Hybrid power generation system using generator with variable mechanical coupling and methods of operating the same

A system comprising:

• a generator configured to be electrically coupled to a grid;
• a variable ratio transmission configured to mechanically couple the generator to a prime mover;
• a converter circuit configured to be coupled between the grid and an energy storage device;
• and
• a controller configured to operate the converter circuit to source or sink power in response to a change on the grid meeting a criterion.

A method comprising:

• mechanically coupling a prime mover to a generator to provide power to a grid;
• operating a converter circuit electrically coupled to the grid to source or sink power in response to a change on the grid meeting a criterion;
• mechanically decoupling the generator from the prime mover while maintaining an electrical coupling of the generator to the grid while providing power to the grid from the converter circuit;
• and
• providing current from the mechanically decoupled generator to the grid in response to a fault on the grid.

A method comprising:

• mechanically coupling a prime mover to a generator to provide power to a grid;
• varying a transmission ratio of the coupling between the prime mover and the generator responsive to a demand on the generator;
• and
• operating a converter circuit electrically coupled to the grid to source or sink power in response to a change on the grid meeting a criterion.