EPE Association: EPE 2001 - Topic 06a: Permanent Magnet Machines and Drives

EPE 2001 - Topic 06a: Permanent Magnet Machines and Drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 06: ELECTRICAL MACHINES AND ADJUSTABLE SPEED DRIVES > EPE 2001 - Topic 06a: Permanent Magnet Machines and Drives

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   Design of a Compact BLDC Motor for Transient Applications
By Y.K. Chin; W.M. Arshad; T. Bäckström; C. Sadarangani [View]
[Download]

Abstract: such as emergency breakers, protective devices in explosive environments, emergency exit openings etc. fall into a broad category that can be grouped under a general term transient applications. This paper presents a compact brushless permanent magnet (BLDC) motor design for those short time operations. Design procedures for both interior and exterior rotor BLDC configurations are described. Design analysis is verified by testing and building a prototype motor. It is found that the most critical design criterion is to avoid magnet demagnetisation. A thermal check on the design is always advisable although thermal loading is negligible.

   Design of low speed PM motors for ac inverter drives
By T. Heikkilä; J. Pyrhönen; M. Niemelä [View]
[Download]

Abstract: Effective new control systems like Direct Torque Control (DTC) make it possible to introduce new high efficiency motors - such as permanent magnet synchronous motor (PMSM) - to this day’s demanding industry applications. Here a design of PMSM, which suits well to AC inverter drives are proposed.

   Design Steps towards a High Power Factor Transverse Flux Machine
By P. Anpalahan; J. Soulard; H-P. Nee [View]
[Download]

Abstract: This article describes a topology of three-phase transverse flux machine and the derivation of an analytical model which does not exist in the literature. Three dimensional finite element analysis is also used to get more accurate results. Steps carried out to obtain a better power factor are presented.

   Encoderless IPM Drive System For EV/HEV Propulsion Applications
By N. Patel; T. O’Meara; J. Nagashima; R. Lorenz [View]
[Download]

Abstract: This paper presents an accurate and robust method of estimating rotor position for an IPM (Interior Permanent Magnet) drive system for EV/HEV (Electric Vehicles/Hybrid Electric Vehicles) applications. The importance of encoderless technique for electric propulsion drives has been highlighted in the present study. Stability and dynamic behavior of the position estimation is critical in consumer-oriented traction applications. The paper provides experimental results, which demonstrate an excellent performance of the proposed control algorithm. The goal of this paper is to present an encoderless (or position sensorless) control method for EV/HEV propulsion drives which works over the entire torque-speed range including zero mechanical speed. The method combines two rotor position estimation techniques to fully cover both low (incl. zero) and high-speed ranges. Experimental results demonstrate excellent performance.

   High speed axial-flux permanent magnet machine
By F. Sahin; A. Tuckey; A.J.A Vandenput [View]
[Download]

Abstract: The paper gives an overview of the design, and particularly manufacturing and testing of a 16000 rpm, 30 kW axial-flux permanent-magnet (AFPM) synchronous machine. This machine is mounted inside and as an integral part of a flywheel that will subsequently be used in a hybrid electric vehicle. The paper describes the testing facility and includes the measurement results in comparison with the calculations.

   Hybrid PI and fuzzy logic speed control of PM brushless ac drives
By J. X. Shen; Z. Q. Zhu; D. Howe [View]
[Download]

Abstract: Speed controls with PI and fuzzy logic algorithms are implemented in a vector controlled PM brushless AC drive system. Parameters of the fuzzy logic controller are optimised while their influences are examined. Hybrid PI and fuzzy logic control is also proposed and implemented to achieve both excellent dynamic and steady state performances.

