Please enter the words you want to search for:

EPE-PEMC 2002 - Topic 08: Electrical Machines and Actuators
You are here: EPE Documents > 04 - EPE-PEMC Conference Proceedings > EPE-PEMC 2002 - Conference > EPE-PEMC 2002 - Topic 08: Electrical Machines and Actuators
	[return to parent folder]
	A consistent mathematical model of the PMSM using the ficticious field current   By A. Thaler; B. Klöckl	[View]   [Download]
Abstract: A mathematical model of permanent magnet synchronous machines (PMSM), including iron core losses and saturating effects, is derived. It offers a theory for a more convenient handling of a synchronous machine with highly saturated reactances and relatively high leakage flux than with classical models. In this approach a highly reliable fundamental wave model for the PMSM is obtained that can be used for laboratory measurement interpretation as well as for control tasks in high-performance drive systems.
	A Multipole Asynchronous machines with mutually immovable windings   By L. Ribickis; N. Levin; M. Manonov; V. Pugachov	[View]   [Download]
Abstract: A multipole asynchronous machines is considered in which the primary and secondary windings are arranged on the stator, while the rotor is made tooth-like and without windings. Analysis of such machines is performed, and the main equations are obtained, which allow the parameters and performance of the machine to be calculated. The results of experimental investigations are presented for the physical model and comparison with the calculation data is given.
	A Predictive Voltage-Vector Selection Algorithm in Direct Torque Control of Induction Motor Drives   By A. Tani; G. Serra; C. Rossi; D. Casadei	[View]   [Download]
Abstract: An analysis of the torque ripple in Direct Torque Control (DTC) of induction motor drives is carried out by linearizing the machine equations around a steady-state operating point. The low number of voltage vectors available in each cycle period for compensating the torque and flux errors, is responsible for torque and flux variations. A new DTC technique based on the application of Space Vector Modulation (SVM) with prefixed duty cycles for improving the drive performance is presented. In this way it is possible to synthesize a higher number of voltage vectors without the need of timers and PWM signal generators, preserving the basic feature of DTC. A predictive algorithm is used to select the most opportune voltage vector sequence for the compensation of torque and flux errors. Numerical simulations and experimental tests are presented for validating the proposed control technique
	A Simple Way to Lower Transient I2R Losses in Small Induction Motor Drive   By J. Zadrozny; J. Zadrozny	[View]   [Download]
Abstract: The electrical machine apparently is the object of parametric oscillations. If so, the parametric resonance may occur. This phenomenon, at one time observed in small induction motor [1], in Authors’ opinion can be applied in some drives (e.g. start-stop duty) in order to lower effectively the transient I2R losses in windings and smoothing out the torque transients.
	Analysis of a Single-Sided Linear Induction Motor Drive Performance   By M. Bugeza; R. Fiser	[View]   [Download]
Abstract: Linear induction motors can very effective operate in automotive control systems, which require for an optimal operation the detailed insight in the steady-state and dynamic performance characteristics of the motor. This can be very effectively studied and evaluated on the base of mathematical modelling and computer simulation. The paper presents the analysis of linear induction motor operational performance based on the results of finite element method magnetic field calculations. The distinction between mathematical models of the rotary and linear induction motor is emphasized, several control strategies of the drive were examined and compared due to the dynamic response.
	Analysis of Squirrel Cage Induction Motor Performance Using a Prototype Based on DSP   By D. Zambra; S. A. Mussa; F. Salvadori; G. Villar; J. A. Moor Neto; N. C. De Jesus	[View]   [Download]
Abstract: This work describes the development of a prototype controlled by a system based on a DSP (Digital Signal Processor) that is dedicated to carry out an analysis of the performance of three-phase induction motors based on information’s obtained in manufacturer’s bulletin data of the three-phase squirrel-cage, on mensuration of speed and mensuration of voltages. Results of experimental tests that were accomplished are presented.
