الفهرس 
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Abstract
In this thesis, Different types of renewable energy systems were studied. As for the exceptional merits of solar energy, the research work focuses on how energy pursuers can maximize their benefits from it. It also provides a thorough discussion on multiple researches the different types of AC and DC circuits, schemes and control algorithms used in the renewable energy domain. This study explores different modules; which are nonlinear loads, power generation units, neural network algorithms to obtain the maximum power generation, power exchange controllers, system stabilizers, Power. The research work also focuses on the features and characteristics of electric springs and their standalone microgrids. This Thesis is focus on the following.
First impact on the power generation is affected by the weather conditions in the photovoltaic systems. The present work is also concerning the sun irradiation and climate temperature state and its influence on the system values of volt and current generation. A simulation system is built by MATLAB Simulink which examined and tested. The Perturb & Observe maximum power point tracking system is considered too. The system runs under the state of irradiation values 200, 400, 600, 800 and 1000 kW/m2 at cell temperatures 25 ̊C and 40 C̊. The results are recorded and plotted to explain the effect of different values of irradiation and the cell temperatures on voltage and current and power.
Next, the Electrical Springs (ES), a new technology, is used to provide voltage and energy stability in a system and network powered by renewable energy sources, whether it is highly or poorly regulated and is self-contained. A method for managing the system for saving and regulating voltage and power generation is proposed. The power control scheme has provided correction of the system power parameter, voltage, current and power balance for critical loads, such as safety systems, as well as electric spring current characteristics of voltage and power stability. In this case, an addition of the battery energy storage BES module is necessary to ensure continued safe operation. Hence, the operation mode is safe by changing the operating load with the variable power of the PV panels. Some practical experiments are conducted to confirm the results and get used to the procedure for operating PV systems and to ensure their ability to be tested to withstand the electrical loads applied to them.
Finally, an experimental work of standalone PV system, are implement in the laboratory (Faculty of Technology and Education, Suez University, Suez, Egypt). The experimental study focuses on analysis the performance of PV system with and without energy storage during variation of environmental conditions.
One of the main goals of this thesis is to articulate the theoretical analysis and the operating principles of the ES with reactive power compensation. The present literature has left some gaps in the research, and this thesis aims to fill those gaps with understanding from the AC transmission system. The operating principles and behavior of the ES for voltage regulation axe formulated using mathematical analysis. A prototype of the ES has been developed, and the voltage regulation capability has validated and tested through simulation and experimental studies. Thus, it is demonstrated that the ES technology can be used for voltage regulation in isolated microgrids powered by the RES.
Another important contribution is the identification, evaluation, and analysis of the parameters which affect the performance of the ES. Through analytical reasoning various parameters that can affect the performance of the ES are identified. Through simulation and experimental studies, the performance of the ES, with respect to the identified parameters, has been evaluated and analyzed. This thesis gives significant insights on how performance of the ES depends on some but not all the system parameters. Also, the battery size reduction in a system, with the E, has been also evaluated.
The thesis is divided in seven chapters:
- Chapter 1. Introduction: Discusses the background about the using of PV systems, history and power demand in the world. Discussion about the Soler system and its main components.is presented Studying the MPPT systems with their effect of getting the maximum power in the PV plant, and finally the entering the electric spring for keeping the plant smooth work under the fluctuation of power coming from the sun are presented .
- Chapter 2. Literature Review: Discusses the literature review of the PV system and PV techniques for all researches published in the literature.
- Chapter 3. Electric Spring: Discusses the Electric Springs (ES), operation modes of ES, types of ES (DCES, ACES) and basic configuration, ES representation and equivalent circuits.
- Chapter 4. Performance Analysis for PV Modeling: Presents, theoretical work, MATLAB simulation for PV cell, experimental use load and climate temperature (25 and 40) and irradiation (200, 400, 600, 800, 1000) W/m2, ES and simulation the ES in simulation model of standalone PV system (with battery, without battery).
- Chapter 5. Simulation Result: Results first theoretical model as a single generation unit, and the second theoretical model, PV system with spring unit. The model results were taken as the results BESS with and, without BESS).
- Chapter 6. Experimental Work: Present the experimental set up off grid PV system, characteristic curves of the PV unit, experimental according the specification of standalone PV unit, curves (DC (with and without BESS)), (AC (with and without battery)), PV module and array (3 models connected in series) P-I , P-V curve.
- Chapter 7. Conclusion and Future Work: Explains the summary, conclusion and future work.
- The thesis contains of 109 references, three appendices and Arabic summary.