EPE Association: EPE 2001 - Topic 06f: Sensorless Techniques

EPE 2001 - Topic 06f: Sensorless Techniques
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 06: ELECTRICAL MACHINES AND ADJUSTABLE SPEED DRIVES > EPE 2001 - Topic 06f: Sensorless Techniques

   [return to parent folder]

   A Unified Predictive DTC Algorithm for AC Machine Sensorless Control
By M. S. Carmeli; A. Monti [View]
[Download]

Abstract: This paper proposes a new unified sensorless Direct Torque Control (DTC) algorithm for AC machines. The scheme overcomes the main DTC limits. In particular a predictive algorithm able to control both stator flux and torque is introduced and a constant inverter switching frequency is obtained. Laboratory results on brushless and asynchronous machine are reported.

   BLDC Motor Position Detection at Standstill
By F. Bonvin; Y. Perriard [View]
[Download]

Abstract: In some applications, it is interesting to know the position of a BLDC Motor at standstill. This paper propose one solution using the saturation property of the motor. Principle, simulation and measures are presented. The results of industrial applications are exposed and discussed. Several preview works has been done on this subject. The purpose of this paper is to present a new method allowing to enhance the precision up to 2°. Furthermor, the method can be applied to all type of brushless DC motors, even with airgap or toothless ones.

   Doubly-fed a.c.machines: classification and comparison
By B. Hopfensperger; D. J. Atkinson [View]
[Download]

Abstract: A doubly-fed machine is a three phase a.c. machine with two accessible three phase windings from which power can be fed to or extracted from. This paper classifies and describes the various types of such an electrical machine with their potential in variable-speed constant-frequency applications. Construction issues, frequency behaviour, power flow, modeling and control are the main focus points. Covered machines are the single doubly-fed (wound rotor ) induction machine (SDFM), the cascaded doubly-fed induction machine (CDFM), the single-frame cascaded doubly-fed induction machine (SF-CDFM), the so-called brushless doubly-fed induction machine (BDFM), the doubly-fed reluctance machine (DFRM) and the tandem induction machine (TIM). A comparison list concludes this machine overview.

   DSP-based intelligent motion control
By S. Beierke; J.C. Soroka; P. Vas [View]
[Download]

Abstract: At present there is a rapid increase in the number of digital signal processors (DSPs) for various motion control applications. However, a very significant further increase is expected in the near future due to wider applications in existing and new areas: domestic appliances, automotive auxiliaries, micro-electromechanical systems, military systems, etc. The present paper discusses the state-of-the-art Texas Instruments (TI) fixed point and floating point DSPs used in motion control applications and will also focus on future activities.

   Dynamical performances of sensorless IM drive with different observers
By T. Orlowska-Kowalska; P. Wojsznis; C.T. Kowalski [View]
[Download]

Abstract: Sensorless vector control of induction motor drives requires knowledge of the instantaneous value of the rotor flux and speed. Various methods of the rotor flux and speed estimation were recently used, based on the mathematical models of the induction machine, on nonlinear phenomena caused by rotor excentricity or other motor saliences and based on neural networks. The main goal of the paper is the comparison of chosen flux and speed observers in simulation – from the point of view of sensitivity to motor parameter changes, as well as in experiments - from the point of view of proper work in dynamical states and low speed region. The four different concepts were tested: two flux simulators, reduced and full order flux observers, with speed calculated based on estimated flux components and so called adaptive speed observ er (MRAS) based on full order flux observer and adaptive speed loop. The results of simulated and laboratory tests are presented and the estimation quality is evaluated.

   Encoderless Position Control of Induction Machines
By N. Teske; G. M. Asher; M. Sumner; K. J. Bradley [View]
[Download]

Abstract: This paper presents advances in sensorless position control of induction machines using a standard or ‘symmetric’ rotor. The rotor position information is obtained by high frequency voltage injection and using the modulating eect of the rotor slots. This makes true sensorless control possible, including zero speed. The deteriorating eect of saturation-induced saliencies at full flux and higher loads is suppressed by using a new harmonic compensation scheme which we term Space-Modulation Profiling (SMP). This method also reduces the unwanted modulation of the high frequency voltage at the instance of a fundamental current crossing through zero due to inverter deadtime. This paper analyzes the distorting modulation due to saturation and current zero-crossing and shows the decoupling of the position harmonics via SMP as a solution to enhance the position estimation accuracy. Results are presented, showing true sensorless position control at full flux and under high load which has not been published before.

