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Energy Conversion, IEEE Transactions on

Issue 2 • Date June 2003

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Displaying Results 1 - 24 of 24
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  • A new energy recovery double winding cage-rotor induction machine

    Page(s): 315 - 320
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (373 KB) |  | HTML iconHTML  

    This paper proposes a new double winding induction machine and its speed control methods. The machine consists of two stator windings and one cage rotor. One stator acts as a motor and the other as a generator. By controlling the voltage supplied to the secondary or the generator winding, the rotor speed can be adjusted. The machine has a similar speed control characteristic to that of a slip-ring induction motor equipped with the rotor energy recovery scheme. The construction, principle, equivalent circuit, and speed control schemes of the new machine are presented. The performance characteristics of the machine are analyzed using the equivalent circuit and verified by experimental results. View full abstract»

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  • Neural network-based modeling and parameter identification of switched reluctance motors

    Page(s): 284 - 290
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (709 KB) |  | HTML iconHTML  

    Phase windings of switched reluctance machines are modeled by a nonlinear inductance and a resistance that can be estimated from standstill test data. During online operation, the model structures and parameters of SRMs may differ from the standstill ones because of saturation and losses, especially at high current. To model this effect, a damper winding is added into the model structure. This paper proposes an application of artificial neural network to identify the nonlinear model of SRMs from operating data. A two-layer recurrent neural network has been adopted here to estimate the damper currents from phase voltage, phase current, rotor position, and rotor speed. Then, the damper parameters can be identified using maximum likelihood estimation techniques. Finally, the new model and parameters are validated from operating data. View full abstract»

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  • Finite element analysis of a single-phase grid-connected induction generator with the Steinmetz connection

    Page(s): 321 - 329
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (519 KB) |  | HTML iconHTML  

    The Steinmetz connection enables a three-phase induction generator (IG) to operate satisfactorily on a single-phase grid by using only a capacitance phase converter. This paper presents a finite element analysis of this mode of IG operation. A time-stepping, two-dimensional (2-D) finite element method (FEM) is employed in the solver, with the external circuit equations coupled to the set of simultaneous equations formulated with the nodal magnetic vector potentials as the variables. A detailed rotor circuit model that accounts for the current density distribution as well as the end-ring parameters is also presented. Generator performance computed using FEM is compared with that computed using the method of symmetrical components and that obtained experimentally on a small induction machine. The results indicate that FEM gives an accurate prediction of the line current and the output power of the IG. View full abstract»

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  • IPM synchronous machine drive response to symmetrical and asymmetrical short circuit faults

    Page(s): 291 - 298
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (546 KB) |  | HTML iconHTML  

    A closed-form solution is presented for the steady-state response of interior permanent magnet (IPM) synchronous machines to symmetrical short circuits including the effects of q-axis magnetic saturation. Machine response to single-phase asymmetrical short circuits is also investigated. Experimental data are presented to verify predicted behavior for both types of short circuits. It is shown that single-phase asymmetrical short circuit faults produce more severe fault responses with high pulsating torque and a significant threat of rotor demagnetization. A control strategy that purposely transitions such faults into symmetrical three-phase short circuits can minimize the fault severity and associated demagnetization risks. Implications for the design of IPM machines with improved fault tolerance are discussed. View full abstract»

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  • A review of RFO induction motor parameter estimation techniques

    Page(s): 271 - 283
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (412 KB) |  | HTML iconHTML  

    An induction motor is the most frequently used electric machine in high performance drive applications. Control schemes of such drives require an exact knowledge of at least some of the induction motor parameters. Any mismatch between the parameter values used within the controller and actual parameter values in the motor leads to a deterioration in the drive performance. Numerous methods for induction machine online and offline parameter estimation have been developed exclusively for application in high performance drives. This paper aims at providing a review of the major techniques used for the induction motor parameter estimation. The paper is illustrated throughout with experimental and simulation examples, related to various parameter estimation techniques. View full abstract»

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  • Online identification of the mutual inductance for vector controlled induction motor drives

    Page(s): 299 - 305
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (401 KB) |  | HTML iconHTML  