	Application of Newton-Raphson Method Combined with Analytical Equations for Determination of the Induction Motor Equivalent Circuit Parameters   By V. Boras; S. Berberovic	[View]   [Download]
Abstract: This paper describes application of modified Newton-Raphson method combined with analytical equations for determination of equivalent circuit (EC) parameters from the motor performance data. In this procedure, two of the total seven EC parameters are estimated using well-known analytical expressions. Values for the five remaining parameters are calculated iteratively using the reduced five-parameter Newton-Raphson method. For obtaining more accurate results, the EC parameters estimated in such a way are taken as new initial estimates for the seven-parameter Newton-Raphson model. The calculation results are compared with measurement results. All the errors in determination of EC parameters obtained by such model are within an acceptable range.
	Application, Calculation and Analysis of the Doubly Fed Longstator Linear Motor for the Wheel-on-Rail NBP Test Track   By H. Grotstollen; B. Yang	[View]   [Download]
Abstract: At the University of Paderborn a mechatronic railway system is developed, at which autonomous shuttles are guided by ordinary wheels and rails and driven by a doubly fed linear motor. The primary (i.e. stator) is installed between the rails, and the secondary (i.e. rotor) is fixed below the undercarriage. In this paper the modelling, calculation and analysis of a prototype of such a linear motor on a scale 1:2.5 are described in detail. Finally, the distribution of primaries along the NBP test track is also illustrated.
	Braking Operations of Electrical Drives Including Asynchronous Motors   By D. Iannuzzi; O. Veneri; L. Piegari; E. Pagano	[View]   [Download]
Abstract: The paper deals with braking operations of electrical drives including asynchronous machines operating either on active or on passive electrical networks. A short preliminary reference is made to theoretical backgrounds and, then experimental results referring to a sample drive are shown to explain and underline the more interesting and peculiar characteristic that have been envisaged and to show how specific driving algorithms of power converters can give rise to very efficacious braking actions.
	Characterisation of Kouznetsov Single-Phase Oscillating Linear Parametric Motor   By V. Tomachevitch; D. Hedjazi; R. Abdessemed	[View]   [Download]
Abstract: This article describes the operation, the structure and the basic characteristics of a motor working in a mode of electric and mechanical resonance. The core of the coil is operating on direct-reverse linear displacement. The oscillation thrust is improved by introducing a magnetic circuit to canalise the field lines.
	Compact Motors and Drives for Electric Vehicles   By G. Knerczer; P. Korondi; S. Peresztegi; L. Nagy; T. Mezo	[View]   [Download]
Abstract: Because of their high efficiency, brushless PM rotor motors are very suitable for vehicle drive application. This paper presents experiment results of a newly developed technique in brushless motors. It is suitable for both square current and DSP-controlled sinusoidal current drives. The experiment result of such systems is described. The drive systems, including the inverter, the motor and the controlling software, have been developed by the authors. Also, popular controlling algorithms have been used, and a common way to initialise them in order to enable them to work with any kind of motors.
	Computation of Magnetic Force Developed by Linear Synchronous Motors Based on Finite-Element Method   By F. Tóth; N. Szabó	[View]   [Download]
Abstract: The average thrust of the linear synchronous motors (LSM) is computed on the basis of a two-dimensional Finite-Element Method (FEM), when considering the iron and the permanent magnet non-linearity. The LSM under consideration consists of the short-primary and the long-secondary parts in various structures. The following secondary configurations have been taken into consideration: salient poles with field winding, reluctance type secondary and the equivalent of cylindrical excited form, permanent magnet segments where one was built with of surface mounted permanent magnets and one with buried permanent magnets. We compared the thrust and the attractive force at the aforesaid four motor types.
	Computer Aided Dynamic Regime Analysis of Electric Machines   By G. Atanasiu; C. Sorandaru	[View]   [Download]
Abstract: A discipline included in a curriculum of a technical high education has in general three tuition forms: lectures, seminars/laboratories and project. In spite of all the positive results of the current methods, we must agree that stress must be shifted on the active participation of the students in their own instruction process. This demand can be accomplished by the introduction of the computer technique, which meets these requirements. In this context the simulation method become a new tuition form in the educational process. In this paper we present the implication of introduction the simulation technique for the electric machines discipline, using the digital computer device.
