EPE Association: EPE 1991 - 08 - Session 1.8: SWITCHED AND VARIABLE RELUCTANCE MOTOR DRIVES

EPE 1991 - 08 - Session 1.8: SWITCHED AND VARIABLE RELUCTANCE MOTOR DRIVES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 08 - Session 1.8: SWITCHED AND VARIABLE RELUCTANCE MOTOR DRIVES

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   PREDICTION OF STATIC MAGNETISATION CHARACTERISTICS OF SWlTCHED RELUCTANCE MOTORS FOR GENERAL ROTOR POSlTlONS
By Jawad Faiz [View]
[Download]

Abstract: In the present paper it is briefly shown that there is a possitilily of extending the permeance method to a more general design method of the switched reluctance motors in which a square wave voltage is applied and current waveform efficiency and other required performance parameters are determined. The extension of the present work could be used to examine the effects of the combination of structural and operating conditions of SRMS.

   COMPUTER ANALYSIS OF DRIVE SYSTEMS FOR THE SWITCHED RELUCTANCE MOTOR
By H. Zelaya-de la Parra; ç. Elmas [View]
[Download]

Abstract: The paper deals with the analysis of 4 type of drives for switched reluctance motors (SRM) using a simulator developed in 'C' language for personal computers. The state-space equations for the whole system (Drive+SRM) are solved numerically using the Runge-Kutta method, providing information of the motor performance during low and high speeds. Special attention is given to the analysis of harmonics in the current waveforms, as well as to the output torque ripple. The paper shows the main characterisation of the current-fed and voltage-fed drives and suggests a combination of the two types to obtain better performance of the SRM.

   MAGNETIC ANALYSIS OF A SWITCHED RELUCTANCE MOTOR USING A FINITE DIFFERENCE METHOD
By D. W. J. Pulle [View]
[Download]

Abstract: An effective switched reluctance drive simulation must be able to accommodate parameter changes to the converter as well as the motor geometry. ln the latter case a new set of magnetization curves must be generated. This paper proposes a new method capable of calculating the flux-linkage value based on user selected geometry, magnetic material and rotor angle information. Polar coordinate based none uniform finite difference node grids are assigned to the rotor and stator which are specifically suited to the switched reluctance motor geometry. The coefficient matrices for both grids are obtained using Maxwells current equation in its integral form. The node potontials for the overlapping grids are found by iteratively solving the coefficient matrix equations using a conjugate gradient method. Results obtained with the new method are compared with those found using a finite element method.

   DYNAMIC MODELLING OF SINGLY-SALIENT AND DOUBLY-SALIENT RELUCTANCE MOTOR DRIVE SYSTEMS
By H. C. Lovatt; M. L. McClelland; J. M. Stephenson [View]
[Download]

Abstract: This paper describes a computer program which models in detail singly-salient and doubly-salient, open-loop and closed-loop reluctance motor drives. The program is integrated into a larger suite of general modelling and design programs. Saturation load-dynamics and the limitations of transducers are all included in the program. Validity of the program is demonstrated by results which show a close correlation between the actual system and the modelled system. Emphasis is placed on the thoroughness or the modelling and on providing a flexible program. Object-orientated programming techniques have been used to provide the desired flexibilily.

   WIDE-BANDWIDTH TORQUE AND POWER MEASUREMENT IN RELUCTANCE MOTOR DRIVES
By M. L. McClelland; H.C. Lovatt; J .M. Stephenson [View]
[Download]

Abstract: Wide-bandwldth measurements are necessary when testing electronically switched drives. Two difficult problems are addressed: the measurement of motor phase input power at low speed with a high PWM modulation frequency and the measurement of small torque ripple (superimposed on a large mean torque), in an electrically noisy environment. Extensive use is made of digital signal processing techniques to reduce noise and ensure high accuracy. Experimental results are presented to illustrate each technique.

