Comparison Of Electromagnetic Performance Research Articles

Design and Analysis of Surface-Mounted Permanent-Magnet Field-Modulation Machine for Achieving High Power Factor

Along with the establishment of general air-gap field modulation theory, a new type of field-modulation machine has attracted increasing attention. However, the low power factor always plagued its popularization. This paper is to focus on the simplest structure surface-mounted permanent-magnet field-modulation (SMPMFM) machine, aiming at exploring the implementation of high power-factor design. The key is that the power factor calculation formula is derived parametrically, hence the originally vague causal relationship between the structural parameters and power factor become clear, guided by which the initial structure design for high power factor achievement is determined, meanwhile the power factor adjustment evaluation and the electromagnetic performance comparison with the help of finite element analysis (FEA) are conducted to verify the validity of the proposed power factor calculation formula. Finally, a feasible high-power-factor SMPMFM prototype is fabricated and the experimental testing is performed, which has a good agreement with the formular calculation and FEA results. Hence, the validity of the proposed analysis for achieving high power-factor design of field-modulation machines is verified.

Comparison of electromagnetic performance in MW class superconducting machines according to shielding and structures based on analytical method

This paper presents an analytical method for analyzing the electromagnetic performance of a superconducting (SC) machine according to the 10 MW shielding configuration and the presence or absence of an armature core. To establish the SC machine design process, an analytical method considers shielding conditions and armature core type is included. The presented analytical method derives the governing equations and general solutions for each region using Maxwell’s equations and electromagnetic field theory. Furthermore, it calculates the analytical solutions by applying appropriate boundary conditions. Additionally, the performance of actively and passively shielded, with the same size and shielding performance of SC machine is compared. The electromagnetic performance obtained through the analytical method is compared with finite element analysis to validate its accuracy. The accuracy of the presented analytical method can be utilized in various design analyzes, including initial design and optimal design.

Design Principle Considering Structural Mutual Effects of Double-Stator V-Shape-PM Vernier Machines for Electric Ship Propulsion

This paper proposes the design principle considering structural mutual effects of double-stator V-shape permanent-magnet (DS-V-PM) vernier machines for electric ship propulsion (ESP). Due to the flux concentration effect of the V-PM configuration, the double stators can be divided as a major and a minor stator, considering the different torque generation capability. Cooperation mutual effects between the double stators, V-PM arrangement and vernier machine topology are specifically included in the machine design principle exploration. To illustrate the design principle, first, a unified design principle is deduced, fit for general PM vernier machines. Then, a multi-step optimization strategy with auxiliary of sizing equations is presented, focusing on the parameter cooperation with flux modulation effect. Furthermore, through electromagnetic performance comparison, specific mutual effects of the DS configuration, DS angle shift, V-PMs and barrier structure are clearly summarized. Based on the DS machine design, the multi-mode operation for ESP system is introduced and analyzed. The normal/faulty cruise mode and charging mode are included to realize bi-directional operation. Prototype experiments are carried out for verification of the proposed machine design and operating strategy.

Design and Analysis of a New Dual-Stator Hybrid Magnet Flux Modulation Machine

This paper proposes a new dual-stator hybrid-magnet flux modulation machine (DS-FMHMM) for direct-drive applications, which employs NdFeB magnet excitation and Ferrite magnet excitation on the rotor and outer stator sides, respectively. With this design, the proposed DS-FMHMM can not only fully use the bidirectional flux modulation effect, but also effectively alleviate the magnetic saturation issue. The machine configuration is described, together with the operating principle. Then, the design parameters of DS-FMHMM are globally optimized for obtaining high torque quality, and the influence of magnet dimensions on torque is analyzed. To evaluate the merits of the proposed DS-FMHMM, the electromagnetic performances of machines under different magnet excitation sources are analyzed, and a comprehensive electromagnetic performance comparison of DS-FMHMM and two existing dual-stator flux modulation machines (DSFMMs) is developed.

Analysis of Stator-Slot and Rotor-Pole Combinations of Axial Modular-Flux Reversal Permanent Magnet Machine

This paper investigates the influence of stator-slot and rotor-pole combinations on torque performances in axial modular-flux reversal permanent magnet (AM-FRPM) machines. Based on the slot-conductor back-EMF star vector theory, the winding factors of all stator-slot and rotor-pole combinations are improved by adopting toroidal windings. In addition, based on a magnetomotive-force and permeance model, the candidates of stator-slot and rotor-pole combinations with higher torque capacity can be determined by analyzing the harmonic combinations between the PM and armature reaction field. Besides, the cogging torque is suppressed by selecting the corresponding angle between rotor modules for different stator- slot and rotor-pole combinations. Finally, an electromagnetic performance comparison between a conventional FRPM machine and three AM-FRPM machines candidates with attractive torque performances is conducted, and the experiments are constructed to verify the theoretical analysis.

