Design And Analysis Of Doubly Salient Permanent Magnet Motor With ?-shaped Stator Iron Core Segments For Electric Vehicles

In recent years,people suffer from heavy fog weather continuously in our country,which endangers their health.As a big country of traditional fuel cars,to reduce greenhouse gas emissions is considered to be one of the efficient means to solve the deteriorating situation.Different from the traditional fuel vehicles,electric car is a modern means of transport which extracts the electric energy with rich resource,and wind energy and solar energy,the clean,non-polluting energy,thus have got strong support in China in recent years,rapid progress has been achieved.The motor,one of the key components in the electric cars,directly affects the overall performance of the electric cars.So it becomes more and more popular to study the new driving motor.Compared with other driving motors,permanent magnet motor,especially rare earth permanent magnet electrical machine has the advantages of high efficiency,small volume and is easy to maintain,which is widely used in the field of electric vehicles.In terms of the current application of permanent magnet motors,they can placed into stator permanent magnet motor and the rotor permanent magnet motor according to the location of the permanent magnet.Compared with stator permanent magnet motor,the rotor permanent magnet motor has a long history and has even been more widely used and deeper influence.Stator permanent magnet motor is a new type of motor,mainly includes three types: Doubly Salient Permanent Magnet motor(DSPM),Flux Switching Permanent Magnet motor(FSPM)and Flux Reversal Permanent Magnet motor(FRPM).Then compared with rotor permanent magnet motor,stator permanent magnet motor has the biggest advantages is: permanent magnets and windings are located in the stator,and the rotor of the motor is only the core of a salient,therefore the rotor permanent magnet motor has simple structure,high mechanical strength and is applied to high power density and high speed applications,which is in line with the requirements of the electric vehicles.DSPM motor,as stator permanent magnet motor,whose stator is mounted on a pair or more the permanent magnets on the basis of the switched reluctance motor,is a combination of switched reluctance motors' simple structure,high reliability and high power density and high efficiency of permanent magnet motors,etc.In the previous research,DSPM motor,however,the asymmetry of the magnetic circuit in DSPM motor design causes unbalanced three-phase no-load electromagnetic properties and the potential on high torque ripple of the motor,which fails to give full play of the advantages of DSPM motor.Based on the analysis above,taking the requirements for EV driven motor as the background,this paper proposes the ?-DSPM motor,whose structure itself has solved the problem of asymmetric three-phase magnetic circuit and the electromagnetic characteristics of the three-phase winding,reduce torque ripple of motor effectively and improve the motor performance.The main content of this paper include:1.This paper proposes a new ?-DSPM motor,of which the basic structure is described,and the operation principle is introduced.By the method of equivalent magnetic circuit,the air-gap magnetic flux density of is calculated.Based on the calculation,the motor winding configuration is designed;the conclusion was validated by the finite element software,and analysis the effective air gap flux density harmonic contribution to electromagnetic torque of the ?-DSPM motor.2.Some important parameters of the ?-DSPM motor are analyzed and optimized by the finite element method(FEM).3.Using finite element software JMAG,?-DSPM motor characteristics is studied,the air-gap magnetic flux density,no-load electromotive force and main features of the cogging torque are simulated.4.The simulation calculation was carried out on the loss of the ?-DSPM motor,mainly analyzes the stator and rotor core loss,copper loss,and eddy current loss of core and hysteresis losses shall be calculated separately.Finally according to each loss to calculate the efficiency of the motor.5.A prototype motor is developed and an experimental test bench is built.According to the validation experiments,it further proves that the designed motor is reasonable and feasible.