Output ripple analysis of multiphase DC-DC converters

This paper presents an output ripple analysis of multiphase DC-DC power converters having an output LC filter. Analytical expressions for the output voltage ripple of two- and three-phase DC-DC power converters are derived. Influence of the coupling coefficient of the output filter inductor on the output ripple is investigated. Because the unique parameters of the LC filter cannot be determined solely based on the specified maximum output ripple, an additional criterion based on minimum energy storage is introduced. A comparative evaluation of single-phase, two-phase, and three-phase DC-DC power converters is presented. The validity of the proposed analysis method is verified by experimental results.