Present trends and future prospects of asynchronous machines in renewable energy systems

To fulfil the yearning of the majority population around the world and the need for environmental concerned energy conservation made renewable energy system (RES) as much obligatory among other energy systems. The asynchronous machines are particularly used in wind and hydro for creating more opportunities and challenges to have a control over them in order to create a stabilized RES. This paper extensively reviews on various types of asynchronous machines under different operating speeds and the existing control techniques deployed over them to aid a stabilized RES. In this context an analysis on the gradual development of machines and the role of power electronics over them to adopt with the up to date technology has been carried out. Additional benefits in terms of energy efficiency comparison between the synchronous and asynchronous machines in variable speed operation has also been premeditated. To a greater extent the paper advents the topical inclinations and imminent directions on asynchronous machines that can widely contribute to the growth of RES.