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In order to ensure the high precision and good dynamic characteristics of the dual‐axis linear motor when machining components, the tracking error and contour error should be reduced with more complex machining trajectory. In this study, the characteristic model of position control of the linear motor is established by using the modelling principle of the characteristic model, and the intelligent adaptive controller is designed. In addition, a new calculation method of the equivalent contour error is proposed innovatively, and the dual axis is compensated by proportional feedback control, to improve the contour accuracy of the permanent magnet synchronous linear motor dual‐axis control system. Finally, through the simulation and experiment of the dual‐axis motor platform, the effectiveness of the proposed contour error calculation method and the intelligent adaptive controller can make the dual‐axis motion control system have higher accuracy and strong robustness and can also make the motor run more smoothly. [ABSTRACT FROM AUTHOR]

Given the existence of detent force, the positioning accuracy of permanent magnet linear synchronous motor (PMLSM) with an iron core worsens in its application in the field of the precision drive. To address this problem, a method is proposed to weaken the detent force of PMLSM with a V‐shaped tooth‐slot structure. The models of the detent force, including the cogging force and end force, are established theoretically. The analytical expressions of cogging force and end force are obtained by analysing the ripple rule of the motor. Then, the tooth‐slot surface of the motor with the V‐shaped tooth‐slot structure conducts infinitesimal processing. The relationship between cogging force, end force, and the V‐shaped depth of the V‐shaped tooth‐slot PMLSM is deduced, respectively, using the integration method. Furthermore, Ansoft finite element simulation software Maxwell module is used to compare the conventional PMLSM, V‐shaped magnetic pole PMLSM, and V‐shaped tooth‐slot PMLSM. The comparison reveals that the V‐shaped tooth‐slot structure has the excellent characteristic of increasing the average value of thrust while reducing the ripple of thrust caused by detent force. Finally, prototype fabrication and experiments are conducted to verify the correctness and feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

Currently, AC motors are a key element of industrial and commercial drive systems. During normal operation, the machines may become damaged, which may pose a threat to the users. Therefore, it is important to develop a fault detection method that allows for the detection of a fault at an early stage. Among the currently used diagnostic systems, applications based on deep neural structures are dynamically developed. Despite many examples of applications of deep learning methods, there are no formal rules for selecting the network structure and parameters of the training process. Such methods would make it possible to shorten the implementation process of deep networks in diagnostic systems of AC machines. The article presents a detailed analysis of the influence of deep convolutional network hyperparameters and training procedures on the precision of the interturn short-circuits detection system. The studies take into account the direct analysis of phase currents through the convolutional network for induction motors and permanent magnet synchronous motors. The research results presented in the article are an extension of the authors' previous research. [ABSTRACT FROM AUTHOR]

The winding segmented permanent magnet linear synchronous motor (WS-PMLSM) generally adopts three-phase windings and the length of the segment is greater than that of the passive mover. This article proposes an innovative design for the module motor, using two-phase integrated single-layer concentric distributed windings, no half-filled slots, and the influence of the pulsating magnetic field generated by the segmented windings is negligible. By analyzing the transition of the segment winding, a variable parameter mathematical model is established, and proportional resonance (PR) control is introduced to eliminate the influence of parameter changes on the model. Meanwhile, the concept of a multiphase motor is introduced for pass-through segment control, with the help of the double $\alpha $ – $\beta $ coordinate transformation method, a new effective coil selection and switching algorithms is constructed, and the thrust forces for the pass-through section are obtained. It is experimentally confirmed that this design is in line with the production. [ABSTRACT FROM AUTHOR]

Unavoidably, the controlsystem of any permanent magnet synchronous motor (PMSM) is subjected to perturbations, e.g., motor nonidealities and inverter nonlinearities. To reject these perturbations, a new super-twisting (ST) control variant, called speed adaptive super-twisting (S-AST) control, is proposed in this paper. In the S-AST control, a proportional-integral (PI) and a ST controllers are merged using an adaptive law that is based on the motor speed measurement. This is done to reduce the chattering problems that the standard ST control presents. In addition, a mathematical design for the S-AST control is proposed, where the relationship between the chattering amplitude, the switching frequency and the system perturbations is shown. The main contribution in this paper is the application of the S-AST controller to reduce the total harmonic distortion (THDi) of the PMSM currents. By comparing the S-AST control against PI control, the THDi is reduced from 9.9% to 1.27%, in simulation, and the THDi is reduced from 22.79% to 1.56%, experimentally. These results demonstrate how the S-AST control is an excellent alternative to improve the waveform of the PMSM currents. [ABSTRACT FROM AUTHOR]

