  The in-circuit differential-mode (DM) impedance at the AC input of a motor
drive system (MDS) serves as a key parameter to evaluate and estimate the DM
electromagnetic interference (EMI) noise caused by the switching of power
semiconductor devices in the MDS. This paper discusses a single-probe setup
(SPS) with frequency-domain measurement to extract the in-circuit DM impedance
of an MDS under its different operating modes. The advantages of the SPS are
its non-contact measurement and simple structure.