   Im Rotor Position Detection For Diagnostic Or Control Aims
By A. Bellini; G. Franceschini; N.Petrolini; C. Tassoni; F. Filippetti [View]
[Download]

Abstract: Electrical and magnetic asymmetries are an intrinsic property of electric machines and, depending on machine type, can be used for both diagnosis and control. Specifically for control purposes these asymmetries are used to track the angular information, while monitoring their anomalous amplitude can solve diagnosis task. In this paper the modelization of induction machines with rotor asymmetries is recalled and reviewed in order to show that asymmetries induced by broken rotor bars can be used efficiently for both sensorless control and on-line diagnosis of electric drives.

   Improved Control Of Induction Motor Drives Without A Shaft Sensor
By G. Terörde; R. Belmans [View]
[Download]

Abstract: Induction motors are relatively cheap and rugged machines. Only a closed loop control of the motor meets the requirements including fast dynamic response, accurate speed and torque control or even a higher efficiency by means of flux optimization. However, the speed sensor has several disadvantages from the viewpoint of drive cost, reliability and signal noise immunity. This paper deals with the speed control of induction motor drives without a shaft sensor. Here, a new model for speed estimation is proposed. Its structure is based on the Extended Kalman Filter theory. A 1,5 kW induction motor experimental system has been built to verify this approach. Experimental results are presented to demonstrate the performance of the system.

   Improved rotor position estimation for maximum torque/current control
By S. Stasi; L. Salvatore; F. Cupertino [View]
[Download]

Abstract: This paper presents a novel PMSM sensorless control scheme. The observed rotor position is obtained from the active and reactive electromagnetic torque calculated in both the stationary á−â and rotor d-q reference frame. This observed rotor position is improved by the addition of a term, derived from the d-axis current controller voltage output, and used for the coordinate transformation. The further compensation of the global time-delay, introduced by the voltage-, current-filters, and inverter, has to be added to the estimated rotor position to calculate the current feedback signals and obtain maximum torque/current control of the drive. The original scheme guarantees a good field orientation even if parameter variations occur and/or initial rotor position is not exactly known.

   Improving the dynamic performance of carrier signal injection based se
By F. Briz; M.W. Degner; J.M. Guerrero; A. Diez [View]
[Download]

Abstract: This paper analyzes the problems caused by the interaction between the fundamental current and the carrier signal current in carrier signal injection based sensorless AC drives. This interaction can be caused by a lack of spectral separation between the two signals during steady-state operation or by transients in the fundamental current. Both of these phenomena are first analyzed and then a solution based on dynamic decoupling using a fundamental current observer is proposed.

   Influence of Rotor design on sensorless control for induction motors
By T. M. Wolbank; R. Wöhrnschimmel [View]
[Download]

Abstract: Sensorless, field oriented control of standard induction motors at and near zero frequency can only be achieved by exploiting inherent saliencies. The two most prominent saliencies, which are usually exploited are caused by saturation and slotting, thus enable the detection of the main flux and the rotor position. The influence of these saliencies is not evident in normal operation of the drive. However, it can be detected with a high frequency or transient excitation caused by the inverter. Therefore, the high-frequency response is evaluated to obtain the control signal. As the interaction of all saliencies may lead to a deterioration of the performance of the sensorless control algorithm in specific points of operation it is advantageous to exploit only one saliency trying to compensate the influence of the others. To facilitate this separation, different machine design parameters can be adjusted reference to the saliency which has to be suppressed. This paper is focused on the influence of different rotor design parameters on the sensorless control signal. Measurements were performed reference to sensorless control and to the spatial distribution of the transient flux change measured with test coils placed at different areas of the machines. To achieve this, differently designed machines have been manufactured, only influencing the saliencies present in standard induction machines. In addition results obtained from simulations covering transient hysteresis effects are presented and compared to give a further insight into the transient electrical behaviour of induction machines. The sensorless control scheme applied in this paper is based on a transient excitation of the machine. It detects local differences in the stator impedance of the machine caused by spatial saliencies by evaluating the transient current change due to voltage pulses applied to the terminals of the machine.

   Novell hardware current controller for sensorl. INFORM based PM-drives
By E. Robeischl; M. Schrödl; R. Kremsl [View]
[Download]

Abstract: This paper presents a newly developed discrete-time hardware current controller based on DC-link current measurement. It is combined with a sensorless PMSM drive, which can be operated with highly dynamic properties in the full speed range including low speed and standstill.