A predictive current controller is established based on the system model and, therefore, suffers from the problems, such as parameter mismatches, digital delay, and external disturbances. In order to tackle these problems, an observer-based robust predictive current control strategy is proposed in this article, which employs an extended state observer to estimate the disturbances, currents, and applies the augmented system model for the design of the controller. It is generally formulated and applicable to any ac motor drive system as long as the prerequisites are satisfied. Furthermore, the proposed control scheme is proven to be input-to-state stable with a proper design of the controller and the observer. The effectiveness of the proposed control strategy is moreover verified with numerous experiments on a dSPACE system under various test scenarios. The comparative studies between the proposed method and the predictive current control approaches, i.e., the conventional deadbeat control and the continuous control set model predictive control, are conducted at different operating conditions. [ABSTRACT FROM AUTHOR]

An 8-pole 48-slot dual three-phase synchronous reluctance motor has been tested under half control mode, that is, when only a single three-phase system is supplied while the other is not operating. Changing the terminal connections of the motor prototype available, two different winding configurations have been tested. This allows their performances to be experimentally compared. At first, the cross coupling effect between the axis in $dq$ reference is analyzed, by measuring the flux linkages for different current combinations. The torque characteristics are compared in terms of torque map, maximum torque capability and torque ripple. Then the finite element analysis has been used to explain the experimental results and to investigate the radial forces on the rotor. Finally, the impact of a lack of symmetry between the two three-phase system is investigated. [ABSTRACT FROM AUTHOR]

High‐frequency audible noise and high‐frequency vibrations (HFVs) in electrical vehicles are primarily caused by vibrations and ripples generated in the traction motor. The appositeness of permanent magnet synchronous motors (PMSMs) has been boosting in traction applications due to their high energy density, compact size and high torque to weight ratio. A novel and step‐by‐step design of medium power, high speed, surface PMSM, suitable for e‐bus or e‐truck applications, with suppressed torque ripples, is presented. Initially, a conventional machine design approach has been used to design 100 kW PMSM. In the next step, the design has been ameliorated by making it a fractional slot winding machine to suppress the winding harmonics. Finally, the effect of the permanent magnet embrace size on the torque ripple has been investigated. A nonlinear relationship between the torque ripple and PMSM magnetic embrace has been developed. The developed relationship has been validated in the finite element model of the machine. Gradient‐based nonlinear sequential programming has been used to find out the optimum magnetic embrace for the minimised torque ripple. The effectiveness of the optimised design has been revalidated in the FE software. The step‐by‐step design process described here can reduce the torque ripple by 85% of optimised design compared to the conventionally designed PMSM. [ABSTRACT FROM AUTHOR]

Minimization or elimination of cogging torque is a significant issue in permanent magnet (PM) motor design process. There are some design techniques to reduce or eliminate this unwanted torque components in PM motors. This paper focuses on two different design techniques, varying magnet pole-arc and step-skew, to reduce cogging torque component in radial flux PM synchronous motors. Different design points which consider pulsating torque components and back-EMF harmonics are obtained via finite element analysis (FEA) for a low power industrial PM motor. A prototype motor is manufactured for one of the desired designs and is tested experimentally. Good agreement is attained between the analysis and experimental results. [ABSTRACT FROM AUTHOR]

This article proposes a current-scaling gain-compen-sation algorithm for motor drive applications under the locked-rotor condition. In heavy industrial applications, such as elevators and cranes, initial commissioning tests are performed with the rotor locked. To compensate for errors in the current-scaling gain, the proposed method controls the current in the d–q axis using two-phase current-sensing methods in a stationary reference frame. The three-phase scaling gains are then estimated using the resulting d-axis current command and output voltage and are compensated for using these estimations. The proposed method delivers accurate compensations by considering the inequality between phase resistances. The effectiveness of the proposed algorithm is verified through simulations and experiments. [ABSTRACT FROM AUTHOR]

In this article, a new online continuous control set-predictive controller (CCS-PC) is proposed with the objective of minimizing the stator-flux and torque ripples. In this controller, a constrained optimization problem is constructed to optimize the phase, amplitude, and time duration of the voltage vector applied to the motor. Fast Iterative Shrinkage-Thresholding Algorithm (FISTA) which is an advanced algorithm based on fast proximal gradient method is adopted to find the optimal solution in an online manner. In each control period, FISTA is executed 10 times where the voltage vector found in the last iteration is considered as the optimal voltage vector. Performance of the proposed controller is compared with the performance of an offline CCS-PC through various experiments. In these experiments, stator-flux ripple, torque ripple, stator-current total harmonic distortion, and computational complexity of the controllers are compared with each other. Based on the results, pros and cons of the proposed online CCS-PC are highlighted. [ABSTRACT FROM AUTHOR]

