The Experts below are selected from a list of 15672 Experts worldwide ranked by ideXlab platform
Liwei Zhang - One of the best experts on this subject based on the ideXlab platform.
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A Rotor Flux oriented scheme of induction machine based on voltage controller
2010 5th IEEE Conference on Industrial Electronics and Applications, 2010Co-Authors: Minglei Zhou, Chenchen Wang, Jian Wang, Liwei ZhangAbstract:The performance of the induction machine driving system with indirect vector control can easily be influenced by the effects of parameter mismatch and eddy current, which result that the magnetizing component of stator current can't align with the Rotor Flux vector, especially in the range of high speed and Flux weakening. In order to achieve accurate Rotor Flux orientation, a novel control strategy based on the voltage controller is proposed in this paper. The relation between the phase voltage of the induction machine and the accuracy of the field orientation is analyzed and a voltage controller is used to eliminate the angle between the d-axis and the Rotor Flux vector due to the incorrect orientation. The simulation results show that the performance of the driving system in the whole speed region can be improved obviously. So, the robustness of the control system to the motor parameters, especially to the Rotor time constant is raised highly.
P.p. Acarnley - One of the best experts on this subject based on the ideXlab platform.
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Sensorless Indirect Rotor Field Orientation Speed Control Of Permanent Magnet Synchronous Motor Using Adaptive Rotor Flux Estimator
Proceedings of the 44th IEEE Conference on Decision and Control, 1Co-Authors: Mohamed Rashed, P.f.a. Macconnell, A. Stroncach, P.p. AcarnleyAbstract:Efficient and precise sensorless spped control of permanent Magnet Synchronous Motor (PMSM) requires accurate knowledge of Rotor Flux position and speed. In the present paper, an indirect Rotor Flux oriented scheme for sensorless speed control of PMSM is proposed in which the Rotor Flux position is estimated by direct integration of the estimated Rotor spped to reduce the effect of system noise. The Rotor Flux magnitude and the Rotor Flux spped are estimated adaptively using stable Model Reference Adaptive System (MRAS) estimators. Simple stability analysis and design of the estimators are performed using linear control theory. The convergence of Rotor position and speed estimation errors to zero is guaranteed. Simulation and experimental results obtained show excellent performance.
Chun-chieh Wang - One of the best experts on this subject based on the ideXlab platform.
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A Rotor-Flux-observer-based composite adaptive speed controller for an induction motor
IEEE Transactions on Energy Conversion, 1997Co-Authors: Wen-jieh Wang, Chun-chieh WangAbstract:A composite adaptive speed controller for an induction motor based on a Rotor-Flux-observer is proposed in this paper. The Rotor Flux is estimated with the simplified Rotor-Flux-observer on the Rotor reference frame and the input-output linearization theory is used to decouple the motor speed and the Rotor Flux. Then, the composite adaptive algorithm is used as the speed controller of the induction motor drive. The resulting system is verified to be stable. Some experimental results are provided to demonstrate the effectiveness of the proposed adaptive controller. Good speed tracking and load regulating responses can be obtained by the proposed composite adaptive controller. Moreover, the system can be operated in a wide range of speed and is robust to parameter variations.
Slobodan N Vukosavic - One of the best experts on this subject based on the ideXlab platform.
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a method for magnetizing curve identification in Rotor Flux oriented induction machines
IEEE Transactions on Energy Conversion, 2000Co-Authors: E Levi, M. Sokola, Slobodan N VukosavicAbstract: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.
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Identification of the magnetising curve during commissioning of a Rotor Flux oriented induction machine
IEE Proceedings - Electric Power Applications, 1999Co-Authors: Emil Levi, Slobodan N VukosavicAbstract:Numerous operating regimes of a Rotor Flux oriented induction machine require variation of the Rotor Flux reference. Correct setting of the stator d-axis current reference for each value of the Rotor Flux reference is only possible if an approximation of the magnetising curve of the machine is incorporated in the control system. Consequently, the magnetising curve has to be identified during commissioning of the drive. An experimental method for identification of the magnetising curve is proposed, developed specifically for vector controlled drives. The method utilises the same vector controller and the same PWM inverter used in normal operation of the drive. The identification relies on the signals that are already present within the drive controller (stator currents only, or stator currents and the DC link voltage), so that additional measurements are not required. The identification function proposed ensures precise acquisition of the magnetising curve, robust against the stator resistance variation and the inverter lock-out time. The algorithm does not require any test signals. It is sufficient to perform the measurements during running of the unloaded motor at around 100 rpm. The developed procedure is verified by extensive experimentation and is believed to be well-suited for application during commissioning of the drive, provided that rotation is permitted.
Emil Levi - One of the best experts on this subject based on the ideXlab platform.