    Mutual inductance of an induction machine may vary considerably when the flux reference varies. An important and frequent application of a variable flux reference is the operation in the field-weakening region. Standard assumption of constant mutual inductance is no longer valid and it becomes necessary to compensate for the mutual inductance variation. The paper proposes a novel method for online mutual inductance identification in vector controlled induction machines. The method is characterized with very simple structure, ease of implementation, very low parameter sensitivity, and capability to provide an accurate estimate under both transient and steady state operating conditions. Full experimental verification of the proposed scheme is provided and a number of potential applications in a vector controlled induction motor drive are discussed. View full abstract»

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  • Steady-state magnetic circuit analysis of salient-pole synchronous machines considering cross-magnetization

    Page(s): 213 - 218
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (494 KB) |  | HTML iconHTML  

    A simple magnetic circuit of salient-pole synchronous machines is presented. A method for calculating steady-state electrical performances using the circuit is described. Magnetic saturation including the cross-magnetizing phenomenon is considered in the method. The saturated reactances, field currents, and load angles are calculated easily from the method without much computational effort as compared with the finite element method. Despite the simplicity of the magnetic circuit, the calculated reactances at various load conditions using the method are close to the measured and FEM values. View full abstract»

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  • Multiphase space vector pulse width modulation

    Page(s): 259 - 264
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (437 KB) |  | HTML iconHTML  

    Pole-phase modulation adjusts the pole-phase ratio of an induction machine and requires a multileg, multiphase inverter. This paper analyzes an n-leg, n-phase inverter, and presents techniques for n-phase space vector pulse width modulation (SVPWM). In particular, nine-phase SVPWM is developed and implemented on a nine winding induction machine. The nine-phase SVPWM is compared to nine phase sine-triangle PWM in terms of DC bus utilization. View full abstract»

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  • Speed observer system for advanced sensorless control of induction motor

    Page(s): 219 - 224
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (455 KB) |  | HTML iconHTML  

    This paper presents a sensorless control system for induction motors, which is realized on a fixed-point digital signal processor (DSP) and field programmable gate arrays (FPGAs). An observer system has been developed for estimation of speed and the other state variables. The proposed observer system is verified for different conditions of motor operation. Experimental results for the control system fed by voltage source inverter controlled using predictive current controller are presented. View full abstract»

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  • Modeling and control of a wind turbine driven doubly fed induction generator

    Page(s): 194 - 204
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (795 KB) |  | HTML iconHTML  

    This paper presents the simulation results of a grid-connected wind driven doubly fed induction machine (DFIM) together with some real machine performance results. The modeling of the machine considers operating conditions below and above synchronous speed, which are actually achieved by means of a double-sided PWM converter joining the machine rotor to the grid. In order to decouple the active and reactive powers generated by the machine, stator-flux-oriented vector control is applied. The wind generator mathematical model developed in this paper is used to show how such a control strategy offers the possibility of controlling the power factor of the energy to be generated. View full abstract»

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  • An evaluation of inductances of a squirrel-cage induction motor under mixed eccentric conditions

    Page(s): 252 - 258
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (435 KB)  

    This paper presents a more precise model for computation of three-phase squirrel cage induction machine inductances under different eccentric conditions. Generally, available techniques are based on the winding function theory and simplification and geometrical approximation of unsymmetrical models of the motor under mixed eccentricities. This paper determines a precise geometrical model under the mixed eccentricity conditions and evaluates the inductances. Meanwhile, the evaluated inductances are compared to those calculated using different approximate geometrical models and the best approximation is recommended for a geometrical modeling of induction motor under eccentricity conditions. View full abstract»

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  • Conversion of unused heat energy to electricity by means of thermoelectric generation in condenser

    Page(s): 330 - 334
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (599 KB) |  | HTML iconHTML  

    Thermoelectric power generation has the potential to recover a large amount of energy loss at the vapor condensers in the steam-based power plants. A suitable arrangement of thermoelectric modules was designed from the heat transfer theory in the cylindrical heat exchanger. Even under the practical operation limits, 150 kW can be generated by the thermoelectric conversion. View full abstract»

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  • Online cage rotor fault detection using air-gap torque spectra

    Page(s): 265 - 270
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (518 KB) |  | HTML iconHTML  

