Abstract: The DC-DC converters face the primary challenge of regulation, electromagnetic interference (EMI) and fault protection. This talk will highlight issues related to electromagnetic interference and fault protection. The design of a frequency dithering technique (FDT) to attenuate EMI noise and a fast and lossless shoot-through fault protection technique will be described in this talk. EMI attenuation is largely achieved through input-side EMI filters, which reduce power density but increase cost. The frequency dithering technique (FDT) is widely used to reduce filter size. However, the existing FDTs do not account for the 9 kHz Resolution Bandwidth (RBW) mandated by international standards. Additionally, the practicability of filter size reduction has not been validated. This paper proposes a non-uniform FDT with 15 switching frequencies, each spaced by 1 kHz, ranging from 32 to 46 kHz. The time duration of each switching frequency is adjusted to maximise EMI attenuation while minimising frequency variation. The persistence of switching frequencies during the dithering time is made non-uniform by accounting for the effects of a 9 kHz RBW, sidebands arising from FDT, and the noise floor, which have been largely neglected in the literature. Additionally, this paper validates the filter size reduction achieved by the proposed FDT. The proposed non-uniform FDT achieves EMI attenuation of up to 10 dB compared to single-frequency operation, resulting in a 58% reduction in filter volume. The proposed technique is experimentally validated on a 1 kW SiC-MOSFET-based DC-DC converter prototype. A lossless and fast shoot-through protection technique has been implemented by sensing the voltage drop across the parasitic inductance between the Kelvin and power-source terminals of a 4-leg SiC-MOSFET. This technique eliminates the need for additional sensing components, making the protection rugged and reliable. The developed protection scheme has been implemented in a gate driver board for an Electric Vehicle (EV) application. It is tested on a 1200V SiC-MOSFET full-bridge power module with a 730V DC bus. The experimental results show a fault-clearing time of 170 ns and a device current limited to 100A during a shoot-through fault at the rated DC bus voltage.

Event Details
Title: A Electromagnetic Interference (EMI) Attenuation Technique and A Shoot-Through Fault Protection Technique for SiC MOSFET-based DC-DC Converters
Date: March 03, 2026 at 3:00 PM
Venue: Google Meet (https://meet.google.com/gdk-tjzs-ucc)
Speaker: Mr. Koushik Ghosh (EE21D750)
Guide: Dr. Kamalesh Hatua
Type: PHD seminar

Updated: