Zekiye Erdem

Bio: Zekiye Erdem is an academic researcher from Sakarya University. The author has contributed to research in topics: Digital control & Gallium nitride. The author has an hindex of 5, co-authored 14 publications receiving 89 citations. Previous affiliations of Zekiye Erdem include University of Ontario Institute of Technology.

Wide Bandgap Devices in Electric Vehicle Converters: A Performance Survey

Abstract: This paper introduces a unique quantified study about using low-losses fast-switching wide bandgap (WBG) devices, i.e., gallium nitride (GaN) and silicon carbide (SiC), over traditional Silicon (Si) devices in the switching of dc/dc converters, focusing on electric vehicles’ (EVs) machine drive and battery charger. A detailed model of the power train of a Nissan Leaf was developed in PSIM software, with WBG semiconductors’ capability. The model was simulated one time using GaN semiconductors and another time using SiC devices. Simulation results are quantified and a comparison between different semiconductors in terms of total losses and efficiency is presented. The developed PSIM model can also be extended to other EVs like Chevy Volt. A proof of concept prototype for a Nissan Leaf dc/dc converter was built in the laboratory and results were collected. Componentwise experimental results are presented and their correlation with simulation findings is demonstrated. In addition, experimental results of the overall power train test bench are found to be matched with the simulation results on a system level as well.

Double-loop PI controller design of the DC-DC boost converter with a proposed approach for calculation of the controller parameters:

Abstract: Parameters of digital proportional–integral/proportional–integral–derivative controllers are usually calculated using commonly known conventional methods or solution of discrete-time equations. In ...

A New Approach for Calculation of PID Parameters with Model Based Compact Form Formulations

Abstract: PID controller is a popular control method still widely used in process industry. In literature there are model/non-model based calculation methods for PID parameters. However, a model based analytic formulation in compact form in discrete time has not been come across yet. This study presents a new approach for calculation of PID parameters with model based analytic formulation (MBCF), which is presented uniquely in this paper, in compact form, in discrete time. Furthermore, a procedure for implementation of the proposed formulas is given in four stages. The formulations in related literature for PID parameter calculation are all derived for continuous time. Therefore, extra transformations are required for a discrete time design. The proposed MBCF formulation method reduces extra calculation burden and simplifies calculation complexity. Moreover, this method provides a direct calculation method for digital PID controller design in discrete time. The derived expressions in this study also provide a fast, easy-implemented, and practical PID parameter calculation method for all field researchers and application engineers. The validation of proposed MBCF formulations are comparatively proved with the simulations and the real time application results. DOI: http://dx.doi.org/10.5755/j01.eee.20.3.4415

Multiagent systems: a modern approach to distributed artificial intelligence

Abstract: Multiagent Systems is the title of a collection of papers dedicated to surveying specific themes of Multiagent Systems (MAS) and Distributed Artificial Intelligence (DAI). All of them authored by leading researchers of this dynamic multidisciplinary field.

Book review: Experimental techniques in plant disease epidemiology, J. Kranz & J. Rotem (eds.). Springer-Verlag Berlin, 1989, 299 pp.

Abstract: Various textbooks have been written on the epidemiology of plant diseases. Most of them present theory of epidemiology, thus giving a description of epidemiological principles. Some of these are of a general nature, whereas others concentrate on specialized subjects, but there are no books on experimental techniques in epidemiology. This omission has been recognized and rectified by Kranz and Rotem. As mentioned in their preface they intended, by editing and publishing the book, 'to help in the development of a methodology able to provide a choice of adequate methods widely acceptable amongst epidemiologists for varying applications and objectives'. For this purpose, they invited 27 distinguished plant pathologists, a number of them from Kranz's 'stable', to participate, and to provide information from their own rich experience. There are 20 chapters spread over four sections. Section I (General techniques), deals with techniques and approaches used in experiments in the field and under controlled conditions. Advantages and disadvantages of such experiments and the relations between them are explained. In Section II (.Measurements and their analysis) disease assessment, crop development and estimation of spore production, dispersal, survival and infectiousness are treated. The analysis of spatial patterns of soil-borne pathogens {s discussed in a separate chapter, for soil-borne diseases have to be approached differently. This section is concluded with two chapters on the monitoring and analysis of environmental factors. Section III (Special topics) is a collection of items, such as the analysis of the effects of control measures, fungicide resistance, virulence in pathogen populations, components in yield loss, development of forecasters, aphid-borne epidemiology, quantitative nematology, geophytopathology and long-distance dispersal. As the editors explain, these are 'not necessarily connected with each other, but all dealing with definite objectives in epidemiological experimentation'. The reasoning for the addition of these topics to the contents is clear. Most are worth treatment, and each has specialized techniques and approaches. The reasoning for collecting them all together under 'Special topics' is a little unsatisfactory. A rather simple rearrangement and naming of the subjects could separate them into a couple of better defined chapters, which would have made the contents more accessible to the eager user. Section IV (The synopsis of experimental restilts) gives the reader a look into the methods in comparative epidemiology, and into the development and use of simulation models for root and foliar diseases. The limitations, necessarily imposed upon the authors, to prevent the publication of an unwieldy and ever more expensive handbook lead to the question whether the editors 'bit more than they could chew'. Especially the chapters on modeling and simulation suffer under these limitations. Most authors have achieved a fine work, though readers, familiar with the authors' publications, can 'taste' a bit of subject.ivity in the choice and approach of techniques and methods by some of them. The book might be a useful addition to the library of all those involved in experimental work in epidemiology, but particularly those called 'novices in epidemiology' in the preface. The editors may have had undergraduates and young postgraduates in mind, but this work might be useful for other epidemiologists too. It is a pity that the high price will hinder young scientists from purchasing the book, particularly those in developing countries.