This paper offers methods to analyze the performance of three-phase synchronous machines operating with an unsymmetrical stator winding caused by cutting out and bypassing coils. The resulting unsymmetrical current distribution in the stator winding tends to produce overheating in parts of the stator and damper windings at full load as well as torque pulsations. Thus, the main objective of this study is to determine the maximal load, under which the unsymmetrical machine may operate without exceeding the permissible temperature limit. Based on the multiloop method, a mathematical model of a synchronous machine with missing coils in the stator winding is developed. In order to determine the current distribution, the machines’ system of differential equations is solved by using a numerical integration method (Runge–Kutta method). As an alternative method, the system of differential equations in the steady state is reduced to a system of algebraic equations, which can be solved with the Gaussian elimination method. Both methods are validated by the measurement results of a 25-kW salient pole synchronous machine. Furthermore, both the circulating current within the parallel branches and the line currents of the different phases as a result of coil or coil group cut-outs are analyzed for a large 41-MW cylindrical rotor synchronous motor. [ABSTRACT FROM AUTHOR]

This paper proposes the novel scalable saturated model of synchronous permanent magnet machines, which combines ultrafast scaling laws with a saturated flux-linkage and loss model. The scalable model is used for the fast and accurate calculation of efficiency/loss maps and can also be used for drive cycle analysis including the calculation of energy consumption. It is verified by comparison with an existing state-of-the-art efficiency map and drive cycle analysis software. Additionally, an experimental verification of a saturated flux-linkage and loss model is presented. The additional possible usage of the scalable model is to find the optimal size of a scaled machine in order to meet the drive cycle performance and requirements of a traction motor. [ABSTRACT FROM AUTHOR]

In this paper, the influence of saturation and cross-coupling effects on the copper loss minimization for synchronous machines with strong saliencies, especially the permanent-magnet-assisted synchronous reluctance machines and reluctance synchronous machines are analyzed. It is shown that state-of-the-art methods for saturation consideration through the absolute inductances fail for these machines. A novel method for maximum torque per ampere estimation, which includes the consideration of these effects through the use of differential inductances, is proposed and its effectiveness is shown through finite-element analysis and experiments. [ABSTRACT FROM AUTHOR]

In this paper, an improved predictive torque control without weighting factor is proposed for a voltage source inverter-permanent magnet synchronous motor drive system, which possesses good control performance of torque and stator flux. By investigating the relationship among torque, the reference stator flux amplitude, and the phase angle of the stator flux, the reference stator flux vector is constructed. Then, the reference voltage vector is calculated by the reference stator flux vector based on the delay compensation and the deadbeat control. The extended control set is designed and two generalized base vectors that require further screening are determined based on the position of the reference voltage vector to improve the calculation efficiency. And the duty ratios used for the generalized base vectors are calculated, according to the geometric relations between the generalized base vectors and the reference voltage vector. Finally, by the duty cycle control between two generalized base vectors and between each generalized base vector and zero vector, the candidate vectors are gained and substituted into the cost function only with the flux vector error term. Experiment tests were carried out and the results validated the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper investigates the use of the Taguchi method for the design of line-start permanent magnet synchronous motors (LS-PMSMs). To address the inherent limitation of the Taguchi method in solving multiresponse optimization problems, an improved regression rate methodology and a weighted factor multiobjective technique are incorporated to form a Taguchi method based multiobjective design framework. To validate the proposed method, a prototype machine has been designed, constructed, and experimentally evaluated. It shows that the proposed method can effectively take into account both steady-state and transient synchronization performances in the design of LS-PMSMs. [ABSTRACT FROM AUTHOR]

Reliable and safe operation of electric motors in the industry is highly desirable. Accurate modelling is the first step in developing a diagnostic tool for different types of failures. This study presents a generalised dq-model for interior-mount line start permanent magnet synchronous motors under asymmetrical stator phase's windings. The presented dq-model has been derived using winding theorem. Implementation and simulation of the derived dq-model has been done using MATLAB/ SIMULINK software. For validation purposes, interior-mount line start permanent magnet synchronous motor (LSPMSM) under this fault condition is implemented using the JMAGTM-finite-element-based software. The performance of a 1-hp interior-mount LSPMSM motor under different loading levels and stator winding asymmetric conditions has been investigated using the simulated MATLAB and JMAG models. Simulation results of MATLAB and JMAG are in very good agreement and show that under asymmetrical stator winding condition, oscillations are obvious in the torque characteristics of the motor. In addition, the torque experience high oscillations at a steady state due to the asymmetry between stator phases. Finally, investigating torque frequency spectrum showed that they can be good signatures in diagnosing asymmetrical stator winding faults in interior-mount LSPMSM. [ABSTRACT FROM AUTHOR]

