The Design And Analysis Of Permanent Magnet Synchronous Motor For Electric Vehicle Application

With the development of human society, the demand of energy is growing rapidly.However, most fossil fuels especially petroleum are more and more expensive due toenergy crisis. Meanwhile, the use of fossil fuels results in increasingly seriousenvironmental issues. Therefore the developing of green and environmentally-friendlyenergy has become a society-wide consensus. Having experienced the Beijing haze andPM2.5, the public is focusing their concentration on automobile-exhaust pollution which isa main source of air contamination. So it’s extremely urgent to put low-emission andzero-emission new energy automobiles into use. As a result, electric vehicle is attachedgreat importance conforming to the trend. Many countries and automobile manufacturersare spending huge amounts of money researching electric vehicles among which motordrive system is the key point. Unlike conventional applications and design requirements ofpermanent magnet motor, electric vehicle motor drive system should have manycapabilities such as high efficiency, wide speed range, high overload capacity, solidstructure, small size and light weight that will definitely bring bigger challenges to thedesign of PM machine. This paper is to design and manufacture a35kW permanent magnetsynchronous prototype motor which is used in electric bus, then the experimental prototypeis tested to verify its performances.Above all, this paper makes a detailed comparison on various types of motor drivesystems in accordance with the working environment and performance requirements. Then,deep analysis of PMSM drive system is carried out on the basis of design requirements. Thefocus is on the PMSM of V-type embedded rotor structure.Having carefully examined the performance requirement of the PMSM beforehand,this paper gives a reasonable design on electromagnetic loading, rotor structure, windingtype and dimensions with the help of field-circuit calculation software SPEED and FEAsoftware Ansoft. After many trials of optimal design, the geometry as well aselectromagnetic parameters and performances are ultimately determined.Rigorous requirement of structure and performance as it is, this paper tries to adjustthe motor’s cooling system and analyze motor thermal field to meet the demand oftemperature rise by using ANSYS Workbench. Moreover, for the PM machine will rotate inhigh speed, analysis of the mechanical structure is also conducted for purpose of ensuringstability of mechanical structure. In addition, the demagnetization of permanent magnet occurred in short-circuit is analyzed and evaluated as well.Finally, the experimental prototype is built and tested in order to verify whether theperformances meet the design specification or not. The results of prototype tests haveshown that the motor design has basically reached its goal.