Thermal stressing of power semiconductors in pulse‐controlled inverters by output currents of low fundamental frequency

The range of fluctuation of the junction temperature of power semiconductors in pulse-controlled inverters rises constantly as the fundamental frequency of the inverter output current falls. As a result, the maximum value of the junction temperature lies with low fundamental frequencies considerably above the mean value that is decisive for high fundamental frequeficie.I. This paper takes the example ofa GTO (gate-turn-off) pulse-controlled inverter to explain two processes for reducing the thermal stressing of the power semiconductors at low fundamental frequencies.