Flux-switching Permanent Magnet Motor Research Articles

Sürekli mıknatıslı akı anahtarlamalı motorda mıknatıs, stator ve rotor geometrilerinin tork ve tork dalgalanmasına etkisinin incelenmesi

Bu çalışmada, referans alınan bir sürekli mıknatıslı akı anahtarlamalı motora (SMAAM) ait mıknatıs geometrisi ve konumu ile stator ve rotor çıkıntılarında değişiklikler yapılarak yeni tasarımlar gerçekleştirilmiştir. Referans tasarım olarak daha önce literatüre sunulmuş olan üç fazlı bir SMAAM temel alınmış ve tüm motor yapılarına ait benzetim çalışmaları yapılmıştır. Adil bir kıyaslama yapılabilmesi için benzetim çalışmalarında tüm SMAAM tasarımlarında temel parametre ve kullanılan malzemeler korunmuştur. Yapılan tasarımsal değişiklikler ile kabul edilebilir tork değeri beraberinde düşük tork dalgalanması, üretim kolaylığı ve geniş hız aralığında çalışma yeterliliği elde edilmeye çalışılmıştır. Analiz çalışmaları, elektrik makinalarının analizinde yaygın bir şekilde kullanılmakta olan ve oldukça doğru sonuçlar verebilen sonlu elemanlar yöntemi (SEY) temel alınarak gerçekleştirilmiştir. Referans alınmış olan ve tasarlanan yeni SMAAM yapılarına ait elde edilen sonuçlar kapsamlı bir şekilde karşılaştırılmıştır. Bu karşılaştırmlar da tork değerinde kabul edilebilir azalmalar görülürken tork dalgalanma değerinde ciddi azalmalar olduğu sonucuna varılmıştır.

SSO-DRSS Axial Flux sensing in Switching Permanent Magnet Motor for cogging torque mitigation

This paper addresses the imperative requirements of high efficiency, power density, and speed in Axial Flux-Switching Permanent Magnet Motors (AxFSPM) for electric vehicles. Recognizing the limitations of conventional motor designs, especially their weight and size, hindering their universal applicability, this study proposes a novel approach. A Double Rotor Single Stator (DRSS) configuration is introduced, and its parameters are systematically optimized using the Shark Smell Optimization (SSO) algorithm. The SSO algorithm refines critical motor parameters, including axial length, turns per phase, and stator and rotor dimensions, resulting in a more compact AxFSPM motor with enhanced torque. Geometrical constraints are similarly optimized with SSO, and magnet skewing angles are employed for cogging torque reduction. The optimization process, implemented in MATLAB and ANSYS Maxwell, yields an average torque below 1.4 N m and cogging torque below 0.8 N m, demonstrating the effectiveness of the proposed approach. Comparative analyses against various motor models underscore the superiority of the SSO-optimized DRSS motor in terms of efficiency and compactness.

Multiple-Mode Current Control for a Hybrid-Excitation Axial Flux Switching Permanent Magnet Motor Considering Driving Cycles

This paper proposes a multiple mode current (MMC) control for hybrid-excitation axial flux switching permanent magnet (HE-AFSPM) motors considering driving cycles. To satisfy the diverse and compound control demands in multiple operating condition of EVs, the model predictive control is adopted, and multiple current vector prediction method including <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d</i> -axis current, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">q</i> -axis current, and DC excitation current is proposed to optimize current assignment ratio, enhance the dynamic performance, and improve motor efficiency. An online optimization method considering four operating conditions in two speed domains is demonstrated, where the different current assignment function and constraint is applied in each operating condition, and the optimal assignment currents are obtained effectively by the Lagrange multiplier method online in real time. Finally, to verify the feasibility of the multiple-mode control method, a prototype motor is built and tested. And, the motor performances in the different driving modes are investigated in detail. The experimental results reveal that the proposed control method can offer an effective control for the HE-AFSPM motor, where multi-mode operations are indispensable.

