Design And Optimization Of Permanent Magnet Synchronous Motor With Axially Assembled Rotor

Permanent magnet synchronous motor(PMSM)has the advantages of high torque density and high power factor,but it has difficulty in weak magnetic field speed regulation.Synchronous reluctance motor has the advantages of speed regulation performance,but it suffers from lower torque density and significant torque ripple.Permanent magnet assisted synchronous reluctance motor(PMA-SynRM)has both certain torque output and weak magnetic field speed regulation capabilities,but there are significant torque ripple and core loss issues.Since the single motor topology structure has certain defects that limits the improvement of the overall performance of the motor,this thesis proposes an axial assembled rotor permanent magnet synchronous motor(AAR-PMSM).The rotor has an axial sandwiched structure,with axial laminated anisotropic(ALA)synchronous reluctance rotors on both sides and a spoke-type permanent magnet synchronous motor rotor in the middle.The torque stacking mechanism can be changed by flexibly designing the combination angles between different rotors,making the current phase angles approach the same value when the torque of each part is maximized,thereby improving the utilization rate of torque components.At the same time,the combination of the reluctance rotor and the spoke-type permanent magnet rotor can increase the motor’s torque output while broadening the motor’s speed regulation range,achieving a comprehensive improvement in motor performance.To demonstrate the advantages of the proposed AAR-PMSM,this thesis uses optimization design and comparative research methods to design the proposed motor and conducts a quantitative comparative analysis with traditional PMA-SynRM of the same size and specifications.The specific work of this thesis is as follows:(1)This thesis introduces the topology of traditional permanent magnet assisted synchronous reluctance motors(PMA-SynRM),and derives the mathematical model of PMA-SynRM based on coordinate transformation theory.The torque characteristics of traditional PMA-SynRM are analyzed,and the topology of the AAR-PMSM is determined based on the proposed design concept.The dynamic mathematical models of constant magnet synchronous engine and synchronous deviation engine were analyzed,and the AAR-PMSM dynamic mathematical model was obtained.The torque equation of the AAR-PMSM is derived,and the torque component variation diagram of the traditional PMA-SynRM is compared with that of the proposed model.(2)Using genetic optimization algorithm,the structural parameters of the assembled rotor permanent magnet motor are optimized.Firstly,the basic size and structure of the spoke-type permanent magnet rotor and the ALA synchronous reluctance rotor are respectively optimized by multi-objective design.Then,the axial parameters,such as the inter-rotor insulation layer,the misalignment configuration angle,and the axial length ratio,are studied and optimized,and the structural parameters of the AAR-PMSM are finally determined.(3)Based on finite element analysis,the performance of the AAR-PMSM is quantitatively analyzed through comparative study.The traditional PMA-SynRM of the same size and specifications is used as a reference model,and the unloaded and loaded characteristics of the proposed AAR-PMSM are analyzed,including back electromotive force,cogging torque,and load torque characteristics.At the same time,the weak magnetic field speed regulation performance of the AAR-PMSM is compared,and the wide speed regulation range of the AAR-PMSM structure is demonstrated under different axial length ratios.(4)Based on the mathematical model of the AAR-PMSM,the motor model is built using the MATLAB-Simulink module.The vector control system of the AAR-PMSM is constructed based on the built motor model,and the vector control of the AAR-PMSM is realized.The accuracy of the vector control system and the motor model is verified based on the simulation results of finite element analysis.