Scheduled System Maintenance on December 17th, 2014:
IEEE Xplore will be upgraded between 2:00 and 5:00 PM EST (18:00 - 21:00) UTC. During this time there may be intermittent impact on performance. We apologize for any inconvenience.
By Topic

Energy Conversion, IEEE Transactions on

Issue 2 • Date June 2009

Filter Results

Displaying Results 1 - 25 of 34
  • Table of contents

    Page(s): C1 - C4
    Save to Project icon | Request Permissions | PDF file iconPDF (127 KB)  
    Freely Available from IEEE
  • IEEE Transactions on Energy Conversion publication information

    Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (39 KB)  
    Freely Available from IEEE
  • Piezoelectric Actuator Design and Placement for Switched Reluctance Motors Active Damping

    Page(s): 305 - 313
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (739 KB) |  | HTML iconHTML  

    This paper describes the design and the placement of piezoelectric actuators on switched reluctance motors by means of a genetic algorithm (nondominated sorting genetic algorithm II) for the purpose of reducing stator vibrations. Two distinct approaches are presented: one energy-related and the other based on a minimization of the resultant displacement. These methods lead to design and placement strategy for the piezoelectric actuators. A number of optimal actuators obtained using these kinds of approaches is also compared with mechanical finite-element simulations. At last, a solution is achieved in order to validate optimal placement using positive position feedback active filtering. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • “Active Flux” DTFC-SVM Sensorless Control of IPMSM

    Page(s): 314 - 322
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (695 KB) |  | HTML iconHTML  

    This paper proposes an implementation of a motion-sensorless control system in wide speed range based on "active flux" observer, and direct torque and flux control with space vector modulation (DTFC-SVM) for the interior permanent magnet synchronous motor (IPMSM), without signal injection. The concept of "active flux" (or "torque producing flux") turns all the rotor salient-pole ac machines into fully nonsalient-pole ones. A new function for Lq inductance depending on torque is introduced to model the magnetic saturation. Notable simplification in the rotor position and speed estimation is obtained, because the active flux position is identical with the rotor position. Extensive experimental results are presented to verify the principles and to demonstrate the effectiveness of the proposed sensorless control system. With the active flux observer, the IPMSM drive system operates from very low speed of 2 r/min at half full-load up to 1400 r/min. Higher speed is possible, in principle, with flux weakening. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Impact of MMF Space Harmonic on Rotor Losses in Fractional-Slot Permanent-Magnet Machines

    Page(s): 323 - 328
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (481 KB) |  | HTML iconHTML  

    The fractional-slot permanent-magnet (PM) machines are used in many applications due to their high torque density, low torque ripple, and high efficiency. However, the fractional-slot machines are characterized by high contents of space harmonics in the air-gap MMF distribution. Such harmonics cause flux variation in the air gap, and the main consequence is the induced losses in the rotor. Depending on the combination of slots and poles of the machine, there are different harmonic contents and then rotor losses. By means of a simple model of the rotor losses, this paper investigates the link between the rotor losses and the combination of the slots and the poles of the fractional-slot PM machines. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Synchronous Generator Output Voltage Real-Time Feedback Control via H_\infty Strategy

    Page(s): 329 - 337
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (619 KB) |  | HTML iconHTML  

    A new approach on synchronous generator (SG) output voltage control is presented. The originality of such a strategy is based on the excitation structure that integrates a permanent-magnet generator combined with a modern control method: the H infin. The main motivation of this paper is the debatable results obtained with the classical excitation structure controlled by a traditional PID controller. The SG model as well as the control strategy will be presented. The implementation in real time domain and a comparison with the classical structure will allow us to prove the efficiency of the proposed structure compared to the classical one as regards the reference tracking and signal quality. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Population-Based Design of Surface-Mounted Permanent-Magnet Synchronous Machines

    Page(s): 338 - 346
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB) |  | HTML iconHTML  

    Permanent-magnet synchronous machines can be designed to obtain high efficiency and high torque density. Population-based optimization methods such as genetic algorithms and particle swarm optimization are gaining acceptance as a means of optimizing the design of this class of machines. This paper builds on the literature by utilizing a computationally efficient machine analysis appropriate for use with population-based optimization methods that enables the consideration of a significantly larger search space than previously reported in the literature. It is also unique in that the relative performance of different parameter encoding and objective function formulations are considered. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analytical Design Model for Surface-Mounted Permanent-Magnet Synchronous Machines

    Page(s): 347 - 357
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (498 KB) |  | HTML iconHTML  

    Design of electric machinery using population-based optimization requires a highly computationally efficient means of predicting the field distribution as well as the lumped-circuit model parameters. This paper proposes and validates a relatively straightforward analysis appropriate to this end. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Novel Method of Evaluating Performance Characteristics of a Self-Excited Induction Generator

