EPE Association: EPE 1999 - Topic 05a: Permanent Magnet Motor Drives

EPE 1999 - Topic 05a: Permanent Magnet Motor 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 05a: Permanent Magnet Motor Drives

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   Accurate Modelling and Simulation of a High Performance Permanent...
By R. A. Guinee; C. Lyden, [View]
[Download]

Abstract: A very accurate mathematical model of a high performance three phase permanent magnet motor adjustable speed drive (ASD) system, including interaction with the servoamplifier power conditioner, based on physical principles is presented. The resultant discrete time model is used to simulate the dynamics and pulsewidth modulation (PWM) inverter control, with converter blanking, of the brushless motor drive (BLMD) for parameter identification in adaptive control. This model can also be used as a valuable simulation tool in performance related prediction studies for proposed embedded drive systems. Numerical waveform simulation at critical model observation nodes gave excellent agreement in terms of correlation with BLMD experimental test data for model fidelity purposes. Simulated trace coherence with typical drive test data, relying on stator winding current feedback possessing frequency modulation attributes, validates and attests to the accuracy of the model which is an essential feature of the system identification process. Cost surface simulation, as means of motor parameter identification based on the mean squared error (MSE) between the experimental and simulated observed variables, provides insight into the location of the global minimizer and thus an estimate of the optimal dynamical parameters. The returned parameter estimates are almost identical to those for known inertial shaft loads which provides further BLMD model confidence.

   Carrier Frequency Method of IPM Motor Rotor Position Determination
By M. Mamo; J. Oyama; T. Abe; T. Higuchi; E. Yamada [View]
[Download]

Abstract: Carrier Frequency Component Voltage (CFCV), in a PWM inverter supplying an Interior Permanent Magnet (IPM) motor, is used as the rotor position information source. Mathematical expressions relating the CFCV and the Carrier Frequency Component Current (CFCC) with the rotor position, developed previously in [1] and [2], are simplified and implemented to control the IPM motor. The motor speed has been successfully controlled without mechanical sensor in the lower speed range (0 to 50% rated speed). Experimental results are presented and discussed.

   Design of Axial-Flux PM Machine for HEV
By F. Sahin; A.J.A. Vandenput [View]
[Download]

Abstract: This paper discusses the design decisions made for an 18000 rpm, 34 kW electrical machine that will be mounted into the flywheel-unit of a hybrid electrical vehicle. The maximum outside diameter of the electrical machine is limited due to the flywheel arrangement. The machine must be compact and very high efficiency levels are desirable. An axial-flux-permanent-magnet (AFPM) machine is found to be the most suitable type as far as its shape is concerned. The sinusoidal-current driven machine is preferred for its efficiency. The effect of outside diameter, inside-to-outside diameter ratio, number of slots, magnet span, skewing, and stator offsetting are discussed for AFPM machine in relation to the given application requirements.

   Field-weakening control of an interior permanent magnet motor for application in electric vehicles
By S. Bosga; H. Zelaya de la Para [View]
[Download]

Abstract: Interior Permanent Magnet (IPM) Motors have become a popular choice in electric vehicle applications, due to their excellent power to weight ratio. The paper describes the implementation of the field-weakening strategy that allows a 4:1 speed ration in a 50 kW (peak power) motor, with a base speed of 2500 rpm. The attractive features of the controller are highlighted in both low and high speeds of operation, where losses are minimised and peak power is made available up to 10.000 rpm. At low speeds, the reluctance torque is used to maximise the output for a given current level; this is achieved in the practical implementation selecting an optimal value of the direct stator current component. On the other hand, at higher speeds the system reaches a point at which the converter will not be able to supply the desired voltage. In this case it is necessary to make use of an increased value of the direct current component. The results presented here are for both simulation and practical implementation using a voltage source inverter supplied from a traction battery with a nominal 300 V. A discussion on further improvements and dynamic characteristics of the system is finally presented to conclude the paper. Hardware and software development have been carried out under the Project Supervision of ABB Hybrid Systems based in Vasteras, Sweden.

   New Integral Motor Stator Design with Integrated Filter Coils
By P. Thelin [View]
[Download]

Abstract: Integral motors are normally higher or longer than standard motors, due to the space required for the converter. To make the integral motor more compact, the coils of line-filter and the coil of the DC-link have been integrated with the stator core. Measurements on the manufactured prototype machine show that the integration does not deteriorate the motor performance. The measurements also show that the high-frequency content of the line current to the integral motor (i.e. the converter input current) is reduced. The new design has several advantages compared to conventional designs.

