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Electric Machines & Drives Conference, 2007. IEMDC '07. IEEE International

Date 3-5 May 2007

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    Page(s): iv - v
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    Page(s): vi - xxx
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  • Control Relevant Equivalent Circuit Parameters of a Squirrel Cage Induction Motor and Their Modern Finite Element Assisted Determination

    Page(s): 897 - 903
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    The realization of a vector control for the operation of induction motors often takes advantage of ordinary equivalent circuit models. These are usually based on a set of lumped resistive and inductive parameters for a substituted characterization of the real motor design. Some simplified models are consisting of a reduced number of system parameters and allow a very basically identification procedure by no-load tests in the lab. Fictive identification tests could fortunately be carried out by the finite element method during the development and optimization process, without the necessity of cost- extensive prototyping. Such numerically obtained equivalent parameters of projected motor designs are used within an even more complex simulation of the complete controlled drive system. Deviations between the numerically predicted controlled system behavior and the required features could be found and eliminated in advance. View full abstract»

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  • Loss Analysis of Interior Permanent Magnet Motors Considering Carrier Harmonics and Magnet Eddy Currents Using 3-D FEM

    Page(s): 904 - 909
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    In this paper, we investigate losses of interior permanent magnet motors driven by PWM inverters using the 3-D finite element analysis, which can estimate the eddy current loss in the permanent magnet accurately. The calculated losses are compared with the measured results and the theoretical solution to verify the validity of the analysis. The method to decompose the electromagnetic field distribution into time-harmonic components is introduced in order to investigate the effects of the harmonic fields separately and to specify the main loss factors. The variation of the magnet eddy current loss due to the division of the magnet is also investigated. It is clarified that the eddy current loss in the permanent magnet is mainly produced by the carrier harmonics of the inverter and that the axial length of the divided magnet should be smaller than the skin depth of the eddy currents produced by the major harmonics for the loss reduction. View full abstract»

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  • Equivalent Circuit Parameter Identification of Six-Phase Reluctance DC Machine Using Finite Element Method

    Page(s): 910 - 915
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    Abstract-In this paper a per phase equivalent circuit model of the reluctance DC machine is investigated. The equivalent circuit parameters are identified through finite element analysis for both no-load and load conditions. The model is verified by comparing, amongst other things, the torque calculated from the determined equivalent circuit with the torque calculated by the finite element Maxwell stress tensor method and the measured static torque of a 35 kW reluctance DC machine drive. It is shown that the equivalent circuit parameters are severely affected by the phase current commutation under full load and the armature reaction effect. View full abstract»

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  • Characteristics Analysis of Anisotropy Rotor SynRM Using a Coupled FEM & Preisach Model

    Page(s): 916 - 920
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    This paper deals with the characteristics analysis of Synchronous Reluctance Motor (SynRM) with anisotropy rotor using a coupled FEM & Preisach model. The focus of this paper is the design relative to the output power on the basis of rotor materials of a SynRM. The coupled Finite Elements Analysis (FEA) & Preisach model have been used to evaluate nonlinear solutions. Comparisons are given with characteristics of normal synchronous reluctance motor and those of anisotropy rotor SynRM (ANISO-SynRM), respectively. View full abstract»

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  • Comparisons in the Analytical, 2D and 3D Analyses of a Low-cost 2-Pole Permanent Magnet Commutator Motor

    Page(s): 921 - 926
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    The paper puts forward a full 3D finite element analysis (with transient solutions), a 2D finite element analysis (with magneto-static solutions) and an analytical analysis of a small 2-pole commutator motor with three armature slots and coils. These machines are very common low-cost machines but the amount of recent literature on their design (using modern CAD packages) is quite small. The results illustrate the cogging nature of the torque and also the drawbacks in the 2D finite element analysis. Various design changes are investigated using the different analysis techniques to illustrate that even small motors can be improved by careful addressing of some important design features. These improvements include slot opening variation and the use of different magnet material. A thermal solution is carried out to ensure that it does not overheat. View full abstract»

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  • Coil and Magnet Shape Optimization of an Ironless AFPM Machine by Means of 3D FEA

