Empirically Informed Approach to Output Filter Design for Wide Bandgap Motor Drive Systems

Wide band-gap (WBG) motor drives allow efficient high-frequency (HF) switching. Higher switching frequencies and faster switching transitions increase the challenges of electromagnetic interference (EMI). The existing literature proposes and analyses various filter designs for specific switched mode converters, but does not offer a consolidated design process for WBG drives, which require more attention to HF harmonics. In this paper, a method is proposed for WBG output filter design based on the empirically measured emission spectra of the drive, and the differential mode (DM) and common mode (CM) frequency response of the machine. The method is applied to the design of a filter with separate DM and CM EMC requirements.