   Overload and Flux-Weakening Performance of an IPM Motor Drive
By N. Bianchi; S. Bolognani; F. Parasiliti; M. Villani [View]
[Download]

Abstract: The performance of an interior permanent magnet synchronous motor are predicted at base speed and in the flux-weakening speed range, given the geometrical and physical data of the motor. Iron saturation of the magnetic circuit is taken into account. Both the continuous (rated) and the intermittent (overload) operating regions are considered. Two different approaches to the analysis are proposed: (i) by means of an analytical model in which the non-linearity due to the iron saturation is described in a simplified way, on the basis of the results of few finite element analyses; (ii) by means of a complete finite element analysis carried out in all the operating point of interest. Accuracy of the methods is verified by comparing their results with experimental measurements. Merits, drawbacks and limits of the two methods are also discussed.

   PMSM Drive with Bi-directional Power Transfer Capability
By R. Matos; N. Esteves; J. Esteves; P. Verdelho [View]
[Download]

Abstract: This paper presents modelling, simulation and experimental verification of a permanent magnet synchronous motor drive (PMSM) with bi-directional power transfer capability. A permanent magnet synchronous machine connected to a dc voltage link by a PWM voltage type converter composes the system. A second PWM voltage type converter connects this dc link to the ac network. The control objectives of the PWM voltage converter connected to the ac mains are to ensure a unity power factor, and to maintain the DC voltage in a constant value. The unity power factor is achieved by setting the phase current references with the same waveform as the mains phase voltages, and a proportional-integral controller, acting in the magnitude of the current references, controls the DC voltage. In the PWM voltage converter connected to the PMSM, the quadrature Park's current component is controlled, and a null value for the direct current component is imposed. By this way, the machine electromagnetic torque control is achieved, and decoupling between flux and torque is obtained. From the AC mains viewpoint, near sinusoidal input current waveforms are obtained. Also load power variations do not produce reactive power variations in the converter AC side.

   Remedial Strategy for a Permanent Magnet Synchronous Motor Drive
By A. Krautstrunk; P. Mutschler [View]
[Download]

Abstract: Aerospace as well as automotive applications demand auxiliary drives with a high power density and a high reliability. Permanent magnet synchronous motor drives (PMSM) offer a high power density. Reliability can be improved by special motor designs [2], [5] or by means of remedial operation strategies [6], [1]. This paper describes a remedial approach with a standard three phase machine. If one phase is faulted, the remaining phases won’t be affected and will achieve in most cases the same performance as the unfaulted drive. This will be reached by separating the three phases electrically. Some applications demand high torque at low speed with little or no torque ripple. Special attention will be paid to the torque ripple, if a part of the drive is faulted.

   Saturation Effects on IPM Motor Performance and Design
By N. Bianchi; S. Bolognani [View]
[Download]

Abstract: This paper illustrates a procedure to individuate the parameters and the volt-ampere ratings of an interior permanent magnet synchronous motor drive to meet a prefixed torque-speed operating characteristic, taking into account the iron saturation (saturated motor). This is achieved by an appropriate model of the magnetic flux-current curves of the motor. A well-suited normalisation with base speed and related torque as base quantities is proposed to generalise the results as much as possible. Particular attention is devoted to the comparison between motor parameters and capabilities of unsaturated and saturated motor drives in the whole speed range including the flux-weakening region. Then the paper indicates some guidelines for the design of the motor in order to satisfy the required torque-speed specifications. It is shown that an accurately designed saturated motor may exhibit the required performance with smaller dimensions than an unsaturated one.

   Simulation and Experimental Investigation of Dynamic Field-Weakening Performance of Permanent Magnet Brushless AC Drives
By Y.S. Chen; Z.Q. Zhu; D. Howe [View]
[Download]

Abstract: An improved simulation model has been developed for predicting the dynamic performance of vectorcontrolled permanent magnet brushless ac drive systems on the Simulink/Matlab environment, with particular reference to their field-weakening performance. It caters for the characteristics of brushless permanent magnet synchronous motor and alternative field-weakening control and PWM strategies, etc. In addition, it accounts for the effect of magnetic saturation, e.g. the dependence of winding inductances on the currents, and is capable of real-time compensation of the effect of winding resistance etc. The predictions are validated by experiments made on a DSP controlled drive system. The simulation model is then used to investigate the transient and steady-state dynamic performances of an interior magnet brushless ac motor in both constant torque and constant power operation ranges.