In this paper, we propose a goodness factor that shows how the output density of a Spoke-type permanent-magnet synchronous motor (PMSM) is improved than that of the conventional surface permanent-magnet synchronous motor (SPMSM). The application of the goodness factor, which is defined as the ratio of the total flux between different motor configurations, enables a comparison of the total flux between the SPMSM and spoke-type PMSM. A performance comparison analysis between the two motor configurations with the same rotor diameter, air gap length, stack length, permanent-magnet usage, and materials was performed using the proposed goodness factor. In order to improve the performance prediction accuracy, furthermore, the effect of both the bridge leakage and the axial leakage was included during the analysis process of the spoke-type PMSM. Finally, in order to verify the proposed method, SPMSM and Spoke-type PMSM with the same outer diameter size and permanent-magnet usage were fabricated and evaluated. [ABSTRACT FROM AUTHOR]

After designing and optimizing an electric machine, efficiency maps are needed to predict a vehicle’s performance in a dynamic simulation. Calculating efficiencies at various torque and speed points, however, requires prior knowledge of the input excitation conditions, such as the current magnitude and advance angle, in an electromagnetic finite-element analysis simulation. Hence, this paper derives and uses nonlinear motor control equations (MTPA, FW, MTPV) in the study of efficiency map calculation while accounting for both saturation and cross-coupling effects. Two synchronous ac motors are considered in this paper, including the 2010 Prius IPM and a PM-assisted synchronous reluctance machine, with all procedure steps outlined in detail. [ABSTRACT FROM AUTHOR]

It was recently demonstrated that the synchronous reluctance motor is well suited for electric as well as for hybrid electric vehicles. This paper deeply investigates the capabilities of a synchronous reluctance motor and compares them with those of a permanent-magnet-assisted synchronous reluctance motor, according to the typical requirement of a traction application. A proper rotor design is necessary. The average torque is due to the rotor anisotropy. The permeance difference between the direct- and the quadrature-axis is achieved by means of a high number of flux barriers. The position of the flux barrier ends and proper rotor asymmetries are chosen so as to reduce the torque ripple, mainly due to the slot harmonics. The impact of the rotor design on the motor performance is presented deeply, showing several simulation and experimental results, carried out on synchronous reluctance motors with different rotor geometries. Permanent magnets can be inset in the flux barriers to assist the synchronous reluctance motor improving its capabilities, but avoiding to use rare-earth permanent magnets. The main advantages of the permanent magnet assistance is an increase of the main torque density and of the power factor. They are evaluated experimentally. However, the drawback of adopting permanent magnets is the possible demagnetization of the magnets themselves. This can greatly limit the maximum overload capability of the motor, which is a salient requirement of a traction motor. [ABSTRACT FROM AUTHOR]

In the oil and gas industry, large synchronous motors are used to drive water injection pumps to support the pressure of a reservoir and to maintain the production level of a reservoir over a longer period. Therefore, failures in such motors will have an adverse impact on operation and production. Even though synchronous motors are superior to induction motors in relation to system voltage regulation and power factor correction, their starting is more complicated. As a result, the application of synchronous motors requires careful engineering analysis in the design stage of a project to determine system requirements for a successful operation. This paper presents a failure analysis case study for three 11 000-hp synchronous motors at a gas–oil separation plant along with the starting issues faced prior to the occurrence of a permanent damage. The fundamentals of dynamic motor acceleration requirements to achieve a successful start will be reviewed. In addition, results of site measurements and subsequent computer simulation will be presented. The simulation results were substantiated by a failure root cause analysis report provided by the manufacturer. This paper also discusses the obstacles faced as a result of erroneous and limited data availability, and the approach to overcome such difficulties. [ABSTRACT FROM AUTHOR]

