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Showing papers on "Induction motor published in 2003"


Journal ArticleDOI
TL;DR: A simple and robust sensorless technique for online stator winding turn fault detection based on monitoring an off-diagonal term of the sequence component impedance matrix is proposed in this paper.
Abstract: A simple and robust sensorless technique for online stator winding turn fault detection based on monitoring an off-diagonal term of the sequence component impedance matrix is proposed in this paper. Due to the destructive and rapidly propagating nature of insulation failure, it is critical to detect turn faults in an early stage to prevent further damage to the motor. The motor nonidealities such as the variation in the supply voltage unbalance, slip-dependent influence of inherent motor asymmetry, and measurement errors must be taken into account in order to reliably detect a turn fault in its incipient stage. Simulation and experimental results on a 5 hp induction machine are given to confirm the validity of the proposed method. It is shown that the proposed turn fault detection scheme is simple and is capable of providing reliable fault detection that is immune to the motor nonidealities.

228 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a set of improved approximate models for the prediction of iron loss in permanent magnet motors, which can be used in design optimization programs and, since they are directly related to machine dimensions and material properties, provide quick insight into the effects of design changes.
Abstract: Permanent-magnet (PM) motors offer potential energy savings as compared with induction motors because of the virtual elimination of rotor loss and the reduction of stator loss from operation near unity power factor. In PM machines, iron losses form a significant fraction of the total loss partly due to the nonsinusoidal flux density distribution. Design optimization therefore requires good means of predicting these iron losses. Finite-element analysis can be employed but this approach is cumbersome and costly when used in the many iterations needed in optimizing the design. This paper presents a set of improved approximate models for the prediction of iron loss. They can be used in design optimization programs and, since they are directly related to machine dimensions and material properties, they also provide quick insight into the effects of design changes. A time-stepped finite-element method is employed to evaluate the iron losses in a range of typical PM machines and the results are used to evaluate the adequacy of the models. The predictions of overall iron losses are then compared with measurements made on two PM motors.

212 citations


Journal ArticleDOI
TL;DR: In this paper, the authors present a controller that directly regulates the active and instantaneous reactive power in a synchronous three-phase boost-type rectifier, which ensures a good regulation of the output voltage, and guarantees the power factor close to one.
Abstract: In this paper, the authors present a controller that directly regulates the active and instantaneous reactive power in a synchronous three-phase boost-type rectifier. The controller ensures a good regulation of the output voltage, and guarantees the power factor close to one. The controller builds upon the ideas of the well known direct torque control (DTC) for induction motors. In their case, the active and reactive powers replace the torque and flux amplitude used as the controlled outputs in DTC, thus motivating the name DPC-control. They show that a simple modification to the original algorithm makes the selection of the control inputs more accurate. To formalize this technique, they utilize the concept of output regulation subspaces. A modification is added to the basic controller to deal with disturbances such as unbalance and distortion in the source voltage. Finally, the proposed controller was tested both in simulations and experimentally, and illustrative results are presented.

204 citations


Proceedings ArticleDOI
01 Jun 2003
TL;DR: A modular Simulink implementation of an induction machine model is described in a step-by-step approach, where each block solves one of the model equations; therefore, unlike black box models, all of the machine parameters are accessible for control and verification purposes.
Abstract: In this paper, a modular Simulink implementation of an induction machine model is described in a step-by-step approach. With the modular system, each block solves one of the model equations; therefore, unlike black box models, all of the machine parameters are accessible for control and verification purposes. After the implementation, examples are given with the model used in different drive applications, such as open-loop constant V/Hz control and indirect vector control are given. Finally, the use of the model as an Induction generator is demonstrated.