   Synchronous Multi-Motor Drive with Field Oriented Position Control for Windpower Pitch Drive Application
By A. Dittrich; E. Julen [View]
[Download]

Abstract: In windpower pitch drives up to three motors have to be controlled with very accurate speed and angular synchronism under varying load conditions. In the paper a very cost-effective solution is proposed with three PM motors connected to one frequency converter. A new field-oriented like control principle is outlined, ensuring the desired synchronism and avoiding motor pull-out in all operating modes and at unsymmetrical load.

   The Control of Interior Permanent Magnet Synchronous Motor Using a Non-Linear Minimum Order Observer
By V. Comnac; M. McCormick; A. Aounis; M. Cernat; R-M. Cernat [View]
[Download]

Abstract: The application of vector control techniques in a.c. drives demands accurate position and speed feedback information for the current control and servo-control loops. The paper describes a full mechanical sensorless speed digital control system for interior permanent magnet synchronous machines (IPMSM). A minimum order state observer (Gopinath) is used for the mechanical state estimation of the motor. The observer was developed based on non-linear model of the synchronous motor, that employs a d-q rotating reference frame attached to the rotor. As opposed to the complete order state observer (Luenberger) which is often cited in literature, the minimum order state observer (Gopinath) is easier to design in the stage of pole placement. The control system includes a rotor frame vector current controller with feedforward decoupling circuit and an integral+integral proportional (I + PI) speed controller.

   Torque and Speed Control of Inverter-Fed Interior Permanent Magnet Synchronous Motor Using Sliding Mode
By V. Comnac; M. Cirstea; M. Giamusi; R-M. Cernat [View]
[Download]

Abstract: The paper presents a digital control system of speed for an interior permanent magnet synchronous motor (IPMSM), based on the sliding mode control of the electromagnetic torque. The design of the control system relies on the invariance of the reactive and electromagnetic torques property in relation to the change of the reference frame of the space vectors. The torque controller was designed taking into consideration a model of the machine in the rotating reference frame attached to the stator flux space phasor. The feedback signals are determined by using the measured values of currents and voltages in the fixed two-phase system ( 7KHUHIHUHQFHIRUWKHUHDFWLYHWRUTXHLVdeduced by using the orthogonal system attached to the rotor (d-q). The reactive and electromagnetic torques are controlled by non-linear hysteresis controllers; their output signals are used for generating the control signals of the inverter, based on switching tables. The angular velocity controller is linear, of I+PI type. The real time simulations of the control system in C++ confirm the proposed solution.

EPE 1999 - Topic 05a: Permanent Magnet Motor 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 05a: Permanent Magnet Motor Drives
	[return to parent folder]

	Accurate Modelling and Simulation of a High Performance Permanent... By R. A. Guinee; C. Lyden,	[View] [Download]
Abstract: A very accurate mathematical model of a high performance three phase permanent magnet motor adjustable speed drive (ASD) system, including interaction with the servoamplifier power conditioner, based on physical principles is presented. The resultant discrete time model is used to simulate the dynamics and pulsewidth modulation (PWM) inverter control, with converter blanking, of the brushless motor drive (BLMD) for parameter identification in adaptive control. This model can also be used as a valuable simulation tool in performance related prediction studies for proposed embedded drive systems. Numerical waveform simulation at critical model observation nodes gave excellent agreement in terms of correlation with BLMD experimental test data for model fidelity purposes. Simulated trace coherence with typical drive test data, relying on stator winding current feedback possessing frequency modulation attributes, validates and attests to the accuracy of the model which is an essential feature of the system identification process. Cost surface simulation, as means of motor parameter identification based on the mean squared error (MSE) between the experimental and simulated observed variables, provides insight into the location of the global minimizer and thus an estimate of the optimal dynamical parameters. The returned parameter estimates are almost identical to those for known inertial shaft loads which provides further BLMD model confidence.

	Carrier Frequency Method of IPM Motor Rotor Position Determination By M. Mamo; J. Oyama; T. Abe; T. Higuchi; E. Yamada	[View] [Download]
Abstract: Carrier Frequency Component Voltage (CFCV), in a PWM inverter supplying an Interior Permanent Magnet (IPM) motor, is used as the rotor position information source. Mathematical expressions relating the CFCV and the Carrier Frequency Component Current (CFCC) with the rotor position, developed previously in [1] and [2], are simplified and implemented to control the IPM motor. The motor speed has been successfully controlled without mechanical sensor in the lower speed range (0 to 50% rated speed). Experimental results are presented and discussed.