   Position Estimation of Hybrid Stepper Motors Including Zero Speed
By P. Aicher [View]
[Download]

Abstract: A sensorless method for rotor position estimation of a hybrid stepper motor has been developed. Injecting a high frequency carrier voltage to track spatial inductance variations the method works at low speeds and at standstill. The influence of speed and load conditions on the estimation error is investigated.

   Position Sensorless PMSM DTC-Drive for Industrial Applications
By M. Niemelä; J. Luukko; J. Pyrhönen [View]
[Download]

Abstract: Permanent magnet synchronous motors (PMSM) have become attractive to many variable speed industrial applications in medium and large power drives. In this paper a sensorless DTC-drive for a PMSM is presented. The principle of determination of the initial rotor position at start-up, the operation at zero speed and at low rotational speeds in general are described. Some of the results of the numerous experiments performed with a laboratory prototype drive are given.

   Rotor Speed and Position Observer for PMSM Sensorless Control System
By K. Urbanski; K. Zawirski [View]
[Download]

Abstract: A problem of rotor speed and position detection for sensorless PMSM drive was analysed in the paper. The concept based on detecting back EMF, induced in the stator windings, was developed and modified. A general structure of observer, with more complex function of corrector than traditional one was introduced. On the base of this concept the observer with proportional-integral and sliding mode correction was proposed. Simulation as well as experimental results showed good properties of proposed observer structure.

   Sensorless control system of DFM with predictive current controller
By Z. Krzeminski; A. Popenda; M. Melcer; P. Ladach [View]
[Download]

Abstract: A control system for the double fed induction machine is presented in the paper. The measurement of the rotor position angle is avoided in the proposed system because of application of phase locked loop for synchronization of rotor current with stator voltage. Two cases of the rotor current control are considered: the first one is the independent control of the rotor current components by hysteresis controllers in a three-phase system, and the second one is the control using predictive current controller. The control systems for the double fed machine have been investigated by simulations and experimentally and their properties are compared.

   Sensorless Field Oriented Induction Motor Control Using Test Signals
By C. Rudolph; U. Schümann; B. Orlik [View]
[Download]

Abstract: The sensorless field oriented control of induction motor drives requires the calculation of the flux angle and the speed by a model from stator voltages and currents. A new method is described to identify the flux angle even down to zero Hertz stator frequency, thus stable operation of the sensorless controlled drive is ensured in the entire torque-speed plane. If model parameters deviate from machine parameters the quality of the control deteriorates. Therefore the machine parameters have to be identified accurately before starting the control. During operation the sensorless control can be improved by an online adaptation of the stator and the rotor resistance using a thermal observer.

   Sensorless Induction Motor Drive for Speed Synchronised Apps
By G. Turl; M. Sumner; G. M. Asher [View]
[Download]

Abstract: This paper presents a high performance sensorless induction motor drive that is based on the machine electrical model and tuned by a robust speed estimate. This estimate is obtained from an adaptive algorithm tracking rotor slot harmonics that appear in voltage and current quantities. The resultant system is tested for use in multi-motor, speed synchronised drives, an application typically requiring encodered performance. Excellent system performance is demonstrated on a dual 4kW experimental rig.

   Sensorless Speed Detection using Walevet Decomposition
By A. Obradovic; M. Djurovic; G. Joksimovic [View]
[Download]

Abstract: By using the Wavelet decomposition in time domain and the measurements of the stator current one can determine the speed of induction machines without having any sensor. The use of the Wavelet decomposition eliminates some disadvantages, which are brought in calculations using STFT. It has produced results in shorter time for the same accuracy.

   Sensorless vector controlled induction motor drive employing an ANN.
By J. A. Campbell; M. Sumner [View]
[Download]

Abstract: This paper describes a novel high performance sensorless vector controlled induction motor drive. Sensorless speed control is achieved using a Model Reference Adaptive System which employs a Closed Loop Flux Observer for field orientation. To improve low speed operation the system uses an Artificial Neural Network to estimate changes in the stator resistance. This ensures correct orientation and speed estimation, with distinct improvements to drive stability, especially when the resistive voltage drops become significant at lower speeds. Experimental results are presented to verify this.

