Maximizing power harvest in a distributed photovoltaic system

Abstract

In a conventional grid-tied distributed photovoltaic (PV) system, individual power optimizers are used for modules connected in series to maximize energy harvest from each module. However each power optimizer lacks information on the string voltage and thus an inverter is designed to control the string voltage. This scheme is not guaranteed to have the maximum energy harvest in a PV system since the efficiency of an inverter is dependent not only on the string voltage but also on the string current. To improve the overall system efficiency, this paper presents a dual power optimization scheme for grid-tied distributed PV systems. It uses a power optimizer with feedback from the output of an inverter which controls the string voltage dynamically. We compare the proposed conversion system with the conventional distributed system in view of efficiency using simulation of commercial products.