Search

This paper presents the efficiency improvement of a pole-changing vernier machine (PCVM) by considering the residual magnetic flux density ( B r ) of low coercivity force (LCF) permanent magnets (PMs). The PCVM operates in two modes: vernier machine (VM) mode and permanent magnet synchronous machine (PMSM) mode, achieved through pole-changing. Pole-changing involves reversing the magnetic flux direction of LCF PM to alter the number of rotor pole pairs. By changing the number of rotor pole pairs, the PCVM operates as a VM mode at low speeds, providing high torque, and as a PMSM mode at high speeds, offering high efficiency. To achieve this, a combination of high coercivity force (HCF) PM and LCF PM is utilized in a single structure. The magnetic flux direction in the LCF PM is determined by B r , and the highest efficiency is achieved when B r reaches its maximum value | B r m |. This paper focuses on improving efficiency by obtaining B r m in VM mode and − B r m in PMSM mode through the design process. Additionally, finite element analysis (FEA) is employed to compare the performance of the improved model, which considers B r , with that of the conventional model, designed without considering B r . The improved model achieves higher B r values in each mode compared to the conventional model, resulting in increased torque density. Consequently, this leads to improved efficiency. [ABSTRACT FROM AUTHOR]

In this study, a torque enhancement principle for a stator permanent-magnet (PM) Vernier machine with a consequent pole structure is proposed. The novelty of the manuscript is the explanation of how stator PM Vernier machines benefit from consequent pole structure. Although a similar concept of stator PM Vernier machines with a consequent pole structure has been investigated in previous studies, a clear torque enhancement principle was absent. The keys to torque enhancement are the decrement of nonworking harmonics and increment of working harmonics. To demonstrate these phenomena, the torque contributions from the harmonics were calculated. Subsequently, the performances of the conventional machine and consequent pole machine were compared to verify the enhancement principle. The electromagnetic performances, including the back electromotive force and torque, were compared. The results show that the stator PM Vernier machine benefits significantly from torque enhancement using the consequent pole structure, and the torque enhancement principle was verified. [ABSTRACT FROM AUTHOR]

In this paper, the reluctance torque is utilized for improving the starting and average torques of a conventional brushless wound field synchronous machine (BL-WFSM). The conventional BL-WFSMs have an inherent issue of zero-starting torque. The existing BL topologies use expensive rare-earth permanent magnets (RE-PMs) to improve the starting torque; however, the marker price of RE-PMs fluctuates. Therefore, this paper proposes the use of the reluctance torque for improving the starting and average torques of BL-WFSMs. The winding topology and machine layout are adopted, from recently published work. The suggested approach increases the reluctance effect in BL-WFSM by optimizing the rotor shape. The reluctance effect is optimized, to improve the starting and average torques. The Kriging method and a genetic algorithm are used for the rotor optimization. A two-dimensional finite element analysis confirms the improved starting and average torques based on the increase in the reluctance torque. [ABSTRACT FROM AUTHOR]

This paper proposes a two-phase radial flux brushless DC motor comprising a rotor decorated with hybrid permanent magnet (PM) material, i.e., rare-earth NdFeB magnets combined with ferrite magnets. The rare-earth NdFeB magnets are used on the surface, and ferrite magnets in the spoke-type configuration. The combined surface and spoke-type topology are used to improve the output torque as well as to protect magnets of different grades against irreversible demagnetization. The motor is operated using the only-pull drive technique, which allows the use of thin magnets in the motor without the effect of irreversible demagnetization. The electromagnetic performance of the proposed motor is compared with those of a two-phase surface-type PM motor and the spoke-type motor, all driven by the only-pull drive technique. Furthermore, the operating point of the ferrite magnets is analyzed using finite element analysis to confirm the demagnetization endurance of the proposed motor. [ABSTRACT FROM AUTHOR]

