EPE Association: EPE 1999 - Topic 05b: Reluctance Drives

EPE 1999 - Topic 05b: Reluctance Drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1999 - Conference > EPE 1999 - Topic 05: ELECTRICAL MACHINES AND ADJUSTABLE SPEED DRIVES > EPE 1999 - Topic 05b: Reluctance Drives

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   A Novel Two-Phase Switched Reluctance Machine for Low Torque Ripple
By Z. Zhao; L. Yuan; J. Jiang [View]
[Download]

Abstract: A novel two-phase switched reluctance machine (SRM) is presented, that has performance characteristics of a four-phase machine. The new machine maintains the simple two-phase operation while improving the torque ripple and energy circulation associated with conventional switched reluctance machines. The proposed rotor structure, stator winding configuration and operating principle is introduced. Computer simulation based on a non-saturable model is developed. Finite element analysis is employed to confirm the magnitude of improvement.

   Acoustic Noise Simulation for Switched Reluctance Motors with Audible output
By P. O. Rasmussen; F. Blaabjerg; J. K. Pedersen; P. C. Kjaer; T. J. E. Miller [View]
[Download]

Abstract: Acoustic noise in switched reluctance motors is one of the last problems which have to be solved before a more widespread use will come. In order to design a low noise Switched Reluctance Motor drive, simulation tools are needed, and this paper describes a design programme where acoustic noise of electromagnetic origin can be estimated and even be heard by the motor-designer. The design program is based on a new, simple developed vibrational and acoustic model where the parameters can be calculated based on the geometry of the motor. The vibrational and acoustic model is verified in both time and frequency domain where vibrations and acoustic noise have been considered

   An Integrated Single-Phase Power-Factor-Controlled Switched Reluctance Motor drive with Minimum of Passive Components
By G. K. Andersen; L. Helle; P. O. Rasmussen [View]
[Download]

Abstract: A low-cost and integrated Adjustable Speed Drive with near unity input power factor is presented. The motor is a two phase Switched Reluctance Motor and the power factor correction circuit is a single phase boost rectier. The power factor correction inductance (the boost inductance) is integrated into the motor. The drive is controlled in order to equal the power drawn from the dc- link to the input power drawn from the line sup- ply. As a consequense of this control strategy, the need for energy storage in the dc-link is near zero. Experimental results veries the functionality and the performance of this new drive topology.

   Comparative Evaluation of Torque/Radial Force for SR Motors
By M. Sanada; Y. Takeda; T. Kosaka; N. Matsui [View]
[Download]

Abstract: Although the switched reluctance motor has many features, the relatively large torque ripple and acoustic noise are major disadvantages. Many reports have been published on the torque ripple reduction but only few papers have been published on the acoustic noise reduction. The acoustic noise of the switched reluctance motor is generated by the stator deformation due to the radial force generated by excitation. The paper deals with a comparative study of switched reluctance motors from the standpoint of the maximum torque/radial force ratio. The comparative studies are based on the FEM analysis and experimental verification. Three types of stator/rotor teeth combinations, 12/8, 8/6 and 6/4 are selected for comparisons and each type is optimally designed to obtain the maximum torque/radial force ratio under the same stator outer diameter, gap length and excitation per pole. The 12/8 combination has proved to give the best performance among them.

   Control Aspects of Brushless Doubly Fed Reluctance Machines
By R.E. Betz; M.G. Jovanovic [View]
[Download]

Abstract: The Brushless Doubly Fed Reluctance Machine (BDFRM) is a form of slip recovery machine that does not require brushes. Because of its slip recovery nature it allows smaller inverters to be used if the speed range is limited. Therefore in many applications it may allow a lower system cost. This paper will present a theoretical analysis of several control strategies for this machine when supplied by an inverter.

   Electronic Cancellation of Acoustic Noise in a Fan System Driven by a Switched Reluctance Motor
By M. Brackley; Ch. Pollock [View]
[Download]

Abstract: An electronic technique, originally developed for the cancellation of stator vibration in the switched reluctance motor, has been applied to reduce acoustic noise generated by part of a fan/blower system which is remote from the motor. When a single phase switched reluctance motor was coupled to a hand dryer it was found that the excitation of the motor induced acoustic noise from the fan housing at the natural resonant frequency of the housing. The electronic cancellation technique was then applied to the motor commutation control producing two opposing vibrations in the fan housing which had a cancelling effect, inhibiting the excitation of the resonance. This resulted in a 10dB reduction in the magnitude of vibration of the housing at its mechanical resonant frequency, and significantly reduced the audible acoustic noise generated by the resonance as perceived by the user.

