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

摘要

This article presents the grid connected hybridsolar-wind energy conversion system (HSWECS) using thecascaded diode clamped multilevel inverter (CDCMLI). Theadvantage of CDCMLI over the conventional cascaded Hbridgemultilevel inverter (CHBMLI) is that the powertransfer capacity of the CDCMLI is doubled. The solar andwind energy conversion systems are connected individuallyto the DC-links of CDCMLI through the DC–DC converterwhich is used to get maximum power from solar andwind systems. Due to the fluctuating power supply byrenewable sources, the isolated DC-links of separate inverterssuffer from varying DC-link voltages. A controlscheme is proposed which is capable of balancing theseDC-link voltages under various power generation scenarios,extracting the maximum possible power fromrenewable energy sources (RES), and injecting it into thegrid at near unity power factor. The proposed control alsomonitors the power quality of the injected current into thegrid. Furthermore, it allows the system to be connected tothe grid without any transformer. In addition, mathematicalmodeling of the CDCMLI has been presented. Theperformance of the system is analyzed with Matlab/Simulinkand confirmed by a prototype model with dSpace 1104.