EPE Association: EPE 1991 - 30 - Session 3.8: PERMANENT MAGNET MOTOR DRIVES

EPE 1991 - 30 - Session 3.8: PERMANENT MAGNET MOTOR DRIVES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 30 - Session 3.8: PERMANENT MAGNET MOTOR DRIVES

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   INFLUENCE OF THE DYNAMICS OF THE MECHANICAL SPEED OF A SYNCHRONOUS SERVOMOTOR ON ITS TORQUE REGULATION, PROPOSAL OF A ROBUST SOLUTION
By B. Le Pioufle; J. P. Louis [View]
[Download]

Abstract: In this paper is presented a precise analytic study of the influence of the mechanical acceleration on a classical PI torque controller in the DQ frame. We treate the case of a sinusoïdal space distribution synchronous servomotor fed by a PWM inverter. We show that acceleration creates lacks of torque, which make the speed regulation loop become slower. We shall show that including the compensation of the effects of Q in the PI torque controller permits us to avoid these lacks of torque. The robustness of the latter solution is tested. The above theorical study is validated by simulation and experimental results.

   AN IMPROVED POSITION ESTIMATOR FOR SENSORLESS CONTROLLED PERMANENT MAGNET SYNCHRONOUS MOTORS
By M. Schrödl [View]
[Download]

Abstract: The paper deals with the detection of the rotor angular position of permanent magnet synchronous motors without using position encoders. Two different models are used - the INFORM model for low angular velocities and an e.m.f. based algorithm for higher velocities. Based on the detected mechanical quantities a Kalman filter is constructed which estimates angular velocity, position and load torque of the machine. The algorithms are implemented on a digital signal processing system. Measurements verify the properties of the "sensorless" drive.

   OPTIMIZATION OF VOLTAGE SHAPE FOR OPERATION OF A SYNCHRONOUS MAGNETO MACHINE IN THE FIELD WEAKENING RANGE
By R. Fehringer; K. Kaiser [View]
[Download]

Abstract: Electrical machines with permanent-magnet excitation are increasingly gaining in importance because of the growing use of high-energy permanent magnets. Their advantages are found particularly in the possibility of more compact and lighter designs and of dispensing with exciter power. On the other hand, the rigid excitation is a drawback in cases where constant-power operation is required over a wide speed range (weakening of field). Conventional rotary-field machines with permanent-magnet excitation are only conditionally suitable for field-weakening operation, as the current load of the converter is not sufficiently reduced in the process. However, a rearrangement of the magnetic structure of the machine on the transverse-flux principle offers more favorable conditions for field weakening. The following article attempts to show how large speed ranges may be covered at minimum current requirements by optimizing the characteristic of the terminal voltage of the transverse-flux machine (TFM for short). Optimization occurs analytically by application of the maximum principle according to Pontryagin.

   FIELD WEAKENING OF BRUSHLESS PERMANENT MAGNET SERVOMOTORS WITH RECTANGULAR CURRENT
By G. Schaefer [View]
[Download]

Abstract: For extension of speed and torque range of permanent excited brushless servomotors the principle of weakening the permanent field with a negativ d-axis current is used. The current control of sinusoidal-fed PM motors includes the control of the d-axis stator current and therefore it is simple to produce a negative d-axis stator current to weaken the permanent field of the motor. The control of the sinusodial-fed PM motor is rather complex because it needs two current regulators and a high resolution rotor position encoder. Rectangular-fed PM motor drives need only one current regulator and a simple rotor position encoder. A simple additional circuit prepoposes the switching points of the phase current in high speed region. This precommutation circuit enables the current regulator of the rectangular-fed PM motor to produce a negative d-axis current to weaken the permanent field of the motor.

