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Energy Conversion, IEEE Transactions on

Issue 4 • Date Dec. 2004

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Displaying Results 1 - 25 of 27
  • Table of contents

    Page(s): c1 - c4
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  • IEEE Transactions on Energy Conversion publication information

    Page(s): c2
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  • Influence of unbalanced voltage on the steady-state performance of a three-phase squirrel-cage induction motor

    Page(s): 657 - 662
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (432 KB) |  | HTML iconHTML  

    The negative effects of a particular unbalanced voltage on the performance of an induction motor are studied in this paper. The paper suggests that the available definitions of unbalanced voltages are not comprehensive and complete. Therefore, the results of these analyses on motor performance are not very reliable. To prove this claim, a three-phase 25-hp squirrel-cage induction motor is analyzed under different unbalanced conditions. It is shown that it is necessary to define a more precise unbalanced factor for more accurate results. Experimental results verify the theoretical analysis. View full abstract»

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  • Radial basis function identifier and pole-shifting controller for power system stabilizer application

    Page(s): 663 - 670
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    Use of a mixed structure consisting of a radial basis function (RBF) network and pole-shifting feedback controller for power system stabilizer application is presented in this paper. The RBF network is used to identify the time-varying parameters of the power system. The RBF has a simple structure with a nonlinear hidden layer which constructs local approximations to nonlinear input-output mapping and a linear output layer. The network is capable of fast learning and represents a nonlinear autoregressive moving average model with exogeneous inputs (NARMAX). The NARMAX model is transformed into a linear ARMA model every sampling period and the pole-shift controller is used to calculate the control signal. This process of linearizing a nonlinear system is important because of the widespread industrial acceptance of linear feedback controllers, availability of theoretical and practical results about robustness, and closed-loop stability. Simulation studies carried out on a single-machine infinite bus power system verify the effectiveness of the above approach. View full abstract»

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  • Design and testing of a four-phase fault-tolerant permanent-magnet machine for an engine fuel pump

    Page(s): 671 - 678
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    This paper discusses the design and testing of an aircraft electric fuel pump drive. The drive is a modular, four-phase, fault-tolerant system which is designed to meet the specification with a fault in any one of the phases. The motor employed has a permanent-magnet rotor with the magnets arranged in a Halbach array to maximize the air-gap flux density. Exceptionally high electric loadings are obtained by flooding the entire motor with aircraft fuel, which acts as an excellent cooling agent. Theoretical results are compared with test results gained in conditions approaching those found in an aircraft. Tests are carried out on the unfaulted drive and with one of several fault scenarios imposed. The electrical and thermal performance of the drive is assessed, showing how the flooded fuel cooling has excellent performance without introducing significant drag on the rotor. View full abstract»

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  • Preliminary performance evaluation of switched reluctance motors with segmental rotors

    Page(s): 679 - 686
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    This paper examines the performance of switched reluctance machines which employ a segmental rotor construction in preference to the usual toothed structure. Two three-phase designs are considered, one in which the windings span a number of teeth and one in which they span a single tooth. Two demonstrators have been built-one for each design type, and their performances are compared with both conventional switched reluctance motors (SRMs) and a rare earth permanent-magnet machine. It is shown how these machines can operate from a standard SRM converter: running test results are presented and there is a discussion of general operating experience, ranging from the measurement of mean torque, voltage, and current-controlled operation to general thermal performance. View full abstract»

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  • A standstill frequency response method for large salient pole synchronous machines

    Page(s): 687 - 691
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    In this article, a Standstill Frequency Response Test (SSFR) is proposed, with the aim of determining the direct and quadrature axis operational impedances for salient pole synchronous machines. The method is applied with the rotor at standstill in a given arbitrary position, thus avoiding the difficulties in rotor mechanical alignment and rendering it suitable for large salient pole synchronous machines of hydroelectric power plants. View full abstract»

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  • Influence of the variable-speed wind generators in transient stability margin of the conventional generators integrated in electrical grids