    Page(s): 358 - 365
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (419 KB) |  | HTML iconHTML  

    Self-excited induction generators (SEIG) are increasingly being used in isolated areas to generate electrical energy from both conventional and nonconventional energy sources. This paper proposes a novel method of evaluating the steady-state performance characteristics of a SEIG under various operating conditions. The criteria for the constant terminal voltage and the constant-stator-current operations are also derived and embedded into the system of equations. Unlike the previous methods of analysis, the problem is formulated in a simple and straightforward way without going through lengthy and tedious derivation for the coefficients of a set of nonlinear equations. The formulated problem is then solved using a numerical-based routine ldquofsolverdquo given in MATLAB. The effectiveness of the proposed method is then evaluated on a 220-V, 1.5-kW induction generator for various operating conditions. Some of the simulation results obtained by the proposed method are also compared with the corresponding experimental values and are found to be in very good agreement. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Field Reconstruction Technique for Efficient Modeling of the Fields and Forces Within Induction Machines

    Page(s): 366 - 374
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (595 KB) |  | HTML iconHTML  

    Traditional analysis and design of induction machines have been largely based upon lumped-parameter models. An alternative tool used for field-based evaluations of an induction machine is the finite-element method. Although useful, its computational complexity limits its use as a design tool. In this paper, a field reconstruction (FR) method for induction machine simulation is introduced. The FR method utilizes a small number of finite-element evaluations to establish basis functions of normal and tangential flux densities. The basis functions are then used to estimate the magnetic field under arbitrary stator excitation. Using such a tool, evaluation of fields and forces produced by a machine under alternative excitation strategies can be explored efficiently. Moreover, alternative field-based derivation of stator/rotor excitation control can be explored. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Real-Time Speed and Flux Adaptive Control of Induction Motors Using Unknown Time-Varying Rotor Resistance and Load Torque

    Page(s): 375 - 387
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (458 KB) |  | HTML iconHTML  

    In this paper, an algorithm for direct speed and flux adaptive control of induction motors using unknown time-varying rotor resistance and load torque is described and validated with experimental results. This method is based on the variable structure theories and is potentially useful for adjusting online the induction motor controller unknown parameters (load torque and rotor resistance). The presented nonlinear compensator provides voltage inputs on the basis of rotor speed and stator current measurements, and generates estimates for both the unknown parameters and the nonmeasurable state variables (rotor flux and derivatives of the stator current and voltage) that converge to the corresponding true values. Experiments show that the proposed method achieved very good tracking performance within a wide range of the operation of the induction motor with online variation of the rotor resistance: up to (87%). This high tracking performance of the rotor resistance variation demonstrates that the proposed adaptive control is beneficial for motor efficiency. The proposed algorithm also presented high decoupling performance and very interesting robustness properties with respect to the variation of the stator resistance (up to 100%), measurement noise, modeling errors, discretization effects, and parameter uncertainties (e.g., inaccuracies on motor inductance values). The other interesting feature of the proposed method is that it is simple and easily implementable in real time. Comparative results have shown that the proposed adaptive control decouples speed and flux tracking while standard field-oriented control does not. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Comparison of Nodal- and Mesh-Based Magnetic Equivalent Circuit Models

    Page(s): 388 - 396
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (339 KB) |  | HTML iconHTML  

    The magnetic equivalent circuit (MEC) technique is a powerful analysis and design tool that combines relative accuracy with moderate computational effort. In this paper, a nodal-based MEC formulation and a mesh-based MEC formulation of a magnetic system are compared. The Newton-Raphson algorithm is used to solve the algebraic system, and to draw conclusions about the computational efficiency of the two formulations under linear and nonlinear operation. Although the two formulations exhibit similar performance under linear operating conditions, the performance of the mesh-based model is significantly better than that of the nodal-based model under nonlinear operation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • 3-D Magnetic Equivalent Circuit Framework for Modeling Electromechanical Devices

    Page(s): 397 - 405
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (633 KB) |  | HTML iconHTML  

    Magnetic equivalent circuits (MECs) are becoming an accepted alternative to electrical-equivalent lumped-parameter models and finite-element analysis (FEA) for simulating electromechanical devices. Their key advantages are moderate computational effort, reasonable accuracy, and flexibility in model size. MECs are easily extended into three dimensions. But despite the successful use of MEC as a modeling tool, a generalized 3-D formulation useable for a comprehensive computer-aided design tool has not yet emerged (unlike FEA, where general modeling tools are readily available). This paper discusses the framework of a 3-D MEC modeling approach, and presents the implementation of a variable-sized reluctance network distribution based on 3-D elements. Force calculation and modeling of moving objects are considered. Two experimental case studies, a soft-ferrite inductor and an induction machine, show promising results when compared to measurements and simulations of lumped parameter and FEA models. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multivariable Self-Tuning Control of a Turbine Generator System