	Design and Analysis of a Permanent Magnet Generator in the Steady State Load Conditions   By L. Susnjic; Z. Haznadar; D. Ban	[View]   [Download]
Abstract: This paper presents design and analysis of the permanent magnet generator (PMG) based on the magnetic field computation taking the external electrical circuit coupling into account. 2D (two-dimensional) transient finite element time stepping analysis at imposed speed are applied. The excitation of the PMG is achieved by Iron-Boron-Neodymium rare earth magnets (NdFeB) mounted into the rotor slots. The permanent magnets (PMs) flux leakage is minimized. Measurements on the experimental machine are included.
	Design Considerations of an Axial Flux Permanent Magnet Machine with U-Shaped Stator   By E. Peeters; P. Van Tichelen	[View]   [Download]
Abstract: This work discusses the design considerations, both analytical and by finite element analysis, of an axial flux permanent magnet synchronous machine with U-shaped stator, which is specially designed to have a simple robust construction with a low weight-to-power ratio, high efficiency and a controlled output voltage over a wide speed range. A mono-phase prototype was build. The results of the tests on the prototype are presented and the effects of different design parameters on the output of the machine are shown.
	Design Method of Reluctance Synchronous Motor with Axially Laminated Rotor   By P. Rafajdus; V. Hrabovcová; M. Franko; J. Mihok; P. Hudák	[View]   [Download]
Abstract: The paper deals with design procedure developed for the reluctance synchronous motor (RSM) with axially laminated rotor. The key diagrams showing relationship between all important design parameters are presented. The parameters of the RSM with really produced axially laminated rotor have been investigated and compared with calculated ones. The coincidence is very good. The measurements at full load condition confirmed the improved RSM performances.
	Design of a High Power Density Electromagnetic Actuator for a Portable Braille Display   By T. Nobels; F. Allemeersch; K. Hameyer	[View]   [Download]
Abstract: Refreshable Braille displays are generally large and expensive. This paper presents the design of a small and inexpensive linear electromagnetic actuator, which allows a considerable reduction in size and cost of refreshable Braille displays. The actuator concept is optimised with electromagnetic finite element simulations, which are verified with measurements on a prototype.
	Design rules for min cogging torque in a permanent magnet motor   By E. Bozeva	[View]   [Download]
Abstract: In a permanent magnet motor a cogging torque manifests itself by the tendency of the rotor to align in a number of stable positions when unexcited. Under dynamic conditions the resultant pulsating torque, of zero net value, may cause undesirable speed pulsation, and also may induce vibrations and acoustic noise. It is thus of great interest to get a deeper understanding of the cogging torque phenomenon and to find possible ways to reduce it. In an earlier paper a new design rule, Design rule 1 for normal motors, was demonstrated for a rotor design with slot mounted or embedded magnets. If the quantity Në, the relative magnet width compared to the slot pitch, is chosen as an integer (n), the cogging torque will be significantly reduced by a factor of ten or more to less than 0.5% of the rated torque. This can also be given a physical explanation. Here a complementary Design rule 2 is described for skewed motors, where the rotor is split into two equal parts that are displaced half a slot pitch to each other. If the quantity Në, the relative magnet width compared to the slot pitch, is chosen to (n+1/2), n being an integer, the cogging torque will also be significantly reduced to less than 0.5% of the rated torque. We show that this rule can be understood as a consequence of rule 1 for skewed rotors. Design rule 2 is to be used in cases where a motor according to Design rule 1 is not suitable because of a too low rated torque. The two rules have been verified by experiments on two different motors. The agreement between measurements and calculations of the cogging torque as a function of the rotor angle is good both for an un-optimised skewed rotor design as well as for an optimal normal design with an integer relative magnet width.
	Determination of Parameters in Jiles-Atherton Model from the Family of Hysteresis Loop   By J. Wlodarska; Z. Wlodarski	[View]   [Download]
Abstract: Optimization of parameters in Jiles-Atherton model is difficult because of the differen-tial implicit form of basic equation. Proposed by the authors of the model a numerical determination of parameters is based on some characteristics of the initial magnetization curve and major hysteresis loop. The proposed procedure takes into account the whole family of hysteresis loops corresponding to successively increasing amplitudes of alternating voltage. According to this, model parameters are chosen in such a way that the sum of the squares of relative differences between the calculated and empirical values of field and induction amplitudes, effective coercivities and hysteresis losses for the considered loops are minimized. More accurate results can be achieved by the optimization of parameters to each loop separately.
