Power generation unit and a method generating electric energy

A power generation unit including a turbine (3), a generator (6) driven by the turbine (3), an electric connection means (9-12) for connecting the generator (6) to an electrical network (2) and to turbine speed control means, wherein the turbine is exposed to a driving fluid of varying velocity, wherein the turbine speed control means is variable for substantially maintaining the turbine rpm and comprises electrical control means, wherein the generator (6) is a permanent magnet synchronous generator operating at a low load angle which is smaller than 12°, wherein the electrical connection means (9-12) includes a diode rectifier (9) for supplying a DC voltage and means (11, 12, 13) for regulating the DC-voltage-level, whereby the rotational speed of the turbine is controlled by the DC-voltage-level, and wherein the means for regulating the network DC-voltage-level includes an inverter with inverter-control means (27), a transformer (12) with ratio-control means and/or means (13) for changing the number of active windings turns in the generator.

A method for generating electric energy in which a turbine is exposed to a flowing fluid of varying velocity, the turbine drives a generator and the generator is connected to an electric network characterized by substantially maintaining the rpm of said turbine by providing the rotor of the generator with permanent magnets, operating the generator as a synchronous generator and at a low load angle that is smaller than 12°, providing a diode rectifier for supplying DC-voltage, regulating the DC-voltage-level and thereby electrically controlling the rotational spread of the turbine to be substantially constant, the DC-voltage-level being controlled by an inverter with inverter-control means, by a transformer with ratio-control means and/or by changing the number of active winding turns in the generator.