General synthesis techniques for coupled resonator networks

This article presented general techniques for the synthesis and design of coupled resonator filters. The synthesis of the prototype circuit focuses on the compatibility between the coupling topology and the filtering function to be realized, providing some guidelines to select a proper coupling topology and to solve the coupling matrix synthesis problem. The dimensioning of the distributed filter is centered on parameter extraction techniques.     

Artificial neural network-based prediction technique for transformer oil breakdown voltage

This paper presents an artificial neural network (ANN)-based modeling technique for prediction of transformer oil breakdown voltage. This model comprises transformer oil service period, total acidity and water content while preserving the nonlinear relationship between their combinations for predicting transformer oil breakdown voltage. The model results are compared with those obtained by various modeling techniques such as ANN-based model for transformer oil breakdown voltage as a function of its service period, a polynomial regression model for transformer oil breakdown voltage as a function of its service period and a multiple linear regression model for transformer oil breakdown voltage as a function of its total acidity, water content and service period. A quantitative analysis of various modeling techniques has been carried out using different evaluation indices; namely, mean absolute percentage error and actual percentage error at each service period. The results showed the effectiveness and capability of the proposed ANN-based modeling technique to predict transformer oil breakdown voltage and justified its accuracy.     

Narrow-band microwave filter design

In this article, Dishal's concepts, EM simulation, and the port-tuning concept are combined as a powerful procedure for narrow-band filter design. When applied to an EM-based filter prototype, port tuning gives a direct indication of the magnitude and direction of the tunings needed to correct coupling errors and resonator frequency errors. An EM-based filter prototype potentially captures all the physics of the real hardware and includes second-order effects that may be impossible to describe using analytical models. After iteratively reducing all the errors in the EM-based prototype, the first hardware prototype that was built will meet performance goals. This design methodology can be applied to simple all-pole Chebyshev filters and to more complex cross-coupled filters that place transmission zeros in the stopbands.     

Microwave filter design by synthesis and optimization

In this article, a process that might be described as "synthesis and approximation" was outlined. Starting from an exact prototype, the desired physical configuration using equivalent circuits and corrections to the resonators due to the influence of the coupling networks was approximated. A process that might be described as "approximation and optimization" was also outlined. Starting from an approximate filter network, optimization can be used to find an exact equal ripple solution. The starting point can be generated using synthesis or narrow-band approximations when appropriate. Applying optimization in an intelligent way allows the designer to circumvent some of the limitations of the classic ladder synthesis method. This article explores some ways to mix approximate filter dimensioning (based on network synthesis) and optimization (based on EM modeling), allowing a fast and accurate design of microwave filters     

A time-domain three-phase power system impedance modeling approachfor harmonic filter analysis

A time-domain method for impedance modeling of an unbalanced, three-phase power transmission and distribution network using three-phase measurements of bus voltage and injected current waveforms is presented. An impedance model seen at a bus where a harmonic filter is to be installed is calculated for each harmonic frequency, and the effect of placing the filter at the bus is then analyzed at these frequencies. As the configuration or operating condition of the power system varies, the estimated model changes accordingly, provided updated measurements are available. Hence, the effect of the harmonic filter under different system configurations or operating conditions is analyzed, and the information from this analysis is used for online harmonic filter control. Impedance models estimated by the proposed method are applied in filter design and performance analysis with actual recorded data, and the results are presented     

A knowledge-based approach to optimize switching in substations

Automatic sequence switching has been an important pursuit in the field of substation automation. An intelligent approach to the optimization of switching sequences in electric substations is presented. The optimal sequence switching problem is stated. A knowledge-based model of a substation switch network organized in a trilevel hierarchical structure is suggested, and a set of basic techniques suitable for the general task of network reorganization is given. An intelligent optimal sequence switching strategy for substations based on modeling techniques is presented. An expert system in Prolog used to formalize the sequence of switching operation and application in substations is described     

Direct synthesis techniques for general Chebyshev filters: lowpass,highpass, and bandstop cases

Conventional synthesis techniques for general Chebyshev lowpass, highpass, and bandstop filters are usually based on general Chebyshev filtering function, from which lowpass prototype is set up. By applying the lowpass to lowpass, highpass, or bandstop frequency transformation on realization networks of lowpass prototypes, final realization networks of general Chebyshev lowpass, highpass, and bandstop filters are obtained. In this paper, direct synthesis techniques for general Chebyshev lowpass, highpass, and bandstop filters are discussed. Transmission zeros can be placed wherever they are desired to control the performance of the filters. Unlike conventional synthesis techniques, they derive filtering polynomials constituting network parameters directly in the lowpass, highpass, or bandstop domain, which might find applications in analogue and digital filter design. Several examples are presented for demonstration. Copyright © 2015 John Wiley & Sons, Ltd.     

