Intelligent control of a novel transformerless inverter topology for photovoltaic applications

Abstract

Transformerless inverters are prone to irregular voltage profiles, high harmonics and isolation problems while operating with photovoltaic systems and varying load conditions under stand-alone mode. The aim of the paper is to identify the drawbacks of transformerless inverters operating in stand-alone mode and to propose a new topology with improved performance and control. Further, an intelligent controller is designed to operate the proposed topology with various loads and varying load conditions. The developed controller achieves voltage regulation and low total harmonic distortion for the proposed topology when simulated under MATLAB/Simulink environment. Further, a laboratory prototype of the proposed inverter operating under stand-alone photovoltaic application is developed and operated with the developed control method. The proposed topology along with the developed controller achieves output voltage regulation and reduced THD under varying load conditions. The THD of the proposed system while operating with constant load is observed to be 1.8%, and for varying load condition, it is around 2.12%. Further, the efficiency and power loss of the system are calculated, and it is observed the system exhibits 98.5% efficiency. The achieved results are better when compared with existing work.