A Novel Single-Phase Voltage Boosting Transformerless Inverter Topology for Grid-connected Solar PV Application

This paper proposes a new voltage boosting transformerless inverter (VBTI) topology for photovoltaic (PV) applications. The proposed VBTI topology is developed by integrating the coupled inductor based high voltage gain DC to DC converter and two-level inverter. Due to the presence of high voltage gain feature, the VBTI topology can pump power from a lower DC voltage PV source in to the grid/load without using higher duties. Another important feature of VBTI is that it completely eliminate /suppress leakage current due to a common connection is shared between the negative terminal of PV source and grid neutral. In addition to that, the VBTI topology comprises only six controllable power switches to control the inverter which increases the reliability and decreases the cost of the system. Further, a simple level-shifted modulation strategy is introduced to control the VBTI. The design of the various power components of the VBTI and its main operating modes are discussed in detail. Further, the maximum efficiency of the VBTI assessed to be $\approx 95$%. The proposed VBTI topology is verified through MATLAB simulations for a 400VA grid-connected system. All the main results are presented in this paper. The experimental work for the PV fed grid-connected VBTI topology is underway.