Supercapacitor assisted power converter for DC microgrid applications with self-contained DC-UPS capability

摘要

Nowadays, due to the advantages inherent in using renewable energy, renewable power generation is becoming established worldwide. Direct current (DC) microgrid systems, which have been proposed as alternatives for traditional alternating current (AC) networks, enable the introduction of a large amount of solar energy by using distributed photovoltaic generation units. Meanwhile, small-scale DC microgrid systems designed at the household level are also viable options used to harness renewable energy (like solar energy) and have broad development prospects.One of the ‘hot topics’ in the field of renewable energies is how to make efficient use of this type of energy. In this thesis, a high-efficiency DC microgrid system with supercapacitor (SC)-assisted power converter is introduced as a way to harness solar energy to run a 12 V, 50 W household lighting system.Supercapacitor-assisted low dropout regulator (SCALDO) techniques were used to build an SC-assisted converter for a DC microgrid system. Supercapacitors in the DC microgrid acted as voltage droppers to convert 24 V solar panel’s output to 11 V – 13 V. Supercapacitors were also used as energy storage devices, and performed as a power source to run the household lighting system for a period of time after a sudden mains power outage.Real weather condition data, including local Hamilton illuminance values, were required to design this system. These data were measured at the University of Waikato. They were converted into irradiance data and were used to create similar patterns for simulation. Prototype circuit of the complete DC microgrid system, with an SC-assisted converter was also developed and shown at the end of the thesis.