Caracterização de fenômenos de alta frequência em sistemas de acionamento de processos de tratamento de minério

Abstract

This work has as its object of study the various phenomena of high-frequency which are present in PWM motor drives, such as (i) transient overvoltages in the terminals of the machine, (ii) differential mode currents circulating by the cables and (iii) common mode currents that flow through the grounding system. In this context, the objective of this work is to characterize these systems drive problems present in the activities of mining and pelletizing, indicating, among other things, their gravity. To achieve this goal, was selected and subsequently simulated, a real drive system present in mining processes, whose features presents potentially higher severity problems as mentioned above, such as those that uses larger extension cables. Also have been reported processes in what these motors operate, describing the equipment powered by them and the functions they perform within the process. For carry out the simulations, a complete modeling of the selected electrical systems was made, in which all characteristics were detailed and reproduced, as (i) grounding (or not) of transformer, (ii) the characteristics of frequency converter and the filters used, (iii) the type, the geometric arrangement and form of installation of power cables and, finally, (iv) the characteristics of the motor and grounding system. With the implementation of computational platform, the system was simulated and the presence and severity of high-frequency phenomena in focus was evaluated.