This paper proposes an optimal design for a surface-mounted permanent magnet motor (SPMM) to reduce torque pulsations, including cogging torque and torque ripple, by using multi-grade ferrite magnets. Based on a conventional SPMM with single-grade ferrite magnets, the proposed SPMM is designed with four-grade ferrite magnets and then optimized to minimize torque pulsations by maintaining the required torque, utilizing the Kriging method and a genetic algorithm. The results obtained by the finite element analysis show that the optimized SPMM with multi-grade ferrite magnets exhibits improved airgap flux density distribution with highly reduced cogging torque and torque ripple by maintaining the same average torque, as compared to the conventional SPMM. Furthermore, the analysis of the working points for the multi-grade ferrite magnets reveals that the optimized SPMM has good durability against the irreversible demagnetization. [ABSTRACT FROM AUTHOR]

In this paper, a new consequent-pole hybrid excitation brushless wound field synchronous machine (CpHE-BL-WFSM) with fractional-slot concentrated winding is proposed. The proposed machine inherits the features of a brushless excited topology in which a rotor field is excited through an additional sub-harmonic magnetomotive force generated by the stator winding arrangement. In conventional BL-WFSMs, the zero starting torque and relatively low efficiency compared to that of permanent magnet synchronous machines (PMSMs) makes it difficult to replace expensive PMSMs in low- and medium-power applications. The advantages of the proposed machine are improved efficiency, improved starting torque, and high electromagnetic torque as compared to conventional brushless machines. A 2-D finite-element analysis is conducted to compare the proposed machine with the conventional BL-WFSM topologies. The results reveal that the proposed machine topology exhibits greater efficiency, improved starting torque, high average torque, and improved torque density. [ABSTRACT FROM AUTHOR]

In this paper, comparisons of the interior permanent magnet (IPM) BLDC motor characteristics considering the slot-pole combination and the magnetization direction simultaneously were done. The three directions of magnetization, radial, parallel and concentration were selected and analyzed for the same permanent magnet shape. No-load and load characteristics were compared. As a result, the motor efficiency of the combination of 6-slot and concentration directions was the best. Through analysis and comparisons, it was confirmed that the magnetization direction should also be considered as an important variable in initial design of the motor. [ABSTRACT FROM AUTHOR]

This paper presents a consequent pole changing vernier machine (CPCVM) for variable speed application such as electric vehicles. The proposed topology works as a 48-pole vernier machine with a consequent pole rotor in the low speed region. In this mode, the machine provides high torque and high efficiency. Also, the machine uses less amount of magnet volume than a surface permanent magnet machine. However, in high speed region, the poles of the machine are changed and the machine switches to permanent magnet synchronous machine (PMSM) mode that provides high efficiency in the high speed region. Therefore, the machine combines the advantages of a consequent pole vernier machine and a conventional PMSM in a single topology. The variable speed range of the machine is extended by pole changing operation. The merits of the proposed topology are investigated by finite element analysis and the feasibility of the machine is confirmed for variable speed operation. [ABSTRACT FROM AUTHOR]

This paper proposes a novel rotor strategy for the spoke-type IPM machine (STIPMM) with four surface-mounted ferrite magnets to increase torque density and decrease torque ripple. An asymmetrical rotor structure concept is used during the design process to increase the efficiency of the two torque compositions of the STIPMM, the reluctance torque and the magnetic torque. In this design, the torque is improved by ensuring that the maximum value points of the magnetic torque and the reluctance torque are closer to each other. In order to excavate the greatest potentiality of the initial model, the Kriging method and genetic algorithm are used to obtain the optimized model. To verify the analysis result, the frozen permeability method (FPM) is employed to provide feasible insights into the separation of the torque components based on a 2-D finite element method (FEM). To highlight the superiority of the initial model, a conventional STIPMM with symmetrical rotor structure is adopted for comparison under the same magnet amounts, machine size and operating conditions. [ABSTRACT FROM AUTHOR]