   Flux-Linkage Control of Fully-Pitched Switched Reluctance Motors
By C. Weiner; A.G. Jack; P.P. Acarnley; B.C. Mecrow [View]
[Download]

Abstract: This paper describes the flux-linkage control of a fully-pitched winding Switched Reluctance Motor (SRM) connected in delta to a standard three-phase bridge inverter. The control principle is explained and practical flux-linkage and current waveforms are shown. High quality control behaviour is achieved for the whole operating range of the drive.

   Generator Operation of a Switched Reluctance Machine Drive for Electric Vehicles
By R. Inderka; M. Menne; R. W. De Doncker [View]
[Download]

Abstract: This paper deals with the generator operation of a switched reluctance drive for an electric vehicle (EV) application. In EV applications, operation in generating mode over a wide torque-speed range, i.e., in chopping mode as well as in single-pulse operation, is required. In addition, the DC-link voltage is specified for a wide operating range which leads to stringent control requirements the switched reluctance drive. In this paper, a novel control strategy to implement a three-level hysteresis current control in generating mode is presented. Improved drivve efficiency was obtained with this technique. The sets of parameters, which are necessary for the control of a switched reluctance drive, and the resulting efficiency characteristics are presented. In single pulse mode with a high back EMF uncontrollable overcurrents during generating mode can occur. To protect the drive against this chatacteristic behavior and the resulting uncontrolable torque pulsation, suitable control strategies are presented.

   Implementation of Closed-Loop Controllers for Switched Reluctance Drives on Microcontrollers and DSP Controllers
By B. Hexamer [View]
[Download]

Abstract: Modern microcontrollers and DSP controllers especially ease due to their integrated peripherals the implementation of closed-loop control for a.c. induction, synchronous and brushless d.c. motors. The non-linear, time-variant behaviour and the discrete (switched) working principle of the switched reluctance motor also demands the implementation of closed-loop speed and torque control on microcontrollers and DSP controllers. Although control algorithms totally differ between an a.c. motor and a switched reluctance motor, the same plant parameters like rotor speed and position for example are necessary for optimum operation. Based on the different control principles and the methods for measuring the electrical and mechanical plant parameters of a switched reluctance motor, an ideal control unit will therefore be defined. This device will be compared to several standard microcontrollers and DSP controllers to examine the suitability of such integrated circuits for the control of switched reluctance drives.

   Inverse Modelling for Satured Synchronous Reluctance Motors or Permanent Magnet Synchronous Motors
By G. Sturtzer; D. Flieller; J.-P. Louis; M. Gabsi [View]
[Download]

Abstract: This paper presents a new method, well suited to synchronous reluctance motors or permanent magnet motors, which allows to create the stator currents which lead to a constant instantaneous electromagnetic torque. This method takes into account the saturation of the magnetic circuit. It comes from the properties of constant torque curves in the Concordia's reference frame. We also introduce the experimental method to obtain directly the constant torque curves.

   Multi-dimensional Non-linear Lumped Magnetic Parameter Circuit for Dynamic Modelling of Mutual Coupling and Faults in Switched Reluctance Motors
By T. Sawata; P.C. Kjaer; J.J. Bremner; C. Cossar; T.J.E. Miller; J.R. Coles; G. White [View]
[Download]

Abstract: Several of the applications for which the switched reluctance motor (SRM) is considered a serious contender require electromagnetic models that allow dy- namic simulation of phase interaction arising from mutual coupling, winding failures, inverter failures or mechanical imperfections such as rotor eccentricity. The commonly used superposition of single-phase magnetisation data does not allow such a drive analysis. Magnetic equivalent cir- cuits have been proposed to simulate these phenomena, but great diculty is encountered when attempting to represent the airgap and rotor/stator pole-tip permeances analytically and independent of each other. This paper proposes a new method to represent the SRM accurately using a lumped parameter, magnetic equivalent circuit which overcomes the aforementioned diculties. Simula- tions under turns short-circuit faults were carried out and the results were compared with the time-stepping FEA. Various simulation results under faults were also analysed. It shows the eects of the fault on the performance and demonstrates the feasibility of the new approach.

