Alternate arm converter operation of the modular multilevel converter

A new operating mode of the Modular Multilevel Converter (MMC) using modified arm current waveforms inspired from the working principle of the Alternate Arm Converter (AAC) is presented in this paper. A reduction in the cell voltage deviation is observed at power factors close to unity at the cost of an increase in power losses, especially when reactive power is required. This gain in voltage margin is then used in further optimizations of the MMC performance, mainly focusing on either increasing the number of redundant cells or improving the overall power efficiency of the converter.