الفهرس 
Solar Cell Equivalent Circuit
3.5. Results and AnalysisOnly 14 pages are availabe for public view
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Abstract
PV grid-connected systems become one of the most important and promising applications for solar energy. The interfacing of solar PV systems to the grid requires efficient control strategies for operation, control and Power Quality (PQ) improvement. In order to facilitate increasing the penetration levels of PV systems into the grid, Egypt has approved the Feed in Tariff systems (FIT),which aims to generate 2300 MW of PV system , also with the advancement of the technology and reduction in the cost of the power electronic devices, PV prices are rapidly decreasing. Due to these incentives, grid connected PV solar systems are growing rapidly and many new investments in this field are published, recently the Egyptian Ministry of Electricity and Renewable Energy have added 40 KW PV system connected to the grid over its building which will be the core of this thesis.
For grid-connected PV applications, two different topologies have been mostly studied worldwide, known as one-stage and two-stage PV systems. This thesis presents a comparative study with the basic characteristics for two types of topologies of a grid-tie PV system to show the overall system performance aspects including energy conversion efficiency, power quality, and maximum power point tracking “MPPT” accuracy.
In addition, the thesis presents the maximum real and reactive power control algorithm for 40 kW three-phase single-stage PV system using a fast approximation interpolation algorithm of MPPT. For synchronization with the grid, the phase locked loop technique (PLL) is used, which controls the system using dq0 transformation by converting the three-phase voltages into the d-q axes. This technique utilizes the filtered grid voltages and gives an improved results.
The operational objectives of PV system are fulfilled by many control schemes, MPPT control mode, a certain amount of real power control mode and the switching between them. During sunlight, the system sends active power to the grid and at the same time compensates some of the load reactive power. In case of lower isolation level, the inverter compensates some of the load reactive power. The advantage of this strategy is to get use of the inverter total capacity all day long.