Power Quality Affected by DC and AC LED Bulb Loading of a PV Generator Connected to a Microgrid

Ahstract-Light-Emitting Diode (LED) bulbs or lamps are popularly used nowadays because of their less power consumption and long lifespan. However, usages of LED bulbs including the DC and AC types affect power quality of the power system because the needs of DC-to-DC converters and/or inverters. This paper presents a comparison of power quality affected by the DC and AC LED bulb loads supplied by a PV generator (PVG) connected to a PV microgrid. Various loading conditions based on centralized and decentralized drivers are carried out. Also the effect switching frequency for DC-to-DC converter used inside LED drivers is explored. The power quality is measured by means of total distortion percentage in the power line currents on both DC and AC side. The study is based on simulations using the existing simulation models of a PV generator, a converter, an inverter, DC LED bulb, and AC LED bulbs. The results show that DC LED lamp loading has higher effects to the total distortion than AC LED has. Moreover, using the centralized driver has a small advantage over the decentralized case while the distortion increases when the switching frequency is reduced. Although the resulting distortions from the simulations may not be accurate, the comparison results may be used as a guideline for designing a PV microzrid.