A high efficiency motor/generator for magnetically suspended flywheel energy storage system

The authors discuss the theory and design of a brushless direct current motor for use in a flywheel energy storage system for spacecraft. The motor design is optimized for a nominal 4.5 in outside diameter operating within a speed range of 33000-66000 revolutions per minute with a 140 V maximum supply voltage. The equations which govern the motor´s operation are used to compute a series of acceptable design parameter combinations for ideal operational Engineering trade-offs are then performed to minimize the irrecoverable energy loss while remaining within the design constraint boundaries. A final integrated structural design whose features allow it to be incorporated with the 500 Wh magnetically suspended flywheel is presented