    Page(s): 927 - 931
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    Coreless permanent magnet (PM) machines can be a viable solution for applications where light-weight and high- efficiency are requested, as the absence of an iron core in the stator reduces machine weight and losses at high-frequency losses. Due to the large airgap, main flux is not driven by a magnetic path into the stator, hence a 3D field analysis is necessary. In this paper, an AFPM ironless machine has been optimized in terms of maximum torque produced per joule losses. Several topologies of coils and magnets have been proposed and investigated with 3D FEA. View full abstract»

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  • High Performance Direct Torque Control of a PMSM using Fuzzy Logic and Genetic Algorithm

    Page(s): 932 - 937
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    This investigation improves the performance of a direct torque controlled permanent magnet synchronous motor (PMSM) using both genetic algorithm (GA) and fuzzy logic. In this approach electromagnetic torque error, stator flux linkage error and stator flux angle are fuzzified using three appropriate fuzzy sets. Therefore the best voltage space vector has been selected in order to minimize torque, flux and current ripples. In this paper direct torque control (DTC) of a PMSM drive is simulated using both conventional table based and fuzzy methods and the PI speed controller is tuned using GA. A comparative study between conventional DTC and proposed approach shows that not only the speed response of the controller has been improved but also torque, flux and stator current ripples have significantly been reduced without any effective change of the inverter switching frequency. View full abstract»

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  • Efficient Control of the Electrical Drives in the Transient State

    Page(s): 938 - 942
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    The optimal control of the linear electrical drive systems is presented. Certain previous results are extended. A simple implementable solution is proposed. Simulation and experimental tests are presented and a comparison with the usual cascade control is performed. View full abstract»

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  • Sliding Mode Power Control of Variable Speed Wind Energy Conversion Systems

    Page(s): 943 - 948
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    This paper addresses the problem of controlling power generation in variable speed wind energy conversion systems (VS-WECS). These systems have two operation regions depending on wind turbines tip speed ratio. They are distinguished by a minimum phase behavior in one of these regions and a nonminimum phase in the other one. A sliding mode control strategy is then proposed to ensure stability in both operation regions and to impose the ideal feedback control solution despite of model uncertainties. The proposed sliding mode control strategy presents attractive features such as robustness to parametric uncertainties of the turbine and the generator as well as to electric grid disturbances. The proposed sliding mode control approach has been simulated on a 1.5-MW three-blade wind turbine to evaluate its consistency and performance. The next step was the validation using the NREL (National Renewable Energy Laboratory) wind turbine simulator FAST (Fatigue, Aerodynamics, Structures and Turbulence code). Both simulation and validation results show that the proposed control strategy is effective in terms of power regulation. Moreover, the sliding mode approach is arranged so as to produce no chattering in the generated torque that could lead to increased mechanical stress because of strong torque variations. View full abstract»

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  • Virtual product development for electrical motors

    Page(s): 949 - 952
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4841 KB) |  | HTML iconHTML  

    In this paper, a software for virtual product development of electrical motors is introduced. Nowadays, consideration of electromagnetic, thermal and acoustic design aspects of electrical machines can be achieved by either using specialized or universal software packages. The specialized packages are predominantly developed for only one physical domains whereas universal software packages need to be adapted for the individual application. In both cases, the design engineer spends plenty of time, adapting or coupling software instead of developing an electrical machine. The software presented in this paper is specialized for the development of electrical machines and combines simulation tools for all mentioned physical domains. Furthermore, numerical and analytical methods are coupled to reduce computation time of typical numerical simulations and to increase the accuracy of analytical approaches. For the implementation, open-source components are used to reduce costs and to use well documented file-formats. Furthermore, the visualization component includes virtual reality capabilities. This specialized approach allows for a timesaving virtual design process of electrical machines. View full abstract»

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  • Swarm Intelligence-Based Controller of Two-Asymmetric Windings Induction Motor

