Importance

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Abstract

The invention relates to a method for operating a wind energy plant having a double-fed asynchronous machine, at least one inverter and at least one control device, wherein electrical energy is at least partly supplied into a grid via the inverter, the inverter comprises per phase at least one power semi-conductor module with at least two transistor circuits and at least two free-wheeling diodes and the inverter by using the control device is actuated at least at times via a pulse width modulation (PWM). The object, namely of providing a generic method for operating a wind energy plant in which an improved power output is effected even in the low-noise rotational speed range of the rotors, is achieved in that, at frequencies of the current to be impressed by the inverter on the machine side of less than 10 Hz, preferably less than 6 Hz, the switching-on duration and/or the switching frequency of the transistor circuits and/or of the free-wheeling diodes of the inverter are altered via the control device by taking their thermal heating into account.

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First Claim