A Status Monitoring Method for Multi-parallel Choppers in Wind Turbine Converters

The multi-parallel chopper system is commonly used in modern MW-level wind turbine converters. Even though the chopper is usually considered as robust and reliable, the semiconductor module can suffer critical junction temperature in extreme fault ride through (FRT) events. This paper proposes a method to monitor and identify if the individual chopper is functioning, degraded, or failed by means of collecting and comparing the parallel semiconductors' temperatures during FRT events. A simulation model is created in PLCES, the accuracy of which is further validated by a dedicated experimental setup including an infrared camera. The proposed method is verified by PLECS simulations.