Optimize Power Generation of Wind Energy Conversion

Energy conversion techniques are needed to generate electrical energy from non-conventional energy resources, which is easily available in form of wind and solar. In the direct drive i.e. gear less, wind energy conversion systems, the squirrel cage induction machine is operated as generator by maintaining the rotational speed higher than synchronous speed. The power conversion by wind turbine depends on the ratio of blade tip speed to the wind speed, known as tip speed ratio. Hence, for variable wind speed, the rotational speed of wind turbine is adjusted corresponding to optimum rotational speed, so that the tip speed ratio can be maintained at its optimum position at which wind turbine extracts maximum power from the available wind. The variable frequency control scheme requires consistently change in excitation voltage to maintain volt per hertz ratio constant at which the airgap flux remains constant at its rated value. This research work uses cycloconverter to supply excitation of the induction machine from the grid at variable voltage and frequency corresponding to optimum rotational speed in order to maintain maximum power extraction from the wind.