196 citations


Reference BookDOI
01 Sep 2003
TL;DR: The TMSLF2407 DSP Controller C2xx DSP CPU and Instruction Set General Purpose Input/Output (GPIO) Functionality Interrupts on the TMS320LF 2407 The Analog-to-Digital Converter (ADC) The Event Managers (EVA, EVB) DSP-Based Implementation of DC-DC Buck-Boost Converters DSP based Control of Stepper Motors DSP baseD Control of Permanent Magnet Brushless DC Machines Park and Clarke's Transformations Space Vector Pulse Width Modulation DSPbased Vector Control of Ind
Abstract: Introduction to the TMSLF2407 DSP Controller C2xx DSP CPU and Instruction Set General Purpose Input/Output (GPIO) Functionality Interrupts on the TMS320LF2407 The Analog-to-Digital Converter (ADC) The Event Managers (EVA, EVB) DSP-Based Implementation of DC-DC Buck-Boost Converters DSP-Based Control of Stepper Motors DSP-BaseD Control of Permanent Magnet Brushless DC Machines Park and Clarke's Transformations Space Vector Pulse Width Modulation DSP-Based Control of Permanent Magnet Synchronous Machines DSP-Based Vector Control of Induction Motors DSP-Based Control of Switched Reluctance Motor Drives DSP-Based Control of Matrix Converters Appendix A: Induction Motor Simulation and Control using Software Packages

195 citations


Journal ArticleDOI
12 Oct 2003
TL;DR: In this article, flux barriers are asymmetrically designed so that the relative positions between the outer edges of the flux barriers and the teeth do not correspond, and torque ripple can be reduced dramatically.
Abstract: An interior permanent-magnet synchronous motor (IPMSM) is a highly efficient motor and operates in a wide speed range; therefore, it is used in many industrial and home appliance applications. However, the torque ripple of synchronous motors such as the IPMSM and synchronous reluctance motor is very large. The variation of magnetic resistance between the flux barriers and teeth causes the torque ripple. In this paper, flux barriers are asymmetrically designed so that the relative positions between the outer edges of the flux barriers and the teeth do not correspond. As a result, torque ripple can be reduced dramatically.

191 citations


Journal ArticleDOI
TL;DR: The key characteristics of the proposed WPD method are its ability to provide feature representations of multiple frequency resolutions for faulty modes, ability to clearly differentiate between healthy and faulty conditions, and its applicability to nonstationary signals.
Abstract: This paper presents a novel approach to induction motor current signature analysis based on wavelet packet decomposition (WPD) of the stator current. The novelty of the proposed method lies in the fact that by using WPD method the inherent nonstationary nature of stator current can be accurately considered. The key characteristics of the proposed method are its ability to provide feature representations of multiple frequency resolutions for faulty modes, ability to clearly differentiate between healthy and faulty conditions, and its applicability to nonstationary signals. Successful implementation of the system for two types of faults, i.e., rotor bar breakage and air-gap eccentricity is demonstrated here. The results are validated based on both simulation and experiments of a 5-hp induction motor.

190 citations


Journal ArticleDOI
TL;DR: In this paper, the authors proposed a fuzzy approach based on the stator current Concordia patterns, which can be used for accurate stator fault diagnosis if the input data are processed in an advantageous way, which is the case of the Concordia pattern.
Abstract: This paper deals with the problem of detection and diagnosis of induction motor faults. Using the fuzzy logic strategy, a better understanding of heuristics underlying the motor faults detection and diagnosis process can be achieved. The proposed fuzzy approach is based on the stator current Concordia patterns. Induction motor stator currents are measured, recorded, and used for Concordia patterns computation under different operating conditions, particularly for different load levels. Experimental results are presented in terms of accuracy in the detection of motor faults and knowledge extraction feasibility. The preliminary results show that the proposed fuzzy approach can be used for accurate stator fault diagnosis if the input data are processed in an advantageous way, which is the case of the Concordia patterns.

179 citations


Journal ArticleDOI
12 Oct 2003
TL;DR: In this paper, the amplitude, phase and frequency of a single sinusoid embedded in a nonstationary waveform is extracted for motor current signature analysis of induction machines operating during transients and the residual current is then analyzed using wavelets for the detection of broken rotor bars.
Abstract: A new algorithm is introduced for motor current signature analysis of induction machines operating during transients. The algorithm is able to extract the amplitude, phase and frequency of a single sinusoid embedded in a nonstationary waveform. The algorithm is applied to the detection of broken rotor bars in induction machines during startup transients. The fundamental component of current, which varies in amplitude, phase, and frequency, is extracted using the algorithm. The residual current is then analyzed using wavelets for the detection of broken rotor bars. This method of condition monitoring does not require parameters such as speed or number of rotor bars, is not load dependent and can be applied to motors that operate continuously in the transient mode, e.g., wind generators or motor-operated valves.

