Study on a Novel In-Wheel Motor Driving System Driven by Two Permanent Magnet Synchronous Disc Motors

Abstract

The electrical driving system is crucial to the performance of electric vehicles (EVs). It is problematic for an in-wheel motor (IWM) driven by a single motor to satisfy certain dynamics requirements or to remain highly efficient at full operating conditions. In this paper, a novel IWM driving system driven by two permanent magnet synchronous disc motors (PMSDMs) with a planetary differential gear train (PDGT) is put forward. The PMSDMs are designed based on the parameters and dynamic indicators of the vehicle. Thereafter, the PMSDMs are optimized from aspects of the rotor skewing angle and pole arc coefficient and verified by finite element analysis (FEA). Then the characteristic coefficient of PDGT is optimized through non-dominated sorting genetic algorithm II (NSGA-II) combined with dynamic programming (DP). The economic performance improves by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$5.0\%$</tex-math></inline-formula> and dynamic performance improves by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$4.4\%$</tex-math></inline-formula> with the characteristic coefficient optimized from 3 to 1.65. Meanwhile, the economic performance of the novel dual-motor IWM shows significant improvement compared to the traditional single-motor IWM in simulation. Furthermore, a prototype is developed and tested. Both the simulation and experimental results reveal the feasibility and effectiveness of the proposed novel IWM driving system.