   Rotating Vector Methods for Analysis and Control for Smooth Torque and Self-Sensing Motion Control of Switched Reluctance Motor Drives
By N.J. Nagel; R. D. Lorenz [View]
[Download]

Abstract: This paper presents a novel method of modeling and control of a switched reluctance motor (SRM). It is shown that complex rotating vectors can be used to develop an equivalent form of the torque equation in the SRM. This equivalent form of the torque equation leads to an insightful development of a closed form solution of the currents necessary to produce smooth torque in an SRM given any rotor dependent inductance function. The concept of rotating vectors is also used for saliency based position estimation techniques.

   Speed Estimator for Induction Motor
By Y. Shrivastava; M. T. Nguyen; S. Sathiakumar [View]
[Download]

Abstract: A novel technique of speed estimation for an induction motor is presented in this paper. The technique does not employ computationally expensive algorithms such as Model Reference System or Speed Adaptive Flux System, in which estimation accuracy is influenced by chosen parameters of the adaption mechanism. In the proposed algorithm, speed of the motor is calculated based on the dynamic model of the motor and an observer estimates rotor flux required for speed calculation. It does not require any start up procedure. Simulation and experimental evidence suggests that the algorithm works well with any initial conditions.

   SRM Drive Modelling Taking Into Account Saturation Effect
By H. Sahraoui; H. Zeroug [View]
[Download]

Abstract: In this paper, we present a numerical method, which combines the electromagnetic model of the SRM and that of the circuit supply. In this approach, the finite elements method is used to determine the characteristic of the machine, considering the non-linearity of the material and that of the structure of the machine. The machine parameters are used to develop and assess two SRM models. The first model uses a linear electromagnetic characteristic, whereas the second takes into account the saturation effect. The simulation results show that the non-linear model is more accurate for torquen ripple assesment. In the non-linear model, the average torque and its harmonic content are affected by the saturation level. The method described in this paper could be used to design a high performance SRM drive, prior to any further optimisation.

EPE 1999 - Topic 05b: Reluctance Drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1999 - Conference > EPE 1999 - Topic 05: ELECTRICAL MACHINES AND ADJUSTABLE SPEED DRIVES > EPE 1999 - Topic 05b: Reluctance Drives
	[return to parent folder]

	A Novel Two-Phase Switched Reluctance Machine for Low Torque Ripple By Z. Zhao; L. Yuan; J. Jiang	[View] [Download]
Abstract: A novel two-phase switched reluctance machine (SRM) is presented, that has performance characteristics of a four-phase machine. The new machine maintains the simple two-phase operation while improving the torque ripple and energy circulation associated with conventional switched reluctance machines. The proposed rotor structure, stator winding configuration and operating principle is introduced. Computer simulation based on a non-saturable model is developed. Finite element analysis is employed to confirm the magnitude of improvement.

	Acoustic Noise Simulation for Switched Reluctance Motors with Audible output By P. O. Rasmussen; F. Blaabjerg; J. K. Pedersen; P. C. Kjaer; T. J. E. Miller	[View] [Download]
Abstract: Acoustic noise in switched reluctance motors is one of the last problems which have to be solved before a more widespread use will come. In order to design a low noise Switched Reluctance Motor drive, simulation tools are needed, and this paper describes a design programme where acoustic noise of electromagnetic origin can be estimated and even be heard by the motor-designer. The design program is based on a new, simple developed vibrational and acoustic model where the parameters can be calculated based on the geometry of the motor. The vibrational and acoustic model is verified in both time and frequency domain where vibrations and acoustic noise have been considered

	An Integrated Single-Phase Power-Factor-Controlled Switched Reluctance Motor drive with Minimum of Passive Components By G. K. Andersen; L. Helle; P. O. Rasmussen	[View] [Download]
Abstract: A low-cost and integrated Adjustable Speed Drive with near unity input power factor is presented. The motor is a two phase Switched Reluctance Motor and the power factor correction circuit is a single phase boost rectier. The power factor correction inductance (the boost inductance) is integrated into the motor. The drive is controlled in order to equal the power drawn from the dc- link to the input power drawn from the line sup- ply. As a consequense of this control strategy, the need for energy storage in the dc-link is near zero. Experimental results veries the functionality and the performance of this new drive topology.

