Integrated voltage regulator SPICE model

An integrated voltage regulator SPICE model is presented. The model takes into account the main electrical characteristics (dropout voltage and quiescent current); the thermal effects of the electrical variables; and one of the electrical effects of the junction temperature, the thermal shutdown, a protection system used by many commercial devices     

Assessment of the actual condition of the electrical components in medium-voltage networks

Due to the large amount of electrical equipment and the costs of an individual diagnosis in medium-voltage networks, a general consideration of some representative electrical components is necessary to assess the actual condition of the electrical equipment. For a life model of electrical components, the individual aging phenomena of representative electrical components, as well as the general aging mechanisms of insulating materials, are taken into account in this paper. The aging of insulating materials can be estimated by an electrical breakdown occurring in electrical components so that the relationship between lifetime and failure probability of electrical components may be studied using the life model, the probabilistic failure model, and the enlargement law which are reasonably able to investigate the cause & consequence of failure in medium-voltage networks. Thereby, a new approach is developed for the assessment of the actual condition of electrical components in terms of failure time, failure probability, hazard rate, and other related variables of electrical components in medium-voltage networks. These reliability issues will support the decision-making in future deregulation of the electric energy market. Furthermore the model is verified through some electrical components like conductors, cables, transformers, and circuit-breakers with their specific failure statistics. It is demonstrated that the method is able to assess the actual condition of electrical components in medium-voltage networks with reasonable, accurate data.     

Dynamic Imaging in Electrical Impedance Tomography of the Human Chest With Online Transition Matrix Identification

One of the electrical impedance tomography objectives is to estimate the electrical resistivity distribution in a domain based only on electrical potential measurements at its boundary generated by an imposed electrical current distribution into the boundary. One of the methods used in dynamic estimation is the Kalman filter. In biomedical applications, the random walk model is frequently used as evolution model and, under this conditions, poor tracking ability of the extended Kalman filter (EKF) is achieved. An analytically developed evolution model is not feasible at this moment. The paper investigates the identification of the evolution model in parallel to the EKF and updating the evolution model with certain periodicity. The evolution model transition matrix is identified using the history of the estimated resistivity distribution obtained by a sensitivity matrix based algorithm and a Newton–Raphson algorithm. To numerically identify the linear evolution model, the Ibrahim time-domain method is used. The investigation is performed by numerical simulations of a domain with time-varying resistivity and by experimental data collected from the boundary of a human chest during normal breathing. The obtained dynamic resistivity values lie within the expected values for the tissues of a human chest. The EKF results suggest that the tracking ability is significantly improved with this approach.      

AM noise enhancement in a semiconductor laser with electricalfeedback

A model of a self-heterodyne-type electrical feedback semiconductor laser is presented. The effects of electrical feedback on the AM noise of a semiconductor laser are discussed on the basis of the model. It is shown that the FM noise can be greatly reduced by electrical feedback. However, this reduction is always accompanied by AM noise enhancement. The AM noise can also be reduced by this scheme under some conditions with the enhancement of the FM noise. This means that AM noise reduction and FM noise reduction can be interchanged by using this method. The influence of feedback parameters on the noise is discussed     

Modeling of concentrating photovoltaic and thermal systems

An energy balance model for concentrating photovoltaic and thermal (CPVT) systems is presented. In the model, the CPVT system and its environment are represented using a set of input parameters. The main outputs of the model are the system's electrical and thermal efficiencies. The model accounts for optical losses. Thermal losses are derived from a thermal network model of the hybrid receiver. The solar cell performance is modeled as a function of the temperature and the irradiance. The robustness of the model is demonstrated by a sensitivity analysis of all input parameters. The influence of the operating temperature on the electrical and thermal performances and the overall efficiency of the CPVT system are discussed. The limiting cases of maximum electrical and thermal power outputs are presented. Further, the influence of the concentration ratio on the electrical and thermal performance and on the partitioning of these two power outputs is analyzed in detail. It is shown that high concentration reduces the thermal losses considerably and increases the electrical efficiency. At concentration ratios above 300, the system operates with an overall efficiency of 75% at temperatures up to 160 °C. Copyright © 2012 John Wiley & Sons, Ltd.     

Transient distributed parameter electrical analogous model of TE devices

This paper describes a one-dimensional distributed parameter transient model for thermoelectric devices implemented using analogies between the thermal and electrical domains, where thermal variables are described by their electrical analogues. The resulting electrical network can be tested by means of an electrical simulation tool such as SPICE. This approach facilitates simulation of a thermoelectric module and its interconnections with electronic control circuits and other thermal elements under varying boundary and initial conditions. Capabilities of the model are illustrated from simulations carried out for a free-standing thermoelectric element during the pulse cooling operation. Simulation results fit well with those obtained using other models reported in the literature as well as with numerical solutions.     

