Electromagnetic Interference in Silicon Carbide DC-DC Converters

Abstract

A comparison of radiated noise for Silicon and Silicon Carbide converters is presented. SiC JBS diodes were used in this evaluation to enable fast switching times, whilst minimizing the transistor junction temperature. Radiated electromagnetic-interference measurements showed the highest noise signature for the SiC JFET and lowest for the SiC MOSFET. The negative gate voltage requirement of the SiC MOSFET introduces up to 6 dBµV increase in radiated noise, due to the induced current in the high frequency resonant stray loop in the negative power plane of the gate drive. The SiC JFET and MOSFET have shown overall converter efficiencies of 96% and 95.5% respectively. This efficiency shows only a weak frequency dependence, in contrast to the CoolMOS/SiC JBS diode combination which demonstrated an efficiency drop from 95% to 92.5% when increasing the frequency from 100kHz to 250kHz.

Wide Bandgap Technologies and Their Implications on Miniaturizing Power Electronic Systems

“…The cost of higher switching frequencies is that more elements of the system begin to function as antennas. Bogonez-Franco and Sendra [46] and Mostaghimi [47] show that replacing a Si switch or freewheeling diode with a SiC device on power converter printed circuit boards directly impacts the radiated emissions. The first and simplest method of reducing radiated emissions is to minimize path lengths by placing components as close as possible to the switching devices [48].…”

Novel wide bandgap semiconductor material based on ternary carbides - An investigation into Al4SiC4

“…WBG materials also look to be able to produce devices that are smaller and more efficient along with having the ability to withstand harsh environments. Research in WBG materials estimates that replacing silicon with SiC or GaN can enhance many power electronic device metrics such as the increased DC-DC conversion efficiency from 85% to 99% [7,8], AC to DC from 85% to 98% [9], and to optimize the efficiency of DC to AC from 96% to 99% [10]. Not only do power electronics benefit from the properties of WBG materials, but also RF applications.…”