    Page(s): 406 - 414
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (243 KB) |  | HTML iconHTML  

    Results from a collaborative research and development program devoted to turbine generator (TG) control are described. Digital self-tuning excitation controllers were designed for a generator during the initial phase of the project, with the design subsequently extended to cover multivariable control of the TG, which is the topic of this paper. Simulations and tests on a laboratory-scale machine have been accomplished successfully and a prototype multivariable self-tuning controller has been built. A set of typical results is given, covering responses to fault conditions of the power system. The multivariable self-tuning controller is shown to have good potential for commercial use for the TG. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Control of DFIG-Based Wind Generation to Improve Interarea Oscillation Damping

    Page(s): 415 - 422
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (849 KB) |  | HTML iconHTML  

    Power systems with high penetration of wind power usually require long-distance transmission to export wind power to the market. Interarea oscillation is an issue faced in long-distance transmission. Can wind generation based on doubly fed induction generator (DFIG) help to damp oscillations and how? In this paper, a control scheme is developed for the DFIG with rotor-side converter to damp interarea oscillations. The DFIG is modeled in MATLABreg/Simulink utilizing its vector control scheme feature, and inner current control and outer active/reactive power control loops are modeled and designed. A two-area system that suffers from poor interarea oscillation damping along with a wind farm in the area that exports power is investigated. A damping controller is designed and time-domain simulations are used to demonstrate the effectiveness of the controller. The major contributions of the paper are as follows: 1) built a wind farm interarea oscillation study system based on the classical two-area four-machine system, 2) established that in vector control scheme, active power modulation can best help to damp oscillations, 3) successfully designed a feedback controller using remote signals with good interarea oscillation observability. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Step-Response Model Development for Dynamic Matrix Control of a Drum-Type Boiler–Turbine System

    Page(s): 423 - 430
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (282 KB) |  | HTML iconHTML  

    This paper presents the application of dynamic matrix control (DMC) to a drum-type boiler-turbine system. Two types of step-response models for DMC are investigated in designing the DMC; one is developed with the linearization of the nonlinear plant model and the other is developed with the process step-response data. Then, the control performances of the DMC based on both types of models are evaluated. Because of severe nonlinearity of drum water-level dynamics, it is observed that the simulation with the step-response model based on the test data shows satisfactory results, while the linearized model is not suitable for controller design of the drum-type boiler-turbine system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fault Detection and Diagnosis in a Set “Inverter–Induction Machine” Through Multidimensional Membership Function and Pattern Recognition

    Page(s): 431 - 441
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (980 KB) |  | HTML iconHTML  

    Nowadays, electrical drives generally associate inverter and induction machine. Thus, these two elements must be taken into account in order to provide a relevant diagnosis of these electrical systems. In this context, the paper presents a diagnosis method based on a multidimensional function and pattern recognition (PR). Traditional formalism of the PR method has been extended with some improvements such as the automatic choice of the feature space dimension or a ldquononexclusiverdquo decision rule based on the k-nearest neighbors. Thus, we introduce a new membership function, which takes into account the number of nearest neighbors as well as the distance from these neighbors with the sample to be classified. This approach is illustrated on a 5.5 kW inverter-fed asynchronous motor, in order to detect supply and motor faults. In this application, diagnostic features are only extracted from electrical measurements. Experimental results prove the efficiency of our diagnosis method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Harnessing High-Altitude Solar Power

    Page(s): 442 - 451
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (678 KB) |  | HTML iconHTML  

    As an intermediate solution between Glaser's satellite solar power (SSP) and ground-based photovoltaic (PV) panels, this paper examines the collection of solar energy using a high-altitude aerostatic platform. A procedure to calculate the irradiance in the medium/high troposphere, based on experimental data, is described. The results show that here a PV system could collect about four to six times the energy collected by a typical U.K.-based ground installation, and between one-third and half of the total energy the same system would collect if supported by a geostationary satellite (SSP). The concept of the aerostat for solar power generation is then briefly described together with the equations that link its main engineering parameters/variables. A preliminary sizing of a facility stationed at 6 km altitude and its costing, based on realistic values of the input engineering parameters, is then presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Experimental Study and Nonlinear Modeling of Discharge I–V Behavior of Valve-Regulated Lead–Acid Batteries

    Page(s): 452 - 458
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (545 KB) |  | HTML iconHTML  

