Modular Multilevel Serial-Parallel Converter (MMSPC) for the Tokamak SMART

This paper presents a novel architecture for mod-ular power converters designed for pulsed power applications, based on a Modular Multi-Cell Series-Parallel Power Converter (MMSPC) topology integrated with supercapacitor (SC) energy storage for implementation in the SMall Aspect Ratio Tokamak (SMART). The proposed topology ensures continuous series-parallel reconnection of each cell, allowing operation in either voltage or current mode, depending on the profiles established by the experiment. In this case, the parallel configuration provides natural cell balancing, eliminating the need for additional voltage sensors or control mechanisms. In addition, all cells are equal, and the modular architecture of the system facilitates cell maintenance and replacement. The results obtained show the operating points of the converter according to the current requirements imposed (70 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$kA$</tex>) with the dynamics defined by the experiment (350 kA/s). During the active period, the energy is continuously distributed and balanced between the SC. This validates the effectiveness of the reconfiguration and control scheme in maintaining uniform cell utilization and thermal balance across the converter.