Design Of Permanent Magnet Assisted Synchronous Reluctance Motor For Electric Vehicle

In order to solve the problem of energy shortage and environmental pollution,pure electric vehicle has become an important development direction of automobile industry.The popularization and development of electric vehicle is affected by its driving motor.The permanent magnet auxiliary synchronous reluctance motor studied in this paper has the advantages of small size,high power density,low cost and so on.It is very suitable for electric vehicle driving,but its structure is different from the conventional permanent magnet synchronous motor.There are multiple magnetic barriers on the rotor,which makes its design process different from the conventional permanent magnet synchronous motor.In this paper,combined with the technical characteristics of permanent magnet assisted synchronous reluctance motor,the research is carried out from the following aspects:Firstly,the rotor structure of the SRM is studied.The rotor structure of this kind of motor is complex,usually composed of multilayer magnetic barrier structure and permanent magnet.The rotor with u,V and C-shaped magnetic barriers is studied respectively.The effects of different layers of magnetic barriers on induction parameters,the ratio of reluctance torque to permanent magnet torque,torque ripple and speed torque characteristics are compared,and the most suitable rotor structure is selected.Secondly,the vibration noise of PMSM is calculated and analyzed.In order to save calculation resources and calculation period,a quasi analytical calculation program is developed to calculate the vibration and noise,and the accuracy of the quasi analytical calculation program is verified by experiments.Based on the quasi analytical calculation program,the factors affecting the vibration and noise of PMSM are analyzed,including the pole The influence of arc coefficient,the number of permanent magnets,the shape of permanent magnets and the way of magnetization on the vibration and noise is discussed.Several measures are put forward to suppress the vibration and noise of the permanent magnet assisted synchronous reluctance motor,including the opening of the auxiliary slot of the rotor,the design of the segmented inclined pole of the rotor and the asymmetric structure of the rotor.The accuracy of the method is verified by the finite element calculation.Finally,a permanent magnet auxiliary synchronous reluctance motor for vehicle is designed based on the above research contents.The design of key parameters is discussed,including the selection of main dimensions,stator winding design,rotor structure selection and back EMF selection.Through the finite element simulation to check the motor,the performance of the motor is excellent.