SIMULATION OF FUZZY BASED MODULAR MULTILEVEL DC /DC CONVERTER WITH FAULT BLOCKING CAPABILITY FOR HVDC INTERCONNECTS

Abstract

This paper presents the first dynamic
model of the DC-MMC, a new class of modular
multilevel single-stage dc/dc converters aptly
suited for HVDC systems. DC-MMC, that can be
deployed to interconnectHVDC networks of
different or similar voltage levels. Its key features
include bidirectional power flow, step-up and
step-downoperation, and bidirectional fault
blocking similar to a dc circuitbreaker. The
kernel of the DC-MMC is a new class of
bidirectionalsingle-stage dc/dc converters utilizing
interleaved strings of cascaded submodules. A
Fuzzy logic Controller is implemented for DCMMC
operation is analyzed and anopen loop
voltage control strategy that ensures power
balance ofeach sub module capacitor via
circulating ac currents is proposed.
MATLAB/Simulink software is used for to
simulate the DC-MMC with the proposed control
strategy.