Summary: | 碩士 === 國立勤益科技大學 === 電機工程系 === 100 === Due to the severity of the global energy crisis and environmental pollution, the photovoltaic (PV) system has become one kind of important renewable energy source. This study is aimed at developing a PV charging system for Li-ion batteries by integrating Maximum Power Point Tracking (MPPT) and charging control for the battery. In order to enable the solar cell to use the sunlight effectively, a DC/DC boost converter for solar power generation was first designed, which used the MPPT Algorithm of Variable Step Size Incremental Conductance Method (VSINC) to enable the solar cell to track the MPPT at any time. The output from the DC/DC boost converter then entered the DC/DC buck converter to reduce the voltage for charging purposes. The charging system uses a constant current/constant voltage(CC/CV) method to charge the Li-ion battery. The PI controller for CC/CV charging method is designed by two intelligent algorithms included PSO and GA methods to determine the optimal values of PI controller's gains. Compare PSO method with GA method to find the optimal PI controllers, it showed that the PSO method had faster IAE convergent rate. The numerical simulations and experimental results do verify that the PI controller design by PSO method had better system responses than the GA method. Otherwise, the PV charging system proposed by this study is easily realized, and can resist the disturbance of external environmental changes for a portable solar charger module.
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