Fast decoupled simulation of large power electronic systems usingnew two-port companion link models

Algorithms of novel two-port companion link models for fast decoupled simulation are presented. The link models enable a large circuit to be broken down into many small subcircuits for easy circuit formulation and fast simulation. The proposed link algorithms are demonstrated in a converter-fed HVDC transmission system with a transmission-line length equivalent to 1000 km. Simulation and experimental results from a laboratory setup have confirmed the validity of the link models. Proposed simulations are also found to be faster and more accurate than PSpice simulations in the example     

Decoupled simulation of DC-linked power electronic systems usingtransmission-line links

This paper describes the application of the transmission-line modeling (TLM) method to the decoupled simulation of DC linked power electronic systems. Stiff capacitively or inductively smoothed DC links in power electronic systems can be modeled as two-port transmission-line links using the TLM method. The TLM links enable the circuits connected by the links to be decoupled and simulated as individual circuits, resulting in smaller system matrices, possibility of parallel computation and reduction in computing time. Interaction between these linked circuits can be realised by exchanging the incident pulses at both ends of the transmission-line links. Computer simulations of an AC to DC converter used in a laboratory confirms the simplicity of the TLM decoupled simulation approach     

典型电力电子电路仿真的研究

电力电子技术的关键知识点很多,电路结构变换复杂,但在应用中,典型的电路最为常见,分析好典型电路也就掌握了电力电子技术的核心内容。文中给出了设计思路和仿真方法,详细分析三个经典的电力电子电路,将电路中关键的变量仿真出来,并最终给出了实际的仿真效果图。     

Fast simulation of multistage power electronic systems with widelyseparated operating frequencies

This paper presents a fast and efficient way of simulating multistage power electronic circuits with different stages operating at widely separated frequencies, using the transmission-line modeling (TLM) technique. A multistage circuit can be modeled as several smaller subcircuits, which can then be simulated individually with different time steps according to their circuit time constants. Energy exchange between linked subcircuits are made possible via the use of a new TLM stub link conversion technique and improved TLM link algorithms. The proposed technique has been tested successfully in a simulation of a switched-mode power supply. Simulation results confirm that the new approach can greatly reduce the computing time of the simulation when compared with conventional TLM simulation methods. A reduction of about two-thirds of the computing time has been achieved in the simulation of a three-stage switched-mode power supply     

A new algorithm for rapid tracking of approximate maximum power point in photovoltaic systems

This paper presents a new algorithm for tracking maximum power point in photovoltaic systems. This is a fast tracking algorithm, where an initial approximation of maximum power point is (MPP) quickly achieved using a variable step-size. Subsequently, the exact maximum power point can be targeted using any conventional method like the hill-climbing or incremental conductance method. Thus, the drawback of a fixed small step-size over the entire tracking range is removed, resulting in reduced number of iterations and much faster tracking compared to conventional methods. The strength of the algorithm comes from the fact that instead of tracking power, which does not have a one-to-one relationship with duty cycle, it tracks an intermediate variable /spl beta/, which has a monotonically increasing, one-to-one relationship. The algorithm has been verified on a photovoltaic system modeled in Matlab-Simulink software. The algorithm significantly improves the efficiency during the tracking phase as compared to a conventional algorithm. It is especially suitable for fast changing environmental conditions. The proposed algorithm can be implemented on any fast controller such as the digital signal processor. All the details of this study are presented.     

A new control philosophy for power electronic converters asfictitious power compensators

A new philosophy utilizing both thyristor-controlled reactive sources (TCR) and dynamic power filters (DPF) is proposed for applications in fictitious power compensation. The necessary network parameters for the control loops are calculated from digital time-domain, cross correlation signal processing techniques implemented with the aid of a microcomputer. Practical results that illustrate this control philosophy were obtained for a 15 kVA three-phase dynamic power filter     

A review of hydrodynamic and energy-transport models for semiconductor device simulation

Since Stratton published his famous paper four decades ago, various transport models have been proposed which account for the average carrier energy or temperature in one way or another. The need for such transport models arose because the traditionally used drift-diffusion model cannot capture nonlocal effects which gained increasing importance in modern miniaturized semiconductor devices. In the derivation of these models from Boltzmann's transport equation, several assumptions have to be made in order to obtain a tractable equation set. Although these assumptions may differ significantly, the resulting final models show various similarities, which has frequently led to confusion. We give a detailed review on this subject, highlighting the differences and similarities between the models, and we shed some light on the critical issues associated with higher order transport models.     