178 citations


Journal ArticleDOI
TL;DR: In this article, a parallel stator resistance and rotor speed identification algorithm is developed for the rotor flux-based model reference adaptive system (MRAS) type of the speed estimator in conjunction with a rotor flux oriented control scheme.
Abstract: Accurate knowledge of stator resistance is of utmost importance for correct operation of a number of speed sensorless induction motor control schemes in the low speed region. Since stator resistance inevitably varies with operating conditions, stable and accurate operation at near-zero speed requires an appropriate online identification algorithm for the stator resistance. The paper proposes such an identification algorithm, which is developed for the rotor flux-based model reference adaptive system (MRAS) type of the speed estimator in conjunction with a rotor flux oriented control scheme. In this speed estimation method, only one degree of freedom (out of the two available) is utilized for speed estimation. It is proposed to utilize the second available degree of freedom as a means for adapting the stator resistance online. The parallel stator resistance and rotor speed identification algorithm is developed in a systematic manner, using Popov's hyperstability theory. It increases the complexity of the overall control system insignificantly and enables correct speed estimation and stable drive operation at near-zero speeds. The proposed speed estimator with parallel stator resistance identification is at first verified by simulation. Extensive experimentation is conducted next at low speeds of rotation and successful stator resistance identification is achieved down to 0.5-Hz frequency of rotation.

174 citations


Book
21 May 2003
TL;DR: In this article, a Dual-Axis Linear Stepper (Sawyer) motors with feedback linearization was used to model and control a class of nonlinear systems, including brushless DC motors and induction motors.
Abstract: 1 Introduction.- 2 Dual-Axis Linear Stepper (Sawyer) Motors.- 3 Modeling of Stepper Motors.- 4 Stepping.- 5 Feedback Linearization and Application to Electric Motors.- 6 Robust Adaptive Control of a Class of Nonlinear Systems.- 7 Robust Adaptive Control of Stepper Motors.- 8 Current Control of Stepper Motors Using Position Measurements Only.- 9 Voltage Control of Stepper Motors Using Position and VelocityMeasurements.- 10 Voltage Control of PM Stepper Motors Using Position Measurement Only.- 11 Brushless DC Motors.- 12 Induction Motor: Modeling and Control.- 13 Adaptive Control of Induction Motors.- 14 Passivity-Based Control of Electric Motors.- 15 Torque Ripple Reduction for Step Motors.- 16 Friction Compensation in Servo-Drives.- A Fundamentals of AC Machines.- B.1 Case of Position-Only Dependent Transformations.- C Torque Maximization with Current and Voltage Constraints (Field Weakening).- C.1 Low-Speed Range.- C.2 High-Speed Range.- C.3 Intermediate-Speed Range.- C.4 Transition Speeds.- D Stable System Inversion.- E Lyapunov Stability Theorems.- F Backstepping.- G Input-to-State Stability and Nonlinear Small Gain.

Journal ArticleDOI
TL;DR: In this article, the amplitude, shape, phase, and number of pulses per cycle were measured using a digital instrumentation that can measure the amplitude and shape of the pulses in an induction motor and a hydrogenerator.
Abstract: The authors have developed digital instrumentation that can measure the amplitude, shape, phase, and number of pulses per cycle. Examples are given of results obtained from an induction motor, a hydrogenerator, a polymeric cable system with a defective joint, and a high-voltage current transformer.

