Utilization of Supplementary Energy Storage Systems in High Power Mining Converters

This paper proposes the utilization of ultracapacitor as additional energy storage device in high power AC mining converters. A critical requirement for these converters is to be able to maintain a robust DC link under all operating conditions. However, due to lower switching frequencies of the IGBT devices, the bandwidth of the controllers is limited. As a result, during regenerative periods, the DC link voltage may have a tendency to increase. Protective devices like choppers and crowbars are added to the system. Integration of the ultracapacitor system to the converter can aid the recovery and storage of the regenerative energy and reutilize that energy for meeting the systems power demand. This will improve the overall performance of the system and reduce the dependence on the chopper and crowbar circuits. Implementation of this system translates to power quality improvement of the main grid.