Investigating Inverter Efficiency at Low Power for LED Lighting

Abstract

With the industrialization of society, concerns about the environment have led to the development of renewable energy approaches. Efforts are underway to provide renewable energy in remote villages, including the use of photovoltaic energy. An issue with a battery based photovoltaic energy system for a village residence is the efficiency of the DC to AC power inverter. A sub issue, not well addressed in the literature, is inverter efficiency at low power, such as the operation of a single LED light at night. It is proposed in the literature that efficiency can be increased with the use of a very low switching frequency of the inverter power transistors. A 200W MOSFET Full Bridge inverter is modelled and characterised for operation down to 3.5 W with a switching frequency of 200Hz. Using a SimuLink simulation, it is found that inverter efficiency can be increased from 59% to 77% employing this approach.