Three Phase Eleven Level Modular Multilevel Inverter with PD-PWM for Grid Connected System

The prominence of Modular Multilevel Inverters (MMI) is rising owing their merits of simple mechanical construction and good voltage sharing for semiconductor devices. Mostly Multilevel Inverters use more than one source; however, the effective use of all the sources at all levels is rare. Conventional Multilevel Inverters will diminish the energy efficiency of the conversion system. When compared to conventional multilevel inverter, Modular Multilevel Inverter with a high numbers of voltage levels seem to be the most suitable because of the use of an isolated dc source. This paper explores a three-phase eleven level modular multilevel inverter with phase disposition pulse width modulation technique (PD-PWM) that can extract power from all the sources at all the levels. Besides, this paper develops a synchronous d-q reference frame controller to control the current of 11kV. When compared with Reduced Switch Count based Multilevel Inverter Series/Parallel switching topologies, the Modular Multilevel Inverter provides better Total Harmonic Distortion (THD) of output voltage and utilization factor.