	Development of low permeability transformer based on polymer bonded magnetic materials   By C. Y. Tang; Y. Lu; Y. L. Ho; D. K. W. Cheng; K. W. E. Cheng	[View]   [Download]
Abstract: A new material to construct a transformer is present here. This is a polymer bonded magnetic material which has a low permeability. The material has certain advantage compared with the classical magnetic materials such as power iron and ferrites because it is very easy to make and not brittle. Usually injection moulding can be used to prepare the material whereas the other material such as ferrites requires a press machine and high temperature oven. This new material has been tested against its characteristics in energy conversion, B-H curve and loss. A modelling method based on probability density function to represent alignment is used to model the core. A transformer using this material has also been made and used in a DC/DC power converter. Experiment result has shown that high efficiency can be obtained.
	Direct Torque Control with Space Vector Modulation (DTC-SVM) for Permanent Magnet Synchronous Motor (PMSM)   By F. Blaabjerg; M. P. Kazmierkowski; D. Swierczyrski	[View]   [Download]
Abstract: This paper presents digital signal processor (DSP) based cascade speed control scheme with subordinated direct torque and flux control loops (DTC) for permanent magnet synchronous motor (PMSM) drives. Contrary to well-known Takahashi and Nogouchi approach which is based on hysteresis controllers and switching table, the described scheme uses PI controllers and space vector modulation (SVM) to generate switching pulses for power transistors of voltage source inverter supplying the PMSM. The presented control strategy DTC-SVM is implemented in software of the DS1103 board. Simulations and experimental results well demonstrate the effectiveness of the described control scheme. Also comparison with conventional DTC scheme and results of speed control loop are given.
	Effects of Stator and Rotor Slottings on the Performance of A New type of Converter- fed Synchronous Motor drive/system   By N. R. Abjadi; J. Soltani	[View]   [Download]
Abstract: In this paper, the theory of operation of a new type of converter-fed synchronous machine drive is discussed first, which is capable of controlling the stator current waveforms to a shape which can be decided by the designer. Then, the Schwarz-Chirstoffel transformation (used in obtaining the Carter’s coefficient) is utilized to obtain the airgap permeance models of a six-phase design of the above machine drive types. The models are due to the stator slots effects with smooth rotor and vice versa. The machine drive was designed and built with a 225 frame and a slip-ring induction motor rotor in order to produce the stator current waveforms an approximate to sine-wave. A step by step computer program was developed to model the machine drive/system on PC. The simulated and practical results obtained are in a close agreement.
	Electro Magnetic Variation Controlled Gear with Integrated Clutch Function   By A. Thaler; R. Surtmann	[View]   [Download]
Abstract: In thermodynamic motor systems, mechanic elements of power transmission are substituted by electro – mechanical respectively purely electrical designs. In the drives sector there is an effort to vary the gearing ratio stepless in dependence of the load to accomplish highest efficiency of the drive assemble. It is possible to comprise the force transmission, the mechanic clutch, the gearing and the function of a mechanical differential into one gearbox. This gearbox includes electrically excited magnetic coils and permanent magnets in yokes. The gearing ratio is adjustable in defined steps. This paper describes an overview of the elements of the Electro – Magnetic Gear (ELMAG), first results of measurements on the new concept of poles arrangement and the calculation of torque.
	Experimental Evaluation of a Two-phase Axial Flux Circumferential Current (AFCC) Permanent Magnet Machine   By R. Qu; J. Luo; S. Huang; T. A. Lipo	[View]   [Download]
Abstract: After a summary of the single-phase Axial Flux Circumferential Current (AFCC) machine, a two-phase AFCC machine is presented to reduce the high pulsation torque of a previous single-phase topology. A prototype of the two-phase AFCC machine is discussed. The experimental analyses of the prototype are presented. The results show that coupling of two phases is a valid method to reduce the large pulsation torque related to the single-phase topology, while the torque capability is still kept high. Powdered iron material is employed in the prototype to accommodate the three-dimensional flux distribution in the stator and rotor. The iron losses of the material are reported.