A new recombination model for device simulation including tunneling

A recombination model for device simulation that includes both trap-assisted tunneling (under forward and reverse bias) and band-to-band tunneling (Zener tunneling) is presented. The model is formulated in terms of analytical functions of local variables, which makes it easy to implement in a numerical device simulator. The trap-assisted tunneling effect is described by an expression that for weak electric fields reduces to the conventional Shockley-Read-Hall (SRH) expression for recombination via traps. Compared to the conventional SRH expression, the model has one extra physical parameter, the effective mass m*. For m*=0.25 m₀ the model correctly describes the experimental observations associated with tunneling. The band-to-band tunneling contribution is found to be important at room temperature for electric fields larger than 7×10⁵ V/cm. For dopant concentrations above 5×10¹⁷ cm^-3 or, equivalently, for breakdown voltages below approximately 5 V, the reverse characteristics are dominated by band-to-band tunneling     

A new quantum effect model for practical device simulation

An increase in the complexity of VLSI design, especially in process integration, is leading to increased demands for technology CAD (TCAD). The quantum mechanical (QM) effect becomes very important with an increase in the channel impurity concentration. Several models for the QM effect have been proposed. However, it has been reported that these models had some problems. In this paper, a new QM model for a conventional device simulator is proposed. Applications of this model to NMOS and PMOS including the buried-channel are examined     

A new algorithm for power system state estimation

A new algorithm to estimate the state of a power system is presented. It completely overcomes the convergence problems associated with the WLS algorithm and has excellent convergence properties. It leads to an estimate which is very close to the true value of the state vector.     

Physics-of-failure assessment methodology for power electronic systems

Driven by consumer markets and industrial needs, power electronic systems are operating at higher power densities, in smaller packages and in more exotic environments. As these trends continue, ensuring long-term operation in harsher conditions requires accurate reliability prediction models, most viably obtained through Physics-of-Failure (PoF) methodologies. This paper introduces a PoF-based system-level reliability assessment procedure in which the dominant failure mechanisms are identified for three primary subsystems: the power module, DC-link capacitors and the control circuitry. This report outlines the dominant failure modes and mechanisms for each subsystem and provides examples of how to improve subsystem reliability based upon the described assessment methodology. A case study is also presented in which the solder interconnect reliability of the gate-driver board in a mid-range variable frequency drive (VFD) was assessed.     

Behavior-mode simulation of power electronic circuits

In this paper, a systematic approach for the behavior-mode simulation of power electronic circuits is presented. To solve the problem of switch-state detection in behavior-mode simulation, a simple-to-implement reinitialization technique is introduced. Furthermore, the issue of time-step selection is discussed. It is illustrated through examples that behavior-mode simulation complements the detailed-mode simulation and enhances the efficiency of the computer-aided analysis and design of power electronic circuits     

一种病态线性系统求解的新算法

本文提出了一种病态线性系统求解的新算法,该算法将原线性系统求解的问题转化为极小值点的最优化问题,借助不对分寻优法进行迭代求解,并结合引入的伪误差来解决当方程组阶数非常大时出现的误差积累问题。文末算例实验表明,本文算法对于良态线性系统、病态线性系统均有较好的求解效果。该算法为病态线性系统利用计算机迭代求解提供了直接的参考方法。     

A new algorithm for performance analysis of communication systems

An algorithm is proposed for generating in order the most likely states of a probabilistic system, thus allowing a more-rapid procedure than previously available for analyzing the performance of communication networks with stochastically failing components. The algorithm improves the algorithm reported by Y. F. Lam and V.O.K. Li (ibid., vol.COM-34, no.5, p.496-7, May 1986), in terms of both storage requirements and execution efficiency     

Modeling and simulation of power electronic converters

This paper reviews some of the major approaches to modeling and simulation in power electronics, and provides references that can serve as a starting point for the extensive literature on the subject. The major focus of the paper is on averaged models of various kinds, but sampled-data models are also introduced. The importance of hierarchical modeling and simulation is emphasized     

A new power control function for multirate DS-CDMA systems

This paper proposes a closed-form power control function for the reverse link of a multirate single chip-rate variable processing gain DS-CDMA system in a mobile radio environment that assumes a Rayleigh fading channel with log-normal shadowing and path loss. A closed-form open-loop power control function based on a newly defined traffic exponent is proposed, and nonlinear programming is used to perform the optimization. In addition, a user model that allows users to dynamically switch traffic rates for different connection applications is implemented. Results obtained using random chip sequences demonstrate improvement in the system capacity with the new power control function compared to the conventional power control function. Furthermore, the proposed function also simplifies the power control processing     

OFDM系统中基于SLM降低PAPR的新算法

SLM(选择性映射)算法能解决OFDM(正交频分复用)系统中的高PAPR(峰均功率比)问题,但是基本的SLM算法具有较高的计算复杂度。提出一种G-SLM(分组SLM)算法,该算法通过将输入信号进行分组的方式来降低其与相位因子结合时的算法复杂度。仿真结果表明,该算法不但保持了较低的算法复杂度,同时又有效地降低了PAPR。     

A new modeling and simulation CAD package for power converterdesign

The PECADS software CAD package is a powerful PC-based tool, used in the study and design of power electronics, in which a new real structure simulation concept has been developed. The system has the capability for steady-state simulation, which allows topology election, FFT analysis, etc., and for slow down real-time simulation, which allows system identification, digital regulator synthesis, and closed-loop system simulation. The full PECADS package also includes power semiconductors, protection sizing (using the magnitudes simulation capability), and a dedicated expert system that generates the most adequate switching pattern sequence for every application. The total system is fully open to expansion or improvement