Design and Optimization of the Dual-Stator Axial-Field Flux-Switching Permanent Magnet Motor with High-Torque Density and Low-cost

Design and Optimization of the Dual-Stator Axial-Field Flux-Switching Permanent Magnet Motor with High-Torque Density and Low-cost

Design and Optimization of a Pole Changing Flux Switching Permanent Magnet Motor

A flux switching permanent magnet (FSPM) motor is designed and optimized in this paper to achieve high torque density and expanded speed regulation range from a design viewpoint of pole-changing (PC). Based on the field modulation theory, the PM field in the FSPM motor is modulated by the stator and rotor teeth, generating rich harmonics with different pole-pair numbers in the air-gap flux density. By adopting an appropriate slot pole combination, working harmonics with different slot pitch angles are obtained to establish a basis of the PC-FSPM motor. Then, different working harmonics can be used to achieve different energy conversions with different winding configurations, so the PC operation can be performed to realize the high torque and wide speed regulation range by switching the working modes. Based on the field modulation theory, the operation principle of conventional and PC-FSPM motors are analyzed and compared. Then, according to the design principle of the PC-FSPM motor, a 24/22-pole PC-FSPM motor with the E-core is designed and optimized by a multi-level optimization method. Finally, the electromagnetic performances are analyzed by finite element analysis and the test results of the prototype have verified the feasibility of the motor.

Design of 6 slots/10 poles modular rotor sandwich switched flux switching permanent magnet motor

Conventional flux-switching permanent magnet brushless machines (PMFSM) gained a lot of attraction due to their high torque densities, simple and robust rotor structure, and the permanent magnets and coils on the stator. The sandwich PMFSM machine has been proposed to improve the torque density of the machine in which two PM pieces are sandwiched in one stator pole to enhance the PMs usage efficiency. 2D finite element analysis (2DFEA) method is employed to compare the performance of sandwich PMFSM with salient rotor topology with that of sandwich PMFSM with modular rotor, in terms of flux linkage, flux distribution, flux strengthening, induced back EMF, cogging torque and average torque. From the results it is shown that the salient sandwich PMFSM and sandwich PMFSM modular rotor produces 9.28Nm and 6.7Nm, respectively.

A Novel Fault Tolerance Structure of Arc Linear Flux Switching Permanent Magnet Motors Based on Redundant Winding

This paper presents a novel structure of the arc linear flux switching permanent magnet motor based on the redundant winding to inhibit the rises of the motor losses and temperature due to the open circuit fault tolerance. Firstly, the structural characteristic of the arc linear flux switching permanent magnet motor is introduced. Then, the fault tolerance current of single phase open circuit fault is calculated for different winding connection forms. The fault tolerance performances under different conditions are compared from a special view of motor temperature rises. Finally, a novel structure for fault tolerance enhancement is proposed, which can effectively improve the freedom degree of the fault tolerance current by using the redundant winding. This novel structure takes full advantage of the circumferential air gap between the arc stator. The calculation results show that the novel structure can allow the fault tolerance of open circuit fault has little influence on the motor copper losses and temperature rises while maintaining the on-load torque.

Suspension Flux Internal Model Control of Single-Winding Bearingless Flux-Switching Permanent Magnet Motor

A suspension flux internal model control method is proposed to address the problem of the strong coupling of a single-winding bearingless flux-switching permanent magnet motor leading to a significant ripple of the rotor radial displacement. Firstly, based on air-gap magnetic field modulation theory, the stator flux equation considering rotor dynamic eccentricity is established to reveal the relationship between the eccentric rotor and the magnetic field. Secondly, according to the dynamic characteristics of the motor and the variation law of the air-gap magnetic field, the suspension-plane flux is substituted into the rotor dynamic model, and the suspension flux-dynamics internal model and corresponding output are constructed, respectively. Finally, a complete control strategy is established, and the rotor is stably suspended by PWM control. The simulation and experimental results show that the proposed method has better steady-state and dynamic performance than traditional PID control, and the maximum radial displacement ripples of the rotor are reduced by 53% and 50% in steady-state and dynamic operation.

