Investigation of Conducted Electromagnetic Interference of Three-Level SiC Power Module

In this paper, a 1200-V/200-A three-level silicon carbide (SiC) power module with neutral point clamped (NPC) topology has been investigated in terms of electromagnetic interference (EMI). Compared with traditional two-level SiC modules, the three-level module can effectively alleviate voltage stress of the device, and ensure lower spectrum amplitude of the output terminal voltage below resonance frequency. However, the three-level module presents higher spectrum amplitude in high-frequency (HF) ranges (above 10 MHz) due to the aggravated switching ringings. As a result, RC snubber circuit is required to mitigate such ringings and reduce spectrum amplitude for three-level module. According to relative experimental results, it can be figured out that the three-level NPC power module combined with RC snubber circuit can suppress switching ringings, which is critical for reducing the level of conducted EMI.