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In this paper, counter rotating dual rotor wound field flux switching wind power generator is revisited to study the generating characteristics of the AC output power curves based on finite element analysis (FEA) and experimental study. Analysis are performed under dynamic conditions, such as variable resistance, field excitation and speed. Also, electromagnetic performance is studied under variation of the field and armature currents. Analysis reveals that outer port machines with higher power capability and better electromagnetic performance compared to the inner port counterparts, although with higher fluctuations exhibited on the torque profiles of the former due to higher slotting effects. From the power generation characteristics curves, it is clear that the developed wind generator is able to produce reliable performance over a wide operating range. The accuracy of the FEA predicted results are validated, experimentally. The cover image is based on the Research Article Generating characteristics and experimentation of counter rotating dual rotor wound field flux switching wind generator by Wasiq Ullah et al., https://doi.org/10.1049/elp2.12374. [ABSTRACT FROM AUTHOR]

In this study, the focus is on the magnetic path formation and its effects on the performance of a counter-rotating dual-rotor permanent-magnet flux-switching machine (CR-DRPMFSM) for direct-drive counter-rotating wind power generation, based on different stator slot and rotor pole combinations. To fully exploit rotor-shaft bore and improve fault-tolerant design, as well as increase torque density, dual-rotor topologies with the capability for dual electrical and dual mechanical ports are investigated. Moreover, the direct-drive counter-rotating wind power generation technique offers a brushless topology, thus reducing maintenance cost and improving energy conversion efficiency compared to single-blade wind turbine systems. Using finite element analysis (FEA), the inherent magnetic coupling of the series and parallel paths shows varied impacts on the electromagnetic performance of four different CR-DRPMFSMs based on the slot/pole combinations (MI to MIV) considered in this study. The key electromagnetic performance indices, such as torque, cogging torque, torque ripple, power factor, and efficiency, show proportionate variation to the coupling level. A comparative analysis shows that MI exhibits higher average torque, lower torque ripples, and high efficiency, reaching 90% with a power factor of 0.6. As an optimal design, an MI test prototype is developed. The experimental test prototype validates the FEA results under no-load and on-load conditions. [ABSTRACT FROM AUTHOR]

In this paper, a novel low‐cost dual port dual rotor‐field excited flux switching generator (DPDR‐FEFSG) is proposed for low power rooftop wind turbine integrated with DC‐micro‐grids. The proposed DPDR‐FEFSG incorporated inner/outer machine to design a dual rotor structure with dual output port. Due to the existence of field excitation in DPDR‐FEFSG, overall machine cost is reduced and offered excellent flux regulation capabilities. Furthermore, single tooth non‐overlapped armature winding and toroidally wounded field winding significantly shorten end winding that reduces copper losses. Additionally, compared with the existing single‐bus DC‐micro grids system, the proposed DPDR‐FEFSG exhibits two‐port output which makes it feasible for low‐voltage (12–24 V) and high‐voltage (48 V) applications connected to the DC micro‐grids without the requirements of extra power electronics circuitry. The proposed DPDR‐FEFSG is investigated under variable field excitation and variable rotor speed. In order to achieve the desired voltage level at low and high port without frequency variation, AC–DC rectification is employed. Analysis reveals that proposed DPDR‐FEFSG offers dual output port from inner and outer machines. This dual port makes it feasible for wind turbine integrated to multi‐port DC micro‐grids. Due to availability of different voltages at various ports, different load classes are incorporated without the requirements of extra power electronics circuitry and thus reduce overall cost. Finally, a prototype is built and tested to confirm the validity of the proposed concept and finite element analysis (FEA) results. [ABSTRACT FROM AUTHOR]

