非常明显。因此,文章所提出的基于振动信号分析法能够有效地监测并诊断牵引逆变器工作状态,并具有一定的工程应用价值。

基于MATLAB/SIMULINK的SS_(3B)型电力机车仿真模型

利用MATLAB平台上的仿真软件SIMULINK建立了SS3B型电力机车的数字仿真模型。在仿真模型中比较准确地模拟了直流电机的反电势,利用机车牵引特性函数与整流回路的关系对导通角α进行了计算,得到电力机车交流侧电流;利用MATLAB提供的FFT函数对电流进行快速傅立叶变换,得到电力机车注入牵引网的基波和各次谐波电流。通过仿真结果分析,可以看出此仿真模型具有正确性、有效性和可行性。

空载下礼帽形柔轮的变形分析与试验验证

柔轮作为谐波减速器的核心部件,其装配过程中的接触应力和变形分布,影响着可靠性寿命。采用礼帽形柔轮进行有限元的装配模拟过程分析,分别提取柔轮长短轴以及齿圈前后端并进行变形与应力分析。结果表明,长轴和短轴处变形与实际相符,呈现线性降低趋势;齿圈前后端变形呈周期性变化。等效应力在长轴和短轴的轴向齿宽部分呈下降趋势。齿圈前后端较大等效应力产生在长轴和短轴处,而最大等效应力出现在筒底的过渡区,为327.91 MPa,低于材料许用强度。运用高精度三坐标测量机对柔轮装配过程变形测量,以长轴和短轴的轴向齿宽方向间隔1 mm作为检测点,将测量结果与仿真结果对比验证,误差结果在5%以内,验证了该仿真分析的适用性。为后续的谐波减速器设计提供数据支持。

基于谐波分析的封装-电路多物理场耦合仿真方法

场-路耦合仿真可以支持跨越芯片-封装-系统的多层级协同分析,多物理场仿真能够对多物理约束下芯片封装的信号完整性、电源完整性以及可靠性进行提前设计.因此,针对场-路结构的多物理场耦合仿真能够实现在初期对芯片封装的设计方案进行筛选和优化,是先进封装仿真技术最重要的发展方向之一.本文基于场-路耦合仿真和多物理场耦合仿真方法的最新研究进展,提出针对非线性场-路结构的频域仿真方法以及电磁-热耦合计算方法 .该方法能够解决基于时域仿真方法的场-路耦合仿真的长时间迭代问题,实现多物理约束下非线性场-路结构的电磁与热特性快速分析.计算结果验证了本文方法的准确性和高效性.

随机脉宽调制的Simulink仿真研究

应用Matlab仿真平台,开发了随机脉宽调制的Simulink仿真文件,运用此仿真文件,研究了逆变器的谐波能量分布随随机增益变化的规律,仿真结果有助于实际装置的研制。