   Aspects of the Control of Synchronous Reluctance Machines
By R. E. Betz; T. J. E. Miller [View]
[Download]

Abstract: This report presents a theoretical performance analysis of several control strategies for synchronous reluctance machines which are being fed from a current controlled inverter. The three main control strategies considered have as their objectives to allow maximum rated torque, maximum rate of change of torque and maximum power factor respectively from the machine. These control strategies are investigated to determine their limitations and inter-relationships. A technique for "field weakened" control of the machine is developed. At lower angular velocities it is shown that the rate of change of torque performance of the control strategies based on constant current angle is poor. A control strategy based on having constant current in the most inductive axis of the machine is shown to give better performance under these conditions.

   FOUR-QUADRANT CONTROL OF A 20 W SWITCHED RELUCTANCE MOTOR DRIVE FOR NEAR SERVO APPLICATIONS
By M. J. Kamper [View]
[Download]

Abstract: The performance of a four-quadrant controlled, 12 V, 20 W switched reluctance motor is presented. The drive basically consists of a 3-phase switched reluctance motor and a converter using only 3 power electronic switches (single switch per phase). A single programmable logic array together with some mono-stable integrated circuits are used for the four-quadrant control of the drive, including conduction angle control for increasing the speed range. The advantage of the drive is the simplicity with which four-quadrant control is obtained. However, it is shown that the power density of such a small switched reluctance machine (small in diameter) is low compared to machines with permanent magnet excitiation.

   ACCURATE SENSORLESS ROTOR POSITION DETECTION IN AN SR MOTOR
By N. M. Mvungi; J. M. Stephenson [View]
[Download]

Abstract: The electronic switching of the currents in the phases of a switched reluctance motor is synchronised to the angle of rotation, usually by means of a simple shaft encoder. The authors have developed a novel scheme for eliminating this transducer by detecting rotor position from voltage and current measurements at the power converter. The paper describes the scheme, and in particular, the solution of the fundamental problem of errors caused by interference from currents in other phases.

   A NEW SWITCHED RELUCTANCE MOTOR DRIVE CONFIGURATION
By D. S. Schramm; B. W. Williams; T. C. Green [View]
[Download]

Abstract: A convertor with six semiconductor switches is used to feed a four-phase doubly-salient switched reluctance motor. The convertor circuit uses an average of one and a half switches per phase winding, with each switch rated at the supply voltage and allows the full supply voltage across each phase winding. A switching algorithm to control the switches, two of which are connected to two phases each, is described. Test results from a 4 kW IGBT convertor, four-phase switched reluctance motor drive over the speed range 0 to 2000 rpm and torque range 0 to 25 Nm, rated torque, are presented. Results include, efficiency, power losses, optimal advance and overlap angle.

   THE SWITCHED RELUCTANCE MOTOR DRIVES: CHARACTERISTICS AND PERFORMANCES
By Hassan H. Moghbelli; Muhammad H. Rashid [View]
[Download]

Abstract: Adjustable drives using the switched Reluctance Motors (SRM) are making a significant contribution to industrial applications. In some cases, the SRM drives provide equal or better performance for comparable cost and offer lower motor maintenance than brushless type motors. This paper surveys the literature of the switched reluctance motor drives, including motor design, controller circuit, performance characteristics and applications. Several applications of SRM drives are taken as examples to provide a useful guideline for comparing the SRM with different AC adjustable motor drives.

   AN INVESTIGATION OF CONTROL OF SWITCHED RELUCTANCE MOTOR SUPPLIED BY A.C. PULSES
By M. Oljaca; J. Corda [View]
[Download]

Abstract: This paper investigates the idea of supplying the switched reluctance motor with bipolar currents, obtained directly from an a.c. source (mains) which would eliminate the need for an input rectifier and a d.c. link capacitor in the electronic converter of the drive. The idea is based on the fact that the direction of the electromagnetic torque produced by a switched reluctance motor, is not dependant on the direction of the currents flowing through the motor windings. The power electronic circuit studied is suitable for use with a bifilar wound motor. It requires two switching elements and two diodes per phase. The control by position-dependant switching in the single pulse operating mode and the control by current limit In the chopping mode are investigated. It is shown that apart from having a undesirable harmonic content in the supply current the drive could be successfully controlled at lower speeds.