Journal ArticleDOI
12 Oct 2003
TL;DR: In this paper, the authors proposed two different approaches for the diagnosis of stator faults in direct torque control (DTC) induction motor drives, based on motor current spectrum analysis and multiple reference frames theory.
Abstract: This paper addresses the subject of stator fault diagnosis in direct torque control (DTC) induction motor drives. The particularities of the behavior of a DTC drive, when in the presence of inter-turn short circuits, are exploited, thus allowing the proposal of two different approaches for the diagnosis of this type of fault. One of the proposed diagnostic techniques is the well known motor current spectrum analysis. It is demonstrated that in a DTC induction motor drive, with stator inter-turn short circuits, the action of the torque and flux controllers introduce a strong third harmonic in the motor supply currents, which can be used to detect this type of fault. The other diagnostic technique is based on the multiple reference frames theory, recently proposed by the authors for the diagnosis of stator faults in line-connected motors. Here, its use is exploited in the diagnosis of stator faults in DTC induction motor drives. Simulation and experimental results demonstrate the effectiveness of the two proposed techniques for the diagnosis of stator faults but emphasize the fact that the multiple reference frames technique is the preferred one when the residual asymmetries of the motor are not negligible.

Journal ArticleDOI
TL;DR: In this paper, two simple and very useful techniques for the efficiency optimization of the indirect vector-controlled induction motor drives are presented for the synchronously rotating reference frame the flux-producing current is controlled until the power at the DC link is minimum.
Abstract: This paper presents two simple and very useful techniques for the efficiency optimization of the indirect vector-controlled induction motor drives. In the synchronously rotating reference frame the flux-producing current is controlled until the power at the DC link is minimum. Of the two techniques, the first method controls the flux-producing current in a regular and smooth manner. The second technique combines loss model and search approaches in a unique way to propose a hybrid method, where the first estimate is from the loss model approach and the subsequent adjustment of the flux is through the search technique. Both the algorithms are simple, easily realizable, and offer fast convergence. Also, smooth control of the flux offers excellent dynamic performance. A comparative assessment shows that the hybrid method is the best, even if an approximate equivalent circuit for the induction motor is used for the analysis and optimization of the losses. The close agreement between the simulation and the experimental results confirms the validity and usefulness of the proposed techniques.

Journal ArticleDOI
TL;DR: By using triangular carrier wave and proper modulating waves for each inverter, the open-end winding induction motor can be operated in the entire modulation range, eliminating all the 6n /spl plusmn/ 1 harmonics coupled with 11th and 13th harmonic suppression.
Abstract: In this paper, a harmonic elimination and suppression scheme for a dual-inverter-fed open-end winding induction motor drive is presented. Two isolated dc-link sources with voltage ratio of approximately 1 : 0.366 are required for the present drive. These two isolated do links feeding two inverters to drive the open-end winding induction motor eliminate the triplen harmonic currents from the motor phase. The pulsewidth-modulation scheme proposed enables the cancellation of all the 5th- and 7th-order (6n /spl plusmn/ 1, where n = 1, 3, 5, 7, etc.) harmonic voltages and suppresses the 11th- and 13th-order harmonic voltage amplitudes in the motor phase voltage, in all modulation ranges. The next higher order harmonics present in the motor phase voltages are 23rd, 25th, 35th, 37th etc. (6n /spl plusmn/ 1, n = 4, 6, etc.). By using triangular carrier wave and proper modulating waves for each inverter, the open-end winding induction motor can be operated in the entire modulation range, eliminating all the 6n /spl plusmn/ 1 harmonics (n = 1, 3, 5, 7, etc.) coupled with 11th and 13th harmonic suppression. The proposed scheme also gives a smooth transition to the overmodulation region.

Journal ArticleDOI
TL;DR: It is concluded that neural detectors for rotor and stator faults as well as for rolling bearings and supply asymmetry faults can be developed based on measurement data acquired on-line in the drive system.

Journal ArticleDOI
TL;DR: Investigations were carried out on a novel direct torque control system, which not only reduces the undesirable torque ripple by up to 98% by means of introducing a modulation between the selected active state and a zero state, but also maintains constant switching frequency.
Abstract: Investigations were carried out on a novel direct torque control system, which not only reduces the undesirable torque ripple by up to 98% by means of introducing a modulation between the selected active state and a zero state, but also maintains constant switching frequency. Additionally, this two-state modulator is fuzzy adaptive and may be applied to any induction motor. Simulation and the results of experiment illustrate the operation and performance of the proposed fuzzy-logic-based controller.

