Fatigue life prediction of IGBT module for metro vehicle traction converter based on traction calculation

Metro vehicles start and stop frequently, which leads to complex fluctuation of IGBT module's junction temperature and induces fatigue that causes the failure of IGBT module. In order to predict the fatigue life of IGBT module, theory and method for calculating train traction, loss, transient temperature and fatigue life were analyzed, and corresponding calculation modules were developed. Line 7 of Beijing Metro was studied, for which electrical parameters and loss were calculated under the rapidest traction strategy and AW2 load condition, the curve of heat pipe radiator thermal resistance versus vehicle velocity was obtained by numerical simulation, temperature curves of IGBT junction, IGBT case, diode junction, diode case and heat sink were calculated further, and the fatigue life of chips were obtained accordingly. Finally, the influence of the economic traction strategy, AW3 load condition, and the influence of ambient temperature on average chip temperature and fatigue damage was discussed.