Due to some excellent features, such as higher voltage handling capability and the ability to produce high quality output power, the modular multilevel cascaded (MMC) converter is considered as one of the most promising converter topologies. Power quality is an important issue for MMC inverter and total harmonic distortion (THD) is considered as the major power quality indices. Modulation technique plays a vital role for determining the power quality of MMC inverter. In this paper an advanced modulation technique is proposed for a 3-phase 15 level MMC inverter system. The proposed switching technique offers lowest THD (4.89%) and reduced inverter loss compared to existing modulation techniques. The proposed modulation technique is verified in MATLAB/Simulink environment.