Comparative evaluation of T-type topologies comprising standard and reverse-blocking IGBTs

For a Three-Level Three-phase T-type (3LTTC) rectifier and inverter of a high efficiency Uninterruptible Power Supply (UPS) with an output power of 20 kVA, most suitable semiconductor components are selected. For this purpose, this paper details conduction and switching loss models of T-type rectifiers and inverters, compares the total semiconductor losses achieved for RB-IGBTs and for different types of conventional IGBTs, and evaluates the improvements achieved if the Si rectifier diodes are replaced by SiC Schottky Barrier Diodes (SiC SBDs). The switching loss model is parameterized with measured switching losses. According to the results of this comparison, the rectifier preferably employs RB-IGBTs to realize the bi-directional switch and SiC SBDs for the rectifier diodes; switching frequencies up to 32.5 kHz are feasible for total semiconductor losses of the rectifier of 250W. For the inverter, a realization of the bi-directional switch using an anti-series connection of conventional IGBT/SiC SBD modules is found to be most suitable and facilitates a switching frequency of 19.7 kHz for maximum allowed losses of 250 W.