Slotting effect in electric machines reduces flux per pole that effect magnetic flux density distribution in the air gap which induces harmonics in magnetic flux density causing flux pulsation, that in turn generates dominant torque pulsation in the form of cogging torque and torque ripples. To overcome the abovesaid demerits, a novel outer rotor field-excited flux-switching machine (OR-FSFSM) with a combined semi-closed and open slots stator is proposed in this study. The developed OR-FEFSM offers a high-power factor, due to the utilization of the semi-closed slot for armature coils. The open slot stator structure was chosen for the field excitation coil, which effectively suppresses leakage reluctance that causes flux pulsation. Thus, the influence of torque ripples is reduced, and the average torque is improved. In order to investigate the effectiveness of the proposed OR-FEFSM, a detailed study of stator slot and rotor pole combinations are performed. Based on simplified mathematical formulation, 12S/7P (stator slot/rotor poles), 12S/11P, 12S/13P, and 12S/17P are the most feasible combinations. Finite Element Analysis (FEA) based on comprehensive electromagnetic performance is performed on each combination, and found that 12S/13P offers the highest average torque of 4.62 Nm, whereas 3.72 Nm, 2.72Nm, and 1.68 Nm average torque is offered by 12S/17P, 12S/7P, and 12S/11P, respectively. Based on the initial analysis, 12S/13P was considered for further analysis and optimized using JMAG built-in Genetic Algorithm (GA). Moreover, thermal analysis was performed, and the proposed design was compared with the conventional design. [ABSTRACT FROM AUTHOR]

A Linear Oscillating Actuator (LOA) generates bi‐directional electromagnetic (EM) force between two extreme points. A new topology of moving magnet LOA with axial magnetised PMs and a C‐shaped stator core is proposed. On each side of the mover, two chamfered tubular‐shaped core material parts are attached. All the design parameters, such as mover mass and EM force of the LOA, are optimised using parametric analysis via parametric sweep, and the optimum values of the parameters are chosen based on design and performance parameters. The LOA's performance is examined for various input loading values and at different oscillation region positions. For various values of time‐dependent supply, the EM force's oscillating nature is analysed. The effect of resonance analysis on input current, stroke to current ratio, and efficiency are discussed. The proposed LOA is compared to current LOA topologies in terms of design structure and performance parameters. The FEM results are validated using a special experimental setup. The proposed LOA produces feasible results for the compressor in a refrigeration system. [ABSTRACT FROM AUTHOR]

In this paper, a novel dual mechanical port dual rotor counter-rotating permanent magnet flux switching generator (DMPDRCR-PMFSG) for wind turbine applications is proposed. Power distribution between the inner and outer rotors of the proposed DMPDRCRPMFSG that contributes to the cumulative output power is investigated. The proposed DMPDRCR-PMFSG shares a stator connected back-to-back through flux bridge. The flux bridge physically isolates the armature winding of the inner and outer ports. Furthermore, the flux bridge provides a flux path to magnetic flux of the inner and outer ports that contributes to cumulative output power. Quantitative comparative analysis of the inner and outer ports illustrates that under static analysis 18.57% more flux, 23.95% highly induced back-EMF, 31.08% of enhanced average torque are obtained in the outer rotor at the cost of 64.01% and 22.7% increase in cogging and torque ripple ratio, respectively. Comparative analysis with a number of turns reveals that the outer port offers 41.17% higher output power and 7.09% improved efficiency at the cost of 42.52% increase in voltage regulation factor. Finally, coupled overload and over-speed analysis shows that despite a stable and low voltage drop ratio, the outer port offers 4.65% higher output voltage. Analysis shows that in the proposed DMPDRCR-PMFSG, the outer port has a dominant contribution to the cumulative power distribution. [ABSTRACT FROM AUTHOR]

