EPE Association: EPE 2005 - Topic 09-5b - DS: Induction machines, Switched reluctance, Linear machines

EPE 2005 - Topic 09-5b - DS: Induction machines, Switched reluctance, Linear machines
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 09: ELECTRICAL MACHINES > EPE 2005 - Topic 09-5b - DS: Induction machines, Switched reluctance, Linear machines

   [return to parent folder]

   A New Sensoless Control for Switched Reluctance Motor
By MIKI Ichiro; YOSHIDA Kazumasa; KOMATSUZAKI Akitomo [View]
[Download]

Abstract: This paper describes a new rotor position sensorless control method for switched reluctance motor (SRM) drives based on the variation of an active phase inductance. The phase inductance regularly varies with the rotor position and increases as the rotor and stator poles are approaching alignment. When the rotor and stator poles are aligned, the phase inductance has a maximum value, and thereafter the phase inductance decreases. In the low speed region, the SRM can be controlled without the position sensor by changing the excitation when the slope of the phase inductance becomes zero or less than zero. As the speed increases, this method cannot be applied because of the large negative torque produced by the regenerative current. Therefore, the SRM must be controlled so that the current can be zero at the aligned position approximately. To implement smoothly this operation, the sensorless control method using the difference between the phase inductance at the aligned position and the phase inductance calculated every sampling is introduced. In the high speed region, a new technique with the difference of both phase inductances is successfully used. Experimental results present the validity of the proposed method.

   A Switched Reluctance Machine for High-Torque Low-Speed Applications
By BRUNO Ottorino; BOLOGNESI Paolo; TAPONECCO Lucio [View]
[Download]

Abstract: This paper presents a first overview of an unconventional switched-reluctance rotating machine conceived to provide high specific torque in low-speed applications by leveraging on the magnetic gearing effect while featuring a simple, modular, highly symmetrical structure that should permit to limit manufacturing costs. After recalling the main proposals found in the literature for similar targets, the first application considered for the machine is briefly described. The proposed structure is then introduced and briefly analyzed, highlighting the main features and issues related to manufacturing, performance and control. A few results coming from 3-D FEM analysis of the machine are finally reported and briefly commented.

   Analytical investigation of rotor slot harmonics in a three phase induction motor with broken rotor bars
By BOUCHERMA Mohamed; KAIKAA Mohamed Yazid; KHEZZAR Abdelmalek [View]
[Download]

Abstract: The present paper attempts to investigate the effect of space distribution of rotor bars in squirrel cage induction machine on the generation of the rotor slot harmonics (RSH). An analytical expression of the stator current describing the necessary relationship between rotor bar and pole pairs numbers required for the presence of RSH has been developed. The proposed expression is based on the linkage inductance expression derived using the winding function approach (WFA) and its decomposition into Fourier series. An important issue in such effort is to predict RSH in healthy machine as well as in machine with broken rotor bars.

   Characteristic of a Vector Controlled Induction Motor Drives with Electrical Double Layer Capacitor
By TADANO Yugo; YAMADA Tetsuo; NOMURA Masakatsu; MATSUSE Kouki; WATANABE Toshio; YAMASHITA Koichi [View]
[Download]

Abstract: This paper proposes a direct current (DC) power supply circuit consisted of a battery and an electrical double layer capacitor (EDLC). Inverter-fed induction motor (IM) drive is controlled using the proposed power supply circuit. This power supply circuit can be composed of a power regeneration system consisting of the battery connected to the EDLC through a step-up and down chopper. By switching control of the step-up and down chopper, it can control charge and discharge of the EDLC. Therefore, the EDLC enables us to achieve the giving and receiving of DC with the inverter. When the inverter-fed IM drive generates a power with regenerative braking, the power is charged to the EDLC. The EDLC discharges the charged power when the inverter-fed IM drive is accelerated or load is added to the inverter-fed IM. By means of these works, the proposed power supply circuit can reduce the load of battery. The utility of the proposed method is examined through computer simulations and experimental results.

