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Energy Conversion, IEEE Transactions on

Issue 2 • Date June 2000

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Displaying Results 1 - 16 of 16
  • Dynamic simulation of dynamic eccentricity in induction machines-winding function approach

    Page(s): 143 - 148
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB)  

    The paper describes a method for the dynamic simulation of dynamic rotor eccentricity in squirrel cage rotor induction machines. The method is based on a winding function approach, which allows for all harmonics of magnetomotive force to be taken into account. It is demonstrated how this complex dynamic regime can be modeled using the mutual inductance curves of symmetrical machine using proper scaling techniques. Experimental results demonstrate the effectiveness of the proposed technique and validate the theoretical analysis. View full abstract»

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  • Impact of dynamic cross-saturation on accuracy of saturated synchronous machine models

    Page(s): 224 - 230
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    Cross-saturation effect in synchronous machines has been a subject of considerable attention. Inclusion of the cross-saturation in the machine model has two consequences. The first one, called here “steady-state cross-saturation”, consists of dependence of the steady-state d-q axis magnetizing inductances on the currents in both axes. The second one, termed here “dynamic cross-saturation”, is the existence of nonzero elements in the system matrix, that describe cross coupling between d- and q-axis. Dynamic cross-saturation appears in all the saturated machine models, regardless of the selected set of state-space variables, with the exception of the winding flux linkage state-space model. The aim of this paper is to compare behavior of various models when dynamic cross-saturation is neglected. It is shown that the impact of dynamic cross-saturation on accuracy depends on the selected set of state-space variables. In the majority of cases omission of dynamic cross-saturation leads to very inaccurate results. However, it is found that for one particular class of models, omission of dynamic cross-saturation has practically no impact on accuracy. These models therefore fully describe the complete saturation effect by means of only continuous variation of the d-q axis magnetizing inductances View full abstract»

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  • A three-phase multi-stress accelerated electrical aging test facility for stator bars

    Page(s): 149 - 156
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB)  

    A full scale three-phase multi-stress accelerated electrical aging test facility for stator bars is described. Electrical aging characteristics may be determined under simultaneous electrical, mechanical and electrical stress at either 60 Hz or an accelerated frequency of 400 Hz. Typical initial aging data are presented and discussed View full abstract»

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  • Identification of armature, field, and saturated parameters of a large steam turbine-generator from operating data

    Page(s): 181 - 187
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB)  

    This paper presents a step by step identification procedure of armature, field and saturated parameters of a large steam turbine-generator from real time operating data. First, data from a small excitation disturbance is utilized to estimate armature circuit parameters of the machine. Subsequently, for each set of steady state operating data, saturable mutual inductances Lads and Laqs are estimated. The recursive maximum likelihood estimation technique is employed for identification in these first two stages. An artificial neural network (ANN) based estimator is used to model these saturated inductances based on the generator operating conditions. Finally, using the estimates of the armature circuit parameters, the field winding and some damper winding parameters are estimated using an output error method (OEM) of estimation. The developed models are validated with measurements not used in the training of ANN and with large disturbance responses View full abstract»

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  • Nonlinear control of a permanent magnet synchronous motor with disturbance torque estimation

    Page(s): 163 - 168
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB)  

    This paper introduces a sensorless nonlinear control scheme for controlling the speed of a permanent magnet synchronous motor (PMSM) driving an unknown load torque. The states of the motor and disturbance torque are estimated via an extended nonlinear observer avoiding the use of mechanical sensors. The control strategy is an exact feedback linearization law, with trajectory tracking evaluated on estimated values of the PMSM states and the disturbance torque. The system performance is evaluated by simulations View full abstract»

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  • Bidirectional starting of a symmetrical two-phase switched reluctance machine

    Page(s): 211 - 217
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    The mechanical and electrical properties of the two-phase 4/2 switched reluctance machine make it suitable for high-speed operation. Its adoption in such applications has been hindered by a perceived starting problem especially if starting in both directions is required. A starting technique is proposed which exploits the natural magnetic asymmetry in the symmetrical machine geometry and provides for bidirectional torque production at start-up. The approach utilizes mutual coupling in the machine, an effect not previously identified for starting. The technique requires no modifications to either stator or rotor poles, and is suitable for fan applications which require only low starting torques. The starting technique is described and tested with nonoriented silicon steel and GOSS rotors, and starting torque from machine experimentally determined View full abstract»

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  • A systematic method for the determination of the parameters of synchronous machines from the results of frequency response tests

    Page(s): 218 - 223
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (132 KB)  

    This paper deals with the analysis of the frequency responses of the d and q axis impedances of synchronous machines. Numerical curve-fitting techniques have normally been used to find the best set of time constants to fit the frequency response data, but limitations or constraints are introduced with these techniques. The process to be described here is based on characteristic features of the equivalent circuits which overcome the need to make the assumptions inherent in a numerical approach. The extraction process is demonstrated using an equivalent circuit chosen to produce a frequency response similar to that for the direct axis of a production machine. This enables the intrinsic advantages of the proposed process for extraction of the time constants to be demonstrated which then leads directly to a unique set of equivalent circuit parameters View full abstract»