开关电源的建模与优化设计研究

针对目前无法建立开关电源精确数学模型的情况下，研究一种有效的开关电源工程化设计方法。给出了一种开关电源拓扑结构，详细介绍了采用实验和仿真结果建立基于Matlab环境下的开关电源神经网络模型的方法，以及利用该非线性神经网络模型结合遗传算法理论对开关电源的电路参数进行优化设计的过程。在此基础上研制了开关电源样机，并对开关电源优化模型和样机进行了仿真与试验研究分析。结果表明，采用这种优化设计方法制造的开关电源的动态性能、静态性能均达到了预期指标。     

Space mapping

Microwave CAD has its roots in the 1960s [1]. Its practice saw the enrichment of circuit-based model libraries, advances in EM and circuit simulation accuracy, and the refinement of microwave optimization technology. In 1994 [24], space mapping emerged: a powerful yet simple mathematically based technology that takes advantage of progress in the aforementioned key areas. Space mapping has since developed into an approach of choice for EM-based design. In this article, we provided a general framework for the space-mapping optimization concept. We illustrated space-mapping optimization through a simple bandstop filter. We demonstrated the robustness of the technique by performing an accurate design of an interdigital filter. We reviewed state-of-the-art developments in space mapping that feature implicit space mapping; output space mapping, gradient-based space mapping as well as trust region methods; surrogate model choice and adaptive space mapping; tuning space mapping; and space mapping for device modeling. We reviewed implementation techniques and demonstrated the SMF space-mapping software package.     

交直流配电网系统中准Z源网络的小信号模型分析与验证

配电网中Z源网络的引入可以灵活控制电压的输出,实现高效率的电能变换。为了详细分析准Z源网络拓扑的模型特征,利用状态空间法和小信号建模方法提出、分析并验证了一种应用于配电网中准Z源网络的小信号模型特征。首先,利用状态空间法推导了准Z源网络的数学模型;然后,利用小信号模型对准Z源网络进行暂态分析,并得出电感电流和电容电压传递函数。另外,详细分析了两种传递函数的零、极点分布情况,并得出了系统稳定性变化的特征。最后,利用MATLAB/Simulink软件仿真的结果和物理样机试验验证了所提方法的有效性。     

Q‐factor evaluation,design and accurate EM performance of multilayer dielectric filters

In this contribution we present the design of an optical dielectric multilayered filter by using a transmission‐line prototype. Each resonator of the prototype is realized by means of a stack of dielectric layers by equating the Q‐factor of the stack with that of the corresponding resonator of the prototype. We then compare the analytical results with numerical ones obtained by the finite element method (FEM). We extend the theory to a structure formed by periodic multilayer resonators. Copyright © 2006 John Wiley & Sons, Ltd.     

Diplexer design using EM and circuit simulation techniques

This article investigates a diplexer design technique utilizing the strengths of both EM- and circuit-based simulators to provide accurate results with reduced computation times. The EM circuit cosimulation technique effectively reduces the overall design time in passive component design, while achieving accurate results. This method can be extended to other passive component designs, such as comb-line filter and dielectric resonator filter, with a higher-order mode waveport calculation     

基于IronPython的YIG调谐滤波器自动建模

针对YIG调谐滤波器仿真设计过程中大量的复杂建模问题,提出采用IronPython脚本语言实现自动建模的方法。通过SharpDevelop实现可视化界面编程,采用VS2013+PTVS开发基于IronPython语言的ANSYS EM脚本,实现了0.38~2 GHz、2~6 GHz、6~18 GHz和18~26.5 GHz等四种YIG滤波器的磁路与谐振结构的参数化自动建模,具有一键调用、模型参数化修改、全自动化建模、后续新器件可集成等功能。每个模型建立耗时约40 s,对于提高YIG滤波器设计效率,实现知识共享具有积极的意义.     

