Power cycling capabilities assessment of IGBT modules in wind power converter considering the wind turbulence effects

To accurately assess the reliability level of wind power converter for doubly fed induction generator (DFIG) system, an assessment methodology for power cycling capabilities of insulated gate bipolar transistor (IGBT) modules is investigated for wind power converter. First, power losses and junction temperatures calculation models of IGBT module are presented, the junction temperature calculation method for DFIG wind power converter is obtained. Then, performance characteristics of the junction temperatures with the wind turbine operation are analyzed in the rotor-side converter (RSC) and the grid-side converter (GSC), respectively. The effects of the fixed constant wind speed and wind turbulence speeds on the junction temperature of IGBT module in the RSC are compared. Furthermore, by using the rain-flow algorithm to extract the junction temperature fluctuations information considering the wind turbulence effects, an assessment methodology of the mean time to failure (MTTF) as an index of power cycling capabilities of IGBT modules for RSC is proposed. Finally, to demonstrate the presented assessment models, power converter of a 1.5MW DFIG wind turbine system is taken as an example, MTTF of IGBT modules on the RSC are evaluated and analyzed with the different annual average wind speed and wind turbulence intensity. The comparison results show that wind turbulence intensity has the important effects on the power cycling capabilities of wind power converter.