Bidirectional smart charging of electric vehicles considering user preferences, peer to peer energy trade, and provision of grid ancillary services
INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS
Authors: Al-Obaidi, Abdullah; Khani, Hadi; Farag, Hany E. Z.; Mohamed, Moataz
Electric vehicles (EVs) are witnessing increased utilization throughout the world as an alternative to fossil-fueled vehicles. The extensive deployment of EVs can bring challenges to the grid if not properly integrated. Such challenges, however, could be exploited as opportunities if the huge unused capacity of the battery storage in millions of EVs are utilized for ancillary services to the grid and peer-to-peer (PtP) energy trade. Given that there is at least one human user per vehicle, human input must be considered to improve the scheduling process. To that end, this paper presents a new algorithm for bidirectional smart charging of EVs considering user preferences, PtP energy trade, and provision of ancillary services to the grid. The preferences of an EV user as input to the model are embedded into the scheduling process enabling the model to be adaptive to various conditions. Optimization slack variables are utilized for optimal management of EV battery SOC and energy allocation for multiple services. New indices are developed and introduced for quantification of the EV participation in ancillary services and PtP transactions. Real-world data has been collected and utilized for model specification and simulation to make the assumptions more realistic. The efficacy and feasibility of the proposed model are validated using numerical studies. The results indicate that incorporating users' preferences into the scheduling process would improve the aggregated revenue generated by the EV scheduling model which in turn could offset the charging costs by up to 100%. Further, an increase of about 90% in peer-to-peer energy transactions among EVs and 11% in ancillary services provision to the grid are achieved through the developed user-centric smart charging model.
Investigation on structural, optical and electrical properties of Nd doped titania films and application of optical model
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
Authors: Kompa, Akshayakumar; Chaitra, U.; Kekuda, Dhananjaya; Rao, Mohan K.
The effect of dopant concentration and temperature on the structural, optical and electrical properties of TiO2 (Titania) thin films deposited through sol-gel spin coating was investigated. The X-Ray Diffractometer was used for phase analysis, UV-Vis spectrometer and Ellipsometer techniques were used for the optical measurements and Hall effect was used for the electrical characterization. Annealing temperature and dopant concentration were chosen as the parameters in the present study. The optical band gap marginally increased from 3.40 eV to 3.43 eV with increase in dopant concentration for the films annealed at 350 degrees C. The increasing trend was also observed for the films annealed at 450 degrees C with the optical band gap in the range 3.34 eV-3.39 eV. Using ellipsometric measurement, thickness and optical constants were obtained and we compared the refractive index values with those obtained from PARAV software. For Nd doped films, a single oscillator model was tested by using the refractive index values from ellipsometric measurement. The carrier density and plasma frequency were calculated using the Wemple Di Domenico (W-D) model. The electrical properties indicate decreased resistivity from 103 omega cm to 101 omega cm and increased carrier density from 10(15) cm-3 to 10(17) cm(-3) with increase in annealing temperature. Similarly, with increase in dopant concentration at a given annealing temperature, we have observed a decreased resistivity compared to the prestine samples. However, the carrier density increased marginally with increase in dopant concentration.