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Energy Conversion, IEEE Transactions on

Issue 3 • Date Sep 2002

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Displaying Results 1 - 19 of 19
  • On the use of a simplified model for switched reluctance motors

    Page(s): 400 - 405
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (265 KB) |  | HTML iconHTML  

    The paper presents a simple model for the nonlinear magnetization characteristics of a switched reluctance motor (SRM). The flux linkage is given as a continuous mathematical expression, depending on the phase current and rotor position. This expression can then be differentiated or integrated easily without computer use; it enables finding a mathematical formula for the instantaneous torque of each phase. The model is valuable for computer-aided designs, especially for sizing and initial estimates, where accuracy can be traded with time saving. The model was implemented to verify its degree of accuracy. The simulation program has the ability to calculate numerous parameters that can be very useful for quick estimates of the efficiency for a particular SRM drive or even when choosing a particular motor. View full abstract»

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  • Theoretical analysis of control properties for the brushless doubly fed reluctance machine

    Page(s): 332 - 339
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (291 KB) |  | HTML iconHTML  

    The brushless doubly fed induction machine (BDFIM) has been extensively researched for approximately 30 years, but a related machine [the brushless doubly fed reluctance machine (BDFRM)], has not. This was mainly due to the fact that reluctance rotor designs were not capable of generating saliency ratios large enough to make the BDFRM competitive with other machines. However, recent developments in reluctance rotors, spurred on by research into synchronous reluctance machines, has resulted in high saliency ratio rotors that are economic to build. This, together with the promise of higher efficiency and simpler control compared to the BDFIM, means that further investigation of the BDFRM is warranted. A relatively limited amount of work to date has been published on the BDFRM. This paper attempts to fill this void by presenting a theoretical analysis of some of the important control properties of the ideal BDFRM. View full abstract»

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  • Brushless exciter modeling for small salient pole alternators using finite elements

    Page(s): 306 - 312
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB) |  | HTML iconHTML  

    In this paper, the self and mutual inductances of an exciter for a genset alternator are estimated for different rotor angular positions by the use of finite-element (FE) techniques. These inductances, which are described by complex functions, are measured using a stationary test and compared with calculated values. A real-time computer model for the exciter, the load and the diode bridge mounted on the rotor is then proposed, and a sample of performance prediction and measurement for a specific transient condition of the exciter is presented here as confirmation of the method. The model thus validated is ultimately to be included in the evolving total system model used for simulation of genset transient and steady-state performance. View full abstract»

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  • Improving voltage disturbance rejection for variable-speed wind turbines

    Page(s): 422 - 428
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (326 KB)  

    In this paper, the effect of voltage dips on variable-speed wind turbines using voltage source converters (VSCs) is treated. Three different current controllers for the VSC are described and implemented. Their performance is evaluated when the converter is subject to different types of voltage dips. Both simulated and measured dips are used. The effect of the phase-angle jump of the dips is also taken into account. View full abstract»

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  • A methodology for characterizing fault tolerant switched reluctance motors using neurogenetically derived models

    Page(s): 380 - 384
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (234 KB) |  | HTML iconHTML  

    This paper examines the feasibility of using artificial neural networks (ANNs) and genetic algorithms (GAs) to develop discrete time dynamic models for fault free and faulted switched-reluctance-motor (SRM) drive systems. The results of using the ANN-GA-based (neurogenetic) model to predict the performance characteristics of a prototype SRM drive motor under normal and abnormal operating conditions are presented and verified by comparison to test data. View full abstract»

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  • A new synthetic loading for large induction machines with no feedback into the power system

    Page(s): 319 - 324
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB) |  | HTML iconHTML  