Radial Displacement Sensorless Control in Full Speed Range of Single-Winding Bearingless Flux-Switching Permanent Magnet Motor

It is a key to realizing stable suspension operation of bearingless motor that the rotor radial displacement information is acquired accurately. Sensor applications are sensitive to environments, limiting to scenarios, and increasing costs. Herein, a radial displacement sensorless control method in the full speed range for single-winding bearingless flux-switching permanent magnet motor is proposed. First, an eccentric modulation function is presented, and the flux linkage equation of each winding with rotor eccentricity is derived based on the air-gap magnetic field modulation theory. Therein, the phase inductance and flux are functions of the rotor displacement. Second, the bias-flux equations of the symmetric windings are deduced, and the rotor displacement observer of the medium-high speed is established based on the bias-flux amplitude. Due to flux information being difficult to extract at low speed, the high-frequency current signal is injected into the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d_T</i> -axis of the torque plane. The rotor displacement observer of the zero-low speed is established based on the high-frequency bias-induced EMF amplitude. Besides, a novel smooth switching process is designed. Finally, the observers are analyzed, and the radial displacement sensorless control strategy is built. The experimental results verified the validity of the proposed method.

Optimal design of a yoke-less axial flux switching PM motor based on multi-objective PSO

PurposeIn this paper, an improved multiobjective particle swarm optimization (PSO) algorithm is proposed to optimize a three-phase, 12-slot, 19-pole, yokeless axial-field flux-switching permanent magnet (YASA-AFFSPM) motor.Design/methodology/approachBased on the structural characteristics of the YASA-AFFSPM, a mathematical model is established to calculate the main size of the YASA-AFFSPM motor. The split ratio, stator axial length, sandwiching pole angle, rotor pole angle, PM arc and number of conductors per slot are selected as optimization variables. Also, the efficiency, power factor, cogging torque and average torque are considered as the optimization objectives. The objectives are optimized by combining the improved multiobjective PSO algorithm with electromagnetic calculation.FindingsBased on the proposed algorithm, the investigated motor is optimized. The on-load efficiency, power factor and average torque of the motor performance have increased by 0.87%, 3.13% and 10.39%, respectively. Moreover, the cogging torque and slot fill factor have undergone decreases of 8.57% and 3.34%, respectively. Finally, the effectiveness of the algorithm is verified using experiment results.Originality/valueSo far, no comprehensive report has been observed on the optimization of the YASA-AFFSPM motor using evolutionary algorithms and the study of the effect of the motor parameters. Therefore, in this paper, the authors decided to investigate the effect of YASA-AFFSPM motor parameters and improve motor performance with the improved PSO method.

Design and Performance Investigation of a Vehicle Drive System with a 12/10 Flux-Switching Permanent Magnet Motor

The performance of a drive system with a flux-switching permanent magnet (FSPM) motor was studied through tests on a commercial electric vehicle (CEV). A practical design and an optimization method for the FSPM motor were proposed for a light-duty CEV. The initial dimensions of the motor were calculated by theoretical equations referring to a permanent magnet synchronous motor. Then, optimization was conducted through a response surface methodology (RSM) and a genetic algorithm (GA) based on three-dimensional finite element analysis (3D-FEA). With the optimized parameters, a prototype of the FSPM drive system was manufactured and assembled into an actual CEV. The performance of the CEV was investigated on an automobile test platform. The experimental results show that the FSPM drive system could drive the CEV properly. The high-efficiency running time of the FSPM motor accounted for 84% of the total time tested, which shows great potential for practical application in CEVs. However, the experimental results also show that the FSPM motor faced problems of large speed deviation and high-temperature rise during the driving cycle test, which should be fully addressed for practical applications.

A New Fault-Tolerant Rotor Permanent Magnet Flux-Switching Motor

This article proposes a new fault-tolerant rotor permanent magnet flux-switching (FT-RPMFS) motor. The key of the proposed FT-RPMFS (PFT-RPMFS) motor is its new rotor topology with the unique configuration of the auxiliary PM (APM), located in the rotor to enhance the air-gap flux density. Besides, the PFT-RPMFS motor incorporates a union rotor structure, which makes it easy to be manufactured and strengthens its mechanical robustness when compared to the conventional FT-RPMFS (CFT-RPMFS) motor with a segregated rotor part, and therefore, the CFT-RPMFS motor is used as a benchmark to prove the performance of the PFT-RPMFS motor. For fair analysis and comparison, all the design parameter dimensions and materials are the same in both the CFT-RPMFS and the PFT-RPMFS motors with the same slot-pole synergy of 20-slot/11-pole. Furthermore, a multi-objective optimization technique is adopted to improve the output torque and reduce the torque ripple. Moreover, since the FT-RPMFS motor is evolved from a stator permanent magnet flux-switching (SPMFS) motor, the SPMFS motor is also selected as another benchmark to verify the superiority of the PFT-RPMFS motor. Finally, a prototype is manufactured and tested to verify the correctness of the theoretical analysis.

