Satish M. Mahajan

V2G Parking Lot With PV Rooftop for Capacity Enhancement of a Distribution System

Vehicle-to-grid (V2G) units are gaining prominence and may dominate the auto-market in the near future. The V2G batteries require corporate parking lots for charging and discharging operations. The electric power capacity of an existing parking lot can be increased by the installation of photovoltaic (PV) rooftops. This paper describes mathematical models for estimating the electric power capacity of a V2G parking lot (VPL) system with PV canopy. The electric vehicle (EV) demand/supply model was formulated as a queuing theory problem, exhibiting stochastic characteristics. New formulae were developed to address the impacts of battery charger efficiency on the amount of power demand during battery charging, and also how the latter is effected by inverter efficiency during discharging. Mathematical models for grid gain factor were developed. The proposed models were tested using Tesla Roadster EV and Nissan leaf EV. Promising simulation results are gained leading to a conclusion that vehicle parking lots with PV facilities can potentially relieve and enhance the grid capacity. Results show that 60% gain factor is possible. The effect of weather uncertainties and energy market price were studied. The study could be useful in battery-charger control studies.

V2G electric power capacity estimation and ancillary service market evaluation

Sharing power assets between transportation and power system is the focus of V2G that can create a compelling new economics. Projected V2G penetration levels across utility customers are a promising clue that V2G may dominate the market in the near future. This will herald evolution of V2G parking lots. This paper describes mathematical model for estimating the electric power capacity of a V2G parking lot system. The electric vehicle demand/supply model was formulated as a queuing theory problem, exhibiting stochastic characteristics. This paper addresses the modeling of V2G power demand and supply as well as evaluation of its electricity market potentials. Promising simulation results are gained leading to a claim that V2G electric power capacity can be substantial with attractive ancillary services revenue opportunities. The proposed model was tested using Tesla Roadster EV and PHEV versions. Results could be useful for power system software developers seeking base case data capacity estimation of V2G parking lots. An expression for grid gain factor was developed, and analysis showed that 40.3% optimal gain factor is obtainable.

Real-Time Management of Power Systems With V2G Facility for Smart-Grid Applications

Real-time application in power systems is a key to smart-grid realization. Maintaining accurate security information and monitoring the changing system state are necessary for real-time management of the modern-day power system. Smart-grid applications provide an excellent opportunity to better manage the voltage stability of the power system. Using intelligent electronic devices, it is possible to capture power system data, and give an instantaneous snapshot of the system status. The penetration of vehicle-to-grid (V2G) into the power system may introduce a high-level of volatility due precarious charging/discharging operations, hence emphasizing the need for a real-time management option. In this paper, a real-time monitoring diagnostic of the power system is presented. The system parameters for consideration are voltage profile, voltage stability, step voltage regulators (SVRs) operations, power, and energy loss. Economic studies are also considered. Results show that for a given V2G penetration level, three-phase and system-wide V2G integration results in an improved system performance, and economic operation of the power system than a one-phase V2G integration. Results also indicate that using V2G parking lots to inject reactive power to the grid at an optimal location can promise about 95% power/energy loss reduction (relative to power loss without V2G installed). The results are suitable for further applications of smart grids.

Electromagnetic wave technique to determine radiation torque on micromachines driven by light

A method to determine radiation torque on a dielectric microrotor driven by a focused laser beam, while considering the wave nature of the incident light, is introduced. The method involves numerically determining the electric and magnetic field quantities of the scattered light on the surface of the rotor using the finite difference time domain method. Maxwell’s stress tensor is then employed to calculate the force over the rotor surface, enabling the determination of the rotor torque about the axis of rotation. The method is demonstrated using a simple rotor shape, with results that are in good qualitative agreement with observations reported in literature.

Nanotechnology in the Development of Photovoltaic Cells

Over fifty years, numerous studies have been performed on different design aspects and performance characteristics of photovoltaic (PV) cells with a common goal of producing fully integrated PV modules to compete with the traditional energy sources. A relatively new field of nanotechnology has opened up new and promising possibilities to improve environmental quality and economic prosperity. This paper reviews the performance of traditional PV cells and outlines the recent developments in nano-tech related to solar cells. Developments in nano-tech solar cells via nanotubes, quantum dots, and hot carriers could reduce the cost of PV cells and modules for bulk power generation as well as improve the cell conversion efficiency. The current production growth and the cost of PV cells and modules are also discussed.

