Re-generative asymmetrical multi-level converter for multi-megawatt variable speed drives

This paper is focused on the design, modulation and control of a re-generative non-symmetrical multi-level converter for high-power applications such as oil and gas or mining. The converter is based on standard IGBT modules and the DC-link voltages are chosen in order to be easily implemented for real industrial motor drives. The modularity of the suggested topology can help to drive up to 60 MW using PWM strategies in normal mode of operation. The output voltage has 23 levels, enabling nearly no torque ripple and avoiding to use an output sine filter. A new control strategy is suggested to reduce power-switch losses and to increase the availability of the proposed converter.