Analysis of circuit and operation for DC–DC converter based on silicon carbide

Abstract

In this paper operating analysis of DC–DC converter is presented. Silicon Carbide based DC–DC converter is investigated. SiC power switches (i.e. MOSFETs and diodes) were used. Synchronous buck topology is applied for converter structure. The DC–DC converter mathematical model is also presented. The parameters of LC circuit were calculated using shown equations. Working conditions determine the values of output LC circuit (inductance and capacitance). Real power semiconductors are equipped in output and input capacitances. This feature may influence the generated input signal. Parasitic capacitances and inductances of the paths causes oscillations and voltage overshoots of the input PWM signal. To avoid such phenomenon, it is necessary to use a snubber circuit. This issue is also presented. The analysis of working conditions is presented for different switching frequencies. The size of passive components (LC) is compared for different operating points. Experimental tests results were presented. Waveforms of voltage and current signals were also shown.