   IPM synchronous machine drive response to short circuit faults
By B. A. Welchko; T. M. Jahns; W. L. Soong; J. M. Nagashima [View]
[Download]

Abstract: A closed-form solution is presented for the steady-state response of interior permanent magnet (IPM) synchronous machines to symmetrical short circuits including the effects of q-axis magnetic saturation. Machine response to single-phase asymmetrical short circuits is also investigated. Experimental data is presented to verify predicted behavior for both types of short circuits. It is shown that single-phase asymmetrical short circuit faults produce more severe fault responses with high pulsating torque and a significant threat of rotor demagnetization. A control strategy that purposely transitions such faults into symmetrical three-phase short circuits can minimize the fault severity and associated demagnetization risks. Implications for the design of IPM machines with improved fault tolerance are discussed.

   Measured performances of a new hybrid synchronous machine.
By Y. Amara; E. Hoang; M. Gabsi; M. Lecrivain; A. H. Ben Ahmed; S. Dérou [View]
[Download]

Abstract: PM synchronous machines may operate over broad speed ranges at constant power thanks to the introduction of control laws that enable flux weakening. Generally, this control is accomplished by means of applying a strong demagnetizing current in the d-axis, yet such an approach engenders the risk of an irreversible demagnetization of the magnets and a reduction in machine performance. In this paper, we will present an original layout for the hybrid-excitation synchronous machine : an excitation by both magnets and coils. This solution allows for effective flux weakening without running the risk of demagnetizing the magnets.

   Modeling and Optimal Integration of a FPGA-Based Position Estimator fo
By Y.A. Chapuis; Y. Kebbati; T. Kosaka; N. Matsui [View]
[Download]

Abstract: This paper present a FPGA solution for a fuzzy logic based-position estimator of a sensorless controller of fully-pitched winding reluctance motor drives. A modular architecture of a position estimator is proposed in order to reach flexible and optimization performances of integration. Indeed, IC design can increase the specificity of a digital controller by exploiting the parallelism presented in most algorithms. Moreover, this solution can reduce the cost of the implementation by only use the necessary hardware. The aim of the integration is to relieve and to speed up the DSP calculation tasks while improving control results A modular architecture approach is proposed by decomposing the general algorithm of the position estimator in specific module architectures. Afterwards, these modules which are designed, synthesized and valid by simulation from VHDL models. Behavior simulation results of the FPGA are obtained by post-simulation and delay retro-annotation using Altera components library. Hardware results of position estimator integration will be also done.

   New dead-time compensation using disturbance observer
By H-S. Kim; H-T. Moon; M-J. Youn [View]
[Download]

Abstract: A new on-line dead-time compensation method for a permanent magnet (PM) synchronous motor drive is proposed. Using a simple disturbance observer without any additional circuits and off-line experimental measurements, disturbance voltages in the synchronous reference dq frame caused by the dead time and non-ideal switching characteristics of power devices are estimated in an on-line manner and fed to voltage references in order to compensate the dead-time effects. The proposed method is applied to a PM synchronous motor drive system and implemented by using software of a digital signal processor (DSP) TMS320C31. Experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed method.

   New Method for Efficiency Improvement of IPMSM
By L. Ma; M. Sanada; S. Morimoto; Y. Takeda; H. Murakami [View]
[Download]

Abstract: Recent progresses in power electronic device, rare-earth permanent magnet (PM) and modern motor control technology have made it possible for interior permanent magnet synchronous motor (IPMSM) to find wider application. In the applications which require operation ability above base speed, such as electric vehicles and compressors, except for large torque performance at low speed, high efficiency in extensive constant-power operating range is also desired. A new method to extend the operating range as well as to improve efficiency of IPMSM with adjustable PM armature flux linkage by means of adapting flux-shortening iron plates is proposed in this paper. The performance of the proposed IPMSM is studied by simulation and experiments. It shows that the operating range of the proposed IPMSM can be greatly extended by lowering the PM armature flux level with the iron plates. In flux-weakening control area, due to the possibility of decreasing the PM armature flux linkage, the proposed IPMSM requires less d-axis armature current. Therefore the efficiency can be improved, especially at light load and high speed operation.

   Periodic Torque Ripple Minimisation in PMSM Drive using ILC
By B.H. Lam; S.K. Panda; J.X. Xu [View]
[Download]

Abstract: PM synchronous motor drives are widely used for high-performance direct-drive servo applications where torque smoothness is an essential requirement. However, parasitic torque pulsations do exist in PMSM drive. These oscillations are due to the non-sinusoidal flux density distribution around the airgap, variable magnetic reluctance of the air-gap due to stator slots, residual DC offsets and scaling errors in phase current measurement. A consequence of these torque ripples is speed oscillations that deteriorate the drive performance particularly at low speeds. In this paper, we propose a simple modular iterative learning control (ILC) scheme which generates a compensation reference current based on the error between the desired and actual motor torques. When this compensation current is augmented with the main reference current, the resultant current reduces the periodic torque ripples. Being a modular unit the proposed ILC controller can be applied in conjunction with the conventional (open-loop) torque controller and therefore can be easily integrated to any of the existing PMSM drive system. Experimental test results obtained from a 1.2 kW PMSM drive system validates the effectiveness of the proposed ILC control scheme in reducing periodic torque ripples.

   Position-Sensorless Drive of the IPMSM for Wide Speed Range
By N. Nomura; A. Toba; T. Yamasaki; S. Ozaki; H. Ohsawa [View]
[Download]

Abstract: A novel position-sensorless drive with torque linear control for the interior permanent magnet synchronous motor (IPMSM) is presented in this paper. The system has full speed-range drive capabilities from zero to and over the base speed, which is a key requirement from the market. To save energy and to reduce the capacity of IPMSM drive system, some methods have been reported. However, it is difficult to realize these algorithms while controlling the torque, because of the nonlinearity between torque and current due to the IPMSM’s saliency. To cope with this problem, we propose a torque control method based on regulation of the load angle. The proposed control strategy has been experimentally tested by using three types of IPMSM, each having a different base speed. Stable sensorless operation over the whole speed range has been obtained, regardless of types of the motor. The system can drive IPMSM until to 7200[r/min], which is very high speed. Therefore, the system can be applied for wide uses.

   Reducing cogging torque in a permanent magnet motor
By E. Bozeva [View]
[Download]

Abstract: In a permanent magnet motor a cogging torque manifests itself by the tendency of the rotor to align in a number of stable positions when unexcited. Under dynamic conditions the resulting pulsating torque, of zero net value, may cause undesirable speed pulsation, and also may induce vibrations and acoustic noise. It is thus of great interest to get a deeper understanding of the cogging torque phenomenon and to find possible ways to reduce it. By means of advanced two dimensional field calculations a new design rule has been demonstrated for a rotor design with slot mounted or embedded magnets. If the quantity Në, the relative magnet width compared to the slot pitch, is chosen as an integer, the cogging torque will be significantly reduced by a factor of ten or more to less than 0.5% of the rated torque. This can also be given a physical explanation. The calculated results have been verified by experiments on two different motors. The agreement between measurements and calculations of the cogging torque as a function of the rotor angle is good both for an nonoptimized rotor design as well as for an optimal design with integer relative magnet width. The results are generally valid for motors with embedded permanent magnets. For motors with airchannels around the magnets, the value of the relative magnet width for minimum cogging torque somewhat deviates from an integer. One conclusion from the study is that the use of Maxwell stresses increases the calculation accuracy significantly compared to calculating the cogging torque from the change of magnetic energy and that the calculation of the torque should be made on the rotor surface or as near the surface as possible.

   Robust PI current control for a permanent magnet synchronous machine
By P-O. Nyman; W. Sulkowski; D. Samuelsen [View]
[Download]

Abstract: An LMI-based approach for design of a robust multivariable PI-type current controller for a permanent magnet synchronous machine is described. For given stator-parameter uncertainties the closed-loop poles remain in a pre-specified region, and cross-couplings between the d- and q-channels will uniformly stay below specified bounds across the parameter uncertainty range. The order of the controller remains the same as in the conventional setup with two scalar PI-controllers and a static decoupling.