    Page(s): 953 - 958
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    In this paper, applying field orientation based on Particle Swarm Optimization (PSO) controls the speed of two-asymmetrical windings induction motor. The maximum efficiency of the motor is obtained by the evaluation of optimal rotor flux at any operating point. In addition, the electro-magnetic torque is also improved while maintaining a fast dynamic response. In this research, a novel approach is used to evaluate the optimal rotor flux level. This approach is based on Particle Swarm Optimization (PSO). PSO method is a member of the wide category of Swarm Intelligence methods (SI). This research presents two speed control strategies. These are field- oriented controller (FOC) and FOC based on PSO.. The results have demonstrated that the FOC based on PSO method saves more energy than the conventional FOC method. View full abstract»

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  • A Flexible Electromagnetic Damper

    Page(s): 959 - 962
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    This paper introduces a new passive suspension system for vehicles. The system is based on a flexible electromagnetic damper. In the proposed system, it is attempted: a) to select a variable damping coefficient usable in a car; b) determine the physical dimensions and geometry of an electromagnetic damper to be not very different from mechanical dampers; and c) the weight and volume of the damper to be low and for the core not to be saturated. After designing and providing a model, the results of a test model are compared with the behavior of a tubular linear induction motor, connected to variable D.C. supply. This system will have low cost and be controllable. View full abstract»

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  • Analytical Analysis of Magnetic Field and Force Calculation in a Slotless-Type Permanent Magnet Linear Synchronous Machine; Verification with Numerical Analysis

    Page(s): 963 - 968
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (493 KB) |  | HTML iconHTML  

    This paper presents an analytical analysis of magnetic field in a slotless-type permanent magnet linear synchronous machine (PMLSM). For the verification, the numerical analysis (finite element method (FEM)) of magnetic field is accomplished and comparison between analytical and numerical solution of magnetic field is presented. Both analytical and numerical solutions are obtained by 2D analysis via magnetic vector potential, respectively. The paper also presents the comparison between analytical and numerical (FEM) solution of static thrust and normal force using Maxwell's stress tensor method. The verifications show that good agreement between analytical and numerical solution of magnetic field, static thrust and normal force is obtained. View full abstract»

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  • Control Strategies for Linear Synchronous Motors

    Page(s): 969 - 971
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3939 KB) |  | HTML iconHTML  

    Linear motors present both advantages and challenges when utilized to control vehicles on a guideway. Linear motors are superior to other means of propulsion in that force is applied directly to the vehicle, does not depend upon friction, is tightly controllable, and the linear motors themselves have no wearing parts. Use of linear motors does, however, present some unique challenges. The back EMF can vary with position as well as speed, the overall thrust constant can vary if there are gaps between the stators, and stators must be synchronized as a vehicle transitions from one to the other. Strategies for successfully managing these characteristics will be discussed. One of the key linear motor design parameters is the length of the stator that is energized, referred to here as block length. There are a wide range of strategies for sizing block lengths, ranging from individually driving each pole to driving kilometer long blocks. Tradeoffs for block length in terms of cost, efficiency, throughput, and reliability will be discussed along with specific strategies for one application. Methods for operating multiple vehicles safely under the constraints of linear motor block-based control will also be discussed. View full abstract»

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  • Optimum LIM Interval Selection of Vector Controlled Moving Secondary Plate Conveyor System Using FEM & SUMT

    Page(s): 972 - 976
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3003 KB) |  | HTML iconHTML  

    It is necessary to modify the state-of-the-art of speed control theory because of the phase asymmetry in the linear induction motor (LIM) and for the constant speed control of mover using single vector control inverter system, it is important that primary stack is located in appropriated intervals in the 3D conveyer system using LIM. The dynamic characteristic analysis method of the vector controlled LIM using coupled FEM and control algorithm taking into account the movement is proposed. The focus of this paper is the analysis relative to selecting primary stack intervals in order to constant speed control in the 3D conveyer system using LIM. View full abstract»

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  • A Direct Control Scheme to Achieve Maximum Acceleration in Linear Induction Motors

    Page(s): 977 - 982
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4244 KB) |  | HTML iconHTML  

