A New H7 Transformer-less Single-Phase Inverter to Improve the Performance of Grid-Connected Solar Photovoltaic Systems

Abstract

Solar energy has a substantial role to play for meeting the ever-increasing energy demand. Due to some appealing features, such as higher performance, reasonable cost, and suitable power density, grid-connected transformer-less photovoltaic (TLPV) inverters have become prevalent in solar energy-based applications. This paper lays the groundwork for a new grid-connected TLPV inverter topology with reduced common mode current and improved performance. This novel inverter topology contains reduced common mode current and less total harmonic distortion (THD) with improved power quality. Midpoint clamping method is applied to eliminate extra leakage current. Unipolar sinusoidal pulse-width modulation method is used to control the power switches. The common mode voltage is held constant to reduce the common mode current to 8.03 mA. The leakage current suppression is analyzed in detail with simulation results. The switching technique does not affect the efficiency, however, reduces the leakage current. Output current and voltage THDs are found to be 0.54% and 0.95%, respectively, using an LCL filter, which is better than those of the other existing topologies. The proposed topology can provide efficiency of 98.23%. The inverter topology is tested and its performance is analyzed on MATLAB/Simulink platform.