This paper proposes a variable-flux Vernier machine with dual consequent pole configuration to realize wide speed-range operation. The rotor has a consequent pole structure with high coercive force (HCF) material composed permanent magnets (PMs), whereas the stator has PMs positioned between the flux modulation poles. Stator-mounted PMs are made of low coercive force (LCF) materials that can be easily demagnetized or magnetized for variable-flux machines. By changing the magnetization state of the LCF PMs, suppression of magnetic flux was increased to reach higher-speed operation. Demagnetization of the stator LCF PMs reduced the total magnetic flux to reach a higher speed range. In addition, reverse magnetization allowed the machine to achieve further speed-range enhancement. The proposed machine was improved with a parametric selection process. Machine performance of each magnetization state was analyzed by way of speed torque curves and efficiency maps. [ABSTRACT FROM AUTHOR]

This paper presents a dual-rotor permanent magnet synchronous reluctance machine (PM-SynRM) with toroidal windings to improve the magnetic torque and the utilization of two torque components, thus to obtain high electromagnetic performance, such as torque, efficiency, and power factor. To highlight the advantages of the proposed dual-rotor PM-SynRM, all of its machine characteristics, including airgap flux density, back electromotive force (EMF), torque, power, efficiency, and flux weakening capability are compared to those of a conventional PM assisted SynRM (PMA-SynRM) with the same machine size and operating conditions, with the aid of a finite element method (FEM) using the JMAG-Designer. Furthermore, the proposed dual-rotor PM-SynRM is verified to have superior endurance against the magnet irreversible demagnetization within five times of the rated current excitation. [ABSTRACT FROM AUTHOR]

This paper presents the optimal design of a dual airgap spoke type permanent magnet vernier machine with dual stator dual winding (DDW) and dual stator single winding (DSW) models having an equal outer diameter and the same magnet volumes. The models were compared at a similar power and volume basis. Latin Hypercube Sampling and the Kriging Method is used to optimize the stator slots in DSW models for improved performance. 2D-Finite Element Method (FEM) was used to verify the results and compare the both models. The DSW model performs similar in terms of average torque, back EMF and shows a better performance regarding torque ripple, power factor and core loss as compared to DDW model having same dimensions on similar power and volume basis. Furthermore, DSW model has the advantage of having lesser manufacturing complexity and thermal issue posed by inner stator winding. [ABSTRACT FROM AUTHOR]

This paper proposes a novel hybrid-excited wound-rotor synchronous machine (HE-WRSM) with asymmetrically positioned permanent magnets (PMs) to make full use of reaction torque and reluctance torque, thus to improve the machine performance, including torque, efficiency, and power factor. To highlight the advantage of the proposed HE-WRSM, the conventional WRSM and HE-WRSM are adopted for performance comparison under the same operating conditions. All machine characteristics are predicted by the finite element method (FEM) using the commercial software, JMAG-Designer. The analysis results finally demonstrate that the proposed HE-WRSM exhibits highly improved torque, power factor, and efficiency, when compared to the conventional machines. Furthermore, the proposed HE-WRSM is verified to have superior endurance against the magnet irreversible demagnetization within two times of the rated current excitation. [ABSTRACT FROM AUTHOR]

This paper presents an optimal design for a surface-mounted permanent magnet (SPM) motor to suppress torque pulsations and save the magnet cost, by using multi-grade permanent magnets. Based on a conventional SPM motor with single-grade bonded NdFeB magnets, the proposed SPM motor is designed with two-grade bonded NdFeB and one-grade ferrite magnets, and then optimized by combining the Kriging method with a genetic algorithm, for further minimizing torque pulsations and saving the magnet cost by maintaining the high average torque. As a result, the cogging torque, torque ripple, and magnet cost of the optimized SPM motor are highly reduced compared to those of the conventional SPM motor. Furthermore, the optimized SPM motor is verified to have superior endurance against the magnet’s irreversible demagnetization within three times of the rated current excitation. All motor characteristics, including airgap flux density, cogging torque, electromagnetic torque, and demagnetization ratio are first predicted with the aid of a finite-element method. Finally, the optimal design and analysis results are validated by the experimental results. [ABSTRACT FROM AUTHOR]