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  • A novel 16/6 phase modulated winding

    Page(s): 188 - 190
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    Many authors have presented various types of wide ratio pole changing windings. Some have done that using the principles of pole amplitude modulation (PAM) technique and others have resorted to the use of phase modulating (PM) technique. It has been reported that difficulties arise for wide ratio phase modulated windings when one of the pole numbers is triplen. This paper presents a novel wide ratio phase modulated winding which includes a triplen pole number View full abstract»

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  • Thermal behavior of an electrical motor through a reduced model

    Page(s): 129 - 134
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB)  

    The aim of this study is to obtain quickly thermal information on some sensitive components of an electrical motor in a short lapse of time. The thermal behavior of this complex system is modeled and validated. The corresponding detailed model leads to the resolution of a linear system of differential equations of high order, but is not easy to handle for control purposes, due to long CPU time. In order to compute faster, two model reduction techniques are used: the Eitelberg method and the reduction by modal identification. The reduced models effectively give good temperature accuracy on the critical points of the motor with very fast computation time View full abstract»

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  • A multiple reference frame synchronous estimator/regulator

    Page(s): 197 - 202
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    A synchronous regulator that accurately tracks three-phase commands with arbitrary balanced harmonic content is set forth. The regulator utilizes multiple reference frames to realize both a novel harmonic estimator and an integral feedback controller. The regulator is analyzed and demonstrated in the context of a permanent-magnet synchronous machine drive. The drive utilizes an optimized nonsinusoidal current command to achieve superior efficiency and torque ripple performance but which is dependent upon the commanded waveforms being precisely realized. The multiple reference frame synchronous current regulator proposed herein readily achieves this requirement. A computer simulation and a hardware prototype demonstrate validity of the regulator View full abstract»

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  • Effect of combined velocity and pressure on life time of carbon brushes

    Page(s): 176 - 180
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    The value of contact resistance between copper sliprings and carbon brushes, in wound-rotor induction motors, has a profound effect on the performance of these machines. The increase of this resistance due to bad contact may be detrimental. In this paper, an important factor affecting the resistance is introduced. This is the PV factor (product of contact pressure and peripheral speed). It represents the frictional power density at the interface; and it is also an indication of the volumetric or linear wear rate. A relation between the operational life time of brushes and the PV factor is experimentally deduced View full abstract»

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  • A method for magnetizing curve identification in rotor flux oriented induction machines

    Page(s): 157 - 162
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (104 KB)  

    Operation of an indirect rotor flux oriented induction machine in the field weakening region is usually realized by varying the rotor flux reference in inverse proportion to the speed of rotation. In order to provide the correct stator d-axis current reference at all speeds, it is necessary to incorporate the inverse magnetizing curve of the machine in the controller. The paper proposes an experimental method for identifying the inverse magnetizing curve, specifically developed for the type of vector controlled drives described. The method utilizes the same indirect vector controller and PWM inverter that are used in subsequent normal operation of the drive. It requires that the machine can run under no-load conditions and that the fundamental component of the stator voltage can be measured. The simplicity and accuracy of the method make it well suited for use during commissioning of the drive. The method is verified by extensive experimentation View full abstract»

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  • A hysteresis current-regulated control for multi-level drives

    Page(s): 169 - 175
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    Most multi-level converters are controlled through the use of voltage-source based control techniques such as space-vector modulation or multi-level sine-triangle modulation. However, in many applications such as field oriented drives, a high bandwidth current-source inverter based control is more desirable. In this paper, the concept of a multi-level hysteresis current-source control is set forth. The new control is experimentally verified using a four-level converter/induction motor drive system and the results are compared to a space vector modulation controller. A dynamic study involving a step change in current command demonstrates the controls high bandwidth View full abstract»

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  • Computer analysis of voltage recovery and field decay test responses

    Page(s): 191 - 196
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    Voltage recovery and field decay test responses are digitally recorded and parameter values extracted by nonlinear curve fitting. The proposed method combines the three phase responses into axis quantities making envelope construction unnecessary. Results obtained from tests conducted at different voltages are quoted and the effects of saturation on parameter values discussed. Influence of the brushless exciter on voltage recovery is also investigated View full abstract»

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  • Magnetic and thermal performance of a synchronous motor under loss minimization control

    Page(s): 135 - 142
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB)  

    The steady state magnetic and thermal performance of a wound-field cylindrical rotor synchronous motor under loss minimization control is investigated. The calculated magnetic field waveforms are presented and it is shown that loss minimization control decreases the magnetic saturation. It is also proved that although the optimal stator current is increased, the temperature is decreased in all parts of the motor. Theoretical and experimental results are presented to verify the operational improvements View full abstract»

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  • A synchronous/permanent magnet hybrid AC machine

    Page(s): 203 - 210
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB)  

    In this paper, a synchronous/permanent magnet hybrid (SynPM) machine is presented. It is shown that the machine has good power density and efficiency, and that the machine has true field regulation capability. The principle of operation, finite element analysis and simulation of this new machine are investigated in the paper 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