   HIGH-SPEED PC-BASED CAD FOR BRUSHLESS MOTOR DRIVES
By T. J. E. Miller; M. McGilp [View]
[Download]

Abstract: This paper describes two CAD programs (PC-SRD and PC-BDC) for the design of brushless DC and switched reluctance motors and their power-electronic controllers, suitable for use on personal computers or workstations. The programs are used for "sizing", for system design, and for simulation of brushless DC and SR drives. Specially developed algorithms minimize computation so that a large number of designs and parameter-changes can be evaluated in a short time, permitting the use of a shell programm that performs "ranging", with graphical output that enables the designer to select optimal parameters. The programs are unique in their use of state-space averaging to obviate the need for time-stepping integration of the differential voltage equations at low speed. In addition to the performance parameters for the motor and the complete system, the programs calculate peak, mean, and r.m.s. currents in all the transistors and diodes of the power electronic controller and over 100 other performance parameters. Also described are the software-engineering aspects. PC-SRD and PC-BDC deliver to their users an order-of-magnitude gain in engineering productivity compared with traditional design software techniques. This gain is achieved by the integration of all or most of the design tasks, and is made possible by the recent development of powerful PC-based development environments, compilers, and operating systems with high-level languages, object-oriented programming and advanced graphics and windowing.

   ANALYSYS OF A PERMANENT MAGNET MOTOR WITH A STAINLESS CAN IN THE AIR GAP
By Jun Oyama; Tsuyoshi Higuchi; Hidenori Kotono; Eiji Yamada [View]
[Download]

Abstract: A long-gap and short-diameter permanent magnet motor with a stainless can in the air gap is analyzed using the finite element method. The effect of the motor speed and temperature rise on the eddy current loss in the stainless can is investigated theoretically. The presented voltage input type analysis enables us to estimate the current wave form and the performance characteristics such as efficiency and power factor. The calculated results agree well with the experimental results.

   ANALISYS OF BRUSHLESS DC MOTOR PERFORMANCE WHEN FAULTS OCCURRENCE
By A.M. Oliveira; A. G. Badan Palhares; A. H. Kumakura; G. Winnischofer; A. Hoshino [View]
[Download]

Abstract: The increasing applications of permanent magnet electronic commutated motor (Brushless DC Motor) has motivated us to study the performance of this motor applied to naval propulsion and submitted to the following fault conditions:
- Short circuit at one phase
- Fault in current semicycle inversion at one phase
- Fault at one or more inverter module opening the corresponding phases.
The analysis is based on a prototype of 75 kW, constructed with similar characteristics of converter fed permanent field motor presented at Munich ICEM 86 by H. Fürsich and at Aachen EPE 89 by J. Saint Michel, and a simulation of a mathematical model developed using TUTSIM program for comparison between experimental and theoretical results. The aim is to quantify the advantage of the construction form with independent phases in order to avoid motor stopping in case of faults, relating with control methods to minimize the effects of these faults during motor operation in various load conditions and speeds, e.g., pulsating torques, reduction of power.

   MODELLING, NON-LINEAR SIMULATION AND DYNAMIC PERFORMANCE OF A CURRENT CONTROLLED PERMANENT-MAGNET SYNCHRONOUS MOTOR DRIVE
By M. J. Kamper; F. S. van der Merwe [View]
[Download]

Abstract: The measured speed and phase current responses of a permanent magnet synchronous motor (PMSM) drive for step input speed commands are given. The results show, at zero speed, that the phase currents build up within 1 ms to their maximum values after a step input speed command. Transfer function models of the PMSM and speed controller of the drive system have been obtained. Computer simulations of the response of the drive system are presented, with due allowance for all important nonlinearities, amongst others, the finite current and voltage capability of the inverter. The important effect of these non-linearities on the hysteresis and PWM current control performances of the drive is shown.

   MODELLING AND DIGITAL SIMULATION OF TWO CURRENT CONTROL METHODS FOR A PERMANENT MAGNET SYNCHRONOUS MOTOR SUPPLIED BY PWM-VSI
By T. Rekioua; M. Meibody-Tabar; F. M. Sargos; R. Le Doeuff [View]
[Download]

Abstract: The present paper deals with two current control methods for a pulse width modulation controlled voltage source inverter (PWM-VSI) supplying a permanent magnet synchronous motor (PMSM). The first current control algorithm in d-q axes allows to achieve an independent control of the direct and quadrature currents for salient or smooth motors. Moreover the current loops reduce from second to first order, so that the regulators become simpler to design. The second method is an extension of the first algorithm applied to the three-phase current controllers of non salient PMSMs. This algorithm allows to control independently the phase currents without using the rotor position in the current loops. This study takes into account the sampling of the variables and their numerical precisions. Finally, the simulated results of both methods are compared: they prove to be identical.

