الفهرس | Only 14 pages are availabe for public view |
Abstract Satellites need a source of power throughout their missions to help them remain operation during mission time. The supplied power of these satellites, provided primarily by solar arrays, should have high efficiency and low weight in order to meet stringent design constraints and reduce the cost. Power conversion from these arrays is required to provide robust and reliable conversion which performs optimally in varying conditions of temperature and solar flux as well as aging factors. Since the function of these arrays is to deliver power, one of the principle factors in achieving maximum power output from an array is tracking and holding its maximum-power point. This point, which varies with temperature and pressure in the space, irradiation and loading conditions, must be continuously viewed in order to react to rapid changes. Over the past decades many maximum power point tracking algorithms have been published. The first objective of this thesis is to study and analyze them. The three algorithms that where found most suitable for photovoltaic (PV) in space applications which are perturb and observe (P&O), incremental conductance (IncCon) and fuzzy logic control (FLC). These were selected for further analysis using a prototyping PV system with a boost DC-DC converter using Microchip® PIC18F452 microcontroller to execute these algorithms. Some modifications to the FLC algorithm are proposed, which facilitate the calculations and enhance the performance of the control algorithm. The three algorithms tested under different conditions, and the test results are analysed and compared. The results show that the proposed fuzzy logic control algorithm can give better performance than perturbation and observation and incremental conductance algorithms. |