   Speed Adaptive Kalman filter observer for induction motors
By J. L. Mora; A. Torralba; L. G. Franquelo [View]
[Download]

Abstract: The extended Kalman filter has been applied extensively for speed and flux estimation in induction machines. The main drawback of this estimator is its complexity, and related to his, the high sample time needed for its implementation in a DSP, so the expected performance is greatly reduced. This paper presents a linear Kalman filter for rotor flux observation with adaptive speed estimation that reduces the number of operations by a factor of 8.5 compared with the straightforward implementation of the extended Kalman filter. This estimator and an indirect vector control algorithm has been implemented in a single DSP, allowing a sample time of only 50µs. The experimental results shows a great dynamic performance, low speed error and a good response in low speed operation.

   Speed Sensorless SM Torque and Flux Contr. of IM with Stat. Res. Adapt
By M. Rodiè; K. Jezernik [View]
[Download]

Abstract: Speed sensorless induction motor torque and flux tracking control algorithm is presented. Proposed approach addresses the problem of operation at both, low and high speed. The idea is realized using a non-linear flux observer by introducing a non-linear stator frequency dependent gain and stator resistance adaptation algorithm. The analysis of the proposed method is included. A presented stator resistance adaptation algorithm makes the observer robust to the parameter uncertainties. The performance is investigated and verified with experiments.

   Speed Sensorless Vector Control of Parallel Connected Dual IM
By Y. Kono; H. Kawai; S. Yokomizo; K. Matsuse [View]
[Download]

Abstract: The purpose of this work is to present the speed-sensorless vector control method of the torque production from each rotor of two induction motors with parallel connected stator windings fed by a single inverter. In this paper an adaptive rotor flux observer is applied to the method in order to eliminate a flux sensor, and an adaptive scheme for rotor speed is added to the adaptive rotor flux observer in order to eliminate a speed sensor. The experimental results show that the proposed method is useful under the rating of each induction motor are different.

   Synthesis Models of SPM Motors for the Design of Complex Systems
By Y. Fefermann; S.-A. Randi; S. Astier; X. Roboam [View]
[Download]

Abstract: This paper presents an original procedure for the design of PM motor, characterised by its low cost in computation time fitted with the optimal design of complex and heterogeneous systems. The method is based on two analytical models of PM machines. Particularly, a new model of synthesis, based on similarity laws drawn from field equations, is presented. It enables to find by easy and rapid calculations the new circuit parameters when the system geometry change.

EPE 2001 - Topic 06f: Sensorless Techniques
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 06: ELECTRICAL MACHINES AND ADJUSTABLE SPEED DRIVES > EPE 2001 - Topic 06f: Sensorless Techniques
	[return to parent folder]

	A Unified Predictive DTC Algorithm for AC Machine Sensorless Control By M. S. Carmeli; A. Monti	[View] [Download]
Abstract: This paper proposes a new unified sensorless Direct Torque Control (DTC) algorithm for AC machines. The scheme overcomes the main DTC limits. In particular a predictive algorithm able to control both stator flux and torque is introduced and a constant inverter switching frequency is obtained. Laboratory results on brushless and asynchronous machine are reported.

	BLDC Motor Position Detection at Standstill By F. Bonvin; Y. Perriard	[View] [Download]
Abstract: In some applications, it is interesting to know the position of a BLDC Motor at standstill. This paper propose one solution using the saturation property of the motor. Principle, simulation and measures are presented. The results of industrial applications are exposed and discussed. Several preview works has been done on this subject. The purpose of this paper is to present a new method allowing to enhance the precision up to 2°. Furthermor, the method can be applied to all type of brushless DC motors, even with airgap or toothless ones.

	Doubly-fed a.c.machines: classification and comparison By B. Hopfensperger; D. J. Atkinson	[View] [Download]
Abstract: A doubly-fed machine is a three phase a.c. machine with two accessible three phase windings from which power can be fed to or extracted from. This paper classifies and describes the various types of such an electrical machine with their potential in variable-speed constant-frequency applications. Construction issues, frequency behaviour, power flow, modeling and control are the main focus points. Covered machines are the single doubly-fed (wound rotor ) induction machine (SDFM), the cascaded doubly-fed induction machine (CDFM), the single-frame cascaded doubly-fed induction machine (SF-CDFM), the so-called brushless doubly-fed induction machine (BDFM), the doubly-fed reluctance machine (DFRM) and the tandem induction machine (TIM). A comparison list concludes this machine overview.