Power converter simulation module connected to the EMTP

A novel approach for power converter simulation in the electromagnetic transients program (EMTP) is presented. It is based on simultaneous interfacing of a converter simulation module with the EMTP network equations. Hybrid analysis, demonstrated to be more general than the compensation method, is used to model the nonlinear converter module network. The procedure used to formulate hybrid port equations is general and can be used for any converter module network with nonlinear branch functions. The valve model selection has no theoretical restrictions, and the particular case of valve modeling by ideal switches is simple to accommodate. The new approach is more general and efficient than the standard EMTP method for power converter simulation. Modularity permits incorporation of dedicated initialization procedures and programming of digital control schemes     

Statistical Representation of Distribution System Loads Using Gaussian Mixture Model

This paper presents a probabilistic approach for statistical modeling of the loads in distribution networks. In a distribution network, the probability density functions (pdfs) of loads at different buses show a number of variations and cannot be represented by any specific distribution. The approach presented in this paper represents all the load pdfs through Gaussian mixture model (GMM). The expectation maximization (EM) algorithm is used to obtain the parameters of the mixture components. The performance of the method is demonstrated on a 95-bus generic distribution network model.      

低压塑壳断路器操作机构的虚拟样机建模与弹簧的参数化选择

分析了虚拟样机技术的低压塑壳断路器操作机构的动力学仿真,解决了虚拟样机中锁扣与跳扣之间接触力等的建模关键技术问题,建立了低压断路器操作机构虚拟样机模型。通过弹簧的参数化选择,提高了断路器的接触可靠性与分断性能,从而为设计与优化低压塑壳断路器提供了有效途径。     

基于图模库一体化的继电保护整定计算管理系统网络拓朴分析

本文完成了基于可视化技术的网络建模与拓扑分析的设计与开发工作.该软件采用面向对象技术、可视化技术与数据库技术建立了一个通用绘图平台.它使用可视化技术直接绘成电网图,在屏幕上输入各元件参数,后台程序就能自动进行网络建模与网络拓扑分析,然后基于稀疏技术,利用支路扫描法形成节点导纳阵.本文通过对节点编号的深入研究,提出了一种新型编号方法,大大提高了节点编号速度.     

利用反向传播神经网络研究变压器油多关联参数

介绍用反向传播（back propagation,BP）神经网络对变压器油的重要参数——击穿电压建立预测模型,实现对变压器油性能监测的方法,阐述了网络层数、神经元个数、训练函数的设计过程,样本训练的实验结果证明该网络模型具有较好的预测能力;同时,基于BP神经网络的建模方法建立包括变压器油击穿电压、闪点、酸值、总烃、水分等参数之间关联的BP网络预测模型,将2种模型进行比较发现,网络预测模型的预测结果与实际结果的相对误差较小,从而证明该预测模型具有一定的实际意义。     

动态电压恢复装置中滤波器的设计

针对动态电压恢复器 (DVR)结构特点与工作过程 ,进行了低通滤波器电路拓扑结构、参数及材料的设计。运用频谱特性分析法、阻抗匹配法进行了滤波器的理论分析与设计。采用MATLAB中的simulink组建的DVR模拟系统对滤波效果进行了仿真分析。最后将设计的滤波器接入实际电路进行实验研究。在克服了由于铁芯饱和引起的铁磁谐振问题后 ,实现了运行可靠、符合标准的滤波器     

CASCADE SYNTHESIS OF MONOLITHIC CRYSTAL FILTFRS POSSESSING FINITE TRANSMISSION ZEROS

A simple method for the synthesis of bandpass or bandstop filters possessing finite transmission zeros as a cascade of shunted double-resonator monolithic crystal filter (MCF) sections is given. The lowpass or highpass prototype transfer function is synthesized as a cascade of MCF prototype sections for which explicit expressions for the element values are given. Application of the narrow-band lowpass to bandpass frequency transformation to the prototype network then yields a physically realizable filter with the desired bandpass or bandstop response. An example of the synthesis of a bandstop filter is given to illustrate the approach.