System and method for maximizing power output of photovoltaic strings

摘要

A PV system includes a plurality of PV strings each having an optimal string voltage at which a string output power is maximized. The PV strings are connected to a DC link in a parallel arrangement such that each PV strings operates at a variable DC link voltage. A PV inverter is connected to the DC link to receive a DC output, with the PV inverter controlling the DC link voltage. Delta DC/DC converters are connected to the PV strings, with each DC/DC converter receiving the DC link voltage from the DC link and providing a tuning voltage to the DC link voltage at which its respective PV string operates in order to bring the string voltage for that PV string to its optimal string voltage. The tuning voltage of each delta DC/DC converter is the difference between the DC link voltage and a respective optimal string voltage.

主权项

1. A photovoltaic (PV) system comprising:
a plurality of PV strings configured to generate a string output power responsive to received solar irradiation, each of the plurality of PV strings having an optimal string voltage at which a string output power is maximized; a DC link connected to the plurality of PV strings, wherein the plurality of PV strings are connected to the DC link in a parallel arrangement such that each of the plurality of PV strings operates at a variable DC link voltage; a PV inverter electrically connected to the DC link to receive a DC output therefrom, the PV inverter configured to control the DC link voltage; and a plurality of delta DC/DC converters electrically connected to the plurality of PV strings such that each of the plurality of delta DC/DC converter is connected to at least one PV string, wherein each DC/DC converter receives the DC link voltage from the DC link and is configured to provide a tuning voltage to the DC link voltage at which its respective PV string operates in order to bring the string voltage for that PV string to its optimal string voltage, the tuning voltage of each delta DC/DC converter being a difference between the DC link voltage and a respective optimal string voltage.