NOVELTY - The power generation apparatus (1) has a hydro turbine (2), an asynchronous generator (3) and an AC-AC converter (4). The AC-AC converter has a first port (41) that is electrically connected with a stator winding (33) and a second port (42) that is electrically connectable with an electric power distribution grid (5). The AC-AC converter is capable of transmitting electric power from the asynchronous generator towards the electric power distribution grid, and vice versa. The AC-AC converter is of the active front end type.    USE - Hydroelectric power generation apparatus for use in small hydroelectric power generation plants, particularly of the fluent water type. Ca be used in small hydroelectric power generation plants having a nominal power lower than 10000 kilowatt and used in country-side or mountain regions.    ADVANTAGE - The asynchronous generator is more robust with respect to traditional synchronous generators, requiring a reduced number of maintenance interventions. The asynchronous generator can be operated over a wide operating speed range and is quite easy to use, without the need of arranging dedicated synchronization devices or relays. The hydroelectric power generation apparatus is flexible in operation and is capable of properly functioning even when relevant variations in operating regime of the turbine, e.g. due to seasonal variations of the available water to actuate the turbine. The hydroelectric power generation apparatus has a relatively simple structure that can be easily installed on the field, at relatively low costs. The hydroelectric power generation apparatus is of relatively easy industrial production, at competitive costs with respect to traditional hydroelectric power generation systems.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic block diagram of the hydroelectric power generation apparatus.    Power generation apparatus (1)    Hydro turbine (2)    Asynchronous generator (3)    AC-AC converter (4)    Electric power distribution grid (5)    Stator winding (33)    First port (41)    Second port (42)