ASYMMETRICAL MULTILEVEL INVERTER-BASED PV SYSTEM WITH VOLTAGE FEEDBACK CONTROL: AN EXPERIMENTAL VALIDATION

Abstract

This paper presents an experimental evaluation and validation of a standalone photovoltaic (PV) renewable energy system using a perturb and observe MPPT-based voltage controller (POVC) for application on the reduced component multilevel inverter (MLI). The objective is to verify the effectiveness of POVC and asymmetrical MLI for real PV interconnection applications, which has never been reported before. An asymmetrical 17-level MLI topology is selected in this research. It requires four isolated DC sources to operate. A boost converter is deployed as one of the inputs while isolated DC power supplies power to the others. POVC is implemented at the boost converter to control the DC voltage from the PV panel. From the experimental results, the capability of the POVC to produce constant voltage levels under varying conditions is proven. It is also capable of delivering maximum power under maximum load. The full system is tested using different load types, including nonlinear loads. The MLI produces expected outputs under all operating conditions with efficiencies above 97%. The viability of the proposed PV system is firstly analysed through MATLAB/Simulink simulations. The results are then evaluated experimentally.