An efficient maximum power point tracking algorithm for photovoltaic arrays under partial shading conditions

Various peaks in the Power vs. Voltage (P-V) characteristic curve of Photovoltaic (PV) arrays appear due to the effects of partial shading. Conventional Maximum Power Point Trackers (MPPTs) may be unable to track the Global Peak (GP) among the Local Peaks (LP). For tracking the GP under partial shading conditions it is important to develop special MPPTs. In commercially available MPPTs, blind scanning of the P-V curve is performed in order to find the GP. This type of scanning takes various seconds during which the array is not operated at the MPP. In this paper an MPPT algorithm is proposed which quickly takes the operating point of a PV to the GP under uniform and partial shading conditions. The presence of partial shading and the number of peaks is determined from the operating voltage of the modules. The voltage at which the peaks in the P-V curve are located is also determined from the module voltages.