   Speed Control of a PMSM. A comparative Study of Nonlinear Strategies
By J.A. Solsona; M. I. Valla [View]
[Download]

Abstract: This paper deals with speed control of Permanent Magnet Synchronous Motors (PMSM). Two different non-linear strategies are considered, Exact Feedback Linearization (FL) and a Passivity-Based control (PB). Both methods are compared regarding their complexity and their performance conerning tracking errors. The PB being simpler presents a coupled and nonlinear tracking error dynamics while the FL tracking error dynamics is linear and decoupled. Simulation results are presented in order to validate the comparison. They show a better performance of the FL.

   Starting of single-phase cageless synchronous motors
By P. Acarnley; A. Jack; B. Mecrow [View]
[Download]

Abstract: Single-phase line-start synchronous motors are an attractive alternative to universal and induction motors for cost-sensitive applications, such as domestic appliances. The application range is limited by the starting transient, so the paper presents a method for detailed analysis of this transient, together with a simplified semi-analytic approach, which is validated by comparison with experimental results.

   Very simple robust position control of PMSM using neural network
By J-S. Ko; S-K. Youn [View]
[Download]

Abstract: A very simple control approach using neural network for the robust position control of a Permanent Magnet Synchronous Motor (PMSM) is presented. The linear quadratic controller plus feedforward neural network is employed to obtain the robust PMSM system approximately linearized using fieldorientation method for an AC servo. The neural network is trained in on-line phases and a feedforward recall and error back-propagation training compose this neural network. Since the total numbers of nodes are only eight, this system easily is realized by the general microprocessor. During the normal operation, the input-output response is sampled and the weighting value is trained multi-times by error back-propagation method at each sample period to accommodate the possible variations in the parameters or load torque. And the state space analysis is performed to obtain the state feedback gains systematically. In addition, the robustness is also obtained without affecting overall system response. A floating-point Digital Signal Processor DS1102 Board (TMS320C31) realizes this method. This board provides a free 6.2'' length Industry Standard Architecture (ISA) slot with 16-bits connector. The basic DSP software is used to write C-program, which is compiled by using ANSI-C style function prototypes.

EPE 2001 - Topic 06a: Permanent Magnet Machines and Drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2001 - Conference > EPE 2001 - Topic 06: ELECTRICAL MACHINES AND ADJUSTABLE SPEED DRIVES > EPE 2001 - Topic 06a: Permanent Magnet Machines and Drives
	[return to parent folder]

	Design of a Compact BLDC Motor for Transient Applications By Y.K. Chin; W.M. Arshad; T. Bäckström; C. Sadarangani	[View] [Download]
Abstract: such as emergency breakers, protective devices in explosive environments, emergency exit openings etc. fall into a broad category that can be grouped under a general term transient applications. This paper presents a compact brushless permanent magnet (BLDC) motor design for those short time operations. Design procedures for both interior and exterior rotor BLDC configurations are described. Design analysis is verified by testing and building a prototype motor. It is found that the most critical design criterion is to avoid magnet demagnetisation. A thermal check on the design is always advisable although thermal loading is negligible.

	Design of low speed PM motors for ac inverter drives By T. Heikkilä; J. Pyrhönen; M. Niemelä	[View] [Download]
Abstract: Effective new control systems like Direct Torque Control (DTC) make it possible to introduce new high efficiency motors - such as permanent magnet synchronous motor (PMSM) - to this day’s demanding industry applications. Here a design of PMSM, which suits well to AC inverter drives are proposed.

	Design Steps towards a High Power Factor Transverse Flux Machine By P. Anpalahan; J. Soulard; H-P. Nee	[View] [Download]
Abstract: This article describes a topology of three-phase transverse flux machine and the derivation of an analytical model which does not exist in the literature. Three dimensional finite element analysis is also used to get more accurate results. Steps carried out to obtain a better power factor are presented.

