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Stability of ideal thyristor and diode switching circuits
 IEEE Trans. Circuits and Systems, Part
, 1995
"... AbstrQctThis paper analyzes the stability of a general RLC circuit with ideal thyristors or diodes and periodic sources. Applications include high power thyristor controlled reactor and bridge rectifier circuits. The periodic steady states of the circuit are analyzed using a Poincar6 map and transv ..."
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Cited by 7 (2 self)
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AbstrQctThis paper analyzes the stability of a general RLC circuit with ideal thyristors or diodes and periodic sources. Applications include high power thyristor controlled reactor and bridge rectifier circuits. The periodic steady states of the circuit are analyzed using a Poincar6 map and transversal&y conditions are given to guarantee the smoothness of the Pgincar6 map. A simple and exact formula for the Jacobian of the Poincar6 map is proved. Account is taken of the varying state space dimension as diodes switch on and off. When the transversality conditions fail, switching times can jump or bifurcate. Examples show that these switching time bifurcations can cause instability of thy&or circuits and mode changes of diode circuits. The simplification of the Jacobian formula is used to explain why the switching time bifurcations occur and are not predicted by the eigenvalues of the Jacobian. Periodic orbits of ideal diode circuits are proved to be stable using Jacobian and incremental energy methods. A source of damping in switching circuits is identified. A I.
PETS—A Simulation Tool for Power Electronics
 IEEE Workshop on Computers in Power Electronics
, 1996
"... Transient Simulator), a program for timedomain analysis of power electronic circuits. Methods implemented in PETS include standard techniques such as the modi ed nodal approach to forming system equations, and numerical integration with automatic timestep control, together with new techniques inclu ..."
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Cited by 6 (3 self)
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Transient Simulator), a program for timedomain analysis of power electronic circuits. Methods implemented in PETS include standard techniques such as the modi ed nodal approach to forming system equations, and numerical integration with automatic timestep control, together with new techniques including a state determination algorithm, and representation of elements to maintain a constant system matrix. The simulator supports arbitrarily complex piecewiselinear models and smooth nonlinear models using a delay approximation. The methods implemented in PETS are illustrated using two examples: a quadratic buck converter, and a closedloop powerfactor corrector. 1
Switched networks and complementarity
 IEEE Transactions on Circuits and Systems I: Fundamental Theory and Applications
"... Abstract—A modeling framework is proposed for circuits that are subject both to externally induced switches (time events) and to state events. The framework applies to switched networks with linear and piecewiselinear elements, including diodes. We show that the linear complementarity formulation, ..."
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Cited by 4 (3 self)
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Abstract—A modeling framework is proposed for circuits that are subject both to externally induced switches (time events) and to state events. The framework applies to switched networks with linear and piecewiselinear elements, including diodes. We show that the linear complementarity formulation, which already has proved effective for piecewiselinear networks, can be extended in a natural way to also cover switching circuits. To achieve this, we use a generalization of the linear complementarity problem known as the conecomplementarity problem. We show that the proposed framework is sound in the sense that existence and uniqueness of solutions is guaranteed under a passivity assumption. We prove that only firstorder impulses occur and characterize all situations that give rise to a state jump; moreover, we provide rules that determine the jump. Finally, we show that within our framework, energy cannot increase as a result of a jump, and we derive a stability result from this. Index Terms—Complementarity systems, hybrid systems, ideal diodes, ideal switches, piecewiselinear systems. I.
Implementation of a Decoupled Optimization Technique for Design of Switching Regulators Using Genetic Algorithms
"... Abstract—This paper presents an implementation of a decoupled optimization technique for design of switching regulators using genetic algorithms (GAs). The optimization process entails the selection of component values in a switching regulator, in order to meet the static and dynamic requirements. A ..."
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Abstract—This paper presents an implementation of a decoupled optimization technique for design of switching regulators using genetic algorithms (GAs). The optimization process entails the selection of component values in a switching regulator, in order to meet the static and dynamic requirements. Although the proposed method inherits characteristics of evolutionary computations that involve randomness, recombination, and survival of the fittest, it does not perform a wholecircuit optimization. Thus, intensive computations that are usually found in stochastic optimization techniques can be avoided. Similar to many design approaches for power electronics circuits, a regulator is decoupled into two components, namely the power conversion stage (PCS) and the feedback network (FN). The PCS is optimized with the required static characteristics, whilst the FN is optimized with the required static and dynamic behaviors of the whole system. Systematic optimization procedures will be described and the technique is illustrated with the design of a buck regulator with overcurrent protection. The predicted results are compared with the published results available in the literature and are verified with experimental measurements. Index Terms—Circuit optimization, circuit simulation, computeraided design, genetic algorithms, power electronics. I.
Interval Algorithms For Finding The Minimal Root In A Set Of Multiextremal OneDimensional Functions
, 1999
"... . Two problems very often arising in applications are considered. The rst problem consists of nding the minimal root of an analytic onedimensional function over a given interval. It is supposed that the objective function can be multiextremal and nondierentiable. The second problem is a generaliza ..."
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. Two problems very often arising in applications are considered. The rst problem consists of nding the minimal root of an analytic onedimensional function over a given interval. It is supposed that the objective function can be multiextremal and nondierentiable. The second problem is a generalization of the rst one and deals with the search of the minimal root in a set of the functions. New algorithms based on Interval Analysis and BranchandBound Global Optimization approaches are proposed for solving both problems. Numerical experiments carried out on a wide set of test functions demonstrate a quite satisfactory performance of the new algorithms in comparison with interval analysis techniques traditionally used for nding roots of equations. Key words. Minimal Root, Interval Analysis, BranchandBound. AMS subject classications. 6504,6505,65G10,65H20,65K05,90C30 1. Introduction. There exist many applications where the problem of nding the roots of onedimensional funct...
