Maximum power point tracking for variable speed grid connected small wind turbine

This paper presents a method for harmonic mitigation and maximum power point tracking (MPPT) for a variable speed-grid connected 20 kW wind turbine. The wind energy conversion systems consist of permanent magnet synchronous generator (PMSG) driven by variable-speed 20 kW wind turbine. The output of the PMSG is connected to a single switch three-phase boost rectifier to generate DC voltage which feeds a current controlled inverter to interface the system with the electric utility. The single switch three-phase boost rectifier is an active power factor correction technique to maintain the power factor at the PMSG side to nearly unity and mitigate the PMSG current harmonic. To mitigate inverter output current and voltage harmonics, an LCL filter has been used. A complete analysis of the harmonic content has been done everywhere in the system. The results show that the proposed MPPT control strategy succeeded to track the maximum wind power irrespective of the wind speed. This strategy in presence of LCL filter achieved harmonic mitigation at the PMSG and inverter output sides.