   THE ELECTRICAL AND THERMAL PERFORMANCES OF A TOROIDAL-STATOR PERMANENT MAGNET BRUSHLESS D.C. MACHINE
By M. M. El Missiry; E. Spooner [View]
[Download]

Abstract: The paper presents the electrical and thermal performance curves of a class of axial flux brushless d.c. machine suitable for engine starter/generator applications. The machine is compact, has a high efficiency and lends itself to be directly coupled to an engine shaft. It uses the new magnetic material Neodymium-Iron-Baron as a source of magnetization. The machine can be used as an engine starter if a brushless controller is employed.

   THE ANALYTICAL DETERMINATION OF THE CHARACTERISTICS OF PERMANENT MAGNET BRUSHLESS DC DRIVES
By R. Carlson; J. Cros; M. Lajoie-Mazenc [View]
[Download]

Abstract: An analytical formulation to calculate the average torque versus speed characteristics of brushless DC drives is presented. The form of this characteristics is shown to be a consequence of the torque perturbation caused by the phases commutation by the inverter. The analytical formulation is based on the analysis of the behavior of the system in three well identified regions of operation: one at low speeds where the phase emf is lower than four times the voltage at the inverter dc terminal, the second one occurs at an intermediate speed region where the phase emf is greater than four times the voltage at the dc inverter terminals and the third one has the same condition on the emf and dc voltage as the second region but the inverter current is not controlled any more. The analytical formulation considers both the current control by an hysteresis band and the current control by PWM. Simulation results are used to validate the proposed analytical model.

   PERMANENT MAGNET SYNCHRONOUS MOTOR DRIVE WITH SLIDING MODE CONTROL
By S. Rivkin [View]
[Download]

Abstract: This paper presents the sliding mode control for a typical ac ,drive with inverter fed permanent magnet synchronous motor. The introducting of sliding mode in the control system helps to achieve good dynamical response, disturbance rejection and low sensibility to plant parameter variations of the ac drive. The synthesis of sliding mode control system and the control laws for the controls of speed and current are described. The block-diagram of the considered drive is shown.

   HIGH PERFORMANCE SPINDLE DRIVES ADOPTING IPM SYNCHRONOUS MACHINES: THEORETICAL GOALS AND A PRACTICAL SOLUTION
By Antonino Fratta; Roberto Grassi; Alfredo Vagati [View]
[Download]

Abstract: A drive system is presented which allows the practical exploitation of the outstanding performances theoretically predicted for the high anisotropy IPM synchronous machines. For torque ratings from 10 to 300 Nm, with a large constant-power speed ratio, special IPM motors with high torque density are adopted. Their quadrature inductance is minimized to allow the use of low cost permanent magnets for its compensation. The linear anisotropy ratio reaches the value of around one tenth. Driving with fast torque response these motors, their complex and non-linear magnetic model is the main problem, especially when the supply voltage is not greatly redundant with respect to the motor emf. A simplified trade-off among different approaches is outlined. By considering the control algorithm as well as the hardware design, a control structure has been implemented, based on a real time (HW) field observation and state regulation together with a full digital (SW) parameter adaptation.

   DEVELOPMENT OF A IGBT INVERTER DRIVEN AXIAL-FLUX PM SYNCHRONOUS MOTOR DRIVE
By F. Caricchi; F. Crescimbini; A. Di Napoli; O. Honorati; T. A. Lipo; G. Noia; E. Santini [View]
[Download]

Abstract: Available high-field permanent magnets have opened opportunities for axial-flux PM machines, which can find their advantageous application in low-speed high-torque electrical drives. Applications of axial-flux PM motor drives prompt new solutions in designing both the machine and the power converter. In particular, this the paper discusses innovative design criteria which lead to a machine of high efficiency and reduced costs by maximizing the torque/weight ratio. Furthermore, a novel power converter topology is illustrated, considering machine supply requirements which allow an improvement in the drive performance. Finally, the paper presents the characteristics of a low-speed high-torque motor drive, which has been constructed using an IGBT power converter together with a 1.3 kW axial-flux machine having Ne-Fe-B permanent magnets and slotless stator winding wound in a toroidal fashion.

