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EPE-PEMC 2006 - Topic 16: SPECIAL SESSIONS
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	A Comprehensive Overview on Reactive Power Compensation Technologies for Wind Power Applications   By Ahmed Faheem Zobaa, Milutin Jovanovic	[View]   [Download]
Abstract: The size and number of wind farms contributing to the energy production is continuously growing. The rating of wind turbines has increased from less than 1 MW a few years ago to 2- to 3-MW being installed today with 5- MW machines under development. The interaction of the wind farm, reactive power compensators, and the associated power network is being investigated. Because the loads and the wind farms' output fluctuate during the day, the use of reactive power compensation is ideal for the power system network. The purpose of this study is to provide wind farm developers and interested researchers with some valuable insights into the reactive power compensation techniques for wind farm power systems.
	A Single-Phase Shunt Active Power Filter for Current Harmonic Compensation by Adaptive Neural Filtering   By Maurizio Cirrincione, Marcello Pucci, Gianpaolo Vitale, Giuseppe Scordato	[View]   [Download]
Abstract: This paper presents a single-phase shunt active power filter for current harmonic compensation based on neural filtering. The shunt active filter, realized by a current controlled inverter, has been used to compensate a nonlinear current load by receiving its reference from a neural adaptive notch filter. This is a recursive notch filter for the fundamental grid frequency (50 Hz) and is based on the use of a linear adaptive neuron (ADALINE). In this way the inverter creates a current equal in amplitude and opposite in sign to the load harmonic current, thus creating an almost sinusoidal grid current. The methodology has been applied in numerical simulations and experimentally on a properly devised test setup. With this regard, a reduced scale electrical grid has been built and used for assessing this methodology.
	Adaptive Neuro-Fuzzy Control of the Sensorless Induction Motor Dive System   By Teresa Orlowska-Kowalska, Mateusz Dybkowski, Krzysztof Szabat	[View]   [Download]
Abstract: In the paper a model reference adaptive control speed control (MRAC) using on-line trained fuzzy neural network (FNN) was applied to the sensorless induction motor drive system. In this control method fuzzylogic controller is equipped with additional option for online tuning its chosen parameters. In the paper PI-type fuzzy logic controller is used as the speed controller, in the field oriented control structure, whose connective weights are trained on-line according to the error between the states of the plant and the reference model. The FNN speed controller is on-line tuned to preserve favorable model-following characteristics under various operating conditions. The rotor flux and speed of vector controlled induction motor was estimated using the full-order state observer and speed estimator. The simulation results were verified in the experimental tests, in the wide range of motor speed and parameters changes.
	Analysis of Cross-Saturation Effects in a Linear Synchronous Reluctance Motor Performed by Finite Elements Method and Measurements   By Gorazd Stumberger, Bojan Stumberger, Drago Dolinar	[View]   [Download]
Abstract: This work deals with cross–saturation effects in a linear synchronous reluctance motor (LSRM). A general magnetically nonlinear two–axis dynamic model of LSRM is introduced. It accounts for the effects of slotting, saturation, cross–saturation, anisotropy and the end effects. Parameters of this model are not constant. They are position and current dependent. This work focuses on analysis of cross–saturation effects. Therefore, the model parameters representing cross– saturation effects are identified. Their characteristics are determined by the finite element calculations and by experimental methods. The results obtained in this way are used to evaluate the effects of cross–saturation.
	Bifurcation Behavior of a Three Cell DC-DC Buck Converter   By Abdelali El Aroudi, Bruno Robert, Luis Martínez-Salamero	[View]   [Download]
Abstract: Most of nonlinear analysis techniques used for studying the stability of power electronics systems has been applied to particular cases such as the buck converter under voltage mode control, boost converter with current programmed control, etc. This is due to the inherent complexity of the mathematical description of such systems in spite of their topological simplicity. In this paper, we extend the use of these techniques for studying stability of periodic orbits of a three cell DC-DC buck converter. We begin by giving the state space description of the system dynamical behavior of the system. Then, a discrete time model in the form of a Poincaré map is described and used for stability analysis. The expressions of the fixed point and the Jacobian matrix of this map are given in closed form in terms of system matrices. Instabilities in the form of generic bifurcations like period doubling and Neimark-Sacker bifurcation can be be detected accurately. Numerical simulations confirms the theoretical predictions.