   Detailed Study of the Rotor Asymmetry Effects of Induction Machine Under Different Supply Conditions
By LEBAROUD Abdesselam; CLERC Guy; BENTOUNSI Amar [View]
[Download]

Abstract: This paper presents a detailed study of the rotor asymmetry, caused by broken bars, and their effects on the stator current of an induction machine under different supply conditions. The analytical models dedicated to the rotor faults are often penalized by simplifying assumptions, particularly the distribution of the magnetic flux density in the air-gap. The important information is likely to be omitted partially or completely if one considers only the fundamental of the magnetic flux density. In this study a detailed analysis by finite element method (FEM) of two induction motors in both healthy and faulty cases were presented. Experimental tests corroborate with the simulation results.

   Diesel-Generator-Units Dynamic Analysis During the Start-Up of Induction Motors Drives
By MILKOVIC Mateo; MIROSEVIC Marija; MALJKOVIC Zlatko [View]
[Download]

Abstract: The paper analyses the dynamics of generator-units during start-up of the induction motor drives. A unique mathematical model of integral motor drives has been developed, consisting of: a diesel engine, a synchronous generator and two non-regulated motor drives fed directly from generator-unit terminals. The aim of this paper is to compare dynamics behaviours of the generator-units during starting the second induction motor at the moment when the instantaneous electromagnetic torque of the synchronous generator reached various values.

   Dynamic Reconfiguration of Direct Torque and Stator Flux Control by Means of Sliding Mode Theory
By LOUIS Jea; MONMASSON Eric; NAASSANI Ahmad Ammar [View]
[Download]

Abstract: This paper presents the synthesis of the direct torque and stator flux control strategies (DTSFC) by means of sliding mode theory. Two cases of voltage source inverter (VSI) control will be analyzed: a direct control (hysteresis VSI control) implying the use of a switching table, and an indirect control by means of SVM. Finally, these two methods of VSI control will be associated together in a new strategy called Dynamic Reconfiguration of VSI Control Algorithms. This association yields an excellent dynamic performances at transient state as a result of VSI direct control method and low chattering at steady-state due to the VSI indirect control strategy. To support the proposed synthesis of DTSFC algorithms, simulation and experimental tests are given throughout the paper.

   Electromagnetic analysis of the induction motor with spiral sheet rotor
By PERE; MUJA [View]
[Download]

Abstract: The study of the magnetic characteristics and constructive shapes of conductive materials, allows a better use of its electrical characteristics, reducing the maintenance and extending the life of the electrical machines. The improvements obtained on the torque with low currents using rotor with spiral sheets are analyzed on this paper. To have a complete study, several rotors and stators have been built to verify the electromagnetic variations on the three-phase asynchronous motors where they combine different constructive and mechanical characteristics of the related elements: changing inertias, constructive materials, and the geometrical shapes and disposition of the sheets. These different types of motors have been first tested in the laboratory, then, are simulated using computer aided tools (Matlab-Simulink). In particular four stators (1000 rpm, 1500rpm, 1500rpm-type A, and 3000 rpm) having the same constructive parameters, have been tested with the following rotors: solid rotor, solid rotor with diamagnetic rings, drag cup, and simple and double squirrel cage rotor. All these results have been compared to those obtained with the seven variants of spiral sheet rotor, presented on this paper. It has been demonstrated that it is possible to considerably reduce the starting currents, and therefore reducing the maintenance and extending the life of motors, without any negative consequence on the starting torque.

   Electronic stabilization methods for switched reluctance drives in weak supply nets
By GERLING Dieter; SCHRAMM Andreas [View]
[Download]

Abstract: Smooth operation of reluctance machines concerning torque ripple and acoustic noise requires overlapping current flow in subsequent phases. In weak supply nets this may cause deep voltage drops resulting in critical states, e.g. for the microelectronic devices. This paper presents three electronic measures suitable for avoiding those deep voltage drops.

