Low-Cost Single-Phase Multi-Level Inverter for Grid-Tie PV System Applications

Most renewable energy sources such as photovoltaic, fuel cell, and wind energy generate their power at very low dc voltage which is not suitable for grid connection directly without using transformer. This paper proposes a new high efficient PV grid-tie system. The proposed system consists of a single-phase five-level inverter linked with DC-DC multilevel boost converter used to extract the maximum power from the PV arrays. The proposed inverter has the advantages of using less number of components, low cost, less harmonics, and high efficiency compared to the conventional one. Simulation and experimental results have been done to demonstrate the validity of the system. The laboratory prototype is controlled by using dspace-1103.