Study of flywheel energy storage system for power leveling of wave power generation system

Wave energy is a clean and renewable energy resource, and various wave power generation systems are being studied. A direct-link wave power generation system has high power. However, its output fluctuates because the rotational speed of the generator depends on the wave motion. In this paper, a flywheel energy storage system is used to level the power fluctuations. Specifically, the design of the motor/generator (M/G) suitable for the flywheel energy storage system is examined. As a result, the 4-pole M/G for high-speed operation has the highest total efficiency in the M/G operating range. However, when considering mechanical loss, the 4-pole M/G for low-speed operation has higher total efficiency than does the 4-pole M/G for high-speed operation.