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Magnetic saturation in Rotor‐Flux‐oriented induction motor drives: operating regimes, consequences and open‐loop compensation
European Transactions on Electrical Power, 2007Co-Authors: Emil LeviAbstract:Parameter variation effects infield-oriented induction machines can cause significant performance deterioration. Magnetic saturation of the main Flux path is one of the sources of parameter variations, caused by non-linear nature of the magnetizing curve. The paper at first discusses operating regimes of a Rotor-Flux-oriented machine which lead to operation with variable main Flux in the machine. These are shown to be operation with variable stator d-axis current command during forced excitation and in field-weakening region, and operation with variable q-axis current command during rapid speed changes when cross-saturation effect causes variable main Flux operation. Actual effects of variable saturation level on performance of the drive are assessed by simulation. Modified Rotor Flux estimation schemes are then derived, which enable instantaneous open-loop adaptation to actual saturation degree in the machine. The proposed adaptive Rotor-Flux estimators are verified by simulation and some experimental results are included as well. As the saturated induction machine representation is based on the current state-space model, while the modified Rotor-Flux estimator relies on the Flux state-space model, the performed simulation study shows that current state-space model and Flux state-space model, although considerably different in their appearance, account for the main Flux saturation in basically the same way.
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Identification of the magnetising curve during commissioning of a Rotor Flux oriented induction machine
IEE Proceedings - Electric Power Applications, 1999Co-Authors: Emil Levi, Slobodan N VukosavicAbstract:Numerous operating regimes of a Rotor Flux oriented induction machine require variation of the Rotor Flux reference. Correct setting of the stator d-axis current reference for each value of the Rotor Flux reference is only possible if an approximation of the magnetising curve of the machine is incorporated in the control system. Consequently, the magnetising curve has to be identified during commissioning of the drive. An experimental method for identification of the magnetising curve is proposed, developed specifically for vector controlled drives. The method utilises the same vector controller and the same PWM inverter used in normal operation of the drive. The identification relies on the signals that are already present within the drive controller (stator currents only, or stator currents and the DC link voltage), so that additional measurements are not required. The identification function proposed ensures precise acquisition of the magnetising curve, robust against the stator resistance variation and the inverter lock-out time. The algorithm does not require any test signals. It is sufficient to perform the measurements during running of the unloaded motor at around 100 rpm. The developed procedure is verified by extensive experimentation and is believed to be well-suited for application during commissioning of the drive, provided that rotation is permitted.
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Modelling and simulation of a stand-alone induction generator with Rotor Flux oriented control
Electric Power Systems Research, 1998Co-Authors: Y.w. Liao, Emil LeviAbstract:The paper deals with a variable-speed induction generator, aimed at supplying an autonomous power system. Reactive power requirements of the generator are met by a static reactive power compensator of voltage source inverter (VSI) type. Control of the compensator is achieved using Rotor Flux oriented control principles. Detailed mathematical modelling of all the components of the system under consideration is described. Induction generator is represented with an appropriate saturated machine model and a novel, saturation adaptive, Rotor Flux estimator is used to achieve correct field orientation under all operating conditions. Dynamics of self-excitation process, step application of a three-phase load and variable speed operation are simulated. Excellent tracking of Rotor Flux reference is achieved under all operating conditions, including operation with speeds higher than rated.
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Rotor Flux COMPUTATION IN SATURATED FIELD-ORIENTED INDUCTION MACHINES
Electric Machines & Power Systems, 1993Co-Authors: Emil Levi, Vladan VučkovićAbstract:ABSTRACT The paper discusses effects of main Flux saturation in field–oriented induction machines and proposes improved schemes for Rotor Flux space vector calculation. Field–oriented control with Rotor Flux computation out of the measured quantities is elaborated. Two Rotor Flux computer structures are analyzed. The first one is based on stator voltages and currents as measured variables, while the second scheme carries out calculations on the basis of sensed stator currents and Rotor speed (position). The sensitivity of the constant parameter Rotor Flux computers to saturation degree variation is investigated in detail. Modified structures of the computing schemes are then proposed, which account for change in saturation level in the machine. The modified Rotor Flux calculators are derived from Flux state–space model of a saturated induction machine. Accurate computation of Rotor Flux space vector is enabled in this way, irrespective of the actual saturation level in the machine. Verification of the dev...
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Representation and compensation of iron loss in Rotor Flux oriented induction machines
Proceedings of International Conference on Power Electronics Drives and Energy Systems for Industrial Growth, 1Co-Authors: M. Sokola, Emil Levi, G. Jamieson, D. WilliamsAbstract:Representation of stator iron loss in d-q axis models of induction machines may be done in a number of different, but always approximate ways. On the other hand, vector control principles are derived under the assumption that iron loss may be neglected. Studies of detuning caused by iron loss in indirect schemes of vector control indicate that the impact of iron loss on accuracy of field orientation is not always negligible. This paper concentrates on a direct Rotor Flux oriented control scheme with Rotor Flux estimation on the basis of measured stator currents and Rotor speed (i-/spl omega/ estimator) and examines at first detuning during dynamic operation caused by iron loss. An induction machine with included iron loss is represented for simulation purposes with a number of different models and the impact of induction machine model on simulated behaviour of the drive is assessed. The Rotor Flux estimator used in this part of the study is the standard i-/spl omega/, scheme with neglected iron loss. The second part of the paper presents a modified i-/spl omega/ estimator that provides compensation for iron loss. It is shown that satisfactory compensation is achievable with an estimator that is insignificantly more complex than the standard one with neglected iron loss.