Flux switching motors (FSMs) with conventional stator slots have a relatively low copper slot filling factor. In this article, a new octane modular stator with pentagon-shaped slot electrically excited FSM (EEFSM) that has a comparatively higher copper slot filling factor is analyzed analytically to reduce computational complexity, high computational time, and high drive storage. The analytical results of the proposed EEFSM are validated via the finite element method. Furthermore, the initial design is optimized to improve the electromagnetic performance, and finally the prototype is fabricated and tested experimentally. There is good agreement among the analytical, finite element analysis (FEA), and experimental results with variations of 3%–5%. The average torque of the optimized design has improved by 30%, cogging torque is suppressed by 36%, and torque ripples have reduced by 38%, which have improved the performance of EEFSM in terms of low acoustic noise, low vibration, and longer motor lifetime. The proposed octane modular stator can be easily unfolded for windings maintenance, coils placement, and motor transportation in case of large-size applications. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to investigate an alternative simplified analytical approach for the design of electric machines. Numerical-based finite element method (FEM) is a powerful tool for accurate modelling and electromagnetic performance analysis of electric machines. However, computational complexity, magnetic saturation, complex stator structure and time consumption compel researchers to adopt alternate analytical model for initial design of electric machine especially flux switching machines (FSMs). Design/methodology/approach: In this paper, simplified lumped parameter magnetic equivalent circuit (LPMEC) model is presented for newly developed segmented PM consequent pole flux switching machine (SPMCPFSM). LPMEC model accounts influence of all machine parts for quarter of machine which helps to reduce computational complexity, computational time and drive storage without affecting overall accuracy. Furthermore, inductance calculation is performed in the rotor and stator frame of reference for accurate estimation of the self-inductance, mutual inductance and dq-axis inductance profile using park transformation. Findings: The developed LPMEC model is validated with corresponding FEA using JMAG Commercial FEA Package v. 18.1 which shows good agreement with accuracy of ∼98.23%, and park transformation precisely estimates the inductance profile in rotor and stator frame of reference. Practical implications: The model is developed for high-speed brushless AC applications. Originality/value: The proposed SPMCPFSM enhance electromagnetic performance owing to partitioned PMs configuration which make it different than conventional designs. Moreover, the developed LPMEC model reduces computational time by solving quarter of machine. [ABSTRACT FROM AUTHOR]

Permanent Magnet Flux Switching Machines (PMFSMs) enclose unique features of permanent magnet (PM) synchronous machine, direct current machine, and switch reluctance machine therefore, applicable for high speed brushless AC applications. However, conventional PMFSMs exhibits demerits of high PM volume VPM, high torque ripples Trip, low average torque Tavg, lower torque density Tden, power density Pden and leakage flux. In this paper, a new topology of 12S‐13P and 6S‐13P E‐Core PM Consequent Pole Flux Switching Machines (PMCPFSM) with flux barrier and partitioned PM is proposed that eliminate leakage flux, enhanced flux modulation effects through flux barriers and reduces the PM volume up to 46.53%. Moreover, due to non‐linear behaviour of PM and complex stator structure alternate analytical sub‐domain model is utilized for initial design and Multi‐Variable Geometric Optimization (MVGO) is opted to investigate influence of design parameters on electromagnetic performances such as Tavg, Trip, Tden and Pden. Analysis and comparison with the existing 12S‐10P E‐Core PMFSM, 6S‐10P E‐Core PMFSM, 6S‐10P C‐Core PMFSM and 12S‐14P C‐Core PMCPFSM reveals that proposed 6S‐13P PMCPFSM produced Tavg higher up to 88.8%, suppress Trip maximum up to 14.72% and offer 2.45 times Tden and Pden capabilities, when compared with the aforesaid state of the art.[AQ ID=Q1] [ABSTRACT FROM AUTHOR]

For variable speed applications, flux controlling capability of electrically excited flux switching motors (EEFSMs) attract researchers' attention. However, low copper slot filling factor of the EEFSM with standard stator slot vitiates the electromagnetic performance and efficiency. This paper has proposed a new Octane Modular Stator (OMS) EEFSM model that has pentagonal stator slot and high copper slot filling factor. Copper slot filling factor is deliberated analytically for the proposed model and designs with standard stator slots, i.e., trapezoidal and rectangular. Electromagnetic performance of the OMS, Rectangular Stator Slot (RSS) and Trapezoidal Stator Slot (TSS) EEFSM designs are evaluated by finite element analysis (FEA) through JMAG v18.1 FEA solver. The proposed OMS EEFSM model has 9% higher copper slot filling factor in comparison with standard stator slots designs under same geometric parameters. The high copper slot filling factor of the proposed OMS EEFSM model has improved performance in term of low electric and magnetic loading. [ABSTRACT FROM AUTHOR]

