Performance of a Magnetically Suspended Flywheel Energy Storage System

A magnetically suspended Open Core Composite Flywheel energy storage systems [OCCF] has been developed for spacecraft applications. The OCCF has been tested to 20,000 RPM where it has a total stored energy of 15.9 WH and an angular momentum of 54.8 N-m-s (40.4 Ib-ft-s). Motor current limitations, caused by power losses in the OCCF system, prevented testing to a higher speed. Experimental tests and theoretical analysis suggest that a significant power losse is caused by eddy currents in the magnetic bearing return rings. Our results suggest the losses can be reduced through the use of thin lamination in the magnetic bearing return ring.