Research On Stand-alone LED Lighting System Supplied By Photovoltaic Panel

Along with the rapid development of technology, photovoltaic (PV) energy presents great potential in distributed systems. However, as the most important element, the PV cell is still very expensive, and its efficiency of light-electricity also needs to be improved. And the PV module is conventionally connected to battery with a blockading diode in the usual solar system's configuration, which leads the actual efficiency to be lower because the operation point of the solar module is allowed to drift according to uncontrolled load and atmospheric conditions variations. In order to maximize the energy conversion, power electronics converters controlled with Maximum Power Point Tracking (MPPT) algorithms that consider the nonlinear output characteristic of PV modules should be used.In Chapter two of the paper, configuration principal and electrical characteristics of solar lighting system are introduced first. Then the author takes research into the characteristics of the solar cell, especially the influence of the equivalent series/parallel resistor on the output of the cell.Conventional perturb and observation (P&O) MPPT strategy will make the final operation point of the solar module oscillate at the MPP, thus results in the power loss of the solar energy. The thesis proposes a different implement of a P&O MPPT algorithm that can mitigate/reduce the main drawbacks commonly related to the P&O method. And the proposed strategy can also begin a new MPPT if the temperature or atmospheric conditions changes.Finally, Experimental results for a dc-dc controlled with a MCU system are presented to validate the analysis and verify the performance of the proposed control scheme.