Method for operating a converter in a system for generating electrical energy

A method for operating a converter, via a control unit, in a system used for generating electrical energy, the system including a generator operatively connected to the converter which, in tum, is operatively connected to an energy supply grid, the frequency of a voltage generated by the generator being variable and a plurality of different switch positions being realizable with the converter, the method comprising:

• converting, in the control unit, voltages responsive to an output from the converter to respective d, q rotating coordinate system voltage trajectories, each being representative of a current voltage value and future voltage values;
• specifying a desired voltage value matching a frequency of a voltage of the energy supply grid;
• determining, from the d, q rotating coordinate system voltage trajectories, a closest trajectory having a current value closest to the desired voltage value and
• switching the converter in dependence on the closest trajectory, the switching being based upon a frequency of the voltage of the energy supply grid;
• wherein the specifying, the determining, and the switching are recomputed at predetermined time intervals.