Piecewise-linear modeling of I-V characteristics with SPICE

This paper presents a technique for piecewise-linear modeling of arbitrary nonlinear I-V characteristics with SPICE. In particular, I-V characteristics (including those exhibiting negative resistance) that lend themselves to piecewise-linear approximation are easily modeled using six elemental building blocks; three for voltage-controlled I-V characteristics and three for current-controlled I-V characteristics. The elemental building blocks are implemented with resistor, diode, independent voltage source, and independent current source SPICE primitives. Two of the elemental building blocks use the ability of SPICE to accept negative values for the resistance and diode saturation current parameters. The technique is applied to model a unijunction transistor and a tunnel diode. Two negative resistance oscillator examples which use these models are included; a current-controlled negative resistance sinusoidal oscillator (unijunction transistor) and a voltage-controlled negative resistance relaxation oscillator (tunnel diode). These examples have been used to teach the fundamentals of negative resistance oscillators and nonlinear effects to sophomores and juniors     

Applications of SPICE simulation software to the study of reliability and availability in electrical engineering education

The effectiveness of SPICE in calculating probabilities, reliability, steady-state availability, and mean time to failure of repairable systems described by Markov models is demonstrated. Two examples are presented. The first example is a two-unit, warm standby, microcomputer system with self-reset function and repair facility. The second example is a robotic system comprising two identical robots and one safety system. In both cases, the results obtained using SPICE are compared with previously published results obtained using the Laplace transform method. Full SPICE listings are included.     

SPICE modeling of nonlinear memristive behavior

The recent discovery of the ‘modern’ memristor has drawn great attention of both academia and industry. Given their favorable performance merits, memristors are expected to play a fundamental role in electronic industry. Modeling of memristive devices is essential for circuit design, and a number of Simulation Program with Integrated Circuit Emphasis (SPICE) models have already been introduced. The common problem in most models is that there is no threshold consideration; hence, only a few address the nonlinear nature of the device. This paper aims to present a SPICE implementation of a threshold‐type switching model of a voltage‐controlled memristive device that attributes the switching effect to a tunneling distance modulation. Threshold‐type switching is closer to the actual behavior of most experimentally realizable memristive systems, and our modeling approach addresses the issue of programming thresholds. Both the netlist and the simple schematic are provided, thus making it easy to comprehend and ready to be used. Compared with other modeling solutions, it involves significantly low‐complexity operation under an unlimited set of frequencies, and its simulation results are in good qualitative and quantitative agreement with the theoretical formulation. The proposed model is used to simulate an antiserial memristive switch, proving that it can be efficiently introduced in complex memristive circuits. Copyright © 2013 John Wiley & Sons, Ltd.     

Advanced SPICE modeling of large power IGBT modules

An enhanced insulated gate bipolar transistor (IGBT) model based on the Kraus model with new derivations based on an extra parameter accounting for p-i-n injection was developed to allow simulation of both trench and DMOS IGBT structures. Temperature dependence was also implemented in the model. The model was validated against steady-state and transient measurements done on an 800-A 1.7-kV Dynex IGBT module at 25/spl deg/C and 125/spl deg/C. The Spice model has also shown excellent agreement with mixed mode MEDICI simulations. The Spice model also takes into account for the first time the parasitic thyristor effect allowing the dc and dynamic temperature-dependent latchup modeling of power modules as well as their temperature-dependent safe operating area.     

Application of SPICE simulation to study WDM and SCM systems using EDFAs with chirping

The authors have proposed an equivalent electrical circuit model of erbium-doped fiber amplifiers (EDFAs), including the chirping effect for teaching or studying the distortions and performance of lightwave transmission systems. Through the aid of a SPICE circuit simulator, its validity is demonstrated by analyzing the cross modulations of an eight-channel wavelength division multiplexing system. The intermodulations in an amplitude modulation-subcarrier multiplexing (SCM) system are demonstrated. The channel-number dependence of the composite second-order distortion in a 42-channel SCM system is shown, and its applications to analyze other systems are also discussed.     