    Page(s): 692 - 701
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    This work demonstrates that the integration of variable-speed wind systems with doubly fed induction generators (DFIG) and a four-quadrant AC-to-AC converter connected to the rotor windings increases the transient stability margin of the electrical grids, when compared with the case where the fixed speed wind systems with cage generators are used. It is due to the influence of the two dedicated rotor current regulators of the DFIG on the dynamic behavior of the other generators in the system. Besides, adequate models to represent the behavior of the DFIG in transient stability studies are presented. From the simulation results, some important conclusions can be extracted to guide the integration of the wind farms on weak or strong grids. View full abstract»

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  • Multi-stress aging of stator bars with electrical, thermal, and mechanical stresses as simultaneous acceleration factors

    Page(s): 702 - 714
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    Accelerated aging tests have been carried on stator bars under simultaneous electrical, thermal and mechanical multi-stress conditions, using a simulated three-phase model stator. Over each thermal load cycle, the partial discharge activity has been found to be a strong function of temperature. Tests at twice rated electrical stress did not result in any bar specimen failures up to a total of 1500 load cycles. However, when the three phase load current was increased above its rated value, current-limited type failures were observed to occur below 1000 load cycles, thereby indicating a marked influence of thermal and mechanical stresses associated with the elevated three phase load current. View full abstract»

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  • Optimal efficiency control strategy for interior permanent-magnet synchronous motor drives

    Page(s): 715 - 723
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB) |  | HTML iconHTML  

    In this paper, the problem of efficiency optimization in vector-controlled interior permanent-magnet (PM) synchronous motor drives is investigated. A loss model controller is introduced that determines the optimal d-axis component of the stator current that minimizes power losses. For the implementation of the suggested controller, the knowledge of the loss model is not required since an experimental procedure is followed to determine its parameters. Furthermore, it is shown that the loss model of the interior PM motor can be used as a basis for deriving loss minimization conditions for surface PM synchronous motors and synchronous reluctance motors as well. Experimental results of an interior PM motor are presented to validate the effectiveness of the proposed method and demonstrate the operational improvements. View full abstract»

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  • Voltage regulation optimization of compensated self-excited induction generator with dynamic load

    Page(s): 724 - 732
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    The configuration of short-shunt self-excited induction generator feeding induction motor loads (SEIG-IM) suffers from excessive transients during startup of motor load under no load and unstable operation. These problems may be due to subsynchronous resonance as obtained with series compensated transmission line or due to the connected load system. The use of damping resistors across series capacitors is proposed to damp out the starting transients and for the stable operation. The steady-state model of short shunt SEIG-IM with damping resistors and resistive and motor load is developed to obtain the values of shunt and series capacitances for optimum voltage regulation. The simulated annealing like approach is used to solve voltage regulation optimization problem. The values of shunt and series capacitances and damping resistance are obtained for optimum voltage regulation under entire loading range and stable operation during starting and loading. The results are experimentally verified, which establish the effectiveness of damping resistance and developed algorithm. View full abstract»

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  • Nonlinear identification of a brushless excitation system via field tests

    Page(s): 733 - 740
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB) |  | HTML iconHTML  

    In this paper, nonlinear identification of the excitation system (EXS) in the gas unit #2 of Rajaee power plant in Iran is presented. Two methods of modeling, i.e., grey-box and black-box modeling are used and compared. In the grey-box (classical) approach, first a block-diagram for the EXS is suggested, then a test procedure for identification of its parameters is outlined. The input-output data corresponding to each block of the system is obtained through field tests. In this approach, the only nonlinearities considered in the block diagram are the limits. The other nonlinearities are reflected in the change of parameters in the linear transfer functions at different operating conditions. In the black-box approach, identification of the system is carried out using discrete wavelet transform. A variable structure wavelet was tried to cope with system changes at different operating conditions, but a wavelet with fixed number of scaling functions or wavelet functions proved to be quite adequate. The simulation results and their comparison, show the good accuracy of both derived models. Although the model obtained through the black-box approach shows a better fit when its output is compared with the measured variables, the model obtained through the grey-box approach reflects the physical properties of the system and may be more useful for power engineers. View full abstract»

