A fast power loss calculation method for long real time thermal simulation of IGBT modules for a three‐phase inverter system

A fast power losses calculation method for long real time thermal simulation of IGBT module for a three‐phase inverter system is presented in this paper. The speed‐up is obtained by simplifying the representation of the three‐phase inverter at the system modelling stage. This allows the inverter system to be simulated predicting the effective voltages and currents whilst using large time‐step. An average power losses is calculated during each clock period, using a pre‐defined look‐up table, which stores the switching and on‐state losses generated by either direct measurement or automatically based upon compact models for the semiconductor devices. This simulation methodology brings together accurate models of the electrical systems performance, state of the art‐device compact models and a realistic simulation of the thermal performance in a usable period of CPU time and is suitable for a long real time thermal simulation of inverter power devices with arbitrary load. Thermal simulation results show that with the same IGBT characteristics applied, the proposed model can give the almost same thermal performance compared to the full physically based device modelling approach. Copyright © 2006 John Wiley & Sons, Ltd.     

Transient tolerance analysis of power cables thermal dynamic by interval mathematic

The safeguard of power equipments is assuming a major role in the deregulated electricity market, where a malfunctioning power system could be responsible for serious damages to a large number of system operators having access to the shared energy resource.In this context thermal monitoring of power cables represents a key issue in evaluating the risks associated with a given load management policy especially during emergency conditions. In particular this demands for reliable assessment models that should be able to predict the transient thermal behaviour when the load exceeds the nameplate value.In this connection the application of both simplified and detailed power cable thermal models is often complicated by the presence of uncertainties affecting the tolerances of the input data. The effect of these uncertainties could influence the final solution to a considerable extent.A comprehensive tolerance analysis is therefore required in order to incorporate the effect of data uncertainties into the thermal modelling process.To address this problem, in the paper the employment of interval mathematic is proposed. Several numerical results are presented and discussed in order to assess the effectiveness of the proposed methodology which offer a rough qualitative insight of the solution in a very short time, comparable to the time required for a deterministic numerical simulation.     

适用于器件级到系统级热仿真的IGBT传热模型

提出一种基于器件到系统的等级与传热网络结构本身的多时间尺度特征建立绝缘栅双极型晶闸管(IGBT)传热模型的建模方法。基于热传导理论和经典Cauer传热RC网络结构,建立IGBT传热网络结构模型,查明单层与多层热网络结构的结温运行规律以及简化标准与方法。在此基础上,以器件到系统对IGBT传热模型的不同需求为主线,以器件封装结构各层时间常数的不同时间尺度为切入点,建立适用于器件级到系统级热仿真的IGBT传热模型。仿真与实验结果验证了模型的正确性与高效性。所建立的IGBT传热模型对于查明IGBT器件的传热网络结构特征与结温运行规律,实现电力电子器件到系统的独立与联合仿真具有一定的理论意义和应用价值。     

基于OpenDSS的智能配电网仿真与模拟平台及其应用

OpenDSS仿真系统为含分布式电源及储能装置的配电网提供仿真分析和规划研究平台,并为智能配电网提供一个开放共享的研究平台.从建模方法、仿真功能和用户自定义扩展应用3个方面介绍了OpenDSS的特点和优势.在建模方法上,该平台考虑了配电网的不对称特性,并提供了丰富的配电网控制模型;在仿真功能上,提供了快速潮流计算功能,并开发了一系列仿真方法;在用户自定义扩展上,基于COM接口,实现了OpenDSS和其他仿真软件的互动.针对上述功能和特点,以及给出的应用实例,希望能够对推动智能配电网快速仿真与模拟技术在中国的应用与发展起到一定的作用.     

Comparison of different methods used in integral codes to model coagulation of aerosols

The methods for calculating coagulation of particles in the carrying phase that are used in the integral codes SOCRAT, ASTEC, and MELCOR, as well as the Hounslow and Jacobson methods used to model aerosol processes in the chemical industry and in atmospheric investigations are compared on test problems and against experimental results in terms of their effectiveness and accuracy. It is shown that all methods are characterized by a significant error in modeling the distribution function for micrometer particles if calculations are performed using rather “coarse” spectra of particle sizes, namely, when the ratio of the volumes of particles from neighboring fractions is equal to or greater than two. With reference to the problems considered, the Hounslow method and the method applied in the aerosol module used in the ASTEC code are the most efficient ones for carrying out calculations.     

