It is necessary to install flywheel energy storage (FES) system in distributed generation, which can improve the quality and the reliability of electric power. The proposed system is composed of four parts: flywheel, magnetic bearing, motor/generator, and power converter. A permanent magnet motor-generator is incorporated in a composite flywheel, running at high speed in a vacuum containment to minimize air friction losses. The flywheel is to be suspended on magnet bearings. A 3-phase, switch mode bridge inverter, driven by a pulse width modulation board, achieves the variable speed control for the motor/generator and the control for the DC bus voltage. The presentation will explain the schematics of the flywheel battery, control diagram, power electronics and motor/generator. The overall operation will be described.