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  • Biobjective power dispatch using goal-attainment method and adaptive polynomial networks

    Page(s): 741 - 747
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB) |  | HTML iconHTML  

    This paper presents an integrated approach that combines goal-attainment (GA) and adaptive polynomial networks (APN) to real-time biobjective power dispatch. The goals considered are fuel cost and the environmental impact of multiple emissions. The complicated relationships between the input (power demand and operator's economic and emission preferences) and the output (power generated by each generator) can be efficiently modeled by the APN. Moreover, the APN can rapidly provide an accurate estimate of the real-time dispatch results for the power demand and the operator's preferences. The effectiveness of the proposed approach has been demonstrated by the IEEE 30-bus six-generator and the practical Taipower 388-bus 27-generator systems. Test results reveal that the proposed approach achieves significant savings in computation time and reduces the complexity of the real-time power dispatch. Furthermore, the proposed APN outperforms the artificial neural networks (ANNs) method, in both developing the model and estimating the power generated by each generator. View full abstract»

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  • A model of PV generation suitable for stability analysis

    Page(s): 748 - 755
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (704 KB) |  | HTML iconHTML  

    This paper describes a model of photovoltaic (PV) generation suitable for studying its interactions with the power system. Experimental results suggest that the maximum power point tracking part of the control system of the PV generator dominates the dynamic behavior of the system. These experimental results are used to develop and validate the proposed model. It is shown that the model accurately reflects the behavior of the generator following both small and fast changes in irradiance and AC grid voltage. The proposed model is designed to be integrated in a dynamic simulation program. View full abstract»

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  • Dynamical variable structure controller for power regulation of wind energy conversion systems

    Page(s): 756 - 763
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB) |  | HTML iconHTML  

    The paper addresses the problem of output power regulation of fixed-pitch variable-speed wind energy conversion systems. Operation is constrained by practical reasons to the low-speed side of the turbine power-speed curve. Unfortunately, this region is characterized by a nonminimum phase dynamics which is an obstacle to perform the regulation task. A dynamical variable structure controller is developed that accomplishes the control objective despite this limitation. The proposed control strategy presents attractive features such as robustness to parametric uncertainties of the turbine and generator as well as to electric grid disturbances. View full abstract»

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  • An approach to quantify the technical benefits of distributed generation

    Page(s): 764 - 773
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    Recent changes in the electric utility infrastructure have created opportunities for many technological innovations, including the employment of distributed generation (DG) to achieve a variety of benefits. After a brief discussion of the benefits, this paper proposes a general approach and a set of indices to assess some of the technical benefits in a quantitative manner. The indices proposed are: 1) voltage profile improvement index; 2) line-loss reduction index; 3) environmental impact reduction index; and 4) DG benefit index. Simulation results obtained using a simple 12-bus test system and a radial system are presented and discussed to illustrate the value and usefulness of the proposed approach. View full abstract»

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  • Experimental evaluation of nonlinear robust control for SMES to improve the transient stability of power systems

    Page(s): 774 - 782
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB) |  | HTML iconHTML  

    This paper presents a new approach and corresponding experiments for the nonlinear robust control of a superconducting magnetic energy storage (SMES) unit to improve the transient stability of power systems. Based on the result of SMES prototype experience, a new dynamic model with disturbances of SMES is adopted, and transferred to the per unit system for simplifying the dynamic analysis and controller design. Then, feedback linearization scheme and linear H control theory are applied to design a novel SMES nonlinear robust controller in a one-machine infinite bus (OMIB) power system. In order to confirm such positive effects of the proposed control strategy, experiments are carried on a laboratory setup of SMES comparing that with a conventional proportional-integral (PI) controller. The results of the experiments demonstrate that the proposed nonlinear robust controller has more excellent performance to improve the transient stability of power systems than that of conventional PI controllers. View full abstract»

