Development of Low Loss Active Magnetic Bearing for the Flywheel UPS

The flywheel for the uninterruptive power supply (UPS) is required to be lower mechanical loss during high-speed rotation. We developed low loss active magnetic bearing (AMB), and applied it to the prototype of the flywheel UPS. As a result, the AMB could support up to rated rotational speed at maximum load, and measured mechanicalloss was very low. In this paper, we mentioned the design, analysis and the results of rotating test.