	Comparative Evaluation of Torque/Radial Force for SR Motors By M. Sanada; Y. Takeda; T. Kosaka; N. Matsui	[View] [Download]
Abstract: Although the switched reluctance motor has many features, the relatively large torque ripple and acoustic noise are major disadvantages. Many reports have been published on the torque ripple reduction but only few papers have been published on the acoustic noise reduction. The acoustic noise of the switched reluctance motor is generated by the stator deformation due to the radial force generated by excitation. The paper deals with a comparative study of switched reluctance motors from the standpoint of the maximum torque/radial force ratio. The comparative studies are based on the FEM analysis and experimental verification. Three types of stator/rotor teeth combinations, 12/8, 8/6 and 6/4 are selected for comparisons and each type is optimally designed to obtain the maximum torque/radial force ratio under the same stator outer diameter, gap length and excitation per pole. The 12/8 combination has proved to give the best performance among them.

	Control Aspects of Brushless Doubly Fed Reluctance Machines By R.E. Betz; M.G. Jovanovic	[View] [Download]
Abstract: The Brushless Doubly Fed Reluctance Machine (BDFRM) is a form of slip recovery machine that does not require brushes. Because of its slip recovery nature it allows smaller inverters to be used if the speed range is limited. Therefore in many applications it may allow a lower system cost. This paper will present a theoretical analysis of several control strategies for this machine when supplied by an inverter.

	Electronic Cancellation of Acoustic Noise in a Fan System Driven by a Switched Reluctance Motor By M. Brackley; Ch. Pollock	[View] [Download]
Abstract: An electronic technique, originally developed for the cancellation of stator vibration in the switched reluctance motor, has been applied to reduce acoustic noise generated by part of a fan/blower system which is remote from the motor. When a single phase switched reluctance motor was coupled to a hand dryer it was found that the excitation of the motor induced acoustic noise from the fan housing at the natural resonant frequency of the housing. The electronic cancellation technique was then applied to the motor commutation control producing two opposing vibrations in the fan housing which had a cancelling effect, inhibiting the excitation of the resonance. This resulted in a 10dB reduction in the magnitude of vibration of the housing at its mechanical resonant frequency, and significantly reduced the audible acoustic noise generated by the resonance as perceived by the user.

	Flux-Linkage Control of Fully-Pitched Switched Reluctance Motors By C. Weiner; A.G. Jack; P.P. Acarnley; B.C. Mecrow	[View] [Download]
Abstract: This paper describes the flux-linkage control of a fully-pitched winding Switched Reluctance Motor (SRM) connected in delta to a standard three-phase bridge inverter. The control principle is explained and practical flux-linkage and current waveforms are shown. High quality control behaviour is achieved for the whole operating range of the drive.

	Generator Operation of a Switched Reluctance Machine Drive for Electric Vehicles By R. Inderka; M. Menne; R. W. De Doncker	[View] [Download]
Abstract: This paper deals with the generator operation of a switched reluctance drive for an electric vehicle (EV) application. In EV applications, operation in generating mode over a wide torque-speed range, i.e., in chopping mode as well as in single-pulse operation, is required. In addition, the DC-link voltage is specified for a wide operating range which leads to stringent control requirements the switched reluctance drive. In this paper, a novel control strategy to implement a three-level hysteresis current control in generating mode is presented. Improved drivve efficiency was obtained with this technique. The sets of parameters, which are necessary for the control of a switched reluctance drive, and the resulting efficiency characteristics are presented. In single pulse mode with a high back EMF uncontrollable overcurrents during generating mode can occur. To protect the drive against this chatacteristic behavior and the resulting uncontrolable torque pulsation, suitable control strategies are presented.