In this paper, an investigation into an alternative topology for reluctance synchronous machine rotor flux barriers is presented. The investigated topology employs a high number of flux barrier variables with an alternative asymmetric rotor structure. The focus in this paper is on maximizing average torque and minimizing torque ripple, using finite element-based design optimization, in order to study the possibility of achieving acceptably low torque ripple. A subsequent investigation into the effect of rotor skew on the proposed optimized design to reduce torque ripple even further is also conducted, as well as the manufacturing and testing of the proposed flux barrier prototype. [ABSTRACT FROM PUBLISHER]

This paper describes a $d$– $q$-axis model of synchronous permanent-magnet machines at high frequency. Both the inductive and resistive saliencies are taken into account, and the model is suitable for investigating the self-sensing capability of the machines. It is proved that the high-frequency machine response can be described by means of three complex parameters, which form a symmetrical matrix. It is also shown that the high-frequency resistances between the $d$- and $q$-axes exist, and they may assume a negative value. Experimental results are included in this paper to prove the developed theory. [ABSTRACT FROM PUBLISHER]

The direct torque control (DTC) technique of a permanent magnet synchronous motor (PMSM) has received increasing attention due to its simplicity and robust dynamic response compared with other control techniques. The classical switching table based DTC presents large flux, torque ripples and more mechanical vibrations in the motor. Several studies have been reported in the literature on classical DTC. However, the studies that actually discuss or evaluate the classical DTC are limited. This paper proposes, an alternative DTC method/switching table for PMSM, to reduce flux and torque ripples as well as mechanical vibrations. This is achieved by a simple modification in the classical DTC structure, by eliminating the two level inverter available in the classical DTC and replacing it with a three level neutral point clamped inverter. To further improve the performance of the proposed DTC, the available 27 voltage vectors are allowed to form different groups of voltage vectors such as Large - Zero, Medium - Zero and Small - Zero. Based on these groups, a new switching table is proposed. The proposed DTC is compared with the classical DTC and existing literature from the aspects of theory analysis and computer simulations. It can be observed that the proposed technique can significantly reduce the flux, torque ripples, and mechanical vibrations and improves the quality of current waveform compared with traditional and existing methods. [ABSTRACT FROM PUBLISHER]

This paper presents a new topology of parallel hybrid excitation machine (PHEM), which integrates permanent-magnet synchronous motor (PMSM) and variable-reluctance machine, namely, doubly salient electromagnetic machine (DSEM), and provides a solution to better field-regulating capability. The configuration and the operation principle of the proposed PHEM are introduced. The combination criterion and design consideration are discussed. The performances of the two axial sections (PMSM and DSEM) are studied by 2-D finite-element analysis (FEA), respectively, to achieve reasonable integration. The field and voltage regulation capability of the PHEM is further investigated by 3-D FEA. A prototype PHEM is designed, manufactured, and tested. The measured results verify structural validity and finite-element predictions. The loss is predicted, and the measurement of short-circuit current illustrates the capacity of deexcitation at fault. The results confirm that the PHEM achieves effective power superposition of two different brushless machines. Bidirectional field-regulating capability facilitates a wide field regulating range of 6.5:1 under no load. [ABSTRACT FROM PUBLISHER]

This paper presents an improved fuzzy logic controller (FLC) for a permanent magnet synchronous motor (PMSM) for high performance industrial drive applications. The performance of the PMSM using proportional plus integral (PI) controllers and general fuzzy controllers are poor under load disturbances and transient conditions. The FLC is developed to have a smaller computational burden which makes it suitable for real time implementation, particularly at constant speed operating conditions. Hybrid control has the advantage of integrating a superiority of two or more control techniques for better control performances. A fuzzy controller offers better speed responses for startup and large speed errors. If the nature of the load torque is varied, the steady state speed error of the PMSM drive with an FLC becomes significant. To enhance the performance of the system, a new control method, hybrid fuzzy PI control and accelerated fuzzy PI control is proposed. The effectiveness of the proposed method is verified by a simulation based on MATLAB. The proposed hybrid fuzzy controller has good adaptability over load toque variation and can maintain constant speed. [ABSTRACT FROM PUBLISHER]

In this paper, an adaptive controller is developed to suppress chaos and track the desired speed in an uncertain chaotic permanent magnet synchronous motor (PMSM) drive system. The controller consists of computational and supervisory control schemes. The computational controller, based on fuzzy neural networks, is used to approximate the unknown nonlinear control signal, while the supervisory controller is employed to attenuate the approximation error effects of the neural network and ensure the system is robust. Simulation results demonstrate that the proposed controller can successfully quash chaotic oscillation in a PMSM and allow speeds to follow the desired trajectory despite the existence of uncertainties. [ABSTRACT FROM PUBLISHER]