DOI
01 Jan 2003
TL;DR: The EM Diagnostics Ltd, based in Alford, Aberdeenshire, Scotland, has been operating since 2001 as discussed by the authors, with a focus on condition monitoring of electrical drives.
Abstract: Director and Consultant with EM Diagnostics Ltd., in Alford, Aberdeenshire, Scotland, since August 2001. He has 42 years’ experience covering the installation, maintenance, design, performance, and condition monitoring of electrical drives. Professor Thomson has worked as electrician, R&D engineer, academic, and consultant. In 1990, he was appointed Professor at Robert Gordon University in Aberdeen, Scotland, for his research and development work on condition monitoring for electrical drives. He was awarded a First Class Technological Certificate in Electrical Installation work from The City & Guilds London Institute (1966), and a Higher National Certificate in Electrical Engineering (1970) Professor Thomson has a BSc (Hons, Electrical Engineering, 1973) and an MSc (1977) from the University of Strathclyde, Scotland. He is a SMIEEE and FIEE, a CEng in the UK, a visiting Professor in Electrical Engineering at the University of Abertay, Scotland, and has published over 70 papers.

Proceedings ArticleDOI
08 Dec 2003
TL;DR: The differential evolution algorithm is applied to parameter identification of two induction motors used in the house circulation pumps produced by the Danish pump manufacturer Grundfos A/S and outperformed the previously best known algorithms on both problems.
Abstract: Parameter identification of system models is a fundamental step in the process of designing a controller for a system. In control engineering, a wide selection of analytic identification techniques exists for linear systems, but not for nonlinear systems. Instead, the model parameters may be determined by an optimization algorithm by minimizing the error between model output and measured data. We apply the differential evolution algorithm to parameter identification of two induction motors. The motors are used in the house circulation pumps produced by the Danish pump manufacturer Grundfos A/S. The experiments presented use differential evolution, and is a follow-up study of an comparison of eight stochastic search algorithms on the two motor identification problems. In conclusion, the differential evolution algorithm outperformed the previously best known algorithms on both problems.

Journal ArticleDOI
TL;DR: In order to eliminate the drift problems, the pure integrator of the voltage model is replaced with a first-order low-pass filter, and the error due to this replacement is compensated in a very simple way.
Abstract: This letter deals with voltage model flux estimators for sensorless induction motor drives. In order to eliminate the drift problems, the pure integrator of the voltage model is replaced with a first-order low-pass filter, and the error due to this replacement is compensated in a very simple way.

Proceedings ArticleDOI
02 Nov 2003
TL;DR: The effect of the motor characteristics on the vehicle performance is analyzed, and the characteristics of three major electric motors-induction motor, permanent magnet brushless DC motor and switched reluctance motor are investigated.
Abstract: The ideal characteristics of an electric motor drive for traction application in an electric and hybrid electric vehicle are high torque at low speed region for fast acceleration, hill climbing and obstacle negotiation, and low torque at high speed for normal driving. To minimize the power rating of the motor drive, therefore, the energy storage power rating, at the given vehicle performance, the electric motor drive is required to have a long constant power range to meet the torque and speed demand. In this paper, the effect of the motor characteristics on the vehicle performance is analyzed, and the characteristics of three major electric motors-induction motor, permanent magnet brushless DC motor and switched reluctance motor are investigated.

Journal ArticleDOI
TL;DR: In this paper, a new detection method based on wavelet ridge is presented for the detection of cage motor broken rotor bars, aiming at the motor's starting period during which the motor accelerates progressively and CFCFR approaches the power frequency gradually in frequency spectrum.
Abstract: Detection of cage motor broken rotor bars has long been an important but difficult job in the detection area of motor faults. The characteristic frequency component of faulted rotor (CFCFR) is very close to the power frequency component but by far less in amplitude, which brings about great difficulty for accurate detection. A new detection method based on wavelet ridge is presented in this paper. Aiming at the motor's starting period during which the motor accelerates progressively and CFCFR approaches the power frequency gradually in frequency spectrum, the wavelet ridge-based method is adopted to analyze this transient procedure and the CFCFR is extracted. The influence of power frequency can be effectively eliminated, and detection accuracy can be greatly improved by using the approach presented in this paper. Also, this is indeed a novel but excellent approach for the detection domain of cage induction motor broken rotor bars.