	Design of Axial-Flux PM Machine for HEV By F. Sahin; A.J.A. Vandenput	[View] [Download]
Abstract: This paper discusses the design decisions made for an 18000 rpm, 34 kW electrical machine that will be mounted into the flywheel-unit of a hybrid electrical vehicle. The maximum outside diameter of the electrical machine is limited due to the flywheel arrangement. The machine must be compact and very high efficiency levels are desirable. An axial-flux-permanent-magnet (AFPM) machine is found to be the most suitable type as far as its shape is concerned. The sinusoidal-current driven machine is preferred for its efficiency. The effect of outside diameter, inside-to-outside diameter ratio, number of slots, magnet span, skewing, and stator offsetting are discussed for AFPM machine in relation to the given application requirements.

	Field-weakening control of an interior permanent magnet motor for application in electric vehicles By S. Bosga; H. Zelaya de la Para	[View] [Download]
Abstract: Interior Permanent Magnet (IPM) Motors have become a popular choice in electric vehicle applications, due to their excellent power to weight ratio. The paper describes the implementation of the field-weakening strategy that allows a 4:1 speed ration in a 50 kW (peak power) motor, with a base speed of 2500 rpm. The attractive features of the controller are highlighted in both low and high speeds of operation, where losses are minimised and peak power is made available up to 10.000 rpm. At low speeds, the reluctance torque is used to maximise the output for a given current level; this is achieved in the practical implementation selecting an optimal value of the direct stator current component. On the other hand, at higher speeds the system reaches a point at which the converter will not be able to supply the desired voltage. In this case it is necessary to make use of an increased value of the direct current component. The results presented here are for both simulation and practical implementation using a voltage source inverter supplied from a traction battery with a nominal 300 V. A discussion on further improvements and dynamic characteristics of the system is finally presented to conclude the paper. Hardware and software development have been carried out under the Project Supervision of ABB Hybrid Systems based in Vasteras, Sweden.

	New Integral Motor Stator Design with Integrated Filter Coils By P. Thelin	[View] [Download]
Abstract: Integral motors are normally higher or longer than standard motors, due to the space required for the converter. To make the integral motor more compact, the coils of line-filter and the coil of the DC-link have been integrated with the stator core. Measurements on the manufactured prototype machine show that the integration does not deteriorate the motor performance. The measurements also show that the high-frequency content of the line current to the integral motor (i.e. the converter input current) is reduced. The new design has several advantages compared to conventional designs.

	Overload and Flux-Weakening Performance of an IPM Motor Drive By N. Bianchi; S. Bolognani; F. Parasiliti; M. Villani	[View] [Download]
Abstract: The performance of an interior permanent magnet synchronous motor are predicted at base speed and in the flux-weakening speed range, given the geometrical and physical data of the motor. Iron saturation of the magnetic circuit is taken into account. Both the continuous (rated) and the intermittent (overload) operating regions are considered. Two different approaches to the analysis are proposed: (i) by means of an analytical model in which the non-linearity due to the iron saturation is described in a simplified way, on the basis of the results of few finite element analyses; (ii) by means of a complete finite element analysis carried out in all the operating point of interest. Accuracy of the methods is verified by comparing their results with experimental measurements. Merits, drawbacks and limits of the two methods are also discussed.

	PMSM Drive with Bi-directional Power Transfer Capability By R. Matos; N. Esteves; J. Esteves; P. Verdelho	[View] [Download]
Abstract: This paper presents modelling, simulation and experimental verification of a permanent magnet synchronous motor drive (PMSM) with bi-directional power transfer capability. A permanent magnet synchronous machine connected to a dc voltage link by a PWM voltage type converter composes the system. A second PWM voltage type converter connects this dc link to the ac network. The control objectives of the PWM voltage converter connected to the ac mains are to ensure a unity power factor, and to maintain the DC voltage in a constant value. The unity power factor is achieved by setting the phase current references with the same waveform as the mains phase voltages, and a proportional-integral controller, acting in the magnitude of the current references, controls the DC voltage. In the PWM voltage converter connected to the PMSM, the quadrature Park's current component is controlled, and a null value for the direct current component is imposed. By this way, the machine electromagnetic torque control is achieved, and decoupling between flux and torque is obtained. From the AC mains viewpoint, near sinusoidal input current waveforms are obtained. Also load power variations do not produce reactive power variations in the converter AC side.

	Remedial Strategy for a Permanent Magnet Synchronous Motor Drive By A. Krautstrunk; P. Mutschler	[View] [Download]
Abstract: Aerospace as well as automotive applications demand auxiliary drives with a high power density and a high reliability. Permanent magnet synchronous motor drives (PMSM) offer a high power density. Reliability can be improved by special motor designs [2], [5] or by means of remedial operation strategies [6], [1]. This paper describes a remedial approach with a standard three phase machine. If one phase is faulted, the remaining phases won’t be affected and will achieve in most cases the same performance as the unfaulted drive. This will be reached by separating the three phases electrically. Some applications demand high torque at low speed with little or no torque ripple. Special attention will be paid to the torque ripple, if a part of the drive is faulted.