	DSP-based intelligent motion control By S. Beierke; J.C. Soroka; P. Vas	[View] [Download]
Abstract: At present there is a rapid increase in the number of digital signal processors (DSPs) for various motion control applications. However, a very significant further increase is expected in the near future due to wider applications in existing and new areas: domestic appliances, automotive auxiliaries, micro-electromechanical systems, military systems, etc. The present paper discusses the state-of-the-art Texas Instruments (TI) fixed point and floating point DSPs used in motion control applications and will also focus on future activities.

	Dynamical performances of sensorless IM drive with different observers By T. Orlowska-Kowalska; P. Wojsznis; C.T. Kowalski	[View] [Download]
Abstract: Sensorless vector control of induction motor drives requires knowledge of the instantaneous value of the rotor flux and speed. Various methods of the rotor flux and speed estimation were recently used, based on the mathematical models of the induction machine, on nonlinear phenomena caused by rotor excentricity or other motor saliences and based on neural networks. The main goal of the paper is the comparison of chosen flux and speed observers in simulation – from the point of view of sensitivity to motor parameter changes, as well as in experiments - from the point of view of proper work in dynamical states and low speed region. The four different concepts were tested: two flux simulators, reduced and full order flux observers, with speed calculated based on estimated flux components and so called adaptive speed observ er (MRAS) based on full order flux observer and adaptive speed loop. The results of simulated and laboratory tests are presented and the estimation quality is evaluated.

	Encoderless Position Control of Induction Machines By N. Teske; G. M. Asher; M. Sumner; K. J. Bradley	[View] [Download]
Abstract: This paper presents advances in sensorless position control of induction machines using a standard or ‘symmetric’ rotor. The rotor position information is obtained by high frequency voltage injection and using the modulating eect of the rotor slots. This makes true sensorless control possible, including zero speed. The deteriorating eect of saturation-induced saliencies at full flux and higher loads is suppressed by using a new harmonic compensation scheme which we term Space-Modulation Profiling (SMP). This method also reduces the unwanted modulation of the high frequency voltage at the instance of a fundamental current crossing through zero due to inverter deadtime. This paper analyzes the distorting modulation due to saturation and current zero-crossing and shows the decoupling of the position harmonics via SMP as a solution to enhance the position estimation accuracy. Results are presented, showing true sensorless position control at full flux and under high load which has not been published before.

	Im Rotor Position Detection For Diagnostic Or Control Aims By A. Bellini; G. Franceschini; N.Petrolini; C. Tassoni; F. Filippetti	[View] [Download]
Abstract: Electrical and magnetic asymmetries are an intrinsic property of electric machines and, depending on machine type, can be used for both diagnosis and control. Specifically for control purposes these asymmetries are used to track the angular information, while monitoring their anomalous amplitude can solve diagnosis task. In this paper the modelization of induction machines with rotor asymmetries is recalled and reviewed in order to show that asymmetries induced by broken rotor bars can be used efficiently for both sensorless control and on-line diagnosis of electric drives.

	Improved Control Of Induction Motor Drives Without A Shaft Sensor By G. Terörde; R. Belmans	[View] [Download]
Abstract: Induction motors are relatively cheap and rugged machines. Only a closed loop control of the motor meets the requirements including fast dynamic response, accurate speed and torque control or even a higher efficiency by means of flux optimization. However, the speed sensor has several disadvantages from the viewpoint of drive cost, reliability and signal noise immunity. This paper deals with the speed control of induction motor drives without a shaft sensor. Here, a new model for speed estimation is proposed. Its structure is based on the Extended Kalman Filter theory. A 1,5 kW induction motor experimental system has been built to verify this approach. Experimental results are presented to demonstrate the performance of the system.

	Improved rotor position estimation for maximum torque/current control By S. Stasi; L. Salvatore; F. Cupertino	[View] [Download]
Abstract: This paper presents a novel PMSM sensorless control scheme. The observed rotor position is obtained from the active and reactive electromagnetic torque calculated in both the stationary á−â and rotor d-q reference frame. This observed rotor position is improved by the addition of a term, derived from the d-axis current controller voltage output, and used for the coordinate transformation. The further compensation of the global time-delay, introduced by the voltage-, current-filters, and inverter, has to be added to the estimated rotor position to calculate the current feedback signals and obtain maximum torque/current control of the drive. The original scheme guarantees a good field orientation even if parameter variations occur and/or initial rotor position is not exactly known.

