Method for smoothing alternating electric current from a number of power generating units and wind power plant including a number of wind mills with variable rotational speed

摘要

A method and a wind power plant are provided for smoothing alternating electric current from a number of power generators. Generators are electrically connected to an electric network. Each power generator includes a transformer with pulse width modulation for converting direct current to pulse width modulated alternating current for feeding to the network. The time for feeding the pulses of the pulse width modulated alternating current is different for each generator in order to achieve a more even alternating current as a sum of respective outputs of alternating current from the generators.