Omid Fatemi - Department of Electrical Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Nader Sargolzaei - Department of Electrical Engineering, Mashhad Branch, Islamic Azad University, Mashhad, Iran

In electric arc furnace, molten steel is produced by electrical energy conversion to heat. High current arcs cuased by applying electrical energy source to electrode graphits melt the raw materials. Electrode control plays an important role in improving efficiency for electric arc furnaces. However, nonlinear nature of arc column limits control performance. The main purpose of electrode control in arc furnace is to track current or resistance set-points by adjusting arc length. In this paper, nonlinear chaotic modeling of electric arc furnace system is presented. In order to design sliding mode control, uncertain affine model is assumed for arc resistance dynamics. Then, adaptive-fuzzy system is designed to estimate uncertain parameter and switching control law. Adaptation law is derived by Lyapunov synthesis method. Finally, a secondary sliding mode controller was designed for hydraulic actuator closed-loop system. Simulation results and performance criteria indicate satisfactory tracking performance for arc resistance in presence of parametric uncertainty and external disturbances.

Electric arc furnace, Sliding mode control, Adaptive-fuzzy approximation, fuzzy switching, electrode control