	Implementation of Closed-Loop Controllers for Switched Reluctance Drives on Microcontrollers and DSP Controllers By B. Hexamer	[View] [Download]
Abstract: Modern microcontrollers and DSP controllers especially ease due to their integrated peripherals the implementation of closed-loop control for a.c. induction, synchronous and brushless d.c. motors. The non-linear, time-variant behaviour and the discrete (switched) working principle of the switched reluctance motor also demands the implementation of closed-loop speed and torque control on microcontrollers and DSP controllers. Although control algorithms totally differ between an a.c. motor and a switched reluctance motor, the same plant parameters like rotor speed and position for example are necessary for optimum operation. Based on the different control principles and the methods for measuring the electrical and mechanical plant parameters of a switched reluctance motor, an ideal control unit will therefore be defined. This device will be compared to several standard microcontrollers and DSP controllers to examine the suitability of such integrated circuits for the control of switched reluctance drives.

	Inverse Modelling for Satured Synchronous Reluctance Motors or Permanent Magnet Synchronous Motors By G. Sturtzer; D. Flieller; J.-P. Louis; M. Gabsi	[View] [Download]
Abstract: This paper presents a new method, well suited to synchronous reluctance motors or permanent magnet motors, which allows to create the stator currents which lead to a constant instantaneous electromagnetic torque. This method takes into account the saturation of the magnetic circuit. It comes from the properties of constant torque curves in the Concordia's reference frame. We also introduce the experimental method to obtain directly the constant torque curves.

	Multi-dimensional Non-linear Lumped Magnetic Parameter Circuit for Dynamic Modelling of Mutual Coupling and Faults in Switched Reluctance Motors By T. Sawata; P.C. Kjaer; J.J. Bremner; C. Cossar; T.J.E. Miller; J.R. Coles; G. White	[View] [Download]
Abstract: Several of the applications for which the switched reluctance motor (SRM) is considered a serious contender require electromagnetic models that allow dy- namic simulation of phase interaction arising from mutual coupling, winding failures, inverter failures or mechanical imperfections such as rotor eccentricity. The commonly used superposition of single-phase magnetisation data does not allow such a drive analysis. Magnetic equivalent cir- cuits have been proposed to simulate these phenomena, but great diculty is encountered when attempting to represent the airgap and rotor/stator pole-tip permeances analytically and independent of each other. This paper proposes a new method to represent the SRM accurately using a lumped parameter, magnetic equivalent circuit which overcomes the aforementioned diculties. Simula- tions under turns short-circuit faults were carried out and the results were compared with the time-stepping FEA. Various simulation results under faults were also analysed. It shows the eects of the fault on the performance and demonstrates the feasibility of the new approach.

	Rotating Vector Methods for Analysis and Control for Smooth Torque and Self-Sensing Motion Control of Switched Reluctance Motor Drives By N.J. Nagel; R. D. Lorenz	[View] [Download]
Abstract: This paper presents a novel method of modeling and control of a switched reluctance motor (SRM). It is shown that complex rotating vectors can be used to develop an equivalent form of the torque equation in the SRM. This equivalent form of the torque equation leads to an insightful development of a closed form solution of the currents necessary to produce smooth torque in an SRM given any rotor dependent inductance function. The concept of rotating vectors is also used for saliency based position estimation techniques.

	Speed Estimator for Induction Motor By Y. Shrivastava; M. T. Nguyen; S. Sathiakumar	[View] [Download]
Abstract: A novel technique of speed estimation for an induction motor is presented in this paper. The technique does not employ computationally expensive algorithms such as Model Reference System or Speed Adaptive Flux System, in which estimation accuracy is influenced by chosen parameters of the adaption mechanism. In the proposed algorithm, speed of the motor is calculated based on the dynamic model of the motor and an observer estimates rotor flux required for speed calculation. It does not require any start up procedure. Simulation and experimental evidence suggests that the algorithm works well with any initial conditions.

	SRM Drive Modelling Taking Into Account Saturation Effect By H. Sahraoui; H. Zeroug	[View] [Download]
Abstract: In this paper, we present a numerical method, which combines the electromagnetic model of the SRM and that of the circuit supply. In this approach, the finite elements method is used to determine the characteristic of the machine, considering the non-linearity of the material and that of the structure of the machine. The machine parameters are used to develop and assess two SRM models. The first model uses a linear electromagnetic characteristic, whereas the second takes into account the saturation effect. The simulation results show that the non-linear model is more accurate for torquen ripple assesment. In the non-linear model, the average torque and its harmonic content are affected by the saturation level. The method described in this paper could be used to design a high performance SRM drive, prior to any further optimisation.