Design and experimental evaluation of the flywheel system for power leveling

This paper introduces the performance of a power leveling system with a 3.0-MJ, 3315-r/min flywheel energy storage. In terms of cost reduction, this system uses low cost ball bearings and general purpose induction motor. Therefore, such a system configurations occurs large loss during standby mode. In order to overcome this problem, low loss design algorithm that focuses on the mechanical loss is applied to the design of the flywheel. As a result, the flywheel loss in the steady state consists of bearing loss of 28.3%, the copper loss of 22.5% for the induction motor. Moreover, charging and discharging efficiency are measured to evaluate the prototype flywheel system. From the analysis, it is confirmed that the charging efficiency is 75.4% and the discharging efficiency is 77.2%.