Flywheel with switched coupling regulator

A flywheel energy storage system, comprising:

• an energy storage flywheel supported for rotation on a bearing system;
• a brushless motor and a brushless permanent magnet generator for accelerating and decelerating said flywheel for storing and retrieving energy, said generator having windings for a magnetic coupling for providing output power,
• an output regulator circuit for providing a DC voltage that is maintained within an allowable range for connected loads as the flywheel slows during discharging;
• said DC voltage is maintained within said allowable range by switching connections of numbers of windings of said magnetic coupling;
• said magnetic coupling is located in said generator of said flywheel system with said windings being the coils of said generator.

A method of generating electrical power, in a flywheel energy storage device, at an output voltage that is maintained within an allowable voltage range, comprising:

• energizing a brushless motor to accelerate a flywheel in said flywheel energy storage device to rotate and store energy in a form of rotational inertia;
• retrieving said stored energy in the form of electrical power by driving a brushless permanent magnet generator with said rotational inertia of said flywheel, said stored energy retrieval including generating a DC voltage in a multiplicity of windings of a magnetic coupling that provides output power, and maintaining said DC voltage within an allowable range for connected loads as the flywheel slows during discharging;
• said DC voltage is maintained within said allowable range by switching connections of said windings with an output regulator circuit to couple a number of said windings that produces said voltage within said allowable voltage range at a speed at which said flywheel is turning;
• said magnetic coupling is located in a generator of the flywheel system, with said windings being the coils of said generator.