Large signal circuit model for LED's used in optical communication

A new lumped equivalent circuit for light emitting diodes (LED's) is presented which models the electrical and optical performance incorporating linear and nonlinear recombination mechanisms. Most of the model parameters can be determined from electrical measurements. The model is tested by experiments with different types of LED's and its use in connection with SCEPTRE is demonstrated by a simulation of a 200 Mbits/s pulse code modulation (PCM) pulse train. Special attention is devoted to the electrical reverse recovery behavior of LED's.     

基于引入取舍规则的Lyapunov指数法的电力负荷预测

基于Lyapunov指数法，在引入取舍规则基础上建立了电力负荷预测模型，并利用此模型对某农电局的电力负荷进行预测，取得了满意的结果。     

Modeling of particle arrangement in an isotropically conductive adhesive joint

An isotropically conductive adhesive (ICA) is a composite material consisting of a nonconductive polymer binder and conductive filler particles. When the filler content is high enough the nonconductive binder is transformed into a good electrical conductor. This transition can be described by the percolation theory. We present a two-dimensional model to analyze the principal influences of the geometrical and electrical properties of the filler particles on the percolation threshold and the electrical resistance of an ICA joint. With this model, the arrangement of the particles within the joint is calculated by considering different types of forces. Taking into account the electrical properties of the particles, the electrical contact behavior is investigated. The goal of this study is to provide a deeper understanding of the changes of the macroscopic contact behavior due to different environmental impacts.     

Selective stimulation of sacral nerve roots for bladder control: astudy by computer modeling

The aim of this study was to investigate theoretically the conditions for the activation of the detrusor muscle without activation of the urethral sphincter and afferent fibers, when stimulating the related sacral roots, Therefore, the sensitivity of excitation and blocking thresholds of nerve fibers within a sacral root to geometric and electrical parameters in tripolar stimulation using a cuff electrode, have been simulated by a computer model. A 3D rotationally symmetrical model, representing the geometry and electrical conductivity of a nerve root surrounded by cerebrospinal fluid and a cuff was used, in combination with a model representing the electrical properties of a myelinated nerve fiber. The electric behavior of nerve fibers having different diameters and positions in a sacral root was analyzed and the optimal geometric and electrical parameters to be used for sacral root stimulation were determined. The model predicts that an asymmetrical tripolar cuff can generate unidirectional action potentials in small nerve fibers. While blocking the large fibers bidirectionally. This result shows that selective activation of the detrusor may be possible without activation of the urethral sphincter and the afferent fibers     

Estimation for a life model of transformer insulation undercombined electrical and thermal stress

A life model for power transformer insulation is proposed. It is the Arrhenius model with a weighting factor for the enhanced reaction under combined thermal/electrical stress. Laboratory tests are used to evaluate the model's parameters. The thermal and thermal/electrical stress aging data on Fish paper are presented and analyzed. The estimates from the life model are close to the experimental results. It is hoped that the life model is extendable to other engineering materials. The model's parameters can be evaluated from two laboratory tests, thermal aging and combined thermal/electrical aging. For the Fish paper, when thermal stress is increased by 30°C, the life is reduced by a factor of 2; at 70°C life was 238 hours and at 100°C life was 120 hours. The material life was further reduced by a factor of nearly 2 when subjected to thermal/electrical stress: at 80°C life was 200 hours, whereas at 80°C and 600 Vac life was 118 hours. Electrical stress is important in accelerating the material degeneration     

QFP封装互连结构电气特性建模与退化分析

互连结构是电子器件与印刷电路板之间机械固定及电气互联的关键部位.针对当前互连结构退化过程监测困难与表征信号难以提取问题,首先,通过分析QFP封装互连结构的失效模式及机理,建立其退化电气模型.在此基础上,搭建实时监测电路,选取外接电容的充电时间为表征信号,并建立退化电气模型参数与充电时间的关系.然后,利用Multisim软件和开发板模拟并验证等效电气模型参数与充电时间的关联关系.最后,利用小系统试验板进行随机振动试验,研究互连结构退化过程.通过分析充电时间响应,并结合互连结构电镜图发现,充电时间能够较好地表征互连结构的失效过程及失效模式.     