The introduction of state equation model of the electrical machine based on direct and quadrature axes variables has paved the way for powerful control theories to be brought to bear on the problem of control of electric machines. Exact linearization has been applied to the control of permanent magnet synchronous motor (PMSM). In this paper, application of approximate linearization is proposed for the control of PMSM. Since the PMSM model is essentially quadratic, quadratic linearization is considered for the application. Conditions on the coordinate transformation and state feedback are derived for the linearization of a four dimensional permanent magnet (PM) machine model. The proposed linearization technique does not introduce singularities in the system as in the case of exact linearization. Also, to account for higher order nonlinearities including unmodelled dynamics, the linear zing transformations are adaptively tuned. Simulation studies verify the theoretical results presented. Hardware/software implementation is carried out to verify the effectiveness of the linearization technique proposed. The linearization technique proposed can also be applied to other types of electrical motors. [ABSTRACT FROM AUTHOR]

An equivalent dq model of three-phase flux-switching synchronous motors employing a segmental rotor is constructed and tested for predicting steady-state performance. Both the wound-field and permanent-magnet excited motors are represented. The unconventional topologies of the two types of motors present significant departure from the basic assumptions of the dq theory, even though the motors may be operated from a drive incorporating generic dq control regimes. The equivalent dq inductances and flux linkages are calculated from finite-element simulation results and applied in predicting the steady-state performance of the motor. It is found that the credibility of the dq model to predict the performance of the motors over the operating range is assured and is enhanced by incorporating dq-coupling inductances in the model. [ABSTRACT FROM PUBLISHER]

This paper proposes a sensorless speed control strategy for a permanent-magnet synchronous motor (PMSM) based on a new sliding-mode observer (SMO), which substitutes a sigmoid function for the signum function with a variable boundary layer. In order to apply a sensorless PMSM control which is robust against parameter fluctuations and disturbances, a high-speed SMO is proposed, which estimates the rotor position and the angular velocity from the back EMF. In the conventional SMO, a low-pass filter and an additional position compensation of the rotor are used to reduce the chattering problem that is commonly found in the SMO using the signum function. In order to overcome the time delay caused by the low-pass filter, in this research, a sigmoid function is used for the switching function instead of the signum function. Also, the variation in the stator resistance is estimated to improve the steady-state performance of the SMO. The stability of the proposed SMO was verified using the Lyapunov second method to determine the observer gain. The validity of the proposed high-speed PMSM sensorless velocity control has been demonstrated with simulations and real experiments. [ABSTRACT FROM AUTHOR]

In this paper, a novel stator main winding structure of a middle-point-current-injection-type bearingless permanent-magnet synchronous motor is proposed. Unlike the conventional bearingless motor consisting of both main motor windings and radial force control windings in the same stator, this special motor has only motor stator windings and no radial force stator windings. Only middle-point terminals are needed in the motor stator windings to inject currents. The principle of operation and its special structures are briefly described. The effectiveness of the proposed bearingless motor is presented with respect to conventional bearingless motors. Test results of a laboratory prototype machine highlighting vibration suppression are also presented. [ABSTRACT FROM PUBLISHER]

An optimal design procedure is proposed to effectively reduce the torque ripple by optimizing the rotor pole shape of the spoke-type IPMSM with concentrated winding. The procedure is composed of two steps. In step 1, the steepest descent method (SDM) is used with only two design variables to rapidly approach the optimal shape. From the near optimal rotor shape as a result of the step 1, the design variables are reselected, and the drawing spline curves are utilized to explain more complex shape with the Kriging model in step 2. By using an optimal design procedure, we show that the optimized rotor pole shape of the spoke-type IPMSM effectively reduces the torque ripple while still maintaining the average torque. [ABSTRACT FROM AUTHOR]

Small industrial three-phase induction motors (IMs) normally suffer from poor operational efficiency and power factor. This paper presents a high-performance line-start permanent magnet synchronous motor (LSPMSM) which is developed by simple modifications of an off-the-shelf small industrial three-phase IM with minimized additional costs. Two-dimensional (2-D) dynamic finite element analysis (FEA) models are employed to assess the machine performances, which are validated by comprehensive experimental results. The experimental comparisons between the amended LSPMSM and the original IM have indicated that significant improvements in efficiency and power factor can be achieved by the proposed LSPMSM. [ABSTRACT FROM AUTHOR]

