This book reports on a comprehensive study on a novel high-power converter, i.e. a Modular Multilevel Converter with Interleaved Half-bridge Submodules (ISM-MMC). It describes in depth its average model, the operating principles, as well as a new control method and a hybrid modulation strategy that help to exploit the benefits of the interleaving scheme. The new power converter is particularly advantageous for high-current applications that require superb quality of input/output waveforms. Moreover, this book reports on a systematic study of the current balancing problem between parallel-connected units that commutate in non-simultaneous fashion. This is a typical issue in interleaved converters, however here it is analyzed for the first time in relation to MMC-based structures. Two control strategies are proposed to cope with this matter. By using a sensorless regulation scheme, the number of required current transducers has been minimized, reducing complexity, cost, and footprintof the hardware, while providing converter with a fast and accurate current balancing. This book also offers a comprehensive comparison between several practical designs of ISM-MMC and classical MMC for an ultra-fast electrical vehicle charger. All in all, it provides graduate students and researchers, as well as field engineers and professionals with extensive information and essential practical details on the state-of-the-art MMC and ISM-MMC design.