The present invention relates to a method for operating a converter system of a wind turbine, wherein the converter system includes converter modules capable of converting electric power produced by a generator to electric power applicable to a utility grid. The converter modules include generator inverters and grid inverters. The method determines the enabling/disabling of the converter modules in response to a parameter related to the variable amount of electric power being produced by the generator. Advantages of the present invention are optimisation of power efficiency of the converter modules and improved reliability of the converter modules. Another advantage is the capability of fast enabling and disabling of the converter modules.