Abstract—This paper formalizes a family of logic gate characterization methods that result in Mul... more Abstract—This paper formalizes a family of logic gate characterization methods that result in Multiple Voltage Threshold Models (MVTM). This modeling technique includes the existing industry standards, such as CCS and ECSM driver models as special cases. Based on this general model, the paper introduces a novel analysis algorithm for computing the output waveform of the driver gate loaded by an arbitrary interconnect circuit. The analysis technique relies solely on the primary MVTM characterization data and, unlike competing solutions, it does not require the explicit instantiation of controlled current source models, thus bypassing an intermediate modeling step. As a consequence, the method is more accurate, efficient and more general than the emerging industry standards. The theoretical results are validated by detailed simulations and through full chip timing analysis. I.
In this paper, we present a flexible conjugate gradient method that is tailored to the solution o... more In this paper, we present a flexible conjugate gradient method that is tailored to the solution of the truly large-scale linear systems arising in VLSI power grid analysis. The algorithm allows changing preconditioners and sparsification of the search direction at each iteration. As a consequence, this variant of the conjugate gradient algorithm becomes compatible with implementations that avoid the modeling and representation of numerically irrelevant portions of the problem, and take natural advantage of the local and sparse nature of the solutions. The paper presents the flexible conjugate gradient algorithm in detail and explores strategies for preconditioning and sparsification. The algorithm is applied to a number of realistic power grid examples.
2015 IEEE International Conference on Smart Grid Communications (SmartGridComm)
Power grids reliability and security are influenced by transient behaviors of various power syste... more Power grids reliability and security are influenced by transient behaviors of various power system components. However, analyzing these transient behaviors needs to estimate millions of time-domain state variables with high computational efficiency. Most of the existing simulators are not based on parallel software platforms which have been proven to be powerful in many other applications. They are thus incapable of simulating transient behaviors of large-scale power systems efficiently. The lack of powerful dynamic simulation tool has become a major bottleneck towards the smarterization of power grids. Inventing a software based novel fully parallel topology of power systems, we propose a multi-threading based parallel simulator for transient behavior analysis in this paper. The accuracy and efficiency of the proposed simulator has been evaluated on IEEE and Polish standard bus systems, against the state-of-the-art open source software package (MatDyn). The results show that the runtime of the proposed simulator attains up to 80.49 ×speedup compared with MatDyn on 12-thread CPUs.
IEEE International Symposium on Circuits and Systems, 1996
Abstract-We describe the application of the PVL algorithm to the small-signal analysis of circuit... more Abstract-We describe the application of the PVL algorithm to the small-signal analysis of circuits, including sensitivity computa-tions. The PVL algorithm is based on the efficient computation of the Pad6 approximation of the network transfer function via the Lanczos process. The ...
2006 Ieee International Symposium on Circuits and Systems, 2006
Abstract The simulation of circuits containing silicon-on-insulator (SOI) transistors encounters ... more Abstract The simulation of circuits containing silicon-on-insulator (SOI) transistors encounters specific difficulties mainly due to the presence of the insulated body nodes, ie, connected by high impedance connections with the rest of the circuit. These high ...
2011 IEEE International Symposium of Circuits and Systems (ISCAS), 2011
ABSTRACT This paper described a model-order reduction (MOR) method based on a novel pure-nodal an... more ABSTRACT This paper described a model-order reduction (MOR) method based on a novel pure-nodal analysis formulation (PNA) which permits the use of symmetric, positive-definite Cholesky solvers for all circuit topologies. Moreover, frequently occurring special cases, e.g., inductor-resistor tree structures result in particular types of matrices that are solved by an even faster linear time algorithm. The model order reduction algorithms also uses symmetric-Lanczos iteration and non- standard inner-products for generating the Krylov subspace basis. Its efficiency is supported by a wide range of industrial examples.
2012 IEEE Power and Energy Society General Meeting, 2012
ABSTRACT This paper introduces a new paradigm for solving AC Power Flow (ACPF) and AC Optimal Pow... more ABSTRACT This paper introduces a new paradigm for solving AC Power Flow (ACPF) and AC Optimal Power Flow (ACOPF) with improved convergence robustness. This approach exploits the globally convergent properties of continuation methods. Continuation methods achieve robustness by generating a sequence of nonlinear problems and repeatedly and consistently providing good initial guesses for locally convergent nonlinear solvers such as Newton-Raphson. The Homotopy implemented in this paper, (referred to as Power Flow Homotopy, PFH), is formulated in a way that gradually transforms the “easy” DC into the “difficult” AC Power Flow. Successive changes of the homotopy parameter modify the system of equations from fully linear and convex DC into non-linear and non-convex AC (optimal) power flow. As a result, the AC solution is obtained with increased robustness and multiple AC power flow solutions can also be detected. Similarly, Optimal Power Flow Homotopy (OPFH) is defined for solving AC Optimal Power Flow, by gradually transforming the convex DC OPF problem. Simulation results provide a comparison between the simple Newton-Raphson method and PFH in terms of performance and quality of detected solution. Comparisons are also performed between the Interior-Point method and OPFH.