	Improving the dynamic performance of carrier signal injection based se By F. Briz; M.W. Degner; J.M. Guerrero; A. Diez	[View] [Download]
Abstract: This paper analyzes the problems caused by the interaction between the fundamental current and the carrier signal current in carrier signal injection based sensorless AC drives. This interaction can be caused by a lack of spectral separation between the two signals during steady-state operation or by transients in the fundamental current. Both of these phenomena are first analyzed and then a solution based on dynamic decoupling using a fundamental current observer is proposed.

	Influence of Rotor design on sensorless control for induction motors By T. M. Wolbank; R. Wöhrnschimmel	[View] [Download]
Abstract: Sensorless, field oriented control of standard induction motors at and near zero frequency can only be achieved by exploiting inherent saliencies. The two most prominent saliencies, which are usually exploited are caused by saturation and slotting, thus enable the detection of the main flux and the rotor position. The influence of these saliencies is not evident in normal operation of the drive. However, it can be detected with a high frequency or transient excitation caused by the inverter. Therefore, the high-frequency response is evaluated to obtain the control signal. As the interaction of all saliencies may lead to a deterioration of the performance of the sensorless control algorithm in specific points of operation it is advantageous to exploit only one saliency trying to compensate the influence of the others. To facilitate this separation, different machine design parameters can be adjusted reference to the saliency which has to be suppressed. This paper is focused on the influence of different rotor design parameters on the sensorless control signal. Measurements were performed reference to sensorless control and to the spatial distribution of the transient flux change measured with test coils placed at different areas of the machines. To achieve this, differently designed machines have been manufactured, only influencing the saliencies present in standard induction machines. In addition results obtained from simulations covering transient hysteresis effects are presented and compared to give a further insight into the transient electrical behaviour of induction machines. The sensorless control scheme applied in this paper is based on a transient excitation of the machine. It detects local differences in the stator impedance of the machine caused by spatial saliencies by evaluating the transient current change due to voltage pulses applied to the terminals of the machine.

	Novell hardware current controller for sensorl. INFORM based PM-drives By E. Robeischl; M. Schrödl; R. Kremsl	[View] [Download]
Abstract: This paper presents a newly developed discrete-time hardware current controller based on DC-link current measurement. It is combined with a sensorless PMSM drive, which can be operated with highly dynamic properties in the full speed range including low speed and standstill.

	Position Estimation of Hybrid Stepper Motors Including Zero Speed By P. Aicher	[View] [Download]
Abstract: A sensorless method for rotor position estimation of a hybrid stepper motor has been developed. Injecting a high frequency carrier voltage to track spatial inductance variations the method works at low speeds and at standstill. The influence of speed and load conditions on the estimation error is investigated.

	Position Sensorless PMSM DTC-Drive for Industrial Applications By M. Niemelä; J. Luukko; J. Pyrhönen	[View] [Download]
Abstract: Permanent magnet synchronous motors (PMSM) have become attractive to many variable speed industrial applications in medium and large power drives. In this paper a sensorless DTC-drive for a PMSM is presented. The principle of determination of the initial rotor position at start-up, the operation at zero speed and at low rotational speeds in general are described. Some of the results of the numerous experiments performed with a laboratory prototype drive are given.

	Rotor Speed and Position Observer for PMSM Sensorless Control System By K. Urbanski; K. Zawirski	[View] [Download]
Abstract: A problem of rotor speed and position detection for sensorless PMSM drive was analysed in the paper. The concept based on detecting back EMF, induced in the stator windings, was developed and modified. A general structure of observer, with more complex function of corrector than traditional one was introduced. On the base of this concept the observer with proportional-integral and sliding mode correction was proposed. Simulation as well as experimental results showed good properties of proposed observer structure.

	Sensorless control system of DFM with predictive current controller By Z. Krzeminski; A. Popenda; M. Melcer; P. Ladach	[View] [Download]
Abstract: A control system for the double fed induction machine is presented in the paper. The measurement of the rotor position angle is avoided in the proposed system because of application of phase locked loop for synchronization of rotor current with stator voltage. Two cases of the rotor current control are considered: the first one is the independent control of the rotor current components by hysteresis controllers in a three-phase system, and the second one is the control using predictive current controller. The control systems for the double fed machine have been investigated by simulations and experimentally and their properties are compared.

