Photovoltaic Power Led Lighting Control System

Along with the energy crisis and environment deterioration, countries all over the world, including China, are seeking for possible countermeasures either by developing energy-saving technique or by utilization of green and reproducible energy.Semiconductor PN-conjunction structure used in LED lighting industry and solar photovoltaic field are environmentally friendly, energy-saving, durable and secure.Effective combination of these two techniques serves aims of energy saving, environment protection and sustainable development. Thus, concerned research work is of considerable importance.The present work investigates the control system of solar LED lighting system. Improvements are performed in both hardware and software of the system according to features of solar photovoltaic techniques and LED lighting techniques. The main works go as follows:1. Effective circuits of solar panel and lead-acid battery are researched. Based on the test result of solar panel, consideration of advantages and disadvantages of buck circuit, boost circuit and sepic circuit leads to the use of sepic DC-DC converter. This ensures that voltage output from the solar panel can fulfil maximum power in the maximum varying range of external environment as well as the SOC and internal resistance of lead-acid battery.2. Aging test lasted one year on LEDs driven by constant DC source and constant pulse source with the same effective current is performed. Experimental data prove the edge of high frequency pulse source.3. Abnormal degradation of high-power white light LED during aging test and degradation mode under the condition of overload are experimentally explored. Correlated analyses plus the theoretical explanation of LED degrading modes provide foundation for the design which drive series LED with constant pulse current.4. MPPT algorithm for solar LED lighting system is constructed, using IncCond (Incremental conductance method) as the control strategy.