Abstract—This paper formalizes a family of logic gate characterization methods that result in Mul... more Abstract—This paper formalizes a family of logic gate characterization methods that result in Multiple Voltage Threshold Models (MVTM). This modeling technique includes the existing industry standards, such as CCS and ECSM driver models as special cases. Based on this general model, the paper introduces a novel analysis algorithm for computing the output waveform of the driver gate loaded by an arbitrary interconnect circuit. The analysis technique relies solely on the primary MVTM characterization data and, unlike competing solutions, it does not require the explicit instantiation of controlled current source models, thus bypassing an intermediate modeling step. As a consequence, the method is more accurate, efficient and more general than the emerging industry standards. The theoretical results are validated by detailed simulations and through full chip timing analysis. I.
In this paper, we present a flexible conjugate gradient method that is tailored to the solution o... more In this paper, we present a flexible conjugate gradient method that is tailored to the solution of the truly large-scale linear systems arising in VLSI power grid analysis. The algorithm allows changing preconditioners and sparsification of the search direction at each iteration. As a consequence, this variant of the conjugate gradient algorithm becomes compatible with implementations that avoid the modeling and representation of numerically irrelevant portions of the problem, and take natural advantage of the local and sparse nature of the solutions. The paper presents the flexible conjugate gradient algorithm in detail and explores strategies for preconditioning and sparsification. The algorithm is applied to a number of realistic power grid examples.
2015 IEEE International Conference on Smart Grid Communications (SmartGridComm)
Power grids reliability and security are influenced by transient behaviors of various power syste... more Power grids reliability and security are influenced by transient behaviors of various power system components. However, analyzing these transient behaviors needs to estimate millions of time-domain state variables with high computational efficiency. Most of the existing simulators are not based on parallel software platforms which have been proven to be powerful in many other applications. They are thus incapable of simulating transient behaviors of large-scale power systems efficiently. The lack of powerful dynamic simulation tool has become a major bottleneck towards the smarterization of power grids. Inventing a software based novel fully parallel topology of power systems, we propose a multi-threading based parallel simulator for transient behavior analysis in this paper. The accuracy and efficiency of the proposed simulator has been evaluated on IEEE and Polish standard bus systems, against the state-of-the-art open source software package (MatDyn). The results show that the runtime of the proposed simulator attains up to 80.49 ×speedup compared with MatDyn on 12-thread CPUs.
IEEE International Symposium on Circuits and Systems, 1996
Abstract-We describe the application of the PVL algorithm to the small-signal analysis of circuit... more Abstract-We describe the application of the PVL algorithm to the small-signal analysis of circuits, including sensitivity computa-tions. The PVL algorithm is based on the efficient computation of the Pad6 approximation of the network transfer function via the Lanczos process. The ...
2006 Ieee International Symposium on Circuits and Systems, 2006
Abstract The simulation of circuits containing silicon-on-insulator (SOI) transistors encounters ... more Abstract The simulation of circuits containing silicon-on-insulator (SOI) transistors encounters specific difficulties mainly due to the presence of the insulated body nodes, ie, connected by high impedance connections with the rest of the circuit. These high ...
2011 IEEE International Symposium of Circuits and Systems (ISCAS), 2011
ABSTRACT This paper described a model-order reduction (MOR) method based on a novel pure-nodal an... more ABSTRACT This paper described a model-order reduction (MOR) method based on a novel pure-nodal analysis formulation (PNA) which permits the use of symmetric, positive-definite Cholesky solvers for all circuit topologies. Moreover, frequently occurring special cases, e.g., inductor-resistor tree structures result in particular types of matrices that are solved by an even faster linear time algorithm. The model order reduction algorithms also uses symmetric-Lanczos iteration and non- standard inner-products for generating the Krylov subspace basis. Its efficiency is supported by a wide range of industrial examples.
2012 IEEE Power and Energy Society General Meeting, 2012
ABSTRACT This paper introduces a new paradigm for solving AC Power Flow (ACPF) and AC Optimal Pow... more ABSTRACT This paper introduces a new paradigm for solving AC Power Flow (ACPF) and AC Optimal Power Flow (ACOPF) with improved convergence robustness. This approach exploits the globally convergent properties of continuation methods. Continuation methods achieve robustness by generating a sequence of nonlinear problems and repeatedly and consistently providing good initial guesses for locally convergent nonlinear solvers such as Newton-Raphson. The Homotopy implemented in this paper, (referred to as Power Flow Homotopy, PFH), is formulated in a way that gradually transforms the “easy” DC into the “difficult” AC Power Flow. Successive changes of the homotopy parameter modify the system of equations from fully linear and convex DC into non-linear and non-convex AC (optimal) power flow. As a result, the AC solution is obtained with increased robustness and multiple AC power flow solutions can also be detected. Similarly, Optimal Power Flow Homotopy (OPFH) is defined for solving AC Optimal Power Flow, by gradually transforming the convex DC OPF problem. Simulation results provide a comparison between the simple Newton-Raphson method and PFH in terms of performance and quality of detected solution. Comparisons are also performed between the Interior-Point method and OPFH.
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Papers by Peter Feldmann