   Finite Element Analysis of A Novel Centrifugal Induction Blood Pump
By TSENG King J.; WU Peng [View]
[Download]

Abstract: Axial-gap motors have flat profiles which make them suitable for use as wheel motors for electric vehicles or as shaft-less centrifugal pumps. In this paper, we present the investigation of an induction type of axial-gap motor using three-dimensional time-stepping finite element analysis. Unlike conventional radial-gap motor with circular cross-section throughout a relatively long axial length, axial-gap motors are not so suitable to be investigated by two-dimensional finite element analysis. Three-dimensional finite element analysis represents a higher order of technology, which has only now beginning to reach maturity. Time-stepping version of three-dimensional finite element software is now available, and we have applied it to study the characteristics of a dual stator large air gap axial flux induction motor and to optimize its rotor design.

   High-Performance Motion Control of Linear Motor Drives
By BEINEKE Stephan [View]
[Download]

Abstract: This paper presents a high-performance linear drive control featuring encoder signal correction, oscil-lation damping and an advanced feedforward control for friction, speed and acceleration to reduce the dynamic trajectory errors. These measures and tools aiming at control optimization are investigated concerning their performance and benefits with linear drive systems. Major costs can be reduced by using magneto-resistive or hall effect based sensors. Different methods for determing the commutation angle allow to replace the absolute position encoders by incremental encoders. Specific analysis and commissioning tools allow an easy handling of the advanced features.

   IMPROVING EFFICIENCY IN SWITCHED RELUCTANCE MOTOR DRIVE WITH ON LINE CONTROL OF TURN-ON AND TURN-OFF ANGLES
By TORRENT Marcel; BLANQUE Baldui; ANDRADA Pere; PERAT Jose Ignacio [View]
[Download]

Abstract: A current controlled switched reluctance motor drive for variable speed applications with efficiency optimisation is presented. Firing angles are computed online, the turn-on is calculated by means of the rule of Bose, and the turn-off is calculated using the general theory of the optimal turn-off angle proposed by Gribble. In steady state operation, the initial selection of firing angles is fine-tuned by means of an algorithm that minimizes the input power of the drive. A 6/4 switched reluctance motor drive prototype was tested and the experimental results show an improvement in online efficiency, a good steady-state performance and no deterioration in the dynamic response. An efficiency comparison with a commercial vector-controlled induction motor drive of the same size is also included.

   Method for Measuring Torques of Induction Motors for the Slip ranging from 0 to 2 by Detecting Twists of Stator
By TAKANO Hiroo [View]
[Download]

Abstract: There is a negative torque at some slip when the locus of a rotating magnetic field is ellipse in a two-phase induction motor. A method for measuring the torque including the negative value continuously for the slip ranging from 0 to 2 is required for evaluating the trial motors and improving them, but there are few papers on this subject. In this paper the method for resolving this subject is proposed. It is based on the principle that the torque generated from the stator and the restoring torque from the springs of the sensors are balanced, and the twists of the stator which are proportional to the torques are transmitted to the sensors.In addition, a new method for determining the forward-field torque and backward-field torque separately are presented. They are obtained by detecting the fluxes linking with the closed circuit on the rotor, and by substituting the fluxes, resistance and reactance for the formulas. These calculated values agree well with the measured values for the forward-field torque vs. slip characteristics of the motor having the circular rotating magnetic field. Same result is obtained for the backward-field torque. Comparing two type of motors having the wound-rotor and the cast squirrel-cage rotor, it is clear that the ratio of the reactance to the resistance is the key factor to obtain the torque versus slip characteristics which a customer requires.

   Online Winding Temperature Monitoring of PWM Inverter-Fed Induction Machines
By PLOTKIN Yuriy; STIEBLER Manfred [View]
[Download]

Abstract: A method for online winding temperature monitoring of PWM inverter-fed induction machines by injecting a d.c. bias into the stator voltage and using the resistance method is proposed. Advantageously no external devices are required for this method.

