EPE Association: EPE 2003 - Topic 07d: Sensorless Techniques

EPE 2003 - Topic 07d: Sensorless Techniques
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 07: MEASUREMENTS AND SENSORS > EPE 2003 - Topic 07d: Sensorless Techniques

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   Self-sensing active magnetic bearings using a new PWM amplifier equiped with a bias voltage source
By T. Yoshida; Y. Kuroba; K. Ohniwa; O. Miyashita [View]
[Download]

Abstract: In this paper, a self-sensing active magnetic bearing (AMB) with a new PWM amplifier is proposed. This amplifier employs two DC sources: one supplies a control current and the other supplies a bias current. A pair of electromagnets driven by this amplifier also works as a position sensor based on bridge measurement. In the experiment, a rotor running at 45,000 min-1 is suspended by the proposed 5-axis AMB without any position sensors. The experimental system is still stable even if the length of the cables between the PWM amplifiers and the electromagnets is varied within 45 meters.

   Model-based speed identification for induction machines in the whole operating range
By M. Depenbrock; C. Evers [View]
[Download]

Abstract: A speed observer for induction machines without rotational transducers is presented. In contrast to known adaptive observer strategies, the proposed scheme uses the conventional current difference and a new stretch-twist operator to avoid the known instability region and to obtain a constant gain additionally. Furthermore a parasitic dc-component elimination is presented to ensure operation with very low stator frequencies. Characteristics are explained and verified by measurements.

   Optimization of saliency effects of external rotor permanent magnet synchronous motors with respect to enhanced INFORM-capability for sensorless control
By U.H. Rieder; M. Schroedl [View]
[Download]

Abstract: In many applications like traction, starter generators, and direct drives the need for high torque is the basic issue. This paper presents the combination of advantages of external rotor PMSMs and sensorless control algorithms, especially for low speed using the INFORM-method (Indirect Flux Detection by Online Reactance Measurement). Therefore saliency and saturation effects have to be taken into consideration and can be enforced for improved INFORM performance.

   Nonlinear state-observer techniques for sensorless control of automotive PMSM’s, including load-torque estimation and saliency
By B.S. Bhangu; C.M. Bingham [View]
[Download]

Abstract: The paper investigates various non-linear observer-based rotor position estimation schemes for sensorless control of permanent magnet synchronous motors (PMSMs). Attributes of particular importance to the application of brushless motors in the automotive sector, are considered e.g. implementation cost, accuracy of predictions during load transients, the impact of motor saliency and algorithm complexity. Emphasis is given to techniques based on model linearisation during each sampling period (EKF); feedback-linearisation followed by Luenberger observer design based on the resulting ‘linear’ motor characteristics; and direct design of non-linear observers. Although the benefits of sensorless commutation of PMSMs have been well expounded in the literature, an integrated approach to their design for application to salient machines subject to load torque transients remains outstanding. Furthermore, this paper shows that the inherent characteristics of some non-linear observer structures are particularly attractive since they provide a phase-locked-loop (PLL)-type of configuration that can encourage stable rotor position estimation, thereby enhancing the overall sensorless scheme. Moreover, experimental results show how operation through, and from, zero speed, is readily obtainable. Experimental results are also employed to demonstrate the attributes of each methodology, and provide dynamic and computational performance comparisons.

   Anisotropy in induction machine lamination and its influence on mechanical sensorless control and condition monitoring
By T. M. Wolbank; J. L. Machl; H. Hauser; P. Macheiner [View]
[Download]

Abstract: In the application of inverter-fed ac-machines, the lamination material used shows - despite of all assumptions - not too little material anisotropy effects. Since the sheets have a sufficiently small thickness and are manufactured by a rolling and punching process, they meet all physical requirements to show anisotropic distribution of the crystalline energy. The effect is smaller than known for the grain-oriented steels applied in transformers, however is still observable, as measurements on lamination material specimen will show. Lamination material anisotropy has mostly been neglected up to now, because the fundamental wave behaviour of induction machines is only negligible influenced. Although this effect is only visible in the transient electrical behaviour, in some cases it has to be considered to ensure proper function and high dynamics of sensorless controlled ac-drives. However, not only mechanical sensorless control but also condition monitoring schemes for acmachines evaluate this transient electrical behaviour and thus the lamination material anisotropy effects are of great importance in these fields.

