共查询到20条相似文献,搜索用时 31 毫秒
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A novel concept for power factor correction of induction machines is introduced that employs an auxiliary three-phase stator winding together with a pulse-width-modulated (PWM) inverter to supply excitation power to the machine. When the PWM inverter is modeled as an equivalent capacitor, it is shown that two values of capacitance will yield unity power factor at a given operating condition. The effect of machine parameters on the critical value of capacitance is examined. A control algorithm to ensure unity power factor at the terminals of the main stator windings is presented, and its satisfactory operation is verified by means of a detailed analog computer simulation 相似文献
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Boglietti A. Bojoi R. Cavagnino A. Tenconi A. 《Industrial Electronics, IEEE Transactions on》2008,55(5):2015-2023
A performance analysis of three-phase and dual three-phase (DTP) induction pulsewidth modulation (PWM) inverter-fed motor drives is conducted in this paper. The focus is on the efficiency performance of high-frequency DTP machines compared to their three-phase counterparts in low/medium power applications. For this purpose, a DTP machine, having two sets of stator three-phase windings spatially shifted by 30 electrical degrees (asymmetrical six-phase winding configuration), was tested for both six-phase and three-phase winding configurations under the same magnetic conditions. Simulation and experimental results are presented to evaluate the efficiency performance of three-phase and dual-three induction motor drives employing PWM voltage source inverters. 相似文献
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The emergence of high Tc superconducting (HTS) wires with large critical current densities allows the design and construction of many applications, for example, rotating electrical machines. Nevertheless, the current “state of the art” of Bi “powder in tube” wires, the most advanced HTS conductor, is not adequate for an ac operation. We thus propose a fully superconducting synchronous machine with an NbTi stationary 4 K armature and a rotating Bi-2223 field winding at 20 or 40 K. Thanks to the armature cryogenic environment, the cooling of the Bi coils is very simple. The conceptual design of a typical machine is suggested and several electromagnetic designs are presented. The first one deals with a Bi field winding adapted to an existing NbTi armature of a tenth of kYA. Afterwards, large torque motors are theoretically designed comparing the high (at 20 and 40 K) and low Tc field winding solutions. The results are comparable for NbTi and Bi at 20 K. But with a Bi field winding operating at 40 K, the performances are degraded. Otherwise, at 4 or 20 K fully superconducting motors show high performances in terms of weight, volume, and efficiency. Nevertheless, the Bi field windings require a large amount of material indicating that improvements in critical current density are needed 相似文献
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Xiaoping Tu Dessaint L.-A. Fallati N. Bruno De Kelper 《Industrial Electronics, IEEE Transactions on》2007,54(3):1400-1409
In large synchronous generators, the stator windings are usually parallel-connected in order to increase the machine current capacity. In analysis and modeling, the parallel windings are usually lumped into one equivalent stator winding since equal currents flow in these windings. However, when an internal fault occurs in the windings, the symmetry between the parallel windings is broken and different currents will flow in the parallel windings since unsymmetrical magnetic linkage may exist between the stator windings. The aim of this paper is to present a simulation model to investigate the internal fault currents of large synchronous generators with parallel-connected windings. This model is based on a modified winding function theory that takes into account all space harmonics. Moreover, the calculation of the machine inductances is made easier by the use of the machine electrical parameters instead of the geometrical ones. The simulation results illustrate the existence of different currents in parallel windings in the case of internal faults. Results are given for an implementation of the internal fault model in a real-time simulator of large power networks 相似文献
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Tu X. Dessaint L.-A. El Kahel M. Barry A. O. 《Industrial Electronics, IEEE Transactions on》2006,53(6):1818-1828
A synchronous machine internal faults model based on the actual winding arrangement is described in this paper. Based on the winding function approach, the machine inductances are calculated directly from the machine winding distribution, thereby the space harmonics produced by the machine windings are readily taken into account. Moreover, the calculation of the machine inductances is made easier by the use of the machine electrical parameters instead of the geometrical ones. Simulation results for internal faults on a laboratory generator are compared with experimental results to verify the accuracy of the proposed model 相似文献
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Mohapatra K.K. Kanchan R.S. Baiju M.R. Tekwani P.N. Gopakumar K. 《Industrial Electronics, IEEE Transactions on》2005,52(5):1372-1382
Split-phase (six-phase) induction motor stator windings consist of two sets of three phase windings, which are spatially phase separated by 30 electrical degrees. Due to mutual cancellation of the air gap flux for all the 6n/spl plusmn/1 (n=1,3,5...) order harmonic voltages, called zero sequence components, large harmonic currents are generated in the stator phases. Only the 12n/spl plusmn/1 (n=0,1,2,3...)-order harmonic voltage components contribute toward the air gap flux and electromagnetic torque production in the machine. In this paper, a novel scheme is proposed where two six-phase induction motors are connected in series with proper phase sequence so that the zero sequence component voltages of one machine act as torque and flux producing components for the other. Thus, the two six-phase motors can be independently controlled from a single six-phase inverter. A vector control scheme for the dual motor drive is developed and experimentally verified in this paper. 相似文献
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Multiphase machines are gaining attention in specific applications due to their increased reliability and the possibility to split the power between more than one inverter. Dual stator winding machines can be seen under certain conditions as two independent induction machines coupled by the rotor. To ensure control independence of both windings, airgap flux saturation must be avoided. Proper flux synchronization of both windings is required to achieve this goal while maximizing the torque per ampere ratio of the machine. The conditions to obtain proper orientation of the fluxes are discussed in this paper, and the inverter control scheme to perform such orientation is developed. 相似文献
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《Mechatronics》2014,24(8):1050-1058
