| In recent years,Electric Vehicle(EV)has become the main development trend of the automotive industry.Among them,hub-driven electric vehicle has been widely concerned and studied in the automotive industry because of its compact structure,high flexibility and energy efficiency,and has achieved a certain degree of industrial application in electric vehicles.Hub motor is a key component of the hub drive system of electric vehicle,and its performance directly determines the dynamic performance of the drive system.It is worth mentioning that the Permanent Magnet Vernier(PMV)motor with external rotor,due to its excellent performance advantages,such as low speed,large torque,simple structure and high efficiency,has potential application prospects in the application of direct drive in electric vehicle hub.In this paper,a new type of V-Shaped Permanent Magnet Vernier(V-SPMV)motor is proposed based on the analysis of the shortcomings of existing PMV motors and the driving requirements of electric vehicle hub system.Firstly,this paper introduces the background and significance of the research,makes a detailed analysis of the development status of electric vehicle centralized drive and hub drive motor at home and abroad,and clarifies the feasibility of PMV in electric vehicle wheel drive application.In view of the shortcomings of existing PMV motors,the topology structure of V-SPMV motor is proposed.In addition,this paper analyzes the magnetic field modulation principle of V-SPMV motor,and determines the initial size of V-SPMV motor through torque and power size equation,selection of stator and rotor,determination of pole slot ratio and calculation of winding parameters.Secondly,the design flow of V-SPMV motor is introduced,and the stator rotor design,the selection of polar groove ratio and the design of winding parameters of V-SPMV motor are analyzed in detail to obtain the initial structure of V-SPMV motor.After obtaining the initial size,the optimization objectives of the motor are determined according to the driving requirements of the wheel hub,the parameters are divided into sensitive layer and non-sensitive layer based on the sensitivity of the design variables to the target.For the design variables of the sensitive layer,the parameters are optimized by response surface method and continuous non-linear programming method;and the design variables of the non-sensitive layer are optimized by the single parameter scanning method.Then,after obtaining the optimal model of V-SPMV motor,the basic electromagnetic properties of the initial model and the optimal model of the motor are compared and analyzed,including magnetic field distribution,no-load back EMF,torque performance and other basic electromagnetic performance.Then,in order to evaluate the performance of the V-SPMV motor more comprehensively,the comprehensive performance of the initial model and the optimal model of the motor are compared and analyzed,including the load capacity,inductance characteristics,power factor,loss efficiency and operation characteristics of the motor.Finally,according to the prototype of the V-SPMV motor’s optimal model,an experimental platform was built to test the no-load back EMF,steady-state operating characteristics and dynamic response characteristics of the motor.The finite element analysis and experimental results verify the rationality and effectiveness of the V-SPMV motor design and optimization method.The relevant studies showed that the V-SPMV motor can be applied to the electric vehicle wheel drive. |