	Encoderless IPM Drive System For EV/HEV Propulsion Applications By N. Patel; T. O’Meara; J. Nagashima; R. Lorenz	[View] [Download]
Abstract: This paper presents an accurate and robust method of estimating rotor position for an IPM (Interior Permanent Magnet) drive system for EV/HEV (Electric Vehicles/Hybrid Electric Vehicles) applications. The importance of encoderless technique for electric propulsion drives has been highlighted in the present study. Stability and dynamic behavior of the position estimation is critical in consumer-oriented traction applications. The paper provides experimental results, which demonstrate an excellent performance of the proposed control algorithm. The goal of this paper is to present an encoderless (or position sensorless) control method for EV/HEV propulsion drives which works over the entire torque-speed range including zero mechanical speed. The method combines two rotor position estimation techniques to fully cover both low (incl. zero) and high-speed ranges. Experimental results demonstrate excellent performance.

	High speed axial-flux permanent magnet machine By F. Sahin; A. Tuckey; A.J.A Vandenput	[View] [Download]
Abstract: The paper gives an overview of the design, and particularly manufacturing and testing of a 16000 rpm, 30 kW axial-flux permanent-magnet (AFPM) synchronous machine. This machine is mounted inside and as an integral part of a flywheel that will subsequently be used in a hybrid electric vehicle. The paper describes the testing facility and includes the measurement results in comparison with the calculations.

	Hybrid PI and fuzzy logic speed control of PM brushless ac drives By J. X. Shen; Z. Q. Zhu; D. Howe	[View] [Download]
Abstract: Speed controls with PI and fuzzy logic algorithms are implemented in a vector controlled PM brushless AC drive system. Parameters of the fuzzy logic controller are optimised while their influences are examined. Hybrid PI and fuzzy logic control is also proposed and implemented to achieve both excellent dynamic and steady state performances.

	IPM synchronous machine drive response to short circuit faults By B. A. Welchko; T. M. Jahns; W. L. Soong; J. M. Nagashima	[View] [Download]
Abstract: A closed-form solution is presented for the steady-state response of interior permanent magnet (IPM) synchronous machines to symmetrical short circuits including the effects of q-axis magnetic saturation. Machine response to single-phase asymmetrical short circuits is also investigated. Experimental data is presented to verify predicted behavior for both types of short circuits. It is shown that single-phase asymmetrical short circuit faults produce more severe fault responses with high pulsating torque and a significant threat of rotor demagnetization. A control strategy that purposely transitions such faults into symmetrical three-phase short circuits can minimize the fault severity and associated demagnetization risks. Implications for the design of IPM machines with improved fault tolerance are discussed.

	Measured performances of a new hybrid synchronous machine. By Y. Amara; E. Hoang; M. Gabsi; M. Lecrivain; A. H. Ben Ahmed; S. Dérou	[View] [Download]
Abstract: PM synchronous machines may operate over broad speed ranges at constant power thanks to the introduction of control laws that enable flux weakening. Generally, this control is accomplished by means of applying a strong demagnetizing current in the d-axis, yet such an approach engenders the risk of an irreversible demagnetization of the magnets and a reduction in machine performance. In this paper, we will present an original layout for the hybrid-excitation synchronous machine : an excitation by both magnets and coils. This solution allows for effective flux weakening without running the risk of demagnetizing the magnets.

	Modeling and Optimal Integration of a FPGA-Based Position Estimator fo By Y.A. Chapuis; Y. Kebbati; T. Kosaka; N. Matsui	[View] [Download]
Abstract: This paper present a FPGA solution for a fuzzy logic based-position estimator of a sensorless controller of fully-pitched winding reluctance motor drives. A modular architecture of a position estimator is proposed in order to reach flexible and optimization performances of integration. Indeed, IC design can increase the specificity of a digital controller by exploiting the parallelism presented in most algorithms. Moreover, this solution can reduce the cost of the implementation by only use the necessary hardware. The aim of the integration is to relieve and to speed up the DSP calculation tasks while improving control results A modular architecture approach is proposed by decomposing the general algorithm of the position estimator in specific module architectures. Afterwards, these modules which are designed, synthesized and valid by simulation from VHDL models. Behavior simulation results of the FPGA are obtained by post-simulation and delay retro-annotation using Altera components library. Hardware results of position estimator integration will be also done.

