A Novel MPPT Technique based on an Image of PV Modules
The main source of power losses in PV systems is caused by partial shading, which occurs when the PV units in a PV system do not all receive the same irradiance. Unlike PV systems receiving homogeneous conditions in which a single power peak exists in the output power curve, partially shaded PV systems may exhibit several power peaks. Therefore, tracking the global maximum power point GMPP in partially shaded systems can be challenging because the conventional maximum power point tracking MPPT algorithms (such as perturb and observe P&O, incremental conductance, etc.) can get trapped in a local power peak and thus miss the true GMPP. The available MPPT methods that are able to track the GMPP require periodic scanning of the PV curve, which disturbs the operation of the system and causes power losses because it forces the PV system to operate on non-maximum power points.
A new MPPT technique is presented in this seminar that is distinguished by its ability to find the GMPP without the need for periodic curve scanning. The proposed method utilizes the mathematical model of the PV module, as well as the irradiances received by its PV cells, to analytically calculate the location of the GMPP. The required irradiances are innovatively estimated using an image of the PV module captured by an optical camera. The proposed method is also combined with the P&O method to compensate for errors in the model or irradiance estimation. Experimental verifications are conducted to validate the effectiveness of the proposed MPPT method under various shading scenarios.