    Full-load testing of large induction machines is constrained by the limitations in the power-supply and loading equipment of the manufacturer's facilities, resulting in costly set up time. A new synthetic loading method is proposed based on a bang-bang phase control strategy. The rated power oscillation created is routed to an auxiliary system and the source hydro has to provide only the total losses of the system, without seeing the excessive power swings observed in other synthetic loading techniques. In this technique, only induction machines are used which would enable motor manufacturers to build the test rig in-house. The control stage is very simple to implement and requires only unregulated DC supplies for the excitation windings. The method is suitable for any induction machine and does not requires any set up time. It is possible to strictly maintain constant DEFINE RMS voltage and current at rated values for the duration of the heat runs. View full abstract»

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  • Variable-speed wind power generation using doubly fed wound rotor induction machine-a comparison with alternative schemes

    Page(s): 414 - 421
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB)  

    In this paper, a wind energy conversion system (WECS) using a grid-connected wound rotor induction machine controlled from the rotor side is compared with both fixed speed and variable speed systems using a cage rotor induction machine. The comparison is done on, the basis of: (1) major hardware components required; (2) operating region; and (3) energy output due to a defined wind function using the characteristics of a practical wind turbine. Although a fixed speed system is more simple and reliable, it severely limits the energy output of a wind turbine. In case of variable speed systems, comparison shows that using a wound rotor induction machine of similar rating can significantly enhance energy capture. This comes about due to the ability to operate with rated torque even at supersynchronous speeds; power is then generated out of the rotor as well as the stator. Moreover, with rotor side control, the voltage rating of the power devices and DC bus capacitor bank is reduced. The size of the line side inductor also decreased. Results are presented to show the substantial advantages of the doubly fed system. View full abstract»

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  • Motional time-harmonic simulation of slotted single-phase induction machines

    Page(s): 313 - 318
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (290 KB) |  | HTML iconHTML  

    Considering motional effects in the steady-state finite-element simulation of single-phase induction machines inevitably requires a transient approach. The resulting computation time seriously hampers the application of finite elements within technical designs. In this paper, time-harmonic finite-element simulation, as commonly applied to the three-phase induction machine model, is also enabled for single-phase motors by decomposing the air-gap field in two revolving fields in the opposite direction. The advantages and drawbacks of the novel approach are illustrated by a benchmark model. Issues such as ferromagnetic saturation, external circuit coupling, adaptive mesh refinement, and torque computation are addressed. The method is used to simulate a capacitor start/run motor. View full abstract»

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  • On the use of singular perturbations to neglect the dynamic saliency of synchronous machines

    Page(s): 385 - 391
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (290 KB)  

    A common approximation used in the analysis of power systems is the neglect of the dynamic saliency in synchronous machines. In this paper, it is shown that eliminating the error associated with neglecting dynamic saliency can be accomplished with the addition of a singular perturbation(s) into the machine model. By considering the elimination of error in such a way, singular-perturbation-based model-order-reduction techniques are used to derive detailed- and reduced-order models of synchronous machines where dynamic saliency is eliminated with zero error and no added numerical cost. View full abstract»

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  • Induction generator controller based on the instantaneous reactive power theory

    Page(s): 368 - 373
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (221 KB)  

    A novel control strategy for a stand-alone induction generator (IG), working with variable speed and load, is proposed. The IG is simultaneously excited by a capacitor and an inverter. The capacitor provides the rated reactive current needed to excite the IG while the inverter adds the reactive current needed to regulate the IG output voltage. The control strategy is based on the instantaneous reactive power theory. A 4 kW laboratory prototype has been built to validate the proposal and experimental results are presented. View full abstract»

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  • Improved field oriented control of an LIM having joints in its secondary conductors

    Page(s): 349 - 355
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (341 KB)  

    This paper presents a primary-flux-control algorithm suitable for applications in short-primary long-secondary linear induction motor-drive systems. The advantage of the proposed control algorithm is that it is more robust than the conventional vector control algorithm to the variation of the secondary resistance caused by the effect of a joint in the secondary conductors, which can be made of several pieces of aluminum plates or rails joined together. The algorithm was tested by simulation on a sample of linear motor disk-drive system. The simulation results were compared to those obtained by a conventional vector control algorithm. Simulations and experiments have shown that the fluctuations of the thrust and attraction forces obtained with the proposed primary-flux control algorithm were significantly less than those obtained with the conventional vector control algorithm. View full abstract»