This paper presents a novel consequent-pole hybrid brushless wound-rotor synchronous machine (CPH-BL-WRSM). The proposed machine employs permanent magnets (PMs) on the alternate poles of the salient pole rotor, which has considerably less magnet usage compared to the regular (PM) assisted synchronous machine. The proposed CPH-BL-WRSM offered the advantages of high starting torque, high torque density, and better performance under full-load conditions. The BL operation for the proposed machine is achieved by generating a composite magneto motive force (MMF) with a fundamental component and sub-harmonic component. The sub-harmonic component of the stator MMF is used for BL excitation of the rotor. The finite-element method was used to analyze the performance of the CPH-BL-WRSM in comparison with the performance of the existing BL-WRSM and regular PM-assisted BL-WRSM. Finally, a prototype of the CPH-BL-WRSM was manufactured and the experiment was conducted to demonstrate the performance of the proposed CPH-BL-WRSM. [ABSTRACT FROM AUTHOR]

In this paper, a design scheme for a novel energy-saving contactor using two-phase magnetic material is presented. A magnetization model using two-phase magnetic material was built with mathematical modeling and the theory of the Preisach model. The conversion mechanism was analyzed in order to reveal the relationship between the remanence and coercivity. The manufacturing process of the material is also described. Based on the differences between the transformation characteristics of the two-phase magnetic material in the permanent magnet and the soft magnetic field, an energy-saving contactor was designed by using two-phase magnetic material based on the remnant magnetism of 75 Oe. The simulation and experiment results show that the proposed energy-saving contactor functions well. [ABSTRACT FROM AUTHOR]

In this paper, a high force density, high-temperature superconductor dual-stator tubular Vernier machine (HTS-DSTVM) has been proposed for wave energy extraction. The machine adopts dual-stator configuration with spoke-type permanent magnets on the translator. The inner stator does not have any winding, and HTS bulks are placed between the adjacent flux modulation teeth of the inner stator to decrease the leakage flux and improve the force density. The HTS bulks effectively shield the leakage flux of the proposed HTS-DSTVM to improve the force density and power factor. 2-D finite-element method results validate that the proposed HTS-DSTVM yields a higher thrust force density per magnet volume and higher power factor compared with the recently presented flat dual-stator spoke-type linear Vernier machine due to the leakage flux shielding effect of HTS bulks. [ABSTRACT FROM AUTHOR]

This paper presents an advanced design procedure for stator-based and rotor-based permanent magnet (PM) machines to improve the electromagnetic performance by incorporating the spoke-type magnet configurations, phase-group concentrated coil windings, and an unaligned arrangement of two rotors/stators. The dual-rotor switched flux PM machine (SFPMM), designated as the stator-PM machine, and the dual-stator spoke-type interior PM machine (S-IPMM), termed the rotor-PM machine, are designed by the proposed design procedure to obtain high torque density and low pulsating torques for direct-drive applications. A quantitative comparison is performed between the proposed SFPMM and S-IPMM, and a conventional SFPMM with concentrated windings is adopted as the referenced model to evaluate the contribution of the proposed design procedure. The machine performance including back electromotive force, cogging torque, and electromagnetic torque is first analyzed by a finite element method under the same operating conditions. Finally, a prototype of the dual-stator S-IPMM is manufactured, and some key simulation results are verified by the experimental tests. [ABSTRACT FROM AUTHOR]

