Extended T-type Inverter
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Warsaw University of Technology
Jacek Rąbkowski   

Warsaw University of Technology, ul. Koszykowa 75, 00-662 Warsaw, Poland
Power Electronics and Drives 2018;3 (38)
This paper presents a new concept of a power electronic converter – the extended T-type (eT) inverter, which is a combination of a three-phase inverter and a three-level dc/dc converter. Novel converter shows better performance than a comparable system composed of two converters: a T-type inverter and a boost converter. At first, the three-level dc/dc converter is able to boost the input voltage but also impacts on the neutral point potential. Operation prin-ciples of the eT inverter are explained and simulation study of the SiC-based 6 kVA system is presented in this paper. Presented results shows a serious reduction of the DC-link capacitors and the input inductor. Furthermore, suitable SiC power semiconductor devices are selected and power losses are estimated using Saber software in reference to a comparative T-type inverter. According to simulations, the 50 kHz/6 kVA inverter feed from the low voltage (250V) shows below 2,5 % of power losses with suggested SiC MOSFETs and Schottky diodes. Finally, a 6 kVA laboratory model was designed, built and tested. Conducted measurements show that despite low capacitance (2 x 30 µF/450 V) the neutral point potential is balanced and observed efficiency of the inverter is around 96%.
ISSN (print):2451-0262