Investigation and Comparison of DC and AC NanoGrids /

Abstract

The depletion of fossil fuels and their damaging effects on the environment has shifted the focus towards renewable energy sources to meet the increasing global energy demand. To effectively use renewable sources of energy they should be used in combination with other sources. Therefore, their use is preferred in distributed generation. For efficient utilization of distributed generation, NanoGrid (NG) are formed. NG are typically small electrical networks consisting of a small building or a house. These NG can be AC or DC. Since presently the use of DC devices (Laptops, LED’s, cell phones etc.) and DC generation sources like Photovoltaics (PV) and the wind have increased, the emphasis is shifting towards DC NG. There is a lot of debate among researchers as to which NG network is more energy efficient but a detailed analysis has not been carried out to determine which system is better. Therefore, in this study, a detailed simulation analysis is carried out on both DC and AC NG using various case studies to determine which is better in terms of energy efficiency. An architecture for both DC and AC NG is modeled in MATLAB Simulink consisting of a grid-tied inverter, PV system, an EV and several domestic loads (LED light, LED TV, Laptop, Air Conditioner, Fan, Refrigerator). Three case studies are made to carry out a detailed loss analysis on both networks. The simulation results show that the DC NG is better than an AC NG in terms of energy efficiency. An economic analysis is also done on DC and AC devices to check which system is better in terms of cost. The results of this study can also be used for modeling of future NG systems.