EMI Attenuation in a DC-DC Buck Converter Using GaN HEMT

A dc-dc buck converter using gallium nitride (GaN) high electron mobility transistors (HEMTs) is experimentally investigated at the discontinuous-current-mode (DCM) and the triangular-current-mode (TCM) operations. The objective of this article is to specify the power conversion efficiency and attenuation of common-mode (CM) and differential-mode (DM) noise voltage, measured at the line impedance stabilization network (LISN) for the compared control strategies. Zero-voltage switching achieved for the TCM operation improves efficiency with reference to the DCM operation. However, significant attenuation of electromagnetic interference (EMI) spectra is obtained for TCM operation with capacitive snubber. Sizing of capacitor snubber dependent on parasitic inductances of the commutation circuit and rapid switching of GaN HEMTs are illustrated.