Journal ArticleDOI
12 Oct 2003
TL;DR: In this paper, a comparison of the measurement procedures defined by these International Standards is reported, together with some comments to the prescribed methodologies, based on experimental results obtained by testing four general purpose three-phase induction motors.
Abstract: The motor efficiency has to be measured or calculated in accordance to International Standards. The most important world references are the IEEE 112-B, the IEC 34-2 and the JEC 37 Standards. In this paper, a comparison of the measurement procedures defined by these International Standards is reported, together with some comments to the prescribed methodologies. The comparison is based on experimental results obtained by testing four general purpose three-phase induction motors. The stray-load loss measurement represents a critical key for the correct evaluation of the motor efficiency. For this reason, a critical analysis of this type of losses has been performed. In particular, the stray-load loss sensitivity to the measurement errors is analyzed in order to understand which are the most critical quantities that influence their evaluation. In the final part of the paper the temperature influence on the conventional iron losses is experimentally analyzed. The performed tests show that the temperature difference between the no-load test and the motor real operative conditions is not negligible.

Proceedings ArticleDOI
12 Oct 2003
TL;DR: A new flux switching motor and drive offering high power density and an extremely low cost power electronic controller that delivers electronic commutation, high dynamic performance, speed and torque control at anextremely low cost.
Abstract: This paper presents the results of a new flux switching motor and drive offering high power density and an extremely low cost power electronic controller. The motor contains a DC field winding and a bifilar armature winding, both on the stator with a simple and rugged salient pole reluctance rotor. The power electronic controller requires only two ground referenced power transistors. This delivers electronic commutation, high dynamic performance, speed and torque control at an extremely low cost. The design of the motor and its electronic controller is described and test results of a complete drive delivering 2 kW at 15000 r/min are presented.

Journal ArticleDOI
TL;DR: The high performance of Elman's RNN was shown by means of two different applications: detecting anomalies introduced from the simulated power operation of a high-temperature gas cooled nuclear reactor and detecting motor bearing damage using a coherence function approach for induction motors.

Journal ArticleDOI
12 Oct 2003
TL;DR: In this paper, the authors investigated the effect of slot permeance on the production of principal slot harmonics (RSH) in three-phase and single-phase induction motors.
Abstract: Three-phase as well as single-phase induction machines form the backbone of a substantial portion of the adjustable-speed drives' applications. Among the current estimation techniques available for speed-sensorless induction motor drives, speed measurement based on rotor or principal slot harmonics (RSH or PSH) detection in machine line current happens to be a prominent one. In practice, two predominant RSH can be seen. The present paper attempts to investigate the effect of slot permeance on the production of RSH. Simulation studies on a small motor but with a popular stator, rotor slot, and pole combination suggest that their effect is less significant compared to rotor space harmonics effect. Also, out of the two aforementioned RSH, the cause of the less significant slot harmonic is shown to be the negative-sequence-current-induced reverse rotating field. Voltage unbalances and constructional imperfections can cause negative-sequence current even in a healthy machine. Thus, although the less significant RSH is absent in the simulated line current of an idealized machine running from a balanced supply, it can be detected in an actual machine.