EPE 1991 - 30 - Session 3.8: PERMANENT MAGNET MOTOR DRIVES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 30 - Session 3.8: PERMANENT MAGNET MOTOR DRIVES
	[return to parent folder]

	INFLUENCE OF THE DYNAMICS OF THE MECHANICAL SPEED OF A SYNCHRONOUS SERVOMOTOR ON ITS TORQUE REGULATION, PROPOSAL OF A ROBUST SOLUTION By B. Le Pioufle; J. P. Louis	[View] [Download]
Abstract: In this paper is presented a precise analytic study of the influence of the mechanical acceleration on a classical PI torque controller in the DQ frame. We treate the case of a sinusoïdal space distribution synchronous servomotor fed by a PWM inverter. We show that acceleration creates lacks of torque, which make the speed regulation loop become slower. We shall show that including the compensation of the effects of Q in the PI torque controller permits us to avoid these lacks of torque. The robustness of the latter solution is tested. The above theorical study is validated by simulation and experimental results.

	AN IMPROVED POSITION ESTIMATOR FOR SENSORLESS CONTROLLED PERMANENT MAGNET SYNCHRONOUS MOTORS By M. Schrödl	[View] [Download]
Abstract: The paper deals with the detection of the rotor angular position of permanent magnet synchronous motors without using position encoders. Two different models are used - the INFORM model for low angular velocities and an e.m.f. based algorithm for higher velocities. Based on the detected mechanical quantities a Kalman filter is constructed which estimates angular velocity, position and load torque of the machine. The algorithms are implemented on a digital signal processing system. Measurements verify the properties of the "sensorless" drive.

	OPTIMIZATION OF VOLTAGE SHAPE FOR OPERATION OF A SYNCHRONOUS MAGNETO MACHINE IN THE FIELD WEAKENING RANGE By R. Fehringer; K. Kaiser	[View] [Download]
Abstract: Electrical machines with permanent-magnet excitation are increasingly gaining in importance because of the growing use of high-energy permanent magnets. Their advantages are found particularly in the possibility of more compact and lighter designs and of dispensing with exciter power. On the other hand, the rigid excitation is a drawback in cases where constant-power operation is required over a wide speed range (weakening of field). Conventional rotary-field machines with permanent-magnet excitation are only conditionally suitable for field-weakening operation, as the current load of the converter is not sufficiently reduced in the process. However, a rearrangement of the magnetic structure of the machine on the transverse-flux principle offers more favorable conditions for field weakening. The following article attempts to show how large speed ranges may be covered at minimum current requirements by optimizing the characteristic of the terminal voltage of the transverse-flux machine (TFM for short). Optimization occurs analytically by application of the maximum principle according to Pontryagin.

	FIELD WEAKENING OF BRUSHLESS PERMANENT MAGNET SERVOMOTORS WITH RECTANGULAR CURRENT By G. Schaefer	[View] [Download]
Abstract: For extension of speed and torque range of permanent excited brushless servomotors the principle of weakening the permanent field with a negativ d-axis current is used. The current control of sinusoidal-fed PM motors includes the control of the d-axis stator current and therefore it is simple to produce a negative d-axis stator current to weaken the permanent field of the motor. The control of the sinusodial-fed PM motor is rather complex because it needs two current regulators and a high resolution rotor position encoder. Rectangular-fed PM motor drives need only one current regulator and a simple rotor position encoder. A simple additional circuit prepoposes the switching points of the phase current in high speed region. This precommutation circuit enables the current regulator of the rectangular-fed PM motor to produce a negative d-axis current to weaken the permanent field of the motor.

