Bidirectional flowthrough turboexpander

A method of operating an electric power generation system, the method comprising:

• during an expansion mode of operation of the electric power generation system:
• directing gas at a first pressure into a first gas conduit of a turboexpander generator,
• directing the gas at the first pressure into a flow wheel of the turboexpander generator,
• expanding the gas using the flow wheel,
• directing gas at a second, lower pressure through the turboexpander generator and out of a second gas conduit of the turboexpander generator, and
• generating electric power by rotation of the flow wheel from the expansion of the gas;
• and
• during a compression mode of operation of the electric power generation system:
• supplying alternating current to a stator coil of a stator of the turboexpander generator, the alternating current causing a permanent magnet rotor to rotate and causing the flow wheel to rotate,
• drawing gas into the second gas conduit and through the turboexpander generator based on the rotation of the flow wheel,
• compressing the gas by rotation of the flow wheel, and
• directing the compressed gas at a third pressure out of the first gas conduit of the turboexpander generator.

A turboexpander generator comprising:

• a rotor shaft comprising a node position, the node position defining a position of a node of a first bending mode of the rotor shaft;
• a flow wheel removably coupled to the rotor shaft at the node position, the flow wheel configured to:
• receive process gas at a first side of the flow wheel and rotate in response to expansion of the process gas flowing to a second side of the flow wheel, and
• compress process gas received at the second side of the flow wheel and direct compressed gas out of the first side of the flow wheel when the flow wheel is rotated in response to rotation of the rotor shaft by a rotating magnetic field, and
• wherein the flow wheel and the rotor shaft are configured to rotate together;
• and
• a stationary stator comprises a plurality of stator coils, the turboexpander generator to generate an alternating current upon rotation of the rotor shaft within the stator and to rotate the rotor upon energizing the stator coils with an alternating current;
• wherein rotation of the flow wheel causes gas to flow through the turboexpander generator.