   POST-FAULT PERFORMANCE OF A FAULT TOLERANT SWITCHED RELUCTANCE MOTOR DRIVE
By MARTINEZ Eusebi; ANDRADA Pere; SANCHEZ Jose Antonio; BLANQUE Baldui; PERAT Jose Ignacio; TORRENT Marcel [View]
[Download]

Abstract: A current controlled switched reluctance motor drive for variable speed applications with efficiency optimisation is presented. Firing angles are computed online, the turn-on is calculated by means of the rule of Bose, and the turn-off is calculated using the general theory of the optimal turn-off angle proposed by Gribble. In steady state operation, the initial selection of firing angles is fine-tuned by means of an algorithm that minimizes the input power of the drive. A 6/4 switched reluctance motor drive prototype was tested and the experimental results show an improvement in online efficiency, a good steady-state performance and no deterioration in the dynamic response. An efficiency comparison with a commercial vector-controlled induction motor drive of the same size is also included.

   Stability Analysis of a BDFM under Open-Loop Voltage Control
By ROYE Daniel; SARASOLA Izaskun; POZA Javier; OYARBIDE Estanis [View]
[Download]

Abstract: This paper presents a stability analysis of the Brushless Doubly-Fed Machine (BDFM) under Open-Loop Voltage Control (OLVC). For this purpose a new small signal model has been developed. This new model takes into account the dynamic characteristics of the load. This study is validated in a experimental machine prototype.

   TRANSIENT ANALYSIS OF PERMANENT MAGNET LINEAR SYNCHRONOUS MOTORS
By GENTILE Giuseppe; ROTONDALE Nicola; OMETTO Antonio [View]
[Download]

Abstract: A modified one-dimensional mathematical model based on the space-vectors theory is used to analyse the performance of permanent magnet linear synchronous motors with starting and dumping sheet. The end-effects are taken into account by assuming that the length of the iron core is infinite and the length of the armature winding is finite. The resulting differential equation set allows both steady state and transient operations to be analysed. The model is used to analyse the transient performance (starting and load step) of two low power motors.

EPE 2005 - Topic 09-5b - DS: Induction machines, Switched reluctance, Linear machines
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2005 - Conference > EPE 2005 - Topic 09: ELECTRICAL MACHINES > EPE 2005 - Topic 09-5b - DS: Induction machines, Switched reluctance, Linear machines
	[return to parent folder]

	A New Sensoless Control for Switched Reluctance Motor By MIKI Ichiro; YOSHIDA Kazumasa; KOMATSUZAKI Akitomo	[View] [Download]
Abstract: This paper describes a new rotor position sensorless control method for switched reluctance motor (SRM) drives based on the variation of an active phase inductance. The phase inductance regularly varies with the rotor position and increases as the rotor and stator poles are approaching alignment. When the rotor and stator poles are aligned, the phase inductance has a maximum value, and thereafter the phase inductance decreases. In the low speed region, the SRM can be controlled without the position sensor by changing the excitation when the slope of the phase inductance becomes zero or less than zero. As the speed increases, this method cannot be applied because of the large negative torque produced by the regenerative current. Therefore, the SRM must be controlled so that the current can be zero at the aligned position approximately. To implement smoothly this operation, the sensorless control method using the difference between the phase inductance at the aligned position and the phase inductance calculated every sampling is introduced. In the high speed region, a new technique with the difference of both phase inductances is successfully used. Experimental results present the validity of the proposed method.

	A Switched Reluctance Machine for High-Torque Low-Speed Applications By BRUNO Ottorino; BOLOGNESI Paolo; TAPONECCO Lucio	[View] [Download]
Abstract: This paper presents a first overview of an unconventional switched-reluctance rotating machine conceived to provide high specific torque in low-speed applications by leveraging on the magnetic gearing effect while featuring a simple, modular, highly symmetrical structure that should permit to limit manufacturing costs. After recalling the main proposals found in the literature for similar targets, the first application considered for the machine is briefly described. The proposed structure is then introduced and briefly analyzed, highlighting the main features and issues related to manufacturing, performance and control. A few results coming from 3-D FEM analysis of the machine are finally reported and briefly commented.

