Abstract

Abstract :
Ripple in the module voltage is the common issue in the modular multilevel converter (MMC). To rectify this issue, an enhanced MMC has been implemented in this paper. The proposed converter contains the enhanced the auxiliary circuit which is placed in between the arms of the converter and this converter operated at fundamental and below the fundamental frequencies operations of the load. The proposed auxiliary circuit has been designed with reduced number of components with the existing auxiliary circuits. The enhanced converter has been operated at 50 Hz and 10 Hz frequencies under steady state load condition. With these conditions also the proposed enhanced converter have been improved the performance in terms of voltage ripple reduction in module capacitor voltage, circulating current and arm voltage balancing because of the enhanced circuit is generating additional power which may redistribute from the top arms to lower arms of the converter which may compensate the ripple components in the capacitor voltage. Further the working operation of the proposed converter under steady state condition, mathematical approach, and proposed control strategy have to be explained in detail. The enhanced converter performance has been tested and verified with the MATLAB/SIMULINK and HIL test.

Key words: Enhanced MMC, module capacitor voltage ripple reduction, circulating current, Modified Proportional integral (PI) controller.