Reliable, efficient and fault tolerant power converter for grid-connected PV system

In this paper, a grid-connected PV system for a three phase renewable energy integration applications is investigated. Efficient power topology and control algorithm designs aiming to optimize the performances of this power conditioning system are presented. The proposed two stage installation aims to optimize its reliability and efficiency and to be fault tolerant to one power switch fault. The first is a DC/DC conversion stage based on two boost reconfigurable converters controlled with a Distributed MPPT algorithm. The efficiency of each of the converter configuration and its MTBF (Mean Time Between Failure) are calculated using the Reliability theory and the MIL-HDBK-217F standards. Thanks to an appropriate bi-objective function optimization, the DC/DC configuration that maximize both its efficiency and reliability is chosen. Finally, we propose to integrate a fault tolerant 3 level NPC converter for the second power stage of the proposed grid-connected PV system. Simulation results carried out with a 10-kVA system are presented and discussed.