EPE 1991 - 08 - Session 1.8: SWITCHED AND VARIABLE RELUCTANCE MOTOR DRIVES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 08 - Session 1.8: SWITCHED AND VARIABLE RELUCTANCE MOTOR DRIVES
	[return to parent folder]

	PREDICTION OF STATIC MAGNETISATION CHARACTERISTICS OF SWlTCHED RELUCTANCE MOTORS FOR GENERAL ROTOR POSlTlONS By Jawad Faiz	[View] [Download]
Abstract: In the present paper it is briefly shown that there is a possitilily of extending the permeance method to a more general design method of the switched reluctance motors in which a square wave voltage is applied and current waveform efficiency and other required performance parameters are determined. The extension of the present work could be used to examine the effects of the combination of structural and operating conditions of SRMS.

	COMPUTER ANALYSIS OF DRIVE SYSTEMS FOR THE SWITCHED RELUCTANCE MOTOR By H. Zelaya-de la Parra; ç. Elmas	[View] [Download]
Abstract: The paper deals with the analysis of 4 type of drives for switched reluctance motors (SRM) using a simulator developed in 'C' language for personal computers. The state-space equations for the whole system (Drive+SRM) are solved numerically using the Runge-Kutta method, providing information of the motor performance during low and high speeds. Special attention is given to the analysis of harmonics in the current waveforms, as well as to the output torque ripple. The paper shows the main characterisation of the current-fed and voltage-fed drives and suggests a combination of the two types to obtain better performance of the SRM.

	MAGNETIC ANALYSIS OF A SWITCHED RELUCTANCE MOTOR USING A FINITE DIFFERENCE METHOD By D. W. J. Pulle	[View] [Download]
Abstract: An effective switched reluctance drive simulation must be able to accommodate parameter changes to the converter as well as the motor geometry. ln the latter case a new set of magnetization curves must be generated. This paper proposes a new method capable of calculating the flux-linkage value based on user selected geometry, magnetic material and rotor angle information. Polar coordinate based none uniform finite difference node grids are assigned to the rotor and stator which are specifically suited to the switched reluctance motor geometry. The coefficient matrices for both grids are obtained using Maxwells current equation in its integral form. The node potontials for the overlapping grids are found by iteratively solving the coefficient matrix equations using a conjugate gradient method. Results obtained with the new method are compared with those found using a finite element method.

	DYNAMIC MODELLING OF SINGLY-SALIENT AND DOUBLY-SALIENT RELUCTANCE MOTOR DRIVE SYSTEMS By H. C. Lovatt; M. L. McClelland; J. M. Stephenson	[View] [Download]
Abstract: This paper describes a computer program which models in detail singly-salient and doubly-salient, open-loop and closed-loop reluctance motor drives. The program is integrated into a larger suite of general modelling and design programs. Saturation load-dynamics and the limitations of transducers are all included in the program. Validity of the program is demonstrated by results which show a close correlation between the actual system and the modelled system. Emphasis is placed on the thoroughness or the modelling and on providing a flexible program. Object-orientated programming techniques have been used to provide the desired flexibilily.

	WIDE-BANDWIDTH TORQUE AND POWER MEASUREMENT IN RELUCTANCE MOTOR DRIVES By M. L. McClelland; H.C. Lovatt; J .M. Stephenson	[View] [Download]
Abstract: Wide-bandwldth measurements are necessary when testing electronically switched drives. Two difficult problems are addressed: the measurement of motor phase input power at low speed with a high PWM modulation frequency and the measurement of small torque ripple (superimposed on a large mean torque), in an electrically noisy environment. Extensive use is made of digital signal processing techniques to reduce noise and ensure high accuracy. Experimental results are presented to illustrate each technique.

