Abstract : The expansion of photovoltaic (PV) systems has revealed the presence of losses due to module coupling, better known as mismatch losses, depriving producers from additional and available electric energy. This thesis aims to better understand the causes and mechanisms of mismatch losses in grid-connected installations. Two solutions to reduce these losses are proposed, studied, and compared. The modelling of PV systems submitted to shade for power production forecasts will be presented and validated experimentally. The first solution proposed consists in modifying the connection scheme of the array. Then, alternative grid-connected PV system topologies aiming to reduce module mismatch through power electronic device implementation within the solar array will be studied. This work will conclude with a global comparison of the proposed solutions based on the study of residential and commercial-sized installations.