Harmonic control of a converter

An arrangement for determining an operation parameter reference for controlling a generator side converter portion coupled to a generator of a wind turbine, the arrangement comprising:

• an arithmetic element configured to derive a fundamental current error by subtracting an unfiltered, generator output current from a sum of a fundamental current reference and at least one harmonic current reference;
• a fundamental current controller adapted to determine a fundamental operation parameter reference based on the fundamental current error;
• at least one other arithmetic element configured to derive at least one harmonic current error by subtracting a band pass filtered according to the harmonics, generator output current from the at least one harmonic current reference;
• at least one harmonic current controller configured to determine at least one harmonic operation parameter reference based on the harmonic current error;
• still another arithmetic element configured to determine the operation parameter reference as sum of the fundamental operation parameter reference and the at least one harmonic operation parameter reference.