Improvement in Performance of Asymmetric Multilevel Inverter Used for Grid Integrated Solar Photovoltaic Systems

Abstract

The multilevel inverter has gained significant attention for medium and high voltage applications. The neutral point-clamped, flying capacitor, and cascaded H-bridge (CHB) inverters are the bais topologies. It tends to be more gorgeous by increasing the number of levels in output waveform with lower rated voltage sources and power semiconductor devices. This significantly improves output power quality, e.g. lower total harmonic distortions (THDs). However, switching loss of the inverter is the critical issue as the inverter uses a large number of switches. This paper proposes different multicarrier switching techniques which are applied to a CHB inverter having two unequal dc supplies to generate seven level output voltage. These proposed topologies generate more output level than conventional topology which results in reduced total harmonic distortion. Additional vital feature of this proposed multicarrier switching topology is that fundamental rms output voltage increases which increases the output power level. These new proposed multicarrier switching topologies are compared with conventional techniques. This comparison is made in terms of THDs, fundamental output voltage and inverter loss. Finally, the efficacy of the proposed system has been validated through simulation analysis in the MATLAB/Simulink software environment.