Dissertation
01 Jan 2003
TL;DR: In this paper, the authors focus on the design and analysis of the control system structure for back-to-back converter squirrel-cage induction machine drives, where the back electromotive force is used as the basis for sensorless control.
Abstract: This thesis focuses on design and analysis of the control system structure for back-to-back converter squirrel-cage induction machine drives. Particularly, sensorless control of induction machines, meaning vector control without a mechanical shaft sensor, and vector control of pulsewidth-modulated (PWM) rectifiers are considered. The back electromotive force is used as the basis for sensorless control in this thesis. A variant of the classical "voltage model" is adopted for sensorless flux estimation. It is shown that the estimator must be redesigned for the purpose of arbitrarily placement of the closed-loop poles. A thorough stability analysis of the redesigned estimator shows that asymptotical stability can be guaranteed at nominal speeds. The stability at very low frequencies is, however, largely affected by the knowledge of the stator resistance. The presence of a singularity for zero stator frequency is found, which makes it impossible to guarantee stable operation at very low frequencies, except for the case of zero external load torque. The underlying mechanisms behind the two widely acknowledged instability phenomena for sensorless control at low frequencies are revealed. The most critical form of instability is the infamous flux collapse: the flux collapses to approximately zero, giving nearly total loss of torque, and uncontrolled rotation in the direction of the external load torque. The less well-known instability phenomenon frequency lockup is not as critical: the field orientation deteriorates, such that the torque reduces but not vanish, and the stator frequency and rotor speed lock on to constant values close to zero. A control system structure is developed for the PWM rectifier. The previously proposed concept of virtual flux is adopted for grid-voltage synchronization, and three different synchronization algorithms are analyzed. The PWM rectifier is also considered for an active filtering application, for which a vector current control system designed for the deadbeat response is designed. An analysis shows that the resulting deadbeat control system is equivalent to previously proposed Smith predictor structures.

Journal ArticleDOI
TL;DR: In this paper, a hybrid fuzzy controller for direct torque control (DTC) induction motor drives is presented, which consists of proportional-integral (PI) control at steady state, PI-type fuzzy logic control at transient state, and a simple switching mechanism between steady and transient states.
Abstract: A new hybrid fuzzy controller for direct torque control (DTC) induction motor drives is presented in this paper. The newly developed hybrid fuzzy control law consists of proportional-integral (PI) control at steady state, PI-type fuzzy logic control at transient state, and a simple switching mechanism between steady and transient states, to achieve satisfied performance under steady and transient conditions. The features of the presented new hybrid fuzzy controller are highlighted by comparing the performance of various control approaches, including PI control, PI-type fuzzy logic control (FLC), proportional-derivative (PD) type FLC, and combination of PD-type FLC and I control, for DTC-based induction motor drives. The pros and cons of these controllers are demonstrated by intensive experimental results. It is shown that the presented induction motor drive is with fast tracking capability, less steady state error, and robust to load disturbance while not resorting to complicated control method or adaptive tuning mechanism. Experimental results derived from a test system are presented confirming the above-mentioned claims.

Proceedings ArticleDOI
01 Jun 2003
TL;DR: In this paper, the authors demonstrate through industrial case histories how current signature analysis can reliably diagnose rotor cage problems in induction motor drives and demonstrate the ability to separate current components resulting from gearbox dynamics and from those produced by broken rotor bars.
Abstract: This paper will demonstrate through industrial case histories how current signature analysis can reliably diagnose rotor cage problems in induction motor drives. Theoretical advancements have now made it possible to predict rotor disturbances due to gearbox dynamics and mechanical drive train characteristics thus making motor current signature analysis (MCSA) testing much more robust and reliable. Case histories will be presented which demonstrate the ability to separate current components resulting from gearbox dynamics and from those produced by broken rotor bars. From this data, a new handheld instrument for reliable detection of broken rotor bars, air gap eccentricity, shorted turns in LV stator windings, mechanical drive phenomena and certain mechanical problems in induction motor drives is being developed and will be described.

Journal ArticleDOI
K.-S. Lee1, J.-S. Ryu1
24 Jul 2003
TL;DR: In this paper, an instrument fault detection isolation scheme (IFDIS) for direct-torque-control-based induction motor drives is proposed, which consists of an adaptive gain scheduling observer as a residual generator and a special sequential test logic unit.
Abstract: The effects of instrument faults in direct-torque-control-based induction motor drives are analysed and an instrument fault detection isolation scheme (IFDIS) for the drives is proposed. The IFDIS detects and isolates the incipient fault(s) of a speed sensor and current sensors in real-time. The scheme consists of an adaptive gain scheduling observer as a residual generator and a special sequential test logic unit. Although the IFDIS is a single observer scheme, it has the function of fault isolation that normally only a multiple-estimator-based IFDIS possesses. Simulation results show the detection and isolation performance of the IFDIS and the applicability of the scheme to fault tolerant control system design.