Realization of an asymmetric Switched-Capacitor Multilevel Inverter using Nearest Level Control

In this paper, a thirty-one-level multilevel inverter (MLI) with switched-capacitor (SC) is proposed. This topology consists of two asymmetric DC voltage sources as input, four capacitors, sixteen semiconductor switches and two diodes. Each of these units acts as DC-DC converter. Modified H Bridge which acts as a polarity generator is sandwiched between two basic units. The left side of the circuit feeds three (V, 2Vand 3V) DC voltage levels while right side unit produces (4,8V and 12V) voltage levels. The proposed inverter naturally solves the problem of capacitor voltage balancing by selecting proper values of capacitance. Nearest- level control (NLC) technique is used to reduce the distortion in output voltage. This topology also eliminates the problem the having multiple DC sources and can also be connected to the grid. The proposed inverter is simulated in MATLAB®/Simulink 2016a. Significant reduction in total harmonic distortion (THD) is observed in output voltage and current of the inverter which is according to IEEE-519 standards for harmonics.