Sizing, Modeling, and Performance Comparison of Squirrel-Cage Induction and Wound-Field Flux Switching Motors

In this study, the analytical design and electromagnetic performance comparison of a squirrel-cage induction motor (SCIM) and a wound-field flux switching motor (WFFSM) for high-speed brushless industrial motor drives is undertaken for the first time. The study uses analytical sizing techniques and finite element analysis (FEA) to model and predict the performance of both motors at a 7.5 kW output power. This study includes detailed equations and algorithms for sizing and modeling of both types of motors, as well as performance calculations that aid in motor selection, design optimization, and system integration. The main findings show that the SCIM has superior torque performance for starting and overload conditions, while the WFFSM offers advantages in power factor, efficiency over a wide operating range, and potential for higher peak power output. To this end, the WFFSM is capable of high-speed and high-efficiency operation while the SCIM is suitable for applications requiring variable speed operation. The validation study shows good agreement between analytical and FEA calculations for both motors. The results provide insights into the design and performance characteristics of both motors, enabling researchers to explore innovative approaches for improving their efficiency, reliability, and overall performance.

Design and Analysis of New Dual-Stator Flux Modulated Machines With Dual-PM Excitation

This article proposes new dual-stator flux modulated machines with dual-permanent magnet (PM) excitation (DS-FMDPMMs) for direct-drive applications. The proposed DS-FMDPMMs are characterized by employing consequent-pole (CP) PMs on both the stator and rotor sides. By using dual-layer CP PMs, the DS-FMDPMMs can perform the bidirectional flux modulation effect to enhance the torque capability. In addition, the merits of dual-stator structure, such as high space utilization, high torque density, and power factor are inherited in the proposed machines. The design principle of DS-FMDPMM is provided at first, and the formed three representative DS-FMDPMMs with different stator-PM arrangements are proposed. Then, the design considerations of three DS-FMDPMMs are described in detail, which includes the armature winding design, the selection of stator-slot/rotor-pole combination, and the influence of critical structural parameters on torque. In order to find an optimal direct-drive candidate among the three DS-FMDPMMs, a quantitative electromagnetic performance comparison is developed through finite element analysis (FEA). The results show that among the three machines, DS-FMDPMM-I accommodates the highest torque density, lowest torque ripple, best over-load torque capability, and highest efficiency. Moreover, to further verify its performance advantages, the electromagnetic performances of DS-FMDPMM-I and two typical dual-stator flux modulated PM machines are compared through FEA. Finally, a prototype of the optimal DS-FMDPMM is manufactured and tested to validate the effectiveness of FEA-predicted results.

Electromagnetic Performance of Waveguide Polarizers with Sizes Obtained by Single-Mode Technique and by Trust Region Optimization

Modern wireless networks, stationary terrestrial and satellite systems use many modern technologies to increase communication channels information capacity. They save limited frequency resources. In satellite communications the polarization signal processing is applied to reuse the allocated frequency bands. Usage of circularly polarized electromagnetic waves, which transmit useful signals, reduces fading effects and eliminates disadvantages introduced by multipath propagation interferences. In this case the distortion levels for signals with an odd number of electromagnetic waves reflections in the receiving antenna systems will be reduced down to the thresholds of their cross-polarization isolation. Besides, in the case of orthogonal polarizations usage, the achieved information capacity of the applied wireless communication channel multiples almost by the factor of two. The type of polarization of the used electromagnetic wave strongly determinates the peculiarities of the process of its propagation in the space or transmission line. Polarization signal processing is frequently carried out in horn feed systems of the reflector antennas. Such feed networks and systems allow to transmit and receive signals with several kinds of polarization at the same time. The fundamental element of dual circular polarization antenna feed networks is a waveguide polarization duplexer. The phase, isolation and matching characteristics of a polarization converter strongly influence on the functionality and polarization discrimination possibilities of the entire reflector antenna system. Therefore, the development and optimization of the characteristics of waveguide polarizers for satellite communication antennas is a crucial technical problem, which must be solved by fast and accurate methods. The comparison of electromagnetic performance of waveguide polarizers with sizes obtained using a fast single-mode technique and by more accurate trust region optimization method is carried out in this research. The results for differential phase shift, level of voltage standing wave ratio, ellipticity coefficient and cross-polarization discrimination are shown and discussed.