Design of a docking station for solar charged electric and fuel cell vehicles

An effect of constant increase in the price of hydrocarbon-based fuels and the resulting pollution of environment have motivated researchers and the automobile industry to take a serious look at electric vehicles (EV). Hybrid technologies have also found their place in the automobile industry. Hybrid Electric and Plug-in Hybrid Electric Vehicles are being developed and improved constantly. An electric vehicle plugged in a docking station that stores energy from a solar panel array is probably the best way to charge a short-distance commuter EV rather than connecting it to the grid. Production of hydrogen by electrolysis of water and subsequent use through fuel cells is another possibility of using solar energy. A docking station consisting of solar panel array, DC-to-DC converter and batteries was designed. Compatibility with hydrogen electrolyzer was considered with emphasis on efficiency. Two separate tracks for plug-in vehicle were followed: a) Electric Energy Conversion; and, b) Proton Exchange Membrane (PEM) fuel cell. Range of the vehicle, charging rate and initial cost of the two separate tracks were calculated so that a direct comparison could be presented. Short distance commuters are the primary requirements for daily transportation of most individuals. Considering an average traveled distance of 10 miles per/day at an average speed of 30miles/hour, these vehicles and docking stations could be used in most of the North American urban areas.

Functionality of bismuth sulfide quantum dots/wires-glass nanocomposite as an optical current sensor with enhanced Verdet constant

We report optical studies with magneto-optic properties of Bi2S3 quantum dot/wires-glass nanocomposite. The size of the Q-dot was observed to be in the range 3–15 nm along with 11 nm Q-wires. Optical study clearly demonstrated the size quantization effect with drastic band gap variation with size. Faraday rotation tests on the glass nanocomposites show variation in Verdet constant with Q-dot size. Bi2S3 Q-dot/wires glass nanocomposite demonstrated 190 times enhanced Verdet constant compared to the host glass. Prima facie observations exemplify the significant enhancement in Verdet constant of Q-dot glass nanocomposites and will have potential application in magneto-optical devices.

Novel and stable Mn2+@Bi2S3 quantum dots–glass system with giant magneto optical Faraday rotations

Novel, highly stable Bi2S3 and Bi2−xMnxS3 quantum dots (QDs)–glass optical nanosystems were architectured successfully. These advanced nanosystems were characterized by High Resolution Transmission Electron Microscopy (HRTEM), UV-Vis-NIR spectroscopy and room temperature photoluminescence (PL) measurements. HRTEM of the Bi2S3 QD–glass nanosystem revealed the size of Bi2S3 QDs to be in the range of 5–7 nm. However, for the Bi2−xMnxS3 quantum dots (QDs)–glass nanosystem, the size of Bi2−xMnxS3 QDs were around 3–5 nm. The Bi2S3 quantum dots exhibit an orthorhombic structure with good crystallinity. Bi2−xMnxS3 QDs also exhibit the same structure with lower ‘d’ values due to Mn2+ incorporation. The optical study clearly reveals the growth of Bi2S3 and Bi2−xMnxS3 QDs in the glass matrix. Interestingly, a blue shift of the transmission edge was observed by incorporation of Mn2+ under the same thermodynamic conditions. Photoluminescence spectra show distinct Bi2S3 and Mn2+ related emissions, which are excited via the Bi2S3 host lattice. The Mn2+ emission intensity at 580 nm wavelength confirms the existence of Mn2+ in the Bi2S3 lattice in the glass matrix. The magneto optical Faraday rotation measurements were performed at room temperature with magnetic fields up to 5.6 mT for all the samples. Significantly, we observed a giant heightening in the Verdet constant i.e. from 159.34 to 507.30 deg T−1 cm−1 after incorporation of Mn2+ (0 to 0.4 moles), which is much higher than conventional single crystal systems like TGG, BFG (76.82 deg T−1 cm−1) as well as other materials reported so far. Our strategy provides a versatile route to controlled magneto optical properties of anisotropic semiconductor nanomaterials, which may create new opportunities for photonic devices, magnetic and current sensor applications.

PV - wind - fuel cell - electrolyzer micro-grid modeling and control in Real Time Digital Simulator

Micro-grid consisting of Photovoltaic (PV) arrays, Wind Turbine Generator (WTG), Fuel Cell, Supercapacitor and Electrolyzer (EL) serving a village load is modeled and implemented in Real Time Digital Simulator (RTDS). Operating scenarios under fluctuating load conditions using an appropriate control strategy are simulated and analyzed. The advantages of using RTDS for micro-grid studies are presented.

A Real-Time Conductor Sag Measurement System Using a Differential GPS

A real-time and “direct” method of measuring the absolute value of sag on a transmission-line conductor using a differential global positioning system (DGPS) is presented. The method includes a real-time data-processing module integrated into the DGPS system. The GPS signals corresponding to physical movement of the midspan of a transmission-line conductor were obtained so that conductor-to-ground clearance could be recorded in real time. Several field tests were designed and implemented to test the DGPS method under varying conditions of the transmission-line current. A comparison of results obtained from the DGPS method with those from a laser-range finder indicates an accuracy of 1 in.