Harmonic reduction methods for wind energy conversion systems: A review

World is moving slowly but steadily towards renewable energy because these are inexhaustible, pollution free and available abundantly. Wind energy source is one of the prominently renewable energy sources as wind would never dies till the existence of the universe. Previously we were using fixed speed wind turbines in wind energy conversion system (WECS), but due to some disadvantage of fixed speed wind turbine system, we moved to variable speed wind turbine system. Variable speed wind turbine uses power electronic converter in order to extract maximum power, but power electronic converter are a source of harmonics due to its switching action. This harmonic in the voltage and current of wind power deteriorates the power quality of wind power. So to reduce the harmonic in variable speed WECS, several methods have been proposed in the last so many years to reduce the harmonic problem arising due to variable speed WECS. This paper presents a review of some of the harmonic mitigation technique that presents in the last many years in order to increase of the power quality.