   Robust observer for sensorless control of synchronous drive with uncertain parameters
By L. Peyras; S. Caux; M. Fadel [View]
[Download]

Abstract: This paper presents a robust observer based on redundancy computing emf on 2 axis rotor oriented reference frame. the first step is a stalling phase avoiding any wrong rotation whatever the rotor initial position is. The second step is a calibration phase, to estimate accurately the electrical parametres of the drive. Using the first two steps, we finally control the sensorless drive by estimating emf, velocity and position which are quite close to reality only by voltage and current measurements.

   Precision improvement of IPM motor position sensorless control with PWM inverter carrier frequency component method
By J. Oyama; T. Higuchi; T. Abe; D. Itoyama; M. Mamo [View]
[Download]

Abstract: We proposed carrier frequency component method (CFCM) for position sensor-less control of IPM motor, in which we utilized carrier frequency component current of PWM inverter as the motor position information source. In this paper, we present a compensation method to improve the accuracy of CFCM position estimation. In the experiments, the motor has been successfully controlled from zero speed to 1,350rpm without mechanical sensor.

   Wide bandwidth sensorless position control using a superimposed synchronous test signal
By H.G. Köpken [View]
[Download]

Abstract: Sensorless servo control requires fast, on-line rotor position estimation during standstill. This paper presents a way to calculate a position estimate in every PWM cycle. It uses a test signal with full PWM frequency. A decoupling algorithm eliminates the effect of fast current changes on the position estimates. Measurements of position command tracking and transient load behaviour are shown.

   Hybrid sensorless position observation of a brushless DC motor
By S. Grainger; M. Allan [View]
[Download]

Abstract: Hybrid schemes offer the possibility of improved performance over existing schemes through the combination of desirable features from multiple technologies. A hybrid system is developed for the estimation of rotor position within brushless DC motors (BLDCM). This comprises a sliding mode observer for parameter robustness, a modified integrator for drift free operation under bias conditions and an artificial neural network (ANN) for data fusion and mapping functions. Results show the system to be extremely robust and to have good accuracy.

   Initial rotor position estimation for an integrated starter alternator IPM synchronous machine
By H. Kim; K.-K. Huh; M. Harke; J. Wai; R. D. Lorenz; T. M. Jahns [View]
[Download]

Abstract: Novel methods for initial position estimation during start-up are presented for an integrated starter alternator interior permanent magnet synchronous machine. The magnet cavities in the IPMSM rotor create a sizable difference in the inductances of the two orthogonal rotor axes. This spatial saliency base on the rotor position makes it possible to use persistent, rotating vector, carrier frequency image tracking techniques to reliably identify and track the orientation of the d and q axes even when the rotor is at standstill. However, additional details in the saliency image must be used to identify the polarization of the magnets in order to distinguish the north and south poles. The magnet polarity is identified by using magnetic saturation effects on the saliency image to uniquely identify the magnet pole polarity being tracked. Experimental results show that the algorithms are capable of reliable and fast initial position estimation.

   Analysis of the influence of converter non-linearities on performance of sensorless controlled synchronous PM machine algorithms
By R. Filka; G. M. Asher; P. Wheeler; C. Silva [View]
[Download]

Abstract: This paper presents a modelling analysis of three-phase converter non-linearities and their effect on sensorless motor control algorithms. Several factors contributing to converter non-linearities are investigated and their relative importance for the sensorless algorithm ascertained. The study was carried out using Saber simulation software, which allows very accurate simulation of the switching behaviour of the converter. Use of simulation allows the investigation of the importance of individual factors. The paper shows that the most dominant factors contributing to converter non-linearities are that of dead-time and device voltage drop. Furthermore different dead-time and voltage drop compensation strategy are presented. Simulation results prove the necessity of using compensation strategies to improve the performance of the sensorless control. Experimental results are presented to illustrate the validity of the analysis.

   Influence of motor parameter errors to properties of PMSM sensorless drive with speed and position observers
By M. Lec; T. Orlowska-Kowalska [View]
[Download]

Abstract: The paper deals with the analysis of PMSM drive system with different speed and position observers. Three methods of speed and position estimation were described and compared. The first method is based on voltage differential equations of PMSM and the second one uses the reduced-order observer of Luenberger type. The third method uses the full-order extended observer The mathemati-cal model of the vector-controlled drive system in Matlab-Simulink was used for simulation. All the estimation methods were compared and evaluated from the point of view of model sensitivity to the stator parameter changes and the less sensitive methods were tested in the experimental vector con-trolled PMSM drive system. Average speed and position estimation errors as well as dynamical prop-erties of the simulated and real drive system were tested and evaluated in the presence of errors of motor parameter used in the estimator models.