	Aspects of the Control of Synchronous Reluctance Machines By R. E. Betz; T. J. E. Miller	[View] [Download]
Abstract: This report presents a theoretical performance analysis of several control strategies for synchronous reluctance machines which are being fed from a current controlled inverter. The three main control strategies considered have as their objectives to allow maximum rated torque, maximum rate of change of torque and maximum power factor respectively from the machine. These control strategies are investigated to determine their limitations and inter-relationships. A technique for "field weakened" control of the machine is developed. At lower angular velocities it is shown that the rate of change of torque performance of the control strategies based on constant current angle is poor. A control strategy based on having constant current in the most inductive axis of the machine is shown to give better performance under these conditions.

	FOUR-QUADRANT CONTROL OF A 20 W SWITCHED RELUCTANCE MOTOR DRIVE FOR NEAR SERVO APPLICATIONS By M. J. Kamper	[View] [Download]
Abstract: The performance of a four-quadrant controlled, 12 V, 20 W switched reluctance motor is presented. The drive basically consists of a 3-phase switched reluctance motor and a converter using only 3 power electronic switches (single switch per phase). A single programmable logic array together with some mono-stable integrated circuits are used for the four-quadrant control of the drive, including conduction angle control for increasing the speed range. The advantage of the drive is the simplicity with which four-quadrant control is obtained. However, it is shown that the power density of such a small switched reluctance machine (small in diameter) is low compared to machines with permanent magnet excitiation.

	ACCURATE SENSORLESS ROTOR POSITION DETECTION IN AN SR MOTOR By N. M. Mvungi; J. M. Stephenson	[View] [Download]
Abstract: The electronic switching of the currents in the phases of a switched reluctance motor is synchronised to the angle of rotation, usually by means of a simple shaft encoder. The authors have developed a novel scheme for eliminating this transducer by detecting rotor position from voltage and current measurements at the power converter. The paper describes the scheme, and in particular, the solution of the fundamental problem of errors caused by interference from currents in other phases.

	A NEW SWITCHED RELUCTANCE MOTOR DRIVE CONFIGURATION By D. S. Schramm; B. W. Williams; T. C. Green	[View] [Download]
Abstract: A convertor with six semiconductor switches is used to feed a four-phase doubly-salient switched reluctance motor. The convertor circuit uses an average of one and a half switches per phase winding, with each switch rated at the supply voltage and allows the full supply voltage across each phase winding. A switching algorithm to control the switches, two of which are connected to two phases each, is described. Test results from a 4 kW IGBT convertor, four-phase switched reluctance motor drive over the speed range 0 to 2000 rpm and torque range 0 to 25 Nm, rated torque, are presented. Results include, efficiency, power losses, optimal advance and overlap angle.

	THE SWITCHED RELUCTANCE MOTOR DRIVES: CHARACTERISTICS AND PERFORMANCES By Hassan H. Moghbelli; Muhammad H. Rashid	[View] [Download]
Abstract: Adjustable drives using the switched Reluctance Motors (SRM) are making a significant contribution to industrial applications. In some cases, the SRM drives provide equal or better performance for comparable cost and offer lower motor maintenance than brushless type motors. This paper surveys the literature of the switched reluctance motor drives, including motor design, controller circuit, performance characteristics and applications. Several applications of SRM drives are taken as examples to provide a useful guideline for comparing the SRM with different AC adjustable motor drives.

	AN INVESTIGATION OF CONTROL OF SWITCHED RELUCTANCE MOTOR SUPPLIED BY A.C. PULSES By M. Oljaca; J. Corda	[View] [Download]
Abstract: This paper investigates the idea of supplying the switched reluctance motor with bipolar currents, obtained directly from an a.c. source (mains) which would eliminate the need for an input rectifier and a d.c. link capacitor in the electronic converter of the drive. The idea is based on the fact that the direction of the electromagnetic torque produced by a switched reluctance motor, is not dependant on the direction of the currents flowing through the motor windings. The power electronic circuit studied is suitable for use with a bifilar wound motor. It requires two switching elements and two diodes per phase. The control by position-dependant switching in the single pulse operating mode and the control by current limit In the chopping mode are investigated. It is shown that apart from having a undesirable harmonic content in the supply current the drive could be successfully controlled at lower speeds.