The three-phase cascaded VSI topology using coupled transformers for grid-connected PV applications

Abstract

In this paper, the three-phase cascaded VSI topology is proposed for PV grid-connection. The proposed control scheme is based on the classical control scheme, which is then extended to control the presented multilevel topology. Simulation is achieved by using SIMULINK environment. The obtained results proved that the proposed topology works well to improve the grid's voltages and currents quality. The control scheme succeed in keeping the grid currents in phase with the grid voltages, and the grid current's THD are within the acceptable range. To validate the effectiveness of the configuration and the accurate control, the proposed topology was built in a lab. Data acquisition and generation of gating signals to fire the switches were implemented on a MicroLabBox real-time controller. Experimental results are also provided to verify the viability of the proposed topology.