EPE 2003 - Topic 07d: Sensorless Techniques
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2003 - Conference > EPE 2003 - Topic 07: MEASUREMENTS AND SENSORS > EPE 2003 - Topic 07d: Sensorless Techniques
	[return to parent folder]

	Self-sensing active magnetic bearings using a new PWM amplifier equiped with a bias voltage source By T. Yoshida; Y. Kuroba; K. Ohniwa; O. Miyashita	[View] [Download]
Abstract: In this paper, a self-sensing active magnetic bearing (AMB) with a new PWM amplifier is proposed. This amplifier employs two DC sources: one supplies a control current and the other supplies a bias current. A pair of electromagnets driven by this amplifier also works as a position sensor based on bridge measurement. In the experiment, a rotor running at 45,000 min-1 is suspended by the proposed 5-axis AMB without any position sensors. The experimental system is still stable even if the length of the cables between the PWM amplifiers and the electromagnets is varied within 45 meters.

	Model-based speed identification for induction machines in the whole operating range By M. Depenbrock; C. Evers	[View] [Download]
Abstract: A speed observer for induction machines without rotational transducers is presented. In contrast to known adaptive observer strategies, the proposed scheme uses the conventional current difference and a new stretch-twist operator to avoid the known instability region and to obtain a constant gain additionally. Furthermore a parasitic dc-component elimination is presented to ensure operation with very low stator frequencies. Characteristics are explained and verified by measurements.

	Optimization of saliency effects of external rotor permanent magnet synchronous motors with respect to enhanced INFORM-capability for sensorless control By U.H. Rieder; M. Schroedl	[View] [Download]
Abstract: In many applications like traction, starter generators, and direct drives the need for high torque is the basic issue. This paper presents the combination of advantages of external rotor PMSMs and sensorless control algorithms, especially for low speed using the INFORM-method (Indirect Flux Detection by Online Reactance Measurement). Therefore saliency and saturation effects have to be taken into consideration and can be enforced for improved INFORM performance.

	Nonlinear state-observer techniques for sensorless control of automotive PMSM’s, including load-torque estimation and saliency By B.S. Bhangu; C.M. Bingham	[View] [Download]
Abstract: The paper investigates various non-linear observer-based rotor position estimation schemes for sensorless control of permanent magnet synchronous motors (PMSMs). Attributes of particular importance to the application of brushless motors in the automotive sector, are considered e.g. implementation cost, accuracy of predictions during load transients, the impact of motor saliency and algorithm complexity. Emphasis is given to techniques based on model linearisation during each sampling period (EKF); feedback-linearisation followed by Luenberger observer design based on the resulting ‘linear’ motor characteristics; and direct design of non-linear observers. Although the benefits of sensorless commutation of PMSMs have been well expounded in the literature, an integrated approach to their design for application to salient machines subject to load torque transients remains outstanding. Furthermore, this paper shows that the inherent characteristics of some non-linear observer structures are particularly attractive since they provide a phase-locked-loop (PLL)-type of configuration that can encourage stable rotor position estimation, thereby enhancing the overall sensorless scheme. Moreover, experimental results show how operation through, and from, zero speed, is readily obtainable. Experimental results are also employed to demonstrate the attributes of each methodology, and provide dynamic and computational performance comparisons.

	Anisotropy in induction machine lamination and its influence on mechanical sensorless control and condition monitoring By T. M. Wolbank; J. L. Machl; H. Hauser; P. Macheiner	[View] [Download]
Abstract: In the application of inverter-fed ac-machines, the lamination material used shows - despite of all assumptions - not too little material anisotropy effects. Since the sheets have a sufficiently small thickness and are manufactured by a rolling and punching process, they meet all physical requirements to show anisotropic distribution of the crystalline energy. The effect is smaller than known for the grain-oriented steels applied in transformers, however is still observable, as measurements on lamination material specimen will show. Lamination material anisotropy has mostly been neglected up to now, because the fundamental wave behaviour of induction machines is only negligible influenced. Although this effect is only visible in the transient electrical behaviour, in some cases it has to be considered to ensure proper function and high dynamics of sensorless controlled ac-drives. However, not only mechanical sensorless control but also condition monitoring schemes for acmachines evaluate this transient electrical behaviour and thus the lamination material anisotropy effects are of great importance in these fields.

