I. Introduction
Centralized high-power ac-dc voltage source converters (VSC) are in high demand in today's industries. Application examples include: electric traction drives, uninterruptible power supplies (UPS), commercial-scale microgrids [1], motor drive active front ends (AFE), high voltage dc transmission [2], etc. Low-pass filters are usually placed between the semiconductor switches and the power grid for attenuating high-frequency harmonics [3]. The power rating of the converter in this paper's application is 1 MVA. Most modern power semiconductor devices for these power levels operate at frequencies below 10 kHz due to switching loss constraints. The volume of the filter inductor is inversely proportional to the switching frequency; therefore, the inductor represents considerable weight, volume and cost of the converter system.