Power enhancement of transformer less single-phase grid connected solar-wind energy conversion system for various environmental conditions

Abstract

Abstract This article presents the grid connected hybrid solar-wind energy conversion system (HSWECS) using the cascaded diode clamped multilevel inverter (CDCMLI). The advantage of CDCMLI over the conventional cascaded H-bridge multilevel inverter (CHBMLI) is that the power transfer capacity of the CDCMLI is doubled. The solar and wind energy conversion systems are connected individually to the DC-links of CDCMLI through the DC–DC converter which is used to get maximum power from solar and wind systems. Due to the fluctuating power supply by renewable sources, the isolated DC-links of separate inverters suffer from varying DC-link voltages. A control scheme is proposed which is capable of balancing these DC-link voltages under various power generation scenarios, extracting the maximum possible power from renewable energy sources (RES), and injecting it into the grid at near unity power factor. The proposed control also monitors the power quality of the injected current into the grid. Furthermore, it allows the system to be connected to the grid without any transformer. In addition, mathematical modeling of the CDCMLI has been presented. The performance of the system is analyzed with Matlab/Simulink and confirmed by a prototype model with dSpace 1104.