基于传热动力学作用特征的IGBT结温预测数学模型

提出一种基于传热动力学作用特征建立绝缘栅双极型晶体管(IGBT)结温预测模型的建模方法。针对目前IGBT结温预测模型无法灵活应用于多时间尺度仿真与快速计算模式的问题,通过将简单(阶跃)信号下得到的动力学作用分量应用于复杂(PWM)信号下,建立IGBT结温预测数学模型。基于经典Cauer传热RC网络结构,建立针对阶跃功率输入信号的IGBT结温预测数学模型。提出采用自然解耦的方法,对IGBT传热动力学特性进行研究,建立传热动力学作用分量的准确表征。在此基础上,采用自然解耦与精确补偿的方法,建立针对PWM脉冲功率输入信号的IGBT瞬态结温预测数学模型。仿真与实验结果验证了模型的正确性与准确性。所建IGBT结温预测数学模型对于查明IGBT器件的传热动力学作用机理,实现结温的快速有效仿真与计算,建立IGBT传热多时间尺度数学模型具有重要的理论意义和应用价值。     

变电站轮询式通信网络的MATLAB仿真研究

本文根据变电站通信网络的特点,提出了使用离散事件仿真的方法研究网络性能的新思路。以此为指导,本文以变电站内部轮询网络为例,采用队列表示方法对该通信网络进行抽象以便明确研究目标,然后使用MATLAB的SIMULINK软件包对通信网络完成了图形化的仿真建模工作,针对所得的仿真结果进行分析比较,得出了一些较有意义的结论。最后,本文将软件仿真结果和排队论指导结果作了对比,证明了本仿真模型和实际系统是相吻合的。     

基于Matlab的大型火电机组一次调频特性仿真

大型发电机组的一次调频对保持电力系统频率稳定、防止因突发的负荷变动及发电机跳闸等功率突变造成的频率波动,引发连锁反应至关重要。为研究大型火电机组的一次调频特性建立了基于Matlab Simulink工具的仿真平台,并给出了利用此平台进行大型火电机组一次调频特性和影响因素研究的结果。该平台为大型火电机组机炉协调运行方式和参数整定等研究提供了定量分析手段。     

A three-terminal piecewise-linear modelling approach to dc analysis of transistor circuits

The simulation of electronic circuits by computer has become an important part of present-day circuit analysis and design, especially in the area of integrated circuit design. One of the goals in computer simulation of integrated circuits is to have a program ‘package’ for which the input consists of chip fabrication data (mask dimensions, impurity profiles, material data such as carrier lifetimes) and the output displays the complete circuit response. This requires both an efficient modelling approach and a fast circuit analysis method. In this paper a simulation method is described which generates dc responses (in the form of operating points or transfer characteristics) of transistor circuits directly from physical parameter data. The basis of the method is a two-dimensional piecewise-linear approach to the dc modelling of bipolar transistors. The model is directly used in a piecewise-linear circuit analysis program to simulate the dc response of a given circuit.     

Discrete Green's functions and hybrid modelling of thermal and particle diffusion

This paper provides details of a widely applicable technique of hybrid modelling of thermal and particle diffusion which can help to reduce computational load in explicit formulation. The undesirable effects of artificial boundaries, which are introduced when a simulation is truncated or when an expanding mesh is used, can be eliminated by the use of discrete Green's functions. The technique can also be applied to problems involving infinite or near-infinite domains or problems where a complex thermal region is embedded within a larger, more simply described domain.     

永磁同步发电机电磁暂态等效建模方法及稳定性分析

嵌套同时快速求解(nested fast and simultaneous solution, NFSS)算法通过消去电路节点可以显著提高仿真速度。然而,商业仿真软件提供的永磁同步发电机(permanent magnet synchronous generator, PMSG)模型无法获取等效电路,限制了该算法在海上风电中的应用。针对上述问题,提出了PMSG电磁暂态(electro-magnetic transient, EMT)等效建模方法,并分析了建模方法的稳定性。首先,将PMSG数学模型离散化,得到用三相受控电流源表示的等效电路及接口方法,给出PMSG的控制模式和等效模型求解流程。并结合实际PMSG参数取值,分析了等效建模方法的稳定性。最后,在PSCAD/EMTDC中搭建了PMSG详细模型和等效模型进行仿真精度对比及稳定性验证,结果表明,所提模型及稳定性分析具有较好的正确性,为NFSS算法在海上风电中的应用提供了模型基础,也为发电机参数的选取提供了约束条件。     

基于MATLAB-SIMULINK软件风电场建模仿真研究

给出了MATLAB-SIMULINK软件的自定义模型,并将之结合PSS／E仿真软件对发电机和励磁模型进行动态仿真设置,通过将风电场接入电网的模型仿真,结果表明,风电场对系统运行造成的主要影响是风电场并网运行引起的系统电压频率的波动和系统发生故障时风电场表现出不同于传统的火电厂的运行特性,故障时系统对风电场的作用影响系统节点电压和系统频率等。     

Immitance data modelling via linear interpolation techniques: A classical circuit theory approach

With the advancement of the manufacturing technologies to produce new generation analog/digital communication systems, immitance data modelling has gained renewed importance in the literature. Specifically, models are utilized for behaviour characterization, simulation of physical devices or to design sub‐systems with active and passive solid‐state devices. Therefore, in this paper, new computer aided tools are presented to model one port immitance data by means of linear interpolation techniques. The basic philosophy of the new modelling tools is based on the numerical decomposition of the immitance data into its minimum and Foster parts. Computer algorithms are presented to model the minimum and the Foster parts of the given immitance data. Implementations of these algorithms are exhibited by means of examples. Depending on the application, modelling tools based on linear interpolation techniques may present ‘computational and practical’ advantages over the existing interpolation techniques, non‐linear curve fittings or regression methods. It is expected that the new modelling tools will be utilized to provide initial circuit topologies to the commercially available analysis/simulation and design packages. Copyright © 2004 John Wiley & Sons, Ltd.     

