Optimization of switching losses and EMI in a Cuk converter

Switching mode power supplies are significant sources of electromagnetic disturbances, especially conducted EMI, due to the high current and voltage derivatives caused by the high frequencies used today in order to reduce the size of electromagnetic and capacitive elements. The present paper deals with a specific design technique aimed to reduce conducted EMI in Cuk power converters using power MOSFETs. The goal of such a design approach is to achieve an optimal compromise between power losses and electromagnetic emissions by working on the signals driving the switching device. Theoretical development of the design technique is reported as well as experimental measurements of conducted EMI on a 250 W 100 kHz Cuk power converter.