	Comprehensive Experimental Analysis of the IPMSM for Automotive Applications   By Dorin Iles-Klumpner, Ioan Serban, Milorad Risticevic, Ion Boldea	[View]   [Download]
Abstract: The present paper deals with the in-depth experimental analysis of PMSM considering the motor design solution for an electric assisted active steering system as a case study. The experimental motor and the complete laboratory set-up including the power electronic, motor control and measurement devices are presented. A comprehensive measurement procedure will be described and the measurements results will be presented and interpreted.
	Control and Stabilization of DC/DC Buck-Boost Converters Loaded by Constant Power Loads in Vehicular Systems using a Novel Digital Scheme   By Alireza Khaligh, Sheldon S. Williamson, Ali Emadi	[View]   [Download]
Abstract: Power electronics based power systems are being increasingly considered for transportation systems such as land, sea/undersea, air, and space vehicles due to their advantages in efficiency, performance, flexibility, and power density. In order to have superior performance, these multiconverter systems need to be rigorously regulated. Dynamic response of tightly regulated power electronic converters in distributed power electronic systems is similar to the dynamic response of a constant power load (CPL), which acts as negative impedance and destabilizes the DC bus and the system. In order to mitigate the instability problem in multi-converter systems, in this paper, we present a novel digital technique to control DC/DC converters driving CPLs in vehicular systems. The proposed method achieves the output voltage regulation based on generating high and low power pulses instead of conventional pulse width modulation (PWM) techniques. It is simple, straight forward, and easy to implement in specifically designed integrated circuits (IC), digital signal processors (DSP), or field programmable gate arrays (FPGA). Moreover, its dynamic response is fast and robust. Simulation results of applying the proposed method to a DC/DC buck-boost converter confirm the analytical results.
	Coupled FEM-Control Simulation in the Analysis of Electrical Machines and Converters   By Sami Kanerva, Jukka Kaukonen, Aron Szucs, Terttu Hautamaki	[View]   [Download]
Abstract: Coupled simulation environment is presented, where electrical machines are modeled by the finite element method (FEM) with circuit equations and coupled to converter models in a system simulator. The method is based on weak coupling, providing possibility for multiple time step levels in the system model. Examples concerning the analysis of current and voltage harmonics, additional losses and tooth forces, are presented for 2 MW cage induction motor, 9 MW and 12.5 MW synchronous motors and 1.5 MW permanent magnet synchronous motor supplied by frequency converters. Also the future outlook of coupled FEM-system simulation is discussed in terms of the actual need for coupled models and the research interests on the coupling method development.
	DC Power Gyrator Versus DC Power Transformer for Impedance Matching of a PV Array   By Angel Cid-Pastor, Luis Martinez-Salamero, Corinne Alonso, Guy Schweitz, Ramon Leyva	[View]   [Download]
Abstract: A comparative analysis between a DC power transformer and a DC power gyrator on equal bases of operation is presented. Both approaches are used to solve the problem of maximum power transference from a PV panel to a DC load. An outdoor measurements system has been implemented and comparative experiments have been carried out during six hours. Results show that both approaches are practically equivalent in terms of efficiency.
	Design Aspects for Power MOSFET Components in Automotive Electronics   By Andreas Lindemann, Stefan Foerster	[View]   [Download]
Abstract: This paper gives a review of some approaches to include power electronics into vehicle electrical distribution systems. The focus is on converters with low voltage — typically 12V — DC link and a power rating leading to currents of several 10A to several 100A. Exemplary state of the art technologies of MOSFET devices and peripheral electrical, thermal and mechanical design are outlined including their major limitations. Those might be extended or overcome applying appropriate design methods, designs and materials which have been proposed recently. Several of those are discussed, referring to the semiconductor chips, their packaging in components and some aspects of system integration.