	Analytical investigation of rotor slot harmonics in a three phase induction motor with broken rotor bars By BOUCHERMA Mohamed; KAIKAA Mohamed Yazid; KHEZZAR Abdelmalek	[View] [Download]
Abstract: The present paper attempts to investigate the effect of space distribution of rotor bars in squirrel cage induction machine on the generation of the rotor slot harmonics (RSH). An analytical expression of the stator current describing the necessary relationship between rotor bar and pole pairs numbers required for the presence of RSH has been developed. The proposed expression is based on the linkage inductance expression derived using the winding function approach (WFA) and its decomposition into Fourier series. An important issue in such effort is to predict RSH in healthy machine as well as in machine with broken rotor bars.

	Characteristic of a Vector Controlled Induction Motor Drives with Electrical Double Layer Capacitor By TADANO Yugo; YAMADA Tetsuo; NOMURA Masakatsu; MATSUSE Kouki; WATANABE Toshio; YAMASHITA Koichi	[View] [Download]
Abstract: This paper proposes a direct current (DC) power supply circuit consisted of a battery and an electrical double layer capacitor (EDLC). Inverter-fed induction motor (IM) drive is controlled using the proposed power supply circuit. This power supply circuit can be composed of a power regeneration system consisting of the battery connected to the EDLC through a step-up and down chopper. By switching control of the step-up and down chopper, it can control charge and discharge of the EDLC. Therefore, the EDLC enables us to achieve the giving and receiving of DC with the inverter. When the inverter-fed IM drive generates a power with regenerative braking, the power is charged to the EDLC. The EDLC discharges the charged power when the inverter-fed IM drive is accelerated or load is added to the inverter-fed IM. By means of these works, the proposed power supply circuit can reduce the load of battery. The utility of the proposed method is examined through computer simulations and experimental results.

	Detailed Study of the Rotor Asymmetry Effects of Induction Machine Under Different Supply Conditions By LEBAROUD Abdesselam; CLERC Guy; BENTOUNSI Amar	[View] [Download]
Abstract: This paper presents a detailed study of the rotor asymmetry, caused by broken bars, and their effects on the stator current of an induction machine under different supply conditions. The analytical models dedicated to the rotor faults are often penalized by simplifying assumptions, particularly the distribution of the magnetic flux density in the air-gap. The important information is likely to be omitted partially or completely if one considers only the fundamental of the magnetic flux density. In this study a detailed analysis by finite element method (FEM) of two induction motors in both healthy and faulty cases were presented. Experimental tests corroborate with the simulation results.

	Diesel-Generator-Units Dynamic Analysis During the Start-Up of Induction Motors Drives By MILKOVIC Mateo; MIROSEVIC Marija; MALJKOVIC Zlatko	[View] [Download]
Abstract: The paper analyses the dynamics of generator-units during start-up of the induction motor drives. A unique mathematical model of integral motor drives has been developed, consisting of: a diesel engine, a synchronous generator and two non-regulated motor drives fed directly from generator-unit terminals. The aim of this paper is to compare dynamics behaviours of the generator-units during starting the second induction motor at the moment when the instantaneous electromagnetic torque of the synchronous generator reached various values.

	Dynamic Reconfiguration of Direct Torque and Stator Flux Control by Means of Sliding Mode Theory By LOUIS Jea; MONMASSON Eric; NAASSANI Ahmad Ammar	[View] [Download]
Abstract: This paper presents the synthesis of the direct torque and stator flux control strategies (DTSFC) by means of sliding mode theory. Two cases of voltage source inverter (VSI) control will be analyzed: a direct control (hysteresis VSI control) implying the use of a switching table, and an indirect control by means of SVM. Finally, these two methods of VSI control will be associated together in a new strategy called Dynamic Reconfiguration of VSI Control Algorithms. This association yields an excellent dynamic performances at transient state as a result of VSI direct control method and low chattering at steady-state due to the VSI indirect control strategy. To support the proposed synthesis of DTSFC algorithms, simulation and experimental tests are given throughout the paper.

