Conducted EMI analysis of a three-phase PWM rectifier

Abstract

Because of the strict electromagnetic interference (EMI) regulation, noises generated from high switching frequency converters need to be analyzed and suppressed by some methods. EMI noises in power converters are generally frequency related. This paper investigates the mechanisms of conducted EMI emissions associated with the typical three phases PWM rectifier system using frequency domain method. A simplified method for the calculation of Common-mode (DM) electromagnetic interference caused by the three-phase PWM rectifier is presented. Frequency domain noise current source has been represented first. The dominant high-frequency differential-mode current paths are identified later, the modeling principle of the paths has been explained at the same time, and this allows the noise spectrum to be predicted from knowledge of the component values. Theoretical predictions of EMI noises are verified by simulations in saber software through time domain and frequency domain analysis. © 2010 Springer-Verlag Berlin Heidelberg.