M. Uzunoglu

A dynamic lithium-ion battery model considering the effects of temperature and capacity fading

Battery models capture the characteristics of real-life batteries, and can be used to predict their behavior under various operating conditions. In this paper, a dynamic model of lithium-ion battery has been developed with MATLAB/Simulink® in order to investigate the output characteristics of lithium-ion batteries. Dynamic simulations are carried out, including the observation of the changes in battery terminal output voltage under different charging/discharging, temperature and cycling conditions, and the simulation results are compared with the results obtained from several recent studies. The simulation studies are presented for manifesting that the model is effective and operational.

A dynamic ultra-Capacitor model for vehicular applications

Ultra-capacitor (UC) models capture the characteristics of real-life UCs, and can be used to predict their behavior under various operating conditions. In this paper, a dynamic model of UC that can be useful for vehicular applications has been developed using MATLAB/Simulink®. Dynamic simulations are carried out to obtain the changes in UC terminal output voltage under different charge/discharge rates and temperature conditions. Then, the simulation results are verified compared with the results obtained from experimental studies. Comparisons show that the model is effective and operational.

Financial payback analysis of small wind turbines for a smart home application in Istanbul/Turkey

Small-scale wind turbines are promising renewable energy devices driven by the aim of carbon savings at energy generation. However, the use of small-scale wind turbines in residential areas is still very narrow because of low wind speeds, high turbulence intensity, and the perception of high aerodynamic noise produced by wind turbines. Furthermore, their high cost make it essential to assess the turbines carefully before deciding to purchase so that the optimum performance and costs can be obtained. In this study, power curves of bestselling small scale wind turbines in Turkey are compared using experimentally collected one year wind data for the use in a smart home environment at Davutpasa Campus, Istanbul. The total annual energy production of the wind turbines and financial payback periods are calculated. With the results of performed analysis, it is possible to define the most profitable small wind turbine to be used in related applications in Istanbul and in areas where wind speed is similar.

A wavelet-ADALINE network based load sharing and control algorithm for a FC/UC hybrid vehicular power system

The most attractive features of fuel cell technologies are the environment friendly operation and fuel economy. Instead of using only a FC system for vehicle propulsion, hybridizing FC system with an energy storage system provides many advantages. Fuel cell (FC) and ultra-capacitor (UC) based hybrid power systems appear to be very promising for satisfying high energy and high power requirements for vehicular applications. In this study, an adaptive linear neuron (ADALINE) network and wavelet transform based energy management strategy developed for a FC/UC hybrid vehicle system is proposed. While wavelet transforms are suitable for analyzing and evaluating the dynamic load demand profile of a hybrid electric vehicle (HEV), the use of adaline network controller is appropriate for the hybrid system control. The mathematical and electrical models of the system are developed in detail and simulated using Matlab®, Simulink® and SimPowerSystems® environments.

Carbon emission savings with a renewable energy supplied smart home operation

Recently, ideas like smart cities, smart buildings/homes has been widely used under smart grid concept, which is a new research area that combines power systems and information technology (IT). The basic building block of the smart grid can be considered as “smart home”. Smart grid infrastructure with smart homes will allow to monitor electrical demand of a city or a residential customer and to achieve better utilization of existing grid through the use of streaming demand data. In addition, it will be easier to integrate renewable energy sources into existing grid. Experimental demonstrations are important for promoting smart grid concept. Thus, a renewable energy supplied smart home project with a budget of

Static Modeling of Microgrids for Load Flow and Fault Analysis

0.5 million has been completed at Yıldız Technical University (YTU), Istanbul, Turkey. This paper first introduces the constructed smart home in detail. Then, the benefit of smart home operation on carbon emission reduction with appliance control through smart plugs is analysed by a simulation study in Matlab/Simulink.

Implementation of a reliable load sharing strategy between battery and ultra-capacitor on a prototype electric vehicle

Inverter interfaced distributed generators (DGs) in microgrids have different characteristics and models that are not available in the existing conventional power flow analysis tools. This paper presents a static modeling approach for inverter interfaced DGs that can be applied for time spread load flow analysis and fault analysis of microgrids, including droop-based voltage controlled DGs. The static models have been derived from the common control schemes applied to inverter interfaced DGs, including the constraints emerging from droop control and reflect steady-state behaviors of inverters accurately. In addition to simplification of analysis procedure, the static models can provide a base for the analysis of microgrids with conventional numeric analysis tools. The presented static modeling approach has been validated comparatively with the dynamic modeling results of a test microgrid.

Smart insular grids: Opportunities and challenges

In this study, a battery and ultra-capacitor (UC) hybrid electric vehicular system is proposed. The battery supplies the long term energy requirements of the vehicle while UC is employed for picking up the transient load variations that can seriously damage the electrochemical structure of the battery. An experimental assessment of the constructed vehicle prototype of such hybrid structure is realized under a real time drive cycle. The proposed system provides the advantages of eliminating of the supervisory control system necessity as well as realizing a more reliable local control approach based on voltage regulation compared to current based control approaches.

Small scale test bench based performance analysis of a fuel cell/ultra-capacitor hybrid vehicular power system with an improved power conditioning unit

The ever increasing environmental concerns together with depletion risk of conventional fossil fuels that can threat the energy independence of energy importing countries have led to more interest in renewable energy sources of locally produced energy. Increase in such sources together with new types of integrated loads has required new concepts to operate bulk electricity power grid. Accordingly, a relatively new concept - the smart grid - has been widely publicized recently with huge investments of both developed and developing country governments in this area. The smart grid concept is currently in the test phase and insular grids have been generally considered as one of the most suitable structures to evaluate the applicability of “smart” solutions. Thus, the general structure and applicable smart grid based strategies are presented in this study to promote the overall operating performance of such systems. The opportunities as well as the possible challenges of smart solutions are discussed, and the future requirements are evaluated.

Genetic algorithm based optimal self-tuning fuzzy logic controller for power system static VAR stabiliser

For vehicular systems, fuel cells (FCs) are considered as a potential long term alternative to replace conventional combustion engines. However, high cost and slow dynamic response of FC are still the main challenges for wider applications. To overcome this problem, an auxiliary power system with adequate power capacity has to be incorporated. Ultra-capacitors (UCs) can provide an applicable solution in this aspect. Thus, a test bench of FC/UC hybrid configuration that can be suitable for vehicular systems is presented in this paper. In addition, an improved power conditioning unit (PCU) that can enhance fuel economy compared to conventional converter topologies is provided. Two different hybridization topologies are examined from different aspects. A test bench performance verification of a fuzzy logic based energy management strategy that was discussed in earlier simulation-based studies of the authors is investigated. Experimental results with small-scale devices, namely, a PEMFC (1200 W, 46 A) manufactured by the Ballard Power System Company, and four UC modules (58 F, 15 V) manufactured by the Maxwell Technologies Company, illustrate the performance analysis of both the applied PCUs and employed energy-management scheme during load cycles.