Analysis and Mitigation of Conducted EMI Noise in SiC Fed Three-Phase Brushless DC Motor Drive

Abstract

The growth of brushless DC (BLDC) motor drives in industrial and residential applications emphasizes the need to effectively understand electromagnetic interference (EMI). This critical concern can significantly impact system performance and electromagnetic compatibility (EMC) requirements. This thesis addresses the nuanced challenges EMI poses in the context of a three-phase Silicon Carbide (SiC) fed BLdc motor drive, leveraging the advantages of trapezoidal back electromotive force (EMF) profiles. While BLDCmotorsoffersuperior attributes, including high torque-to-weight ratios, enhanced efficiency, and reduced acoustic noise, the integration of wide bandgap (WBG) power devices, such as SiC and Gallium Nitride (GaN), further elevates power density and efficiency. Despite the extensive discourse on EMI issues in induction motor drives, the research has paid limited attention to EMI challenges specific to trapezoidal flux BLdc motors. This thesis fills this gap by comprehensively analyzing common-mode (CM) noise in SiC-fed BLDC motor drives. Additionally, the study investigates the influence of various pulse-width modulation (PWM) schemes on CM noise and assesses their impact on the sizing requirements of CM chokes. Furthermore, the thesis explores the design and implementation of DC-side single-stage and two-stage EMI filters for motor drives. A novel approach is employed to reduce the footprint of the EMI filter printed circuit board (PCB), and minimize the volume of the filter enclosure of the EMI filter through an integrated magnetic methodology. In conclusion, this research contributes valuable insights into the intricate realm of EMI management in SiC-fed trapezoidal back EMF BLDC motor drives, offering practical solutions for enhancing EMC compliance while maximizing the advantages of WBG power devices in motor drive applications