Innovative measuring system for wear-out indication of high power IGBT modules

Power converter failures are a major issue in modern Wind turbines. One of the key elements of power converters for high power application is the IGBT modules. A test bench capable of performing an accelerated wear-out test through power cycling of IGBT modules has been made. In the test bench it is possible to stress the IGBT module in a real life working point, controlling the voltage, current and phase of the device under test. An analysis of failure mechanisms has been carried out, indicating that V_CE can be used as an sign of wear out of the IGBT module. Therefore an innovative measuring system for V_CE monitoring with an accuracy as low as a few mV has been implemented. The measurements on the IGBT in the test bench show that it is possible to monitor V_CE and use this as an indicator of wear-out.