Hybrid Sensorless MPPT Algorithm for Detecting Fast Irradiation Changes and Partial Shading Conditions on PV Systems

Abstract

Higher solar energy potential from the Sun has increased the rate of development in solar power plants worldwide. The output power from the Photovoltaic (PV) panel is greatly influenced by the intensity of light falling on its surface. Because of non-linear characteristics of the PV array, a Maximum Power Point Tracking (MPPT) algorithm is employed to extract maximum power from the PV array. Uniform light on the modules in a PV array produces a single power peak on the P–V characteristic curve, in contrast to non-uniform shading on the PV array causes multiple peaks to occur on the PV curve. Conventional MPPT algorithms, Perturb and Observe (P&O), and Incremental Conductance (INC) perform well in tracking the maximum power during uniform conditions. But they lag in detecting the presence of partial shading on the PV modules. Generally, light sensors are placed at different locations along the PV array to identify the non-uniformity in the light incident on the array. This increases the cost and complicity of the system. Sensorless MPPT artificial intelligence algorithms detect the Global Maximum Power Point (GMPP) by regularly scanning the P–V characteristics curve to detect the multiple peaks. Fuzzy logic, neural networks, particle swarm optimization, and ripple correlation algorithms show improvement in tracking the GMPP. All the conventional algorithms are categorized under two methods, current-based and voltage-based control. None of the control algorithms have proved best among the two control strategies. In this chapter, a hybrid sensorless MPPT algorithm employing both voltage and current based control is proposed for identifying the presence of partial shading on the PV modules. The proposed method finds the GMPP with less number of iterations and the effectiveness of the algorithm is compared with conventional MPPT methods. Performance of the algorithm is evaluated by experimenting with severe changes in uniform and partial shading conditions and tested with a single-stage transfromerless grid-tied PV inverter.