Effects of increasing switching frequency in frequency modulated power converters

The paper considers the effect of increasing switching frequency on a frequency modulated (FM) buck converter parameters: efficiency, output voltage ripples and electromagnetic interference (EMI) attenuations. The converter operating in continuous and discontinuous conduction modes (CCM and DCM respectively) is analyzed analytically, by simulations in Simulink and experimentally. The results obtained show that increasing switching frequency can significantly reduce the ripples (especially in DCM) and improve effectiveness of the use of FM to reduce EMI. Impact of increasing the switching frequency on efficiency of FM converter is also studied. It is found out that FM does not affect efficiency within the broad range of switching frequencies. The analysis provides useful data to improve the effectiveness of the use of FM in switchmode converters.