A Maximum Power Point Tracker of photovoltaic arrays for partial shading conditions

The Power vs. Voltage (P-V) characteristic of a photovoltaic (PV) array is characterized by the presence of multiple maxima under partial shading conditions. Out of these only one is the global maximum. Conventional Maximum Power Point Tracking (MPPT) techniques may fail to track the global maximum which results inconsiderable power loss. Therefore, special MPPT techniques are adopted for MPP tracking of PV arrays under partial shading conditions. This paper proposes a technique which tracks the MPP of the array under partial shading conditions. In the proposed technique the PV array is disconnected from the load for negligibly short period of time and is connected to an external capacitor. During the charging time of the capacitor, the proposed circuit tracks the global MPP. This circuit is easy to implement and shortens the time duration needed for scanning the P-V curve of the array.