This paper presents a new control strategy using model-based predictive current control (MB-PCC) for a doubly fed induction machine (DFIM) driven by an indirect matrix converter (IMC). This strategy proposes the control of rotor currents, whose references are calculated from active and reactive stator power set points and the dynamic model of the DFIM. The control strategy works well in the four P-Q operating regions of the DFIM. The grid synchronization process is carried out by setting the P-Q power set points to zero. The results presented include the DFIM synchronization procedure as well as the active and reactive power control at variable shaft speed to validate the feasibility of the proposed strategy.

Electric Arc Furnaces (EAFs) are processes with an intensive consumption of energy, in modern arc furnaces the specific energy conception ranges is around 0.5 MWh per ton of produced liquid steel. In such furnaces small improvements in efficiency represents significant savings. Electric arcs are highly nonlinear and chaotic, and their use in the arc furnaces for scrap melting introduces a very high harmonic distortion in the power systems. To improve the understanding of power phenomena at the arc furnaces, this paper proposes the application of the Current's Physical Components (CPC) power theory, and based on this analysis an interpretation of each the current components is provided. Real EAF voltage and current measurements are computed for a complete melting and heating process. This study proposes the use of the current components as performance indicators and gives some ideas about how to improve the operation and control to optimize the electrical energy used at the arc furnaces.