Performance Analysis of Neutral Point Clamped and Cascade H-Bridge Multilevel Converter Interfaced With Solar Photovoltaic System to Reduce Total Harmonic Distortion

Abstract

Present day industrial applications require higher power apparatus for power conversion. At medium voltage grid, to connect only one power semiconductor switch directly is a not practically successful concept to overcome this multilevel power converter has been studied as an alternative in high power and medium voltage applications. Renewable energy sources like photovoltaic, wind, fuel cells can be conveniently interfaced to a multilevel converter system. Solar photovoltaic system becomes more popular among other renewable energy system, therefore Power electronics devices have been become an indispensable part for renewable energy system. This paper demonstrates comprehensive analysis and comparison of the Total harmonics distortion (THD) in detail of multilevel converter for different levels by modelling and simulation when interfaced with Solar Photovoltaic (PV) system. The results presented give an understanding for the implementation of the multilevel converter in the solar PV system. The modular structure for the multi level inverters allows extending higher number of levels easily for future studies with less complexity comparably. The simulation results are carried out using two different topologies for multilevel converter, neutral point clamped (NPC) and cascade H-bridge (CHB). The main focus of this paper is to present physical modelling and simulation of solar PV system and multilevel converter for different levels. The results displayed are such that the output gets smoother as the levels increases and the total harmonics distortion decreases. The solar PV system used is modelled in SIMCAPE library. All the simulation studies are carried out under MATLAB/Simulation environment.