Optimization Design and Analysis of a Hybrid Permanent Magnet Flux-Switching Motor with Compound Rotor Configuration

This paper proposes a type of flux-switching permanent magnet(FSPM)motor,where the design concept of the hybrid permanent magnets(HPM)and the compound rotor are incorporated into the motor design.In such design,the proposed motor can not only realize the significant reduction of NdFeB volume,but also artfully convert external magnetic flux leakage into the air-gap field to achieve competitive torque density and desirable PM usage efficiency.For extensive investigation,two topologies of the HPM are designed and analyzed for the proposed motor,which consist of the parallel-magnetic-hybrid(PMH)mode and serial-magnetic-hybrid(SMH)mode.To fully exploit the potential advantages of the proposed motor,a multi-objective optimization design is conducted,where the response surface method(RSM)and sequential non-linear programming(SNP)method are purposely utilized.After optimization,the electromagnetic performances of the motor with PMH mode and SMH mode are evaluated and compared by using finite element method(FEM),which include the back-EMF,cogging torque,output torque,and so on.Furthermore,the partial demagnetization of the ferrite PM is also investigated in the paper.Finally,the theoretical analysis and simulation study verify the effectiveness of the proposed motor and corresponding optimization design.

Cogging Torque Reduction in Axial Flux PMSM with Different Permanent Magnet Combination

With the increasing requirement for the mechanical vibration and acoustic noise of the permanent magnet synchronous motor(PMSM)drive system,the demand for cogging torque reduction of PMSM has been considerably increased.To solve the problem of oversized cogging torque of axial flux PMSM,a rotor topology with hybrid permanent magnet is proposed to weaken the cogging torque.Firstly,the expression of the cogging torque of the axial flux motor is derived,and the influence of the pole-arc ratio of the permanent magnet on the cogging torque is analyzed.Secondly,the rotor structure with hybrid permanent magnet is adopted to reduce the cogging torque.According to the analytical analysis,the constraints of the size and pole-arc ratio between the hybrid permanent magnets are obtained,and the two permanent magnets related to the minimum cogging torque are determined.And the analysis results are verified by the finite element simulation.Furthermore,the motor performance with and without the hybrid permanent magnet is compared with each other.Finally,the cogging torque is significantly reduced by adopting a rotor structure with hybrid permanent magnets.

Recent Advances in Variable Flux Memory Machines for Traction Applications: A Review

This paper overviews the recent advances in variable flux memory machines(VFMMs)for traction applications with particular reference to newly emerged machine topologies and related control strategies.Due to the use of flux memorable low coercive force(LCF)magnets,the air-gap flux of VFMM can be flexibly varied via a magnetizing current pulse.Thus,the copper loss associated with the flux weakening current and high-speed iron loss can be significantly reduced,and hence high efficiency can be achieved over a wide speed and torque/power operation.These merits make VFMM potentially attractive for electric vehicle(EV)applications.Various novel VFMMs are reviewed with particular reference to their topologies,working principle,characteristics and related control techniques.In order to tackle the drawbacks in the existing VFMMs,some new designs are introduced for performance improvement.Then,the electromagnetic characteristics of an exemplified EV-scaled switched flux memory machine and various benchmark traction machine choices,such as induction machine,synchronous reluctance machines,as well as commercially available Prius 2010 interior permanent magnet(IPM)machine are compared.Finally,the key challenges and development trends of VFMM are highlighted,respectively.

Suspension Power Optimization of Unbalanced Structure Permanent-electro Hybrid Magnet Using Genetic Algorithm

The permanent magnet electromagnetic hybridmagnet (PEHM) has the advantages of low energy consumptionand a large suspension air gap. In this study, an unbalancedPEHM structure is proposed, which combines the advantages ofthe previous hybrid magnet structure. First, by establishing themagnetic circuit model of the new hybrid magnet structure, theinfluence of magnetic field distribution on the working magneticcircuit of the magnet is analyzed, and the method of magneticforce correction calculation of the new structure magnet isgiven. Then, the validity of the magnetic calculation method isverified by the 3D finite element method (FEM). Furthermore, theaverage suspension power force ratio is used as the optimizationgoal, and the system parameters of the hybrid magnet under aworking air gap of 6–10 mm and a load condition of 15000–20000 N are optimized by a genetic algorithm. Compared withthe previous hybrid magnet, the optimized hybrid magnet systemcan maintain lower power consumption under comprehensiveworking conditions.