	Electromagnetic analysis of the induction motor with spiral sheet rotor By PERE; MUJA	[View] [Download]
Abstract: The study of the magnetic characteristics and constructive shapes of conductive materials, allows a better use of its electrical characteristics, reducing the maintenance and extending the life of the electrical machines. The improvements obtained on the torque with low currents using rotor with spiral sheets are analyzed on this paper. To have a complete study, several rotors and stators have been built to verify the electromagnetic variations on the three-phase asynchronous motors where they combine different constructive and mechanical characteristics of the related elements: changing inertias, constructive materials, and the geometrical shapes and disposition of the sheets. These different types of motors have been first tested in the laboratory, then, are simulated using computer aided tools (Matlab-Simulink). In particular four stators (1000 rpm, 1500rpm, 1500rpm-type A, and 3000 rpm) having the same constructive parameters, have been tested with the following rotors: solid rotor, solid rotor with diamagnetic rings, drag cup, and simple and double squirrel cage rotor. All these results have been compared to those obtained with the seven variants of spiral sheet rotor, presented on this paper. It has been demonstrated that it is possible to considerably reduce the starting currents, and therefore reducing the maintenance and extending the life of motors, without any negative consequence on the starting torque.

	Electronic stabilization methods for switched reluctance drives in weak supply nets By GERLING Dieter; SCHRAMM Andreas	[View] [Download]
Abstract: Smooth operation of reluctance machines concerning torque ripple and acoustic noise requires overlapping current flow in subsequent phases. In weak supply nets this may cause deep voltage drops resulting in critical states, e.g. for the microelectronic devices. This paper presents three electronic measures suitable for avoiding those deep voltage drops.

	Finite Element Analysis of A Novel Centrifugal Induction Blood Pump By TSENG King J.; WU Peng	[View] [Download]
Abstract: Axial-gap motors have flat profiles which make them suitable for use as wheel motors for electric vehicles or as shaft-less centrifugal pumps. In this paper, we present the investigation of an induction type of axial-gap motor using three-dimensional time-stepping finite element analysis. Unlike conventional radial-gap motor with circular cross-section throughout a relatively long axial length, axial-gap motors are not so suitable to be investigated by two-dimensional finite element analysis. Three-dimensional finite element analysis represents a higher order of technology, which has only now beginning to reach maturity. Time-stepping version of three-dimensional finite element software is now available, and we have applied it to study the characteristics of a dual stator large air gap axial flux induction motor and to optimize its rotor design.

	High-Performance Motion Control of Linear Motor Drives By BEINEKE Stephan	[View] [Download]
Abstract: This paper presents a high-performance linear drive control featuring encoder signal correction, oscil-lation damping and an advanced feedforward control for friction, speed and acceleration to reduce the dynamic trajectory errors. These measures and tools aiming at control optimization are investigated concerning their performance and benefits with linear drive systems. Major costs can be reduced by using magneto-resistive or hall effect based sensors. Different methods for determing the commutation angle allow to replace the absolute position encoders by incremental encoders. Specific analysis and commissioning tools allow an easy handling of the advanced features.

	IMPROVING EFFICIENCY IN SWITCHED RELUCTANCE MOTOR DRIVE WITH ON LINE CONTROL OF TURN-ON AND TURN-OFF ANGLES By TORRENT Marcel; BLANQUE Baldui; ANDRADA Pere; PERAT Jose Ignacio	[View] [Download]
Abstract: A current controlled switched reluctance motor drive for variable speed applications with efficiency optimisation is presented. Firing angles are computed online, the turn-on is calculated by means of the rule of Bose, and the turn-off is calculated using the general theory of the optimal turn-off angle proposed by Gribble. In steady state operation, the initial selection of firing angles is fine-tuned by means of an algorithm that minimizes the input power of the drive. A 6/4 switched reluctance motor drive prototype was tested and the experimental results show an improvement in online efficiency, a good steady-state performance and no deterioration in the dynamic response. An efficiency comparison with a commercial vector-controlled induction motor drive of the same size is also included.