Frequency domain modeling of volume conduction of single musclefiber action potentials

An inhomogeneous frequency-dependent model of volume conduction in skeletal tissue is used to calculate a transfer function between injected membrane current and extracellular action potential in the frequency domain. This model accounts for tissue structure and microscopic electrical parameters (intra- and extracellular conductivities and membrane impedance) and represents the volume conductor by an extensive electrical network. Results obtained with the model are compared with those of a conventional homogeneous volume conductor model. The comparison shows a significant influence of tissue structure and microscopic electrical parameters close to the source. As a result, the transfer function close to the source is less sensitive to the frequency content and conduction velocity of the membrane current, compared with results of the homogeneous volume conductor approach     

声表面波器件二阶效应PSPICE仿真

提出了声表面波器件二阶效应的等效电路模型,它应用P矩阵法从理论上推导了声表面波器件二阶效应表达式,得到表征二阶效应的电特性参数,应用电网络理论综合出具有相同电特性的等效电路模型,PSPICE仿真结果与P矩阵理论结果在通带内吻合很好,并与实验结果相符,验证了所提出等效电路模型的正确性。     

基于嵌入式Linux内核驱动的电气控制系统

在物联网环境下进行电气控制系统优化设计,提高电气自动化控制的品质和稳健性.提出一种基于嵌入式Linux内核驱动的电气控制系统设计方法,实现了水声智能传感电机的电气控制.首先进行了物联网环境下的水声智能传感电机系统的电气控制算法设计,通过基线漂移抑制,得到水声智能传感电机的电气控制内环模型参量整定模型.系统的硬件设计包括A/D采样电路、信号滤波电路、时钟控制电路、程序加载电路、接口电路等.采用嵌入式Linux内核驱动实现程序加载,实现系统的软件优化设计.仿真结果表明,该控制系统具有较好的输出匹配性能,鲁棒性较好,控制品质较高.     

静电感应晶闸管在阻断态时的SIT-BJT等效工作模型

提出了一种描述静电感应晶闸管在阻断态时的工作机理的SIT-BJT等效模型.在器件物理的基础上,分析得到的这个模型衔接了静电感应晶闸管的物理参数和结构参数,而且给出的数值分析和理论分析证明了这个模型的正确性.在该模型的基础上,讨论了势垒、阳极结的电势降落和电流的放大因子等电参数的变化.     

静电感应晶闸管在阻断态时的SIT-BJT等效工作模型

提出了一种描述静电感应晶闸管在阻断态时的工作机理的SIT-BJT等效模型.在器件物理的基础上,分析得到的这个模型衔接了静电感应晶闸管的物理参数和结构参数,而且给出的数值分析和理论分析证明了这个模型的正确性.在该模型的基础上,讨论了势垒、阳极结的电势降落和电流的放大因子等电参数的变化.     

Analysis of Millimeter Wave Varactor-Tuned Gunn Oscillator Stabilized with a Transmission Cavity

A novel circuit architecture which describes millimeter wave varactor-tuned Gunn oscillator stabilized with a transmission cavity has been proposed in this paper. A corresponding equivalent circuit model has been presented in order to study its performance characteristics. The circuit model consists of four parts which are varactor cavity, main cavity, transmission waveguide and transmission cavity. Based upon this model, electrical tuning characteristics have been studied at first. Mode jumping problems during electrical tuning process have been analyzed qualitatively. Moreover, quality factor and efficiency of the circuit model have been derived by virtue of relevant circuit parameters. The effects of some important circuit parameters affecting circuit performance parameters have been discussed. The circuit model can describe the circuit architecture accurately and effectively. This circuit architecture, which can generate signals exhibiting low frequency modulation noise, high frequency stabilization and electrical tunable characteristics, is applicable to various practical situations.     

Electrical and optical feedback in an InGaAs/InP light-amplifyingoptical switch (LAOS)

A circuit model for optical and electrical feedback has been developed to investigate the cause of negative differential resistance (NDR) switching in a series connected heterojunction phototransistor (HPT) light-emitting diode (LED) device. The model considers optical feedback from the light generated in the LED, electrical feedback from the holes thermally emitted over the LED cladding layer, nonlinear gain of the HPT, the Early effect, and leakage resistance. The analysis shows that either electrical or optical feedback can be the dominant cause for the NDR, depending upon their relative strengths. The NDR observed in the devices was caused primarily by electrical feedback since the optical feedback is weak. For low input power, avalanche breakdown appears to initiate the NDR in the devices although avalanching alone cannot cause NDR     

港口区域大型机械电气自动化控制模型设计

对港口区域大型机械电动自动化控制进行设计,是优化调度控制和监测港口区域工业生产的基础.提出一种港口区域大型机械电气自动化控制模型设计方法.根据高阶滑模控制算法得到电气自动化控制模型的非线性方程,选用SPIDNN网络作为三层向前的学习网络.在不影响港口区域大型机械电气控制的基础上对港口区域大型机械电流数据信号进行计算,完成港口区域大型机械电气自动化控制模型的设计.通过对港口区域大型机械电气自动化控制参数的干扰控制率进行计算,提高了港口区域大型机械电气自动化控制模型的抗干扰能力.实验结果表明,本文方法的抗干扰能力较强.