Novel Flux-Switching Machine With Star-Array Permanent-Magnet Arrangement

This article presents a novel flux-switching (FS) machine adopting star-array permanent-magnets (PMs), termed as star-FSPM machine. In comparison with the conventional spoke-FSPM machine, the proposed one can achieve not only enhanced flux-concentration effect, but also enlarged stator-slot area, thus improving PM utilization ratio and torque density. The harmonic characteristics of both PM field and armature reaction field in the star-FSPM machine are investigated based on the field modulation theory. More importantly, the torque generation mechanism of the star-FSPM machine is also investigated and compared with that of the spoke-FSPM machine. The results show that the proposed machine can utilize the working harmonics more effectively for torque generation. Afterwards, the electromagnetic performance comparison of four PM machines is carried out by finite-element analysis. It is found that the proposed star-FSPM machine exhibits improved PM utilization ratio and enhanced torque density as compared to the spoke-FSPM machine. Finally, the theoretical analysis and FEA results are verified by experimental measurement.

Comparison of Electromagnetic Performance according to Winding Configuration for Modular Dual 3-Phase Permanent Magnet Machines

A new winding structure for modular dual 3-phase permanent magnet machine, which makes it possible to reduce mutual coupling between two-winding sets of inverters and interference between phases that belong to the same inverter has been proposed in this study. The modular dual 3-phase system with overlapping winding technique has been widely employed in large-scale machine applications such as wind power production; however, its drawbacks include large torque ripple, long end-winding, and large magnetic mutual interference. To address these problems, a new modular dual 3-phase winding can be achieved by replacing adjacent redundant coils in one of the same phase coils with nonoverlapping winding. For clarity, three dual 3-phase machines are selected to examine their differences. The first is 32-poles/96-slots adopting a conventional overlapping modular winding (

Research on Electromagnetic and Structural Characteristics of Canned Electric‐Actuated Valve Permanent Magnet Synchronous Motor under Eccentricity

The high‐temperature canned electric‐actuated valve permanent magnet synchronous motor (CEAV‐PMSM) directly drives the valve load, which is prone to eccentricity operation, causing greater system vibration and shortening the valve operating life. In order to analyze the electromagnetic and structural characteristics of CEAV‐PMSM under different eccentricity faults, this paper uses analytical methods to derive the magnetic field distribution of the motor under normal and eccentricity conditions. Then, the Maxwell Stress Tensor method is used to derive the expression of the radial electromagnetic force under normal and eccentricity conditions, and the order of space–time harmonics that have a greater impact on CEAV‐PMSM are summarized. After that, the electromagnetic performance comparison of the three pole‐slot combinations under different eccentricity conditions, and the harmonic orders during eccentricity is analyzed by Fourier transform to obtain the optimal pole‐slot combination, which verified the correctness of the analytical calculations. In addition, the influence of different eccentricity conditions on the radial force density and unbalanced magnetic pull are studied. On this basis, the vibration response of the motor under eccentricity is analyzed, and the influence of the canned sleeve on the vibration performance of the motor is discussed. Finally, the modal analysis of CEAV‐PMSM is carried out to prevent the occurrence of resonance under eccentricity, which provides some references for reducing the vibration and noise of the canned electric‐actuated valve. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Design, Analysis, and Optimization of Permanent Magnet Vernier Machines Considering Rotor Losses

The purpose of this paper is the design, analysis, and optimization of a new structure of a permanent magnet vernier machine (PMVM) with a high torque density and low rotor losses. First, the modulation principle and topology of this PMVM is introduced. Then, its average torque and rotor loss are enhanced and reduced by optimizing the flux modulation poles distribution. For the sake of further reducing the rotor losses on the premise of maintaining the torque density, the contribution of the air gap flux density harmonics to the rotor loss is analyzed. Then, a new topological structure of a rotor with a flux barrier is introduced to reduce the rotor losses due to the decrease of each harmful harmonic. Through the analysis of the structure of the PMVM with the flux barrier, the influence of the parameters on the performance is built. After that, a multi-objective optimization algorithm is used to optimize the PMVM so as to obtain the optimal performance. Moreover, the electromagnetic performance comparison between the newly proposed machine and the original one is presented to indicate that lower rotor losses can be obtained by the proposed machine when the torque is ensured. Finally, a prototype of proposed PMVM is built and further tested to verify the validities of the theoretical and finite-element analyses.