Compared to the traditional steam catapult systems, the electromagnetic launch (EML) system with the permanent magnetic linear synchronous motor (PMLSM) has the features such as high efficiency, high power density and controllability, thus PMLSM is used in the EML system. In this paper, the long primary short secondary PMLSM used in electromagnetic launch system is designed, whose winding in the primary is divided into two sections. The control system employs two inverters and two current trackers, and the latter are adopted to track the 3-phase currents in the other section when the mover is in the cross section, so as to make the magnetic traveling field excited by the two windings move forward smoothly, and the thrust stable. With regard to the system nonlinearity and model variation, the fuzzy PI regulator is designed to adjust the mover velocity. In contrast to the conventional PI regulator, the simulation results show that the thrust is stable at section transition and the velocity reaction is quick without overshoot. The scheme proposed here is validated by the simulation results. [ABSTRACT FROM AUTHOR]

In this paper, a model for permanent magnet synchronous motors to deal with high-frequency emissions from an inverter system is proposed and analyzed. The model permits study of the common-mode (CM) effects on the motor line currents. The experimental measurements show that the CM stray capacitors are not affected by rotor magnet positions. The simulated and experimental results show that the CM currents increase with decreasing sampling time. [ABSTRACT FROM AUTHOR]

This paper deals with the maximum torque and speed of permanent-magnet synchronous motor (PMSM) drives when the inverter output voltage is filtered by an LC filter with a cutoff frequency well below the switching frequency. According to steady-state analysis, the filter affects the performance of the motor drive, especially at high speeds. The stator current is not equal to the inverter current, and due to the inverter current and inverter voltage limits, the torque-maximizing stator current locus differs from that of a drive without the filter. A field-weakening method is proposed for PMSM drives with an inverter output filter. The method is implemented and tested in a 2.2-kW PMSM drive. The experimental results agree well with the analysis, and validate the high- speed performance of the proposed field-weakening method. [ABSTRACT FROM AUTHOR]

In this paper, first, the effect of the interior permanent-magnet synchronous-motor (IPMSM) stator resistance to the maximum available motoring or regenerative braking torque is clarified. Then, a drive operating point is interpreted geometrically as the intersecting point of the torque-demand curve with either the maximum torque per ampere (MTPA) trajectory or the voltage-constraint curve inherently imposed by the motor and inverter under different control modes. Based on this principle, a novel voltage-constraint- tracking (VCT) field-weakening control scheme for IPMSM drives is proposed. The proposed method can automatically determine the desired MTPA or field-weakening control modes and provide a smooth transition between these two modes. No machine parameters are required in the field-weakening control mode, and no dc-link voltage sensor is used, rendering the proposed scheme rather robust. In addition, the minimum copper- loss operation can be preserved in the VCT-based control to achieve high efficiency. The proposed control method has a simple structure so that it can easily be implemented by modifying a conventional vector-controlled drive system for practical applications. Finally, a DSP-based prototype drive is constructed to verify the feasibility of the proposed scheme, and some experimental results are provided to demonstrate the satisfactory features. [ABSTRACT FROM AUTHOR]

In this paper, a newly designed instantaneous-torque-control scheme with improved instantaneous-torque estimation and control characteristics in a direct-drive permanent-magnet synchronous motor (DD-PMSM) is presented. A hybrid control structure that combines the internal-model principle and the variable-structure control approach is proposed. The appropriate control voltage vector is determined using the control effort of the variable-structure torque and d-axis current controllers combined with the estimated dynamic back-EMF vector in a feedforward control manner. Subsequently, the dynamic back-EMF vector, which contains the flux-harmonics information, is included in the reference voltage generation as an internal model. As a result, better disturbance rejection can be obtained with the proposed cascaded control structure. To robustly obtain the instantaneous-torque information, an adaptive motor model is proposed. The adaptive model is realized by adopting recursive estimators to estimate unknown machine electrical quantities and parameters. In addition to its robust estimation performance, the proposed adaptive model includes the dynamic model of the estimated disturbance to enhance the estimation characteristics. Experimental results are presented to demonstrate the validity and effectiveness of the proposed instantaneous-torque-control scheme. [ABSTRACT FROM AUTHOR]