This paper presents the design and analysis of a novel permanent-magnet (PM)-assisted synchronous reluctance machine (PMA-SynRM) with axially integrated magnets for improving machine performance by using a finite-element method (FEM). The proposed PMA-SynRM features a simple structure with high performance by incorporating the advantages of a SynRM and a surface-mounted PM machine (SPMM). In particular, the rotor parts of the SynRM and SPMM are assembled to make the “ $q$ -axis” located 45° (elec.) from the $d$ -axis. Thus, the magnetic torque and reluctance torque of the proposed PMA-SynRM reach the maximum values at the same current phase angle, for efficient production of the total torque. To highlight the advantages of the proposed PMA-SynRM, a conventional PMA-SynRM is adopted for comparison under the same operating conditions. The FEM analysis results finally demonstrate that the proposed PMA-SynRM has a higher total torque and power factor, as well as greatly reduced torque ripple, when compared to the conventional PMA-SynRM with the same magnet amounts. In addition, the Mises stress analysis indicates that the configuration of the proposed PMA-SynRM exhibits the advantage of avoiding stress deterioration in the rotor ribs. [ABSTRACT FROM AUTHOR]

This paper presents the design, optimization, and prototyping of a transverse flux-type-switched reluctance generator (TFSRG) with an integrated rotor consisting of the main and permanent magnet (PM) auxiliary poles. In the initial model, an integrated rotor has a simple structure, consisting of one magnet core and a yoke bar. The yoke bar was radially laminated and inserted in the rotor yoke to minimize loss of the magnetic flux, which flows along the axial direction. We analyzed the cogging torque and back-EMF characteristics of the proposed TFSRG using the finite-element analyses (FEA). The cogging torque in the analysis results for the initial model of the proposed TFSRG was relatively high cogging. To reduce a cogging torque, both corners of the stator and PM auxiliary poles were optimized using a circular fillet shape. To satisfy a design condition, the design variables of a circular fillet shape were effectively determined using the optimization algorithm, and the initial and optimal models were compared with the analyzed results by a FEA for steady state and a dynamic performance simulation for transient state, respectively. To verify the analyzed results, an optimized prototype TFSRG was manufactured and measured. The measurement results were in good agreement with analysis results, and the output performance of the prototype was verified by the experiment set. [ABSTRACT FROM PUBLISHER]

Conventional permanent magnet (PM) motors operate in both magnetizing (pull) process and reversible demagnetizing (push) process on the recoil line of magnets. Therefore, thin-surface PMs may easily undergo a risk of demagnetization at the push process under certain fault conditions, which lead to deterioration of motor performance. Thus, thick magnets, whereas contributing the significantly high cost, are usually used to minimize this risk in the PM motors. In this paper, a novel operation technique, that involves only the pull process, has been proposed for a unique design of two-phase brushless DC motor to avoid the irreversible demagnetization of the magnets. The motor, operated only in the pull process, is kept away from the push process of the operation. Therefore, the motor sustains its initial magnetic operating point above the knee point during the normal operation as well as under the short circuit fault conditions. Finite-element analysis is performed to validate the concept of the proposed technique. [ABSTRACT FROM PUBLISHER]

This paper focuses on the design and the analysis of an ultrahigh speed axial-flux permanent magnet (AFPM) machine for an aerospace flywheel energy storage system. The superiority of the proposed AFPM machine is the material-efficient PM shape, which contributes to obtain a sinusoidal back electromotive force (back EMF) and, hence, reduces the torque pulsations of the machine such as torque ripple. The harmonics present in back EMF have a large influence on iron loss and torque pulsations, which are always unacceptable in the applications involving the speed as high as 1 000 000 r/min. Analytical modeling is first performed to determine the PM shape for the proposed models. Then, the advantages of the proposed models are verified by comparing with the basic model with the conventional ring-shaped PMs using the 3-D finite-element method. The results show that the proposed models have a nearly ideal sinusoidal back-EMF waveform that significantly reduces the torque ripples compared with the basic model. [ABSTRACT FROM AUTHOR]