	Eddy Current Computation in 3-Dimensional Models for Electrical Machine Applications   By Andrzej Demenko	[View]   [Download]
Abstract: The paper presents the finite element method applied to eddy current problems in electrical machines and actuators. Both scalar and vector potential formulations are analysed. The nodal element and edge element methods are considered. The finite element equations are expressed using the notion of equivalent magnetic and electric networks coupled via sources. The presented network models contain branches associated with element edges (edge networks) or facets (facet networks). The network model of squirrel-cage winding and multiturn windings composed of solid conductors have been discussed.
	Effects of Voltage Dips on Doubly Fed Induction Generators and its Power Electronic Components   By David Santos-Martin, Santiago Arnalte, Jose L. Rodriguez-Amenedo, Jose M. Tena	[View]   [Download]
Abstract: This paper presents the influence of the voltage dips on the variable speed wind turbines with Doubly Fed Induction Generators (DFIG) and its power electronic components. A typical medium size turbine is modelled including the ac/dc/ac converters within Matlab/Simulink/ Simpower SystemsTM. Suitable speed, torque and reactive power controllers are implemented choosing classical VFO control. These studies are used to define the influence of the voltage perturbation on each electrical or mechanical variable, included the IGBT’s currents.
	Efficiency Considerations and Measurements of a Hybrid Energy Storage System based on Compressed Air and Super Capacitors   By Alfred Rufer, Sylvain Lemofouet	[View]   [Download]
Abstract: This paper presents a study and experimentation of a hybrid energy storage system prototype, based on Compressed Air, where the charging and discharging is done within maximum efficiency conditions of the volumetric machine. As the maximum efficiency conditions impose the level of the converted power, an intermittent time-modulated operation mode is applied to the thermodynamic converter to obtain a variable converted power. A smoothly variable output power is achieved with the help of a supercapacitive auxiliary storage device used as a filter. The paper describes the concept of the system, and reports on the calculated energetic efficiency performance, as well as measured on a first prototype system.
	Electrical Torque Boosting of Down-Sized ICE Vehicles   By Ben Taylor, Zhigang Sun, Jiabin Wang, David Howe	[View]   [Download]
Abstract: An effective approach for improving fuel economy and reducing emissions is to employ a down-sized, turbocharged internal combustion engine (ICE). However, turbocharged engines exhibit a relatively low torque capability at low engine speeds. To overcome this problem, an electrical torque boost may be applied whilst accelerating and changing gear, and to facilitate energy recovery during regenerative braking. The paper describes the operational requirements of such a torque boost system, which employs a supercapacitor energy storage buffer, outlines the design and sizing of the electrical machine, and presents test results from a demonstrator system.
	Encoderless Control of Industrial Servo Drives   By Oscar Cabral Ferreira, Ralph Kennel	[View]   [Download]
Abstract: High resolution optical encoders are used in industrial servo drives with position and/or speed control for providing the respective feedback signals. In applications with lower accuracy requirements resolvers are used as feedback sensors with respect to lower cost. As a resolver is nothing else than an electrical AC machine of special design, there is the basic idea to operate the servo motor itself like a resolver –in parallel to its original drive operation, of course. High frequency resolver signals are injected to the servo motor without disturbing its original purpose (i. e. the production of torque). The reaction of the servo motor on the high frequency signals can be detected by the current sensors, which are available with respect to the current control loop anyway. A lot of schemes and concepts for encoderless AC drive control providing good operation during standstill are already published. Acceptance by industry, however, is not very extended. The main reasons for hesitations in industry are: • additional processing performance being necessary for the controller or signal processor • additional sensors or hardware • parameters to be adjusted for encoderless control The concept for encoderless control presented in this paper has no restrictions with respect to a minimal speed or frequency. Furthermore it is possible to implement it in industrial servo drives without additional hardware requirements and without parameter adjustments.
	Field Simulation as an Aid to Machine Design: the State of the Art   By Jan K. Sykulski	[View]   [Download]
Abstract: The paper provides an overview of the modern field simulation techniques available to assist in the design and performance prediction of electromechanical devices, including electric motors. Commercial software, usually based on finite element or related techniques, is already very advanced and provides a reliable tool for every-day use in the design office. At the same time Computational Electromagnetics is a thriving area of research with emerging new techniques and methods, in particular for multi-physics and optimisation problems.
