Coupling effects in hub motor and optimization for active suspension system to improve the vehicle and the motor performance

For electric vehicles (EVs) driven by in-wheel motor (IWM), the motor is directly integrated into the wheel. The coupling effects caused by the magnet gap deformation (MMG) in the motor and further enhanced by the unbalanced electromagnetic force (UEF) and the road excitation deteriorate the performance of EVs. However, few researchers have explored the coupling effects based on permanent magnet synchronous in-wheel motor and methods to suppress them. In this paper, the integrated model addressing the mechanical–electrical–magnetic coupling effects between the electromagnetic excitation in the permanent magnet synchronous motor (PMSM) and the transient dynamics in EVs is developed. The function mechanism of UEF-MMG deformation coupling circle is investigated and its influences on the performance of EV are explored. Moreover, using particle swarm optimization (PSO) algorithm, a multi-objective optimization method for active suspension system is proposed to solve the negative coupling effects. The simulation results indicate that the optimized active suspension system which considers the multi-field coupling effects of the IWM can effectively reduce the UEF caused by the eccentricity in the motor. Furthermore, it can attenuate the multi-field coupling effects and remarkably improve the ride comfort of EVs. The proposed multi-objective optimization method demonstrates a potential application in engineering practice. © 2020 Elsevier Ltd