	Genetic algorithm based design of current control for a PMSM   By D. Samuelsen; W. Sulkowski; T. Dragset; P.-O. Nyman	[View]   [Download]
Abstract: A current controller for a permanent magnet synchronous motor is designed for optimal robust performance under uncertainties in the stator parameters. To avoid conservatism inherent in LMI-and H-infinity type methods, a genetic algorithm is used for the optimization. The controller structure is composed of two PIcontrollers and a dynamic decoupling precompensator. Evaluation of simulated step responses suggests that better performance is achievable with this approach, than with an earlier LMI-based approach.
	High performance permanent magnet synchronous machines for traction applications   By P. Woditschka; F. Aschenbrenner	[View]   [Download]
Abstract: Permanent magnet synchronous machines (PMSM) have compared with asynchronous engines a better utilization factor (torque per mass), a better power factor and a higher efficiency especially when high energy magnets (rare-earth-materials such as NbFeBo or SmCo) are used. The price of the magnets is still a major cost-factor of the machine, but the price decreases considerably when advanced and cost-optimized mass-production procedures are used in magnet production. Therefore it is reasonable to use this type of machine for new applications e.g. in electric cars (zero emission vehicles), boats or micro-power-stations as well. At the research department of the University of Leoben detailed investigations about this type of electrical machine has been done (including prototyping and testing). Motors for different applications and in a variety of nominal powers have been developed in cooperation with industrial partners. One of the main objectives is to optimize the machine for the mentioned applications. This paper describes an optimization of the motors geometries with respect to cost, weight and efficiency for usage in electric vehicles.
	Identification of Induction Motor Parameters from Free Acceleration Test Measurements   By M. Jadric; B. Terzic; M. Despalatovic	[View]   [Download]
Abstract: This paper describes a method for estimating the parameters of a three-phase induction motor using the measurements of the stator line voltages and currents during startup transient. The identification method presented minimizes errors in the observed properties of loss functions in the least-squares sense using a Levenberg-Marquardt method. A special procedure that provides very good initial estimates of the motor parameters is presented. The parameters obtained using the identification method are compared with ones obtained from standard tests.
	Identification of the Parameters of Induction Machine   By A. Lazhar; N. Farid	[View]   [Download]
Abstract: A parameter identification method is designed for a fifth order of an induction motor, which includes both electrical and mechanical dynamics. For the parameter identification a non-linear optimization is used and the convergence of the identification algorithm is investigated. Full state measurements are required.
	Implementation of Fuzzy Controller for DC-Servo Drive Using a Low-cost Microcontroller   By E. Akpinar; S. Pravadalioglu	[View]   [Download]
Abstract: New fuzzy microcontroller chips are available on the market and able to execute fuzzy rules very fast with their mask programmed algorithms which has some drawbacks such as restricting to choose desired algorithms. Most of the DSP integrated circuits (IC) do not contain some peripherals such as Analog to Digital (A/D) converter and Pulse Width Modulation (PWM) circuits on chip and need to be added externally. This paper introduces a fuzzy logic controller (FLC) for a permanent magnet dc motor drive using a low-cost microcontroller. The presented FLC application calculates the duty cycle of the PWM chopper drive, has a good performance and can be used to dc-dc converters as well. The Matlab simulation and experimental test results are given . The contribution of this paper is to present the feasibility of a high performance nonlinear controller which can be inexpensively implemented with a low cost microcontroller.
	Improvement of LSRM Tracking at Low Speed Operation   By G. Stumberger; D. Dolinar; M. Milanovic	[View]   [Download]
Abstract: The paper deals with the modeling and control design of a linear synchronous reluctance motor (LSRM). To improve the results of kinematic control at very low speed the standard input{ output linearizing control is modied introducing the new nonlinear dynamic LSRM model. The experimentally determined ux linkages given as functions of the direct and the quadrature axis currents are used in the model to take into account the iron core nonlinearities. The presented results obtained by the proposed input{output linearizing control based on the modied LSRM model have shown the signicant improvement of the tracking performances in comparison to the classical cascade control.
