Patent ID: 6639370
Filing Date: 2003-10-28
Classification: H02J,H02P,Y02E

Abstract:
A speed control method for a flywheel energy storage system comprising:a flywheel for rotation about an axis, and supported by a bearing system inside an enclosed container that is maintained with an internal vacuum for reducing aerodynamic drag; a brushless motor and generator for accelerating and decelerating said flywheel for storing and retrieving energy; a current limiter that limits the acceleration current to said motor for accelerating said flywheel; a rate controller for digitally switching the acceleration current on and off to maintain the steady state speed within desired limits; whereby, said rate controller turns said acceleration current off when the flywheel speed is above the desired steady state speed upper limit, and then turns the acceleration current back on when the flywheel speed fails below the desired steady state speed lower limit.