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  • Analysis and design of STATCOM-based voltage regulator for self-excited induction generators

    Page(s): 783 - 790
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB) |  | HTML iconHTML  

    This paper deals with the design of static compensator (STATCOM)-based voltage regulator for self-excited induction generators (SEIGs). SEIG has poor voltage regulation and it requires adjustable reactive power source with varying load to maintain constant terminal voltage. The required reactive power can be provided by a STATCOM consisting of ac inductors, a dc bus capacitor, and solid-state self-commutating devices. Selection and ratings of these components are quite important for design and control of STATCOM to regulate the terminal voltage of SEIG. The analysis, design, and selection of these STATCOM components are presented for five different rating machines to operate at varying power factor loads. Two criteria (full and reduced rating of STATCOM) are considered while designing STATCOM-SEIG systems. View full abstract»

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  • Lumped-parameter thermal model for induction machines

    Page(s): 791 - 792
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (128 KB) |  | HTML iconHTML  

    A novel lumped-parameter thermal model for induction machines that can be included in real-time applications is presented. The model considers just stator, rotor, and environment representative temperatures so that parameter estimation can be carried out. Thermal parameters are experimentally obtained and a sensorless vector control application with a 1-kW induction motor is included showing the effectiveness of the proposed solution. View full abstract»

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  • A simple model-based online rotor time constant estimator for an induction machine

    Page(s): 793 - 794
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (95 KB) |  | HTML iconHTML  

    A new model-based online rotor time constant estimator for an induction machine is developed. The estimation algorithm is based on induction machine models in two different reference frames. Novel mechanism is proposed to avoid the singularity problem. Encouraging simulation results are given to demonstrate the effectiveness of the simple yet accurate estimator. View full abstract»

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  • ANFIS-based diagnosis and location of stator interturn faults in PM brushless DC motors

    Page(s): 795 - 796
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB) |  | HTML iconHTML  

    An automatic scheme for fault diagnosis and location of stator-winding interturns in permanent-magnet brushless dc motors is presented. System performances under healthy and faulty operation are obtained via a discrete-time model. Waveform of the electromagnetic torque is monitored and processed using discrete Fourier transform and short-time Fourier transform to derive proper diagnostic indices. Two adaptive neuro-fuzzy inference systems (ANFIS) are developed to automate the fault diagnosis process. Test results show an acceptable performance for ANFIS in detecting the fault. View full abstract»

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  • Experimental setup for the measurement of surge propagation in induction machines

    Page(s): 797 - 799
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    This paper presents the experimental setup for the measurement of surges and their propagation within the turns of a coil in an induction machine. Recent advances in data capture techniques makes this work possible, which will lead to an improved understanding of the mechanisms involved. View full abstract»

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  • Comparison of the response of doubly fed and fixed-speed induction generator wind turbines to changes in network frequency

    Page(s): 800 - 802
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB) |  | HTML iconHTML  

    Synchronous and fixed-speed induction generators release the kinetic energy of their rotating mass when the power system frequency is reduced. In the case of doubly fed induction generator (DFIG)-based wind turbines, their control system operates to apply a restraining torque to the rotor according to a predetermined curve with respect to the rotor speed. This control system is not based on the power system frequency and there is negligible contribution to the inertia of the power system. A DFIG control system was modified to introduce inertia response to the DFIG wind turbine. Simulations were used to show that with the proposed control system, the DFIG wind turbine can supply considerably greater kinetic energy than a fixed-speed wind turbine. View full abstract»

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  • 2004 Index

    Page(s): 803 - 818
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    Freely Available from IEEE
  • Need to know? Visit the PES web site [advertisement]

    Page(s): 819
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    Freely Available from IEEE

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.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Juri Jatskevich
University of British Columbia