The sidebands around stator currents harmonics as a potential tool for supporting the diagnosis of rotor faults in induction motors are analyzed in this paper. The presence of broken bars introduces high frequency components in the machine currents spectrum in addition to the characteristic sidebands around the fundamental component. These additional components are due to the interaction between, rotor asymmetry and either the voltage harmonics, or winding distribution, or rotor slots. In particular, the components at frequencies near to fifth and seventh harmonics, produced by the interaction between the rotor faults and the harmonics of the spatial distribution of stator windings, are analyzed in this work. A multiple coupled circuit model of the induction motor is used to evaluate the sensitivity of these components for different stator winding configurations, load level, supply voltage conditions, and different number of broken bars. Simulation results showed that a particular analyzed component near to fifth harmonic depends mainly on fifth harmonic of winding distribution, which remains almost constant for most common distributions. Therefore, it is expected that this component should be found in most motors with broken bars. Finally, experimental laboratory results and two industrial cases that validate the analysis are presented. 相似文献
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《Industrial Electronics, IEEE Transactions on》2008,55(12):4238-4251
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J. W. Kolar ÖVE IEEE IEEJ VDE H. Ertl ÖVE R. S. Wieser ÖVE M. Schrödl ÖVE 《e & i Elektrotechnik und Informationstechnik》2000,117(2):134-140
The paper presents an inverter concept for the realization of an induction machine drive with an extremely wide constant power range. The stator winding of the induction machine is split up into two isolated and quasi-bifilar wound three-phase winding systems. The series operation of the two winding sets provides very high torque at low stator frequencies while keeping the machine terminal and the inverter DC link current relatively low. However, due to the high number of turns field weakening is necessary at low frequencies (approximately at 50% of rated speed) already. Nevertheless, with the help of an electronic transition from series to parallel stator winding arrangement the machine flux can be restored to its nominal value as given for rated machine speed. Consequently, the break-down torque is increased by a factor of 4 which gives the basis for a high maximum speed with constant machine power. 相似文献
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De Camillis L. Matuonto M. Monti A. Vignati A. 《Power Electronics, IEEE Transactions on》2001,16(5):676-685
The operation of AC drives in applications requiring high overload capability imposes hard working conditions on the electronic switching devices. The use of induction motors with two stator windings, fed by two inverter modules, allows large power rating in variable speed drives for high performance applications. This paper shows the structure and the main features of a field-oriented control for a double winding motor, fed by two GTO inverters. The operational results of an 850 kW drive, working as a melt pump in a polyethylene plant, are reported in order to describe the obtained performances 相似文献
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M. Jannati A. Monadi N.R.N. Idris A.A.M. Faudzi 《International Journal of Electronics》2016,103(5):775-793
This study discusses the different techniques for speed control of single-phase induction motor with two asymmetrical main and auxiliary windings based on Rotor Field-Oriented Control (RFOC) method. In the presented methods, transformation matrices are introduced and applied to the equations of single-phase induction motor. It is shown by applying these rotational transformations to the unbalanced equations of single-phase induction motor, equations of single-phase induction motor are transformed into symmetrical equations. These rotational transformations are achieved based from the steady-state equivalent circuit of single-phase induction motor. Finally, a method for RFOC of single-phase induction motor is proposed. Results show the good performance of the proposed method. 相似文献
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Staines C.S. Caruana C. Asher G.M. Sumner M. 《Industrial Electronics, IEEE Transactions on》2006,53(1):195-206
This paper considers both flux and rotor position estimations for sensorless control of delta-connected cage induction machines (IMs) at low and zero frequency operation. The variation of leakage inductance due to either saturation or rotor slotting is tracked by measuring the derivative of the zero sequence current in response to the application of appropriate voltage test vectors. The method requires only a single extra sensor. It requires access to machine phase windings and is appropriate for integrated-type induction motor drives. Both a closed-slot and an open-slot machine is used to demonstrate rotor flux and rotor position tracking, respectively. Experimental results are presented showing sensorless torque control and sensorless speed and position control at low and zero frequencies. 相似文献
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A power control system for a doubly fed wound rotor induction generator has been developed. This power control system applies a control method using a rotating reference frame fixed on the gap flux of the generator, and can control active and reactive power independently and stably. The characteristics of the control system have been proved by experiment. Harmonic currents fed to the rotor windings are transmitted to the stator winding changing its frequency. The transmitting characteristics of the harmonic currents have been analyzed and verified by experiments 相似文献
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《Industrial Electronics, IEEE Transactions on》2008,55(12):4277-4289
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A progress report on the program at MIT to demonstrate the feasibility and potentials for the application of superconductors in the rotating field windings of large central station synchronous generators is presented. A brief history of the program and a synopsis of previously reported results are given. The second ex-experimental machine (which will have a rating of about 2 MVA) is described. 相似文献
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Independent Control of Average Torque and Radial Force in Bearingless Switched-Reluctance Motors With Hybrid Excitations 总被引:1,自引:0,他引:1
《Power Electronics, IEEE Transactions on》2009,24(5):1376-1385
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Acero J. Alonso R. Burdio J.M. Barragan L.A. Puyal D. 《Power Electronics, IEEE Transactions on》2006,21(4):856-866
In this paper, the frequency-dependent resistance in Litz-wire planar windings for domestic induction heating appliances is analyzed. For these inductors, in which the size is not an essential constraint, an analytical model is developed based on the superposition of different loss effects in the wire. Eddy current losses, including conduction losses and proximity-effect losses, both internal and external, were considered and modeled. The magnetic field necessary to evaluate the external proximity losses is as well analytically calculated considering the complete winding and load properties. To verify this model and its limitations, several inductors with different wires and numbers of turns were constructed and results with both non-loaded and loaded inductors are compared with theoretical predictions. 相似文献