H. Ghoudjehbaklou and A. Kargar
Three different active power filter (APF) configurations are developed for harmonic elimination of a three‐phase electric arc furnace (EAF). Three single‐phase APF, a three‐wire…
Abstract
Three different active power filter (APF) configurations are developed for harmonic elimination of a three‐phase electric arc furnace (EAF). Three single‐phase APF, a three‐wire APF and a four‐wire APF are developed for this purpose. A predictive control method of the APFs based on dynamic programming method is applied and the results of the simulation studies are compared. Finally the stability of the system is analyzed and its global asymptotic stability is shown.
Details
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Dariusz Grabowski and Janusz Walczak
Electric arc furnaces are usually modelled using combined models which divide the phenomenon taking place in real objects into a deterministic and a stochastic or chaotic parts…
Abstract
Purpose
Electric arc furnaces are usually modelled using combined models which divide the phenomenon taking place in real objects into a deterministic and a stochastic or chaotic parts. The former is expressed by a nonlinear differential equation. The goal of this paper was to obtain a closed form of the solution to one of the most popular nonlinear differential equations used for the AC electric arc modelling.
Design/methodology/approach
The solution has been obtained in the time domain by a sequence of transformations of the original nonlinear equation which lead to a linear equation, for which a closed form solution is known.
Findings
The paper provides a set of parameters for which the solution to the nonlinear differential equation describing electric arc can be obtained in a closed form.
Research limitations/implications
There are still some parameter values for which the solution can be found only numerically. Moreover, due to the nature of the phenomena occurring in electric arc furnaces, in order to build a complete model of the arc the deterministic model must be extended using for example stochastic approach.
Practical implications
The obtained results enable determination of exact waveforms of the arc voltage or radius without application of numerical algorithms for ODE solving. The arc model can be used to evaluate the impact of arc furnaces on power quality during the planning stage of new plants. The proposed approach facilitates calculation of the arc characteristic.
Originality/value
The importance of having a closed form of the solution instead of the numerical ones comes from new possible ways of extension of the arc model in order to cover the time‐varying nature of the arc waveforms. So far the equation has been solved only using numerical algorithms.