الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 219 |  |  |
| | | from | 219 | | |
Abstract
Building a photovoltaic plant that generates a megawatt was not visible, to the most, until the late 90’s. Now, ideas and opportunities for producing Terawatts photovoltaic systems are under discussions. The work described in this thesis coincides with the present worldwide developments in up rating the photovoltaic plants and search for new renewable energy sources to substitute for the lack of conventional sources. The work described in this thesis is a part of a project, initiated in the Department of Electrical Engineering, Sebin El-Kom, with the objective of studying, theoretically and experimentally, the characteristics of photovoltaic systems and evaluating the performance of various AC and DC loads when fed from photovoltaic systems. Modeling and simulation of photovoltaic systems are detailed and a parametric study is presented, showing the effects of cell parameters on the photovoltaic system performance. The installation of a photovoltaic array comprising six monocrystalline modules based on irradiation measurements is described. Due to manufacturing techniques of photovoltaic modules and lack of cell parameter, the thesis presented a parameter estimation technique using the direct search optimization method. The technique is based on reshaping the simulation results to fit experimental measurements. The results show a good agreement between the simulated power-voltage characteristics and real measurements. The power-voltage characteristics are obtained at different irradiation levels and loading conditions of photovoltaic systems are discussed, leading to the fact that photovoltaic systems should operate at the maximum power point (MPP) for efficient and economical Abstract 2 operation of such systems. An assessment of DC-DC converters used with photovoltaic systems is presented and a suitable DC-DC converter is recommended. The design of maximum power point trackers is reviewed and discussed. A Voltage- Based maximum power point (MPP) tracker is proposed, designed and assessed by computer simulation. The proposed MPP tracker avoids drawbacks of previous Voltage- Based MPP trackers. The performance of the proposed MPP trackers is presented in a comparative form with another tracker designed based on the most popular MPP design technique and a superior performance of the new tracker is observed under normal and changeable weather conditions. Two trackers are tested experimentally using a DSPbased photovoltaic system and good agreements between theoretical and experimental results are shown. Indirect field oriented control (FOC) for a three-phase induction motor fed from a photovoltaic power source is presented. The performance of the motor is extensively assessed by computer simulation and the results are discussed. The FOC scheme is implemented experimentally using a DSP-based PV system and results are obtained under different conditions. The theoretical and experimental results are presented and discussed, illustrating successful implementation of FOC on induction motors fed from photovoltaic sources. The techniques and algorithms developed in the thesis are of prime importance to power system engineers forming a useful based for the development and utilization of photovoltaic systems.