This paper presents a real time measurement of on-state forward voltage and estimating the junction temperature for a high power IGBT module during a power converter operation. The power converter is realized as it can be used for a wind turbine system. The peak of the junction temperature is decreased at higher fundamental frequency due to change in on-state time from the change in output frequency. The junction temperature is estimated using the on-state collector-emitter voltage of the IGBT module. Lower output frequency is thermally a higher stressing zone for wind power converters, hence the low frequency range is considered from 6Hz to 20Hz; the corresponding on-state collector-emitter voltage and junction temperature are presented. The estimation of junction temperature is compared with finite element based thermal simulations. The peak temperatures at different frequencies are compared between measurement and simulation results. The measurement technique desinged to be implementable for field application.