Fault-tolerant medium-voltage power converters for high-capacity belt conveyor systems

The bulk materials transportation from the mines to their destination is an important activity that often represents the major part of the total mining costs. More and more frequently, high-capacity belt conveyors in mining are efficiently driven employing medium-voltage power converters connected with large induction motors. Unfortunately, medium-voltage power converters use a high number of power semiconductors which are ranked as the most fragile components of a drive system and the failure of any of these devices often causes a total collapse of the converter, resulting in the conveyor system downtime with large financial losses for companies. In this work the authors will present new design alternatives for the most used power converter technologies aiming its fault-tolerant and fault-resilient operation. As the total tolerance to any kind of failure is still a practical impossibility, in the cases where catastrophic failures cause the converter breakdown and the conveyor downtime, it will be shown how to limit the damage pattern in the equipment, minimizing the maintenance costs and time-to-repair.