Power module electronics in HEV/EV applications: New trends in wide-bandgap semiconductor technologies and design aspects

Abstract: A large number of factors such as the increasingly stringent pollutant emission policies, fossil fuel scarcity and their price volatility have increased the interest towards the partial or total electrification of current vehicular technologies. These transition of the vehicle fleet into electric is being carried out progressively. In the last decades, several technological milestones have been achieved, which range from the development of basic components to the current integrated electric drives made of silicon (Si) based power modules. In this context, the automotive industry and political and social agents are forcing the current technology of electric drives to its limits. For example, the U.S Department of Energy’s goals for 2020 include the development of power converter technologies with power densities higher than 14.1 kW/kg and efficiencies greater than 98%. Additionally, target price of power converters has been set below $3.3/kW. Thus, these goals could be only achieved by using advanced semiconductor technologies. Wide-bandgap (WBG) semiconductors, and, most notably, silicon carbide (SiC) based power electronic devices, have been proposed as the most promising alternative to Si devices due to their superior material properties. As the power module is one of the most significant component of the traction power converter, this work focuses on an in-deep review of the state of the art concerning such element, identifying the electrical requirements for the modules and the power conversion topologies that will best suit future drives. Additionally, current WBG technology is reviewed and, after a market analysis, the most suitable power semiconductor devices are highlighted. Finally, this work focuses on practical design aspects of the module, such as the layout of the module and optimum WBG based die parallelization, placement and Direct Bonded Copper (DBC) routing.

Next generation electric drives for HEV/EV propulsion systems: Technology, trends and challenges

Abstract: In recent decades, several factors such as environmental protection, fossil fuel scarcity, climate change and pollution have driven the research and development of a more clean and sustainable transport. In this context, several agencies and associations, such as the European Union H2020, the United States Council for Automotive Research (USCAR) and the United Nations Economic and Social Commission for Asia (UN ESCAP) have defined a set of quantitative and qualitative goals in terms of efficiency, reliability, power losses, power density and economical costs to be met by next generation hybrid and full electric vehicle (HEV/EV) drive systems. As a consequence, the automotive electric drives (which consists of the electric machine, power converter and their cooling systems) of future vehicles have to overcome a number of technological challenges in order to comply with the aforementioned technical objectives. In this context, this paper presents, for each component of the electric drive, a comprehensive review of the state of the art, current technologies, future trends and enabling technologies that will make possible next generation HEV/EVs.

Current Status and Future Trends of GaN HEMTs in Electrified Transportation

Abstract: Gallium Nitride High Electron Mobility Transistors (GaN HEMTs) enable higher efficiency, higher power density, and smaller passive components resulting in lighter, smaller and more efficient electrical systems as opposed to conventional Silicon (Si) based devices. This paper investigates the detailed benefits of using GaN devices in transportation electrification applications. The material properties of GaN including the applications of GaN HEMTs at different switch ratings are presented. The challenges currently facing the transportation industry are introduced and possible solutions are presented. A detailed review of the use of GaN in the Electric Vehicle (EV) powertrain is discussed. The implementation of GaN devices in aircraft, ships, rail vehicles and heavy-duty vehicles is briefly covered. Future trends of GaN devices in terms of cost, voltage level, gate driver design, thermal management and packaging are investigated.