SYSTEM AND METHOD FOR ENERGY STORAGE AND RETRIEVAL

Disclosed herein is a system comprising a generator/motor subsystem configured to interchangeably impart and receive mechanical force, a stiff DC bus, and power conditioning circuitry electrically connected between the generator/motor subsystem and the stiff DC bus. The power conditioning circuitry conditions electrical power received from the stiff DC bus to control the angular speed of a rotor of the generator/motor subsystem when imparting mechanical force, and to also condition electrical power generated for provision to the stiff DC bus by the generator/motor subsystem when receiving mechanical force. Also provided is a control subsystem automatically controlling excitation of the generator/motor subsystem in coordination with fluctuations in rotational speed of the generator/motor subsystem thereby to regulate input/output power of the generator/motor subsystem.