Modular multilevel converter for medium-voltage applications

This paper investigates the suitability of the modular multilevel converter (M2C) for medium-voltage multi-megawatt machine drives and as an interface for the integration of renewable power to the grid. Therefore, emphasis is given to issues that may affect the performance in these applications such as ac and dc side harmonics, dv/dt the interfacing transformer or machine windings may experience, suppression of common mode voltage, and switching strategy that may minimize the overall number transitions per fundamental period in order to suppress switching losses without significantly compromising output voltage waveform quality. The modular multilevel converter with 16 cells per arm operated in inversion and rectification modes is used to demonstrate the viability of the M2C in medium-voltage high-power applications.