Maximum power extraction in grid connected DFIG using multilevel converter

The world aims at reducing emission by one fourth with the projected demand growth of four times of the present load. Significant effort made considerable money spent towards research and development to achieve this over ambitious target. This target cannot be achieved without a breakthrough in large scale integration of renewable energy into the grid successfully. Present grid and the renewable sources are not capable of meeting the stringent constraints. Wind energy is the most promising renewable among all other renewable and hence successful integration of wind to the grid will certainly a better option. Problem statement: In the conventional methods of wind energy conversion system it has various drawbacks such as common mode voltage production, harmonic contents more in the inverter side, fixed speed operation of wind turbine generator leads to less power extraction. Approach: Double fed induction generator (DFIG) technology allows extracting maximum energy from the wind, while operating in narrow speed ranges. It has the ability for power electronic converters to generate and absorb reactive power. A three-level diode clamped inverter is used in the proposed system. This analysis is based on reduction of the maximum common mode voltage levels of the rotor side converter which plays the key role in shaft voltage generation of the DFIG. Results: The proposed method results: voltage balancing of DC link capacitors and controlling of the active and reactive power delivered by the wind generator. The proposed DFIG with multilevel inverter aims at integrating winds farms even in weaker grid with improved Maximum power injection, Minimum harmonic issues with reduced impact on WTG. Conclusion: The proposed method, will improve the power quality which is delivered to the grid in terms of harmonic, inject the maximum power to the grid and improve the voltage profile.