Design of a flywheel energy storage system for wind power fluctuation suppression

Flywheel energy storage system (FESS) will be needed at different locations in the wind farm, which can suppress the wind power fluctuation and add value to wind energy. A FESS that can store up to 3.6 kWh of usable energy in 12 minutes at a maximum 24,000 r/m was designed. Multiple flywheels can be interconnected in an array, or matrix, to provide various megawatt-level power capacities for the wind farm. Based on ANSYS software, the finite element model of the flywheel was built to calculate the stress and strain field at different rotating speed. The maximum theoretical rotational speed and the peripheral velocity of the flywheel can be obtained. The flexible modes of the rim-hub-shaft system were also analyzed by ANSYS. The results indicated that the flywheel could run at the rated speed of 24,000 r/m safely. The running tests showed that the flywheel can smoothly pass through the two critical speeds, which was helpful for subsequent running tests.