Design And Development Of Anti-directional-dual-rotor Motor For Electric Vehicles

Drive motor is the heart of electric vehicles, whether its design is reasonable or notdirectly affects the performance of electric vehicles. Therefore, the drive motor technologyhas been regarded as one of the key technologies of electric vehicles, and a lot of attentionshave been paid by researchers around the world. Anti-directional-dual-rotor motor (ADDRM)is a new sort of motor, which has two mechanical shafts that rotate oppositely. Power can beoutput from two axles so that ADDRM has greater power density than traditional motors,which makes it suitable to be drive motors of electric vehicles. Moreover, ADDRM candirectly drive the vehicle wheels through proper speed reduction (change of direction). Thus,the driving axle can be simplified by eliminating the mechanical differential. The design andstability research of planetary-gear-reduced ADDRM have been carried out in this thesis,according to a scheme of multi-bridge driving system with independent intellectual propertyrights for oil-electric hybrid electric vehicles. The main work is carried out as follows:(1) According to the technical requirements of this research, the basic parameters of bothADDRM and planetary reducers are determined, and gear design is completed. Then theprimary structural design of both ADDRM and planetary reducers is carried out.(2) In order to verify the electromagnetic performances, a two-dimensional finite elementanalysis model of ADDRM’s electromagnetic field is built, and simulations of no-loadcondition, full-load condition, over-load condition as well as the cogging torque are carriedout. The results show that the design of ADDRM is quite reasonable and all technicalrequirements are met.(3) The effects of the boundary size of structural optimization for inner rotor core on thekey electromagnetic performance, such as the average magnetic flux density in air gap, theaverage magnetic flux density in the bridge, the average electromagnetic torque and theaverage eddy loss in the inner rotor core are analyzed by virtue of Ansoft/Maxwell, hence theboundary size is determined. Topology optimization under stress constraint was carried out tothe inner rotor core as well as the key parts of reducers by utilizing Hyperworks/Optistruct. The results show that the inner rotor core achieves a weight loss of20.68%after optimization,while the key parts of reducers achieve a weight loss of over30%in average afteroptimization.(4) The stability analysis of ADDRM in both open-loop and closed-loop (including infield weakening regime) are conducted based on the small signal method. The results showthat ADDRM will become instable at some work points in open-loop, while some specificclosed-loop control scheme can be adopted to make it stable consistently. Open-loop as wellas closed-loop simulations of ADDRM are carried out in Matlab/Simulink environment toverify the analysis results. Eigenvalue sensitivities of system matrices are computed, and theinfluences of system parameters to system stability in different control modes are clarified.(5) The benchmark test of functional prototype is conducted to test some of the systemperformance in no load condition as well as partial-load condition.