A novel method to compare converters for PV applications based on energy efficiency

Abstract

A novel method for selecting the most suitable converter for photovoltaic (PV) panels is given in this paper. The innovations reside on the analysis of energy efficiency; where, in addition to the converter power efficiency, the extraction power efficiency and the energy power distribution are considered. It is shown that the conventional method of selecting the converter based on its power efficiency is not always accurate in terms of the harvested energy. Two interleaved flyback converters with different designs and control and switching strategies are compared; one is controlled by duty cycle and the other is controlled by frequency. The result of the conventional method of comparison suggests that the design controlled by frequency is about 2 % more efficient that the design controlled by duty cycle. However, the proposed method of the comparison shows that the design controlled by duty cycle delivers to the load 12.5 MJ more per year, that represents a 1.9 % increase in energy efficiency, showing that the conventional method is not the best in terms of the harvested energy.