To overcome the problems existing in the practical application of traditional in-wheel motors used for electric vehicles, an integrated double rotor in-wheel motor was proposed, which can realize three drive modes to meet variable operating condition requirements of the vehicle. The process of switching between different drive modes affects the ride comfort of a vehicle. Taking the mode switching from a single inner motor drive to a dual-motor coupling drive as a research object, a dynamic modeling method of drive mode switching based on the switching system was proposed. According to the critical conditions of each state transition, the switching rules expressed by the segmental constant function were designed. At the engagement stage of electromagnetic clutch II, the torque coordination control strategy based on model predictive control (MPC) and control allocation was proposed. The simulation results show that the proposed strategy can effectively reduce the impact degree of a vehicle and the slipping-friction work of the clutch on the premise of ensuring the fast response of mode switching and the steady increase in vehicle speed. The switching quality of the mode-switching process is effectively improved. In addition, the drive mode switching control of the double rotor in-wheel motor prototype was tested, which proves its ability to operate in multi-drive mode.

In order to develop an electrical continuously variable transmission (E-CVT) to replace mechanical power coupling equipment applied in series-parallel hybrid electric vehicle (HEV), this paper proposes a magnetic-field modulated brushless dual-mechanical port motor with Halbach array permanent magnets, which has a more compact structure. The operating characteristics are analyzed by the lever analogy. It is concluded that the motor can realize the speed and torque decoupling between the engine and the wheel, which meet multi-mode operation requirements for HEV. To realize the multi-objective design of torque output, torque ripple and usage amount of permanent magnets, an optimization scheme combined parameter sensitivity with response surface methodology is adopted. The trade-offs among the optimization objectives are considered, then the key structural parameters and its optimal values are efficiently determined. Based on a two-dimensional model, the electromagnetic performances are simulated and analyzed. The results show that, after the parameters optimization, the no-load back electromotive force (EMF) has better sinusoidal characteristic, and the torque ripples and cogging torque peaks of the motor have been significantly reduced. Furthermore, a prototype motor is tested. The experimental results are consistent with the simulation results, which demonstrates the validity of the proposed structure and parameter optimization method.

In order to improve the lateral stability and handling performance of in-wheel motor drive electric vehicles, a coordinated control method considering lateral stability and differential power-assisted steering performance is proposed. A vehicle dynamics model with two degrees of freedom is established, in which the influence of system disturbance is considered. At the same time, the effect of differential torque on vehicle power-assisted steering control was analyzed, and a differential power-assisted steering control method of vehicle was designed based on referenced steering wheel torque. In response to the coupling relationship and dynamic game problem between the lateral stability control system and the differential power-assisted steering control system, a coordinated control system with a vehicle lateral stability module and a differential power-assisted steering module was designed based on the Nash equilibrium game theory, achieving comprehensive optimization of multi-objective performance. Corresponding simulation tests were conducted in the co-simulation vehicle model, and the results show that the proposed coordinated control method can achieve the differential power-assisted steering control function of vehicle while ensuring lateral stability.