	Fux Deviation Sensorless Control of IPM Synchronous Motors   By Alfio Consoli, Giuseppe Scarcella, Giacomo Scelba, Antonio Testa, Domenico Triolo	[View]   [Download]
Abstract: The paper presents a position sensorless vector control able to drive Interior Permanent Magnet Synchronous Motors in any operating conditions, including low and zero speed. According to the proposed approach a constant frequency sinusoidal signal (voltage or current) is injected in the machine along a given direction so that, thanks to the rotor saliency, a periodic stator signal component is generated along a direction orthogonal to that of the injected signal. The amplitude of such an orthogonal signal depends on the phase displacement between the rotor d axis and the direction along which the additional signal is injected. A robust rotor position tracking is obtained by adjusting the direction of the additional signal in order to minimize the amplitude of the generated orthogonal response. Experimental results confirm the validity and good performance of the proposed sensorless technique.
	High-Efficiency Transformerless Single-Phase Photovoltaic Inverter   By Roberto Gonzalez, Jesus Lopez, Pablo Sanchis, Eugenio Gubia, Alfredo Ursua, Luis Marroyo	[View]   [Download]
Abstract: Grid-connected photovoltaic (PV) systems usually include a line transformer in their power conversion stage. This transformer guarantees galvanic isolation between the grid and the PV system, thus providing personal protection and avoiding leakage currents between the PV system and the ground. Furthermore, it also ensures that no continuous current is injected into the grid. However, because of its low frequency (50 Hz), the transformer is big, heavy and expensive. As an alternative to the grid-connected PV systems with line transformer, new transformerless inverter topologies are being studied. If no transformer is used, a galvanic connection between the grid and the PV array exists. In these conditions, leakage currents due to the capacitance between the photovoltaic array and earth could occur and increase the electromagnetic emissions. To avoid these leakage currents, it is necessary to use inverter topologies that avoid commonmode voltages. In this paper, a new transformerless singlephase PV inverter with six IGBTs and one diode is proposed. This topology generates no common-mode voltage and has a higher efficiency than the existing topologies. The topology has been validated by simulation.
	Modern Automotive Power Systems: Advancements into the Future   By Ali Emadi, Sheldon S. Williamson	[View]   [Download]
Abstract: The recent trend in the automotive industry is to create a new fleet of advanced vehicular technologies. The most popularly targeted automotive technology is the hybrid electric vehicle (HEV) powered by the existing internal combustion engine (ICE) technology as well as a suitable electric traction motor system. In addition, the auto industry has shown an increased interest in fuel cell vehicles (FCV) as well as battery electric vehicles (BEV), which probably might become the solutions to the inevitable oil shortage scenario that will face the world in about 50 years’ time. This paper aims at providing a detailed technological overview of proposed HEV, FCV, and BEV automotive technologies. Furthermore, this paper will present a brief comparative analysis of the above-mentioned advanced vehicular systems from the point of view of the overall cost, fuel economy, and well-to-wheels (WTW) efficiency. A brief summary of commercially available HEVs and developed FCV prototypes will be presented as well.
	MOSFET Technology as a Key for High Power Density Converters   By Lutz Goergens, Ralf Siemieniec, Juan Migel Martinez Sanchez	[View]   [Download]
Abstract: The rapidly increasing computation-capability, data-density and functionality of electronic systems are the driving forces for high-efficiency high power-density converters. Electronic systems are continuously increasing the demand for power, while simultaneously available space and cooling capability stays constant. This requires smaller form factors of the individual converter, higher efficiencies and higher output powers. To meet these demands, new power architectures, new converter-topologies and new MOSFET technologies are developed. In this paper we will review the basic operational modes for low-voltage semiconductors and mirror the resulting requirements with the capabilities of recent MOSFET technology developments.