A Novel Asymmetric Rotor Interior Permanent Magnet Machine With Hybrid-Layer Permanent Magnets

This article proposes a novel asymmetric interior permanent magnet (AIPM) rotor topology for torque enhancement and torque ripple reduction in IPM synchronous machines. The AIPM rotor structure is featured by a hybrid-layer permanent magnet configuration, i.e., for each pole, a part of PM configuration has one-layer while the other part has two layers. It allows the magnetic-field-shifting (MFS) effect to be utilized by reducing the current angle difference between maximum PM and reluctance torque components, thereby effectively increasing the maximum resultant torque. The proposed AIPM machine and a conventional V-shape IPM machine are designed and globally parametric optimized with the same 24-slot/4-pole stator, rotor diameter, and PM usage. The influence of key rotor geometric parameters of the AIPM machine on torque and open-circuit air-gap magnetic field characteristics are investigated. The comparison of electromagnetic performance confirms that significant torque enhancement and torque ripple reduction in the AIPM machine compared with the conventional V-shape IPM machine and reveals the MFS effect is essential for torque increase. Finally, an AIPM machine is manufactured and tested for validation.

Multi-objective optimization of high torque density segmented PM consequent pole flux switching machine with flux bridge

Due to double salient structure, Flux Switching Machines (FSMs) are preferred for brushless AC high speed applications. Permanent Magnet (PM) FSMs (PM-FSMs) are suited applicants where high torque density (T den ) and power density (P den ) are the utmost requisite. However conventional PM-FSMs utilizes excessive rare earth PM volume V PM , higher cogging torque T cog , high torque ripples (T rip ) and comparatively lower (T den ) and P den due to flux leakage. To overcome the aforesaid demerits, a new high (T den ) Segmented PM Consequent Pole (CP) FSM (SPMCPFSM) with flux bridge and barrier is proposed which successfully reduces V PM by 46.52% and PM cost by 46.48%. Moreover, Multi-Objective Optimization (MOO) examines electromagnetic performance due to variation in geometric parameters for global optimum parameters with key metric such as flux linkage (Φ pp ), flux harmonics (Φ THD ) average torque (T avg ), T cog , T rip , T den , average power (P avg ) and P den . Analysis reveals that MOO improve Φ pp by 22.68%, boost T avg by 11.41%, enhanced P avg by 4.55% and increased T den and P den by 11.41%. Detailed electromagnetic performance comparison with existing state of the art shows that proposed SPMCPFSM offer T avg maximum up to 88.8%, truncate T rip up to 24.8%, suppress T cog up to 22.74%, and results 2.45 times T den and P den .

A systematic design optimization approach for interior permanent magnet machines equipped with novel semi-overlapping windings

In this paper, a systematic approach to achieve optimized design of interior permanent magnet machine (IPM) having novel semi-overlapping windings (NSWs) is presented. The optimization parameters have been determined individually by performing sensitivity analyses. Multi-objective global optimization is subsequently performed. Genetic algorithm (GA) approach, which is also known as “random search with learning algorithm” and an effective optimization tool used for design optimization of electric machines, is employed. IPMs equipped with integer-slot distributed winding (ISDW) and NSW are initially designed by using the geometric and operating parameters of Toyota Prius 2010 IPM. Subsequently, a time-stepping 2D finite element analysis (FEA)-based program is employed to perform the optimization and quickly evaluate the optimal solution among the thousands of design candidates thanks to the sensitivity analyses. In order to reveal the effectiveness and rapidity of the multi-objective global optimization, a comprehensive electromagnetic performance comparison between the original (with ISDWs), initial and optimal designs (with NSWs) is presented. Finally, a small IPM prototype globally optimized by using the proposed procedure is manufactured, and the FEA results have been validated by measurements. Our goals in this study is to advance the state of the art in the multi-objective design optimization of NSW IPMs by performing sensitivity analyses to reach the optimal solution quickly and to determine the most sensitive design parameters affecting the key performance characteristics.