	New dead-time compensation using disturbance observer By H-S. Kim; H-T. Moon; M-J. Youn	[View] [Download]
Abstract: A new on-line dead-time compensation method for a permanent magnet (PM) synchronous motor drive is proposed. Using a simple disturbance observer without any additional circuits and off-line experimental measurements, disturbance voltages in the synchronous reference dq frame caused by the dead time and non-ideal switching characteristics of power devices are estimated in an on-line manner and fed to voltage references in order to compensate the dead-time effects. The proposed method is applied to a PM synchronous motor drive system and implemented by using software of a digital signal processor (DSP) TMS320C31. Experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed method.

	New Method for Efficiency Improvement of IPMSM By L. Ma; M. Sanada; S. Morimoto; Y. Takeda; H. Murakami	[View] [Download]
Abstract: Recent progresses in power electronic device, rare-earth permanent magnet (PM) and modern motor control technology have made it possible for interior permanent magnet synchronous motor (IPMSM) to find wider application. In the applications which require operation ability above base speed, such as electric vehicles and compressors, except for large torque performance at low speed, high efficiency in extensive constant-power operating range is also desired. A new method to extend the operating range as well as to improve efficiency of IPMSM with adjustable PM armature flux linkage by means of adapting flux-shortening iron plates is proposed in this paper. The performance of the proposed IPMSM is studied by simulation and experiments. It shows that the operating range of the proposed IPMSM can be greatly extended by lowering the PM armature flux level with the iron plates. In flux-weakening control area, due to the possibility of decreasing the PM armature flux linkage, the proposed IPMSM requires less d-axis armature current. Therefore the efficiency can be improved, especially at light load and high speed operation.

	Periodic Torque Ripple Minimisation in PMSM Drive using ILC By B.H. Lam; S.K. Panda; J.X. Xu	[View] [Download]
Abstract: PM synchronous motor drives are widely used for high-performance direct-drive servo applications where torque smoothness is an essential requirement. However, parasitic torque pulsations do exist in PMSM drive. These oscillations are due to the non-sinusoidal flux density distribution around the airgap, variable magnetic reluctance of the air-gap due to stator slots, residual DC offsets and scaling errors in phase current measurement. A consequence of these torque ripples is speed oscillations that deteriorate the drive performance particularly at low speeds. In this paper, we propose a simple modular iterative learning control (ILC) scheme which generates a compensation reference current based on the error between the desired and actual motor torques. When this compensation current is augmented with the main reference current, the resultant current reduces the periodic torque ripples. Being a modular unit the proposed ILC controller can be applied in conjunction with the conventional (open-loop) torque controller and therefore can be easily integrated to any of the existing PMSM drive system. Experimental test results obtained from a 1.2 kW PMSM drive system validates the effectiveness of the proposed ILC control scheme in reducing periodic torque ripples.

	Position-Sensorless Drive of the IPMSM for Wide Speed Range By N. Nomura; A. Toba; T. Yamasaki; S. Ozaki; H. Ohsawa	[View] [Download]
Abstract: A novel position-sensorless drive with torque linear control for the interior permanent magnet synchronous motor (IPMSM) is presented in this paper. The system has full speed-range drive capabilities from zero to and over the base speed, which is a key requirement from the market. To save energy and to reduce the capacity of IPMSM drive system, some methods have been reported. However, it is difficult to realize these algorithms while controlling the torque, because of the nonlinearity between torque and current due to the IPMSM’s saliency. To cope with this problem, we propose a torque control method based on regulation of the load angle. The proposed control strategy has been experimentally tested by using three types of IPMSM, each having a different base speed. Stable sensorless operation over the whole speed range has been obtained, regardless of types of the motor. The system can drive IPMSM until to 7200[r/min], which is very high speed. Therefore, the system can be applied for wide uses.

