The three-level inverter is a cost-effective solution because a single module replaces the two modules used for a standard two-level half-bridge topology. The topology for the three-level inverter is realised by the series connection of IGBTs with which it is possible to obtain higher reverse IGBT blocking voltages. By merely connecting three of these modules, it is possible to achieve a complete three-phase three-level inverter topology with maximised electrical and thermal efficiency. The sinusoidal output waveform makes it possible to reduce the size and complexity of output filters. A reduction of 25 percent is achieved in both overall dimensions and cost, compared to a standard two-level half-bridge inverter.
Current ratings available at present are from 20A to 150A employing 600V IGBT silicon. Modules operate with input power from 5kVA to 80KVA in power supply applications. The IGBTs for three-level inverters are available in two housings: SEMITOP 3 (55x31x12mm) for modules with current ratings from 20A to 50A and SEMITOP 4 (60x55x12mm) for modules with current ratings from 75A to 150A.
SEMITOP is an isolated power module that can be quickly assembled into a complex circuit thanks to its base plate free technology, with only one mounting screw needed to fix to the heat sink before being automatically soldered to the PCB. The pressure contact technology and single mounting screw guarantee low thermal resistance and the mechanical stress-free design ensures high power cycling capability.