Modeling and simulation of an electronically commutatedpermanent-magnet machine drive system using SPICE

This paper describes the design of high-efficiency, electronically commutated, permanent-magnet machine (ECPM) drives based on the finite-element/difference method, and the solution of the ensuing differential equations with the Simulation Program with Integrated Circuit Emphasis (SPICE). The permanent-magnet motor model includes the computation of load-dependent components of the motor-equivalent circuit (e.g., induced voltages and inductances). A new SPICE metal-oxide semiconductor field-effect transistor (MOSFET) model reflecting the reverse-recovery current phenomenon-which is very important for the design of variable-speed drives operating in the pulse-width-modulated (PWM) mode-is introduced. Results of this new model are compared with measurements. Since ECPMs lend themselves well to vehicle propulsion due to their inherent high efficiencies at light weight, it is desirable to have a very high output-power-to-weight ratio for such applications. In addition, high ECPM drive efficiencies are important for recovery of the braking energy     

Dynamic system reliability study modeling

This article extends conventional reliability modeling to a comprehensive modeling to cover system dynamic response and plant process response as the consequence of system component failures. The study results indicate the load outages from system dynamic response and process response cannot be neglected-they may have significant contributions to the system load outages. The example system study shows the conventional reliability modeling covers about 50% of total load outages. This modeling provides a more realistic approach. The modeling also considers the component failure rate adjustment for effects of component age and maintenance quality. The modelling, using accumulations of system segment contributions to load outages, is a practical approach for industrial systems. The results of reliability evaluation in terms of load outage indices, segment contributions, and overall system reliability indices, provide valuable information for plant management decision making with respect to return-of-investment in system reliability improvement projects. The reliability modeling can be coordinated with other system planning studies, such as system expansion and redesign, because these studies usually require system load flow, short circuit and transient stability analysis. These studies are usually involved in the evaluations of many alternatives. With the reliability evaluations added into the system planning study, the results will be more valuable for decision making among many alternatives     

Analysis and modeling of LC oscillator reliability

In this paper, MOS device degradations due to hot carrier and gate oxide breakdown are shown experimentally, and their effects on the NMOS LC oscillator have been evaluated analytically and through SpectreRF simulation. The reduction in transconductance of the differential pair transistors may cause the oscillation to cease. The amplitude of oscillation reduces as the equivalent tank resistance decreases due to the breakdown effect on the MOS varactor. The reduction of amplitude reduces the tank capacitances, and therefore shifts the frequency of oscillation and increases the oscillator phase noise. The tank amplitude of the oscillator is derived analytically. A closed-form expression for the average capacitance of the varactor that accounts for large-signal effects is presented. Finally, a set of guidelines to design an LC oscillator in reliability is presented.     

SEU reliability improvement due to source-side charge collection in the deep-submicron SRAM cell

The effect of technology scaling (0.5-0.09 /spl mu/m) on single event upset (SEU) phenomena is investigated using full two-dimensional device simulation. The SEU reliability parameters, such as critical charge (Q/sub crit/), feedback time (T/sub fd/) and linear energy transfer (LET), are estimated. For L/sub g/<0.18 /spl mu/m, the source node collects a significant fraction of radiation-induced charge resulting in an increase of LET, despite the lower critical charge at the sensitive drain node. The effect of striking location on LET confirms this finding.     

Learning about chaotic circuits with SPICE

A study of chaotic circuits is of educational value, both to students and to practicing engineers. Ten circuits that behave chaotically are simulated with SPICE, starting with simple abstract systems and preceding, via familiar circuits such as the monostable and the tuned amplifier, to a controlled DC-DC power converter. The examples show a variety of ways in which chaos can arise in analog electronic circuits. It is shown how SPICE may be used to produce Poincare sections of strange attractors, and bifurcation diagrams     

具备内部故障仿真能力的永磁同步发电机电磁暂态建模与仿真方法

对永磁同步发电机(PMSG)内部定子绕组故障的精确建模与仿真有助于设计有效的状态检测系统和控制保护策略。首先对PMSG内部故障特征进行分析和详细的数学推导,给出了适合电磁暂态(EMT)建模的状态空间形式的动态方程。进而提出了一种PMSG内部故障EMT建模与仿真方法,并推导出其等效电路。利用MATLAB对推导出的方程进行了数值计算迭代求解,并在PSCAD/EMTDC中搭建了PMSG测试模型,与数值计算结果进行分析和对比验证。分析结果表明,PMSG内部故障会在短路路径中产生较大的循环故障电流,但是从发电机外部特性很难判断是否发生内部故障。对比验证结果表明,所建立PMSG内部故障EMT模型可准确反映内部故障特征,验证了所提建模方法的正确性。     

