A new concept for a multilevel switched capacitor sinusoidal grid connected inverter

Abstract

A new topology for a dc to ac converter is presented here. The input stage of the new inverter is a current modulator which converts a dc voltage into a rectified sine-wave voltage at the required output frequency. The second stage is a single pulse 3-level inverter which reverses the even half-cycles to form the proper ac output. Inherently the losses of this configuration are low because the high switching frequency is performed by only two semiconductor switches in the first stage and the reversal is taking place at almost zero voltage and current in the second stage at the low switching frequency of 50Hz. The choice of the circuit parameters determines the frequency content of the output voltage which is generally lower than the other topologies. The promising features of low harmonic content, high efficiency and voltage step up characteristic makes it a good candidate for grid connected-renewable energy sources. The work is carried out by extensive simulations on PSIM.