Improvement in the efficiency of DC/DC power converters by controlling the switching frequency

In recent years DC/DC converters are becoming one of the most diffused power converter because of the spreading of renewables and storages. New topologies of DC/DC converters have been proposed to improve the energy efficiency. Anyway, in many applications the most diffused are always the traditional hard switching configurations for which some tricks are introduced in order to increase the efficiency. Usually, the switching frequency is considered a parameter to be kept low in order to reduce the losses. In this paper, the efficiency variation of a power converter with the switching frequency is deeply analyzed. From the reported analysis, it results that there is a particular frequency for which the power converter operates at its maximum efficiency. Moreover, for real converters, this frequency is in a range good also to ensure a good quality of the output voltage. In particular, the case of a SEPIC converter designed for PV application is taken into account and the optimal switching frequency is around 20 kHz. The proposed analytical approach has been verified by means of numerical results.