Design and thermal analysis on high torque low speed fractional-slot concentrated windings in-wheel traction motor

This paper investigates a fractional-slot concentrated windings surface-mounted permanent magnet synchronous machine for low speed high torque traction application. This motor is designed with the combination of equivalent magnetic circuit method and finite-element analysis for the consideration of calculation time and accuracy. Attention is focused on the electromagnetic, thermal analysis and optimization design of this machine, which is crucial for the high torque low speed application. Parameter sensitivity analysis of liner thickness, cooling water volume flow rate and interface of stator laminations and housing on heat dissipation is covered in this paper. Performance of the machine are calculated with equivalent magnetic circuit and finite element analysis method and design techniques are described for improving the machine efficiency especially at high torque operating point.