The article discusses an improved automatic electrodes movement control system for electric arc furnaces (arc steel-making furnaces and ladle-furnace installations), which improves the dynamic parameters of the quality of secondary electrical circuit impedance (s) control due to the use of a new structure of a nonlinear adaptive impedance controller. The use of an improved control system stabilizes the metal charge melting process in arc steel-making furnaces as well as the liquid steel heating process in ladle-furnace installations with intensive bottom blowing. This allows for the technical effect of reduced operating time under current and reduced specific power consumption in electric arc furnaces. The non-linear adaptive impedance controller provides full linearization of control loops, including a proportional directional control valve (servo valve) with a non-linear control characteristic and a secondary electrical circuit with a non-linear dependence of impedance on the arc length. The research used a complex mathematical model of the electric circuit of an electric arc furnace, hydraulic drives for moving electrodes and an automatic control system for moving electrodes, implemented in the MATLAB Simulink mathematical package. The effectiveness of the improved control system in the conditions of the existing metallurgical production was evaluated against the example of the “RADUGA NPA PK” control system, developed at the Federal State Budgetary Educational Institution of Higher Education “MSTU im. Nosov” and a ladle-furnace operating at the installation in the electric steel-smelting shop of PJSC “Magnitogorsk Metallurgical Plant”. The developed improved control system can be used in other modern electric arc furnaces of various capacities operating at metallurgical enterprises in Russia and abroad.

This paper deals with design features of the converters for synchronous motors vector-pulsed launch control.

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