Wind turbine with overload-capable converter system

A wind turbine for exchanging electrical power with an electrical supply grid at a grid connection point, comprising:

• a tower;
• a nacelle;
• a converter system for generating an electrical current or an electrical voltage;
• a controller for controlling the converter system and operating the converter system in a normal operating mode or in an overload operating mode;
• and
• a measuring device for detecting an overload situation in the electrical supply grid affecting the converter system, wherein the controller is configured to cause the operation of the converter system to change from the normal operating mode to the overload operating mode if the overload situation has been detected, wherein:
• the controller is configured to operate the converter system in the overload operating mode during the overload situation in the electrical supply grid such that an average switching frequency for generating an output current is reduced in comparison with the normal operating mode,
• a higher load for a predetermined maximum overload period is permitted on the converter system in the overload operating mode, and
• during the overload operating mode, an overtemperature is permitted for the maximum overload period in the converter system, and wherein the overtemperature is a temperature at which degradation occurs in the converter system or at which the converter system is prone to the degradation,
• the average switching frequency is reduced for the predetermined maximum overload period, wherein the maximum overload period is determined based on a thermal preload of the converter system that is based on a thermal capacity of the converter system or a thermal preload of components of the converter system that is based on a thermal capacity of the components of the converter system.

A controller for a converter system of a wind turbine, configured to:

• operate the converter system in a normal operating mode;
• in response to detecting an overload situation in an electrical supply grid affecting the converter system, change operation of the converter system from the normal operating mode to an overload operating mode;
• and
• operate the converter system in the overload operating mode during the overload situation in the electrical supply grid,
• wherein:
• an average switching frequency for generating an output current is reduced in the overload operating mode of the converter system in comparison with the normal operating mode,
• a higher load on the converter system is permitted in the overload operating mode for a maximum overload period,
• during the overload operating mode, an overtemperature is permitted for the maximum overload period in the converter system, and wherein the overtemperature is a temperature at which degradation occurs in the converter system or at which the converter system is prone to the degradation, and
• the average switching frequency is reduced for the maximum overload period, wherein the maximum overload period is determined based on a thermal preload of the converter system that is based on a thermal capacity of the converter system or a thermal preload of components of the converter system that is based on a thermal capacity of the components of the converter system.