MPPT CONTROL FOR PV SYSTEM UNDER PARTIAL SHADING CONDITION WITH DIFFERENT ARRAY CONFIGURATIONS

Abstract

Day by day the energy demand is increasing worldwide and most of the energy demand is fulfilled by conventional energy resources. With the increasing energy demand the focus has been shifted to non-conventional energy resources like hydro, wind, solar etc. to meet the required demand as conventional energy sources are depleting fast and are causing environmental problems. Among, various available renewable energy sources, Solar PV systems due to its flexible installation, reliability, low operating cost and non-polluting operation is considered and used widely. Solar PV cell converts solar energy into electrical energy directly. The characteristics of PV array depends upon environmental factors like solar irradiation and temperature. To obtain the maximum available power from PV array it is essential to track maximum power point under varying environmental conditions. In the present work, a 1.049 kW standalone system is designed, modelled and analysed. The system consists of PV array and a boost converter with resistive load. For maximum power point tracking under varying atmospheric condition various MPPT algorithms viz P&O, InC and fuzzy logic controller are implemented and compared. It has been observed that fuzzy logic based MPPT algorithm gives better performance for changing irradiation condition. Along with varying environmental condition, Photovoltaic (PV) power generation faces an unescapable problem of partial shading condition (PSC). Under PSC all part of PV array doesn’t receive uniform irradiation which in turn reduces the output power generated. Furthermore, in partial shading conditions (PSCs) there are multiple peaks in the Power vs Voltage (P-V) characteristics out of which one is global maximum power point (GMPP) and others are local maximum power points. Maximum power point tracking algorithm is used for tracking the GMPP. Due to the existing problem in conventional MPPT to distinguish the global maximum power point in the P-V plot and as it is only being able to find out the first local maxima. The time taking process of finding the global point by practical swarm optimization (PSO) method, modified/advanced algorithm is needed. Consequently, a PSO P&O hybrid algorithm is proposed and implemented on PV system with PSC. The proposed algorithm is simulated in MATLAB/Simulink and it has been observed that proposed algorithm gives better performance. Along with using advanced MPPT tracker, various configurations of vi PV array viz. series parallel (SP) and total cross tied (TCT) configurations. Further, fill factor, shading loss, and mismatch loss has been calculated for various PV array configurations and it has been observed that TCT gives better performance under PSC.