	Inductance Calculation in Switched Reluctance Motors   By I. Hajdarevic; H. Köfler	[View]   [Download]
Abstract: Switched Reluctance motors are candidates for a wide variety of drive applications. Their description is most often reduced to the simple concept of I characteristics. In contrast to this the machine itself is a real electrical machine and for its correct simulation in Calculation schemes for stationary and transient operation several individual Inductance values of the machines are necessary [1]. In a brief introduction the ideas behind Inductance Calculation in electrical machines are reviewed. On two in cross section identical SWR machine models the Calculation of Inductance values is performed and compared with the experimental readings. Some of the shortcomings of either of the presented methods and possible ideas to overcome the shortcomings are discussed.
	Induction generator output voltage and frequency stabilization   By A. E. El Sabbe; A. S. Zein El Din	[View]   [Download]
Abstract: Poor voltage regulation is one of the major drawbacks of an isolated self-excited induction generator. The terminal voltage may increase considerably due to a small increase in speed. This paper introduces, a new technique for induction generator speed control is used. D-C to D-C chopper is used for controlling a d-c motor input voltage, coupled to the shaft of Induction Generator. A simple converter with only two legs is required, each leg consists of IGBT and fast recovery diode, one leg connected in series with armature of d-c motor while the other connected in parallel with d-c motor terminal. Simulation and Experimental study of different conditions of d-c to d-c chopper fed d-c motor are obtained, and hence braking terminal voltage of Induction Generator is carried. All parts (voltage and current) of the proposed system are investigated. Closed loop control of terminal voltage of a stand-alone induction generator is presented by using bang-bang control of d-c to d-c chopper, and hence brakeing of Induction Generator is achieved. A good agreement between simulation and experimental results are found.
	Induction machine testing using PROFIBUS industrial communication network   By Z. Simunic; I. Gasparac; M. Vrazic	[View]   [Download]
Abstract: New technologies (in this case PROFIBUS) enable new approach to known problems. One of such problems is monitoring and on-line machine testing. With PROFIBUS it is possible to achieve full automation of induction motor testing process. Also it is possible to analyse the results and produce necessary documents. This paper describes usage of PROFIBUS industrial communication network in induction motor testing.
	Induction Motor Stator Faults Diagnosis using Neural Networks   By T. Orlowska-Kowalska; C. T. Kowalski	[View]   [Download]
Abstract: The paper deals with the diagnostic problems of the induction motors in the case of stator faults. For diagnostic purposes two kinds of neural networks were proposed: multilayer perceptron networks and self organizing Kohonen networks. Neural networks were trained and tested using measurement data of axial leakage flux and mechanical vibration spectra. The efficiency of developed neural detectors was evaluated. Feedforward NN with very simple internal structure used for the detection of fault kind gave satisfactory results, what is very important in practical realization. Experiments with Kohonen networks indicated that they could be used for initial classification of motor faults, as a introductory step before proper neural detector based on multiplayer perceptron.
	Low-Noise EC Motor with External Rotor for Automotive Application   By M. Schier; A. Lelkes	[View]   [Download]
Abstract: For the development of a new, long-life and low-noise motor for automotive applications, several motors with different constructional features were built, analyzed and compared. The utilization of the experimental results made it possible to develop an electronically commutated, external rotor motor with very low acoustic noise. The new motor is used for axial and centrifugal fans for omnibus air conditioning.
	Magnetic field determination in a motor with slots using conformal mappings   By M. Markovic; M. Jufer	[View]   [Download]
Abstract: An original analytical method to determine the 2D magnetic field in a rotating motor with a smooth stator, and a slotted rotor is presented. The field is due to a coil with a current, placed in the air gap. Based on this method, the 2D magnetic field in a permanent magnet (PM) motor can be determined. The method is based on the complex conformal mapping theory. Using two steps, the given configuration of the rotating motor is transformed in a simpler configuration, in which the magnetic field can be solved analytically. Knowing the magnetic field in the motor, its main characteristics, such as torque, cogging torque, fluxes and back-emf can be easily found.