This paper presents two types of novel dual-stator two-phase permanent magnet synchronous machines (PMSMs) equipped with an advanced phase-group concentrated-coil winding and a spoke-type PM array for direct-drive applications. The key advantage of the proposed two-phase PMSMs is its superior flux-focusing effects, which greatly enhance the torque, benefiting from the whole machine configuration. To highlight the advantages of the proposed two-phase PMSMs, one three-phase PMSM and one two-phase PMSM with the conventional stator and winding configurations are adopted for comparison. All relevant machine characteristics, including the air-gap flux density, back electromotive force, and electromagnetic torque, are predicted by a 2-D finite-element method. Finally, one of the proposed dual-stator two-phase PMSMs is optimized to minimize cogging torque and torque ripples using the Kriging method and a genetic algorithm. [ABSTRACT FROM AUTHOR]

This paper proposes an improved transverse flux type permanent magnet reluctance generator (TFPMRG) for the purpose of reducing the leakage flux and improving the back EMF. This improved TFPMRG has auxiliary rotor poles with permanent magnet (PM) added between the main rotor poles. The auxiliary rotor pole is effective to obtain high-back EMF voltage source under no-load condition and to increase the amplitude and region of the generated current under load condition. To obtain these desired performances, PMs are inserted into both ends of auxiliary rotor pole. The auxiliary rotor and main rotor poles works at the same instance under load condition. Characteristics of the improved TFPMG are analyzed using the finite element analysis and it is verified that the improved TFPMRG has an excellent performance. [ABSTRACT FROM AUTHOR]

This paper proposes a novel double-stator axial-flux spoke-type permanent magnet vernier machine, which has a high torque density feature as well as a high-power factor at low speed for direct-drive systems. The operation principle and basic design procedure of the proposed machine are presented and discussed. The 3-D finite element method (3-D-FEM) is utilized to analyze its magnetic field and transient output performance. Furthermore, the analytical method and a simplified 2-D-FEM are also developed for the machine basic design and performance evaluation, which can effectively reduce the modeling and simulation time of the 3-D-FEM and achieve an adequate accuracy. [ABSTRACT FROM AUTHOR]

This paper focuses on the design and analysis of a novel material-efficient permanent-magnet (PM) shape for surface-mounted PM (SPM) motors used in automotive actuators. Most of such applications require smooth torque with minimum pulsation for an accurate position control. The proposed PM shape is designed to be sinusoidal and symmetrical in the axial direction for minimizing the amount of rare earth magnets as well as for providing balanced axial electromagnetic force, which turns out to obtain better sinusoidal electromotive force, less cogging torque, and, consequently, smooth electromagnetic torque. The contribution of the novel PM shape to motor characteristics is first estimated by 3-D finite-element method, and all of the simulation results are compared with those of SPM motors with two conventional arched PM shapes: one previously reported sinusoidal PM shape and one step skewed PM shape. Finally, some finite-element analysis results are confirmed by experimental results. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel transverse flux type permanent magnet reluctance generator (TFPMRG), which contains a permanent magnet (PM) in its U-shaped salient stator pole. A U-shaped stator core is designed with the short flux path to reduce the mutual effect between phases. Moreover, the proposed TFPMRG shape is designed for using PM instead of an excitation circuit to provide the field excitation, which increases the output power and efficiency. Both the transverse flux type switched reluctance generator (TFSRG) and the TFPMRG are designed using 3-D finite-element analysis (FEA) and a torque equation called the D-2L method. Finally, the design results of the TFSRG and TFPMRG are confirmed with 3-D FEA. According to the results, the output power and efficiency of TFPMRG are higher than those of TFSRG. [ABSTRACT FROM AUTHOR]

This paper proposes the optimization of an anisotropic ferrite magnet shape and magnetization direction to maximize back-EMF of IPM BLDC motor. Firstly, four different models of general magnet shapes are selected, and then FEM analysis is carried out with four different magnetization directions for each of four models. The best magnet shape and magnetization direction from each model are selected as an initial model for optimization. Secondly, based on the initial model, optimization design for maximum back-EMF and minimum cogging torque and THD is performed. Finally, validity and superiority of the optimization design are confirmed by manufacturing the prototype motor and performing the experiment. [ABSTRACT FROM AUTHOR]