应用模拟法进行发输电组合系统可靠性评估的研究

电力系统可靠性评估的方法可分为两大类解析法和模拟法。通过对发、输电组合系统可靠性的研究,建立了其评估模型,包括系统停运模型、负荷模型、运行调整策略模型、可靠性指标计算模型。并应用离散事件系统模拟法评估发输电组合系统的可靠性,给出了发输电组合系统可靠性评估模型流程图。     

A modified macro model approach for SPICE based simulation of single electron transistor

A new macro model of single electron transistor (SET) for SPICE based simulation of SET circuits is proposed. Two voltage controlled current sources and some scaling factors are incorporated in the existing model to derive our model. The V–I characteristics of the proposed SET is promising enough to be used as the basic element for designing circuits based on SETs. A comparison with the previous models establishes the fact that our model efficiently removes the drawbacks of the existing models. Our model also agrees well with the results obtained from popular SIMON simulator. To verify the accuracy, we have designed a SET inverter cell and investigated its characteristics. The work includes the effect of the parameters on the noise margin and voltage transfer characteristics of the inverter circuit. Further, to verify the applicability, a multi peak negative differential resistance circuit based on the proposed model is designed and simulated.     

Novel non‐linear macromodel suitable for SPICE simulation of analogue multipliers realized with bipolar and CMOS technologies

The purpose of this paper is to propose a simple and accurate non‐linear macromodel for analogue multipliers. The performance of the new macromodel is demonstrated by comparing the SPICE simulation results obtained with the device‐based models and with the macromodel. The most important result obtained in the frame of this work is the combination of accurate modelling with reduced computer time, thus providing the IC designer with the possibility of speeding up the simulation of large electronic systems. Copyright © 1999 John Wiley & Sons, Ltd.     

Transformer top-oil temperature modeling and simulation

Improving the utilization of transformers requires that the hot-spot temperatures and top-oil temperatures (TOTs) be predicted accurately. The authors' experimentation with various discretization schemes and models proved that many of the linear and nonlinear semiphysical and nonphysical models they were using to predict transformer TOT were correctly modeling the TOT behavior. Their experience convinced them that noisy input data and the absence of data on significant driving variables, not model deficiencies, were frustrating their attempts to reduce the prediction error further. In this paper, they discuss the body of research that led them to these conclusions     

Security modeling for power system reliability evaluation

This paper presents conceptual development, computation procedure and simulation results of the methodology for modeling security within reliability evaluation of power systems. The proposed approach takes into account activation of protection and automatic controls, local actions of operators, as well as centralized decisions taken by system operators. Transient stability, frequency variation during governor control, emergency and normal levels of line thermal protection, automatic generation control, overload rotation and economic dispatch are the main points of the developed procedure. It can be directly incorporated into the hybrid model for reliability evaluation of different operating states     

Chronological simulation for transmission reliability margin evaluation with time varying loads

This paper has as objective to assess the chronological variations in the Available Transfer Capability (ATC) caused by uncertainties associated with hourly load fluctuations and equipment availabilities. The system states resulting from these uncertainties are generated using the Monte Carlo Method with Sequential Simulation (MCMSS). The ATC for each generated state is evaluated through a linear optimal power flow based on the Interior-Point Method. These ATC values have been used to generate the probability distribution of the hourly ATC. This probability distribution enabled to estimate the Transmission Reliability Margin (TRM) for a specified risk level. The results, with a modified version of the IEEE Reliability test System, demonstrate that the time dependent uncertainties have a significant impact on the TRM.     

光伏电池建模及MPPT仿真研究

根据光伏电池数学模型,在Matlab/Simulink环境下建立光伏电池仿真模型,并在不同光照强度和环境温度条件下进行了仿真,结果表明,光伏电池的输出特性呈明显非线性并随环境温度和光照强度的变化而变化.此外,对该模型结合MPPT模块,实现对光伏电池最大功率点跟踪方面,提出了一种跟踪速度快、稳态精度高的改进粒子群算法.经仿真试验表明,该方法较传统方法具有明显的控制效果.