Broadening Design and Optimization of High-Efficiency Region for a Dual-Mechanical-Port Flux-Switching Permanent Magnet Motor

In this article, a dual-mechanical-port flux-switching permanent magnet (DMP-FSPM) motor is studied for achieving high-efficiency design and optimization. The key of this study is to propose an optimization design approach for broadening high-efficiency region, where the motor efficiency fitting curve and the speed–torque envelope curve are combined. First, the efficiency function is established according to the motor power and loss equation. Then, high-efficiency region boundary points are obtained by combination of the fitted efficiency curve and speed–torque envelope curve. Next, the efficiency of representative operating points is determined and optimized to realize the broadening of motor high-efficiency region. Finally, the effectiveness of the proposed method and the studied DMP-FSPM motor is verified by the study results and experiment test.

Active Disturbance Rejection and Ripple Suppression Control Strategy With Model Compensation of Single-Winding Bearingless Flux-Switching Permanent Magnet Motor

The speed and radial displacement of the rotor have the obvious ripples due to the strong coupling between torque and suspension force of a single-winding bearingless flux-switching permanent magnet motor, and the traditional PID/PI controller is difficult to suppress the disturbance of the unbalanced magnetic force. A linear active disturbance rejection control method based on model compensation is proposed in this article. First, the topology and operation principle of the motor are described, and then the dynamic model of the rotor and flux linkage model of the motor are analyzed. Accordingly, the integral-series standard mathematical models of the displacement and speed are deduced, and then the mathematical expressions of the controller gain and radial disturbance are obtained. Second, the linear extended state observer with known model perturbation information and the linear feedback control law are designed, and the parameters tuning method is given. Finally, the simulation and experimental results verified that the proposed method can significantly reduce the rotor displacement and torque ripples, and it has better disturbance rejection performance than the traditional PID/PI control method in the same stability margin.

Multi-Objective Design Optimization of a Hybrid Excitation Flux Switching Permanent Magnet Motor Based on Design Sensitivity Analysis

The hybrid excitation flux switching permanent magnet (HEFSPM) motor with magneticbridge is a topology of hybrid excitation flux-switching PM machines. Despite its excellent performancesuch as high torque/ power density, high flux enhancing/ weakening capability and so on, it has receivedless attention due to its complicated structure. Therefore, its optimal design and performance all need tobe further investigated. This paper presents an optimal design of a HEFSPM motor with magnetic bridge.At first, the machine structure and basic working principle are discussed briefly. Then, a design sensitivityanalysis for geometric optimization is carried out to improve the motor performance. This optimizedmotor is compared with initial design. Finally, a prototype of the optimized proposed motor is built andtested to validate the simulation results.

Comparative Analysis and Design of Partitioned Stator Hybrid Excitation Axial Flux Switching PM Motors for In-Wheel Traction Applications

A comparative study of new partitioned stator hybrid excitation axial flux switching permanent magnet (HEAFSPM) motors with different partitioned excitation stator topologies for in-wheel traction applications is presented in this paper. The realization approaches of the partitioned stator HEAFSPM motor are discussed, and the motor topology with windings and permanent magnets (PMs) separately setting on different stators is selected in view of the advantageous structure for thermal management. On this basis, two partitioned excitation stator topologies including C-type tooth core and T-type tooth core stator configuration are proposed, and the air-gap flux modulation and flux regulation principle of the motors are analyzed. In addition, the design method of the partitioned stator HEAFSPM motor considering the effect of hybrid excitation sources is provided, and the two motors with different tooth cores are designed respectively. Meanwhile, for a fair comparison, the multiple objectives optimization method coupled with the sensitivity analysis is employed to optimize the two motors. The electromagnetic performances, anti-demagnetization capability, and flux regulation performance of the two motors are all investigated in detail. Finally, two prototype motors are fabricated and tested. Both the theoretical analysis and experimental results verify the effectiveness and reasonability of the motor.