	Sensorless Field Oriented Induction Motor Control Using Test Signals By C. Rudolph; U. Schümann; B. Orlik	[View] [Download]
Abstract: The sensorless field oriented control of induction motor drives requires the calculation of the flux angle and the speed by a model from stator voltages and currents. A new method is described to identify the flux angle even down to zero Hertz stator frequency, thus stable operation of the sensorless controlled drive is ensured in the entire torque-speed plane. If model parameters deviate from machine parameters the quality of the control deteriorates. Therefore the machine parameters have to be identified accurately before starting the control. During operation the sensorless control can be improved by an online adaptation of the stator and the rotor resistance using a thermal observer.

	Sensorless Induction Motor Drive for Speed Synchronised Apps By G. Turl; M. Sumner; G. M. Asher	[View] [Download]
Abstract: This paper presents a high performance sensorless induction motor drive that is based on the machine electrical model and tuned by a robust speed estimate. This estimate is obtained from an adaptive algorithm tracking rotor slot harmonics that appear in voltage and current quantities. The resultant system is tested for use in multi-motor, speed synchronised drives, an application typically requiring encodered performance. Excellent system performance is demonstrated on a dual 4kW experimental rig.

	Sensorless Speed Detection using Walevet Decomposition By A. Obradovic; M. Djurovic; G. Joksimovic	[View] [Download]
Abstract: By using the Wavelet decomposition in time domain and the measurements of the stator current one can determine the speed of induction machines without having any sensor. The use of the Wavelet decomposition eliminates some disadvantages, which are brought in calculations using STFT. It has produced results in shorter time for the same accuracy.

	Sensorless vector controlled induction motor drive employing an ANN. By J. A. Campbell; M. Sumner	[View] [Download]
Abstract: This paper describes a novel high performance sensorless vector controlled induction motor drive. Sensorless speed control is achieved using a Model Reference Adaptive System which employs a Closed Loop Flux Observer for field orientation. To improve low speed operation the system uses an Artificial Neural Network to estimate changes in the stator resistance. This ensures correct orientation and speed estimation, with distinct improvements to drive stability, especially when the resistive voltage drops become significant at lower speeds. Experimental results are presented to verify this.

	Speed Adaptive Kalman filter observer for induction motors By J. L. Mora; A. Torralba; L. G. Franquelo	[View] [Download]
Abstract: The extended Kalman filter has been applied extensively for speed and flux estimation in induction machines. The main drawback of this estimator is its complexity, and related to his, the high sample time needed for its implementation in a DSP, so the expected performance is greatly reduced. This paper presents a linear Kalman filter for rotor flux observation with adaptive speed estimation that reduces the number of operations by a factor of 8.5 compared with the straightforward implementation of the extended Kalman filter. This estimator and an indirect vector control algorithm has been implemented in a single DSP, allowing a sample time of only 50µs. The experimental results shows a great dynamic performance, low speed error and a good response in low speed operation.

	Speed Sensorless SM Torque and Flux Contr. of IM with Stat. Res. Adapt By M. Rodiè; K. Jezernik	[View] [Download]
Abstract: Speed sensorless induction motor torque and flux tracking control algorithm is presented. Proposed approach addresses the problem of operation at both, low and high speed. The idea is realized using a non-linear flux observer by introducing a non-linear stator frequency dependent gain and stator resistance adaptation algorithm. The analysis of the proposed method is included. A presented stator resistance adaptation algorithm makes the observer robust to the parameter uncertainties. The performance is investigated and verified with experiments.

	Speed Sensorless Vector Control of Parallel Connected Dual IM By Y. Kono; H. Kawai; S. Yokomizo; K. Matsuse	[View] [Download]
Abstract: The purpose of this work is to present the speed-sensorless vector control method of the torque production from each rotor of two induction motors with parallel connected stator windings fed by a single inverter. In this paper an adaptive rotor flux observer is applied to the method in order to eliminate a flux sensor, and an adaptive scheme for rotor speed is added to the adaptive rotor flux observer in order to eliminate a speed sensor. The experimental results show that the proposed method is useful under the rating of each induction motor are different.

	Synthesis Models of SPM Motors for the Design of Complex Systems By Y. Fefermann; S.-A. Randi; S. Astier; X. Roboam	[View] [Download]
Abstract: This paper presents an original procedure for the design of PM motor, characterised by its low cost in computation time fitted with the optimal design of complex and heterogeneous systems. The method is based on two analytical models of PM machines. Particularly, a new model of synthesis, based on similarity laws drawn from field equations, is presented. It enables to find by easy and rapid calculations the new circuit parameters when the system geometry change.