This paper proposes new practical optimal current control methods for a newly emerging class of synchronous motors with hybrid rotor fields by both permanent magnet and winding. In a practical situation with limited voltage, the extensively used permanent-magnet synchronous motor hardly achieves an ideal performance in an energy-efficient manner due to its constant magnet field, which simultaneously allows both low-speed high-torque and wide speed-range operations. The hybrid-field synchronous motors (HFSMs) are potential candidates that can achieve the ideal performance as practical motors with control- lable hybrid rotor field. HFSMs can dynamically control the rotor flux according to the operation requirements by the low-speed, high-torque, and wide speed-range operations, etc. For the HFSMs, the same torque can be produced by a variety of stator and rotor currents due to the nonlinearity between the torque and the currents. Produced losses and required voltages depend upon the associated currents. Consequently, in the situation that current control systems are well constructed, appropriate determination of a set of stator and rotor current commands plays a key role to achieve the ideal performance in an energy-efficient manner. The proposed methods determine the current commands corresponding to a given torque command such that the total winding copper losses due to the stator and rotor currents can be minimized if the exact currents associated with the torque command exist; the best approximate torque can be produced if no exact associated currents exist, which is, of course, under the circumstance of a voltage limitation. The determined current commands are optimal in the sense of energy efficiency or degree of approximation under voltage limitation. New recursive algorithms searching the optimal current solution in real-time are also given as parts of the methods. The proposed methods are analytical but practical, whose usefulness is verified through experiments. [ABSTRACT FROM AUTHOR]

This paper describes a novel instantaneous torque control scheme for a high-performance direct-drive permanent- magnet synchronous motor. The scheme consists of a robust adaptive instantaneous torque observer and a hybrid-type variable-structure instantaneous torque controller. First, to robustly obtain the instantaneous electromagnetic torque information, a robust adaptive torque observer is designed by considering all possible current model uncertainties. The observation gains and uncertainties prediction rules are derived in the sense of Lyapunov theory so that the stability of the proposed estimation scheme is fulfilled. Second, to ensure perfect tracking of the output torque and providing means in eliminating torque ripples, the frequency modes of the disturbances to be eliminated should be included in the stable closed-loop system. To achieve this objective, a hybrid-type variable-structure controller with internal model, for the flux harmonics and system uncertainties, is adopted. The hybrid controller shows better disturbance rejection without control chattering. Comparative evaluation results are presented to demonstrate the validity and effectiveness of the proposed instantaneous torque control scheme. [ABSTRACT FROM AUTHOR]

This paper presents a novel direct instantaneous torque and flux controller with an adaptive linear neuron (ADALLNE)-based motor model for a high-performance direct drive permanent magnet synchronous motor (DD-PMSM). Usually, high-performance motor drives are characterized by their fast and accurate response, quick recovery from disturbances, and insensitivity to parameter variations. However, the absence of the auxiliary mechanisms in direct drives, such as gears or ball screws, increases the sensitivity of the servo performance to uncertainties in the drive system. Practically, uncertainties are usually composed of torque ripple, parameter variations, external disturbances and un-modeled dynamics. To achieve fast and smooth torque production in a DD-PMSM, the proposed controller has a linear with variable-structure control element to control the torque angle increment and a dynamic internal model element within the flux control loop. With this novel configuration, the controller can embed more frequency modes within the stable closed loop system to cancel the torque ripples. To relax the parameters sensitivity issue, this study proposes an ADALINE-based motor model to robustly extract the instantaneous torque information and unknown motor parameters with low computational demand and high accuracy. Comparative experiments are presented to demonstrate the validity and effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

This paper describes a new method to estimate the standstill position of permanent-magnet synchronous motors (PMSMs). The method is based on the anisotropic properties of permanent magnets and is therefore referred to as a magnetic anisotropy method (MAM). It differs significantly from all standard standstill position detection methods previously presented in the literature. It is totally independent of saliency and saturation effects and can therefore be used in many types of PMSMs where the standard methods would fail. The paper fully explains the experimental results and briefly analyzes the physical phenomena behind the method. [ABSTRACT FROM AUTHOR]

Recently, permanent-magnet-type linear synchronous motors (PM-LSMs) have been used as a driving source of transportation systems, to satisfy requirements such as speeding up of transportation systems and also to simplify maintenance. The authors' laboratory has proposed a stationary discontinuous primary PM-LSM in which the primary is engaged only when accelerated and decelerated operation is necessary, in order to resolve the problem of higher costs, when PM-LSM is used with long-distance transportation systems in factories. However, the stationary discontinuous primary PM-LSM contains the outlet edges which always exist as a result of the discontinuous arrangement of the primary. These edges become a problem, because the cogging force that they exert influences the controllability of the motor. This paper presents the results of an experimental examination and three-dimensional (3-D) numerical analysis by the finite-element method (FEM) of the cogging force exerted by the outlet edge. Moreover, we deformed the shape of the primary to decrease the cogging force at the outlet edge, and the results are examined using 3-D numerical analysis by the FEM. [ABSTRACT FROM AUTHOR]