Transient characteristics analysis of linear flux-switching permanent magnet machines for precision control

A dynamical dq model is proposed for a linear flux-switching permanent magnet（LFSPM） machine which is suitable for high-precision control applications.The operation principle of the prototype machine is analyzed using the finite element method（FEM）,and the parameters,such as the back electromotive force（EMF） and the phase flux linkage,are calculated.The calculated and measured results reveal that the back EMF and the flux linkage are essentially sinusoidal,and the variation of the phase flux linkage profile of the LFSPM machine is similar to that of the linear surface permanent magnet（LSPM） machine.Based on this,a dynamical dq model and a simulation control model are proposed.The simulation results are compared with the test results obtained from a DSP-based control platform,which verifies that the model is correct and effective.Moreover,the model can be used for design optimization and control development.

Performance Analysis and Comparison for Two Topologies of Flux-Switching Permanent Magnet Machine

Flux-switching permanent magnet(FSPM)machine is a kind of stator-typed permanent magnet machine,which is suitable for driving electric vehicles and hybrid electric vehicles because of their large power/torque density and high efficiency.The axial field flux-switching permanent magnet machine(AFFSPMM)and radial field flux-switching permanent magnet machine(RFFSPMM)with H-typed iron cores are reached and compared in this paper.On the condition of the same outer diameters and total volumes,the electromagnetic performances of the two machines are analyzed and compared by the three-dimensional finite element method,including the air gap flux density,inductance,back electromotive force(EMF),electromagnetic torque and loss.The finite element results show that the copper loss of AFFSPMM is higher than that of RFFSPMM at the rated load,however,the total loss of AFFSPMM is lower than that of the RFFSPMM.Meanwhile,AFFSPMM has greater torque than RFFSPMM in the constant power range.The related experiments are done to validate the finite element results,which are basically consistent with experiment results.

Reduction of Cogging Torque in Permanent Magnet Flux-Switching Machines

Permanent magnet flux-switching machine (PMFSM) is a relatively new structure. Available literatures mainly focused on its general design procedure and performance analysis. In this paper, Finite Element Method (FEM) is taken to ana-lyze various design techniques to reduce the cogging torque in a prototype 12/10-pole PMFSM.

Electromagnetic-thermal Coupled Analyses and Joint Optimisation of Electrically-excited Flux-switching Linear Machines

Electrically-excited flux-switching machines are advantageous in simple and reliable structure,good speed control performance,low cost,etc.,so they have arouse wide concerns from new energy field.However,they have much lower torque density/thrust density compared with the same type PM machines.To overcome this challenge,electromagnetic-thermal coupled analysis is carried out with respect to water-cooled electrically-excited flux-switching linear machines(EEFSLM).The simulation results indicate that the conventional fixed copper loss method(FCLM)is no longer suitable for high thrust density design,since it is unable to consider the strong coupling between the electromagnetic and thermal performance.Hence,a multi-step electromagnetic-thermal joint optimisation method is proposed,which first ensures the consistency between the electromagnetic and thermal modelling and then considers the effect of different field/armature coil sizes.By using the proposed joint optimisation method,it is found that the combination of relatively large size of field coil and relatively low field copper loss is favourable for achieving high thrust force for the current EEFSLM design.Moreover,the thrust force is raised by 13-15%compared with using the FCLM.The electromagnetic and thermal performance of the EEFSLM is validated by the prototype test.