DC Integration of Residential Photovoltaic Systems: A Survey

PV systems are penetrating the energy generation market rapidly and their output strongly depends on environmental conditions. To maximize the energy yield, the utilization of power electronic converters with maximum power tracking function is mandatory. Typically, the dc voltage generated by PV is fed into the ac grid using an dc-ac inverter. On the other hand, most modern loads, from small to large ones, are based on dc. Hence, wide adoption of residential dc microgrids (RDC mu Gs) based on PV energy generation becomes a trend that is following the developments in modern energy-efficient buildings. This paper targets power converters for the integration of PV systems into RDC mu Gs. It considers two main classes: high step-up converters for PV module-level (parallel optimizer) applications and non-isolated buck-boost converters for the PV string (series optimizer) applications. Due to the importance of the PV topic, a significant number of topologies have been introduced in the literature. However, only selected solutions attracted the interest of the industry. This review paper considers PV converters used in the industry or demonstrated in academic publications at a high technology readiness level with comprehensive experimental justification. This allows us to focus this review on the most valuable solutions and to provide a guide for both industry and academic readers. In the end, future trends in industrial PV systems and associated power converters are discussed.