A Novel Approach to Ensure Reliable EMI Performance: Identifying and Mitigating EMI Challenges in Fast Switching Power Converters

This study presents a novel approach to identify the underlying causes of failures caused by electromagnetic interference (EMI) in a Gallium Nitride (GaN)-based power converter. High switching frequencies power converters based on GaN or Silicon Carbide (SiC) can pose Electromagnetic Compatibility (EMC) challenges. Specifically, the converter under investigation consists of a Power Factor Correction (PFC) boost stage and a secondary buck stage, where the latter features a high frequency GaN switching transistor. The investigation of EMI problems resulting from the fast switching GaN components involved deactivating the primary PFC stage while keeping the filtering circuit and the secondary buck stage, a GaN device, active. Subsequently, the secondary stage was supplied with the 400V DC bus voltage, which it is designed to receive from the PFC stage. The findings of this study reveal the EMI-related challenges in fast-switching converters and present a methodical mitigation approach that can help in realizing EMI compliant designs. The proposed approach is relevant for identifying EMI challenges in other high-frequency power converters and can aid the designers in designing efficient and reliable power converters with improved EMC performance.