Patent ID: 7868594

Claim:
A generating unit comprising: a generator having a stator with an axial opening therein, and a rotor comprising a rotor winding disposed and rotating within the axial opening, the rotor winding for producing a rotor rotary field magnetomotive force having a rotor rotary field frequency which is variable in relation to the rotor rotational frequency, wherein the width of a radial air gap between the rotor and an inside surface of the axial opening is between 1 cm and 8 cm; a drive that drives the rotor at a variable rotational frequency (n); a frequency converter electrically connected to the rotor winding; and a regulating device comprising: a recording element for measuring operational values of the generator, a calculating unit for simulating generator operation using measured operational values, a controller for generating a control signal responsive to the calculating unit, and a transmitter for transmitting the control signal to the frequency converter, wherein on the basis of the control signal the frequency converter adjusts the rotor rotary field frequency such that a constant stator rotary field frequency is maintained in the event of a variable rotor rotational frequency, the control signal determined according to the equation n =( f 1 +f 2 )/ p where f 1 is the stator rotary field frequency, f 2 is the rotor rotary field frequency, n is the variable rotational frequency of the rotor, and p is a number of generator poles.