A modified cascaded H-bridge multilevel inverter for solar applications

In this paper, a modified cascaded H-bridge multilevel inverter (MLI) is proposed and designed for solar applications. Generally, as the level of conventional multilevel inverter increases, the required number of switches and size increases. The proposed topology is cascade of unit stages which involves 5 switches and two voltage source; moreover a unit stage is capable of generating 5 levels. Also, the detailed analysis of cascaded multilevel inverter is discussed which incorporates three different methodologies involving less number of power devices in order to generate maximum number of levels. This results into reduction in gate drive circuitry and less switching losses. The proposed MLI is designed for power 1.5kW and Inphase level shifting SPWM technique has been incorporated in which 5kHz carrier wave is compared with 50Hz of sinusoidal wave with a modulation index of 0.8. As a result, total harmonic distortion (THD) is achieved as 4.71% with LC-filter for above mentioned multilevel inverter. The circuits are modeled and simulated with the help of MATLAB/SIMULINK.