Harmonics Mitigation in Grid-Connected Wind-Photovoltaic Hybrid Generation System

Hybrid PV-wind generation systems have increased significantly due to the rapid improvement in power electronics techniques. In this paper, three switching techniques for mitigating the output harmonics of a PV-wind hybrid generation system are investigated. The proposed hybrid system consists of a PV panel connected to the grid via a DC/DC converter and a 3 phase two-level inverter. The wind generator is a DFIG, its stator connected to the grid through a 3-phase transformer, while its rotor is connected to the grid via two converters. The paper investigates the performance of PV system with two types of dc-dc converters interfacing the PV panel to the grid inverter, and the harmonics injected to the grid when using three types of switching techniques for the inverter interfacing the hybrid system to the grid. Comparing the THD of the two dc-dc converters' output voltage and of grid voltage and current at the point of common connection for each type of inverter switching technique is presented for high insolation level and wide range of wind speeds.