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  • Vector optimization design of a shaded-pole induction motor

    Page(s): 374 - 379
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (249 KB) |  | HTML iconHTML  

    The design problem of a shaded-pole induction motor is represented as a vector optimization problem. The problem is solved using a nonlinear programming technique. The motor is designed with different requirements. These requirements are represented by weighted elements of the objective function vector and a set of constraints. The objective functions are the goals of a design procedure where the designer tries to achieve their extreme (optimal) values. The adopted approach provides the flexibility for the designer to represent the importance of goals in "weights" and finds the optimal design according to these weights. Implementation of this approach is presented by designing a motor with two objective functions (starting torque and cost). The results obtained verify the ability of this approach to achieve valuable improvements. View full abstract»

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  • The available matching of solar arrays to DC motors having both constant and series-excited field components

    Page(s): 301 - 305
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (254 KB)  

    This paper presents a procedure for increasing the daily output mechanical energy supplied by DC motors directly connected to solar cell arrays (SCA). The technique is based on the use of DC motors with two components of magnetic field: a constant component that can be provided by a permanent magnet (or a separately excited winding) and a second one produced by a series field winding. It will be shown that through properly selecting the parameters of the motor's magnetic circuit, (i.e., the value of the constant field and the mutual inductance as well as their relative directions), an improved matching between the PV-array and the dc motor can be achieved. Based on assessing and minimizing an expression used to quantify the power mismatch between the SCA and the dc motor, the optimal parameters will be identified. A comparison will then be made between this suggested motor design and tooth the separately excited and series motors. View full abstract»

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  • Performance analysis of a three-phase induction motor under mixed eccentricity condition

    Page(s): 392 - 399
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    A substantial proportion of induction motor faults are eccentricity related. In practice, static and dynamic eccentricities happen to exist together. With this point in mind, an analytical approach to evaluate the performance of a three-phase induction motor under mixed eccentric conditions is presented in this paper. A clear and step-by-step theoretical analysis, explaining completely the presence of certain harmonics in the line-current spectrum in the presence of eccentricity, is discussed. More importantly, it is shown for the first time that a link exists between the low- and high-frequency elements of these harmonics. It is also shown that these high-frequency components are not very strong in all types of machine. These results will be useful in generating rules and laws to formulate online tools for machine condition monitoring. Finite-element results to substantiate the inductance values used in the simulation are also included. The analysis is validated by the line-current spectrum of the eccentric machine obtained through simulation using the modified winding-function approach (MWFA) and experimentation. View full abstract»

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  • Optimal design of power-system stabilizers using particle swarm optimization

    Page(s): 406 - 413
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (329 KB)  

    In this paper, a novel evolutionary algorithm-based approach to optimal design of multimachine power-system stabilizers (PSSs) is proposed. The proposed approach employs a particle-swarm-optimization (PSO) technique to search for optimal settings of PSS parameters. Two eigenvalue-based objective functions to enhance system damping of electromechanical modes are considered. The robustness of the proposed approach to the initial guess is demonstrated. The performance of the proposed PSO-based PSS (PSOPSS) under different disturbances, loading conditions, and system configurations is tested and examined for different multimachine power systems. Eigenvalue analysis and nonlinear simulation results show the effectiveness of the proposed PSOPSSs to damp out the local and interarea modes of oscillations and work effectively over a wide range of loading conditions and system configurations. In addition, the potential and superiority of the proposed approach over the conventional approaches is demonstrated. View full abstract»

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  • Magnetic saturation effects on the control of a synchronous reluctance machine

