الفهرس 
Centralized invertersOnly 14 pages are availabe for public view
 |  | from | 155 |  |  |
| | | from | 155 | | |
Abstract
To reduce the problems of conventional energy sources, the recent energy generated from clean, environmentally friendly sources has become one of the major challenges for engineers and scientists. Among them, Photovoltaic (PV) applications have received a great attention in research to be one of the most efficient and effective solution to these conventional energy sources problems.
This study aims to design suitable control systems to regulate the output power and voltage for a PV-connected to grid system. A detailed mathematical model represents the whole system including PV array, DC-DC boost converter, inverter (DC-AC converter) and their control systems is simulated using MATLAB-SIMULINK software. The power system is tested for various disturbances such as 3-phase short circuit, one line outage and
variations in solar irradiation and temperature.
To extract the maximum power from the PV, the maximum power point tracking
(MPPT) techniques are utilized through conventional methods such as perturb and observe (P&O) method and incremental conductance (INC) method and also through artificial intelligent technique (Fuzzy logic system). Also, in order to operate at constant voltage suitable with the grid connection and for stabilizing the system performance when subjected to disturbances, suitable controllers are implemented where the control approach employs three control loops: The first control loop is used to control the duty cycle for MPPT achievement depending on irradiation factor and surface temperature of the PV system. The second control loop is used to regulate the magnitude of the inverter output voltage at a suitable value (Voltage Regulation) under various disturbances. The third control loop is
used to keep the inverter output reactive power at small value (unity power factor operation) to keep the current in phase with voltage. In this thesis, the results are obtained using PI controllers compared with Fuzzy logic control (FLC) systems.
It is concluded from the simulation results: in view of MPPT, the use of fuzzy logic (FL) method is better than the conventional methods. Also, the system performance using FLC systems is more stable, speedily, softly and less oscillation compared with PI controllers during and post prescribed disturbances.