Design And Analysis Of Cooling System For A Flux-Switching Permanent Magnet Machine In Electric Vehicles

Recently,flux-switching permanent magnet(FSPM)machines have attracted more and more researchers' attention.In FSPM machines,both magnets and armature windings are located in stators,thus the FSPM machines have the effect of magnetic flux concentrator.Both stators and rotors are doubly salient and the windings are concentrated.As a result,the air gap magnetic field can be large.The windings are complementary and can reduce or even offset the high order harmonic component in magnetic flux and back electromotive force.The structures of FSPM motors not only can avoid the risk of magnets falling out at high speed,but also facilitate the cooling of the magnets.Based on the advantages mentioned above,a flux-switching permanent magnet machine which serves as an integrated starter-generator in hybrid electric vehicles is analyzed in this thesis.Finite element method is applied to calculate the loss of the FSPM machine and the temperature distribution of the machine under different working conditions is analyzed in FLUENT.Under the same working condition,temperature rising experiments are conducted and the temperature of different components are detected to verify the thermal simulation.Finally,the performance of the current cooling jacket is investigated and optimized.The main contents are as follows:1.The background of the research is introduced,alos the research actuality of permanent magnet machines' loss caculation,thermal analysis and cooling systems' designs are introduced.2.Considering the DC component of machine's current,the time step element method is applied to calculate the core loss of machine,also the core loss of FSPM machine is calculated in Maxwell and JMAG for verification.The eddy current losses in magnets and water jacket are obtained by three dimensional finite element method(FEM)in JMAG.For verification,the no-load loss is obtained from the no-load tests performed on the hybrid platform.3.Steady thermal analysis and transient thermal analysis of motor are performed in FLUENT.Temperature rising experiments under different cooling conditions are conducted on hybrid platform to verify the thermal analysis of the FSPM machine.4.The inlet velocities' influence on the water jacket's performance is investigated and temperature rising experiments under different cooling conditions where the inlet velocities are different are performed for verification.Base on the temperature rising experiments,the geometry parameters of water jackets are optimized to improve the water jacket's performance.