Suppression of Torque Ripple of a Flux-Switching Permanent Magnet Motor in Perspective of Flux-Modulation Principle

In this article, the suppression mechanism of torque ripple for the flux-switching permanent magnet (FSPM) motor is investigated. According to the flux modulation principle, the generation principle of torque harmonics is analyzed, which is generated by the interaction between the radial and tangential airgap harmonics. Based on the analysis, a method to suppress the torque ripple of the FSPM motor is proposed, where the airgap harmonics are newly applied to be the bridge to establish the relationship among torque ripple, torque harmonic components, and key design parameters. To confirm the effectiveness of the proposed method, an FSPM motor with the V-shape permanent magnet (VS-FSPM) motor is selected as the research example. The leading torque harmonics and leading airgap harmonics of the VS-FSPM motor are picked out effectively. Some key design parameters are selected according to the flux modulation principle to improve the leading airgap harmonics and reduce the corresponding torque ripple successively. Furthermore, the torque ripples of the initial and improved VS-FSPM motor are calculated and compared in detail. Finally, a prototype motor is built and tested. Both the theoretical analysis and experimental results verify the effectiveness of the proposed new method.

Modeling and Analysis of Dual-Winding Bearingless Flux-Switching Permanent Magnet Motor Considering Magnetic Saturation Based on Subdomain Model

Dual-winding bearingless flux-switching permanent magnet machine (BFSPMM) is composed of power winding and suspension winding. The permanent magnet and the power winding provide a biased air gap magnetic field, and the suspension winding generates an air gap modulation magnetic field. The structure of stator and rotor are double salient poles. This paper proposes a subdomain model for the on-load field prediction in dual-winding BFSPMM. In the developed model, the field domain is divided into seven types of subdomains, viz. rotor slot, internal air gap, stator slot, permanent magnet slot upper layer, permanent magnet slot lower layer, permanent magnet, and external air gap. The electromagnetic parameters of the motor are analyzed, including air gap flux density, flux linkage, back-EMF, suspension forces, and electromagnetic torque. Based on the principle of conservation of magnetomotive force, a distributed equivalent magnetic circuit model is proposed to compensate for the magnetic saturation. Finally, the analytical predictions are verified by finite-element analysis and prototype experiments.

A dynamic model for the investigation of twisting effect in long flux‐ switching PM motors in ESPs

Shaft twisting occurs along the length of electric motors rotors. The twisting depends on the shaft properties and the transmitted torque. In Electrical Submersible Pumps, due to the high ratio of length to the diameter of the motor and the high load torque, the twisting effect occurs significantly. Thus, when such a condition emerges for an electric motor, the electromagnetic torque is not uniformly produced along the motor length, since shaft twisting results in rotor position variation with respect to the stator. Therefore, the twisting and the produced electromagnetic torque of the motor are interdependent. It means that these two issues cannot be studied separately and a model must be proposed to consider them together so that the electromagnetic performance of the motor can be studied under such conditions. Despite the importance of modeling the twisting effect for the electric motor, this issue has never been investigated before. In this article, a novel dynamic model for the flux-switching permanent magnet motor is proposed by which the shaft twisting effect is simulated to study the motor performance. Eventually, the twisting effect during startup and steady-state are studied as well as the effect of shaft diameter and motor length on shaft twisting. To evaluate the model, it is compared with the verified steady-state model for the flux-switching permanent magnet motor with the twisted shaft obtained from another article, and also results obtained by finite element analysis.

Performance optimisation of a segmented outer rotor flux switching permanent magnet motor for direct drive washing machine application

Electrical machines are widely used in home appliances, the performance of which is mostly related to the quality function of the electrical machines. What has been used so far in home appliances brought with themselves a wide assortment of advantages and disadvantages. With the aim to overcome the drawbacks of the previously implemented electrical motors in washing machines, a new configuration of flux switching permanent magnet motor (FSPM) with the segmented outer rotor (SOR-FSPM) is proposed benefitting from a direct driven drum. To reduce the cogging torque as well as torque ripple and to improve the total harmonic distortion, cutting the stator in a way to lower overlapping between the rotor and stator pole, inserting notches into the poles of the rotor to modify the air gap between the stator teeth and the rotor segments are proposed. The Taguchi method and sensitivity analysis are further applied to find the best combination set of changes in such a way to smoothen the chart showing reluctance between stator and rotor and fix the zero-point crossing of the flux linkages in different rotor positions. Finally, the proposed SOR-FSPM is prototyped, and experimental results along with the finite element method results are discussed and compared in order to verify the design process.