Compared with the single rotor wind turbine, a counter-rotating (CR) wind turbine with two rotor sets leads to twice power density. In this regard, dual stator CR (DSCR) permanent magnet flux switching generator (DSCR-PMFSG) is employed. However, in DSCR-PMFSG both rotor and armature parts are rotating and require slip rings for power transmission. The slip rings associate demerits of constant maintenance, poor speed regulation, increased cost, and additional slip ring losses, whereas DSCR-PMFSG offer lower flux and lesser power density. To overcome the demerits as mentioned earlier of DSCR-PMFSG, this paper proposed a novel dual rotor counter-rotating permanent magnet flux switching generator (DRCR-PMFSG) for wind turbine applications that eliminate the requirements of slip rings and retain brushless operation. The proposed DRCR-PMFSG share one stator connected back-to-back through a flux bridge that provides an alternate flux path between two mechanical ports associated with the inner rotor and outer rotor, contributing to the cumulative output. A detailed comparative analysis of DSCR-PMFSG and DRCR-PMFSG is performed under static characteristics, overload, and wide speed range to generate output power, voltage, current, power density, and efficiency. Quantitative comparative analysis under static analysis evident that proposed DRCR-PMFSG exhibits 33.29% higher flux, suppressed cogging torque and torque ripples up to 53.48% and 67.45%, respectively. Furthermore, a comprehensive quantitative analysis is performed under coupled overload and over-speed capability. The analysis exposes that in comparison with DSCRP-PMFSG, the proposed DRCR-PMFSG improves voltage regulation factor by 55.88%, output current enhanced by 67.9%, raise output voltage to 2.01 times, and power density to 1.72 times while maintaining the efficiency of 90.195% and achieving stable voltage profile with load variation. Finally, a detailed comparative analysis with conventional designs is performed and comprehensive mathematical modelling based on sub-domain model is developed accounting stator slot and rotor pole combinations, magnetic saturation, and winding configuration to validates finite element analysis (FEA) utilizing JMAG Designer v.20.1.

In this paper counter rotating (CR) dual rotor permanent magnet flux switching generator (CR-DRPMFSG) is designed and relatively studied with co-rotating DRPMFSG (CoR-DRPMFSG) for wind turbine applications. The developed CR-DRPMFSG and CoR-DRPMFSG share same stator linked with flux bridge which provide flux route. A comprehensive relative assessment of both CR-DRPMFSG and CoR-DRPMFSG are presented with static attributes, over-load, and over-speed capability for generating output voltage, output current, output power, power density, losses, and efficiency. Comparative study with static characteristics illustrates that developed CR-DRPMFSG shows 34.34% elevated phase flux which improve output power, cumulative output torque is improved by 23.86%, and suppressed cogging torque by 66.87% at CoR-DRPMFSG that results lower pulsation in instantaneous torque. Furthermore, a detailed performance analysis is investigated with different number of armature winding turns per phase and combined over-load and over-speed capability. Study discloses that in contrast with CoR-DRPMFSG counterpart CR-DRPMFSG offer 27.17% higher output power that results 1.25 times power density at a good voltage regulation factor of 18.67%. In additional, despite of 2.27% improvement of efficiency in case of turns analysis and 4.81% increase in overload and overspeed capability, contour efficiency map unveils that CR-DRPMFSG offer wide range of higher efficiency operating region during over-load and over-speed conditions accompany with stable voltage with the varying load profile.

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.

Computational complexity, magnetic saturation, complex stator structure and time consumption due to repeated iteration compels researchers to adopt alternate analytical model for initial design of electric machines especially Switched Flux Machine (SFM). To overcomes the abovesaid demerits, In this article alternate analytical sub-domain model (SDM) for magnetic field computation in Segmented PM switched flux consequent pole machine (SPMSFCPM) with flux bridge and flux barriers accounting boundary and interface conditions, radial magnetized PMs (RM-PMs) and circumferential magnetized PMs (CM-PMs), interaction between stator slots and inner/outer rotor topologies is proposed. Overall field domain is divided into air gap, stator slots and Permanent Magnet (PM) accounting influence of CM/RM-PMs under no-load and on-load conditions. Analytical expression of field domain is obtained by solving magnetic vector potential utilizing Maxwell’s equations. Based on the magnetic field computation especially no-load and on-load condition, Magnetic Flux Density (MFD) components, open-circuit flux linkage, mechanical torque and cogging torque are computed utilizing Maxwell Stress Tensor (MST) method. Moreover, developed analytical SDM is validated with globally accepted Finite Element Analysis (FEA) utilizing JMAG Commercial FEA Package v. 18.1 which shows good agreement with accuracy of ~98%. Hence, authors are confident to propose analytical SDM for initial design of SPMSFCPM to suppress computation time and complexity and eliminate requirements of expensive hardware and software tools.

In this paper, a novel dual port counter rotating dual rotor wound field flux switching generator (DPCRDR-WFFSG) is proposed for direct drive counter rotating wind power generation. Mechanism of gearless and brushless counter rotating operation of DPCRDR-WFFSG is discussed and simplified formulation is opted for possible combination of the rotor poles number $(N_r)$ . In proposed DPCRDR-WFFSG, dual electrical ports are formed of non-overlapped armature winding having shared toroidal field excitation winding whereas inner and outer rotors act as inner and outer port. These inner and outer port are thoroughly investigated for electromagnetic performance to search out optimum rotor poles combination. The rotor poles combinations are examined under uniform and non-uniform poles and comparatively studied. Based on simplified formulation, various combinations of the rotor pole numbers are searched out and found that under uniform poles operation, $N_r= 10$ and $N_r = 14$ offers comparatively better electromagnetic performance whereas in case of non-uniform rotor poles $N_r = 10/14$ further improves electromagnetic performance. Furthermore, analysis evident that in comparison with the inner port, outer port shows dominant contribution in electromagnetic performance whereas, in comparison with uniform rotor poles, the new approach of adopting non-uniform rotor poles improve electromagnetic performance. It is worth noting that non-uniform rotor poles in inner ports improves efficiency and power factor whereas in outer port, average torque and output power are enhanced. Finally, validity of uniform and non-uniform rotor poles design approach for DPCRDR-WFFSG is verified with four prototype that validated finite element analysis.

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 , high torque ripples , low average torque , lower torque density , power density 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 , , and . 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 higher up to 88.8%, suppress maximum up to 14.72% and offer 2.45 times and capabilities, when compared with the aforesaid state of the art.