大型单轴燃气轮发电机组主控制系统功率调节的设计策略

该文以燃气轮发电机组的综合法动力学模型为基础,对燃气轮发电机组主控制系统的设计方案作了深入的分析和研究,包括以综合法模型为基础制定了并网后机组的功率控制策略,给出了控制器参数的确定及修正方法,并通过全数字仿真运行实验,分析了所得到的功率调节算法的工作原理和效用,通过消化吸收国外技术,提出了自己的有关燃气轮机控制系统设计的理论。     

A new general method to model signal timing of E/D NMOS logic

A new general modelling method for E/D NMOS logic is proposed and applied to the case of inverters. In this model, non-linear device currents in the large-signal equivalent circuit are reformulated by the curve-fitting technique. Then output voltage wave-forms are analytically solved region by region from the equivalent circuit. From the derived formulae, the rise/fall time and delay time can be calculated. Wide-range comparisons with SPICE simulation results were performed to verify the accuracy and the general applicability of the developed model. Two examples are given to demonstrate the applications of the developed timing model to timing analysis. It is shown that the model has a good accuracy for E/D inverters with a wide range of beta ratios, gate sizes, capacitive loads, input voltage wave-forms and device parameters. Moreover, the required CPU time and memory are small. These make the proposed modelling method an interesting approach to model E/D NMOS gates for CAD applications.     

An innovative solution for AC drive operation during voltage sags using a custom power device

The paper describes an innovative technique for modelling and control of a dynamic voltage restorer (DVR) model for use within distribution systems and presents a design method based on the DVR to increase the reliability of a pulse-width modulated drive system due to AC power line sags. Validation is achieved by comparing simulation results of the modelling method of this paper with results from previous performance tests for actual system scenarios. Received: 2 November 2001/Accepted: 13 December 2001     

大型空冷汽轮发电机转子温度场数值模拟

随着空冷汽轮发电机容量增加，其组件的可靠性依赖于冷却系统散热能力。因而，了解关于发电机中各空气区域内的速度及温度分布是非常重要的。为了能够数值模拟出较详细和较准确的大型汽轮发电机转子温升分布，该文以150MW空冷汽轮发电机转子作为研究对象，建立了模拟转子本体及通风道内空气的传热及紊流流动二维数学模型及边界条件，并利用CFD原理，采用有限体积法进行求解，得出了转子周期截面较准确的不对称温度分布。并将计算结果与实验测量结果相比较，证明计算结果较准确。分析了副槽入口风速等参数对转子温度分布的影响。结论对汽轮发电机转子通风道优化设计及转子安全运行具有指导意义。     

Analysis and design of voltage‐controlled current sources for a grounded load

The paper presents the structure and the principle of operation of the ‘improved’ Howland current pumps (or voltage‐controlled current sources (VCCSs) for a grounded load). In particular, under review is the VCCS employing power operational amplifier (op amp) and the VCCS using low power op amp and an additional power transistor, extending working dynamic range. On the basis of analysis of the operational principle, the equations for transfer functions of both circuits and formulas for the related dynamic electrical parameters are obtained. Moreover, using these formulas, a design procedure is developed, and recommendations for simulation modelling are given. The efficiency of the proposed procedure is verified by simulation modelling and experimental testing of sample electronic circuits of VCCSs. Copyright © 2013 John Wiley & Sons, Ltd.     

石门300MW机组锅炉热态模化方法探讨

本文就大型机组锅炉燃烧过程的热态模化方法进行了探讨，介绍了热态模化的原理和基本方法，并根据此方法在我所大型煤粉燃烧试验炉（四角切向燃烧炉）上针对石门电厂３００ＭＷ机组锅炉可能燃用的混煤，就着火、稳燃、燃烬和结渣等问题进行了热态模化试验。为锅炉的设计和运行提供了技术依据。     

Development of an electrothermal simulation tool for integrated circuits: Application to a two-transistor circuit

In this paper a methodology for performing electrothermal analyses on integrated circuits is introduced. Using the relaxation method, standard electrical and thermal simulators, which are often used in the design process, are coupled through an efficient interface program. The simulator is capable of performing steady-state and transient analysis at device and chip levels. A variable-time-step technique has been implemented to reduce the computational time for a given set of computational resources. The simulator has been validated on different structures such as the bipolar junction transistor to predict the temperature distribution and the device performance in an amplifier circuit and an integrated current-mirror circuit. The simulation results are compared to experimental results to verify the performance of the electrothermal simulator and the accuracy of the thermal model. Simulation results demonstrate that the approach is suitable to model the thermal effects of integrated circuits in a more time-efficient, accurate and user-friendly fashion.