	Method for Measuring Torques of Induction Motors for the Slip ranging from 0 to 2 by Detecting Twists of Stator By TAKANO Hiroo	[View] [Download]
Abstract: There is a negative torque at some slip when the locus of a rotating magnetic field is ellipse in a two-phase induction motor. A method for measuring the torque including the negative value continuously for the slip ranging from 0 to 2 is required for evaluating the trial motors and improving them, but there are few papers on this subject. In this paper the method for resolving this subject is proposed. It is based on the principle that the torque generated from the stator and the restoring torque from the springs of the sensors are balanced, and the twists of the stator which are proportional to the torques are transmitted to the sensors.In addition, a new method for determining the forward-field torque and backward-field torque separately are presented. They are obtained by detecting the fluxes linking with the closed circuit on the rotor, and by substituting the fluxes, resistance and reactance for the formulas. These calculated values agree well with the measured values for the forward-field torque vs. slip characteristics of the motor having the circular rotating magnetic field. Same result is obtained for the backward-field torque. Comparing two type of motors having the wound-rotor and the cast squirrel-cage rotor, it is clear that the ratio of the reactance to the resistance is the key factor to obtain the torque versus slip characteristics which a customer requires.

	Online Winding Temperature Monitoring of PWM Inverter-Fed Induction Machines By PLOTKIN Yuriy; STIEBLER Manfred	[View] [Download]
Abstract: A method for online winding temperature monitoring of PWM inverter-fed induction machines by injecting a d.c. bias into the stator voltage and using the resistance method is proposed. Advantageously no external devices are required for this method.

	POST-FAULT PERFORMANCE OF A FAULT TOLERANT SWITCHED RELUCTANCE MOTOR DRIVE By MARTINEZ Eusebi; ANDRADA Pere; SANCHEZ Jose Antonio; BLANQUE Baldui; PERAT Jose Ignacio; TORRENT Marcel	[View] [Download]
Abstract: A current controlled switched reluctance motor drive for variable speed applications with efficiency optimisation is presented. Firing angles are computed online, the turn-on is calculated by means of the rule of Bose, and the turn-off is calculated using the general theory of the optimal turn-off angle proposed by Gribble. In steady state operation, the initial selection of firing angles is fine-tuned by means of an algorithm that minimizes the input power of the drive. A 6/4 switched reluctance motor drive prototype was tested and the experimental results show an improvement in online efficiency, a good steady-state performance and no deterioration in the dynamic response. An efficiency comparison with a commercial vector-controlled induction motor drive of the same size is also included.

	Stability Analysis of a BDFM under Open-Loop Voltage Control By ROYE Daniel; SARASOLA Izaskun; POZA Javier; OYARBIDE Estanis	[View] [Download]
Abstract: This paper presents a stability analysis of the Brushless Doubly-Fed Machine (BDFM) under Open-Loop Voltage Control (OLVC). For this purpose a new small signal model has been developed. This new model takes into account the dynamic characteristics of the load. This study is validated in a experimental machine prototype.

	TRANSIENT ANALYSIS OF PERMANENT MAGNET LINEAR SYNCHRONOUS MOTORS By GENTILE Giuseppe; ROTONDALE Nicola; OMETTO Antonio	[View] [Download]
Abstract: A modified one-dimensional mathematical model based on the space-vectors theory is used to analyse the performance of permanent magnet linear synchronous motors with starting and dumping sheet. The end-effects are taken into account by assuming that the length of the iron core is infinite and the length of the armature winding is finite. The resulting differential equation set allows both steady state and transient operations to be analysed. The model is used to analyse the transient performance (starting and load step) of two low power motors.