    Linear induction machines (LIM) have shown their advantages in high speed propulsion in a variety of industries, such as, military, transportation, and aerospace to name a few. Usage of vector control to achieve maximum speed acceleration/deceleration for linear induction machines has been a focal area of research for the past decade. However, due to the trailing eddy current effects and magnetic asymmetry effects, vector control does not provide nearly the functionality for LIM as it does for rotary induction machines (RIM). Therefore, searching for an adequate control scheme with ease in implementation and low cost is the motivation for this paper. Using finite element analysis (FEA) the relationship between traction force and different ranges of linear speed and excitation frequencies in motoring, generating, and electromagnetic braking regions has been explored. By storing these characteristics in the form of lookup tables which provides excitation frequencies resulting in maximum accelerating and decelerating forces, a closed-loop speed control scheme with fast response has been proposed. View full abstract»

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  • Novel Permanent Magnet Tubular Linear Generator for Wave Energy Converters

    Page(s): 983 - 987
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    Clean and sustainable alternative energy is becoming attractive as oil costs rise and the negative side effects of traditional energy systems begin to become apparent. One often overlooked, but still rapidly growing alternative is wave power. There are fascinating new designs for harnessing the tremendous power of the waves. Hence any contribution in this field could be of real interest for numerous specialists. In the paper a novel modular permanent magnet tubular linear generator is proposed and analyzed by means of numeric field computations. It was designed for wave power take off systems to be placed in the Black Sea near the Romanian coasts. View full abstract»

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  • Design Optimization of Linear Induction Motor for Improved Efficiency and Power Factor

    Page(s): 988 - 991
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    Linear electrical motors (LMs) are increasingly used in industry applications to develop linear motion. However, they suffer from two major drawbacks i.e. low efficiency and low power factor which cause more energy consumption, a rise in input current and occupation of transmission lines capacity. This paper presents a multi objective optimization method to improve both efficiency and power factor, simultaneously. For this purpose, the analytical model of machine is employed to calculate the efficiency and power factor. Motor parameters and dimensions are then optimized using genetic algorithm and an appropriate objective function. The results show an enhancement in motor performance. Finally, time stepping finite element method is used to evaluate the analytical results. The comparison of results validates the method. View full abstract»

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  • The correct analytical expression for the phase inductance of salient pole machines

    Page(s): 992 - 996
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1483 KB) |  | HTML iconHTML  

    For the electrical machines with salient pole rotor topology, due to the rotor saliency, the self- and mutual inductance vary sinusoidally with the rotor position. In many literatures analogous to the non-salient pole machines often it is assumed that also for salient pole machines the phase inductance is a function of rotor position, since the self inductance of this type of machines depends on the rotor position. The aim of this paper was to investigate further the performances of this parameter. Deriving a correct formula for the total phase inductance for this type of electric machines shows that this parameter is constant with rotor position, and doesn't vary as is assumed in many literatures. The new expression for the phase inductance is validated by comparing with finite element method. View full abstract»

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  • Synchronous Machine Modeling and Analysis for Internal Faults Detection

    Page(s): 997 - 1002
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    In this paper, the modeling and analyzing of synchronous machines, when the single and double phase internal fault happens is explained. Results show recognition of faults that happen near the center of star connection of winding by means of ordinary traditional protections is very hard. Disability to detect those faults will reduce the usual life and performance of machine. Here, a new method for analysis and evaluating insensible short circuit is shown. View full abstract»

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  • Turbogenerator refurbishment with up-rating based on embedding stator damper winding and modern electromagnetic materials

    Page(s): 1003 - 1007
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    40 MVA two-pole air cooled turbogenerator has been up-graded with stator refurbishment only. Generator active power has been increased from 32 MW to 42 MW with reference to 31% and apparent power has been increased for 23.5%, from 40 MVA to 49.4 MVA. It was necessary to redesign stator core and winding, to embed the stator damper winding and implement new magnetic and insulating materials in order to reach new higher power. Redesigned stator core needs to be of the same outside dimensions as the original one, and to be placed in the old stator casing. Refurbishment requirements with remaining the original machine parameters (but higher output) such as synchronous reactance, audible noise level, voltage and frequency regulation, reactive power and temperature rise in insulation class B have been achieved. Impact of embedding the stator damper winding has been determined by finite-element analysis since the other parameters of refurbished generator have been calculated using analytical and finite element modeling. View full abstract»

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