Research On Interior-modulating-rotor Axial-magnetic-field-modulated Double-rotor Machine

With the increasingly severe energy crisis and environmental problems,new energy vehicles are receiving more and more attention.Among them,hybrid vehicles are considered to be the best solution during the transition period from fuel vehicles to pure electric vehicles with the advantages of long mileage and low emissions.In this paper,an IMR-AMFMDRM(Interior-Modulating-Rotor Axial-Magnetic-FieldModulated Double-Rotor Machine),which adopts a pure electromagnetic scheme to replace the planetary gear mechanism in traditional hybrid vehicles such as Toyota Prius,is researched to avoid inherent vibration noise,wear and maintenance problems of mechanism.The axial topology structure improves the utilization of axial space,reducing the volume of the variable speed system;Interior-modulating-rotor structure can reduce the unbalanced magnetic pulling force of the permanent magnet rotor,avoiding the hollow structure and improving the mechanical strength and processing technology with strong engineering practicality.The main research content of this article includes the following parts:First,the basic working principle of IMR-AMFMDRM is analyzed.The theoretical analysis of IMR-AMFMDRM is based on the principle of magnetic field modulation,and the torque equation and speed equation of IMR-AMFMDRM are derived.Three-dimensional finite element simulation was used to verify the theoretical analysis,and the unbalanced magnetic pulling forces of the conventional structure and the interior-modulating-rotor structure were compared and analyzed.Secondly,the two-dimensional analytical model of IMR-AMFMDRM is established.Based on the principle of permanent magnet energy invariance,the calculation formula of equivalent two-dimensional analytical model geometry size is derived,the vector equation of magnetic field is solved using the sub domain method,the expressions of magnetic density distribution of inner and outer air gap,and the analytical expressions of machine performance parameters such as phase winding flux,back EMF,electromagnetic torque and axial magnetic pull are derived.Through three-dimensional finite element simulation,the accuracy and consistency of the twodimensional analytical model for air gap flux density distribution and machine performance parameters are evaluated.The effects of different polar logarithm matching schemes on cogging torque,electromagnetic torque and torque fluctuation are studied by two-dimensional analytical model and three-dimensional finite element simulation,and the best polar logarithm matching scheme is obtained.Finally,the causes of the calculation errors of the two-dimensional analytical model are analyzed by the three-dimensional finite element simulation,and the two-dimensional analytical results are modified by the three-dimensional finite element simulation,so that the two-dimensional analytical model can take the end magnetic flux leakage into account.The calculation accuracy of the two-dimensional analytical method and the improved two-dimensional analytical method is analyzed by the three-dimensional finite element simulation.In this paper,three-dimensional finite element simulation and improved two-dimensional analytical method are compared and analyzed when the parameters of the machine geometry change.The electromagnetic torque optimization algorithm based on the improved twodimensional analytical model is established,and the feasibility of the optimization algorithm and the accuracy of the optimization results are verified by the finite element simulation.