Model-based maximum power point tracking of an ageing solar PV module

Among the most common methods of Maximum Power Point Tracking (MPPT) are Perturb & Observe (P&O) and Incremental Conductance (InC) method. The major drawback of these approaches is that they cannot be used under rapid changing irradiation conditions as it takes them a long time to track the maximum power point (MPP). To overcome this drawback, a new method is proposed in the literature known as Model-Based Maximum Power Point Tracking (MB-MPPT). The conventional method uses environmental inputs such as irradiation and temperature to calculate the voltage at MPP. But the existing model-based approaches does not consider the impact of variation in series resistance of solar photovoltaic (PV) module on the voltage at maximum power point. These variations are caused due to degradation of the solar PV module over time. This paper proposes a new MB-MPPT technique, which takes into account the impact of PV module degradation on the maximum power point (MPP). The proposed method will help in tracking the exact MPP even for a degrading solar PV module. The necessary simulation results are presented.