Detailed Oscillation Analysis and Parameter Selection Principle for Boost PFC Converter With RC Snubber Operated in DCM

The parasitic parameters of a boost power factor correction converter lead to input current distortion when the converter operates in discontinuous conduction mode, and using an RC snubber is a simple and effective way to suppress the parasitic oscillation. The effect of the RC snubber on the parasitic oscillation is analyzed in detail, and three different forms of the characteristic roots are obtained according to different RC values. The optimal RC values and their relationship between the inductance and parasitic capacitance are figured out, which can achieve a lowest total harmonic distortion. A 1-kW prototype has been built and tested at low power and the experimental waveforms and data are presented to validate the theoretical analysis.