CURRENT-VOLTAGE CURVE SCANNING METHOD FOR PHOTOVOLTAIC STRING, CONVERTER, AND SYSTEM

摘要

The present invention discloses a current-voltage curve scanning method for a photovoltaic string, a converter, and a system, including: obtaining output powers at initial scanning points of photovoltaic strings in a first group and a second group; controlling the output powers at the initial scan points of the photovoltaic strings in the first group to sequentially decrease, and controlling the output powers at the initial scan points of the photovoltaic strings in the second group to sequentially increase, where an initial scanning direction of each photovoltaic string in the first group is a direction in which an output voltage changes as an output power decreases and an initial scanning direction of each photovoltaic string in the second group is a direction in which an output voltage changes as an output power increases; performing scanning in the initial scanning direction starting from output voltages corresponding to the output powers at the initial scan points of the first group; and performing scanning in the initial scanning direction starting from output voltages corresponding to the output powers at the initial scan points of the second group; and output powers of the first group and the second group are kept to compensate each other during IV curve scanning. Therefore, scanning is simultaneously performed on all photovoltaic strings, instead of being performed in batches.