Design and implemention of a three phase grid connected SiC solar inverter

Canver, Mehmet
In this research work a 30 kW grid connected voltage source three-phase inverter with SiC MOSFET module has been designed and implemented, in order to work with a phase-shifted full bridge (PSFB) maximum power point tracker (MPPT) converter, in such a way that these two converters compose a full system solution. The emergence of commercial SiC based power MOSFETs, which have short turnon and turn-off times, has enabled to increase switching frequency as compared to traditional Si based switching components. This circumstance was one the main motives of this thesis in the scopes of increasing the switching frequency, in order to reduce passive component volumes of inverter such as LCL filter and DC link capacitor volume, decreasing losses which leads to reduce the heat sink volume and having better efficiency. Designed and implemented inverter had been operated in the field with PSFB MPPT converter, energized by 23.75 kW total installed capacity solar arrays. Output characteristics had been investigated, and in the grid connected close loop mode various powers up to 22.32 kW had been transferred into grid. Inverter switching characteristics, drain-source voltage, unfiltered line current and zero voltage switching phenomenon were examined with the change of dead time and output line current. Total harmonic distortion had been recorded at various output powers, and a minimum THD value of 3.84% had been obtained at maximum output power of 22.32 kW. Experimental efficiency values was calculated from various recorded input and output powers. 98.55% peak efficiency at half of rated output power and 98% efficiency at peak output power had been obtained.
Citation Formats
M. Canver, “Design and implemention of a three phase grid connected SiC solar inverter,” M.S. - Master of Science, Middle East Technical University, 2018.