Abstract:
The analysis, measurement, and attenuation of nonintrinsic differential-mode (NDM) and common-mode (CM) noise
in an induction motor (IM) drive are discussed in this paper.
In a voltage source inverter (VSI) fed drive, the NDM noise is
caused by the excitation of the CM capacitance paths by the
line to ground voltage. A measurement method at the input
side of IM is proposed to separate intrinsic differential-mode
(IDM), NDM, and CM noise from the total line current. It is
substantiated that the NDM noise constitutes a significant portion
of the measured DM noise. Hence, a passive sinusoidal output
electromagnetic interference (EMI) filter (PSOEF) is presented
to attenuate the NDM and CM noise. PSOEF is designed using
line inductor & capacitor with the same resonance frequency to
attenuate the NDM and CM noise. PSOEF has an advantage
of reduced size and number of CM components as compared
to conventional sinusoidal output EMI filter (CSOEF). The
designed PSOEF is presented with space vector pulse width
modulation (PWM) and CM voltage reduction PWM to analyze
the attenuation performance, circulating current, and filter loss.
The proposed measurement method and the design of PSOEF
are experimentally validated on a SiC VSI switching at 200 kHz.