	Multilevel AC Current Source with Sliding-Mode Control for Renewable Energy Grid Systems   By Hugo Valderrama-Blavi, Javier Maixe-Altes, Josep Maria Bosque-Moncusí, Luis Martinez-Salamero, Mauricio Munoz	[View]   [Download]
Abstract: Multilevel Conversion systems have certain advantages that can be applied in renewable energy systems. To verify that advantages we are developing a re-configurable 1 kW prototype. Among the experiments that we have considered, a sliding mode control law can force this converter to behave like an AC Current Source. We model our converter like a set of Tibuck converters operating sequentially. Some experimental results are given.
	Numerical Analysis of Radial Active Magnetic Bearings   By Bostjan Polajzer, Gorazd Stumberger, Drago Dolinar	[View]   [Download]
Abstract: The dynamic behavior of the discussed radial active magnetic bearings is analyzed using a finite element-based parametrization coupling model. Numerical calculations of the open-loop controlled and the closed-loop controlled system are performed. The results presented show that the magnetic nonlinearities and cross-coupling effects deteriorate the overall system performances.
	On the Benefit of Synchronous Rectification to Boost up the Efficiency in Mobile Adapters   By Gerald Deboy	[View]   [Download]
Abstract: Mobile AC/DC power supplies as being used e.g. for notebooks face challenging conditions: they should be compact, lightweight, not get too hot without any forced cooling, shock proof etc. Due to global usage wide input voltage range is a must. With increasing power demand of the processor and additional features of the notebook, output power increases, thermal management becomes hence an increasingly difficult task. The article analyses the losses of its active components and proposes solutions for the optimization of the system. Due to large output currents secondary side rectification with active switches is mandatory. This task is facilitated by half bridge topologies, which eliminate the need for a control IC for the secondary side rectification. A further reduction of losses can be achieved if power factor correction and main stage use resonant power architectures.
	Power Coefficient Estimation in a Wind Conversion System   By Krishna Busawon, Milutin Jovanovic, Lee Dodson	[View]   [Download]
Abstract: In this paper, we present the design of an observer/estimator for the estimation of the power coefficient in a wind energy conversion system (WECS) based on a separatly excited dc generator. It is shown that the estimator is capable of supplying accurate estimates of the power coefficient, and that it can handle measurement noise and provide satisfactory convergence qualities. A further advantage of the observer design presented is that it can be easily extended to other WECS where different types of generators are employed.
	Pseudo Sensorless Control of PMSM   By Evgen Urlep, Janko Horvat, Karel Jezernik	[View]   [Download]
Abstract: Pseudo sensorless permanent magnet synchronous motor torque and flux tracking control algorithm is presented. Proposed approach addresses the problem of operation at zero, low and up to nominal speed. The information of flux is extracted using a nonlinear closed loop rotor flux observer combined with the information obtained from hall sensors, which allows operation at zero speed. The analysis of the proposed method is included. Such control scheme was implemented on a DSP system and verified trough simulations and experiments.
	Relevance of P-Channel MOSFETs in Current and Future Applications   By Aranzazu Diaz-Valdivieso, Dirk Ahlers, Gerald Deboy	[View]   [Download]
Abstract: P-Channel MOSFETs are well known for their physical limitations compared to the N-Channel MOSFETs. Hole mobility is around three times smaller than electron mobility. Therefore a larger active area is necessary to achieve the same RDS(ON), thus making P-Channel devices more expensive. But they are equally known for their simplicity of usage. For applications in which a high side switch is needed, P-Channel MOSFET are the easiest option for their simple driver IC architecture and simple external circuitry, reducing the number of elements in the system. In this paper we will analyze the current and future usage of PChannel MOSFETs.
	Requirements for MOSFETs in Fuel Cell Power Conditioning Applications   By Dieter Polenov, Heiko Mehlich, Josef Lutz	[View]   [Download]
Abstract: Fuel cell power conditioning systems consist of one or several voltage converters as well as energy storage devices. For generation of required voltages and controlled energy transfer appropriate converter topologies are necessary. Low-voltage power MOSFETs often can be used as switching devices for such converters. Possible ways of utilisation of low-voltage MOSFETs in different topologies and the resulting requirements are discussed.