This paper attempts to design a direct driven axial flux permanent magnet synchronous generator (AFPMSG) with better accuracy considering magnetic flux leakages and fringing effect, using D^{2}L method. Design results of conventional and improved design processes are analyzed and compared using 3D finite element method (FEM). Single and multi-stack AFPMSG topologies are designed by using an improved design process. FEM structural analysis is utilized to improve power to weight ratio of three-stack AFPMSG. Finally characteristics of both single and three-stack AFPMSG topologies are analyzed and compared using 3D FEM analysis. [ABSTRACT FROM AUTHOR]

This paper proposes a novel concentrated flux interior permanent magnet (IPM) type brushless DC (BLDC) motor that replaces low-price ferrite magnets, which has similar characteristics as the conventional IPM type BLDC motor that uses expensive NdFeB magnets. To minimize the cogging torque which is a disadvantage of the proposed model, optimal designs of rotor and permanent magnet were performed. In optimal design process, the Kriging method based on the Latin hypercube sampling (LHS) and a genetic algorithm (GA) are applied due to suitability to non-linear data. Furthermore, to improve the average torque of the proposed model, the current excitation range was changed according to inductance. Through the optimal design process and the proper current excitation range, we show that the optimal model using low-price ferrite magnets has similar performance as the conventional IPM type BLDC motor using NdFeB magnets. [ABSTRACT FROM AUTHOR]

A novel coefficient modeling technique, using a coefficient estimation method, is introduced for a brushless DC (BLDC) motor with a skewed permanent magnet and overhang structure. To construct the novel coefficient, the 3-D FEM and a design of experiment (DOE) are utilized along with the moving least square method (MLSM). Also, to verify the accuracy of the novel coefficient modeling, the conventional coefficient modeling using LSM is constructed and compared. Then the novel coefficient is combined with an approximate model constructed by 2-D FEM for use with an optimal design algorithm. For the searching process to obtain an optimal point, the genetic algorithm (GA) is used. Three-dimensional FEM simulation is used to verify the accuracy of the novel coefficient for the optimal design. [ABSTRACT FROM AUTHOR]

This paper introduces the Halbach array and an optimal design process to effectively increase thrust force and decrease the yoke volume in electro-magnetic linear actuator for fatigue and durability test machine. The finite element method is used for dynamic response analysis of the thrust, velocity and displacement. In the optimal design process, sampling points are chosen by Latin hypercube sampling and from the results, an approximation modeling is made by Radial basis function and then the optimization results are obtained by a Genetic algorithm. The simulation results are verified by experimental results. Using the optimal design process enables the optimized electro-magnetic linear actuator to effectively increase the thrust force considering the weight of linear actuator. [ABSTRACT FROM AUTHOR]

This paper presents the design and optimization of a novel wound field synchronous machine topology, in which permanent magnets (PMs) are introduced into the rotor slot opening with segment configuration for high quality output torque performance. The rotor shape of the proposed PM-assisted wound field synchronous machine with segment configuration is optimized for maximizing the average output torque and decreasing torque ripple under constant PM volume and motor size. The segment configuration can be benefit to improve the reluctance torque. In addition, it is further clarified that the assisted-PM can help to increase the field torque by enlarging the magnetizing synchronous reactance (Xf), as well as increasing airgap flux density. An optimal method combining Kriging method and genetic algorithm is applied for rotor shape optimization of proposed PM-assisted wound field synchronous machine (PMa-WFSM). Then, the 2-D finite-element analysis results, with the aid of JMAG-Designer, are used to confirm the validity. It is determined that the average output torque is improved by 31.66%, and keeps lower torque ripple without decreasing efficiency, increasing PM volume and motor size compared with those of the basic model. Finally, irreversible demagnetization and mises stress analysis verifies the reliability of the novel topology. [ABSTRACT FROM AUTHOR]