    This paper discusses use of air-gap torque spectra as a means of identifying faults in cage rotors. Being dependent on both stator and rotor currents, the torque is very sensitive to faults in the rotor. Through a comparative study using a detailed machine model and the standard dq model, the paper shows that the characteristic frequencies generated by a particular fault are preserved even if the standard dq model is used for estimation of air-gap torque. This is validated through a practical hardware implementation for online spectrum estimation of air-gap torque using TMS320C31, where several faulted cage rotors were used for study. View full abstract»

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  • Influence of stator structure on electromechanical parameters of torus-type brushless DC motor

    Page(s): 231 - 237
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB) |  | HTML iconHTML  

    Five torus-type brushless DC motors, each with a different version of the stator core structure have been analyzed in the paper. The first one is a slotless stator core and the four others have the space between the adjacent coils of stator winding filled with the material made either of iron powder composite or laminated iron. An analysis of the motor performance is based on a three-dimensional (3-D) field motor model as well as on the circuit model of the inverter + motor set supplied from the battery. The toothed stator core versions show a significant increase of the average torque, and also an increase of torque ripple caused mainly by the rise of cogging torque. The analysis based on the simulation results is backed by measurements carried out on the prototype of slotless stator version of the motor. View full abstract»

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  • What stator current processing-based technique to use for induction motor rotor faults diagnosis?

    Page(s): 238 - 244
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (626 KB)  

    In recent years, marked improvement has been achieved in the design and manufacture of stator winding. However, motors driven by solid-state inverters undergo severe voltage stresses due to rapid switch-on and switch-off of semiconductor switches. Also, induction motors are required to operate in highly corrosive and dusty environments. Requirements such as these have spurred the development of vastly improved insulation material and treatment processes. But cage rotor design has undergone little change. As a result, rotor failures now account for a larger percentage of total induction motor failures. Broken cage bars and bearing deterioration are now the main cause of rotor failures. Moreover, with advances in digital technology over the last years, adequate data processing capability is now available on cost-effective hardware platforms, to monitor motors for a variety of abnormalities on a real time basis in addition to the normal motor protection functions. Such multifunction monitors are now starting to displace the multiplicity of electromechanical devices commonly applied for many years. For such reasons, this paper is devoted to a comparison of signal processing-based techniques for the detection of broken bars and bearing deterioration in induction motors. Features of these techniques which are relevant to fault detection are presented. These features are then analyzed and compared to deduce the most appropriate technique for induction motor rotor fault detection. View full abstract»

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  • Sensorless sliding-mode control of induction motors using operating condition dependent models

    Page(s): 205 - 212
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB) |  | HTML iconHTML  

    A sensorless torque control system for induction motors is developed. The system allows for fast and precise torque tracking over a wide range of speed. The paper also presents the identification and parameter estimation of an induction motor model with parameters varying as functions of the operating conditions encountered in hybrid electric vehicles applications. An adaptive sliding mode speed-flux observer is developed and a cascade of discrete time sliding mode controllers is used for flux and current control. Simulation and experimental results prove the validity of the approach. View full abstract»

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  • Adaptive control of a fuel cell-microturbine hybrid power plant

    Page(s): 342 - 347
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (337 KB)  

    The composition of natural gas may vary significantly, and load power varies randomly. Traditional control design approaches consider a fixed operating point in the hope that the resulting controller is robust enough to stabilize the system for different operating conditions. On the other hand, adaptive control incorporates the time-varying dynamical properties of the model and considers the disturbances acting at the fuel cell-microturbine hybrid power plant. It may be possible to identify the parameters of the adaptive controller. This scheme is called direct adaptive control, because we are going to obtain directly the required controller parameters through their estimation in an appropriately redefined plant model. An adaptive minimum variance controller is developed in this paper. View full abstract»

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  • A comprehensive method for the calculation of inductance coefficients of cage induction machines

    Page(s): 187 - 193
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (521 KB)  

    In this paper, a new comprehensive method for the calculation of inductance coefficients of squirrel cage induction machine based on combined winding function approach (WFA) and magnetic equivalent circuit (MEC) is presented. By taking into account machine geometry, rotor skewing, stator and rotor slots effects and type of windings connection, this method is able to model most of the important features of an induction machine. The effects of each machine parameter on the inductance coefficients are verified. Also, effects of several rotor asymmetries on these inductances are shown. Simulation results are verified by more elaborate nonlinear finite element model and finally with experimental results. View full abstract»