	Sensorless Control of Induction Motor Drives by New Linear Neural Techniques   By Maurizio Cirrincione, Marcello Pucci, Giansalvo Cirrincione, Gerard-Andre Capolino	[View]   [Download]
Abstract: This paper summarizes the research activity of the authors in the field of sensorless control of induction machine drives based on new linear neural techniques. In particular it describes and compares three speed observers: the MCA EXIN + MRAS Observer, the MCA EXIN + Reduced Order Observer and the TLS Full-order Luenberger Adaptive Observer. Common to all of three observers is the on-line estimation of the speed by a new linear neural technique, which solves in a recursive way a Total Least-Squares problem: one of them employs the TLS EXIN neuron and the other two the MCA EXIN + neuron, which is an improvement of the former. The speed observers have been verified in numerical simulations and experimentally on a test setup and have been also compared experimentally with one another.
	Sensorless Control of PM Synchronous Motors in the Whole Speed Range Including Standstill using a Combined INFORM/EMFModel   By Manfred Schroedl, Matthias Hofer, Wolfgang Staffler	[View]   [Download]
Abstract: The paper presents the combination of a lowspeed model (“INFORM method”) and a specially adapted high speed model (“Voltage model or EMF model”) for covering the full speed range of sensorless permanent magnet (PM-) synchronous motor drives. Both models generate “measuring information” for a linear observer, modelling the mechanical structure of the motor. A special feedback loop is introcuded, coupling back the observer information to the integrating voltage model. Thus, a stable operation with high robustness against parameter uncertainties and low frequency disturbances is achieved.
	Some Recent Results for Continuous Switched Linear Systems   By Victoriano Carmona, Emilio Freire, Enrique Ponce, Francisco Torres, Javier Ros	[View]   [Download]
Abstract: The elemental structure arising from the continuous autonomous switching of two linear systems is considered. After introducing certain canonical forms, some analytical results about limit cycle bifurcation are reported, showing that such systems generically exhibit a jump transition to oscillating behavior. Explicit expressions for quantitative characteristics of the periodic oscillation are obtained for the cases of dimension two and three. As another relevant result, it is shown that continuous ndimensional switched linear systems whose both components are Hurwitz need not be globally asymptotically stable when n is greater or equal to 3.
	Steering Chain HIL Simulator for Steer-by-Wire Systems   By Carlo Bernard, Silverio Bolognani, Luca Peretti, Mauro Zigliotto	[View]   [Download]
Abstract: Advanced control for automotive is one of the most promising research topic in the forthcoming decade. Actually, the long-term target is the substitution of most hydraulic car systems with their electronic counterparts. A bright example is set by the steering function, which has passed from pure mechanical to power assisted and recently to pure electrically power assisted function. The next step, the full electronic steering (Steer-By-Wire, SBW), is in progress. Definitively, it is going to substitute the mechanical connection with the steering wheel by wiretransmitted digital signals to one or more remote electric motors. Obviously, any innovative control strategy needs thorough hardware verification. At the early stages, or whether a real car prototype was not available, it is common practice to use hardware-in-the-loop (HIL) simulators, for fast control prototyping. In this frame, as proposed here, a high dynamic electric drive can virtually reproduce the real nonlinear load, represented by the steering chain and other external torque contributes. The paper presents the model details, the system architecture as well as the experimental validation of the complete HIL simulator.
	Switched Reluctance Turbo-Generator for Exhaust Gas Energy Recovery   By Melanie Michon, Stuart D. Calverley, Richard E. Clark, David Howe, Mike Mc Clelland, Paul Sykes	[View]   [Download]
Abstract: The paper describes a comparative study of low voltage and high voltage SR machines for use in an automotive turbo-generator exhaust gas energy recovery system. Their relative merits, in terms of the total machine loss and the loss distribution, are quantified. It is shown that the requirement for an integer number of turns imposes severe restrictions on the design of the low voltage system, whereas the flexibility to employ various winding designs in the high voltage system can be exploited to advantage. A comprehensive analysis of both the winding design and the operating control angles is presented. While the magnitude of the total machine loss is relatively insensitive to the operating voltage, the copper loss at full load is significantly lower in the high voltage system. The merits of operating the system at high voltage, in terms of the thermal rating of the electric machine, are also discussed.
