Abstract
A new Modular Multilevel Converter with Interleaved half-bridge
Sub-Modules (ISM-MMC) is proposed in this paper. The ISM-MMC exhibits a
higher modularity and scalability in terms of current ratings with
respect to a conventional MMC, while preserves the typical voltage level
adaptiveness. The ISM-MMC brings the known advantages of classical MMC
to low-voltage, high-current applications making it a novel candidate
for the sector of ultra-fast chargers for all types of electrical
vehicles (EV). This advanced topology makes it possible to easily reach
charging power of the EV charging system up to 4.5 MW and beyond with
low-voltage supply. To operate the new converter, a hybrid modulation
scheme that helps to exploit advantages of the interleaving scheme, is
implemented, and explained in this paper. It has been verified that the
typical MMC control methods are still applicable for ISM-MMC. A
comparative study between classical MMC and ISM-MMC configurations in
terms of output characteristics and efficiency is also given.
Furthermore, it has been demonstrated that the number of ac voltage
levels is synthetically multiplied by the number of interleaved
half-bridge legs in submodules. Numerical simulations and
Hardware-in-the-Loop tests are carried out to demonstrate the
feasibility of the proposed topology and implemented modulation scheme.