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  • Innovative remedial strategies for inverter faults in IPM synchronous motor drives

    Page(s): 306 - 314
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (601 KB) |  | HTML iconHTML  

    Interior permanent-magnet (PM) synchronous motors are extensively used in many industrial drives and the development of fault-tolerant control techniques may extend their use to applications where high reliability, also in the flux-weakening region, is a key feature. This paper proposes some innovative fault-remedial control strategies for failures occurring in the drive voltage inverter. View full abstract»

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  • A frequency domain approach to wind turbines for flicker analysis

    Page(s): 335 - 341
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (546 KB)  

    Wind turbines may have an important impact on power quality. Flicker is a more serious issue for fixed-speed wind turbines because these turbines produce electric power following the variations of the incident wind. During continuous operation, wind variations will result in power fluctuations and consequently in voltage fluctuations. It is necessary to evaluate wind turbines flicker emission level, and traditionally time domain simulations have been used to perform the analysis. This paper presents a complete frequency domain model to study flicker produced during wind turbines continuous operation. The model includes a realistic wind speed model as observed by the wind turbine and also a frequency domain induction generator model is presented. The frequency domain model has been compared with a time domain model. The frequency domain approach, as shown in the paper, may be very useful for flicker analysis in electric networks. View full abstract»

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  • Sensorless scalar-controlled induction motor drives with modified flux observer

    Page(s): 181 - 186
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB) |  | HTML iconHTML  

    This paper presents a simple sensorless scalar control algorithm to control the speed of an induction motor. First, a modified flux observer was employed to estimate the stator flux with the voltage command and the feedback current. Then, based on the mathematical model of the induction motor, the slip frequency was calculated, and the frequency of the voltage command was compensated. An auto-boost controller was designed to overcome the decrease in voltages of the stator resistance and to maintain constant stator flux amplitude. To improve the pure integration problem, a highpass filter was installed in the stator flux observer. In this filter, the cut-off frequency is proportional to the voltage frequency; therefore, the phase shift and amplitude degradation of the estimated flux can be corrected easily. Finally, to demonstrate the proposed control algorithm, a PC-based experimental system was constructed in a 1-hp induction motor. Experimental results are presented to validate the effectiveness of our design. View full abstract»

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  • Application of AI tools in fault diagnosis of electrical machines and drives-an overview

    Page(s): 245 - 251
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (297 KB) |  | HTML iconHTML  

    Condition monitoring leading to fault diagnosis and prediction of electrical machines and drives has recently become of importance. The topic has attracted researchers to work in during the past few years because of its great influence on the operational continuation of many industrial processes. Correct diagnosis and early detection of incipient faults result in fast unscheduled maintenance and short down time for the machine under consideration. It also avoids harmful, sometimes devastative, consequences and helps reduce financial loss. Reduction of the human experts involvement in the diagnosis process has gradually taken place upon the recent developments in the modern artificial intelligence (AI) tools. Artificial neural networks (ANNs), fuzzy and adaptive fuzzy systems, and expert systems are good candidates for the automation of the diagnostic procedures. This present work surveys the principles and criteria of the diagnosis process. It introduces the current research achievements to apply AI techniques in the diagnostic systems of electrical machines and drives. View full abstract»

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  • A doubly-fed induction machine differential drive model for automobiles

    Page(s): 225 - 230
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (450 KB)  

    In this paper, an electrical drive model, implementing a doubly-fed differential drive (DFDD) is presented. Two doubly-fed induction machines, having the corresponding rotor phases connected, constitutes the differential wheel drive. Two inverters are supplying the machine stators with three-phase power of variable magnitude and frequency. The power required to supply the inverters may be delivered from a constant voltage DC source like a battery. Active power requirements for the machines and the inverters over the DFDD speed range may be obtained. Reactive power requirements for minimum copper loss may be derived as well. The DFDD may provide propulsion to electrical vehicles. 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.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Juri Jatskevich
University of British Columbia