	The BDFM as a Generator in Wind Turbines   By Richard Mc Mahon, Xiaoyan Wang, Ehsan Abdi-Jalebi, Peter Tavner, Paul C. Roberts, Mariusz Jagiela	[View]   [Download]
Abstract: The Brushless Doubly-Fed Machine (BDFM) is attractive for use in wind turbines, especially offshore, as it offers high reliability by virtue of the absence of brushgear. Critical issues in the use of the BDFM in this role at a system level include the appropriate mode of operation, the sizing of associated converter and the control of the machine. At a machine level, the design of the machine and the determination of its ratings are important. Both system and machine issues are reviewed in the light of recent advances in the study of the BDFM, and preliminary comparisons are made with the well-established doubly fed wound rotor induction generator.
	The Chattering Analysis   By Vadim Utkin, Hoon Lee	[View]   [Download]
Abstract: This paper presents analysis of the chattering and a new approach of the chattering suppression. The chattering caused by the unmodeled dynamics is discussed and analyzed by the Lyapunov method and the describing function approach. It is shown that the amplitude of chattering depends on the magnitude of discontinuous control. To reduce the chattering, new sliding mode control design is proposed using the methods of changing switching gain along the system states or the magnitude of equivalent control. To support the methods, simulation results are provided.
	Three Dimensional Discrete Map for a Single Inductor Current Mode Controlled Dual Switching DC-DC Converter   By Vanessa Moreno, Luis Benadero, Abdelali El Aroudi, Roberto Giral, Javier Calvente	[View]   [Download]
Abstract: A 3-dimensional discrete model of a single inductor switching dc-dc converter is obtained in order to explain bifurcations observed after the period 1 dynamics instability. Although a one dimensional model, using the inductor current as a state variable, predicts the first main bifurcation, the voltage of both positive and negative outputs cannot be assumed to be constant to give a more accurate prediction of the subsequent bifurcations, so two more state variables should be used.
	Traction Control for a PM Axial-Flux In-Wheel Motor   By Vincenzo Delli Colli, Fabrizio Marignetti, Roberto Di Stefano, Giovanni Tomassi, Maurizio Scarano	[View]   [Download]
Abstract: The traction control is a tool to increase stability and safety of vehicles and it has a greater performance potential in electrical vehicles than in ICV. Moreover, the traction control allows the EV to operate more efficiently preventing slippage in acceleration and permitting the use of high-efficiency low-drag tires. The presented approach can compete with the well-established techniques, but it offers a lighter tuning procedure. This paper presents an approach to the longitudinal control of a single wheel adopting a configuration based on an adherence estimator and a controller of the adherence gradient. The presented approach allows tracking of the value of the adherence derivative in a wide operating range without any knowmledge of the road conditions. The work is based mainly on experimental tests. The test rig computes the vehicle dynamics in real-time and loads accordingly the drive under test. The controller was experimentally verified showing good behavior.
	Transient Field-Circuit Coupled Models of Electrical Actuators   By Herbert De Gersem, Galina Benderskaya, Thomas Weiland	[View]   [Download]
Abstract: For simulating electrical energy transducers, transient 3D finite-elements models are used. Since the behaviour of electrotechnical devices is highly influenced by the driving electrical network, such models have to be extended by circuits. This paper discusses advanced fieldcircuit coupling techniques, models for the coils appearing in the finite-element model and appropriate solution techniques. Moreover, switching elements such as e.g. diodes and thyristors, are considered.
	Use of Doubly Fed Reluctance Machines In Wind Power Generation   By Erich Muschka Schulz, Robert Eric Betz	[View]   [Download]
Abstract: This paper discusses the developing electrical needs for wind tower generators (WTGs), and highlights the merits of brushless doubly fed reluctance machine (BDFRM) for these applications. There is a brief development of models for the doubly fed induction generator (DFIG) and BDFRM generator. These models show their similarities and how the BDFRM can be used instead of the DFIG, with the added benefits of brushless operation.