Investigation of influence the slot/pole combinations on the torque performance for synchronous reluctance machine with distributed and concentrated windings

This paper explores the electromagnetic performance comparison of three different types of synchronous reluctance machines. The investigated machines including, conventional full pitch distributed winding (24 slots/4 poles), an integer slot concentrated nonoverlapping winding (12 slots/4 poles), and fractional slot concentrated nonoverlapping winding (15 slots/8 poles). A finite element analysis JMAG Designer is used to validate the performance for all machines, and have been employed for the optimisation process to improve the torque density as well as to minimise torque ripple. Meanwhile, the current density, slot filling factor and specific dimensions, viz., stator outer diameter, stack length and air gap are designed to be constant. The result shows that for a DW-SynRM, a high value of average torque is achieved, and the torque ripple is lower. The result also demonstrates that the FSCW-SynRM can reach a low torque oscillation. Meanwhile, the ISCW-SynRM exhibit a high reluctance torque, but the torque ripple is a big challenge. On the whole, the distributed winding machine has the best performance compared to concentrated winding machines.

Comparative study on performance characteristics of PM and reluctance machines equipped with overlapping, semi‐overlapping, and non‐overlapping windings

In this study, the compatibleness/effectiveness of the proposed novel semi-overlapping winding (NSW) topology has been investigated by implementing into different synchronous machine technologies, namely interior permanent-magnet machine, synchronous reluctance machine (SynRM), permanent-magnet assisted SynRM, and double-salient reluctance machine. All considered machines have also been designed with different winding topologies; i.e. integer-slot distributed winding, fractional-slot concentrated winding (FSCW) in order to reveal the merits/demerits of the proposed NSWs. A comprehensive electromagnetic performance comparison has been presented. It has been validated that the proposed winding topology promises significant advantages; such as improved efficiency with substantially reduced total axial length, low eddy permanent magnet (PM) loss and low risk of irreversible magnet demagnetisation over conventional winding topologies. It has also been revealed that the implementation of proposed NSWs into the reluctance machines results with higher torque and power output than that of FSCWs.

Comparison of Electromagnetic Performance of SCPM Wind Power Generators With Different Topologies

This paper focuses on the comparison of electromagnetic performance of the superconducting permanent magnet (SCPM) generators with two different topologies. The torque capabilities of the two generators are first investigated. The peak torque is largely restricted by the material characteristics of the superconducting (SC) and the permanent magnet. The SCPM generators with iron-cored rotor and iron-cored stator topology (IRIST) is superior to the one with iron-cored rotor and air-cored stator topology in terms of torque capability. Furthermore, the flux density, line electromotive force, torque and its torque ripple, and the efficiency of the designed generators are evaluated by using numerical model. The simulation results confirm that IRIST has higher output torque and efficiency with the penalty of higher harmonics and torque ripples.

Quantitative comparison of electromagnetic performance of electrical machines for HEVs/EVs

In this paper, various types of sinusoidal-fed electrical machines, i.e. induction machines (IMs), permanent magnet (PM) machines, synchronous reluctance machines, variable flux machines, wound field machines, are comprehensively reviewed in terms of basic features, merits and demerits, and compared for HEV/EV traction applications. Their latest developments are highlighted while their electromagnetic performance are quantitatively compared based on the same specification as the Prius 2010 interior PM (IPM) machine, including the torque/power-speed characteristics, power factor, efficiency map, and drive cycle based overall efficiency. It is found that PM-assisted synchronous reluctance machines are the most promising alternatives to IPM machines with lower cost and potentially higher overall efficiency. Although IMs are cheaper and have better overload capability, they exhibit lower efficiency and power factor. Other electrical machines, such as synchronous reluctance machines, wound field machines, as well as many other newly developed machines, are currently less attractive due to lower torque density and efficiency.

Novel 6/7 Stator/Rotor Hybrid Excitation Doubly Salient Permanent Magnet Machine

One novel 6/7 stator/rotor hybrid excitation-biased flux permanent magnet machine (HE-BFPMM) is proposed in this paper. First, it discusses the new structure and operation principle in detail. Then, one improved design optimization technique is proposed to refine the HE-BFPMM based on a 2-D finite-element algorithm. Afterward, a comprehensive electromagnetic performance comparison between HE-BFPMM and original 6/7 stator/rotor BFPMM (ORI-BFPMM) has been made quantitatively by the premise of constant out radius and axial length. It indicates that, compared with ORI-BFPMM, the HE-BFPMM can demonstrate much higher no-load back electromotive force, lower torque ripple, higher PM material utilization ratio, and stronger flux-weakening capability.