Flux switching machines (FSMs) encompass unique features of conventional direct current machine, permanent magnet (PM) synchronous machine and switch reluctance machine. Permanent magnet FSM (PMFSM) is capable of high torque density and applicable for high‐speed application, however conventional PMFSM exhibits demerits of high PM volume, high torque ripples and significant stator flux leakage. In this paper, a novel consequent pole E‐core stator PMFSM is proposed and compared with conventional topology utilising 2D finite‐element analysis (2D‐FEA). Finite‐element analysis revealed that proposed design enhanced flux modulation effects by introducing flux bridges and flux barriers as a result reduced cogging torque by reducing 46.53% of the total PM volume, reduce torque ripples by reducing PM slot effects and reduce flux leakage utilising flux bridges in the stator. Furthermore, analytical model for flux linkages, cogging torque, mechanical torque, no load and on‐load magnetic flux density (MFD) is developed for initial design of conventional and proposed model. 2D analytical methodologies resolve equivalent magnetic circuits for open‐circuit flux linkages, Fourier analysis for cogging torque, Laplace equations for MFD and Maxwell stress tensor for mechanical torque. Finally, results obtained from 2D‐FEA and analytical methodologies are validated and compared. [ABSTRACT FROM AUTHOR]

In this paper, two variants of the magnetless dual rotor wound field excited flux switching generator (DRWFEFSG) are comparatively analyzed for single rotor wind turbine (termed as machine I (MI)) and counter rotating wind turbine applications (termed as machine II (MII)) for household direct current (DC) microgrid system. First, design concept and integration to wind turbine system are discussed. Secondly, comprehensively performance analysis i.e., static analysis, dynamic load/speed analysis and electromagnetic performance analysis are executed. Finite element analysis (FEA) based static analysis evident that MI offers 7.6% higher torque in inner rotor whereas MII exhibits 18% higher torque in outer rotor. Dynamic respond unveils that in comparison to MII, MI suffers from the issue of voltage regulation. Additionally, electromagnetic analysis reveals that both MI and MII exhibits excellent response under variable field Magneto-motive force (MMF). Comparative analysis unveils that MII requires lower field MMF to achieve same response to counterpart MI. Quantitative analysis divulge efficiency of 88.49% and power factor of 0.93 in MI whereas MII at rated operating point demonstrates 85.9% efficiency and 0.96 power factor. Finally, effectiveness of the study and validity of DRWFEFSG for wind turbine applications are tested with hardware prototypes of both MI and MII that fairly matched with FEA results. • Generator design and comparative analysis for household DC microgrid system. • Generator design for co-rotating and counter rotating wind turbine application. • Generator for rooftop wind turbine integrated with wind turbine. • Improve power wind turbines generators. • Analysis and comparative study of generator design for wind power generation. [ABSTRACT FROM AUTHOR]

The cover image is based on the Research Article Generating characteristics and experimentation of counter rotating dual rotor wound field flux switching wind generator by Wasiq Ullah et al., https://doi.org/10.1049/elp2.12423. [ABSTRACT FROM AUTHOR]

Short moving primary and rigid low‐cost secondary are important requirements of linear machines designed for long stroke applications. In the race, linear permanent magnet flux switching machine (LPMFSM) is a competitive candidate by confining excitation sources to short mover, thus making stator robust and low cost (made of only iron). However, single‐sided LPMFSM exhibit a demerit of high normal (attraction) force due to its topology. In order to rectify the problem and enhance thrust force profile, two novel double‐sided LPMFSMs are proposed with dual stator and dual mover topologies. After stator pole study, both topologies with same design dimensions are analysed and compared by 2‐D finite element method here. Detailed analysis revealed that 12/14 DMLPMFSM exhibit low numerical values of thrust force ripples and detent force while maintaining average thrust force value. Hence, 12/14 DMLPMFSM is selected and optimised by structure‐based deterministic optimisation (SBDO) approach to further enhance thrust force profile. Finally, comparison of initial and optimised design of 12/14 DMLPMFSM is presented to validate optimisation procedure. [ABSTRACT FROM AUTHOR]

