True unit power factor active front end for high capacity belt conveyor systems

Belt conveyors in mining industry constitute an efficient and economical way for minerals and heavy load transportation from mines to their destination. The ongoing desire to further extend the length, speed and capacity of the conveyors, has led to the increasing size of the conveyor drive systems. More and more frequently, high-capacity belt conveyors are efficiently driven employing medium-voltage power converters connected with large induction motors. Power converters in the MW range are often used, increasing the power quality issues in the grid system. This work proposes a new True Unit Power Factor Active Front End for regenerative multi-motor conveyor drive systems. The proposed solution eliminates all the current harmonics in the range considered by the international standards without using sinusoidal filters. Three-winding conventional transformer and well established medium-voltage power converters are considered to ensure the robustness and simplicity requirements.