Field data collection for implementation of Supercapacitor Assisted LED Lighting (SCALED)

Abstract

With the increasing impact of global warming, climate change is becoming the biggest threat for all life on our planet. The conventional way of generating electricity from the burning of fossil fuels releases significant amounts of carbon dioxide to the atmosphere, which contributes to the rise in the earth’s temperature. Moreover, fossil fuels are being consumed very rapidly and we now have limited resources, which need to be monitored to face future energy demands. The development of renewable energy sources, such as solar power, is a rapidly growing technology. With the extensive research and investment in this industry at present, in the near future solar power will be one of our leading renewable energy sources. Furthermore, as solar panels directly produce direct current (DC), they can be directly tied to a DC microgrid without requiring any power converter, thereby minimizing losses and increasing efficiency. The supercapacitor assisted light emitting diode (SCALED) converter is one of the new circuit techniques under development for low voltage light emitting diode (LED) systems at the University of Waikato. In this circuit, an LED is connected in series with the supercapacitor bank forming part of a resistor-capacitor (RC) charging loop. This is to avoid energy losses in the RC charging loop, which can create, in the worst case, a 50% loss. As the commonly used 12 V LEDs are internally DC operated devices, SCALED will be applicable in DC microgrids, which are the emerging technology in low voltage distribution systems. The groundwork for this project requires various solar-related field data collection and simulations for the successful implementation of this innovative technique. Unlike a conventional power supply, solar power output directly depends on the solar irradiance level, which is very unpredictable. Given the unique behaviour of solar panel output, starting with a near constant current behaviour and changing over to a practical voltage source with an approximately constant array resistance, combining a supercapacitor bank and an LED lamp will be a challenge in developing the SCALED topology. In addition, proper field measurements and analysis of these characteristics are essential to develop more efficient and reliable SCALED circuits for DC microgrid applications.