Characteristics and effects of conducted emission from grid-connected and stand-alone micro-inverters in a nano-grid road lighting system

Abstract

A road lighting system is important for drivers and uses a lot of energy. The road lighting system must be installed throughout roads which have a long distance and a large volume, which causes power loss in the power transmission line. The concept of combining a power generation system by using a solar power system and a road lighting system is presented to solve this problem; it is called "a nano-grid road lighting system". The nano-grid system consists of a grid-connected system and a stand-alone system and both systems use micro-inverters to convert the electric power for LED luminaire loads. Both micro-inverters are comprised of switching devices that cause the conducted emission (CE) in the electrical system. The LED luminaire is a very sensitive load because it is less resistant to the CE. Therefore, this research studies the CE in the nano-grid system in each period according to the working pattern of the device to study the CE characteristics for use in the design of CE attenuation methods in the future. The CE of the stand-alone system which is used at nighttime gives a higher level than the grid-connected system and exceeds the Comité International Spécial des Perturbations Radioélectriques (CISPR) 14-1 standard. The CE of the grid-connected system has a high level in the early frequency ranges, whereas the CE of the stand-alone system has a high level throughout the test frequency range.