	Reducing cogging torque in a permanent magnet motor By E. Bozeva	[View] [Download]
Abstract: In a permanent magnet motor a cogging torque manifests itself by the tendency of the rotor to align in a number of stable positions when unexcited. Under dynamic conditions the resulting pulsating torque, of zero net value, may cause undesirable speed pulsation, and also may induce vibrations and acoustic noise. It is thus of great interest to get a deeper understanding of the cogging torque phenomenon and to find possible ways to reduce it. By means of advanced two dimensional field calculations a new design rule has been demonstrated for a rotor design with slot mounted or embedded magnets. If the quantity Në, the relative magnet width compared to the slot pitch, is chosen as an integer, the cogging torque will be significantly reduced by a factor of ten or more to less than 0.5% of the rated torque. This can also be given a physical explanation. The calculated results have been verified by experiments on two different motors. The agreement between measurements and calculations of the cogging torque as a function of the rotor angle is good both for an nonoptimized rotor design as well as for an optimal design with integer relative magnet width. The results are generally valid for motors with embedded permanent magnets. For motors with airchannels around the magnets, the value of the relative magnet width for minimum cogging torque somewhat deviates from an integer. One conclusion from the study is that the use of Maxwell stresses increases the calculation accuracy significantly compared to calculating the cogging torque from the change of magnetic energy and that the calculation of the torque should be made on the rotor surface or as near the surface as possible.

	Robust PI current control for a permanent magnet synchronous machine By P-O. Nyman; W. Sulkowski; D. Samuelsen	[View] [Download]
Abstract: An LMI-based approach for design of a robust multivariable PI-type current controller for a permanent magnet synchronous machine is described. For given stator-parameter uncertainties the closed-loop poles remain in a pre-specified region, and cross-couplings between the d- and q-channels will uniformly stay below specified bounds across the parameter uncertainty range. The order of the controller remains the same as in the conventional setup with two scalar PI-controllers and a static decoupling.

	Speed Control of a PMSM. A comparative Study of Nonlinear Strategies By J.A. Solsona; M. I. Valla	[View] [Download]
Abstract: This paper deals with speed control of Permanent Magnet Synchronous Motors (PMSM). Two different non-linear strategies are considered, Exact Feedback Linearization (FL) and a Passivity-Based control (PB). Both methods are compared regarding their complexity and their performance conerning tracking errors. The PB being simpler presents a coupled and nonlinear tracking error dynamics while the FL tracking error dynamics is linear and decoupled. Simulation results are presented in order to validate the comparison. They show a better performance of the FL.

	Starting of single-phase cageless synchronous motors By P. Acarnley; A. Jack; B. Mecrow	[View] [Download]
Abstract: Single-phase line-start synchronous motors are an attractive alternative to universal and induction motors for cost-sensitive applications, such as domestic appliances. The application range is limited by the starting transient, so the paper presents a method for detailed analysis of this transient, together with a simplified semi-analytic approach, which is validated by comparison with experimental results.

	Very simple robust position control of PMSM using neural network By J-S. Ko; S-K. Youn	[View] [Download]
Abstract: A very simple control approach using neural network for the robust position control of a Permanent Magnet Synchronous Motor (PMSM) is presented. The linear quadratic controller plus feedforward neural network is employed to obtain the robust PMSM system approximately linearized using fieldorientation method for an AC servo. The neural network is trained in on-line phases and a feedforward recall and error back-propagation training compose this neural network. Since the total numbers of nodes are only eight, this system easily is realized by the general microprocessor. During the normal operation, the input-output response is sampled and the weighting value is trained multi-times by error back-propagation method at each sample period to accommodate the possible variations in the parameters or load torque. And the state space analysis is performed to obtain the state feedback gains systematically. In addition, the robustness is also obtained without affecting overall system response. A floating-point Digital Signal Processor DS1102 Board (TMS320C31) realizes this method. This board provides a free 6.2'' length Industry Standard Architecture (ISA) slot with 16-bits connector. The basic DSP software is used to write C-program, which is compiled by using ANSI-C style function prototypes.