	HIGH-SPEED PC-BASED CAD FOR BRUSHLESS MOTOR DRIVES By T. J. E. Miller; M. McGilp	[View] [Download]
Abstract: This paper describes two CAD programs (PC-SRD and PC-BDC) for the design of brushless DC and switched reluctance motors and their power-electronic controllers, suitable for use on personal computers or workstations. The programs are used for "sizing", for system design, and for simulation of brushless DC and SR drives. Specially developed algorithms minimize computation so that a large number of designs and parameter-changes can be evaluated in a short time, permitting the use of a shell programm that performs "ranging", with graphical output that enables the designer to select optimal parameters. The programs are unique in their use of state-space averaging to obviate the need for time-stepping integration of the differential voltage equations at low speed. In addition to the performance parameters for the motor and the complete system, the programs calculate peak, mean, and r.m.s. currents in all the transistors and diodes of the power electronic controller and over 100 other performance parameters. Also described are the software-engineering aspects. PC-SRD and PC-BDC deliver to their users an order-of-magnitude gain in engineering productivity compared with traditional design software techniques. This gain is achieved by the integration of all or most of the design tasks, and is made possible by the recent development of powerful PC-based development environments, compilers, and operating systems with high-level languages, object-oriented programming and advanced graphics and windowing.

	ANALYSYS OF A PERMANENT MAGNET MOTOR WITH A STAINLESS CAN IN THE AIR GAP By Jun Oyama; Tsuyoshi Higuchi; Hidenori Kotono; Eiji Yamada	[View] [Download]
Abstract: A long-gap and short-diameter permanent magnet motor with a stainless can in the air gap is analyzed using the finite element method. The effect of the motor speed and temperature rise on the eddy current loss in the stainless can is investigated theoretically. The presented voltage input type analysis enables us to estimate the current wave form and the performance characteristics such as efficiency and power factor. The calculated results agree well with the experimental results.

	ANALISYS OF BRUSHLESS DC MOTOR PERFORMANCE WHEN FAULTS OCCURRENCE By A.M. Oliveira; A. G. Badan Palhares; A. H. Kumakura; G. Winnischofer; A. Hoshino	[View] [Download]
Abstract: The increasing applications of permanent magnet electronic commutated motor (Brushless DC Motor) has motivated us to study the performance of this motor applied to naval propulsion and submitted to the following fault conditions: - Short circuit at one phase - Fault in current semicycle inversion at one phase - Fault at one or more inverter module opening the corresponding phases. The analysis is based on a prototype of 75 kW, constructed with similar characteristics of converter fed permanent field motor presented at Munich ICEM 86 by H. Fürsich and at Aachen EPE 89 by J. Saint Michel, and a simulation of a mathematical model developed using TUTSIM program for comparison between experimental and theoretical results. The aim is to quantify the advantage of the construction form with independent phases in order to avoid motor stopping in case of faults, relating with control methods to minimize the effects of these faults during motor operation in various load conditions and speeds, e.g., pulsating torques, reduction of power.

	MODELLING, NON-LINEAR SIMULATION AND DYNAMIC PERFORMANCE OF A CURRENT CONTROLLED PERMANENT-MAGNET SYNCHRONOUS MOTOR DRIVE By M. J. Kamper; F. S. van der Merwe	[View] [Download]
Abstract: The measured speed and phase current responses of a permanent magnet synchronous motor (PMSM) drive for step input speed commands are given. The results show, at zero speed, that the phase currents build up within 1 ms to their maximum values after a step input speed command. Transfer function models of the PMSM and speed controller of the drive system have been obtained. Computer simulations of the response of the drive system are presented, with due allowance for all important nonlinearities, amongst others, the finite current and voltage capability of the inverter. The important effect of these non-linearities on the hysteresis and PWM current control performances of the drive is shown.

	MODELLING AND DIGITAL SIMULATION OF TWO CURRENT CONTROL METHODS FOR A PERMANENT MAGNET SYNCHRONOUS MOTOR SUPPLIED BY PWM-VSI By T. Rekioua; M. Meibody-Tabar; F. M. Sargos; R. Le Doeuff	[View] [Download]
Abstract: The present paper deals with two current control methods for a pulse width modulation controlled voltage source inverter (PWM-VSI) supplying a permanent magnet synchronous motor (PMSM). The first current control algorithm in d-q axes allows to achieve an independent control of the direct and quadrature currents for salient or smooth motors. Moreover the current loops reduce from second to first order, so that the regulators become simpler to design. The second method is an extension of the first algorithm applied to the three-phase current controllers of non salient PMSMs. This algorithm allows to control independently the phase currents without using the rotor position in the current loops. This study takes into account the sampling of the variables and their numerical precisions. Finally, the simulated results of both methods are compared: they prove to be identical.

