A low-cost minimal-loss zero-maintenance
flywheel battery, to store
electric power from a DC power source by conversion to
kinetic energy, and regenerate
electric power as needed. Its vertical spin-axis rotor
assembly is supported axially by repelling annular permanent magnets, and is centered by
ceramic ball bearings which have axial preload that prevents vibration and augments axial rotor support. A regenerative multi-pole permanent-
magnet motor, controlled by its 2-phase
stator current, and connected by power and
signal conductors to power interface
electronics, is integrated within the
flywheel assembly, in a vacuum
enclosure supported by a self-leveling structure. Sinusoidal 2-phase
stator currents are controlled by high-frequency pulse-width-modulated H-bridge
power electronics that draw and regenerate controlled
DC current with minimal
ripple, responsive to respective 2-
phase rotation angle sensors, the DC power
voltage, and other settings. The
electronics includes logic and over-
voltage protection to prevent otherwise possible damaging current and
voltage.