A novel single sided Linear Permanent Magnet Flux Switching Machine (LPMFSM) with twelve mover slots and fourteen stator teeth (12/14), having two additional end teeth on both sides of mover is presented. Presence of both Armature Winding (AW) and Permanent Magnet (PM) on mover structure results in completely passive, robust, and low cost stator. While, demerits such as less slot area, complex flux density distribution, and magnetic saturation caused by passive stator demands to be analyzed by time consuming and computationally complex numerical modelling techniques, i.e., Finite Element (FE) Analysis, requiring expensive hardware/software. In this paper, two cost effective and fast response analytical techniques are developed to analyze no-load performance of LPMFSM. Two no-load characteristics, i.e., open-circuit flux linkage and detent force are analyzed by Equivalent Magnetic Circuit (termed as analytical technique No. 1) and Lumped Parameter Equivalent Magnetic Circuit (termed as analytical technique No. 2). Both analytical methodologies are compared and validated with corresponding globally accepted FE Analysis. Analysis revealed that LPEMC is better approach for initial design of LPMFSM. [ABSTRACT FROM AUTHOR]

Front Cover: Investigation of low-cost dual port co-rotating dual rotor field excited flux switching generator for low-power rooftop wind turbine integrated with multi-port DC micro grid The cover image is based on the Research Article I Investigation of low-cost dual port co-rotating dual rotor field excited flux switching generator for low-power rooftop wind turbine integrated with multi-port DC micro grid i by Wasiq Ullah et al., https://doi.org/10.1049/rpg2.12561. [Extracted from the article]

The cover image is based on the Research Article Dual mechanical port power distribution in dual rotor permanent magnet flux switching generator for counter‐rotating wind turbine applications by Wasiq Ullah et al., https://doi.org/10.1049/rpg2.12450. [ABSTRACT FROM AUTHOR]

A dual mover yokeless multi-tooth (DMYMT) permanent magnet flux switching motor (PM-FSM) design is presented in this article for ropeless elevator applications. The excitation sources, including a field winding and permanent magnet, are on the short mover in the proposed design structure, whereas the stator is a simple slotted iron core, thus reducing the vertical transportation system cost. The operational principle of the proposed DMYMT in PM-FSM is introduced. The proposed dual mover yokeless multi-tooth Permanent Magnet Flux Switching Motor is analyzed and compared for various performance parameters in a Finite Element Analysis package. The proposed machine has high thrust force and cost-effectiveness compared to conventional dual permanent magnet motor. Finally, this paper also develops an analytical model for the proposed structure, validated by comparing it with Finite Element Analysis simulation results. Results show good agreement between analytical prediction and Finite Element Analysis results. [ABSTRACT FROM AUTHOR]

Double sided linear flux switching permanent magnet machines (DSLFSPMMs) exhibit high thrust force density, high efficiency, low cost and robust double salient secondary (stator) structures. The aforementioned unique features make DSLFSPMM suitable for long stroke applications. However, distorted flux linkage waveforms and high detent forces can exaggerate thrust force ripples and reduce their applicability in many areas. In order to enhance thrust force performance, reduce thrust force ripple ratio and total harmonic distortion (THD) of no-load flux linkages, two structure-based advancements are introduced in this work, i.e., asynchronous mover slot and stator tooth displacement technique (AMSSTDT) and the addition of an active permanent magnet end slot (APMES). Furthermore, single variable geometric optimization (SVGO) is carried out by the finite element method (FEM). [ABSTRACT FROM AUTHOR]