Maximum Voltage Point Tracking for Partially-Shaded PV Modules

摘要

The output power of a photovoltaic (PV)string would decline drastically when a few of the PV modules in the string are subject to partial shading conditions (PSC). To restore part of power loss caused by the PSC, the output currents of the series PV modules should match to each other. In achieving this, a micro-converter is disposed at the terminal of each PV module and behaves like a current transformer. Once the best current of the PV string is determined, the micro-converter must contribute not only compatible current but as large terminal voltage as possible. An algorithm of maximum voltage point tracking (MVPT)is presented to maximize the micro-converter terminal voltage so that the operating point of the series PV modules can go toward respective maximum power points (MPP)and guarantee the power peak uniqueness. The experimental results show that the proposed MVPT for each PV module is autonomous and capable of tracking global maximum power point (GMPP)for a PV string.