    Valve-regulated lead-acid battery continues to be studied in some cost-sensitive applications, such as microhybrid electric vehicle and scooters. A dynamic battery I -V model is needed for system design, simulation, and real-time control purposes. Battery discharging behavior is one of the most important parts of the model. By reviewing previous studies, the authors find that there is a contradiction between the linear and nonlinear I-V behaviors, and this serves as a motivation for the current experimental study. Through regression analysis of experimental data, the nonlinear behavior is verified and a nonlinear dynamic Thevenin model is developed. The model is validated by voltage response tests with multistep current profiles as model input. The calculated voltage response results from the model fit the test results well. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Estimation of Energy Yield From Wind Farms Using Artificial Neural Networks

    Page(s): 459 - 464
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB) |  | HTML iconHTML  

    This paper uses the data from seven wind farms at Muppandal, Tamil Nadu, India, collected for three years from April 2002 to March 2005 for the estimation of energy yield from wind farms. The model is developed with the help of neural network methodology, and it involves three input variables-wind speed, relative humidity, and generation hours-and one output variable, which give the energy output from wind farms. The modeling is done using MATLAB software. The most appropriate neural network configuration after trial and error is found to be 3-5-1 (3 input layer neurons, 5 hidden layer neurons, 1 output layer neuron). The mean square error for the estimated values with respect to the measured data is 7.6times10-3. The results demonstrate that this work is an efficient energy yield estimation tool for wind farms. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ramp-Rate Control of Photovoltaic Generator With Electric Double-Layer Capacitor

    Page(s): 465 - 473
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (259 KB) |  | HTML iconHTML  

    This paper describes ramp rate control of a photovoltaic (PV) generator with an electric double-layer capacitor. The capacitor absorbs rapid fluctuations of PV generation, and allows the generator to change its output at a limited ramp rate. The output is mainly determined by a moving average of the PV generation, but the capacitor voltage is also counted to keep the voltage at a specified value, and accordingly, to make the capacitor small. An expression for the capacitor size is derived. The feedback gain of the capacitor voltage is also examined to maintain enough energy storage in the capacitor. Some experiments are executed to demonstrate and validate the proposed method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Forecasting the Wind Generation Using a Two-Stage Network Based on Meteorological Information

    Page(s): 474 - 482
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1032 KB) |  | HTML iconHTML  

    This paper proposes a practical and effective model for the generation forecasting of a wind farm with an emphasis on its scheduling and trading in a wholesale electricity market. A novel forecasting model is developed based on indepth investigations of meteorological information. This model adopts a two-stage hybrid network with Bayesian clustering by dynamics and support vector regression. The proposed structure is robust with different input data types and can deal with the nonstationarity of wind speed and generation series well. Once the network is trained, we can straightforward predict the 48-h ahead wind power generation. To demonstrate the effectiveness, the model is applied and tested on a 74-MW wind farm located in the southwest Oklahoma of the United States. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • PWM Energy Converters: Fractal Method of Dynamics Forecasting in Practical Application

    Page(s): 483 - 492
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (923 KB) |  | HTML iconHTML  

    A fractal method of dynamics forecasting is investigated from the viewpoint of practical application regarding pulsewidth modulation (PWM) energy converters (PECs). The method realizes the idea of PEC state estimation relative to the preliminary formed domains of periodic processes. With this purpose, a special space ldquois designedrdquo into which the periodic process domains are mapped from the parametrical space and transient phase trajectories-from the phase space. Mapping is provided with use of geometrical interpretation of fractal regularities that exist in the structures of both periodic process and transient phase trajectories. Computational and experimental investigations of the fractal method efficiency are carried out within the bounds of the scenario of dynamics evolution toward chaos through period doubling. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Coordinated Reactive Power Control of a Large Wind Farm and a STATCOM Using Heuristic Dynamic Programming

    Page(s): 493 - 503
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1023 KB) |  | HTML iconHTML  

    A novel interface neurocontroller (INC) is proposed for the coordinated reactive power control between a large wind farm equipped with doubly fed induction generators (DFIGs) and a static synchronous compensator (STATCOM). The heuristic dynamic programming (HDP) technique and radial basis function neural networks (RBFNNs) are used to design this INC. It effectively reduces the level of voltage sags as well as the over-currents in the DFIG rotor circuit during grid faults, and therefore, significantly enhances the fault ride-through capability of the wind farm. The INC also acts as a coordinated external damping controller for the wind farm and the STATCOM, and therefore, improves power oscillation damping of the system after grid faults. Simulation studies are carried out in PSCAD/EMTDC and the results are presented to verify the proposed INC. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Novel Scheme to Connect Wind Turbines to the Power Grid

    Page(s): 504 - 510
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB) |  | HTML iconHTML  

    In this paper, a new scheme is proposed to connect wind turbines to the power grid. This scheme helps in limiting the fault currents as well as in voltage unbalance compensation. Voltage is injected in series with the transmission line to limit the fault currents as well as to balance the voltages. This scheme allows wind turbines to remain synchronized to the grid during faults or during low voltages and is useful for doubly fed as well as squirrel cage induction generators. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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