Design And Research Of V-type Magnetic Flux Leakage Controllable Embedded Permanent Magnet Motor

In recent years,with environmental pollution and energy crisis becoming more and more serious,governments and scholars from all over the world have reached a consensus that clean and environmentally friendly electric vehicles will become the main theme of the future development of the automotive industry.Permanent magnet motor has been widely used in electric vehicle drive because of its advantages of high power/torque density,high operating efficiency and excellent dynamic performance.However,due to the inherent defects of the motor itself,such as the constant air gap magnetic field and the narrow speed range of weak magnetic field,it can't fully meet the comprehensive driving requirements of the new generation of electric vehicles.Under such research background,a Leakage Flux Controllable Interior Permanent Magnet(LFC-IPM)motor with wide speed area and high efficiency is proposed in this paper.Based on the traditional IPM motor,the motor achieves the performance characteristics of flux leakage controllable through ingenious structure design,thus effectively expanding the motor's flux-weakening speed range,and realizing the effective expansion of the motor's high-efficiency operation area.Firstly,this paper introduces the importance of developing electric vehicle technology,and analyses the research status of various types of wide speed motor.Considering the limitations of traditional motors,this paper studies and analyses how to realize the constant power and wide speed regulation operation of motors.On this basis,a new design concept,leakage flux controllable,is introduced,and the topology of LFC-IPM motor is proposed.Secondly,drawing on the experience of traditional motor design,a new LFC-IPM motor design scheme is proposed.After selecting the pole slot ratio and rated parameters,the main dimensions of the motor are determined by the general formula of motor design,and the initial design of the motor is completed.Thirdly,on the basis of the initial design and the principle of leakage flux controllable,the stator and rotor structures of the new LFC-IPM motor are proposed,and the main dimensions of stator windings and permanent magnets are calculated.By analyzing the main optimization objectives and design variables of the motor,a hierarchical optimization method which combines single parameter scanning method with response surface analysis method is proposed.In the single-parameter scanning method,three optimization objectives of the size of permanent magnet,namely,output torque,torque ripple and iron loss,are analyzed,and the optimal parameters are determined.In response surface analysis,four optimization objectives of rotor magnetic barrier size,namely output torque,torque ripple,iron loss and power factor,are analyzed,and the optimal size is synthetically selected to determine the final model of the motor.Fourthly,the basic electromagnetic performances of LFC-IPM motor and traditional motor are compared by finite element analysis,including air-gap flux density,permanent magnet flux linkage and back-EMF,magnetic field distribution,torque characteristics,cogging torque characteristics and leakage flux controllable characteristics.In addition,in order to highlight the advantages of the designed motor,the operation characteristics,efficiency characteristics and multi-driving-cycle conditions of the motor are compared and analyzed in the range of flux-weakening speed regulation.Finally,according to the final model,the prototype of LFC-IPM motor is manufactured,and the related performance is tested and verified.The test contents include: no-load back-EMF waveform of motor,verification of leakage flux controllable characteristic and torque waveform of LFC-IPM motor under different driving cycle conditions.The results verify the rationality of LFC-IPM motor design.