Examination of influence of periodic switching frequency modulation in dc/dc converters on power quality on a load

This paper presents examination of the influence of periodic switching frequency modulation in dc/dc converters on power quality on a load. The experiments are performed by the use of a buck converter which switching frequency is modulated by a sinusoidal modulating signal. The experimental results are also verified by simulations in PSpice. Analysis of the results reveals that there is increase in output voltage ripples as well as presence of appreciable modulating frequency harmonics in output voltage spectrum. Reasons why the side effects occur are found out and effective ways to reduce them are also suggested.