    Page(s): 356 - 362
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (355 KB)  

    Experimental results on the magnetic saturation effects on the control of a small synchronous reluctance machine (600 W) are presented in this paper. A new model of the machine, including saturation effects and cross magnetization is first developed. An approach based on total and mutual inductances is followed instead of the traditional approach through magnetizing and leakage inductances. All of the electrical and mechanical parameters measurements required for the simulations are given. A rotor-oriented vector control of the synchronous reluctance machine is achieved with a digital-signal-processor (DSP) board (TMS320C31) and experimental results are presented. When the magnetic circuit is saturated, the simulation with the developed model shows good, accurate results when compared to the experimental ones. View full abstract»

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  • Analysis, dimensional sizing and configuration comparison of switched-reluctance motors operating under multiphase excitation

    Page(s): 325 - 331
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (291 KB)  

    The paper presents a simple approach for analyzing switched reluctance motors (SRMs) operating under multiphase excitation. The analysis results in specific design coefficients [derived from the SRM flux and magnetomotive force (MMF) distributions that can be used in a methodology] to calculate the SRMs initial dimensions while taking into account the magnetic loading and electric loading. Finally, the approach enables comparison of SRM configurations for an application without performing complete designs. The magnetic loading (i.e., saturation) and torque of various SRM configurations designed using the proposed approach are verified through finite-element analysis (FEA). View full abstract»

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  • Characterization of coil faults in an axial flux variable reluctance PM motor

    Page(s): 340 - 348
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (337 KB)  

    Variable-reluctance (VR) and switch-reluctance (SR) motors have been proposed for use in applications requiring a degree of fault tolerance. A range of topologies, of brushless SR and VR permanent-magnet (PM) motors are not susceptible to some types of faults, such as phase-to-phase shorts, and can often continue to function in the presence of other faults. In particular, coil-winding faults in a single stator coil may have relatively little effect on motor performance but may affect overall motor reliability, availability, and longevity. It is important to distinguish between and characterize various winding faults for maintenance and diagnostic purposes. These fault characterization and analysis results are a necessary first step in the process of motor fault detection and diagnosis for this motor topology. This paper examines rotor velocity damping due to stator winding turn-to-turn short faults in a fault-tolerant axial flux VR PM motor. In this type of motor, turn-to-turn shorts, due to insulation failures, have similar I-V characteristics as coil faults resulting from other problems, such as faulty maintenance or damage due to impact. In order to investigate the effects of these coil faults, a prototype axial flux VR PM motor was constructed. The motor was equipped with experimental fault simulation stator windings capable of simulating these and other types of stator winding faults. This paper focuses on two common types of winding faults and their effects on rotor velocity in this type of motor. View full abstract»

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  • A complete lumped equivalent circuit of three-phase squirrel-cage induction motors using two-dimensional finite-elements technique

    Page(s): 363 - 367
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (310 KB) |  | HTML iconHTML  

    The paper presents the use of the finite element technique for determining the parameters of a three-phase squirrel-cage induction motor. The common parameters in addition to the core losses and ratio of number of turns are obtained from the finite-element field solutions. The magnetizing characteristic and core losses curve are used to determine the flux distribution within the motor structure. The linear time harmonic vector potential field solution is used for the inductances computation. The accuracy of the finite-element application is verified using the available precise results. View full abstract»

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Aims & Scope

The IEEE Transactions on Energy Conversion includes in its venue the research, development, design, application, construction, installation, operation, analysis and control of electric power generating and energy storage equipment (along with conventional, cogeneration, nuclear, distributed or renewable sources, central station and grid connection). The scope also includes electromechanical energy conversion, electric machinery, devices, systems and facilities for the safe, reliable, and economic generation and utilization of electrical energy for general industrial, commercial, public, and domestic consumption of electrical energy.

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Meet Our Editors

Editor-in-Chief
Juri Jatskevich
University of British Columbia