	MMF of High Phase Order Induction Motors for Different Shapes of Supply Voltages and Currents   By J. Grochowalski	[View]   [Download]
Abstract: The analysis and modeling of magnetic field of a multiphase induction motor are presented. In particular, the effects of high phases growing to infinity are studied. This paper describes analysis and computer experimental results of MMF in multiphase AC machines supplying by sinusoidal and nonsinusoidal currents and voltages. Author proposes to use magnetic field for infinity phases as a reference to synthesis and comparison of the multiphase AC machines.
	Neural Network and Genetic Algorithm as a New Approach in Design Optimization of Induction Machines   By A. Tokic; I. Kapetanovic; Z. Haznadar; V. Madzarevic; S. Berberovic; J. Smajic	[View]   [Download]
Abstract: A new approach for optimization of induction machines is presented in this paper. This algorithm is based on the neural networks and genetic algorithm. Neural networks are used as a tool for prediction of induction machine characteristics with respect to induction machine geometrical variables. The optimization process is based on genetic algorithm, as a method from the category of probabilistic algorithms. Optimization algorithm is tested on the optimization of double-cage induction machine starting characteristics. Numerical calculations of induction machine starting characteristics, as an important part of this algorithm, are performed using finite element method for electromagnetic field computation inside of induction machine. Results of electromagnetic field computation are used for synthesis of induction machine equivalent circuit. Full algorithm for calculation of induction machine starting characteristics is developed and named as “voltage balanced iterative process”. Results of starting characteristics calculation are compared with results of experimental measurement. Result of optimization process is induction motor with better starting performances.
	Nonlinear Modelling of Switched Reluctance Motor   By O. Rabulea; L. Zarnescu; V. Trifa	[View]   [Download]
Abstract: The aim of the paper is to develop a mathematical model of Switched Reluctance Motor, which includes the effect of magnetic nonlinearities. The starting point for the model is the double variation of the phase inductivity with the current and the position, experimentally measured. This variation is analytically described using different approximations: polynomial, exponential and trigonometric. An analysis and comparison of these methods is performed. A Matlab-Simulink implementation of the model is realized. A large palette of simulation results are given.
	On a High Force Modular Surface Motor   By I.-A. Viorel; L. Szabo	[View]   [Download]
Abstract: Surface motors are capable of fast and accurate two axes translation motion. It makes them useful for various industrial and laboratory applications. In this paper a new direct driven permanent magnet variable reluctance surface motor having high force mover modules is presented. The surface motor is capable of high position resolution, rapid acceleration and high speed on both directions with low mass payloads. The surface motor's structure and control possibilities are investigated and the dynamic behaviour of the motor is studied using MATLAB/SIMULINK.
	PM Coreless type Surface Motor   By H. Ohsaki	[View]   [Download]
Abstract: A novel surface motor with permanent magnets and coreless armature structure has been studied, which will be suitable for a small actuator used for two-directional drive and precise positioning. For such a surface motor two-dimensional extension of the Halbach array of permanent magnets is considered. FEM analysis has been carried out to study the fundamental characteristics of the motor and the Halbach-like permanent magnet array. The analysis results show that when the distance between adjacent N and S poles of permanent magnets is 7.5 mm, the Halbach-like permanent magnet array that is higher than 2mm can generate a higher magnetic field than a normal 2-dimensional array of permanent magnets. It is found from these results that a Halbach-like two-dimensional array of permanent magnets is effective for a coreless PM surface motor. In addition, there is an optimum value for the width of each permanent magnet for a designed gap length.
	Some Considerations on the Design Method of A Linear Parametric Motor with Double Driving Surfaces   By S. Kikuchi; T. Sekimoto; K. Ishikawa	[View]   [Download]
Abstract: This paper describes the considerations on the design method of a linear parametric motor with double driving surfaces. The proportion of stator length and height (L / H) which maximized the static thrust was clarified experimentally and was confirmed by the FEM simulation. The static thrust increased at 2.9 times, when the stator core width was made to be the double.
