Efficient Transient Simulation Research Articles

POWER GRIDS ANALYSIS IN COMPRESSED KRYLOV-SUBSPACE METHODS

An improved method is proposed based on compressed and Krylov-subspace iterative approaches to perform efficient static and transient simulations for large-scale power grid circuits. It is implemented with CG and BiCGStab algorithms and an excellent result has been obtained. Extensive experimental results on large-scale power grid circuits show that the present method is over 200 times faster than SPICE3 and around 10–20 times faster than ICCG method in transient simulations. Furthermore, the presented algorithm saves the memory usage over 95% of SPICE3 and 75% of ICCG method, respectively while the accuracy is not compromised.

The power grid transient simulation in linear time based on 3-D alternating-direction-implicit method

The rising power consumption and clock frequency of very large scale integration technology demand robust and stable power delivery. Extensive transient simulations on large-scale power delivery structures are required to analyze power delivery fluctuation caused by dynamic IR drop and Ldi/dt drop as well as package and on-chip resonance. In this paper, we develop a novel and efficient transient simulation algorithm for the power distribution networks. Our algorithm, three-dimensional (3-D) transmission-line-modeling alternating-direction-implicit (TLM-ADI) method, first models the power delivery structure as 3-D transmission line shunt-node structure and transfers those equations to the telegraph equation. Finally, we solve it by the alternating direction implicit method. The 3-D TLM-ADI method, with linear runtime and memory requirement, is also unconditionally stable, which ensures that the time steps are not limited by any stability requirement. Extensive numerical simulation results show that the proposed algorithm is not only over 300 000 times faster than SPICE but also extremely memory saving and accurate.

Power grid transient simulation in linear time based on transmission-line-modeling alternating-direction-implicit method

The soaring clocking frequency and integration density demand robust and stable power delivery to support tens of millions of transistors switching. To ensure the design quality of power delivery, extensive transient power grid simulations need to be performed during the design process. However, the traditional circuit simulation engines are not scaled well for the complexity of power delivery. As a result, it often takes a long runtime and huge memory requirement to simulate a medium-sized power grid circuit. In this paper, the authors develop and present a new efficient transient simulation algorithm for power distribution. The proposed. algorithm, transmission-line-modeling alternating-direction-implicit (TLM-ADI), first models the power delivery structure as transmission line mesh structure, then solves the transient modified nodal analysis matrices by the alternating-direction-implicit method. The proposed algorithm, with linear runtime and memory requirement, is also unconditionally stable which ensures that the time-step is not limited by any stability requirement. Extensive experimental, results show that the proposed algorithm is not only orders of magnitude faster than SPICE but also extremely memory saving and accurate.

Envelope following method for the transient analysis of electrical circuits

An envelope following method (EFM) that allows efficient transient simulations of electrical circuits is here presented. Its mathematical and electrical bases are considered and the influence of some general properties, such as stability and truncation error of integration methods employed by EFM, are studied. Furthermore, we present a new state variable prediction algorithm that improves previously reported ones, since it better adapts to fast dynamics of the solution. A set of power switching circuits is employed as a benchmark and numerical results of our algorithm are compared to those of conventional integration and of previous EFM versions. Remarkable results are obtained in the electrothermal simulation of power converters where the efficiency gain rises up to some magnitude orders with respect to conventional integration.

Dynamic simulation of free surfaces in capillaries with the finite element method

The mathematical formulation of the dynamics of free liquid surfaces including the effects of surface tension is governed by a non-linear system of elliptic differential equations. The major difficulty of getting unique closed solutions only in trivial cases is overcome by numerical methods. This paper considers transient simulations of liquid–gas menisci in vertical capillary tubes and gaps in the presence of gravity. Therefore the CFD code FIDAP 7.52 based on the Galerkin finite element method (FEM) is used. Calculations using the free surface model are presented for a variety of contact angles and cross-sections with experimental and theoretical verification. The liquid column oscillations are compared for numerical accuracy with a mechanical mathematical model, and the sensitivity with respect to the node density is investigated. The efficiency of the numerical treatment of geometric non-trivial problems is demonstrated by a prismatic capillary. Present restrictions limiting efficient transient simulations with irregularly shaped calculational domains are stated. © 1998 John Wiley & Sons, Ltd.

Efficient transient simulation of high-speed interconnects characterized by sampled data

In this paper, we present an algorithm for efficient simulation of high-speed interconnects characterized by sampled data. The method constructs pole-zero models of arbitrary interconnects using robust rational approximations of the measured or simulated scattering parameters. In order to obtain accurate interpolations of the data over a wide frequency range, a set of powerful techniques is applied to deal with the resulting ill-conditioned Vandermonde-like approximation matrices. By utilizing the analytic properties of the scattering parameters, the algorithm efficiently generates multiport pole-residue models. The models are combined with the lumped/distributed components for direct time- or frequency-domain simulations. The method can easily be implemented into conventional simulators such as simulation program with integrated circuit emphasis (SPICE) and advanced statistical analysis program (ASTAP) or reduced-order modeling techniques such as asymptotic waveform evaluation (AWE), complex frequency hopping (CFH), and Padd approximation via Lancros Process (PVL) for transient simulation of high-speed interconnect networks. Examples of linear and nonlinear networks are given to demonstrate the validity and accuracy of the method.

Efficient transient simulation of embedded subnetworks characterized by S-parameters in the presence of nonlinear elements

This paper presents an efficient technique for transient simulation of linear subnetworks characterized by S-parameters in the presence of nonlinear components. The proposed method is based on the recently developed model-reduction technique, complex frequency hopping. A new algorithm for computing the moments of S-parameter-based subnetworks is presented. The proposed method is suitable for simulating large number of S-parameter-based subnetworks in a general circuit environment consisting of lumped/distributed elements and nonlinear devices.

Simplified transient simulation of two phase flow using quasi-equilibrium momentum balances

Transient simulations of two phase gas-liquid flow in pipes require considerable computational efforts. Available commercial Codes that were developed, or are being developed at the present, use either the two fluid model or the drift flux model. These models implement continuity and momentum transient equations. In many occasions, in particular for the oil and gas industry, the transient response is usually relatively slow. Thus, it is suggested here to use quasi equilibrium momentum equations for the liquid and the gas together with transient continuity equations. This procedure results in a simplified numerical algorithm which can be used as an efficient transient simulator.

Correction to "Efficient Transient Simulation of Lossy Packaging Interconnects Using Moment-Matching"

Correction to "Efficient Transient Simulation of Lossy Packaging Interconnects Using Moment-Matching"

Transient simulation of integrated circuits in the charge-voltage plane

Transient simulation has traditionally been performed in the current-voltage plane (with current and voltage as variables) for verification of integrated circuits and systems. This paper introduces techniques for efficient and accurate transient simulation in the charge-voltage plane (with charge and voltage as variables). For integrated circuits, both simulation cost and overhead to increase accuracy are drastically reduced by performing simulations in the charge-voltage plane. Adaptively controlled explicit simulation in charge-voltage plane is used to demonstrate the feasibility of the approach. Solution of circuit equations in the charge-voltage plane is 10-20 times more efficient than in the current-voltage plane. Furthermore, simulation accuracy can be increased at an incremental cost. As a result, ACES in the charge-voltage plane provides speedups of 300/spl times/-5000/spl times/ or more over traditional circuit simulators with little or no loss in circuit timing accuracy, and simulates circuits containing more than million transistors.