The OSMOS Consortium (2001b). Proposed intercompany interaction process model
 OSMOS Project Deliverable (D1.2 Iteration 2
, 1994
"... Abstract A method for fast timedomain simulation of piecewiselinear networks with switches is described in this paper. The method is based on a discretetime switch model that consists of a constant conductance in parallel with a current source. In each simulation step, value of the current sourc ..."
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Abstract A method for fast timedomain simulation of piecewiselinear networks with switches is described in this paper. The method is based on a discretetime switch model that consists of a constant conductance in parallel with a current source. In each simulation step, value of the current source is updated as a function of known network signals. The function [4], [5], [6], ideal switch model is assumed, while references [7], [8], [lo] propose various simple approximations to the ideal switch model. An ideal switch has zero impedance when on, zero admittance when off, and switches between the two states in takes one of two forms, depending on the state (on or off) of the switch. Since system matrix is constant, regardless of the states of the switches, simulation time is essentially the same as for linear, timeinvariant network of the same complexity. The paper discusses selection of model and simulation parameters. zero time. With n ideal, singlepole, singlethrow switches, the switching converter network reduces to one of 2 " possible switched networks (without switches). Then, one approach is to write and solve statespace equations for each of the Simulation algorithm is described and an example is included. It is shown that the method is not only efficient but also quite general and void of convergence problems. Its primary application is for longterm transient simulation of power electronic systems. switched networks, and to establish conditions for transitions of switched networks. Explicit solution to state equations requires the state transition matrix for each of the switched networks. The matrices can be approximated with truncated Taylor [l], [2], [3] or Chebyshev [4] series. In the statespace I.
Modelling, Wellposedness and Stability of Switched Electrical Networks ⋆
"... Abstract. A modeling framework is proposed for circuits that are subject to both time and state events. The framework applies to switched networks with linear and piecewise linear elements including diodes and switches. We show that the linear complementarity formulation, which already has proved ef ..."
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Cited by 2 (2 self)
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Abstract. A modeling framework is proposed for circuits that are subject to both time and state events. The framework applies to switched networks with linear and piecewise linear elements including diodes and switches. We show that the linear complementarity formulation, which already has proved effective for piecewise linear networks, can be extended in a natural way to cover also switching circuits. We show that the proposed framework is sound in the sense that existence and uniqueness of solutions is guaranteed under a passivity assumption. We prove that only firstorder impulses occur and characterize all situations that give rise to a state jump; moreover, we provide rules that determine the jump. Finally, we derive a stability result. Hence, for a subclass of hybrid dynamical systems, the issues of wellposedness, regularity of trajectories, jump rules, consistent states and stability are resolved. 1
An Algorithm for Solving PiecewiseLinear Networks that Include Elements with.Discontinuous Characteristics
"... Abstract In this paper, am algorithm for solving piecewiselinear networks that include elements with discontinuous characteristics is presented. The algorithm is based on modifications of the Katzenelson algorithm that traces the solution curve through regions where boundary conditions are satisf ..."
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Abstract In this paper, am algorithm for solving piecewiselinear networks that include elements with discontinuous characteristics is presented. The algorithm is based on modifications of the Katzenelson algorithm that traces the solution curve through regions where boundary conditions are satisfied. Jumps in the network output variables, caused by state changes of elements with discontinuous characteristics, may in turn result in additional state changes of piecewiselinear elements. To resolve these state changes, the network solution point is dragged over the line segment that connects the solution points at the discontinuity, and the network state is changed whenever boundary conditions are violated. Since the algorithm traces cause and effect sequence of state changes, it is well suited for application in timedomain simulations. The algorithm has been implemented in a simulator for piecewise linear networks, and extensively tested on networks encountered in power eiectroinics. An example of such application is presented. I.
Computer Simulation of ContinuousTime and Switched Circuits: Limitations of SPICEFamily Programs and Pending Issues
"... Abstract. The contribution deals with some open problems from the area of Transient and AC analyses of large continuoustime and switched circuits with the focus on switched capacitor circuits and switched DCDC converters. The discussed weak points of SPICElike and SPICEcompatible simulation prog ..."
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Abstract. The contribution deals with some open problems from the area of Transient and AC analyses of large continuoustime and switched circuits with the focus on switched capacitor circuits and switched DCDC converters. The discussed weak points of SPICElike and SPICEcompatible simulation programs consist in the absence of finding effectively the steadystate, in an inefficient integration algorithm for the transient analysis of switching phenomena, and in the absence of a direct AC analysis of switched circuits. The paper also describes some new approaches, which could be helpful in overcoming the above limitations.
A Fast algorithm for Finding the First ZeroCrossing in a set of Signals based on Interval Arithmetic
"... i = 1; : : : ; Ng (1) Even for N = 1 it is usually difficult to solve (1) in an analytical way and numerical methods must be used to find an fflapproximation x ffl of the point x* such that f k (x ffl ) 0; jx ffl \Gamma x j ! ffl; k = 1; : : : ; N (2) In addition, functions may be (and usually a ..."
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i = 1; : : : ; Ng (1) Even for N = 1 it is usually difficult to solve (1) in an analytical way and numerical methods must be used to find an fflapproximation x ffl of the point x* such that f k (x ffl ) 0; jx ffl \Gamma x j ! ffl; k = 1; : : : ; N (2) In addition, functions may be (and usually are) multiextremal, that is why local techniques can not be applied in this case and grid techniques are used by engineers to solve the problem. Grid techniques are based on sampling the set of signals from the left margin of the interval in step of size ffl until a signal f i ! 0. This method is very reliable but the number of evaluations for each f i is too high. In [1] two new m