摘要： In this paper, a step-up transformerless inverter topology is investigated for the grid-connected solar PV system. This proposed topology combines the features of the DC-DC step-up converter and two-level inverter. The important features of this topology are: First, the proposed topology keeps the negative terminal of the PV source directly connected with the neutral of the grid. Therefore, there is no variation in the CMV, which appears across the PV parasitic capacitance, resulting in negligible leakage current and higher efficiency. Negligible leakage current makes this topology highly suitable for transformerless grid-connected solar PV application; second, due to the step-up feature of the proposed topology, the inverter output voltage can be greater than the input DC voltage of solar PV which makes the proposed topology suitable for connecting lower voltage solar PV modules. The topology works with a simple and dedicated PWM scheme, which consists of certain logic operations as explained in the text. The modes of operation, design of the converter, PWM strategy, and analysis are presented in detail. The MATLAB/Simulink environment is used to simulate the proposed grid-connected system for 300W power rating and all the results are included in the paper, which shows that the proposed system gives higher efficiency with lower THD in grid-current.