Reconfigurable DC/DC Converter for Efficiency and Reliability Optimization

In order to efficiently design power conditioning systems, operating conditions have to be considered. For instance, power converter design should take into account the intermittency of the renewable energy sources and the relatively low efficiency of some of their subsystems such as photovoltaic modules. This paper deals with dc-dc power converter design and aims to improve both reliability and efficiency. The approach adopted is based on a boost-based topology equipped with three MOSFETs in parallel. It uses a novel biobjective algorithm based on a biobjective function that optimizes the power converter efficiency and reliability. The proposed algorithm defines the number of MOSFETs to commutate in order to guarantee the best compromise between the converter efficiency and its reliability, depending on the available input power. The converter efficiency is determined by the power converter losses, calculated using the power device parameters and their junction temperature measurement as inputs. The converter reliability is calculated using its mean time between failures as assessed in the military handbook for reliability prediction of electronic equipment (MIL-HDBK-217F). Experimental results carried out on a 2.5 kW prototype demonstrate the effectiveness of the proposed system and the details from one day's photovoltaic power production are presented and discussed.