	Saturation Effects on IPM Motor Performance and Design By N. Bianchi; S. Bolognani	[View] [Download]
Abstract: This paper illustrates a procedure to individuate the parameters and the volt-ampere ratings of an interior permanent magnet synchronous motor drive to meet a prefixed torque-speed operating characteristic, taking into account the iron saturation (saturated motor). This is achieved by an appropriate model of the magnetic flux-current curves of the motor. A well-suited normalisation with base speed and related torque as base quantities is proposed to generalise the results as much as possible. Particular attention is devoted to the comparison between motor parameters and capabilities of unsaturated and saturated motor drives in the whole speed range including the flux-weakening region. Then the paper indicates some guidelines for the design of the motor in order to satisfy the required torque-speed specifications. It is shown that an accurately designed saturated motor may exhibit the required performance with smaller dimensions than an unsaturated one.

	Simulation and Experimental Investigation of Dynamic Field-Weakening Performance of Permanent Magnet Brushless AC Drives By Y.S. Chen; Z.Q. Zhu; D. Howe	[View] [Download]
Abstract: An improved simulation model has been developed for predicting the dynamic performance of vectorcontrolled permanent magnet brushless ac drive systems on the Simulink/Matlab environment, with particular reference to their field-weakening performance. It caters for the characteristics of brushless permanent magnet synchronous motor and alternative field-weakening control and PWM strategies, etc. In addition, it accounts for the effect of magnetic saturation, e.g. the dependence of winding inductances on the currents, and is capable of real-time compensation of the effect of winding resistance etc. The predictions are validated by experiments made on a DSP controlled drive system. The simulation model is then used to investigate the transient and steady-state dynamic performances of an interior magnet brushless ac motor in both constant torque and constant power operation ranges.

	Synchronous Multi-Motor Drive with Field Oriented Position Control for Windpower Pitch Drive Application By A. Dittrich; E. Julen	[View] [Download]
Abstract: In windpower pitch drives up to three motors have to be controlled with very accurate speed and angular synchronism under varying load conditions. In the paper a very cost-effective solution is proposed with three PM motors connected to one frequency converter. A new field-oriented like control principle is outlined, ensuring the desired synchronism and avoiding motor pull-out in all operating modes and at unsymmetrical load.

	The Control of Interior Permanent Magnet Synchronous Motor Using a Non-Linear Minimum Order Observer By V. Comnac; M. McCormick; A. Aounis; M. Cernat; R-M. Cernat	[View] [Download]
Abstract: The application of vector control techniques in a.c. drives demands accurate position and speed feedback information for the current control and servo-control loops. The paper describes a full mechanical sensorless speed digital control system for interior permanent magnet synchronous machines (IPMSM). A minimum order state observer (Gopinath) is used for the mechanical state estimation of the motor. The observer was developed based on non-linear model of the synchronous motor, that employs a d-q rotating reference frame attached to the rotor. As opposed to the complete order state observer (Luenberger) which is often cited in literature, the minimum order state observer (Gopinath) is easier to design in the stage of pole placement. The control system includes a rotor frame vector current controller with feedforward decoupling circuit and an integral+integral proportional (I + PI) speed controller.

	Torque and Speed Control of Inverter-Fed Interior Permanent Magnet Synchronous Motor Using Sliding Mode By V. Comnac; M. Cirstea; M. Giamusi; R-M. Cernat	[View] [Download]
Abstract: The paper presents a digital control system of speed for an interior permanent magnet synchronous motor (IPMSM), based on the sliding mode control of the electromagnetic torque. The design of the control system relies on the invariance of the reactive and electromagnetic torques property in relation to the change of the reference frame of the space vectors. The torque controller was designed taking into consideration a model of the machine in the rotating reference frame attached to the stator flux space phasor. The feedback signals are determined by using the measured values of currents and voltages in the fixed two-phase system ( 7KHUHIHUHQFHIRUWKHUHDFWLYHWRUTXHLVdeduced by using the orthogonal system attached to the rotor (d-q). The reactive and electromagnetic torques are controlled by non-linear hysteresis controllers; their output signals are used for generating the control signals of the inverter, based on switching tables. The angular velocity controller is linear, of I+PI type. The real time simulations of the control system in C++ confirm the proposed solution.