	Robust observer for sensorless control of synchronous drive with uncertain parameters By L. Peyras; S. Caux; M. Fadel	[View] [Download]
Abstract: This paper presents a robust observer based on redundancy computing emf on 2 axis rotor oriented reference frame. the first step is a stalling phase avoiding any wrong rotation whatever the rotor initial position is. The second step is a calibration phase, to estimate accurately the electrical parametres of the drive. Using the first two steps, we finally control the sensorless drive by estimating emf, velocity and position which are quite close to reality only by voltage and current measurements.

	Precision improvement of IPM motor position sensorless control with PWM inverter carrier frequency component method By J. Oyama; T. Higuchi; T. Abe; D. Itoyama; M. Mamo	[View] [Download]
Abstract: We proposed carrier frequency component method (CFCM) for position sensor-less control of IPM motor, in which we utilized carrier frequency component current of PWM inverter as the motor position information source. In this paper, we present a compensation method to improve the accuracy of CFCM position estimation. In the experiments, the motor has been successfully controlled from zero speed to 1,350rpm without mechanical sensor.

	Wide bandwidth sensorless position control using a superimposed synchronous test signal By H.G. Köpken	[View] [Download]
Abstract: Sensorless servo control requires fast, on-line rotor position estimation during standstill. This paper presents a way to calculate a position estimate in every PWM cycle. It uses a test signal with full PWM frequency. A decoupling algorithm eliminates the effect of fast current changes on the position estimates. Measurements of position command tracking and transient load behaviour are shown.

	Hybrid sensorless position observation of a brushless DC motor By S. Grainger; M. Allan	[View] [Download]
Abstract: Hybrid schemes offer the possibility of improved performance over existing schemes through the combination of desirable features from multiple technologies. A hybrid system is developed for the estimation of rotor position within brushless DC motors (BLDCM). This comprises a sliding mode observer for parameter robustness, a modified integrator for drift free operation under bias conditions and an artificial neural network (ANN) for data fusion and mapping functions. Results show the system to be extremely robust and to have good accuracy.

	Initial rotor position estimation for an integrated starter alternator IPM synchronous machine By H. Kim; K.-K. Huh; M. Harke; J. Wai; R. D. Lorenz; T. M. Jahns	[View] [Download]
Abstract: Novel methods for initial position estimation during start-up are presented for an integrated starter alternator interior permanent magnet synchronous machine. The magnet cavities in the IPMSM rotor create a sizable difference in the inductances of the two orthogonal rotor axes. This spatial saliency base on the rotor position makes it possible to use persistent, rotating vector, carrier frequency image tracking techniques to reliably identify and track the orientation of the d and q axes even when the rotor is at standstill. However, additional details in the saliency image must be used to identify the polarization of the magnets in order to distinguish the north and south poles. The magnet polarity is identified by using magnetic saturation effects on the saliency image to uniquely identify the magnet pole polarity being tracked. Experimental results show that the algorithms are capable of reliable and fast initial position estimation.

	Analysis of the influence of converter non-linearities on performance of sensorless controlled synchronous PM machine algorithms By R. Filka; G. M. Asher; P. Wheeler; C. Silva	[View] [Download]
Abstract: This paper presents a modelling analysis of three-phase converter non-linearities and their effect on sensorless motor control algorithms. Several factors contributing to converter non-linearities are investigated and their relative importance for the sensorless algorithm ascertained. The study was carried out using Saber simulation software, which allows very accurate simulation of the switching behaviour of the converter. Use of simulation allows the investigation of the importance of individual factors. The paper shows that the most dominant factors contributing to converter non-linearities are that of dead-time and device voltage drop. Furthermore different dead-time and voltage drop compensation strategy are presented. Simulation results prove the necessity of using compensation strategies to improve the performance of the sensorless control. Experimental results are presented to illustrate the validity of the analysis.

	Influence of motor parameter errors to properties of PMSM sensorless drive with speed and position observers By M. Lec; T. Orlowska-Kowalska	[View] [Download]
Abstract: The paper deals with the analysis of PMSM drive system with different speed and position observers. Three methods of speed and position estimation were described and compared. The first method is based on voltage differential equations of PMSM and the second one uses the reduced-order observer of Luenberger type. The third method uses the full-order extended observer The mathemati-cal model of the vector-controlled drive system in Matlab-Simulink was used for simulation. All the estimation methods were compared and evaluated from the point of view of model sensitivity to the stator parameter changes and the less sensitive methods were tested in the experimental vector con-trolled PMSM drive system. Average speed and position estimation errors as well as dynamical prop-erties of the simulated and real drive system were tested and evaluated in the presence of errors of motor parameter used in the estimator models.