	The Causes and Reduction of Rotor Bar Breakages in Large Squirrel Cage Induction Motors   By G. M. J. Parsley	[View]   [Download]
Abstract: This paper describes how the varying torque distribution around the periphery of the rotor of an induction motor was verified by using finite element analysis. This varying torque distribution is cited as the main cause of rotor bar breakages occurring near to the end rings of the rotor cage. A possible solution is offered.
	The coaxial transformer – the influence of primary winding shape on the transformer properties   By B. Grzesik; M. Stepien	[View]   [Download]
Abstract: Presented paper describes the results of analysis of the influence of primary windings shape on the coaxial transformer properties. The analysis contains two types of windings design. The first type called a “conventional” transformer and the second “two-pipe” one. Both types have the form of spiral where secondary is made of pipe inside of which the primary is placed.. The primary winding of conventional is a solid wire while the one of two-pipe is a pipe. Primary and secondary windings are coaxially arranged and located inside of the magnetic core. The analysis embraces calculations of the efficiency, power losses in the windings and magnetic core of the transformer and ratings calculated at given allowable total power losses in the transformer. Calculations were done using ANSYS software, based on finite element method (FEM).
	Torque Derivative Approach to the Direct Torque Control of Induction Motor   By K. Jezernik; M. Rodic	[View]   [Download]
Abstract: An interesting approach to the presentation of the Direct Torque Control (DTC) for the induction motor is presented in the paper. The main contribution of the work is the direct connection of the torque and fluxes with the applied stator voltage, which was established with the calculation of the torque derivative. Thus instead of indirect torque control through the rotor and stator, a direct torque control is performed. The procedure of the switching table creation is explained. The method enables the high-dynamic response to the changes of the desired values of both, flux and torque. Using this method, besides the well-known stator flux oriented DTC also the rotor flux oriented method is developed, presented and analyzed. The performance is investigated and verified with simulations and experiments.
	Torque Ripple Reduction by Optimal Power Supply for Saturated Synchronous Motors   By G. Sturtzer; D. Flieller	[View]   [Download]
Abstract: This paper presents a method to obtain the optimal currents which reduces the torque ripple to zero with minimal cooper losses. This method takes into account the magnetic circuit saturation. It applies to variable reluctance synchronous motors, excited or not excited. This method follows from the evolution of the operating point with constant torque and minimum copper losses in the Concordia frame.
	Torque Ripple Reduction in Switched Reluctance Motors by Pole Tip Shaping   By N. Guzelbeyoglu; M. Garip; E. Mese; Y. Ozoglu	[View]   [Download]
Abstract: High torque ripple is one of the major disadvantages of Switched Reluctance Motor (SRM). It is very well known that stator and rotor pole shapes are the key factors determining the level of torque ripple. This paper, in particular, suggests an approach adjusting some parameters related with stator and rotor pole tip shapes aiming to reduce torque ripple. Basic premise of the proposed method is to modify inductance profile in order to modify torque profile by shaping stator and rotor pole tips. As a first step, magnetization characteristics and torque profile of a conventional SRM have been obtained by solving the associated Finite Element Model (FEM). Then, some pole tip parameters have been defined in an effort to obtain the lowest possible torque ripple. Finally, conventional and proposed SRM have been compared and the influence of the proposed pole tip shapes on torque ripple and other performance parameters have been discussed. Five different stator and rotor pole tip structures have been investigated and compared with conventional pole tip. It has been observed that one of the proposed tip shape is capable of decreasing torque ripple from 36% in conventional SRM to 11.9%.
	Torsional Dynamics of Generator-Units for Feeding Induction Motor Drives   By M. Milkovic; Z. Maljkovic; M. Mirosevic	[View]   [Download]
Abstract: The paper analyses the torsional dynamics of generator-units for feeding induction motor drives. A unique mathematical model of the integral motor drive has been developed, consisting of: a diesel engine, a synchronous generator and a non-regulated motor drive fed directly from the generator-unit terminals. The validity of the mathematical model was checked by comparing the results of simulation and measurement on the generator-unit with a diesel engine of 46.4 kW and a synchronous generator of 40 kVA, to which a motor drive of 7.5 kW was connected.