Analytical Modeling of 9-150 kHz EMI in Three-Phase Active Rectifiers

In recent years, new challenging issues have been raised due to interaction among power electronic converters and other electronic devices such as mains communication systems connected to the distribution network within a 9-150 kHz frequency range. Since there is a lack of a general standard and also a fundamental study within this new frequency range, it is necessary to investigate power converter frequency behavior within 9-150 kHz. It not only enables the possibility of characterizing power converters behavior but also provides a suitable indication of designing proper Electromagnetic Interference (EMI) filters. Moreover, there are no fundamental studies and general standards despite some reported EMI noise issues in this frequency range. Therefore, it is necessary to investigate the power converter frequency behavior within this new frequency range, providing a guideline to design proper EMI filters. This paper proposes an analytical time-frequency domain approach for modeling Differential Mode (DM) EMI noise of three-phase active rectifiers within the 9-150 kHz frequency range. To develop an analytical frequency-domain approach, the switching function model of the converter is defined using a double Fourier analysis method, including its input estimated impedance model. Furthermore, the equivalent circuit model includes Line Impedance Stabilization Network (LISN) circuit, and EMI receiver due to EMI standard requirement. A 9 kW three-phase AC to DC grid-connected converter prototype is used to validate the proposed EMI modeling approach. The analytical approach is shown to successfully predict EMI emission within the 9-150 kHz frequency range with an error of 1.2 dB or less at most frequency ranges.