The document analyzes the differential-mode electromagnetic interference noise of a single-phase boost power factor correction converter operating in critical current mode. It calculates the differential-mode noise spectra based on an EMI receiver model and determines the minimum corner frequencies for a differential-mode filter are determined by the maximum noises at 150 kHz. It also analyzes the relationship between inductor current ripple and differential-mode noise to identify operating conditions that produce the worst noise at 150 kHz, in order to design a differential-mode filter requiring only one worst-case noise spectrum.

1. INPUT DIFFERENTIAL-MODE EMI OF CRM BOOST PFC CONVERTER
ABSTRACT:
In this paper, the differential-mode (DM) electromagnetic interference (EMI) noise of a single-phase
boost power factor correction converter operating in critical current mode was analyzed. The DM noise
spectra are calculated based on the mathematical model of EMI receiver and the required corner frequencies
of DM filter are obtained. It can be seen that the minimum corner frequencies are determined by the
maximum noises at 150 kHz. With the relation between the magnitude of the inductor current ripple and the
DM noise, the characteristics of noise at 150 kHz are obtained by analyzing the current ripple magnitude at
150 kHz; thus, the worst conditions which have the maximum noise value are figured out. Meanwhile, the
maximum noises at 150 kHz for different input voltages are identical, so the DM filter can be designed
based on one worst spectrum at one input voltage without testing the spectra in other conditions.