Electical Engineering

Multi-junction solar cells (MJSCs) are a current trend in the field of solar cells and form the backbone of concentrated photovoltaic systems. They are an attractive option because of their high efficiency, better power production and cost effectiveness. The aim of this paper is to present a general mathematical model of MJSC, suitable for computer simulation. This model investigates cell characterization curves including current density and power curves as a function of voltage for different concentration levels and number of junctions. The effect of varying material properties of junctions and tunneling layers is also analyzed. Two different types of MJSCs have been tested on the model, including InGaP–GaAs dual-junction solar cell with tunneling layer of InGaP and InGaP–GaAs–Ge triple-junction solar cell with tunneling layers of GaAs. Paper also presents the simulation results which are in agreement with practical conclusions.

Smart Meter is a key element in the evolving concept of Smart Grid, which plays an important role in interaction between the consumer and the supplier. In general, the smart meter is an intelligent digital energy meter that measures the consumption of electrical energy and provides other additional services as compared to the conventional energy meters. One of the important element that makes a meter smart and different is its communication module. Smart meters usually have two-way and real-time communication between the consumer and the supplier through which its transfer data and information. In this paper, Ultra Wide Band (UWB) is recommended as communication platform because of its high data-rate and presents the physical layer, which could be easily incorporated in existing Smart Meters. The physical layer is simulated in MATLAB Simulink and the results are provided.

The distributed resources – distributed generations, storage, electric vehicles and smart appliances – have fueled many disruptions in the conventional grid dynamics. Increasing tough and competitive situations at demand-side have led the stakeholders of power system to reform, because people are more informed and can make decisions that has given rise to turbulent and volatile electricity markets. In such highly diversified and open market environment, the integrated control strategy has expedited the concept of Demand Response. Currently, the important questions in the area of demand response are likely to shift from whether to adopt dynamic pricing to how to achieve fast demand response by the combination of technology and a competitive retail electricity market.This paper assembles the part and parcel in the light of existing technologies for the development of the concept of agility in demand response, that can play a role as a service package which is designed to meet the customer satisfaction efficiently and reliably as well as improve the market responsiveness.For the first time, this paper encompasses the concept of Agile Demand Response that is defined as the ability of power system to survive and prosper in the competitive retail market by reacting to the market needs fast and effectively which are driven by the customers. This paper also presents the key enablers of the agile demand response, which are (1) Retail Market, (2) Virtual Supply-demand matching mechanism, (3) Integrated information system and (4) Stay Committed. The paper concludes that by bringing the enablers together – Agile DR improves the responsiveness to the retail market changes unambiguously.

Multi-junction solar cells play an important and significant role in the Concentrated Photovoltaic (CPV) Systems. Recent developments in Concentrated Photovoltaic concerning high power production and cost effective-ness along with better efficiency are due to the advancements in multi-junction cells. Boeing SpectroLab Inc. has introduced a Multi-junction solar cell employing tunnel junctions which improves efficiency up to 40%.