Permanent magnets (PMs) have been widely used in different types of electrical machines to improve their performance. This paper introduces a novel multi-tooth hybrid-excited switched reluctance motor (MT-HESRM) with PMs placed between the end teeth of the adjacent modules. Thanks to the innovative method of embedding PMs, a unique design is developed. First, the operating principle of the motor is explained and the magnetic circuit model (MCM) of the motor is analyzed. The magnetic characteristics in terms of flux density, flux linkage, inductance, and torque are obtained and compared with those of its PMless counterpart. The mathematical model of the reluctance and PM torques is presented. The reluctance and PM torques are decoupled using the finite element analysis and the torque contribution of the PMs is discussed. The steady-state operations of both motors with both current chopping and single-pulse controls are analyzed and compared under different speeds. Finally, both motors are manufactured, the laboratory tests are done, and the experimental results are extracted. Both the simulation and test results elucidate that the MT-HESRM, which has only three small PMs as auxiliary flux sources, has unique features in terms of high output power and torque with a negligible cogging torque.

This paper proposes an enhanced-torque switched reluctance motor with two sets of permanent magnets (PM-SRM) embedded inside the stator yoke and the end teeth of the neighboring modules. The PMs contribute to intensify the air-gap flux density and reduce the magnetic saturation in the stator poles. As a result, the output torque can be enhanced to a significant extent. The working principle of the proposed PM-SRM is clarified using its magnetic circuit model (MCM). The characteristics of the PM-SRM are obtained and compared with classical 12/8 and 6/5 SRMs and hybrid reluctance motors (HRMs) in terms of static and average torque and average torque per PMs volume. The steady-state performance of the PM-SRM in terms of current and torque waveforms is carried out, and the PM-SRM is compared with considered SRMs and HRMs in terms of output torque, power, and efficiency. All the comparisons demonstrate the out-performance of the proposed PM-SRM over other SRMs and HRMs. To validate the simulation results, a prototype of the PM-SRM is manufactured and the experimental results are obtained. Both the simulation and experimental results are indicative of the fact that the proposed PM-SRM can gain high torque and high PM utilization factor, simultaneously.

In this paper, a new multi-tooth switched reluctance motor (MT-SRM) is proposed and then based on the original topology, three novel multi-tooth hybrid reluctance motors (MT-HRMs) are introduced to improve the torque characteristics of the SRM. The proposed structures are an MT-HRM with permanent magnets (PMs) between the side teeth of the adjacent modules, an MT-HRM with PMs in the yoke, and finally an MT-HRM with dual-PM configuration. The operating principles of the MT-HRMs are illustrated and the flux adjusting effect and outstanding torque production ability of the PMs are demonstrated through the theoretical and simulation results. The flux distributions and static torque and flux linkage profiles of the motors are obtained and compared. The four proposed motors are compared in terms of the steady-state current and torque waveforms. All the simulation results indicate that the PM-assisted structures can achieve higher torque and power than their PMless counterpart with deploying only three/six small PMs. The four motors are prototyped and the experimental results are carried out. Both the experimental and simulation results prove the effectiveness of the proposed MT-HRMs.

In this article, three new toothed biased flux permanent magnet (PM) motors are introduced and studied, each of which has a specific arrangement of excitation (dc field/PM) and flux path (series/parallel). This results in three main structures, namely, hybrid excited toothed slot-PM (HETSPM), toothed biased flux PM (TBFPM) with series flux path, and, finally, toothed biased flux slot PM (TBFSPM) with hybrid flux path. The TBFSPM structure has improved the average torque, torque ripple, and efficiency compared to other stator-PM motors. The HETSPM structure has improved the average torque per PM, and the TBFPM structure features a very low-torque ripple profile compared to other stator-PM motors. All the topologies have shown a good PM demagnetization resistance and lower PM loss compared to other structures. Moreover, a new Carter’s coefficient is introduced to increase the accuracy of harmonic analysis for split-tooth structures by modeling the nonlinear effect of fringing flux with a new transition function, which has increased the accuracy by 20% compared to the traditional approach. The theoretical analyses have been checked by the 2-D finite element method (FEM), and the TBFSPM structure is prototyped and tested to validate the simulation analyses.