PERFORMANCE EVALUATION OF PHOTOVOLTAIC SYSTEM UNDER PARTIAL SHADING

Abstract

Global energy demand is increase rapidly. Major demand is met by fossil fuel. This increases the carbon foot print. So we move towards the renewable energy to reduce carbon foot print. With the increasing growth of renewable energy, photovoltaic (PV) systems are increasingly used to generate electrical energy from solar irradiation. In order to make the PV system can output the maximum power at all times, we can use the maximum power point tracking (MPPT) algorithm more often to reach the achievement that the system can work at the highest efficiency under the different atmosphere. Among all the MPPT methods, Incremental conductance method is used because of its highly accurate at partial shading condition also. It required two sensors, voltage and current. It response time is very fast. It mainly uses P-V characteristic curve to find MPP point. When the slope is zero, it is said that the system works at the MPP. Shading on PV array cause severe effect on obtaining maximum efficiency by reducing output power. The shading is caused by presence of cloud, shadow of nearby building, dust, damage of cell in the module etc. Under partial shading, it will make the P-V characteristics curve appear multiple peak point. It will lead the conventional P&O misjudge, and make the system work at local maximum power point (LMPP), not at global maximum power point (GMPP). So in this report first modelling of photovoltaic cell is done in MATLAB simulation according to current equation. Than output of boost converter is connect to inverter and further filtered output is connect to grid. PV power is supplied to grid. This PV cell is used in complete PV system simulation. Tracked the maximum power point under two different partial shaded PV cell. We have done the literature survey on different technique to track Global maximum power point under partial condition. Boost converter is used for matched input impedance to output impedance. Boost converter duty cycle is change to track the maximum power point with change the load. Pulses of inverter circuit is controlled by d-q axis or synchronous reference theory. Complete system is simulated in MATLAB and obtain desired output