	THE ELECTRICAL AND THERMAL PERFORMANCES OF A TOROIDAL-STATOR PERMANENT MAGNET BRUSHLESS D.C. MACHINE By M. M. El Missiry; E. Spooner	[View] [Download]
Abstract: The paper presents the electrical and thermal performance curves of a class of axial flux brushless d.c. machine suitable for engine starter/generator applications. The machine is compact, has a high efficiency and lends itself to be directly coupled to an engine shaft. It uses the new magnetic material Neodymium-Iron-Baron as a source of magnetization. The machine can be used as an engine starter if a brushless controller is employed.

	THE ANALYTICAL DETERMINATION OF THE CHARACTERISTICS OF PERMANENT MAGNET BRUSHLESS DC DRIVES By R. Carlson; J. Cros; M. Lajoie-Mazenc	[View] [Download]
Abstract: An analytical formulation to calculate the average torque versus speed characteristics of brushless DC drives is presented. The form of this characteristics is shown to be a consequence of the torque perturbation caused by the phases commutation by the inverter. The analytical formulation is based on the analysis of the behavior of the system in three well identified regions of operation: one at low speeds where the phase emf is lower than four times the voltage at the inverter dc terminal, the second one occurs at an intermediate speed region where the phase emf is greater than four times the voltage at the dc inverter terminals and the third one has the same condition on the emf and dc voltage as the second region but the inverter current is not controlled any more. The analytical formulation considers both the current control by an hysteresis band and the current control by PWM. Simulation results are used to validate the proposed analytical model.

	PERMANENT MAGNET SYNCHRONOUS MOTOR DRIVE WITH SLIDING MODE CONTROL By S. Rivkin	[View] [Download]
Abstract: This paper presents the sliding mode control for a typical ac ,drive with inverter fed permanent magnet synchronous motor. The introducting of sliding mode in the control system helps to achieve good dynamical response, disturbance rejection and low sensibility to plant parameter variations of the ac drive. The synthesis of sliding mode control system and the control laws for the controls of speed and current are described. The block-diagram of the considered drive is shown.

	HIGH PERFORMANCE SPINDLE DRIVES ADOPTING IPM SYNCHRONOUS MACHINES: THEORETICAL GOALS AND A PRACTICAL SOLUTION By Antonino Fratta; Roberto Grassi; Alfredo Vagati	[View] [Download]
Abstract: A drive system is presented which allows the practical exploitation of the outstanding performances theoretically predicted for the high anisotropy IPM synchronous machines. For torque ratings from 10 to 300 Nm, with a large constant-power speed ratio, special IPM motors with high torque density are adopted. Their quadrature inductance is minimized to allow the use of low cost permanent magnets for its compensation. The linear anisotropy ratio reaches the value of around one tenth. Driving with fast torque response these motors, their complex and non-linear magnetic model is the main problem, especially when the supply voltage is not greatly redundant with respect to the motor emf. A simplified trade-off among different approaches is outlined. By considering the control algorithm as well as the hardware design, a control structure has been implemented, based on a real time (HW) field observation and state regulation together with a full digital (SW) parameter adaptation.

	DEVELOPMENT OF A IGBT INVERTER DRIVEN AXIAL-FLUX PM SYNCHRONOUS MOTOR DRIVE By F. Caricchi; F. Crescimbini; A. Di Napoli; O. Honorati; T. A. Lipo; G. Noia; E. Santini	[View] [Download]
Abstract: Available high-field permanent magnets have opened opportunities for axial-flux PM machines, which can find their advantageous application in low-speed high-torque electrical drives. Applications of axial-flux PM motor drives prompt new solutions in designing both the machine and the power converter. In particular, this the paper discusses innovative design criteria which lead to a machine of high efficiency and reduced costs by maximizing the torque/weight ratio. Furthermore, a novel power converter topology is illustrated, considering machine supply requirements which allow an improvement in the drive performance. Finally, the paper presents the characteristics of a low-speed high-torque motor drive, which has been constructed using an IGBT power converter together with a 1.3 kW axial-flux machine having Ne-Fe-B permanent magnets and slotless stator winding wound in a toroidal fashion.