Design of synchronous reluctance motor for hybrid electric vehicles

The paper deals with the design of a synchronous reluctance motor suited for hybrid electric vehicles. At first, the focus is on rotor design. In particular an useful approach is proposed to choose the proper angles of the flux-barrier ends with the aim of reducing the torque ripple due to the slot harmonics. In the second part a comparison among different rotor arrangements (one, two and three flux-barriers per pole) is presented. Furthermore an improvement in terms of low ripple and high average torque is given thanks to the ”Machaon” configuration. The third part of the paper deals with the analysis of the improved layout. The current vector control method used to maximize the torque according to the voltage and current constraints is shown. Saturation effects are taken into account. The impact of electrical design on the mechanical characteristics of the rotor (and natural frequencies) is discussed as well. At last the predicted mechanical characteristics of the reluctance motor are presented: torque versus speed behavior, power losses and power factor. The efficiency map of the machine based on Finite Elements analysis is also reported.