| Permanent magnet(PM)motors with a high-power density and high efficiency have been widely used in aerospace,rail transit,electric vehicle(EV),high-end control of Computer Numerical Control(CNC),and robots.PM motors can be divided into rotor PM motors and stator PM motors according to the different placement positions of PMs.Rotor permanent magnet flux-switching(RPMFS)motor which evolved from the design concept of the stator permanent magnet flux-switching(SPMFS)motor was first introduced to mitigate the undesirable stator-teeth saturation in the SPMFS motor,but also unveil additional merits of an enhanced electromagnetic output torque capacity,overload capability,and splendid or impressive heat dissipating capacity.However,the rotors of the existing RPMFS motors are segregated or in modular form and need non-magnetic materials as rotor support,to avoid the PM magnetic field being closed in the rotor,which will reduce the mechanical robustness of the rotor and increase the machining complexity of the motor.Meanwhile,the traditional RPMFS motor adopts a three-phase winding configuration,which is difficult to continue to operate after open-circuit and short-circuit faults conditions,hence,threatening the operation safety of major equipment.Therefore,how to build or design an RPMFS motor with high fault tolerance and high mechanical robustness has become an urgent problem to be solved.Therefore,this thesis or research work introduces the Multi-phase fractional-slot concentrated winding,fault-tolerant teeth,and inverted T-shaped PM structure into the conventional RPMFS motor,and proposes a new five-phase fault-tolerant RPMFS motor.The innovative PM structure of the motor makes it have an integrated rotor,convenient processing,multiple operating degrees of freedom and is suitable for high-reliability situations or applications.Based on the new motor structure,the following research results are obtained in this thesis:1.The topology of a new five-phase fault-tolerant RPMFS motor is proposed.Besides,the slot-pole combination,the dimension equation,the stator,and winding configuration selection in addition to the PM structure design is expounded or presented in detail to determine the basic structure and main design dimensions of the 20-slot and 11-pole pairs five-phase fault-tolerant RPMFS motor.The novelty of the proposed motor lies in its unique auxiliary PM arrangement,which ensures that the generated magnetic flux will not be short-circuited through the rotor core,and in addition,solves the disadvantage of rotor separation of the traditional RPMFS motor,and enhances the output torque of the motor.Meanwhile,compared with the traditional motor with modular rotor topology,the proposed motor eliminates the non-magnetic support in the rotor,which makes it easier to manufacture,and enhances the mechanical integrity and robustness of the rotor.2.Based on the simplified magnetomotive force(MMF)-permeance model,the operation principle of the motor is analyzed,and the torque generation mechanism of the motor is revealed.The air-gap flux density generated by the separate excitation of the PM and the armature winding of the motor is analyzed,respectively.And then,the working harmonics of the interaction between the two airgap flux densities are discovered or determined.Further,the torque generation mechanism of the motor is analyzed based on the Maxwell stress tensor method.3.To improve the output torque and reduced the torque ripple of the proposed motor,the multiobjective optimization design of the traditional RPMFS motor and the new fault-tolerant RPMFS motor is carried out respectively.The key parameters of the motor are designed in layers by sensitivity design.Then,the response surface methodology(RSM)and the barebones multiobjective particle swarm optimization(BB-MOPSO)algorithm are combined effectively to realize the improvement of the electromagnetic performances.And the finite element single parameter scanning optimization method is used to optimize the low sensitivity parameters.Finally,the comprehensive torque performance optimization design of the motor is realized.4.The electromagnetic performances of the two motors before and after optimization,such as no-load back EMF,output torque,and torque ripple,are compared by using finite element analysis(FEA).It is found that the electromagnetic performance of the new fault-tolerant RPMFS is better than that of the traditional RPMFS motor before and after optimization.5.The efficiency,loss,and mechanical robustness of the two motors are analyzed and compared.It is found that the performance of the proposed motor is better than that of the traditional rotor permanent magnet flux switching motor,which proves the feasibility of the proposed motor.6.A new fault-tolerant RPMFS motor is processed or manufactured and tested.The electromagnetic performance,fault-tolerant performance of single-phase open-circuit fault,and single-phase shortcircuit fault are analyzed respectively,and the advantages of the new five-phase RPMFS motor are verified. |
